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Sample records for thermophilic biohydrogen production

  1. Thermophilic Biohydrogen Production

    DEFF Research Database (Denmark)

    Karakashev, Dimitar Borisov; Angelidaki, Irini

    2011-01-01

    Dark fermentative hydrogen production at thermophilic conditions is attractive process for biofuel production. From thermodynamic point of view, higher temperatures favor biohydrogen production. Highest hydrogen yields are always associated with acetate, or with mixed acetate- butyrate type...... fermentation. On the contrary the hydrogen yield decreases, with increasing concentrations of lactate, ethanol or propionate. Major factors affecting dark fermentative biohydrogen production are organic loading rate (OLR), pH, hydraulic retention time (HRT), dissolved hydrogen and dissolved carbon dioxide...... concentrations, and soluble metabolic profile (SMP). A number of thermophilic and extreme thermophilic cultures (pure and mixed) have been studied for biohydrogen production from different feedstocks - pure substrates and waste/wastewaters. Variety of process technologies (operational conditions...

  2. Comparing the Bio-Hydrogen Production Potential of Pretreated Rice Straw Co-Digested with Seeded Sludge Using an Anaerobic Bioreactor under Mesophilic Thermophilic Conditions

    Directory of Open Access Journals (Sweden)

    Asma Sattar

    2016-03-01

    Full Text Available Three common pretreatments (mechanical, steam explosion and chemical used to enhance the biodegradability of rice straw were compared on the basis of bio-hydrogen production potential while co-digesting rice straw with sludge under mesophilic (37 °C and thermophilic (55 °C temperatures. The results showed that the solid state NaOH pretreatment returned the highest experimental reduction of LCH (lignin, cellulose and hemi-cellulose content and bio-hydrogen production from rice straw. The increase in incubation temperature from 37 °C to 55 °C increased the bio-hydrogen yield, and the highest experimental yield of 60.6 mL/g VSremoved was obtained under chemical pretreatment at 55 °C. The time required for maximum bio-hydrogen production was found on the basis of kinetic parameters as 36 h–47 h of incubation, which can be used as a hydraulic retention time for continuous bio-hydrogen production from rice straw. The optimum pH range of bio-hydrogen production was observed to be 6.7 ± 0.1–5.8 ± 0.1 and 7.1 ± 0.1–5.8 ± 0.1 under mesophilic and thermophilic conditions, respectively. The increase in temperature was found useful for controlling the volatile fatty acids (VFA under mechanical and steam explosion pretreatments. The comparison of pretreatment methods under the same set of experimental conditions in the present study provided a baseline for future research in order to select an appropriate pretreatment method.

  3. Biohydrogen production by anaerobic fermentation of waste. Final project report

    Energy Technology Data Exchange (ETDEWEB)

    Karakashev, D.; Angelidaki, I.

    2009-01-15

    The objective of this project was to investigate and increase dark fermentative hydrogen production from organic wastes by optimizing important process parameters (reactor type, pH, temperature, organic loading, retention time, inoculation strategy, microbial composition). Labscale experiments were carried out at the Department of Environmental Engineering, Technical University of Denmark. A two steps process for hydrogen production in the first step and methane production in the second step in serial connected fully mixed reactors was developed and could successfully convert organic matter to approx. 20-25 % hydrogen and 15-80 % to methane. Sparging with methane produced in the second stage could significantly increase the hydrogen production. Additionally it was shown that upflow anaerobic sludge blanket (UASB) reactor system was very promising for high effective biohydrogen production from glucose at 70 deg C. Glucose-fed biofilm reactors filled with plastic carriers demonstrated high efficient extreme thermophilic biohydrogen production with mixed cultures. Repeated batch cultivations via exposure of the cultures to increased concentrations of household solid waste was found to be most useful method to enhance hydrogen production rate and reduce lag phase of extreme thermophilic fermentation process. Low level of pH (5.5) at 3-day HRT was enough to inhibit completely the methanogenesis and resulted in stable extreme thermophilic hydrogen production. Homoacetogenisis was proven to be an alternative competitor to biohydrogen production from organic acids under thermophilic (55 deg. C) conditions. With respect to microbiology, 16S rRNA targeted oligonucleotide probes were designed to monitor the spatial distribution of hydrogen producing bacteria in sludge and granules from anaerobic reactors. An extreme thermophilic (70 deg. C), strict anaerobic, mixed microbial culture with high hydrogen producing potential was enriched from digested household waste. Culture

  4. Biohydrogen production from pig slurry in a CSTR reactor system with mixed cultures under hyper-thermophilic temperature (70 oC)

    International Nuclear Information System (INIS)

    Kotsopoulos, Thomas A.; Fotidis, Ioannis A.; Tsolakis, Nikolaos; Martzopoulos, Gerassimos G.

    2009-01-01

    A continuous stirred tank reactor (CSTR) (750 cm 3 working volume) was operated with pig slurry under hyper-thermophilic (70 o C) temperature for hydrogen production. The hydraulic retention time (HRT) was 24 h and the organic loading rate was 24.9 g d -1 of volatile solid (VS). The inoculum used in the hyper-thermophilic reactor was sludge obtained from a mesophilic methanogenic reactor. The continuous feeding with active biomass (inoculum) from the mesophilic methanogenic reactor was necessary in order to achieve hydrogen production. The hyper-thermophilic reactor started to produce hydrogen after a short adapted period of 4 days. During the steady state period the mean hydrogen yield was 3.65 cm 3 g -1 of volatile solid added. The high operation temperature of the reactor enhanced the hydrolytic activity in pig slurry and increased the volatile fatty acids (VFA) production. The short HRT (24 h) and the hyper-thermophilic temperature applied in the reactor were enough to prevent methanogenesis. No pre-treatment methods or other control methods for preventing methanogenesis were necessary. Hyper-thermophilic hydrogen production was demonstrated for the first time in a CSTR system, fed with pig slurry, using mixed culture. The results indicate that this system is a promising one for biohydrogen production from pig slurry.

  5. Acclimatization Study for Biohydrogen Production from Palm Oil Mill Effluent (POME) in Continuous-flow System

    Science.gov (United States)

    Idris, N.; Lutpi, N. A.; Wong, Y. S.; Tengku Izhar, T. N.

    2018-03-01

    This research aims to study the acclimatization phase for biohydrogen production from palm oil mill effluent (POME) by adapting the microorganism to the new environment in continuous-flow system of thermophilic bioreactor. The thermophilic fermentation was continuously loaded with 0.4 L/day of raw POME for 35 days to acclimatize the microorganism until a steady state of biohydrogen production was obtained. The significance effect of acclimatization phase on parameter such as pH, microbial growth, chemical oxygen demand (COD), and alkalinity were also studied besides the production of biogas. This study had found that the thermophilic bioreactor reach its steady state with 1960 mL/d of biogas produced, which consist of 894 ppm of hydrogen composition.

  6. Biohydrogen production from beet molasses by sequential dark and photofermentation

    NARCIS (Netherlands)

    Özgür, E.; Mars, A.E.; Peksel, B.; Louwerse, A.; Yücel, M.; Gündüz, U.; Claassen, P.A.M.; Eroglu, I.

    2010-01-01

    Biological hydrogen production using renewable resources is a promising possibility to generate hydrogen in a sustainable way. In this study, a sequential dark and photofermentation has been employed for biohydrogen production using sugar beet molasses as a feedstock. An extreme thermophile

  7. Food waste and food processing waste for biohydrogen production: a review.

    Science.gov (United States)

    Yasin, Nazlina Haiza Mohd; Mumtaz, Tabassum; Hassan, Mohd Ali; Abd Rahman, Nor'Aini

    2013-11-30

    Food waste and food processing wastes which are abundant in nature and rich in carbon content can be attractive renewable substrates for sustainable biohydrogen production due to wide economic prospects in industries. Many studies utilizing common food wastes such as dining hall or restaurant waste and wastes generated from food processing industries have shown good percentages of hydrogen in gas composition, production yield and rate. The carbon composition in food waste also plays a crucial role in determining high biohydrogen yield. Physicochemical factors such as pre-treatment to seed culture, pH, temperature (mesophilic/thermophilic) and etc. are also important to ensure the dominance of hydrogen-producing bacteria in dark fermentation. This review demonstrates the potential of food waste and food processing waste for biohydrogen production and provides a brief overview of several physicochemical factors that affect biohydrogen production in dark fermentation. The economic viability of biohydrogen production from food waste is also discussed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Biohydrogen production: prospects and limitations to practical application

    Energy Technology Data Exchange (ETDEWEB)

    Levin, D.B. [Univ. of Victoria, Dept. of Biology and Inst. for Integrated Energy Systems, Victoria, British Columbia (Canada); Pitt, L.; Love, M. [Univ. of Victoria, Inst. for Integrated Energy Systems, Victoria, British Columbia (Canada)

    2003-07-01

    Hydrogen may be produced by a number of processes, including electrolysis of water, thermocatalytic reformation of hydrogen rich organic compounds, and biological processes. Currently, hydrogen is produced, almost exclusively, by electrolysis of water or by steam reformation of methane. Biological production of hydrogen (Biohydrogen) technologies provide a wide range of approaches to generate hydrogen, including Direct biophotolysis, Indirect Biophotolysis, Photo-fermentations, and Dark-fermentation. The practical application of these technologies to every day energy problems, however, is unclear. In order to assess which biohydrogen systems may be practical when combined with fuel cell technologies, we have calculated the size of biohydrogen bioreactors that would be required to power Proton Exchange Membrane (PEM) Fuel Cells of various sizes. Our analysis suggests that light-driven biohydrogen systems (Direct Photolysis, Indirect Photolysis, and Photo-fermentation) do not produce H{sub 2} at rates that are sufficient to power PEMFCs of sufficient size to be of practical use. Thermophilic and extreme thermophilic biohydrogen systems would require very large bioreactors (in the range of approximately 2900 L to 14,600 L) to provide sufficient H{sub 2} to power PEMFCs of 1.5 kW to 5.0 kW, respectively. Some Dark-fermentation systems, however, appear promising. Bioreactors of 500 L and 1000 L, designed so that H{sub 2} is rapidly removed from the culture medium, would be sufficient to power PEMFCs of 2.5 kW and 5.0 kW, respectively. Further research and development aimed at increasing rates of synthesis and final yields of H{sub 2} are essential if biohydrogen systems are to be of practical use. (author)

  9. Biohydrogen production: prospects and limitations to practical application

    International Nuclear Information System (INIS)

    Levin, D.B.; Pitt, L.; Love, M.

    2003-01-01

    Hydrogen may be produced by a number of processes, including electrolysis of water, thermocatalytic reformation of hydrogen rich organic compounds, and biological processes. Currently, hydrogen is produced, almost exclusively, by electrolysis of water or by steam reformation of methane. Biological production of hydrogen (Biohydrogen) technologies provide a wide range of approaches to generate hydrogen, including Direct biophotolysis, Indirect Biophotolysis, Photo-fermentations, and Dark-fermentation. The practical application of these technologies to every day energy problems, however, is unclear. In order to assess which biohydrogen systems may be practical when combined with fuel cell technologies, we have calculated the size of biohydrogen bioreactors that would be required to power Proton Exchange Membrane (PEM) Fuel Cells of various sizes. Our analysis suggests that light-driven biohydrogen systems (Direct Photolysis, Indirect Photolysis, and Photo-fermentation) do not produce H 2 at rates that are sufficient to power PEMFCs of sufficient size to be of practical use. Thermophilic and extreme thermophilic biohydrogen systems would require very large bioreactors (in the range of approximately 2900 L to 14,600 L) to provide sufficient H 2 to power PEMFCs of 1.5 kW to 5.0 kW, respectively. Some Dark-fermentation systems, however, appear promising. Bioreactors of 500 L and 1000 L, designed so that H 2 is rapidly removed from the culture medium, would be sufficient to power PEMFCs of 2.5 kW and 5.0 kW, respectively. Further research and development aimed at increasing rates of synthesis and final yields of H 2 are essential if biohydrogen systems are to be of practical use. (author)

  10. Biohydrogen Production by the Thermophilic Bacterium Caldicellulosiruptor saccharolyticus: Current Status and Perspectives

    Directory of Open Access Journals (Sweden)

    Servé W. M. Kengen

    2013-01-01

    Full Text Available Caldicellulosiruptor saccharolyticus is one of the most thermophilic cellulolytic organisms known to date. This Gram-positive anaerobic bacterium ferments a broad spectrum of mono-, di- and polysaccharides to mainly acetate, CO2 and hydrogen. With hydrogen yields approaching the theoretical limit for dark fermentation of 4 mol hydrogen per mol hexose, this organism has proven itself to be an excellent candidate for biological hydrogen production. This review provides an overview of the research on C. saccharolyticus with respect to the hydrolytic capability, sugar metabolism, hydrogen formation, mechanisms involved in hydrogen inhibition, and the regulation of the redox and carbon metabolism. Analysis of currently available fermentation data reveal decreased hydrogen yields under non-ideal cultivation conditions, which are mainly associated with the accumulation of hydrogen in the liquid phase. Thermodynamic considerations concerning the reactions involved in hydrogen formation are discussed with respect to the dissolved hydrogen concentration. Novel cultivation data demonstrate the sensitivity of C. saccharolyticus to increased hydrogen levels regarding substrate load and nitrogen limitation. In addition, special attention is given to the rhamnose metabolism, which represents an unusual type of redox balancing. Finally, several approaches are suggested to improve biohydrogen production by C. saccharolyticus.

  11. Biohydrogen production from household solid waste (HSW) at extreme-thermophilic temperature (70 degrees C) - Influence of pH and acetate concentration

    DEFF Research Database (Denmark)

    Liu, Dawei; Min, Booki; Angelidaki, Irini

    2008-01-01

    Hydrogen production from household solid waste (HSW) was performed via dark fermentation by using an extreme-thermophilic mixed culture, and the effect of pH and acetate on the biohydrogen production was investigated. The highest hydrogen production yield was 257 +/- 25 mL/gVS(added) at the optimum...... pH of 7.0. Acetate was proved to be inhibiting the dark fermentation process at neutral pH, which indicates that the inhibition was caused by total acetate concentration not by undissociated acetate. Initial inhibition was detected at acetate concentration of 50 mM, while the hydrogen fermentation...

  12. Potential for biohydrogen and methane production from olive pulp

    DEFF Research Database (Denmark)

    Gavala, Hariklia N.; Skiadas, Ioannis V.; Ahring, Birgitte Kiær

    2005-01-01

    The present study investigates the potential for thermophilic biohydrogen and methane production from olive pulp, which is the semi-solid residue coming from the two-phase processing of olives. It focussed on: a) production of methane from the raw olive pulp, b) anaerobic bio-production of hydrogen...... from the olive pulp, and c) subsequent anaerobic treatment of the hydrogen-effluent with the simultaneous production of methane. Both continuous and batch experiments were performed. The hydrogen potential of the olive pulp amounted to 1.6 mmole H-2 per g TS. The methane potential of the raw olive pulp...... and hydrogen-effluent was as high as 19 mmole CH4 per g TS. This suggests that olive pulp is an ideal substrate for methane production and it shows that biohydrogen production can be very efficiently coupled with a subsequent step for methane production....

  13. Optimizing the impact of temperature on bio-hydrogen production from food waste and its derivatives under no pH control using statistical modelling

    Science.gov (United States)

    Arslan, C.; Sattar, A.; Ji, C.; Sattar, S.; Yousaf, K.; Hashim, S.

    2015-11-01

    The effect of temperature on bio-hydrogen production by co-digestion of sewerage sludge with food waste and its two derivatives, i.e. noodle waste and rice waste, was investigated by statistical modelling. Experimental results showed that increasing temperature from mesophilic (37 °C) to thermophilic (55 °C) was an effective mean for increasing bio-hydrogen production from food waste and noodle waste, but it caused a negative impact on bio-hydrogen production from rice waste. The maximum cumulative bio-hydrogen production of 650 mL was obtained from noodle waste under thermophilic temperature condition. Most of the production was observed during the first 48 h of incubation, which continued until 72 h of incubation. The decline in pH during this interval was 4.3 and 4.4 from a starting value of 7 under mesophilic and thermophilic conditions, respectively. Most of the glucose consumption was also observed during 72 h of incubation and the maximum consumption was observed during the first 24 h, which was the same duration where the maximum pH drop occurred. The maximum hydrogen yields of 82.47 mL VS-1, 131.38 mL COD-1, and 44.90 mL glucose-1 were obtained from thermophilic food waste, thermophilic noodle waste and mesophilic rice waste, respectively. The production of volatile fatty acids increased with an increase in time and temperature in food waste and noodle waste reactors whereas they decreased with temperature in rice waste reactors. The statistical modelling returned good results with high values of coefficient of determination (R2) for each waste type and 3-D response surface plots developed by using models developed. These plots developed a better understanding regarding the impact of temperature and incubation time on bio-hydrogen production trend, glucose consumption during incubation and volatile fatty acids production.

  14. Optimizing the impact of temperature on bio-hydrogen production from food waste and its derivatives under no pH control using statistical modelling

    OpenAIRE

    Arslan, C.; Sattar, A.; Ji, C.; Sattar, S.; Yousaf, K.; Hashim, S.

    2015-01-01

    The effect of temperature on bio-hydrogen production by co-digestion of sewerage sludge with food waste and its two derivatives, i.e. noodle waste and rice waste, was investigated by statistical modelling. Experimental results showed that increasing temperature from mesophilic (37 °C) to thermophilic (55 °C) was an effective mean for increasing bio-hydrogen production from food waste and noodle waste, but it caused a negative impact on bio-hydrogen production from rice waste...

  15. Optimizing the impact of temperature on bio-hydrogen production from food waste and its derivatives under no pH control using statistical modelling

    OpenAIRE

    A. Sattar; C. Arslan; C. Ji; S. Sattar; K. Yousaf; S. Hashim

    2015-01-01

    The effect of temperature on bio-hydrogen production by co-digestion of sewerage sludge with food waste and its two derivatives, i.e. noodle waste and rice waste, was investigated by statistical modelling. Experimental results showed that increasing temperature from mesophilic (37 °C) to thermophilic (55 °C) was an effective mean for increasing bio-hydrogen production from food waste and noodle waste, but it caused a negative impact on bio-hydrogen productio...

  16. The influence of calcium supplementation on immobilised mixed microflora for biohydrogen production

    Science.gov (United States)

    Lutpi, Nabilah Aminah; Shian, Wong Yee; Izhar, Tengku Nuraiti Tengku; Zainol, Noor Ainee; Kiong, Yiek Wee

    2017-04-01

    This study is aim to study the effect of calcium as supplement in attached growth system towards the enhancement of the hydrogen production performance. The effects of calcium ion for thermophilic biohydrogen production were studied by using a mixed culture, from palm oil mill effluent sludge and granular activated carbon (GAC) as the support material. Batch experiments were carried out at 60°C by feeding the anaerobic sludge bacteria with sucrose-containing synthetic medium at an initial pH of 5.5 under anaerobic conditions. The repeated batch cultivation process was conducted by adding different concentration of calcium at range 0.025g/L to 0.15g/L. The results showed that the calcium at 0.1 g/L was the optimal concentration to enhance the fermentative hydrogen production under thermophilic (60°C) conditions.

  17. Thermophilic anaerobic co-digestion of organic fraction of municipal solid waste (OFMSW) with food waste (FW): Enhancement of bio-hydrogen production.

    Science.gov (United States)

    Angeriz-Campoy, Rubén; Álvarez-Gallego, Carlos J; Romero-García, Luis I

    2015-10-01

    Bio-hydrogen production from dry thermophilic anaerobic co-digestion (55°C and 20% total solids) of organic fraction of municipal solid waste (OFMSW) and food waste (FW) was studied. OFMSW coming from mechanical-biological treatment plants (MBT plants) presents a low organic matter concentration. However, FW has a high organic matter content but several problems by accumulation of volatile fatty acids (VFAs) and system acidification. Tests were conducted using a mixture ratio of 80:20 (OFSMW:FW), to avoid the aforementioned problems. Different solid retention times (SRTs) - 6.6, 4.4, 2.4 and 1.9 days - were tested. It was noted that addition of food waste enhances the hydrogen production in all the SRTs tested. Best results were obtained at 1.9-day SRT. It was observed an increase from 0.64 to 2.51 L H2/L(reactor) day in hydrogen productivity when SRTs decrease from 6.6 to 1.9 days. However, the hydrogen yield increases slightly from 33.7 to 38 mL H2/gVS(added). Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Comparison of biohydrogen production processes

    International Nuclear Information System (INIS)

    Manish, S.; Banerjee, Rangan

    2008-01-01

    For hydrogen to be a viable energy carrier, it is important to develop hydrogen generation routes that are renewable like biohydrogen. Hydrogen can be produced biologically by biophotolysis (direct and indirect), photo-fermentation and dark-fermentation or by combination of these processes (such as integration of dark- and photo-fermentation (two-stage process), or biocatalyzed electrolysis, etc.). However, production of hydrogen by these methods at commercial level is not reported in the literature and challenges regarding the process scale up remain. In this scenario net energy analysis (NEA) can provide a tool for establishing the viability of different methods before scaling up. The analysis can also be used to set targets for various process and design parameters for bio-hydrogen production. In this paper, four biohydrogen production processes (dark-fermentation, photo-fermentation, two-stage process and biocatalyzed electrolysis) utilizing sugarcane juice as the carbon source, are compared with base case method steam methane reforming (SMR) on the basis of net energy ratio, energy efficiency and greenhouse gas (GHG) emissions. It was found that when by-products are not considered, the efficiencies of biological hydrogen processes are lower than that of SMR. However, these processes reduce GHG emissions and non-renewable energy use by 57-73% and 65-79%, respectively, as compared to the SMR process. Efficiencies of biohydrogen processes increase significantly when by-products are considered hence by-products removal and utilization is an important issue in biological hydrogen production. (author)

  19. Potential use of thermophilic dark fermentation effluents in photofermentative hydrogen production by Rhodobacter capsulatus

    Energy Technology Data Exchange (ETDEWEB)

    Ozgura, E.; Afsar, N.; Eroglu, I. [Middle East Technical University, Department of Chemical Engineering, 06531 Ankara (Turkey); De Vrije, T.; Claassen, P.A.M. [Wageningen UR, Agrotechnology and Food Sciences Group, Wageningen UR, P.O. Box 17, 6700 AA Wageningen (Netherlands); Yucel, M.; Gunduz, U. [Middle East Technical University, Department of Biology, 06531 Ankara (Turkey)

    2010-12-15

    Biological hydrogen production by a sequential operation of dark and photofermentation is a promising route to produce hydrogen. The possibility of using renewable resources, like biomass and agro-industrial wastes, provides a dual effect of sustainability in biohydrogen production and simultaneous waste removal. In this study, photofermentative hydrogen production on effluents of thermophilic dark fermentations on glucose, potato steam peels (PSP) hydrolysate and molasses was investigated in indoor, batch operated bioreactors. An extreme thermophile Caldicellulosiruptor saccharolyticus was used in the dark fermentation step, and Rhodobacter capsulatus (DSM1710) was used in the photofermentation step. Addition of buffer, Fe and Mo to dark fermentor effluents (DFEs) improved the overall efficiency of hydrogen production. The initial acetate concentration in the DFE needed to be adjusted to 30-40 mM by dilution to increase the yield of hydrogen in batch light-supported fermentations. The thermophilic DFEs are suitable for photofermentative hydrogen production, provided that they are supplemented with buffer and nutrients. The overall hydrogen yield of the two-step fermentations was higher than the yield of single step dark fermentations.

  20. Continuous thermophilic biohydrogen production in packed bed reactor

    International Nuclear Information System (INIS)

    Roy, Shantonu; Vishnuvardhan, M.; Das, Debabrata

    2014-01-01

    Highlights: • Continuous H 2 production in whole cell immobilized system was compared with CSTR. • Suitability of environment friendly support matrix for immobilization of whole cells was explored. • Pack bed reactor showed higher stability as compared to CSTR at lower HRTs. • Flow cytometry study showed the influence of recycle ratio on viability of cells. • Novel approach to find out the effect of NADH/NAD + ratio during H 2 production. - Abstract: The present research work deals with the performance of packed bed reactor for continuous H 2 production using cane molasses as a carbon source. Maximum H 2 production rate of 1.7 L L −1 h −1 was observed at a dilution rate and recycle ratio of 0.8 h −1 and 0.6, respectively which was corresponding to the lowest NADH/NAD + ratio. This suggests that the utilization of NADH pool for H 2 and metabolite production might lead to decrement in NADH/NAD + ratio. Thus NADH/NAD + ratio show inverse relation with hydrogen production. The substrate degradation kinetics was investigated as a function of flow rate considering the external film diffusion model. At a flow rate of 245 mL h −1 , the contribution of external film mass transfer coefficient and first order substrate degradation constant were 55.4% and 44.6% respectively. Recycle ratio of 0.6 improved the hydrogen production rates by 9%. The viable cell count was directly proportional to the recycle ratio (within the range 0.1–0.6). Taguchi design showed the significant influence of the feed pH on continuous H 2 production followed by dilution rate and recycle ratio. Thus environmentally friendly and cheaper solid matrix like coconut coir could be efficiently used for thermophilic continuous hydrogen production

  1. Biohydrogen production using waste activated sludge disintegrated by gamma irradiation

    International Nuclear Information System (INIS)

    Yin, Yanan; Wang, Jianlong

    2015-01-01

    Highlights: • The waste activated sludge could be disintegrated by gamma irradiation. • The disintegrated sludge could be used for biohydrogen production. • Combined alkali-irradiation treatment achieved the highest solubilization of sludge. - Abstract: The biohydrogen production using the disintegrated and dissolved sludge by gamma irradiation was studied. The experimental results showed that gamma irradiation and irradiation combined with alkali pretreatment could disintegrate and dissolve waste activated sludge for biohydrogen production. The alkali-irradiation treatment of the sludge at pH = 12 and 20 kGy achieved the highest disintegration and dissolution, i.e., it could destroy the cell walls and release organic matters (such as soluble COD, polysaccharides and protein) into the solution. The disintegrated sludge could be used as a low-cost substrate for biohydrogen production

  2. Bio-hydrogen Production Potential from Market Waste

    Directory of Open Access Journals (Sweden)

    Lanna Jaitalee

    2010-07-01

    Full Text Available This research studied bio-hydrogen production from vegetable waste from a fresh market in order to recover energy. A series of batch experiments were conducted to investigate the effects of initial volatile solids concentration on the bio-hydrogen production process. Lab bench scale anaerobic continuous stirred-tank reactors (CSTR were used to study the effect of substrate and sludge inoculation on hydrogen production. Three different concentrations of initial total volatile solids (TVS of organic waste were varied from 2%, 3% and 5% respectively. The pH was controlled at 5.5 for all batches in the experiment. The results showed that bio-hydrogen production depended on feed-substrate concentration. At initial TVS content of 3%, the highest hydrogen production was achieved at a level of 0.59 L-H2/L at pH 5.5. The maximum hydrogen yield was 15.3 ml H2/g TVS or 8.5 ml H2/g COD. The composition of H2 in the biogas ranged from 28.1-30.9% and no CH4 was detected in all batch tests.

  3. Sago Biomass as a Sustainable Source for Biohydrogen Production by Clostridium butyricum A1

    Directory of Open Access Journals (Sweden)

    Mohamad Faizal Ibrahim

    2013-12-01

    Full Text Available Biohydrogen production from biomass is attracting many researchers in developing a renewable, clean and environmental friendly biofuel. The biohydrogen producer, Clostridium butyricum A1, was successfully isolated from landfill soil. This strain produced a biohydrogen yield of 1.90 mol H2/mol glucose with productivity of 170 mL/L/h using pure glucose as substrate. The highest cumulative biohydrogen collected after 24 h of fermentation was 2468 mL/L-medium. Biohydrogen fermentation using sago hampas hydrolysate produced higher biohydrogen yield (2.65 mol H2/mol glucose than sago pith residue (SPR hydrolysate that produced 2.23 mol H2/mol glucose. A higher biohydrogen productivity of 1757 mL/L/h was obtained when using sago hampas hydrolysate compared to when using pure glucose that has the productivity of 170 mL/L/h. A comparable biohydrogen production was also obtained by C. butyricum A1 when compared to C. butyricum EB6 that produced a biohydrogen yield of 2.50 mol H2/mol glucose using sago hampas hydrolysate as substrate. This study shows that the new isolate C. butyricum A1 together with the use of sago biomass as substrate is a promising technology for future biohydrogen production.

  4. Biohydrogen production from glucose in upflow biofilm reactors with plastic carriers under extreme thermophilic conditions (70(degree)C)

    DEFF Research Database (Denmark)

    Zheng, H.; Zeng, Raymond Jianxiong; Angelidaki, Irini

    2008-01-01

    Biohydrogen could efficiently be produced in glucose-fed biofilm reactors filled with plastic carriers and operated at 70°C. Batch experiments were, in addition, conducted to enrich and cultivate glucose-fed extremethermophilic hydrogen producing microorganisms from a biohydrogen CSTR reactor fed...

  5. Start up study of UASB reactor treating press mud for biohydrogen production

    International Nuclear Information System (INIS)

    Radjaram, B.; Saravanane, R.

    2011-01-01

    Anaerobic digestion of press mud mixed with water for biohydrogen production was performed in continuous fed UASB bioreactor for 120 days. Experiment was conducted by maintaining constant HRT of 30 h and the volume of biohydrogen evolved daily was monitored. Various parameters like COD, VFA, Alkalinity, EC, Volatile solids, pH with respect to biohydrogen production were monitored at regular interval of time. SBPR was 10.98 ml g -1 COD reduced d -1 and 12.77 ml g -1 VS reduced d -1 on peak yield of biohydrogen. COD reduction was above 70 ± 7%. Maximum gas yield was on the 78th day to 2240 ml d -1 . The aim of the experiment is to study the startup process of UASB reactor for biohydrogen production by anaerobic fermentation of press mud. The inoculum for the process is cow dung and water digested in anaerobic condition for 30 days with municipal sewage sludge. The study explores the viability of biohydrogen production from press mud which is a renewable form of energy to supplement the global energy crisis. -- Highlights: → Feasibility of biohydrogen production from press mud was explored in this study. The gas yield was maximum on the 78th day to 2240 ml d -1 with H 2 % of 52-59%. Biohydrogen yield was about 890 ml kg -1 press mud added d -1 . Press mud is identified as an excellent potential waste to tap energy.

  6. Batch Fermentative Biohydrogen Production Process Using Immobilized Anaerobic Sludge from Organic Solid Waste

    Directory of Open Access Journals (Sweden)

    Patrick T. Sekoai

    2016-12-01

    Full Text Available This study examined the potential of organic solid waste for biohydrogen production using immobilized anaerobic sludge. Biohydrogen was produced under batch mode at process conditions of 7.9, 30.3 °C and 90 h for pH, temperature and fermentation time, respectively. A maximum biohydrogen fraction of 48.67%, which corresponded to a biohydrogen yield of 215.39 mL H2/g Total Volatile Solids (TVS, was achieved. Therefore, the utilization of immobilized cells could pave the way for a large-scale biohydrogen production process.

  7. Boosting dark fermentation with co-cultures of extreme thermophiles for biohythane production from garden waste.

    Science.gov (United States)

    Abreu, Angela A; Tavares, Fábio; Alves, Maria Madalena; Pereira, Maria Alcina

    2016-11-01

    Proof of principle of biohythane and potential energy production from garden waste (GW) is demonstrated in this study in a two-step process coupling dark fermentation and anaerobic digestion. The synergistic effect of using co-cultures of extreme thermophiles to intensify biohydrogen dark fermentation is demonstrated using xylose, cellobiose and GW. Co-culture of Caldicellulosiruptor saccharolyticus and Thermotoga maritima showed higher hydrogen production yields from xylose (2.7±0.1molmol(-1) total sugar) and cellobiose (4.8±0.3molmol(-1) total sugar) compared to individual cultures. Co-culture of extreme thermophiles C. saccharolyticus and Caldicellulosiruptor bescii increased synergistically the hydrogen production yield from GW (98.3±6.9Lkg(-1) (VS)) compared to individual cultures and co-culture of T. maritima and C. saccharolyticus. The biochemical methane potential of the fermentation end-products was 322±10Lkg(-1) (CODt). Biohythane, a biogas enriched with 15% hydrogen could be obtained from GW, yielding a potential energy generation of 22.2MJkg(-1) (VS). Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Biohydrogen Production from Glycerol using Thermotoga spp

    NARCIS (Netherlands)

    Maru, B.T.; Bielen, A.A.M.; Kengen, S.W.M.; Constantini, M.; Medina, F.

    2012-01-01

    Given the highly reduced state of carbon in glycerol and its availability as a substantial byproduct of biodiesel production, glycerol is of special interest for sustainable biofuel production. Glycerol was used as a substrate for biohydrogen production using the hyperthermophilic bacterium,

  9. CFD optimization of continuous stirred-tank (CSTR) reactor for biohydrogen production.

    Science.gov (United States)

    Ding, Jie; Wang, Xu; Zhou, Xue-Fei; Ren, Nan-Qi; Guo, Wan-Qian

    2010-09-01

    There has been little work on the optimal configuration of biohydrogen production reactors. This paper describes three-dimensional computational fluid dynamics (CFD) simulations of gas-liquid flow in a laboratory-scale continuous stirred-tank reactor used for biohydrogen production. To evaluate the role of hydrodynamics in reactor design and optimize the reactor configuration, an optimized impeller design has been constructed and validated with CFD simulations of the normal and optimized impeller over a range of speeds and the numerical results were also validated by examination of residence time distribution. By integrating the CFD simulation with an ethanol-type fermentation process experiment, it was shown that impellers with different type and speed generated different flow patterns, and hence offered different efficiencies for biohydrogen production. The hydrodynamic behavior of the optimized impeller at speeds between 50 and 70 rev/min is most suited for economical biohydrogen production. Copyright 2010 Elsevier Ltd. All rights reserved.

  10. Continuous biohydrogen production from waste bread by anaerobic sludge.

    Science.gov (United States)

    Han, Wei; Huang, Jingang; Zhao, Hongting; Li, Yongfeng

    2016-07-01

    In this study, continuous biohydrogen production from waste bread by anaerobic sludge was performed. The waste bread was first hydrolyzed by the crude enzymes which were generated by Aspergillus awamori and Aspergillus oryzae via solid-state fermentation. It was observed that 49.78g/L glucose and 284.12mg/L free amino nitrogen could be produced with waste bread mass ratio of 15% (w/v). The waste bread hydrolysate was then used for biohydrogen production by anaerobic sludge in a continuous stirred tank reactor (CSTR). The optimal hydrogen production rate of 7.4L/(Ld) was achieved at chemical oxygen demand (COD) of 6000mg/L. According to the results obtained from this study, 1g waste bread could generate 0.332g glucose which could be further utilized to produce 109.5mL hydrogen. This is the first study which reports continuous biohydrogen production from waste bread by anaerobic sludge. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Bioelectrochemical Systems for Indirect Biohydrogen Production

    KAUST Repository

    Regan, John M.; Yan, Hengjing

    2014-01-01

    by exoelectrogens at the anode. As an indirect approach to biohydrogen production, these systems are not subject to the hydrogen yield constraints of fermentative processes and have been proven to work with virtually any biodegradable organic substrate

  12. Improvement of anaerobic bio-hydrogen gas production from organic sludge waste

    International Nuclear Information System (INIS)

    Lee, S.; Lee, Y. H.

    2009-01-01

    Microbial hydrogen gas production from organic matters stands out as one of the most promising alternatives for sustainable green energy production. Based on the literature review, investigation of anaerobic bio-hydrogen gas production from organic sludge waste using a mixed culture has been very limited. The objective of this study was to assess the anaerobic bio-hydrogen gas production from organic sludge waste under various conditions. (Author)

  13. Bioelectrochemical Systems for Indirect Biohydrogen Production

    KAUST Repository

    Regan, John M.

    2014-01-01

    Bioelectrochemical systems involve the use of exoelectrogenic (i.e., anode-reducing) microbes to produce current in conjunction with the oxidation of reduced compounds. This current can be used directly for power in a microbial fuel cell, but there are alternate uses of this current. One such alternative is the production of hydrogen in a microbial electrolysis cell (MEC), which accomplishes cathodic proton reduction with a slight applied potential by exploiting the low redox potential produced by exoelectrogens at the anode. As an indirect approach to biohydrogen production, these systems are not subject to the hydrogen yield constraints of fermentative processes and have been proven to work with virtually any biodegradable organic substrate. With continued advancements in reactor design to reduce the system internal resistance, increase the specific surface area for anode biofilm development, and decrease the material costs, MECs may emerge as a viable alternative technology for biohydrogen production. Moreover, these systems can also incorporate other value-added functionalities for applications in waste treatment, desalination, and bioremediation.

  14. A comprehensive and quantitative review of dark fermentative biohydrogen production

    Directory of Open Access Journals (Sweden)

    Rittmann Simon

    2012-08-01

    Full Text Available Abstract Biohydrogen production (BHP can be achieved by direct or indirect biophotolysis, photo-fermentation and dark fermentation, whereof only the latter does not require the input of light energy. Our motivation to compile this review was to quantify and comprehensively report strains and process performance of dark fermentative BHP. This review summarizes the work done on pure and defined co-culture dark fermentative BHP since the year 1901. Qualitative growth characteristics and quantitative normalized results of H2 production for more than 2000 conditions are presented in a normalized and therefore comparable format to the scientific community. Statistically based evidence shows that thermophilic strains comprise high substrate conversion efficiency, but mesophilic strains achieve high volumetric productivity. Moreover, microbes of Thermoanaerobacterales (Family III have to be preferred when aiming to achieve high substrate conversion efficiency in comparison to the families Clostridiaceae and Enterobacteriaceae. The limited number of results available on dark fermentative BHP from fed-batch cultivations indicates the yet underestimated potential of this bioprocessing application. A Design of Experiments strategy should be preferred for efficient bioprocess development and optimization of BHP aiming at improving medium, cultivation conditions and revealing inhibitory effects. This will enable comparing and optimizing strains and processes independent of initial conditions and scale.

  15. Thermophilic fermentative hydrogen production by the newly isolated Thermoanaerobacterium thermosaccharolyticum PSU-2

    DEFF Research Database (Denmark)

    O-Thong, Sompong; Prasertsan, P.; Karakashev, Dimitar Borisov

    2008-01-01

    fermentation (24 h) and stopped at pH 4.5 due to the accumulation of organic acids. The maximum H(2) production yield and rate at sucrose concentration of 20 gl(-1), pH 6.25 and temperature 60 degrees C were 2.53 mol H(2) mol(-1) hexose and 12.12 mmol H(2) l(-1) h(-1), respectively. Organic nitrogen amended......A thermophilic H(2)-producing bacterial strain was isolated from a biohydrogen reactor fed with palm oil mill effluent (POME) and identified as Thermoanaerobacterium thermosaccharolyticum using 16S rRNA gene analysis. The isolated bacterium, designated as T thermosaccharolyticum PSU-2, showed...... a high yield and production rate of H(2). Temperature optimum, pH optimum and substrate utilization for H(2) production were investigated in batch conditions. All of tested substrate was utilized for H(2) production, while sucrose, xylose and starch were the preferred substrates. The strain produced H(2...

  16. Biohydrogen production as a potential energy fuel in South Africa

    Directory of Open Access Journals (Sweden)

    P.T. Sekoai

    2015-06-01

    Full Text Available Biohydrogen production has captured increasing global attention due to it social, economic and environmental benefits. Over the past few years, energy demands have been growing significantly in South Africa due to rapid economic and population growth. The South African parastatal power supplier i.e. Electricity Supply Commission (ESKOM has been unable to meet the country’s escalating energy needs. As a result, there have been widespread and persistent power cuts throughout the country. This prompts an urgent need for exploration and implementation of clean and sustainable energy fuels like biohydrogen production in order to address this crisis. Therefore, this paper discusses the current global energy challenges in relation to South Africa’s problems. It then examines the feasibility of using biohydrogen production as a potential energy fuel in South Africa. Finally, it reviews the hydrogen-infrastructure development plans in the country.

  17. Critical assessment of anaerobic processes for continuous biohydrogen production from organic wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Show, Kuan-Yeow [Faculty of Engineering and Green Technology, University Tunku Abdul Rahman, Jalan University, Bandar Barat, 31900 Kampar, Perak (Malaysia); Zhang, Zhen-Peng [Beijing Enterprises Water Group Limited, BLK 25, No. 3 Minzhuang Road, Beijing 100195 (China); Tay, Joo-Hwa [School of Civil and Environmental Engineering, Nanyang Technological University, Nanyang Avenue (Singapore); Liang, David Tee [Institute of Environmental Science and Engineering, Nanyang Technological University (Singapore); Lee, Duu-Jong [Department of Chemical Engineering, National Taiwan University, Taipei (China); Ren, Nanqi; Wang, Aijie [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China)

    2010-12-15

    Production of biohydrogen using dark fermentation has received much attention owing to the fact that hydrogen can be generated from renewable organics including waste materials. The key to successful application of anaerobic fermentation is to uncouple the liquid retention time and the biomass retention time in the reactor system. Various reactor designs based on biomass retention within the reactor system have been developed. This paper presents our research work on bioreactor designs and operation for biohydrogen production. Comparisons between immobilized-cell systems and suspended-cell systems based on biomass growth in the forms of granule, biofilm and flocs were made. Reactor configurations including column- and tank-based reactors were also assessed. Experimental results indicated that formation of granules or biofilms substantially enhanced biomass retention which was found to be proportional to the hydrogen production rate. Rapid hydrogen-producing culture growth and high organic loading rate might limit the application of biofilm biohydrogen production, since excessive growth of fermentative biomass would result in washout of support carrier. It follows that column-based granular sludge process is a preferred choice of process for continuous biohydrogen production from organic wastewater, indicating maximum hydrogen yield of 1.7 mol-H{sub 2}/mol-glucose and hydrogen production rate of 6.8 L-H{sub 2}/L-reactor h. (author)

  18. Bio-hydrolysis and bio-hydrogen production from food waste by thermophilic and hyperthermophilic anaerobic process.

    Science.gov (United States)

    Algapani, Dalal E; Qiao, Wei; Su, Min; di Pumpo, Francesca; Wandera, Simon M; Adani, Fabrizio; Dong, Renjie

    2016-09-01

    High-temperature pretreatment plays a key role in the anaerobic digestion of food waste (FW). However, the suitable temperature is not yet determined. In this work, a long-term experiment was conducted to compare hydrolysis, acidogenesis, acetogenesis, and hydrogen production at 55°C and 70°C, using real FW in CSTR reactors. The results obtained indicated that acidification was the rate-limiting step at both temperatures with similar process kinetics characterizations. However, the thermophilic pretreatment was more advantageous than the hyperthermophilic with suspended solids solubilization of 47.7% and 29.5% and total VFA vs. soluble COD ratio of 15.2% and 4.9%, for thermophilic and hyperthermophilic treatment, respectively, with a hydrolytic reaction time (HRT) of 10days and an OLR of 14kgCOD/m(3)d. Moreover, stable hydrogen yield (70.7ml-H2/gVSin) and content in off gas (58.6%) was achieved at HRT 5days, pH 5.5, and temperature of 55°C, as opposed to 70°C. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Comparative techno-economic analysis of biohydrogen production via bio-oil gasification and bio-oil reforming

    International Nuclear Information System (INIS)

    Zhang, Yanan; Brown, Tristan R.; Hu, Guiping; Brown, Robert C.

    2013-01-01

    This paper evaluates the economic feasibility of biohydrogen production via two bio-oil processing pathways: bio-oil gasification and bio-oil reforming. Both pathways employ fast pyrolysis to produce bio-oil from biomass stock. The two pathways are modeled using Aspen Plus ® for a 2000 t d −1 facility. Equipment sizing and cost calculations are based on Aspen Economic Evaluation® software. Biohydrogen production capacity at the facility is 147 t d −1 for the bio-oil gasification pathway and 160 t d −1 for the bio-oil reforming pathway. The biomass-to-fuel energy efficiencies are 47% and 84% for the bio-oil gasification and bio-oil reforming pathways, respectively. Total capital investment (TCI) is 435 million dollars for the bio-oil gasification pathway and is 333 million dollars for the bio-oil reforming pathway. Internal rates of return (IRR) are 8.4% and 18.6% for facilities employing the bio-oil gasification and bio-oil reforming pathways, respectively. Sensitivity analysis demonstrates that biohydrogen price, biohydrogen yield, fixed capital investment (FCI), bio-oil yield, and biomass cost have the greatest impacts on facility IRR. Monte-Carlo analysis shows that bio-oil reforming is more economically attractive than bio-oil gasification for biohydrogen production. -- Highlights: ► Biohydrogen production via bio-oil reforming has higher energy efficiency compared to gasification. ► Hydrogen price, fixed capital cost, and feedstock cost most strongly affect IRR. ► Lower risk investment is biohydrogen production via bio-oil reforming

  20. Improved biohydrogen production and treatment of pulp and paper mill effluent through ultrasonication pretreatment of wastewater

    International Nuclear Information System (INIS)

    Hay, Jacqueline Xiao Wen; Wu, Ta Yeong; Juan, Joon Ching; Md Jahim, Jamaliah

    2015-01-01

    Highlights: • Ultrasonication facilitated the reuse of PPME in biohydrogen production. • Ultrasonication at an amplitude of 60% for 45 min produced the highest biohydrogen. • Ultrasonication increased the solubilization of PPME. • Higher net savings were obtained in pretreated PPME compared to raw PPME. - Abstract: Pulp and paper mill effluent (PPME), a rich cellulosic material, was found to have great potential for biohydrogen production through a photofermentation process. However, pretreatments were needed for degrading the complex structure of PPME before biohydrogen production. The aim of this study was to gain further insight into the effect of an ultrasonication process on PPME as a pretreatment method and on photofermentative biohydrogen production using Rhodobacter sphaeroides NCIMB. The ultrasonication amplitudes and times were varied between 30–90% and 15–60 min, respectively, and no dilution or nutrient supplementation was introduced during the biohydrogen production process. A higher biohydrogen yield, rate, light efficiency and COD removal efficiency were attained in conditions using ultrasonicated PPME. Among these different pretreatment conditions, PPME with ultrasonication pretreatment employing an amplitude of 60% and time of 45 min (A60:T45) gave the highest yield and rate of 5.77 mL H_2/mL medium and 0.077 mL H_2/mL h, respectively, while the raw PPME without ultrasonication showed a significantly lower yield and rate of 1.10 mL H_2/mL medium and 0.015 mL H_2/mL h, respectively. The results of this study demonstrated the potential of using ultrasonication as a pretreatment for PPME because the yield and rate of biohydrogen production were highly enhanced compared to the raw PPME. Economic analysis was also performed in this study, and in comparison with raw PPME, the highest net saving was $0.2132 for A60:T45.

  1. Bio-hydrogen production from hyacinth by anaerobic fermentation

    International Nuclear Information System (INIS)

    Cheng Jun; Zhou Junhu; Qi Feng; Xie Binfei; Cen Kefa

    2006-01-01

    The bio-hydrogen production from hyacinth by anaerobic fermentation of digested sludge is studied in this paper. The compositions of bio-gases and volatile fatty acids in fermentation liquids are determined on TRACE 2000 gas chromatography. It is found that the H 2 concentration in the biogas is 10%-20% and no CH 4 is detected. The bio-hydrogen production from hyacinth with the initial pH value of 5.5 is higher than that with the initial pH value of 4.5. The fermentation temperature of 55 C is better than that of 35 C, while the weight ratio of hyacinth to microorganism of 1:1 is better than that of 3:7. The highest hydrogen production of 122.3 mL/g is obtained when the initial pH value of fermentation solution is 5.5, the fermentation temperature is 55 C and the weight ratio of hyacinth to microorganism is 1:1. (authors)

  2. DEVELOPMENT OF A METHANE-FREE, CONTINUOUS BIOHYDROGEN PRODUCTION SYSTEM FROM PALM OIL MILL EFFLUENT (POME IN CSTR

    Directory of Open Access Journals (Sweden)

    MARIATUL FADZILLAH MANSOR

    2016-08-01

    Full Text Available This study aimed to develop the start-up experiment for producing biological hydrogen in 2 L continuous stirred tank reactor (CSTR from palm oil mill effluent (POME by the use of mixed culture sludge under non-sterile conditions. Besides using different source of starter culture, the effects of acid treated culture and various operating temperature from 35 °C to 55 °C were studied against the evolved gas in terms of volumetric H2 production rate (VHPR and soluble metabolite products (SMPs. The formation of methane was closely observed throughout the run. Within the studied temperature, VHPR was found as low as 0.71 L/L.d and ethanol was the main by-products (70-80% of total soluble metabolites. Attempts were made to produce biohydrogen without methane formation at higher thermophilic temperature (45-55 °C than the previous range. The average of 1.7 L H2 of 2 L working volume per day was produced at 55 oC with VHPR of 1.16 L/L.d. The results of soluble metabolites also are in agreement with the volatile fatty acids (VFAs which is higher than ethanol. Higher VFAs of 2269 mg/L was obtained with acetic acid being the main by-product. At this time methanogen has been deactivated and no methane was produced. From this study, it can be concluded that thermophilic environment may offer a better option in a way to eliminate methane from the biogas and at the same time improving hydrogen production rate as well.

  3. Evaluation of pretreatment methods on mixed inoculum for both batch and continuous thermophilic biohydrogen production from cassava stillage.

    Science.gov (United States)

    Luo, Gang; Xie, Li; Zou, Zhonghai; Wang, Wen; Zhou, Qi

    2010-02-01

    Anaerobic sludges, pretreated by chloroform, base, acid, heat and loading-shock, as well as untreated sludge were evaluated for their thermophilic fermentative hydrogen-producing characters from cassava stillage in both batch and continuous experiments. Results showed that the highest hydrogen production was obtained by untreated sludge and there were significant differences (pstillage.

  4. Biohydrogen production from organic waste and wastewater by dark fermentation. A promising module for renewable energy production

    Energy Technology Data Exchange (ETDEWEB)

    Krupp, M.

    2007-07-01

    Fossil fuels are limited and global warming due to increased CO{sub 2}-emissions may lead to worldwide environmental disasters. Therefore energy production from renewable sources is the most important task in the future. In the contribution under consideration, the author reports on biohydrogen production from organic waste and wastewater by dark fermentation.An engineered approach was chosen to get more information about the technical feasibility of a process which has been studied intensively in the current century. The developed test method represents a functional tool for determination of the biohydrogen production potential of a wide variety of different substances. The implementation of the 'glucose equivalent' for estimation of the biohydrogen potential of a certain substrate was a successfull approach. With this parameter, the biohydrogen potential could be evaluated properly without severe influence from the boundary conditions. Within the continuous test trials it could be found that continuous biohydrogen production in a 30 L-scale is feasible without costly regulation and control mechanisms. The further test series conducted in 30 L-scale gave important results for pilot plant design. One main result of the test runs is that it was shown that the control mechanisms could be reduced to a simple pH-regulation by addition of sodium hydroxide. Other parameters like organic loading rate (OLR) and hydraulic retention time (HRT) were clearly more important to ensure a stable continuous process. A HRT of 15-20 hours combined with an OLR of up to 14 kg VS/(d m{sup 3}) resulted in very high hydrogen yields of 2.14-2.56 mol H{sub 2}/mol glucose. Another important result for pilot plant construction was the necessity of input cooling. Due to ambient temperatures in the input vessels the substrate tests failed. Hydrolysis took place in the input vessels, not in the reactors. Gas upgrading by membrane systems was tested as well as post-methanisation or

  5. Biohydrogen production from enzymatic hydrolysis of food waste in batch and continuous systems

    OpenAIRE

    Wei Han; Yingting Yan; Yiwen Shi; Jingjing Gu; Junhong Tang; Hongting Zhao

    2016-01-01

    In this study, the feasibility of biohydrogen production from enzymatic hydrolysis of food waste was investigated. Food waste (solid-to-liquid ratio of 10%, w/v) was first hydrolyzed by commercial glucoamylase to release glucose (24.35?g/L) in the food waste hydrolysate. Then, the obtained food waste hydrolysate was used as substrate for biohydrogen production in the batch and continuous (continuous stirred tank reactor, CSTR) systems. It was observed that the maximum cumulative hydrogen prod...

  6. Biohydrogen Production from Pineapple Waste: Effect of Substrate Concentration and Acid Pretreatment

    Science.gov (United States)

    Cahyari, K.; Putri, A. M.; Oktaviani, E. D.; Hidayat, M. A.; Norajsha, J. D.

    2018-05-01

    Biohydrogen is the ultimate choice of energy carrier in future due to its superior qualities such as fewer greenhouse gases emission, high energy density (142 kJ/gram), and high energy conversion using a fuel cell. Production of biohydrogen from organic waste e.g. pineapple waste offers a simultaneous solution for renewable energy production and waste management. It is estimated that pineapple cultivation in Indonesia generated more than 1 million ton/year comprising of rotten pineapple fruit, leaves, and stems. Majority of this waste is dumped into landfill area without any treatments which lead to many environmental problems. This research was meant to investigate the utilization of pineapple waste i.e. peel and the core of pineapple fruit and leaves to produce biohydrogen through mesophilic dark fermentation (30°C, 1 atm, pH 5.0). Effect of dilute acid treatment and substrate concentration was particularly investigated in these experiments. Peel and core of pineapple waste were subjected to fermentation at 3 various substrate concentration i.e. 8.8, 17.6 and 26.4-gram VS/liter. Meanwhile, pineapple leaves were pretreated using dilute acid (H2SO4) at 0.2, 0.3 and 0.4 N and followed by dark fermentation. Results show that the highest yield of biohydrogen was obtained at a substrate concentration of 26.4-gram VS/liter both for peel and core of the waste. Pretreatment using dilute acid (H2SO4) 0.3 N might improve fermentation process with a higher yield at 0.8 ml/gram VS. Hydrogen percentage in biogas produced during fermentation process was in the range between 5 – 32% of volume ratio. In summary, it is possible to utilize pineapple waste for production of biohydrogen at an optimum substrate concentration of 26.4-gram VS/liter and acid pretreatment (H2SO4) of 0.3 N.

  7. Biohydrogen production from enzymatic hydrolysis of food waste in batch and continuous systems

    Science.gov (United States)

    Han, Wei; Yan, Yingting; Shi, Yiwen; Gu, Jingjing; Tang, Junhong; Zhao, Hongting

    2016-01-01

    In this study, the feasibility of biohydrogen production from enzymatic hydrolysis of food waste was investigated. Food waste (solid-to-liquid ratio of 10%, w/v) was first hydrolyzed by commercial glucoamylase to release glucose (24.35 g/L) in the food waste hydrolysate. Then, the obtained food waste hydrolysate was used as substrate for biohydrogen production in the batch and continuous (continuous stirred tank reactor, CSTR) systems. It was observed that the maximum cumulative hydrogen production of 5850 mL was achieved with a yield of 245.7 mL hydrogen/g glucose (1.97 mol hydrogen/mol glucose) in the batch system. In the continuous system, the effect of hydraulic retention time (HRT) on biohydrogen production from food waste hydrolysate was investigated. The optimal HRT obtained from this study was 6 h with the highest hydrogen production rate of 8.02 mmol/(h·L). Ethanol and acetate were the major soluble microbial products with low propionate production at all HRTs. Enzymatic hydrolysis of food waste could effectively accelerate hydrolysis speed, improve substrate utilization rate and increase hydrogen yield. PMID:27910937

  8. Biohydrogen production from a novel alkalophilic isolate Clostridium sp. IODB-O3.

    Science.gov (United States)

    Patel, Anil Kumar; Debroy, Arundhati; Sharma, Sandeep; Saini, Reetu; Mathur, Anshu; Gupta, Ravi; Tuli, Deepak Kumar

    2015-01-01

    Hydrogen producing bacteria IODB-O3 was isolated from sludge and identified as Clostridium sp. by 16S rDNA gene analysis. In this study, biohydrogen production process was developed using low-cost agro-waste. Maximum H2 was produced at 37°C and pH 8.5. Maximum H2 yield was obtained 2.54±0.2mol-H2/mol-reducing sugar from wheat straw pre-hydrolysate (WSPH) and 2.61±0.1mol-H2/mol-reducing sugar from pre-treated wheat straw enzymatic-hydrolysate (WSEH). The cumulative H2 production (ml/L), 3680±105 and 3270±100, H2 production rate (ml/L/h), 153±5 and 136±5, and specific H2 production (ml/g/h), 511±5 and 681±10 with WSPH and WSEH were obtained, respectively. Biomass pre-treatment via steam-explosion generates ample amount of WSPH which remains unutilized for bioethanol production due to non-availability of efficient C5-fermenting microorganisms. This study shows that Clostridium sp. IODB-O3 is capable of utilizing WSPH efficiently for biohydrogen production. This would lead to reduced economic constrain on the overall cellulosic ethanol process and also establish a sustainable biohydrogen production process. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Biohydrogen production and wastewater treatment from organic wastewater by anaerobic fermentation with UASB

    Science.gov (United States)

    Wang, Lu; Li, Yong-feng; Wang, Yi-xuan; Yang, Chuan-ping

    2010-11-01

    In order to discuss the ability of H2-production and wastewater treatment, an up-flow anaerobic sludge bed (UASB) using a synthesized substrate with brown sugar wastewater was conducted to investigate the hydrogen yield, hydrogen producing rate, fermentation type of biohydrogen production, and the chemical oxygen demand (COD) removal rate, respectively. The results show that when the biomass of inoculants was 22.5 g SSṡL-1 and the influent concentration, hydraulic retention time (HRT) and initial pH were within the ranges of 4000˜6000 mg CODṡL-1, 8 h and 5-5.5, respectively, and the biohydrogen producing reactor could work effectively. The maximum hydrogen production rate is 5.98 Lṡd-1. Simultaneously, the concentration of ethanol and acetic acid is around 80% of the aqueous terminal production in the system, which presents the typical ethanol type fermentation. pH is at the range of 4˜4.5 during the whole performing process, however, the removal rate of COD is just about 20%. Therefore, it's still needs further research to successfully achieve the biohydrogen production and wastewater treatment, simultaneously.

  10. Hydrogen Production by Thermophilic Fermentation

    NARCIS (Netherlands)

    Niel, van E.W.J.; Willquist, K.; Zeidan, A.A.; Vrije, de T.; Mars, A.E.; Claassen, P.A.M.

    2012-01-01

    Of the many ways hydrogen can be produced, this chapter focuses on biological hydrogen production by thermophilic bacteria and archaea in dark fermentations. The thermophiles are held as promising candidates for a cost-effective fermentation process, because of their relatively high yields and broad

  11. Enzymatic saccharification and fermentation of paper and pulp industry effluent for biohydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Lakshmidevi, Rajendran; Muthukumar, Karuppan [Department of Chemical Engineering, Alagappa College of Technology Campus, Anna University Chennai, Chennai 600 025 (India)

    2010-04-15

    Paper and pulp industry effluent was enzymatically hydrolysed using crude cellulase enzyme (0.8-2.2FPU/ml) obtained from Trichoderma reesei and from the hydrolysate biohydrogen was produced using Enterobacter aerogenes. The influence of temperature and incubation time on enzyme production was studied. The optimum temperature for the growth of T. reesei was found to be around 29 C. The enzyme activity of 2.5 FPU/ml was found to produce about 22 g/l of total sugars consisting mainly of glucose, xylose and arabinose. Relevant kinetic parameters with respect to sugars production were estimated using two fraction model. The enzymatic hydrolysate was used for the biohydrogen production using E. aerogenes. The growth data obtained for E. aerogenes were fitted well with Monod and Logistic equations. The maximum hydrogen yield of 2.03 mol H{sub 2}/mol sugar and specific hydrogen production rate of 225 mmol of H{sub 2}/g cell/h were obtained with an initial concentration of 22 g/l of total sugars. The colour and COD of effluent was also decreased significantly during the production of hydrogen. The results showed that the paper and pulp industry effluent can be used as a substrate for biohydrogen production. (author)

  12. Enhancement of Biohydrogen Production via pH Variation using Molasses as Feedstock in an Attached Growth System

    Science.gov (United States)

    Che Zuhar, C. N. S.; Lutpi, N. A.; Idris, N.; Wong, Y. S.; Tengku Izhar, T. N.

    2018-03-01

    In this study, mesophilic biohydrogen production by a mixed culture, obtained from a continuous anaerobic reactor treating molasses effluent from sugarcane bagasse, was improved by using granular activated carbon (GAC) as the carrier material. A series of batch fermentation were performed at 37°C by feeding the anaerobic sludge bacteria with molasses to determine the effect of initial pH in the range of 5.5 to 7.5, and the effect of repeated batch cultivation on biohydrogen production. The enrichment of granular activated carbon (GAC) immobilised cells from the repeated batch cultivation were used as immobilised seed culture to obtain the optimal initial pH. The cumulative hydrogen production results from the optimal pH were fitted into modified Gompertz equation in order to obtained the batch profile of biohydrogen production. The optimal hydrogen production was obtained at an initial pH of 5.5 with the maximum hydrogen production (Hm) was found to be 84.14 ml, and maximum hydrogen production rate (Rm) was 3.63 mL/h with hydrogen concentration of 759 ppm. The results showed that the granular activated carbon was successfully enhanced the biohydrogen production by stabilizing the pH and therefore could be used as a carrier material for fermentative hydrogen production using industrial effluent.

  13. Enhancement of Biohydrogen Production via pH Variation using Molasses as Feedstock in an Attached Growth System

    Directory of Open Access Journals (Sweden)

    Che Zuhar C.N.S.

    2018-01-01

    Full Text Available In this study, mesophilic biohydrogen production by a mixed culture, obtained from a continuous anaerobic reactor treating molasses effluent from sugarcane bagasse, was improved by using granular activated carbon (GAC as the carrier material. A series of batch fermentation were performed at 37°C by feeding the anaerobic sludge bacteria with molasses to determine the effect of initial pH in the range of 5.5 to 7.5, and the effect of repeated batch cultivation on biohydrogen production. The enrichment of granular activated carbon (GAC immobilised cells from the repeated batch cultivation were used as immobilised seed culture to obtain the optimal initial pH. The cumulative hydrogen production results from the optimal pH were fitted into modified Gompertz equation in order to obtained the batch profile of biohydrogen production. The optimal hydrogen production was obtained at an initial pH of 5.5 with the maximum hydrogen production (Hm was found to be 84.14 ml, and maximum hydrogen production rate (Rm was 3.63 mL/h with hydrogen concentration of 759 ppm. The results showed that the granular activated carbon was successfully enhanced the biohydrogen production by stabilizing the pH and therefore could be used as a carrier material for fermentative hydrogen production using industrial effluent.

  14. Biohydrogen and methane production by co-digestion of cassava stillage and excess sludge under thermophilic condition.

    Science.gov (United States)

    Wang, Wen; Xie, Li; Chen, Jinrong; Luo, Gang; Zhou, Qi

    2011-02-01

    Thermophilic anaerobic hydrogen and methane production by co-digestion of cassava stillage (CS) and excess sludge (ES) was investigated in this study. The improved hydrogen and subsequent methane production were observed by co-digestion of CS with certain amount of ES in batch experiments. Compared with one phase anaerobic digestion, two phase anaerobic digestion offered an attractive alternative with more abundant biogas production and energy yield, e.g., the total energy yield in two phase obtained at VS(CS)/VS(ES) of 3:1 was 25% higher than the value of one phase. Results from continuous experiments further demonstrated that VS(CS)/VS(ES) of 3:1 was optimal for hydrogen production with the highest hydrogen yield of 74 mL/gtotal VS added, the balanced nutrient condition with C/N ratio of 1.5 g carbohydrate-COD/gprotein-COD or 11.9 g C/gN might be the main reason for such enhancement. VS(CS)/VS(ES) of 3:1 was also optimal for continuous methane production considering the higher methane yield of 350 mL/gtotal VS added and the lower propionate concentration in the effluent. Copyright © 2010 Elsevier Ltd. All rights reserved.

  15. Biohydrogen from thermophilic co-fermentation of swine manure with fruit and vegetable waste: maximizing stable production without pH control.

    Science.gov (United States)

    Tenca, A; Schievano, A; Perazzolo, F; Adani, F; Oberti, R

    2011-09-01

    Hydrogen production by dark fermentation may suffer of inhibition or instability due to pH deviations from optimality. The co-fermentation of promptly degradable feedstock with alkali-rich materials, such as livestock wastes, may represent a feasible and easy to implement approach to avoid external adjustments of pH. Experiments were designed to investigate the effect of the mixing ratio of fruit-vegetable waste with swine manure with the aim of maximizing biohydrogen production while obtaining process stability through the endogenous alkalinity of manure. Fruit-vegetable/swine manure ratio of 35/65 and HRT of 2d resulted to give the highest production rate of 3.27 ± 0.51 L(H2)L(-1)d(-1), with a corresponding hydrogen yield of 126 ± 22 mL(H2)g(-1)(VS-added) and H2 content in the biogas of 42 ± 5%. At these operating conditions the process exhibited also one of the highest measured stability, with daily productions deviating for less than 14% from the average. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Novel fungal consortium pretreatment of waste oat straw to enhance economic and efficient biohydrogen production

    Directory of Open Access Journals (Sweden)

    Lirong Zhou

    2016-12-01

    Full Text Available Bio-pretreatment using a fungal consortium to enhance the efficiency of lignocellulosic biohydrogen production was explored.  A fungal consortium comprised of T. viride and P. chrysosporium as microbial inoculum was compared with untreated and single-species-inoculated samples. Fungal bio-pretreatment was carried out at atmospheric conditions with limited external energy input.  The effectiveness of the pretreatment is evaluated according to its lignin removal and digestibility. Enhancement of biohydrogen production is observed through scanning electron microscopy (SEM analysis. Fungal consortium pretreatment effectively degraded oat straw lignin (by >47% in 7 days leading to decomposition of cell-wall structure as revealed in SEM images, increasing biohydrogen yield. The hydrogen produced from the fungal consortium pretreated straw increased by 165% 6 days later, and was more than produced from either a single fungi species of T. viride or P. chrysosponium pretreated straw (94% and 106%, respectively. No inhibitory effect on hydrogen production was observed.

  17. Improving photofermentative biohydrogen production by using intermittent ultrasonication and combined industrial effluents from palm oil, pulp and paper mills

    International Nuclear Information System (INIS)

    Budiman, Pretty Mori; Wu, Ta Yeong; Ramanan, Ramakrishnan Nagasundara; Md Jahim, Jamaliah

    2017-01-01

    Highlights: • Intermittent ultrasonication onto broth improved biohydrogen production. • A20T10 treatment produced 14.438 mL H_2/mL_m_e_d_i_u_m with 7.412% light efficiency. • Excessive ultrasonication (>306.1 J/mL) inhibited biohydrogen production. - Abstract: An ultrasonication technique was applied intermittently onto photofermentation broth during the first six hours of photofermentation to improve biohydrogen production by using Rhodobacter sphaeroides NCIMB8253. In this research, photofermentation broth consisted of a combination of palm oil (25%, v/v), pulp and paper (75%, v/v) mill effluents as well as liquid inoculum. The effects of amplitude (10, 20 and 30%, A) and ultrasonication duration (5, 10 and 15 min, T) were investigated in terms of their influences on photofermentative biohydrogen yield and total chemical oxygen demand (COD_t_o_t_a_l) removal. The recommended ultrasonication parameters were found at the middle range of amplitude and duration (A20T10). Using A20T10 intermittent treatment, the production of biohydrogen could be maximized up to 14.438 mL H_2/mL_m_e_d_i_u_m with a COD_t_o_t_a_l removal and light efficiency of 52.2% and 7.412%, respectively. By comparing the treatment without intermittent ultrasonication, an increase of biohydrogen yield by 44.6% was achieved in A20T10 treatment. A total energy input of 306.1 J/mL (A20T10 treatment) was supplied to improve substrate consumption and light distribution during the photofermentation, which led to the increase of biohydrogen yield.

  18. Bio-hydrogen production from molasses by anaerobic fermentation in continuous stirred tank reactor

    Science.gov (United States)

    Han, Wei; Li, Yong-feng; Chen, Hong; Deng, Jie-xuan; Yang, Chuan-ping

    2010-11-01

    A study of bio-hydrogen production was performed in a continuous flow anaerobic fermentation reactor (with an available volume of 5.4 L). The continuous stirred tank reactor (CSTR) for bio-hydrogen production was operated under the organic loading rates (OLR) of 8-32 kg COD/m3 reactor/d (COD: chemical oxygen demand) with molasses as the substrate. The maximum hydrogen production yield of 8.19 L/d was obtained in the reactor with the OLR increased from 8 kg COD/m3 reactor/d to 24 kg COD/m3 d. However, the hydrogen production and volatile fatty acids (VFAs) drastically decreased at an OLR of 32 kg COD/m3 reactor/d. Ethanoi, acetic, butyric and propionic were the main liquid fermentation products with the percentages of 31%, 24%, 20% and 18%, which formed the mixed-type fermentation.

  19. Biohydrogen production from rotten orange with immobilized mixed culture: Effect of immobilization media for various composition of substrates

    Energy Technology Data Exchange (ETDEWEB)

    Damayanti, Astrilia, E-mail: liasholehasd@gmail.com [Department of Chemical Engineering, Faculty of Engineering, Semarang State University, E1 Building, 2nd floor, Kampus Sekaran, Gunungpati, Semarang 50229 (Indonesia); Department of Chemical Engineering, Faculty of Engineering, Gadjah Mada University, Jl. Grafika No. 2, Kampus UGM, Yogyakarta 55281 (Indonesia); Sarto,; Syamsiah, Siti; Sediawan, Wahyudi B. [Department of Chemical Engineering, Faculty of Engineering, Gadjah Mada University, Jl. Grafika No. 2, Kampus UGM, Yogyakarta 55281 (Indonesia)

    2015-12-29

    Enriched–immobilized mixed culture was utilized to produce biohydrogen in mesophilic condition under anaerobic condition using rotten orange as substrate. The process was conducted in batch reactors for 100 hours. Microbial cultures from three different sources were subject to a series of enrichment and immobilized in two different types of media, i.e. calcium alginate (CA, 2%) and mixture of alginate and activated carbon (CAC, 1:1). The performance of immobilized culture in each media was tested for biohydrogen production using four different substrate compositions, namely orange meat (OM), orange meat added with peel (OMP), orange meat added with limonene (OML), and mixture of orange meat and peel added with limonene (OMPL). The results show that, with immobilized culture in CA, the variation of substrate composition gave significant effect on the production of biohydrogen. The highest production of biohydrogen was detected for substrate containing only orange meet, i.e. 2.5%, which was about 3-5 times higher than biohydrogen production from other compositions of substrate. The use of immobilized culture in CAC in general has increased the hydrogen production by 2-7 times depending on the composition of substrate, i.e. 5.4%, 4.8%, 5.1%, and 4.4% for OM, OMP, OML, and OMPL, respectively. The addition of activated carbon has eliminated the effect of inhibitory compounds in the substrate. The major soluble metabolites were acetic acid, propionic acid, and butyric acid.

  20. Biohydrogen production from rotten orange with immobilized mixed culture: Effect of immobilization media for various composition of substrates

    Science.gov (United States)

    Damayanti, Astrilia; Sarto, Syamsiah, Siti; Sediawan, Wahyudi B.

    2015-12-01

    Enriched-immobilized mixed culture was utilized to produce biohydrogen in mesophilic condition under anaerobic condition using rotten orange as substrate. The process was conducted in batch reactors for 100 hours. Microbial cultures from three different sources were subject to a series of enrichment and immobilized in two different types of media, i.e. calcium alginate (CA, 2%) and mixture of alginate and activated carbon (CAC, 1:1). The performance of immobilized culture in each media was tested for biohydrogen production using four different substrate compositions, namely orange meat (OM), orange meat added with peel (OMP), orange meat added with limonene (OML), and mixture of orange meat and peel added with limonene (OMPL). The results show that, with immobilized culture in CA, the variation of substrate composition gave significant effect on the production of biohydrogen. The highest production of biohydrogen was detected for substrate containing only orange meet, i.e. 2.5%, which was about 3-5 times higher than biohydrogen production from other compositions of substrate. The use of immobilized culture in CAC in general has increased the hydrogen production by 2-7 times depending on the composition of substrate, i.e. 5.4%, 4.8%, 5.1%, and 4.4% for OM, OMP, OML, and OMPL, respectively. The addition of activated carbon has eliminated the effect of inhibitory compounds in the substrate. The major soluble metabolites were acetic acid, propionic acid, and butyric acid.

  1. Biohydrogen production from rotten orange with immobilized mixed culture: Effect of immobilization media for various composition of substrates

    International Nuclear Information System (INIS)

    Damayanti, Astrilia; Sarto,; Syamsiah, Siti; Sediawan, Wahyudi B.

    2015-01-01

    Enriched–immobilized mixed culture was utilized to produce biohydrogen in mesophilic condition under anaerobic condition using rotten orange as substrate. The process was conducted in batch reactors for 100 hours. Microbial cultures from three different sources were subject to a series of enrichment and immobilized in two different types of media, i.e. calcium alginate (CA, 2%) and mixture of alginate and activated carbon (CAC, 1:1). The performance of immobilized culture in each media was tested for biohydrogen production using four different substrate compositions, namely orange meat (OM), orange meat added with peel (OMP), orange meat added with limonene (OML), and mixture of orange meat and peel added with limonene (OMPL). The results show that, with immobilized culture in CA, the variation of substrate composition gave significant effect on the production of biohydrogen. The highest production of biohydrogen was detected for substrate containing only orange meet, i.e. 2.5%, which was about 3-5 times higher than biohydrogen production from other compositions of substrate. The use of immobilized culture in CAC in general has increased the hydrogen production by 2-7 times depending on the composition of substrate, i.e. 5.4%, 4.8%, 5.1%, and 4.4% for OM, OMP, OML, and OMPL, respectively. The addition of activated carbon has eliminated the effect of inhibitory compounds in the substrate. The major soluble metabolites were acetic acid, propionic acid, and butyric acid

  2. Organic loading rate impact on biohydrogen production and microbial communities at anaerobic fluidized thermophilic bed reactors treating sugarcane stillage.

    Science.gov (United States)

    Santos, Samantha Christine; Rosa, Paula Rúbia Ferreira; Sakamoto, Isabel Kimiko; Varesche, Maria Bernadete Amâncio; Silva, Edson Luiz

    2014-05-01

    This study aimed to evaluate the effect of high organic loading rates (OLR) (60.0-480.00 kg COD m(-3)d(-1)) on biohydrogen production at 55°C, from sugarcane stillage for 15,000 and 20,000 mg CODL(-1), in two anaerobic fluidized bed reactors (AFBR1 and AFBR2). It was obtained, for H2 yield and content, a decreasing trend by increasing the OLR. The maximum H2 yield was observed in AFBR1 (2.23 mmol g COD added(-1)). The volumetric H2 production was proportionally related to the applied hydraulic retention time (HRT) of 6, 4, 2 and 1h and verified in AFBR1 the highest value (1.49 L H2 h(-1)L(-1)). Among the organic acids obtained, there was a predominance of lactic acid (7.5-22.5%) and butyric acid (9.4-23.8%). The microbial population was set with hydrogen-producing fermenters (Megasphaera sp.) and other organisms (Lactobacillus sp.). Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Biohydrogen production from desugared molasses (DM) using thermophilic mixed cultures immobilized on heat treated anaerobic sludge granules

    DEFF Research Database (Denmark)

    Kongjan, Prawit; O-Thong, Sompong; Angelidaki, Irini

    2011-01-01

    Hydrogen production from desugared molasses (DM) was investigated in both batch and continuous reactors using thermophilic mixed cultures enriched from digested manure by load shock (loading with DM concentration of 50.1 g-sugar/L) to suppress methanogens. H2 gas, free of methane, was produced......) and Thermoanaerobacterium thermosaccharolyticum with a relative abundance of 36%, 27%, and 10% of total microorganisms, respectively. This study shows that hydrogen production could be efficiently facilitated by using anaerobic granules as a carrier, where microbes from mixed culture enriched in the DM batch cultivation....... The enriched hydrogen producing mixed culture achieved from the 16.7 g-sugars/L DM batch cultivation was immobilized on heat treated anaerobic sludge granules in an up-flow anaerobic sludge blanket (UASB) reactor. The UASB reactor, operated at a hydraulic retention time (HRT) of 24 h fed with 16.7 g...

  4. Thermophilic, lignocellulolytic bacteria for ethanol production: current state and perspectives

    DEFF Research Database (Denmark)

    Chang, Tinghong; Yao, Shuo

    2011-01-01

    of cellulolytic and saccharolytic thermophilic bacteria for lignocellulosic ethanol production because of their unique properties. First of all, thermophilic bacteria possess unique cellulolytic and hemicellulolytic systems and are considered as potential sources of highly active and thermostable enzymes...... for efficient biomass hydrolysis. Secondly, thermophilic bacteria ferment a broad range of carbohydrates into ethanol, and some of them display potential for ethanologenic fermentation at high yield. Thirdly, the establishment of the genetic tools for thermophilic bacteria has allowed metabolic engineering......, in particular with emphasis on improving ethanol yield, and this facilitates their employment for ethanol production. Finally, different processes for second-generation ethanol production based on thermophilic bacteria have been proposed with the aim to achieve cost-competitive processes. However, thermophilic...

  5. Biohydrogen production from co-digestion of high carbohydrate containing food waste and combined primary and secondary sewage sludge

    International Nuclear Information System (INIS)

    Arain, M.; Sahito, R.

    2018-01-01

    In this paper, FW (Food Waste) and SS (Sewage Sludge) were co-digested for biohydrogen production. After characterization both FW and SS were found as better option for biohydrogen production. FW was rich in carbohydrate containing specially rice, which was added as more than 50% and easily hydrolyzable waste. FW is considered as an auxiliary substrate for biohydrogen production and high availability of carbohydrate in FW makes it an important substrate for the production of biohydrogen. On the contrary, SS was rich in protein and has a high pH buffering capacity, which makes it appropriate for codigestion. Adequate supplementation of inorganic salts, the addition of hydrogen producing inoculums, protein enrichment and pH buffering capacity of SS and carbohydrate content in FW increases the hydrogen production potential. Various experiments were performed by considering different mixing ratios like 90:10, 80:20, 70:30, 60:40 and 50:50 of FW and SS. The 50:50 and 90:10 mixing ratio of FW and SS were found as best among all other co-digested ratios. The maximum specific hydrogen yield 106.7 mL/gVS added was obtained at a waste composition of 50:50 followed by 92.35 mL/gVS added from 90:10 of FW to SS. The optimum pH and temperature for operating this process were in the range of 5.5-6.5 and 35°C. The production of clean energy and waste utilization in anaerobic co-digestion process makes biohydrogen generation a promising and novel approach to fulfilling the increasing energy needs as a substitute for fossil fuels. (author)

  6. The organic agricultural waste as a basic source of biohydrogen production

    Science.gov (United States)

    Sriwuryandari, Lies; Priantoro, E. Agung; Sintawardani, Neni; Astuti, J. Tri; Nilawati, Dewi; Putri, A. Mauliva Hada; Mamat, Sentana, Suharwadji; Sembiring, T.

    2016-02-01

    Biohydrogen production research was carried out using raw materials of agricultural organic waste that was obtained from markets around the Bandung city. The organic part, which consisted of agricultural waste material, mainly fruit and vegetable waste, was crushed and milled using blender. The sludge that produced from milling process was then used as a substrate for mixed culture microorganism as a raw material to produce biohydrogen. As much as 1.2 kg.day-1 of sludge (4% of total solid) was fed into bioreactor that had a capacity of 30L. Experiment was done under anaerobic fermentation using bacteria mixture culture that maintained at pH in the range of 5.6-6.5 and temperature of 25-30oC on semi-continuous mode. Parameters of analysis include pH, temperature, total solid (TS), organic total solid (OTS), total gas production, and hydrogen gas production. The results showed that from 4% of substrate resulted 897.86 L of total gas, which contained 660.74 L (73.59%) of hydrogen gas. The rate of hydrogen production in this study was 11,063 mol.L-1.h-1.

  7. Bioprospecting thermophiles for cellulase production: a review.

    Science.gov (United States)

    Acharya, Somen; Chaudhary, Anita

    2012-07-01

    Most of the potential bioprospecting is currently related to the study of the extremophiles and their potential use in industrial processes. Recently microbial cellulases find applications in various industries and constitute a major group of industrial enzymes. Considerable amount of work has been done on microbial cellulases, especially with resurgence of interest in biomass ethanol production employing cellulases and use of cellulases in textile and paper industry. Most efficient method of lignocellulosic biomass hydrolysis is through enzymatic saccharification using cellulases. Significant information has also been gained about the physiology of thermophilic cellulases producers and process development for enzyme production and biomass saccharification. The review discusses the current knowledge on cellulase producing thermophilic microorganisms, their physiological adaptations and control of cellulase gene expression. It discusses the industrial applications of thermophilic cellulases, their cost of production and challenges in cellulase research especially in the area of improving process economics of enzyme production.

  8. Bio-hydrogen production from glycerol by a strain of Enterobacter aerogenes

    Energy Technology Data Exchange (ETDEWEB)

    Marques, P.A.S.S; Bartolomeu, M.L.; Tome, M.M.; Rosa, M.F. [INETI, Unit of Biomass/Renewable Energy Department, Estrada do Paco do Lumiar, 22, 1649-038 Lisboa (Portugal)

    2008-07-01

    The goal of this work was to evaluate the H2 production from glycerol-containing byproducts obtained from biodiesel industrial production, using Enterobacter aerogenes ATCC 13048 Sputum. H2 production using as substrate pure glycerol and glycerol-containing biodiesel byproducts was compared. The effect of parameters such as initial substrate concentration and sodium chloride addition on the bio-hydrogen production efficiency was also investigated. The results showed that using 10 g/L of pure glycerol or biodiesel residues, containing the same concentration of glycerol as substrate, lead to similar bio-hydrogen productions (3.46 LH2/L and 3.28 LH2/L fermentation medium, respectively). This indicates that the performance of the E. aerogenes strain used was not influenced by the presence of other components than glycerol in biodiesel residues, at least for the tested waste concentration range. When sodium chloride was added to the fermentation medium with pure 10 g/L glycerol, H2 production was not affected (3.34 LH2/L fermentation medium), showing that metabolism of the E. aerogenes strain was not inhibited by this biodiesel waste component up to 4 g/L chloride concentration. Biodiesel residues used without sterilization provided a higher H2 production (1.03 L) than the ones submitted to previous sterilization in autoclave (0.89 L).

  9. Bioprospecting thermophiles for cellulase production: a review

    Directory of Open Access Journals (Sweden)

    Somen Acharya

    2012-09-01

    Full Text Available Most of the potential bioprospecting is currently related to the study of the extremophiles and their potential use in industrial processes. Recently microbial cellulases find applications in various industries and constitute a major group of industrial enzymes. Considerable amount of work has been done on microbial cellulases, especially with resurgence of interest in biomass ethanol production employing cellulases and use of cellulases in textile and paper industry. Most efficient method of lignocellulosic biomass hydrolysis is through enzymatic saccharification using cellulases. Significant information has also been gained about the physiology of thermophilic cellulases producers and process development for enzyme production and biomass saccharification. The review discusses the current knowledge on cellulase producing thermophilic microorganisms, their physiological adaptations and control of cellulase gene expression. It discusses the industrial applications of thermophilic cellulases, their cost of production and challenges in cellulase research especially in the area of improving process economics of enzyme production.

  10. Biohydrogen production from specified risk materials co-digested with cattle manure

    Energy Technology Data Exchange (ETDEWEB)

    Gilroyed, Brandon H. [Agriculture and Agri-Food Canada, Lethbridge Research Centre, P.O. Box 3000, Lethbridge, Alberta T1J 4B1 (Canada); Department of Civil Engineering, Schulich School of Engineering, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); Li, Chunli; Hao, Xiying; McAllister, Tim A. [Agriculture and Agri-Food Canada, Lethbridge Research Centre, P.O. Box 3000, Lethbridge, Alberta T1J 4B1 (Canada); Chu, Angus [Department of Civil Engineering, Schulich School of Engineering, University of Calgary, Calgary, Alberta T2N 1N4 (Canada)

    2010-02-15

    Biohydrogen production from the anaerobic digestion of specified risk materials (SRM) co-digested with cattle manure was assessed in a 3 x 5 factorial design. Total organic loading rates (OLR) of 10, 20, and 40 g L{sup -1} volatile solids (VS) were tested using manure:SRM (wt/wt) mixtures of 100:0 (control), 90:10, 80:20, 60:40, and 50:50 using five 2 L continuously stirred biodigesters operating at 55 C. Gas samples were taken daily to determine hydrogen production, and slurry samples were analyzed daily for volatile fatty acid (VFA) concentration, total ammonia nitrogen (TAN), and VS degradation. Hydrogen production (mL g{sup -1} VS fed) varied quadratically according to OLR (P < 0.01), with maximum production at OLR20, while production decreased linearly (P < 0.0001) as SRM concentration increased. Reduced hydrogen production associated with SRM inclusion at >10% VS may be attributed to a rapid increase in TAN (r = -0.55) or other inhibitors such as long chain fatty acids. Reduced hydrogen production (P < 0.01) at OLR40 versus OLR20 may be related to increased rate of VFA accumulation and final VFA concentration (P < 0.001), as well as inhibition due to hydrogen accumulation (P < 0.001). Biohydrogen production from SRM co-digested with cattle manure may not be feasible on an industrial scale due to reduced hydrogen production with increasing levels of SRM. (author)

  11. Bio-hydrogen production from renewable organic wastes

    Energy Technology Data Exchange (ETDEWEB)

    Shihwu Sung

    2004-04-30

    Methane fermentation has been in practice over a century for the stabilization of high strength organic waste/wastewater. Although methanogenesis is a well established process and methane--the end-product of methanogenesis is a useful energy source; it is a low value end product with relatively less energy content (about 56 kJ energy/g CH{sub 4}). Besides, methane and its combustion by-product are powerful greenhouse gases, and responsible for global climate change. So there is a pressing need to explore alternative environmental technologies that not only stabilize the waste/wastewater but also generate benign high value end products. From this perspective, anaerobic bioconversion of organic wastes to hydrogen gas is an attractive option that achieves both goals. From energy security stand point, generation of hydrogen energy from renewable organic waste/wastewater could substitute non-renewable fossil fuels, over two-third of which is imported from politically unstable countries. Thus, biological hydrogen production from renewable organic waste through dark fermentation represents a critically important area of bioenergy production. This study evaluated both process engineering and microbial physiology of biohydrogen production.

  12. Comparative economic assessment of ethanol production under mesophilic and thermophilic conditions

    International Nuclear Information System (INIS)

    Mistry, P.B.

    1991-01-01

    Key technical factors affecting the economics of bioethanol production are critically analyzed with special reference to the relative merits of thermophilic and mesophilic fermentation. A number of novel process schemes to take advantage of thermophilic operation are discussed. Analysis of the capital and operating costs for a range of flowsheets then provides a basis for critical study. Estimates for thermophilic production are compared with those for a sugar cane based mesophilic process (using S. cerevisiae). For the thermophilic fermentation, the basic kinetic and yield constants are based on projected values for a strain of B. stearothermophilus. Compared to mesophilic operation, thermophilic operation results in reduced capital, operating and feed costs. The feed cost still accounts for a large proportion (75%) of the total production cost. However, on a feed-cost-free basis, a reduction in production cost of up to 32% could be realized by changing to thermophilic operation from existing yeast-based processes, after minor process modifications. 20 refs., 10 figs., 8 tabs

  13. Bio-hydrogen production by dark fermentation from organic wastes and residues

    DEFF Research Database (Denmark)

    Liu, Dawei

    Der er stigende opmærksomhed omkring biohydrogen. Ved hydrogen fermentering kan kun en lille del af det organiske materiale eller COD i affald omdannes til hydrogen. Der findes endnu ingen full-skala bio-hydrogen anlæg, eftersom effektive rentable teknologier ikke er udviklet endnu. En to......-trins proces der kombinerer bio-hydrogen og bio-metan produktionen er en attraktiv mulighed til at øge det totale energi-udbytte af fermentering af organisk materiale. I en to-trins proces, med bio-hydrogen som første trin og bio-methan som andet trin, kunne der opnås 43mL-H2/gVSadded ved 37°C fra...... for en hurtig proces opstart og med højt brint effektivitet. Uden berigelseskulturer fejlede processen, på trods af gentagen genpodning. Optimale procesforhold for brint producerende processer blev bestemt. pH optimum af brintproducerende kulturer var 7.0 og acetat var hæmmende for brintproduktionen...

  14. Simultaneous Decolorization and Biohydrogen Production from Xylose by Klebsiella oxytoca GS-4-08 in the Presence of Azo Dyes with Sulfonate and Carboxyl Groups

    Science.gov (United States)

    Cao, Ming-yue; Wang, Peng-tao; Wang, Shi; Yue, Ying-rong; Yuan, Wen-duo; Qiao, Wei-chuan; Wang, Fei

    2017-01-01

    ABSTRACT Biohydrogen production from the pulp and paper effluent containing rich lignocellulosic material could be achieved by the fermentation process. Xylose, an important hemicellulose hydrolysis product, is used less efficiently as a substrate for biohydrogen production. Moreover, azo dyes are usually added to fabricate anticounterfeiting paper, which further increases the complexity of wastewater. This study reports that xylose could serve as the sole carbon source for a pure culture of Klebsiella oxytoca GS-4-08 to achieve simultaneous decolorization and biohydrogen production. With 2 g liter−1 of xylose as the substrate, a maximum xylose utilization rate (URxyl) and a hydrogen molar yield (HMY) of 93.99% and 0.259 mol of H2 mol of xylose−1, respectively, were obtained. Biohydrogen kinetics and electron equivalent (e− equiv) balance calculations indicated that methyl red (MR) penetrates and intracellularly inhibits both the pentose phosphate pathway and pyruvate fermentation pathway, while methyl orange (MO) acted independently of the glycolysis and biohydrogen pathway. The data demonstrate that biohydrogen pathways in the presence of azo dyes with sulfonate and carboxyl groups were different, but the azo dyes could be completely reduced during the biohydrogen production period in the presence of MO or MR. The feasibility of hydrogen production from industrial pulp and paper effluent by the strain if the xylose is sufficient was also proved and was not affected by toxic substances which usually exist in such wastewater, except for chlorophenol. This study offers a promising energy-recycling strategy for treating pulp and paper wastewaters, especially for those containing azo dyes. IMPORTANCE The pulp and paper industry is a major industry in many developing countries, and the global market of pulp and paper wastewater treatment is expected to increase by 60% between 2012 and 2020. Such wastewater contains large amounts of refractory contaminants, such

  15. Potential use and the energy conversion efficiency analysis of fermentation effluents from photo and dark fermentative bio-hydrogen production.

    Science.gov (United States)

    Zhang, Zhiping; Li, Yameng; Zhang, Huan; He, Chao; Zhang, Quanguo

    2017-12-01

    Effluent of bio-hydrogen production system also can be adopted to produce methane for further fermentation, cogeneration of hydrogen and methane will significantly improve the energy conversion efficiency. Platanus Orientalis leaves were taken as the raw material for photo- and dark-fermentation bio-hydrogen production. The resulting concentrations of acetic, butyric, and propionic acids and ethanol in the photo- and dark-fermentation effluents were 2966mg/L and 624mg/L, 422mg/L and 1624mg/L, 1365mg/L and 558mg/L, and 866mg/L and 1352mg/L, respectively. Subsequently, we calculated the energy conversion efficiency according to the organic contents of the effluents and their energy output when used as raw material for methane production. The overall energy conversion efficiencies increased by 15.17% and 22.28%, respectively, when using the effluents of photo and dark fermentation. This two-step bio-hydrogen and methane production system can significantly improve the energy conversion efficiency of anaerobic biological treatment plants. Copyright © 2017. Published by Elsevier Ltd.

  16. Biohydrogen production from waste bread in a continuous stirred tank reactor: A techno-economic analysis.

    Science.gov (United States)

    Han, Wei; Hu, Yun Yi; Li, Shi Yi; Li, Fei Fei; Tang, Jun Hong

    2016-12-01

    Biohydrogen production from waste bread in a continuous stirred tank reactor (CSTR) was techno-economically assessed. The treating capacity of the H 2 -producing plant was assumed to be 2 ton waste bread per day with lifetime of 10years. Aspen Plus was used to simulate the mass and energy balance of the plant. The total capital investment (TCI), total annual production cost (TAPC) and annual revenue of the plant were USD931020, USD299746/year and USD639920/year, respectively. The unit hydrogen production cost was USD1.34/m 3 H 2 (or USD14.89/kg H 2 ). The payback period and net present value (NPV) of the plant were 4.8years and USD1266654, respectively. Hydrogen price and operators cost were the most important variables on the NPV. It was concluded that biohydrogen production from waste bread in the CSTR was feasible for practical application. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Reusing pulp and paper mill effluent as a bioresource to produce biohydrogen through ultrasonicated Rhodobacter sphaeroides

    International Nuclear Information System (INIS)

    Hay, Jacqueline Xiao Wen; Wu, Ta Yeong; Ng, Boon Junn; Juan, Joon Ching; Md Jahim, Jamaliah

    2016-01-01

    Highlights: • Ultrasonication pretreatment on R. sphaeroides enhanced biohydrogen production. • Pretreatment using amplitude 30% for 10 min gave the highest biohydrogen yield. • Pretreatment using amplitude 45% for 15 min inhibited biohydrogen production. - Abstract: Pulp and paper industry is a water-intensive industry. This industry commonly produces considerable amount of effluent, especially from virgin raw materials processing. The effluent, namely pulp and paper mill effluent has the potential to adversely affect the receiving watercourses. However, the nutrients in the pulp and paper mill effluent could be reused as a substrate in biohydrogen production. In this study, photofermentative biohydrogen production was investigated using Rhodobacter sphaeroides and pulp and paper mill effluent as a substrate. An application of low power ultrasound on R. sphaeroides was predicted to increase photofermentative biohydrogen production but excessive ultrasound effects might inhibit the production due to possible cell disruption. Hence, various ultrasonication duration (5, 10 and 15 min) and amplitude (15%, 30% and 45%) were applied on the bacteria to determine the recommended ultrasonication conditions for improving biohydrogen production. The recommended conditions were operated at ultrasonication amplitude and duration of 30% and 10 min, respectively. A maximum biohydrogen yield of 9.62 mL bioH_2/mL medium was obtained under this condition, which was 66.7% higher than the result obtained using R. sphaeroides without undergoing ultrasonication (control). The light efficiency and cell concentration were increased by 67% and 150%, respectively, using ultrasonication amplitude and duration of 30% and 10 min, respectively as compared to the control. The present results demonstrated that moderate power of ultrasonication applied on R. sphaeroides was an effective method for enhancing photofermentative biohydrogen production using raw pulp and paper mill effluent as a

  18. Biohydrogen production from untreated and hydrolyzed potato steam peels by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana

    Energy Technology Data Exchange (ETDEWEB)

    Mars, Astrid E.; Veuskens, Teun; Budde, Miriam A.W.; van Doeveren, Patrick F.N.M.; Lips, Steef J.; Bakker, Robert R.; de Vrije, Truus; Claassen, Pieternel A.M. [Wageningen UR, Food and Biobased Research, P.O. Box 17, 6700 AA Wageningen (Netherlands)

    2010-08-15

    Production of hydrogen by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana was studied in serum flasks and in pH-controlled bioreactors with glucose, and hydrolyzed and untreated potato steam peels (PSP) as carbon sources. Two types of PSP hydrolysates were used: one in which the starch in the PSP was liquefied with alpha-amylase, and one in which the liquefied starch was further hydrolyzed to glucose by amyloglucosidase. When the PSP hydrolysates or untreated PSP were added at circa 10-14 g/L of glucose units, both strains grew well and produced hydrogen with reasonable to high molar yields (2.4-3.8 moles H{sub 2}/mole glucose units), and no significant production of lactate. The hydrogen production rates and yields were similar with untreated PSP, hydrolyzed PSP, and pure glucose, showing that C. saccharolyticus and T. neapolitana are well equipped for the utilization of starch. When the concentrations of the substrates were increased, growth and hydrogen production of both strains were hampered. At substrate concentrations of circa 30-40 g/L of glucose units, the molar hydrogen yield of C. saccharolyticus was severely reduced due to the formation of high amounts of lactate, while T. neapolitana was unable to grow at all. The results showed that PSP and PSP hydrolysates are very suitable substrates for efficient fermentative hydrogen production at moderate substrate loadings. (author)

  19. Production of thermophilic and acidophilic endoglucanases by ...

    African Journals Online (AJOL)

    Production of thermophilic and acidophilic endoglucanases by mutant Trichoderma atroviride 102C1 using agro-industrial by-products. ... The effect of the carbon (sugarcane bagasse: SCB) and nitrogen (corn steep liquor: CSL) sources on ...

  20. Econometric models for biohydrogen development.

    Science.gov (United States)

    Lee, Duu-Hwa; Lee, Duu-Jong; Veziroglu, Ayfer

    2011-09-01

    Biohydrogen is considered as an attractive clean energy source due to its high energy content and environmental-friendly conversion. Analyzing various economic scenarios can help decision makers to optimize development strategies for the biohydrogen sector. This study surveys econometric models of biohydrogen development, including input-out models, life-cycle assessment approach, computable general equilibrium models, linear programming models and impact pathway approach. Fundamentals of each model were briefly reviewed to highlight their advantages and disadvantages. The input-output model and the simplified economic input-output life-cycle assessment model proved most suitable for economic analysis of biohydrogen energy development. A sample analysis using input-output model for forecasting biohydrogen development in the United States is given. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Bioethanol, biohydrogen and biogas production from wheat straw in a biorefinery concept

    DEFF Research Database (Denmark)

    Kaparaju, Prasad Laxmi-Narasimha; Serrano, Maria; Thomsen, Anne Belinda

    2009-01-01

    fermentation of cellulose yielded 0.41 g-ethanol/g-glucose, while dark fermentation of hydrolysate produced 178.0 ml-H-2/g-sugars. The effluents from both bioethanol and biohydrogen processes were further used to produce methane with the yields of 0.324 and 0.381 m(3)/kg volatile solids (VS)added, respectively....... Additionally, evaluation of six different wheat straw-to-biofuel production scenaria showed that either use of wheat straw for biogas production or multi-fuel production were the energetically most efficient processes compared to production of mono-fuel such as bioethanol when fermenting C6 sugars alone. Thus...

  2. Hydrogen production from sugar beet juice using an integrated biohydrogen process of dark fermentation and microbial electrolysis cell.

    Science.gov (United States)

    Dhar, Bipro Ranjan; Elbeshbishy, Elsayed; Hafez, Hisham; Lee, Hyung-Sool

    2015-12-01

    An integrated dark fermentation and microbial electrochemical cell (MEC) process was evaluated for hydrogen production from sugar beet juice. Different substrate to inoculum (S/X) ratios were tested for dark fermentation, and the maximum hydrogen yield was 13% of initial COD at the S/X ratio of 2 and 4 for dark fermentation. Hydrogen yield was 12% of initial COD in the MEC using fermentation liquid end products as substrate, and butyrate only accumulated in the MEC. The overall hydrogen production from the integrated biohydrogen process was 25% of initial COD (equivalent to 6 mol H2/mol hexoseadded), and the energy recovery from sugar beet juice was 57% using the combined biohydrogen. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Biomass production and energy source of thermophiles in a Japanese alkaline geothermal pool.

    Science.gov (United States)

    Kimura, Hiroyuki; Mori, Kousuke; Nashimoto, Hiroaki; Hattori, Shohei; Yamada, Keita; Koba, Keisuke; Yoshida, Naohiro; Kato, Kenji

    2010-02-01

    Microbial biomass production has been measured to investigate the contribution of planktonic bacteria to fluxations in dissolved organic matter in marine and freshwater environments, but little is known about biomass production of thermophiles inhabiting geothermal and hydrothermal regions. The biomass production of thermophiles inhabiting an 85 degrees C geothermal pool was measured by in situ cultivation using diffusion chambers. The thermophiles' growth rates ranged from 0.43 to 0.82 day(-1), similar to those of planktonic bacteria in marine and freshwater habitats. Biomass production was estimated based on cellular carbon content measured directly from the thermophiles inhabiting the geothermal pool, which ranged from 5.0 to 6.1 microg C l(-1) h(-1). This production was 2-75 times higher than that of planktonic bacteria in other habitats, because the cellular carbon content of the thermophiles was much higher. Quantitative PCR and phylogenetic analysis targeting 16S rRNA genes revealed that thermophilic H2-oxidizing bacteria closely related to Calderobacterium and Geothermobacterium were dominant in the geothermal pool. Chemical analysis showed the presence of H2 in gases bubbling from the bottom of the geothermal pool. These results strongly suggested that H2 plays an important role as a primary energy source of thermophiles in the geothermal pool.

  4. Thermophilic fermentative hydrogen production from starch-wastewater with bio-granules

    Energy Technology Data Exchange (ETDEWEB)

    Akutsu, Yohei; Harada, Hideki [Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Sendai, Miyagi 980-8579 (Japan); Lee, Dong-Yeol [Research Center for Material Cycles and Waste Management, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan); Chi, Yong-Zhi [Department of Environmental and Municipal Engineering, Tianjin Institute of Urban Construction, Jinjinggonglu 26, Tianjin 300384 (China); Li, Yu-You [Department of Environmental and Municipal Engineering, Tianjin Institute of Urban Construction, Jinjinggonglu 26, Tianjin 300384 (China); Department of Environmental Science, Tohoku University, 6-6-06 Aoba, Sendai, Miyagi 980-8579 (Japan); Yu, Han-Qing [School of Chemistry, University of Science and Technology of China, Hefei 230026 (China)

    2009-06-15

    In this study, the effects of the hydraulic retention time (HRT), pH and substrate concentration on the thermophilic hydrogen production of starch with an upflow anaerobic sludge bed (UASB) reactor were investigated. Starch was used as a sole substrate. Continuous hydrogen production was stably attained with a maximum H{sub 2} yield of 1.7 mol H{sub 2}/mol glucose. A H{sub 2}-producing thermophilic granule was successfully formed with diameter in the range of 0.5-4.0 mm with thermally pretreated methanogenic granules as the nuclei. The metabolic pathway of the granules was drastically changed at each operational parameter. The production of formic or lactic acids is an indication of the deterioration of hydrogen production for H{sub 2}-producing thermophilic granular sludge. (author)

  5. Timeline of bio-hydrogen production by anaerobic digestion of biomass

    Directory of Open Access Journals (Sweden)

    Bernadette E. TELEKY

    2015-12-01

    Full Text Available Anaerobic digestion of biomass is a process capable to produce biohydrogen, a clean source of alternative energy. Lignocellulosic biomass from agricultural waste is considered a renewable energy source; therefore its utilization also contributes to the reduction of water, soil and air pollution. The study consists in five consecutive experiments designed to utilize anaerobic bacterial enrichment cultures originating from the Hungarian Lake, Hévíz. Wheat straw was used as complex substrate to produce hydrogen. The timeline evolution of hydrogen production was analyzed and modelled by two functions: Logistic and Boltzmann. The results proved that hydrogen production is significant, with a maximum of 0.24 mlN/ml and the highest hydrogen production occurs between the days 4-10 of the experiment.

  6. Fermentative biohydrogen and biomethane co-production from mixture of food waste and sewage sludge: Effects of physiochemical properties and mix ratios on fermentation performance

    International Nuclear Information System (INIS)

    Cheng, Jun; Ding, Lingkan; Lin, Richen; Yue, Liangchen; Liu, Jianzhong; Zhou, Junhu; Cen, Kefa

    2016-01-01

    Highlights: • Microanalyses revealed food waste had more gelatinized organics and less mineral ash. • Mixed food waste and sewage sludge at 5 ratios were used for H_2 and CH_4 co-production. • Highest H_2 yield of 174.6 mL/gVS was achieved when food waste:sewage sludge was 3:1. • Co-fermentation enhanced carbon conversion by strengthening hydrolysis of substrates. • Energy yield rose from 1.9 kJ/gVS in H_2 to 11.3 kJ/gVS in H_2 and CH_4 co-production. - Abstract: The accumulation of increasingly generated food waste and sewage sludge is currently a heavy burden on environment in China. In this study, the physiochemical properties of food waste and sewage sludge were identified using scanning electron microscopy and Fourier transform infrared spectroscopy to investigate the effects on the fermentation performance in the co-fermentation of food waste and sewage sludge for biohydrogen production. The high gelatinized organic components in food waste, the enhanced bioaccessibility due to the dilution of mineral compounds in sewage sludge, and the balanced C/N ratio synergistically improved the fermentative biohydrogen production through the co-fermentation of food waste and sewage sludge at a volatile solids (VS) mix ratio of 3:1. The biohydrogen yield of 174.6 mL/gVS was 49.9% higher than the weighted average calculated from mono-fermentation of food waste and sewage sludge. Co-fermentation also strengthened the hydrolysis and acidogenesis of the mixture, resulting in a total carbon conversion efficiency of 63.3% and an energy conversion efficiency of 56.6% during biohydrogen production. After the second-stage anaerobic digestion of hydrogenogenic effluent, the energy yield from the mixed food waste and sewage sludge significantly increased from 1.9 kJ/gVS in the first-stage biohydrogen production to 11.3 kJ/gVS in the two-stage fermentative biohydrogen and biomethane co-production.

  7. Survey on the possibility of international cooperation on production technology of biohydrogen; Bio suiso seizo gijutsu ni kakawaru kokusai kyoryoku kanosei chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    R and D on the production technology of hydrogen by biotechnology is one of the effective projects for worldwide energy supply technology and global environment protection technology in the 21st century. The research trend of various institutions promoting R and D on production technology of biohydrogen in the U.S.A. and other countries was surveyed together with the possibility of international cooperation. The production technology of biohydrogen is being watched over the world. Various researches are in promotion corresponding to environmental conditions as follows: search of not only photosynthetic bacteria but also such bacteria with hydrogen productivity as algae and anaerobic bacteria, and the gene engineering study for improving the hydrogen productivity of target microorganisms. All the institutions visited for this survey have great expectations in wide cooperative study in the future. On the possibility of international cooperation on the production technology of biohydrogen, the further precise survey should be promoted for developing more effective technologies based on the previous survey results. 156 refs., 10 tabs.

  8. Continuous fermentative hydrogen production from cheese whey wastewater under thermophilic anaerobic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Azbar, Nuri; Cetinkaya Dokgoez, F. Tuba; Keskin, Tugba; Korkmaz, Kemal S.; Syed, Hamid M. [Bioengineering Department, Faculty of Engineering, Ege University, EBILTEM, Bornova, 35100 Izmir (Turkey)

    2009-09-15

    Hydrogen (H{sub 2}) production from cheese processing wastewater via dark anaerobic fermentation was conducted using mixed microbial communities under thermophilic conditions. The effects of varying hydraulic retention time (HRT: 1, 2 and 3.5 days) and especially high organic load rates (OLR: 21, 35 and 47 g chemical oxygen demand (COD)/l/day) on biohydrogen production in a continuous stirred tank reactor were investigated. The biogas contained 5-82% (45% on average) hydrogen and the hydrogen production rate ranged from 0.3 to 7.9 l H{sub 2}/l/day (2.5 l/l/day on average). H{sub 2} yields of 22, 15 and 5 mmol/g COD (at a constant influent COD of 40 g/l) were achieved at HRT values of 3.5, 2, and 1 days, respectively. On the other hand, H{sub 2} yields were monitored to be 3, 9 and 6 mmol/g COD, for OLR values of 47, 35 and 21 g COD/l/day, when HRT was kept constant at 1 day. The total measurable volatile fatty acid concentration in the effluent (as a function of influent COD) ranged between 118 and 27,012 mg/l, which was mainly composed of acetic acid, iso-butyric acid, butyric acid, propionic acid, formate and lactate. Ethanol and acetone production was also monitored from time to time. To characterize the microbial community in the bioreactor at different HRTs, DNA in mixed liquor samples was extracted immediately for PCR amplification of 16S RNA gene using eubacterial primers corresponding to 8F and 518R. The PCR product was cloned and subjected to DNA sequencing. The sequencing results were analyzed by using MegaBlast available on NCBI website which showed 99% identity to uncultured Thermoanaerobacteriaceae bacterium. (author)

  9. Scale-up and optimization of biohydrogen production reactor from laboratory-scale to industrial-scale on the basis of computational fluid dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xu; Ding, Jie; Guo, Wan-Qian; Ren, Nan-Qi [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 202 Haihe Road, Nangang District, Harbin, Heilongjiang 150090 (China)

    2010-10-15

    The objective of conducting experiments in a laboratory is to gain data that helps in designing and operating large-scale biological processes. However, the scale-up and design of industrial-scale biohydrogen production reactors is still uncertain. In this paper, an established and proven Eulerian-Eulerian computational fluid dynamics (CFD) model was employed to perform hydrodynamics assessments of an industrial-scale continuous stirred-tank reactor (CSTR) for biohydrogen production. The merits of the laboratory-scale CSTR and industrial-scale CSTR were compared and analyzed on the basis of CFD simulation. The outcomes demonstrated that there are many parameters that need to be optimized in the industrial-scale reactor, such as the velocity field and stagnation zone. According to the results of hydrodynamics evaluation, the structure of industrial-scale CSTR was optimized and the results are positive in terms of advancing the industrialization of biohydrogen production. (author)

  10. One-carbon substrate-based biohydrogen production: microbes, mechanism, and productivity.

    Science.gov (United States)

    Rittmann, Simon K-M R; Lee, Hyun Sook; Lim, Jae Kyu; Kim, Tae Wan; Lee, Jung-Hyun; Kang, Sung Gyun

    2015-01-01

    Among four basic mechanisms for biological hydrogen (H2) production, dark fermentation has been considered to show the highest hydrogen evolution rate (HER). H2 production from one-carbon (C1) compounds such as formate and carbon monoxide (CO) is promising because formate is an efficient H2 carrier, and the utilization of CO-containing syngas or industrial waste gas may render the industrial biohydrogen production process cost-effective. A variety of microbes with the formate hydrogen lyase (FHL) system have been identified from phylogenetically diverse groups of archaea and bacteria, and numerous efforts have been undertaken to improve the HER for formate through strain optimization and bioprocess development. CO-dependent H2 production has been investigated to enhance the H2 productivity of various carboxydotrophs via an increase in CO gas-liquid mass transfer rates and the construction of genetically modified strains. Hydrogenogenic CO-conversion has been applied to syngas and by-product gas of the steel-mill process, and this low-cost feedstock has shown to be promising in the production of biomass and H2. Here, we focus on recent advances in the isolation of novel phylogenetic groups utilizing formate or CO, the remarkable genetic engineering that enhances H2 productivity, and the practical implementation of H2 production from C1 substrates. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Ruminal Biohydrogenation Pattern of Poly-Unsaturated Fatty Acid as Influenced by Dietary Tannin

    Directory of Open Access Journals (Sweden)

    Anuraga Jayanegara

    2013-09-01

    Full Text Available Large amounts of polyunsaturated fatty acids undergo transformation processes in the rumen through microbial biohydrogenation to form fatty acids with higher saturation degree. The respective process explains the high content of saturated fatty acids in products of ruminants and the potential risk of consumers’ health by consuming such products. Various nutritional approaches have been attempted to modulate biohydrogenation process in order to obtain healthier fatty acid profile from consumers’ perspective. The present paper is aimed to review the influence of dietary tannin, a naturally produced plant secondary compound, on the pattern of polyunsaturated fatty acids biohydrogenation occurring in the rumen. The effect of tannin on some key fatty acids involved in biohydrogenation process is presented together with the underlying mechanisms, particularly from up-to-date research results. Accordingly, different form of tannin as well as different level of the application are also discussed.

  12. Effect of Inlet Velocity on Heat Transfer Process in a Novel Photo-Fermentation Biohydrogen Production Bioreactor using Computational Fluid Dynamics Simulation

    Directory of Open Access Journals (Sweden)

    Zhiping Zhang

    2014-11-01

    Full Text Available Temperature is one of the most important parameters in biohydrogen production by way of photo-fermentation. Enzymatic hydrolysate of corncob powder was utilized as a substrate. Computational fluid dynamics (CFD modeling was conducted to simulate the temperature distribution in an up-flow baffle photo-bioreactor (UBPB. Commercial software, GAMBIT, was utilized to mesh the photobioreactor geometry, while the software FLUENT was adopted to simulate the heat transfer in the photo-fermentation process. The inlet velocity had a marked impact on heat transfer; the most optimum velocity value was 0.0036 m•s-1 because it had the smallest temperature fluctuation and the most uniform temperature distribution. When the velocity decreased from 0.0036 m•s-1 to 0.0009 m•s-1, more heat was accumulated. The results obtained from the established model were consistent to the actual situation by comparing the simulation values and experimental values. The hydrogen production simulation verified that the novel UBPB was suitable for biohydrogen production by photosynthetic bacteria because of its uniform temperature and lighting distribution, with the serpentine flow pattern also providing mixing without additional energy input, thus enhancing the mass transfer and biohydrogen yield.

  13. A farm-scale pilot plant for biohydrogen and biomethane production by two-stage fermentation

    Directory of Open Access Journals (Sweden)

    R. Oberti

    2013-09-01

    Full Text Available Hydrogen is considered one of the possible main energy carriers for the future, thanks to its unique environmental properties. Indeed, its energy content (120 MJ/kg can be exploited virtually without emitting any exhaust in the atmosphere except for water. Renewable production of hydrogen can be obtained through common biological processes on which relies anaerobic digestion, a well-established technology in use at farm-scale for treating different biomass and residues. Despite two-stage hydrogen and methane producing fermentation is a simple variant of the traditional anaerobic digestion, it is a relatively new approach mainly studied at laboratory scale. It is based on biomass fermentation in two separate, seuqential stages, each maintaining conditions optimized to promote specific bacterial consortia: in the first acidophilic reactorhydrogen is produced production, while volatile fatty acids-rich effluent is sent to the second reactor where traditional methane rich biogas production is accomplished. A two-stage pilot-scale plant was designed, manufactured and installed at the experimental farm of the University of Milano and operated using a biomass mixture of livestock effluents mixed with sugar/starch-rich residues (rotten fruits and potatoes and expired fruit juices, afeedstock mixture based on waste biomasses directly available in the rural area where plant is installed. The hydrogenic and the methanogenic reactors, both CSTR type, had a total volume of 0.7m3 and 3.8 m3 respectively, and were operated in thermophilic conditions (55 2 °C without any external pH control, and were fully automated. After a brief description of the requirements of the system, this contribution gives a detailed description of its components and of engineering solutions to the problems encountered during the plant realization and start-up. The paper also discusses the results obtained in a first experimental run which lead to production in the range of previous

  14. Innovative self-powered submersible microbial electrolysis cell (SMEC) for biohydrogen production from anaerobic reactors

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Angelidaki, Irini

    2012-01-01

    A self-powered submersible microbial electrolysis cell (SMEC), in which a specially designed anode chamber and external electricity supply were not needed, was developed for in situ biohydrogen production from anaerobic reactors. In batch experiments, the hydrogen production rate reached 17.8 m...... improvement of voltage output and reduction of electron losses were essential for efficient hydrogen generation. In addition, alternate exchanging the electricity-assisting and hydrogen-producing function between the two cell units of the SMEC was found to be an effective approach to inhibit methanogens...

  15. Bayesian Computational Approaches for Gene Regulation Studies of Bioethanol and Biohydrogen Production. Final Scientific/Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Newberg, Lee; McCue, Lee Anne; Van Roey, Patrick

    2014-04-17

    The project developed mathematical models and first-version software tools for the understanding of gene regulation across multiple related species. The project lays the foundation for understanding how certain alpha-proteobacterial species control their own genes for bioethanol and biohydrogen production, and sets the stage for exploiting bacteria for the production of fuels. Enabling such alternative sources of fuel is a high priority for the Department of Energy and the public.

  16. Particle size variations of activated carbon on biofilm formation in thermophilic biohydrogen production from palm oil mill effluent

    International Nuclear Information System (INIS)

    Jamali, Nur Syakina; Jahim, Jamaliah Md; Isahak, Wan Nor Roslam Wan; Abdul, Peer Mohamed

    2017-01-01

    Highlights: • Biofilm was developed on GAC by self-attachment immobilisation. • Effect of various micropore size of GAC was evaluated in H_2 production. • Capability of attached-biofilm to degrade cellulosic fibre in POME was evaluated. • Microbial community colonized on GAC was characterised. - Abstract: In this study, we examined the formation of thermophilic microbial biofilm by self-attachment on microbial carrier of granular activated carbon (GAC) in five different micro-pore volumes 0.31, 0.41, 0.44, 0.48, and 0.50 cm"3/g. It was found that the highest hydrogen production rate of 100.8 ± 3.7 mmol H_2/l.d and yield of 1.01 ± 0.07 mol H_2/mol sugar were obtained at 0.44 cm"3/g volume size of GAC. The cellulolytic activity of attached-biofilm was further investigated using POME as a feedstock. The results showed that in all diluted POME substrate, the total sugar consumed by the microbes was found higher than that the amount of soluble monomeric sugar present in the POME medium. It is believe that the microbial biofilm was able to hydrolyse polymeric sugar of cellulosic fibre in the POME by performing enzymatic hydrolysis into simple monomeric sugar. The isolated biofilm bacteria that subjected to 16S rRNA gene analysis presented 99% high homology to the species of Thermoanaerobacterium thermosaccharolyticum which were guaranteed to perform a cellulosic degradation activity.

  17. Single-step ethanol production from lignocellulose using novel extremely thermophilic bacteria.

    Science.gov (United States)

    Svetlitchnyi, Vitali A; Kensch, Oliver; Falkenhan, Doris A; Korseska, Svenja G; Lippert, Nadine; Prinz, Melanie; Sassi, Jamaleddine; Schickor, Anke; Curvers, Simon

    2013-02-28

    Consolidated bioprocessing (CBP) of lignocellulosic biomass to ethanol using thermophilic bacteria provides a promising solution for efficient lignocellulose conversion without the need for additional cellulolytic enzymes. Most studies on the thermophilic CBP concentrate on co-cultivation of the thermophilic cellulolytic bacterium Clostridium thermocellum with non-cellulolytic thermophilic anaerobes at temperatures of 55°C-60°C. We have specifically screened for cellulolytic bacteria growing at temperatures >70°C to enable direct conversion of lignocellulosic materials into ethanol. Seven new strains of extremely thermophilic anaerobic cellulolytic bacteria of the genus Caldicellulosiruptor and eight new strains of extremely thermophilic xylanolytic/saccharolytic bacteria of the genus Thermoanaerobacter isolated from environmental samples exhibited fast growth at 72°C, extensive lignocellulose degradation and high yield ethanol production on cellulose and pretreated lignocellulosic biomass. Monocultures of Caldicellulosiruptor strains degraded up to 89-97% of the cellulose and hemicellulose polymers in pretreated biomass and produced up to 72 mM ethanol on cellulose without addition of exogenous enzymes. In dual co-cultures of Caldicellulosiruptor strains with Thermoanaerobacter strains the ethanol concentrations rose 2- to 8.2-fold compared to cellulolytic monocultures. A co-culture of Caldicellulosiruptor DIB 087C and Thermoanaerobacter DIB 097X was particularly effective in the conversion of cellulose to ethanol, ethanol comprising 34.8 mol% of the total organic products. In contrast, a co-culture of Caldicellulosiruptor saccharolyticus DSM 8903 and Thermoanaerobacter mathranii subsp. mathranii DSM 11426 produced only low amounts of ethanol. The newly discovered Caldicellulosiruptor sp. strain DIB 004C was capable of producing unexpectedly large amounts of ethanol from lignocellulose in fermentors. The established co-cultures of new Caldicellulosiruptor

  18. Substrate and product inhibition of hydrogen production by the extreme thermophile, Caldicellulosiruptor saccharolyticus

    NARCIS (Netherlands)

    Niel, van E.W.J.; Claassen, P.A.M.; Stams, A.J.M.

    2003-01-01

    Substrate and product inhibition of hydrogen production during sucrose fermentation by the extremely thermophilic bacterium Caldicellulosiruptor saccharolyticus was studied. The inhibition kinetics were analyzed with a noncompetitive, nonlinear inhibition model. Hydrogen was the most severe

  19. Biohydrogen Production and Kinetic Modeling Using Sediment Microorganisms of Pichavaram Mangroves, India

    Directory of Open Access Journals (Sweden)

    P. Mullai

    2013-01-01

    Full Text Available Mangrove sediments host rich assemblages of microorganisms, predominantly mixed bacterial cultures, which can be efficiently used for biohydrogen production through anaerobic dark fermentation. The influence of process parameters such as effect of initial glucose concentration, initial medium pH, and trace metal (Fe2+ concentration was investigated in this study. A maximum hydrogen yield of 2.34, 2.3, and 2.6 mol H2 mol−1 glucose, respectively, was obtained under the following set of optimal conditions: initial substrate concentration—10,000 mg L−1, initial pH—6.0, and ferrous sulphate concentration—100 mg L−1, respectively. The addition of trace metal to the medium (100 mg L−1 FeSO4·7H2O enhanced the biohydrogen yield from 2.3 mol H2 mol−1 glucose to 2.6 mol H2 mol−1 glucose. Furthermore, the experimental data was subjected to kinetic analysis and the kinetic constants were estimated with the help of well-known kinetic models available in the literature, namely, Monod model, logistic model and Luedeking-Piret model. The model fitting was found to be in good agreement with the experimental observations, for all the models, with regression coefficient values >0.92.

  20. Utilization of keratin-containing biowaste to produce biohydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Balint, B.; Rakhely, G.; Kovacs, K.L. [Szeged Univ. (Hungary). Dept. of Biotechnology; Hungarian Academy of Sciences, Szeged (Hungary). Inst. of Biophysics; Bagi, Z.; Perei, K. [Szeged Univ. (Hungary). Dept. of Biotechnology; Toth, A. [Hungarian Academy of Sciences, Szeged (Hungary). Inst. of Biophysics

    2005-12-01

    A two-stage fermentation system was constructed to test and demonstrate the feasibility of biohydrogen generation from keratin-rich biowaste. We isolated a novel aerobic Bacillus strain (Bacillus licheniformis KK1) that displays outstanding keratinolytic activity. The isolated strain was employed to convert keratin-containing biowaste into a fermentation product that is rich in amino acids and peptides. The process was optimized for the second fermentation step, in which the product of keratin fermentation-supplemented with essential minerals-was metabolized by Thermococcus litoralis, an anaerobic hyperthermophilic archaeon. T. litoralis grew on the keratin hydrolysate and produced hydrogen gas as a physiological fermentation byproduct. Hyperthermophilic cells utilized the keratin hydrolysate in a similar way as their standard nutrient, i.e., bacto-peptone. The generalization of the findings to protein-rich waste treatment and production of biohydrogen is discussed and possible means of further improvements are listed. (orig.)

  1. State of the art review of biofuels production from lignocellulose by thermophilic bacteria.

    Science.gov (United States)

    Jiang, Yujia; Xin, Fengxue; Lu, Jiasheng; Dong, Weiliang; Zhang, Wenming; Zhang, Min; Wu, Hao; Ma, Jiangfeng; Jiang, Min

    2017-12-01

    Biofuels, including ethanol and butanol, are mainly produced by mesophilic solventogenic yeasts and Clostridium species. However, these microorganisms cannot directly utilize lignocellulosic materials, which are abundant, renewable and non-compete with human demand. More recently, thermophilic bacteria show great potential for biofuels production, which could efficiently degrade lignocellulose through the cost effective consolidated bioprocessing. Especially, it could avoid contamination in the whole process owing to its relatively high fermentation temperature. However, wild types thermophiles generally produce low levels of biofuels, hindering their large scale production. This review comprehensively summarizes the state of the art development of biofuels production by reported thermophilic microorganisms, and also concludes strategies to improve biofuels production including the metabolic pathways construction, co-culturing systems and biofuels tolerance. In addition, strategies to further improve butanol production are proposed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. The operation characteristics of biohydrogen production in continuous stirred tank reactor with molasses

    Energy Technology Data Exchange (ETDEWEB)

    Hong, C.; Wei, H.; Jie-xuan, D.; Xin, Y.; Chuan-ping, Y. [Northeast Forestry Univ., Harbin (China). School of Forestry; Li, Y.F. [Northeast Forestry Univ., Harbin (China). School of Forestry; Shanghai Univ. Engineering, Shanghai (China). College of Chemistry and Chemical Engineering

    2010-07-01

    The anaerobic fermentation biohydrogen production in a continuous stirred tank reactor (CSTR) was investigated as a means for treating molasses wastewater. The research demonstrated that the reactor has the capacity of continuously producing hydrogen in an initial biomass (as volatile suspension solids) of 17.74 g/L, temperature of approximately 35 degrees Celsius, hydraulic retention time of 6 hours. The reactor could begin the ethanol-type fermentation in 12 days and realize stable hydrogen production. The study also showed that the CSTR reactor has a favourable stability even with an organic shock loading. The hydrogen yield and chemical oxygen demand (COD) increased, as did the hydrogen content.

  3. Acid Pretreatment of Sago Wastewater for Biohydrogen Production

    Science.gov (United States)

    Illi Mohamad Puad, Noor; Rahim, Nurainin Farhan Abd; Suhaida Azmi, Azlin

    2018-03-01

    Biohydrogen has been recognized to be one of the future renewable energy sources and has the potential in solving the greenhouse effects. In this study, Enterobacter aerogenes (E. aerogenes) was used as the biohydrogen producer via dark fermentation process using sago wastewater as the substrate. However, pretreatment of sago wastewater is required since it consists of complex sugars that cannot be utilized directly by the bacteria. This study aimed to use acid pretreatment method to produce high amount of glucose from sago wastewater. Three different types of acid: sulfuric acid (H2SO4); hydrochloric acid (HCl) and nitric acid (HNO3) were screened for the best acid in producing a maximum amount of glucose. H2SO4 gave the highest amount of glucose which was 9.406 g/L. Design of experiment was done using Face-centred Central Composite Design (FCCCD) tool under Response Surface Methodology (RSM) in Design Expert 9 software. The maximum glucose (9.138 g/L) was recorded using 1 M H2SO4 at 100 °C for 60 min. A batch dark fermentation using E. aerogenes was carried out and it was found that pretreated sago wastewater gave a higher hydrogen concentration (1700 ppm) compared to the raw wastewater (410 ppm).

  4. Bio-hydrogen production by Enterobacter asburiae SNU-1 isolated from a landfill

    Energy Technology Data Exchange (ETDEWEB)

    Jong-Hwan Shin; Jong Hyun Yoon; Tai Hyun Park [School of Chemical and Biological Engineering, Seoul National University, Seoul 151-744, (Korea, Republic of)

    2006-07-01

    A new fermentative hydrogen-producing bacterium was isolated from a landfill, and it was identified as Enterobacter asburiae strain using a genomic DNA hybridization method. Environmental factors and metabolic flux influencing the hydrogen production were investigated, including pH, initial glucose and formate concentrations. The major hydrogen production pathway of this strain is considered to be a formate pathway by using formate hydrogen lyase (FHL). Optimum pH for the hydrogen production was pH 7.0 in PYG medium, at which hydrogen production/unit volume and overall hydrogen productivity were 2615 ml/l and 174 ml H{sub 2}/l/hr, respectively, at 25 g glucose/l. The maximum hydrogen productivity was estimated to be 417 ml H{sub 2}/l/hr at 15 g glucose/l. This strain produced bio-hydrogen mostly in the stationary phase, in which formate concentration was high. In this paper, hydrogen production was tried in formate medium after cell harvest. (authors)

  5. Bio-hydrogen production by Enterobacter asburiae SNU-1 isolated from a landfill

    International Nuclear Information System (INIS)

    Jong-Hwan Shin; Jong Hyun Yoon; Tai Hyun Park

    2006-01-01

    A new fermentative hydrogen-producing bacterium was isolated from a landfill, and it was identified as Enterobacter asburiae strain using a genomic DNA hybridization method. Environmental factors and metabolic flux influencing the hydrogen production were investigated, including pH, initial glucose and formate concentrations. The major hydrogen production pathway of this strain is considered to be a formate pathway by using formate hydrogen lyase (FHL). Optimum pH for the hydrogen production was pH 7.0 in PYG medium, at which hydrogen production/unit volume and overall hydrogen productivity were 2615 ml/l and 174 ml H 2 /l/hr, respectively, at 25 g glucose/l. The maximum hydrogen productivity was estimated to be 417 ml H 2 /l/hr at 15 g glucose/l. This strain produced bio-hydrogen mostly in the stationary phase, in which formate concentration was high. In this paper, hydrogen production was tried in formate medium after cell harvest. (authors)

  6. Potential for using thermophilic anaerobic bacteria for bioethanol production from hemicellulose

    DEFF Research Database (Denmark)

    Sommer, P.; Georgieva, Tania I.; Ahring, Birgitte Kiær

    2004-01-01

    A limited number of bacteria, yeast and fungi can convert hemicellulose or its monomers (xylose, arabinose, mannose and galactose) into ethanol with a satisfactory yield and productivity. In the present study we tested a number of thermophilic enrichment cultures, and new isolates of thermophilic...... Of D-Xylose into ethanol; (ii) test for viability and ethanol production in pretreated wheat straw hemicellulose hydrolysate; (iii) test for tolerance against high D-xylose concentrations. A total of 86 enrichment cultures and 58 pure cultures were tested and five candidates were selected which...

  7. Optimization of biohydrogen production from beer lees using anaerobic mixed bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Maojin; Yuan, Zhuliang; Zhi, Xiaohua; Shen, Jianquan [Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun North First Street 2, Beijing 100190 (China)

    2009-10-15

    Beer lees are the main by-product of the brewing industry. Biohydrogen production from beer lees using anaerobic mixed bacteria was investigated in this study, and the effects of acidic pretreatment, initial pH value and ferrous iron concentration on hydrogen production were studied at 35 C in batch experiments. The hydrogen yield was significantly enhanced by optimizing environmental factors such as hydrochloric acid (HCl) pretreatment of substrate, initial pH value and ferrous iron concentration. The optimal environmental factors of substrate pretreated with 2% HCl, pH = 7.0 and 113.67 mg/l Fe{sup 2+} were observed. A maximum cumulative hydrogen yield of 53.03 ml/g-dry beer lees was achieved, which was approximately 17-fold greater than that in raw beer lees. In addition, the degradation efficiency of the total reducing sugar, and the contents of hemicellulose, cellulose, lignin and metabolites are presented, which showed a strong dependence on the environmental factors. (author)

  8. Enterobacter aerogenes metabolites enhance Microcystis aeruginosa biomass recovery for sustainable bioflocculant and biohydrogen production.

    Science.gov (United States)

    Xu, Liang; Zhou, Mo; Ju, Hanyu; Zhang, Zhenxing; Zhang, Jiquan; Sun, Caiyun

    2018-04-07

    We report a recycling bioresource involving harvesting of Microcystis aeruginosa using the bioflocculant (MBF-32) produced by Enterobacter aerogenes followed by the recovery of the harvested M. aeruginosa as the main substrate for the sustainable production of MBF-32 and biohydrogen. The experimental results indicate that the efficiency of bioflocculation exceeded 90% under optimal conditions. The harvested M. aeruginosa was further recycled as the main substrate for the supply of necessary elements. The highest yield (3.6±0.1g/L) of MBF-32 could be obtained from 20g/L of wet biomass of M. aeruginosa with an additional 20g/L of glucose as the extra carbon source. The highest yield of biohydrogen was 35mL of H 2 /g (dw) algal biomass, obtained from 20g/L of wet biomass of M. aeruginosa with an additional 10g/L of glycerol. Transcriptome analyses indicated that MBF-32 was mainly composed of polysaccharide and tyrosine/tryptophan proteins. Furthermore, NADH synthase and polysaccharide export-related genes were found to be up-regulated. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Feasibility of bio-hydrogen production from sewage sludge using defined microbial consortium

    Energy Technology Data Exchange (ETDEWEB)

    Shireen Meher Kotay; Debabrata Das [Fermentation Technology Lab., Department of Biotechnology, Indian Institute of Technology Kharagpur, W.B., INDIA-721302 (India)

    2006-07-01

    Biological hydrogen production potential of a defined microbial consortium consisting of three facultative anaerobes, Enterobacter cloacae IIT-BT 08, Citrobacter freundii IIT-BT L139 and Bacillus coagulans IIT-BT S1 was studied. In this investigation their individual and combinatorial H{sub 2} production capabilities have been studied on defined media and pretreated sewage sludge. Defined medium, MYG (1% w/v Malt extract, 0.4% w/v yeast extract and 1% w/v glucose) with glucose as limiting substrate has been found to be most suitable for hydrogen production. Individually E. cloacae clearly gave higher yield (276 ml H{sub 2}/ g COD reduced) using defined medium than the other two strains. There was no considerable difference in maximal yield of hydrogen from individual and combinatorial (1:1:1 consortium) modes suggesting that E. cloacae dominated in the consortia on defined medium. Contradictorily, B. coagulans gave better bio-hydrogen yield (37.16 ml H{sub 2}/g COD consumed) than the other two strains when activated sewage sludge was used as substrate. The pretreatment of sludge included sterilization, (15% v/v) dilution and supplementation with 0.5%w/v glucose which was found to be essential to screen out the hydrogen consuming bacteria and ameliorate the hydrogenation. Considering (1:1:1) consortium as inoculum, interestingly yield of hydrogen was recorded to increase to 41.23 ml H{sub 2}/ g COD reduced inferring that in consortium, the substrate utilization was significantly higher. The hydrogen yield from pretreated sludge obtained in this study (35.54 ml H{sub 2} g sludge) has been found to be distinctively higher than the earlier reports (8.1 - 16.9 ml H{sub 2}/g sludge). However it was lower compared to the yield obtained from co-digestion of (83:17) food waste and sewage sludge (122 ml H{sub 2}/g carbohydrate COD). Employing formulated microbial consortia for bio-hydrogen production from sewage sludge was an attempt to augment the hydrogen yield from sludge

  10. Feasibility of bio-hydrogen production from sewage sludge using defined microbial consortium

    Energy Technology Data Exchange (ETDEWEB)

    Shireen Meher Kotay; Debabrata Das [Fermentation Technology Lab., Department of Biotechnology, Indian Institute of Technology Kharagpur, W.B., INDIA-721302 (India)

    2006-07-01

    Biological hydrogen production potential of a defined microbial consortium consisting of three facultative anaerobes, Enterobacter cloacae IIT-BT 08, Citrobacter freundii IIT-BT L139 and Bacillus coagulans IIT-BT S1 was studied. In this investigation their individual and combinatorial H{sub 2} production capabilities have been studied on defined media and pretreated sewage sludge. Defined medium, MYG (1% w/v Malt extract, 0.4% w/v yeast extract and 1% w/v glucose) with glucose as limiting substrate has been found to be most suitable for hydrogen production. Individually E. cloacae clearly gave higher yield (276 ml H{sub 2}/ g COD reduced) using defined medium than the other two strains. There was no considerable difference in maximal yield of hydrogen from individual and combinatorial (1:1:1 consortium) modes suggesting that E. cloacae dominated in the consortia on defined medium. Contradictorily, B. coagulans gave better bio-hydrogen yield (37.16 ml H{sub 2}/ g COD consumed) than the other two strains when activated sewage sludge was used as substrate. The pretreatment of sludge included sterilization, (15% v/v) dilution and supplementation with 0.5% w/v glucose which was found to be essential to screen out the hydrogen consuming bacteria and ameliorate the hydrogenation. Considering (1:1:1) consortium as inoculum, interestingly yield of hydrogen was recorded to increase to 41.23 ml H{sub 2}/ g COD reduced inferring that in consortium, the substrate utilization was significantly higher. The hydrogen yield from pretreated sludge obtained in this study (35.54 ml H{sub 2}/ g sludge) has been found to be distinctively higher than the earlier reports (8.1 - 16.9 ml H{sub 2} / g sludge). However it was lower compared to the yield obtained from co-digestion of (83:17) food waste and sewage sludge (122 ml H{sub 2}/ g carbohydrate COD). Employing formulated microbial consortia for bio-hydrogen production from sewage sludge was an attempt to augment the hydrogen yield from

  11. Feasibility of bio-hydrogen production from sewage sludge using defined microbial consortium

    International Nuclear Information System (INIS)

    Shireen Meher Kotay; Debabrata Das

    2006-01-01

    Biological hydrogen production potential of a defined microbial consortium consisting of three facultative anaerobes, Enterobacter cloacae IIT-BT 08, Citrobacter freundii IIT-BT L139 and Bacillus coagulans IIT-BT S1 was studied. In this investigation their individual and combinatorial H 2 production capabilities have been studied on defined media and pretreated sewage sludge. Defined medium, MYG (1% w/v Malt extract, 0.4% w/v yeast extract and 1% w/v glucose) with glucose as limiting substrate has been found to be most suitable for hydrogen production. Individually E. cloacae clearly gave higher yield (276 ml H 2 / g COD reduced) using defined medium than the other two strains. There was no considerable difference in maximal yield of hydrogen from individual and combinatorial (1:1:1 consortium) modes suggesting that E. cloacae dominated in the consortia on defined medium. Contradictorily, B. coagulans gave better bio-hydrogen yield (37.16 ml H 2 /g COD consumed) than the other two strains when activated sewage sludge was used as substrate. The pretreatment of sludge included sterilization, (15% v/v) dilution and supplementation with 0.5%w/v glucose which was found to be essential to screen out the hydrogen consuming bacteria and ameliorate the hydrogenation. Considering (1:1:1) consortium as inoculum, interestingly yield of hydrogen was recorded to increase to 41.23 ml H 2 / g COD reduced inferring that in consortium, the substrate utilization was significantly higher. The hydrogen yield from pretreated sludge obtained in this study (35.54 ml H 2 g sludge) has been found to be distinctively higher than the earlier reports (8.1 - 16.9 ml H 2 /g sludge). However it was lower compared to the yield obtained from co-digestion of (83:17) food waste and sewage sludge (122 ml H 2 /g carbohydrate COD). Employing formulated microbial consortia for bio-hydrogen production from sewage sludge was an attempt to augment the hydrogen yield from sludge. (authors)

  12. Feasibility of bio-hydrogen production from sewage sludge using defined microbial consortium

    International Nuclear Information System (INIS)

    Shireen Meher Kotay; Debabrata Das

    2006-01-01

    Biological hydrogen production potential of a defined microbial consortium consisting of three facultative anaerobes, Enterobacter cloacae IIT-BT 08, Citrobacter freundii IIT-BT L139 and Bacillus coagulans IIT-BT S1 was studied. In this investigation their individual and combinatorial H 2 production capabilities have been studied on defined media and pretreated sewage sludge. Defined medium, MYG (1% w/v Malt extract, 0.4% w/v yeast extract and 1% w/v glucose) with glucose as limiting substrate has been found to be most suitable for hydrogen production. Individually E. cloacae clearly gave higher yield (276 ml H 2 / g COD reduced) using defined medium than the other two strains. There was no considerable difference in maximal yield of hydrogen from individual and combinatorial (1:1:1 consortium) modes suggesting that E. cloacae dominated in the consortia on defined medium. Contradictorily, B. coagulans gave better bio-hydrogen yield (37.16 ml H 2 / g COD consumed) than the other two strains when activated sewage sludge was used as substrate. The pretreatment of sludge included sterilization, (15% v/v) dilution and supplementation with 0.5% w/v glucose which was found to be essential to screen out the hydrogen consuming bacteria and ameliorate the hydrogenation. Considering (1:1:1) consortium as inoculum, interestingly yield of hydrogen was recorded to increase to 41.23 ml H 2 / g COD reduced inferring that in consortium, the substrate utilization was significantly higher. The hydrogen yield from pretreated sludge obtained in this study (35.54 ml H 2 / g sludge) has been found to be distinctively higher than the earlier reports (8.1 - 16.9 ml H 2 / g sludge). However it was lower compared to the yield obtained from co-digestion of (83:17) food waste and sewage sludge (122 ml H 2 / g carbohydrate COD). Employing formulated microbial consortia for bio-hydrogen production from sewage sludge was an attempt to augment the hydrogen yield from sludge. (authors)

  13. Biogas production and methanogenic archaeal community in mesophilic and thermophilic anaerobic co-digestion processes.

    Science.gov (United States)

    Yu, D; Kurola, J M; Lähde, K; Kymäläinen, M; Sinkkonen, A; Romantschuk, M

    2014-10-01

    Over 258 Mt of solid waste are generated annually in Europe, a large fraction of which is biowaste. Sewage sludge is another major waste fraction. In this study, biowaste and sewage sludge were co-digested in an anaerobic digestion reactor (30% and 70% of total wet weight, respectively). The purpose was to investigate the biogas production and methanogenic archaeal community composition in the anaerobic digestion reactor under meso- (35-37 °C) and thermophilic (55-57 °C) processes and an increasing organic loading rate (OLR, 1-10 kg VS m(-3) d(-1)), and also to find a feasible compromise between waste treatment capacity and biogas production without causing process instability. In summary, more biogas was produced with all OLRs by the thermophilic process. Both processes showed a limited diversity of the methanogenic archaeal community which was dominated by Methanobacteriales and Methanosarcinales (e.g. Methanosarcina) in both meso- and thermophilic processes. Methanothermobacter was detected as an additional dominant genus in the thermophilic process. In addition to operating temperatures, the OLRs, the acetate concentration, and the presence of key substrates like propionate also affected the methanogenic archaeal community composition. A bacterial cell count 6.25 times higher than archaeal cell count was observed throughout the thermophilic process, while the cell count ratio varied between 0.2 and 8.5 in the mesophilic process. This suggests that the thermophilic process is more stable, but also that the relative abundance between bacteria and archaea can vary without seriously affecting biogas production. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Concomitant production of cellulase and xylanase by thermophilic mould Sporotrichum thermophile in solid state fermentation and their applicability in bread making.

    Science.gov (United States)

    Bala, Anju; Singh, Bijender

    2017-06-01

    Sporotrichum thermophile BJAMDU5 secreted high titres of xylanolytic and cellulolytic enzymes in solid state fermentation using mixture of wheat straw and cotton oil cake (ratio 1:1) at 45 °C, pH 5.0 after 72 h inoculated with 2.9 × 10 7  CFU/mL conidiospores. Supplementation of solid medium with lactose and ammonium sulphate further enhanced the production of hydrolytic enzymes. Among different surfactants studied, Tween 80 enhanced the production of all enzymes [3455 U/g DMR (dry mouldy residue), 879.26 U/g DMR, 976.28 U/g DMR and 35.10 U/g DMR for xylanase, CMCase (Carboxymethylcellulase), FPase (Filter paper activity) and β-glucosidase, respectively] as compared to other surfactants. Recycling of solid substrate reduced the production of all these enzymes after second cycle. End products analysis by TLC showed the ability of hydrolytic enzymes of S. thermophile to liberate monomeric (xylose and glucose) as well as oligomeric (xylobiose, cellobiose and higher ones) sugars. Supplementation of enzyme resulted in improved nutritional properties of the bread. Formation of oligomeric sugars by xylanase enzyme of S. thermophile BJAMDU5 make it a good candidate in food industry.

  15. Feasibility of biohydrogen production from industrial wastes using defined microbial co-culture

    Directory of Open Access Journals (Sweden)

    Peng Chen

    2015-01-01

    Full Text Available BACKGROUND: The development of clean or novel alternative energy has become a global trend that will shape the future of energy. In the present study, 3 microbial strains with different oxygen requirements, including Clostridium acetobutylicum ATCC 824, Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D, were used to construct a hydrogen production system that was composed of a mixed aerobic-facultative anaerobic-anaerobic consortium. The effects of metal ions, organic acids and carbohydrate substrates on this system were analyzed and compared using electrochemical and kinetic assays. It was then tested using small-scale experiments to evaluate its ability to convert starch in 5 L of organic wastewater into hydrogen. For the one-step biohydrogen production experiment, H1 medium (nutrient broth and potato dextrose broth was mixed directly with GAM broth to generate H2 medium (H1 medium and GAM broth. Finally, Clostridium acetobutylicum ATCC 824, Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D of three species microbial co-culture to produce hydrogen under anaerobic conditions. For the two-step biohydrogen production experiment, the H1 medium, after cultured the microbial strains Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D, was centrifuged to remove the microbial cells and then mixed with GAM broth (H2 medium. Afterward, the bacterial strain Clostridium acetobutylicum ATCC 824 was inoculated into the H2 medium to produce hydrogen by anaerobic fermentation. RESULTS: The experimental results demonstrated that the optimum conditions for the small-scale fermentative hydrogen production system were at pH 7.0, 35°C, a mixed medium, including H1 medium and H2 medium with 0.50 mol/L ferrous chloride, 0.50 mol/L magnesium sulfate, 0.50 mol/L potassium chloride, 1% w/v citric acid, 5% w/v fructose and 5% w/v glucose. The overall hydrogen production efficiency in the shake flask fermentation group was 33.7 m

  16. Production of α-amylase from some thermophilic Aspergillus species ...

    African Journals Online (AJOL)

    In this study, thermostable amylase activities of some thermophilic Aspergillus species were evaluated. The suitable medium and microorganisms for α-amylase synthesis were selected. Subsequently, the α-amylase activity of the microorganism was researched. In the measurements made on the 7th day of production on ...

  17. Thermodynamics and economic feasibility of acetone production from syngas using the thermophilic production host Moorella thermoacetica

    NARCIS (Netherlands)

    Redl, Stephanie; Sukumara, Sumesh; Ploeger, Tom; Wu, Liang; Ølshøj Jensen, Torbjørn; Nielsen, Alex Toftgaard; Noorman, H.J.

    2017-01-01

    Background: Syngas fermentation is a promising option for the production of biocommodities due to its abundance and compatibility with anaerobic fermentation. Using thermophilic production strains in a syngas fermentation process allows recovery of products with low boiling point from the off-gas

  18. Gas Fermentation using Thermophilic Moorella Species for production of Biochemicals

    DEFF Research Database (Denmark)

    Redl, Stephanie Maria Anna

    Gas fermentation is a promising technology which gained increasing attention over the last years. In this process, acetogenic bacteria convert gases rich in H2, CO2, and CO, into compounds of higher value. The gas can derive from industrial off-gas or from waste streams via gasification. In the gas...... fermentation processes that are nearly on commercial level, mesophilic acetogens are used to mainly produce ethanol and butanediol. However, thermophilic acetogens, such as Moorella thermoacetica would allow for easy downstream processing when producing volatile products such as acetone. This thesis starts...... with a review of the feedstock potential for gas fermentation and how thermophilic production strains as well as unconventional fermentation processes such as mixotrophy can help to exploit this potential. I analyzed a process with respect to thermodynamic and economic considerations, in which acetone...

  19. Improved cellulose conversion to bio-hydrogen with thermophilic bacteria and characterization of microbial community in continuous bioreactor

    International Nuclear Information System (INIS)

    Jiang, Hongyu; Gadow, Samir I.; Tanaka, Yasumitsu; Cheng, Jun; Li, Yu-You

    2015-01-01

    Thermophilic hydrogen fermentation of cellulose was evaluated by a long term continuous experiment and batch experiments. The continuous experiment was conducted under 55 °C using a continuously stirred tank reactor (CSTR) at a hydraulic retention time (HRT) of 10 day. A stable hydrogen yield of 15.4 ± 0.23 mol kg −1 of cellulose consumed was maintained for 190 days with acetate and butyrate as the main soluble byproducts. An analysis of the 16S rRNA sequences showed that the hydrogen-producing thermophilic cellulolytic microorganisms (HPTCM) were close to Thermoanaerobacterium thermosaccharolyticum, Clostridium sp. and Enterobacter cloacae. Batch experiment demonstrated that the highest H 2 producing activity was obtained at 55 °C and the ultimate hydrogen yield and the metabolic by-products were influenced greatly by temperatures. The effect of temperature variation showed that the activation energy for cellulose and glucose were estimated at 103 and 98.8 kJ mol −1 , respectively. - Highlights: • Continuous cellulosic-hydrogen fermentation was conducted at 55 °C. • Hydrogen yield was improved to 15.4 mol kg −1 of consumed-cellulose. • The cellulosic hydrogen bacteria were close to Clostridia and Enterobacter genus. • The mixed microflora produced H 2 within a wide range of temperatures (35 °C–65 °C). • Activation energy of cellulose and glucose were 103 and 98.8 kJ mol −1 , respectively

  20. Optimization of micronutrient supplement for enhancing biogas production from food waste in two-phase thermophilic anaerobic digestion.

    Science.gov (United States)

    Menon, Ajay; Wang, Jing-Yuan; Giannis, Apostolos

    2017-01-01

    The aim of this study was to enhance the biogas productivity of two-phase thermophilic anaerobic digestion (AD) using food waste (FW) as the primary substrate. The influence of adding four trace metals (Ca, Mg, Co, and Ni) as micronutrient supplement in the methanogenic phase of the thermophilic system was investigated. Initially, Response Surface Methodology (RSM) was applied to determine the optimal concentration of micronutrients in batch experiments. The results showed that optimal concentrations of 303, 777, 7 and 3mg/L of Ca, Mg, Co and Ni, respectively, increased the biogas productivity as much as 50% and significantly reduced the processing time. The formulated supplement was tested in continuous two-phase thermophilic AD system with regard to process stability and productivity. It was found that a destabilized thermophilic AD process encountering high VFA accumulation recovered in less than two weeks, while the biogas production was improved by 40% yielding 0.46L CH 4 /gVS added /day. There was also a major increase in soluble COD utilization upon the addition of micronutrient supplement. The results of this study indicate that a micronutrient supplement containing Ca, Mg, Co and Ni could probably remedy any type of thermophilic AD process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Ruminal microbe of biohydrogenation of trans-vaccenic acid to stearic acid in vitro

    Directory of Open Access Journals (Sweden)

    Li Dan

    2012-02-01

    Full Text Available Abstract Background Optimization of the unsaturated fatty acid composition of ruminant milk and meat is desirable. Alteration of the milk and fatty acid profile was previously attempted by the management of ruminal microbial biohydrogenation. The aim of this study was to identify the group of ruminal trans-vaccenic acid (trans-11 C18:1, t-VA hydrogenating bacteria by combining enrichment studies in vitro. Methods The enrichment culture growing on t-VA was obtained by successive transfers in medium containing t-VA. Fatty acids were detected by gas chromatograph and changes in the microbial composition during enrichment were analyzed by denaturing gradient gel electrophoresis (DGGE. Prominent DGGE bands of the enrichment cultures were identified by 16S rRNA gene sequencing. Results The growth of ruminal t-VA hydrogenating bacteria was monitored through the process of culture transfer according to the accumulation of stearic acid (C18:0, SA and ratio of the substrate (t-VA transformed to the product (SA. A significant part of the retrieved 16S rRNA gene sequences was most similar to those of uncultured bacteria. Bacteria corresponding to predominant DGGE bands in t-VA enrichment cultures clustered with t-VA biohydrogenated bacteria within Group B. Conclusions This study provides more insight into the pathway of biohydrogenation. It also may be important to control the production of t-VA, which has metabolic and physiological benefits, through management of ruminal biohydrogenation bacterium.

  2. Continuous biohydrogen production from fruit wastewater at low pH conditions.

    Science.gov (United States)

    Diamantis, Vasileios; Khan, Abid; Ntougias, Spyridon; Stamatelatou, Katerina; Kapagiannidis, Anastasios G; Aivasidis, Alexander

    2013-07-01

    Biohydrogen production from a simulated fruit wastewater (soluble COD = 3.17 ± 0.10 g L⁻¹) was carried out in a continuous stirred tank reactor (CSTR) of 2 L operational volume without biomass inoculation, heat pre-treatment or pH adjustment, resulting in a low operational pH (3.75 ± 0.09). The hydraulic retention time (HRT) varied from 15 to 5 h. A strong negative correlation (p CSTR was operated under the same HRT. The biogas hydrogen content was estimated as high as 55.8 ± 2.3 % and 55.4 ± 2.5 % at 25 and 30 °C, respectively. The main fermentation end products were acetic and butyric acids, followed by ethanol. Significant differences (p CSTR at 25 or 30 °C were identified for butyric acid at almost all HRTs examined. Simulation of the acidogenesis process in the CSTR (based on COD and carbon balances) indicated the possible metabolic compounds produced at 25 and 30 °C reactions and provided an adequate fit of the experimental data.

  3. Screening of thermotolerant and thermophilic fungi aiming β-xylosidase and arabinanase production.

    Science.gov (United States)

    Benassi, Vivian Machado; de Lucas, Rosymar Coutinho; Jorge, João Atílio; Polizeli, Maria de Lourdes Teixeira de Moraes

    2014-01-01

    Plant cell wall is mainly composed by cellulose, hemicellulose and lignin. The heterogeneous structure and composition of the hemicellulose are key impediments to its depolymerization and subsequent use in fermentation processes. Thus, this study aimed to perform a screening of thermophilic and thermotolerant filamentous fungi collected from different regions of the São Paulo state, and analyze the production of β-xylosidase and arabinanase at different temperatures. These enzymes are important to cell wall degradation and synthesis of end products as xylose and arabinose, respectively, which are significant sugars to fermentation and ethanol production. A total of 12 fungal species were analyzed and 9 of them grew at 45 °C, suggesting a thermophilic or thermotolerant character. Additionally Aspergillus thermomutatus anamorph of Neosartorya and A. parasiticus grew at 50 °C. Aspergillus niger and Aspergillus thermomutatus were the filamentous fungi with the most expressive production of β-xylosidase and arabinanase, respectively. In general for most of the tested microorganisms, β-xylosidase and arabinanase activities from mycelial extract (intracellular form) were higher in cultures grown at high temperatures (35-40 °C), while the correspondent extracellular activities were favorably secreted from cultures at 30 °C. This study contributes to catalogue isolated fungi of the state of São Paulo, and these findings could be promising sources for thermophilic and thermotolerant microorganisms, which are industrially important due to their enzymes.

  4. Ionic liquid-impregnated activated carbon for biohydrogen purification in an adsorption unit

    Science.gov (United States)

    Yusuf, N. Y.; Masdar, M. S.; Isahak, W. N. R. W.; Nordin, D.; Husaini, T.; Majlan, E. H.; Rejab, S. A. M.; Chew, C. L.

    2017-06-01

    Biological methods for hydrogen production (biohydrogen) are known as energy intensive and can be operated at ambient temperature and pressure; however, consecutive productions such as purification and separation processes still remain challenging in the industry. Various techniques are used to purify and separate hydrogen. These techniques include the use of sorbents/solvents, membranes and cryogenic distillation. In this study, carbon dioxide (CO2) was purified and separated from biohydrogen to produce high purity hydrogen gas. CO2 capture was studied using the activated carbon (AC) modified with the ionic liquid (IL) choline chloride as adsorbent. The physical and chemical properties of the adsorbents were characterized through XRD, FTIR, SEM-EDX, TGA, and BET analyses. The effects of IL loading, flow rate, temperature, and gas mixture were also investigated based on the absorption and desorption of CO2. The CO2 level in the biohydrogen composition was analyzed using a CO2 gas analyzer. The SEM image indicated that the IL homogeneously covered the AC surface. High IL dispersion inlet enhanced the capability of the adsorbent to capture CO2 gas. The thermal stability and presence of the functionalized group of ILs on AC were analyzed by TGA and FTIR techniques, respectively. CO2 adsorption experiments were conducted using a 1 L adsorber unit. Hence, adsorption technologies exhibit potential for biohydrogen purification and mainly affected by adsorbent ability and operating parameters. This research presents an improved biohydrogen technique based on adsorption technology with novel adsorbents. Two different types of commercial CO2 adsorbents were used in the experiment. Results show that the IL/AC exhibited properties suitable for CO2 adsorption. The IL/AC sample presented a high CO2 uptake of 30 wt. % IL when treated at 30 °C for 6 h under a flow rate of 1 L/min. The presence of IL increased the selectivity of CO2 removal during the adsorption process. This IL

  5. Production of biohydrogen by recombinant expression of [NiFe]-hydrogenase 1 in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Kim Jaoon YH

    2010-07-01

    Full Text Available Abstract Background Hydrogenases catalyze reversible reaction between hydrogen (H2 and proton. Inactivation of hydrogenase by exposure to oxygen is a critical limitation in biohydrogen production since strict anaerobic conditions are required. While [FeFe]-hydrogenases are irreversibly inactivated by oxygen, it was known that [NiFe]-hydrogenases are generally more tolerant to oxygen. The physiological function of [NiFe]-hydrogenase 1 is still ambiguous. We herein investigated the H2 production potential of [NiFe]-hydrogenase 1 of Escherichia coli in vivo and in vitro. The hyaA and hyaB genes corresponding to the small and large subunits of [NiFe]-hydrogenase 1 core enzyme, respectively, were expressed in BL21, an E. coli strain without H2 producing ability. Results Recombinant BL21 expressing [NiFe]-hydrogenase 1 actively produced H2 (12.5 mL H2/(h·L in 400 mL glucose minimal medium under micro-aerobic condition, whereas the wild type BL21 did not produce H2 even when formate was added as substrate for formate hydrogenlyase (FHL pathway. The majority of recombinant protein was produced as an insoluble form, with translocation of a small fraction to the membrane. However, the membrane fraction displayed high activity (~65% of total cell fraction, based on unit protein mass. Supplement of nickel and iron to media showed these metals contribute essentially to the function of [NiFe]-hydrogenase 1 as components of catalytic site. In addition, purified E. coli [NiFe]-hydrogenase 1 using his6-tag displayed oxygen-tolerant activity of ~12 nmol H2/(min·mg protein under a normal aeration environment, compared to [FeFe]-hydrogenase, which remains inactive under this condition. Conclusions This is the first report on physiological function of E. coli [NiFe]-hydrogenase 1 for H2 production. We found that [NiFe]-hydrogenase 1 has H2 production ability even under the existence of oxygen. This oxygen-tolerant property is a significant advantage because it is

  6. Production of D-xylanases by thermophilic fungi using different methods of culture

    Energy Technology Data Exchange (ETDEWEB)

    Grajek, W

    1986-01-01

    Seven thermophilic strains of fungi were examined for their ability to produce D-xylanase in liquid and solid-state fermentations. It was confirmed that the best producers of xylanase, among microorganisms used, were H. lanuginosa and S. thermophile in liquid fermentation, and T. aurantiacus and H. lanuginosa in solid-state fermentations. The higher productivity of xylanase, namely 18,72 IU/ml, was obtained in liquid culture of H. lanuginosa. The pH and temperature optima of enzymes from liquid and solid-state cultures of fungi used were also presented.

  7. Screening of thermotolerant and thermophilic fungi aiming β-xylosidase and arabinanase production

    Directory of Open Access Journals (Sweden)

    Vivian Machado Benassi

    2014-12-01

    Full Text Available Plant cell wall is mainly composed by cellulose, hemicellulose and lignin. The heterogeneous structure and composition of the hemicellulose are key impediments to its depolymerization and subsequent use in fermentation processes. Thus, this study aimed to perform a screening of thermophilic and thermotolerant filamentous fungi collected from different regions of the São Paulo state, and analyze the production of β-xylosidase and arabinanase at different temperatures. These enzymes are important to cell wall degradation and synthesis of end products as xylose and arabinose, respectively, which are significant sugars to fermentation and ethanol production. A total of 12 fungal species were analyzed and 9 of them grew at 45 ºC, suggesting a thermophilic or thermotolerant character. Additionally Aspergillus thermomutatus anamorph of Neosartorya and A. parasiticus grew at 50 ºC. Aspergillus niger and Aspergillus thermomutatus were the filamentous fungi with the most expressive production of β-xylosidase and arabinanase, respectively. In general for most of the tested microorganisms, β-xylosidase and arabinanase activities from mycelial extract (intracellular form were higher in cultures grown at high temperatures (35-40 ºC, while the correspondent extracellular activities were favorably secreted from cultures at 30 ºC. This study contributes to catalogue isolated fungi of the state of São Paulo, and these findings could be promising sources for thermophilic and thermotolerant microorganisms, which are industrially important due to their enzymes.

  8. Screening of thermotolerant and thermophilic fungi aiming β-xylosidase and arabinanase production

    Science.gov (United States)

    Benassi, Vivian Machado; de Lucas, Rosymar Coutinho; Jorge, João Atílio; Polizeli, Maria de Lourdes Teixeira de Moraes

    2014-01-01

    Plant cell wall is mainly composed by cellulose, hemicellulose and lignin. The heterogeneous structure and composition of the hemicellulose are key impediments to its depolymerization and subsequent use in fermentation processes. Thus, this study aimed to perform a screening of thermophilic and thermotolerant filamentous fungi collected from different regions of the São Paulo state, and analyze the production of β-xylosidase and arabinanase at different temperatures. These enzymes are important to cell wall degradation and synthesis of end products as xylose and arabinose, respectively, which are significant sugars to fermentation and ethanol production. A total of 12 fungal species were analyzed and 9 of them grew at 45 °C, suggesting a thermophilic or thermotolerant character. Additionally Aspergillus thermomutatus anamorph of Neosartorya and A. parasiticus grew at 50 °C. Aspergillus niger and Aspergillus thermomutatus were the filamentous fungi with the most expressive production of β-xylosidase and arabinanase, respectively. In general for most of the tested microorganisms, β-xylosidase and arabinanase activities from mycelial extract (intracellular form) were higher in cultures grown at high temperatures (35–40 °C), while the correspondent extracellular activities were favorably secreted from cultures at 30 °C. This study contributes to catalogue isolated fungi of the state of São Paulo, and these findings could be promising sources for thermophilic and thermotolerant microorganisms, which are industrially important due to their enzymes. PMID:25763055

  9. Biological hydrogen production by moderately thermophilic anaerobic bacteria

    International Nuclear Information System (INIS)

    HP Goorissen; AJM Stams

    2006-01-01

    This study focuses on the biological production of hydrogen at moderate temperatures (65-75 C) by anaerobic bacteria. A survey was made to select the best (moderate) thermophiles for hydrogen production from cellulolytic biomass. From this survey we selected Caldicellulosiruptor saccharolyticus (a gram-positive bacterium) and Thermotoga elfii (a gram-negative bacterium) as potential candidates for biological hydrogen production on mixtures of C 5 -C 6 sugars. Xylose and glucose were used as model substrates to describe growth and hydrogen production from hydrolyzed biomass. Mixed substrate utilization in batch cultures revealed differences in the sequence of substrate consumption and in catabolites repression of the two microorganisms. The regulatory mechanisms of catabolites repression in these microorganisms are not known yet. (authors)

  10. Biohydrogen production from renewable agri-waste blend: Optimization using mixer design

    Energy Technology Data Exchange (ETDEWEB)

    Prakasham, R.S.; Sathish, T.; Brahmaiah, P.; Subba Rao, Ch. [Bioengineering and Environmental Center, Indian Institute of Chemical Technology, Hyderabad 500 607 (India); Sreenivas Rao, R.; Hobbs, Phil J. [North-Wyke Research, Okehampton, Devon EX20 2SB (United Kingdom)

    2009-08-15

    Biohydrogen from untreated mixed renewable agri-waste using buffalo dung compost is reported. Corn husk (CH) supported 25% higher hydrogen (H{sub 2}) production and showed the maximum value (62.38%) with p value (1.2 x 10{sup -6}) revealing its significance at individual and interactive level, respectively, compared to ground nut shell (GNS) and rice husk (RH). Augmented-simplex-lattice design experimentation revealed that a partial supplementation of RH or GNS to CH improves H{sub 2} yield. Multiple-linear-regression analysis indicated that a quadratic model (low p = 0.0023, high F value = 35.99 and R{sup 2}{sub quadratic} = 0.99) was more significant compared to other (linear, cubic and special cubic) models. Acetate and butyrate were accounted >80% of the volatile fatty acids (VFAs). A maximum accumulation of 65.78 ml H{sub 2} g{sup -1} TVS was produced using agri-wastes in the ratio of CH:RH:GNS = 70:16:12. (author)

  11. Performance and microbial community analysis of two-stage process with extreme thermophilic hydrogen and thermophilic methane production from hydrolysate in UASB reactors

    DEFF Research Database (Denmark)

    Kongjan, Prawit; O-Thong, Sompong; Angelidaki, Irini

    2011-01-01

    The two-stage process for extreme thermophilic hydrogen and thermophilic methane production from wheat straw hydrolysate was investigated in up-flow anaerobic sludge bed (UASB) reactors. Specific hydrogen and methane yields of 89ml-H2/g-VS (190ml-H2/g-sugars) and 307ml-CH4/g-VS, respectively were...... energy of 13.4kJ/g-VS. Dominant hydrogen-producing bacteria in the H2-UASB reactor were Thermoanaerobacter wiegelii, Caldanaerobacter subteraneus, and Caloramator fervidus. Meanwhile, the CH4-UASB reactor was dominated with methanogens of Methanosarcina mazei and Methanothermobacter defluvii. The results...

  12. Biohydrogen production in the suspended and attached microbial growth systems from waste pastry hydrolysate.

    Science.gov (United States)

    Han, Wei; Hu, Yunyi; Li, Shiyi; Li, Feifei; Tang, Junhong

    2016-10-01

    Waste pastry was hydrolyzed by glucoamylase and protease which were obtained from solid state fermentation of Aspergillus awamori and Aspergillus oryzae to produce waste pastry hydrolysate. Then, the effects of hydraulic retention times (HRTs) (4-12h) on hydrogen production rate (HPR) in the suspended microbial growth system (continuous stirred tank reactor, CSTR) and attached microbial growth system (continuous mixed immobilized sludge reactor, CMISR) from waste pastry hydrolysate were investigated. The maximum HPRs of CSTR (201.8mL/(h·L)) and CMISR (255.3mL/(h·L)) were obtained at HRT of 6h and 4h, respectively. The first-order reaction could be used to describe the enzymatic hydrolysis of waste pastry. The carbon content of the waste pastry remained 22.8% in the undigested waste pastry and consumed 77.2% for carbon dioxide and soluble microbial products. To our knowledge, this is the first study which reports biohydrogen production from waste pastry. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Biohydrogen production from arabinose and glucose using extreme thermophilic anaerobic mixed cultures

    DEFF Research Database (Denmark)

    De Abreu, Angela Alexandra Valente; Karakashev, Dimitar Borisov; Angelidaki, Irini

    2012-01-01

    .0 LH2 L-1 d-1 and hydrogen yield of 1.10 and 0.75 molH2 mol-1substrate for Rarab and Rgluc, respectively). Lower hydrogen production in Rgluc was associated with higher lactate production. DGGE results revealed no significant difference on the bacterial community composition between operational periods...

  14. Production of Bioethanol From Lignocellulosic Biomass Using Thermophilic Anaerobic Bacteria

    DEFF Research Database (Denmark)

    Georgieva, Tania I.

    2006-01-01

    and xylose and to tolerate the inhibitory compounds present in lignocellulosic hydrolysates is therefore apparent. Several thermophilic anaerobic xylan degrading bacteria from our culture collection (EMB group at BioCentrum-DTU) have been screened for a potential ethanol producer from hemicellulose...... hydrolysates, and out of the screening test, one particular strain (A10) was selected for the best performance. The strain was morphologically and physiologically characterized as Thermoanaerobacter mathranii strain A10. Unlike other thermophilic anaerobic bacteria, the wild-type strain Thermoanaerobacter...... Thermoanaerobacter BG1L1 was further studied. The experiments were carried out in a continuous immobilized reactor system (a fluidized bed reactor), which is likely to be the process design configuration for xylose fermentation in a Danish biorefinery concept for production of fuel ethanol. The immobilization...

  15. Extremely Thermophilic Microorganisms as Metabolic Engineering Platforms for Production of Fuels and Industrial Chemicals

    Directory of Open Access Journals (Sweden)

    Benjamin M Zeldes

    2015-11-01

    Full Text Available Enzymes from extremely thermophilic microorganisms have been of technological interest for some time because of their ability to catalyze reactions of industrial significance at elevated temperatures. Thermophilic enzymes are now routinely produced in recombinant mesophilic hosts for use as discrete biocatalysts. Genome and metagenome sequence data for extreme thermophiles provide useful information for putative biocatalysts for a wide range of biotransformations, albeit involving at most a few enzymatic steps. However, in the past several years, unprecedented progress has been made in establishing molecular genetics tools for extreme thermophiles to the point that the use of these microorganisms as metabolic engineering platforms has become possible. While in its early days, complex metabolic pathways have been altered or engineered into recombinant extreme thermophiles, such that the production of fuels and chemicals at elevated temperatures has become possible. Not only does this expand the thermal range for industrial biotechnology, it also potentially provides biodiverse options for specific biotransformations unique to these microorganisms. The list of extreme thermophiles growing optimally between 70 and 100°C with genetic toolkits currently available includes archaea and bacteria, aerobes and anaerobes, coming from genera such as Caldicellulosiruptor, Sulfolobus, Thermotoga, Thermococcus and Pyrococcus. These organisms exhibit unusual and potentially useful native metabolic capabilities, including cellulose degradation, metal solubilization, and RuBisCO-free carbon fixation. Those looking to design a thermal bioprocess now have a host of potential candidates to choose from, each with its own advantages and challenges that will influence its appropriateness for specific applications. Here, the issues and opportunities for extremely thermophilic metabolic engineering platforms are considered with an eye towards potential technological

  16. Extremely thermophilic microorganisms as metabolic engineering platforms for production of fuels and industrial chemicals

    Science.gov (United States)

    Zeldes, Benjamin M.; Keller, Matthew W.; Loder, Andrew J.; Straub, Christopher T.; Adams, Michael W. W.; Kelly, Robert M.

    2015-01-01

    Enzymes from extremely thermophilic microorganisms have been of technological interest for some time because of their ability to catalyze reactions of industrial significance at elevated temperatures. Thermophilic enzymes are now routinely produced in recombinant mesophilic hosts for use as discrete biocatalysts. Genome and metagenome sequence data for extreme thermophiles provide useful information for putative biocatalysts for a wide range of biotransformations, albeit involving at most a few enzymatic steps. However, in the past several years, unprecedented progress has been made in establishing molecular genetics tools for extreme thermophiles to the point that the use of these microorganisms as metabolic engineering platforms has become possible. While in its early days, complex metabolic pathways have been altered or engineered into recombinant extreme thermophiles, such that the production of fuels and chemicals at elevated temperatures has become possible. Not only does this expand the thermal range for industrial biotechnology, it also potentially provides biodiverse options for specific biotransformations unique to these microorganisms. The list of extreme thermophiles growing optimally between 70 and 100°C with genetic toolkits currently available includes archaea and bacteria, aerobes and anaerobes, coming from genera such as Caldicellulosiruptor, Sulfolobus, Thermotoga, Thermococcus, and Pyrococcus. These organisms exhibit unusual and potentially useful native metabolic capabilities, including cellulose degradation, metal solubilization, and RuBisCO-free carbon fixation. Those looking to design a thermal bioprocess now have a host of potential candidates to choose from, each with its own advantages and challenges that will influence its appropriateness for specific applications. Here, the issues and opportunities for extremely thermophilic metabolic engineering platforms are considered with an eye toward potential technological advantages for high

  17. Biological hydrogen production from biomass by thermophilic bacteria

    International Nuclear Information System (INIS)

    Claassen, P.A.M.; Mars, A.E.; Budde, M.A.W.; Lai, M.; de Vrije, T.; van Niel, E.W.J.

    2006-01-01

    To meet the reduction of the emission of CO 2 imposed by the Kyoto protocol, hydrogen should be produced from renewable primary energy. Besides the indirect production of hydrogen by electrolysis using electricity from renewable resources, such as sunlight, wind and hydropower, hydrogen can be directly produced from biomass. At present, there are two strategies for the production of hydrogen from biomass: the thermochemical technology, such as gasification, and the biotechnological approach using micro-organisms. Biological hydrogen production delivers clean hydrogen with an environmental-friendly technology and is very suitable for the conversion of wet biomass in small-scale applications, thus having a high chance of becoming an economically feasible technology. Many micro-organisms are able to produce hydrogen from mono- and disaccharides, starch and (hemi)cellulose under anaerobic conditions. The anaerobic production of hydrogen is a common phenomenon, occurring during the process of anaerobic digestion. Here, hydrogen producing micro-organisms are in syn-trophy with methanogenic bacteria which consume the hydrogen as soon as it is produced. In this way, hydrogen production remains obscure and methane is the end-product. By uncoupling hydrogen production from methane production, hydrogen becomes available for recovery and exploitation. This study describes the use of extreme thermophilic bacteria, selected because of a higher hydrogen production efficiency as compared to mesophilic bacteria, for the production of hydrogen from renewable resources. As feedstock energy crops like Miscanthus and Sorghum bicolor and waste streams like domestic organic waste, paper sludge and potato steam peels were used. The feedstock was pretreated and/or enzymatically hydrolyzed prior to fermentation to make a fermentable substrate. Hydrogen production by Caldicellulosiruptor saccharolyticus, Thermotoga elfii and T. neapolitana on all substrates was observed. Nutrient

  18. Improving biogas production from anaerobic co-digestion of Thickened Waste Activated Sludge (TWAS) and fat, oil and grease (FOG) using a dual-stage hyper-thermophilic/thermophilic semi-continuous reactor.

    Science.gov (United States)

    Alqaralleh, Rania Mona; Kennedy, Kevin; Delatolla, Robert

    2018-07-01

    This paper investigates the feasibility and advantages of using a dual-stage hyper-thermophilic/thermophilic semi-continuous reactor system for the co-digestion of Thickened Waste Activated Sludge (TWAS) and Fat, Oil and Grease (FOG) to produce biogas in high quantity and quality. The performance of the dual-stage hyper-thermophilic (70°C)/thermophilic (55°C) anaerobic co-digestion system is evaluated and compared to the performance of a single-stage thermophilic (55°C) reactor that was used to co-digest the same FOG-TWAS mixtures. Both co-digestion reactors were compared to a control reactor (the control reactor was a single-stage thermophilic reactor that only digested TWAS). The effect of FOG% in the co-digestion mixture (based on total volatile solids) and the reactor hydraulic retention time (HRT) on the biogas/methane production and the reactors' performance were thoroughly investigated. The FOG% that led to the maximum methane yield with a stable reactor performance was determined for both reactors. The maximum FOG% obtained for the single-stage thermophilic reactor at 15 days HRT was found to be 65%. This 65% FOG resulted in 88.3% higher methane yield compared to the control reactor. However, the dual-stage hyper-thermophilic/thermophilic co-digestion reactor proved to be more efficient than the single-stage thermophilic co-digestion reactor, as it was able to digest up to 70% FOG with a stable reactor performance. The 70% FOG in the co-digestion mixture resulted in 148.2% higher methane yield compared to the control at 15 days HRT. 70% FOG (based on total volatile solids) is so far the highest FOG% that has been proved to be useful and safe for semi-continuous reactor application in the open literature. Finally, the dual-stage hyper-thermophilic/thermophilic co-digestion reactor also proved to be efficient and stable in co-digesting 40% FOG mixtures at lower HRTs (i.e., 9 and 12 days) and still produce high methane yields and Class A effluents

  19. Biohydrogen and Bioethanol Production from Biodiesel-Based Glycerol by Enterobacter aerogenes in a Continuous Stir Tank Reactor

    Directory of Open Access Journals (Sweden)

    Rujira Jitrwung

    2015-05-01

    Full Text Available Crude glycerol from the biodiesel manufacturing process is being produced in increasing quantities due to the expanding number of biodiesel plants. It has been previously shown that, in batch mode, semi-anaerobic fermentation of crude glycerol by Enterobacter aerogenes can produce biohydrogen and bioethanol simultaneously. The present study demonstrated the possible scaling-up of this process from small batches performed in small bottles to a 3.6-L continuous stir tank reactor (CSTR. Fresh feed rate, liquid recycling, pH, mixing speed, glycerol concentration, and waste recycling were optimized for biohydrogen and bioethanol production. Results confirmed that E. aerogenes uses small amounts of oxygen under semi-anaerobic conditions for growth before using oxygen from decomposable salts, mainly NH4NO3, under anaerobic condition to produce hydrogen and ethanol. The optimal conditions were determined to be 500 rpm, pH 6.4, 18.5 g/L crude glycerol (15 g/L glycerol and 33% liquid recycling for a fresh feed rate of 0.44 mL/min. Using these optimized conditions, the process ran at a lower media cost than previous studies, was stable after 7 days without further inoculation and resulted in yields of 0.86 mol H2/mol glycerol and 0.75 mol ethanol/mole glycerol.

  20. Biohydrogen and Bioethanol Production from Biodiesel-Based Glycerol by Enterobacter aerogenes in a Continuous Stir Tank Reactor

    Science.gov (United States)

    Jitrwung, Rujira; Yargeau, Viviane

    2015-01-01

    Crude glycerol from the biodiesel manufacturing process is being produced in increasing quantities due to the expanding number of biodiesel plants. It has been previously shown that, in batch mode, semi-anaerobic fermentation of crude glycerol by Enterobacter aerogenes can produce biohydrogen and bioethanol simultaneously. The present study demonstrated the possible scaling-up of this process from small batches performed in small bottles to a 3.6-L continuous stir tank reactor (CSTR). Fresh feed rate, liquid recycling, pH, mixing speed, glycerol concentration, and waste recycling were optimized for biohydrogen and bioethanol production. Results confirmed that E. aerogenes uses small amounts of oxygen under semi-anaerobic conditions for growth before using oxygen from decomposable salts, mainly NH4NO3, under anaerobic condition to produce hydrogen and ethanol. The optimal conditions were determined to be 500 rpm, pH 6.4, 18.5 g/L crude glycerol (15 g/L glycerol) and 33% liquid recycling for a fresh feed rate of 0.44 mL/min. Using these optimized conditions, the process ran at a lower media cost than previous studies, was stable after 7 days without further inoculation and resulted in yields of 0.86 mol H2/mol glycerol and 0.75 mol ethanol/mole glycerol. PMID:25970750

  1. Cellulosic ethanol production via consolidated bioprocessing by a novel thermophilic anaerobic bacterium isolated from a Himalayan hot spring.

    Science.gov (United States)

    Singh, Nisha; Mathur, Anshu S; Tuli, Deepak K; Gupta, Ravi P; Barrow, Colin J; Puri, Munish

    2017-01-01

    Cellulose-degrading thermophilic anaerobic bacterium as a suitable host for consolidated bioprocessing (CBP) has been proposed as an economically suited platform for the production of second-generation biofuels. To recognize the overall objective of CBP, fermentation using co-culture of different cellulolytic and sugar-fermenting thermophilic anaerobic bacteria has been widely studied as an approach to achieving improved ethanol production. We assessed monoculture and co-culture fermentation of novel thermophilic anaerobic bacterium for ethanol production from real substrates under controlled conditions. In this study, Clostridium sp. DBT-IOC-C19, a cellulose-degrading thermophilic anaerobic bacterium, was isolated from the cellulolytic enrichment cultures obtained from a Himalayan hot spring. Strain DBT-IOC-C19 exhibited a broad substrate spectrum and presented single-step conversion of various cellulosic and hemicellulosic substrates to ethanol, acetate, and lactate with ethanol being the major fermentation product. Additionally, the effect of varying cellulose concentrations on the fermentation performance of the strain was studied, indicating a maximum cellulose utilization ability of 10 g L -1 cellulose. Avicel degradation kinetics of the strain DBT-IOC-C19 displayed 94.6% degradation at 5 g L -1 and 82.74% degradation at 10 g L -1 avicel concentration within 96 h of fermentation. In a comparative study with Clostridium thermocellum DSM 1313, the ethanol and total product concentrations were higher by the newly isolated strain on pretreated rice straw at an equivalent substrate loading. Three different co-culture combinations were used on various substrates that presented two-fold yield improvement than the monoculture during batch fermentation. This study demonstrated the direct fermentation ability of the novel thermophilic anaerobic bacteria on various cellulosic and hemicellulosic substrates into ethanol without the aid of any exogenous enzymes

  2. Design of neural network model-based controller in a fed-batch microbial electrolysis cell reactor for bio-hydrogen gas production

    Science.gov (United States)

    Azwar; Hussain, M. A.; Abdul-Wahab, A. K.; Zanil, M. F.; Mukhlishien

    2018-03-01

    One of major challenge in bio-hydrogen production process by using MEC process is nonlinear and highly complex system. This is mainly due to the presence of microbial interactions and highly complex phenomena in the system. Its complexity makes MEC system difficult to operate and control under optimal conditions. Thus, precise control is required for the MEC reactor, so that the amount of current required to produce hydrogen gas can be controlled according to the composition of the substrate in the reactor. In this work, two schemes for controlling the current and voltage of MEC were evaluated. The controllers evaluated are PID and Inverse neural network (NN) controller. The comparative study has been carried out under optimal condition for the production of bio-hydrogen gas wherein the controller output is based on the correlation of optimal current and voltage to the MEC. Various simulation tests involving multiple set-point changes and disturbances rejection have been evaluated and the performances of both controllers are discussed. The neural network-based controller results in fast response time and less overshoots while the offset effects are minimal. In conclusion, the Inverse neural network (NN)-based controllers provide better control performance for the MEC system compared to the PID controller.

  3. Rumen Biohydrogenation and Microbial Community Changes Upon Early Life Supplementation of 22:6n-3 Enriched Microalgae to Goats

    Directory of Open Access Journals (Sweden)

    Lore Dewanckele

    2018-03-01

    Full Text Available Dietary supplementation of docosahexaenoic acid (DHA-enriched products inhibits the final step of biohydrogenation in the adult rumen, resulting in the accumulation of 18:1 isomers, particularly of trans(t-11 18:1. Occasionally, a shift toward the formation of t10 intermediates at the expense of t11 intermediates can be triggered. However, whether similar impact would occur when supplementing DHA-enriched products during pregnancy or early life remains unknown. Therefore, the current in vivo study aimed to investigate the effect of a nutritional intervention with DHA in the early life of goat kids on rumen biohydrogenation and microbial community. Delivery of DHA was achieved by supplementing DHA-enriched microalgae (DHA Gold either to the maternal diet during pregnancy (prenatal or to the diet of the young offspring (postnatal. At the age of 12 weeks, rumen fluid was sampled for analysis of long-chain fatty acids and microbial community based on bacterial 16S rRNA amplicon sequencing. Postnatal supplementation with DHA-enriched microalgae inhibited the final biohydrogenation step, as observed in adult animals. This resulted particularly in increased ruminal proportions of t11 18:1 rather than a shift to t10 intermediates, suggesting that both young and adult goats might be less prone to dietary induced shifts toward the formation of t10 intermediates, in comparison with cows. Although Butyrivibrio species have been identified as the most important biohydrogenating bacteria, this genus was more abundant when complete biohydrogenation, i.e. 18:0 formation, was inhibited. Blautia abundance was positively correlated with 18:0 accumulation, whereas Lactobacillus spp. Dialister spp. and Bifidobacterium spp. were more abundant in situations with greater t10 accumulation. Extensive comparisons made between current results and literature data indicate that current associations between biohydrogenation intermediates and rumen bacteria in young goats

  4. Hydrogen and methane production from desugared molasses using a two‐stage thermophilic anaerobic process

    DEFF Research Database (Denmark)

    Kongjan, Prawit; O-Thong, Sompong; Angelidaki, Irini

    2013-01-01

    Hydrogen and methane production from desugared molasses by a two‐stage thermophilic anaerobic process was investigated in a series of two up‐flow anaerobic sludge blanket (UASB) reactors. The first reactor that was dominated with hydrogen‐producing bacteria of Thermoanaerobacterium thermosaccharo......Hydrogen and methane production from desugared molasses by a two‐stage thermophilic anaerobic process was investigated in a series of two up‐flow anaerobic sludge blanket (UASB) reactors. The first reactor that was dominated with hydrogen‐producing bacteria of Thermoanaerobacterium...... molasses. Furthermore, the mixed gas with a volumetric content of 16.5% H2, 38.7% CO2, and 44.8% CH4, containing approximately 15% energy by hydrogen is viable to be bio‐hythane....

  5. Microbial conversion of food wastes for biofertilizer production with thermophilic lipolytic microbes

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Shu-Hsien; Yang, Shang-Shyng [Institute of Microbiology and Biochemistry, National Taiwan University, Taipei 10617, (Taiwan); Liu, Ching-Piao [Department of Biological Science and Technology, Meiho Institute of Technology, Pingtung 91201, (Taiwan)

    2007-05-15

    Food waste is approximately one quarter of the total garbage in Taiwan. To investigate the feasibility of microbial conversion of food waste to multiple functional biofertilizer, food waste was mixed with bulking materials, inoculated with thermophilic and lipolytic microbes and incubated at 50{sup o}C in a mechanical composter. Microbial inoculation enhanced the degradation of food wastes, increased the total nitrogen and the germination rate of alfalfa seed, shortened the maturity period and improved the quality of biofertilizer. In food waste inoculated with thermophilic and lipolytic Brevibacillus borstelensis SH168 for 28 days, total nitrogen increased from 2.01% to 2.10%, ash increased from 24.94% to 29.21%, crude fat decreased from 4.88% to 1.34% and the C/N ratio decreased from 18.02 to 17.65. Each gram of final product had a higher population of thermophilic microbes than mesophilic microbes. Microbial conversion of food waste to biofertilizer is a feasible and potential technology in the future to maintain the natural resources and to reduce the impact on environmental quality. (author)

  6. AnSBBR with circulation applied to biohydrogen production treating sucrose based wastewater: effects of organic loading, influent concentration and cycle length

    Directory of Open Access Journals (Sweden)

    D. A. Santos

    2014-09-01

    Full Text Available An anaerobic sequencing batch biofilm reactor (AnSBBR containing immobilized biomass and operating with recirculation of the liquid phase (total liquid volume 4.5 L; treated volume per cycle 1.9 L was used to treat sucrose-based wastewater at 30 ºC and produce biohydrogen. The influence of applied volumetric organic load was studied by varying the influent concentration at 3600 and 5400 mgCOD.L-1 and using cycle lengths of 4, 3 and 2 hours, obtaining in this manner volumetric organic loads of 9, 12, 13.5, 18 and 27 gCOD.L-1.d-1. Different performance indicators were used: productivity and yield of biohydrogen per applied and removed load, reactor stability and efficiency based on the applied and removed organic loads, both in terms of organic matter (measured as COD and carbohydrate (sucrose. The results revealed system stability (32-37% of H2 in biogas during biohydrogen production, as well as substrate consumption (12-19% COD; 97-99% sucrose. Conversion efficiencies decreased when the influent concentration was increased (at constant cycle length and when cycle lengths were reduced (at constant influent concentrations. The best yield was 4.16 mol-H2.kg-SUC-1 (sucrose load at 9 gCOD.L-1.d-1 (3600 mgCOD.L-1 and 4 h with H2 content in the biogas of 36% (64% CO2 and 0% CH4. However, the best specific molar productivity of hydrogen was 8.5 molH2.kgTVS-1.d-1 (32% H2; 68% CO2; 0% CH4, at 18 gCOD.L-1.d-1 (5400 mgCOD.L-1 and 3 h, indicating that the best productivity tends to occur at higher organic loads, as this parameter involves the "biochemical generation" of biogas, whereas the best yield tends to occur at lower and/or intermediate organic loads, as this parameter involves "biochemical consumption" of the substrate. The most significant metabolites were ethanol, acetic acid and butyric acid. Microbiological analyses revealed that the biomass contained bacilli and endospore filaments and showed no significant variations in morphology between

  7. Biohydrogen production from soluble condensed molasses fermentation using anaerobic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Lay, Chyi-How; Lin, Chiu-Yue [Department of Environmental Engineering and Science, Feng Chia University, Taichung 40724 (China); Wu, Jou-Hsien; Hsiao, Chin-Lang [Department of Water Resource Engineering, Feng Chia University (China); Chang, Jui-Jen [Department of Life Sciences, National Chung Hsing University (China); Chen, Chin-Chao [Environmental Resources Laboratory, Department of Landscape Architecture, Chungchou Institute of Technology (China)

    2010-12-15

    Using anaerobic micro-organisms to convert organic waste to produce hydrogen gas gives the benefits of energy recovery and environmental protection. The objective of this study was to develop a biohydrogen production technology from food wastewater focusing on hydrogen production efficiency and micro-flora community at different hydraulic retention times. Soluble condensed molasses fermentation (CMS) was used as the substrate because it is sacchariferous and ideal for hydrogen production. CMS contains nutrient components that are necessary for bacterial growth: microbial protein, amino acids, organic acids, vitamins and coenzymes. The seed sludge was obtained from the waste activated sludge from a municipal sewage treatment plant in Central Taiwan. This seed sludge was rich in Clostridium sp. A CSTR (continuously stirred tank reactor) lab-scale hydrogen fermentor (working volume, 4.0 L) was operated at a hydraulic retention time (HRT) of 3-24 h with an influent CMS concentration of 40 g COD/L. The results showed that the peak hydrogen production rate of 390 mmol H{sub 2}/L-d occurred at an organic loading rate (OLR) of 320 g COD/L-d at a HRT of 3 h. The peak hydrogen yield was obtained at an OLR of 80 g COD/L-d at a HRT of 12 h. At HRT 8 h, all hydrogenase mRNA detected were from Clostridium acetobutylicum-like and Clostridium pasteurianum-like hydrogen-producing bacteria by RT-PCR analysis. RNA based hydrogenase gene and 16S rRNA gene analysis suggests that Clostridium exists in the fermentative hydrogen-producing system and might be the dominant hydrogen-producing bacteria at tested HRTs (except 3 h). The hydrogen production feedstock from CMS is lower than that of sucrose and starch because CMS is a waste and has zero cost, requiring no added nutrients. Therefore, producing hydrogen from food wastewater is a more commercially feasible bioprocess. (author)

  8. In vitro production of thymine dimer by ultroviolet irradiation of DNA from mesophilic and thermophilic bacteria

    International Nuclear Information System (INIS)

    Yein, F.S.; Stenesh, J.

    1989-01-01

    Thymine dimer was produced in vitro by ultraviolet irradiation of DNA, isolated from the mesophile Bacillus licheniformis and the thermophile B. stearothermophilus. Irradiation was performed at three different temperaturs (35, 45 and 55 C) and the thymine dimer was isolated and determined. An HPLC procedure was developed that permitted temperature was greater for the thermophile than for the mesophile. Formation of thymine dimer increased with temperature for both organisms but more so for the thermophile; over the temperature range of 35-55 C, the average increase in thymine dimer production for the themrophile was about 4-times that for the mesophile. The melting out temperature, as a function of increasing irradiation temperature, was essentially unchanged for the mesophilic DNA, but decreased progressively for the thermophilic DNA. These results are discussed in terms of the macromolecular theory of to the macromolecular theory of the thermophily. (author). 31 refs.; 4 figs.; 3 tabs

  9. Continuous biohydrogen production using cheese whey: Improving the hydrogen production rate

    Energy Technology Data Exchange (ETDEWEB)

    Davila-Vazquez, Gustavo; Cota-Navarro, Ciria Berenice; Razo-Flores, Elias [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Lomas 4a seccion, C.P. 78216, San Luis Potosi, S.L.P (Mexico); Rosales-Colunga, Luis Manuel; de Leon-Rodriguez, Antonio [Division de Biologia Molecular, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Lomas 4a seccion, C.P. 78216, San Luis Potosi, S.L.P (Mexico)

    2009-05-15

    Due to the renewed interest in finding sustainable fuels or energy carriers, biohydrogen (Bio-H{sub 2}) from biomass is a promising alternative. Fermentative Bio-H{sub 2} production was studied in a continuous stirred tank reactor (CSTR) operated during 65.6 d with cheese whey (CW) as substrate. Three hydraulic retention times (HRTs) were tested (10, 6 and 4 h) and the highest volumetric hydrogen production rate (VHPR) was attained with HRT of 6 h. Therefore, four organic loading rates (OLRs) at a fixed HRT of 6 h were tested thereafter, being: 92.4, 115.5, 138.6 and 184.4 g lactose/L/d. The highest VHPR (46.61 mmol H{sub 2}/L/h) and hydrogen molar yield (HMY) of 2.8 mol H{sub 2}/mol lactose were found at an OLR of 138.6 g lactose/L/d; a sharp fall in VHPR occurred at an OLR of 184.4 g lactose/L/d. Butyric, propionic and acetic acids were the main soluble metabolites found, with butyric-to-acetic ratios ranging from 1.0 to 2.4. Bacterial community was identified by partial sequence analysis of the 16S rRNA and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The results showed that at HRT of 10 h and 6 h were dominated by the Clostridium genus. The VHPR attained in this study is the highest reported value for a CSTR system using CW as substrate with anaerobic sludge as inoculum and represents a 33-fold increase compared to a previous study. Thus, it was demonstrated that continuous fermentative Bio-H{sub 2} production from CW can be significantly enhanced by an appropriate selection of parameters such as HRT and OLR. Enhancements in VHPR are significant because it is a critical parameter to determine the full-scale practical application of fermentation technologies that will be used for sustainable and clean energy generation. (author)

  10. An integrated green process: Subcritical water, enzymatic hydrolysis, and fermentation, for biohydrogen production from coconut husk.

    Science.gov (United States)

    Muharja, Maktum; Junianti, Fitri; Ranggina, Dian; Nurtono, Tantular; Widjaja, Arief

    2018-02-01

    The objective of this work is to develop an integrated green process of subcritical water (SCW), enzymatic hydrolysis and fermentation of coconut husk (CCH) to biohydrogen. The maximum sugar yield was obtained at mild severity factor. This was confirmed by the degradation of hemicellulose, cellulose and lignin. The tendency of the changing of sugar yield as a result of increasing severity factor was opposite to the tendency of pH change. It was found that CO 2 gave a different tendency of severity factor compared to N 2 as the pressurizing gas. The result of SEM analysis confirmed the structural changes during SCW pretreatment. This study integrated three steps all of which are green processes which ensured an environmentally friendly process to produce a clean biohydrogen. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Improved production of biohydrogen in light-powered Escherichia coli by co-expression of proteorhodopsin and heterologous hydrogenase

    Directory of Open Access Journals (Sweden)

    Kim Jaoon YH

    2012-01-01

    Full Text Available Abstract Background Solar energy is the ultimate energy source on the Earth. The conversion of solar energy into fuels and energy sources can be an ideal solution to address energy problems. The recent discovery of proteorhodopsin in uncultured marine γ-proteobacteria has made it possible to construct recombinant Escherichia coli with the function of light-driven proton pumps. Protons that translocate across membranes by proteorhodopsin generate a proton motive force for ATP synthesis by ATPase. Excess protons can also be substrates for hydrogen (H2 production by hydrogenase in the periplasmic space. In the present work, we investigated the effect of the co-expression of proteorhodopsin and hydrogenase on H2 production yield under light conditions. Results Recombinant E. coli BL21(DE3 co-expressing proteorhodopsin and [NiFe]-hydrogenase from Hydrogenovibrio marinus produced ~1.3-fold more H2 in the presence of exogenous retinal than in the absence of retinal under light conditions (70 μmole photon/(m2·s. We also observed the synergistic effect of proteorhodopsin with endogenous retinal on H2 production (~1.3-fold more with a dual plasmid system compared to the strain with a single plasmid for the sole expression of hydrogenase. The increase of light intensity from 70 to 130 μmole photon/(m2·s led to an increase (~1.8-fold in H2 production from 287.3 to 525.7 mL H2/L-culture in the culture of recombinant E. coli co-expressing hydrogenase and proteorhodopsin in conjunction with endogenous retinal. The conversion efficiency of light energy to H2 achieved in this study was ~3.4%. Conclusion Here, we report for the first time the potential application of proteorhodopsin for the production of biohydrogen, a promising alternative fuel. We showed that H2 production was enhanced by the co-expression of proteorhodopsin and [NiFe]-hydrogenase in recombinant E. coli BL21(DE3 in a light intensity-dependent manner. These results demonstrate that E. coli

  12. Continuous cultivation of a thermophilic bacterium Aeribacillus pallidus 418 for production of an exopolysaccharide applicable in cosmetic creams.

    Science.gov (United States)

    Radchenkova, N; Panchev, I; Vassilev, S; Kuncheva, M; Dobreva, S; Kambourova, M

    2015-11-01

    The aim of this study was to evaluate the effectiveness of continuous cultivation approach for exopolysaccharide (EPS) production by a thermophilic micro-organism and the potential of the synthesized EPS for application in cosmetic industry. Study on the ability of Aeribacillus pallidus 418, isolated as a good EPS producer, to synthesize the polymer in continuous cultures showed higher production in comparison with batch cultures. The degree of the EPS in the precipitate after continuous cultivation significantly increased. Non-Newtonian pseudoplastic and thixotropic behaviour of EPS determines the ability of the received cream to become more fluid after increasing time of application on the skin. This study demonstrates a highly efficient way for production of EPS from a continuous growth culture of A. pallidus 418 that have many advantages and can outperform batch culture by eliminating time for cleaning and sterilization of the vessel and the comparatively long lag phases before the organisms enter a brief period of high productivity. The valuable physico-chemical properties of the synthesized EPS influenced positively the properties of a commercial cream. EPSs from thermophilic micro-organisms are of special interest due to the advantages of the thermophilic processes and nonpathogenic nature of the polymer molecules. However, their industrial application is hindered by the comparatively low biomass and correspondingly EPS yield. Suggested continuous approach for EPS could have an enormous economic potential for an industrial scale production of thermophilic EPSs. © 2015 The Society for Applied Microbiology.

  13. Biological production of hydrogen from agricultural raw materials and residues with a subsequent methanisation step; Biologische Wasserstoffproduktion aus landwirtschaftlichen Roh- und Reststoffen mit nachfolgender Methanstufe

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, M.; Stegmann, R. [Technische Univ. Hamburg-Harburg, Hamburg (Germany). Inst. fuer AbfallRessourcenWirtschaft

    2007-07-01

    In order to examine the thermophile fermentative production from biohydrogen, discontinuous attempts were accomplished at a temperature of 60 C. As an inoculum, heat-treated sewage sludge was used. Glucose was used as a substrate. The fermenting residues of the hydrogen attempts were used as a substrate in a methane reactor in order to examine a two-stage system. The hydrogen attempts in the anaerobic test system were operated with a hydraulic retention time by 3.3 days and were performed during a period of 300 days. The optimal space load amounts to 5 g (l*d). The production rate at hydrogen amounts to 1.2 Nl/(l{sub R}*d). The yields amount to between 200 and 250 Nml/g oTS. In the case of an overloading of the system with substrate, the hydrogen production decreases drastically due to poor yields. Biological hydrogen production by fermentation possesses the potential to become a component for a lasting emission-free power supply. The thermophile approach ensures a simultaneous hygienization. As a fermenting remainder treatment a downstream methanation stage is possible.

  14. Enhanced Bio-hydrogen Production from Protein Wastewater by Altering Protein Structure and Amino Acids Acidification Type

    Science.gov (United States)

    Xiao, Naidong; Chen, Yinguang; Chen, Aihui; Feng, Leiyu

    2014-01-01

    Enhanced bio-hydrogen production from protein wastewater by altering protein structure and amino acids acidification type via pH control was investigated. The hydrogen production reached 205.2 mL/g-protein when protein wastewater was pretreated at pH 12 and then fermented at pH 10. The mechanism studies showed that pH 12 pretreatment significantly enhanced protein bio-hydrolysis during the subsequent fermentation stage as it caused the unfolding of protein, damaged the protein hydrogen bonding networks, and destroyed the disulfide bridges, which increased the susceptibility of protein to protease. Moreover, pH 10 fermentation produced more acetic but less propionic acid during the anaerobic fermentation of amino acids, which was consistent with the theory of fermentation type affecting hydrogen production. Further analyses of the critical enzymes, genes, and microorganisms indicated that the activity and abundance of hydrogen producing bacteria in the pH 10 fermentation reactor were greater than those in the control. PMID:24495932

  15. Enhanced bio-hydrogen production from protein wastewater by altering protein structure and amino acids acidification type.

    Science.gov (United States)

    Xiao, Naidong; Chen, Yinguang; Chen, Aihui; Feng, Leiyu

    2014-02-05

    Enhanced bio-hydrogen production from protein wastewater by altering protein structure and amino acids acidification type via pH control was investigated. The hydrogen production reached 205.2 mL/g-protein when protein wastewater was pretreated at pH 12 and then fermented at pH 10. The mechanism studies showed that pH 12 pretreatment significantly enhanced protein bio-hydrolysis during the subsequent fermentation stage as it caused the unfolding of protein, damaged the protein hydrogen bonding networks, and destroyed the disulfide bridges, which increased the susceptibility of protein to protease. Moreover, pH 10 fermentation produced more acetic but less propionic acid during the anaerobic fermentation of amino acids, which was consistent with the theory of fermentation type affecting hydrogen production. Further analyses of the critical enzymes, genes, and microorganisms indicated that the activity and abundance of hydrogen producing bacteria in the pH 10 fermentation reactor were greater than those in the control.

  16. The Feasibility of Thermophilic Caldimonas manganoxidans as a Platform for Efficient PHB Production.

    Science.gov (United States)

    Hsiao, Li-Jung; Lin, Ji-Hong; Sankatumvong, Pantitra; Wu, Tzong-Ming; Li, Si-Yu

    2016-11-01

    Recently, poly(3-hydroxybutyrate) (PHB) has been found in a few thermophilic strains where several advantages can be gained from running fermentation at high temperatures. Caldimonas manganoxidans, a thermophilic gram-negative bacterium, was investigated for the feasibility as a PHB-producing strain. It is suggested that the best fermentation strategy for achieving the highest PHB concentration of 5.4 ± 1.1 g/L (from 20 g/L glucose) in 24 h is to use the fermentation conditions that are favored for the bacterial growth, yet temperature and pH should be chosen at conditions that are favored for the PHB content. Besides, the above fermentation conditions produce PHB that has a high molecular weight of 1274 kDa with a low polydispersity index (PDI) of 1.45, where the highest Mw of PHB of 1399 kDa (PDI of 1.32) is obtained in this study. To the best knowledge of authors, C. manganoxidans has the best PHB productivity among the thermophiles and is comparable to those common PHB-producing mesophiles.

  17. (Hyper)thermophilic Enzymes: Production and Purification

    NARCIS (Netherlands)

    Falcicchio, P.; Levisson, M.; Kengen, S.W.M.; Koutsopoulos, S.

    2014-01-01

    The discovery of thermophilic and hyperthermophilic microorganisms, thriving at environmental temperatures near or above 100 °C, has revolutionized our ideas about the upper temperature limit at which life can exist. The characterization of (hyper)thermostable proteins has broadened our

  18. Mesophilic and thermophilic alkaline fermentation of waste activated sludge for hydrogen production: Focusing on homoacetogenesis

    DEFF Research Database (Denmark)

    Wan, Jingjing; Jing, Yuhang; Zhang, Shicheng

    2016-01-01

    The present study compared the mesophilic and thermophilic alkaline fermentation of waste activated sludge (WAS) for hydrogen production with focus on homoacetogenesis, which mediated the consumption of H2 and CO2 for acetate production. Batch experiments showed that hydrogen yield of WAS increased...

  19. Hydrogen production by hyperthermophilic and extremely thermophilic bacteria and archaea: mechanisms for reductant disposal.

    Science.gov (United States)

    Verhaart, Marcel R A; Bielen, Abraham A M; van der Oost, John; Stams, Alfons J M; Kengen, Servé W M

    2010-01-01

    Hydrogen produced from biomass by bacteria and archaea is an attractive renewable energy source. However, to make its application more feasible, microorganisms are needed with high hydrogen productivities. For several reasons, hyperthermophilic and extremely thermophilic bacteria and archaea are promising is this respect. In addition to the high polysaccharide-hydrolysing capacities of many of these organisms, an important advantage is their ability to use most of the reducing equivalents (e.g. NADH, reduced ferredoxin) formed during glycolysis for the production of hydrogen, enabling H2/hexose ratios of between 3.0 and 4.0. So, despite the fact that the hydrogen-yielding reactions, especially the one from NADH, are thermodynamically unfavourable, high hydrogen yields are obtained. In this review we focus on three different mechanisms that are employed by a few model organisms, viz. Caldicellulosiruptor saccharolyticus and Thermoanaerobacter tengcongensis, Thermotoga maritima, and Pyrococcus furiosus, to efficiently produce hydrogen. In addition, recent developments to improve hydrogen production by hyperthermophilic and extremely thermophilic bacteria and archaea are discussed.

  20. Evaluation and simultaneous optimization of bio-hydrogen production using 3 2 factorial design and the desirability function

    Science.gov (United States)

    Cuetos, M. J.; Gómez, X.; Escapa, A.; Morán, A.

    Various mixtures incorporating a simulated organic fraction of municipal solid wastes and blood from a poultry slaughterhouse were used as substrate in a dark fermentation process for the production of hydrogen. The individual and interactive effects of hydraulic retention time (HRT), solid content in the feed (%TS) and proportion of residues (%Blood) on bio-hydrogen production were studied in this work. A central composite design and response surface methodology were employed to determine the optimum conditions for the hydrogen production process. Experimental results were approximated to a second-order model with the principal effects of the three factors considered being statistically significant (P < 0.05). The production of hydrogen obtained from the experimental point at conditions close to best operability was 0.97 L Lr -1 day -1. Moreover, a desirability function was employed in order to optimize the process when a second, methanogenic, phase is coupled with it. In this last case, the optimum conditions lead to a reduction in the production of hydrogen when the optimization process involves the maximization of intermediary products.

  1. Electricity production and microbial characterization of thermophilic microbial fuel cells.

    Science.gov (United States)

    Dai, Kun; Wen, Jun-Li; Zhang, Fang; Ma, Xi-Wen; Cui, Xiang-Yu; Zhang, Qi; Zhao, Ting-Jia; Zeng, Raymond J

    2017-11-01

    Thermophilic microbial fuel cell (TMFC) offers many benefits, but the investigations on the diversity of exoelectrogenic bacteria are scarce. In this study, a two-chamber TMFC was constructed using ethanol as an electron donor, and the microbial dynamics were analyzed by high-throughput sequencing and 16S rRNA clone-library sequencing. The open-circuit potential of TMFC was approximately 650mV, while the maximum voltage was around 550mV. The maximum power density was 437mW/m 2 , and the columbic efficiency in this work was 20.5±6.0%. The Firmicutes bacteria, related to the uncultured bacterium clone A55_D21_H_B_C01 with a similarity of 99%, accounted for 90.9% of all bacteria in the TMFC biofilm. This unknown bacterium has the potential to become a new thermophilic exoelectrogenic bacterium that is yet to be cultured. The development of TMFC-involved biotechnologies will be beneficial for the production of valuable chemicals and generation of energy in the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Hydrogen production by hyperthermophilic and extremely thermophilic bacteria and archaea: mechanisms for reductant disposal

    NARCIS (Netherlands)

    Verhaart, M.R.A.; Bielen, A.A.M.; Oost, van der J.; Stams, A.J.M.; Kengen, S.W.M.

    2010-01-01

    Hydrogen produced from biomass by bacteria and archaea is an attractive renewable energy source. However, to make its application more feasible, microorganisms are needed with high hydrogen productivities. For several reasons, hyperthermophilic and extremely thermophilic bacteria and archaea are

  3. Production of Sporotrichum thermophile xylanase by solid state fermentation utilizing deoiled Jatropha curcas seed cake and its application in xylooligosachharide synthesis.

    Science.gov (United States)

    Sadaf, Ayesha; Khare, S K

    2014-02-01

    De-oiled Jatropha curcas seed cake, a plentiful by-product of biodiesel industry was used as substrate for the production of a useful xylanase from Sporotrichum thermophile in solid state fermentation. Under the optimized conditions, 1025U xylanase/g (deoiled seed cake) was produced. The xylanase exhibited half life of 4h at 45°C and 71.44min at 50°C respectively. It was stable in a broad pH range of 7.0-11.0. Km and Vmax were 12.54mg/ml and 454.5U/ml/min respectively. S. thermophile xylanase is an endoxylanase free of exoxylanase activity, hence advantageous for xylan hydrolysis to produce xylooligosachharides. Hydrolysis of oat spelt xylan by S. thermophile xylanase yielded 73% xylotetraose, 15.4% xylotriose and 10% xylobiose. The S. thermophile endoxylanase thus seem potentially useful in the food industries. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Exploring optimal conditions for thermophilic fermentative hydrogen production from cassava stillage

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Gang; Zou, Zhonghai; Wang, Wen [Key Laboratory of Yangtze River Water Environment, Ministry(Tongji University), Siping Road no 1239, Shanghai 200092 (China); Xie, Li; Zhou, Qi [Key Laboratory of Yangtze River Water Environment, Ministry(Tongji University), Siping Road no 1239, Shanghai 200092 (China); UNEP-Tongji University Institute of Environment for Sustainable Development, Siping Road no 1239, Shanghai 200092 (China)

    2010-06-15

    This study investigated the effects of seed sludges, alkalinity and HRT on the thermophilic fermentative hydrogen production from cassava stillage. Five different kinds of sludges were used as inocula without any pretreatment. Though batch experiments showed that mesophilic anaerobic sludge was the best inoculum, the hydrogen yields with different seed sludges were quite similar in continuous experiments in the range of 82.9-92.3 ml H{sub 2}/gVS without significant differences which could be attributed to the establishment of Uncultured Thermoanaerobacteriaceae bacterium-dominant microbial communities in all reactors. It is indicated that results obtained from batch experiments are not consistent with those from continuous experiments and all the tested seed sludges are good sources for continuous thermophilic hydrogen production from cassava stillage. The influent alkalinity of 6 g NaHCO{sub 3}/L and HRT 24 h were optimal for hydrogen production with hydrogen yield of 76 ml H{sub 2}/gVS and hydrogen production rate of 3215 ml H{sub 2}/L/d. Butyrate was the predominant metabolite in all experiments. With the increase in alkalinity of more than 6 g/L, the concentration of VFA/ethanol increased while hydrogen yield decreased due to the higher concentration of acetate and propionate. The decrease in HRT resulted in the higher hydrogen production rate but lower hydrogen yield. Variation of hydrogen yields were quite correlated with butyrate/acetate (B/A) ratio with different influent alkalinities, however, butyrate was important parameter to justify the hydrogen yields with various HRTs. (author)

  5. Biohydrogen production by dark fermentation of glycerol using Enterobacter and Citrobacter Sp.

    Science.gov (United States)

    Maru, Biniam T; Constanti, Magda; Stchigel, Alberto M; Medina, Francesc; Sueiras, Jesus E

    2013-01-01

    Glycerol is an attractive substrate for biohydrogen production because, in theory, it can produce 3 mol of hydrogen per mol of glycerol. Moreover, glycerol is produced in substantial amounts as a byproduct of producing biodiesel, the demand for which has increased in recent years. Therefore, hydrogen production from glycerol was studied by dark fermentation using three strains of bacteria: namely, Enterobacter spH1, Enterobacter spH2, and Citrobacter freundii H3 and a mixture thereof (1:1:1). It was found that, when an initial concentration of 20 g/L of glycerol was used, all three strains and their mixture produced substantial amounts of hydrogen ranging from 2400 to 3500 mL/L, being highest for C. freundii H3 (3547 mL/L) and Enterobacter spH1 (3506 mL/L). The main nongaseous fermentation products were ethanol and acetate, albeit in different ratios. For Enterobacter spH1, Enterobacter spH2, C. freundii H3, and the mixture (1:1:1), the ethanol yields (in mol EtOH/mol glycerol consumed) were 0.96, 0.67, 0.31, and 0.66, respectively. Compared to the individual strains, the mixture (1:1:1) did not show a significantly higher hydrogen level, indicating that there was no synergistic effect. Enterobacter spH1 was selected for further investigation because of its higher yield of hydrogen and ethanol. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

  6. Biohydrogen Production from Hydrolysates of Selected Tropical Biomass Wastes with Clostridium Butyricum

    Science.gov (United States)

    Dan Jiang; Fang, Zhen; Chin, Siew-Xian; Tian, Xiao-Fei; Su, Tong-Chao

    2016-06-01

    Biohydrogen production has received widespread attention from researchers in industry and academic fields. Response surface methodology (RSM) was applied to evaluate the effects of several key variables in anaerobic fermentation of glucose with Clostridium butyrium, and achieved the highest production rate and yield of hydrogen. Highest H2 yield of 2.02 mol H2/mol-glucose was achieved from 24 h bottle fermentation of glucose at 35 °C, while the composition of medium was (g/L): 15.66 glucose, 6.04 yeast extract, 4 tryptone, 3 K2HPO4, 3 KH2PO4, 0.05 L-cysteine, 0.05 MgSO4·7H2O, 0.1 MnSO4·H2O and 0.3 FeSO4·7H2O, which was very different from that for cell growth. Sugarcane bagasse and Jatropha hulls were selected as typical tropical biomass wastes to produce sugars via a two-step acid hydrolysis for hydrogen production. Under the optimized fermentation conditions, H2 yield (mol H2/mol-total reducing sugar) was 2.15 for glucose, 2.06 for bagasse hydrolysate and 1.95 for Jatropha hull hydrolysate in a 3L fermenter for 24 h at 35 °C, with H2 purity of 49.7-64.34%. The results provide useful information and basic data for practical use of tropical plant wastes to produce hydrogen.

  7. Efficient production of 2,3-butanediol from corn stover hydrolysate by using a thermophilic Bacillus licheniformis strain.

    Science.gov (United States)

    Li, Lixiang; Li, Kun; Wang, Kai; Chen, Chao; Gao, Chao; Ma, Cuiqing; Xu, Ping

    2014-10-01

    In this study, a thermophilic Bacillus licheniformis strain X10 was newly isolated for 2,3-butanediol (2,3-BD) production from lignocellulosic hydrolysate. Strain X10 could utilize glucose and xylose simultaneously without carbon catabolite repression. In addition, strain X10 possesses high tolerance to fermentation inhibitors including furfural, vanillin, formic acid, and acetic acid. In a fed-batch fermentation, 74.0g/L of 2,3-BD was obtained from corn stover hydrolysate, with a productivity of 2.1g/Lh and a yield of 94.6%. Thus, this thermophilic B. licheniformis strain is a candidate for the development of efficient industrial production of 2,3-BD from corn stover hydrolysate. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Production and partial characterisation of feruloyl esterase by Sporotrichum thermophile in solid-state fermentation

    DEFF Research Database (Denmark)

    Topakas, E.; Kalogeris, E.; Kekos, D.

    2003-01-01

    A number of factors affecting production of feruloyl esterase an enzyme that hydrolyse ester linkages of ferulic acid (FA) in plant cell walls, by the thermophylic fungus Sporotrichum thermophile under solid state fermentation (SSF) were investigated. Initial moisture content and type of carbon...

  9. Comparative studies on the production of cellulases by thermophilic fungi in submerged and solid-state fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Grajek, W

    1987-05-01

    Six thermophilic fungi were examined for their ability to produce cellulolytic enzymes in liquid (LF) and solid-state fermentation (SSF). The best cellulase activities were achieved by Thermoascus aurantiacus and Sporotrichum thermophile. Taking into consideration that solid-state medium obtained from 100 g of dry sugar-beet pulp occupies about 1 l of fermentor volume equivalent to 1 l of LF, it was confirmed that enzyme productivity per unit volume from both fungi was greater in SSF than in LF. The cellulase system obtained by SSF with T. aurantiacus contained 1.322 IU/l of exo-..beta..-D-glucanase, 53.269 IU/l of endo-..beta..-D-glucanase and 8.974 IU/l of ..beta..-D-glucosidase. The thermal and pH characteristics of cellulases from solid-state fermentation of T. aurantiacus and S. thermophile are described.

  10. Optimization studies of bio-hydrogen production in a coupled microbial electrolysis-dye sensitized solar cell system.

    Science.gov (United States)

    Ajayi, Folusho Francis; Kim, Kyoung-Yeol; Chae, Kyu-Jung; Choi, Mi-Jin; Chang, In Seop; Kim, In S

    2010-03-01

    Bio-hydrogen production in light-assisted microbial electrolysis cell (MEC) with a dye sensitized solar cell (DSSC) was optimized by connecting multiple MECs to a single dye (N719) sensitized solar cell (V(OC) approx. 0.7 V). Hydrogen production occurred simultaneously in all the connected MECs when the solar cell was irradiated with light. The amount of hydrogen produced in each MEC depends on the activity of the microbial catalyst on their anode. Substrate (acetate) to hydrogen conversion efficiencies ranging from 42% to 65% were obtained from the reactors during the experiment. A moderate light intensity of 430 W m(-2) was sufficient for hydrogen production in the coupled MEC-DSSC. A higher light intensity of 915 W m(-2), as well as an increase in substrate concentration, did not show any improvement in the current density due to limitation caused by the rate of microbial oxidation on the anode. A significant reduction in the surface area of the connected DSSC only showed a slight effect on current density in the coupled MEC-DSSC system when irradiated with light.

  11. Protease Production by Different Thermophilic Fungi

    Science.gov (United States)

    Macchione, Mariana M.; Merheb, Carolina W.; Gomes, Eleni; da Silva, Roberto

    A comparative study was carried out to evaluate protease production in solid-state fermentation (SSF) and submerged fermentation (SmF) by nine different thermophilic fungi — Thermoascus aurantiacus Miehe, Thermomyces lanuginosus, T. lanuginosus TO.03, Aspergillus flavus 1.2, Aspergillus sp. 13.33, Aspergillus sp. 13.34, Aspergillus sp. 13.35, Rhizomucor pusillus 13.36 and Rhizomucor sp. 13.37 — using substrates containing proteins to induce enzyme secretion. Soybean extract (soybean milk), soybean flour, milk powder, rice, and wheat bran were tested. The most satisfactory results were obtained when using wheat bran in SSF. The fungi that stood out in SSF were T. lanuginosus, T. lanuginosus TO.03, Aspergillus sp. 13.34, Aspergillus sp. 13.35, and Rhizomucor sp. 13.37, and those in SmF were T. aurantiacus, T. lanuginosus TO.03, and 13.37. In both fermentation systems, A. flavus 1.2 and R. pusillus 13.36 presented the lowest levels of proteolytic activity.

  12. An integrated biohydrogen refinery: synergy of photofermentation, extractive fermentation and hydrothermal hydrolysis of food wastes.

    Science.gov (United States)

    Redwood, Mark D; Orozco, Rafael L; Majewski, Artur J; Macaskie, Lynne E

    2012-09-01

    An Integrated Biohydrogen Refinery (IBHR) and experimental net energy analysis are reported. The IBHR converts biomass to electricity using hydrothermal hydrolysis, extractive biohydrogen fermentation and photobiological hydrogen fermentation for electricity generation in a fuel cell. An extractive fermentation, developed previously, is applied to waste-derived substrates following hydrothermal pre-treatment, achieving 83-99% biowaste destruction. The selective separation of organic acids from waste-fed fermentations provided suitable substrate for photofermentative hydrogen production, which enhanced the gross energy generation up to 11-fold. Therefore, electrodialysis provides the key link in an IBHR for 'waste to energy'. The IBHR compares favourably to 'renewables' (photovoltaics, on-shore wind, crop-derived biofuels) and also emerging biotechnological options (microbial electrolysis) and anaerobic digestion. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. PRODUCTION AND CHARACTERIZATION OF THERMOPHILIC CARBOXYMETHYL CELLULASE SYNTHESIZED BY Bacillus sp. GROWING ON SUGARCANE BAGASSE IN SUBMERGED FERMENTATION

    Directory of Open Access Journals (Sweden)

    I. Q. M. Padilha

    2015-03-01

    Full Text Available Abstract The production and characterization of cellulase from thermophilic strain Bacillus sp. C1AC5507 was studied. For enzyme production, sugarcane bagasse was used as carbon source. The produced carboxymethyl cellulase (CMCase had a molecular weight around 55 kDa and its activity varied between 0.14 and 0.37 IU mL-1 in conditions predicted by Response Surface Methodology. The optimum temperature and pH for the CMCase production were 70 °C and 7.0, respectively. The enzyme activity was inhibited mostly by Cu+2 and activated mostly by Co+2, Mn2+, Ca+2 and Fe+3. Our findings provide a contribution to the use of natural wastes such as sugarcane bagasse as substrate for growth and production of thermophilic CMCase. Further optimization to increase the production of cellulase enables the use in industrial applications.

  14. Mesophilic and thermophilic anaerobic co-digestion of winery wastewater sludge and wine lees: An integrated approach for sustainable wine production.

    Science.gov (United States)

    Da Ros, C; Cavinato, C; Pavan, P; Bolzonella, D

    2017-12-01

    In this work, winery wastes generated by a cellar producing approximately 300,000 hL of wine per year was monitored for a period of one year. On average, 196 L of wastewater, 0.1 kg of waste activated sludge (dry matter) and 1.6 kg of wine lees were produced per hectoliter of wine produced. Different winery wastes, deriving from different production steps, namely waste activated sludge from wastewater treatment and wine lees, were co-treated using an anaerobic digestion process. Testing was conducted on a pilot scale for both mesophilic and thermophilic conditions. The process was stable for a long period at 37 °C, with an average biogas production of 0.386 m 3 /kg COD fed . On the other hand, for thermophilic conditions, volatile fatty acids accumulated in the reactor and the process failed after one hydraulic retention time (23 days). In order to fix the biological process, trace elements (iron, cobalt and nickel) were added to the feed of the thermophilic reactor. Metals augmentation improved process stability and yields at 55 °C. The pH ranged between 7.8 and 8.0, and specific gas production was 0.450 m 3 /kg COD fed , which corresponded to dry matter and COD removals of 34% and 88%, respectively. Although the observed performances in terms of biogas production were good, the thermophilic process exhibited some limitations related to both the necessity of metals addition and the worse dewaterability properties. In fact, while the mesophilic digestates reached a good dewatering quality via the addition of 6.5 g of polymer per kg of dry matter, the required dosage for the thermophilic sludge was greater than 10 g/kg of dry matter. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Production of 2-deoxyribose 5-phosphate from fructose to demonstrate a potential of artificial bio-synthetic pathway using thermophilic enzymes.

    Science.gov (United States)

    Honda, Kohsuke; Maya, Shohei; Omasa, Takeshi; Hirota, Ryuichi; Kuroda, Akio; Ohtake, Hisao

    2010-08-02

    Six thermophilic enzymes from Thermus thermophilus were used to construct an 'artificial bio-synthetic pathway' for the production of 2-deoxyribose 5-phosphate from fructose. By a simple operation using six recombinant Escherichia coli strains producing the thermophilic enzymes, respectively, fructose was converted to 2-deoxyribose 5-phosphate with a molar yield of 55%. Copyright 2010 Elsevier B.V. All rights reserved.

  16. Dual uses of microalgal biomass: An integrative approach for biohydrogen and biodiesel production

    International Nuclear Information System (INIS)

    Dasgupta, Chitralekha Nag; Suseela, M.R.; Mandotra, S.K.; Kumar, Pankaj; Pandey, Manish K.; Toppo, Kiran; Lone, J.A.

    2015-01-01

    Highlights: • Chlorella sp. NBRI029 and Scenedesmus sp. NBRI012 shows high biomass productivity. • Scenedesmus sp. NBRI012 shows maximum H 2 evolution in 6th day of fermentation. • Residual biomass after H 2 production contains high lipid content. • Lipid extracted from the residual biomass fulfills various biodiesel properties. - Abstract: Dual application of biomass for biohydrogen and biodiesel production could be considered a feasible option for economic and sustainable energy production from microalgae. In this study, after a large screening of fresh water microalgal isolates, Scenedesmus sp. NBRI012 and Chlorella sp. NBRI029 have exhibited high biomass (1.31 ± 0.11 and 2.62 ± 0.13 g/L respectively) and lipid (244.44 ± 12.3 and 587.38 ± 20.2 mg/L respectively) yield with an organic carbon (acetate) source. Scenedesmus sp. NBRI012 has shown the highest H 2 (maximum evolution of 17.72% v/v H 2 of total gases) production; it produced H 2 continuously for seven days in sulfur-deprived TAP media. Sulfur deprivation during the H 2 production was found to increase the lipid content (410.03 ± 18.5 mg/L) of the residual biomass. Fatty acid profile of the lipid extracted from the residual biomass of Scenedesmus sp. NBRI012 has showed abundance of fatty acids with a carbon chain length of C16 and C18. Cetane number, iodine value, and saponification value of biodiesel were found suitable according to the range given by the Indian standard (IS 15607), Brazilian National Petroleum Agency (ANP255) and the European biodiesel standard EN14214

  17. Effect of total solids content on biohydrogen production and lactic acid accumulation during dark fermentation of organic waste biomass.

    Science.gov (United States)

    Ghimire, Anish; Trably, Eric; Frunzo, Luigi; Pirozzi, Francesco; Lens, Piet N L; Esposito, Giovanni; Cazier, Elisabeth A; Escudié, Renaud

    2018-01-01

    Production of biohydrogen and related metabolic by-products was investigated in Solid State Dark Fermentation (SSDF) of food waste (FW) and wheat straw (WS). The effect of the total solids (TS) content and H 2 partial pressure (pp H2 ), two of the main operating factors of SSDF, were investigated. Batch tests with FW at 10, 15, 20, 25 and 30% TS showed considerable effects of the TS on metabolites distribution. H 2 production was strongly inhibited for TS contents higher than 15% with a concomitant accumulation of lactic acid and a decrease in substrate conversion. Varying the pp H2 had no significant effect on the conversion products and overall degradation of FW and WS, suggesting that pp H2 was not the main limiting factor in SSDF. This study showed that the conversion of complex substrates by SSDF depends on the substrate type and is limited by the TS content. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Cellulases from Thermophilic Fungi: Recent Insights and Biotechnological Potential

    Directory of Open Access Journals (Sweden)

    Duo-Chuan Li

    2011-01-01

    Full Text Available Thermophilic fungal cellulases are promising enzymes in protein engineering efforts aimed at optimizing industrial processes, such as biomass degradation and biofuel production. The cloning and expression in recent years of new cellulase genes from thermophilic fungi have led to a better understanding of cellulose degradation in these species. Moreover, crystal structures of thermophilic fungal cellulases are now available, providing insights into their function and stability. The present paper is focused on recent progress in cloning, expression, regulation, and structure of thermophilic fungal cellulases and the current research efforts to improve their properties for better use in biotechnological applications.

  19. Growth characteristics of the thermophilic fungus Scytalidium thermophilum in relation to production of mushroom compost.

    NARCIS (Netherlands)

    Wiegant, W.M.

    1992-01-01

    Scytalidium thermophilum is an important thermophilic fungus in the production of mushroom compost. I investigated the characteristics of this organism and present a simple model with which fungal growth in compost can be described. The model is used to predict better circumstances for rapid indoor

  20. Thermophilic microorganisms in biomining.

    Science.gov (United States)

    Donati, Edgardo Rubén; Castro, Camila; Urbieta, María Sofía

    2016-11-01

    Biomining is an applied biotechnology for mineral processing and metal extraction from ores and concentrates. This alternative technology for recovering metals involves the hydrometallurgical processes known as bioleaching and biooxidation where the metal is directly solubilized or released from the matrix for further solubilization, respectively. Several commercial applications of biomining can be found around the world to recover mainly copper and gold but also other metals; most of them are operating at temperatures below 40-50 °C using mesophilic and moderate thermophilic microorganisms. Although biomining offers an economically viable and cleaner option, its share of the world´s production of metals has not grown as much as it was expected, mainly considering that due to environmental restrictions in many countries smelting and roasting technologies are being eliminated. The slow rate of biomining processes is for sure the main reason of their poor implementation. In this scenario the use of thermophiles could be advantageous because higher operational temperature would increase the rate of the process and in addition it would eliminate the energy input for cooling the system (bioleaching reactions are exothermic causing a serious temperature increase in bioreactors and inside heaps that adversely affects most of the mesophilic microorganisms) and it would decrease the passivation of mineral surfaces. In the last few years many thermophilic bacteria and archaea have been isolated, characterized, and even used for extracting metals. This paper reviews the current status of biomining using thermophiles, describes the main characteristics of thermophilic biominers and discusses the future for this biotechnology.

  1. Analysis of energy consumption and CO{sub 2} emissions of the life cycle of bio-hydrogen applied to the Portuguese road transportation sector

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Ana Filipa; Baptista, Patricia; Silva, Carla [IDMEC (Portugal). Dept. of Mechanical Engineering

    2010-07-01

    In this work the main objective is to analyze energy consumption and CO{sub 2} emissions of biohydrogen for use in the transportation sector in Portugal. A life cycle assessment will be performed in order to evaluate bio-hydrogen pathways, having biodiesel and conventional fossil diesel as reference. The pathways were production of feedstock, pre-treatment, treatment, compression, distribution and applications. For the well-to-tank analysis the SimaPro 7.1 software and excel tools are used. This study includes not only a well-to-tank analysis but also a tank-to-wheel analysis (using ADVISOR software) estimating hydrogen consumption and electricity consumption of a fuel cell hybrid and a plug-in hybrid. Several bio-hydrogen feedstocks to produce hydrogen through fermentation processes will be considered: potato peels. (orig.)

  2. Bio-hydrogen production based on catalytic reforming of volatiles generated by cellulose pyrolysis: An integrated process for ZnO reduction and zinc nanostructures fabrication

    International Nuclear Information System (INIS)

    Maciel, Adriana Veloso; Job, Aldo Eloizo; Nova Mussel, Wagner da; Brito, Walter de; Duarte Pasa, Vanya Marcia

    2011-01-01

    The paper presents a process of cellulose thermal degradation with bio-hydrogen generation and zinc nanostructures synthesis. Production of zinc nanowires and zinc nanoflowers was performed by a novel processes based on cellulose pyrolysis, volatiles reforming and direct reduction of ZnO. The bio-hydrogen generated in situ promoted the ZnO reduction with Zn nanostructures formation by vapor-solid (VS) route. The cellulose and cellulose/ZnO samples were characterized by thermal analyses (TG/DTG/DTA) and the gases evolved were analyzed by FTIR spectroscopy (TG/FTIR). The hydrogen was detected by TPR (Temperature Programmed Reaction) tests. The results showed that in the presence of ZnO the cellulose thermal degradation produced larger amounts of H 2 when compared to pure cellulose. The process was also carried out in a tubular furnace with N 2 atmosphere, at temperatures up to 900 o C, and different heating rates. The nanostructures growth was catalyst-free, without pressure reduction, at temperatures lower than those required in the carbothermal reduction of ZnO with fossil carbon. The nanostructures were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). The optical properties were investigated by photoluminescence (PL). One mechanism was presented in an attempt to explain the synthesis of zinc nanostructures that are crystalline, were obtained without significant re-oxidation and whose morphologies are dependent on the heating rates of the process. This route presents a potential use as an industrial process taking into account the simple operational conditions, the low costs of cellulose and the importance of bio-hydrogen and nanostructured zinc.

  3. Xylanase, CM-cellulase and avicelase production by the thermophilic fungus Sporotrichum thermophile

    Energy Technology Data Exchange (ETDEWEB)

    Margaritis, A; Merchant, R; Yaguchi, M

    1983-01-01

    When wheat straw was used as C source, S. thermophile produced large amounts of xylanase extracellularly in addition to CM-cellulase and Avicelase. These enzymes were isolated by alcohol precipitation, desalting, and column chromatography. The molecular weights were estimated to be 25,0065,000 and 84,000 for xylanase, CM-cellulase, and Avicelase, respectively. Serine and threonine were the most abundant amino acids and these enzymes are very acidic proteins.

  4. High efficiency bio-hydrogen production from glucose revealed in an inoculum of heat-pretreated landfill leachate sludge

    International Nuclear Information System (INIS)

    Wong, Y.M.; Juan, J.C.; Ting, Adeline; Wu, T.Y.

    2014-01-01

    Bio-hydrogen is a promising sustainable energy to replace fossil fuels. This study investigated bio-H 2 production from the inoculum of heat-pretreated landfill leachate sludge using glucose as model substrate. The seed sludge pretreated at 65 °C showed the highest amount of H 2 at the optimum condition of pH 6 and 37 °C. The maximum H 2 yield estimated by the modified Gompertz model was 6.43 mol H 2 /mol glucose. The high efficient of H 2 production is thermodynamically feasible with the Gibbs free energy of −34 kJ/mol. This study reveals that pretreated landfill leachate sludge has considerable potential for H 2 production. - Highlights: • Heat retreated landfill leachate sludge revealed high efficient H 2 production. • High efficient H 2 yield, 6.4 mol H 2 /mol glucose. • The synergisms between H 2 -producing bacteria may responsible for the high H 2 yield. • High H 2 yield is thermodynamically feasible with Gibbs free energy of −34 kJ/mol

  5. Investigating the potential of thermophilic species for ethanol production from industrial spent sulfite liquor

    Directory of Open Access Journals (Sweden)

    Michaela Weissgram

    2015-10-01

    Full Text Available Thermophilic microorganisms hold a great potential for bioethanol production on waste biomass, due to their ability to utilize pentoses and hexoses alike. However, to date hardly any data on thermophiles growing directly on industrial substrates like spent sulfite liquor (SSL are available. This contribution investigates the ability of Thermoanaerobacter species to utilize the main sugars in the used SSL (mannose, glucose and xylose and the effect of process parameters (pH, temperature and sugar concentration on their growth. Based on these results the strain T. mathranii was chosen for further studies. The ability of T. mathranii to grow directly on SSL was investigated and the effect of several inhibiting substances on growth was elucidated. Furthermore it was tested whether pretreatment with activated charcoal can increase the fermentability of SSL. The fermentations were evaluated based on yields and specific rates. It could be shown that T. mathranii was able to ferment all sugars in the investigated softwood SSL and fermented diluted, untreated SSL (up to 2.7% (w/w dry matter. Pretreatment with activated charcoal could slightly reduce the amount of phenols in the substrate and thus facilitate growth and ethanol production on higher SSL concentrations (up to 4.7% (w/v dry matter. Ethanol yields of 0.29-0.44 Cmmol of ethanol per Cmmol sugar were obtained on untreated and pretreated spent sulfite liquor, respectively. These results on an industrial substrate strengthen the claim that thermophilic microorganisms might be the optimal candidates for forest biorefinery.

  6. Production of bioelectricity, bio-hydrogen, high value chemicals and bioinspired nanomaterials by electrochemically active biofilms.

    Science.gov (United States)

    Kalathil, Shafeer; Khan, Mohammad Mansoob; Lee, Jintae; Cho, Moo Hwan

    2013-11-01

    Microorganisms naturally form biofilms on solid surfaces for their mutual benefits including protection from environmental stresses caused by contaminants, nutritional depletion or imbalances. The biofilms are normally dangerous to human health due to their inherited robustness. On the other hand, a recent study suggested that electrochemically active biofilms (EABs) generated by electrically active microorganisms have properties that can be used to catalyze or control the electrochemical reactions in a range of fields, such as bioenergy production, bioremediation, chemical/biological synthesis, bio-corrosion mitigation and biosensor development. EABs have attracted considerable attraction in bioelectrochemical systems (BESs), such as microbial fuel cells and microbial electrolysis cells, where they act as living bioanode or biocathode catalysts. Recently, it was reported that EABs can be used to synthesize metal nanoparticles and metal nanocomposites. The EAB-mediated synthesis of metal and metal-semiconductor nanocomposites is expected to provide a new avenue for the greener synthesis of nanomaterials with high efficiency and speed than other synthetic methods. This review covers the general introduction of EABs, as well as the applications of EABs in BESs, and the production of bio-hydrogen, high value chemicals and bio-inspired nanomaterials. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Fatty acid oxidation products ('green odour') released from perennial ryegrass following biotic and abiotic stress, potentially have antimicrobial properties against the rumen microbiota resulting in decreased biohydrogenation.

    Science.gov (United States)

    Huws, S A; Scott, M B; Tweed, J K S; Lee, M R F

    2013-11-01

    In this experiment, we investigated the effect of 'green odour' products typical of those released from fresh forage postabiotic and biotic stresses on the rumen microbiota and lipid metabolism. Hydroperoxyoctadecatrienoic acid (HP), a combination of salicylic and jasmonic acid (T), and a combination of both (HPT) were incubated in vitro in the presence of freeze-dried ground silage and rumen fluid, under rumen-like conditions. 16S rRNA (16S cDNA) HaeIII-based terminal restriction fragment length polymorphism-based (T-RFLP) dendrograms, canonical analysis of principal coordinates graphs, peak number and Shanon-Weiner diversity indices show that HP, T and HPT likely had antimicrobial effects on the microbiota compared to control incubations. Following 6 h of in vitro incubation, 15.3% of 18:3n-3 and 4.4% of 18:2n-6 was biohydrogenated in control incubations, compared with 1.3, 9.4 and 8.3% of 18:3n-3 for HP, T and HPT treatments, respectively, with negligible 18:2n-6 biohydrogenation seen. T-RFLP peaks lost due to application of HP, T and HPT likely belonged to as yet uncultured bacteria within numerous genera. Hydroperoxyoctadecatrienoic acid, T and HPT released due to plant stress potentially have an antimicrobial effect on the rumen microbiota, which may explain the decreased biohydrogenation in vitro. These data suggest that these volatile chemicals may be responsible for the higher summer n-3 content of bovine milk. © 2013 The Society for Applied Microbiology.

  8. Xylose fermentation to biofuels (hydrogen and ethanol) by extreme thermophilic (70 C) mixed culture

    DEFF Research Database (Denmark)

    Chenxi, Zhao; Karakashev, Dimitar Borisov; Lu, W.

    2010-01-01

    -xylose corresponding to 55% of the theoretical hydrogen yield based on acetate metabolic pathway. An empirical model was established to reveal the quantitative effect of factors significant for biohydrogen (quadratic model) production and for bioethanol (linear model) production. Changes in hydrogen/ethanol yields...

  9. Pre-aeration of food waste to augment acidogenic process at higher organic load: Valorizing biohydrogen, volatile fatty acids and biohythane.

    Science.gov (United States)

    Sarkar, Omprakash; Venkata Mohan, S

    2017-10-01

    Application of pre-aeration (AS) to waste prior to feeding was evaluated on acidogenic process in a semi-pilot scale biosystem for the production of biobased products (biohydrogen, volatile fatty acids (VFA) and biohythane) from food waste. Oxygen assisted in pre-hydrolysis of waste along with the suppression of methanogenic activity resulting in enhanced acidogenic product formation. AS operation resulted in 97% improvement in hydrogen conversion efficiency (HCE) and 10% more VFA production than the control. Increasing the organic load (OL) of food waste in association with AS application improved the productivity. The application of AS also influenced concentration and composition of fatty acid. Highest fraction of acetic (5.3g/l), butyric (0.7g/l) and propionic acid (0.84g/l) was achieved at higher OL (100g COD/l) with good degree of acidification (DOA). AS strategy showed positive influence on biofuel (biohydrogen and biohythane) production along with the biosynthesis of short chain fatty acids functioning as a low-cost pretreatment strategy in a single stage bioprocess. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Hydrogen production from algal biomass - Advances, challenges and prospects.

    Science.gov (United States)

    Show, Kuan-Yeow; Yan, Yuegen; Ling, Ming; Ye, Guoxiang; Li, Ting; Lee, Duu-Jong

    2018-06-01

    Extensive effort is being made to explore renewable energy in replacing fossil fuels. Biohydrogen is a promising future fuel because of its clean and high energy content. A challenging issue in establishing hydrogen economy is sustainability. Biohydrogen has the potential for renewable biofuel, and could replace current hydrogen production through fossil fuel thermo-chemical processes. A promising source of biohydrogen is conversion from algal biomass, which is abundant, clean and renewable. Unlike other well-developed biofuels such as bioethanol and biodiesel, production of hydrogen from algal biomass is still in the early stage of development. There are a variety of technologies for algal hydrogen production, and some laboratory- and pilot-scale systems have demonstrated a good potential for full-scale implementation. This work presents an elucidation on development in biohydrogen encompassing biological pathways, bioreactor designs and operation and techno-economic evaluation. Challenges and prospects of biohydrogen production are also outlined. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. An experimental evaluation of energy economics of biogas production at mesophilic and thermophilic temperatures

    International Nuclear Information System (INIS)

    Ezeonu, F. C.

    1997-01-01

    Process economy, with regard to and energy content predicts the potentialities of biogas production options. Experimental study reveal from the kinetic data of daily biogas production that biomethanation reaction is faster in thermophilic digestion, with a higher yield of gas per reactor volume per day. Energy calculations show that it will take 3.55*10 5 kWh to produce 1 m 3 of methane from our feedstock with biogas energy equivalent of 1.25 kWh. The cost implication of this is enormous amounting to US $2,641.95 for the production of 1 m 3 of methane using brewers spent grins

  12. Physiology of thermophilic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Ljungdahl, L G

    1979-01-01

    Thermophilic micro-organisms have all of the properties normally found in mesophilic micro-organisms. These include metabolic pathways, regulatory mechanisms such as allosteric or feedback control, repression and induction of protein synthesis, growth yields and metabolic rates. The main difference between thermophiles and mesophiles is the former's capacity to grow at high temperatures. The basis for this capacity is the thermophile's capability to synthesize proteins, complex structures and membranes that are stable or are stabilized and functional at thermophilic temperatures. It is proposed that the maximum and minimum growth temperatures are normally determined by properties associated with proteins, and that the membrane plays a lesser role in determining these temperatures. Enzymes and other proteins from thermophiles, except for having higher thermostability, are very similar to corresponding proteins from mesophiles. The higher thermostability is generally dependent on subtle changes in the composition and sequence of the amino acids and rarely dependent on non-proteinaceous factors. Although over 100 proteins have been purified from thermophiles and compared with corresponding proteins from mesophiles, the exact nature of the higher thermostability has yet to be determined in a protein from a thermophile.

  13. Hydraulic retention time affects stable acetate production from tofu processing wastewater in extreme-thermophilic (70°C) mixed culture fermentation.

    Science.gov (United States)

    Chen, Yun; Zhang, Fang; Wang, Ting; Shen, Nan; Yu, Zhong-Wei; Zeng, Raymond J

    2016-09-01

    Acetate is an important industrial chemical and its production from wastes via mixed culture fermentation (MCF) is economic. In this work, the effect of hydraulic retention time (HRT) on acetate production from tofu processing wastewater (TPW) in extreme-thermophilic (70°C) MCF was first investigated. It was found that long HRT (>3days) could lead to less acetate production while stable acetate production was achieved at short HRT (3days) with the yield of 0.57g-COD/g-CODTPW. The microbial community analysis showed that hydrogenotrophic methanogens (mainly Methanothermobacter) occupied up to 90% of archaea at both HRTs of 3 and 5days. However, Coprothermobacter, the main acetate-degraders, decreased from 35.74% to 10.58% of bacteria when HRT decreased from 5 to 3days, supporting the aggravation of syntrophic acetate oxidation in long HRT. This work demonstrated that HRT was a crucial factor to maintain stable acetate production from TPW in extreme-thermophilic MCF. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Utilizing thermophilic microbe in lignocelluloses based bioethanol production: Review

    Science.gov (United States)

    Sriharti, Agustina, Wawan; Ratnawati, Lia; Rahman, Taufik; Salim, Takiyah

    2017-01-01

    The utilization of thermophilic microbe has attracted many parties, particularly in producing an alternative fuel like ethanol. Bioethanol is one of the alternative energy sources substituting for earth oil in the future. The advantage of using bioethanol is that it can reduce pollution levels and global warming because the result of bioethanol burning doesn't bring in a net addition of CO2 into environment. Moreover, decrease in the reserves of earth oil globally has also contributed to the notion on searching renewable energy resources such as bioethanol. Indonesia has a high biomass potential and can be used as raw material for bioethanol. The utilization of these raw materials will reduce fears of competition foodstuffs for energy production. The enzymes that play a role in degrading lignocelluloses are cellulolytic, hemicellulolytic, and lignolytic in nature. The main enzyme with an important role in bioethanol production is a complex enzyme capable of degrading lignocelluloses. The enzyme can be produced by the thermophilik microbes of the groups of bacteria and fungi such as Trichoderma viride, Clostridium thermocellum, Bacillus sp. Bioethanol production is heavily affected by raw material composition, microorganism type, and the condition of fermentation used.

  15. Production of cellulases by a thermophilic fungus, Thermoascus aurantiacus A-131

    Energy Technology Data Exchange (ETDEWEB)

    Kawamori, M; Takayama, K; Takasawa, S

    1987-01-01

    A thermophilic fungus, strain A-131, isolated from a soil sample produced cellulases in the culture fluid. The fungus (strain A-131) was identified as Thermoascus aurantiacus Miehe from its taxonomical characteristics. The cellulases of T. aurantiacus A-131 were produced constitutively without cellulase inducers. Moreover, their production was induced markedly by amorphous polysaccharides containing beta-1, 4 linkages such as alkali-treated bagasse and xylan rather than crystalline cellulose. The cultivation of T. aurantiacus A-131 at 45 degrees C with 4% alkali-treated bagasse led to the production of about 70 U/ml of CMCase after four days. The thermostability of the cellulolytic enzymes of T. aurantiacus A-131 was excellent and virtually no decreases in their activities were seen after preincubation at 60 degrees C for 24 hours. (Refs. 21).

  16. Production and storage of biohydrogen during sequential batch fermentation of Spirogyra hydrolyzate by Clostridium butyricum

    International Nuclear Information System (INIS)

    Ortigueira, Joana; Pinto, Tiago; Gouveia, Luísa; Moura, Patrícia

    2015-01-01

    The biological hydrogen production from Spirogyra sp. biomass was studied in a SBR (sequential batch reactor) equipped with a biogas collecting and storage system. Two acid hydrolysis pre-treatments (1N and 2N H 2 SO 4 ) were applied to the Spirogyra biomass and the subsequent fermentation by Clostridium butyricum DSM 10702 was compared. The 1N and 2N hydrolyzates contained 37.2 and 40.8 g/L of total sugars, respectively, and small amounts of furfural and HMF (hydroxymethylfurfural). These compounds did not inhibit the hydrogen production from crude Spirogyra hydrolyzates. The fermentation was scaled up to a batch operated bioreactor coupled with a collecting system that enabled the subsequent characterization and storage of the biogas produced. The cumulative hydrogen production was similar for both 1N and 2N hydrolyzate, but the hydrogen production rates were 438 and 288 mL/L.h, respectively, suggesting that the 1N hydrolyzate was more suitable for sequential batch fermentation. The SBR with 1N hydrolyzate was operated continuously for 13.5 h in three consecutive batches and the overall hydrogen production rate and yield reached 324 mL/L.h and 2.59 mol/mol, respectively. This corresponds to a potential daily production of 10.4 L H 2 /L Spirogyra hydrolyzate, demonstrating the excellent capability of C. butyricum to produce hydrogen from microalgal biomass. - Highlights: • Production of biohydrogen from crude Spirogyra hydrolyzates. • Set-up of a collecting and storage system for continuous biogas sampling. • The hydrogen production rate is 324 mL/L.h in the SBR (sequential batch reactor). • The SBR produces daily an equivalent to 10.4 L H 2 /L of crude Spirogyra hydrolyzate

  17. Genetic Tools and Techniques for Recombinant Expression in Thermophilic Bacillaceae

    Directory of Open Access Journals (Sweden)

    Eivind B. Drejer

    2018-05-01

    Full Text Available Although Escherichia coli and Bacillus subtilis are the most prominent bacterial hosts for recombinant protein production by far, additional species are being explored as alternatives for production of difficult-to-express proteins. In particular, for thermostable proteins, there is a need for hosts able to properly synthesize, fold, and excrete these in high yields, and thermophilic Bacillaceae represent one potentially interesting group of microorganisms for such purposes. A number of thermophilic Bacillaceae including B. methanolicus, B. coagulans, B. smithii, B. licheniformis, Geobacillus thermoglucosidasius, G. kaustophilus, and G. stearothermophilus are investigated concerning physiology, genomics, genetic tools, and technologies, altogether paving the way for their utilization as hosts for recombinant production of thermostable and other difficult-to-express proteins. Moreover, recent successful deployments of CRISPR/Cas9 in several of these species have accelerated the progress in their metabolic engineering, which should increase their attractiveness for future industrial-scale production of proteins. This review describes the biology of thermophilic Bacillaceae and in particular focuses on genetic tools and methods enabling use of these organisms as hosts for recombinant protein production.

  18. Sequential dark-photo fermentation and autotrophic microalgal growth for high-yield and CO{sub 2}-free biohydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Yung-Chung [Department of Chemical Engineering, National Cheng Kung University, Tainan 701 (China); Chen, Chun-Yen [Department of Chemical Engineering, National Cheng Kung University, Tainan 701 (China); Sustainable Environment Research Center, National Cheng Kung University, Tainan (China); Lee, Chi-Mei [Department of Environmental Engineering, National Chung Hsing University, Taichung (China); Chang, Jo-Shu [Department of Chemical Engineering, National Cheng Kung University, Tainan 701 (China); Sustainable Environment Research Center, National Cheng Kung University, Tainan (China); Center for Biosciences and Biotechnology, National Cheng Kung University, Tainan (China)

    2010-10-15

    Dark fermentation, photo fermentation, and autotrophic microalgae cultivation were integrated to establish a high-yield and CO{sub 2}-free biohydrogen production system by using different feedstock. Among the four carbon sources examined, sucrose was the most effective for the sequential dark (with Clostridium butyricum CGS5) and photo (with Rhodopseudomonas palutris WP3-5) fermentation process. The sequential dark-photo fermentation was stably operated for nearly 80 days, giving a maximum H{sub 2} yield of 11.61 mol H{sub 2}/mol sucrose and a H{sub 2} production rate of 673.93 ml/h/l. The biogas produced from the sequential dark-photo fermentation (containing ca. 40.0% CO{sub 2}) was directly fed into a microalga culture (Chlorella vulgaris C-C) cultivated at 30 C under 60 {mu}mol/m{sup 2}/s illumination. The CO{sub 2} produced from the fermentation processes was completely consumed during the autotrophic growth of C. vulgaris C-C, resulting in a microalgal biomass concentration of 1999 mg/l composed mainly of 48.0% protein, 23.0% carbohydrate and 12.3% lipid. (author)

  19. Application of polymeric membranes in biohydrogen purification and storage

    Czech Academy of Sciences Publication Activity Database

    Pientka, Zbyněk; Peter, Jakub; Žitka, Jan; Bakonyi, P.

    2014-01-01

    Roč. 1, č. 2 (2014), s. 99-105 ISSN 2212-7119 R&D Projects: GA ČR(CZ) GPP106/12/P643 Institutional support: RVO:61389013 Keywords : biohydrogen * hydrogen * membrane Subject RIV: CD - Macromolecular Chemistry

  20. Biohydrogen production from dual digestion pretreatment of poultry slaughterhouse sludge by anaerobic self-fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Sittijunda, Sureewan [Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002 (Thailand); Reungsang, Alissara [Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002 (Thailand); Fermentation Research Center for Value Added Agricultural Products, Khon Kaen University, Khon Kaen 40002 (Thailand); O-thong, Sompong [Department of Biology, Faculty of Science, Thaksin University, Patthalung 93110 (Thailand)

    2010-12-15

    Poultry slaughterhouse sludge from chicken processing wastewater treatment plant was tested for their suitability as a substrate and inoculum source for fermentation hydrogen production. Dual digestion of poultry slaughterhouse sludge was employed to produce hydrogen by batch anaerobic self-fermentation without any extra-seeds. The sludge (5% TS) was dual digested by aerobic thermophilic digestion at 55 C with the varying retention time before using as substrate in anaerobic self-fermentation. The best digestion time for enriching hydrogen-producing seeds was 48 h as it completely repressed methanogenic activity and gave the maximum hydrogen yield of 136.9 mL H{sub 2}/g TS with a hydrogen production rate of 2.56 mL H{sub 2}/L/h. The hydrogen production of treated sludge at 48 h (136.9 mL H{sub 2}/g TS) was 15 times higher than that of the raw sludge (8.83 mL H{sub 2}/g TS). With this fermentation process, tCOD value in the activated sludge could be reduced up to 30%. (author)

  1. [Effect of products of thermophilous methane fermentation on the fermentation of fruit must by Saccharomyces vini].

    Science.gov (United States)

    Mikhlin, E D; Kotomina, E N; Pisarnitsky

    1975-01-01

    Experiments were carried out to study the effect of extracts from products of thermophilous methane fermentation at a dose of 0.7+2.0 ml/100 ml on the proliferation and fermentation activity of yeast Saccharomyces vini of the Yablochnaya-7 and Vishnevaya-33 race during their cultivation in the Hansen medium and in the apple and cranberry must with a normal and elevated content of sugar and acid. In some experiments the must was enriched in (NH4)2HPO4 at a dose of 0.3 g/l. Additions of small amounts of products of thermophilous methane fermentation accelerated fermentation of fruit musts with a normal sugar content and to a greater extent musts with an increased sugar content (27%). In the must enriched in (NH4)2HPO4 an almost complete (over 98%) fermentation of sugar developed for 27 days. In the must with an increased acidity (due to citric acid added to bring titrable acidity to 25 g/l) additions of the preparation also accerlerated the begining of the fermentation and increased its intensity.

  2. Single gene insertion drives bioalcohol production by a thermophilic archaeon

    Energy Technology Data Exchange (ETDEWEB)

    Basen, M; Schut, GJ; Nguyen, DM; Lipscomb, GL; Benn, RA; Prybol, CJ; Vaccaro, BJ; Poole, FL; Kelly, RM; Adams, MWW

    2014-12-09

    Bioethanol production is achieved by only two metabolic pathways and only at moderate temperatures. Herein a fundamentally different synthetic pathway for bioalcohol production at 70 degrees C was constructed by insertion of the gene for bacterial alcohol dehydrogenase (AdhA) into the archaeon Pyrococcus furiosus. The engineered strain converted glucose to ethanol via acetate and acetaldehyde, catalyzed by the host-encoded aldehyde ferredoxin oxidoreductase (AOR) and heterologously expressed AdhA, in an energy-conserving, redox-balanced pathway. Furthermore, the AOR/AdhA pathway also converted exogenously added aliphatic and aromatic carboxylic acids to the corresponding alcohol using glucose, pyruvate, and/or hydrogen as the source of reductant. By heterologous coexpression of a membrane-bound carbon monoxide dehydrogenase, CO was used as a reductant for converting carboxylic acids to alcohols. Redirecting the fermentative metabolism of P. furiosus through strategic insertion of foreign genes creates unprecedented opportunities for thermophilic bioalcohol production. Moreover, the AOR/AdhA pathway is a potentially game-changing strategy for syngas fermentation, especially in combination with carbon chain elongation pathways.

  3. Properties of thermophilic microorganisms

    International Nuclear Information System (INIS)

    Ljungdahl, L.G.

    1984-01-01

    Microorganisms are called thermophilic or extreme thermophilic (caldo-active) if they grow and reproduce over 47 0 C and 70 0 C, respectively. A survey of growth characteristics of thermophiles is presented and it includes those which also live at extreme pH. The prevalent but not completely emcompassing theory of the ability of thermophiles to grow at high temperatures is that they have macromolecules and cell organelles with high thermostability. Work on some proteins and cell organelles from thermophiles is reviewed. The thermostabilities of these components are compared with those of the living cells, and factors which may govern optimum as well as minimum growth temperatures of microorganisms are discussed. Examples are from the literature but also include enzymes involved in tetrahydrofolate metabolism and other proteins of acetogenic therhmophilic bacteria which are presently studied in the author's laboratory

  4. Effect of food to microorganism ratio on biohydrogen production from food waste via anaerobic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Jinming [Department of Biosystems Engineering, Zhejiang University, Hangzhou 310029 (China); Department of Biological and Agricultural Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States); Zhang, Ruihong; Sun, Huawei [Department of Biological and Agricultural Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States); El-Mashad, Hamed M. [Department of Biological and Agricultural Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States); Department of Agricultural Engineering, Mansoura University, El-Mansoura (Egypt); Ying, Yibin [Department of Biosystems Engineering, Zhejiang University, Hangzhou 310029 (China)

    2008-12-15

    The effect of different food to microorganism ratios (F/M) (1-10) on the hydrogen production from the anaerobic batch fermentation of mixed food waste was studied at two temperatures, 35 {+-} 2 C and 50 {+-} 2 C. Anaerobic sludge taken from anaerobic reactors was used as inoculum. It was found that hydrogen was produced mainly during the first 44 h of fermentation. The F/M between 7 and 10 was found to be appropriate for hydrogen production via thermophilic fermentation with the highest yield of 57 ml-H{sub 2}/g VS at an F/M of 7. Under mesophilic conditions, hydrogen was produced at a lower level and in a narrower range of F/Ms, with the highest yield of 39 ml-H{sub 2}/g VS at the F/M of 6. A modified Gompertz equation adequately (R{sup 2} > 0.946) described the cumulative hydrogen production yields. This study provides a novel strategy for controlling the conditions for production of hydrogen from food waste via anaerobic fermentation. (author)

  5. Hydrogen production from carrot pulp by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana

    Energy Technology Data Exchange (ETDEWEB)

    Vrije, Truus de; Budde, Miriam A.W.; Lips, Steef J.; Bakker, Robert R.; Mars, Astrid E.; Claassen, Pieternel A.M. [Wageningen UR, Food and Biobased Research, P.O. Box 17, 6700 AA Wageningen (Netherlands)

    2010-12-15

    Hydrogen was produced from carrot pulp hydrolysate, untreated carrot pulp and (mixtures of) glucose and fructose by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana in pH-controlled bioreactors. Carrot pulp hydrolysate was obtained after enzymatic hydrolysis of the polysaccharide fraction in carrot pulp. The main sugars in the hydrolysate were glucose, fructose, and sucrose. In fermentations with glucose hydrogen yields and productivities were similar for both strains. With fructose the hydrogen yield of C. saccharolyticus was reduced which might be related to uptake of glucose and fructose by different types of transport systems. With T. neapolitana the fructose consumption rate and consequently the hydrogen productivity were low. The hydrogen yields of both thermophiles were 2.7-2.8 mol H{sub 2}/mol hexose with 10 g/L sugars from carrot pulp hydrolysate. With 20 g/L sugars the yield of T. neapolitana was 2.4 mol H{sub 2}/mol hexose while the yield of C. saccharolyticus was reduced to 1.3 mol H{sub 2}/mol hexose due to high lactate production in the stationary growth phase. C. saccharolyticus was able to grow on carrot pulp and utilized soluble sugars and, after adaptation, pectin and some (hemi)cellulose. No growth was observed with T. neapolitana when using carrot pulp in agitated fermentations. Enzymatic hydrolysis of the polysaccharide fraction prior to fermentation increased the hydrogen yield with almost 10% to 2.3 g/kg of hydrolyzed carrot pulp. (author)

  6. Potential and utilization of thermophiles and thermostable enzymes in biorefining

    Directory of Open Access Journals (Sweden)

    Karlsson Eva

    2007-03-01

    Full Text Available Abstract In today's world, there is an increasing trend towards the use of renewable, cheap and readily available biomass in the production of a wide variety of fine and bulk chemicals in different biorefineries. Biorefineries utilize the activities of microbial cells and their enzymes to convert biomass into target products. Many of these processes require enzymes which are operationally stable at high temperature thus allowing e.g. easy mixing, better substrate solubility, high mass transfer rate, and lowered risk of contamination. Thermophiles have often been proposed as sources of industrially relevant thermostable enzymes. Here we discuss existing and potential applications of thermophiles and thermostable enzymes with focus on conversion of carbohydrate containing raw materials. Their importance in biorefineries is explained using examples of lignocellulose and starch conversions to desired products. Strategies that enhance thermostablity of enzymes both in vivo and in vitro are also assessed. Moreover, this review deals with efforts made on developing vectors for expressing recombinant enzymes in thermophilic hosts.

  7. Efficient utilization of xylanase and lipase producing thermophilic ...

    African Journals Online (AJOL)

    Efficient utilization of xylanase and lipase producing thermophilic marine actinomycetes ( Streptomyces albus and Streptomyces hygroscopicus ) in the production of ecofriendly alternative energy from waste.

  8. Effects of Mesophilic and Thermophilic Temperature Condition to Biogas Production (Methane from Palm Oil Mill Effluent (POME with Cow Manures

    Directory of Open Access Journals (Sweden)

    Muhammad Fajar Fajar

    2018-01-01

    Full Text Available Biogas is an environmentally friendly renewable energy source. Biogas can be used using Palm Oil Mill Effluents (POME. However, the % yield of biogas productivity is still not optimum due to the low conversion. The biogas productivity can be optimized by adding methanogen bacteria which increase the methane production through the anaerobic fermentation process. This study aims to utilize cow manures as the source of methanogen bacteria in methane production from POME. Furthermore, this study specifically aims to obtain the optimum productivity condition of biogas production by the composition ratio of POME and cow manures to the amount of fermentation time at 35oC and 50oC for mesophilic and thermophilic bacteria, respectively. The ratio of POME and cow mature were A1 (100:0, A2 (80:20, A3 (70:30, A4 (60:40, and A5 (0:100. The highest yield of biogas production was A2 ratio using the thermophilic condition which showed 51.33% mol with the total solid decline of 73.43%, COD removal of 77.01%, and BOD removal of 70.02%.

  9. Thermophilic lignocellulose deconstruction.

    Science.gov (United States)

    Blumer-Schuette, Sara E; Brown, Steven D; Sander, Kyle B; Bayer, Edward A; Kataeva, Irina; Zurawski, Jeffrey V; Conway, Jonathan M; Adams, Michael W W; Kelly, Robert M

    2014-05-01

    Thermophilic microorganisms are attractive candidates for conversion of lignocellulose to biofuels because they produce robust, effective, carbohydrate-degrading enzymes and survive under harsh bioprocessing conditions that reflect their natural biotopes. However, no naturally occurring thermophile is known that can convert plant biomass into a liquid biofuel at rates, yields and titers that meet current bioprocessing and economic targets. Meeting those targets requires either metabolically engineering solventogenic thermophiles with additional biomass-deconstruction enzymes or engineering plant biomass degraders to produce a liquid biofuel. Thermostable enzymes from microorganisms isolated from diverse environments can serve as genetic reservoirs for both efforts. Because of the sheer number of enzymes that are required to hydrolyze plant biomass to fermentable oligosaccharides, the latter strategy appears to be the preferred route and thus has received the most attention to date. Thermophilic plant biomass degraders fall into one of two categories: cellulosomal (i.e. multienzyme complexes) and noncellulosomal (i.e. 'free' enzyme systems). Plant-biomass-deconstructing thermophilic bacteria from the genera Clostridium (cellulosomal) and Caldicellulosiruptor (noncellulosomal), which have potential as metabolic engineering platforms for producing biofuels, are compared and contrasted from a systems biology perspective. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  10. Up-Streaming Process for Glucose Oxidase by Thermophilic Penicillium sp. in Shake Flask

    OpenAIRE

    Muhammad Mohsin JAVED; Aroosh SHABIR; Sana ZAHOOR; Ikram UL-HAQ

    2012-01-01

    The present study is concerned with the production of glucose oxidase (GOD) from thermophilic Penicillium sp. in 250 mL shake flask. Fourteen different strains of thermophilic Penicillium sp. were isolated from the soil and were screened for glucose oxidase production. IIBP-13 strain gave maximum extra-cellular glucose oxidase production as compared to other isolates. Effect of submerged fermentation in shaking and static conditions, different carbon sources and incubation period on the produ...

  11. Thermophilic xylanases: from bench to bottle.

    Science.gov (United States)

    Basit, Abdul; Liu, Junquan; Rahim, Kashif; Jiang, Wei; Lou, Huiqiang

    2018-01-17

    Lignocellulosic biomass is a valuable raw material. As technology has evolved, industrial interest in new ways to take advantage of this raw material has grown. Biomass is treated with different microbial cells or enzymes under ideal industrial conditions to produce the desired products. Xylanases are the key enzymes that degrade the xylosidic linkages in the xylan backbone of the biomass, and commercial enzymes are categorized into different glycoside hydrolase families. Thermophilic microorganisms are excellent sources of industrially relevant thermostable enzymes that can withstand the harsh conditions of industrial processing. Thermostable xylanases display high-specific activity at elevated temperatures and distinguish themselves in biochemical properties, structures, and modes of action from their mesophilic counterparts. Natural xylanases can be further improved through genetic engineering. Rapid progress with genome editing, writing, and synthetic biological techniques have provided unlimited potential to produce thermophilic xylanases in their natural hosts or cell factories including bacteria, yeasts, and filamentous fungi. This review will discuss the biotechnological potential of xylanases from thermophilic microorganisms and the ways they are being optimized and produced for various industrial applications.

  12. Study on Molasses Concentration from Sugarcanne Bagasse for Biohydrogen Production using Enriched Granular Activated Carbon (GAC) Immobilised Cells by Repeated Batch Cultivation

    Science.gov (United States)

    Idris, Norfatiha; Aminah Lutpi, Nabilah; Ruhaizul Che Ridzuan, Che Mohd; Shian, Wong Yee; Nuraiti Tengku Izhar, Tengku

    2018-03-01

    Repeated batch cultivation is known as most attractive method in improving hydrogen productivity, due to the facts that this approach could minimize the reuse of the cell and the inoculum preparation. In addition, with the combination of attach growth system during the fermentation processes to produce biohydrogen, the density of cells will be increased and the cell washout could be avoided. Therefore, this study aimed to examine the effectiveness of repeated batch cultivation for enrichment of anaerobic mixed culture onto granular activated carbon (GAC) and investigate the effect of molasses concentration during immobilization of mixed culture onto the GAC. The molasses concentration using 50 %, 40 %, 30 %, 20 % and 10 % of diluted molasses were used as feedstock in the fermentation process. The maximum hydrogen production of 60 ml was obtained at 30 % of molasses concentration with 831 ppm of hydrogen concentration. Thus, the kinetic parameter obtained from the batch profiling based on modified Gompertz equation are, Hm= 58 ml for the maximum hydrogen production and Rm= 2.02 ml/h representing the hydrogen production rate.

  13. Production of bio-hydrogenated diesel by catalytic hydrotreating of palm oil over NiMoS2/γ-Al2O3 catalyst.

    Science.gov (United States)

    Srifa, Atthapon; Faungnawakij, Kajornsak; Itthibenchapong, Vorranutch; Viriya-Empikul, Nawin; Charinpanitkul, Tawatchai; Assabumrungrat, Suttichai

    2014-04-01

    Catalytic hydrotreating of palm oil (refined palm olein type) to produce bio-hydrogenated diesel (BHD) was carried out in a continuous-flow fixed-bed reactor over NiMoS2/γ-Al2O3 catalyst. Effects of dominant hydrotreating parameters: temperature: 270-420°C; H2 pressure: 15-80 bar; LHSV: 0.25-5.0 h(-1); and H2/oil ratio: 250-2000 N(cm(3)/cm(3)) on the conversion, product yield, and a contribution of hydrodeoxygenation (HDO) and decarbonylation/decarboxylation (DCO/DCO2) were investigated to find the optimal hydrotreating conditions. All calculations including product yield and the contribution of HDO and DCO/DCO2 were extremely estimated based on mole balance corresponding to the fatty acid composition in feed to fully understand deoxygenation behaviors at different conditions. These analyses demonstrated that HDO, DCO, and DCO2 reactions competitively occurred at each condition, and had different optimal and limiting conditions. The differences in the hydrotreating reactions, liquid product compositions, and gas product composition were also discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Demand-driven biogas production from sugar beet silage in a novel fixed bed disc reactor under mesophilic and thermophilic conditions.

    Science.gov (United States)

    Terboven, Christiane; Ramm, Patrice; Herrmann, Christiane

    2017-10-01

    A newly developed fixed bed disc reactor (FBDR) which combines biofilm formation on biofilm carriers and reactor agitation in one single system was assessed for its applicability to demand-driven biogas production by variable feeding of sugar beet silage. Five different feeding patterns were studied at an organic loading of 4g VS L -1 d -1 under mesophilic and thermophilic conditions. High methane yields of 449-462L N kg VS were reached. Feeding variable punctual loadings caused immediate response with 1.2- to 3.5-fold increase in biogas production rates within 15min. Although variable feeding did not induce process instability, a temporary decrease in pH-value and methane concentration below 40% occurred. Thermophilic temperature was advantageous as it resulted in a more rapid, higher methane production and less pronounced decrease in methane content after feeding. The FBDR was demonstrated to be well-suited for flexible biogas production, but further research and comparison with traditional reactor systems are required. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Biohydrogenesis in the Thermotogales

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Robert M. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Chemical and Biomolecular Engineering; Blum, Paul H. [Univ. of Nebraska, Lincoln, NE (United States). Beadle Center for Genetics; Noll, Kenneth M. [Univ. of Connecticut, Storrs, CT (United States). Dept. of Molecular and Cellular Biology

    2014-12-13

    The production and consumption of molecular hydrogen drives the physiology and bioenergetics of many microorganisms in hydrothermal environments. As such, the potential of these microorganisms as model systems to probe fundamental issues related to biohydrogen production merits consideration. It is important to understand how carbon/energy sources relate to the disposition of reducing power and, ultimately, the formation of molecular hydrogen by high temperature microorganisms. This project focused on bacteria in the thermophilic order Thermotogales, fermentative anaerobes that produce H2 from simple and complex carbohydrates.

  16. Effect of xylose and nutrients concentration on ethanol production by a newly isolated extreme thermophilic bacterium

    DEFF Research Database (Denmark)

    Tomás, Ana Faria; Karakashev, Dimitar Borisov; Angelidaki, Irini

    2011-01-01

    An extreme thermophilic ethanol-producing strain was isolated from an ethanol high-yielding mixed culture, originally isolated from a hydrogen producing reactor operated at 70 °C. Ethanol yields were assessed with increasing concentrations of xylose, up to 20 g/l. The ability of the strain to gro...... product under most of the conditions tested, including in media lacking vitamins, peptone and yeast extract. The results indicate that this new organism is a promising candidate for the development of a second generation bio-ethanol production process. © IWA Publishing 2011....

  17. Relationship between microbial community dynamics and process performance during thermophilic sludge bioleaching.

    Science.gov (United States)

    Chen, Shen-Yi; Chou, Li-Chieh

    2016-08-01

    Heavy metals can be removed from the sludge using bioleaching technologies at thermophilic condition, thereby providing an option for biotreatment of wasted sludge generated from wastewater treatment. The purposes of this study were to establish a molecular biology technique, real-time PCR, for the detection and enumeration of the sulfur-oxidizing bacteria during the thermophilic sludge bioleaching. The 16S rRNA gene for real-time PCR quantification targeted the bioleaching bacteria: Sulfobacillus thermosulfidooxidans, Sulfobacillus acidophilus, and Acidithiobacillus caldus. The specificity and stringency for thermophilic sulfur-oxidizing bacteria were tested before the experiments of monitoring the bacterial community, bacterial number during the thermophilic sludge bioleaching and the future application on testing various environmental samples. The results showed that S. acidophilus was identified as the dominant sulfur-oxidizing bacteria, while A. caldus and S. thermosulfidooxidans occurred in relatively low numbers. The total number of the sulfur-oxidizing bacteria increased during the thermophilic bioleaching process. Meanwhile, the decrease of pH, production of sulfate, degradation of SS/VSS, and solubilization of heavy metal were found to correlate well with the population of thermophilic sulfur-oxidizing bacteria during the bioleaching process. The real-time PCR used in this study is a suitable method to monitor numbers of thermophilic sulfur-oxidizing bacteria during the bioleaching process.

  18. Methanogenesis in Thermophilic Biogas Reactors

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    1995-01-01

    Methanogenesis in thermophilic biogas reactors fed with different wastes is examined. The specific methanogenic activity with acetate or hydrogen as substrate reflected the organic loading of the specific reactor examined. Increasing the loading of thermophilic reactors stabilized the process as ....... Experiments using biogas reactors fed with cow manure showed that the same biogas yield found at 550 C could be obtained at 610 C after a long adaptation period. However, propionate degradation was inhibited by increasing the temperature.......Methanogenesis in thermophilic biogas reactors fed with different wastes is examined. The specific methanogenic activity with acetate or hydrogen as substrate reflected the organic loading of the specific reactor examined. Increasing the loading of thermophilic reactors stabilized the process...... as indicated by a lower concentration of volatile fatty acids in the effluent from the reactors. The specific methanogenic activity in a thermophilic pilot-plant biogas reactor fed with a mixture of cow and pig manure reflected the stability of the reactor. The numbers of methanogens counted by the most...

  19. Biohydrogen production from xylose at extreme thermophilic temperatures (70 degrees C) by mixed culture fermentation

    DEFF Research Database (Denmark)

    Kongjan, Prawit; Min, Booki; Angelidaki, Irini

    2009-01-01

    /L. Addition of yeast extract in the cultivation medium resulted in significant improvement of hydrogen yield. The main metabolic products during xylose fermentation were acetate, ethanol, and lactate. The specific growth rates were able to fit the experimental points relatively well with Haldane equation...... solid wastes at 70 degrees C. The highest hydrogen yield of 1.62 +/- 0.02 mol-H-2/Mol-xylose(consumed) was obtained at initial xylose concentration of 0.5 g/L with synthetic medium amended with I g/L of yeast extract. Lower hydrogen yield was achieved at initial xylose concentration higher than 2 g...

  20. Glycoside hydrolase activities of thermophilic bacterial consortia adapted to switchgrass.

    Science.gov (United States)

    Gladden, John M; Allgaier, Martin; Miller, Christopher S; Hazen, Terry C; VanderGheynst, Jean S; Hugenholtz, Philip; Simmons, Blake A; Singer, Steven W

    2011-08-15

    Industrial-scale biofuel production requires robust enzymatic cocktails to produce fermentable sugars from lignocellulosic biomass. Thermophilic bacterial consortia are a potential source of cellulases and hemicellulases adapted to harsher reaction conditions than commercial fungal enzymes. Compost-derived microbial consortia were adapted to switchgrass at 60°C to develop thermophilic biomass-degrading consortia for detailed studies. Microbial community analysis using small-subunit rRNA gene amplicon pyrosequencing and short-read metagenomic sequencing demonstrated that thermophilic adaptation to switchgrass resulted in low-diversity bacterial consortia with a high abundance of bacteria related to thermophilic paenibacilli, Rhodothermus marinus, and Thermus thermophilus. At lower abundance, thermophilic Chloroflexi and an uncultivated lineage of the Gemmatimonadetes phylum were observed. Supernatants isolated from these consortia had high levels of xylanase and endoglucanase activities. Compared to commercial enzyme preparations, the endoglucanase enzymes had a higher thermotolerance and were more stable in the presence of 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]), an ionic liquid used for biomass pretreatment. The supernatants were used to saccharify [C2mim][OAc]-pretreated switchgrass at elevated temperatures (up to 80°C), demonstrating that these consortia are an excellent source of enzymes for the development of enzymatic cocktails tailored to more extreme reaction conditions.

  1. Thermophilic growth and enzymatic thermostability are polyphyletic traits within Chaetomiaceae.

    Science.gov (United States)

    van den Brink, Joost; Facun, Kryss; de Vries, Michel; Stielow, J Benjamin

    2015-12-01

    Thermophilic fungi have the potential to produce industrial-relevant thermostable enzymes, in particular for the degradation of plant biomass. Sordariales is one of the few fungal orders containing several thermophilic taxa, of which many have been associated with the production of thermostable enzymes. The evolutionary affiliation of Sordariales fungi, especially between thermophiles and non-thermophilic relatives, is however poorly understood. Phylogenetic analysis within the current study was based on sequence data, derived from a traditional Sanger and highly multiplexed targeted next generation sequencing approach of 45 isolates. The inferred phylogeny and detailed growth analysis rendered the trait 'thermophily' as polyphyletic within Chaetomiaceae (Sordariales, Sordariomycetes), and characteristic to: Myceliophthora spp., Thielavia terrestris, Chaetomium thermophilum, and Mycothermus thermophilus. Compared to mesophiles, the isolates within thermophilic taxa produced enzyme mixtures with the highest thermostability of known cellulase activities. Temperature profiles of the enzyme activities correlated strongly with the optimal growth temperatures of the isolates but not with their phylogenetic relationships. This strong correlation between growth and enzyme characteristics indicated that detailed analysis of growth does give predictive information on enzyme physiology. The variation in growth and enzyme characteristics reveals these fungi as an excellent platform to better understand fungal thermophily and enzyme thermostability. Copyright © 2015 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  2. High-rate continuous hydrogen production by Thermoanaerobacterium thermosaccharolyticum PSU-2 immobilized on heat-pretreated methanogenic granules

    Energy Technology Data Exchange (ETDEWEB)

    O-Thong, Sompong [Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet 115, DK-2800, Kgs Lyngby (Denmark); Department of Biology, Faculty of Science, Thaksin University, Patthalung 93110 (Thailand); Prasertsan, Poonsuk [Department of Industrial Biotechnology, Faculty of Agro-Industry, Prince of Songkla University, Hat-Yai, Songkhla 90120 (Thailand); Karakashev, Dimitar; Angelidaki, Irini [Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet 115, DK-2800, Kgs Lyngby (Denmark)

    2008-11-15

    Biohydrogen production from Thermoanaerobacterium thermosaccharolyticum strain PSU-2 was examined in upflow anaerobic sludge blanket (UASB) reactor and carrier-free upflow anaerobic reactor (UA), both fed with sucrose and operating at 60 C. Heat-pretreated methanogenic granules were used as carrier to immobilize T. thermosaccharolyticum strain PSU-2 in UASB reactor operated at a hydraulic retention time (HRT) ranging from 0.75 to 24 h and corresponding sucrose loading rate from 58.5 to 2.4 mmol sucrose l{sup -1} h{sup -1}. In comparison with hydrogen production rate of 12.1 mmol H{sub 2} l{sup -1} h{sup -1} obtained by carrier-free reactor upflow anaerobic (UA) system, a greatly improved hydrogen production rate up to 152 mmol H{sub 2} l{sup -1} h{sup -1} was demonstrated by the granular cells in UASB system. The biofilm of T. thermosaccharolyticum strain PSU-2 developed on treated methanogenic granules in UASB reactor substantially enhanced biomass retention (3 times), and production of hydrogen (12 times) compared to carrier-free reactor. It appears to be the most preferred process for highly efficient dark fermentative hydrogen production from sugar containing wastewater under thermophilic conditions. (author)

  3. Feasibility study on the application of rhizosphere microflora of rice for the biohydrogen production from wasted bread

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Tetsuya [Field Production Science Center, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Nishitokyo, Tokyo 188-0002 (Japan); Nishihara Environment Technology Inc., Tokyo 108-0023 (Japan); Matsumoto, Hisami [Nishihara Environment Technology Inc., Tokyo 108-0023 (Japan); Abe, Jun [AE-Bio, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113-8657 (Japan); Morita, Shigenori [Field Production Science Center, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Nishitokyo, Tokyo 188-0002 (Japan)

    2009-02-15

    We performed an experiment of continuous anaerobic hydrogen fermentation as a pilot-plant-scale test, in which waste from a bread factory was fermented by microflora of rice rhizosphere origin. The community structure of microflora during anaerobic hydrogen fermentation was analyzed using PCR-DGGE, FISH, and quinone profiles. The relation of those results to hydrogen generation was discussed. Results show that a suitable condition was a reactor temperature of 35 C, with HRT 12-36 h, volume load of 30-70 kg-COD{sub Cr}/m{sup 3} day, and maximum hydrogen production rate of 1.30 mol-H{sub 2}/mol-hexose. Regarding characteristics of microflora during fermentation, PCR-DGGE results show specific 16S rDNA band patterns; Megasphaera elsdenii and Clostridium sp. of the hydrogen-producing bacteria were identified. M. elsdenii was detected throughout the fermentation period, while Clostridium sp. of hydrogen-producing bacteria was detected on the 46th day. Furthermore, FISH revealed large amounts of Clostridium spp. in the sample. The quinone profile showed that the dominant molecular species of quinone is MK-7. Because Clostridium spp. belong to MK-7, results suggest that the quinone profile result agrees with the results of PCR-DGGE and FISH. Microflora in the rhizosphere of rice plants can be a possible resource for effective bacteria of biohydrogen production. (author)

  4. Biohydrogen recovery and purification by gas separation method

    Czech Academy of Sciences Publication Activity Database

    Búcsú, D.; Pientka, Zbyněk; Kovács, S.; Bélafi-Bakó, K.

    2006-01-01

    Roč. 200, 1-3 (2006), s. 227-229 ISSN 0011-9164. [Conference Euromembrane. Giardini Naxos - Taormina, 24.09.2006-28.09.2006] R&D Projects: GA ČR GA203/06/1207 Grant - others:Czech-Hungarian Bilateral Research Programme(HU) CZN-16/2005 Institutional research plan: CEZ:AV0Z40500505 Keywords : biohydrogen * gas separation membranes * polymer membranes Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.917, year: 2006

  5. Exploitation of algal-bacterial associations in a two-stage biohydrogen and biogas generation process.

    Science.gov (United States)

    Wirth, Roland; Lakatos, Gergely; Maróti, Gergely; Bagi, Zoltán; Minárovics, János; Nagy, Katalin; Kondorosi, Éva; Rákhely, Gábor; Kovács, Kornél L

    2015-01-01

    The growing concern regarding the use of agricultural land for the production of biomass for food/feed or energy is dictating the search for alternative biomass sources. Photosynthetic microorganisms grown on marginal or deserted land present a promising alternative to the cultivation of energy plants and thereby may dampen the 'food or fuel' dispute. Microalgae offer diverse utilization routes. A two-stage energetic utilization, using a natural mixed population of algae (Chlamydomonas sp. and Scenedesmus sp.) and mutualistic bacteria (primarily Rhizobium sp.), was tested for coupled biohydrogen and biogas production. The microalgal-bacterial biomass generated hydrogen without sulfur deprivation. Algal hydrogen production in the mixed population started earlier but lasted for a shorter period relative to the benchmark approach. The residual biomass after hydrogen production was used for biogas generation and was compared with the biogas production from maize silage. The gas evolved from the microbial biomass was enriched in methane, but the specific gas production was lower than that of maize silage. Sustainable biogas production from the microbial biomass proceeded without noticeable difficulties in continuously stirred fed-batch laboratory-size reactors for an extended period of time. Co-fermentation of the microbial biomass and maize silage improved the biogas production: The metagenomic results indicated that pronounced changes took place in the domain Bacteria, primarily due to the introduction of a considerable bacterial biomass into the system with the substrate; this effect was partially compensated in the case of co-fermentation. The bacteria living in syntrophy with the algae apparently persisted in the anaerobic reactor and predominated in the bacterial population. The Archaea community remained virtually unaffected by the changes in the substrate biomass composition. Through elimination of cost- and labor-demanding sulfur deprivation, sustainable

  6. Production and properties of two novel exopolysaccharides synthesized by a thermophilic bacterium Aeribacillus pallidus 418.

    Science.gov (United States)

    Radchenkova, Nadja; Vassilev, Spasen; Panchev, Ivan; Anzelmo, Gianluca; Tomova, Iva; Nicolaus, Barbara; Kuncheva, Margarita; Petrov, Kaloyan; Kambourova, Margarita

    2013-09-01

    Synthesis of innovative exocellular polysaccharides (EPSs) was reported for few thermophilic microorganisms as one of the mechanisms for surviving at high temperature. Thermophilic aerobic spore-forming bacteria able to produce exopolysaccharides were isolated from hydrothermal springs in Bulgaria. They were referred to four species, such as Aeribacillus pallidus, Geobacillus toebii, Brevibacillus thermoruber, and Anoxybacillus kestanbolensis. The highest production was established for the strain 418, whose phylogenetic and phenotypic properties referred it to the species A. pallidus. Maltose and NH4Cl were observed to be correspondingly the best carbon and nitrogen sources and production yield was increased more than twofold in the process of culture condition optimization. After purification of the polymer fraction, a presence of two different EPSs, electroneutral EPS 1 and negatively charged EPS 2, in a relative weight ratio 3:2.2 was established. They were heteropolysaccharides consisting of unusual high variety of sugars (six for EPS 1 and seven for EPS 2). Six of the sugars were common for both EPSs. The main sugar in EPS 1 was mannose (69.3 %); smaller quantities of glucose (11.2 %), galactosamine (6.3 %), glucosamine (5.4 %), galactose (4.7 %), and ribose (2.9 %) were also identified. The main sugar in EPS 2 was also mannose (33.9 %), followed by galactose (17.9 %), glucose (15.5 %), galactosamine (11.7 %), glucosamine (8.1 %), ribose (5.3 %), and arabinose (4.9 %). Both polymers showed high molecular weight and high thermostability.

  7. Microbial community structure in a thermophilic aerobic digester used as a sludge pretreatment process for the mesophilic anaerobic digestion and the enhancement of methane production.

    Science.gov (United States)

    Jang, Hyun Min; Park, Sang Kyu; Ha, Jeong Hyub; Park, Jong Moon

    2013-10-01

    An effective two-stage sewage sludge digestion process, consisting of thermophilic aerobic digestion (TAD) followed by mesophilic anaerobic digestion (MAD), was developed for efficient sludge reduction and methane production. Using TAD as a biological pretreatment, the total volatile suspended solid reduction (VSSR) and methane production rate (MPR) in the MAD reactor were significantly improved. According to denaturing gradient gel electrophoresis (DGGE) analysis, the results indicated that the dominant bacteria species such as Ureibacillus thermophiles and Bacterium thermus in TAD were major routes for enhancing soluble organic matter. TAD pretreatment using a relatively short SRT of 1 day showed highly increased soluble organic products and positively affected an increment of bacteria populations which performed interrelated microbial metabolisms with methanogenic species in the MAD; consequently, a quantitative real-time PCR indicated greatly increased Methanosarcinales (acetate-utilizing methanogens) in the MAD, resulting in enhanced methane production. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Performance of continuous stirred tank reactor (CSTR) on fermentative biohydrogen production from melon waste

    Science.gov (United States)

    Cahyari, K.; Sarto; Syamsiah, S.; Prasetya, A.

    2016-11-01

    This research was meant to investigate performance of continuous stirred tank reactor (CSTR) as bioreactor for producing biohydrogen from melon waste through dark fermentation method. Melon waste are commonly generated from agricultural processing stages i.e. cultivation, post-harvesting, industrial processing, and transportation. It accounted for more than 50% of total harvested fruit. Feedstock of melon waste was fed regularly to CSTR according to organic loading rate at value 1.2 - 3.6 g VS/ (l.d). Optimum condition was achieved at OLR 2.4 g VS/ (l.d) with the highest total gas volume 196 ml STP. Implication of higher OLR value is reduction of total gas volume due to accumulation of acids (pH 4.0), and lower substrate volatile solid removal. In summary, application of this method might valorize melon waste and generates renewable energy sources.

  9. Comparison of bio-hydrogen production yield capacity between asynchronous and simultaneous saccharification and fermentation processes from agricultural residue by mixed anaerobic cultures.

    Science.gov (United States)

    Li, Yameng; Zhang, Zhiping; Zhu, Shengnan; Zhang, Huan; Zhang, Yang; Zhang, Tian; Zhang, Quanguo

    2018-01-01

    Taken common agricultural residues as substrate, dark fermentation bio-hydrogen yield capacity from asynchronous saccharification and fermentation (ASF) and simultaneous saccharification and fermentation (SSF) was investigated. The highest hydrogen yield of 472.75mL was achieved with corncob using ASF. Hydrogen yield from corn straw, rice straw, corncob and sorghum stalk by SSF were 20.54%,10.31%,13.99% and 5.92% higher than ASF, respectively. The experimental data fitted well to the modified Gompertz model. SSF offered a distinct advantage over ASF with respect to reducing overall process time (60h of SSF, 108h of ASF). Meanwhile, SSF performed better than SSF with respect to shortening the lag-stage. The major metabolites of anaerobic fermentation hydrogen production by ASF and SSF were butyric acid and acetic acid. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. (Hyper)thermophilic enzymes: production and purification.

    Science.gov (United States)

    Falcicchio, Pierpaolo; Levisson, Mark; Kengen, Servé W M; Koutsopoulos, Sotirios

    2014-01-01

    The discovery of thermophilic and hyperthermophilic microorganisms, thriving at environmental temperatures near or above 100 °C, has revolutionized our ideas about the upper temperature limit at which life can exist. The characterization of (hyper)thermostable proteins has broadened our understanding and presented new opportunities for solving one of the most challenging problems in biophysics: how is structural stability and biological function maintained at high temperatures where "normal" proteins undergo dramatic structural changes? In our laboratory we have purified and studied many thermostable and hyperthermostable proteins in an attempt to determine the molecular basis of heat stability. Here, we present methods to express such proteins and enzymes in E. coli and provide a general protocol for overproduction and purification. The ability to produce enzymes that retain their stability and activity at elevated temperatures creates exciting opportunities for a wide range of biocatalytic applications.

  11. Temperature and duration of heating of sunflower oil affect ruminal biohydrogenation of linoleic acid in vitro

    OpenAIRE

    Privé , Florence; Combes, Sylvie; Cauquil, Laurent; Farizon, Yves; Enjalbert, Francis; Troegeler-Meynadier, Annabelle

    2010-01-01

    Sunflower oil heated at 110 or 150°C for 1, 3, or 6 h was incubated with ruminal content in order to investigate the effects of temperature and duration of heating of oil on the ruminal biohydrogenation of linoleic acid in vitro. When increased, these 2 parameters acted together to decrease the disappearance of linoleic acid in the media by inhibiting the isomerization of linoleic acid, which led to a decrease in conjugated linoleic acids and trans-C18:1 production. Nevertheless, trans-10 iso...

  12. Comparative genomic analysis of the thermophilic biomass-degrading fungi Myceliophthora thermophila and Thielavia terrestris

    Energy Technology Data Exchange (ETDEWEB)

    Berka, Randy M.; Grigoriev, Igor V.; Otillar, Robert; Salamov, Asaf; Grimwood, Jane; Reid, Ian; Ishmael, Nadeeza; John, Tricia; Darmond, Corinne; Moisan, Marie-Claude; Henrissat, Bernard; Coutinho, Pedro M.; Lombard, Vincent; Natvig, Donald O.; Lindquist, Erika; Schmutz, Jeremy; Lucas, Susan; Harris, Paul; Powlowski, Justin; Bellemare, Annie; Taylor, David; Butler, Gregory; de Vries, Ronald P.; Allijn, Iris E.; van den Brink, Joost; Ushinsky, Sophia; Storms, Reginald; Powell, Amy J.; Paulsen, Ian T.; Elbourne, Liam D. H.; Baker, Scott. E.; Magnuson, Jon; LaBoissiere, Sylvie; Clutterbuck, A. John; Martinez, Diego; Wogulis, Mark; Lopez de Leon, Alfredo; Rey, Michael W.; Tsang, Adrian

    2011-05-16

    Thermostable enzymes and thermophilic cell factories may afford economic advantages in the production of many chemicals and biomass-based fuels. Here we describe and compare the genomes of two thermophilic fungi, Myceliophthora thermophila and Thielavia terrestris. To our knowledge, these genomes are the first described for thermophilic eukaryotes and the first complete telomere-to-telomere genomes for filamentous fungi. Genome analyses and experimental data suggest that both thermophiles are capable of hydrolyzing all major polysaccharides found in biomass. Examination of transcriptome data and secreted proteins suggests that the two fungi use shared approaches in the hydrolysis of cellulose and xylan but distinct mechanisms in pectin degradation. Characterization of the biomass-hydrolyzing activity of recombinant enzymes suggests that these organisms are highly efficient in biomass decomposition at both moderate and high temperatures. Furthermore, we present evidence suggesting that aside from representing a potential reservoir of thermostable enzymes, thermophilic fungi are amenable to manipulation using classical and molecular genetics.

  13. ENDOSPORES OF THERMOPHILIC FERMENTATIVE BACTERIA

    DEFF Research Database (Denmark)

    Volpi, Marta

    2016-01-01

    solely based on endospores of sulphate-reducing bacteria (SRB), which presumably constitute only a small fraction of the total thermophilic endospore community reaching cold environments. My PhD project developed an experimental framework for using thermophilic fermentative endospores (TFEs) to trace...

  14. Production and characterization of an acido-thermophilic, organic solvent stable cellulase from Bacillus sonorensis HSC7 by conversion of lignocellulosic wastes

    Directory of Open Access Journals (Sweden)

    Fatemeh Azadian

    2017-06-01

    Full Text Available The acidophilic and thermophilic cellulase would facilitate the conversion of lignocellulosic biomass to biofuel. In this study, Bacillus sonorensis HSC7 isolated as the best thermophilic cellulose degrading bacterium from Gorooh hot spring. 16S rRNA gene sequencing showed that, this strain closely related to the B. sonorensis. CMCase production was considered under varying environmental parameters. Results showed that, sucrose and (NH42SO4 were obtained as the best carbon and nitrogen sources for CMCase production. B. sonorensis HSC7 produced CMCase during the growth in optimized medium supplemented with agricultural wastes as sole carbon sources. The enzyme was active with optimum temperature of 70 °C and the optimum CMCase activity and stability observed at pH 4.0 and 5.0, respectively. These are characteristics indicating that, this enzyme could be an acidophilic and thermophilic CMCase. Furthermore, the CMCase activity improved by methanol (166%, chloroform (152%, while it was inhibited by DMF (61%. The CMCase activity was enhanced in the presence of Mg+2 (110%, Cu+2 (116%, Triton X-100 (118% and it retained 57% of its activity at 30% NaCl. The compatibility of HSC7 CMCase varied for each laundry detergent, with higher stability being observed in the presence of Taj® and darya®. This enzyme, that is able to work under extreme conditions, has potential applications in various industries.

  15. Production of Bio-Hydrogenated Diesel by Hydrotreatment of High-Acid-Value Waste Cooking Oil over Ruthenium Catalyst Supported on Al-Polyoxocation-Pillared Montmorillonite

    Directory of Open Access Journals (Sweden)

    Kinya Sakanishi

    2012-02-01

    Full Text Available Waste cooking oil with a high-acid-value (28.7 mg-KOH/g-oil was converted to bio-hydrogenated diesel by a hydrotreatment process over supported Ru catalysts. The standard reaction temperature, H2 pressure, liquid hourly space velocity (LHSV, and H2/oil ratio were 350 °C, 2 MPa, 15.2 h–1, and 400 mL/mL, respectively. Both the free fatty acids and the triglycerides in the waste cooking oil were deoxygenated at the same time to form hydrocarbons in the hydrotreatment process. The predominant liquid hydrocarbon products (98.9 wt% were n-C18H38, n-C17H36, n-C16H34, and n-C15H32 when a Ru/SiO2 catalyst was used. These long chain normal hydrocarbons had high melting points and gave the liquid hydrocarbon product over Ru/SiO2 a high pour point of 20 °C. Ru/H-Y was not suitable for producing diesel from waste cooking oil because it formed a large amount of C5–C10 gasoline-ranged paraffins on the strong acid sites of HY. When Al-polyoxocation-pillared montmorillonite (Al13-Mont was used as a support for the Ru catalyst, the pour point of the liquid hydrocarbon product decreased to −15 °C with the conversion of a significant amount of C15–C18 n-paraffins to iso-paraffins and light paraffins on the weak acid sites of Al13-Mont. The liquid product over Ru/Al13-Mont can be expected to give a green diesel for current diesel engines because its chemical composition and physical properties are similar to those of commercial petro-diesel. A relatively large amount of H2 was consumed in the hydrogenation of unsaturated C=C bonds and the deoxygenation of C=O bonds in the hydrotreatment process. A sulfided Ni-Mo/Al13-Mont catalyst also produced bio-hydrogenated diesel by the hydrotreatment process but it showed slow deactivation during the reaction due to loss of sulfur. In contrast, Ru/Al13-Mont did not show catalyst deactivation in the hydrotreatment of waste cooking oil after 72 h on-stream because the waste cooking oil was not found to contain sulfur

  16. High performance biological methanation in a thermophilic anaerobic trickle bed reactor.

    Science.gov (United States)

    Strübing, Dietmar; Huber, Bettina; Lebuhn, Michael; Drewes, Jörg E; Koch, Konrad

    2017-12-01

    In order to enhance energy efficiency of biological methanation of CO 2 and H 2 , this study investigated the performance of a thermophilic (55°C) anaerobic trickle bed reactor (ATBR) (58.1L) at ambient pressure. With a methane production rate of up to 15.4m 3 CH4 /(m 3 trickle bed ·d) at methane concentrations above 98%, the ATBR can easily compete with the performance of other mixed culture methanation reactors. Control of pH and nutrient supply turned out to be crucial for stable operation and was affected significantly by dilution due to metabolic water production, especially during demand-orientated operation. Considering practical applications, inoculation with digested sludge, containing a diverse biocenosis, showed high adaptive capacity due to intrinsic biological diversity. However, no macroscopic biofilm formation was observed at thermophilic conditions even after 313days of operation. The applied approach illustrates the high potential of thermophilic ATBRs as a very efficient energy conversion and storage technology. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Novel thermophilic hemicellulases for the conversion of lignocellulose for second generation biorefineries.

    Science.gov (United States)

    Cobucci-Ponzano, Beatrice; Strazzulli, Andrea; Iacono, Roberta; Masturzo, Giuseppe; Giglio, Rosa; Rossi, Mosè; Moracci, Marco

    2015-10-01

    The biotransformation of lignocellulose biomasses into fermentable sugars is a very complex procedure including, as one of the most critical steps, the (hemi) cellulose hydrolysis by specific enzymatic cocktails. We explored here, the potential of stable glycoside hydrolases from thermophilic organisms, so far not used in commercial enzymatic preparations, for the conversion of glucuronoxylan, the major hemicellulose of several energy crops. Searches in the genomes of thermophilic bacteria led to the identification, efficient production, and detailed characterization of novel xylanase and α-glucuronidase from Alicyclobacillus acidocaldarius (GH10-XA and GH67-GA, respectively) and a α-glucuronidase from Caldicellulosiruptor saccharolyticus (GH67-GC). Remarkably, GH10-XA, if compared to other thermophilic xylanases from this family, coupled good specificity on beechwood xylan and the best stability at 65 °C (3.5 days). In addition, GH67-GC was the most stable α-glucuronidases from this family and the first able to hydrolyse both aldouronic acid and aryl-α-glucuronic acid substrates. These enzymes, led to the very efficient hydrolysis of beechwood xylan by using 7- to 9-fold less protein (concentrations thermophilic enzymes. In addition, remarkably, together with a thermophilic β-xylosidase, they catalyzed the production of xylose from the smart cooking pre-treated biomass of one of the most promising energy crops for second generation biorefineries. We demonstrated that search by the CAZy Data Bank of currently available genomes and detailed enzymatic characterization of recombinant enzymes allow the identification of glycoside hydrolases with novel and interesting properties and applications. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Mesophilic and thermophilic biotreatment of BTEX-polluted air in reactors.

    Science.gov (United States)

    Mohammad, Balsam T; Veiga, María C; Kennes, Christian

    2007-08-15

    This study compares the removal of a mixture of benzene, toluene, ethylbenzene, and all three xylene isomers (BTEX) in mesophilic and thermophilic (50 degrees C) bioreactors. In the mesophilic reactor fungi became dominant after long-term operation, while bacteria dominated in the thermophilic unit. Microbial acclimation was achieved by exposing the biofilters to initial BTEX loads of 2-15 g m(-3) h(-1), at an empty bed residence time of 96 s. After adaptation, the elimination capacities ranged from 3 to 188 g m(-3) h(-1), depending on the inlet load, for the mesophilic biofilter with removal efficiencies reaching 96%. On the other hand, in the thermophilic reactor the average removal efficiency was 83% with a maximum elimination capacity of 218 g m(-3) h(-1). There was a clear positive relationship between temperature gradients as well as CO(2) production and elimination capacities across the biofilters. The gas phase was sampled at different depths along the reactors observing that the percentage pollutant removal in each section was strongly dependant on the load applied. The fate of individual alkylbenzene compounds was checked, showing the unusually high biodegradation rate of benzene at high loads under thermophilic conditions (100%) compared to its very low removal in the mesophilic reactor at such load (<10%). Such difference was less pronounced for the other pollutants. After 210 days of operation, the dry biomass content for the mesophilic and thermophilic reactors were 0.300 and 0.114 g g(-1) (support), respectively, reaching higher removals under thermophilic conditions with a lower biomass accumulation, that is, lower pressure drop. (c) 2007 Wiley Periodicals, Inc.

  19. Thermophilic Fungi: Their Physiology and Enzymes†

    Science.gov (United States)

    Maheshwari, Ramesh; Bharadwaj, Girish; Bhat, Mahalingeshwara K.

    2000-01-01

    Thermophilic fungi are a small assemblage in mycota that have a minimum temperature of growth at or above 20°C and a maximum temperature of growth extending up to 60 to 62°C. As the only representatives of eukaryotic organisms that can grow at temperatures above 45°C, the thermophilic fungi are valuable experimental systems for investigations of mechanisms that allow growth at moderately high temperature yet limit their growth beyond 60 to 62°C. Although widespread in terrestrial habitats, they have remained underexplored compared to thermophilic species of eubacteria and archaea. However, thermophilic fungi are potential sources of enzymes with scientific and commercial interests. This review, for the first time, compiles information on the physiology and enzymes of thermophilic fungi. Thermophilic fungi can be grown in minimal media with metabolic rates and growth yields comparable to those of mesophilic fungi. Studies of their growth kinetics, respiration, mixed-substrate utilization, nutrient uptake, and protein breakdown rate have provided some basic information not only on thermophilic fungi but also on filamentous fungi in general. Some species have the ability to grow at ambient temperatures if cultures are initiated with germinated spores or mycelial inoculum or if a nutritionally rich medium is used. Thermophilic fungi have a powerful ability to degrade polysaccharide constituents of biomass. The properties of their enzymes show differences not only among species but also among strains of the same species. Their extracellular enzymes display temperature optima for activity that are close to or above the optimum temperature for the growth of organism and, in general, are more heat stable than those of the mesophilic fungi. Some extracellular enzymes from thermophilic fungi are being produced commercially, and a few others have commercial prospects. Genes of thermophilic fungi encoding lipase, protease, xylanase, and cellulase have been cloned and

  20. Myceliophthora thermophila syn. Sporotrichum thermophile: a thermophilic mould of biotechnological potential.

    Science.gov (United States)

    Singh, Bijender

    2016-01-01

    Myceliophthora thermophila syn. Sporotrichum thermophile is a ubiquitous thermophilic mould with a strong ability to degrade organic matter during optimal growth at 45 °C. Both genome analysis and experimental data have suggested that the mould is capable of hydrolyzing all major polysaccharides found in biomass. The mould is able to secrete a large number of hydrolytic enzymes (cellulases, laccases, xylanases, pectinases, lipases, phytases and some other miscellaneous enzymes) employed in various biotechnological applications. Characterization of the biomass-hydrolyzing activity of wild and recombinant enzymes suggests that this mould is highly efficient in biomass decomposition at both moderate and high temperatures. The native enzymes produced by the mould are more efficient in activity than their mesophilic counterparts beside their low enzyme titers. The mould is able to synthesize various biomolecules, which are used in multifarious applications. Genome sequence data of M. thermophila also supported the physiological data. This review describes the biotechnological potential of thermophilic mould, M. thermophila supported by genomic and experimental evidences.

  1. Alcohol dehydrogenases from thermophilic and hyperthermophilic archaea and bacteria.

    Science.gov (United States)

    Radianingtyas, Helia; Wright, Phillip C

    2003-12-01

    Many studies have been undertaken to characterise alcohol dehydrogenases (ADHs) from thermophiles and hyperthermophiles, mainly to better understand their activities and thermostability. To date, there are 20 thermophilic archaeal and 17 thermophilic bacterial strains known to have ADHs or similar enzymes, including the hypothetical proteins. Some of these thermophiles are found to have multiple ADHs, sometimes of different types. A rigid delineation of amino acid sequences amongst currently elucidated thermophilic ADHs and similar proteins is phylogenetically apparent. All are NAD(P)-dependent, with one exception that utilises the cofactor F(420) instead. Within the NAD(P)-dependent group, the thermophilic ADHs are orderly clustered as zinc-dependent ADHs, short-chain ADHs, and iron-containing/activated ADHs. Distance matrix calculations reveal that thermophilic ADHs within one type are homologous, with those derived from a single genus often showing high similarities. Elucidation of the enzyme activity and stability, coupled with structure analysis, provides excellent information to explain the relationship between them, and thermophilic ADHs diversity.

  2. Utilization of deoiled Jatropha curcas seed cake for production of xylanase from thermophilic Scytalidium thermophilum.

    Science.gov (United States)

    Joshi, Chetna; Khare, S K

    2011-01-01

    Jatropha curcas is a major biodiesel crop. Large amount of deoiled cake is generated as by-product during biodiesel production from its seeds. Deoiled J. curcas seed cake was assessed as substrate for the production of xylanase from thermophilic fungus Scytalidium thermophilum by solid-state fermentation. The seed cake was efficiently utilized by S. thermophilum for its growth during which it produced good amount of heat stable extracellular xylanase. The solid-state fermentation conditions were optimized for maximum xylanase production. Under the optimized conditions viz. deoiled seed cake supplemented with 1% oat-spelt xylan, adjusted to pH 9.0, moisture content 1:3 w/v, inoculated with 1×10(6) spores per 5 g cake and incubated at 45 °C, 1455 U xylanase/g deoiled seed cake was obtained. The xylanase was useful in biobleaching of paper pulp. Solid-state fermentation of deoiled cake appears a potentially viable approach for its effective utilization. Copyright © 2010 Elsevier Ltd. All rights reserved.

  3. Anaerobic Thermophiles

    Directory of Open Access Journals (Sweden)

    Francesco Canganella

    2014-02-01

    Full Text Available The term “extremophile” was introduced to describe any organism capable of living and growing under extreme conditions. With the further development of studies on microbial ecology and taxonomy, a variety of “extreme” environments have been found and an increasing number of extremophiles are being described. Extremophiles have also been investigated as far as regarding the search for life on other planets and even evaluating the hypothesis that life on Earth originally came from space. The first extreme environments to be largely investigated were those characterized by elevated temperatures. The naturally “hot environments” on Earth range from solar heated surface soils and water with temperatures up to 65 °C, subterranean sites such as oil reserves and terrestrial geothermal with temperatures ranging from slightly above ambient to above 100 °C, to submarine hydrothermal systems with temperatures exceeding 300 °C. There are also human-made environments with elevated temperatures such as compost piles, slag heaps, industrial processes and water heaters. Thermophilic anaerobic microorganisms have been known for a long time, but scientists have often resisted the belief that some organisms do not only survive at high temperatures, but actually thrive under those hot conditions. They are perhaps one of the most interesting varieties of extremophilic organisms. These microorganisms can thrive at temperatures over 50 °C and, based on their optimal temperature, anaerobic thermophiles can be subdivided into three main groups: thermophiles with an optimal temperature between 50 °C and 64 °C and a maximum at 70 °C, extreme thermophiles with an optimal temperature between 65 °C and 80 °C, and finally hyperthermophiles with an optimal temperature above 80 °C and a maximum above 90 °C. The finding of novel extremely thermophilic and hyperthermophilic anaerobic bacteria in recent years, and the fact that a large fraction of them belong

  4. Deletion of the hfsB gene increases ethanol production in Thermoanaerobacterium saccharolyticum and several other thermophilic anaerobic bacteria.

    Science.gov (United States)

    Eminoğlu, Ayşenur; Murphy, Sean Jean-Loup; Maloney, Marybeth; Lanahan, Anthony; Giannone, Richard J; Hettich, Robert L; Tripathi, Shital A; Beldüz, Ali Osman; Lynd, Lee R; Olson, Daniel G

    2017-01-01

    With the discovery of interspecies hydrogen transfer in the late 1960s (Bryant et al. in Arch Microbiol 59:20-31, 1967), it was shown that reducing the partial pressure of hydrogen could cause mixed acid fermenting organisms to produce acetate at the expense of ethanol. Hydrogen and ethanol are both more reduced than glucose. Thus there is a tradeoff between production of these compounds imposed by electron balancing requirements; however, the mechanism is not fully known. Deletion of the hfsA or B subunits resulted in a roughly 1.8-fold increase in ethanol yield. The increase in ethanol production appears to be associated with an increase in alcohol dehydrogenase activity, which appears to be due, at least in part, to increased expression of the adhE gene, and may suggest a regulatory linkage between hfsB and adhE . We studied this system most intensively in the organism Thermoanaerobacterium saccharolyticum ; however, deletion of hfsB also increases ethanol production in other thermophilic bacteria suggesting that this could be used as a general technique for engineering thermophilic bacteria for improved ethanol production in organisms with hfs -type hydrogenases. Since its discovery by Shaw et al. (JAMA 191:6457-64, 2009), the hfs hydrogenase has been suspected to act as a regulator due to the presence of a PAS domain. We provide additional support for the presence of a regulatory phenomenon. In addition, we find a practical application for this scientific insight, namely increasing ethanol yield in strains that are of interest for ethanol production from cellulose or hemicellulose. In two of these organisms ( T. xylanolyticum and T. thermosaccharolyticum ), the ethanol yields are the highest reported to date.

  5. A critical review on factors influencing fermentative hydrogen production.

    Science.gov (United States)

    Kothari, Richa; Kumar, Virendra; Pathak, Vinayak V; Ahmad, Shamshad; Aoyi, Ochieng; Tyagi, V V

    2017-03-01

    Biohydrogen production by dark fermentation of different waste materials is a promising approach to produce bio-energy in terms of renewable energy exploration. This communication has reviewed various influencing factors of dark fermentation process with detailed account of determinants in biohydrogen production. It has also focused on different factors such as improved bacterial strain, reactor design, metabolic engineering and two stage processes to enhance the bioenergy productivity from substrate. The study also suggest that complete utilization of substrates for biological hydrogen production requires the concentrated research and development for efficient functioning of microorganism with integrated application for energy production and bioremediation. Various studies have been taken into account here, to show the comparative efficiency of different substrates and operating conditions with inhibitory factors and pretreatment option for biohydrogen production. The study reveals that an extensive research is needed to observe field efficiency of process using low cost substrates and integration of dark and photo fermentation process. Integrated approach of fermentation process will surely compete with conventional hydrogen process and replace it completely in future.

  6. Mesophilic and thermophilic anaerobic biodegradability of water hyacinth pre-treated at 80 degrees C.

    Science.gov (United States)

    Ferrer, Ivet; Palatsi, Jordi; Campos, Elena; Flotats, Xavier

    2010-10-01

    Water hyacinth (Eichornia crassipes) is a fast growing aquatic plant which causes environmental problems in continental water bodies. Harvesting and handling this plant becomes an issue, and focus has been put on the research of treatment alternatives. Amongst others, energy production through biomethanation has been proposed. The aim of this study was to assess the anaerobic biodegradability of water hyacinth under mesophilic and thermophilic conditions. The effect of a thermal sludge pre-treatment at 80 degrees C was also evaluated. To this end, anaerobic biodegradability tests were carried out at 35 degrees C and 55 degrees C, with raw and pre-treated water hyacinth. According to the results, the thermal pre-treatment enhanced the solubilisation of water hyacinth (i.e. increase in the soluble to total chemical oxygen demand (COD)) from 4% to 12% after 30 min. However, no significant effect was observed on the methane yields (150-190 L CH(4)/kg volatile solids). Initial methane production rates for thermophilic treatments were two fold those of mesophilic ones (6-6.5L vs. 3-3.5 L CH(4)/kg COD x day). Thus, higher methane production rates might be expected from thermophilic reactors working at short retention times. The study of longer low temperature pre-treatments or pre-treatments at elevated temperatures coupled to thermophilic reactors should be considered in the future. (c) 2009 Elsevier Ltd. All rights reserved.

  7. Mesophilic and thermophilic anaerobic biodegradability of water hyacinth pre-treated at 80 oC

    International Nuclear Information System (INIS)

    Ferrer, Ivet; Palatsi, Jordi; Campos, Elena; Flotats, Xavier

    2010-01-01

    Water hyacinth (Eichornia crassipes) is a fast growing aquatic plant which causes environmental problems in continental water bodies. Harvesting and handling this plant becomes an issue, and focus has been put on the research of treatment alternatives. Amongst others, energy production through biomethanation has been proposed. The aim of this study was to assess the anaerobic biodegradability of water hyacinth under mesophilic and thermophilic conditions. The effect of a thermal sludge pre-treatment at 80 o C was also evaluated. To this end, anaerobic biodegradability tests were carried out at 35 o C and 55 o C, with raw and pre-treated water hyacinth. According to the results, the thermal pre-treatment enhanced the solubilisation of water hyacinth (i.e. increase in the soluble to total chemical oxygen demand (COD)) from 4% to 12% after 30 min. However, no significant effect was observed on the methane yields (150-190 L CH 4 /kg volatile solids). Initial methane production rates for thermophilic treatments were two fold those of mesophilic ones (6-6.5 L vs. 3-3.5 L CH 4 /kg COD.day). Thus, higher methane production rates might be expected from thermophilic reactors working at short retention times. The study of longer low temperature pre-treatments or pre-treatments at elevated temperatures coupled to thermophilic reactors should be considered in the future.

  8. Status on Science and Application of Thermophilic Anaerobic Digestion

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    1994-01-01

    Thermophilic anaerobic processes are often regarded as less stable than mesophilic processes. In the paper this postulate is examined and disproved based on real operational data from of full-scale mesophilic and thermophilic biogas plants. The start-up produce for the thermophilic plants was...... for thermophilic digestion along with the implications for the methanogenic bacteria active at these temperatures....

  9. Thermophilic archaeal enzymes and applications in biocatalysis.

    Science.gov (United States)

    Littlechild, Jennifer A

    2011-01-01

    Thermophilic enzymes have advantages for their use in commercial applications and particularly for the production of chiral compounds to produce optically pure pharmaceuticals. They can be used as biocatalysts in the application of 'green chemistry'. The thermophilic archaea contain enzymes that have already been used in commercial applications such as the L-aminoacylase from Thermococcus litoralis for the resolution of amino acids and amino acid analogues. This enzyme differs from bacterial L-aminoacylases and has similarities to carboxypeptidases from other archaeal species. An amidase/γ-lactamase from Sulfolobus solfataricus has been used for the production of optically pure γ-lactam, the building block for antiviral carbocyclic nucleotides. This enzyme has similarities to the bacterial signature amidase family. An alcohol dehydrogenase from Aeropyrum pernix has been used for the production of optically pure alcohols and is related to the zinc-containing eukaryotic alcohol dehydrogenases. A transaminase and a dehalogenase from Sulfolobus species have also been studied. The archaeal transaminase is found in a pathway for serine synthesis which is found only in eukaryotes and not in bacteria. It can be used for the asymmetric synthesis of homochiral amines of high enantioselective purity. The L-2-haloacid dehalogenase has applications both in biocatalysis and in bioremediation. All of these enzymes have increased thermostability over their mesophilic counterparts.

  10. Production and Characterization of an Extracellular Acid Protease from Thermophilic Brevibacillus sp. OA30 Isolated from an Algerian Hot Spring.

    Science.gov (United States)

    Gomri, Mohamed Amine; Rico-Díaz, Agustín; Escuder-Rodríguez, Juan-José; El Moulouk Khaldi, Tedj; González-Siso, María-Isabel; Kharroub, Karima

    2018-04-12

    Proteases have numerous biotechnological applications and the bioprospection for newly-thermostable proteases from the great biodiversity of thermophilic microorganisms inhabiting hot environments, such as geothermal sources, aims to discover more effective enzymes for processes at higher temperatures. We report in this paper the production and the characterization of a purified acid protease from strain OA30, a moderate thermophilic bacterium isolated from an Algerian hot spring. Phenotypic and genotypic study of strain OA30 was followed by the production of the extracellular protease in a physiologically-optimized medium. Strain OA30 showed multiple extracellular proteolytic enzymes and protease 32-F38 was purified by chromatographic methods and its biochemical characteristics were studied. Strain OA30 was affiliated with Brevibacillus thermoruber species. Protease 32-F38 had an estimated molecular weight of 64.6 kDa and was optimally active at 50 °C. It showed a great thermostability after 240 min and its optimum pH was 6.0. Protease 32-F38 was highly stable in the presence of different detergents and solvents and was inhibited by metalloprotease inhibitors. The results of this work suggest that protease 32-F38 might have interesting biotechnological applications.

  11. Production and Characterization of an Extracellular Acid Protease from Thermophilic Brevibacillus sp. OA30 Isolated from an Algerian Hot Spring

    Directory of Open Access Journals (Sweden)

    Mohamed Amine Gomri

    2018-04-01

    Full Text Available Proteases have numerous biotechnological applications and the bioprospection for newly-thermostable proteases from the great biodiversity of thermophilic microorganisms inhabiting hot environments, such as geothermal sources, aims to discover more effective enzymes for processes at higher temperatures. We report in this paper the production and the characterization of a purified acid protease from strain OA30, a moderate thermophilic bacterium isolated from an Algerian hot spring. Phenotypic and genotypic study of strain OA30 was followed by the production of the extracellular protease in a physiologically-optimized medium. Strain OA30 showed multiple extracellular proteolytic enzymes and protease 32-F38 was purified by chromatographic methods and its biochemical characteristics were studied. Strain OA30 was affiliated with Brevibacillus thermoruber species. Protease 32-F38 had an estimated molecular weight of 64.6 kDa and was optimally active at 50 °C. It showed a great thermostability after 240 min and its optimum pH was 6.0. Protease 32-F38 was highly stable in the presence of different detergents and solvents and was inhibited by metalloprotease inhibitors. The results of this work suggest that protease 32-F38 might have interesting biotechnological applications.

  12. Hydrogen production by Escherichia coli {delta}hycA {delta}lacI using cheese whey as substrate

    Energy Technology Data Exchange (ETDEWEB)

    Rosales-Colunga, Luis Manuel; Ordonez, Leandro G.; De Leon-Rodriguez, Antonio (Division de Biologia Molecular, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Col. Lomas 4a secc. CP 78216, San Luis Potosi, SLP. Mexico); Razo-Flores, Elias; Alatriste-Mondragon, Felipe (Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Col. Lomas 4a secc. CP 78216, San Luis Potosi, SLP. Mexico)

    2010-01-15

    This study reports a fermentative hydrogen production by Escherichia coli using cheese whey as substrate. To improve the biohydrogen production, an E. coli {delta}hycA {delta}lacI strain (WDHL) was constructed. The absence of hycA and lacI genes had a positive effect on the biohydrogen production. The strain produced 22% more biohydrogen in a shorter time than the wild-type (WT) strain. A Box-Behnken experimental design was used to optimize pH, temperature and substrate concentration. The optimal initial conditions for biohydrogen production by WDHL strain were pH 7.5, 37 C and 20 g/L of cheese whey. The specific production rate was improved from 3.29 mL H{sub 2}/optical density at 600 nm (OD{sub 600nm}) unit-h produced by WDHL under non-optimal conditions to 5.88 mL H{sub 2}/OD{sub 600nm} unit-h under optimal conditions. Using optimal initial conditions, galactose can be metabolized by WDHL strain. The maximum yield obtained was 2.74 mol H{sub 2}/mol lactose consumed, which is comparable with the yield reached in other hydrogen production processes with Clostridium sp. or mixed cultures. (author)

  13. Rapid establishment of thermophilic anaerobic microbial community during the one-step startup of thermophilic anaerobic digestion from a mesophilic digester.

    Science.gov (United States)

    Tian, Zhe; Zhang, Yu; Li, Yuyou; Chi, Yongzhi; Yang, Min

    2015-02-01

    The purpose of this study was to explore how fast the thermophilic anaerobic microbial community could be established during the one-step startup of thermophilic anaerobic digestion from a mesophilic digester. Stable thermophilic anaerobic digestion was achieved within 20 days from a mesophilic digester treating sewage sludge by adopting the one-step startup strategy. The succession of archaeal and bacterial populations over a period of 60 days after the temperature increment was followed by using 454-pyrosequencing and quantitative PCR. After the increase of temperature, thermophilic methanogenic community was established within 11 days, which was characterized by the fast colonization of Methanosarcina thermophila and two hydrogenotrophic methanogens (Methanothermobacter spp. and Methanoculleus spp.). At the same time, the bacterial community was dominated by Fervidobacterium, whose relative abundance rapidly increased from 0 to 28.52 % in 18 days, followed by other potential thermophilic genera, such as Clostridium, Coprothermobacter, Anaerobaculum and EM3. The above result demonstrated that the one-step startup strategy could allow the rapid establishment of the thermophilic anaerobic microbial community. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Effects of volatile fatty acids in biohydrogen effluent on biohythane production from palm oil mill effluent under thermophilic condition

    Directory of Open Access Journals (Sweden)

    Chonticha Mamimin

    2017-09-01

    Conclusion: Preventing the high concentration of butyric acid, and propionic acid in the hydrogenic effluent could enhance methane production in two-stage anaerobic digestion for biohythane production.

  15. An efficient Azorean thermophilic consortium for lignocellulosic biomass degradation

    OpenAIRE

    Martins, Rita; Teixeira, Mário; Toubarro, Duarte; Simões, Nelson; Domingues, Lucília; Teixeira, J. A.

    2015-01-01

    [Excerpt] Lignocellulosic plant biomass is being envisioned by biorefinery industry as an alternative to current petroleum platform because of the large scale availability, low cost and environmentally benign production. The industrial bioprocessing designed to transform lignocellulosic biomass into biofuels are harsh and the enzymatic reactions may be severely compromised reducing the production of fermentable sugars from lignocellulosic biomass. Thermophilic bacteria consortium are a potent...

  16. Community dynamics and glycoside hydrolase activities of thermophilic bacterial consortia adapted to switchgrass

    Energy Technology Data Exchange (ETDEWEB)

    Gladden, J.M.; Allgaier, M.; Miller, C.S.; Hazen, T.C.; VanderGheynst, J.S.; Hugenholtz, P.; Simmons, B.A.; Singer, S.W.

    2011-05-01

    Industrial-scale biofuel production requires robust enzymatic cocktails to produce fermentable sugars from lignocellulosic biomass. Thermophilic bacterial consortia are a potential source of cellulases and hemicellulases adapted to harsher reaction conditions than commercial fungal enzymes. Compost-derived microbial consortia were adapted to switchgrass at 60 C to develop thermophilic biomass-degrading consortia for detailed studies. Microbial community analysis using small-subunit rRNA gene amplicon pyrosequencing and short-read metagenomic sequencing demonstrated that thermophilic adaptation to switchgrass resulted in low-diversity bacterial consortia with a high abundance of bacteria related to thermophilic paenibacilli, Rhodothermus marinus, and Thermus thermophilus. At lower abundance, thermophilic Chloroflexi and an uncultivated lineage of the Gemmatimonadetes phylum were observed. Supernatants isolated from these consortia had high levels of xylanase and endoglucanase activities. Compared to commercial enzyme preparations, the endoglucanase enzymes had a higher thermotolerance and were more stable in the presence of 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]), an ionic liquid used for biomass pretreatment. The supernatants were used to saccharify [C2mim][OAc]-pretreated switchgrass at elevated temperatures (up to 80 C), demonstrating that these consortia are an excellent source of enzymes for the development of enzymatic cocktails tailored to more extreme reaction conditions.

  17. Thermophilic slurry-phase treatment of petroleum hydrocarbon waste sludges

    International Nuclear Information System (INIS)

    Castaldi, F.J.; Bombaugh, K.J.; McFarland, B.

    1995-01-01

    Chemoheterotrophic thermophilic bacteria were used to achieve enhanced hydrocarbon degradation during slurry-phase treatment of oily waste sludges from petroleum refinery operations. Aerobic and anaerobic bacterial cultures were examined under thermophilic conditions to assess the effects of mode of metabolism on the potential for petroleum hydrocarbon degradation. The study determined that both aerobic and anaerobic thermophilic bacteria are capable of growth on petroleum hydrocarbons. Thermophilic methanogenesis is feasible during the degradation of hydrocarbons when a strict anaerobic condition is achieved in a slurry bioreactor. Aerobic thermophilic bacteria achieved the largest apparent reduction in chemical oxygen demand, freon extractable oil, total and volatile solid,s and polycyclic aromatic hydrocarbons (PAHs) when treating oily waste sludges. The observed shift with time in the molecular weight distribution of hydrocarbon material was more pronounced under aerobic metabolic conditions than under strict anaerobic conditions. The changes in the hydrocarbon molecular weight distribution, infrared spectra, and PAH concentrations during slurry-phase treatment indicate that the aerobic thermophilic bioslurry achieved a higher degree of hydrocarbon degradation than the anaerobic thermophilic bioslurry during the same time period

  18. Continuous Hydrogen Production from Agricultural Wastewaters at Thermophilic and Hyperthermophilic Temperatures.

    Science.gov (United States)

    Ramos, Lucas Rodrigues; Silva, Edson Luiz

    2017-06-01

    The objective of this study was to investigate the effects of hydraulic retention time (HRT) (8 to 0.5 h) and temperature (55 to 75 °C) in two anaerobic fluidized bed reactors (AFBR) using cheese whey (AFBR-CW = 10,000 mg sugars L -1 ) and vinasse (AFBR-V = 10,000 mg COD L -1 ) as substrates. Decreasing the HRT to 0.5 h increased the hydrogen production rates in both reactors, with maximum values of 5.36 ± 0.81 L H 2 h -1 L -1 in AFBR-CW and 0.71 ± 0.16 L H 2 h -1 L -1 in AFBR-V. The optimal conditions for hydrogen production were the HRT of 4 h and temperature of 65 °C in AFBR-CW, observing maximum hydrogen yield (HY) of 5.51 ± 0.37 mmol H 2 g COD -1 . Still, the maximum HY in AFBR-V was 1.64 ± 0.22 mmol H 2 g COD -1 at 4 h and 55 °C. However, increasing the temperature to 75 °C reduced the hydrogen production in both reactors. Methanol and butyric, acetic, and lactic acids were the main metabolites at temperatures of 55 and 65 °C, favoring the butyric and acetic metabolic pathways of hydrogen production. The increased productions of lactate, propionate, and methanol at 75 °C indicate that the hydrogen-producing bacteria in the thermophilic inoculum were inhibited under hyperthermophilic conditions.

  19. Thermotoga lettingae sp. nov. : a novel thermophilic, methanol-degrading bacterium isolated from a thermophilic anaerobic reactor

    NARCIS (Netherlands)

    Balk, M.; Weijma, J.; Stams, A.J.M.

    2002-01-01

    A novel, anaerobic, non-spore-forming, mobile, Gram-negative, thermophilic bacterium, strain TMO(T), was isolated from a thermophilic sulfate-reducing bioreactor operated at 65 degrees C with methanol as the sole substrate. The G C content of the DNA of strain TMO(T) was 39.2 molÐThe optimum pH,

  20. Nickel-graphene nanocomposite as a novel supplement for enhancement of biohydrogen production from industrial wastewater containing mono-ethylene glycol

    International Nuclear Information System (INIS)

    Elreedy, Ahmed; Ibrahim, Eman; Hassan, Nazly; El-Dissouky, Ali; Fujii, Manabu; Yoshimura, Chihiro; Tawfik, Ahmed

    2017-01-01

    Highlights: • Ni-graphene nanocomposite (Ni-Gr NC) showed superiority in biohydrogenation process. • Ni-Gr NC dose of 60 mg/L exhibited the highest improvement (105%) in H_2 production. • H_2 production was improved by 67% compared with supplementation of Ni nanoparticles. • Graphene presence in Ni-Gr NC didn’t show additional inhibition at the higher doses. • Net profit from energy recovery, including nanomaterials cost, was improved by 21%. - Abstract: The impact of Ni nanoparticles (NPs) and Ni-graphene nanocomposite (Ni-Gr NC) on hydrogen production from industrial wastewater containing mono-ethylene glycol (MEG) via anaerobic digestion was investigated. Batch reactors were supplemented with different dosages of Ni NPs and Ni-Gr NC ranging from 0 to 100 mg/L. Maximum hydrogen yields (HYs) of 24.73 ± 1.12 and 41.28 ± 1.69 mL/gCOD_i_n_i_t_i_a_l were achieved at a dosage of 60 mg/L for Ni NPs and Ni-Gr NC, respectively. Substantial improvements of 23% and 105% in hydrogen production were registered at an optimum dosage of 60 mg/L for Ni NPs and Ni-Gr NC, respectively, compared with the control without nanomaterials addition. However, increasing the dosage of Ni NPs and Ni-Gr NC to 100 mg/L resulted in a significant decrease in HY to 20.80 ± 1.12 and 24.24 ± 1.13 mL/gCOD_i_n_i_t_i_a_l, respectively. A non-linear regression model revealed that the higher maximum hydrogen production (129% improvement) could be achieved at a dosage of 50 mg/L Ni-Gr NC and an initial pH of 5.0. Economic and environmental revenues due to bioenergy recovery from MEG-containing wastewater were also estimated.

  1. Characterization of cellulolytic enzymes and bioH2 production from anaerobic thermophilic Clostridium sp. TCW1.

    Science.gov (United States)

    Lo, Yung-Chung; Huang, Chi-Yu; Cheng, Chieh-Lun; Lin, Chiu-Yue; Chang, Jo-Shu

    2011-09-01

    A thermophilic anaerobic bacterium Clostridium sp. TCW1 was isolated from dairy cow dung and was used to produce hydrogen from cellulosic feedstock. Extracellular cellulolytic enzymes produced from TCW1 strain were identified as endoglucanases (45, 53 and 70 kDa), exoglucanase (70 kDa), xylanases (53 and 60 kDa), and β-glucosidase (45 kDa). The endoglucanase and xylanase were more abundant. The optimal conditions for H2 production and enzyme production of the TCW1 strain were the same (60 °C, initial pH 7, agitation rate of 200 rpm). Ten cellulosic feedstock, including pure or natural cellulosic materials, were used as feedstock for hydrogen production by Clostridium strain TCW1 under optimal culture conditions. Using filter paper at 5.0 g/L resulted in the most effective hydrogen production performance, achieving a H2 production rate and yield of 57.7 ml/h/L and 2.03 mol H2/mol hexose, respectively. Production of cellulolytic enzyme activities was positively correlated with the efficiency of dark-H2 fermentation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Fiscal 1997 survey report on a feasibility of international collaboration on bio-hydrogen R and D; 1997 nendo chosa hokokusho (bio suiso seizo gijutsu ni kakawaru kokusai kyoryoku kanosei chosa)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    R and D of the production technology of biohydrogen is an option effective for the world energy supply technology and the world environmental preservation technology in the 21st century. At present, a project named `R and D of the environment harmony type hydrogen production technology` tackles the R and D of the hydrogen production technology using photosynthetic microorganisms, and promotes the R and D in this field from both aspects of a basis and application as seen in a workshop held including interchanges with researchers and research institutes overseas. With the recently increasing interest in bio-hydrogen production technology also overseas, search and bleeding/improvement of microorganisms related to the hydrogen production and utilization technology of biomass have been advancing. For development in this field, it is necessary to construct a widespread research network and promote the comprehensive research and development. In this survey, most of the research institutes visited recognized an importance of international cooperation in this field and agreed to make future research interchanges in a wide range. Based on the survey, a feasibility of concrete international collaboration is searched. 146 refs., 2 figs., 11 tabs.

  3. Optimization of bioethanol production from carbohydrate rich wastes by extreme thermophilic microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Tomas, A.F.

    2013-05-15

    Second-generation bioethanol is produced from residual biomass such as industrial and municipal waste or agricultural and forestry residues. However, Saccharomyces cerevisiae, the microorganism currently used in industrial first-generation bioethanol production, is not capable of converting all of the carbohydrates present in these complex substrates into ethanol. This is in particular true for pentose sugars such as xylose, generally the second major sugar present in lignocellulosic biomass. The transition of second-generation bioethanol production from pilot to industrial scale is hindered by the recalcitrance of the lignocellulosic biomass, and by the lack of a microorganism capable of converting this feedstock to bioethanol with high yield, efficiency and productivity. In this study, a new extreme thermophilic ethanologenic bacterium was isolated from household waste. When assessed for ethanol production from xylose, an ethanol yield of 1.39 mol mol-1 xylose was obtained. This represents 83 % of the theoretical ethanol yield from xylose and is to date the highest reported value for a native, not genetically modified microorganism. The bacterium was identified as a new member of the genus Thermoanaerobacter, named Thermoanaerobacter pentosaceus and was subsequently used to investigate some of the factors that influence secondgeneration bioethanol production, such as initial substrate concentration and sensitivity to inhibitors. Furthermore, T. pentosaceus was used to develop and optimize bioethanol production from lignocellulosic biomass using a range of different approaches, including combination with other microorganisms and immobilization of the cells. T. pentosaceus could produce ethanol from a wide range of substrates without the addition of nutrients such as yeast extract and vitamins to the medium. It was initially sensitive to concentrations of 10 g l-1 of xylose and 1 % (v/v) ethanol. However, long term repeated batch cultivation showed that the strain

  4. Efficient hydrogen production from the lignocellulosic energy crop Miscanthus by the extreme thermophilic bacteria Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana

    Directory of Open Access Journals (Sweden)

    de Vrije Truus

    2009-06-01

    Full Text Available Abstract Background The production of hydrogen from biomass by fermentation is one of the routes that can contribute to a future sustainable hydrogen economy. Lignocellulosic biomass is an attractive feedstock because of its abundance, low production costs and high polysaccharide content. Results Batch cultures of Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana produced hydrogen, carbon dioxide and acetic acid as the main products from soluble saccharides in Miscanthus hydrolysate. The presence of fermentation inhibitors, such as furfural and 5-hydroxylmethyl furfural, in this lignocellulosic hydrolysate was avoided by the mild alkaline-pretreatment conditions at a low temperature of 75°C. Both microorganisms simultaneously and completely utilized all pentoses, hexoses and oligomeric saccharides up to a total concentration of 17 g l-1 in pH-controlled batch cultures. T. neapolitana showed a preference for glucose over xylose, which are the main sugars in the hydrolysate. Hydrogen yields of 2.9 to 3.4 mol H2 per mol of hexose, corresponding to 74 to 85% of the theoretical yield, were obtained in these batch fermentations. The yields were higher with cultures of C. saccharolyticus compared to T. neapolitana. In contrast, the rate of substrate consumption and hydrogen production was higher with T. neapolitana. At substrate concentrations exceeding 30 g l-1, sugar consumption was incomplete, and lower hydrogen yields of 2.0 to 2.4 mol per mol of consumed hexose were obtained. Conclusion Efficient hydrogen production in combination with simultaneous and complete utilization of all saccharides has been obtained during the growth of thermophilic bacteria on hydrolysate of the lignocellulosic feedstock Miscanthus. The use of thermophilic bacteria will therefore significantly contribute to the energy efficiency of a bioprocess for hydrogen production from biomass.

  5. Syntrophic co-culture of aerobic Bacillus and anaerobic Clostridium for bio-fuels and bio-hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Jui-Jen; Ho, Cheng-Yu.; Chen, Wei-En; Huang, Chieh-Chen [Department of Life Sciences, National Chung Hsing University, Taichung (China); Chou, Chia-Hung; Lay, Jiunn-Jyi [Department of Science and Technology, National Kaohsiung First University, Kaohsiung (China)

    2008-10-15

    By using brewery yeast waste and microflora from rice straw compost, an anaerobic semi-solid bio-hydrogen-producing system has been established. For the purpose of industrialization, the major players of both aerobic and anaerobic bacterial strains in the system were isolated and their combination for an effective production of bio-hydrogen and other bio-fuels was examined in this study. The phylogenetic analysis found that four anaerobic isolates (Clostridium beijerinckii L9, Clostridium diolis Z2, Clostridium roseum Z5-1, and C. roseum W8) were highly related with each other and belongs to the cluster I clostridia family, the family that many of solvent-producing strains included. On the other hand, one of the aerobic isolates, the Bacillus thermoamylovorans strain I, shown multiple extracellular enzyme activities including lipase, protease, {alpha}-amylase, pectinase and cellulase, was suggested as a good partner for creating an anaerobic environment and pre-saccharification of substrate for those co-cultured solventogenic clostridial strain. Among these clostridial strains, though C. beijerinckii L9 do not show as many extracellular enzyme activities as Bacillus, but it performs the highest hydrogen-producing ability. The original microflora can be updated to a syntrophic bacterial co-culture system contended only with B. thermoamylovorans I and C. beijerinckii L9. The combination of aerobic Bacillus and anaerobic Clostridium may play the key role for developing the industrialized bio-fuels and bio-hydrogen-producing system from biomass. (author)

  6. Performance evaluation and phylogenetic characterization of anaerobic fluidized bed reactors using ground tire and pet as support materials for biohydrogen production.

    Science.gov (United States)

    Barros, Aruana Rocha; Adorno, Maria Angela Tallarico; Sakamoto, Isabel Kimiko; Maintinguer, Sandra Imaculada; Varesche, Maria Bernadete Amâncio; Silva, Edson Luiz

    2011-02-01

    This study evaluated two different support materials (ground tire and polyethylene terephthalate [PET]) for biohydrogen production in an anaerobic fluidized bed reactor (AFBR) treating synthetic wastewater containing glucose (4000 mg L(-1)). The AFBR, which contained either ground tire (R1) or PET (R2) as support materials, were inoculated with thermally pretreated anaerobic sludge and operated at a temperature of 30°C. The AFBR were operated with a range of hydraulic retention times (HRT) between 1 and 8h. The reactor R1 operating with a HRT of 2h showed better performance than reactor R2, reaching a maximum hydrogen yield of 2.25 mol H(2)mol(-1) glucose with 1.3mg of biomass (as the total volatile solids) attached to each gram of ground tire. Subsequent 16S rRNA gene sequencing and phylogenetic analysis of particle samples revealed that reactor R1 favored the presence of hydrogen-producing bacteria such as Clostridium, Bacillus, and Enterobacter. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. Novel dark fermentation involving bioaugmentation with constructed bacterial consortium for enhanced biohydrogen production from pretreated sewage sludge

    Energy Technology Data Exchange (ETDEWEB)

    Kotay, Shireen Meher; Das, Debabrata [Department of Biotechnology, Indian Institute of Technology, Kharagpur (India)

    2009-09-15

    The present study summarizes the observations on various nutrient and seed formulation methods using sewage sludge that have been aimed at ameliorating the biohydrogen production potential. Pretreatment methods viz., acid/base treatment, heat treatment, sterilization, freezing-thawing, microwave, ultrasonication and chemical supplementation were attempted on sludge. It was observed that pretreatment was essential not only to reduce the needless, competitive microbial load but also to improve the nutrient solublization of sludge. Heat treatment at 121 C for 20 min was found to be most effective in reducing the microbial load by 98% and hydrolyzing the organic fraction of sludge. However, this pretreatment alone was either not sufficient or inconsistent in developing a suitable microbial consortium for hydrogen production. Hydrogen yield was found to improve 1.5-4 times upon inoculation with H{sub 2}-producing microorganisms. A defined microbial consortium was developed consisting of three established bacteria viz., Enterobacter cloacae IIT-BT 08, Citrobacter freundii IIT-BT L139 and Bacillus coagulans IIT-BT S1. Following pretreatments soluble proteins and lipids (the major component of the sludge) were also found to be consumed besides carbohydrates. This laid out the concurrent proteolytic/lipolytic ability of the developed H{sub 2}-producing consortium. 1:1:1 v/v ratio of these bacteria in consortium was found to give the maximum yield of H{sub 2} from sludge, 39.15 ml H{sub 2}/g COD{sub reduced}. 15%v/v dilution and supplementation with 0.5%w/v cane molasses prior to heat treatment was found to further improve the yield to 41.23 ml H{sub 2}/g COD{sub reduced}. (author)

  8. Bioprocess for the production of recombinant HAP phytase of the thermophilic mold Sporotrichum thermophile and its structural and biochemical characteristics.

    Science.gov (United States)

    Maurya, Anay Kumar; Parashar, Deepak; Satyanarayana, T

    2017-01-01

    Thermophilc mold Sporotrichum thermophile secretes an acidstable and thermostable phytase, which finds application as a food and feed additive because of its adequate thermostability, acid stability, protease insensitivity and broad substrate spectrum. Low extracellular phytase production by the mold is a major bottleneck for its application on a commercial scale. We have successfully overcome this problem by constitutive secretary expression of codon optimized rStPhy under glyceraldehyde phosphate dehydrogenase (GAP) promoter in Pichia pastoris. A ∼41-fold improvement in rStPhy production has been achieved. Circular Dichroism (CD) spectra revealed that rStPhy is composed of 26.65% α-helices, 5.26% β-sheets and 68.09% random coils at pH 5.0 and 60°C, the optima for the enzyme activity. The melting temperature (T m ) of the enzyme is ∼73°C. The 3D structure of rStPhy displayed characteristic signature sequences (RHGXRXP and HD) of HAP phytase. The catalytically important amino acids (Arg74, His75, Arg78, His368 and Asp369) were identified by docking and site directed mutagenesis. Fluorescence quenching by N-bromosuccinimide (NBS) and CsCl exposed tryptophan residues surrounded by negative charges, which play a key role in maintaining structural integrity of rStPhy. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Temporal change of composition and potential activity of the thermophilic archaeal community during the composting of organic material.

    Science.gov (United States)

    Thummes, Kathrin; Kämpfer, Peter; Jäckel, Udo

    2007-07-01

    To date, composting has been regarded as an aerobic process but it has been shown that composting piles are often sources of atmospheric methane. In order to gain a more comprehensive view on the diversity of methanogenic Archaea in compost, gas chromatographical methods and molecular cloning were used to study relationships of thermophilic archaeal communities and changes in methane production potential during compost maturation. According to the thermophilic methane production potential, wide differences could be detected between differently aged compost materials. In material derived from 3- and 4-week-old piles, low and no thermophilic methane production potential, respectively, was observed at 50 degrees C. Material from a 6-week-old pile showed the maximum methane production. With compost maturation, the production slowly decreased again with 6 weeks, 8 weeks, and mature compost showing an optimum methane production potential at 60 degrees C. At 70 degrees C, only 6-week-old material showed a comparable high production of methane. The 16S rRNA-based phylogenetic surveys revealed an increase of archaeal diversity with compost maturation. In the 6-week-old material, 86% of the sequences in the archaeal 16S rRNA library had the highest sequence similarities to Methanothermobacter spp. and the remaining 14% of the clones were related to Methanosarcina thermophila. Quantification of methanogens in 6-week-old material, on the basis of the methane production rate, resulted in values of about 2x10(7) cells per gram fresh weight. In 8-week-old and mature compost material, the proportion of sequences similar to Methanothermobacter spp. decreased to 34% and 0%, respectively. The mature compost material showed the highest variation in identified sequences, although 33% could be assigned to as yet uncultured Archaea (e.g. Rice cluster I, III, and IV). Our results indicate that compost harbours a diverse community of thermophilic methanogens, with changing composition

  10. Biological hydrogen production by dark fermentation: challenges and prospects towards scaled-up production.

    Science.gov (United States)

    RenNanqi; GuoWanqian; LiuBingfeng; CaoGuangli; DingJie

    2011-06-01

    Among different technologies of hydrogen production, bio-hydrogen production exhibits perhaps the greatest potential to replace fossil fuels. Based on recent research on dark fermentative hydrogen production, this article reviews the following aspects towards scaled-up application of this technology: bioreactor development and parameter optimization, process modeling and simulation, exploitation of cheaper raw materials and combining dark-fermentation with photo-fermentation. Bioreactors are necessary for dark-fermentation hydrogen production, so the design of reactor type and optimization of parameters are essential. Process modeling and simulation can help engineers design and optimize large-scale systems and operations. Use of cheaper raw materials will surely accelerate the pace of scaled-up production of biological hydrogen. And finally, combining dark-fermentation with photo-fermentation holds considerable promise, and has successfully achieved maximum overall hydrogen yield from a single substrate. Future development of bio-hydrogen production will also be discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Organic loading rates affect composition of soil-derived bacterial communities during continuous, fermentative biohydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Yonghua; Bruns, Mary Ann [Department of Crop and Soil Sciences, The Pennsylvania State University, University Park, PA 16802 (United States); Zhang, Husen; Salerno, Michael; Logan, Bruce E. [Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA 16802 (United States)

    2008-11-15

    Bacterial community composition during steady-state, fermentative H{sub 2} production was compared across a range of organic loading rates (OLRs) of 0.5-19 g COD l{sup -1} h{sup -1} in a 2-l continuous flow reactor at 30 C. The varied OLRs were achieved with glucose concentrations of 2.5-10 g l{sup -1} and hydraulic retention times of 1-10 h. The synthetic wastewater feed was amended with L-cysteine and maintained at a pH of 5.5. For each run at a given glucose concentration, the reactor was inoculated with an aliquot of well-mixed agricultural topsoil that had been heat-treated to reduce numbers of vegetative cells. At OLRs less than 2 g COD l{sup -1} h{sup -1}, DNA sequences from ribosomal RNA intergenic spacer analysis profiles revealed more diverse and variable populations (Selenomonas, Enterobacter, and Clostridium spp.) than were observed above 2 g COD l{sup -1} h{sup -1} (Clostridium spp. only). An isolate, LYH1, was cultured from a reactor sample (10 g glucose l{sup -1} at a 10-h HRT) on medium containing L-cysteine. In confirming H{sub 2} production by LYH1 in liquid batch culture, lag periods for H{sub 2} production in the presence and absence of L-cysteine were 5 and 50 h, respectively. The 16S rRNA gene sequence of LYH1 indicated that the isolate was a Clostridium sp. affiliated with RNA subcluster Ic, with >99% similarity to Clostridium sp. FRB1. In fluorescent in situ hybridization tests, an oligonucleotide probe complementary to the 16S rRNA of LYH1 hybridized with 90% of cells observed at an OLR of 2 g COD h{sup -1}, compared to 26% of cells at an OLR of 0.5 g COD l{sup -1} h{sup -1}. An OLR of 2 g COD l{sup -1} h{sup -1} appeared to be a critical threshold above which clostridia were better able to outcompete Enterobacteriaceae and other organisms in the mixed soil inoculum. Our results are discussed in light of other biohydrogen studies employing pure cultures and mixed inocula. (author)

  12. Thermophilic biofiltration of benzene and toluene.

    Science.gov (United States)

    Cho, Kyung-Suk; Yoo, Sun-Kyung; Ryu, Hee Wook

    2007-12-01

    In the current studies, we characterized the degradation of a hot mixture of benzene and toluene (BT) gases by a thermophilic biofilter using polyurethane as packing material and high-temperature compost as a microbial source. We also examined the effect of supplementing the biofilter with yeast extract (YE). We found that YE substantially enhanced microbial activity in the thermophilic biofilter. The degrading activity of the biofilter supplied with YE was stable during long-term operation (approximately 100 d) without accumulating excess biomass. The maximum elimination capacity (1,650 g x m(-3) h(-1)) in the biofilter supplemented with YE was 3.5 times higher than that in the biofilter without YE (470 g g x m(-3) h(-1)). At similar retention times, the capacity to eliminate BT for the YE-supplemented biofilter was higher than for previously reported mesophilic biofilters. Thus, thermophilic biofiltration can be used to degrade hydrophobic compounds such as a BT mixture. Finally, 16S rDNA polymerase chain reaction-DGGE (PCR-DGGE) fingerprinting revealed that the thermophilic bacteria in the biofilter included Rubrobacter sp. and Mycobacterium sp.

  13. Ruminal biohydrogenation kinetics of defatted flaxseed and sunflower is affected by heat treatment

    DEFF Research Database (Denmark)

    Lashkari, Saman; Hymøller, Lone; Jensen, Søren Krogh

    2017-01-01

    The effect of heat treatment on biohydrogenation of linoleic acid (LA) and linolenic acid (LNA) and formation of stearic acid (SA), cis-9, trans-11 conjugated LA (CLA), trans-10, cis-12 CLA and trans-vaccenic acid (VA) was studied in in vitro incubations with diluted rumen fluid as inoculum...

  14. A thermophilic ionic liquid-tolerant cellulase cocktail for the production of cellulosic biofuels.

    Directory of Open Access Journals (Sweden)

    Joshua I Park

    Full Text Available Generation of biofuels from sugars in lignocellulosic biomass is a promising alternative to liquid fossil fuels, but efficient and inexpensive bioprocessing configurations must be developed to make this technology commercially viable. One of the major barriers to commercialization is the recalcitrance of plant cell wall polysaccharides to enzymatic hydrolysis. Biomass pretreatment with ionic liquids (ILs enables efficient saccharification of biomass, but residual ILs inhibit both saccharification and microbial fuel production, requiring extensive washing after IL pretreatment. Pretreatment itself can also produce biomass-derived inhibitory compounds that reduce microbial fuel production. Therefore, there are multiple points in the process from biomass to biofuel production that must be interrogated and optimized to maximize fuel production. Here, we report the development of an IL-tolerant cellulase cocktail by combining thermophilic bacterial glycoside hydrolases produced by a mixed consortia with recombinant glycoside hydrolases. This enzymatic cocktail saccharifies IL-pretreated biomass at higher temperatures and in the presence of much higher IL concentrations than commercial fungal cocktails. Sugars obtained from saccharification of IL-pretreated switchgrass using this cocktail can be converted into biodiesel (fatty acid ethyl-esters or FAEEs by a metabolically engineered strain of E. coli. During these studies, we found that this biodiesel-producing E. coli strain was sensitive to ILs and inhibitors released by saccharification. This cocktail will enable the development of novel biomass to biofuel bioprocessing configurations that may overcome some of the barriers to production of inexpensive cellulosic biofuels.

  15. A Thermophilic Ionic Liquid-Tolerant Cellulase Cocktail for the Production of Cellulosic Biofuels

    Science.gov (United States)

    Park, Joshua I.; Steen, Eric J.; Burd, Helcio; Evans, Sophia S.; Redding-Johnson, Alyssa M.; Batth, Tanveer; Benke, Peter I.; D'haeseleer, Patrik; Sun, Ning; Sale, Kenneth L.; Keasling, Jay D.; Lee, Taek Soon; Petzold, Christopher J.; Mukhopadhyay, Aindrila; Singer, Steven W.; Simmons, Blake A.; Gladden, John M.

    2012-01-01

    Generation of biofuels from sugars in lignocellulosic biomass is a promising alternative to liquid fossil fuels, but efficient and inexpensive bioprocessing configurations must be developed to make this technology commercially viable. One of the major barriers to commercialization is the recalcitrance of plant cell wall polysaccharides to enzymatic hydrolysis. Biomass pretreatment with ionic liquids (ILs) enables efficient saccharification of biomass, but residual ILs inhibit both saccharification and microbial fuel production, requiring extensive washing after IL pretreatment. Pretreatment itself can also produce biomass-derived inhibitory compounds that reduce microbial fuel production. Therefore, there are multiple points in the process from biomass to biofuel production that must be interrogated and optimized to maximize fuel production. Here, we report the development of an IL-tolerant cellulase cocktail by combining thermophilic bacterial glycoside hydrolases produced by a mixed consortia with recombinant glycoside hydrolases. This enzymatic cocktail saccharifies IL-pretreated biomass at higher temperatures and in the presence of much higher IL concentrations than commercial fungal cocktails. Sugars obtained from saccharification of IL-pretreated switchgrass using this cocktail can be converted into biodiesel (fatty acid ethyl-esters or FAEEs) by a metabolically engineered strain of E. coli. During these studies, we found that this biodiesel-producing E. coli strain was sensitive to ILs and inhibitors released by saccharification. This cocktail will enable the development of novel biomass to biofuel bioprocessing configurations that may overcome some of the barriers to production of inexpensive cellulosic biofuels. PMID:22649505

  16. Diversity and ubiquity of thermophilic methanogenic archaea in temperate anoxic soils.

    Science.gov (United States)

    Wu, Xiao-Lei; Friedrich, Michael W; Conrad, Ralf

    2006-03-01

    Temperate rice field soil from Vercelli (Italy) contains moderately thermophilic methanogens of the yet uncultivated rice cluster I (RC-I), which become prevalent upon incubation at temperatures of 45-50 degrees C. We studied whether such thermophilic methanogens were ubiquitously present in anoxic soils. Incubation of different rice field soils (from Italy, China and the Philippines) and flooded riparian soils (from the Netherlands) at 45 degrees C resulted in vigorous CH(4) production after a lag phase of about 10 days. The archaeal community structure in the soils was analysed by terminal restriction fragment length polymorphism (T-RFLP) targeting the SSU rRNA genes retrieved from the soil, and by cloning and sequencing. Clones of RC-I methanogens mostly exhibited T-RF of 393 bp, but also terminal restriction fragment (T-RF) of 158 and 258 bp length, indicating a larger diversity than previously assumed. No RC-I methanogens were initially found in flooded riparian soils. However, these archaea became abundant upon incubation of the soil at 45 degrees C. Thermophilic RC-I methanogens were also found in the rice field soils from Pavia, Pila and Gapan. However, the archaeal communities in these soils also contained other methanogenic archaea at high temperature. Rice field soil from Buggalon, on the other hand, only contained thermophilic Methanomicrobiales rather than RC-I methanogens, and rice field soil from Jurong mostly Methanomicrobiales and only a few RC-I methanogens. The archaeal community of rice field soil from Zhenjiang almost exclusively consisted of Methanosarcinaceae when incubated at high temperature. Our results show that moderately thermophilic methanogens are common in temperate soils. However, RC-I methanogens are not always dominating or ubiquitous.

  17. Highly efficient production of optically pure l-lactic acid from corn stover hydrolysate by thermophilic Bacillus coagulans.

    Science.gov (United States)

    Ma, Kedong; Hu, Guoquan; Pan, Liwei; Wang, Zichao; Zhou, Yi; Wang, Yanwei; Ruan, Zhiyong; He, Mingxiong

    2016-11-01

    A thermophilic strain Bacillus coagulans (NBRC 12714) was employed to produce l-lactic acid from corn stover hydrolysate in membrane integrated continuous fermentation. The strain NBRC 12714 metabolized glucose and xylose by the Embden-Meyerhof-Parnas pathway (EMP) and the pentose phosphate pathway (PPP), producing l-lactic acid with optical purity >99.5%. The overall l-lactic acid titer of 92g/l with a yield of 0.91g/g and a productivity of 13.8g/l/h were achieved at a dilution rate of 0.15h(-1). The productivity obtained was 1.6-fold than that of conventional continuous fermentation without cell recycling, and also was the highest among the relevant studies ever reported. These results indicated that the process developed had great potential for economical industrial production of l-lactic acid from lignocellulosic biomass. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Hydrogen production from carrot pulp by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana

    NARCIS (Netherlands)

    Vrije, de G.J.; Budde, M.A.W.; Lips, S.J.J.; Bakker, R.R.; Mars, A.E.; Claassen, P.A.M.

    2010-01-01

    Hydrogen was produced from carrot pulp hydrolysate, untreated carrot pulp and (mixtures of) glucose and fructose by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana in pH-controlled bioreactors. Carrot pulp hydrolysate was obtained after enzymatic hydrolysis

  19. Thermophilic Anaerobic Degradation of Butyrate by a Butyrate-Utilizing Bacterium in Coculture and Triculture with Methanogenic Bacteria

    OpenAIRE

    Ahring, Birgitte K.; Westermann, Peter

    1987-01-01

    We studied syntrophic butyrate degradation in thermophilic mixed cultures containing a butyrate-degrading bacterium isolated in coculture with Methanobacterium thermoautotrophicum or in triculture with M. thermoautotrophicum and the TAM organism, a thermophilic acetate-utilizing methanogenic bacterium. Butyrate was β-oxidized to acetate with protons as the electron acceptors. Acetate was used concurrently with its production in the triculture. We found a higher butyrate degradation rate in th...

  20. Isolation and Screening of Thermophilic Bacilli from Compost for Electrotransformation and Fermentation: Characterization of Bacillus smithii ET 138 as a New Biocatalyst

    NARCIS (Netherlands)

    Bosma, E.F.; Weijer, van de A.H.P.; Daas, M.J.A.; Oost, van der J.; Vos, de W.M.; Kranenburg, van R.

    2015-01-01

    Thermophilic bacteria are regarded as attractive production organisms for cost-efficient conversion of renewable resources to green chemicals, but their genetic accessibility is a major bottleneck in developing them into versatile platform organisms. In this study, we aimed to isolate thermophilic,

  1. Chemoselective biohydrogenation of chalcone (2Ε)-3-(1,3-benzodioxole-5-yl)-1-phenyl-2-propen-1-one mediated by baker yeasts immobilized in polymeric supports

    International Nuclear Information System (INIS)

    Mundstock, Flavia L.S.; Silva, Vanessa D.; Nascimento, Maria da G.

    2009-01-01

    In this study, the yeast Saccharomyces cerevisiae, baker's yeast (BY) was immobilized in poly(ethylene oxide) (PEO), poly(vinyl alcohol) (PVA), sodium caseinate (SC), gelatin (G) films and in agar (A) and gelatin (G) gels, and used as a biocatalyst in the biohydrogenation reaction of (2Ε)-3-(1,3-benzodioxyl-5-yl)-1-phenyl-2-propen-1-one (1). The transformation of (1) into the corresponding dehydro chalcone (2) through biohydrogenation reactions was carried out in n-hexane at 25 or 35 deg C, for 4-48 h reaction. The product conversion, under different experimental conditions, was evaluated by hydrogen nuclear magnetic resonance, 1 H NMR.The highest conversion degrees were achieved using BY immobilized in agar gel, (29-47%), depending also on the temperature. Using BY immobilized in PEO, PVA, SC and G films, the conversion into (2) was lower (0-21%). The results show the feasibility of the use of BY immobilized in polymeric materials to reduce a,b-unsaturated carbonyl compounds. (author)

  2. Genome sequence and transcriptome analyses of the thermophilic zygomycete fungus Rhizomucor miehei.

    Science.gov (United States)

    Zhou, Peng; Zhang, Guoqiang; Chen, Shangwu; Jiang, Zhengqiang; Tang, Yanbin; Henrissat, Bernard; Yan, Qiaojuan; Yang, Shaoqing; Chen, Chin-Fu; Zhang, Bing; Du, Zhenglin

    2014-04-21

    The zygomycete fungi like Rhizomucor miehei have been extensively exploited for the production of various enzymes. As a thermophilic fungus, R. miehei is capable of growing at temperatures that approach the upper limits for all eukaryotes. To date, over hundreds of fungal genomes are publicly available. However, Zygomycetes have been rarely investigated both genetically and genomically. Here, we report the genome of R. miehei CAU432 to explore the thermostable enzymatic repertoire of this fungus. The assembled genome size is 27.6-million-base (Mb) with 10,345 predicted protein-coding genes. Even being thermophilic, the G + C contents of fungal whole genome (43.8%) and coding genes (47.4%) are less than 50%. Phylogenetically, R. miehei is more closerly related to Phycomyces blakesleeanus than to Mucor circinelloides and Rhizopus oryzae. The genome of R. miehei harbors a large number of genes encoding secreted proteases, which is consistent with the characteristics of R. miehei being a rich producer of proteases. The transcriptome profile of R. miehei showed that the genes responsible for degrading starch, glucan, protein and lipid were highly expressed. The genome information of R. miehei will facilitate future studies to better understand the mechanisms of fungal thermophilic adaptation and the exploring of the potential of R. miehei in industrial-scale production of thermostable enzymes. Based on the existence of a large repertoire of amylolytic, proteolytic and lipolytic genes in the genome, R. miehei has potential in the production of a variety of such enzymes.

  3. Survival of thermophilic and hyper-thermophilic microorganisms after exposure to UV-C, ionizing radiation and desiccation

    International Nuclear Information System (INIS)

    Beblo, K.; Wirth, R.; Huber, H.; Douki, T.; Schmalz, G.; Rachel, R.

    2011-01-01

    In this study, we investigated the ability of several (hyper-) thermophilic Archaea and phylo-genetically deep-branching thermophilic Bacteria to survive high fluences of monochromatic UV-C (254 nm) and high doses of ionizing radiation, respectively. Nine out of fourteen tested microorganisms showed a surprisingly high tolerance against ionizing radiation, and two species (Aquifex pyrophilus and Ignicoccus hospitalis) were even able to survive 20 kGy. Therefore, these species had a comparable survivability after exposure to ionizing radiation such as Deinococcus radiodurans. In contrast, there was nearly no difference in survival of the tested strains after exposure to UV-C under anoxic conditions. If the cells had been dried in advance of UV-C irradiation, they were more sensitive to UV-C radiation compared with cells irradiated in liquid suspension; this effect could be reversed by the addition of protective material like sulfidic ores before irradiation. By exposure to UV-C, photoproducts were formed in the DNA of irradiated Archaea and Bacteria. The distribution of the main photoproducts was species specific, but the amount of the photoproducts was only partly dependent on the applied fluence. Overall, our results show that tolerance to radiation seems to be a common phenomenon among thermophilic and hyper-thermophilic microorganisms. (authors)

  4. Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

    DEFF Research Database (Denmark)

    ISAKSEN, MF; BAK, F.; JØRGENSEN, BB

    1994-01-01

    sulfate-reducing bacteria was detected. Time course experiments showed constant sulfate reduction rates at 4 degrees C and 30 degrees C, whereas the activity at 60 degrees C increased exponentially after a lag period of one day. Thermophilic, endospore-forming sulfate-reducing bacteria, designated strain...... C to search for presence of psychrophilic, mesophilic and thermophilic sulfate-reducing bacteria. Detectable activity was initially only in the mesophilic range, but after a lag phase sulfate reduction by thermophilic sulfate-reducing bacteria were observed. No distinct activity of psychrophilic...... P60, were isolated and characterized as Desulfotomaculum kuznetsovii. The temperature response of growth and respiration of strain P60 agreed well with the measured sulfate reduction at 50 degrees-70 degrees C. Bacteria similar to strain P60 could thus be responsible for the measured thermophilic...

  5. Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

    DEFF Research Database (Denmark)

    ISAKSEN, MF; BAK, F.; JØRGENSEN, BB

    1994-01-01

    C to search for presence of psychrophilic, mesophilic and thermophilic sulfate-reducing bacteria. Detectable activity was initially only in the mesophilic range, but after a lag phase sulfate reduction by thermophilic sulfate-reducing bacteria were observed. No distinct activity of psychrophilic...... sulfate-reducing bacteria was detected. Time course experiments showed constant sulfate reduction rates at 4 degrees C and 30 degrees C, whereas the activity at 60 degrees C increased exponentially after a lag period of one day. Thermophilic, endospore-forming sulfate-reducing bacteria, designated strain...... P60, were isolated and characterized as Desulfotomaculum kuznetsovii. The temperature response of growth and respiration of strain P60 agreed well with the measured sulfate reduction at 50 degrees-70 degrees C. Bacteria similar to strain P60 could thus be responsible for the measured thermophilic...

  6. Potential improvement to a citric wastewater treatment plant using bio-hydrogen and a hybrid energy system

    Science.gov (United States)

    Zhi, Xiaohua; Yang, Haijun; Berthold, Sascha; Doetsch, Christian; Shen, Jianquan

    Treatment of highly concentrated organic wastewater is characterized as cost-consuming. The conventional technology uses the anaerobic-anoxic-oxic process (A 2/O), which does not produce hydrogen. There is potential for energy saving using hydrogen utilization associated with wastewater treatment because hydrogen can be produced from organic wastewater using anaerobic fermentation. A 50 m 3 pilot bio-reactor for hydrogen production was constructed in Shandong Province, China in 2006 but to date the hydrogen produced has not been utilized. In this work, a technical-economic model based on hydrogen utilization is presented and analyzed to estimate the potential improvement to a citric wastewater plant. The model assesses the size, capital cost, annual cost, system efficiency and electricity cost under different configurations. In a stand-alone situation, the power production from hydrogen is not sufficient for the required load, thus a photovoltaic array (PV) is employed as the power supply. The simulated results show that the combination of solar and bio-hydrogen has a much higher cost compared with the A 2/O process. When the grid is connected, the system cost achieved is 0.238 US t -1 wastewater, which is lower than 0.257 US t -1 by the A 2/O process. The results reveal that a simulated improvement by using bio-hydrogen and a FC system is effective and feasible for the citric wastewater plant, even when compared to the current cost of the A 2/O process. In addition, lead acid and vanadium flow batteries were compared for energy storage service. The results show that a vanadium battery has lower cost and higher efficiency due to its long lifespan and energy efficiency. Additionally, the cost distribution of components shows that the PV dominates the cost in the stand-alone situation, while the bio-reactor is the main cost component in the parallel grid.

  7. Thermophilic fungi in the new age of fungal taxonomy.

    Science.gov (United States)

    de Oliveira, Tássio Brito; Gomes, Eleni; Rodrigues, Andre

    2015-01-01

    Thermophilic fungi are of wide interest due to their potential to produce heat-tolerant enzymes for biotechnological processes. However, the taxonomy of such organisms remains obscure, especially given new developments in the nomenclature of fungi. Here, we examine the taxonomy of the thermophilic fungi most commonly used in industry in light of the recent taxonomic changes following the adoption of the International Code of Nomenclature for Algae, Fungi and Plants and also based on the movement One Fungus = One Name. Despite the widespread use of these fungi in applied research, several thermotolerant fungi still remain classified as thermophiles. Furthermore, we found that while some thermophilic fungi have had their genomes sequenced, many taxa still do not have barcode sequences of reference strains available in public databases. This lack of basic information is a limiting factor for the species identification of thermophilic fungi and for metagenomic studies in this field. Based on next-generation sequencing, such studies generate large amounts of data, which may reveal new species of thermophilic fungi in different substrates (composting systems, geothermal areas, piles of plant material). As discussed in this study, there are intrinsic problems associated with this method, considering the actual state of the taxonomy of thermophilic fungi. To overcome such difficulties, the taxonomic classification of this group should move towards standardizing the commonly used species names in industry and to assess the possibility of including new systems for describing species based on environmental sequences.

  8. Thermophilic amylase from Thermus sp. isolation and its potential application for bioethanol production

    Directory of Open Access Journals (Sweden)

    Amin Fatoni

    2012-11-01

    Full Text Available Limited reserves of fossil energy stimulate researchers to explore for a new alternative energy, such as bioethanol.A thermophilic amylase producing bacterium was isolated from local hot-springs and its characteristic and potential applicationfor bioethanol production was determined. The obtained amylase was studied to determine its optimum temperature, pH,enzymatic reaction time, and substrate concentration. Tapioca waste was used as the substrate to find the potential of theamylase for degrading starch into glucose, and then the process was continued by fermentation to produce bioethanol. Theamylase producer bacterium was proposed as genus Thermus sp. The crude amylase that was obtained has the optimumtemperature of 60°C and optimum pH of 8.0, optimum substrate concentration at 10% (w/w and optimum enzymatic reactiontime of 45 minutes. These enzymes convert the starches of waste tapioca at optimum conditions, with the result of 2.9%ethanol produced from raw materials.

  9. Thermophilic anaerobes in arctic marine sediments induced to mineralize complex organic matter at high temperature

    DEFF Research Database (Denmark)

    Hubert, Casey; Arnosti, Carol; Brüchert, Volker

    2010-01-01

    Marine sediments harbour diverse populations of dormant thermophilic bacterial spores that become active in sediment incubation experiments at much higher than in situ temperature. This response was investigated in the presence of natural complex organic matter in sediments of two Arctic fjords......, as well as with the addition of freeze-dried Spirulina or individual high-molecular-weight polysaccharides. During 50°C incubation experiments, Arctic thermophiles catalysed extensive mineralization of the organic matter via extracellular enzymatic hydrolysis, fermentation and sulfate reduction. This high...... reactivity determined the extent of the thermophilic response. Fjord sediments with higher in situ SRR also supported higher SRR at 50°C. Amendment with Spirulina significantly increased volatile fatty acids production and SRR relative to unamended sediment in 50°C incubations. Spirulina amendment also...

  10. Space agriculture for habitation on Mars with hyper-thermophilic aerobic composting bacteria

    Science.gov (United States)

    Space Agriculture Task Force; Ishikawa, Y.; Tomita-Yokotani, K.; Hashimoto, H.; Kitaya, Y.; Yamashita, M.; Nagatomo, M.; Oshima, T.; Wada, H.

    Manned Mars exploration, especially for extended periods of time, will require recycle of materials to support human life. Here, a conceptual design is developed for a Martian agricultural system driven by biologically regenerative functions. One of the core biotechnologies function is the use of hyper-thermophilic aerobic composting bacterial ecology. These thermophilic bacteria can play an important role in increasing the effectiveness of the processing of human metabolic waste and inedible biomass and of converting them to fertilizer for the cultivation of plants. This microbial technology has been already well established for the purpose of processing sewage and waste materials for small local communities in Japan. One of the characteristics of the technology is that the metabolic heat release that occurs during bacterial fermentation raises the processing temperature sufficiently high at 80 100 °C to support hyper-thermophilic bacteria. Such a hyper-thermophilic system is found to have great capability of decomposing wastes including even their normally recalcitrant components, in a reasonably short period of time and of providing a better quality of fertilizer as an end-product. High quality compost has been shown to be a key element in creating a healthy regenerative food production system. In ground-based studies, the soil microbial ecology after the addition of high quality compost was shown to improve plant growth and promote a healthy symbiosis of arbuscular mycorrhizal fungi. Another advantage of such high processing temperature is the ability to sterilize the pathogenic organisms through the fermentation process and thus to secure the hygienic safety of the system. Plant cultivation is one of the other major systems. It should fully utilize solar energy received on the Martian surface for supplying energy for photosynthesis. Subsurface water and atmospheric carbon dioxide mined on Mars should be also used in the plant cultivation system. Oxygen and

  11. Energetic and hydrogen limitations of thermophilic and hyperthermophilic methanogens

    Science.gov (United States)

    Stewart, L. C.; Holden, J. F.

    2013-12-01

    Deep-sea hydrothermal vents are a unique ecosystem, based ultimately not on photosynthesis but chemosynthetic primary production. This makes them an excellent analog environment for the early Earth, and for potential extraterrestrial habitable environments, such as those on Mars and Europa. The habitability of given vent systems for chemoautotrophic prokaryotes can be modeled energetically by estimating the available Gibbs energy for specific modes of chemoautotrophy, using geochemical data and mixing models for hydrothermal fluids and seawater (McCollom and Shock, 1997). However, modeling to date has largely not taken into account variation in organisms' energy demands in these environments. Controls on maintenance energies are widely assumed to be temperature-dependent, rising with increasing temperature optima (Tijhuis et al., 1993), and species-independent. The impacts of other environmental stressors and particular energy-gathering strategies on maintenance energies have not been investigated. We have undertaken culture-based studies of growth and maintenance energies in thermophilic and hyperthermophilic methanogenic (hydrogenotrophic) archaea from deep-sea hydrothermal vents to investigate potential controls on energy demands in hydrothermal vent microbes, and to quantify their growth and maintenance energies for future bioenergetic modeling. We have investigated trends in their growth energies over their full temperature range and a range of nitrogen concentrations, and in their maintenance energies at different hydrogen concentrations. Growth energies in these organisms appear to rise with temperature, but do not vary between hyperthermophilic and thermophilic methanogens. Nitrogen availability at tested levels (40μM - 9.4 mM) does not appear to affect growth energies in all but one tested organism. In continuous chemostat culture, specific methane production varied with hydrogen availability but was similar between a thermophilic and a hyperthermophilic

  12. Thermophilic fermentation of acetoin and 2,3-butanediol by a novel Geobacillus strain

    Directory of Open Access Journals (Sweden)

    Xiao Zijun

    2012-12-01

    Full Text Available Abstract Background Acetoin and 2,3-butanediol are two important biorefinery platform chemicals. They are currently fermented below 40°C using mesophilic strains, but the processes often suffer from bacterial contamination. Results This work reports the isolation and identification of a novel aerobic Geobacillus strain XT15 capable of producing both of these chemicals under elevated temperatures, thus reducing the risk of bacterial contamination. The optimum growth temperature was found to be between 45 and 55°C and the medium initial pH to be 8.0. In addition to glucose, galactose, mannitol, arabionose, and xylose were all acceptable substrates, enabling the potential use of cellulosic biomass as the feedstock. XT15 preferred organic nitrogen sources including corn steep liquor powder, a cheap by-product from corn wet-milling. At 55°C, 7.7 g/L of acetoin and 14.5 g/L of 2,3-butanediol could be obtained using corn steep liquor powder as a nitrogen source. Thirteen volatile products from the cultivation broth of XT15 were identified by gas chromatography–mass spectrometry. Acetoin, 2,3-butanediol, and their derivatives including a novel metabolite 2,3-dihydroxy-3-methylheptan-4-one, accounted for a total of about 96% of all the volatile products. In contrast, organic acids and other products were minor by-products. α-Acetolactate decarboxylase and acetoin:2,6-dichlorophenolindophenol oxidoreductase in XT15, the two key enzymes in acetoin metabolic pathway, were found to be both moderately thermophilic with the identical optimum temperature of 45°C. Conclusions Geobacillus sp. XT15 is the first naturally occurring thermophile excreting acetoin and/or 2,3-butanediol. This work has demonstrated the attractive prospect of developing it as an industrial strain in the thermophilic fermentation of acetoin and 2,3-butanediol with improved anti-contamination performance. The novel metabolites and enzymes identified in XT15 also indicated its

  13. In situ identification of the synthrophic protein fermentative Coprothermobacter spp. involved in the thermophilic anaerobic digestion process.

    Science.gov (United States)

    Gagliano, Maria Cristina; Braguglia, Camilla Maria; Rossetti, Simona

    2014-09-01

    Thermophilic bacteria have recently attracted great attention because of their potential application in improving different biochemical processes such as anaerobic digestion of various substrates, wastewater treatment or hydrogen production. In this study we report on the design of a specific 16S rRNA-targeted oligonucleotide probe for detecting members of Coprothermobacter genus characterized by a strong protease activity to degrade proteins and peptides. The newly designed CTH485 probe and helper probes hCTH429 and hCTH439 were optimized for use in fluorescence in situ hybridization (FISH) on thermophilic anaerobic sludge samples. In situ probing revealed that thermo-adaptive mechanisms shaping the 16S rRNA gene may affect the identification of thermophilic microorganisms. The novel developed FISH probe extends the possibility to study the widespread thermophilic syntrophic interaction of Coprothermobacter spp. with hydrogenotrophic methanogenic archaea, whose establishment is a great benefit for the whole anaerobic system. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  14. Rapid startup of thermophilic anaerobic digester to remove tetracycline and sulfonamides resistance genes from sewage sludge.

    Science.gov (United States)

    Xu, Rui; Yang, Zhao-Hui; Wang, Qing-Peng; Bai, Yang; Liu, Jian-Bo; Zheng, Yue; Zhang, Yan-Ru; Xiong, Wei-Ping; Ahmad, Kito; Fan, Chang-Zheng

    2018-01-15

    Spread of antibiotic resistance genes (ARGs) originating from sewage sludge is highlighted as an eminent health threat. This study established a thermophilic anaerobic digester using one-step startup strategy to quickly remove tetracycline and sulfonamides resistance genes from sewage sludge. At least 20days were saved in the startup period from mesophilic to thermophilic condition. Based on the results of 16S rDNA amplicons sequencing and predicted metagenomic method, the successful startup largely relied on the fast colonization of core thermophilic microbial population (e.g. Firmicutes, Proteobacteria, Actinobacteria). Microbial metabolic gene pathways for substrate degradation and methane production was also increased by one-step mode. In addition, real-time quantitative PCR approach revealed that most targeted tetracycline and sulfonamides resistance genes ARGs (sulI, tetA, tetO, tetX) were substantially removed during thermophilic digestion (removal efficiency>80%). Network analysis showed that the elimination of ARGs was attributed to the decline of their horizontal (intI1 item) and vertical (potential hosts) transfer-related elements under high-temperature. This research demonstrated that rapid startup thermophilic anaerobic digestion of wastewater solids would be a suitable technology for reducing quantities of various ARGs. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Energy transduction and transport processes in thermophilic bacteria

    NARCIS (Netherlands)

    Konings, W. N.; Tolner, B.; Speelmans, G.; Elferink, M. G. L.; de Wit, J. G.; Driessen, A. J. M.

    1992-01-01

    Bacterial growth at the extremes of temperature has remained a fascinating aspect in the study of membrane function and structure. The stability of the integral membrane proteins of thermophiles make them particularly amenable to study. Respiratory enzymes of thermophiles appear to be functionally

  16. Simultaneous biohydrogen production and starch wastewater treatment in an acidogenic expanded granular sludge bed reactor by mixed culture for long-term operation

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Wan-Qian; Ren, Nan-Qi; Liu, Bing-Feng; Ding, Jie [State Key Lab of Urban Water Resource and Environ, Harbin Institute of Technology, Harbin 150090 (China); Chen, Zhao-Bo [School of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Wang, Xiang-Jing; Xiang, Wen-Sheng [Research Center of Life Science and Biotechnology, Northeast Agricultural University, Harbin 150030 (China)

    2008-12-15

    The biofilm-based expanded granular sludge bed (EGSB) reactor was developed to treat starch-containing wastewater and simultaneously recovery hydrogen by mixed microbial culture. Granular activated carbon (GAC) was used as the support media. Operating at the temperature of 30 C for over 400 days (data not shown), the EGSB reactor presented high efficiency in hydrogen production and COD removal ability. The maximum hydrogen production rate (HPR) was found to be 1.64 L/L.d under the organic loading rate (OLR) of 1.0 g-starch/L.d, pH of 4.42 and HRT of 4 h. The hydrogen yield (HY) peaked at 0.11 L/g-COD, under the OLR of 0.5 g-starch/L.d, pH of 3.95 and HRT of 8 h. Hydrogen volume content was estimated to be 35-65% of the total biogas. The average COD removal rate was 31.1% under the OLR of 0.125 g-starch/L.d and HRT of 24 h. The main dissolved fermentation products were ethanol, acetate and butyrate. The average attached biofilm concentration was estimated to be 8.26 g/L, which favored hydrogen production and COD removal. It is speculated that the low pH operation in the present system would contribute significantly to lower the cost of alkaline amount required for pH control in the continuous operation, especially in the scale-up biohydrogen producing system. A model, built on the back propagation neural network (BPNN) theory and linear regression techniques, was developed for the simulation of EGSB system performance in the biodegradation of starch synthesis-based wastewater and simultaneous hydrogen production. The model well fitted the laboratory data, and could well simulate the removal of COD and the production of hydrogen in the EGSB reactor. (author)

  17. Highly thermostable xylanase production from a thermophilic Geobacillus sp. strain WSUCF1 utilizing lignocellulosic biomass

    Directory of Open Access Journals (Sweden)

    Aditya eBhalla

    2015-06-01

    Full Text Available AbstractEfficient enzymatic hydrolysis of lignocellulose to fermentable sugars requires a complete repertoire of biomass deconstruction enzymes. Hemicellulases play an important role in hydrolyzing hemicellulose component of lignocellulose to xylo-oligosaccharides and xylose. Thermostable xylanases have been a focus of attention as industrially important enzymes due to their long shelf life at high temperatures. Geobacillus sp. strain WSUCF1 produced thermostable xylanase activity (crude xylanase cocktail when grown on xylan or various inexpensive untreated and pretreated lignocellulosic biomasses such as prairie cord grass and corn stover. The optimum pH and temperature for the crude xylanase cocktail were 6.5 and 70ºC, respectively. The WSUCF1 crude xylanase was found to be highly thermostable with half-lives of 18 and 12 days at 60 and 70ºC, respectively. At 70ºC, rates of xylan hydrolysis were also found to be better with the WSUCF1 secretome than those with commercial enzymes, i.e., for WSUCF1 crude xylanase, CellicHTec2, and AccelleraseXY, the percent xylan conversions were 68.9, 49.4, and 28.92, respectively. To the best of our knowledge, WSUCF1 crude xylanase cocktail is among the most thermostable xylanases produced by thermophilic Geobacillus spp. and other thermophilic microbes (optimum growth temperature ≤70ºC. High thermostability, activity over wide range of temperatures, and better xylan hydrolysis than commercial enzymes make WSUCF1 crude xylanase suitable for thermophilic lignocellulose bioconversion processes.

  18. Differences in the catalytic mechanisms of mesophilic and thermophilic indole-3-glycerol phosphate synthase enzymes at their adaptive temperatures

    International Nuclear Information System (INIS)

    Zaccardi, Margot J.; Mannweiler, Olga; Boehr, David D.

    2012-01-01

    Highlights: ► Catalytic mechanisms of thermophilic–mesophilic enzymes may differ. ► Product release is rate-determining for thermophilic IGPS at low temperatures. ► But at higher temperatures, proton transfer from the general acid is rate-limiting. ► Rate-determining step is different still for mesophilic IGPS. ► Both chemical and physical steps of catalysis are important for temperature adaptation. -- Abstract: Thermophilic enzymes tend to be less catalytically-active at lower temperatures relative to their mesophilic counterparts, despite having very similar crystal structures. An often cited hypothesis for this general observation is that thermostable enzymes have evolved a more rigid tertiary structure in order to cope with their more extreme, natural environment, but they are also less flexible at lower temperatures, leading to their lower catalytic activity under mesophilic conditions. An alternative hypothesis, however, is that complementary thermophilic–mesophilic enzyme pairs simply operate through different evolutionary-optimized catalytic mechanisms. In this communication, we present evidence that while the steps of the catalytic mechanisms for mesophilic and thermophilic indole-3-glycerol phosphate synthase (IGPS) enzymes are fundamentally similar, the identity of the rate-determining step changes as a function of temperature. Our findings indicate that while product release is rate-determining at 25 °C for thermophilic IGPS, near its adaptive temperature (75 °C), a proton transfer event, involving a general acid, becomes rate-determining. The rate-determining steps for thermophilic and mesophilic IGPS enzymes are also different at their respective, adaptive temperatures with the mesophilic IGPS-catalyzed reaction being rate-limited before irreversible CO 2 release, and the thermophilic IGPS-catalyzed reaction being rate limited afterwards.

  19. Mesophilic and thermophilic anaerobic digestion of sulphate-containing wastewaters.

    Science.gov (United States)

    Colleran, E; Pender, S

    2002-01-01

    The effect of sulphate at an influent chemical oxygen demand (COD):sulphate ratio of 4 on the operational performance of anaerobic hybrid reactors treating molasses wastewater was investigated under mesophilic and thermophilic conditions in a long-term laboratory-scale study over a 1,081 day period. The presence of sulphate reduced the COD removal efficiency under both mesophilic and thermophilic conditions. At 55 degrees C, effluent acetate levels were consistently greater than 4000 mg l(-1) indicating that thermophilic acetate-utilising methane-producing bacteria (MPB) or sulphate-reducing bacteria (SRB) had not developed in the reactor under the conditions applied. At 37 degrees C, acetate was exclusively utilised by acetoclastic methanogens, whereas H2-utilising SRB predominated over H2-utilising MPB in the competition for hydrogen. By contrast, hydrogenotrophic MPB were shown to outcompete H2-utilising SRB during long-term thermophilic operation. 16SrDNA analysis of the seed sludge and reactor biomass on conclusion of the 37 degrees C and 55 degrees C trials illustrated that the dominant methanogen present on conclusion of the thermophilic trial in the absence of influent sulphate was related to Methanocorpusculum parvuum, and was capable of growth on both acetate and hydrogen. By contrast, an organism closely related to Methanobacterium thermoautotrophicum was the dominant methanogen present in the sulphate-fed reactor on completion of the thermophilic trial.

  20. Dose and time response of ruminally infused algae on rumen fermentation characteristics, biohydrogenation and Butyrivibrio group bacteria in goats.

    Science.gov (United States)

    Zhu, Honglong; Fievez, Veerle; Mao, Shengyong; He, Wenbo; Zhu, Weiyun

    2016-01-01

    Micro-algae could inhibit the complete rumen BH of dietary 18-carbon unsaturated fatty acid (UFAs). This study aimed to examine dose and time responses of algae supplementation on rumen fermentation, biohydrogenation and Butyrivibrio group bacteria in goats. Six goats were used in a repeated 3 × 3 Latin square design, and offered a fixed diet. Algae were infused through rumen cannule with 0 (Control), 6.1 (L-Alg), or 18.3 g (H-Alg) per day. Rumen contents were sampled on d 0, 3, 7, 14 and 20. H-Alg reduced total volatile fatty acid concentration and acetate molar proportion (P Algae induced a dose-dependent decrease in 18:0 and increased trans-18:1 in the ruminal content (P Algae had no effect on the abundances of Butyrivibrio spp. and Butyrivibrio proteoclasticus (P > 0.10), while H-Alg reduced the total bacteria abundance (P algae were related to the supplementation level, but there was no evidence of shift in ruminal biohydrogenation pathways towards t10-18:1. L-Alg mainly induced a transient effect on rumen biohydrogenation of 18-carbon UFAs, while H-Alg showed an acute inhibition and these effects were not associated with the known hydrogenating bacteria.

  1. Thermophilic (55 - 65°C) and extreme thermophilic (70 - 80°C) sulfate reduction in methanol and formate-fed UASB reactors

    NARCIS (Netherlands)

    Vallero, M.V.G.; Camarero, E.; Lettinga, G.; Lens, P.N.L.

    2004-01-01

    The feasibility of thermophilic (55-65 degreesC) and extreme thermophilic (70-80 degreesC) sulfate-reducing processes was investigated in three lab-scale upflow anaerobic sludge bed (UASB) reactors fed with either methanol or formate as the sole substrates and inoculated with mesophilic granular

  2. Improved productivity of poly (3-hydroxybutyrate) (PHB) in thermophilic Chelatococcus daeguensis TAD1 using glycerol as the growth substrate in a fed-batch culture.

    Science.gov (United States)

    Cui, Bin; Huang, Shaobin; Xu, Fuqian; Zhang, Ruijian; Zhang, Yongqing

    2015-07-01

    A particularly successful polyhydroxyalkanoate (PHA) in industrial applications is poly (3-hydroxybutyrate) (PHB). However, one of the major obstacles for wider application of PHB is the cost of its production and purification. Therefore, it is desirable to discover a method for producing PHB in large quantities at a competitive price. Glycerol is a cheap and widely used carbon source that can be applied in PHB production process. There are numerous advantages to operating fermentation at elevated temperatures; only several thermophilic bacteria are able to accumulate PHB when glycerol is the growth substrate. Here, we report on the possibility of increasing PHB production at low cost using thermophilic Chelatococcus daeguensis TAD1 when glycerol is the growth substrate in a fed-batch culture. We found that (1) excess glycerol inhibited PHB accumulation and (2) organic nitrogen sources, such as tryptone and yeast extract, promoted the growth of C. daeguensis TAD1. In the batch fermentation experiments, we found that using glycerol at low concentrations as the sole carbon source, along with the addition of mixed nitrate (NH4Cl, tryptone, and yeast extract), stimulated PHB accumulation in C. daeguensis TAD1. The results showed that the PHB productivity decreased in the following order: two-stage fed-batch fermentation > fed-batch fermentation > batch fermentation. In optimized culture conditions, a PHB amount of 17.4 g l(-1) was obtained using a two-stage feeding regimen, leading to a productivity rate of 0.434 g l(-1) h(-1), which is the highest productivity rate reported for PHB to date. This high PHB biosynthetic productivity could decrease the total production cost, allowing for further development of industrial applications of PHB.

  3. Differences in the catalytic mechanisms of mesophilic and thermophilic indole-3-glycerol phosphate synthase enzymes at their adaptive temperatures.

    Science.gov (United States)

    Zaccardi, Margot J; Mannweiler, Olga; Boehr, David D

    2012-02-10

    Thermophilic enzymes tend to be less catalytically-active at lower temperatures relative to their mesophilic counterparts, despite having very similar crystal structures. An often cited hypothesis for this general observation is that thermostable enzymes have evolved a more rigid tertiary structure in order to cope with their more extreme, natural environment, but they are also less flexible at lower temperatures, leading to their lower catalytic activity under mesophilic conditions. An alternative hypothesis, however, is that complementary thermophilic-mesophilic enzyme pairs simply operate through different evolutionary-optimized catalytic mechanisms. In this communication, we present evidence that while the steps of the catalytic mechanisms for mesophilic and thermophilic indole-3-glycerol phosphate synthase (IGPS) enzymes are fundamentally similar, the identity of the rate-determining step changes as a function of temperature. Our findings indicate that while product release is rate-determining at 25°C for thermophilic IGPS, near its adaptive temperature (75°C), a proton transfer event, involving a general acid, becomes rate-determining. The rate-determining steps for thermophilic and mesophilic IGPS enzymes are also different at their respective, adaptive temperatures with the mesophilic IGPS-catalyzed reaction being rate-limited before irreversible CO2 release, and the thermophilic IGPS-catalyzed reaction being rate limited afterwards. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. The influence of total solids content and initial pH on batch biohydrogen production by solid substrate fermentation of agroindustrial wastes.

    Science.gov (United States)

    Robledo-Narváez, Paula N; Muñoz-Páez, Karla M; Poggi-Varaldo, Hector M; Ríos-Leal, Elvira; Calva-Calva, Graciano; Ortega-Clemente, L Alfredo; Rinderknecht-Seijas, Noemí; Estrada-Vázquez, Carlos; Ponce-Noyola, M Teresa; Salazar-Montoya, J Alfredo

    2013-10-15

    Hydrogen is a valuable clean energy source, and its production by biological processes is attractive and environmentally sound and friendly. In México 5 million tons/yr of agroindustrial wastes are generated; these residues are rich in fermentable organic matter that can be used for hydrogen production. On the other hand, batch, intermittently vented, solid substrate fermentation of organic waste has attracted interest in the last 10 years. Thus the objective of our work was to determine the effect of initial total solids content and initial pH on H2 production in batch fermentation of a substrate that consisted of a mixture of sugarcane bagasse, pineapple peelings, and waste activated sludge. The experiment was a response surface based on 2(2) factorial with central and axial points with initial TS (15-35%) and initial pH (6.5-7.5) as factors. Fermentation was carried out at 35 °C, with intermittent venting of minireactors and periodic flushing with inert N2 gas. Up to 5 cycles of H2 production were observed; the best treatment in our work showed cumulative H2 productions (ca. 3 mmol H2/gds) with 18% and 6.65 initial TS and pH, respectively. There was a significant effect of TS on production of hydrogen, the latter decreased with initial TS increase from 18% onwards. Cumulative H2 productions achieved in this work were higher than those reported for organic fraction of municipal solid waste (OFMSW) and mixtures of OFMSW and fruit peels waste from fruit juice industry, using the same process. Specific energetic potential due to H2 in our work was attractive and fell in the high side of the range of reported results in the open literature. Batch dark fermentation of agrowastes as practiced in our work could be useful for future biorefineries that generate biohydrogen as a first step and could influence the management of this type of agricultural wastes in México and other countries and regions as well. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Cellulolytic potential of thermophilic species from four fungal orders

    DEFF Research Database (Denmark)

    Busk, Peter Kamp; Lange, Lene

    2013-01-01

    and in characterization of their industrially useful enzymes. In the present study we investigated the cellulolytic potential of 16 thermophilic fungi from the three ascomycete orders Sordariales, Eurotiales and Onygenales and from the zygomycete order Mucorales thus covering all fungal orders that include thermophiles....... Thermophilic fungi are the only described eukaryotes that can grow at temperatures above 45 ºC. All 16 fungi were able to grow on crystalline cellulose but their secreted enzymes showed widely different cellulolytic activities, pH optima and thermostabilities. Interestingly, in contrast to previous reports, we......Elucidation of fungal biomass degradation is important for understanding the turnover of biological materials in nature and has important implications for industrial biomass conversion. In recent years there has been an increasing interest in elucidating the biological role of thermophilic fungi...

  6. Thermophilic Fungi: Their Physiology and Enzymes†

    OpenAIRE

    Maheshwari, Ramesh; Bharadwaj, Girish; Bhat, Mahalingeshwara K.

    2000-01-01

    Thermophilic fungi are a small assemblage in mycota that have a minimum temperature of growth at or above 20 degrees C and a maximum temperature of growth extending Itp to 60 to 62 degrees C. As the only representatives of eukaryotic organisms that can grow at temperatures above 45 degrees C, the thermophilic fungi are valuable experimental systems for investigations of mechanisms that allow growth at moderately high temperature yet limit their growth beyond 60 to 62 degrees C. Although wides...

  7. Quantifying Contribution of Synthrophic Acetate Oxidation to Methane Production in Thermophilic Anaerobic Reactors by Membrane Inlet Mass Spectrometry

    DEFF Research Database (Denmark)

    Mulat, Daniel Girma; Ward, Alastair James; Adamsen, Anders Peter S.

    2014-01-01

    A unique method was developed and applied for monitoring methanogenesis pathways based on isotope labeled substrates combined with online membrane inlet quadrupole mass spectrometry (MIMS). In our study, a fermentation sample from a full-scale biogas plant fed with pig and cattle manure, maize...... silage, and deep litter was incubated with 100 mM of [2-13C] sodium acetate under thermophilic anaerobic conditions. MIMS was used to measure the isotopic distribution of dissolved CO2 and CH4 during the degradation of acetate, while excluding interference from water by applying a cold trap. After 6 days...... a new approach for online quantification of the relative contribution of methanogenesis pathways to methane production with a time resolution shorter than one minute. The observed contribution of SAO-HM to methane production under the tested conditions challenges the current widely accepted anaerobic...

  8. Bacillus coagulans MA-13: a promising thermophilic and cellulolytic strain for the production of lactic acid from lignocellulosic hydrolysate.

    Science.gov (United States)

    Aulitto, Martina; Fusco, Salvatore; Bartolucci, Simonetta; Franzén, Carl Johan; Contursi, Patrizia

    2017-01-01

    The transition from a petroleum-based economy towards more sustainable bioprocesses for the production of fuels and chemicals (circular economy) is necessary to alleviate the impact of anthropic activities on the global ecosystem. Lignocellulosic biomass-derived sugars are suitable alternative feedstocks that can be fermented or biochemically converted to value-added products. An example is lactic acid, which is an essential chemical for the production of polylactic acid, a biodegradable bioplastic. However, lactic acid is still mainly produced by Lactobacillus species via fermentation of starch-containing materials, the use of which competes with the supply of food and feed. A thermophilic and cellulolytic lactic acid producer was isolated from bean processing waste and was identified as a new strain of Bacillus coagulans , named MA-13. This bacterium fermented lignocellulose-derived sugars to lactic acid at 55 °C and pH 5.5. Moreover, it was found to be a robust strain able to tolerate high concentrations of hydrolysate obtained from wheat straw pre-treated by acid-catalysed (pre-)hydrolysis and steam explosion, especially when cultivated in controlled bioreactor conditions. Indeed, unlike what was observed in microscale cultivations (complete growth inhibition at hydrolysate concentrations above 50%), B. coagulans MA-13 was able to grow and ferment in 95% hydrolysate-containing bioreactor fermentations. This bacterium was also found to secrete soluble thermophilic cellulases, which could be produced at low temperature (37 °C), still retaining an optimal operational activity at 50 °C. The above-mentioned features make B. coagulans MA-13 an appealing starting point for future development of a consolidated bioprocess for production of lactic acid from lignocellulosic biomass, after further strain development by genetic and evolutionary engineering. Its optimal temperature and pH of growth match with the operational conditions of fungal enzymes hitherto

  9. The chemical properties and microbial community characterization of the thermophilic microaerobic pretreatment process.

    Science.gov (United States)

    Fu, Shan-Fei; He, Shuai; Shi, Xiao-Shuang; Katukuri, Naveen Reddy; Dai, Meng; Guo, Rong-Bo

    2015-12-01

    Thermophilic microaerobic pretreatment (TMP) was recently reported as an efficient pretreatment method of anaerobic digestion (AD). In this study, the chemical properties and microbial community were characterized to reveal how TMP working. Compared with thermophilic treatment under anaerobic condition (TMP0), cellulase activity obviously improved under microaerobic condition (TMP1), which was 10.9-49.0% higher than that of TMP0. Reducing sugar, SCOD and VFAs concentrations of TMP1 were 2.6-8.9%, 1.8-4.8% and 13.8-24% higher than those of TMP0, respectively. TMP gave obvious rise to phylum Firmicutes, which associated with extracellular enzymes production. The proportion of class Bacilli (belongs to phylum Firmicutes and mainly acts during hydrolysis) in TMP1 was 124.89% higher than that of TMP0, which reflected the greater hydrolytic ability under microaerobic condition. The improved abundance of phylum Firmicutes (especially class Bacilli, order Bacillales) under microaerobic condition could be the fundamental reason for the improved AD performance of thermophilic microaerobic pretreated corn straw. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Thermophillic Sidestream Anaerobic Membrane Bioreactors: The Shear Rate Dilemma

    NARCIS (Netherlands)

    Jeison, D.A.; Telkamp, P.; Lier, van J.B.

    2009-01-01

    Anaerobic biomass retention under thermophilic conditions has proven difficult. Membrane filtration can be used as alternative way to achieve high sludge concentrations. This research studied the feasibility of anaerobic membrane bioreactors (AnMBRs) under thermophilic conditions. A sidestream MBR

  11. Efficient production of L-lactic acid by newly isolated thermophilic Bacillus coagulans WCP10-4 with high glucose tolerance.

    Science.gov (United States)

    Zhou, Xingding; Ye, Lidan; Wu, Jin Chuan

    2013-05-01

    A thermophilic Bacillus coagulans WCP10-4 with tolerance to high concentration of glucose was isolated from soil and used to produce optically pure L-lactic acid from glucose and starch. In batch fermentation at pH 6.0, 240 g/L of glucose was completely consumed giving 210 g/L of L-lactic acid with a yield of 95 % and a productivity of 3.5 g/L/h. In simultaneous saccharification and fermentation at 50 °C without sterilizing the medium, 200 g/L of corn starch was completely consumed producing 202.0 g/L of L-lactic acid. To the best of our knowledge, this strain shows the highest osmotic tolerance to glucose among the strains ever reported for lactic acid production. This is the first report of simultaneous saccharification and fermentation of starch for lactic acid production under a non-sterilized condition.

  12. A robust nitrifying community in a bioreactor at 50 °C opens up the path for thermophilic nitrogen removal.

    Science.gov (United States)

    Courtens, Emilie Np; Spieck, Eva; Vilchez-Vargas, Ramiro; Bodé, Samuel; Boeckx, Pascal; Schouten, Stefan; Jauregui, Ruy; Pieper, Dietmar H; Vlaeminck, Siegfried E; Boon, Nico

    2016-09-01

    The increasing production of nitrogen-containing fertilizers is crucial to meet the global food demand, yet high losses of reactive nitrogen associated with the food production/consumption chain progressively deteriorate the natural environment. Currently, mesophilic nitrogen-removing microbes eliminate nitrogen from wastewaters. Although thermophilic nitrifiers have been separately enriched from natural environments, no bioreactors are described that couple these processes for the treatment of nitrogen in hot wastewaters. Samples from composting facilities were used as inoculum for the batch-wise enrichment of thermophilic nitrifiers (350 days). Subsequently, the enrichments were transferred to a bioreactor to obtain a stable, high-rate nitrifying process (560 days). The community contained up to 17% ammonia-oxidizing archaea (AOAs) closely related to 'Candidatus Nitrososphaera gargensis', and 25% nitrite-oxidizing bacteria (NOBs) related to Nitrospira calida. Incorporation of (13)C-derived bicarbonate into the respective characteristic membrane lipids during nitrification supported their activity as autotrophs. Specific activities up to 198±10 and 894±81 mg N g(-1) VSS per day for AOAs and NOBs were measured, where NOBs were 33% more sensitive to free ammonia. The NOBs were extremely sensitive to free nitrous acid, whereas the AOAs could only be inhibited by high nitrite concentrations, independent of the free nitrous acid concentration. The observed difference in product/substrate inhibition could facilitate the development of NOB inhibition strategies to achieve more cost-effective processes such as deammonification. This study describes the enrichment of autotrophic thermophilic nitrifiers from a nutrient-rich environment and the successful operation of a thermophilic nitrifying bioreactor for the first time, facilitating opportunities for thermophilic nitrogen removal biotechnology.

  13. Hydrophobic environment is a key factor for the stability of thermophilic proteins.

    Science.gov (United States)

    Gromiha, M Michael; Pathak, Manish C; Saraboji, Kadhirvel; Ortlund, Eric A; Gaucher, Eric A

    2013-04-01

    The stability of thermophilic proteins has been viewed from different perspectives and there is yet no unified principle to understand this stability. It would be valuable to reveal the most important interactions for designing thermostable proteins for such applications as industrial protein engineering. In this work, we have systematically analyzed the importance of various interactions by computing different parameters such as surrounding hydrophobicity, inter-residue interactions, ion-pairs and hydrogen bonds. The importance of each interaction has been determined by its predicted relative contribution in thermophiles versus the same contribution in mesophilic homologues based on a dataset of 373 protein families. We predict that hydrophobic environment is the major factor for the stability of thermophilic proteins and found that 80% of thermophilic proteins analyzed showed higher hydrophobicity than their mesophilic counterparts. Ion pairs, hydrogen bonds, and interaction energy are also important and favored in 68%, 50%, and 62% of thermophilic proteins, respectively. Interestingly, thermophilic proteins with decreased hydrophobic environments display a greater number of hydrogen bonds and/or ion pairs. The systematic elimination of mesophilic proteins based on surrounding hydrophobicity, interaction energy, and ion pairs/hydrogen bonds, led to correctly identifying 95% of the thermophilic proteins in our analyses. Our analysis was also applied to another, more refined set of 102 thermophilic-mesophilic pairs, which again identified hydrophobicity as a dominant property in 71% of the thermophilic proteins. Further, the notion of surrounding hydrophobicity, which characterizes the hydrophobic behavior of residues in a protein environment, has been applied to the three-dimensional structures of elongation factor-Tu proteins and we found that the thermophilic proteins are enriched with a hydrophobic environment. The results obtained in this work highlight the

  14. Evaluation of Myceliopthora thermophila as an Enzyme Factory for the Production of Thermophilic Cellulolytic Enzymes

    Directory of Open Access Journals (Sweden)

    Leonidas Matsakas

    2015-07-01

    Full Text Available Enzymatic hydrolysis is a key step in bioethanol production. Efficient hydrolysis requires a consortium of different enzymes that are able to hydrolyze cellulose and hemicellulose into fermentable sugars. Myceliopthora thermophila is a promising candidate for the production of thermophilic cellulolytic enzymes, the use of which could reduce the cost of ethanol production. The growth conditions of the fungus were optimized in order to achieve increased secretion of extracellular cellulases. Optimal conditions were found to be 7.0% w/v brewer’s spent grain as the carbon source and 0.4% w/v ammonium sulfate as the nitrogen source. The cellulases obtained were characterized for their optimum activity. The optimum temperature and pH for cellulase activity are 65 °C and pH 5.5, respectively. Studies on thermal inactivation of the crude extract showed that the cellulases of M. thermophila are stable for temperatures up to 60 °C. At this temperature the half-life was found to be as high as 27 h. Enzymatic hydrolysis of cellulose resulted in 31.4% hydrolysis yield at 60 °C after 24 h of incubation. Finally, the recalcitrance constant for cellulose and cellulose pretreated with ionic liquids was calculated to be 5.46 and 2.69, respectively.

  15. Effect of alkaline pretreatment on mesophilic and thermophilic anaerobic digestion of a submerged macrophyte: Inhibition and recovery against dissolved lignin during semi-continuous operation.

    Science.gov (United States)

    Koyama, Mitsuhiko; Watanabe, Keiko; Kurosawa, Norio; Ishikawa, Kanako; Ban, Syuhei; Toda, Tatsuki

    2017-08-01

    The long-term effect of alkaline pretreatment on semi-continuous anaerobic digestion (AD) of the lignin-rich submerged macrophyte Potamogeton maackianus was investigated using mesophilic and thermophilic conditions. In pretreated reactors, dissolved lignin accumulated to high levels. CH 4 production under the pretreated condition was higher than that of the untreated condition, but decreased from Days 22 (mesophilic) and 42 (thermophilic). However, CH 4 production subsequently recovered, although dissolved lignin accumulated. Further, the change in the microbial community was observed between conditions. These results suggest that dissolved lignin temporarily inhibited AD, although acclimatization to dissolved lignin occurred during long-term operation. During the steady state period, mesophilic conditions achieved a 42% increase in the CH 4 yield using pretreatment, while thermophilic conditions yielded an 8% increment. Because volatile fatty acids accumulated even after acclimatization during the thermophilic pretreated condition and was discharged with the effluent, improvement of the methanogenic step would enable enhanced CH 4 recovery. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Mesophilic and thermophilic anaerobic digestion of primary and secondary sludge. Effect of pre-treatment at elevated temperature

    DEFF Research Database (Denmark)

    Gavala, Hariklia N.; Yenal, U.; Skiadas, Ioannis V.

    2003-01-01

    Anaerobic digestion is an appropriate technique for the treatment of sludge before final disposal and it is employed worldwide as the oldest and most important process for sludge stabilization. In general, mesophilic anaerobic digestion of sewage sludge is more widely used compared to thermophilic...... digestion. Furthermore, thermal pre-treatment is suitable for the improvement of stabilization, enhancement of dewatering of the sludge, reduction of the numbers of pathogens and could be realized at relatively low cost especially at low temperatures. The present study investigates (a) the differences...... between mesophilic and thermophilic anaerobic digestion of sludge and (b) the effect of the pretreatment at 70 degreesC on mesophilic and thermophilic anaerobic digestion of primary and secondary sludge. The pretreatment step showed very positive effect on the methane potential and production rate upon...

  17. Biochemical characterization of thermophilic lignocellulose degrading enzymes and their potential for biomass bioprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Zambare, Vasudeo; Zambare, Archana; Christopher, Lew P. [Center for Bioprocessing Research & Development, South Dakota School of Mines and Technology, Rapid City 57701, SD (United States); Muthukumarappan, Kasiviswanath [Center for Bioprocessing Research & Development, South Dakota State University, Brookings 57007, SD (United States)

    2011-07-01

    A thermophilic microbial consortium (TMC) producing hydrolytic (cellulolytic and xylanolytic) enzymes was isolated from yard waste compost following enrichment with carboxymethyl cellulose and birchwood xylan. When grown on 5% lignocellulosic substrates (corn stover and prairie cord grass) at 60C, the thermophilic consortium produced more xylanase (up to 489 U/l on corn stover) than cellulase activity (up to 367 U/l on prairie cord grass). Except for the carboxymethyl cellulose-enriched consortium, thermo-mechanical extrusion pretreatment of these substrates had a positive effect on both activities with up to 13% and 21% increase in the xylanase and cellulase production, respectively. The optimum temperatures of the crude cellulase and xylanase were 60C and 70C with half-lives of 15 h and 18 h, respectively, suggesting higher thermostability for the TMC xylanase. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the crude enzyme exhibited protein bands of 25-77 kDa with multiple enzyme activities containing 3 cellulases and 3 xylanases. The substrate specificity declined in the following descending order: avicel>birchwood xylan>microcrystalline cellulose>filter paper>pine wood saw dust>carboxymethyl cellulose. The crude enzyme was 77% more active on insoluble than soluble cellulose. The Km and Vmax values were 36.49 mg/ml and 2.98 U/mg protein on avicel (cellulase), and 22.25 mg/ml and 2.09 U/mg protein, on birchwood xylan (xylanase). A total of 50 TMC isolates were screened for cellulase and xylanase secretion on agar plates. All single isolates showed significantly lower enzyme activities when compared to the thermophilic consortia. This is indicative of the strong synergistic interactions that exist within the thermophilic microbial consortium and enhance its hydrolytic capabilities. It was further demonstrated that the thermostable enzyme-generated lignocellulosic hydrolyzates can be fermented to bioethanol by a recombinant strain of Escherichia coli

  18. Trends of bio-hydrogen research and development in Europe. Report for the Research Institute of Innovative Technology for the Earth (RITE), Tokyo, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Huesing, B.

    1997-03-01

    Research into applied aspects of biological hydrogen production is carried out on a much lower level in Europe than basic hydrogenase research. However, the screening for good H{sub 2} producers, their cultivation, and the development of optimised culture and bioreactor systems has never been a strength in Europe. Although there are a few good groups in Europe major contributions in this field traditionally come from countries outside Europe. However, in the nineties a special application-oriented research subfield has begun to evolve in Europe: the use of genetic enginering to rationally optimise H{sub 2} producing organisms. The most important players who focus on green algae, cyanobacteria, and purple bacteria can be found in Germany, France, and Sweden. In European biohydrogen research, a large and diverse variety of organisms is investigated. Among the organisms most thoroughly studied are Alcaligenes eutrophus, Escherichia coli, Rhodobacter capsulatus, sulfate-reducing bacteria, and methanogenic bacteria. Moreover, a leading position has been obtained with respect to molecular genetics of green algae and cyanobacteria, albeit on a low level. The fact that such a broad range of diverse organisms is studied has advantages and disadvantages. A positive aspect is that the multitude of different approaches had led to several unexpected results which had otherwise been overlooked. On the other hand, an obvious link to biohydrogen production is often lacking. Moreover, there are many 'me-too' approaches and results in which previous findings are only reproduced for another organism as well. (orig.)

  19. A two-stage bioprocess for hydrogen and methane production from rice straw bioethanol residues.

    Science.gov (United States)

    Cheng, Hai-Hsuan; Whang, Liang-Ming; Wu, Chao-Wei; Chung, Man-Chien

    2012-06-01

    This study evaluates a two-stage bioprocess for recovering hydrogen and methane while treating organic residues of fermentative bioethanol from rice straw. The obtained results indicate that controlling a proper volumetric loading rate, substrate-to-biomass ratio, or F/M ratio is important to maximizing biohydrogen production from rice straw bioethanol residues. Clostridium tyrobutyricum, the identified major hydrogen-producing bacteria enriched in the hydrogen bioreactor, is likely utilizing lactate and acetate for biohydrogen production. The occurrence of acetogenesis during biohydrogen fermentation may reduce the B/A ratio and lead to a lower hydrogen production. Organic residues remained in the effluent of hydrogen bioreactor can be effectively converted to methane with a rate of 2.8 mmol CH(4)/gVSS/h at VLR of 4.6 kg COD/m(3)/d. Finally, approximately 75% of COD in rice straw bioethanol residues can be removed and among that 1.3% and 66.1% of COD can be recovered in the forms of hydrogen and methane, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Combined thermophilic aerobic process and conventional anaerobic digestion: effect on sludge biodegradation and methane production.

    Science.gov (United States)

    Dumas, C; Perez, S; Paul, E; Lefebvre, X

    2010-04-01

    The efficiency of hyper-thermophilic (65 degrees Celsius) aerobic process coupled with a mesophilic (35 degrees Celsius) digester was evaluated for the activated sludge degradation and was compared to a conventional mesophilic digester. For two Sludge Retention Time (SRT), 21 and 42 days, the Chemical Oxygen Demand (COD) solubilisation and biodegradation processes, the methanisation yield and the aerobic oxidation were investigated during 180 days. The best results were obtained at SRT of 44 days; the COD removal yield was 30% higher with the Mesophilic Anaerobic Digestion/Thermophilic Aerobic Reactor (MAD-TAR) co-treatment. An increase of the sludge intrinsic biodegradability is also observed (20-40%), showing that the unbiodegradable COD in mesophilic conditions becomes bioavailable. However, the methanisation yield was quite similar for both processes at a same SRT. Finally, such a process enables to divide by two the volume of digester with an equivalent efficiency. Copyright 2009 Elsevier Ltd. All rights reserved.

  1. Distinctive properties of high hydrogen producing extreme thermophiles, Caldicellulosiruptor saccharolyticus and Thermotaga elfii

    NARCIS (Netherlands)

    Niel, van E.W.J.; Budde, M.A.W.; Haas, de G.G.; Wal, van der F.J.; Claassen, P.A.M.; Stams, A.J.M.

    2002-01-01

    Growth and hydrogen production by two extreme thermophiles during sugar fermentation was investigated. In cultures of Caldicellulosiruptor saccharolyticus grown on sucrose and Thermotoga elfii grown on glucose stoichiometries of 3.3 mol of hydrogen and 2 mol of acetate per mol C6-sugar unit were

  2. Investigation of factors influencing biogas production in a large-scale thermophilic municipal biogas plant

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, Agnes; Jerome, Valerie; Freitag, Ruth [Bayreuth Univ. (Germany). Chair for Process Biotechnology; Burghardt, Diana; Likke, Likke; Peiffer, Stefan [Bayreuth Univ. (Germany). Dept. of Hydrology; Hofstetter, Eugen M. [RVT Process Equipment GmbH, Steinwiesen (Germany); Gabler, Ralf [BKW Biokraftwerke Fuerstenwalde GmbH, Fuerstenwalde (Germany)

    2009-10-15

    A continuously operated, thermophilic, municipal biogas plant was observed over 26 months (sampling twice per month) in regard to a number of physicochemical parameters and the biogas production. Biogas yields were put in correlation to parameters such as the volatile fatty acid concentration, the pH and the ammonium concentration. When the residing microbiota was classified via analysis of the 16S rRNA genes, most bacterial sequences matched with unidentified or uncultured bacteria from similar habitats. Of the archaeal sequences, 78.4% were identified as belonging to the genus Methanoculleus, which has not previously been reported for biogas plants, but is known to efficiently use H{sub 2} and CO{sub 2} produced by the degradation of fatty acids by syntrophic microorganisms. In order to further investigate the influence of varied amounts of ammonia (2-8 g/L) and volatile fatty acids on biogas production and composition (methane/CO{sub 2}), laboratory scale satellite experiments were performed in parallel to the technical plant. Finally, ammonia stripping of the process water of the technical plant was accomplished, a measure through which the ammonia entering the biogas reactor via the mash could be nearly halved, which increased the energy output of the biogas plant by almost 20%. (orig.)

  3. Hydrogen limitation and syntrophic growth among natural assemblages of thermophilic methanogens at deep-sea hydrothermal vents

    Directory of Open Access Journals (Sweden)

    Begüm D. Topçuoğlu

    2016-08-01

    Full Text Available Thermophilic methanogens are common autotrophs at hydrothermal vents, but their growth constraints and dependence on H2 syntrophy in situ are poorly understood. Between 2012 and 2015, methanogens and H2-producing heterotrophs were detected by growth at 80°C and 55°C at most diffuse (7-40°C hydrothermal vent sites at Axial Seamount. Microcosm incubations of diffuse hydrothermal fluids at 80°C and 55°C demonstrated that growth of thermophilic and hyperthermophilic methanogens is primarily limited by H2 availability. Amendment of microcosms with NH4+ generally had no effect on CH4 production. However, annual variations in abundance and CH4 production were observed in relation to the eruption cycle of the seamount. Microcosm incubations of hydrothermal fluids at 80°C and 55°C supplemented with tryptone and no added H2 showed CH4 production indicating the capacity in situ for methanogenic H2 syntrophy. 16S rRNA genes were found in 80°C microcosms from H2-producing archaea and H2-consuming methanogens, but not for any bacteria. In 55°C microcosms, sequences were found from the H2-producing bacteria and H2-consuming methanogens and sulfate-reducing bacteria. A co-culture of representative organisms showed that Thermococcus paralvinellae supported the syntrophic growth of Methanocaldococcus bathoardescens at 82°C and Methanothermococcus sp. strain BW11 at 60°C. The results demonstrate that modeling of subseafloor methanogenesis should focus primarily on H2 availability and temperature, and that thermophilic H2 syntrophy can support methanogenesis within natural microbial assemblages and may be an important energy source for thermophilic autotrophs in marine geothermal environments.

  4. Conversion of hemicellulose and D-xylose into ethanol by the use of thermophilic anaerobic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, Peter

    1998-02-01

    Ethanol is a CO{sub 2} neutral liquid fuel that can substitute the use of fossil fuels in the transportation sector, thereby reducing the CO{sub 2} emission to the atmoshpere. CO{sub 2} emission is suspected to contribute significantly to the so-called greenhouse effect, the global heating. Substrates for production of ethanol must be cheap and plentiful. This can be met by the use of lignocellulosic biomass such as willow, wheat straw, hardwood and softwood. However, the complexity of these polymeric substrates and the presence of several types of carbohydrates (glucose, xylose, mannose, galactose, arabinose) require additional treatment to release the useful carbohydrates and ferment the major carbohydrates fractions. The costs related to the ethanol-production must be kept at a minimum to be price competitive compared to gasoline. Therefore all of the carbohydrates present in lignocellulose need to be converted into ethanol. Glucose can be fermented to ethanol by yeast strains such as Saccharomyces cerevisiae, which, however, is unable to ferment the other major carbohydrate fraction, D-xylose. The need for a microorganism able to ferment D-xylose is therefore apparent. Thermophilic anaerobic ethanol producing bacteria can therefore be considered for fermentation of D-xylose. Screening of 130 thermophilic anaerobic bacterial strains, from hot-springs, mesophilic and thermophilic biogas plants, paper pulp industries and brewery waste, were examined for production of ethanol from D-xylose and wet-oxidized hemicellulose hydrolysate. Several strains were isolated and one particular strain was selected for best performance during the screening test. This strain was characterized as a new species, Thermoanaerobacter mathranii. However, the ethanol yield on wet-oxidized hemicellulose hydrolysate was not satisfactory. The bacterium was adapted by isolation of mutant strains, now resistant to the inhibitory compounds present in the hydrolysate. Growth and ethanol yield

  5. Thermophilic methanogenic Archaea in compost material: occurrence, persistence and possible mechanisms for their distribution to other environments.

    Science.gov (United States)

    Thummes, Kathrin; Schäfer, Jenny; Kämpfer, Peter; Jäckel, Udo

    2007-12-01

    Since compost is widely used as soil amendment and the fact that during the processing of compost material high amounts of microorganisms are released into the air, we investigated whether compost may act as a carrier for thermophilic methanogens to temperate soils. All eight investigated compost materials showed a clear methane production potential between 0.01 and 0.98 micromol CH(4) g dw(-1)h(-1) at 50 degrees C. Single strand conformation polymorphism (SSCP) and cloning analysis indicated the presence of Methanosarcina thermophila, Methanoculleus thermophilus, and Methanobacterium formicicum. Bioaerosols collected during the turning of a compost pile showed both a highly similar SSCP profile compared to the corresponding compost material and clear methane production during anoxic incubation in selective medium at 50 degrees C. Both observations indicated a considerable release of thermophilic methanogens into the air. To analyse the persistence of compost-borne thermophilic methanogens in temperate oxic soils, we therefore studied their potential activity in compost and compost/soil mixtures, which was brought to a meadow soil, as well as in an agricultural soil fertilised with compost. After 24h anoxic incubation at 50 degrees C, all samples containing compost showed a clear methanogenic activity, even 1 year after application. In combination with the in vitro observed resilience of the compost-borne methanogens against desiccation and UV radiation we assume that compost material acts as an effective carrier for the distribution of thermophilic methanogens by fertilisation and wind.

  6. The genotypic diversity and lipase production of some thermophilic bacilli from different genera

    OpenAIRE

    Koc, Melih; Cokmus, Cumhur; Cihan, Arzu Coleri

    2015-01-01

    Abstract Thermophilic 32 isolates and 20 reference bacilli were subjected to Rep-PCR and ITS-PCR fingerprinting for determination of their genotypic diversity, before screening lipase activities. By these methods, all the isolates and references could easily be differentiated up to subspecies level from each other. In screening assay, 11 isolates and 7 references were found to be lipase producing. Their extracellular lipase activities were measured quantitatively by incubating in both tributy...

  7. Comparing Residue Clusters from Thermophilic and Mesophilic Enzymes Reveals Adaptive Mechanisms.

    Science.gov (United States)

    Sammond, Deanne W; Kastelowitz, Noah; Himmel, Michael E; Yin, Hang; Crowley, Michael F; Bomble, Yannick J

    2016-01-01

    Understanding how proteins adapt to function at high temperatures is important for deciphering the energetics that dictate protein stability and folding. While multiple principles important for thermostability have been identified, we lack a unified understanding of how internal protein structural and chemical environment determine qualitative or quantitative impact of evolutionary mutations. In this work we compare equivalent clusters of spatially neighboring residues between paired thermophilic and mesophilic homologues to evaluate adaptations under the selective pressure of high temperature. We find the residue clusters in thermophilic enzymes generally display improved atomic packing compared to mesophilic enzymes, in agreement with previous research. Unlike residue clusters from mesophilic enzymes, however, thermophilic residue clusters do not have significant cavities. In addition, anchor residues found in many clusters are highly conserved with respect to atomic packing between both thermophilic and mesophilic enzymes. Thus the improvements in atomic packing observed in thermophilic homologues are not derived from these anchor residues but from neighboring positions, which may serve to expand optimized protein core regions.

  8. State of the art and future perspectives of thermophilic anaerobic digestion

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær; Mladenovska, Zuzana; Iranpour, R.

    2002-01-01

    The slate of the art of thermophilic digestion is discussed. Thermophilic digestion is a well established technology in Europe for treatment of mixtures of waste in common large scale biogas plants or for treatment of the organic fraction of municipal solid waste. Due to a large number of failures...... over time with thermophilic digestion of sewage sludge this process has lost its appeal in the USA. New demands on sanitation of biosolids before land use will, however, bring the attention back to the use of elevated temperatures during sludge stabilization. In the paper we show how the use of a start......-up strategy based on the actual activity of key microbes can be used to ensure proper and fast transfer of mesophilic digesters into thermophilic operation. Extreme thermophilic temperatures of 65degreesC or more may be necessary in the future to meet the demands for full sanitation of the waste material...

  9. Thermophilic enzymes and their applications in biocatalysis: a robust aldo-keto reductase.

    Science.gov (United States)

    Willies, Simon; Isupov, Misha; Littlechild, Jennifer

    2010-09-01

    Extremophiles are providing a good source of novel robust enzymes for use in biocatalysis for the synthesis of new drugs. This is particularly true for the enzymes from thermophilic organisms which are more robust than their mesophilic counterparts to the conditions required for industrial bio-processes. This paper describes a new aldo-keto reductase enzyme from a thermophilic eubacteria, Thermotoga maritima which can be used for the production of primary alcohols. The enzyme has been cloned and over-expressed in Escherichia coli and has been purified and subjected to full biochemical characterization. The aldo-keto reductase can be used for production of primary alcohols using substrates including benzaldehyde, 1,2,3,6-tetrahydrobenzaldehyde and para-anisaldehyde. It is stable up to 80 degrees C, retaining over 60% activity for 5 hours at this temperature. The enzyme at pH 6.5 showed a preference for the forward, carbonyl reduction. The enzyme showed moderate stability with organic solvents, and retained 70% activity in 20% (v/v) isopropanol or DMSO. These properties are favourable for its potential industrial applications.

  10. Thermophilic subseafloor microorganisms from the 1996 North Gorda Ridge eruption

    Science.gov (United States)

    Summit, Melanie; Baross, John A.

    1998-12-01

    High-temperature microbes were present in two hydrothermal event plumes (EP96A and B) resulting from the February-March 1996 eruptions along the North Gorda Ridge. Anaerobic thermophiles were cultured from 17 of 22 plume samples at levels exceeding 200 organisms per liter; no thermophiles were cultured from any of 12 samples of background seawater. As these microorganisms grow at temperatures of 50-90°C, they could not have grown in the event plume and instead most probably derived from a subseafloor environment tapped by the event plume source fluids. Event plumes are thought to derive from a pre-existing subseafloor fluid reservoir, which implies that these thermophiles are members of a native subseafloor community that was present before the eruptive event. Thermophiles also were cultured from continuous chronic-style hydrothermal plumes in April 1996; these plumes may have formed from cooling lava piles. To better understand the nutritional, chemical, and physical constraints of pre-eruptive crustal environments, seven coccoidal isolates from the two event plumes were partially characterized. Results from nutritional and phylogenetic studies indicate that these thermophiles are heterotrophic archaea that represent new species, and probably a new genus, within the Thermococcales.

  11. Comparison of the thermostability of cellulases from various thermophilic fungi

    Energy Technology Data Exchange (ETDEWEB)

    Wojtczak, G; Breuil, C; Yamada, J; Saddler, J N

    1987-10-01

    The cellulase activities of six thermophilic fungi were compared. Although the thermophilic fungi grew at relatively high temperatures (> 45/sup 0/C) the optimum temperatures for assaying the various cellulase activities were only slightly higher than the optimum temperatures for the mesophilic fungi, Trichoderma harzianum. Over prolonged incubation (> 24 h) the thermophilic strains demonstrated a higher hydrolytic potential as a result of the greater thermostability of the cellulase components. Although the extracellular cellulase activities had similar pH and temperature optima, in some cases the thermostability of the extracellular components were considerably lower.

  12. [Gradient elevation of temperature startup experiment of thermophilic ASBR treating thermal-hydrolyzed sewage sludge].

    Science.gov (United States)

    Ouyang, Er-Ming; Wang, Wei; Long, Neng; Li, Huai

    2009-04-15

    Startup experiment was conducted for thermophilic anaerobic sequencing batch reactor (ASBR) treating thermal-hydrolyzed sewage sludge using the strategy of the step-wise temperature increment: 35 degrees C-->40 degrees C-->47 degrees C-->53 degrees C. The results showed that the first step-increase (from 35 degrees C to 40 degrees C) and final step-increase (from 47 degrees C to 53 degrees C) had only a slight effect on the digestion process. The second step-increase (from 40 degrees C to 47 degrees C) resulted in a severe disturbance: the biogas production, methane content, CODeffluent and microorganism all have strong disturbance. At the steady stage of thermophilic ASBR treating thermal-hydrolyzed sewage sludge, the average daily gas production, methane content, specific methane production (CH4/CODinfluent), TCOD removal rate and SCOD removal rate were 2.038 L/d, 72.0%, 188.8 mL/g, 63.8%, 83.3% respectively. The results of SEM and DGGE indicated that the dominant species are obviously different at early stage and steady stage.

  13. Integrated systems for biopolymers and bioenergy production from organic waste and by-products: a review of microbial processes.

    Science.gov (United States)

    Pagliano, Giorgia; Ventorino, Valeria; Panico, Antonio; Pepe, Olimpia

    2017-01-01

    Recently, issues concerning the sustainable and harmless disposal of organic solid waste have generated interest in microbial biotechnologies aimed at converting waste materials into bioenergy and biomaterials, thus contributing to a reduction in economic dependence on fossil fuels. To valorize biomass, waste materials derived from agriculture, food processing factories, and municipal organic waste can be used to produce biopolymers, such as biohydrogen and biogas, through different microbial processes. In fact, different bacterial strains can synthesize biopolymers to convert waste materials into valuable intracellular (e.g., polyhydroxyalkanoates) and extracellular (e.g., exopolysaccharides) bioproducts, which are useful for biochemical production. In particular, large numbers of bacteria, including Alcaligenes eutrophus , Alcaligenes latus , Azotobacter vinelandii , Azotobacter chroococcum , Azotobacter beijerincki , methylotrophs, Pseudomonas spp., Bacillus spp., Rhizobium spp., Nocardia spp., and recombinant Escherichia coli , have been successfully used to produce polyhydroxyalkanoates on an industrial scale from different types of organic by-products. Therefore, the development of high-performance microbial strains and the use of by-products and waste as substrates could reasonably make the production costs of biodegradable polymers comparable to those required by petrochemical-derived plastics and promote their use. Many studies have reported use of the same organic substrates as alternative energy sources to produce biogas and biohydrogen through anaerobic digestion as well as dark and photofermentation processes under anaerobic conditions. Therefore, concurrently obtaining bioenergy and biopolymers at a reasonable cost through an integrated system is becoming feasible using by-products and waste as organic carbon sources. An overview of the suitable substrates and microbial strains used in low-cost polyhydroxyalkanoates for biohydrogen and biogas

  14. Growth and glucoamylase production by the thermophilic fungus Thermomyces lanuginosus in a synthetic medium

    Energy Technology Data Exchange (ETDEWEB)

    Haasum, I; Eriksen, S H; Jensen, B; Olsen, J [Copenhagen Univ. (Denmark). Dept. of General Microbiology

    1991-02-01

    The production of glucogenic amylase from the thermophilic fungus Thermomyces lanuginosus was studied in shake flasks and laboratory fermentors. As conidia were not able to germinate in media without yeast extract, pregerminated conidia were applied as inoculum. By this procedure it was possible to use different NH{sub 4}{sup +} salts as the sole source of nitrogen for growth and amylase formation in a synthetic medium. In pH-controlled fermentors a fourfold increase in the extracellular glucogenic amylase activity was obtained with (NH{sub 4})H{sub 2}PO{sub 4} as the nitrogen source as compared with yeast extract. However, by fractionation of these activities, comparable yields of partially purified glucoamylases were obtained. The glucoamylase preparation from fermentations with either of the nitrogen sources had a temperature optimum at 70deg C and showed similar thermal stability. By incubation without substrate at 60deg C, 90% of the activity was still present after 5 h. At 70deg C, 50% of the activity was retained after 30 min incubation. (orig.).

  15. Immobilization of anaerobic thermophilic bacteria for the production of cell-free thermostable. alpha. -amylases and pullulanases

    Energy Technology Data Exchange (ETDEWEB)

    Klingeberg, M [Goettingen Univ. (Germany, F.R.). Inst. fuer Mikrobiologie; Vorlop, K D [Technische Univ. Braunschweig (Germany, F.R.). Inst. fuer Technische Chemie; Antranikian, G [Technische Univ. Hamburg-Harburg, Hamburg (Germany, F. R.). Arbeitsbereich Biotechnologie 1

    1990-08-01

    For the production of cell-free thermostable {alpha}-amylases and pullulanases various anaerobic thermophilic bacteria that belong to the genera Clostridium and Thermoanaerobacter were immobilized in calcium alginate gel beads. The entrapment of bacteria was performed in full was well as in hollow spheres. An optimal limited medium, which avoided bacterial outgrowth, was developed for the cultivation of immobilized organisms at 60deg C using 0.4% starch as substrate. Compared to non-immobilized cells these techniques allowed a significant increase (up to 5.6-fold) in the specific activities of the extracellular enzymes formed. An increase in the productivity of extracellular enzymes was observed after immobilization of bacteria in full spheres. In the case of C. thermosaccharolyticum, for instance, the productivity was raised from 90 units (U)/10{sup 12} cells up to 700 U/10{sup 12} cells. Electrophoretic analysis of the secreted proteins showed that in all cases most of the amylolytic enzymes formed were released into the culture medium. Proteins that had a molecular mass of less than 450 000 daltons could easily diffuse through the gel matrix. Cultivation of immobilized bacteria in semi-continuous and fed-batch cultures was also accompanied by an elevation in the concentration of cell-free enzymes. (orig.).

  16. Open fermentative production of L-lactic acid with high optical purity by thermophilic Bacillus coagulans using excess sludge as nutrient.

    Science.gov (United States)

    Ma, Kedong; Maeda, Toshinari; You, Huiyan; Shirai, Yoshihito

    2014-01-01

    The development of a low-cost polymer-grade L-lactic acid production process was achieved in this study. Excess sludge hydrolyzate (ESH) was chosen as nutrient source for the objective of reducing nutrient cost in lactic acid production. 1% of ESH had high performance in lactic acid production relative to 2g/l yeast extract (YE) while the production cost of ESH was much lower than that of YE, indicating ESH was a promising substitute of YE. By employing a thermophilic strain of Bacillus coagulans (NBRC 12583), non-sterilized batch and repeated batch L-lactic acid fermentation was successfully performed, and the optical purity of L-lactic acid accumulated was more than 99%. Moreover, the factors associated with cell growth and lactic acid fermentation was investigated through a two-stage lactic acid production strategy. Oxygen played an important role in cell growth, and the optimal condition for cell growth and fermentation was pH 7.0 and 50°C. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Pathway engineering to improve ethanol production by thermophilic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Lynd, L.R.

    1998-12-31

    Continuation of a research project jointly funded by the NSF and DOE is proposed. The primary project goal is to develop and characterize strains of C. thermocellum and C. thermosaccharolyticum having ethanol selectivity similar to more convenient ethanol-producing organisms. An additional goal is to document the maximum concentration of ethanol that can be produced by thermophiles. These goals build on results from the previous project, including development of most of the genetic tools required for pathway engineering in the target organisms. As well, we demonstrated that the tolerance of C. thermosaccharolyticum to added ethanol is sufficiently high to allow practical utilization should similar tolerance to produced ethanol be demonstrated, and that inhibition by neutralizing agents may explain the limited concentrations of ethanol produced in studies to date. Task 1 involves optimization of electrotransformation, using either modified conditions or alternative plasmids to improve upon the low but reproducible transformation, frequencies we have obtained thus far.

  18. Comparing Residue Clusters from Thermophilic and Mesophilic Enzymes Reveals Adaptive Mechanisms.

    Directory of Open Access Journals (Sweden)

    Deanne W Sammond

    Full Text Available Understanding how proteins adapt to function at high temperatures is important for deciphering the energetics that dictate protein stability and folding. While multiple principles important for thermostability have been identified, we lack a unified understanding of how internal protein structural and chemical environment determine qualitative or quantitative impact of evolutionary mutations. In this work we compare equivalent clusters of spatially neighboring residues between paired thermophilic and mesophilic homologues to evaluate adaptations under the selective pressure of high temperature. We find the residue clusters in thermophilic enzymes generally display improved atomic packing compared to mesophilic enzymes, in agreement with previous research. Unlike residue clusters from mesophilic enzymes, however, thermophilic residue clusters do not have significant cavities. In addition, anchor residues found in many clusters are highly conserved with respect to atomic packing between both thermophilic and mesophilic enzymes. Thus the improvements in atomic packing observed in thermophilic homologues are not derived from these anchor residues but from neighboring positions, which may serve to expand optimized protein core regions.

  19. Thermophilic Campylobacter spp. in Danish broiler production: a cross-sectional survey and a retrospective analysis of risk factors for occurrence in broiler flocks

    DEFF Research Database (Denmark)

    Hald, Birthe; Wedderkopp, A.; Madsen, Mogens

    2000-01-01

    In order to elucidate the rate of thermophilic Campylobacter spp, carriage in Danish broiler production and to identify risk factors for occurrence of campylobacter in broiler flocks, a total of 88 randomly selected broiler flocks were tested for campylobacter infection, and a subsequent study...... of processing, 24% of the flocks were positive. The species distribution was 87% Campylobacter jejuni, 8% Campylobacter coli and 5% Campylobacter lari, The following parameters were identified as significant risk factors: lack of a hygiene barrier (odds ratio (OR) = 3.1, 1.1

  20. Conductive iron oxides accelerate thermophilic methanogenesis from acetate and propionate.

    Science.gov (United States)

    Yamada, Chihaya; Kato, Souichiro; Ueno, Yoshiyuki; Ishii, Masaharu; Igarashi, Yasuo

    2015-06-01

    Anaerobic digester is one of the attractive technologies for treatment of organic wastes and wastewater, while continuous development and improvements on their stable operation with efficient organic removal are required. Particles of conductive iron oxides (e.g., magnetite) are known to facilitate microbial interspecies electron transfer (termed as electric syntrophy). Electric syntrophy has been reported to enhance methanogenic degradation of organic acids by mesophilic communities in soil and anaerobic digester. Here we investigated the effects of supplementation of conductive iron oxides (magnetite) on thermophilic methanogenic microbial communities derived from a thermophilic anaerobic digester. Supplementation of magnetite accelerated methanogenesis from acetate and propionate under thermophilic conditions, while supplementation of ferrihydrite also accelerated methanogenesis from propionate. Microbial community analysis revealed that supplementation of magnetite drastically changed bacterial populations in the methanogenic acetate-degrading cultures, in which Tepidoanaerobacter sp. and Coprothermobacter sp. dominated. These results suggest that supplementation of magnetite induce electric syntrophy between organic acid-oxidizing bacteria and methanogenic archaea and accelerate methanogenesis even under thermophilic conditions. Findings from this study would provide a possibility for the achievement of stably operating thermophilic anaerobic digestion systems with high efficiency for removal of organics and generation of CH4. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  1. Ecology and biotechnological potential of the thermophilic fermentative Coprothermobacter spp.

    Science.gov (United States)

    Gagliano, M C; Braguglia, C M; Petruccioli, M; Rossetti, S

    2015-05-01

    Thermophilic bacteria have been isolated from several terrestrial, marine and industrial environments. Anaerobic digesters treating organic wastes are often an important source of these microorganisms, which catalyze a wide array of metabolic processes. Moreover, organic wastes are primarily composed of proteins, whose degradation is often incomplete. Coprothermobacter spp. are proteolytic anaerobic thermophilic microbes identified in several studies focused on the analysis of the microbial community structure in anaerobic thermophilic reactors. They are currently classified in the phylum Firmicutes; nevertheless, several authors showed that the Coprothermobacter group is most closely related to the phyla Dictyoglomi and Thermotoga. Since only a few proteolytic anaerobic thermophiles have been characterized so far, this microorganism has attracted the attention of researchers for its potential applications with high-temperature environments. In addition to proteolysis, Coprothermobacter spp. showed several metabolic abilities and may have a biotechnological application either as source of thermostable enzymes or as inoculum in anaerobic processes. Moreover, they can improve protein degradation by establishing a syntrophy with hydrogenotrophic archaea. To gain a better understanding of the phylogenesis, metabolic capabilities and adaptations of these microorganisms, it is of importance to better define the role in thermophilic environments and to disclose properties not yet investigated. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Decreasing ammonia inhibition in thermophilic methanogenic bioreactors using carbon fiber textiles.

    Science.gov (United States)

    Sasaki, Kengo; Morita, Masahiko; Hirano, Shin-ichi; Ohmura, Naoya; Igarashi, Yasuo

    2011-05-01

    Ammonia accumulation is one of the main causes of the loss of methane production observed during fermentation. We investigated the effect of addition of carbon fiber textiles (CFT) to thermophilic methanogenic bioreactors with respect to ammonia tolerance during the process of degradation of artificial garbage slurry, by comparing the performance of the reactors containing CFT with the performance of reactors without CFT. Under total ammonia-N concentrations of 3,000 mg L(-1), the reactors containing CFT were found to mediate stable removal of organic compounds and methane production. Under these conditions, high levels of methanogenic archaea were retained at the CFT, as determined by 16S rRNA gene analysis for methanogenic archaea. In addition, Methanobacterium sp. was found to be dominant in the suspended fraction, and Methanosarcina sp. was dominant in the retained fraction of the reactors with CFT. However, the reactors without CFT had lower rates of removal of organic compounds and production of methane under total ammonia-N concentrations of 1,500 mg L(-1). Under this ammonia concentration, a significant accumulation of acetate was observed in the reactors without CFT (130.0 mM), relative to the reactors with CFT (4.2 mM). Only Methanobacterium sp. was identified in the reactors without CFT. These results suggest that CFT enables stable proliferation of aceticlastic methanogens by preventing ammonia inhibition. This improves the process of stable garbage degradation and production of methane in thermophilic bioreactors that include high levels of ammonia.

  3. Cellulase enzyme production during continuous culture growth of Sporotrichum (Chrysosporium) thermophile

    Energy Technology Data Exchange (ETDEWEB)

    Cossar, D; Canevascini, G

    1986-07-01

    The cellulolytic fungus Sporotrichum (Chrysosporium) thermophile produces an extracellular cellobiose dehydrogenase during batch culture on cellulose or cellobiose. In chemostat culture at pH 5.6 on cellobiose this enzyme was produced in parallel with endo-cellulase. At pH 5.0 in continuous or fed-batch culture such a pattern was not evident. At constant growth rate in a chemostat with varying pH, activity of these enzymes was found to be poorly correlated. Thus the induction of cellobiose dehydrogenase shows a dependence on pH and cellobiose concentration which is different to that for endo-cellulase. The natural inducer of these enzymes and the role of cellubiose dehydrogenase remain to be elucidated.

  4. Optimization of extracellular thermophilic highly alkaline lipase from thermophilic bacillus sp isolated from hotspring of Arunachal Pradesh, India

    Science.gov (United States)

    Bora, Limpon; Bora, Minakshi

    2012-01-01

    Studies on lipase production were carried out with a bacterial strain (Bacillus sp LBN 2) isolated from soil sample of hotspring of Arunachal Pradesh, India. The cells were cultivated in a mineral medium with maximum production at 1% groundnut oil. The optimum temperature and initial medium pH for lipase production by the organism were 500C and 9.0 respectively. The molecular mass was found to be 33KDa by SDS PAGE. The optimal pH and temperature for activity were 10 and 600C respectively. The enzyme was found to be stable in the pH range of 8–11 with 90% retention of activity at pH 11. The enzyme retained 90% activity at 600C and 70% of activity at 700C for 1h. The lipase was found to be stable in acetone followed by ethanol. The present findings suggested the enzyme to be thermophilic alkaline lipase. PMID:24031801

  5. Enrichment of anaerobic syngas-converting bacteria from thermophilic bioreactor sludge.

    Science.gov (United States)

    Alves, Joana I; Stams, Alfons J M; Plugge, Caroline M; Alves, M Madalena; Sousa, Diana Z

    2013-12-01

    Thermophilic (55 °C) anaerobic microbial communities were enriched with a synthetic syngas mixture (composed of CO, H2 , and CO2 ) or with CO alone. Cultures T-Syn and T-CO were incubated and successively transferred with syngas (16 transfers) or CO (9 transfers), respectively, with increasing CO partial pressures from 0.09 to 0.88 bar. Culture T-Syn, after 4 successive transfers with syngas, was also incubated with CO and subsequently transferred (9 transfers) with solely this substrate - cultures T-Syn-CO. Incubation with syngas and CO caused a rapid decrease in the microbial diversity of the anaerobic consortium. T-Syn and T-Syn-CO showed identical microbial composition and were dominated by Desulfotomaculum and Caloribacterium species. Incubation initiated with CO resulted in the enrichment of bacteria from the genera Thermincola and Thermoanaerobacter. Methane was detected in the first two to three transfers of T-Syn, but production ceased afterward. Acetate was the main product formed by T-Syn and T-Syn-CO. Enriched T-CO cultures showed a two-phase conversion, in which H2 was formed first and then converted to acetate. This research provides insight into how thermophilic anaerobic communities develop using syngas/CO as sole energy and carbon source can be steered for specific end products and subsequent microbial synthesis of chemicals. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  6. A Novel Process Configuration for Anaerobic Digestion of Source-Sorted Household Waste Using Hyper-Thermophilic Post-Treatment

    DEFF Research Database (Denmark)

    Hartmann, H.; Ahring, Birgitte Kiær

    2005-01-01

    A novel reactor configuration was investigated for anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW). An anaerobic hyper-thermophilic (68°C) reactor R68 was implemented as a post–treatment step for the effluent of a thermophilic reactor R1 (55°C) in order to enhance...... hydrolysis of recalcitrant organic matter, improve sanitation and ease the stripping of ammonia from the reactor. The efficiency of the combined system was studied in terms of methane yield, volatile solids (VS) reduction and volatile fatty acid (VFA) production at different hydraulic retention times (HRT...

  7. Diversity of thermophilic archaeal isolates from hot springs in Japan

    Science.gov (United States)

    Itoh, Takashi; Yoshikawa, Naoto; Takashina, Tomonori

    2005-09-01

    In the light of the significance of extremophiles as model organisms to access possible extraterrestiral life, we provide a short review of the systematics of thermophilic Archaea, and introduce our exploratory research of novel thermophilic Archaea from hot springs in Japan. Up to date, we have isolated 162 strains of the thermophilic Archaea from hot springs in Japan by the enrichment method or the most probable number/PCR method, and the 16S rRNA gene sequences were determined to reveal their phylogenetic diversity. The sequence comparison illustrated that the isolates belonged to the orders Sulfolobales (117 isolates) , Thermoproteales (29 isolates), Desulfurococcales (8 isolates) and Thermoplasmatales (8 isolates), and there were six separate lineages representing new genera, and at least seven new species as predicted by the phylogenetic distance to known species. The collection of isolates not only included novel taxa but would give some implication for a necessity to reevaluate the current taxonomy of the thermophilic Archaea.

  8. Thermophilic and unusually acidophilic amylase produced by a thermophilic acidophilic bacillus sp

    Energy Technology Data Exchange (ETDEWEB)

    Uchino, F

    1982-01-01

    Bacillus sp. 11-1S, a thermophilic acidophilic bacterial strain, produced an extracellular amylase with unusual characteristics. The enzyme was purified 40-fold by SE-Sephadex column chromatography. The pH optimum for activity was 2.0, and substantial activity was noted in the pH range of 1.5-3.5. The optimal temperature was 70 degrees C, but the activity decreased markedly in lower reaction temperatures. Arrhenius plots of the reaction showed two straight lines intersecting at about 50 degrees C. The activity or stability of the enzyme was not likely to depend on Ca2+. The molecular weight of the enzyme was 54,000 calculated from the electrophoretic mobility. The enzyme behaved like an alpha-amylase (1,4-alpha-D- glucan glucanohydrolase, E.C. 3.2.1.1). About 34% of glucosidic linkages of soluble starch was hydrolyzed at 65 degrees C and pH 2.0, in 24 hours, and the major products were maltotriose and maltose. (Refs. 14).

  9. Optimization of biohydrogen and methane recovery within a cassava ethanol wastewater/waste integrated management system

    DEFF Research Database (Denmark)

    Wang, Wen; Xie, Li; Luo, Gang

    2012-01-01

    Thermophilic co-fermentation of cassava stillage (CS) and cassava excess sludge (CES) were investigated for hydrogen and methane production. The highest hydrogen yield (37.1 ml/g-total-VS added) was obtained at VSCS/VSCES of 7:1, 17% higher than that with CS digestion alone. The CES recycle......, and the acetobacteria percentage increased to 12.4% at VSCS/VSCES of 6:2. Relatively high efficient and stable hydrogen production was observed at VSCS/VSCES of 5:3 without pH adjusted and any pretreatment. The highest total energy yield, the highest COD and VS degradation were obtained at VSCS/VSCES of 7:1. GFC...... analysis indicated that the hydrolysis behavior was significantly improved by CES recycle at both hydrogen and methane production phase....

  10. Comparison of the microbial communities in solid-state anaerobic digestion (SS-AD) reactors operated at mesophilic and thermophilic temperatures.

    Science.gov (United States)

    Li, Yueh-Fen; Nelson, Michael C; Chen, Po-Hsu; Graf, Joerg; Li, Yebo; Yu, Zhongtang

    2015-01-01

    The microbiomes involved in liquid anaerobic digestion process have been investigated extensively, but the microbiomes underpinning solid-state anaerobic digestion (SS-AD) are poorly understood. In this study, microbiome composition and temporal succession in batch SS-AD reactors, operated at mesophilic or thermophilic temperatures, were investigated using Illumina sequencing of 16S rRNA gene amplicons. A greater microbial richness and evenness were found in the mesophilic than in the thermophilic SS-AD reactors. Firmicutes accounted for 60 and 82 % of the total Bacteria in the mesophilic and in the thermophilic SS-AD reactors, respectively. The genus Methanothermobacter dominated the Archaea in the thermophilic SS-AD reactors, while Methanoculleus predominated in the mesophilic SS-AD reactors. Interestingly, the data suggest syntrophic acetate oxidation coupled with hydrogenotrophic methanogenesis as an important pathway for biogas production during the thermophilic SS-AD. Canonical correspondence analysis (CCA) showed that temperature was the most influential factor in shaping the microbiomes in the SS-AD reactors. Thermotogae showed strong positive correlation with operation temperature, while Fibrobacteres, Lentisphaerae, Spirochaetes, and Tenericutes were positively correlated with daily biogas yield. This study provided new insight into the microbiome that drives SS-AD process, and the findings may help advance understanding of the microbiome in SS-AD reactors and the design and operation of SS-AD systems.

  11. Production of high concentration of l-lactic acid from oil palm empty fruit bunch by thermophilic Bacillus coagulans JI12.

    Science.gov (United States)

    Juturu, Veeresh; Wu, Jin Chuan

    2018-03-01

    Thermophilic Bacillus coagulans JI12 was used to ferment hemicellulose hydrolysate obtained by acid hydrolysis of oil palm empty fruit bunch at 50 °C and pH 6, producing 105.4 g/L of l-lactic acid with a productivity of 9.3 g/L/H by fed-batch fermentation under unsterilized conditions. Simultaneous saccharification and fermentation (SSF) was performed at pH 5.5 and 50 °C to convert both hemicellulose hydrolysate and cellulose-lignin complex in the presence of Cellic Ctec2 cellulases using yeast extract (20 g/L) as the nitrogen source, giving 114.0 g/L of l-lactic acid with a productivity of 5.7 g/L/H. The SSF was also conducted by replacing yeast extract with equal amount of dry Bakers' yeast, achieving 120.0 g/L of l-lactic acid with a productivity of 4.3 g/L/H. To the best of our knowledge, these lactic acid titers and productivities are the highest ever reported from lignocellulose hydrolysates. © 2017 International Union of Biochemistry and Molecular Biology, Inc.

  12. Biogas Upgrading via Hydrogenotrophic Methanogenesis in Two-Stage Continuous Stirred Tank Reactors at Mesophilic and Thermophilic Conditions

    DEFF Research Database (Denmark)

    Bassani, Ilaria; Kougias, Panagiotis; Treu, Laura

    2015-01-01

    This study proposes an innovative setup composed by two stage reactors to achieve biogas upgrading coupling the CO2 in the biogas with external H2 and subsequent conversion into CH4 by hydrogenotrophic methanogenesis. In this configuration, the biogas produced in the first reactor was transferred...... production and CO2 conversion was recorded. The consequent increase of pH did not inhibit the process indicating adaptation of microorganisms to higher pH levels. The effects of H2 on the microbial community were studied using high-throughput Illumina random sequences and full-length 16S rRNA genes extracted...... to the second one, where H2 was injected. This configuration was tested at both mesophilic and thermophilic conditions. After H2 addition, the produced biogas was upgraded to average CH4 content of 89% in the mesophilic reactor and 85% in the thermophilic. At thermophilic conditions, a higher efficiency of CH4...

  13. Establishment of markerless gene deletion tools in thermophilic Bacillus smithii and construction of multiple mutant strains

    NARCIS (Netherlands)

    Bosma, E.F.; Weijer, van de A.H.P.; Vlist, L.; Vos, de W.M.; Oost, van der J.; Kranenburg, van R.

    2015-01-01

    BACKGROUND: Microbial conversion of biomass to fuels or chemicals is an attractive alternative for fossil-based fuels and chemicals. Thermophilic microorganisms have several operational advantages as a production host over mesophilic organisms, such as low cooling costs, reduced contamination risks

  14. Force-dependent melting of supercoiled DNA at thermophilic temperatures.

    Science.gov (United States)

    Galburt, E A; Tomko, E J; Stump, W T; Ruiz Manzano, A

    2014-01-01

    Local DNA opening plays an important role in DNA metabolism as the double-helix must be melted before the information contained within may be accessed. Cells finely tune the torsional state of their genomes to strike a balance between stability and accessibility. For example, while mesophilic life forms maintain negatively superhelical genomes, thermophilic life forms use unique mechanisms to maintain relaxed or even positively supercoiled genomes. Here, we use a single-molecule magnetic tweezers approach to quantify the force-dependent equilibrium between DNA melting and supercoiling at high temperatures populated by Thermophiles. We show that negatively supercoiled DNA denatures at 0.5 pN lower tension at thermophilic vs. mesophilic temperatures. This work demonstrates the ability to monitor DNA supercoiling at high temperature and opens the possibility to perform magnetic tweezers assays on thermophilic systems. The data allow for an estimation of the relative energies of base-pairing and DNA bending as a function of temperature and support speculation as to different general mechanisms of DNA opening in different environments. Lastly, our results imply that average in vivo DNA tensions range between 0.3 and 1.1 pN. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Bio-degradation of oily food waste employing thermophilic bacterial strains.

    Science.gov (United States)

    Awasthi, Mukesh Kumar; Selvam, Ammaiyappan; Chan, Man Ting; Wong, Jonathan W C

    2018-01-01

    The objective of this work was to isolate a novel thermophilic bacterial strain and develop a bacterial consortium (BC) for efficient degradation oily food waste. Four treatments were designed: 1:1 mixture of pre-consumption food wastes (PrCFWs) and post-consumption food wastes (PCFWs) (T-1), 1:2 mixture of PrCFWs and PCFWs mixture (T-2), PrCFWs (T-3) and PCFWs (T-4). Equal quantity of BC was inoculated into each treatment to compare the oil degradation efficiency. Results showed that after 15days of incubation, a maximum oil reduction of 65.12±0.08% was observed in treatment T-4, followed by T-2 (55.44±0.12%), T-3 (54.79±0.04%) and T-1 (52.52±0.02%), while oil reduction was negligible in control. Results indicate that the development of oil utilizing thermophilic BC was more cost-effective in solving the degradation of oily food wastes and conversion into a stable end product. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Modulation of in vitro rumen biohydrogenation by Cistus ladanifer tannins compared with other tannin sources.

    Science.gov (United States)

    Costa, Mónica; Alves, Susana P; Cabo, Ângelo; Guerreiro, Olinda; Stilwell, George; Dentinho, Maria T; Bessa, Rui Jb

    2017-01-01

    Tannins are polyphenolic compounds able to modify the ruminal biohydrogenation (BH) of unsaturated fatty acids, but their activity may vary among different tannin sources. The effect of rockrose (Cistus ladanifer) on BH has never been compared with other more common tannin sources. Tannin extracts (100 g kg -1 substrate dry matter) from chestnut (CH), quebracho (QB), grape seed (GS) and rockrose (CL) were incubated in vitro for 6 h with ruminal fluid using as substrate a feed containing 60 g kg -1 of sunflower oil. A control treatment with no added tannins was also included. Compared with the control, GS and CL, but not CH and QB, increased (P 0.05) were observed for the disappearance of c9-18:1 and c9,c12,c15-18:3. The production of 18:0 was not different (P > 0.05) among treatments, although its proportion in the total BH products was lower (P < 0.05) for GS than for the other treatments. Condensed tannins from GS and, to a lesser extent, from CL stimulate the first steps of BH, without a clear inhibition of 18:0 production. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  17. Alcohol Selectivity in a Synthetic Thermophilic n-Butanol Pathway Is Driven by Biocatalytic and Thermostability Characteristics of Constituent Enzymes.

    Science.gov (United States)

    Loder, Andrew J; Zeldes, Benjamin M; Garrison, G Dale; Lipscomb, Gina L; Adams, Michael W W; Kelly, Robert M

    2015-10-01

    n-Butanol is generated as a natural product of metabolism by several microorganisms, but almost all grow at mesophilic temperatures. A synthetic pathway for n-butanol production from acetyl coenzyme A (acetyl-CoA) that functioned at 70°C was assembled in vitro from enzymes recruited from thermophilic bacteria to inform efforts for engineering butanol production into thermophilic hosts. Recombinant versions of eight thermophilic enzymes (β-ketothiolase [Thl], 3-hydroxybutyryl-CoA dehydrogenase [Hbd], and 3-hydroxybutyryl-CoA dehydratase [Crt] from Caldanaerobacter subterraneus subsp. tengcongensis; trans-2-enoyl-CoA reductase [Ter] from Spirochaeta thermophila; bifunctional acetaldehyde dehydrogenase/alcohol dehydrogenase [AdhE] from Clostridium thermocellum; and AdhE, aldehyde dehydrogenase [Bad], and butanol dehydrogenase [Bdh] from Thermoanaerobacter sp. strain X514) were utilized to examine three possible pathways for n-butanol. These pathways differed in the two steps required to convert butyryl-CoA to n-butanol: Thl-Hbd-Crt-Ter-AdhE (C. thermocellum), Thl-Hbd-Crt-Ter-AdhE (Thermoanaerobacter X514), and Thl-Hbd-Crt-Ter-Bad-Bdh. n-Butanol was produced at 70°C, but with different amounts of ethanol as a coproduct, because of the broad substrate specificities of AdhE, Bad, and Bdh. A reaction kinetics model, validated via comparison to in vitro experiments, was used to determine relative enzyme ratios needed to maximize n-butanol production. By using large relative amounts of Thl and Hbd and small amounts of Bad and Bdh, >70% conversion to n-butanol was observed in vitro, but with a 60% decrease in the predicted pathway flux. With more-selective hypothetical versions of Bad and Bdh, >70% conversion to n-butanol is predicted, with a 19% increase in pathway flux. Thus, more-selective thermophilic versions of Bad, Bdh, and AdhE are needed to fully exploit biocatalytic n-butanol production at elevated temperatures. Copyright © 2015, American Society for

  18. Assembly and multiple gene expression of thermophilic enzymes in Escherichia coli for in vitro metabolic engineering.

    Science.gov (United States)

    Ninh, Pham Huynh; Honda, Kohsuke; Sakai, Takaaki; Okano, Kenji; Ohtake, Hisao

    2015-01-01

    In vitro reconstitution of an artificial metabolic pathway is an emerging approach for the biocatalytic production of industrial chemicals. However, several enzymes have to be separately prepared (and purified) for the construction of an in vitro metabolic pathway, thereby limiting the practical applicability of this approach. In this study, genes encoding the nine thermophilic enzymes involved in a non-ATP-forming chimeric glycolytic pathway were assembled in an artificial operon and co-expressed in a single recombinant Escherichia coli strain. Gene expression levels of the thermophilic enzymes were controlled by their sequential order in the artificial operon. The specific activities of the recombinant enzymes in the cell-free extract of the multiple-gene-expression E. coli were 5.0-1,370 times higher than those in an enzyme cocktail prepared from a mixture of single-gene-expression strains, in each of which a single one of the nine thermophilic enzymes was overproduced. Heat treatment of a crude extract of the multiple-gene-expression cells led to the denaturation of indigenous proteins and one-step preparation of an in vitro synthetic pathway comprising only a limited number of thermotolerant enzymes. Coupling this in vitro pathway with other thermophilic enzymes including the H2 O-forming NADH oxidase or the malate/lactate dehydrogenase facilitated one-pot conversion of glucose to pyruvate or lactate, respectively. © 2014 Wiley Periodicals, Inc.

  19. An integrated system for hydrogen and methane production during landfill leachate treatment

    Energy Technology Data Exchange (ETDEWEB)

    Hafez, H.M.; Nakhla, G.; El Naggar, H. [Western Ontario Univ., London, ON (Canada). Dept. of Civil and Environmental Engineering

    2009-07-01

    This paper described a patent-pending integrated waste-to-energy system that includes a novel biohydrogen reactor with a gravity settler and a second stage conventional anaerobic digester for the production of methane gas. This chemical-free process was tested using a synthetic wastewater/leachate solution at 37 degrees C for 45 days. During the experimental period, the biohydrogenator steadily produced hydrogen (H{sub 2}) with no methane. The maximum hydrogen yield was 400 ml H{sub 2}/g glucose with an average of 345 ml H{sub 2}/g glucose, as compared to 141 and 118 ml H{sub 2}/g glucose for two consecutive runs done in parallel using a conventional continuously stirrer tank reactor. The maximum and average hydrogen production rates in the biohydrogen reactor with gravity settler were 22 and 19 L H{sub 2}/day, the maximum yield was 2.8 mol H{sub 2} /mol glucose higher than 1.6-2.3 mol H{sub 2}/mol glucose reported for continuous-flow reactors. The methane yield for the second stage approached a maximum value of 426 ml methane/g chemical oxygen demand (COD) removed.

  20. Tryptophan Oxidative Metabolism Catalyzed by : A Thermophile Isolated from Kuwait Soil Contaminated with Petroleum Hydrocarbons

    Directory of Open Access Journals (Sweden)

    Jassim M. Al-Hassan

    2011-01-01

    Full Text Available Tryptophan metabolism has been extensively studied in humans as well as in soil. Its metabolism takes place mainly through kynurenine pathway yielding hydroxylated, deaminated and many other products of physiological significance. However, tryptophan metabolism has not been studied in an isolated thermophilic bacterium. Geobacillus stearothermophilus is a local thermophile isolated from Kuwait desert soil contaminated with petroleum hydrocarbons. The bacterium grows well at 65 °C in 0.05 M phosphate buffer (pH 7, when supplied with organic compounds as a carbon source and has a good potential for transformation of steroids and related molecules. In the present study, we used tryptophan ethyl ester as a carbon source for the bacterium to study the catabolism of the amino acid at pH 5 and pH 7. In this endeavor, we have resolved twenty one transformation products of tryptophan by GC/LC and have identified them through their mass spectral fragmentation.

  1. Growth media in anaerobic fermentative processes: The underestimated potential of thermophilic fermentation and anaerobic digestion.

    Science.gov (United States)

    Hendriks, A T W M; van Lier, J B; de Kreuk, M K

    Fermentation and anaerobic digestion of organic waste and wastewater is broadly studied and applied. Despite widely available results and data for these processes, comparison of the generated results in literature is difficult. Not only due to the used variety of process conditions, but also because of the many different growth media that are used. Composition of growth media can influence biogas production (rates) and lead to process instability during anaerobic digestion. To be able to compare results of the different studies reported, and to ensure nutrient limitation is not influencing observations ascribed to process dynamics and/or reaction kinetics, a standard protocol for creating a defined growth medium for anaerobic digestion and mixed culture fermentation is proposed. This paper explains the role(s) of the different macro- and micronutrients, as well as the choices for a growth medium formulation strategy. In addition, the differences in nutrient requirements between mesophilic and thermophilic systems are discussed as well as the importance of specific trace metals regarding specific conversion routes and the possible supplementary requirement of vitamins. The paper will also give some insight into the bio-availability and toxicity of trace metals. A remarkable finding is that mesophilic and thermophilic enzymes are quite comparable at their optimum temperatures. This has consequences for the trace metal requirements of thermophiles under certain conditions. Under non-limiting conditions, the trace metal requirement of thermophilic systems is about 3 times higher than for mesophilic systems. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Appraisal of bio-hydrogen production schemes

    International Nuclear Information System (INIS)

    Bent Sorensen

    2006-01-01

    Work is ongoing on several schemes of biological hydrogen production. At one end is the genetic modification of biological systems (such as algae or cyanobacteria) to produce hydrogen from photosynthesis, instead of the energy-rich compounds (such as NADPH 2 ) normally constituting the endpoint of the transformations through the photo-systems. A second route is to collect and use the biomass produced by normal plant growth processes in a separate step that produces hydrogen. This may be done similar to biogas production by fermentation, where the endpoint is methane (plus CO 2 and minor constituents). Hydrogen could be the outcome of a secondary process starting from methane, involving any of the conventional methods of hydrogen production from natural gas. An alternative to fermentation is gasification of the biomass, followed by a shift-reaction leading to hydrogen. I compare advantages and disadvantages of these three routes, notably factors such as system efficiency, cost and environmental impacts, and also compare them to liquid biofuels. (author)

  3. Extracellular production of avicelase by the thermophilic soil bacterium Bacillus sp. SMIA-2

    Directory of Open Access Journals (Sweden)

    Luciana Ribeiro Coutinho Oliveira

    2014-05-01

    Full Text Available Nowadays, the isolation of new bacterial strains that produce enzymes with novel properties is a subject of great relevance to the scientific community. This study, in order to search for producers of new cellulase strains, investigated the avicelase production by thermophilic Bacillus sp. strain SMIA-2. The best avicelase activity was observed in a culture medium containing 0.5% (w v-1 avicel and 0.5% (w v-1 corn steep liquor with initial pH 7.5-8.0 incubated at 50oC. When avicel was replaced in the medium by the treated sugarcane bagasse (0.5%, w v-1 the avicelase activity levels were not affected. Studies on the avicelase characterization revealed that the optimum pH of the enzyme was found to be 8.5 and the enzyme retained more than 80% of its activity after incubation at room temperature for 2h at pH 6.5-8.5. The optimum temperature of this enzyme was 70oC and the enzyme retained 67% of the original activity after 20 min. of heat treatment at 70oC. Avicelase was stimulated by Mn2+ and Co2+, whereas Hg2+ greatly inhibited the enzyme activity

  4. Evidence for the Initial Steps of DHA Biohydrogenation by Mixed Ruminal Microorganisms from Sheep Involves Formation of Conjugated Fatty Acids.

    Science.gov (United States)

    Aldai, Noelia; Delmonte, Pierluigi; Alves, Susana P; Bessa, Rui J B; Kramer, John K G

    2018-01-31

    Incubation of DHA with sheep rumen fluid resulted in 80% disappearance in 6 h. The products were analyzed as their fatty acid (FA) methyl esters by GC-FID on SP-2560 and SLB-IL111 columns. The GC-online reduction × GC and GC-MS techniques demonstrated that all DHA metabolites retained the C22 structure (no evidence of chain-shortening). Two new transient DHA products were identified: mono-trans methylene interrupted-DHA and monoconjugated DHA (MC-DHA) isomers. Identification of MC-DHA was confirmed by their predicted elution using equivalent chain length differences from C18 FA, their molecular ions, and the 22:5 products formed which were the most abundant at 6 h. The 22:5 structures were established by fragmentation of their 4,4-dimethyloxazoline derivatives, and all 22:5 products contained an isolated double bond, suggesting formation via MC-DHA. The most abundant c4,c7,c10,t14,c19-22:5 appeared to be formed by unknown isomerases. Results suggest that the initial biohydrogenation of DHA was analogous to that of C18 FA.

  5. Exogenous cellulases of thermophilic micromycetes. Pt. 1. Selection of producers

    Energy Technology Data Exchange (ETDEWEB)

    Kvesitadze, G; Kvachadze, L; Aleksidze, T; Chartishvili, D K

    1986-01-01

    More than 600 micromycetes - representatives of different genera have been investigated for their ability to produce exogenous cellulases. Most of the investigated cultures were found to produce these enzymes, 24 cultures being thermophilic, and 18 thermotolerant. Cellulase or its derivatives proved to be the most favourable carbon source for cellulase secretion. None of the thermophilic cultures studied manifested the ability of exogenous exoglucanase biosynthesis. Using UV-rays as mutagen, a mutant strain A. terreus T-49 has been obtained being characterized by an increased endo-glucanase and cellobiase activity, as compared to the initial strains. The cellulase preparations of thermophilic micromycetes contain one cellulasic component: endo-glucanase, or two: endo-glucanase and cellobiase.

  6. Production, purification, and characterization of lipase from thermophilic and alkaliphilic Bacillus coagulans BTS-3.

    Science.gov (United States)

    Kumar, Satyendra; Kikon, Khyodano; Upadhyay, Ashutosh; Kanwar, Shamsher S; Gupta, Reena

    2005-05-01

    A thermophilic isolate Bacillus coagulans BTS-3 produced an extracellular alkaline lipase, the production of which was substantially enhanced when the type of carbon source, nitrogen source, and the initial pH of culture medium were consecutively optimized. Lipase activity 1.16 U/ml of culture medium was obtained in 48 h at 55 degrees C and pH 8.5 with refined mustard oil as carbon source and a combination of peptone and yeast extract (1:1) as nitrogen sources. The enzyme was purified 40-fold to homogeneity by ammonium sulfate precipitation and DEAE-Sepharose column chromatography. Its molecular weight was 31 kDa on SDS-PAGE. The enzyme showed maximum activity at 55 degrees C and pH 8.5, and was stable between pH 8.0 and 10.5 and at temperatures up to 70 degrees C. The enzyme was found to be inhibited by Al3+, Co2+, Mn2+, and Zn2+ ions while K+, Fe3+, Hg2+, and Mg2+ ions enhanced the enzyme activity; Na+ ions have no effect on enzyme activity. The purified lipase showed a variable specificity/hydrolytic activity towards various 4-nitrophenyl esters.

  7. Microbial community dynamics in thermophilic undefined milk starter cultures.

    Science.gov (United States)

    Parente, Eugenio; Guidone, Angela; Matera, Attilio; De Filippis, Francesca; Mauriello, Gianluigi; Ricciardi, Annamaria

    2016-01-18

    Model undefined thermophilic starter cultures were produced from raw milk of nine pasta-filata cheesemaking plants using a selective procedure based on pasteurization and incubation at high temperature with the objective of studying the microbial community dynamics and the variability in performances under repeated (7-13) reproduction cycles with backslopping. The traditional culture-dependent approach, based on random isolation and molecular characterization of isolates was coupled to the determination of pH and the evaluation of the ability to produce acid and fermentation metabolites. Moreover, a culture-independent approach based on amplicon-targeted next-generation sequencing was employed. The microbial diversity was evaluated by 16S rRNA gene sequencing (V1-V3 regions), while the microdiversity of Streptococcus thermophilus populations was explored by using novel approach based on sequencing of partial amplicons of the phosphoserine phosphatase gene (serB). In addition, the occurrence of bacteriophages was evaluated by qPCR and by multiplex PCR. Although it was relatively easy to select for a community dominated by thermophilic lactic acid bacteria (LAB) within a single reproduction cycle, final pH, LAB populations and acid production activity fluctuated over reproduction cycles. Both culture-dependent and -independent methods showed that the cultures were dominated by either S. thermophilus or Lactobacillus delbrueckii subsp. lactis or by both species. Nevertheless, subdominant mesophilic species, including lactococci and spoilage organisms, persisted at low levels. A limited number of serB sequence types (ST) were present in S. thermophilus populations. L. delbrueckii and Lactococcus lactis bacteriophages were below the detection limit of the method used and high titres of cos type S. thermophilus bacteriophages were detected in only two cases. In one case a high titre of bacteriophages was concurrent with a S. thermophilus biotype shift in the culture

  8. Selective fermentation of carbohydrate and protein fractions of Scenedesmus, and biohydrogenation of its lipid fraction for enhanced recovery of saturated fatty acids.

    Science.gov (United States)

    Lai, YenJung Sean; Parameswaran, Prathap; Li, Ang; Aguinaga, Alyssa; Rittmann, Bruce E

    2016-02-01

    Biofuels derived from microalgae have promise as carbon-neutral replacements for petroleum. However, difficulty extracting microalgae-derived lipids and the co-extraction of non-lipid components add major costs that detract from the benefits of microalgae-based biofuel. Selective fermentation could alleviate these problems by managing microbial degradation so that carbohydrates and proteins are hydrolyzed and fermented, but lipids remain intact. We evaluated selective fermentation of Scenedesmus biomass in batch experiments buffered at pH 5.5, 7, or 9. Carbohydrates were fermented up to 45% within the first 6 days, protein fermentation followed after about 20 days, and lipids (measured as fatty acid methyl esters, FAME) were conserved. Fermentation of the non-lipid components generated volatile fatty acids, with acetate, butyrate, and propionate being the dominant products. Selective fermentation of Scenedesmus biomass increased the amount of extractable FAME and the ratio of FAME to crude lipids. It also led to biohydrogenation of unsaturated FAME to more desirable saturated FAME (especially to C16:0 and C18:0), and the degree of saturation was inversely related to the accumulation of hydrogen gas after fermentation. Moreover, the microbial communities after selective fermentation were enriched in bacteria from families known to perform biohydrogenation, i.e., Porphyromonadaceae and Ruminococcaceae. Thus, this study provides proof-of-concept that selective fermentation can improve the quantity and quality of lipids that can be extracted from Scenedesmus. © 2015 Wiley Periodicals, Inc.

  9. A comparative study of thermophilic and mesophilic anaerobic co-digestion of food waste and wheat straw: Process stability and microbial community structure shifts.

    Science.gov (United States)

    Shi, Xuchuan; Guo, Xianglin; Zuo, Jiane; Wang, Yajiao; Zhang, Mengyu

    2018-05-01

    Renewable energy recovery from organic solid waste via anaerobic digestion is a promising way to provide sustainable energy supply and eliminate environmental pollution. However, poor efficiency and operational problems hinder its wide application of anaerobic digestion. The effects of two key parameters, i.e. temperature and substrate characteristics on process stability and microbial community structure were studied using two lab-scale anaerobic reactors under thermophilic and mesophilic conditions. Both the reactors were fed with food waste (FW) and wheat straw (WS). The organic loading rates (OLRs) were maintained at a constant level of 3 kg VS/(m 3 ·d). Five different FW:WS substrate ratios were utilized in different operational phases. The synergetic effects of co-digestion improved the stability and performance of the reactors. When FW was mono-digested, both reactors were unstable. The mesophilic reactor eventually failed due to volatile fatty acid accumulation. The thermophilic reactor had better performance compared to mesophilic one. The biogas production rate of the thermophilic reactor was 4.9-14.8% higher than that of mesophilic reactor throughout the experiment. The shifts in microbial community structures throughout the experiment in both thermophilic and mesophilic reactors were investigated. With increasing FW proportions, bacteria belonging to the phylum Thermotogae became predominant in the thermophilic reactor, while the phylum Bacteroidetes was predominant in the mesophilic reactor. The genus Methanosarcina was the predominant methanogen in the thermophilic reactor, while the genus Methanothrix remained predominant in the mesophilic reactor. The methanogenesis pathway shifted from acetoclastic to hydrogenotrophic when the mesophilic reactor experienced perturbations. Moreover, the population of lignocellulose-degrading microorganisms in the thermophilic reactor was higher than those in mesophilic reactor, which explained the better

  10. Methanogenic H2 syntrophy among thermophiles: a model of metabolism, adaptation and survival in the subsurface

    Science.gov (United States)

    Topcuoglu, B. D.; Stewart, L. C.; Butterfield, D. A.; Huber, J. A.; Holden, J. F.

    2016-12-01

    Approximately 1 giga ton (Gt, 1015 g) of CH4 is formed globally per year from H2, CO2 and acetate through methanogenesis, largely by methanogens growing in syntrophic association with anaerobic microbes that hydrolyze and ferment biopolymers. However, our understanding of methanogenesis in hydrothermal regions of the subseafloor and potential syntrophic methanogenesis at thermophilic temperatures (i.e., >50°C) is nascent. In this study, the growth of natural assemblages of thermophilic methanogens from Axial Seamount was primarily limited by H2 availability. Heterotrophs supported thermophilic methanogenesis by H2 syntrophy in microcosm incubations of hydrothermal fluids at 55°C and 80°C supplemented with tryptone only. Based on 16S rRNA gene sequencing, only heterotrophic archaea that produce H2, H2-consuming methanogens, and sulfate reducing archaea were found in 80°C tryptone microcosms from Marker 113 vent. No bacteria were found. In 55°C tryptone microcosms, sequences were found from H2-producing bacteria and H2-consuming methanogens and sulfate-reducing bacteria. In order to model the impact of H2 syntrophy at hyperthemophilic temperatures, a co-culture was established consisting of the H2-producing hyperthermophilic heterotroph Thermococcus paralvinellae and a H2-consuming hyperthermophilic methanogen Methanocaldococcus bathoardescens. When grown alone in a chemostat, the growth rates and steady-state cell concentrations of T. paralvinellae decreased significantly when a high H2 (70 µM) background was present. H2 inhibition was ameliorated by the production of formate, but in silico modeling suggests less energetic yield for the cells. H2 syntrophy relieved H2 inhibition for both the heterotroph and the methanogenic partners. The results demonstrate that thermophilic H2 syntrophy can support methanogenesis within natural microbial assemblages and may be an important alternative energy source for thermophilic autotrophs in marine geothermal environments.

  11. Experimental assessment of factors influencing dewatering properties of thermophilically digested biosolids

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jianpeng; Mavinic, Donald S.; Kelly, Harlan G.; Ramey, William D.

    2003-07-01

    Beneficial land application of processed wastewater sludges (biosolids) is a cost-effective, and environmentally sustainable option for the final disposal of sludges, because nutrients and organic matters in the sludge are recovered and reused as a resource. Thermophilic sludge digestion produces Class A biosolids, which can be reused without restrictions. Recent experience from full-scale thermophilic sludge digestion facilities in North America revealed that, dewatering thermophilically digested biosolids required more polymers to condition than mesophilically digested biosolids. This paper reports a laboratory study that investigated factors having significant impacts on dewatering properties of digested biosolids, and assessed the relationship among digestion, dewatering properties, and characteristics of thermophilically digested biosolids. The experimental work used batch-operated, bench-scale aerobic sludge digesters. Dewaterability was measured as Capillary Suction Time (CST). The study found that feed sludge composition significantly affected dewaterability of digested sludge. Higher percentage of the secondary sludge in the feed sludge corresponded to more significant deterioration in dewaterability. The effect of thermophilic digestion temperatures on dewaterabilty was rapid, occurred within 3-hour of digestion, indicting a heat shock effect, rather than a microbiological effect. When a high shear was applied to the sludge in digesters, it resulted In a significant deterioration in dewaterability in the digested sludge. It appears there was a strong correlation between dewaterability and extracellular biopolymers. Enzymes (protease) treatment confirmed that role of extracellular proteins in affecting the dewatering properties of thermophilic biosolids, also revealed the complex nature of biopolymers' effect on dewaterability. Such effects might be due to protein-polysaccharides interactions, hydrogen bonding, or hydrophilic and hydrophobic

  12. Diversity of Cultured Thermophilic Anaerobes in Hot Springs of Yunnan Province, China

    Science.gov (United States)

    Lin, L.; Lu, Y.; Dong, X.; Liu, X.; Wei, Y.; Ji, X.; Zhang, C.

    2010-12-01

    Thermophilic anaerobes including Archaea and Bacteria refer to those growing optimally at temperatures above 50°C and do not use oxygen as the terminal electron acceptor for growth. Study on thermophilic anaerobes will help to understand how life thrives under extreme conditions. Meanwhile thermophilic anaerobes are of importance in potential application and development of thermophilic biotechnology. We have surveyed culturable thermophilic anaerobes in hot springs (pH6.5-7.5; 70 - 94°C) in Rehai of Tengchong, Bangnazhang of Longlin, Eryuan of Dali,Yunnan, China. 50 strains in total were cultured from the hot springs water using Hungate anaerobic technique, and 30 strains were selected based on phenotypic diversity for analysis of 16S rDNA sequences. Phylogenetic analysis showed that 28 strains belonged to the members of five genera: Caldanaerobacter, Calaramator, Thermoanaerobacter, Dictyoglomus and Fervidobacterium, which formed five branches on the phylogenetic tree. Besides, 2 strains of methanogenic archaea were obtained. The majority of the isolates were the known species, however, seven strains were identified as novel species affiliated to the five genera based on the lower 16S rDNA sequence similarities (less than 93 - 97%) with the described species. This work would provide the future study on their diversity, distribution among different regions and the potential application of thermophilic enzyme. Supported by State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences(SKLMR-080605)and the Foundation of State Natural Science (30660009, 30960022, 31081220175).

  13. Reduction of Fe(III) oxides by phylogenetically and physiologically diverse thermophilic methanogens.

    Science.gov (United States)

    Yamada, Chihaya; Kato, Souichiro; Kimura, Satoshi; Ishii, Masaharu; Igarashi, Yasuo

    2014-09-01

    Three thermophilic methanogens (Methanothermobacter thermautotrophicus, Methanosaeta thermophila, and Methanosarcina thermophila) were investigated for their ability to reduce poorly crystalline Fe(III) oxides (ferrihydrite) and the inhibitory effects of ferrihydrite on their methanogenesis. This study demonstrated that Fe(II) generation from ferrihydrite occurs in the cultures of the three thermophilic methanogens only when H2 was supplied as the source of reducing equivalents, even in the cultures of Mst. thermophila that do not grow on and produce CH4 from H2/CO2. While supplementation of ferrihydrite resulted in complete inhibition or suppression of methanogenesis by the thermophilic methanogens, ferrihydrite reduction by the methanogens at least partially alleviates the inhibitory effects. Microscopic and crystallographic analyses on the ferrihydrite-reducing Msr. thermophila cultures exhibited generation of magnetite on its cell surfaces through partial reduction of ferrihydrite. These findings suggest that at least certain thermophilic methanogens have the ability to extracellularly transfer electrons to insoluble Fe(III) compounds, affecting their methanogenic activities, which would in turn have significant impacts on materials and energy cycles in thermophilic anoxic environments. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  14. A family 5 β-mannanase from the thermophilic fungus Thielavia arenaria XZ7 with typical thermophilic enzyme features.

    Science.gov (United States)

    Lu, Haiqiang; Zhang, Huitu; Shi, Pengjun; Luo, Huiying; Wang, Yaru; Yang, Peilong; Yao, Bin

    2013-09-01

    A novel β-mannanase gene, man5XZ7, was cloned from thermophilic fungus Thielavia arenaria XZ7, and successfully expressed in Pichia pastoris. The gene (1,110 bp) encodes a 369-amino acid polypeptide with a molecular mass of approximately 40.8 kDa. The deduced sequence of Man5XZ7 consists of a putative 17-residue signal peptide and a catalytic module belonging to glycoside hydrolase (GH) family 5, and displays 76 % identity with the experimentally verified GH 5 endo-β-1,4-mannanase from Podospora anserina. Recombinant Man5XZ7 was optimally active at 75 °C and pH 5.0 and exhibited high activity at a wide temperature range (>50.0 % activity at 50-85 °C). Moreover, it had good adaptability to acidic to basic pH (>74.1 % activity at pH 4.0-7.0 and 25.6 % even at pH 9.0) and good stability from pH 3.0 to 10.0. These enzymatic properties showed that Man5XZ7 was a new thermophilic and alkali-tolerant β-mannanase. Further amino acid composition analysis indicated that Man5XZ7 has several characteristic features of thermophilic enzymes.

  15. A strict anaerobic extreme thermophilic hydrogen-producing culture enriched from digested household waste

    DEFF Research Database (Denmark)

    Karakashev, Dimitar Borisov; Kotay, Shireen Meher; Trably, Eric

    2009-01-01

    The aim of this study was to enrich, characterize and identify strict anaerobic extreme thermophilic hydrogen (H-2) producers from digested household solid wastes. A strict anaerobic extreme thermophilic H-2 producing bacterial culture was enriched from a lab-scale digester treating household...... wastes at 70 degrees C. The enriched mixed culture consisted of two rod-shaped bacterial members growing at an optimal temperature of 80 degrees C and an optimal pH 8.1. The culture was able to utilize glucose, galactose, mannose, xylose, arabinose, maltose, sucrose, pyruvate and glycerol as carbon...... sources. Growth on glucose produced acetate, H-2 and carbon dioxide. Maximal H-2 production rate on glucose was 1.1 mmol l(-1) h(-1) with a maximum H-2 yield of 1.9 mole H-2 per mole glucose. 16S ribosomal DNA clone library analyses showed that the culture members were phylogenetically affiliated...

  16. A Combination of Stable Isotope Probing, Illumina Sequencing, and Co-occurrence Network to Investigate Thermophilic Acetate- and Lactate-Utilizing Bacteria.

    Science.gov (United States)

    Sun, Weimin; Krumins, Valdis; Dong, Yiran; Gao, Pin; Ma, Chunyan; Hu, Min; Li, Baoqin; Xia, Bingqing; He, Zijun; Xiong, Shangling

    2018-01-01

    Anaerobic digestion is a complicated microbiological process that involves a wide diversity of microorganisms. Acetate is one of the most important intermediates, and interactions between acetate-oxidizing bacteria and archaea could play an important role in the formation of methane in anoxic environments. Anaerobic digestion at thermophilic temperatures is known to increase methane production, but the effects on the microbial community are largely unknown. In the current study, stable isotope probing was used to characterize acetate- and lactate-oxidizing bacteria in thermophilic anaerobic digestion. In microcosms fed 13 C-acetate, bacteria related to members of Clostridium, Hydrogenophaga, Fervidobacterium, Spirochaeta, Limnohabitans, and Rhodococcus demonstrated elevated abundances of 13 C-DNA fractions, suggesting their activities in acetate oxidation. In the treatments fed 13 C-lactate, Anaeromyxobacter, Desulfobulbus, Syntrophus, Cystobacterineae, and Azospira were found to be the potential thermophilic lactate utilizers. PICRUSt predicted that enzymes related to nitrate and nitrite reduction would be enriched in 13 C-DNA fractions, suggesting that the acetate and lactate oxidation may be coupled with nitrate and/or nitrite reduction. Co-occurrence network analysis indicated bacterial taxa not enriched in 13 C-DNA fractions that may also play a critical role in thermophilic anaerobic digestion.

  17. Domestic sewage sludge composting in a rotary drum reactor: optimizing the thermophilic stage.

    Science.gov (United States)

    Rodríguez, Luis; Cerrillo, María I; García-Albiach, Valentín; Villaseñor, José

    2012-12-15

    The aim of this paper was to study the influence of four process variables (turning frequency, gas-phase oxygen level, type of bulking agent and sludge/bulking agent mixing ratio) on the performance of the sewage sludge composting process using a rotary drum pilot scale reactor, in order to optimize the thermophilic stage and reduce the processing time. Powdered sawdust, wood shavings, wood chips, prunings waste and straw were used as bulking agents and the thermophilic stage temperature profile was used as the main indicator for gauging if the composting process was developing correctly. Our results showed that a 12 h(-1) turning frequency and an oxygen concentration of 10% were the optimal conditions for the composting process to develop. The best results were obtained by mixing the sewage sludge with wood shavings in a 3:1 w/w ratio (on a wet basis), which adapted the initial moisture content and porosity to an optimal range and led to a maximum temperature of 70 °C being reached thus ensuring the complete removal of pathogens. Moisture, C:N ratio, pH, organic matter, heavy metals, pathogens and stability were all analysed for every mixture obtained at the end of the thermophilic stage. These parameters were compared with the limits established by the Spanish regulation on fertilizers (RD 824/2005) in order to assess if the compost obtained could be used on agricultural soils. The right combination of having optimal process variables combined with an appropriate reactor design allowed the thermophilic stage of the composting process to be speeded up, hence obtaining a compost product, after just two weeks of processing that (with the exception of the moisture content) complied with the Spanish legal requirements for fertilizers, without requiring a later maturation stage. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Comparing mesophilic and thermophilic anaerobic digestion of chicken manure: Microbial community dynamics and process resilience

    International Nuclear Information System (INIS)

    Niu, Qigui; Takemura, Yasuyuki; Kubota, Kengo; Li, Yu-You

    2015-01-01

    Highlights: • Microbial community dynamics and process functional resilience were investigated. • The threshold of TAN in mesophilic reactor was higher than the thermophilic reactor. • The recoverable archaeal community dynamic sustained the process resilience. • Methanosarcina was more sensitive than Methanoculleus on ammonia inhibition. • TAN and FA effects the dynamic of hydrolytic and acidogenic bacteria obviously. - Abstract: While methane fermentation is considered as the most successful bioenergy treatment for chicken manure, the relationship between operational performance and the dynamic transition of archaeal and bacterial communities remains poorly understood. Two continuous stirred-tank reactors were investigated under thermophilic and mesophilic conditions feeding with 10%TS. The tolerance of thermophilic reactor on total ammonia nitrogen (TAN) was found to be 8000 mg/L with free ammonia (FA) 2000 mg/L compared to 16,000 mg/L (FA1500 mg/L) of mesophilic reactor. Biomethane production was 0.29 L/gV S in in the steady stage and decreased following TAN increase. After serious inhibition, the mesophilic reactor was recovered successfully by dilution and washing stratagem compared to the unrecoverable of thermophilic reactor. The relationship between the microbial community structure, the bioreactor performance and inhibitors such as TAN, FA, and volatile fatty acid was evaluated by canonical correspondence analysis. The performance of methanogenic activity and substrate removal efficiency were changed significantly correlating with the community evenness and phylogenetic structure. The resilient archaeal community was found even after serious inhibition in both reactors. Obvious dynamics of bacterial communities were observed in acidogenic and hydrolytic functional bacteria following TAN variation in the different stages

  19. Comparing mesophilic and thermophilic anaerobic digestion of chicken manure: Microbial community dynamics and process resilience

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Qigui; Takemura, Yasuyuki; Kubota, Kengo [Department of Civil and Environmental Engineering, Graduate School of Engineering Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Li, Yu-You, E-mail: yyli@epl1.civil.tohoku.ac.jp [Department of Civil and Environmental Engineering, Graduate School of Engineering Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi’an University of Architecture and Technology, Xi’an (China)

    2015-09-15

    Highlights: • Microbial community dynamics and process functional resilience were investigated. • The threshold of TAN in mesophilic reactor was higher than the thermophilic reactor. • The recoverable archaeal community dynamic sustained the process resilience. • Methanosarcina was more sensitive than Methanoculleus on ammonia inhibition. • TAN and FA effects the dynamic of hydrolytic and acidogenic bacteria obviously. - Abstract: While methane fermentation is considered as the most successful bioenergy treatment for chicken manure, the relationship between operational performance and the dynamic transition of archaeal and bacterial communities remains poorly understood. Two continuous stirred-tank reactors were investigated under thermophilic and mesophilic conditions feeding with 10%TS. The tolerance of thermophilic reactor on total ammonia nitrogen (TAN) was found to be 8000 mg/L with free ammonia (FA) 2000 mg/L compared to 16,000 mg/L (FA1500 mg/L) of mesophilic reactor. Biomethane production was 0.29 L/gV S{sub in} in the steady stage and decreased following TAN increase. After serious inhibition, the mesophilic reactor was recovered successfully by dilution and washing stratagem compared to the unrecoverable of thermophilic reactor. The relationship between the microbial community structure, the bioreactor performance and inhibitors such as TAN, FA, and volatile fatty acid was evaluated by canonical correspondence analysis. The performance of methanogenic activity and substrate removal efficiency were changed significantly correlating with the community evenness and phylogenetic structure. The resilient archaeal community was found even after serious inhibition in both reactors. Obvious dynamics of bacterial communities were observed in acidogenic and hydrolytic functional bacteria following TAN variation in the different stages.

  20. Improved methane production from sugarcane vinasse with filter cake in thermophilic UASB reactors, with predominance of Methanothermobacter and Methanosarcina archaea and Thermotogae bacteria.

    Science.gov (United States)

    Barros, Valciney Gomes de; Duda, Rose Maria; Vantini, Juliana da Silva; Omori, Wellington Pine; Ferro, Maria Inês Tiraboschi; Oliveira, Roberto Alves de

    2017-11-01

    Biogas production from sugarcane vinasse has enormous economic, energy, and environmental management potential. However, methane production stability and biodigested vinasse quality remain key issues, requiring better nutrient and alkalinity availability, operational strategies, and knowledge of reactor microbiota. This study demonstrates increased methane production from vinasse through the use of sugarcane filter cake and improved effluent recirculation, with elevated organic loading rates (OLR) and good reactor stability. We used UASB reactors in a two-stage configuration, with OLRs up to 45gCODL -1 d -1 , and obtained methane production as high as 3LL -1 d -1 . Quantitative PCR indicated balanced amounts of bacteria and archaea in the sludge (10 9 -10 10 copiesg -1 VS), and of the predominant archaea orders, Methanobacteriales and Methanosarcinales (10 6 -10 8 copiesg -1 VS). 16S rDNA sequencing also indicated the thermophilic Thermotogae as the most abundant class of bacteria in the sludge. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. The genotypic diversity and lipase production of some thermophilic bacilli from different genera

    Directory of Open Access Journals (Sweden)

    Melih Koc

    2015-12-01

    Full Text Available Abstract Thermophilic 32 isolates and 20 reference bacilli were subjected to Rep-PCR and ITS-PCR fingerprinting for determination of their genotypic diversity, before screening lipase activities. By these methods, all the isolates and references could easily be differentiated up to subspecies level from each other. In screening assay, 11 isolates and 7 references were found to be lipase producing. Their extracellular lipase activities were measured quantitatively by incubating in both tributyrin and olive oil broths at 60 °C and pH 7.0. During the 24, 48 and 72-h period of incubation, the changes in the lipase activities, culture absorbance, wet weight of biomass and pH were all measured. The activity was determined by using pNPB in 50 mM phosphate buffer at pH 7.0 at 60 °C. The lipase production of the isolates in olive oil broths varied between 0.008 and 0.052, whereas these values were found to be 0.002-0.019 (U/mL in the case of tyributyrin. For comparison, an index was established by dividing the lipase activities to cell biomass (U/mg. The maximum thermostable lipase production was achieved by the isolates F84a, F84b, and G. thermodenitrificans DSM 465T (0.009, 0.008 and 0.008 U/mg within olive oil broth, whereas G. stearothermophilus A113 displayed the highest lipase activity than its type strain in tyributyrin. Therefore, as some of these isolates displayed higher activities in comparison to references, new lipase producing bacilli were determined by presenting their genotypic diversity with DNA fingerprinting techniques.

  2. Mesophilic and thermophilic activated sludge post-treatment of paper mill process water

    NARCIS (Netherlands)

    Vogelaar, J.C.T.; Bouwhuis, E.; Klapwijk, A.; Spanjers, H.; Lier, van J.B.

    2002-01-01

    Increasing system closure in paper mills and higher process water temperatures make the applicability of thermophilic treatment systems increasingly important. The use of activated sludge as a suitable thermophilic post-treatment system for anaerobically pre-treated paper process water from a paper

  3. Recombinant HAP Phytase of the Thermophilic Mold Sporotrichum thermophile: Expression of the Codon-Optimized Phytase Gene in Pichia pastoris and Applications.

    Science.gov (United States)

    Ranjan, Bibhuti; Satyanarayana, T

    2016-02-01

    The codon-optimized phytase gene of the thermophilic mold Sporotrichum thermophile (St-Phy) was expressed in Pichia pastoris. The recombinant P. pastoris harboring the phytase gene (rSt-Phy) yielded a high titer of extracellular phytase (480 ± 23 U/mL) on induction with methanol. The recombinant phytase production was ~40-fold higher than that of the native fungal strain. The purified recombinant phytase (rSt-Phy) has the molecular mass of 70 kDa on SDS-PAGE, with K m and V max (calcium phytate), k cat and k cat/K m values of 0.147 mM and 183 nmol/mg s, 1.3 × 10(3)/s and 8.84 × 10(6)/M s, respectively. Mg(2+) and Ba(2+) display a slight stimulatory effect, while other cations tested exert inhibitory action on phytase. The enzyme is inhibited by chaotropic agents (guanidinium hydrochloride, potassium iodide, and urea), Woodward's reagent K and 2,3-bunatedione, but resistant to both pepsin and trypsin. The rSt-Phy is useful in the dephytinization of broiler feeds efficiently in simulated gut conditions of chick leading to the liberation of soluble inorganic phosphate with concomitant mitigation in antinutrient effects of phytates. The addition of vanadate makes it a potential candidate for generating haloperoxidase, which has several applications.

  4. Biorefineries for chemical and biofuel production

    DEFF Research Database (Denmark)

    Fjerbæk Søtoft, Lene

    crops for biofuel production is research in biorefineries using a whole-crop approach with the aim of having an optimal use of all the components of the specific crop. Looking at rape as a model crop, the components can be used for i.e. bioethanol, biodiesel, biogas, biohydrogen, feed, food and plant...

  5. Conversion of hemicelluloses and D-xylose into ethanol by the use of thermophilic anaerobic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-05-01

    Ethanol is a CO{sub 2} neutral liquid fuel that can substitute the use of fossil fuels in the transportation sector, thereby reducing the CO{sub 2} emission to the atmosphere. CO{sub 2} emission is suspected to contribute significantly to the so-called greenhouse effect, the global heating. Substrates for production of ethanol must be cheap and plentiful. This can be met by the use of lignocellulosic biomass such as willow, wheat straw, hardwood and softwood. However, the complexity of these polymeric substrates and the presence of several types of carbohydrates (glucose, xylose, mannose, galactose, arabinose) require additional treatment to release the useful carbohydrates and ferment the major carbohydrates fractions. The costs related to the ethanol-production must be kept at a minimum to be price competitive compared to gasoline. Therefore all of the carbohydrates present in lignocellulose need to be converted into ethanol. Glucose can be fermented to ethanol by yeast strains such as Saccharomyces cerevisiae, which, however, is unable to ferment the other major carbohydrate fraction, D-xylose. Thermophilic anaerobic ethanol producing bacteria can be used for fermentation of the hemicelluloses fraction of lignocellulosic biomass. However, physiological studies of thermophilic anaerobic bacteria have shown that the ethanol yield decreases at increasing substrate concentration. The biochemical limitations causing this phenomenon are not known in detail. Physiological and biochemical studies of a newly characterized thermophilic anaerobic ethanol producing bacterium, Thermoanaerobacter mathranii, was performed. This study included extraction of intracellular metabolites and enzymes of the pentose phosphate pathway and glycolysis. These studies revealed several bottlenecks in the D-xylose metabolism. This knowledge makes way for physiological and genetic engineering of this strain to improve the ethanol yield and productivity at high concentration of D-xylose. (au)

  6. Isolation and characterization of two novel ethanol-tolerant facultative-anaerobic thermophilic bacteria strains from waste compost.

    Science.gov (United States)

    Fong, Jiunn C N; Svenson, Charles J; Nakasugi, Kenlee; Leong, Caine T C; Bowman, John P; Chen, Betty; Glenn, Dianne R; Neilan, Brett A; Rogers, Peter L

    2006-10-01

    In a search for potential ethanologens, waste compost was screened for ethanol-tolerant thermophilic microorganisms. Two thermophilic bacterial strains, M5EXG and M10EXG, with tolerance of 5 and 10% (v/v) ethanol, respectively, were isolated. Both isolates are facultative anaerobic, non-spore forming, non-motile, catalase-positive, oxidase-negative, Gram-negative rods that are capable of utilizing a range of carbon sources including arabinose, galactose, mannose, glucose and xylose and produce low amounts of ethanol, acetate and lactate. Growth of both isolates was observed in fully defined minimal media within the temperature range 50-80 degrees C and pH 6.0-8.0. Phylogenetic analysis of the 16S rDNA sequences revealed that both isolates clustered with members of subgroup 5 of the genus Bacillus. G+C contents and DNA-DNA relatedness of M5EXG and M10EXG revealed that they are strains belonging to Geobacillus thermoglucosidasius. However, physiological and biochemical differences were evident when isolates M5EXG and M10EXG were compared with G. thermoglucosidasius type strain (DSM 2542(T)). The new thermophilic, ethanol-tolerant strains of G. thermoglucosidasius may be candidates for ethanol production at elevated temperatures.

  7. Efficient Genome Editing of a Facultative Thermophile Using Mesophilic spCas9

    NARCIS (Netherlands)

    Mougiakos, Ioannis; Bosma, Elleke F.; Weenink, Koen; Vossen, Eric; Goijvaerts, Kirsten; Oost, van der John; Kranenburg, van Richard

    2017-01-01

    Well-developed genetic tools for thermophilic microorganisms are scarce, despite their industrial and scientific relevance. Whereas highly efficient CRISPR/Cas9-based genome editing is on the rise in prokaryotes, it has never been employed in a thermophile. Here, we apply Streptococcus pyogenes

  8. Biological Hydrogen Production from Corn-Syrup Waste Using a Novel System

    Directory of Open Access Journals (Sweden)

    George Nakhla

    2009-06-01

    Full Text Available The reported patent-pending system comprises a novel biohydrogen reactor with a gravity settler for decoupling of SRT from HRT. The biohydrogenator was operated for 100 days at 37 °C, hydraulic retention time 8 h and solids retention time ranging from 2.2–2.5 days. The feed was a corn-syrup waste generated as a byproduct from an industrial facility for bioethanol production located in southwestern Ontario, Canada. The system was initially started up with a synthetic feed containing glucose at concentration of 8 g/L and other essential inorganics. Anaerobicaly-digested sludge from the St. Mary’s wastewater treatment plant (St. Mary, Ontario, Canada was used as the seed, and was heat treated at 70 °C for 30 min to inhibit methanogens. After 10 days, when the hydrogen production was steady, the corn-syrup waste was introduced to the system. Glucose was the main constituent in the corn-syrup; its concentration was varied over a period of 90 days from 8 to 25 g/L. The change in glucose concentration was used to study the impact of variable organic loading on the stability of hydrogen production in the biohydrogenator. Hydrogen production rate increased from 10 L H2/L·d to 34 L H2/L·d with the increase of organic loading rate (OLR from 26 to 81 gCOD/L·d, while a maximum hydrogen yield of 430 mL H2/gCOD was achieved in the system with an overall average of 385 mL H2/gCOD.

  9. Enrichment of Thermophilic Propionate-Oxidizing Bacteria in Syntrophy with Methanobacterium thermoautotrophicum or Methanobacterium thermoformicicum

    OpenAIRE

    Stams, Alfons J. M.; Grolle, Katja C. F.; Frijters, Carla T. M.; Van Lier, Jules B.

    1992-01-01

    Thermophilic propionate-oxidizing, proton-reducing bacteria were enriched from the granular methanogenic sludge of a bench-scale upflow anaerobic sludge bed reactor operated at 55°C with a mixture of volatile fatty acids as feed. Thermophilic hydrogenotrophic methanogens had a high decay rate. Therefore, stable, thermophilic propionate-oxidizing cultures could not be obtained by using the usual enrichment procedures. Stable and reproducible cultivation was possible by enrichment in hydrogen-p...

  10. Dewaterability of thermophilically digested biosolids: effects of temperature and cellular polymeric substances

    International Nuclear Information System (INIS)

    Zhou, J.; Mavinic, D.S.; Kelly, H.G.; Ramey, W.D.

    2002-01-01

    Thermophilic processes digest sludge at high temperatures to produce Class A biosolids.Recent research work revealed that digestion temperature is the predominant factor affecting dewaterability of thermophilic biosolids. This paper presents findings of a laboratory study that investigated how various digestion temperatures affect dewaterability of digested biosolids, studied the phase partition of the substances affecting dewaterability in digested biosolids, and tested the role of cellular polymeric substances in affecting dewaterability.Secondary sludges were digested at 40-70 o C or 22 o C for up to 12 days. Centrate from thermophilically digested biosolids were treated with protease and boiling. This study found that, during the first few hours of digestion, higher temperatures resulted in more rapid and more significant deterioration in dewaterability than lower digestion temperatures. Continued digestion resulted in either improved (60 o C or 70 o C), or unchanged (40 o C or 50 o C), or gradually deteriorated dewaterability (22 o C). The substances affecting dewaterability were primarily located in the liquid phase of thermophilically digested biosolids. Boiling treatment did not result in significant changes in dewaterability. Protease treatment of the liquid phase of thermophilic biosolids improved dewaterability by 13-19%. Such an improvement confirmed the role of proteins in affecting dewaterability. (author)

  11. Anaerobic thermophilic culture-system

    Energy Technology Data Exchange (ETDEWEB)

    Ljungdahl, L G; Wiegel, J K.W.

    1981-04-14

    A mixed culture system of Thermoanaerobacter ethanolicus and Clostridium thermocellum is employed for anaerobic, thermophilic ethanol fermentation of cellulose. By cellulase action, monosaccharides are formed which inhibit the growth of C. thermocellum, but are fermented by T. ethanolicus. Thus, at a regulated pH-value of 7.5, this mixed culture system of micro organisms results in a cellulose fermentation with a considerably higher ethanol yield.

  12. Establishment and Characterization of an Anaerobic Thermophilic (55 degrees C) Enrichment Culture Degrading Long-Chain Fatty Acids

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Ahring, Birgitte Kiær

    1995-01-01

    A thermophilic, long-chain fatty acid-oxidizing culture was enriched. Stearate was used as the substrate, and methane and carbon dioxide were the sole end products. Cultivation was possible only when a fed-batch system was used or with addition of activated carbon or bentonite. The enrichment...

  13. Thermophilic anaerobic digestion of Lurgi coal gasification wastewater in a UASB reactor

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.; Ma, W.C.; Han, H.J.; Li, H.Q.; Yuan, M. [Harbin Institute of Technology, Harbin (China)

    2011-02-15

    Lurgi coal gasification wastewater (LCGW) is a refractory wastewater, whose anaerobic treatment has been a severe problem due to its toxicity and poor biodegradability. Using a mesophilic (35 {+-} 2{sup o}C) reactor as a control, thermophilic anaerobic digestion (55 {+-} 2{sup o}C) of LCGW was investigated in a UASB reactor. After 120 days of operation, the removal of COD and total phenols by the thermophilic reactor could reach 50-55% and 50-60% respectively, at an organic loading rate of 2.5 kg COD/(m{sup 3} d) and HRT of 24h: the corresponding efficiencies were both only 20-30% in the mesophilic reactor. After thermophilic digestion, the wastewater concentrations of the aerobic effluent COD could reach below 200 mg/L compared with around 294 mg/L if mesophilic digestion was done and around 375 mg/L if sole aerobic pre-treatment was done. The results suggested that thermophilic anaerobic digestion improved significantly both anaerobic and aerobic biodegradation of LCGW.

  14. Continuous production of biohythane from hydrothermal liquefied cornstalk biomass via two-stage high-rate anaerobic reactors.

    Science.gov (United States)

    Si, Bu-Chun; Li, Jia-Ming; Zhu, Zhang-Bing; Zhang, Yuan-Hui; Lu, Jian-Wen; Shen, Rui-Xia; Zhang, Chong; Xing, Xin-Hui; Liu, Zhidan

    2016-01-01

    Biohythane production via two-stage fermentation is a promising direction for sustainable energy recovery from lignocellulosic biomass. However, the utilization of lignocellulosic biomass suffers from specific natural recalcitrance. Hydrothermal liquefaction (HTL) is an emerging technology for the liquefaction of biomass, but there are still several challenges for the coupling of HTL and two-stage fermentation. One particular challenge is the limited efficiency of fermentation reactors at a high solid content of the treated feedstock. Another is the conversion of potential inhibitors during fermentation. Here, we report a novel strategy for the continuous production of biohythane from cornstalk through the integration of HTL and two-stage fermentation. Cornstalk was converted to solid and liquid via HTL, and the resulting liquid could be subsequently fed into the two-stage fermentation systems. The systems consisted of two typical high-rate reactors: an upflow anaerobic sludge blanket (UASB) and a packed bed reactor (PBR). The liquid could be efficiently converted into biohythane via the UASB and PBR with a high density of microbes at a high organic loading rate. Biohydrogen production decreased from 2.34 L/L/day in UASB (1.01 L/L/day in PBR) to 0 L/L/day as the organic loading rate (OLR) of the HTL liquid products increased to 16 g/L/day. The methane production rate achieved a value of 2.53 (UASB) and 2.54 L/L/day (PBR), respectively. The energy and carbon recovery of the integrated HTL and biohythane fermentation system reached up to 79.0 and 67.7%, respectively. The fermentation inhibitors, i.e., 5-hydroxymethyl furfural (41.4-41.9% of the initial quantity detected) and furfural (74.7-85.0% of the initial quantity detected), were degraded during hydrogen fermentation. Compared with single-stage fermentation, the methane process during two-stage fermentation had a more efficient methane production rate, acetogenesis, and COD removal. The microbial distribution

  15. High ethanol tolerance of the thermophilic anaerobic ethanol producer Thermoanaerobacter BG1L1

    DEFF Research Database (Denmark)

    Georgieva, Tania I.; Mikkelsen, Marie Just; Ahring, Birgitte Kiær

    2007-01-01

    The low ethanol tolerance of thermophilic anaerobic bacteria, generally less than 2% (v/v) ethanol, is one of the main limiting factors for their potential use for second generation fuel ethanol production. In this work, the tolerance of thermophilic anaerobic bacterium Thermoanaerobacter BG 1L1...... to exogenously added ethanol was studied in a continuous immobilized reactor system at a growth temperature of 70 degrees C. Ethanol tolerance was evaluated based on inhibition of fermentative performance e.g.. inhibition of substrate conversion. At the highest ethanol concentration tested (8.3% v/v), the strain...... was able to convert 42% of the xylose initially present, indicating that this ethanol concentration is not the upper limit tolerated by the strain. Long-term strain adaptation to high ethanol concentrations (6 - 8.3%) resulted in an improvement of xylose conversion by 25% at an ethanol concentration of 5...

  16. Thermoascus aurantiacus is a promising source of enzymes for biomass deconstruction under thermophilic conditions

    Directory of Open Access Journals (Sweden)

    McClendon Shara D

    2012-07-01

    biomass deconstruction, without strain development or genetic modifications. Therefore, T. aurantiacus provides an excellent platform to develop a thermophilic fungal system for enzyme production for the conversion of biomass to biofuels.

  17. Thermoascus aurantiacus is a promising source of enzymes for biomass deconstruction under thermophilic conditions.

    Science.gov (United States)

    McClendon, Shara D; Batth, Tanveer; Petzold, Christopher J; Adams, Paul D; Simmons, Blake A; Singer, Steven W

    2012-07-28

    genetic modifications. Therefore, T. aurantiacus provides an excellent platform to develop a thermophilic fungal system for enzyme production for the conversion of biomass to biofuels.

  18. Enzyme activity screening of thermophilic bacteria isolated from Dusun Tua Hot Spring, Malaysia

    Science.gov (United States)

    Msarah, Marwan; Ibrahim, Izyanti; Aqma, Wan Syaidatul

    2018-04-01

    Thermophilic bacteria have biotechnological importance due to the availability of unique enzymes which are stable in extreme circumstances. The aim of this study includes to isolate thermophilic bacteria from hot spring and screen for important enzyme activities. Water samples from the Dusun Tua Hot Spring were collected and the physiochemical characterisation of water was measured. Eight thermophilic bacteria were isolated and determined to have at least three strong enzyme activity including protease, lipase, amylase, cellulase, pectinase and xylanase. The results showed that HuluC2 displayed all the enzyme activities and can be further studied.

  19. Bacterial community analysis of swine manure treated with autothermal thermophilic aerobic digestion.

    Science.gov (United States)

    Han, Il; Congeevaram, Shankar; Ki, Dong-Won; Oh, Byoung-Taek; Park, Joonhong

    2011-02-01

    Due to the environmental problems associated with disposal of livestock sludge, many stabilization studies emphasizing on the sludge volume reduction were performed. However, little is known about the microbial risk present in sludge and its stabilized products. This study microbiologically explored the effects of anaerobic lagoon fermentation (ALF) and autothermal thermophilic aerobic digestion (ATAD) on pathogen-related risk of raw swine manure by using culture-independent 16S rDNA cloning and sequencing methods. In raw swine manure, clones closely related to pathogens such as Dialister pneumosintes, Erysipelothrix rhusiopathiae, Succinivibrioan dextrinosolvens, and Schineria sp. were detected. Meanwhile, in the mesophilic ALF-treated swine manure, bacterial community clones closely related to pathogens such as Schineria sp. and Succinivibrio dextrinosolvens were still detected. Interestingly, the ATAD treatment resulted in no detection of clones closely related to pathogens in the stabilized thermophilic bacterial community, with the predominance of novel Clostridia class populations. These findings support the superiority of ATAD in selectively reducing potential human and animal pathogens compared to ALF, which is a typical manure stabilization method used in livestock farms.

  20. Thermophilic composting of municipal solid waste

    International Nuclear Information System (INIS)

    Elango, D.; Thinakaran, N.; Panneerselvam, P.; Sivanesan, S.

    2009-01-01

    Process of composting has been developed for recycling of organic fraction of municipal solid waste (MSW). The bioreactor design was modified to reduce the composting process time. The main goal of this investigation was to find the optimal value of time period for composting of MSW in thermophilic bioreactor under aerobic condition. The temperature profiles correlated well with experimental data obtained during the maturation process. During this period biological degraders are introduced in to the reactor to accelerate the composting process. The compost materials were analyzed at various stages and the environmental parameters were considered. The final composting materials contained large organic content with in a short duration of 40 days. The quantity of volume reduction of raw MSW was 78%. The test result shows that the final compost material from the thermophilic reactor provides good humus to build up soil characteristics and some basic plant nutrients

  1. Recent developments in the thermophilic microbiology of deep-sea hydrothermal vents.

    Science.gov (United States)

    Miroshnichenko, Margarita L; Bonch-Osmolovskaya, Elizaveta A

    2006-04-01

    The diversity of thermophilic prokaryotes inhabiting deep-sea hot vents was actively studied over the last two decades. The ever growing interest is reflected in the exponentially increasing number of novel thermophilic genera described. The goal of this paper is to survey the progress in this field made in the years 2000-2005. In this period, representatives of several new taxa of hyperthermophilic archaea were obtained from deep-sea environments. Two of these isolates had phenotypic features new for this group of organisms: the presence of an outer cell membrane (the genus Ignicoccus) and the ability to grow anaerobically with acetate and ferric iron (the genus Geoglobus). Also, our knowledge on the diversity of thermophilic bacteria from deep-sea thermal environments extended significantly. The new bacterial isolates represented diverse bacterial divisions: the phylum Aquificae, the subclass Epsilonproteobacteria, the order Thermotogales, the families Thermodesulfobacteriaceae, Deferribacteraceae, and Thermaceae, and a novel bacterial phylum represented by the genus Caldithrix. Most of these isolates are obligate or facultative lithotrophs, oxidizing molecular hydrogen in the course of different types of anaerobic respiration or microaerobic growth. The existence and significant ecological role of some of new bacterial thermophilic isolates was initially established by molecular methods.

  2. Inactivation of Clostridium difficile in sewage sludge by anaerobic thermophilic digestion.

    Science.gov (United States)

    Xu, Changyun; Salsali, Hamidreza; Weese, Scott; Warriner, Keith

    2016-01-01

    There has been an increase in community-associated Clostridium difficile infections with biosolids derived from wastewater treatment being identified as one potential source. The current study evaluated the efficacy of thermophilic digestion in decreasing levels of C. difficile ribotype 078 associated with sewage sludge. Five isolates of C. difficile 078 were introduced (final density of 5 log CFU/g) into digested sludge and subjected to anaerobic digestion at mesophilic (36 or 42 °C) or thermophilic (55 °C) temperatures for up to 60 days. It was found that mesophilic digestion at 36 °C did not result in a significant reduction in C. difficile spore levels. In contrast, thermophilic sludge digestion reduced endospore levels at a rate of 0.19-2.68 log CFU/day, depending on the strain tested. The mechanism of lethality was indirect - by stimulating germination then inactivating the resultant vegetative cells. Acidification of sludge by adding acetic acid (6 g/L) inhibited the germination of spores regardless of the sludge digestion temperature. In conclusion, thermophilic digestion can be applied to reduce C. difficile in biosolids, thereby reducing the environmental burden of the enteric pathogen.

  3. Microbial electrohydrogenesis linked to dark fermentation as integrated application for enhanced biohydrogen production: A review on process characteristics, experiences and lessons.

    Science.gov (United States)

    Bakonyi, Péter; Kumar, Gopalakrishnan; Koók, László; Tóth, Gábor; Rózsenberszki, Tamás; Bélafi-Bakó, Katalin; Nemestóthy, Nándor

    2018-03-01

    Microbial electrohydrogenesis cells (MECs) are devices that have attracted significant attention from the scientific community to generate hydrogen gas electrochemically with the aid of exoelectrogen microorganisms. It has been demonstrated that MECs are capable to deal with the residual organic materials present in effluents generated along with dark fermentative hydrogen bioproduction (DF). Consequently, MECs stand as attractive post-treatment units to enhance the global H 2 yield as a part of a two-stage, integrated application (DF-MEC). In this review article, it is aimed (i) to assess results communicated in the relevant literature on cascade DF-MEC systems, (ii) describe the characteristics of each steps involved and (iii) discuss the experiences as well as the lessons in order to facilitate knowledge transfer and help the interested readers with the construction of more efficient coupled set-ups, leading eventually to the improvement of overall biohydrogen evolution performances. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Effects of seed sludge on fermentative characteristics and microbial community structures in thermophilic hydrogen fermentation of starch

    Energy Technology Data Exchange (ETDEWEB)

    Akutsu, Yohei; Tandukar, Madan; Kubota, Kengo; Harada, Hideki [Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Sendai, Miyagi 980-8579 (Japan); Li, Yu-You [Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Sendai, Miyagi 980-8579 (Japan); Department of Urban and Environmental Engineering, Tianjin Institute of Urban Construction, Jinjinggonglu 26, Tianjin, 300384 (China)

    2008-11-15

    In this work, effects of seed sludge on thermophilic hydrogen fermentation were investigated. Five different kinds of sludge were separately inoculated in completely stirred tank reactors (CSTRs), without any pretreatment. The reactors were operated in parallel with starch as substrate under thermophilic condition (55 C) at a hydraulic retention time (HRT) of 24 h for 50 days. Stable hydrogen production was achieved in all reactors. The highest hydrogen yield (2.32 mol H{sub 2}/mol glucose) was obtained from the reactor seeded with thermophilically digested activated sludge. The stoichiometric equation of hydrogen fermentation calculated using the data obtained in this study was expressed as follows: starch ([C{sub 6}H{sub 10}O{sub 5}]n) {yields} 2.32n H{sub 2} + 2.14n CO{sub 2} + 0.50n acetate + 0.63n butyrate + 0.11n cell (C{sub 5}H{sub 7}NO{sub 2}). Microbial community structure was analyzed by polymerase chain reaction-denaturing gel gradient electrophoresis (PCR-DGGE) and 16S rRNA gene cloning. Close relatives of the Thermoanaerobacterium were found to be the most predominated one in all reactors. (author)

  5. Characterisation of community structure of bacteria in parallel mesophilic and thermophilic pilot scale anaerobe sludge digesters.

    Science.gov (United States)

    Tauber, T; Berta, Brigitta; Székely, Anna J; Gyarmati, I; Kékesi, Katalin; Márialigeti, K; Tóth, Erika M

    2007-03-01

    The aim of the present work was to compare the microbial communities of a mesophilic and a thermophilic pilot scale anaerobe sludge digester. For studying the communities cultivation independent chemotaxonomical methods (RQ and PLFA analyses) and T-RFLP were applied. Microbial communities of the mesophilic and thermophilic pilot digesters showed considerable differences, both concerning the species present, and their abundance. A Methanosarcina sp. dominated the thermophilic, while a Methanosaeta sp. the mesophilic digester among Archaea. Species diversity of Bacteria was reduced in the thermophilic digester. Based on the quinone patterns in both digesters the dominance of sulphate reducing respiratory bacteria could be detected. The PLFA profiles of the digester communities were similar though in minor components characteristic differences were shown. Level of branched chain fatty acids is slightly lower in the thermophilic digester that reports less Gram positive bacteria. The relative ratio of fatty acids characteristic to Enterobacteriaceae, Bacteroidetes and Clostridia shows differences between the two digesters: their importance generally decreased under thermophilic conditions. The sulphate reducer marker (15:1 and 17:1) fatty acids are present in low quantity in both digesters.

  6. Supplement to thermophilic hydrolysis of liquid manures. Bilag til termofil hydrolyse af gylle

    Energy Technology Data Exchange (ETDEWEB)

    1990-07-01

    A supplement to ''Thermophilic hydrolysis of liquid manures'' which contains descriptions of testing methods and results for determining the influence of additives such as propionic acid or triolein on chemical reactions in connection with the decomposition of liquid manures under thermophilic conditions. (AB).

  7. Prospecting Agro-waste Cocktail: Supplementation for Cellulase Production by a Newly Isolated Thermophilic B. licheniformis 2D55.

    Science.gov (United States)

    Kazeem, Muinat Olanike; Shah, Umi Kalsom Md; Baharuddin, Azhari Samsu; AbdulRahman, Nor' Aini

    2017-08-01

    Bacteria isolated from thermophilic environment that can produce cellulase as well as utilise agro-waste biomass have a high potential for developing thermostable cellulase required in the biofuel industry. The cost for cellulase represents a significant challenge in converting lignocellulose to fermentable sugars for biofuel production. Among three potential bacteria examined, Bacillus licheniformis 2D55 (accession no. KT799651) was found to produce the highest cellulolytic activity (CMCase 0.33 U/mL and FPase 0.09 U/mL) at 18-24 h fermentation when grown on microcrystalline cellulose (MCC) as a carbon source in shake flask at 50 °C. Cellulase production process was further conducted on the untreated and NaOH pretreated rice straw (RS), rice husk (RH), sugarcane bagasse (BAG) and empty fruit bunch (EFB). Untreated BAG produced the highest FPase (0.160 U/mL), while the highest CMCase (0.150 U/mL) was supported on the pretreated RH. The mixture of untreated BAG and pretreated RH as agro-waste cocktail has remarkably improved CMCase (3.7- and 1.4-fold) and FPase (2.5- and 11.5-fold) compared to the untreated BAG and pretreated RH, respectively. The mechanism of cellulase production explored through SEM analysis and the location of cellulase enzymes of the isolate was also presented. Agro-waste cocktail supplementation provides an alternative method for an efficient production of cellulase.

  8. Characterization of microbial compositions in a thermophilic chemostat of mixed culture fermentation.

    Science.gov (United States)

    Zhang, Fang; Yang, Jing-Hua; Dai, Kun; Chen, Yun; Li, Qiu-Rong; Gao, Fa-Ming; Zeng, Raymond J

    2016-02-01

    The microbial community compositions of a chemostat enriched in a thermophilic (55 °C) mixed culture fermentation (MCF) for hydrogen production under different operational conditions were revealed in this work by integrating denaturing gradient gel electrophoresis (DGGE), Illumina Miseq high-throughput sequencing, and 16S rRNA clone library sequencing. The results showed that the community structure of the enriched cultures was relatively simple. Clones close to the genera of Thermoanaerobacter and/or Bacillus mainly dominated the bacteria. And homoacetogens and archaea were washed out and not detected even by Illumina Miseq high-throughput sequencing which supported the benefit for hydrogen production. On the other hand, the results revealed that the metabolic shift was clearly associated with the change of dominated bacterial groups. The effects of hydrogen partial pressure (PH2) and pH from 4.0 to 5.5 on the microbial compositions were not notable and Thermoanaerobacter was dominant, thus, the metabolites were also not changed. While Bacillus, Thermoanaerobacter and Propionispora hippei dominated the bacteria communities at neutral pH, or Bacillus and Thermoanaerobacter dominated at high influent glucose concentrations, consequently the main metabolites shifted to acetate, ethanol, propionate, or lactate. Thereby, the effect of microbial composition on the metabolite distribution and shift shall be considered when modeling thermophilic MCF in the future.

  9. An integrated system for hydrogen and methane production during landfill leachate treatment

    Energy Technology Data Exchange (ETDEWEB)

    Hafez, Hisham; Nakhla, George; El Naggar, Hesham [Civil and Environmental Engineering Department, University of Western Ontario, London, Ontario (Canada)

    2010-05-15

    The patent-pending integrated waste-to-energy system comprises both a novel biohydrogen reactor with a gravity settler (Biohydrogenator), followed by a second stage conventional anaerobic digester for the production of methane gas. This chemical-free process has been tested with a synthetic wastewater/leachate solution, and was operated at 37 C for 45 d. The biohydrogenator (system (A), stage 1) steadily produced hydrogen with no methane during the experimental period. The maximum hydrogen yield was 400 mL H{sub 2}/g glucose with an average of 345 mL H{sub 2}/g glucose, as compared to 141 and 118 mL H{sub 2}/g glucose for two consecutive runs done in parallel using a conventional continuously stirred tank reactor (CSTR, System (B)). Decoupling of the solids retention time (SRT) from the hydraulic retention time (HRT) using the gravity settler showed a marked improvement in performance, with the maximum and average hydrogen production rates in system (A) of 22 and 19 L H{sub 2}/d, as compared with 2-7 L H{sub 2}/d in the CSTR resulting in a maximum yield of 2.8 mol H{sub 2}/mol glucose much higher than the 1.1-1.3 mol H{sub 2}/mol glucose observed in the CSTR. Furthermore, while the CSTR collapsed in 10-15 d due to biomass washout, the biohydrogenator continued stable operation for the 45 d reported here and beyond. The methane yield for the second stage in system (A) approached a maximum value of 426 mL CH{sub 4}/gCOD removed, while an overall chemical oxygen demand (COD) removal efficiency of 94% was achieved in system (A). (author)

  10. Stable acetate production in extreme-thermophilic (70°C) mixed culture fermentation by selective enrichment of hydrogenotrophic methanogens

    Science.gov (United States)

    Zhang, Fang; Zhang, Yan; Ding, Jing; Dai, Kun; van Loosdrecht, Mark C. M.; Zeng, Raymond J.

    2014-06-01

    The control of metabolite production is difficult in mixed culture fermentation. This is particularly related to hydrogen inhibition. In this work, hydrogenotrophic methanogens were selectively enriched to reduce the hydrogen partial pressure and to realize efficient acetate production in extreme-thermophilic (70°C) mixed culture fermentation. The continuous stirred tank reactor (CSTR) was stable operated during 100 days, in which acetate accounted for more than 90% of metabolites in liquid solutions. The yields of acetate, methane and biomass in CSTR were 1.5 +/- 0.06, 1.0 +/- 0.13 and 0.4 +/- 0.05 mol/mol glucose, respectively, close to the theoretical expected values. The CSTR effluent was stable and no further conversion occurred when incubated for 14 days in a batch reactor. In fed-batch experiments, acetate could be produced up to 34.4 g/L, significantly higher than observed in common hydrogen producing fermentations. Acetate also accounted for more than 90% of soluble products formed in these fed-batch fermentations. The microbial community analysis revealed hydrogenotrophic methanogens (mainly Methanothermobacter thermautotrophicus and Methanobacterium thermoaggregans) as 98% of Archaea, confirming that high temperature will select hydrogenotrophic methanogens over aceticlastic methanogens effectively. This work demonstrated a potential application to effectively produce acetate as a value chemical and methane as an energy gas together via mixed culture fermentation.

  11. Synthetic polyester-hydrolyzing enzymes from thermophilic actinomycetes.

    Science.gov (United States)

    Wei, Ren; Oeser, Thorsten; Zimmermann, Wolfgang

    2014-01-01

    Thermophilic actinomycetes produce enzymes capable of hydrolyzing synthetic polyesters such as polyethylene terephthalate (PET). In addition to carboxylesterases, which have hydrolytic activity predominantly against PET oligomers, esterases related to cutinases also hydrolyze synthetic polymers. The production of these enzymes by actinomycetes as well as their recombinant expression in heterologous hosts is described and their catalytic activity against polyester substrates is compared. Assays to analyze the enzymatic hydrolysis of synthetic polyesters are evaluated, and a kinetic model describing the enzymatic heterogeneous hydrolysis process is discussed. Structure-function and structure-stability relationships of actinomycete polyester hydrolases are compared based on molecular dynamics simulations and recently solved protein structures. In addition, recent progress in enhancing their activity and thermal stability by random or site-directed mutagenesis is presented. © 2014 Elsevier Inc. All rights reserved.

  12. Feasibility of thermophilic anaerobic processes for treating waste activated sludge under low HRT and intermittent mixing.

    Science.gov (United States)

    Leite, Wanderli; Magnus, Bruna Scandolara; Guimarães, Lorena Bittencourt; Gottardo, Marco; Belli Filho, Paulo

    2017-10-01

    Thermophilic anaerobic digestion (AD) arises as an optimized solution for the waste activated sludge (WAS) management. However, there are few feasibility studies using low solids content typically found in the WAS, and that consider uncommon operational conditions such as intermittent mixing and low hydraulic retention time (HRT). In this investigation, a single-stage pilot reactor was used to treat WAS at low HRT (13, 9, 6 and 5 days) and intermittent mixing (withholding mixing 2 h prior feeding). Thermophilic anaerobic digestion (55 °C) was initiated from a mesophilic digester (35 °C) by the one-step startup strategy. Although instabilities on partial alkalinity (1245-3000 mgCaCO 3 /L), volatile fatty acids (1774-6421 mg/L acetic acid) and biogas production (0.21-0.09 m 3 /m 3 reactor .d) were observed, methanogenesis started to recover in 18 days. The thermophilic treatment of WAS at 13 and 9 days HRT efficiently converted VS into biogas (22 and 21%, respectively) and achieved high biogas yield (0.24 and 0.22 m 3 /kgVS fed , respectively). Intermittent mixing improved the retention of methanogens inside the reactor and reduced the washout effect even at low HRT (5% TS). Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Prospective of biodiesel production utilizing microalgae as the cell ...

    African Journals Online (AJOL)

    Microalgae are sunlight-driven miniature factories that convert atmospheric CO2 to polar and neutral lipids which after esterification can be utilized as an alternative source of petroleum. Further, other metabolic products such as bioethanol and biohydrogen produced by algal cells are also being considered for the same ...

  14. Dry thermophilic semi-continuous anaerobic digestion of food waste: Performance evaluation, modified Gompertz model analysis, and energy balance

    International Nuclear Information System (INIS)

    Nguyen, Dinh Duc; Chang, Soon Woong; Jeong, Seong Yeob; Jeung, Jaehoon; Kim, Sungsu; Guo, Wenshan; Ngo, Huu Hao

    2016-01-01

    Highlights: • Energy self-sufficiency/energy recovery with thermophilic DScAD of FW was evaluated. • The maximum biogas production rate was positively influenced by OLRs. • Maximum (average) electrical energy recoverable from a 1 tons of FW was 1050 kW h. • Thermophilic DScAD can substantially reduce the VS and recover energy to serve itself. • A modified Gompertz model fitted well with the experimental results for all phases. - Abstract: A thermophilic, dry semi-continuous anaerobic digestion (DScAD) method was used to effectively transform food waste (FW) into renewable energy. This study aims to thoroughly evaluate the system performance and model simulation to predict biogas production, intermediate products and their outcomes, energy recovery potential, and energy balance, while operating with organic loading rates ranging from 2.3 to 9.21 kg-TS/m"3 day. The results indicate that volatile solids (VS) reduction and biogas production both improved as the organic loading rates (OLR) increased, and the cost of FW valorization remained low. The greatest VS reduction achieved was 87.01%, associated with 170 m"3 of biogas yield per ton of sludge (69% methane) at an ORL of 9.21 ± 0.89 kg-TS/m"3 day (8.62 ± 0.34 kg-VS/m"3 day) although the amounts of ammonia (3700 mg/L), hydrogen sulfide (420 ppm), and total volatile fatty acids (7101 mg/L) during fermentation were relatively high. Furthermore, 75% of total energy requirement for the system could be recovered via biomethane production, resulting in a considerably reduced specific energy supply (kW h/ton of treating FW). The results suggest that a modified Gompertz model is suitable for estimating the biogas and methane production potential and rate. The results also reveal that the DScAD of FW at 55 °C is a reliable, stable, and robust option for both solids reduction and energy recovery via biogas generation.

  15. Acidogenic fermentation of Scenedesmus sp.-AMDD: Comparison of volatile fatty acids yields between mesophilic and thermophilic conditions.

    Science.gov (United States)

    Gruhn, Marvin; Frigon, Jean-Claude; Guiot, Serge R

    2016-01-01

    This study compared the acidogenic fermentation of Scenedesmus sp.-AMDD at laboratory-scale, under mesophilic (35°C) and thermophilic conditions (55°C). Preliminary batch tests were performed to evaluate best conditions for volatile fatty acid (VFA) production from microalgal biomass, with respect to the inoculum, pH and nutrients. The use of bovine manure as inoculum, the operating pH of 4.5 and the addition of a nutrient mix, resulted in a high VFA production of up to 222mgg(-1) total volatile solid (TVS), with a butyrate share of 27%. Both digesters displayed similar hydrolytic activity with 0.38±0.02 and 0.42±0.03 g soluble chemical oxygen demand (COD)g(-1) TVS for the digesters operated at 35 and 55°C, respectively. Mesophilic conditions were more favorable for VFA production, which reached 171±5, compared to 88±12 mg soluble CODg(-1) TVS added under thermophilic conditions (94% more). It was shown that in both digesters, butyrate was the predominant VFA. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  16. Improving anaerobic sewage sludge digestion by implementation of a hyper-thermophilic prehydrolysis step

    DEFF Research Database (Denmark)

    Lu, Jingquan; Gavala, Hariklia N.; Skiadas, Ioannis V.

    2008-01-01

    The present study focuses on a two-step process for treatment and stabilisation of primary sludge. The process consists of a hyperthermophilic hydrolysis step operated at 70 degrees C and a hydraulic retention time (HRT) of 2 clays followed by a thermophilic (55 degrees C) anaerobic digestion step......) with and Without pre-treatment respectively) and up to 115% increase of the methane production rate. Finally it was shown that the extra energy requirements for the operation of a pre-treatment step would be covered by the energy Produced from the extra methane production and in addition there would...

  17. Discrimination of thermophilic and mesophilic proteins

    Directory of Open Access Journals (Sweden)

    Vaisman Iosif I

    2010-05-01

    Full Text Available Abstract Background There is a considerable literature on the source of the thermostability of proteins from thermophilic organisms. Understanding the mechanisms for this thermostability would provide insights into proteins generally and permit the design of synthetic hyperstable biocatalysts. Results We have systematically tested a large number of sequence and structure derived quantities for their ability to discriminate thermostable proteins from their non-thermostable orthologs using sets of mesophile-thermophile ortholog pairs. Most of the quantities tested correspond to properties previously reported to be associated with thermostability. Many of the structure related properties were derived from the Delaunay tessellation of protein structures. Conclusions Carefully selected sequence based indices discriminate better than purely structure based indices. Combined sequence and structure based indices improve performance somewhat further. Based on our analysis, the strongest contributors to thermostability are an increase in ion pairs on the protein surface and a more strongly hydrophobic interior.

  18. [Conversion of acetic acid to methane by thermophiles

    Energy Technology Data Exchange (ETDEWEB)

    Zinder, S.H.

    1993-01-01

    The primary goal of this project is to obtain a better understanding of thermophilic microorganisms which convert acetic acid to CH[sub 4]. The previous funding period represents a departure from earlier research in this laboratory, which was more physiological and ecological. The present work is centered on the biochemistry of the thermophile Methanothrix sp. strain CALS-1. this organism presents a unique opportunity, with its purity and relatively rapid growth, to do comparative biochemical studies with the other major acetotrophic genus Methanosarcina. We previously found that Methanothrix is capable of using acetate at concentrations 100 fold lower than Methanosarcina. This finding suggests that there are significant differences in the pathways of methanogenesis from acetate in the two genera.

  19. Gamma irradiation induced disintegration of waste activated sludge for biological hydrogen production

    International Nuclear Information System (INIS)

    Yin, Yanan; Wang, Jianlong

    2016-01-01

    In this paper, gamma irradiation was applied for the disintegration and dissolution of waste activated sludge produced during the biological wastewater treatment, and the solubilized sludge was used as substrate for bio-hydrogen production. The experimental results showed that the solubilization of waste activated sludge was 53.7% at 20 kGy and pH=12, and the SCOD, polysaccharides, protein, TN and TP contents in the irradiated sludge solutions was 3789.6 mg/L, 268.3 mg/L, 1881.5 mg/L, 132.3 mg/L and 80.4 mg/L, respectively. The irradiated sludge was used for fermentative hydrogen production, and the hydrogen yield was 10.5±0.7 mL/g SCOD consumed . It can be concluded that the irradiated waste activated sludge could be used as a low-cost substrate for fermentative hydrogen production. - Highlights: • The waste activated sludge could be disintegrated by gamma irradiation. • The disintegrated sludge could be used for biohydrogen production. • The hydrogen yield was 10.5±0.7 mL/g SCOD consumed .

  20. Comprehensive microbial analysis of combined mesophilic anaerobic-thermophilic aerobic process treating high-strength food wastewater.

    Science.gov (United States)

    Jang, Hyun Min; Ha, Jeong Hyub; Park, Jong Moon; Kim, Mi-Sun; Sommer, Sven G

    2015-04-15

    A combined mesophilic anaerobic-thermophilic aerobic process was used to treat high-strength food wastewater in this study. During the experimental period, most of solid residue from the mesophilic anaerobic reactor (R1) was separated by centrifugation and introduced into the thermophilic aerobic reactor (R2) for further digestion. Then, thermophilic aerobically-digested sludge was reintroduced into R1 to enhance reactor performance. The combined process was operated with two different Runs: Run I with hydraulic retention time (HRT) = 40 d (corresponding OLR = 3.5 kg COD/m(3) d) and Run II with HRT = 20 d (corresponding OLR = 7 kg COD/m(3)). For a comparison, a single-stage mesophilic anaerobic reactor (R3) was operated concurrently with same OLRs and HRTs as the combined process. During the overall digestion, all reactors showed high stability without pH control. The combined process demonstrated significantly higher organic matter removal efficiencies (over 90%) of TS, VS and COD and methane production than did R3. Quantitative real-time PCR (qPCR) results indicated that higher populations of both bacteria and archaea were maintained in R1 than in R3. Pyrosequencing analysis revealed relatively high abundance of phylum Actinobacteria in both R1 and R2, and a predominance of phyla Synergistetes and Firmicutes in R3 during Run II. Furthermore, R1 and R2 shared genera (Prevotella, Aminobacterium, Geobacillus and Unclassified Actinobacteria), which suggests synergy between mesophilic anaerobic digestion and thermophilic aerobic digestion. For archaea, in R1 methanogenic archaea shifted from genus Methanosaeta to Methanosarcina, whereas genera Methanosaeta, Methanobacterium and Methanoculleus were predominant in R3. The results demonstrated dynamics of key microbial populations that were highly consistent with an enhanced reactor performance of the combined process. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Action of amylolytic and pullulytic enzymes from various anaerobic thermophiles on linear and branched glucose polymers

    Energy Technology Data Exchange (ETDEWEB)

    Koch, R [Goettingen Univ. (Germany, F.R.). Inst. fuer Mikrobiologie; Antranikian, G [Technische Univ. Hamburg-Harburg, Hamburg (Germany, F.R.). Arbeitsbereich Biotechnologie 1

    1990-10-01

    A detailed study has been conducted on the action of starch hydrolyzing enzymes from thermophilic anaerobic bacteria belonging to the genera Clostridium, Thermoanaerobacter and Thermobacteroides. The appearance of multiple bands on polyacrylamide gels with amylolytic as well as pullulytic activities was shown to be a general feature of bacteria investigated. Analysis of the hydrolysis products of each protein band clearly demonstrated the capability of these organisms to hydrolyze {alpha}-1,4-glycosidic bonds in linear oligosaccharides and {alpha}-1,6-glycosidic linkages in pullulan. Furthermore, the enzyme system of thermophilic bacteria investigated was also capable of attacking in the {alpha}-1,6-linkages in branched oligosaccharides. Due to the action of these thermoactive enzymes with multiple specificity an almost complete hydrolysis of raw starch and maltodextrin could be achieved under the same conditions and in one step. (orig.).

  2. In vivo and in vitro protein imaging in thermophilic archaea by exploiting a novel protein tag

    DEFF Research Database (Denmark)

    Visone, Valeria; Han, Wenyuan; Perugino, Giuseppe

    2017-01-01

    Protein imaging, allowing a wide variety of biological studies both in vitro and in vivo, is of great importance in modern biology. Protein and peptide tags fused to proteins of interest provide the opportunity to elucidate protein location and functions, detect protein-protein interactions, and ......, and allowed visualization of the enzyme in living cells. To the best of our knowledge, this is the first report of in vivo imaging of any protein of a thermophilic archaeon, filling an important gap in available tools for cell biology studies in these organisms....... to production of a functional H5 protein, which was successfully labeled with appropriate fluorescent molecules and visualized in cell extracts as well as in Δogt live cells. H5 was fused to reverse gyrase, a peculiar thermophile-specific DNA topoisomerase endowed with positive supercoiling activity...

  3. Exceptional thermal stability and organic solvent tolerance of an esterase expressed from a thermophilic host

    DEFF Research Database (Denmark)

    Mei, Yuxia; Peng, Nan; Zhao, Shumiao

    2012-01-01

    , giving SisEstA. Upon Escherichia coli expression, only the thioredoxin-tagged EstA recombinant protein was soluble. The fusion protein was then purified, and removing the protein tag yielded EcSisEstA. Both forms of the thermophilic EstA enzyme were characterized. We found that SisEstA formed dimer...... that of EcSisEstA at 90°C. This indicated that thermophilic enzymes yielded from homologous expression should be better biocatalysts than those obtained from mesophilic expression.......A protein expression system recently developed for the thermophilic crenarchaeon Sulfolobus islandicus was employed to produce recombinant protein for EstA, a thermophilic esterase encoded in the same organism. Large amounts of protein were readily obtained by an affinity protein purification...

  4. Dispersal of thermophilic Desulfotomaculum endospores into Baltic Sea sediments over thousands of years.

    Science.gov (United States)

    de Rezende, Júlia Rosa; Kjeldsen, Kasper Urup; Hubert, Casey R J; Finster, Kai; Loy, Alexander; Jørgensen, Bo Barker

    2013-01-01

    Patterns of microbial biogeography result from a combination of dispersal, speciation and extinction, yet individual contributions exerted by each of these mechanisms are difficult to isolate and distinguish. The influx of endospores of thermophilic microorganisms to cold marine sediments offers a natural model for investigating passive dispersal in the ocean. We investigated the activity, diversity and abundance of thermophilic endospore-forming sulfate-reducing bacteria (SRB) in Aarhus Bay by incubating pasteurized sediment between 28 and 85 °C, and by subsequent molecular diversity analyses of 16S rRNA and of the dissimilatory (bi)sulfite reductase (dsrAB) genes within the endospore-forming SRB genus Desulfotomaculum. The thermophilic Desulfotomaculum community in Aarhus Bay sediments consisted of at least 23 species-level 16S rRNA sequence phylotypes. In two cases, pairs of identical 16S rRNA and dsrAB sequences in Arctic surface sediment 3000 km away showed that the same phylotypes are present in both locations. Radiotracer-enhanced most probable number analysis revealed that the abundance of endospores of thermophilic SRB in Aarhus Bay sediment was ca. 10(4) per cm(3) at the surface and decreased exponentially to 10(0) per cm(3) at 6.5 m depth, corresponding to 4500 years of sediment age. Thus, a half-life of ca. 300 years was estimated for the thermophilic SRB endospores deposited in Aarhus Bay sediments. These endospores were similarly detected in the overlying water column, indicative of passive dispersal in water masses preceding sedimentation. The sources of these thermophiles remain enigmatic, but at least one source may be common to both Aarhus Bay and Arctic sediments.

  5. γ-irradiation resistance and UV-sensitivity of extremely thermophilic archebacteria and eubacteria

    International Nuclear Information System (INIS)

    Kopylov, V.M.; Bonch-Osmolovskaya, E.A.; Svetlichnyi, V.A.; Miroshnichenko, M.L.; Skobkin, V.S.

    1993-01-01

    Cells of extremely thermophilic sulfur-dependent archebacteria Desulfurococcus amylolyticus Z533 and Thermococcus stelleri K15 are resistant to γ-irradiation. These archebacteria survive γ-irradiation at a dose of up to 5 kGy but are no longer viable after 8-9 kGy. Comparison of the survival profiles showed that archebacteria are 12 to 25 times more resistant to γ-irradiation at moderate doses (LD 50 and LD 90 ) than E. coli K12 but are 2 to 2.5 times more sensitive than D. radiodurans. γ-irradiation at a dose of 1 to 2.5 kGy killed extremely thermophilic anaerobic eubacteria Thermotoga maritima 2706 and Thermodesulfobacterium P. All extreme thermophiles studied were more sensitive to UV-irradiation than E. coli

  6. Xylanases of thermophilic bacteria from Icelandic hot springs

    Energy Technology Data Exchange (ETDEWEB)

    Pertulla, M; Raettoe, M; Viikari, L [VTT, Biotechnical Lab., Espoo (Finland); Kondradsdottir, M [Dept. of Biotechnology, Technological Inst. of Iceland, Reykjavik (Iceland); Kristjansson, J K [Dept. of Biotechnology, Technological Inst. of Iceland, Reykjavik (Iceland) Inst. of Biotechnology, Iceland Univ., Reykjavik (Iceland)

    1993-02-01

    Thermophilic, aerobic bacteria isolated from Icelandic hot springs were screened for xylanase activity. Of 97 strains tested, 14 were found to be xylanase positive. Xylanase activities up to 12 nkat/ml were produced by these strains in shake flasks on xylan medium. The xylanases of the two strains producing the highest activities (ITI 36 and ITI 283) were similar with respect to temperature and pH optima (80deg C and pH 8.0). Xylanase production of strain ITI 36 was found to be induced by xylan and xylose. Xylanase activity of 24 nkat/ml was obtained with this strain in a laboratory-scale-fermentor cultivation on xylose medium. [beta]-Xylosidase activity was also detected in the culture filtrate. The thermal half-life of ITI 36 xylanase was 24 h at 70deg C. The highest production of sugars from hydrolysis of beech xylan was obtained at 70deg C, although xylan depolymerization was detected even up to 90deg C. (orig.).

  7. Molecular Characterization and Expression of a Phytase Gene from the Thermophilic Fungus Thermomyces lanuginosus

    Science.gov (United States)

    Berka, Randy M.; Rey, Michael W.; Brown, Kimberly M.; Byun, Tony; Klotz, Alan V.

    1998-01-01

    The phyA gene encoding an extracellular phytase from the thermophilic fungus Thermomyces lanuginosus was cloned and heterologously expressed, and the recombinant gene product was biochemically characterized. The phyA gene encodes a primary translation product (PhyA) of 475 amino acids (aa) which includes a putative signal peptide (23 aa) and propeptide (10 aa). The deduced amino acid sequence of PhyA has limited sequence identity (ca. 47%) with Aspergillus niger phytase. The phyA gene was inserted into an expression vector under transcriptional control of the Fusarium oxysporum trypsin gene promoter and used to transform a Fusarium venenatum recipient strain. The secreted recombinant phytase protein was enzymatically active between pHs 3 and 7.5, with a specific activity of 110 μmol of inorganic phosphate released per min per mg of protein at pH 6 and 37°C. The Thermomyces phytase retained activity at assay temperatures up to 75°C and demonstrated superior catalytic efficiency to any known fungal phytase at 65°C (the temperature optimum). Comparison of this new Thermomyces catalyst with the well-known Aspergillus niger phytase reveals other favorable properties for the enzyme derived from the thermophilic gene donor, including catalytic activity over an expanded pH range. PMID:9797301

  8. Molecular characterization of thermophilic Campylobacter species ...

    African Journals Online (AJOL)

    We identified two species of thermophilic Campylobacter in companion dogs in Jos. Majority of C. jejuni were isolated from mucoid faeces while mixed infections of the two species were more common among diarrhoeic dogs. Pet owners should observe strict hand hygiene especially after handling dogs or their faeces to ...

  9. Defluviitalea phaphyphila sp. nov., a Novel Thermophilic Bacterium That Degrades Brown Algae.

    Science.gov (United States)

    Ji, Shi-Qi; Wang, Bing; Lu, Ming; Li, Fu-Li

    2016-02-01

    Brown algae are one of the largest groups of oceanic primary producers for CO2 removal and carbon sinks for coastal regions. However, the mechanism for brown alga assimilation remains largely unknown in thermophilic microorganisms. In this work, a thermophilic alginolytic community was enriched from coastal sediment, from which an obligate anaerobic and thermophilic bacterial strain, designated Alg1, was isolated. Alg1 shared a 16S rRNA gene identity of 94.6% with Defluviitalea saccharophila LIND6LT2(T). Phenotypic, chemotaxonomic, and phylogenetic studies suggested strain Alg1 represented a novel species of the genus Defluviitalea, for which the name Defluviitalea phaphyphila sp. nov. is proposed. Alg1 exhibited an intriguing ability to convert carbohydrates of brown algae, including alginate, laminarin, and mannitol, to ethanol and acetic acid. Three gene clusters participating in this process were predicted to be in the genome, and candidate enzymes were successfully expressed, purified, and characterized. Six alginate lyases were demonstrated to synergistically deconstruct alginate into unsaturated monosaccharide, followed by one uronic acid reductase and two 2-keto-3-deoxy-d-gluconate (KDG) kinases to produce pyruvate. A nonclassical mannitol 1-phosphate dehydrogenase, catalyzing D-mannitol 1-phosphate to fructose 1-phosphate in the presence of NAD(+), and one laminarase also were disclosed. This work revealed that a thermophilic brown alga-decomposing system containing numerous novel thermophilic alginate lyases and a unique mannitol 1-phosphate dehydrogenase was adopted by the natural ethanologenic strain Alg1 during the process of evolution in hostile habitats. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  10. Thermophilic bacteria in Moroccan hot springs, salt marshes and desert soils

    OpenAIRE

    Aanniz,Tarik; Ouadghiri,Mouna; Melloul,Marouane; Swings,Jean; Elfahime,Elmostafa; Ibijbijen,Jamal; Ismaili,Mohamed; Amar,Mohamed

    2015-01-01

    The diversity of thermophilic bacteria was investigated in four hot springs, three salt marshes and 12 desert sites in Morocco. Two hundred and forty (240) thermophilic bacteria were recovered, identified and characterized. All isolates were Gram positive, rod-shaped, spore forming and halotolerant. Based on BOXA1R-PCR and 16S rRNA gene sequencing, the recovered isolates were dominated by the genus Bacillus (97.5%) represented by B. licheniformis (119), B. aerius (44), B. sonorensis (33), B. ...

  11. Aspergillus fumigatus and other thermophilic fungi in nests of wetland birds.

    Science.gov (United States)

    Korniłłowicz-Kowalska, Teresa; Kitowski, Ignacy

    2013-02-01

    A study was performed on the numbers and species diversity of thermophilic fungi (growing at 45 °C in vitro) in 38 nests of 9 species of wetland birds, taking into account the physicochemical properties of the nests and the bird species. It was found that in nests with the maximum weight (nests of Mute Swan), the number and diversity of thermophilic fungi were significantly greater than in other nests, with lower weight. The diversity of the thermophilic biota was positively correlated with the individual mass of bird and with the level of phosphorus in the nests. The dominant species within the mycobiota under study was Aspergillus fumigatus which inhabited 95% of the nests under study, with average frequency of ca. 650 cfu g(-1) of dry mass of the nest material. In a majority of the nests studied (nests of 7 bird species), the share of A. fumigatus exceeded 50% of the total fungi growing at 45 °C. Significantly higher frequencies of the fungal species were characteristic of the nests of small and medium-sized piscivorous species, compared with the other bird species. The number of A. fumigatus increased with increase in the moisture level of the nests, whereas the frequency of occurrence of that opportunistic pathogen, opposite to the general frequency of thermophilic mycobiota, was negatively correlated with the level of phosphorus in the nest material, and with the body mass and length of the birds. The authors indicate the causes of varied growth of thermophilic fungi in nests of wetland birds and, in particular, present a discussion of the causes of accumulation of A. fumigatus, the related threats to the birds, and its role as a source of transmission in the epidemiological chain of aspergillosis.

  12. Efficient plant biomass degradation by thermophilic fungus Myceliophthora heterothallica.

    Science.gov (United States)

    van den Brink, Joost; van Muiswinkel, Gonny C J; Theelen, Bart; Hinz, Sandra W A; de Vries, Ronald P

    2013-02-01

    Rapid and efficient enzymatic degradation of plant biomass into fermentable sugars is a major challenge for the sustainable production of biochemicals and biofuels. Enzymes that are more thermostable (up to 70°C) use shorter reaction times for the complete saccharification of plant polysaccharides compared to hydrolytic enzymes of mesophilic fungi such as Trichoderma and Aspergillus species. The genus Myceliophthora contains four thermophilic fungi producing industrially relevant thermostable enzymes. Within this genus, isolates belonging to M. heterothallica were recently separated from the well-described species M. thermophila. We evaluate here the potential of M. heterothallica isolates to produce efficient enzyme mixtures for biomass degradation. Compared to the other thermophilic Myceliophthora species, isolates belonging to M. heterothallica and M. thermophila grew faster on pretreated spruce, wheat straw, and giant reed. According to their protein profiles and in vitro assays after growth on wheat straw, (hemi-)cellulolytic activities differed strongly between M. thermophila and M. heterothallica isolates. Compared to M. thermophila, M. heterothallica isolates were better in releasing sugars from mildly pretreated wheat straw (with 5% HCl) with a high content of xylan. The high levels of residual xylobiose revealed that enzyme mixtures of Myceliophthora species lack sufficient β-xylosidase activity. Sexual crossing of two M. heterothallica showed that progenies had a large genetic and physiological diversity. In the future, this will allow further improvement of the plant biomass-degrading enzyme mixtures of M. heterothallica.

  13. Effect of feed to microbe ratios on anaerobic digestion of Chinese cabbage waste under mesophilic and thermophilic conditions: biogas potential and kinetic study.

    Science.gov (United States)

    Kafle, Gopi Krishna; Bhattarai, Sujala; Kim, Sang Hun; Chen, Lide

    2014-01-15

    The objective of this study was to investigate the effect of the feed-to-microbe (F/M) ratios on anaerobic digestion of Chinese cabbage waste (CCW) generated from a kimchi factory. The batch test was conducted for 96 days under mesophilic (36.5 °C) (Experiment I) and thermophilic (55 °C) conditions (Experiment II) at F/M ratios of 0.5, 1.0 and 2.0. The first-order kinetic model was evaluated for methane yield. The biogas yield in terms of volatile solids (VS) added increased from 591 to 677 mL/g VS under mesophilic conditions and 434 to 639 mL/g VS under thermophilic conditions when the F/M ratio increased from 0.5 to 2.0. Similarly, the volumetric biogas production increased from 1.479 to 6.771 L/L under mesophilic conditions and from 1.086 to 6.384 L/L under thermophilic conditions when F/M ratio increased from 0.5 to 2.0. The VS removal increased from 59.4 to 75.6% under mesophilic conditions and from 63.5 to 78.3% under thermophilic conditions when the F/M ratio increased from 0.5 to 2.0. The first-order kinetic constant (k, 1/day) decreased under the mesophilic temperature conditions and increased under thermophilic conditions when the F/M ratio increased from 0.5 to 2.0. The difference between the experimental and predicted methane yield was in the range of 3.4-14.5% under mesophilic conditions and in the range of 1.1-3.0% under thermophilic conditions. The predicted methane yield derived from the first-order kinetic model was in good agreement with the experimental results. Published by Elsevier Ltd.

  14. Nicotinamidase from the thermophilic archaeon Acidilobus saccharovorans: structural and functional characteristics.

    Science.gov (United States)

    Stekhanova, T N; Bezsudnova, E Y; Mardanov, A V; Osipov, E M; Ravin, N V; Skryabin, K G; Popov, V O

    2014-01-01

    Nicotinamidase is involved in the maintenance of NAD+ homeostasis and in the NAD+ salvage pathway of most prokaryotes, and it is considered as a possible drug target. The gene (ASAC_0847) encoding a hypothetical nicotinamidase has been found in the genome of the thermophilic archaeon Acidilobus saccharovorans. The product of this gene, NA_As0847, has been expressed in Escherichia coli, isolated, and characterized as a Fe(2+)-containing nicotinamidase (k(cat)/K(m) = 427 mM(-1)·sec(-1))/pyrazinamidase (k(cat)/K(m) = 331 mM(-1)·sec(-1)). NA_As0847 is a homodimer with molecular mass 46.4 kDa. The enzyme has high thermostability (T(1/2) (60°C) = 180 min, T(1/2) (80°C) = 35 min) and thermophilicity (T(opt) = 90°C, E(a) = 30.2 ± 1.0 kJ/mol) and broad pH interval of activity, with the optimum at pH 7.5. Special features of NA_As0847 are the presence of Fe2+ instead of Zn2+ in the active site of the enzyme and inhibition of the enzyme activity by Zn2+ at micromolar concentrations. Analysis of the amino acid sequence revealed a new motif of the metal-binding site (DXHXXXDXXEXXXWXXH) for homological archaeal nicotinamidases.

  15. Effects of acetylene and carbon monoxide on long-term hydrogen production by Mastigocladus laminosus, a thermophilic blue-green alga

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Y; Yokoyama, H; Takahara, K; Miyamoto, K

    1982-01-01

    Long-term H/sub 2/ production by a thermophilic and heterocystous blue-green alga (cyanobacterium) Mastigocladus laminosus was studied under the conditions when acetylene and carbon monoxide were supplemented to the gas phase of the culture vessel. The addition of both gases enhanced H/sub 2/ evolution by nitrogen-starved cells. The concentrations of acetylene and carbon monoxide in the gas phase of argon/CO/sub 2/ (97.5/2.5) were 10% and 0.2 to 1%, respectively, for the maximum H/sub 2/ production. Renewals of the gas phase, in addition to the addition of acetylene and carbon monoxide, were necessary for durable H/sub 2/ production. Since the concentrations of both H/sub 2/ and O/sub 2/ accumulated in the gas phase were minimized after the renewals, the H/sub 2/ uptake activity, which was not completely inhibited by acetylene and carbon monoxide, was reduced and thereby H/sub 2/ evolution was restored. Under such conditions, H/sub 2/ production for up to 20 days was observed under argon and N/sub 2/ atmospheres with average rats of 3.9 and 3.3..mu..l/mg dry wt/h, respectively. H/sub 2/ evolution for 15 days was observed even under an air atmosphere containing acetylene and carbon monoxide. It was thus shown that prolonged production of H/sub 2/ was possible by the use of a blue-green alga which exhibits a high activity of H/sub 2/ uptake under nitrogen-starved conditions.

  16. Bacillus sp. JR3 esterase LipJ: A new mesophilic enzyme showing traces of a thermophilic past.

    Directory of Open Access Journals (Sweden)

    Judit Ribera

    Full Text Available A search for extremophile enzymes from ancient volcanic soils in El Hierro Island (Canary Islands, Spain allowed isolation of a microbial sporulated strain collection from which several enzymatic activities were tested. Isolates were obtained after sample cultivation under several conditions of nutrient contents and temperature. Among the bacterial isolates, supernatants from the strain designated JR3 displayed high esterase activity at temperatures ranging from 30 to 100°C, suggesting the presence of at least a hyper-thermophilic extracellular lipase. Sequence alignment of known thermophilic lipases allowed design of degenerated consensus primers for amplification and cloning of the corresponding lipase, named LipJ. However, the cloned enzyme displayed maximum activity at 30°C and pH 7, showing a different profile from that observed in supernatants of the parental strain. Sequence analysis of the cloned protein showed a pentapeptide motif -GHSMG- distinct from that of thermophilic lipases, and much closer to that of esterases. Nevertheless, the 3D structural model of LipJ displayed the same folding as that of thermophilic lipases, suggesting a common evolutionary origin. A phylogenetic study confirmed this possibility, positioning LipJ as a new member of the thermophilic family of bacterial lipases I.5. However, LipJ clusters in a clade close but separated from that of Geobacillus sp. thermophilic lipases. Comprehensive analysis of the cloned enzyme suggests a common origin of LipJ and other bacterial thermophilic lipases, and highlights the most probable divergent evolutionary pathway followed by LipJ, which during the harsh past times would have probably been a thermophilic enzyme, having lost these properties when the environment changed to more benign conditions.

  17. Bacillus sp. JR3 esterase LipJ: A new mesophilic enzyme showing traces of a thermophilic past.

    Science.gov (United States)

    Ribera, Judit; Estupiñán, Mónica; Fuentes, Alba; Fillat, Amanda; Martínez, Josefina; Diaz, Pilar

    2017-01-01

    A search for extremophile enzymes from ancient volcanic soils in El Hierro Island (Canary Islands, Spain) allowed isolation of a microbial sporulated strain collection from which several enzymatic activities were tested. Isolates were obtained after sample cultivation under several conditions of nutrient contents and temperature. Among the bacterial isolates, supernatants from the strain designated JR3 displayed high esterase activity at temperatures ranging from 30 to 100°C, suggesting the presence of at least a hyper-thermophilic extracellular lipase. Sequence alignment of known thermophilic lipases allowed design of degenerated consensus primers for amplification and cloning of the corresponding lipase, named LipJ. However, the cloned enzyme displayed maximum activity at 30°C and pH 7, showing a different profile from that observed in supernatants of the parental strain. Sequence analysis of the cloned protein showed a pentapeptide motif -GHSMG- distinct from that of thermophilic lipases, and much closer to that of esterases. Nevertheless, the 3D structural model of LipJ displayed the same folding as that of thermophilic lipases, suggesting a common evolutionary origin. A phylogenetic study confirmed this possibility, positioning LipJ as a new member of the thermophilic family of bacterial lipases I.5. However, LipJ clusters in a clade close but separated from that of Geobacillus sp. thermophilic lipases. Comprehensive analysis of the cloned enzyme suggests a common origin of LipJ and other bacterial thermophilic lipases, and highlights the most probable divergent evolutionary pathway followed by LipJ, which during the harsh past times would have probably been a thermophilic enzyme, having lost these properties when the environment changed to more benign conditions.

  18. Influence of variable feeding on mesophilic and thermophilic co-digestion of Laminaria digitata and cattle manure

    International Nuclear Information System (INIS)

    Sarker, Shiplu; Møller, Henrik Bjarne; Bruhn, Annette

    2014-01-01

    Highlights: • Anaerobic co-digestion of L. digitata and cattle manure, at ∼35 and ∼50 °C. • Mesophilic co-digestion showed somewhat stable specific methane, but increased volumetric yield. • Thermophilic co-digester yielded higher methane at higher input of algae compared to control. • Mesophilic co-digester performed better in terms of various parameters except methane yield. - Abstract: In this study the effect of various feeding ratios on mesophilic (∼35 °C) and thermophilic (∼50 °C) co-digestion of brown algae Laminaria digitata and cattle manure was investigated. Algae input of 15% VS caused no influence on specific methane yield from mesophilic co-digester while deteriorated the process parameters such as the development of propionic acid in total volatile fatty acids (tVFA) pattern of the thermophilic co-digester. The accumulation of tVFA continued for the latter reactor as the feeding ratio of algae enhanced to 24% VS, but the specific methane yield improved dramatically. Same rise in feeding once again showed no improvement in specific methane yield from mesophilic co-digester even though the other process parameters stabilized or, enriched such as the gain in average volumetric methane yield. For the last feeding ratio at 41% VS algae, specific methane yield from mesophilic co-digester slightly increased which however was not still comparable with the ultimate methane yield from the cattle manure alone. The thermophilic co-digestion on the other hand yielded maximum specific methane, together with the improvement in different process characteristics, as the feeding of algae maximized at the final stage. The trend of methane production from this reactor nevertheless was sharply downward towards the end of the experiment suggesting that the optimum feeding ratio has already been achieved for the present experimental conditions

  19. Hydrolytic bacteria in mesophilic and thermophilic degradation of plant biomass

    Energy Technology Data Exchange (ETDEWEB)

    Zverlov, Vladimir V.; Hiegl, Wolfgang; Koeck, Daniela E.; Koellmeier, Tanja; Schwarz, Wolfgang H. [Department of Microbiology, Technische Universitaet Muenchen, Freising-Weihenstephan (Germany); Kellermann, Josef [Max Planck Institute for Biochemistry, Am Klopferspitz, Martinsried (Germany)

    2010-12-15

    Adding plant biomass to a biogas reactor, hydrolysis is the first reaction step in the chain of biological events towards methane production. Maize silage was used to enrich efficient hydrolytic bacterial consortia from natural environments under conditions imitating those in a biogas plant. At 55-60 C a more efficient hydrolyzing culture could be isolated than at 37 C. The composition of the optimal thermophilic bacterial consortium was revealed by sequencing clones from a 16S rRNA gene library. A modified PCR-RFLP pre-screening method was used to group the clones. Pure anaerobic cultures were isolated. 70% of the isolates were related to Clostridium thermocellum. A new culture-independent method for identification of cellulolytic enzymes was developed using the isolation of cellulose-binding proteins. MALDI-TOF/TOF analysis and end-sequencing of peptides from prominent protein bands revealed cellulases from the cellulosome of C. thermocellum and from a major cellulase of Clostridium stercorarium. A combined culture of C. thermocellum and C. stercorarium was shown to excellently degrade maize silage. A spore preparation method suitable for inoculation of maize silage and optimal hydrolysis was developed for the thermophilic bacterial consortium. This method allows for concentration and long-term storage of the mixed culture for instance for inoculation of biogas fermenters. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Mesophilic and thermophilic anaerobic digestion of biologically pretreated abattoir wastewaters in an upflow anaerobic filter

    International Nuclear Information System (INIS)

    Gannoun, H.; Bouallagui, H.; Okbi, A.; Sayadi, S.; Hamdi, M.

    2009-01-01

    The hydrolysis pretreatment of abattoir wastewaters (AW), rich in organic suspended solids (fats and protein) was studied in static and stirred batch reactors without aeration in the presence of natural microbial population acclimated in a storage tank of AW. Microbial analysis showed that the major populations which contribute to the pretreatment of AW belong to the genera Bacillus. Contrary to the static pretreatment, the stirred conditions favoured the hydrolysis and solubilization of 80% of suspended matter into soluble pollution. The pretreated AW, in continuous stirred tank reactor (CSTR) at a hydraulic retention time (HRT) of 2 days, was fed to an upflow anaerobic filter (UAF) at an HRT of 2 days. The performance of anaerobic digestion of biologically pretreated AW was examined under mesophilic (37 deg. C) and thermophilic (55 deg. C) conditions. The shifting from a mesophilic to a thermophilic environment in the UAF was carried out with a short start-up of thermophilic condition. The UAF ran at organic loading rates (OLRs) ranging from 0.9 to 6 g COD/L d in mesophilic conditions and at OLRs from 0.9 to 9 g COD/L d in thermophilic conditions. COD removal efficiencies of 80-90% were achieved for OLRs up to 4.5 g COD/L d in mesophilic conditions, while the highest OLRs i.e. 9 g COD/L d led to efficiencies of 70-72% in thermophilic conditions. The biogas yield in thermophilic conditions was about 0.32-0.45 L biogas/g of COD removed for OLRs up to 4.5 g COD/L d. For similar OLR, the UAF in mesophilic conditions showed lower percentage of methanization. Mesophilic anaerobic digestion has been shown to destroy pathogens partially, whereas the thermophilic process was more efficient in the removal of indicator microorganisms and pathogenic bacteria at different organic loading rates.

  1. Molecular diversity of thermophilic bacteria isolated from Pasinler hot spring (Erzurum, Turkey)

    OpenAIRE

    ADIGÜZEL, Ahmet; İNAN, Kadriye; ŞAHİN, Fikrettin; ARASOĞLU, Tulin; GÜLLÜCE, Medine

    2011-01-01

    The present study was conducted to determine the phenotypic and genotypic characterization of thermophilic bacteria isolated from Pasinler hot spring, Erzurum, Turkey. Fatty acid profiles, BOX PCR fingerprints, and 16S rDNA sequence data were used for the phenotypic and genotypic characterization of thermophilic bacteria. Totally 9 different bacterial strains were selected based on morphological, physiological, and biochemical tests. These strains were characterized by molecular tests includi...

  2. Estimation of extracellular lipase enzyme produced by thermophilic bacillus sp. isolated from arid and semi-arid region of Rajasthan, India

    OpenAIRE

    Deeksha Gaur; Pankaj Kumar Jain; Yamini Singh Sisodia; Vivek Bajpai

    2012-01-01

    Thermophilic organisms can be defined as microorganisms which are adapted to live at high temperatures. The enzymes produce by thermophilic bacteria are capable of catalyzing biochemical reactions at high temperatures. Thermophilic bacteria are able to produce thermostable lipase enzymes capable of degradation of lipid at temperatures higher than those of mesophilic bacteria. Therefore, the isolation of thermophilic bacteria from natural sources and their identification are quite useful in te...

  3. Screening of complex thermophilic microbial community and ...

    African Journals Online (AJOL)

    Screening of complex thermophilic microbial community and application during municipal solid waste aerobic composting. ... African Journal of Biotechnology ... Complex microbial community HP83 and HC181 were applied during municipal solid waste aerobic composting that was carried out in a composting reactor under ...

  4. Dry co-digestion of sewage sludge and rice straw under mesophilic and thermophilic anaerobic conditions.

    Science.gov (United States)

    Chu, Xiangqian; Wu, Guangxue; Wang, Jiaquan; Hu, Zhen-Hu

    2015-12-01

    Dry anaerobic digestion of sewage sludge can recover biogas as energy; however, its low C/N ratio limits it as a single substrate in the anaerobic digestion. Rice straw is an abundant agricultural residue in China, which is rich in carbon and can be used as carbon source. In the present study, the performance of dry co-digestion of sewage sludge and rice straw was investigated under mesophilic (35 °C) and thermophilic (55 °C) conditions. The operational factors impacting dry co-digestion of sewage sludge and rice straw such as C/N ratio, moisture content, and initial pH were explored under mesophilic conditions. The results show that low C/N ratios resulted in a higher biogas production rate, but a lower specific biogas yield; low moisture content of 65 % resulted in the instability of the digestion system and a low specific biogas yield. Initial pH ranging 7.0-9.0 did not affect the performance of the anaerobic digestion. The C/N ratio of 26-29:1, moisture content of 70-80 %, and pH 7.0-9.0 resulted in good performance in the dry mesophilic co-digestion of sewage sludge and rice straw. As compared with mesophilic digestion, thermophilic co-digestion of sewage sludge and rice straw significantly enhanced the degradation efficiency of the substrates and the specific biogas yield (p sewage sludge under mesophilic and thermophilic conditions.

  5. Thermophilic bacteria in Moroccan hot springs, salt marshes and desert soils.

    Science.gov (United States)

    Aanniz, Tarik; Ouadghiri, Mouna; Melloul, Marouane; Swings, Jean; Elfahime, Elmostafa; Ibijbijen, Jamal; Ismaili, Mohamed; Amar, Mohamed

    2015-06-01

    The diversity of thermophilic bacteria was investigated in four hot springs, three salt marshes and 12 desert sites in Morocco. Two hundred and forty (240) thermophilic bacteria were recovered, identified and characterized. All isolates were Gram positive, rod-shaped, spore forming and halotolerant. Based on BOXA1R-PCR and 16S rRNA gene sequencing, the recovered isolates were dominated by the genus Bacillus (97.5%) represented by B. licheniformis (119), B. aerius (44), B. sonorensis (33), B. subtilis (subsp. spizizenii (2) and subsp. inaquosurum (6)), B. amyloliquefaciens (subsp. amyloliquefaciens (4) and subsp. plantarum (4)), B. tequilensis (3), B. pumilus (3) and Bacillus sp. (19). Only six isolates (2.5%) belonged to the genus Aeribacillus represented by A. pallidus (4) and Aeribacillus sp. (2). In this study, B. aerius and B. tequilensis are described for the first time as thermophilic bacteria. Moreover, 71.25%, 50.41% and 5.41% of total strains exhibited high amylolytic, proteolytic or cellulolytic activity respectively.

  6. Thermophilic bacteria in Moroccan hot springs, salt marshes and desert soils

    Directory of Open Access Journals (Sweden)

    Tarik Aanniz

    2015-06-01

    Full Text Available The diversity of thermophilic bacteria was investigated in four hot springs, three salt marshes and 12 desert sites in Morocco. Two hundred and forty (240 thermophilic bacteria were recovered, identified and characterized. All isolates were Gram positive, rod-shaped, spore forming and halotolerant. Based on BOXA1R-PCR and 16S rRNA gene sequencing, the recovered isolates were dominated by the genus Bacillus (97.5% represented by B. licheniformis (119, B. aerius (44, B. sonorensis (33, B. subtilis (subsp. spizizenii (2 and subsp. inaquosurum (6, B. amyloliquefaciens (subsp. amyloliquefaciens (4 and subsp. plantarum (4, B. tequilensis (3, B. pumilus (3 and Bacillus sp. (19. Only six isolates (2.5% belonged to the genus Aeribacillus represented by A. pallidus (4 and Aeribacillus sp. (2. In this study, B. aerius and B. tequilensis are described for the first time as thermophilic bacteria. Moreover, 71.25%, 50.41% and 5.41% of total strains exhibited high amylolytic, proteolytic or cellulolytic activity respectively.

  7. Widespread Disulfide Bonding in Proteins from Thermophilic Archaea

    Directory of Open Access Journals (Sweden)

    Julien Jorda

    2011-01-01

    Full Text Available Disulfide bonds are generally not used to stabilize proteins in the cytosolic compartments of bacteria or eukaryotic cells, owing to the chemically reducing nature of those environments. In contrast, certain thermophilic archaea use disulfide bonding as a major mechanism for protein stabilization. Here, we provide a current survey of completely sequenced genomes, applying computational methods to estimate the use of disulfide bonding across the Archaea. Microbes belonging to the Crenarchaeal branch, which are essentially all hyperthermophilic, are universally rich in disulfide bonding while lesser degrees of disulfide bonding are found among the thermophilic Euryarchaea, excluding those that are methanogenic. The results help clarify which parts of the archaeal lineage are likely to yield more examples and additional specific data on protein disulfide bonding, as increasing genomic sequencing efforts are brought to bear.

  8. Widespread disulfide bonding in proteins from thermophilic archaea.

    Science.gov (United States)

    Jorda, Julien; Yeates, Todd O

    2011-01-01

    Disulfide bonds are generally not used to stabilize proteins in the cytosolic compartments of bacteria or eukaryotic cells, owing to the chemically reducing nature of those environments. In contrast, certain thermophilic archaea use disulfide bonding as a major mechanism for protein stabilization. Here, we provide a current survey of completely sequenced genomes, applying computational methods to estimate the use of disulfide bonding across the Archaea. Microbes belonging to the Crenarchaeal branch, which are essentially all hyperthermophilic, are universally rich in disulfide bonding while lesser degrees of disulfide bonding are found among the thermophilic Euryarchaea, excluding those that are methanogenic. The results help clarify which parts of the archaeal lineage are likely to yield more examples and additional specific data on protein disulfide bonding, as increasing genomic sequencing efforts are brought to bear.

  9. Evolvability of thermophilic proteins from archaea and bacteria.

    Science.gov (United States)

    Takano, Kazufumi; Aoi, Atsushi; Koga, Yuichi; Kanaya, Shigenori

    2013-07-16

    Proteins from thermophiles possess high thermostability. The stabilization mechanisms differ between archaeal and bacterial proteins, whereby archaeal proteins are mainly stabilized via hydrophobic interactions and bacterial proteins by ion pairs. High stability is an important factor in promoting protein evolution, but the precise means by which different stabilization mechanisms affect the evolution process remain unclear. In this study, we investigated a random mutational drift of esterases from thermophilic archaea and bacteria at high temperatures. Our results indicate that mutations in archaeal proteins lead to improved function with no loss of stability, while mutant bacterial proteins are largely destabilized with decreased activity at high temperatures. On the basis of these findings, we suggest that archaeal proteins possess higher "evolvability" than bacterial proteins under temperature selection and are additionally able to evolve into eukaryotic proteins.

  10. A novel biological hydrogen production system. Impact of organic loading

    Energy Technology Data Exchange (ETDEWEB)

    Hafez, Hisham; Nakhla, George; El Naggar, Hesham [Western Ontario Univ. (Canada)

    2010-07-01

    The patent-pending system comprises a novel biohydrogen reactor with a gravity settler for decoupling of SRT from HRT. Two biohydrogenators were operated for 220 days at 37 C, hydraulic retention time 8 h and solids retention time ranged from 1.4 to 2 days under four different glucose concentrations of 2, 8, 16, 32, 48 and 64 g/L, corresponding to organic loading rates of 6.5-206 kg COD/m{sup 3}-d, and started up using anaerobically-digested sludge from the St. Marys wastewater treatment plant (St.Mary, Ontario, Canada) as the seed. The system steadily produced hydrogen with no methane. A maximum hydrogen yield of 3.1 mol H{sub 2} /mol glucose was achieved in the system for all the organic loading rates with an average of 2.8mol H{sub 2} /mol glucose. Acetate and butyrate were the main effluent liquid products at concentrations ranging from 640-7400 mg/L and 400-4600 mg/l, respectively, with no lactate detection. Microbial community analysis using denaturing gradient gel electrophoresis (DGGE) confirmed the absence of lactate producing bacteria Lactobacillus fermentum and other non-hydrogen producing species, and the predominance of various Clostridium species. Biomass concentrations in the biohydrogenators were steady, during the runs, varying form 1500 mg/L at the OLR of 6.5 kg COD/m{sup 3}-d to 14000 mg/L at the 104 kg COD/m{sup 3}-d, thus emphasizing the potential of this novel system for sustained stable hydrogen production and prevention of biomass washout. (orig.)

  11. Optimization of biohydrogen and methane recovery within a cassava ethanol wastewater/waste integrated management system.

    Science.gov (United States)

    Wang, Wen; Xie, Li; Luo, Gang; Zhou, Qi; Lu, Qin

    2012-09-01

    Thermophilic co-fermentation of cassava stillage (CS) and cassava excess sludge (CES) were investigated for hydrogen and methane production. The highest hydrogen yield (37.1 ml/g-total-VS added) was obtained at VS(CS)/VS(CES) of 7:1, 17% higher than that with CS digestion alone. The CES recycle enhanced the substrate utilization and improved the buffer capacity. Further increase the CES fraction led to changed VFA distribution and more hydrogen consumption. FISH analysis revealed that both hydrogen producing bacteria and hydrogen consuming bacteria were enriched after CES recycled, and the acetobacteria percentage increased to 12.4% at VS(CS)/VS(CES) of 6:2. Relatively high efficient and stable hydrogen production was observed at VS(CS)/VS(CES) of 5:3 without pH adjusted and any pretreatment. The highest total energy yield, the highest COD and VS degradation were obtained at VS(CS)/VS(CES) of 7:1. GFC analysis indicated that the hydrolysis behavior was significantly improved by CES recycle at both hydrogen and methane production phase. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Digestion with initial thermophilic hydrolysis step for sanitation and enhanced methane extraction in wastewater treatment plants; Roetning med inledande termofilt hydrolyssteg foer hygienisering och utoekad metanutvinning paa avloppsreningsverk

    Energy Technology Data Exchange (ETDEWEB)

    Persson, Emelie; Ossiansson, Elin [BioMil AB, Lund (Sweden); Carlsson, My; Uldal, Martina; Johannesson, Sofia [AnoxKaldnes AB, Lund (Sweden)

    2012-02-15

    Thermophilic (55 deg) pre-hydrolysis has been shown to improve methane yield, organics reduction and/or treatment capacity when applied to anaerobic digestion (Persson m. fl. 2010). The method has also proven to kill off pathogens, making it an interesting hygienisation alternative to pasteurisation. The Swedish Environmental Protection Agency has opened up for the possibility to validate new methods for hygienisation, if the pathogen reduction can be proven to be efficient enough. Thermophilic pre-hydrolysis has several possible advantages to pasteurization; e. g. district heating of lower temperature can be used, the stability of the process may increase, as well as the efficiency and extent of the digestion process. The objective of this study is to evaluate the effect of thermophilic pre-hydrolysis on anaerobic digestion (AD) of sewage sludge with respect to: 1. Biogas/methane production and solids reduction. 2. Correlations between substrate properties, process conditions and effect on the AD process. 3. Pathogen reduction efficiency. 4. Operational consequences. Laboratory trials in continuous and batch mode were conducted on sewage sludge from four Swedish wastewater treatment plants. In the trials thermophilic pre-hydrolysis with consecutive mesophilic AD was compared to conventional one-step mesophilic AD, as well as pre-pasteurisation with consecutive AD. For all the tested sludge samples the reduction of TS and VS increased as a result of thermophilic pre-hydrolysis prior to mesophilic AD. The results with respect to methane yield were not as straightforward. Increased production of biogas was achieved in pilot scale, but the methane production did not improve. In the laboratory trials the effect on methane production varied from -8 % till +18 % for the sludge samples tested. The most positive results were achieved in the test that had the highest organic load and that was fed with a sludge that was low in fat and high in carbohydrates, compared to the

  13. Characterization of thermophilic fungal community associated with pile fermentation of Pu-erh tea.

    Science.gov (United States)

    Zhang, Wei; Yang, Ruijuan; Fang, Wenjun; Yan, Liang; Lu, Jun; Sheng, Jun; Lv, Jie

    2016-06-16

    This study aimed to characterize the thermophilic fungi in pile-fermentation process of Pu-erh tea. Physicochemical analyses showed that the high temperature and low pH provided optimal conditions for propagation of fungi. A number of fungi, including Blastobotrys adeninivorans, Thermomyces lanuginosus, Rasamsonia emersonii, Aspergillus fumigatus, Rhizomucor pusillus, Rasamsonia byssochlamydoides, Rasamsonia cylindrospora, Aspergillus tubingensis, Aspergillus niger, Candida tropicalis and Fusarium graminearum were isolated as thermophilic fungi under combination of high temperature and acid culture conditions from Pu-erh tea pile-fermentation. The fungal communities were analyzed by PCR-DGGE. Results revealed that those fungi are closely related to Debaryomyces hansenii, Cladosporium cladosporioides, A. tubingensis, R. emersonii, R. pusillus, A. fumigatus and A. niger, and the last four presented as dominant species in the pile process. These four preponderant thermophilic fungi reached the order of magnitude of 10(7), 10(7), 10(7) and 10(6)copies/g dry tea, respectively, measured by real-time quantitative PCR (q-PCR). The results indicate that the thermophilic fungi play an important role in Pu-erh tea pile fermentation. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Acidulocompost, a food waste compost with thermophilic lactic acid fermentation: its effects on potato production and weed growth

    OpenAIRE

    Naomi Asagi; Keisuke Minamide; Toru Uno; Masanori Saito; Toyoaki Ito

    2016-01-01

    Acidulocomposting recycles food wastes by means of thermophilic lactic acid fermentation. This process can decrease ammonia volatilization and odor emission during processing and produce compost with high nitrogen (N) content. To compare the yield of potatoes (Solanum tuberosum L. ‘Dansyakuimo’) and the suppression of weeds with acidulocompost (AC) and those with conventional composts and inorganic fertilizer (IF), we conducted field experiments in Miyagi Prefecture, northeastern Japan. Potat...

  15. The cellulase activity of an extreme thermophile

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, J A [Meat Industry Research Inst. of New Zealand, Hamilton (New Zealand); Morgan, H W; Daniel, R M [Waikato Univ., Hamilton (New Zealand). Microbial Biochemistry and Biotechnology Unit

    1991-05-01

    The carboxymethylcellulase activity concentrated from the extremely thermophilic anaerobe H173 was found to have a pH optimum of 6.5-7.0. The enzyme activity was stabilised by the addition of dithiothreitol and CaCl{sub 2}.2H{sub 2}O and was very stable at 80deg C, retaining 77% of the inital activity after 120 min incubation. At 90deg C however, 50% activity remained after 9 min and after 120 min only 3% of the initial activity remained. With the enzyme dissolved in buffer, glucose and cellobiose were formed from the hydrolysis of Avicel. In culture medium the Avicel-solubilising activity was insensitive to the presence of up to 50 mM glucose and showed linear glucose accumulation over a period of days at 70deg C. HPLC analysis established that glucose was the major end-product of hydrolysis in the culture broths. (orig.).

  16. Thermophilic ethanol fermentation from lignocellulose hydrolysate by genetically engineered Moorella thermoacetica.

    Science.gov (United States)

    Rahayu, Farida; Kawai, Yuto; Iwasaki, Yuki; Yoshida, Koichiro; Kita, Akihisa; Tajima, Takahisa; Kato, Junichi; Murakami, Katsuji; Hoshino, Tamotsu; Nakashimada, Yutaka

    2017-12-01

    A transformant of Moorella thermoacetica was constructed for thermophilic ethanol production from lignocellulosic biomass by deleting two phosphotransacetylase genes, pdul1 and pdul2, and introducing the native aldehyde dehydrogenase gene (aldh) controlled by the promoter from glyceraldehyde-3-phosphate dehydrogenase. The transformant showed tolerance to 540mM and fermented sugars including fructose, glucose, galactose and xylose to mainly ethanol. In a mixed-sugar medium of glucose and xylose, all of the sugars were consumed to produce ethanol at the yield of 1.9mol/mol-sugar. The transformant successfully fermented sugars in hydrolysate prepared through the acid hydrolysis of lignocellulose to ethanol, suggesting that this transformant can be used to ferment the sugars in lignocellulosic biomass for ethanol production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Hydrogenomics of the extremely thermophilic bacterium Caldicellulosiruptor saccharolyticus

    NARCIS (Netherlands)

    Werken, van de H.J.G.; Verhaart, M.R.A.; Vanfossen, A.L.; Willquist, K.; Lewis, D.L.; Nichols, J.D.; Goorissen, H.P.; Mongodin, E.F.; Nelson, K.E.; Niel, van E.W.J.; Stams, A.J.M.; Ward, D.E.; Vos, de W.M.; Oost, van der J.; Kelly, R.M.; Kengen, S.W.M.

    2008-01-01

    Caldicellulosiruptor saccharolyticus is an extremely thermophilic, gram-positive anaerobe which ferments cellulose-, hemicellulose- and pectin-containing biomass to acetate, CO(2), and hydrogen. Its broad substrate range, high hydrogen-producing capacity, and ability to coutilize glucose and xylose

  18. A new approach for concurrently improving performance of South Korean food waste valorization and renewable energy recovery via dry anaerobic digestion under mesophilic and thermophilic conditions.

    Science.gov (United States)

    Nguyen, Dinh Duc; Yeop, Jeong Seong; Choi, Jaehoon; Kim, Sungsu; Chang, Soon Woong; Jeon, Byong-Hun; Guo, Wenshan; Ngo, Huu Hao

    2017-08-01

    Dry semicontinuous anaerobic digestion (AD) of South Korean food waste (FW) under four solid loading rates (SLRs) (2.30-9.21kg total solids (TS)/m 3 day) and at a fixed TS content was compared between two digesters, one each under mesophilic and thermophilic conditions. Biogas production and organic matter reduction in both digesters followed similar trends, increasing with rising SLR. Inhibitor (intermediate products of the anaerobic fermentation process) effects on the digesters' performance were not observed under the studied conditions. In all cases tested, the digesters' best performance was achieved at the SLR of 9.21kg TS/m 3 day, with 74.02% and 80.98% reduction of volatile solids (VS), 0.87 and 0.90m 3 biogas/kg VS removed , and 0.65 (65% CH 4 ) and 0.73 (60.02% CH 4 ) m 3 biogas/kg VS fed , under mesophilic and thermophilic conditions, respectively. Thermophilic dry AD is recommended for FW treatment in South Korea because it is more efficient and has higher energy recovery potential when compared to mesophilic dry AD. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Thermophilic anaerobic acetate-utilizing methanogens and their metabolism

    DEFF Research Database (Denmark)

    Mladenovska, Zuzana

    Six strains of thermophilic anaerobic acetate-utilizing methanogens were isolated from different full-scale thermophilic biogas plants in China and Denmark. The strain isolated from the Chinese biogas plant was designated KN-6P and the isolates from the Danish full-scale biogas plants were......, utilizing the substrates acetate, methanol and methylamines but not hydrogen/carbon dioxide. Strain Methanosarcina sp. SO-2P was able to grow mixotrophically on methanol and hydrogen/carbon dioxide with methane formation from hydrogen and carbon dioxide occurring after methanol depletion. All six...... designated HG-1P, LVG-4P R1-1P, SO-2P and V-1P. The isolates were characterized morphologically and physiologically, and their immunological and phylogenetic relatedness to already known isolated strains were established. All isolated strains were identified as organisms belonging to genus Methanosarcina...

  20. Macroscopic mass and energy balance of a pilot plant anaerobic bioreactor operated under thermophilic conditions.

    Science.gov (United States)

    Espinosa-Solares, Teodoro; Bombardiere, John; Chatfield, Mark; Domaschko, Max; Easter, Michael; Stafford, David A; Castillo-Angeles, Saul; Castellanos-Hernandez, Nehemias

    2006-01-01

    Intensive poultry production generates over 100,000 t of litter annually in West Virginia and 9 x 10(6) t nationwide. Current available technological alternatives based on thermophilic anaerobic digestion for residuals treatment are diverse. A modification of the typical continuous stirred tank reactor is a promising process being relatively stable and owing to its capability to manage considerable amounts of residuals at low operational cost. A 40-m3 pilot plant digester was used for performance evaluation considering energy input and methane production. Results suggest some changes to the pilot plant configuration are necessary to reduce power consumption although maximizing biodigester performance.

  1. Structural adaptation of the subunit interface of oligomeric thermophilic and hyperthermophilic enzymes.

    Science.gov (United States)

    Maugini, Elisa; Tronelli, Daniele; Bossa, Francesco; Pascarella, Stefano

    2009-04-01

    Enzymes from thermophilic and, particularly, from hyperthermophilic organisms are surprisingly stable. Understanding of the molecular origin of protein thermostability and thermoactivity attracted the interest of many scientist both for the perspective comprehension of the principles of protein structure and for the possible biotechnological applications through application of protein engineering. Comparative studies at sequence and structure levels were aimed at detecting significant differences of structural parameters related to protein stability between thermophilic and hyperhermophilic structures and their mesophilic homologs. Comparative studies were useful in the identification of a few recurrent themes which the evolution utilized in different combinations in different protein families. These studies were mostly carried out at the monomer level. However, maintenance of a proper quaternary structure is an essential prerequisite for a functional macromolecule. At the environmental temperatures experienced typically by hyper- and thermophiles, the subunit interactions mediated by the interface must be sufficiently stable. Our analysis was therefore aimed at the identification of the molecular strategies adopted by evolution to enhance interface thermostability of oligomeric enzymes. The variation of several structural properties related to protein stability were tested at the subunit interfaces of thermophilic and hyperthermophilic oligomers. The differences of the interface structural features observed between the hyperthermophilic and thermophilic enzymes were compared with the differences of the same properties calculated from pairwise comparisons of oligomeric mesophilic proteins contained in a reference dataset. The significance of the observed differences of structural properties was measured by a t-test. Ion pairs and hydrogen bonds do not vary significantly while hydrophobic contact area increases specially in hyperthermophilic interfaces. Interface

  2. Dispersal of thermophilic Desulfotomaculum endospores into Baltic Sea sediments over thousands of years

    DEFF Research Database (Denmark)

    Rezende, Julia Rosa de; Kjeldsen, Kasper Urup; Hubert, Casey RJ

    2013-01-01

    S rRNA and of the dissimilatory (bi)sulfite reductase (dsrAB) genes within the endospore-forming SRB genus Desulfotomaculum. The thermophilic Desulfotomaculum community in Aarhus Bay sediments consisted of at least 23 species-level 16S rRNA sequence phylotypes. In two cases, pairs of identical 16S r......RNA and dsrAB sequences in Arctic surface sediment 3000km away showed that the same phylotypes are present in both locations. Radiotracer-enhanced most probable number analysis revealed that the abundance of endospores of thermophilic SRB in Aarhus Bay sediment was ca. 104 per cm3 at the surface and decreased...... in water masses preceding sedimentation. The sources of these thermophiles remain enigmatic, but at least one source may be common to both Aarhus Bay and Arctic sediments....

  3. Thermophilic versus Mesophilic Anaerobic Digestion of Sewage Sludge: A Comparative Review

    Directory of Open Access Journals (Sweden)

    Getachew D. Gebreeyessus

    2016-06-01

    Full Text Available During advanced biological wastewater treatment, a huge amount of sludge is produced as a by-product of the treatment process. Hence, reuse and recovery of resources and energy from the sludge is a big technological challenge. The processing of sludge produced by Wastewater Treatment Plants (WWTPs is massive, which takes up a big part of the overall operational costs. In this regard, anaerobic digestion (AD of sewage sludge continues to be an attractive option to produce biogas that could contribute to the wastewater management cost reduction and foster the sustainability of those WWTPs. At the same time, AD reduces sludge amounts and that again contributes to the reduction of the sludge disposal costs. However, sludge volume minimization remains, a challenge thus improvement of dewatering efficiency is an inevitable part of WWTP operation. As a result, AD parameters could have significant impact on sludge properties. One of the most important operational parameters influencing the AD process is temperature. Consequently, the thermophilic and the mesophilic modes of sludge AD are compared for their pros and cons by many researchers. However, most comparisons are more focused on biogas yield, process speed and stability. Regarding the biogas yield, thermophilic sludge AD is preferred over the mesophilic one because of its faster biochemical reaction rate. Equally important but not studied sufficiently until now was the influence of temperature on the digestate quality, which is expressed mainly by the sludge dewateringability, and the reject water quality (chemical oxygen demand, ammonia nitrogen, and pH. In the field of comparison of thermophilic and mesophilic digestion process, few and often inconclusive research, unfortunately, has been published so far. Hence, recommendations for optimized technologies have not yet been done. The review presented provides a comparison of existing sludge AD technologies and the gaps that need to be filled so

  4. Thermophilic versus Mesophilic Anaerobic Digestion of Sewage Sludge: A Comparative Review

    Science.gov (United States)

    Gebreeyessus, Getachew D.; Jenicek, Pavel

    2016-01-01

    During advanced biological wastewater treatment, a huge amount of sludge is produced as a by-product of the treatment process. Hence, reuse and recovery of resources and energy from the sludge is a big technological challenge. The processing of sludge produced by Wastewater Treatment Plants (WWTPs) is massive, which takes up a big part of the overall operational costs. In this regard, anaerobic digestion (AD) of sewage sludge continues to be an attractive option to produce biogas that could contribute to the wastewater management cost reduction and foster the sustainability of those WWTPs. At the same time, AD reduces sludge amounts and that again contributes to the reduction of the sludge disposal costs. However, sludge volume minimization remains, a challenge thus improvement of dewatering efficiency is an inevitable part of WWTP operation. As a result, AD parameters could have significant impact on sludge properties. One of the most important operational parameters influencing the AD process is temperature. Consequently, the thermophilic and the mesophilic modes of sludge AD are compared for their pros and cons by many researchers. However, most comparisons are more focused on biogas yield, process speed and stability. Regarding the biogas yield, thermophilic sludge AD is preferred over the mesophilic one because of its faster biochemical reaction rate. Equally important but not studied sufficiently until now was the influence of temperature on the digestate quality, which is expressed mainly by the sludge dewateringability, and the reject water quality (chemical oxygen demand, ammonia nitrogen, and pH). In the field of comparison of thermophilic and mesophilic digestion process, few and often inconclusive research, unfortunately, has been published so far. Hence, recommendations for optimized technologies have not yet been done. The review presented provides a comparison of existing sludge AD technologies and the gaps that need to be filled so as to optimize

  5. Deep Conversion of Carbon Monoxide to Hydrogen and Formation of Acetate by the Anaerobic Thermophile Carboxydothermus hydrogenoformans

    OpenAIRE

    Henstra, Anne M.; Stams, Alfons J. M.

    2011-01-01

    Carboxydothermus hydrogenoformans is a thermophilic strictly anaerobic bacterium that catalyses the water gas shift reaction, the conversion of carbon monoxide with water to molecular hydrogen and carbon dioxide. The thermodynamically favorable growth temperature, compared to existing industrial catalytic processes, makes this organism an interesting alternative for production of cheap hydrogen gas suitable to fuel CO-sensitive fuel cells in a future hydrogen economy, provided sufficiently lo...

  6. Increased saccharification of kallar grass using ultrafiltrated enzyme from sporrotrichum thermophile

    International Nuclear Information System (INIS)

    Latif, F.; Rajoka, M.I.; Malik, K.A.

    1991-01-01

    The local wild type strain of sporotrichum thermophile when grown on untreated lingo cellulose was found to produce a greater level of B-glucosidase component along with other cellulase/xylanase components than most of the reported wild type potent strains. Culture filtrate obtained, when grown on 4% leptochloa fusca (kallar grass) was used as such and after concentration by ultrafiltration technique for saccharification purpose. Concentrated enzymes titre was increased to 1.2 and 4.0 U/ml for Fp-ase and B-glucosidase, respectively. There were losses in the enzyme titre obtained through ultrafiltration possibly due to adsorption on to the ultrafiltration membrane. Enzyme preparations used, saccharifide 5% kallar grass to 70, 55, 75 and 60% (theoretical basis) from cellulases of S. thermophile concentrate, dilute, T. reesei alone and in supplementation with B-glucosidase from A. niger, respectively. Analysis by HPLC revealed slightly higher glucose yield from S. thermophile enzyme preparations, whereas higher level of xylose was attained from T. reesei preparations. Rest of the sugars pooled as Oligo-sugars were found in almost similar concentrations. (author)

  7. Renewable Bio-Solar Hydrogen Production: The Second Generation (Part B)

    Science.gov (United States)

    2015-03-20

    SUBJECT TERMS Biohydrogen, biofuels, cyanobacteria, photosynthesis, fermentation , transcription profiling, metabolic engineering, TCA cycle...transcription regulators, including RbcR, Fur, and ChlR, were identified and characterized, and a global model of the transcription network was...enhance hydrogen production. These data have recently been analyzed to produce a global transcription network model for this cyanobacterium [17]. At

  8. Extremely thermophilic microorganisms for biomass conversion: status and prospects.

    Science.gov (United States)

    Blumer-Schuette, Sara E; Kataeva, Irina; Westpheling, Janet; Adams, Michael Ww; Kelly, Robert M

    2008-06-01

    Many microorganisms that grow at elevated temperatures are able to utilize a variety of carbohydrates pertinent to the conversion of lignocellulosic biomass to bioenergy. The range of substrates utilized depends on growth temperature optimum and biotope. Hyperthermophilic marine archaea (T(opt)>or=80 degrees C) utilize alpha- and beta-linked glucans, such as starch, barley glucan, laminarin, and chitin, while hyperthermophilic marine bacteria (T(opt)>or=80 degrees C) utilize the same glucans as well as hemicellulose, such as xylans and mannans. However, none of these organisms are able to efficiently utilize crystalline cellulose. Among the thermophiles, this ability is limited to a few terrestrial bacteria with upper temperature limits for growth near 75 degrees C. Deconstruction of crystalline cellulose by these extreme thermophiles is achieved by 'free' primary cellulases, which are distinct from those typically associated with large multi-enzyme complexes known as cellulosomes. These primary cellulases also differ from the endoglucanases (referred to here as 'secondary cellulases') reported from marine hyperthermophiles that show only weak activity toward cellulose. Many extremely thermophilic enzymes implicated in the deconstruction of lignocellulose can be identified in genome sequences, and many more promising biocatalysts probably remain annotated as 'hypothetical proteins'. Characterization of these enzymes will require intensive effort but is likely to generate new opportunities for the use of renewable resources as biofuels.

  9. Optimization of separate hydrogen and methane production from cassava wastewater using two-stage upflow anaerobic sludge blanket reactor (UASB) system under thermophilic operation.

    Science.gov (United States)

    Intanoo, Patcharee; Rangsanvigit, Pramoch; Malakul, Pomthong; Chavadej, Sumaeth

    2014-12-01

    The objective of this study was to investigate the separate hydrogen and methane productions from cassava wastewater by using a two-stage upflow anaerobic sludge blanket (UASB) system under thermophilic operation. Recycle ratio of the effluent from methane bioreactor-to-feed flow rate was fixed at 1:1 and pH of hydrogen UASB unit was maintained at 5.5. At optimum COD loading rate of 90 kg/m3 d based on the feed COD load and hydrogen UASB volume, the produced gas from the hydrogen UASB unit mainly contained H2 and CO2 which provided the maximum hydrogen yield (54.22 ml H2/g COD applied) and specific hydrogen production rate (197.17 ml/g MLVSSd). At the same optimum COD loading rate, the produced gas from the methane UASB unit mainly contained CH4 and CO2 without H2 which were also consistent with the maximum methane yield (164.87 ml CH4/g COD applied) and specific methane production rate (356.31 ml CH4/g MLVSSd). The recycling operation minimized the use of NaOH for pH control in hydrogen UASB unit. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Screening of Thermophilic Bacteria Produce Xylanase from Sapan Sungai Aro Hot Spring South Solok

    Science.gov (United States)

    Irdawati, I.; Syamsuardi, S.; Agustien, A.; Rilda, Y.

    2018-04-01

    xylanase is one of the enzymes with great prospects as hemicellulose hydrolyzing enzyme. Global annual market demand for this enzyme reach US 200 million. This enzyme catalyzes the xylan (hemicellulose) reactions breaking into xilooligosakarida and xylose. Xylanase can be applied to various industrial sectors such as bread, sugar xylose, biofuels, especially in bleaching paper (bleaching) pulp. Xylanase Isable to replace conventional chemical bleaching using chlorine that is not friendly for the environment. Currently xylanase production is extracted from the thermophilic bacteria for enzyme stability at high temperatures that are suitable for industrial applications. Thermophilic bacteria can be isolated from a hot spring, one of the which is a source of Sapan Sungai Aro Hot Spring, located in the district South Solok. The aim of this study was to select and identification of thermophilic bacteria can produce xylanase.This roomates is a descriptive study, which was Carried out in the Laboratory of Microbiology, Mathematic and Science Faculty of Padang State University, and Laboratory of Bacteriology, BasoVeterinary Research Center. The research procedure consisted of the preparation and sterilization of materials and tools, medium manufacturing, regeneration, selection and identification. Selection is performed by using a semiquantitative screening plate that contains xylan substrate. Identification is based on microscopic and biochemical characteristics until the genus level.Selection results Showed 12 out of 16 isolates had xilanolitik activity, with the highest activity is SSA2 with xilanolitik index of 0.74. The top five index producehigestxilanolitik isolates that are SSA2, SSA3 and SSA4 identified as Bacillus sp. 1., and SSAS6 and SSA7 is Bacillus sp. 2.

  11. Ethanol production from wet-exploded wheat straw hydrolysate by thermophilic anaerobic bacterium Thermoanaerobacter BG1L1 in a continuous immobilized reactor

    DEFF Research Database (Denmark)

    Georgieva, Tania I.; Mikkelsen, Marie Just; Ahring, Birgitte Kiær

    2008-01-01

    was not detoxified, ethanol yield in a range of 0.39-0.42 g/g was obtained. Overall, sugar efficiency to ethanol was 68-76%. The reactor was operated continuously for approximately 143 days, and no contamination was seen without the use of any agent for preventing bacterial infections. The tested microorganism has......Thermophilic ethanol fermentation of wet-exploded wheat straw hydrolysate was investigated in a continuous immobilized reactor system. The experiments were carried out in a lab-scale fluidized bed reactor (FBR) at 70C. Undetoxified wheat straw hydrolysate was used (3-12% dry matter), corresponding...... to sugar mixtures of glucose and xylose ranging from 12 to 41 g/l. The organism, thermophilic anaerobic bacterium Thermoanaerobacter BG1L1, exhibited significant resistance to high levels of acetic acid (up to 10 g/l) and other metabolic inhibitors present in the hydrolysate. Although the hydrolysate...

  12. Characterization of Probiotic Fermented Milk Prepared by Different Inoculation Size of Mesophilic and Thermophilic Lactic Acid Bacteria

    Directory of Open Access Journals (Sweden)

    Sara Nasiri Boosjin

    2016-10-01

    Full Text Available Background and Objectives: Importance of development of novel probiotic fermented milk and challenge made for its acceptability is well known. In this research, the impact of different inoculation sizes of yogurt and DL-type starter culture (mesophilic and thermophilic LAB on titratable acidity, viscosity, sensorial and microbial properties of fermented milk was investigated; and finally, probiotic Langfil was produced.Materials and Methods: Fermented milk produced by 1, 2 and 3% v v-1 inocula consisting thermophilic: mesophilic starter cultures 10:90 (Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. lactis biovar. diacetylactis and Leuconostoc mesenteroides subsp. cremoris. Streptococcus thermophilus and Lactobacillus delbrueckii subsp. Bulgaricus were analyzed for determination of titratable acidity, viscosity, viability of mesophilic starter cultures and sensory properties on days 5, 10, and 15 of storage at 4°C. Then, the most suitable treatments were selected for the producing probiotic Langfil, containing probiotic starter culture (2% v v-1 inoculums with equal ratio of Lactobacillus acidophilus and Bifidobacterium bifidum. Lactococcus lactis and L. cremoris were counted on M17 agar, while Leuconostoc and Lactobacillus were counted aerobically on tomato juice agar and MRS bile agar, respectively. Bifidobacterium was cultured anaerobically on MRS bile agar. Sensory evaluation was carried out by ten trained panelists, based on a nine-point hedonic scale during the cold storage.Results and Conclusion: According to results, the best organoleptic properties were achieved in the product prepared with 2% the mesophilic and thermophilic starter cultures and 2% probiotic. This product had a high viscosity. An Iranian probiotic Langfil with desired properties was produced using the best treatment prepared.Conflict of interests: The authors declare no conflict of

  13. Application of thermophilic enzymes and water jet system to cassava pulp.

    Science.gov (United States)

    Chaikaew, Siriporn; Maeno, Yuka; Visessanguan, Wonnop; Ogura, Kota; Sugino, Gaku; Lee, Seung-Hwan; Ishikawa, Kazuhiko

    2012-12-01

    Co-production of fermentable sugars and nanofibrillated cellulose from cassava pulp was achieved by the combination of thermophilic enzymes (endoglucanase, β-glucosidase, and α-amylase) and a new atomization system (Star Burst System; SBS), which employs opposing water jets. The SBS represents a key technology for providing cellulose nanofibers and improving the enzymatic saccharification of cassava pulp. Depending on the enzymes used, the production of glucose from cassava pulp treated with the SBS was 1.2- to 2.5-fold higher than that from pulp not treated with the SBS. Nanofibrillated cellulose with the gel-like property in suspension was produced (yield was over 90%) by α-amylase treatment, which completely released trapped starch granules from the fibrous cell wall structure of cassava pulp pretreated with the SBS. The SBS provides an environmentally low-impact pretreatment system for processing biomass material into value-added products. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Methanomethylovorans thermophila sp. nov., a thermophilic, methylotrophic methanogen form an anaerobic reactor fed with methanol

    NARCIS (Netherlands)

    Jiang, B.; Parshina, S.N.; Doesburg, van W.C.J.; Lomans, B.P.; Stams, A.J.M.

    2005-01-01

    A novel thermophilic, obligately methylotrophic, methanogenic archaeon, strain L2FAWT, was isolated from a thermophilic laboratory-scale upflow anaerobic sludge blanket reactor fed with methanol as the carbon and energy source. Cells of strain L2FAWT were non-motile, irregular cocci, 0·7¿1·5 µm in

  15. Direct hydrogen production from dilute-acid pretreated sugarcane bagasse hydrolysate using the newly isolated Thermoanaerobacterium thermosaccharolyticum MJ1.

    Science.gov (United States)

    Hu, Bin-Bin; Zhu, Ming-Jun

    2017-05-03

    Energy shortage and environmental pollution are two severe global problems, and biological hydrogen production from lignocellulose shows great potential as a promising alternative biofuel to replace the fossil fuels. Currently, most studies on hydrogen production from lignocellulose concentrate on cellulolytic microbe, pretreatment method, process optimization and development of new raw materials. Due to no effective approaches to relieve the inhibiting effect of inhibitors, the acid pretreated lignocellulose hydrolysate was directly discarded and caused environmental problems, suggesting that isolation of inhibitor-tolerant strains may facilitate the utilization of acid pretreated lignocellulose hydrolysate. Thermophilic bacteria for producing hydrogen from various kinds of sugars were screened, and the new strain named MJ1 was isolated from paper sludge, with 99% identity to Thermoanaerobacterium thermosaccharolyticum by 16S rRNA gene analysis. The hydrogen yields of 11.18, 4.25 and 2.15 mol-H 2 /mol sugar can be reached at an initial concentration of 5 g/L cellobiose, glucose and xylose, respectively. The main metabolites were acetate and butyrate. More important, MJ1 had an excellent tolerance to inhibitors of dilute-acid (1%, g/v) pretreated sugarcane bagasse hydrolysate (DAPSBH) and could efficiently utilize DAPSBH for hydrogen production without detoxication, with a production higher than that of pure sugars. The hydrogen could be quickly produced with the maximum hydrogen production reached at 24 h. The hydrogen production reached 39.64, 105.42, 111.75 and 110.44 mM at 20, 40, 60 and 80% of DAPSBH, respectively. Supplementation of CaCO 3 enhanced the hydrogen production by 21.32% versus the control. These results demonstrate that MJ1 could directly utilize DAPSBH for biohydrogen production without detoxication and can serve as an excellent candidate for industrialization of hydrogen production from DAPSBH. The results also suggest that isolating unique

  16. Startup and stability of thermophilic anaerobic digestion of OFMSW

    KAUST Repository

    El-Fadel, Mutasem E.; Saikaly, Pascal; Ghanimeh, Sophia A.

    2013-01-01

    Anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) is promoted as an energy source and more recently as a greenhouse gas (GHG) mitigation measure. In this context, AD systems operating at thermophilic temperatures (55-60°C)-compared to mesophilic temperatures (35-40°C)-have the unique feature of producing hygienic soil conditioners with greater process efficiency, higher energy yield, and more GHG savings. Startup of AD systems is often constrained by the lack of acclimated seeds, leading to process instability and failure. The authors focus on strategies to startup thermophilic digesters treating OFMSW in the absence of acclimated seeds and examines constraints associated with process stability and ways to overcome them. Relevant gaps in the literature and future research needs are delineated. © 2013 Taylor & Francis Group, LLC.

  17. High production, purification, biochemical characterization and gene analysis of a novel catalase from the thermophilic bacterium Ureibacillus thermosphaericus FZSF03.

    Science.gov (United States)

    Jia, Xianbo; Lin, Xinjian; Tian, Yandan; Chen, Jichen; You, Minsheng

    2017-10-01

    A catalase-producing thermophilic bacterium, Ureibacillus thermosphaericus FZSF03, was isolated from high-temperature compost. Catalase production in this strain increased 31 times and reached 57,630U/mL after optimization in a shake flask, which might represent the highest catalase activity level among reported wild strains. This catalase was further purified and identified. The purified enzyme showed a specific activity of 219,360U/mg, higher than many other catalases. The molecular weight of this enzyme is 52kDa according to sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and the enzyme was identified as a monofunctional haeme catalase of Ureibacillus thermosphaericus by liquid chromatography-mass spectrometry (LC-MS)/MS. The optimal reaction temperature for this catalase was found to be 60°C. Stability was observed at 60°C and at a pH of 10.0, indicating the superiority of this enzyme at a high temperature and under alkaline conditions. Therefore, this catalase is a prospective candidate for industrial production and applications. The gene encoding this catalase is 1503bp. As the amino acid sequence shows low similarity with other catalases, we suggest that this is a novel monofunctional haeme catalase. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Kinetics of Butyrate, Acetate, and Hydrogen Metabolism in a Thermophilic, Anaerobic, Butyrate-Degrading Triculture

    OpenAIRE

    Ahring, Birgitte K.; Westermann, Peter

    1987-01-01

    Kinetics of butyrate, acetate, and hydrogen metabolism were determined with butyrate-limited, chemostat-grown tricultures of a thermophilic butyrate-utilizing bacterium together with Methanobacterium thermoautotrophicum and the TAM organism, a thermophilic acetate-utilizing methanogenic rod. Kinetic parameters were determined from progress curves fitted to the integrated form of the Michaelis-Menten equation. The apparent half-saturation constants, Km, for butyrate, acetate, and dissolved hyd...

  19. Cellulose- and xylan-degrading thermophilic anaerobic bacteria from biocompost.

    Science.gov (United States)

    Sizova, M V; Izquierdo, J A; Panikov, N S; Lynd, L R

    2011-04-01

    Nine thermophilic cellulolytic clostridial isolates and four other noncellulolytic bacterial isolates were isolated from self-heated biocompost via preliminary enrichment culture on microcrystalline cellulose. All cellulolytic isolates grew vigorously on cellulose, with the formation of either ethanol and acetate or acetate and formate as principal fermentation products as well as lactate and glycerol as minor products. In addition, two out of nine cellulolytic strains were able to utilize xylan and pretreated wood with roughly the same efficiency as for cellulose. The major products of xylan fermentation were acetate and formate, with minor contributions of lactate and ethanol. Phylogenetic analyses of 16S rRNA and glycosyl hydrolase family 48 (GH48) gene sequences revealed that two xylan-utilizing isolates were related to a Clostridium clariflavum strain and represent a distinct novel branch within the GH48 family. Both isolates possessed high cellulase and xylanase activity induced independently by either cellulose or xylan. Enzymatic activity decayed after growth cessation, with more-rapid disappearance of cellulase activity than of xylanase activity. A mixture of xylan and cellulose was utilized simultaneously, with a significant synergistic effect observed as a reduction of lag phase in cellulose degradation.

  20. Production of high concentration of L-lactic acid from cellobiose by thermophilic Bacillus coagulans WCP10-4.

    Science.gov (United States)

    Ong, Shufen Angeline; Ng, Zhi Jian; Wu, Jin Chuan

    2016-07-01

    Thermophilic Bacillus coagulans WCP10-4 is found to be able to convert cellobiose to optically pure L-lactic acid. Its β-glucosidase activity is detected in whole cells (7.3 U/g dry cells) but not in culture medium, indicating the intracellular location of the enzyme. Its β-glucosidase activity is observed only when cultured using cellobiose as the sole carbon source, indicating that the expression of this enzyme is tightly regulated in cells. The enzyme is most active at 50 °C and pH 7.0. The supplement of external β-glucosidase during fermentation of cellobiose (106 g/l) by B. coagulans WCP10-4 increased the fermentation time from 21 to 23 h and decreased the lactic acid yield from 96.1 to 92.9 % compared to the control without β-glucosidase supplementation. B. coagulans WCP10-4 converted 200 g/l of cellobiose to 196.3 g/l of L-lactic acid at a yield of 97.8 % and a productivity of 7.01 g/l/h. This result shows that B. coagulans WCP10-4 is a highly efficient strain for converting cellobiose to L-lactic acid without the need of supplementing external β-glucosidases.

  1. Draft Genome Sequence of Aeribacillus pallidus Strain 8m3, a Thermophilic Hydrocarbon-Oxidizing Bacterium Isolated from the Dagang Oil Field (China)

    OpenAIRE

    Poltaraus, Andrey B.; Sokolova, Diyana S.; Grouzdev, Denis S.; Ivanov, Timophey M.; Malakho, Sophia G.; Korshunova, Alena V.; Rozanov, Aleksey S.; Tourova, Tatiyana P.; Nazina, Tamara N.

    2016-01-01

    The draft genome sequence of Aeribacillus pallidus strain 8m3, a thermophilic aerobic oil-oxidizing bacterium isolated from production water from the Dagang high-temperature oil field, China, is presented here. The genome is annotated to provide insights into the genomic and phenotypic diversity of the genus Aeribacillus.

  2. Caldanaerobacter uzonensis sp. nov., an anaerobic, thermophilic, heterotrophic bacterium isolated from a hot spring.

    Science.gov (United States)

    Kozina, Irina V; Kublanov, Ilya V; Kolganova, Tatyana V; Chernyh, Nikolai A; Bonch-Osmolovskaya, Elizaveta A

    2010-06-01

    An anaerobic thermophilic bacterium, strain K67(T), was isolated from a terrestrial hot spring of Uzon Caldera, Kamchatka Peninsula. Analysis of the 16S rRNA gene sequence revealed that the novel isolate belongs to the genus Caldanaerobacter, with 95 % 16S rRNA gene sequence similarity to Caldanaerobacter subterraneus subsp. subterraneus SEBR 7858(T), suggesting that it represents a novel species of the genus Caldanaerobacter. Strain K67(T) was characterized as an obligate anaerobe, a thermophile (growth at 50-75 degrees capital ES, Cyrillic; optimum 68-70 degrees C), a neutrophile (growth at pH(25 degrees C) 4.8-8.0; optimum pH(25 degrees C) 6.8) and an obligate organotroph (growth by fermentation of various sugars, peptides and polysaccharides). Major fermentation products were acetate, H2 and CO2; ethanol, lactate and l-alanine were formed in smaller amounts. Thiosulfate stimulated growth and was reduced to hydrogen sulfide. Nitrate, sulfate, sulfite and elemental sulfur were not reduced and did not stimulate growth. Thus, according to the strain's phylogenetic position and phenotypic novelties (lower upper limit of temperature range for growth, the ability to grow on arabinose, the inability to reduce elemental sulfur and the formation of alanine as a minor fermentation product), the novel species Caldanaerobacter uzonensis sp. nov. is proposed, with the type strain K67(T) (=DSM 18923(T) =VKM capital VE, Cyrillic-2408(T)).

  3. Valorization of crude glycerol from biodiesel production

    Directory of Open Access Journals (Sweden)

    Konstantinović Sandra S.

    2016-01-01

    Full Text Available The increased production of biodiesel as an alternative fuel involves the simultaneous growth in production of crude glycerol as its main by-product. Therefore, the feasibility and sustainability of biodiesel production requires the effective utilization of crude glycerol. This review describes various uses of crude glycerol as a potential green solvent for chemical reactions, a starting raw material for chemical and biochemical conversions into value-added chemicals, a substrate or co-substrate in microbial fermentations for synthesis of valuable chemicals and production of biogas and biohydrogen as well as a feedstuff for animal feed. A special attention is paid to various uses of crude glycerol in biodiesel production. [Projekat Ministarstva nauke Republike Srbije, br. III 45001

  4. Silver Sulfidation in Thermophilic Anaerobic Digesters and Effects on Antibiotic Resistance Genes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bojeong; Miller, Jennifer H.; Monsegue, Niven; Levard, Clément; Hong, Yanjuan; Hull, Matthew S.; Murayama, Mitsuhiro; Brown, Gordon E.; Vikesland, Peter J.; Knocke, William R.; Pruden, Amy; Hochella, Michael F.

    2015-12-15

    Physical and chemical transformations and biological responses of silver nanoparticles (AgNPs) in wastewater treatment systems are of particular interest because of the extensive existing and continually growing uses of AgNPs in consumer products. In this study, we investigated the transformation of AgNPs and AgNO3 during thermophilic anaerobic digestion and effects on selection or transfer of antibiotic resistance genes (ARGs). Ag2S-NPs, sulfidation products of both AgNPs and AgNO3, were recovered from raw and digested sludges and were analyzed by analytical transmission electron microscopy (TEM) and X-ray absorption spectroscopy (XAS). TEM and XAS revealed rapid (≤20 min) Ag sulfidation for both Ag treatments. Once transformed, Ag2S-NPs (as individual NPs or an NP aggregate) persisted for the duration of the batch digestion. The digestion process produced Ag2S-NPs that were strongly associated with sludge organics and/or other inorganic precipitates. Ag treatments (up to 1,000 mg Ag/kg) did not have an impact on the performance of thermophilic anaerobic digesters or ARG response, as indicated by quantitative polymerase chain reaction measurements of sul1, tet(W), and tet(O) and also intI1, an indicator of horizontal gene transfer of ARGs. Thus, rapid Ag sulfidation and stabilization with organics effectively sequester Ag and prevent biological interactions with the digester microbial community that could induce horizontal gene transfer or adversely impact digester performance through antimicrobial activity. This finding suggests that sulfide-rich anaerobic environments, such as digesters, likely have a high buffer capacity to mitigate the biological effects of AgNPs.

  5. Production and properties of two types of xylanases from alkalophilic thermophilic Bacillus spp

    Energy Technology Data Exchange (ETDEWEB)

    Okazaki, W; Akahoshi, R; Akiba, T; Horikoshi, K

    1984-05-01

    Four strains (W1, W2, W3, and W4) of alkalophilic thermophilic bacteria which produced xylanase were isolated from soils. They were aerobic, spore-forming. Gram-positive, and rod-shaped bacteria and hence identified as the genus Bacillus. The optimal temperatures for growth of the four strains were between 45/sup 0/C and 50/sup 0/C and pH optima were between 9.0 and 10.0. No growth occurred below pH 7.0 or above 55/sup 0/C. The four strains produced xylanases in medium containing xylan or xylose under these conditions. The optimal pH and temperature for activities of the four xylanases ranged from 6.0 to 7.0 and from 65/sup 0/C to 70/sup 0/C, respectively. The four xylanases were stable in the wide pH range from 4.5 to 10.5 at 45/sup 0/C for 1 h. All xylanases split xylan to yield xylose and xylobiose.

  6. Improved lignocellulose conversion to biofuels with thermophilic bacteria and thermostable enzymes.

    Science.gov (United States)

    Bhalla, Aditya; Bansal, Namita; Kumar, Sudhir; Bischoff, Kenneth M; Sani, Rajesh K

    2013-01-01

    Second-generation feedstock, especially nonfood lignocellulosic biomass is a potential source for biofuel production. Cost-intensive physical, chemical, biological pretreatment operations and slow enzymatic hydrolysis make the overall process of lignocellulosic conversion into biofuels less economical than available fossil fuels. Lignocellulose conversions carried out at ≤ 50 °C have several limitations. Therefore, this review focuses on the importance of thermophilic bacteria and thermostable enzymes to overcome the limitations of existing lignocellulosic biomass conversion processes. The influence of high temperatures on various existing lignocellulose conversion processes and those that are under development, including separate hydrolysis and fermentation, simultaneous saccharification and fermentation, and extremophilic consolidated bioprocess are also discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. DSMZ 24726 for second generation bioethanol production

    DEFF Research Database (Denmark)

    2012-01-01

    The present invention relates to a novel anaerobic, extreme thermophilic, ethanol high- yielding bacterium. The invention is based on the isolation of the bacterial strain referred to herein as "DTU01", which produces ethanol as the main fermentation product, followed by acetate and lactate. The ....... The isolated organism is an extremely interesting and very promising organism for the establishment of a sustainable bioethanol production process. The invention further relates to a method for producing a fermentation product such as ethanol.......The present invention relates to a novel anaerobic, extreme thermophilic, ethanol high- yielding bacterium. The invention is based on the isolation of the bacterial strain referred to herein as "DTU01", which produces ethanol as the main fermentation product, followed by acetate and lactate...

  8. PCR detection of thermophilic spore-forming bacteria involved in canned food spoilage.

    Science.gov (United States)

    Prevost, S; Andre, S; Remize, F

    2010-12-01

    Thermophilic bacteria that form highly heat-resistant spores constitute an important group of spoilage bacteria of low-acid canned food. A PCR assay was developed in order to rapidly trace these bacteria. Three PCR primer pairs were designed from rRNA gene sequences. These primers were evaluated for the specificity and the sensitivity of detection. Two primer pairs allowed detection at the species level of Geobacillus stearothermophilus and Moorella thermoacetica/thermoautrophica. The other pair allowed group-specific detection of anaerobic thermophilic bacteria of the genera Thermoanaerobacterium, Thermoanaerobacter, Caldanerobium and Caldanaerobacter. After a single enrichment step, these PCR assays allowed the detection of 28 thermophiles from 34 cans of spoiled low-acid food. In addition, 13 ingredients were screened for the presence of these bacteria. This PCR assay serves as a detection method for strains able to spoil low-acid canned food treated at 55°C. It will lead to better reactivity in the canning industry. Raw materials and ingredients might be qualified not only for quantitative spore contamination, but also for qualitative contamination by highly heat-resistant spores.

  9. Previously unclassified bacteria dominate during thermophilic and mesophilic anaerobic pre-treatment of primary sludge.

    Science.gov (United States)

    Pervin, Hasina M; Batstone, Damien J; Bond, Philip L

    2013-06-01

    Thermophilic biological pre-treatment enables enhanced anaerobic digestion for treatment of wastewater sludges but, at present, there is limited understanding of the hydrolytic-acidogenic microbial composition and its contribution to this process. In this study, the process was assessed by comparing the microbiology of thermophilic (50-65 °C) and mesophilic (35 °C) pre-treatment reactors treating primary sludge. A full-cycle approach for the 16S rRNA genes was applied in order to monitor the diversity of bacteria and their abundance in a thermophilic pre-treatment reactor treating primary sludge. For the thermophilic pre-treatment (TP), over 90% of the sequences were previously undetected and these had less than 97% sequence similarity to cultured organisms. During the first 83 days, members of the Betaproteobacteria dominated the community sequences and a newly designed probe was used to monitor a previously unknown bacterium affiliated with the genus Brachymonas. Between days 85 and 183, three phylotypes that affiliated with the genera Comamonas, Clostridium and Lysobacter were persistently dominant in the TP community, as revealed by terminal-restriction fragment length polymorphism (T-RFLP). Hydrolytic and fermentative functions have been speculated for these bacteria. Mesophilic pre-treatment (MP) and TP communities were different but they were both relatively dynamic. Statistical correlation analysis and the function of closely allied reference organisms indicated that previously unclassified bacteria dominated the TP community and may have been functionally involved in the enhanced hydrolytic performance of thermophilic anaerobic pre-treatment. This study is the first to reveal the diversity and dynamics of bacteria during anaerobic digestion of primary sludge. Copyright © 2013 Elsevier GmbH. All rights reserved.

  10. Biological Hydrogen Production: Simultaneous Saccharification and Fermentation with Nitrogen and Phosphorus Removal from Wastewater Effluent

    Science.gov (United States)

    2012-03-01

    process.7 The reaction is of great economic importance given that the world’s industrial production of nitrogenous fertilizer increased 27-fold between... Enzymatic Saccharification and Fermentation of Paper and Pulp Industry Effluent for Biohydrogen Production . Int. J. Hydrogen Energy 2010, 35, pp...Reactor Setup and Operation 11 4.2 Operational Comparison: SBR and CBR 12 4.3 Effect of pH and Loading on Hydrogen Production 13 4.4 Enzymatic Source

  11. Survival of weed seeds and animal parasites as affected by anaerobic digestion at meso- and thermophilic conditions

    DEFF Research Database (Denmark)

    Johansen, Anders; Bangsø Nielsen, Henrik; Hansen, Christian M.

    2013-01-01

    did not affect egg survival during the first 48h and it took up to 10days before total elimination was reached. In general, anaerobic digestion in biogas plants seems an efficient way (thermophilic more efficient than mesophilic) to treat organic farm wastes in a way that suppresses animal parasites......, Ascaris suum, was assessed under conditions similar to biogas plants managed at meso- (37°C) and thermophilic (55°C) conditions. Cattle manure was used as digestion substrate and experimental units were sampled destructively over time. Regarding weed seeds, the effect of thermophilic conditions (55°C...

  12. Fermentative hydrogen production by diverse microflora

    International Nuclear Information System (INIS)

    Baghchehsaraee, B.; Nakhla, G.; Karamanev, D.; Margaritis, A.

    2009-01-01

    'Full text': In this study of hydrogen production with activated sludge, a diverse bacterial source has been investigated and compared to microflora from anaerobic digester sludge, which is less diverse. Batch experiments were conducted at mesophilic (37 o C) and thermophilic (55 o C) temperatures. The hydrogen production yields with activated sludge at 37 o C and 55 o C were 0.25 and 0.93 mol H 2 /mol glucose, respectively. The maximum hydrogen production rates with activated sludge in both temperatures were 4.2 mL/h. Anaerobic digester sludge showed higher hydrogen production yields and rates at both mesophilic and thermophilic temperatures. The results of repeated batch experiments with activated sludge showed an increase in the hydrogen production during the consecutive batches. However, hydrogen production was not stable along the repeated batches. The observed instability was due to the formation of lactic acid and ethanol. (author)

  13. Simultaneous Production of Hydrogen and Methane from Sugar Beet Molasses in a Two Phase Anaerobic Digestion System in UASB Reactors under Thermophilic Temperature (55 Deg C)

    Energy Technology Data Exchange (ETDEWEB)

    Kongjan, P.; Villafa, S.; Beltran, P.; Min, B.; Angelidaki, I. (Dept. of Environmental Engineering, Technical Univ. of Denmark, DK-2800, Lyngby (Denmark)). e-mail: pak@env.dtu.dk

    2008-10-15

    Simultaneous production of hydrogen and methane in two sequential stages of acidogenic and methanogenic step was investigated in two serial operated up-flow anaerobic sludge bed (UASB) reactors at thermophilic temperature (55 deg C). Hydrogen production from molasses was carried out in the first reactor at the hydraulic retention time (HRT) of 1 day. Molasses were converted into hydrogen with the yield of 1.3 mole-H{sub 2}/mole-hexose{sub added} or 82.7 ml- H{sub 2}/g-VS{sub added} of molasses, and the hydrogen productivity was 2696 ml-H{sub 2}/dxl{sub reactor}. The effluent (mainly butyrate, acetate and lactate) after the acidogenic process was subsequently fed to the second reactor for methane production at HRT of 3 days. Methane production yield of 255 ml-H{sub 2}/g-VS{sub added} of influent or 130.1 ml-H{sub 2}/g-VS{sub added} of molasses and methane production rate of 1056 ml/dxl{sub reactor} were obtained. Significant decrease of volatile fatty acids (VFAs) was also observed in the effluent of the second reactor. A two phase anaerobic digestion was successfully demonstrated for molasses as a potential substrate to produce hydrogen and subsequent methane in the UASB reactors

  14. Assessing the Life-Cycle Performance of Hydrogen Production via Biofuel Reforming in Europe

    Directory of Open Access Journals (Sweden)

    Ana Susmozas

    2015-06-01

    Full Text Available Currently, hydrogen is mainly produced through steam reforming of natural gas. However, this conventional process involves environmental and energy security concerns. This has led to the development of alternative technologies for (potentially green hydrogen production. In this work, the environmental and energy performance of biohydrogen produced in Europe via steam reforming of glycerol and bio-oil is evaluated from a life-cycle perspective, and contrasted with that of conventional hydrogen from steam methane reforming. Glycerol as a by-product from the production of rapeseed biodiesel and bio-oil from the fast pyrolysis of poplar biomass are considered. The processing plants are simulated in Aspen Plus® to provide inventory data for the life cycle assessment. The environmental impact potentials evaluated include abiotic depletion, global warming, ozone layer depletion, photochemical oxidant formation, land competition, acidification and eutrophication. Furthermore, the cumulative (total and non-renewable energy demand is calculated, as well as the corresponding renewability scores and life-cycle energy balances and efficiencies of the biohydrogen products. In addition to quantitative evidence of the (expected relevance of the feedstock and impact categories considered, results show that poplar-derived bio-oil could be a suitable feedstock for steam reforming, in contrast to first-generation bioglycerol.

  15. Isolation of thermophilic Desulfotomaculum strains with methanol and sulphite from solfataric mud pools, and characterization of Desulfotomaculum solfataricum

    NARCIS (Netherlands)

    Goorissen, H.P.; Stams, A.J.M.; Hansen, T.A.

    2003-01-01

    Four strains of thermophilic, endospore-forming, sulfate-reducing bacteria were enriched and isolated from hot solfataric fields in the Krafla area of north-east Iceland, using methanol and sulfite as substrates. Morphologically, these strains resembled thermophilic Desulfotomaculum species. The

  16. Cellulolytic properties of an extremely thermophilic anaerobe

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, J A; Morgan, H W; Daniel, R M [Waikato Univ., Hamilton (New Zealand). Microbial Biochemistry and Biotechnology Unit

    1990-09-01

    An extremely thermophilic anaerobe was isolated from a New Zealand hot spring by incubating bacterial mat strands in a medium containing xylan. The Gramreaction-negative organism that was subsequently purified had a temperature optimum of 70deg C and a pH optimum of 7.0. The isolate, designated strain H173, grew on a restricted range of carbon sources. In batch culture H173 could degrade Avicel completely when supplied at 5 or 10 g l{sup -1}. There was an initial growth phase, during which a cellulase complex was produced and carbohydrates fermented to form acetic and lactic acids, followed by a phase where cells were not metabolising but the cellulase complex actively converted cellulose to glucose. When co-cultered with strain Rt8.B1, an ethanologenic extreme thermophile, glucose was fermented to ethanol and acetate, and no reducing sugars accumulated in the medium. In pH controlled batch culture H173 produced an increased amount of lactate and acetate but there was again a phase when reducing sugars accumulated in the medium, and these were converted to ethanol by co-culture with Rt8.B1. (orig.).

  17. Chlorophyll a with a farnesyl tail in thermophilic cyanobacteria.

    Science.gov (United States)

    Wiwczar, Jessica M; LaFountain, Amy M; Wang, Jimin; Frank, Harry A; Brudvig, Gary W

    2017-11-01

    Photosystem II (PSII) of oxygenic photosynthetic organisms normally contains exclusively chlorophyll a (Chl a) as its major light-harvesting pigment. Chl a canonically consists of the chlorin headgroup with a 20-carbon, 4-isoprene unit, phytyl tail. We have examined the 1.9 Å crystal structure of PSII from thermophilic cyanobacteria reported by Shen and coworkers in 2012 (PDB accession of 3ARC/3WU2). A newly refined electron density map from this structure, presented here, reveals that some assignments of the cofactors may be different from those modeled in the 3ARC/3WU2 structure, including a specific Chl a that appears to have a truncated tail by one isoprene unit. We provide experimental evidence using high-performance liquid chromatography and mass spectrometry for a small population of Chl a esterified to a 15-carbon farnesyl tail in PSII of thermophilic cyanobacteria.

  18. Biocorrosive Thermophilic Microbial Communities in Alaskan North Slope Oil Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, Kathleen E.; Gieg, Lisa M.; Parisi, Victoria A.; Tanner, Ralph S.; Green Tringe, Susannah; Bristow, Jim; Suflita, Joseph M.

    2009-09-16

    Corrosion of metallic oilfield pipelines by microorganisms is a costly but poorly understood phenomenon, with standard treatment methods targeting mesophilic sulfatereducing bacteria. In assessing biocorrosion potential at an Alaskan North Slope oil field, we identified thermophilic hydrogen-using methanogens, syntrophic bacteria, peptideand amino acid-fermenting bacteria, iron reducers, sulfur/thiosulfate-reducing bacteria and sulfate-reducing archaea. These microbes can stimulate metal corrosion through production of organic acids, CO2, sulfur species, and via hydrogen oxidation and iron reduction, implicating many more types of organisms than are currently targeted. Micromolar quantities of putative anaerobic metabolites of C1-C4 n-alkanes in pipeline fluids were detected, implying that these low molecular weight hydrocarbons, routinely injected into reservoirs for oil recovery purposes, are biodegraded and provide biocorrosive microbial communities with an important source of nutrients.

  19. Extreme thermophilic ethanol production from rapeseed straw: using the newly isolated Thermoanaerobacter pentosaceus and combining it with Saccharomyces cerevisiae in a two-step process

    DEFF Research Database (Denmark)

    Tomás, Ana Faria; Karagöz, Pınar; Karakashev, Dimitar Borisov

    2013-01-01

    from the liquid fraction of pretreated rapeseed straw, without any dilution or need for additives. However, when the hydrolysate was used undiluted the ethanol yield was only 37% compared to yield of the control, in which pure sugars in synthetic medium were used. The decrease of ethanol yield...... showed that the two strains together could achieve up to 85% of the theoretical ethanol yield based on the sugar composition of the rapeseed straw, which was 14% and 50% higher compared to the yield with the yeast or the bacteria alone, respectively. Biotechnol. Bioeng. © 2012 Wiley Periodicals, Inc.......The newly isolated extreme thermophile Thermoanaerobacter pentosaceus was used for ethanol production from alkaline-peroxide pretreated rapeseed straw (PRS). Both the liquid and solid fractions of PRS were used. T. pentosaceus was able to metabolize the typical process inhibitors present...

  20. Draft Genome Sequence of Aeribacillus pallidus Strain 8m3, a Thermophilic Hydrocarbon-Oxidizing Bacterium Isolated from the Dagang Oil Field (China).

    Science.gov (United States)

    Poltaraus, Andrey B; Sokolova, Diyana S; Grouzdev, Denis S; Ivanov, Timophey M; Malakho, Sophia G; Korshunova, Alena V; Rozanov, Aleksey S; Tourova, Tatiyana P; Nazina, Tamara N

    2016-06-09

    The draft genome sequence of Aeribacillus pallidus strain 8m3, a thermophilic aerobic oil-oxidizing bacterium isolated from production water from the Dagang high-temperature oil field, China, is presented here. The genome is annotated to provide insights into the genomic and phenotypic diversity of the genus Aeribacillus. Copyright © 2016 Poltaraus et al.