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)

Cultivable anaerobic and aerobic bacterial communities in the fermentation chambers of Holotrichia parallela (coleoptera: scarabaeidae) larvae.

Science.gov (United States)

Zhang, Zhen-Yu; Yuan, Yimin; Ali, Muhammad Waqar; Peng, Tao; Peng, Wei; Raza, Muhammad Fahim; Zhao, Yongshun; Zhang, Hongyu

2018-01-01

As important pests, scarab beetle larvae survive on plant biomass and the microbiota of the fermentation chamber play an important role in the digestion of lignocellulose-rich diets. However, the cultivable microbes, especially the anaerobic cultivable microbes, are still largely unknown. Here, both cultivable anaerobic and aerobic bacterial communities associated with the fermentation chamber of Holotrichia parallela larvae were investigated. In total bacteria cells directly enumerated by the 4', 6-diamidino-2-phenylindole (DAPI) staining method, the viable plate counts of cultivable bacteria in the fermentation chamber accounted for 0.92% of proportion. These cultivable bacteria were prone to attach to the fermentation chamber wall (88.41%) compared to the chamber contents. Anaerobic bacteria were dominant in the cultivable bacteria attaching to the fermentation chamber wall (70.20%), while the quantities of anaerobes and aerobes were similar in the chamber contents. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), fingerprinting and sequence analysis of isolated colonies revealed that the cultivable bacteria are affiliated with class γ-Proteobacteria, Bacteroidia, Actinobacteria, Clostridia and β-Proteobacteria. γ-Proteobacteria was the major type of anaerobic cultivable bacteria and even the only one type of aerobic cultivable bacteria. Taken together, our results suggest, for the first time, that anaerobic microbiota are dominant in cultivable bacteria in the special anoxia niche of the fermentation chamber from H. parallela larvae. These bacterial isolates could be a treasure trove for screening lignocellulytic microbes which are essential for the plant biomass digestion of this scarab species.

Cultivable anaerobic and aerobic bacterial communities in the fermentation chambers of Holotrichia parallela (coleoptera: scarabaeidae) larvae

Science.gov (United States)

Ali, Muhammad Waqar; Peng, Tao; Peng, Wei; Raza, Muhammad Fahim; Zhao, Yongshun; Zhang, Hongyu

2018-01-01

As important pests, scarab beetle larvae survive on plant biomass and the microbiota of the fermentation chamber play an important role in the digestion of lignocellulose-rich diets. However, the cultivable microbes, especially the anaerobic cultivable microbes, are still largely unknown. Here, both cultivable anaerobic and aerobic bacterial communities associated with the fermentation chamber of Holotrichia parallela larvae were investigated. In total bacteria cells directly enumerated by the 4’, 6-diamidino-2-phenylindole (DAPI) staining method, the viable plate counts of cultivable bacteria in the fermentation chamber accounted for 0.92% of proportion. These cultivable bacteria were prone to attach to the fermentation chamber wall (88.41%) compared to the chamber contents. Anaerobic bacteria were dominant in the cultivable bacteria attaching to the fermentation chamber wall (70.20%), while the quantities of anaerobes and aerobes were similar in the chamber contents. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), fingerprinting and sequence analysis of isolated colonies revealed that the cultivable bacteria are affiliated with class γ-Proteobacteria, Bacteroidia, Actinobacteria, Clostridia and β-Proteobacteria. γ-Proteobacteria was the major type of anaerobic cultivable bacteria and even the only one type of aerobic cultivable bacteria. Taken together, our results suggest, for the first time, that anaerobic microbiota are dominant in cultivable bacteria in the special anoxia niche of the fermentation chamber from H. parallela larvae. These bacterial isolates could be a treasure trove for screening lignocellulytic microbes which are essential for the plant biomass digestion of this scarab species. PMID:29304141

Effects of household detergent on anaerobic fermentation of kitchen wastewater from food waste disposer.

Science.gov (United States)

Lee, K H; Park, K Y; Khanal, S K; Lee, J W

2013-01-15

This study examines the effects of household detergent on anaerobic methane fermentation of wastewater from food waste disposers (FWDs). Anaerobic toxicity assay (ATA) demonstrated that methane production substantially decreased at a higher detergent concentration. The Gompertz three-parameter model fitted well with the ATA results, and both the extent of methane production (M) and methane production rate (R(m)) obtained from the model were strongly affected by the concentration of the detergent. The 50% inhibitory concentration (IC(50)) of the detergent was 603 mg/L based on R(m). Results from fatty acid methyl esters (FAMEs) analysis of microbial culture revealed that deterioration of methane fermentation was attributed to impaired structure of anaerobic microbial membrane due to detergent. This study suggests that wastewater from FWD could be used for methane production, but it is necessary to reduce the concentration of detergent prior to anaerobic fermentation. Copyright © 2012 Elsevier B.V. All rights reserved.

Pathways and bioenergetics of anaerobic carbon monoxide fermentation

NARCIS (Netherlands)

Diender, Martijn; Stams, Fons; Machado de Sousa, Diana

2015-01-01

Carbon monoxide can act as a substrate for different modes of fermentative anaerobic metabolism. The trait of utilizing CO is spread among a diverse group of microorganisms, including members of bacteria as well as archaea. Over the last decade this metabolism has gained interest due to the

Enhanced coproduction of hydrogen and methane from cornstalks by a three-stage anaerobic fermentation process integrated with alkaline hydrolysis.

Science.gov (United States)

Cheng, Xi-Yu; Liu, Chun-Zhao

2012-01-01

A three-stage anaerobic fermentation process including H(2) fermentation I, H(2) fermentation II, methane fermentation was developed for the coproduction of hydrogen and methane from cornstalks. Hydrogen production from cornstalks using direct microbial conversion by Clostridium thermocellum 7072 was markedly enhanced in the two-stage thermophilic hydrogen fermentation process integrated with alkaline treatment. The highest total hydrogen yield from cornstalks in the two-stage fermentation process reached 74.4 mL/g-cornstalk. The hydrogen fermentation effluents and alkaline hydrolyzate were further used for methane fermentation by anaerobic granular sludge, and the total methane yield reached 205.8 mL/g-cornstalk. The total energy recovery in the three-stage anaerobic fermentation process integrated with alkaline hydrolysis reached 70.0%. Copyright © 2011 Elsevier Ltd. All rights reserved.

Transcriptomic and metabolomic profiling of Zymomonas mobilis during aerobic and anaerobic fermentations

Directory of Open Access Journals (Sweden)

Palumbo Anthony V

2009-01-01

Full Text Available Abstract Background Zymomonas mobilis ZM4 (ZM4 produces near theoretical yields of ethanol with high specific productivity and recombinant strains are able to ferment both C-5 and C-6 sugars. Z. mobilis performs best under anaerobic conditions, but is an aerotolerant organism. However, the genetic and physiological basis of ZM4's response to various stresses is understood poorly. Results In this study, transcriptomic and metabolomic profiles for ZM4 aerobic and anaerobic fermentations were elucidated by microarray analysis and by high-performance liquid chromatography (HPLC, gas chromatography (GC and gas chromatography-mass spectrometry (GC-MS analyses. In the absence of oxygen, ZM4 consumed glucose more rapidly, had a higher growth rate, and ethanol was the major end-product. Greater amounts of other end-products such as acetate, lactate, and acetoin were detected under aerobic conditions and at 26 h there was only 1.7% of the amount of ethanol present aerobically as there was anaerobically. In the early exponential growth phase, significant differences in gene expression were not observed between aerobic and anaerobic conditions via microarray analysis. HPLC and GC analyses revealed minor differences in extracellular metabolite profiles at the corresponding early exponential phase time point. Differences in extracellular metabolite profiles between conditions became greater as the fermentations progressed. GC-MS analysis of stationary phase intracellular metabolites indicated that ZM4 contained lower levels of amino acids such as alanine, valine and lysine, and other metabolites like lactate, ribitol, and 4-hydroxybutanoate under anaerobic conditions relative to aerobic conditions. Stationary phase microarray analysis revealed that 166 genes were significantly differentially expressed by more than two-fold. Transcripts for Entner-Doudoroff (ED pathway genes (glk, zwf, pgl, pgk, and eno and gene pdc, encoding a key enzyme leading to ethanol

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)

Trends in the development of equipment for anaerobic fermentation

Energy Technology Data Exchange (ETDEWEB)

Holcak, B; Lutcha, J

1982-01-01

The successful application of anaerobic fermentation to the utilization of diluted wastes for the production of energy stimulated in recent years the development of new types of anaerobic reactors. Although the point of view of a chemical engineer does not encompass the complexity of this microbial process, he still disposes of means that enable him to estimate to what extent is it possible to affect the efficiency of the process by the concept of reactor arrangement. Simulation of behaviour by means of mathematical models enables us to compare quantitatively, for the types of anaerobic reactor under consideration, the apparatuses, and to predict the expected trends in their development.

Pathways and bioenergetics of anaerobic carbon monoxide fermentation.

Directory of Open Access Journals (Sweden)

Martijn eDiender

2015-11-01

Full Text Available Carbon monoxide can act as a substrate for different modes of fermentative anaerobic metabolism. The trait of utilizing CO is spread among a diverse group of microorganisms, including members of bacteria as well as archaea. Over the last decade this metabolism has gained interest due to the potential of converting CO rich gas, such as synthesis gas, into bio-based products. Three main types of fermentative CO metabolism can be distinguished: hydrogenogenesis, methanogenesis and acetogenesis, generating hydrogen, methane and acetate, respectively. Here, we review the current knowledge on these three variants of microbial CO metabolism with an emphasis on the potential enzymatic routes and bio-energetics involved.

Pathways and Bioenergetics of Anaerobic Carbon Monoxide Fermentation.

Science.gov (United States)

Diender, Martijn; Stams, Alfons J M; Sousa, Diana Z

2015-01-01

Carbon monoxide can act as a substrate for different modes of fermentative anaerobic metabolism. The trait of utilizing CO is spread among a diverse group of microorganisms, including members of bacteria as well as archaea. Over the last decade this metabolism has gained interest due to the potential of converting CO-rich gas, such as synthesis gas, into bio-based products. Three main types of fermentative CO metabolism can be distinguished: hydrogenogenesis, methanogenesis, and acetogenesis, generating hydrogen, methane and acetate, respectively. Here, we review the current knowledge on these three variants of microbial CO metabolism with an emphasis on the potential enzymatic routes and bio-energetics involved.

Mono-fermentation of shea waste in anaerobic digesters - laboratory ...

African Journals Online (AJOL)

For the purpose of understanding the characteristics in performance of the shea waste and to provide the necessary input parameters towards the design of biogas plants, mono-fermentation as an option in anaerobic digestion for energy (methane) generation was investigated. Six horizontal reactors with a liquid volume of ...

Cassava stillage and its anaerobic fermentation liquid as external carbon sources in biological nutrient removal.

Science.gov (United States)

Bu, Fan; Hu, Xiang; Xie, Li; Zhou, Qi

2015-04-01

The aim of this study was to investigate the effects of one kind of food industry effluent, cassava stillage and its anaerobic fermentation liquid, on biological nutrient removal (BNR) from municipal wastewater in anaerobic-anoxic-aerobic sequencing batch reactors (SBRs). Experiments were carried out with cassava stillage supernatant and its anaerobic fermentation liquid, and one pure compound (sodium acetate) served as an external carbon source. Cyclic studies indicated that the cassava by-products not only affected the transformation of nitrogen, phosphorus, poly-β-hydroxyalkanoates (PHAs), and glycogen in the BNR process, but also resulted in higher removal efficiencies for phosphorus and nitrogen compared with sodium acetate. Furthermore, assays for phosphorus accumulating organisms (PAOs) and denitrifying phosphorus accumulating organisms (DPAOs) demonstrated that the proportion of DPAOs to PAOs reached 62.6% (Day 86) and 61.8% (Day 65) when using cassava stillage and its anaerobic fermentation liquid, respectively, as the external carbon source. In addition, the nitrate utilization rates (NURs) of the cassava by-products were in the range of 5.49-5.99 g N/(kg MLVSS⋅h) (MLVSS is mixed liquor volatile suspended solids) and 6.63-6.81 g N/(kg MLVSS⋅h), respectively. The improvement in BNR performance and the reduction in the amount of cassava stillage to be treated in-situ make cassava stillage and its anaerobic fermentation liquid attractive alternatives to sodium acetate as external carbon sources for BNR processes.

Cassava stillage and its anaerobic fermentation liquid as external carbon sources in biological nutrient removal*

Science.gov (United States)

Bu, Fan; Hu, Xiang; Xie, Li; Zhou, Qi

2015-01-01

The aim of this study was to investigate the effects of one kind of food industry effluent, cassava stillage and its anaerobic fermentation liquid, on biological nutrient removal (BNR) from municipal wastewater in anaerobic-anoxic-aerobic sequencing batch reactors (SBRs). Experiments were carried out with cassava stillage supernatant and its anaerobic fermentation liquid, and one pure compound (sodium acetate) served as an external carbon source. Cyclic studies indicated that the cassava by-products not only affected the transformation of nitrogen, phosphorus, poly-β-hydroxyalkanoates (PHAs), and glycogen in the BNR process, but also resulted in higher removal efficiencies for phosphorus and nitrogen compared with sodium acetate. Furthermore, assays for phosphorus accumulating organisms (PAOs) and denitrifying phosphorus accumulating organisms (DPAOs) demonstrated that the proportion of DPAOs to PAOs reached 62.6% (Day 86) and 61.8% (Day 65) when using cassava stillage and its anaerobic fermentation liquid, respectively, as the external carbon source. In addition, the nitrate utilization rates (NURs) of the cassava by-products were in the range of 5.49–5.99 g N/(kg MLVSS∙h) (MLVSS is mixed liquor volatile suspended solids) and 6.63–6.81 g N/(kg MLVSS∙h), respectively. The improvement in BNR performance and the reduction in the amount of cassava stillage to be treated in-situ make cassava stillage and its anaerobic fermentation liquid attractive alternatives to sodium acetate as external carbon sources for BNR processes. PMID:25845364

Modified ADM1 for modeling free ammonia inhibition in anaerobic acidogenic fermentation with high-solid sludge.

Science.gov (United States)

Bai, Jie; Liu, He; Yin, Bo; Ma, Huijun; Chen, Xinchun

2017-02-01

Anaerobic acidogenic fermentation with high-solid sludge is a promising method for volatile fatty acid (VFA) production to realize resource recovery. In this study, to model inhibition by free ammonia in high-solid sludge fermentation, the anaerobic digestion model No. 1 (ADM1) was modified to simulate the VFA generation in batch, semi-continuous and full scale sludge. The ADM1 was operated on the platform AQUASIM 2.0. Three kinds of inhibition forms, e.g., simple inhibition, Monod and non-inhibition forms, were integrated into the ADM1 and tested with the real experimental data for batch and semi-continuous fermentation, respectively. The improved particle swarm optimization technique was used for kinetic parameter estimation using the software MATLAB 7.0. In the modified ADM1, the K s of acetate is 0.025, the k m,ac is 12.51, and the K I_NH3 is 0.02, respectively. The results showed that the simple inhibition model could simulate the VFA generation accurately while the Monod model was the better inhibition kinetics form in semi-continuous fermentation at pH10.0. Finally, the modified ADM1 could successfully describe the VFA generation and ammonia accumulation in a 30m 3 full-scale sludge fermentation reactor, indicating that the developed model can be applicable in high-solid sludge anaerobic fermentation. Copyright © 2016. Published by Elsevier B.V.

Evaluation of two-phase thermophilic anaerobic methane fermentation for the treatment of garbage

International Nuclear Information System (INIS)

Park, Y.J.; Hong, F.; Japan Science and Technology Agency, Tokyo; Tsuno, H.; Hidaka, T.; Cheon, J.H.; Japan Science and Technology Agency, Tokyo

2004-01-01

Municipal solid wastes (MSW) in Japan are generally incinerated. However, in recent years, garbage has been recognized as a renewable energy source. This has resulted in an increase in the use of biological processes, such as anaerobic digestion, to treat organic waste such as sewage sludge and garbage. The two phases of anaerobic digestion are the acidogenic phase and the methane producing phase. Both differ significantly in their nutritional and physiological requirements. This study evaluated the effectiveness of treating garbage with the two-phase thermophilic methane fermentation system (TPS). The performance of the acid fermentation phase in TPS was examined with particular reference to operational parameters such as pH, hydraulic retention time and organic loading rate on volatile fatty acid fermentation. It was shown that TPS was more efficient than the single-phase thermophilic methane fermentation system (SPS). Acidification control in the first stage resulted in better stability of methane fermentation in the second stage. VFA formation was optimized at a pH of 6. The recovery ratios of VFAs and methane were achieved in the range of 42 to 44 per cent and 88 to 91 per cent of garbage by high organic loading rate respectively. 12 refs., 6 tabs., 4 figs

Preparation of low galactose yogurt using cultures of Gal(+) Streptococcus thermophilus in combination with Lactobacillus delbrueckii ssp. bulgaricus.

Science.gov (United States)

Anbukkarasi, Kaliyaperumal; UmaMaheswari, Thiyagamoorthy; Hemalatha, Thiagarajan; Nanda, Dhiraj Kumar; Singh, Prashant; Singh, Rameshwar

2014-09-01

Streptococcus thermophilus is an important lactic starter used in the production of yogurt. Most strains of S. thermophilus are galactose negative (Gal(-)) and are able to metabolize only glucose portion of lactose and expel galactose into the medium. This metabolic defect leads to the accumulation of free galactose in yogurt, resulting in galactosemia among consumers. Hence there is an absolute need to develop low galactose yogurt. Therefore, in this study, three galactose positive (Gal(+)) S. thermophilus strains from National Collection of Dairy Cultures (NCDC) viz. NCDC 659 (AJM), NCDC 660 (JM1), NCDC 661 (KM3) and a reference galactose negative (Gal(-)) S. thermophilus NCDC 218 were used for preparation of low galactose yogurt. In milk fermented using S. thermophilus isolates alone, NCDC 659 released less galactose (0.27 %) followed by NCDC 661 (0.3 %) and NCDC 660 (0.45 %) after 10 h at 42 °C. Milk was fermented in combination with Gal(-) L. delbrueckii subsp. bulgaricus NCDC 04, in which NCDC 659 released least galactose upto 0.49 % followed by NCDC 661 (0.51 %) and NCDC 660 (0.60 %) than reference Gal(-) NCDC 218(0.79 %). Low galactose yogurt was prepared following standard procedure using Gal(+) S. thermophilus isolates and Gal(-) L. delbrueckii subsp. bulgaricus NCDC 04 in 1:1 ratio. Among which low galactose yogurt by NCDC 659 combination contained less galactose 0.37 % followed by NCDC 661 (0.51 %), NCDC 660 (0.65 %) and reference Gal(-) NCDC 218 (0.98 %) after 4 h of fermentation. This study clearly reveals that Gal(+) S. thermophilus isolates can be paired with Gal(-) L. delbrueckii subsp. bulgaricus for developing low galactose yogurt.

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)

A study of the process of two staged anaerobic fermentation as a possible method for purifying sewage

Energy Technology Data Exchange (ETDEWEB)

Inoue, Y; Kouama, K; Matsuo, T

1983-01-01

Great attention has recently been given to the study of the processes of anaerobic fermentation, which may become alternatives to the existing methods for purifying waste waters which use aerobic microorganisms. A series of experimentswere conducted with the use of an artificially prepared liquid (fermented milk and starch) which imitates the waste to be purified, in order to explain the capabilities of the process of two staged anaerobic fermentation (DAS) as a method for purifying waste waters. The industrial system of the process includes: a fermentation vat for acetic fermentation with recirculation of the sediment, a primary settler, a fermentation tank for methane fermentation and a secondary settler. The process was conducted at a loading speed (based on Carbon) from 0.15 to 0.4 kilograms per cubic meter per day at a temperature of 38C. The degree of conversion of the fermented organic substances into volatile organic acids was not a function of the loading speed and was 54 to 57 percent in the acetic fermentation tank, where 95 to 97 percent of the organic material was broken down with the production of methane and carbon dioxide.

Anaerobic survival of Pseudomonas aeruginosa by pyruvate fermentation requires an Usp-type stress protein

DEFF Research Database (Denmark)

Schreiber, K; Boes, N; Escbach, M

2006-01-01

the induced synthesis of three enzymes involved in arginine fermentation, ArcA, ArcB, and ArcC, and the outer membrane protein OprL. Moreover, formation of two proteins of unknown function, PA3309 and PA4352, increased by factors of 72- and 22-fold, respectively. Both belong to the group of universal stress...... proteins (Usp). Long-term survival of a PA3309 knockout mutant by pyruvate fermentation was found drastically reduced. The oxygen-sensing regulator Anr controls expression of the PPA3309-lacZ reporter gene fusion after a shift to anaerobic conditions and further pyruvate fermentation. PA3309 expression...... was also found induced during the anaerobic and aerobic stationary phases. This aerobic stationary-phase induction is independent of the regulatory proteins Anr, RpoS, RelA, GacA, RhlR, and LasR, indicating a currently unknown mechanism of stationary-phase-dependent gene activation. PA3309 promoter...

Continuous determination of volatile products in anaerobic fermenters by on-line capillary gas chromatography

International Nuclear Information System (INIS)

Diamantis, V.; Melidis, P.; Aivasidis, A.

2006-01-01

Bio-ethanol and biogas produced during the anaerobic conversion of organic compounds has been a subject of great interest since the oil crisis of the 1970s. In ethanol fermentation and anaerobic treatment of wastewaters, end-product (ethanol) and intermediate-products (short-chain fatty acids, SCFA) cause inhibition that results in reduced process efficiency. Control of these constituents is of utmost importance for bioreactor optimization and process stability. Ethanol and SCFA can be detected with precision by capillary gas chromatography usually conducted in off-line measurements. In this work, an on-line monitoring and controlling system was developed and connected to the fermenter via an auto-sampling equipment, which could perform the feeding, filtration and dilution of the sample and final injection into the gas chromatograph through an automation-based programmed procedure. The sample was continuously pumped from the recycle stream of the bioreactor and treated using a microfiltration unit. The concentrate was returned to the reactor while the permeate was quantitatively mixed with an internal standard solution. The system comprised of a gas chromatograph with the flow cell and one-shot sampler and a PC with the appropriate software. The on-line measurement of ethanol and SCFA, directly from the liquid phase of an ethanol fermenter and a high-rate continuous mode anaerobic digester, was accomplished by gas chromatography. Also, this monitoring and controlling system was proved to be effective in the continuous fermentation of alcohol-free beer

Mixotrophic Chlorella sp. UJ-3 cultivation in the typical anaerobic fermentation effluents.

Science.gov (United States)

Huo, Shuhao; Kong, Miao; Zhu, Feifei; Zou, Bin; Wang, Feng; Xu, Ling; Zhang, Cunsheng; Huang, Daming

2018-02-01

The growth of mixotrophic Chlorella sp. UJ-3 cultivated in the three typical anaerobic fermentation effluents was investigated in this paper. The results showed that the microalgae grew best under intermediate light intensity for all the types of fermentation effluents. The butyrate type fermentation effluents induced the fastest growth rate for Chlorella sp. UJ-3, with a maximal cell concentration of 3.8×10 7  cells/mL. Under intermediate light intensity, the volatile fatty acids (VFAs) were almost depleted on the fifth day of the cultivation for all the three types of fermentation systems. The ratios of chlorophyll a/b were all increased for the three systems, indicating enhanced energy-capturing capability of the microalgae for photosynthesis after the VFAs were depleted. The highest lipid content was 25.4%dwt achieved in the butyrate type fermentation, and the fatty acid compositions were found to be considerably different for these three types of fermentation systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydrogen production characteristics of the organic fraction of municipal solid wastes by anaerobic mixed culture fermentation

Energy Technology Data Exchange (ETDEWEB)

Dong, Li; Yu, Zhang [Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China)]|[Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Zhenhong, Yuan; Yongming, Sun; Xiaoying, Kong [Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China)

2009-01-15

The hydrogen production from the organic fraction of municipal solid waste (OFMSW) by anaerobic mixed culture fermentation was investigated using batch experiments at 37 C. Seven varieties of typical individual components of OFMSW including rice, potato, lettuce, lean meat, oil, fat and banyan leaves were selected to estimate the hydrogen production potential. Experimental results showed that the boiling treated anaerobic sludge was effective mixed inoculum for fermentative hydrogen production from OFMSW. Mechanism of fermentative hydrogen production indicates that, among the OFMSW, carbohydrates is the most optimal substrate for fermentative hydrogen production compared with proteins, lipids and lignocelluloses. This conclusion was also substantiated by experimental results of this study. The hydrogen production potentials of rice, potato and lettuce were 134 mL/g-VS, 106 mL/g-VS, and 50 mL/g-VS respectively. The hydrogen percentages of the total gas produced from rice, potato and lettuce were 57-70%, 41-55% and 37-67%. (author)

Fermentative degradation of polyethylene glycol by a strictly anaerobic, gram-negative, nonsporeforming bacterium, Pelobacter venetianus sp. nov.

Science.gov (United States)

Schink, B; Stieb, M

1983-06-01

The synthetic polyether polyethylene glycol (PEG) with a molecular weight of 20,000 was anaerobically degraded in enrichment cultures inoculated with mud of limnic and marine origins. Three strains (Gra PEG 1, Gra PEG 2, and Ko PEG 2) of rod-shaped, gram-negative, nonsporeforming, strictly anaerobic bacteria were isolated in mineral medium with PEG as the sole source of carbon and energy. All strains degraded dimers, oligomers, and polymers of PEG up to a molecular weight of 20,000 completely by fermentation to nearly equal amounts of acetate and ethanol. The monomer ethylene glycol was not degraded. An ethylene glycol-fermenting anaerobe (strain Gra EG 12) isolated from the same enrichments was identified as Acetobacterium woodii. The PEG-fermenting strains did not excrete extracellular depolymerizing enzymes and were inhibited by ethylene glycol, probably owing to a blocking of the cellular uptake system. PEG, some PEG-containing nonionic detergents, 1,2-propanediol, 1,2-butanediol, glycerol, and acetoin were the only growth substrates utilized of a broad variety of sugars, organic acids, and alcohols. The isolates did not reduce sulfate, sulfur, thiosulfate, or nitrate and were independent of growth factors. In coculture with A. woodii or Methanospirillum hungatei, PEGs and ethanol were completely fermented to acetate (and methane). A marine isolate is described as the type strain of a new species, Pelobacter venetianus sp. nov. Its physiology and ecological significance, as well as the importance and possible mechanism of anaerobic polyether degradation, are discussed.

Hydrogen and methane production from condensed molasses fermentation soluble by a two-stage anaerobic process

Energy Technology Data Exchange (ETDEWEB)

Lin, Chiu-Yue; Liang, You-Chyuan; Lay, Chyi-How [Feng Chia Univ., Taichung, Taiwan (China). Dept. of Environmental Engineering and Science; Chen, Chin-Chao [Chungchou Institute of Technology, Taiwan (China). Environmental Resources Lab.; Chang, Feng-Yuan [Feng Chia Univ., Taichung, Taiwan (China). Research Center for Energy and Resources

2010-07-01

The treatment of condensed molasses fermentation soluble (CMS) is a troublesome problem for glutamate manufacturing factory. However, CMS contains high carbohydrate and nutrient contents and is an attractive and commercially potential feedstock for bioenergy production. The aim of this paper is to produce hydrogen and methane by two-stage anaerobic fermentation process. The fermentative hydrogen production from CMS was conducted in a continuously-stirred tank bioreactor (working volume 4 L) which was operated at a hydraulic retention time (HRT) of 8 h, organic loading rate (OLR) of 120 kg COD/m{sup 3}-d, temperature of 35 C, pH 5.5 and sewage sludge as seed. The anaerobic methane production was conducted in an up-flow bioreactor (working volume 11 L) which was operated at a HRT of 24 -60 hrs, OLR of 4.0-10 kg COD/m{sup 3}-d, temperature of 35 C, pH 7.0 with using anaerobic granule sludge from fructose manufacturing factory as the seed and the effluent from hydrogen production process as the substrate. These two reactors have been operated successfully for more than 400 days. The steady-state hydrogen content, hydrogen production rate and hydrogen production yield in the hydrogen fermentation system were 37%, 169 mmol-H{sub 2}/L-d and 93 mmol-H{sub 2}/g carbohydrate{sub removed}, respectively. In the methane fermentation system, the peak methane content and methane production rate were 66.5 and 86.8 mmol-CH{sub 4}/L-d with methane production yield of 189.3 mmol-CH{sub 4}/g COD{sub removed} at an OLR 10 kg/m{sup 3}-d. The energy production rate was used to elucidate the energy efficiency for this two-stage process. The total energy production rate of 133.3 kJ/L/d was obtained with 5.5 kJ/L/d from hydrogen fermentation and 127.8 kJ/L/d from methane fermentation. (orig.)

Enhancing phosphorus release from waste activated sludge containing ferric or aluminum phosphates by EDTA addition during anaerobic fermentation process.

Science.gov (United States)

Zou, Jinte; Zhang, Lili; Wang, Lin; Li, Yongmei

2017-03-01

The effect of ethylene diamine tetraacetic acid (EDTA) addition on phosphorus release from biosolids and phosphate precipitates during anaerobic fermentation was investigated. Meanwhile, the impact of EDTA addition on the anaerobic fermentation process was revealed. The results indicate that EDTA addition significantly enhanced the release of phosphorus from biosolids, ferric phosphate precipitate and aluminum phosphate precipitate during anaerobic fermentation, which is attributed to the complexation of metal ions and damage of cell membrane caused by EDTA. With the optimal EDTA addition of 19.5 mM (0.41 gEDTA/gSS), phosphorus release efficiency from biosolids was 82%, which was much higher than that (40%) without EDTA addition. Meanwhile, with 19.5 mM EDTA addition, almost all the phosphorus in ferric phosphate precipitate was released, while only 57% of phosphorus in aluminum phosphate precipitate was released. This indicates that phosphorus in ferric phosphate precipitate was much easier to be released than that in aluminum phosphate precipitate during anaerobic fermentation of sludge. In addition, proper EDTA addition facilitated the production of soluble total organic carbon and volatile fatty acids, as well as solid reduction during sludge fermentation, although methane production could be inhibited. Therefore, EDTA addition can be used as an alternative method for recovering phosphorus from waste activated sludge containing ferric or aluminum precipitates, as well as recovery of soluble carbon source. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gas production in anaerobic dark-fermentation processes from agriculture solid waste

Science.gov (United States)

Sriwuryandari, L.; Priantoro, E. A.; Sintawardani, N.

2017-03-01

Approximately, Bandung produces agricultural solid waste of 1549 ton/day. This wastes consist of wet-organic matter and can be used for bio-gas production. The research aimed to apply the available agricultural solid waste for bio-hydrogen. Biogas production was done by a serial of batches anaerobic fermentation using mix-culture bacteria as the active microorganism. Fermentation was carried out inside a 30 L bioreactor at room temperature. The analyzed parameters were of pH, total gas, temperature, and COD. Result showed that from 3 kg/day of organic wastes, various total gases of O2, CH4, H2, CO2, and CnHn,O2 was produced.

Implementation and process analysis of pilot scale multi-phase anaerobic fermentation and digestion of faecal sludge in Ghana.

Science.gov (United States)

Shih, Justin; Fanyin-Martin, Ato; Taher, Edris; Chandran, Kartik

2017-11-06

Background.  In Ghana, faecal sludge (FS) from on-site sanitation facilities is often discharged untreated into the environment, leading to significant insults to environmental and human health. Anaerobic digestion offers an attractive pathway for FS treatment with the concomitant production of energy in the form of methane. Another innovative option includes separating digestion into acidogenesis (production of volatile fatty acids (VFA)) and methanogenesis (production of methane), which could ultimately facilitate the production of an array of biofuels and biochemicals from the VFA. This work describes the development, implementation and modeling based analysis of a novel multiphase anaerobic fermentation-digestion process aimed at FS treatment in Kumasi, Ghana.  Methods.  A pilot-scale anaerobic fermentation process was implemented at the Kumasi Metropolitan Assembly's Oti Sanitary Landfill Site at Adanse Dompoase.  The process consisted of six 10 m reactors in series, which were inoculated with bovine rumen and fed with fecal sludge obtained from public toilets.  The performance of the fermentation process was characterized in terms of both aqueous and gaseous variables representing the conversion of influent organic carbon to VFA as well as CH 4 .  Using the operating data, the first-ever process model for FS fermentation and digestion was developed and calibrated, based on the activated sludge model framework. Results and Conclusions.  This work represents one of the first systematic efforts at integrated FS characterization and process modeling to enable anaerobic fermentation and digestion of FS. It is shown that owing to pre-fermentation of FS in public septage holding tanks, one could employ significantly smaller digesters (lower capital costs) or increased loading capabilities for FS conversion to biogas or VFA. Further, using the first-ever calibrated process model for FS fermentation and digestion presented herein, we expect improved and more

Effect of different ratios of cow manure and corn straw on the mixed anaerobic fermentation rate

Directory of Open Access Journals (Sweden)

Zongshan JIANG

2016-08-01

Full Text Available In order to study the effect of the different ratios on the anaerobic fermentation rate is investigated, and the rate-limiting factors are preliminarily determined, at mesophilic (38±1℃ condition, with anaerobic granular sludge as inoculums, different ratios of cow manure and corn straw are used as substrate for mixed anaerobic fermentation. By measuring daily biogas production, the concentrations of CH4 and CO2 in the marsh gas, TC, the concentration of VFAs and pH value, The results show that under the mixture ratio of 2∶1, the hydrolysis rate constants, cumulative biogas yield and biodegradability CH4 reach their high limits, which are 0.043 7 d^-1, 271.93 mL/g and 71.59%, respectively. Moreover, it is found that the concentration of acetic acid is proportional to the amount of cow manure at the beginning (the first day of mixed fermentation, and the concentration of propionicacid is proportional to the amount of corn straw in medium fermentation stage (the fifth day. In addition, rate-limiting step of biogas production is related to the ratio of cow manure and corn in fermentation material. With the increasing of corn straw proportion, on the 1st day, it tends to hydrolysis acidogenesis; from the 2th day to 15th day, it tends to hydrogen-production acetogenisis; and from the 16th day to 30th day, it is hydrolysis acidogenesis. The paper focuses on the relationship between the ratio of cow manure and corn straw and the rate-limiting step for biogas production, which could provide a theoretical and experimental support for improving the efficiency of biogas production in mixed fermentation.

Effect of high-voltage pulsed electric field (HPEF pretreatment on biogas production rates of hybrid Pennisetum by anaerobic fermentation

Directory of Open Access Journals (Sweden)

Baijuan Wang

2018-02-01

Full Text Available In this paper, the raw materials of hybrid Pennisetum were pretreated in different conditions of high voltage pulsed electric field (HPEF to improve its material utilization ratios and biogas production rates of anaerobic fermentation. Then, anaerobic digestion experiments were conducted within 32 days at moderate temperature (35 °C with TS mass fraction (6%, inoculation rate (20% and initial pH (7.0. It is indicated that compared with the control group, 9 groups of hybrid Pennisetum pretreated by HPEF are obviously superior in gas production efficiency of anaerobic fermentation, and higher in cumulative gas production, peak daily gas production and maximum methane concentration; that the most remarkable stimulation occurs in the HPEF condition of 15 kV/120 Hz/60 min, in that situation, the cumulative gas production in the fermentation period of 32 days is up to 9587 mL, 26.95% higher than that of the control group, the peak daily gas production increases and the range of peak period extends. It is demonstrated that the optimal HPEF pretreatment time is 60 min and three HPEF parameters have a better effect on gas production in the order of voltage > time > frequency; and that the effect degree of treatment parameters on peak daily gas production is voltage, frequency and time in turn. It is concluded that HPEF can improve material utilization ratio and gas production rate of hybrid Pennisetum by anaerobic fermentation and shorten the gas production cycle. By virtue of this physical pretreatment method, the resource of Pennisetum is utilized sufficiently and the classes of energy plants are enlarged effectively. Keywords: Hybrid Pennisetum, Anaerobic fermentation, High voltage pulsed electric field (HPEF, Biogas, Material utilization ratio, Gas generation rate, Model, Stimulation

Production of a ruminant protein supplement by anaerobic fermentation of feedlot waste filtrate

Energy Technology Data Exchange (ETDEWEB)

Reddy, C.A.; Erdman, M.D.

1977-01-01

In studies initiated to develop simple and efficient procedures for the production of feed supplements, it was shown that the filtrate from feedlot wastes diluted with water and filtered could be fermented under anaerobic conditions by mixed rumen bacteria, Lactobacilli, or natural microflora from the feedlot wastes to produce a protein-rich feed supplement. The filtrate is low in carbohydrate and therefore supplemental carbohydrate in the form of whey, molasses, starch from potato processing wastes, or corn starch is necessary. Rigid anaerobic conditions need not be maintained nor must aseptic conditions be observed. (JSR)

Alkaline fermentation of waste sludge causes a significant reduction of antibiotic resistance genes in anaerobic reactors.

Science.gov (United States)

Huang, Haining; Zheng, Xiong; Chen, Yinguang; Liu, Hui; Wan, Rui; Su, Yinglong

2017-02-15

Alkaline fermentation has been reported to be an effective method to recover valuable products from waste sludge. However, to date, the potential effect of alkaline pH on the fate of antibiotic resistance genes (ARGs) during anaerobic fermentation of sludge has never been documented. In this study, the target ARGs in sludge was observed to be removed effectively and stably when sludge was anaerobically fermented at pH10. Compared with the control (without pH adjustment), the abundances of target ARGs at pH10 were reduced by 0.87 (sulI), 1.36 (sulII), 0.42 (tet(O)), 1.11 (tet(Q)), 0.79 (tet(C)) and 1.04 (tet(X)) log units. Further investigations revealed that alkaline fermentation shifted the community structures of potential ARGs hosts. Moreover, alkaline fermentation remarkably decreased the quantities and the ARGs-possessing ability of genetic vectors (plasmid DNA, extracellular DNA and phage DNA), which might limit the transfer of ARGs via conjugation, transformation and transduction. These results suggest that the shifted compositions of gene hosts and restricted gene transfer potential might be the critical reasons for the attenuation of ARGs at pH10. Copyright © 2016 Elsevier B.V. All rights reserved.

Ethanol and anaerobic conditions reversibly inhibit commercial cellulase activity in thermophilic simultaneous saccharification and fermentation (tSSF

Directory of Open Access Journals (Sweden)

Podkaminer Kara K

2012-06-01

Full Text Available Abstract Background A previously developed mathematical model of low solids thermophilic simultaneous saccharification and fermentation (tSSF with Avicel was unable to predict performance at high solids using a commercial cellulase preparation (Spezyme CP and the high ethanol yield Thermoanaerobacterium saccharolyticum strain ALK2. The observed hydrolysis proceeded more slowly than predicted at solids concentrations greater than 50 g/L Avicel. Factors responsible for this inaccuracy were investigated in this study. Results Ethanol dramatically reduced cellulase activity in tSSF. At an Avicel concentration of 20 g/L, the addition of ethanol decreased conversion at 96 hours, from 75% in the absence of added ethanol down to 32% with the addition of 34 g/L initial ethanol. This decrease is much greater than expected based on hydrolysis inhibition results in the absence of a fermenting organism. The enhanced effects of ethanol were attributed to the reduced, anaerobic conditions of tSSF, which were shown to inhibit cellulase activity relative to hydrolysis under aerobic conditions. Cellulose hydrolysis in anaerobic conditions was roughly 30% slower than in the presence of air. However, this anaerobic inhibition was reversed by exposing the cellulase enzymes to air. Conclusion This work demonstrates a previously unrecognized incompatibility of enzymes secreted by an aerobic fungus with the fermentation conditions of an anaerobic bacterium and suggests that enzymes better suited to industrially relevant fermentation conditions would be valuable. The effects observed may be due to inactivation or starvation of oxygen dependent GH61 activity, and manipulation or replacement of this activity may provide an opportunity to improve biomass to fuel process efficiency.

Modular design of metabolic network for robust production of n-butanol from galactose-glucose mixtures.

Science.gov (United States)

Lim, Hyun Gyu; Lim, Jae Hyung; Jung, Gyoo Yeol

2015-01-01

Refactoring microorganisms for efficient production of advanced biofuel such as n-butanol from a mixture of sugars in the cheap feedstock is a prerequisite to achieve economic feasibility in biorefinery. However, production of biofuel from inedible and cheap feedstock is highly challenging due to the slower utilization of biomass-driven sugars, arising from complex assimilation pathway, difficulties in amplification of biosynthetic pathways for heterologous metabolite, and redox imbalance caused by consuming intracellular reducing power to produce quite reduced biofuel. Even with these problems, the microorganisms should show robust production of biofuel to obtain industrial feasibility. Thus, refactoring microorganisms for efficient conversion is highly desirable in biofuel production. In this study, we engineered robust Escherichia coli to accomplish high production of n-butanol from galactose-glucose mixtures via the design of modular pathway, an efficient and systematic way, to reconstruct the entire metabolic pathway with many target genes. Three modular pathways designed using the predictable genetic elements were assembled for efficient galactose utilization, n-butanol production, and redox re-balancing to robustly produce n-butanol from a sugar mixture of galactose and glucose. Specifically, the engineered strain showed dramatically increased n-butanol production (3.3-fold increased to 6.2 g/L after 48-h fermentation) compared to the parental strain (1.9 g/L) in galactose-supplemented medium. Moreover, fermentation with mixtures of galactose and glucose at various ratios from 2:1 to 1:2 confirmed that our engineered strain was able to robustly produce n-butanol regardless of sugar composition with simultaneous utilization of galactose and glucose. Collectively, modular pathway engineering of metabolic network can be an effective approach in strain development for optimal biofuel production with cost-effective fermentable sugars. To the best of our

Elimination patterns of worldwide used sulfonamides and tetracyclines during anaerobic fermentation.

Science.gov (United States)

Spielmeyer, Astrid; Breier, Bettina; Groißmeier, Kathrin; Hamscher, Gerd

2015-10-01

Antibiotics such as sulfonamides and tetracyclines are frequently used in veterinary medicine. Due to incomplete absorption in the animal gut and/or unmetabolized excretion, the substances can enter the environment by using manure as soil fertilizer. The anaerobic fermentation process of biogas plants is discussed as potential sink for antibiotic compounds. However, negative impacts of antibiotics on the fermentation process are suspected. The elimination of sulfadiazine, sulfamethazine, tetracycline and chlortetracycline in semi-continuous lab-scale fermenters was investigated. Both biogas production and methane yield were not negatively affected by concentrations up to 38 mg per kg for sulfonamides and 7 mg per kg for tetracyclines. All substances were partly eliminated with elimination rates between 14% and 89%. Both matrix and structure of the target molecule influenced the elimination rate. Chlortetracycline was mainly transformed into iso-chlortetracycline. In all other cases, the elimination pathways remained undiscovered; however, sorption processes seem to have a negligible impact. Copyright © 2015 Elsevier Ltd. All rights reserved.

In Search of functionality-diversity relationships in anaerobic mixed culture fermentations

International Nuclear Information System (INIS)

Kleerebezem, R.; Temudo, M.; Muyzer Van Loosdrecht, M. C. M.

2009-01-01

Based on the work described in this paper we will postulate that in environmental ecosystems with a weak selective pressure no clear relationship exists between the ecosystem functionality and the microbial diversity and microbial composition. In the past years we have been investigating the anaerobic fermentation of glucose, xylose, and glycerol, and mixtures of these substrates in continuously stirred tank reactors (CSTR) inoculated with an activated sludge characterized by a very rich microbial diversity. (Author)

Volatile fatty acids production from sewage organic matter by combined bioflocculation and anaerobic fermentation

NARCIS (Netherlands)

Khiewwijit, R.; Keesman, K.J.; Rijnaarts, H.H.M.; Temmink, B.G.

2014-01-01

This work aims at exploring the feasibility of a combined process bioflocculation to concentrate sewage organic matter and anaerobic fermentation to produce volatile fatty acids (VFA). Bioflocculation, using a high-loaded aerobic membrane bioreactor (HL-MBR), was operated at an HRT of 1 h and an SRT

Engineering and two-stage evolution of a lignocellulosic hydrolysate-tolerant Saccharomyces cerevisiae strain for anaerobic fermentation of xylose from AFEX pretreated corn stover.

Directory of Open Access Journals (Sweden)

Lucas S Parreiras

Full Text Available The inability of the yeast Saccharomyces cerevisiae to ferment xylose effectively under anaerobic conditions is a major barrier to economical production of lignocellulosic biofuels. Although genetic approaches have enabled engineering of S. cerevisiae to convert xylose efficiently into ethanol in defined lab medium, few strains are able to ferment xylose from lignocellulosic hydrolysates in the absence of oxygen. This limited xylose conversion is believed to result from small molecules generated during biomass pretreatment and hydrolysis, which induce cellular stress and impair metabolism. Here, we describe the development of a xylose-fermenting S. cerevisiae strain with tolerance to a range of pretreated and hydrolyzed lignocellulose, including Ammonia Fiber Expansion (AFEX-pretreated corn stover hydrolysate (ACSH. We genetically engineered a hydrolysate-resistant yeast strain with bacterial xylose isomerase and then applied two separate stages of aerobic and anaerobic directed evolution. The emergent S. cerevisiae strain rapidly converted xylose from lab medium and ACSH to ethanol under strict anaerobic conditions. Metabolomic, genetic and biochemical analyses suggested that a missense mutation in GRE3, which was acquired during the anaerobic evolution, contributed toward improved xylose conversion by reducing intracellular production of xylitol, an inhibitor of xylose isomerase. These results validate our combinatorial approach, which utilized phenotypic strain selection, rational engineering and directed evolution for the generation of a robust S. cerevisiae strain with the ability to ferment xylose anaerobically from ACSH.

Anaerobic fermentation combined with low-temperature thermal pretreatment for phosphorus-accumulating granular sludge: Release of carbon source and phosphorus as well as hydrogen production potential.

Science.gov (United States)

Zou, Jinte; Li, Yongmei

2016-10-01

Releases of organic compounds and phosphorus from phosphorus-accumulating granular sludge (PGS) and phosphorus-accumulating flocculent sludge (PFS) during low-temperature thermal pretreatment and anaerobic fermentation were investigated. Meanwhile, biogas production potential and microbial community structures were explored. The results indicate that much more soluble chemical oxygen demand (SCOD) and phosphorus were released from PGS than from PFS via low-temperature thermal pretreatment because of the higher extracellular polymeric substances (EPS) content in PGS and higher ratio of phosphorus reserved in EPS. Furthermore, PGS contains more anaerobes and dead cells, resulting in much higher SCOD and volatile fatty acids release from PGS than those from PFS during fermentation. PGS fermentation facilitated the n-butyric acid production, and PGS exhibited the hydrogen production potential during fermentation due to the presence of hydrogen-producing bacteria. Therefore, anaerobic fermentation combined with low-temperature thermal pretreatment can facilitate the recovery of carbon and phosphorus as well as producing hydrogen from PGS. Copyright © 2016 Elsevier Ltd. All rights reserved.

EXPLORING OPTIMAL FEED TO MICROBES RATIO FOR ANAEROBIC ACIDOGENIC FERMENTATION OF CASSAVA RESIDUE FROM BREWERY

Directory of Open Access Journals (Sweden)

Xinying Wang,

2012-01-01

Full Text Available Cassava residue from breweries is being generated in large amounts in Guangxi Province of China, and this has potential to cause serious environmental problems if disposed of improperly. Two-stage anaerobic fermentation is a promising method for the treatment of such residue. In this study, the effect of feed to microbes ratio (F/M ratio on the anaerobic acidogenic fermentation of cassava residue was studied to determine the optimal F/M ratio and to maximize the performance in a subsequent methanogenic stage. The experiments were carried out at the F/M ratios of 0.2, 0.61, 1.02, 2.05, 3.07, and 4.09 g cassava-TS/g sludge-VSS in six laboratory-scale, completely stirred, tank reactors (CSTR at mesophilic temperature (35°C. An F/M ratio of 1.02 g cassava-TS/g sludge-VSS resulted in the highest solid removal efficiency and VFA/COD ratio, while starch removal efficiency was still near 100 percent, and acidification was relatively high. As a further benefit, the VFA distribution was more suitable for the subsequent methanogenic fermentation stage.

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)

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.

Linearizing control of continuous anaerobic fermentation processes

Energy Technology Data Exchange (ETDEWEB)

Babary, J.P. [Centre National d`Etudes Spatiales (CNES), 31 - Toulouse (France). Laboratoire d`Analyse et d`Architecture des Systemes; Simeonov, I. [Institute of Microbiology, Bulgarian Academy of Sciences (Bulgaria); Ljubenova, V. [Institute of Control and System Research, BAS (Country unknown/Code not available); Dochain, D. [Universite Catholique de Louvain (UCL), Louvain-la-Neuve (Belgium)

1997-09-01

Biotechnological processes (BTP) involve living organisms. In the anaerobic fermentation (biogas production process) the organic matter is mineralized by microorganisms into biogas (methane and carbon dioxide) in the absence of oxygen. The biogas is an additional energy source. Generally this process is carried out as a continuous BTP. It has been widely used in life process and has been confirmed as a promising method of solving some energy and ecological problems in the agriculture and industry. Because of the very restrictive on-line information the control of this process in continuous mode is often reduced to control of the biogas production rate or the concentration of the polluting organic matter (de-pollution control) at a desired value in the presence of some perturbations. Investigations show that classical linear controllers have good performances only in the linear zone of the strongly non-linear input-output characteristics. More sophisticated robust and with variable structure (VSC) controllers are studied. Due to the strongly non-linear dynamics of the process the performances of the closed loop system may be degrading in this case. The aim of this paper is to investigate different linearizing algorithms for control of a continuous non-linear methane fermentation process using the dilution rate as a control action and taking into account some practical implementation aspects. (authors) 8 refs.

Food Technologies: Fermentation

NARCIS (Netherlands)

Nout, M.J.R.

2014-01-01

Fermentation refers to the use of microorganisms to achieve desirable food properties in the fermented food or beverage. Although the word ‘fermentation’ indicates ‘anaerobic metabolism,’ it is also used in a broader sense to indicate all anaerobic and aerobic microbiological and biochemical

Enhanced biohydrogen production from oat straw co-digested with cow dung / sewage sludge by combined aerobic digestion and anaerobic fermentation

Directory of Open Access Journals (Sweden)

Loretta Li

2016-03-01

Full Text Available Hydrogen was produced from oat straw by combined aerobic and anaerobic fermentation with fungi and cow dung. With aerobic pre-digestion, the maximum hydrogen production rate reached 133 ml/g volatile suspended solids per hour. The maximum hydrogen yield was 71.5 ml/g straw in 6 days by biological process. The lignocellulosic conversion of oak-straw waste was 39%, with the complex component converting 68% of the hemi-cellulose and 61% of the cellulose, but only 34% of lignin conversion. Aerobic pre-digestion by Trichoderma viride and Saccharomyces cerevisiae was significantly effective for lignin degradation.  Combining aerobic and anaerobic fermentation is a promising low-cost efficient and environmentally friendly method, compared with hydrogen fermentation, not only for hydrogen production, but also for converting straw biomass.

Culture-Independent Analyses Reveal Novel Anaerolineaceae as Abundant Primary Fermenters in Anaerobic Digesters Treating Waste Activated Sludge

Directory of Open Access Journals (Sweden)

Simon J. McIlroy

2017-06-01

Full Text Available Anaerobic digestion for biogas production is reliant on the tightly coupled synergistic activities of complex microbial consortia. Members of the uncultured A6 phylotype, within the phylum Chloroflexi, are among the most abundant genus-level-taxa of mesophilic anaerobic digester systems treating primary and surplus sludge from wastewater treatment plants, yet are known only by their 16S rRNA gene sequence. This study applied metagenomics to obtain a complete circular genome (2.57 Mbp from a representative of the A6 taxon. Preliminary annotation of the genome indicates these organisms to be anaerobic chemoorganoheterotrophs with a fermentative metabolism. Given their observed abundance, they are likely important primary fermenters in digester systems. Application of fluorescence in situ hybridisation probes designed in this study revealed their morphology to be short filaments present within the flocs. The A6 were sometimes co-located with the filamentous Archaea Methanosaeta spp. suggesting potential undetermined synergistic relationships. Based on its genome sequence and morphology we propose the species name Brevefilum fermentans gen. nov. sp. nov.

INFLUENCE OF METRONIDAZOLE, CO, CO2, AND METHANOGENS ON THE FERMENTATIVE METABOLISM OF THE ANAEROBIC FUNGUS NEOCALLIMASTIX SP STRAIN L2

NARCIS (Netherlands)

MARVINSIKKEMA, FD; REES, E; KRAAK, MN; GOTTSCHAL, JC; PRINS, RA

The effects of metronidazole, CO, methanogens, and CO, on the fermentation of glucose by the anaerobic fungus Neocallimastix sp. strain L2 were investigated. Both metronidazole and CO caused a shift in the fermentation products from predominantly H-2, acetate, and formate to lactate as the major

Realization of microcontroller-based process control systems examplified on process state monitor for anaerobic biogas fermentation; Realisierung mikrocontrollerbasierter Prozessfuehrungssysteme am Beispiel eines Prozesszustandsmonitors fuer die anaerobe Biogasfermentation

Energy Technology Data Exchange (ETDEWEB)

Patzwahl, S.; Kramer, K.D. [Hochschule Harz, Wernigerode (Germany). Fachbereich Automatisierung und Informatik; Nacke, T. [Institut fuer Bioprozess- und Analysenmesstechnik e.V., Heilbad Heiligenstadt (Germany)

2004-07-01

This paper describes possibilities to realize microcontroller-based process control systems with use strategies of computational intelligence. All design steps are comprised in a design process with direct interface to the process. A further issue is a development system for firmware, which was programmed especially for main steps of the design process. The process of anaerobic fermentation in biogas plants serves as an sample for a control application. By using the design process and the programmed software a process state monitor was developed for this fermentation process. The system is able to classify the process state online in biogas fermentation plants. (orig.)

Influence of sodium chloride, pH, and lactic acid bacteria on anaerobic lactic acid utilization during fermented cucumber spoilage.

Science.gov (United States)

Johanningsmeier, Suzanne D; Franco, Wendy; Perez-Diaz, Ilenys; McFeeters, Roger F

2012-07-01

Cucumbers are preserved commercially by natural fermentations in 5% to 8% sodium chloride (NaCl) brines. Occasionally, fermented cucumbers spoil after the primary fermentation is complete. This spoilage has been characterized by decreases in lactic acid and a rise in brine pH caused by microbial instability. Objectives of this study were to determine the combined effects of NaCl and pH on fermented cucumber spoilage and to determine the ability of lactic acid bacteria (LAB) spoilage isolates to initiate lactic acid degradation in fermented cucumbers. Cucumbers fermented with 0%, 2%, 4%, and 6% NaCl were blended into slurries (FCS) and adjusted to pH 3.2, 3.8, 4.3, and 5.0 prior to centrifugation, sterile-filtration, and inoculation with spoilage organisms. Organic acids and pH were measured initially and after 3 wk, 2, 6, 12, and 18 mo anaerobic incubation at 25 °C. Anaerobic lactic acid degradation occurred in FCS at pH 3.8, 4.3, and 5.0 regardless of NaCl concentration. At pH 3.2, reduced NaCl concentrations resulted in increased susceptibility to spoilage, indicating that the pH limit for lactic acid utilization in reduced NaCl fermented cucumbers is 3.2 or lower. Over 18 mo incubation, only cucumbers fermented with 6% NaCl to pH 3.2 prevented anaerobic lactic acid degradation by spoilage bacteria. Among several LAB species isolated from fermented cucumber spoilage, Lactobacillus buchneri was unique in its ability to metabolize lactic acid in FCS with concurrent increases in acetic acid and 1,2-propanediol. Therefore, L. buchneri may be one of multiple organisms that contribute to development of fermented cucumber spoilage. Microbial spoilage of fermented cucumbers during bulk storage causes economic losses for producers. Current knowledge is insufficient to predict or control these losses. This study demonstrated that in the absence of oxygen, cucumbers fermented with 6% sodium chloride to pH 3.2 were not subject to spoilage. However, lactic acid was degraded

Growth and gas production of a novel obligatory heterofermentative Cheddar cheese nonstarter lactobacilli species on ribose and galactose.

Science.gov (United States)

Ortakci, Fatih; Broadbent, Jeffery R; Oberg, Craig J; McMahon, Donald J

2015-06-01

An obligatory heterofermentative lactic acid bacterium, Lactobacillus wasatchii sp. nov., isolated from gassy Cheddar cheese was studied for growth, gas formation, salt tolerance, and survival against pasteurization treatments at 63°C and 72°C. Initially, Lb. wasatchii was thought to use only ribose as a sugar source and we were interested in whether it could also utilize galactose. We conducted experiments to determine the rate and extent of growth and gas production in carbohydrate-restricted (CR) de Man, Rogosa, and Sharpe (MRS) medium under anaerobic conditions with various combinations of ribose and galactose at 12, 23, and 37°C, with 23°C being the optimum growth temperature of Lb. wasatchii among the 3 temperatures studied. When Lb. wasatchii was grown on ribose (0.1, 0.5, and 1%), maximum specific growth rates (µmax) within each temperature were similar. When galactose was the only sugar, compared with ribose, µmax was 2 to 4 times lower. At all temperatures, the highest final cell densities (optical density at 640 nm) of Lb. wasatchii were achieved in CR-MRS plus 1% ribose, 0.5% ribose and 0.5% galactose, or 1% ribose and 1% galactose. Similar µmax values and final cell densities were achieved when 50% of the ribose in CR-MRS was substituted with galactose. Such enhanced utilization of galactose in the presence of ribose to support bacterial growth has not previously been reported. It appears that Lb. wasatchii co-metabolizes ribose and galactose, utilizing ribose for energy and galactose for other functions such as cell wall biosynthesis. Co-utilization of both sugars could be an adaptation mechanism of Lb. wasatchii to the cheese environment to efficiently ferment available sugars for maximizing metabolism and growth. As expected, gas formation by the heterofermenter was observed only when galactose was present in the medium. Growth experiments with MRS plus 1.5% ribose at pH 5.2 or 6.5 with 0, 1, 2, 3, 4, or 5% NaCl revealed that Lb. wasatchii is

The Lactose and Galactose Content of Cheese Suitable for Galactosaemia: New Analysis.

Science.gov (United States)

Portnoi, P A; MacDonald, A

2016-01-01

The UK Medical Advisory Panel of the Galactosaemia Support Group report the lactose and galactose content of 5 brands of mature Cheddar cheese, Comte and Emmi Emmental fondue mix from 32 cheese samples. The Medical Advisory Panel define suitable cheese in galactosaemia to have a lactose and galactose content consistently below 10 mg/100 g. A total of 32 samples (5 types of mature Cheddar cheese, Comte and "Emmi Swiss Fondue", an emmental fondue mix) were analysed by high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) technology used to perform lactose and galactose analysis. Cheddar cheese types: Valley Spire West Country, Parkham, Lye Cross Vintage, Lye Cross Mature, Tesco West Country Farmhouse Extra Mature and Sainsbury's TTD West Country Farmhouse Extra Mature had a lactose and galactose content consistently below 10 mg/100 g (range <0.05 to 12.65 mg). All Comte samples had a lactose content below the lower limit of detection (<0.05 mg) with galactose content from <0.05 to 1.86 mg/100 g; all samples of Emmi Swiss Fondue had lactose below the lower limit of detection (<0.05 mg) and galactose between 2.19 and 3.04 mg/100 g. All of these cheese types were suitable for inclusion in a low galactose diet for galactosaemia. It is possible that the galactose content of cheese may change over time depending on its processing, fermentation time and packaging techniques.

The contribution of fermentative bacteria and methanogenic archaea to azo dye reduction by a thermophilic anaerobic consortium

NARCIS (Netherlands)

Santos, dos A.B.; Cervantes, F.J.; Madrid, de M.P.; Bok, de F.A.M.; Stams, A.J.M.; Lier, van J.B.

2006-01-01

The contribution of fermentative bacteria and methanogenic archaea to azo dye reduction by a thermophilic anaerobic consortium was studied. Additionally, the effects of different electron-donating substrates and the redox mediator riboflavin on dye reduction were assessed by using either a

Microbiology and physiology of anaerobic fermentation of cellulose. Annual report for 1990, 1992, 1993 and final report

Energy Technology Data Exchange (ETDEWEB)

Ljungdahl, L.G.; Wiegel, J.; Peck, H.D. Jr.; Mortenson, L.E.

1993-08-31

This report focuses on the bioconversion of cellulose to methane by various anaerobes. The structure and enzymatic activity of cellulosome and polycellulosome was studied in Clostridium thermocellum. The extracellular enzymes involved in the degradation of plant material and the physiology of fermentation was investigated in anaerobic fungi. Enzymes dealing with CO, CO{sub 2}, H{sub 2}, CH{sub 3}OH, as well as electron transport and energy generation coupled to the acetyl-CoA autotrophic pathway was studied in acetogenic clostridia.

Dry anaerobic digestion of cow manure and agricultural products in a full-scale plant: Efficiency and comparison with wet fermentation.

Science.gov (United States)

Chiumenti, Alessandro; da Borso, Francesco; Limina, Sonia

2018-01-01

For years, anaerobic digestion processes have been implemented for the management of organic wastes, agricultural residues, and animal manure. Wet anaerobic digestion still represents the most common technology, while dry fermentation, dedicated to the treatment of solid inputs (TS>20%) can be considered as an emerging technology, not in terms of technological maturity, but of diffusion. The first agricultural dry anaerobic digestion plant constructed in Italy was monitored from the start-up, for over a year. The plant was fed with manure and agricultural products, such as corn silage, triticale, ryegrass, alfalfa, and straw. Three Combined Heat and Power units, for a total installed power of 910kW e , converted biogas into thermal and electric energy. The monitoring included the determination of quality and quantity of input feedstocks, of digestate (including recirculation rate), of leachate, biogas quality (CH 4 , CO 2 , H 2 S), biogas yield, energy production, labor requirement for loading, and unloading operations. The results of the monitoring were compared to performance data obtained in several full scale wet digestion plants. The dry fermentation plant revealed a start-up phase that lasted several months, during which the average power resulted in 641kW e (70.4% of nominal power), and the last period the power resulted in 788kW e (86.6% of installed power). Improving the balance of the input, the dry fermentation process demonstrated biogas yields similar to wet anaerobic digestion, congruent to the energy potential of the biomasses used in the process. Furthermore, the operation of the plant required significant man labor, mainly related to loading and unloading of the anaerobic cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biotransformation of aflatoxin B1 and aflatoxin G1 in peanut meal by anaerobic solid fermentation of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus.

Science.gov (United States)

Chen, Yujie; Kong, Qing; Chi, Chen; Shan, Shihua; Guan, Bin

2015-10-15

The purpose of this study was to explore the ability of anaerobic solid fermentation of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus to biotransform aflatoxins in peanut meal. The pH of the peanut meal was adjusted above 10, and then heated for 10 min at 100 °C, 115 °C and 121 °C. The S. thermophilus and L. delbrueckii subsp. bulgaricus were precultured together in MRS broth for 48 h at 37 °C. The heated peanut meal was mixed with precultured MRS broth containing 7.0×10(8) CFU/mL of S. thermophilus and 3.0×10(3) CFU/mL of L. delbrueckii subsp. bulgaricus with the ratio of 1 to 1 (weight to volume) and incubated in anaerobic jars at 37 °C for 3 days. The aflatoxin content in the peanut meal samples was determined by HPLC. The results showed that the peanut meal contained mainly aflatoxin B1 (AFB1) (10.5±0.64 μg/kg) and aflatoxin G1 (AFG1) (18.7±0.55 μg/kg). When heat treatment was combined with anaerobic solid fermentation, the biotransformation rate of aflatoxins in peanut meal could attain 100%. The cytotoxicity of fermented peanut meal to L929 mouse connective tissue fibroblast cells was determined by MTT assay and no significant toxicity was observed in the fermented peanut meal. Furthermore, heat treatment and anaerobic solid fermentation did not change the amino acid concentrations and profile in peanut meal. Copyright © 2015 Elsevier B.V. All rights reserved.

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)

Effect of multiple substrates in ethanol fermentations from cheese whey

Energy Technology Data Exchange (ETDEWEB)

Wang, C J; Jayanata, Y; Bajpai, R K

1987-01-01

Ethanol fermentations from cheese whey by Kluyveromyces marxianus CBS 397 were investigated. Cheese whey, which contains lactose as the major sugar, has been found to have small amounts of glucose and galactose, depending on the source and operating conditions. Fermentation performance was strongly influenced by the presence of glucose and galactose. However, lactose did not significantly affect the cell growth and product formation even at a high concentration. A logistical model was proposed to take into account the effect of lactose. (Refs. 6).

Purification and fermentation characteristics of exopolysaccharide from Fomitopsis castaneus Imaz.

Science.gov (United States)

Guo, Wenkui; Chi, Yujie

2017-12-01

Short-chain fatty acids (SCFAs), which are the end products of carbohydrate fermentation in the gut, mainly contribute to energy metabolism in mammals. The amount of SCFAs produced during fermentation is an important parameter that characterizes the fermentation capacity of a system. This paper reports on the fermentation characteristics of exopolysaccharides (EPS) isolated from Fomitopsis castaneus Imaz, a wood-rot fungal species. We isolated and purified the main EPS fraction by freeze drying and DEAE-Sepharose fast flow chromatography. We then analyzed the monosaccharide composition of EPS. The isolated EPS was mainly composed of glucose, galactose, rhamnose, mannose, and arabinose. The characteristic absorption peaks of sugar esters were also detected. Fresh fecal extracts from healthy adults and children were used as fermentation substrate to simulate the human intestinal environment (anaerobic conditions at 37°C) and study the fermentation characteristics of the purified EPS. Adding the isolated EPS to the fermentation system of the simulated intestinal environment increased the SCFAs content in the fecal extract of adults and children. However, the yield of SCFAs, particularly butyric acid, in the fermentation system of fecal extract in children was higher than that in adults. Furthermore, adding exogenous lactic acid bacteria, such as Enterococcus fecalis and Enterococcus fecium, to the fermentation system effectively increased the SCFAs concentration in the model intestinal system of the children. By contrast, adding E. fecalis, Lactobacillus rhamnosus, and E. fecium increased the content of the produced SCFAs in the system of adults. Those results indicate that EPS isolated from F. castaneus Imaz was effectively fermented in the simulated intestinal environments, and the fermentation capability was enhanced by adding microbial flora. Copyright © 2017 Elsevier B.V. All rights reserved.

Livestock Feed Production from Sago Solid Waste by Pretreatment and Anaerobic Fermentation Process

Directory of Open Access Journals (Sweden)

Sumardiono Siswo

2018-01-01

Full Text Available Food needs in Indonesia is increasing, including beef. Today, Indonesia has problem to do self-sufficiency in beef. The cause of the problem is the quality of local beef is still lower compared with imported beef due to the quality of livestock feed consumed. To increase the quality of livestock is through pretreatment and fermentation. Source of livestock feed that processed is solid sago waste (Arenga microcarpa, because in Indonesia that is relatively abundant and not used optimally. Chemical pretreatment process for delignification is by using NaOH solution. The purposes of this research are to study NaOH pretreatment, the addition of Trichoderma sp, and fermentation time to improve the quality of sago solid waste as livestock feed through anaerobic fermentation. The variables used are addition or without addition (4%w NaOH solution and Trichoderma sp 1%w and fermentation time (7, 14 and 21 days, with the response of crude fiber and protein. The result of this research shows that the pretreatment with soaking of NaOH solution, addition of Trichoderma sp and 14 days of fermentation was more effective to improve the quality of solid sago waste with decrease of crude fiber from 33.37% to 17.36% and increase of crude protein from 4.00% to 7.96%.

Effects of phosphate addition on methane fermentation in the batch and upflow anaerobic sludge blanket (UASB) reactors.

Science.gov (United States)

Suzuki, Sho; Shintani, Masaki; Sanchez, Zoe Kuizon; Kimura, Kohei; Numata, Mitsuru; Yamazoe, Atsushi; Kimbara, Kazuhide

2015-12-01

Ammonia inhibition of methane fermentation is one of the leading causes of failure of anaerobic digestion reactors. In a batch anaerobic digestion reactor with 429 mM NH3-N/L of ammonia, the addition of 25 mM phosphate resulted in an increase in methane production rate. Similar results were obtained with the addition of disodium phosphate in continuous anaerobic digestion using an upflow anaerobic sludge blanket (UASB) reactor. While methane content and production rate decreased in the presence of more than 143 mM NH3-N/L of ammonium chloride in UASB, the addition of 5 mM disodium phosphate suppressed ammonia inhibition at 214 mM NH3-N/L of ammonium chloride. The addition prevented acetate/propionate accumulation, which might be one of the effects of the phosphate on the ammonia inhibition. The effects on the microbial community in the UASB reactor was also assessed, which was composed of Bacteria involved in hydrolysis, acidogenesis, acetogenesis, and dehydrogenation, as well as Archaea carrying out methanogenesis. The change in the microbial community was observed by ammonia inhibition and the addition of phosphate. The change indicates that the suppression of ammonia inhibition by disodium phosphate addition could stimulate the activity of methanogens, reduce shift in bacterial community, and enhance hydrogen-producing bacteria. The addition of phosphate will be an important treatment for future studies of methane fermentation.

Antibiotic Fermentation Broth Treatment by a pilot upflow anaerobic sludge bed reactor and kinetic modeling.

Science.gov (United States)

Coskun, T; Kabuk, H A; Varinca, K B; Debik, E; Durak, I; Kavurt, C

2012-10-01

In this study, an upflow anaerobic sludge blanket (UASB) mesophilic reactor was used to remove antibiotic fermentation broth wastewater. The hydraulic retention time was held constant at 13.3 days. The volumetric organic loading value increased from 0.33 to 7.43 kg(COD)m(-3)d(-1) using antibiotic fermentation broth wastewater gradually diluted with various ratios of domestic wastewater. A COD removal efficiency of 95.7% was obtained with a maximum yield of 3,700 L d(-1) methane gas production. The results of the study were interpreted using the modified Stover-Kincannon, first-order, substrate mass balance and Van der Meer and Heertjes kinetic models. The obtained kinetic coefficients showed that antibiotic fermentation broth wastewater can be successfully treated using a UASB reactor while taking COD removal and methane production into account. Copyright © 2012 Elsevier Ltd. All rights reserved.

Anaerobic Fermentation for Production of Carboxylic Acids as Bulk Chemicals from Renewable Biomass.

Science.gov (United States)

Wang, Jufang; Lin, Meng; Xu, Mengmeng; Yang, Shang-Tian

Biomass represents an abundant carbon-neutral renewable resource which can be converted to bulk chemicals to replace petrochemicals. Carboxylic acids have wide applications in the chemical, food, and pharmaceutical industries. This chapter provides an overview of recent advances and challenges in the industrial production of various types of carboxylic acids, including short-chain fatty acids (acetic, propionic, butyric), hydroxy acids (lactic, 3-hydroxypropionic), dicarboxylic acids (succinic, malic, fumaric, itaconic, adipic, muconic, glucaric), and others (acrylic, citric, gluconic, pyruvic) by anaerobic fermentation. For economic production of these carboxylic acids as bulk chemicals, the fermentation process must have a sufficiently high product titer, productivity and yield, and low impurity acid byproducts to compete with their petrochemical counterparts. System metabolic engineering offers the tools needed to develop novel strains that can meet these process requirements for converting biomass feedstock to the desirable product.

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

Optimizing anaerobic growth rate and fermentation kinetics in Saccharomyces cerevisiae strains expressing Calvin-cycle enzymes for improved ethanol yield

NARCIS (Netherlands)

Papapetridis, I.; Goudriaan, M.; De Keijzer, Nikita A.; van den Broek, M.A.; van Maris, A.J.A.; Pronk, J.T.

2018-01-01

Background: Reduction or elimination of by-product formation is of immediate economic relevance in fermentation processes for industrial bioethanol production with the yeast Saccharomyces cerevisiae. Anaerobic cultures of wild-type S. cerevisiae require formation of glycerol to maintain the

Increasing galactose consumption by Saccharomyces cerevisiae through metabolic engineering of the GAL gene regulatory network

DEFF Research Database (Denmark)

Østergaard, Simon; Olsson, Lisbeth; Johnston, M.

2000-01-01

Increasing the flux through central carbon metabolism is difficult because of rigidity in regulatory structures, at both the genetic and the enzymatic levels. Here we describe metabolic engineering of a regulatory network to obtain a balanced increase in the activity of all the enzymes in the pat...... media. The improved galactose consumption of the gal mutants did not favor biomass formation, but rather caused excessive respiro-fermentative metabolism, with the ethanol production rate increasing linearly with glycolytic flux....... by eliminating three known negative regulators of the GAL system: Gale, Gal80, and Mig1. This led to a 41% increase in flux through the galactose utilization pathway compared with the wild-type strain. This is of significant interest within the field of biotechnology since galactose is present in many industrial...

Fermentation of glycolate by a pure culture of a strictly anaerobic gram-positive bacterium belonging to the family Lachnospiraceae.

Science.gov (United States)

Janssen, Peter H; Hugenholtz, Philip

2003-05-01

The component bacteria of a three-membered mixed culture able to ferment glycolate to acetate, propionate and CO(2) were isolated in pure culture. All three strains were strict anaerobes that, on the basis of comparative 16S rRNA gene sequence analysis, belonged to the order Clostridiales in the phylum Firmicutes (low G+C gram-positive bacteria). Two of the strains were not involved in glycolate metabolism. The third, the glycolate-fermenting strain 19gly4 (DSM 11261), was related to members of the family Lachnospiraceae. The cells of strain 19gly4 were oval- to lemon-shaped, 0.85 microm long and 0.65 microm in diameter, occurring singly, in pairs, or in chains of up to 30 cells. Strain 19gly4 fermented glycolate or fumarate to acetate, succinate, and CO(2). Hydrogen was not formed, and strain 19gly4 was able to grow on glycolate in pure culture without any syntrophic hydrogen transfer and without the use of an external electron acceptor. There was no evidence for homoacetogenic metabolism. This bacterium therefore differs in metabolism from previously reported glycolate-utilising anaerobes.

Development of Galactose Biosensor Based on Functionalized ZnO Nanorods with Galactose Oxidase

Directory of Open Access Journals (Sweden)

K. Khun

2012-01-01

Full Text Available The fabrication of galactose biosensor based on functionalised ZnO nanorods is described. The galactose biosensor was developed by immobilizing galactose oxidase on ZnO nanorods in conjunction with glutaraldehyde as a cross-linker molecule. The IRAS study provided evidence for the interaction of galactose oxidase with the surface of ZnO nanorods. The electromotive force (EMF response of the galactose biosensor was measured by potentiometric method. We observed that the proposed biosensor has a linear detection range over a concentration range from 10 mM to 200 mM with good sensitivity of 89.10±1.23 mV/decade. In addition, the proposed biosensor has shown fast time response of less than 10 s and a good selectivity towards galactose in the presence of common interferents such as ascorbic acid, uric acid, glucose, and magnesium ions. The galactose biosensor based on galactose oxidase immobilized ZnO nanorods has a shelf life more than four weeks.

Production of D-tagatose, a low caloric sweetener during milk fermentation using L-arabinose isomerase.

Science.gov (United States)

Rhimi, Moez; Chouayekh, Hichem; Gouillouard, Isabelle; Maguin, Emmanuelle; Bejar, Samir

2011-02-01

Lactobacillusdelbrueckii subsp. bulgaricus and Streptococcus thermophilus are used for the biotransformation of milk in yoghurt. During milk fermentation, these lactic acid bacteria (LAB) hydrolyze lactose producing a glucose moiety that is further metabolized and a galactose moiety that they are enable to metabolize. We investigated the ability of L. bulgaricus and S. thermophilus strains expressing a heterologous L-arabinose isomerase to convert residual D-galactose to D-tagatose. The Bacillus stearothermophilus US100l-arabinose isomerase (US100l-AI) was expressed in both LAB, using a new shuttle vector where the araA US100 gene is under the control of the strong and constitutive promoter of the L. bulgaricus ATCC 11842 hlbA gene. The production of L-AI by these LAB allowed the bioconversion of D-galactose to D-tagatose during fermentation in laboratory media and milk. We also established that the addition of L-AI to milk also allowed the conversion of D-galactose into D-tagatose during the fermentation process. Copyright © 2010 Elsevier Ltd. All rights reserved.

Enzymes catalyzing pre-hydrolysis facilitated the anaerobic fermentation of waste activated sludge with acidogenic and microbiological perspectives.

Science.gov (United States)

Xin, Xiaodong; He, Junguo; Li, Lin; Qiu, Wei

2018-02-01

This study investigated acidogenic and microbiological perspectives in the anaerobic fermentation (AF) of waste activated sludge (WAS) pre-hydrolyzed by enzymes catalysis. The enzymes catalysis boosted WAS biodegradability dramatically with nearly 8500 mg/L soluble chemical oxygen demand (SCOD) increase just within 4 h. The volatile fatty acids (VFAs) in the acidogenesis were accumulated effectively with over 3200 mg COD/L in 12 d, which reached 0.687 kWh/kg VSS electricity conversion efficiency (2.5 times higher than the control test). The fermentation process favored the compression of fermentative sludge with the distribution spread index (DSI) rising. The core populations of bacteria and archaea shifting enlarged the dissimilarity of communities at different fermentation stages. Increase of community diversity contributed to VFAs accumulation stability. Moreover, the intermediate bacterial community evenness favored VFAs accumulation potentially. The enzymes catalysis might be a promising solution for strengthening VFAs accumulation in the WAS fermentation with boosting the electricity conversion potential. Copyright © 2017 Elsevier Ltd. All rights reserved.

Galactose oxidase immobilized on silica in an analytical determination of galactose-containing carbohydrates.

Science.gov (United States)

Kondakova, Lyudmila; Yanishpolskii, Victor; Tertykh, Valentin; Buglova, Tat'yana

2007-01-01

Galactose oxidase from Fusarium graminearum IMV-1060 adsorbed on, and covalently bound to, silica carriers has been used for analytical determinations of D-galactose and galactose-containing sugars. Using a flowing oxygen electrode of the Clark-type, sensor system for enzymatic analysis of water solutions of galactose-containing carbohydrates was made. Measurements were taken both in the pulse and continuous modes of a substrate flowing through a column with an immobilized biocatalyst. The linear measurement ranges for galactose-containing carbohydrates concentrations were determined.

Lactose fermentation at Camembert, made by classic and stabilised

Directory of Open Access Journals (Sweden)

Bogdan Perko

2002-01-01

Full Text Available In our experiments the fermentation of lactose at Camembert type cheese by classic and stabilised technology was monitored. In each of the two technologies two experiments were made. The difference between these two technologies is in pH level, which drops below 5 by classic technology and remains above 5 by stabilised technology at all times. To achieve the criteria of stabilised technology the fermentation was stopped at a desired level of pH, by dropping the cheese in brine at 14 °C. After salting and moulding cheesewas transferred from the first three experiments into a ripening chamber at 11 °C. With the last experiment (stabilised technology the cheese ripened for 3 days at 5 °C. During ripening process pH dropped below 5 in all experiments. The process of fermentation was performed by the following lactic acid bacteria: Streptococcus thermophilus, Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris. As these lactic acid bacteria ferment differently D-galactose during manufacture and ripening process, the contentof lactose and D-galactose was measured. Based on the results of our research the following conclusion can be made: the action of lactic acid bacteria can not be stropped even at 5 °C. The native microflora, which remains in the milk after thermisation, might be responsible for the fermentation of Dgalactose. It could be possible that the Streptococcus thermophilus enzymes were not inactivated, causing continuation of lactose fermentation even at low temperature. Mesophilic lactococci were inhibited and for that reason Dgalactose accumulated in cheese. Only after cheese were transferred into a ripening chamber at 11 °C and with low lactose concentration in medium left, mesophilic lactococci started to ferment D-galactose.

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.

Association of the golgi UDP-galactose transporter with UDP-galactose: ceramide galactosyltransferase allows UDP-galactose import in the endoplasmic reticulum

NARCIS (Netherlands)

Sprong, H.; Degroote, S.; Nilsson, T.; Kawakita, M.; Ishida, N.; van der Sluijs, P.; van Meer, G.

2003-01-01

UDP-galactose reaches the Golgi lumen through the UDP-galactose transporter (UGT) and is used for the galactosylation of proteins and lipids. Ceramides and diglycerides are galactosylated within the endoplasmic reticulum by the UDP-galactose: ceramide galactosyltransferase. It is not known how

Microbial network for waste activated sludge cascade utilization in an integrated system of microbial electrolysis and anaerobic fermentation

DEFF Research Database (Denmark)

Liu, Wenzong; He, Zhangwei; Yang, Chunxue

2016-01-01

Background: Bioelectrochemical systems have been considered a promising novel technology that shows an enhanced energy recovery, as well as generation of value-added products. A number of recent studies suggested that an enhancement of carbon conversion and biogas production can be achieved....... The characterization of integrated community structure and community shifts is not well understood, however, it starts to attract interest of scientists and engineers. Results: In the present work, energy recovery and WAS conversion are comprehensively affected by typical pretreated biosolid characteristics. We...... investigated the interaction of fermentation communities and electrode respiring communities in an integrated system of WAS fermentation and MEC for hydrogen recovery. A high energy recovery was achieved in the MECs feeding WAS fermentation liquid through alkaline pretreatment. Some anaerobes belonging...

Anaerobic solid state fermentation of cellulosic substrates with possible application to cellulase production

Energy Technology Data Exchange (ETDEWEB)

Vandevoorde, L; Verstraete, W

1987-08-01

A solid state fermentation process was developed for the conversion of straw and cellulose under anaerobic conditions by a mixed culture of cellulolytic and methanogenic organisms. The bioconversion rate and efficiency were compared under mesophilic (35/sup 0/C) and thermophilic (55/sup 0/C) conditions. Cellulolytic activity was assayed in terms of sugar and overall soluble organic matter (chemical oxygen demand, COD) production. Maximum conversion rates were obtained under thermophilic conditions, i.e. 8.4 g and 14.2 g COD/kg.d, respectively, when wheat straw and cellulose were used as substrates. The cellulolytic activity of the reactor contents (23% dry matter), measured under substrate excess conditions, amounted to 50 g COD/kg.d. As a comparison, the activity of rumen contents (15 % dry matter) measured by the same assay amounted to 150 g COD/kg . d. The anaerobic cellulases appeared to be substrate bound. This and the relative low activity levels attained, limit the perspectives of producing cellulase enzymes by this type of process.

The preparation and application of crude cellulase for cellulose-hydrogen production by anaerobic fermentation

Energy Technology Data Exchange (ETDEWEB)

Guo, Yi-Ping; Fan, Yao-Ting; Pan, Chun-Mei; Hou, Hong-Wei [Department of Chemistry, Zhengzhou University, Zhengzhou, Henan 450052 (China); Fan, Shao-Qun [Department of Chemistry, Zhengzhou University, Zhengzhou, Henan 450052 (China); Beijing Alcatel-Lucent R and D Center, Beijing, 100102 (China)

2010-01-15

Strategies were adopted to cost-efficiently produce cellulose-hydrogen by anaerobic fermentation in this paper. First, cellulase used for hydrolyzing cellulose was prepared by solid-state fermentation (SSF) on cheap biomass from Trichoderma viride. Several cultural conditions for cellulase production on cheap biomass such as moisture content, inoculum size and culture time were studied. And the components of solid-state medium were optimized using statistical methods to further improve cellulase capability. Second, the crude cellulase was applied to cellulose-hydrogen process directly. The maximal hydrogen yield of 122 ml/g-TVS was obtained at the substrate concentration of 20 g/L and cultured time of 53 h. The value was about 45-fold than that of raw corn stalk wastes. The hydrogen content in the biogas was 44-57%(v/v) and there was no significant methane gas observed. (author)

Production of citric acid using its extraction wastewater treated by anaerobic digestion and ion exchange in an integrated citric acid-methane fermentation process.

Science.gov (United States)

Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

2014-08-01

In order to solve the problem of extraction wastewater pollution in citric acid industry, an integrated citric acid-methane fermentation process is proposed in this study. Extraction wastewater was treated by mesophilic anaerobic digestion and then used to make mash for the next batch of citric acid fermentation. The recycling process was done for seven batches. Citric acid production (82.4 g/L on average) decreased by 34.1 % in the recycling batches (2nd-7th) compared with the first batch. And the residual reducing sugar exceeded 40 g/L on average in the recycling batches. Pigment substances, acetic acid, ammonium, and metal ions in anaerobic digestion effluent (ADE) were considered to be the inhibitors, and their effects on the fermentation were studied. Results indicated that ammonium, Na(+) and K(+) in the ADE significantly inhibited citric acid fermentation. Therefore, the ADE was treated by acidic cation exchange resin prior to reuse to make mash for citric acid fermentation. The recycling process was performed for ten batches, and citric acid productions in the recycling batches were 126.6 g/L on average, increasing by 1.7 % compared with the first batch. This process could eliminate extraction wastewater discharge and reduce water resource consumption.

BIOESTABILIZATION ANAEROBIC SOLID WASTE ORGANIC:QUANTITATIVE ASPECTS

Directory of Open Access Journals (Sweden)

Valderi Duarte Leite

2015-01-01

Full Text Available It is estimated that in Brazil, the municipal solid waste produced are constituted on average 55% of fermentable organic solid waste and that this quantity can be applied in aerobic or anaerobic stabilization process. Anaerobic digestion is an important alternative for the treatment of different types of potentially fermentable waste, considering providing an alternative source of energy that can be used to replace fossil fuels. To perform the experimental part of this work was constructed and monitored an experimental system consisting of an anaerobic batch reactor, shredding unit of fermentable organic wastes and additional devices. Fermentable organic wastes consisted of leftover fruits and vegetables and were listed in EMPASA (Paraibana Company of Food and Agricultural Services, located in the city of Campina Grande- PB. The residues were collected and transported to the Experimental Station Biological Sewage Treatment (EXTRABES where they were processed and used for substrate preparation. The substrate consisted of a mixture of fermentable organic waste, more anaerobic sewage sludge in the proportion of 80 and 20 % respectively. In the specific case of this study, it was found that 1m3 of substrate concentration of total COD equal to 169 g L-1, considering the reactor efficiency equal to 80 %, the production of CH4 would be approximately 47.25 Nm3 CH4. Therefore, fermentable organic waste, when subjected to anaerobic treatment process produces a quantity of methane gas in addition to the partially biostabilized compound may be applied as a soil conditioning agent.

Fermentative Hydrogen Production from Combination of Tofu processing and anaerobic digester sludge wastes using a microbial consortium

International Nuclear Information System (INIS)

You-Kwan, O.; Mi-Sun, K.

2009-01-01

The combination of Tofu manufacturing waste and anaerobic digester sludge was studied for fermentative H 2 production in batch and continuous modes using a mixed culture originated from sewage. In order to increase the solubilization of organic substrates from Tofu waste, various pretreatments including heat-treatment, acid/alkali treatment, and sonication were examined alone or in combination with others. (Author)

The presence of bromuconazole fungicide pollutant in organic waste anaerobic fermentation

Science.gov (United States)

Hariyadi, H. R.

2017-03-01

The presence of bromuconazole fungicide pollutant in organic waste anaerobic fermentation was carried out as well as the influence phenol and benzoate, and biodegradation of bromuconazole. Bromuconazole is a fungicide effective against Ascomycetes, Basidiomycetes and fungi imperfecti in cereals, grapes, top fruits and vegetables. It is also effective against Alternaria and Fusarium sp. The remaining fungicide in leaves might contaminates landfill. One month of organic waste added with bromuconazole was anaerobically incubated in 500 mL bottles at 30°C without shaking in dark room. High-Performance Liquid Chromatography (HPLC) with UV detector and a 100 RP 185μm Lichrosphere column was used to determine bromuconazole concentration. Methane content was determined by Gas Chromatography (GC) method equipped with a flame ionization detector and a metal column packed with 5% neopentyl glycol sebacate and 1% H3PO4 on Chromosorb W-AW (mesh 80-100). After incubation for 225 days, bromuconazole of 200 mg/L inhibited the production of methane (99.5 mM) significantly, but did not inhibit the production of volatile fatty acids. The addition of 100 mg/L phenol or 146 mg/L benzoate increased the production of methane, 143 mM and 135.2 mM, respectively compared with control (121.8 mM). In anaerobic conditions, the presence of toxic pollutants such as fungicide bromuconazole in landfills sites may cause further problems with the accumulation of volatile fatty acids in leachate. Further study to determine the threshold, the presence of bromconazole in low concentration (less than 200 mg/L) on the methane production is recommended.

Potential biodiesel and biogas production from corncob by anaerobic fermentation and black soldier fly.

Science.gov (United States)

Li, Wu; Li, Qing; Zheng, Longyu; Wang, Yuanyuan; Zhang, Jibin; Yu, Ziniu; Zhang, Yanlin

2015-10-01

Bioenergy has become attractive as alternatives of gradually exhausted fossil fuel. Obtaining high grade bioenergy from lignocellulose is attractive that can gradually meet the demand. This study reported biogas and biodiesel were produced from corncob by a two-step bioprocess, biogas was produced from corncob by anaerobic fermentation, then biogas residue was converted by black soldier fly larvae, and then biodiesel was produced from larvae grease. 86.70 L biogas was obtained from 400 g corncob with the accumulation of biogas yield of 220.71 mL/g VS(added) by anaerobic digestion. Besides, 3.17 g of biodiesel was produced from grease after inoculating black soldier fly larvae into 400 g biogas residue. Meanwhile, the results showed that the addition of black soldier fly larvae could be effective for the degradation of lignocellulose and the accumulation of grease. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

Lactose uptake driven by galactose efflux in Streptococcus thermophilus: Evidence for a galactose-lactose antiporter

International Nuclear Information System (INIS)

Hutkins, R.W.; Ponne, C.

1991-01-01

Galactose-nonfermenting (Gal - ) Streptococcus thermophilus TS2 releases galactose into the extracellular medium when grown in medium containing excess lactose. Starved and de-energized Gal - cells, however, could be loaded with galactose to levels approximately equal to the extracellular concentration (0 to 50 mM). When loaded cells were separated from the medium and resuspended in fresh broth containing 5 mM lactose, galactose efflux occurred. De-energized, galactose-loaded cells, resuspended in buffer or medium, accumulated [ 14 C]lactose at a greater rate and to significantly higher intracellular concentrations than unloaded cells. Uptake of lactose by loaded cells was inhibited more than that by unloaded cells in the presence of extracellular galactose, indicating that a galactose gradient was involved in the exchange system. When de-energized, galactose-loaded cells were resuspended in carbohydrate-free medium at pH 6.7, a proton motive force (Δp) of 86 to 90 mV was formed, whereas de-energized, nonloaded cells maintained a Δp of about 56 mV. However, uptake of lactose by loaded cells occurred when the proton motive force was abolished by the addition of an uncoupler or in the presence of a proton-translocating ATPase inhibitor. These results support the hypothesis that galactose efflux in Gal - S. thermophilus is electrogenic and that the exchange reaction (lactose uptake and galactose efflux) probably occurs via an antiporter system

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.

Biostimulation of anaerobic BTEX biodegradation under fermentative methanogenic conditions at source-zone groundwater contaminated with a biodiesel blend (B20).

Science.gov (United States)

Ramos, Débora Toledo; da Silva, Márcio Luis Busi; Chiaranda, Helen Simone; Alvarez, Pedro J J; Corseuil, Henry Xavier

2013-06-01

Field experiments were conducted to assess the potential for anaerobic biostimulation to enhance BTEX biodegradation under fermentative methanogenic conditions in groundwater impacted by a biodiesel blend (B20, consisting of 20 % v/v biodiesel and 80 % v/v diesel). B20 (100 L) was released at each of two plots through an area of 1 m(2) that was excavated down to the water table, 1.6 m below ground surface. One release was biostimulated with ammonium acetate, which was added weekly through injection wells near the source zone over 15 months. The other release was not biostimulated and served as a baseline control simulating natural attenuation. Ammonium acetate addition stimulated the development of strongly anaerobic conditions, as indicated by near-saturation methane concentrations. BTEX removal began within 8 months in the biostimulated source zone, but not in the natural attenuation control, where BTEX concentrations were still increasing (due to source dissolution) 2 years after the release. Phylogenetic analysis using quantitative PCR indicated an increase in concentration and relative abundance of Archaea (Crenarchaeota and Euryarchaeota), Geobacteraceae (Geobacter and Pelobacter spp.) and sulfate-reducing bacteria (Desulfovibrio, Desulfomicrobium, Desulfuromusa, and Desulfuromonas) in the biostimulated plot relative to the control. Apparently, biostimulation fortuitously enhanced the growth of putative anaerobic BTEX degraders and associated commensal microorganisms that consume acetate and H2, and enhance the thermodynamic feasibility of BTEX fermentation. This is the first field study to suggest that anaerobic-methanogenic biostimulation could enhance source zone bioremediation of groundwater aquifers impacted by biodiesel blends.

Preparation of D-[U-14C]galactose and α-D-[U-14C]galactose-1-phosphate

International Nuclear Information System (INIS)

Kolina, J.; Hromadkova, B.

1989-01-01

Optically pure D-[U- 14 C]galactose was prepared on a preparatory scale using the galactokinase enzyme. The suggested procedure allows to also prepare a α-D-[U- 14 C]galactose-1-phosphate and L-[U- 14 ]galactose giving good yield. The experiments proved that the raw fraction isolated from yeast of the Kluyveromyces fragilis strain or the Kluyveromyces lactis strain shows sufficient activity. Phosphorylation of D-[U- 14 C]galactose practically terminates after 30 mins of incubation. DL-[U- 14 C]galactose isolated using preparatory paper chromatography from the acid hydrolyzate of [U- 14 C] polysaccharide is a satisfactory radioactive precursor. The developed preparation procedure theoretically contributed towards the further elucidation of the problem of the proportional representation of galactose stereo-isomers in extracellular polysaccharide isolated from red algae. In this respect data in the literature differ and some sources state a significantly higher propertion of L-galactose. The experiments showed that [U- 14 C] polysaccharide isolated from the red algae Porphyridium cruentum prevalently contains D-[U- 14 C]galactose, which confirms the process of enzyme reaction. (author). 1 tab., 4 refs

Data Pre-Processing Method to Remove Interference of Gas Bubbles and Cell Clusters During Anaerobic and Aerobic Yeast Fermentations in a Stirred Tank Bioreactor

Science.gov (United States)

Princz, S.; Wenzel, U.; Miller, R.; Hessling, M.

2014-11-01

One aerobic and four anaerobic batch fermentations of the yeast Saccharomyces cerevisiae were conducted in a stirred bioreactor and monitored inline by NIR spectroscopy and a transflectance dip probe. From the acquired NIR spectra, chemometric partial least squares regression (PLSR) models for predicting biomass, glucose and ethanol were constructed. The spectra were directly measured in the fermentation broth and successfully inspected for adulteration using our novel data pre-processing method. These adulterations manifested as strong fluctuations in the shape and offset of the absorption spectra. They resulted from cells, cell clusters, or gas bubbles intercepting the optical path of the dip probe. In the proposed data pre-processing method, adulterated signals are removed by passing the time-scanned non-averaged spectra through two filter algorithms with a 5% quantile cutoff. The filtered spectra containing meaningful data are then averaged. A second step checks whether the whole time scan is analyzable. If true, the average is calculated and used to prepare the PLSR models. This new method distinctly improved the prediction results. To dissociate possible correlations between analyte concentrations, such as glucose and ethanol, the feeding analytes were alternately supplied at different concentrations (spiking) at the end of the four anaerobic fermentations. This procedure yielded low-error (anaerobic) PLSR models for predicting analyte concentrations of 0.31 g/l for biomass, 3.41 g/l for glucose, and 2.17 g/l for ethanol. The maximum concentrations were 14 g/l biomass, 167 g/l glucose, and 80 g/l ethanol. Data from the aerobic fermentation, carried out under high agitation and high aeration, were incorporated to realize combined PLSR models, which have not been previously reported to our knowledge.

Study on Release Characteristics and Recovery of Nitrogen and Phosphorus during the Anaerobic Fermentation of Excess Sludge

Science.gov (United States)

Qin, Yuqian; Hu, Shulong

2018-01-01

Ammonia nitrogen and phosphate are produced from activated excess sludge under anaerobic conditions,and will cause eutrophication upon release to the environment. A study of sludge from a eutrophication was carried out, to obtain knowledge of the nitrogen and phosphorus release patterns of the excess sludge during anaerobic fermentation and the recycling efficiency of both nitrogen and phosphorus, by adding magnesium salt and alkali solution to the supernatant liquors. The results showed that the concentration of ammonia nitrogen and phosphate of the supernatant liquors continued to increase during the process of anaerobic digestion, and both reached a maximum in 12 days, at 41.56mg / L and 47.02 mg / L respectively. By adding magnesium salt to the supernatant with c(Mg): c(P) = 1.1:1, adjusting pH value to 9.0 ∼ 9.5, phosphorus recovery rate reached up to 95.0%, while the recovery rate of ammonia was 47.4%, resulting in the formation of a sediment of magnesium ammonium phosphate, or MAP, which may he used as a high-quality fertilizer.

In vitro metabolism of radiolabeled carbohydrates by protective cecal anaerobic bacteria.

Science.gov (United States)

Hume, M E; Beier, R C; Hinton, A; Scanlan, C M; Corrier, D E; Peterson, D V; DeLoach, J R

1993-12-01

Cecal anaerobic bacteria from adult broilers were cultured in media containing .25% glucose or .25% lactose. Media also contained either [14C]-labeled lactose, glucose, galactose, or lactic acid as metabolic tracers. Cultures were analyzed at 4, 8, and 12 h for pH, radiolabeled and unlabeled volatile fatty acids, and lactic acid. The pH values of cultures containing .25% lactose were significantly (P galactose, lactose > glucose. The volatile fatty acids in which radiolabel was most concentrated were acetic acid, propionic acid, or butyric acid.

Synergetic effect of pH and biochemical components on bacterial diversity during mesophilic anaerobic fermentation of biomass-origin waste.

Science.gov (United States)

Lü, F; Shao, L M; Bru, V; Godon, J J; He, P J

2009-02-01

To investigate the synergetic effect of pH and biochemical components on bacterial community structure during mesophilic anaerobic degradation of solid wastes with different origins, and under acidic or neutral conditions. The bacterial community in 16 samples of solid wastes with different biochemical compositions and origins was evaluated during mesophilic anaerobic degradation at acidic and neutral pH. Denaturing gradient gel electrophoresis (DGGE) and single-strand conformation polymorphism (SSCP) were used to compare the communities. Multivariate analysis of the DGGE and SSCP results revealed that most of the dominant microbes were dependent on the content of easily degradable carbohydrates in the samples. Furthermore, the dominant microbes were divided into two types, those that preferred an acid environment and those that preferred a neutral environment. A shift in pH was found to change their preference for medium substrates. Although most of the substrates with similar origin and biochemical composition had similar microbial diversity during fermentation, some microbes were found only in substrates with specific origins. For example, two microbes were only found in substrate that contained lignocellulose and animal protein without starch. These microbes were related to micro-organisms that are found in swine manure, as well as in other intestinal or oral niches. In addition, the distribution of fermentation products was less sensitive to the changes in pH and biochemical components than the microbial community. Bacterial diversity during anaerobic degradation of organic wastes was affected by both pH and biochemical components; however, pH exerted a greater effect. The results of this study reveal that control of pH may be an effective method to produce a stable bacterial community and relatively similar product distribution during anaerobic digestion of waste, regardless of variation in the waste feedstocks.

Novel process combining anaerobic-aerobic digestion and ion exchange resin for full recycling of cassava stillage in ethanol fermentation.

Science.gov (United States)

Yang, Xinchao; Wang, Ke; Wang, Huijun; Zhang, Jianhua; Mao, Zhonggui

2017-04-01

A novel cleaner ethanol production process has been developed. Thin stillage is treated initially by anaerobic digestion followed by aerobic digestion and then further treated by chloride anion exchange resin. This allows the fully-digested and resin-treated stillage to be completely recycled for use as process water in the next ethanol fermentation batch, which eliminates wastewater discharges and minimizes consumption of fresh water. The method was evaluated at the laboratory scale. Process parameters were very similar to those found using tap water. Maximal ethanol production rate in the fully-recycled stillage was 0.9g/L/h, which was similar to the 0.9g/L/h found with the tap water control. The consumption of fresh water was reduced from 4.1L/L (fresh water/ethanol) to zero. Compared with anaerobically-aerobically digested stillage which had not been treated with resin, the fermentation time was reduced by 28% (from 72h to 52h) and reached the level achieved with tap water. This novel process can assist in sustainable development of the ethanol industry. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

Microbial network for waste activated sludge cascade utilization in an integrated system of microbial electrolysis and anaerobic fermentation

DEFF Research Database (Denmark)

Liu, Wenzong; He, Zhangwei; Yang, Chunxue

2016-01-01

in an integrated system of microbial electrolysis cell (MEC) and anaerobic digestion (AD) for waste activated sludge (WAS). Microbial communities in integrated system would build a thorough energetic and metabolic interaction network regarding fermentation communities and electrode respiring communities...... to Firmicutes (Acetoanaerobium, Acetobacterium, and Fusibacter) showed synergistic relationship with exoelectrogensin the degradation of complex organic matter or recycling of MEC products (H2). High protein and polysaccharide but low fatty acid content led to the dominance of Proteiniclasticum...... biofilm. The overall performance of WAS cascade utilization was substantially related to the microbial community structures, which in turn depended on the initial pretreatment to enhance WAS fermentation. It is worth noting that species in AD and MEC communities are able to build complex networks...

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.

Succinic acid production by escherichia coli under anaerobic fermentation

International Nuclear Information System (INIS)

El Shafey, H.M.; Meleigy, S.A.

2009-01-01

The effect of alteration of growth conditions, addition of different sodium salts, and irradiation by gamma rays on succinic acid production by E. coli was studied. Twenty one isolates were obtained from buffalo's rumen, and anaerobic screening of the isolated bacterial strains showed the abilities of seventeen strains to produce succinic acid. The two bacterial strains having highest succinic acid production were identified as escherichia coli SP9 and SP16, and were selected for further studies. Results showed that growth conditions yielded highest succinic acid production for the two isolates were: 72 hours incubation, 37 degree c incubation temperature, initial ph of the fermentation medium 6.0,and 3% (v/v)inoculum size. Addition of 5 mm of nine different sodium salts to the fermentation medium showed stimulating effect on succinic acid production of the nine tried sodium salts, sodium carbonate was found to have the highest enhancing effect, especially if used at 15 mm concentration. Gamma irradiation doses tried were in the range of (0.25-1.50 kGy). An enhancing effect on succinic acid production was shown in the range of 0.25-0.75 kGy with a maximal production at 0.75 kGy (giving 8.36% increase) for e.coli SP9, and in the range of 0.25-1.00 kGy with a maximal production at 1.0 kGy (7.60% increase) for e.coli SP16. higher gamma doses led to a decrease in the enhancing effect. An overall increase in the succinic acid yield of 79.45% and 94.26% for e. coli SP9 and SP16, respectively, was achieved in implicating all optimized factors for succinic acid production in one time

Biological upgrading of volatile fatty acids, key intermediates for the valorization of biowaste through dark anaerobic fermentation.

Science.gov (United States)

Singhania, Reeta Rani; Patel, Anil Kumar; Christophe, Gwendoline; Fontanille, Pierre; Larroche, Christian

2013-10-01

VFAs can be obtained from lignocellulosic agro-industrial wastes, sludge, and various biodegradable organic wastes as key intermediates through dark fermentation processes and synthesized through chemical route also. They are building blocks of several organic compounds viz. alcohol, aldehyde, ketones, esters and olefins. These can serve as alternate carbon source for microbial biolipid, biohydrogen, microbial fuel cells productions, methanisation, and for denitrification. Organic wastes are the substrate for VFA platform that is of zero or even negative cost, giving VFA as intermediate product but their separation from the fermentation broth is still a challenge; however, several separation technologies have been developed, membrane separation being the most suitable one. These aspects will be reviewed and results obtained during anaerobic treatment of slaughterhouse wastes with further utilisation of volatile fatty acids for yeast cultivation have been discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Comment on 'evaluation of dechlorination mechanisms during anaerobic fermentation of blached kraft mill effluent by W.J. Parker, E.R. Hall and G.J. Farquhar'

Digital Repository Service at National Institute of Oceanography (India)

Sarkar, A.

Comment on "Evaluation of dechlorination mechanisms during anaerobic fermentation of bleached kraft mill effluent", is put forth. The data reproduced in Table 1 does not seem to be authentic as the method of preprationo of the chlorinated organic...

In vitro fermentation of mulberry fruit polysaccharides by human fecal inocula and impact on microbiota.

Science.gov (United States)

Chen, Chun; Huang, Qiang; Fu, Xiong; Liu, Rui Hai

2016-11-09

This study investigated the in vitro fermentation of polysaccharides from Morus alba L., the contribution of its carbohydrates to the fermentation, and the effect on the composition of gut microbiota. Over 48 h of fermentation, the pH value in the fecal culture decreased from 7.12 to 6.14, and the total short chain fatty acids (SCFA) and acetic, propionic, and butyric acids all significantly increased. After 48 h of fermentation, 45.36 ± 1.36% of the total carbohydrates in the polysaccharide, including 35.72 ± 1.51% of arabinose, 23.1 ± 1.19% of galactose, 41.43 ± 1.52% of glucose, 26.36 ± 1.93% of rhamnose and 65.57 ± 1.07% of galacturic acid, were consumed. The increase in acetic and butyric acids was primarily due to the fermentation of galactose and galacturonic acid in the polysaccharide, while the increase in propionic acid resulted mainly from the fermentation of arabinose and glucose. In addition, the polysaccharide could modulate the gut microbiota composition by increasing the Bacteroidetes population and decreasing the Firmicutes population. The results may facilitate the development of food products known as prebiotics, aimed at improving gastrointestinal health.

Full-scale production of VFAs from sewage sludge by anaerobic alkaline fermentation to improve biological nutrients removal in domestic wastewater.

Science.gov (United States)

Liu, He; Han, Peng; Liu, Hongbo; Zhou, Guangjie; Fu, Bo; Zheng, Zhiyong

2018-07-01

A full-scale project of thermal-alkaline pretreatment and alkaline fermentation of sewage sludge was built to produce volatile fatty acids (VFAs) which was then used as external carbon source for improving biological nitrogen and phosphorus removals (BNPR) in wastewater plant. Results showed this project had efficient and stable performances in VFA production, sludge reduce and BNPR. Hydrolysis rate in pretreatment, VFAs yield in fermentation and total VS reduction reached 68.7%, 261.32 mg COD/g VSS and 54.19%, respectively. Moreover, fermentation liquid with VFA presented similar efficiency as acetic acid in enhancing BNPR, obtaining removal efficiencies of nitrogen and phosphorus up to 72.39% and 89.65%, respectively. Finally, the project also presented greater economic advantage than traditional processes, and the net profits for VFAs and biogas productions are 9.12 and 3.71 USD/m 3 sludge, respectively. Long-term operation indicated that anaerobic alkaline fermentation for VFAs production is technically and economically feasible for sludge carbon recovery. Copyright © 2018 Elsevier Ltd. All rights reserved.

Sequential high gravity ethanol fermentation and anaerobic digestion of steam explosion and organosolv pretreated corn stover.

Science.gov (United States)

Katsimpouras, Constantinos; Zacharopoulou, Maria; Matsakas, Leonidas; Rova, Ulrika; Christakopoulos, Paul; Topakas, Evangelos

2017-11-01

The present work investigates the suitability of pretreated corn stover (CS) to serve as feedstock for high gravity (HG) ethanol production at solids-content of 24wt%. Steam explosion, with and without the addition of H 2 SO 4 , and organosolv pretreated CS samples underwent a liquefaction/saccharification step followed by simultaneous saccharification and fermentation (SSF). Maximum ethanol concentration of ca. 76g/L (78.3% ethanol yield) was obtained from steam exploded CS (SECS) with 0.2% H 2 SO 4 . Organosolv pretreated CS (OCS) also resulted in high ethanol concentration of ca. 65g/L (62.3% ethanol yield). Moreover, methane production through anaerobic digestion (AD) was conducted from fermentation residues and resulted in maximum methane yields of ca. 120 and 69mL/g volatile solids (VS) for SECS and OCS samples, respectively. The results indicated that the implementation of a liquefaction/saccharification step before SSF employing a liquefaction reactor seemed to handle HG conditions adequately. Copyright © 2017 Elsevier Ltd. All rights reserved.

Thermodynamic analysis of fermentation and anaerobic growth of baker's yeast for ethanol production.

Science.gov (United States)

Teh, Kwee-Yan; Lutz, Andrew E

2010-05-17

Thermodynamic concepts have been used in the past to predict microbial growth yield. This may be the key consideration in many industrial biotechnology applications. It is not the case, however, in the context of ethanol fuel production. In this paper, we examine the thermodynamics of fermentation and concomitant growth of baker's yeast in continuous culture experiments under anaerobic, glucose-limited conditions, with emphasis on the yield and efficiency of bio-ethanol production. We find that anaerobic metabolism of yeast is very efficient; the process retains more than 90% of the maximum work that could be extracted from the growth medium supplied to the chemostat reactor. Yeast cells and other metabolic by-products are also formed, which reduces the glucose-to-ethanol conversion efficiency to less than 75%. Varying the specific ATP consumption rate, which is the fundamental parameter in this paper for modeling the energy demands of cell growth, shows the usual trade-off between ethanol production and biomass yield. The minimum ATP consumption rate required for synthesizing cell materials leads to biomass yield and Gibbs energy dissipation limits that are much more severe than those imposed by mass balance and thermodynamic equilibrium constraints. 2010 Elsevier B.V. All rights reserved.

Anaerobic energy metabolism in unicellular photosynthetic eukaryotes.

Science.gov (United States)

Atteia, Ariane; van Lis, Robert; Tielens, Aloysius G M; Martin, William F

2013-02-01

Anaerobic metabolic pathways allow unicellular organisms to tolerate or colonize anoxic environments. Over the past ten years, genome sequencing projects have brought a new light on the extent of anaerobic metabolism in eukaryotes. A surprising development has been that free-living unicellular algae capable of photoautotrophic lifestyle are, in terms of their enzymatic repertoire, among the best equipped eukaryotes known when it comes to anaerobic energy metabolism. Some of these algae are marine organisms, common in the oceans, others are more typically soil inhabitants. All these species are important from the ecological (O(2)/CO(2) budget), biotechnological, and evolutionary perspectives. In the unicellular algae surveyed here, mixed-acid type fermentations are widespread while anaerobic respiration, which is more typical of eukaryotic heterotrophs, appears to be rare. The presence of a core anaerobic metabolism among the algae provides insights into its evolutionary origin, which traces to the eukaryote common ancestor. The predicted fermentative enzymes often exhibit an amino acid extension at the N-terminus, suggesting that these proteins might be compartmentalized in the cell, likely in the chloroplast or the mitochondrion. The green algae Chlamydomonas reinhardtii and Chlorella NC64 have the most extended set of fermentative enzymes reported so far. Among the eukaryotes with secondary plastids, the diatom Thalassiosira pseudonana has the most pronounced anaerobic capabilities as yet. From the standpoints of genomic, transcriptomic, and biochemical studies, anaerobic energy metabolism in C. reinhardtii remains the best characterized among photosynthetic protists. This article is part of a Special Issue entitled: The evolutionary aspects of bioenergetic systems. Copyright © 2012 Elsevier B.V. All rights reserved.

Enzymatic conversion of D-galactose to D-tagatose: heterologous expression and characterisation of a thermostable L-arabinose isomerase from Thermoanaerobacter mathranii.

Science.gov (United States)

Jørgensen, F; Hansen, O C; Stougaard, P

2004-06-01

The ability to convert D-galactose into D-tagatose was compared among a number of bacterial L-arabinose isomerases ( araA). One of the most efficient enzymes, from the anaerobic thermophilic bacterium Thermoanaerobacter mathranii, was produced heterologously in Escherichia coli and characterised. Amino acid sequence comparisons indicated that this enzyme is only distantly related to the group of previously known araA sequences in which the sequence similarity is evident. The substrate specificity and the Michaelis-Menten constants of the enzyme determined with L-arabinose, D-galactose and D-fucose also indicated that this enzyme is an unusual, versatile L-arabinose isomerase which is able to isomerise structurally related sugars. The enzyme was immobilised and used for production of D-tagatose at 65 degrees C. Starting from a 30% solution of D-galactose, the yield of D-tagatose was 42% and no sugars other than D-tagatose and D-galactose were detected. Direct conversion of lactose to D-tagatose in a single reactor was demonstrated using a thermostable beta-galactosidase together with the thermostable L-arabinose isomerase. The two enzymes were also successfully combined with a commercially available glucose isomerase for conversion of lactose into a sweetening mixture comprising lactose, glucose, galactose, fructose and tagatose.

Effect of propionic acid on citric acid fermentation in an integrated citric acid-methane fermentation process.

Science.gov (United States)

Xu, Jian; Bao, Jia-Wei; Su, Xian-Feng; Zhang, Hong-Jian; Zeng, Xin; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

2016-03-01

In this study, an integrated citric acid-methane fermentation process was established to solve the problem of wastewater treatment in citric acid production. Citric acid wastewater was treated through anaerobic digestion and then the anaerobic digestion effluent (ADE) was further treated and recycled for the next batch citric acid fermentation. This process could eliminate wastewater discharge and reduce water resource consumption. Propionic acid was found in the ADE and its concentration continually increased in recycling. Effect of propionic acid on citric acid fermentation was investigated, and results indicated that influence of propionic acid on citric acid fermentation was contributed to the undissociated form. Citric acid fermentation was inhibited when the concentration of propionic acid was above 2, 4, and 6 mM in initial pH 4.0, 4.5 and, 5.0, respectively. However, low concentration of propionic acid could promote isomaltase activity which converted more isomaltose to available sugar, thereby increasing citric acid production. High concentration of propionic acid could influence the vitality of cell and prolong the lag phase, causing large amount of glucose still remaining in medium at the end of fermentation and decreasing citric acid production.

Proposal of law about the recovery and valorization of the gas coming from the anaerobic fermentation of organic wastes, renewable energy with a high potentiality

International Nuclear Information System (INIS)

2005-12-01

The goal of this proposal of law is the systematic and mandatory capture and valorization of the methane coming from the anaerobic fermentation of municipal and agricultural wastes, and more generally coming from any activity generating gases with at least 25% of methane. (J.S.)

Anaerobic fermentation of agricultural residue: potential for improvement and implementation. Final report, Volume II

Energy Technology Data Exchange (ETDEWEB)

Jewell, W. J.; Dell' orto, S.; Fanfoni, K. J.; Hayes, T. D.; Leuschner, A. P.; Sherman, D. F.

1980-04-01

Earlier studies have shown that although large quantities of agricultural residues are generated on small farms, it was difficult to economically justify use of conventional anaerobic digestion technology, such as used for sewage sludge digestion. A simple, unmixed, earthen-supported structure appeared to be capable of producing significant quantities of biogas at a cost that would make it competitive with many existing fuels. The goal of this study was to define and demonstrate a methane fermentation technology that could be practical and economically feasible on small farms. This study provides the first long term, large scale (reactor volumes of 34 m/sup 3/) parallel testing of the major theory, design, construction, and operation of a low cost approach to animal manure fermentation as compared to the more costly and complex designs. The main objectives were to define the lower limits for successful fermentor operation in terms of mixing, insulation, temperature, feed rate, and management requirements in a cold climate with both pilot scale and full scale fermentors. Over a period of four years, innovative fermentation processes for animal manures were developed from theoretical concept to successful full scale demonstration. Reactors were sized for 50 to 65 dairy animals, or for the one-family dairy size. The results show that a small farm biogas generation system that should be widely applicable and economically feasible was operated successfully for nearly two years. Although this low cost system out-performed the completely mixed unit throughout the study, perhaps the greatest advantage of this approach is its ease of modification, operation, and maintenance.

Methane fermentation process as anaerobic digestion of biomass ...

African Journals Online (AJOL)

Anaerobic decomposition of organic compounds is conducted in close cooperation of specialized bacteria of different types, including mostly hydrolyzing, digestive, acetogenic, homoacetogenic, sulfate-reducing (VI) and methanogenic bacteria. A great interest in the anaerobic digestion process results mainly from its ...

Real-Time Monitoring of Chemical Changes in Three Kinds of Fermented Milk Products during Fermentation Using Quantitative Difference Nuclear Magnetic Resonance Spectroscopy.

Science.gov (United States)

Lu, Yi; Ishikawa, Hiroto; Kwon, Yeondae; Hu, Fangyu; Miyakawa, Takuya; Tanokura, Masaru

2018-02-14

Fermented milk products are rising in popularity throughout the world as a result of their health benefits, including improving digestion, normalizing the function of the immune system, and aiding in weight management. This study applies an in situ quantitative nuclear magnetic resonance method to monitor chemical changes in three kinds of fermented milk products, Bulgarian yogurt, Caspian Sea yogurt, and kefir, during fermentation. As a result, the concentration changes in nine organic compounds, α/β-lactose, α/β-galactose, lactic acid, citrate, ethanol, lecithin, and creatine, were monitored in real time. This revealed three distinct metabolic processes in the three fermented milk products. Moreover, pH changes were also determined by variations in the chemical shift of citric acid during the fermentation processes. These results can be applied to estimate microbial metabolism in various flora and help guide the fermentation and storage of various fermented milk products to improve their quality, which may directly influence human health.

Hydrogen production using Rhodopseudomonas palustris WP 3-5 with hydrogen fermentation reactor effluent

International Nuclear Information System (INIS)

Chi-Mei Lee; Kuo-Tsang Hung

2006-01-01

The possibility of utilizing the dark hydrogen fermentation stage effluents for photo hydrogen production using purple non-sulfur bacteria should be elucidated. In the previous experiments, Rhodopseudomonas palustris WP3-5 was proven to efficiently produce hydrogen from the effluent of hydrogen fermentation reactors. The highest hydrogen production rate was obtained at a HRT value of 48 h when feeding a 5 fold effluent dilution from anaerobic hydrogen fermentation. Besides, hydrogen production occurred only when the NH 4 + concentration was below 17 mg-NH 4 + /l. Therefore, for successful fermentation effluent utilization, the most important things were to decrease the optimal HRT, increase the optimal substrate concentration and increase the tolerable ammonia concentration. In this study, a lab-scale serial photo-bioreactor was constructed. The reactor overall hydrogen production efficiency with synthetic wastewater exhibiting an organic acid profile identical to that of anaerobic hydrogen fermentation reactor effluent and with effluent from two anaerobic hydrogen fermentation reactors was evaluated. (authors)

Caldicellulosiruptor obsidiansis sp. nov., an anaerobic, extremely thermophilic, cellulolytic bacterium isolated from Obsidian Pool, Yellowstone National Park.

Science.gov (United States)

Hamilton-Brehm, Scott D; Mosher, Jennifer J; Vishnivetskaya, Tatiana; Podar, Mircea; Carroll, Sue; Allman, Steve; Phelps, Tommy J; Keller, Martin; Elkins, James G

2010-02-01

A novel, obligately anaerobic, extremely thermophilic, cellulolytic bacterium, designated OB47(T), was isolated from Obsidian Pool, Yellowstone National Park, WY. The isolate was a nonmotile, non-spore-forming, Gram-positive rod approximately 2 microm long by 0.2 microm wide and grew at temperatures between 55 and 85 degrees C, with the optimum at 78 degrees C. The pH range for growth was 6.0 to 8.0, with values of near 7.0 being optimal. Growth on cellobiose produced the fastest specific growth rate at 0.75 h(-1). The organism also displayed fermentative growth on glucose, maltose, arabinose, fructose, starch, lactose, mannose, sucrose, galactose, xylose, arabinogalactan, Avicel, xylan, filter paper, processed cardboard, pectin, dilute acid-pretreated switchgrass, and Populus. OB47(T) was unable to grow on mannitol, fucose, lignin, Gelrite, acetate, glycerol, ribose, sorbitol, carboxymethylcellulose, and casein. Yeast extract stimulated growth, and thiosulfate, sulfate, nitrate, and sulfur were not reduced. Fermentation end products were mainly acetate, H2, and CO2, although lactate and ethanol were produced in 5-liter batch fermentations. The G+C content of the DNA was 35 mol%, and sequence analysis of the small subunit rRNA gene placed OB47(T) within the genus Caldicellulosiruptor. Based on its phylogenetic and phenotypic properties, the isolate is proposed to be designated Caldicellulosiruptor obsidiansis sp. nov. and OB47 is the type strain (ATCC BAA-2073).

Caldicellulosiruptor obsidiansis sp. nov., an Anaerobic, Extremely Thermophilic, Cellulolytic Bacterium Isolated from Obsidian Pool, Yellowstone National Park▿

Science.gov (United States)

Hamilton-Brehm, Scott D.; Mosher, Jennifer J.; Vishnivetskaya, Tatiana; Podar, Mircea; Carroll, Sue; Allman, Steve; Phelps, Tommy J.; Keller, Martin; Elkins, James G.

2010-01-01

A novel, obligately anaerobic, extremely thermophilic, cellulolytic bacterium, designated OB47T, was isolated from Obsidian Pool, Yellowstone National Park, WY. The isolate was a nonmotile, non-spore-forming, Gram-positive rod approximately 2 μm long by 0.2 μm wide and grew at temperatures between 55 and 85°C, with the optimum at 78°C. The pH range for growth was 6.0 to 8.0, with values of near 7.0 being optimal. Growth on cellobiose produced the fastest specific growth rate at 0.75 h−1. The organism also displayed fermentative growth on glucose, maltose, arabinose, fructose, starch, lactose, mannose, sucrose, galactose, xylose, arabinogalactan, Avicel, xylan, filter paper, processed cardboard, pectin, dilute acid-pretreated switchgrass, and Populus. OB47T was unable to grow on mannitol, fucose, lignin, Gelrite, acetate, glycerol, ribose, sorbitol, carboxymethylcellulose, and casein. Yeast extract stimulated growth, and thiosulfate, sulfate, nitrate, and sulfur were not reduced. Fermentation end products were mainly acetate, H2, and CO2, although lactate and ethanol were produced in 5-liter batch fermentations. The G+C content of the DNA was 35 mol%, and sequence analysis of the small subunit rRNA gene placed OB47T within the genus Caldicellulosiruptor. Based on its phylogenetic and phenotypic properties, the isolate is proposed to be designated Caldicellulosiruptor obsidiansis sp. nov. and OB47 is the type strain (ATCC BAA-2073). PMID:20023107

Effect of acetic acid on citric acid fermentation in an integrated citric acid-methane fermentation process.

Science.gov (United States)

Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

2014-09-01

An integrated citric acid-methane fermentation process was proposed to solve the problem of extraction wastewater in citric acid fermentation process. Extraction wastewater was treated by anaerobic digestion and then recycled for the next batch of citric acid fermentation to eliminate wastewater discharge and reduce water resource consumption. Acetic acid as an intermediate product of methane fermentation was present in anaerobic digestion effluent. In this study, the effect of acetic acid on citric acid fermentation was investigated and results showed that lower concentration of acetic acid could promote Aspergillus niger growth and citric acid production. 5-Cyano-2,3-ditolyl tetrazolium chloride (CTC) staining was used to quantify the activity of A. niger cells, and the results suggested that when acetic acid concentration was above 8 mM at initial pH 4.5, the morphology of A. niger became uneven and the part of the cells' activity was significantly reduced, thereby resulting in deceasing of citric acid production. Effects of acetic acid on citric acid fermentation, as influenced by initial pH and cell number in inocula, were also examined. The result indicated that inhibition by acetic acid increased as initial pH declined and was rarely influenced by cell number in inocula.

Combined bioaugmentation with anaerobic ruminal fungi and fermentative bacteria to enhance biogas production from wheat straw and mushroom spent straw.

Science.gov (United States)

Ferraro, Alberto; Dottorini, Giulia; Massini, Giulia; Mazzurco Miritana, Valentina; Signorini, Antonella; Lembo, Giuseppe; Fabbricino, Massimiliano

2018-07-01

Bioaugmentation with anaerobic ruminal fungi and a pool of hydrogen-producing fermenting bacteria was tested on wheat straw (WS) and mushroom spent straw (MSS) with the aim of improving anaerobic digestion performance. Batch tests were set up to simulate a Bioaugmentation Anaerobic Digestion (BAD) treatment comparing single- (I-BAD) and two-stage (II-BAD) process configurations, at two reactor scales, 120 and 1200 ml (×10). In both cases, higher CH 4 cumulative production was obtained in the II-BAD configuration on WS (65.1 ± 8.9 Nml and 922 ± 73.8 Nml respectively). The II-BADx10 tests allowed increasing CH 4 production (≃290% and ≃330% on WS and MSS, respectively) when compared to the unaugmented condition. Final results highlighted the achievable advantages of the two stage configuration in terms of CH 4 production enhancement. Microbial community investigations confirmed the efficiency of the bioaugmentation treatment and revealed that such a result was mainly related to the Methanosarcinales increase, mostly composed by Methanosaeta. Copyright © 2018 Elsevier Ltd. All rights reserved.

Schematic Method for Effective Identification of Anaerobes from ...

African Journals Online (AJOL)

They were inoculated into two compounded media; Neomycin Blood Agar (NBA) and Neomycin Plasma Agar (NPA) incubated anaerobically at 37oC for (24-48) hours. Isolated anaerobes were gram-stained and tested using discs impregnated with antibiotics, bile salts and dyes, carbohydrate fermentation and other ...

Moroccan rock phosphate solubilization during a thermo-anaerobic ...

African Journals Online (AJOL)

In order to investigate the presence of thermo-tolerant rock phosphate (RP) solubilizing anaerobic microbes during the fermentation process, we used grassland as sole organic substrate to evaluate the RP solubilization process under anaerobic thermophilic conditions. The result shows a significant decrease of pH from ...

Effect of ferrous chloride on biogas production and enzymatic activities during anaerobic fermentation of cow dung and Phragmites straw.

Science.gov (United States)

Zhang, Huayong; Tian, Yonglan; Wang, Lijun; Mi, Xueyue; Chai, Yang

2016-06-01

The effect of ferrous (added as FeCl2) on the anaerobic co-digestion of Phragmites straw and cow dung was studied by investigating the biogas properties, pH values, organic matter degradation (COD) and enzyme activities (cellulase, protease and dehydrogenase) at different stages of mesophilic fermentation. The results showed that Fe(2+) addition increased the cumulative biogas yields by 18.1 % by extending the peak period with high daily biogas yields. Meanwhile, the methane (CH4) contents in the Fe(2+) added groups were generally higher than the control group before the 15th day. The pH values were not significantly impacted by Fe(2+) concentrations during the fermentation process. The COD concentrations, cellulase, protease and dehydrogenase activities varied with the added Fe(2+) concentrations and the stages of the fermentation process. At the beginning stage of fermentation (4th day), Fe(2+) addition increased the biogas production by improving the cellulase and dehydrogenase activities which caused a decline in COD. At the peak stage of fermentation (8th day), Fe(2+) addition enhanced the cellulase and protease activities, and resulted in lower COD contents than the control group. When the biogas yields decreased again (13th day), the COD contents varied similar with the protease and dehydrogenase activities, whilst cellulase activities were not sensitive to Fe(2+) concentrations. At the end of fermentation (26th day), Fe(2+) addition decreased the cellulase activities, led to lower COD contents and finally resulted the lower biogas yields than the control group. Taking the whole fermentation process into account, the promoting effect of Fe(2+) addition on biogas yields was mainly attributed to the extension of the gas production peak stage and the improvement of cellulase activities.

Role of anaerobic fungi in wheat straw degradation and effects of plant feed additives on rumen fermentation parameters in vitro.

Science.gov (United States)

Dagar, S S; Singh, N; Goel, N; Kumar, S; Puniya, A K

2015-01-01

In the present study, rumen microbial groups, i.e. total rumen microbes (TRM), total anaerobic fungi (TAF), avicel enriched bacteria (AEB) and neutral detergent fibre enriched bacteria (NEB) were evaluated for wheat straw (WS) degradability and different fermentation parameters in vitro. Highest WS degradation was shown for TRM, followed by TAF, NEB and least by AEB. Similar patterns were observed with total gas production and short chain fatty acid profiles. Overall, TAF emerged as the most potent individual microbial group. In order to enhance the fibrolytic and rumen fermentation potential of TAF, we evaluated 18 plant feed additives in vitro. Among these, six plant additives namely Albizia lebbeck, Alstonia scholaris, Bacopa monnieri, Lawsonia inermis, Psidium guajava and Terminalia arjuna considerably improved WS degradation by TAF. Further evaluation showed A. lebbeck as best feed additive. The study revealed that TAF plays a significant role in WS degradation and their fibrolytic activities can be improved by inclusion of A. lebbeck in fermentation medium. Further studies are warranted to elucidate its active constituents, effect on fungal population and in vivo potential in animal system.

A Mutation in PGM2 Causing Inefficient Galactose Metabolism in the Probiotic Yeast Saccharomyces boulardii.

Science.gov (United States)

Liu, Jing-Jing; Zhang, Guo-Chang; Kong, In Iok; Yun, Eun Ju; Zheng, Jia-Qi; Kweon, Dae-Hyuk; Jin, Yong-Su

2018-05-15

The probiotic yeast Saccharomyces boulardii has been extensively studied for the prevention and treatment of diarrheal diseases, and it is now commercially available in some countries. S. boulardii displays notable phenotypic characteristics, such as a high optimal growth temperature, high tolerance against acidic conditions, and the inability to form ascospores, which differentiate S. boulardii from Saccharomyces cerevisiae The majority of prior studies stated that S. boulardii exhibits sluggish or halted galactose utilization. Nonetheless, the molecular mechanisms underlying inefficient galactose uptake have yet to be elucidated. When the galactose utilization of a widely used S. boulardii strain, ATCC MYA-796, was examined under various culture conditions, the S. boulardii strain could consume galactose, but at a much lower rate than that of S. cerevisiae While all GAL genes were present in the S. boulardii genome, according to analysis of genomic sequencing data in a previous study, a point mutation (G1278A) in PGM2 , which codes for phosphoglucomutase, was identified in the genome of the S. boulardii strain. As the point mutation resulted in the truncation of the Pgm2 protein, which is known to play a pivotal role in galactose utilization, we hypothesized that the truncated Pgm2 might be associated with inefficient galactose metabolism. Indeed, complementation of S. cerevisiae PGM2 in S. boulardii restored galactose utilization. After reverting the point mutation to a full-length PGM2 in S. boulardii by Cas9-based genome editing, the growth rates of wild-type (with a truncated PGM2 gene) and mutant (with a full-length PGM2 ) strains with glucose or galactose as the carbon source were examined. As expected, the mutant (with a full-length PGM2 ) was able to ferment galactose faster than the wild-type strain. Interestingly, the mutant showed a lower growth rate than that of the wild-type strain on glucose at 37°C. Also, the wild-type strain was enriched in the

[Enhanced nitrogen and phosphorus removal of wastewater by using sludge anaerobic fermentation liquid as carbon source in a pilot-scale system].

Science.gov (United States)

Luo, Zhe; Zhou, Guang-Jie; Liu, Hong-Bo; Nie, Xin-Yu; Chen, Yu; Zhai, Li-Qin; Liu, He

2015-03-01

In order to explore the possibility of enhanced nitrogen and phosphorus removal in wastewater using sludge anaerobic fermentation liquid as external carbon source, the present study proposed an A2/O reactor system with a total effective volume of 4 660 L and real municipal wastewater for treatment. The results showed that under the conditions of the influent COD at 243.7 mg x L(-1), NH4(+) -N at 30. 9 mg x L(-1), TN at 42.9 mg'L- , TP at 2.8 mg x L(-1), the backflow ratio of nitrification liquid at 200% and recycle ratio of sludge at 100%, the addition of acetic acid into anoxic tank could enhance the removal efficiency of nitrogen and phosphorus, and the optimal influent quantity and SCOD incremental of carbon were 7 500 L x d(-1) and 50 mg L(-1), respectively. When the sludge fermentation liquid was used as external carbon source and the average effluent COD, NH4(+) -N, TN, TP removal efficiency were 81.60%, 88.91%, 64.86% and 87.61%, the effluent concentrations were 42.18, 2.77, 11.92 and 0.19 mg x L(-1), respectively, which met China's first Class (A) criteria specified in the Discharge Standard Urban Sewage Treatment Plant Pollutant (GB 18918-2002). The results of the present study demonstrated that the addition of sludge anaerobic fermented liquid as external carbon source was a feasible way to enhance the removal of nitrogen and phosphorous in municipal wastewater, providing a new feasible strategy for the reuse and recycle of sewage sludge in China.

Methanic fermentation of manure

Energy Technology Data Exchange (ETDEWEB)

Donadeo, M

1954-06-01

A comparison between the chemical composition of manure ripened in conventional ditches and that of manure anaerobically fermented in tanks led to the conclusion that the latter was not satisfactory; the resulting manure was less valuable.

Lactic acid production from potato peel waste by anaerobic sequencing batch fermentation using undefined mixed culture.

Science.gov (United States)

Liang, Shaobo; McDonald, Armando G; Coats, Erik R

2015-11-01

Lactic acid (LA) is a necessary industrial feedstock for producing the bioplastic, polylactic acid (PLA), which is currently produced by pure culture fermentation of food carbohydrates. This work presents an alternative to produce LA from potato peel waste (PPW) by anaerobic fermentation in a sequencing batch reactor (SBR) inoculated with undefined mixed culture from a municipal wastewater treatment plant. A statistical design of experiments approach was employed using set of 0.8L SBRs using gelatinized PPW at a solids content range from 30 to 50 g L(-1), solids retention time of 2-4 days for yield and productivity optimization. The maximum LA production yield of 0.25 g g(-1) PPW and highest productivity of 125 mg g(-1) d(-1) were achieved. A scale-up SBR trial using neat gelatinized PPW (at 80 g L(-1) solids content) at the 3 L scale was employed and the highest LA yield of 0.14 g g(-1) PPW and a productivity of 138 mg g(-1) d(-1) were achieved with a 1 d SRT. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biochemical Hypermedia: Galactose Metabolism.

Directory of Open Access Journals (Sweden)

J.K. Sugai

2013-05-01

Full Text Available Introduction: Animations of biochemical processes and virtual laboratory environments lead to true molecular simulations. The use of interactive software’s in education can improve cognitive capacity, better learning and, mainly, it makes information acquisition easier. Material and Methods: This work presents the development of a biochemical hypermedia to understanding of the galactose metabolism. It was developed with the help of concept maps, ISIS Draw, ADOBE Photoshop and FLASH MX Program. Results and Discussion: A step by step animation process shows the enzymatic reactions of galactose conversion to glucose-1-phosphate (to glycogen synthesis, glucose-6-phosphate (glycolysis intermediary, UDP-galactose (substrate to mucopolysaccharides synthesis and collagen’s glycosylation. There are navigation guide that allow scrolling the mouse over the names of the components of enzymatic reactions of via the metabolism of galactose. Thus, explanatory text box, chemical structures and animation of the actions of enzymes appear to navigator. Upon completion of the module, the user’s response to the proposed exercise can be checked immediately through text box with interactive content of the answer. Conclusion: This hypermedia was presented for undergraduate students (UFSC who revealed that it was extremely effective in promoting the understanding of the theme.

Expression of the E.coli pntA and pntB genes encoding nicotinamide nucleotide transhydrogenase in Saccharomyces cerevisiae and its effect on product formation during anaerobic glucose fermentation

DEFF Research Database (Denmark)

Anderlund, M.; Nissen, Torben Lauesgaard; Nielsen, Jens Bredal

1999-01-01

was present. Unlike the situation in E. coli, however, most of the transhydrogenase activity was not present in the yeast plasma membrane; rather, the enzyme appeared to remain localized in the membrane of the endoplasmic reticulum. During anaerobic glucose fermentation we observed an increase...

Continuous Ethanol Fermentation of Pretreated Lignocellulosic Biomasses, Waste Biomasses, Molasses and Syrup Using the Anaerobic, Thermophilic Bacterium Thermoanaerobacter italicus Pentocrobe 411

Science.gov (United States)

Andersen, Rasmus Lund; Jensen, Karen Møller; Mikkelsen, Marie Just

2015-01-01

Lignocellosic ethanol production is now at a stage where commercial or semi-commercial plants are coming online and, provided cost effective production can be achieved, lignocellulosic ethanol will become an important part of the world bio economy. However, challenges are still to be overcome throughout the process and particularly for the fermentation of the complex sugar mixtures resulting from the hydrolysis of hemicellulose. Here we describe the continuous fermentation of glucose, xylose and arabinose from non-detoxified pretreated wheat straw, birch, corn cob, sugar cane bagasse, cardboard, mixed bio waste, oil palm empty fruit bunch and frond, sugar cane syrup and sugar cane molasses using the anaerobic, thermophilic bacterium Thermoanaerobacter Pentocrobe 411. All fermentations resulted in close to maximum theoretical ethanol yields of 0.47–0.49 g/g (based on glucose, xylose, and arabinose), volumetric ethanol productivities of 1.2–2.7 g/L/h and a total sugar conversion of 90–99% including glucose, xylose and arabinose. The results solidify the potential of Thermoanaerobacter strains as candidates for lignocellulose bioconversion. PMID:26295944

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

Nutritive value of palm oil sludge fermented with Aspergillus niger after therma1 drying process

Directory of Open Access Journals (Sweden)

T Purwadaria

1999-12-01

Full Text Available Solid substrate fermentation by Aspergillus niger has been carried out to improve the nutritive value of palm oil sludge (POS. POS was fermented aerobically for four days in a fermentor chambers (28°C, RH 80%, with 60% moisture content Some of the product was further incubated anaerobically for 2 days at 28°C. Both products from aerobic and anaerobic fermentation processes were dried by various methods, i.e. sunlight, oven at 60°C, oven with blower at 40°C, at the moisture content less than 11%. Results of the drying methods were also compared with the fresh fermented product. Statistic analysis using factorial design (2 x 4 showed that there was no interaction between kind of fermentation processes (aerobic and anaerobic and drying methods (fresh, sunlight, oven 60°C, and blower 40°C for almost all parameters except total a-amino acid content Significant results (p<0.05 were obtained on the drying methods for parameters of crude protein, true protein, in vitro dry matter and protein digestibilities, and mannanase and cellulase activities. There were no significant results between treatments in the crude fiber analysis and soluble nitrogen content Significant results also did not occur between treatment of aerob and anaerob fermentation processes for almost all parameters except for dry matter digestibilities. Results from true protein and in vitro digestibilities show that the fresh fermented product has the best nutritive value, while product dried by sunlight was best among other drying processes. Results from in vivo of protein and energy digestibilities show that there were better metabolizable energy and protein for product with aerobic process and dried with oven and blower treatments, while sunlight drying was best for product processed in anaerobic condition. Although fresh fermented product gave better result from in vitro digestibilities and enzyme activity analyses, for some reasons (easy handling and preservation sunlight

Review of enhanced processes for anaerobic digestion treatment of sewage sludge

Science.gov (United States)

Liu, Xinyuan; Han, Zeyu; Yang, Jie; Ye, Tianyi; Yang, Fang; Wu, Nan; Bao, Zhenbo

2018-02-01

Great amount of sewage sludge had been produced each year, which led to serious environmental pollution. Many new technologies had been developed recently, but they were hard to be applied in large scales. As one of the traditional technologies, anaerobic fermentation process was capable of obtaining bioenergy by biogas production under the functions of microbes. However, the anaerobic process is facing new challenges due to the low fermentation efficiency caused by the characteristics of sewage sludge itself. In order to improve the energy yield, the enhancement technologies including sewage sludge pretreatment process, co-digestion process, high-solid digestion process and two-stage fermentation process were widely studied in the literatures, which were introduced in this article.

Galactose Epimerase Deficiency: Expanding the Phenotype

NARCIS (Netherlands)

Dias Costa, Filipa; Ferdinandusse, Sacha; Pinto, Carla; Dias, Andrea; Keldermans, Liesbeth; Quelhas, Dulce; Matthijs, Gert; Mooijer, Petra A.; Diogo, Luísa; Jaeken, Jaak; Garcia, Paula

2017-01-01

Galactose epimerase deficiency is an inborn error of metabolism due to uridine diphosphate-galactose-4'-epimerase (GALE) deficiency. We report the clinical presentation, genetic and biochemical studies in two siblings with generalized GALE deficiency.Patient 1: The first child was born with a

Copper stressed anaerobic fermentation: biogas properties, process stability, biodegradation and enzyme responses.

Science.gov (United States)

Hao, He; Tian, Yonglan; Zhang, Huayong; Chai, Yang

2017-12-01

The effect of copper (added as CuCl 2 ) on the anaerobic co-digestion of Phragmites straw and cow dung was studied in pilot experiments by investigating the biogas properties, process stability, substrate degradation and enzyme activities at different stages of mesophilic fermentation. The results showed that 30 and 100 mg/L Cu 2+ addition increased the cumulative biogas yields by up to 43.62 and 20.77% respectively, and brought forward the daily biogas yield peak, while 500 mg/L Cu 2+ addition inhibited biogas production. Meanwhile, the CH 4 content in the 30 and 100 mg/L Cu 2+ -added groups was higher than that in the control group. Higher pH values (close to pH 7) and lower oxidation-reduction potential (ORP) values in the Cu 2+ -added groups after the 8th day indicated better process stability compared to the control group. In the presence of Cu 2+ , the degradation of volatile fatty acids (VFAs) and other organic molecules (represented by chemical oxygen demand, COD) generated from hydrolysis was enhanced, and the ammonia nitrogen (NH 4 + -N) concentrations were more stable than in the control group. The contents of lignin and hemicellulose in the substrate declined in the Cu 2+ -added groups while the cellulose contents did not. Neither the cellulase nor the coenzyme F 420 activities could determine the biogas producing efficiency. Taking the whole fermentation process into account, the promoting effect of Cu 2+ addition on biogas yields was mainly attributable to better process stability, the enhanced degradation of lignin and hemicellulose, the transformation of intermediates into VFA, and the generation of CH 4 from VFA.

Biogas properties and enzymatic analysis during anaerobic fermentation of Phragmites australis straw and cow dung: influence of nickel chloride supplement.

Science.gov (United States)

Tian, Yonglan; Zhang, Huayong; Chai, Yang; Wang, Lijun; Mi, Xueyue; Zhang, Luyi; Ware, Maxwell Adam

2017-02-01

The importance of nickel (added as NiCl 2 ) on mesophilic anaerobic fermentation of Phragmites australis straw and cow dung was demonstrated by investigating the biogas properties, pH values, organic matter degradation [chemical oxygen demand (COD)] and enzyme activities (cellulase, protease and dehydrogenase) during the fermentation process. The results showed that Ni 2+ addition increased the cumulative biogas yields by >18 % by improving the efficiency of first peak stage and bringing forward the second peak stage. The pH values were not significantly influenced by Ni 2+ addition (p > 0.05). Biogas yields were associated with variations in COD concentrations rather than momentary concentrations. At the start-up stage of fermentation (4th day), the biogas yields increased gradually together with the increase of dehydrogenase activities at elevated Ni 2+ concentrations when cellulase and protease activities were similar in all test groups. It is suggested that Ni 2+ addition was mainly dependent on the methanogenic stage. After the start-up stage, the impact of Ni 2+ addition on biogas production was mainly dependent on its effect on cellulase activities, rather than protease or dehydrogenase activities.

Anaerobic biotechnological approaches for production of liquid energy carriers from biomass

DEFF Research Database (Denmark)

Karakashev, Dimitar Borisov; Thomsen, Anne Belinda; Angelidaki, Irini

2007-01-01

In recent years, increasing attention has been paid to the use of renewable biomass for energy production. Anaerobic biotechnological approaches for production of liquid energy carriers (ethanol and a mixture of acetone, butanol and ethanol) from biomass can be employed to decrease environmental...... pollution and reduce dependency on fossil fuels. There are two major biological processes that can convert biomass to liquid energy carriers via anaerobic biological breakdown of organic matter: ethanol fermentation and mixed acetone, butanol, ethanol (ABE) fermentation. The specific product formation...

Electron donation characteristics and interplays of major volatile fatty acids from anaerobically fermented organic matters in bioelectrochemical systems.

Science.gov (United States)

Zhang, Zhiqiang; Li, Jiamiao; Hao, Xiaoxuan; Gu, Zaoli; Xia, Siqing

2018-02-23

Anaerobic fermentation liquid of waste organic matters (WOMs) is rich in volatile fatty acids (VFAs), which can be treated with bioelectrochemical systems for both electrical energy recovery and organics removal. In this work, four major VFAs in the fermented WOMs supernatant were selected to examine their electron donation characteristics for power output and their complicated interplays in microbial fuel cells (MFCs). Results indicated a priority sequence of acetate, propionate, n-butyrate and i-valerate when served as the sole electron donor for electricity generation. The MFC solely fed with acetate showed the highest coulombic efficiency and power density, and the longest period for electricity production. When two of the VFAs were added with equal proportion, both acids contributed positively to electricity generation, while the selective or competitive use of substrates by diverse microorganisms behaved as an antagonism effect to prolong the degradation time of each VFA. When acetate and propionate, the preferable substrates for electricity generation, were mixed in various proportions, their large concentration difference led to improved electrical performance but decreased organic removal rate.

Metabolism in anoxic permeable sediments is dominated by eukaryotic dark fermentation

Science.gov (United States)

Bourke, Michael F.; Marriott, Philip J.; Glud, Ronnie N.; Hasler-Sheetal, Harald; Kamalanathan, Manoj; Beardall, John; Greening, Chris; Cook, Perran L. M.

2017-01-01

Permeable sediments are common across continental shelves and are critical contributors to marine biogeochemical cycling. Organic matter in permeable sediments is dominated by microalgae, which as eukaryotes have different anaerobic metabolic pathways to bacteria and archaea. Here we present analyses of flow-through reactor experiments showing that dissolved inorganic carbon is produced predominantly as a result of anaerobic eukaryotic metabolic activity. In our experiments, anaerobic production of dissolved inorganic carbon was consistently accompanied by large dissolved H2 production rates, suggesting the presence of fermentation. The production of both dissolved inorganic carbon and H2 persisted following administration of broad spectrum bactericidal antibiotics, but ceased following treatment with metronidazole. Metronidazole inhibits the ferredoxin/hydrogenase pathway of fermentative eukaryotic H2 production, suggesting that pathway as the source of H2 and dissolved inorganic carbon production. Metabolomic analysis showed large increases in lipid production at the onset of anoxia, consistent with documented pathways of anoxic dark fermentation in microalgae. Cell counts revealed a predominance of microalgae in the sediments. H2 production was observed in dark anoxic cultures of diatoms (Fragilariopsis sp.) and a chlorophyte (Pyramimonas) isolated from the study site, substantiating the hypothesis that microalgae undertake fermentation. We conclude that microalgal dark fermentation could be an important energy-conserving pathway in permeable sediments.

Aerobic Stability and Effects of Yeasts during Deterioration of Non-fermented and Fermented Total Mixed Ration with Different Moisture Levels

OpenAIRE

W. Hao; H. L. Wang; T. T. Ning; F. Y. Yang; C. C. Xu

2015-01-01

The present experiment evaluated the influence of moisture level and anaerobic fermentation on aerobic stability of total mixed ration (TMR). The dynamic changes in chemical composition and microbial population that occur after air exposure were examined, and the species of yeast associated with the deterioration process were also identified in both non-fermented and fermented TMR to deepen the understanding of aerobic deterioration. The moisture levels of TMR in this experiment were adjusted...

Improving wood hydrolyzate fermentation by using schizosaccharomycetes

Energy Technology Data Exchange (ETDEWEB)

Kalyuzhnyi, M Ya; Ustinova, V I; Petrushko, G I

1967-01-01

The development of Schizosaccharomycetes (I) in wood hydrolyzates is not observed when fermentation is carried out by the convetional batch process, evidently because of the highly inhibitory action of the medium. More recently, with the introduction of continuous fermentation of wood and other hydrolyzates, the occurrence of I has been frequently reported, and in some hydrolysis plants, I became predominant, eliminating the budding yeast strains. The phenomenon can be attributed to higher temperatures employed in continuous fermentation, and to a more favorable medium, as the hydrolyzate is diluted with spent fermentation liquor (the flow of fresh medium constitutes about 20% of the fermentation-vat volume). The I cells, when grown under favorable conditions, have a high fermenting power, adapt easily to the fermentation of galactose, and give higher yields of ethanol than the budding yeast. As observed at plants using I, however, the cells are sensitive to variations in the fermentation process, and are inactivated upon storage. This is usually attributed to their inability to store polysaccharides, and especially glycogen. An experimental study undertaken to determine conditions under which reserve polysaccharides accumulate in I cells showed that the important factor is the quality of the medium in which the cells are grown and the conditions of storage. In media enriched with spent fermentaion liquor or with cell autolyzate and purified from toxic components, considerable amounts of glycogen accumulate in the cells.

Simultaneous co-fermentation of mixed sugars: a promising strategy for producing cellulosic ethanol.

Science.gov (United States)

Kim, Soo Rin; Ha, Suk-Jin; Wei, Na; Oh, Eun Joong; Jin, Yong-Su

2012-05-01

The lack of microbial strains capable of fermenting all sugars prevalent in plant cell wall hydrolyzates to ethanol is a major challenge. Although naturally existing or engineered microorganisms can ferment mixed sugars (glucose, xylose and galactose) in these hydrolyzates sequentially, the preferential utilization of glucose to non-glucose sugars often results in lower overall yield and productivity of ethanol. Therefore, numerous metabolic engineering approaches have been attempted to construct optimal microorganisms capable of co-fermenting mixed sugars simultaneously. Here, we present recent findings and breakthroughs in engineering yeast for improved ethanol production from mixed sugars. In particular, this review discusses new sugar transporters, various strategies for simultaneous co-fermentation of mixed sugars, and potential applications of co-fermentation for producing fuels and chemicals. Copyright © 2012 Elsevier Ltd. All rights reserved.

Kinetic isotope effects in reaction of ferment oxidation of tritium-labelled D-galactosamine

International Nuclear Information System (INIS)

Akulov, G.P.; Korsakova, N.A.

1992-01-01

Primary, secondary and intramolecular kinetic isotopic effects in reaction of ferment oxidation of D-galactosamine labelled by tritium in position 6, were measured. When comparing values of the effects with previously obtained results for similar reaction D-[6- 3 H]galactose, it was ascertained that the presence of aminogroup in galactopyranosyl mainly affects kinetics of substrate-ferment complex formation stage. The possibility to use kinetic isotope effects for increase in molar activity of D-galactosamine, labelled by tritium in position 6, is shown

Ultrasonic Monitoring of the Progress of Lactic Acid Fermentation

Science.gov (United States)

Masuzawa, Nobuyoshi; Kimura, Akihiro; Ohdaira, Etsuzo

2003-05-01

Promotion of lactic acid fermentation by ultrasonic irradiation has been attempted. It is possible to determine the progress of fermentation and production of a curd, i.e., yoghurt and or kefir, by measuring acidity using a pH meter. However, this method is inconvenient and indirect for the evaluation of the progress of lactic acid fermentation under anaerobic condition. In this study, an ultrasonic monitoring method for evaluating the progress of lactic acid fermentation was examined.

Simulation of the anaerobic digestion process

Energy Technology Data Exchange (ETDEWEB)

Maia, C A.M.

1981-01-01

The dynamic model of anaerobic fermentation includes an inhibition function to relate volatile acid concentration to a specific growth rate for the methane bacteria and also includes the interactions between the liquid, gaseous, and biology phases of the digester.

NADPH-dependent D-aldose reductases and xylose fermentation in Fusarium oxysporum

DEFF Research Database (Denmark)

Panagiotou, Gianni; Christakopoulos, P.

2004-01-01

for NADPH over NADH. In this study, the influence of aeration and the response to the addition of electron acceptors on xylose fermentation by F. oxysporum were also studied. The batch cultivation of F. oxysporum on xylose was performed under aerobic, anaerobic and oxygen-limited conditions in stirred tank...... conditions (0.3 vvm). When the artificial electron acceptor acetoin was added to an anaerobic batch fermentation of xylose by F. oxysporum, the ethanol yield increased while xylitol excretion was also decreased....

Recent development of anaerobic digestion processes for energy recovery from wastes.

Science.gov (United States)

Nishio, Naomichi; Nakashimada, Yutaka

2007-02-01

Anaerobic digestion leads to the overall gasification of organic wastewaters and wastes, and produces methane and carbon dioxide; this gasification contributes to reducing organic matter and recovering energy from organic carbons. Here, we propose three new processes and demonstrate the effectiveness of each process. By using complete anaerobic organic matter removal process (CARP), in which diluted wastewaters such as sewage and effluent from a methane fermentation digester were treated under anaerobic condition for post-treatment, the chemical oxygen demand (COD) in wastewater was decreased to less than 20 ppm. The dry ammonia-methane two-stage fermentation process (Am-Met process) is useful for the anaerobic treatment of nitrogen-rich wastes such as waste excess sludge, cow feces, chicken feces, and food waste without the dilution of the ammonia produced by water or carbon-rich wastes. The hydrogen-methane two-stage fermentation (Hy-Met process), in which the hydrogen produced in the first stage is used for a fuel cell system to generate electricity and the methane produced in the second stage is used to generate heat energy to heat the two reactors and satisfy heat requirements, is useful for the treatment of sugar-rich wastewaters, bread wastes, and biodiesel wastewaters.

Effect of ethanol on galactose tolerance in man

Energy Technology Data Exchange (ETDEWEB)

Gregg, C.T.; Rudnick, J.; McInteer, B.B.; Whaley, T.W.; Shreeve, W.W.

1978-01-01

Galactose-/sup 13/C was given to 18 subjects; /sup 13/CO/sub 2/ excretion in respiratory air was followed for 3 hours. Each subject was given galactose-/sup 13/C/sub 6/ (10 g/m/sup 2/), then retested some days later with the same amount of labeled sugar and a low level (3.5 g/m/sup 2/) of ethanol. On the basis of the /sup 13/CO/sub 2/ excretion curves in the presence and absence of ethanol, the subjects were divided into four groups (i.e., subjects considered as normal, probably normal, probable liver damage, and liver damage). Ethanol strongly inhibited galactose metabolism in normal subjects. This effect of ethanol progressively declined in the four groups until, in the last group (liver damage), ethanol had no further effect on the already severely depressed oxidation of galactose. Comparison of the galactose tolerance data with other clinical tests and with the results of a drinking history suggests that the ethanol-primed galactose tolerance test may give good discrimination between groups of people with varying degrees of liver damage short of frank cirrhosis, although alcohol-priming is not necessary to distinguish between normal and cirrhotic subjects.

[Anaerobic digestion of lignocellulosic biomass with animal digestion mechanisms].

Science.gov (United States)

Wu, Hao; Zhang, Pan-Yue; Guo, Jian-Bin; Wu, Yong-Jie

2013-02-01

Lignocellulosic material is the most abundant renewable resource in the earth. Herbivores and wood-eating insects are highly effective in the digestion of plant cellulose, while anaerobic digestion process simulating animal alimentary tract still remains inefficient. The digestion mechanisms of herbivores and wood-eating insects and the development of anaerobic digestion processes of lignocellulose were reviewed for better understanding of animal digestion mechanisms and their application in design and operation of the anaerobic digestion reactor. Highly effective digestion of lignocellulosic materials in animal digestive system results from the synergistic effect of various digestive enzymes and a series of physical and biochemical reactions. Microbial fermentation system is strongly supported by powerful pretreatment, such as rumination of ruminants, cellulase catalysis and alkali treatment in digestive tract of wood-eating insects. Oxygen concentration gradient along the digestive tract may stimulate the hydrolytic activity of some microorganisms. In addition, the excellent arrangement of solid retention time, digesta flow and end product discharge enhance the animal digestion of wood cellulose. Although anaerobic digestion processes inoculated with rumen microorganisms based rumen digestion mechanisms were developed to treat lignocellulose, the fermentation was more greatly limited by the environmental conditions in the anaerobic digestion reactors than that in rumen or hindgut. Therefore, the anaerobic digestion processes simulating animal digestion mechanisms can effectively enhance the degradation of wood cellulose and other organic solid wastes.

The Curing Agent Sodium Nitrite, Used in the Production of Fermented Sausages, Is Less Inhibiting to the Bacteriocin-Producing Meat Starter Culture Lactobacillus curvatus LTH 1174 under Anaerobic Conditions

Science.gov (United States)

Verluyten, Jurgen; Messens, Winy; De Vuyst, Luc

2003-01-01

Curvacin A is a listericidal bacteriocin produced by Lactobacillus curvatus LTH 1174, a strain isolated from fermented sausage. The response of this strain to an added curing agent (sodium nitrite) in terms of cell growth and bacteriocin production was investigated in vitro by laboratory fermentations with modified MRS broth. The strain was highly sensitive to nitrite; even a concentration of 10 ppm of curing agent inhibited its growth and both volumetric and specific bacteriocin production. A meat simulation medium containing 5 ppm of sodium nitrite was tested to investigate the influence of the gas phase on the growth and bacteriocin production of L. curvatus LTH 1174. Aerating the culture during growth had no effect on biomass formation, but the oxidative stress caused a higher level of specific bacteriocin production and led to a metabolic shift toward acetic acid production. Anaerobic conditions, on the other hand, led to an increased biomass concentration and less growth inhibition. Also, higher maximum volumetric bacteriocin activities and a higher level of specific bacteriocin production were obtained in the presence of sodium nitrite than in fermentations under aerobic conditions or standard conditions of air supply. These results indicate that the inhibitory effect of the curing agent is at least partially masked under anaerobic conditions. PMID:12839751

The curing agent sodium nitrite, used in the production of fermented sausages, is less inhibiting to the bacteriocin-producing meat starter culture Lactobacillus curvatus LTH 1174 under anaerobic conditions.

Science.gov (United States)

Verluyten, Jurgen; Messens, Winy; De Vuyst, Luc

2003-07-01

Curvacin A is a listericidal bacteriocin produced by Lactobacillus curvatus LTH 1174, a strain isolated from fermented sausage. The response of this strain to an added curing agent (sodium nitrite) in terms of cell growth and bacteriocin production was investigated in vitro by laboratory fermentations with modified MRS broth. The strain was highly sensitive to nitrite; even a concentration of 10 ppm of curing agent inhibited its growth and both volumetric and specific bacteriocin production. A meat simulation medium containing 5 ppm of sodium nitrite was tested to investigate the influence of the gas phase on the growth and bacteriocin production of L. curvatus LTH 1174. Aerating the culture during growth had no effect on biomass formation, but the oxidative stress caused a higher level of specific bacteriocin production and led to a metabolic shift toward acetic acid production. Anaerobic conditions, on the other hand, led to an increased biomass concentration and less growth inhibition. Also, higher maximum volumetric bacteriocin activities and a higher level of specific bacteriocin production were obtained in the presence of sodium nitrite than in fermentations under aerobic conditions or standard conditions of air supply. These results indicate that the inhibitory effect of the curing agent is at least partially masked under anaerobic conditions.

Anaerobic acidification of sugar-containing wastewater for biotechnological production of organic acids and ethanol.

Science.gov (United States)

Darwin; Charles, Wipa; Cord-Ruwisch, Ralf

2018-05-03

Anaerobic acidification of sugars can produce some useful end-products such as alcohol, volatile fatty acids (e.g. acetate, propionate, and butyrate) and lactic acid. The production of end-products is highly dependent on factors including pH, temperature, hydraulic retention time and the types of sugar being fermented. Results of this current study indicate that the pH and hydraulic retention time played significant roles in determining the end products from the anaerobic acidification of maltose and glucose. Under uncontrolled pH, the anaerobic acidification of maltose ceased when pH in the reactor dropped below 5 while anaerobic acidification of glucose continued and produced ethanol as the main end-product. Under controlled pH, lactic acid was found to be the dominant end-product produced from both maltose and glucose at pH 5. Acetate was the main end-product from both maltose and glucose fermented at neutral pH (6 and 7). Short hydraulic retention time (HRT) of 2 days could induce the production of ethanol from the anaerobic acidification of glucose. However, the anaerobic acidification of maltose could stop when short HRT of 2 days was applied in the reactor. This finding is significant for industrial fermentation and waste management systems, and selective production of different types of organic acids could be achieved by managing pH and HRT in the reactor.

Characterization of Spartina alterniflora as feedstock for anaerobic digestion

International Nuclear Information System (INIS)

Yang, Shiguan; Zheng, Zheng; Meng, Zhuo; Li, Jihong

2009-01-01

Smooth cordgrass (Spartina alterniflora), a saltmarsh plant with high production, was characterized for its potential for use as feedstock for anaerobic digestion processes. The anaerobic digestibility and biogas yield of S. alterniflora were evaluated by anaerobic batch digestion experiments performed at 35 ± 1 C at initial volatile solids (VS) of 6%. The nutrient content analysis indicated that S. alterniflora contained the required nutrition for anaerobic microorganisms, but its high C/N of 58.8, high K and Na contents of 8.1, 22.7 g kg -1 , respectively, may be disadvantageous to its anaerobic digestion. The cumulative biogas yield was determined to be 358 L kg -1 VS and the biodegradation efficiency was 45% after 60 days of digestion. The methane content of biogas increased from 53% on day 3 to around 62% after 13 days of digestion. The changes of volatile fatty acids (VFAs) indicated that the acidification of S. alterniflora was propionate-type fermentation with proportion of acetate and propionate ranging from 54.8% to 98.4%, and the hydrolysis of lignocellulose was the rate-limiting step for its anaerobic digestion. The analysis of cations suggested that K + and Mg 2+ , with the maximum concentration of 1.35 and 0.43 g L -1 in fermentation liquor, respectively, could be inhibitory to the anaerobic digestion of S. alterniflora. It is concluded that S. alterniflora can be transformed into clean energy by anaerobic digestion and the high contents of K, Na, Ca and Mg may be the inhibitory factors when S. alterniflora is digested by continuous or semi-continuous anaerobic process. (author)

The maximum specific hydrogen-producing activity of anaerobic mixed cultures: definition and determination

Science.gov (United States)

Mu, Yang; Yang, Hou-Yun; Wang, Ya-Zhou; He, Chuan-Shu; Zhao, Quan-Bao; Wang, Yi; Yu, Han-Qing

2014-06-01

Fermentative hydrogen production from wastes has many advantages compared to various chemical methods. Methodology for characterizing the hydrogen-producing activity of anaerobic mixed cultures is essential for monitoring reactor operation in fermentative hydrogen production, however there is lack of such kind of standardized methodologies. In the present study, a new index, i.e., the maximum specific hydrogen-producing activity (SHAm) of anaerobic mixed cultures, was proposed, and consequently a reliable and simple method, named SHAm test, was developed to determine it. Furthermore, the influences of various parameters on the SHAm value determination of anaerobic mixed cultures were evaluated. Additionally, this SHAm assay was tested for different types of substrates and bacterial inocula. Our results demonstrate that this novel SHAm assay was a rapid, accurate and simple methodology for determining the hydrogen-producing activity of anaerobic mixed cultures. Thus, application of this approach is beneficial to establishing a stable anaerobic hydrogen-producing system.

The maximum specific hydrogen-producing activity of anaerobic mixed cultures: definition and determination.

Science.gov (United States)

Mu, Yang; Yang, Hou-Yun; Wang, Ya-Zhou; He, Chuan-Shu; Zhao, Quan-Bao; Wang, Yi; Yu, Han-Qing

2014-06-10

Fermentative hydrogen production from wastes has many advantages compared to various chemical methods. Methodology for characterizing the hydrogen-producing activity of anaerobic mixed cultures is essential for monitoring reactor operation in fermentative hydrogen production, however there is lack of such kind of standardized methodologies. In the present study, a new index, i.e., the maximum specific hydrogen-producing activity (SHAm) of anaerobic mixed cultures, was proposed, and consequently a reliable and simple method, named SHAm test, was developed to determine it. Furthermore, the influences of various parameters on the SHAm value determination of anaerobic mixed cultures were evaluated. Additionally, this SHAm assay was tested for different types of substrates and bacterial inocula. Our results demonstrate that this novel SHAm assay was a rapid, accurate and simple methodology for determining the hydrogen-producing activity of anaerobic mixed cultures. Thus, application of this approach is beneficial to establishing a stable anaerobic hydrogen-producing system.

Galactose oxidation using 13C in healthy and galactosemic children

Directory of Open Access Journals (Sweden)

D.R. Resende-Campanholi

2015-03-01

Full Text Available Galactosemia is an inborn error of galactose metabolism that occurs mainly as the outcome of galactose-1-phosphate uridyltransferase (GALT deficiency. The ability to assess galactose oxidation following administration of a galactose-labeled isotope (1-13C-galactose allows the determination of galactose metabolism in a practical manner. We aimed to assess the level of galactose oxidation in both healthy and galactosemic Brazilian children. Twenty-one healthy children and seven children with galactosemia ranging from 1 to 7 years of age were studied. A breath test was used to quantitate 13CO2 enrichment in exhaled air before and at 30, 60, and 120 min after the oral administration of 7 mg/kg of an aqueous solution of 1-13C-galactose to all children. The molar ratios of 13CO2 and 12CO2 were quantified by the mass/charge ratio (m/z of stable isotopes in each air sample by gas-isotope-ratio mass spectrometry. In sick children, the cumulative percentage of 13C from labeled galactose (CUMPCD in the exhaled air ranged from 0.03% at 30 min to 1.67% at 120 min. In contrast, healthy subjects showed a much broader range in CUMPCD, with values from 0.4% at 30 min to 5.58% at 120 min. The study found a significant difference in galactose oxidation between children with and without galactosemia, demonstrating that the breath test is useful in discriminating children with GALT deficiencies.

A study of the kinetics and the effect of trace elements on mixed anaerobic fermentative biogas production by ternary quadratic general rotary unitised design

International Nuclear Information System (INIS)

Zhang, Chenxiao; Lian, Jing; Jiang, Zongshan; Guo, Jianbo; Guo, Yankai; Gou, Chenye

2016-01-01

In this study the effect of trace elements on methanogenesis was investigated during mixed anaerobic fermentation using a single-factor experiment in the present study. The most effective concentrations of Fe"0, Fe"2"+, Co"2"+ and Ni"2"+ that were added were 1500, 250, 0.3 and 0.6 mg/L, respectively. The optimal trace element combination was 0.58 mg/L Ni"2"+, 1200 mg/L Fe"0 and 0.34 mg/L Co"2"+ by the ternary quadratic general rotary unitised design method. The degree of influence exerted by trace elements on the cumulative methane yields decreased in the order of Ni"2"+, Fe"0 and Co"2"+, and the maximum CH_4 yield was 241.6 mL/g volatile solids (VS), according to a regression equation. The non-dissolved organic carbon hydrolytic process showed a good fit with the first-order kinetic model. The maximum value of CH_4 was 312.87 mL/g VS. Compared to the control, the bioconversion efficiencies of CH_4 and CO_2 production increased by 36.76% and 74.50%, respectively, at the optimal trace element combination. The obtained results provide new knowledge for improvements in the efficiency of anaerobic fermentation biogas production

ANAEROBIC DIGESTION MODEL ANALYSIS OF THE FERMENTATION PROCESS IN PSYCHROPHILIC AND MESOPHILIC CHAMBER IN ACCORDANCE WITH THE AMOUNT OF BIOGAS SOURCED

Directory of Open Access Journals (Sweden)

Dariusz Zdebik

2015-03-01

Full Text Available The paper presents problems concerning the modelling of anaerobic sludge stabilization, with the additional substrate (waste transported, dairy butchery sewage in psychrophilic fermentation conditions in the range 10–20 °C and mesophilic at 35 °C. Simulation test was conducted in the two digesters. Results of the study allowed to evaluate the effectiveness of conducting these processes in separate chambers, i.e. the psychrophilic and mesophilic chamber. During the simulations, terms of obtaining volatile fatty acids and biogas in conjunction with the operating conditions of the chambers indicated.

Physiological and fermentation properties of Bacillus coagulans and a mutant lacking fermentative lactate dehydrogenase activity.

Science.gov (United States)

Su, Yue; Rhee, Mun Su; Ingram, Lonnie O; Shanmugam, K T

2011-03-01

Bacillus coagulans, a sporogenic lactic acid bacterium, grows optimally at 50-55 °C and produces lactic acid as the primary fermentation product from both hexoses and pentoses. The amount of fungal cellulases required for simultaneous saccharification and fermentation (SSF) at 55 °C was previously reported to be three to four times lower than for SSF at the optimum growth temperature for Saccharomyces cerevisiae of 35 °C. An ethanologenic B. coagulans is expected to lower the cellulase loading and production cost of cellulosic ethanol due to SSF at 55 °C. As a first step towards developing B. coagulans as an ethanologenic microbial biocatalyst, activity of the primary fermentation enzyme L-lactate dehydrogenase was removed by mutation (strain Suy27). Strain Suy27 produced ethanol as the main fermentation product from glucose during growth at pH 7.0 (0.33 g ethanol per g glucose fermented). Pyruvate dehydrogenase (PDH) and alcohol dehydrogenase (ADH) acting in series contributed to about 55% of the ethanol produced by this mutant while pyruvate formate lyase and ADH were responsible for the remainder. Due to the absence of PDH activity in B. coagulans during fermentative growth at pH 5.0, the l-ldh mutant failed to grow anaerobically at pH 5.0. Strain Suy27-13, a derivative of the l-ldh mutant strain Suy27, that produced PDH activity during anaerobic growth at pH 5.0 grew at this pH and also produced ethanol as the fermentation product (0.39 g per g glucose). These results show that construction of an ethanologenic B. coagulans requires optimal expression of PDH activity in addition to the removal of the LDH activity to support growth and ethanol production.

Biogasification of solid wastes by two-phase anaerobic fermentation

International Nuclear Information System (INIS)

Ghosh, S.; Vieitez, E.R.; Liu, T.; Kato, Y.

1997-01-01

Municipal, industrial and agricultural solid wastes, and biomass deposits, cause large-scale pollution of land and water. Gaseous products of waste decomposition pollute the air and contribute to global warming. This paper describes the development of a two-phase fermentation system that alleviates methanogenic inhibition encountered with high-solids feed, accelerates methane fermentation of the solid bed, and captures methane (renewable energy) for captive use to reduce global warming. The innovative system consisted of a solid bed reactor packed with simulated solid waste at a density of 160 kg/m 3 and operated with recirculation of the percolated culture (bioleachate) through the bed. A rapid onset of solids hydrolysis, acidification, denitrification and hydrogen gas formation was observed under these operating conditions. However, these fermentative reactions stopped at a total fatty acids concentration of 13,000 mg/l (as acetic) at pH 5, with a reactor head-gas composition of 75 percent carbon dioxide, 20 percent nitrogen, 2 percent hydrogen and 3 percent methane. Fermentation inhibition was alleviated by moving the bioleachate to a separate methane-phase fermenter, and recycling methanogenic effluents at pH 7 to the solid bed. Coupled operation of the two reactors promoted methanogenic conversion of the high-solids feed. (author)

Structural basis for binding of fluorinated glucose and galactose to Trametes multicolor pyranose 2-oxidase variants with improved galactose conversion.

Directory of Open Access Journals (Sweden)

Tien Chye Tan

Full Text Available Each year, about six million tons of lactose are generated from liquid whey as industrial byproduct, and optimally this large carbohydrate waste should be used for the production of value-added products. Trametes multicolor pyranose 2-oxidase (TmP2O catalyzes the oxidation of various monosaccharides to the corresponding 2-keto sugars. Thus, a potential use of TmP2O is to convert the products from lactose hydrolysis, D-glucose and D-galactose, to more valuable products such as tagatose. Oxidation of glucose is however strongly favored over galactose, and oxidation of both substrates at more equal rates is desirable. Characterization of TmP2O variants (H450G, V546C, H450G/V546C with improved D-galactose conversion has been given earlier, of which H450G displayed the best relative conversion between the substrates. To rationalize the changes in conversion rates, we have analyzed high-resolution crystal structures of the aforementioned mutants with bound 2- and 3-fluorinated glucose and galactose. Binding of glucose and galactose in the productive 2-oxidation binding mode is nearly identical in all mutants, suggesting that this binding mode is essentially unaffected by the mutations. For the competing glucose binding mode, enzyme variants carrying the H450G replacement stabilize glucose as the α-anomer in position for 3-oxidation. The backbone relaxation at position 450 allows the substrate-binding loop to fold tightly around the ligand. V546C however stabilize glucose as the β-anomer using an open loop conformation. Improved binding of galactose is enabled by subtle relaxation effects at key active-site backbone positions. The competing binding mode for galactose 2-oxidation by V546C stabilizes the β-anomer for oxidation at C1, whereas H450G variants stabilize the 3-oxidation binding mode of the galactose α-anomer. The present study provides a detailed description of binding modes that rationalize changes in the relative conversion rates of D

Structural basis for binding of fluorinated glucose and galactose to Trametes multicolor pyranose 2-oxidase variants with improved galactose conversion.

Science.gov (United States)

Tan, Tien Chye; Spadiut, Oliver; Gandini, Rosaria; Haltrich, Dietmar; Divne, Christina

2014-01-01

Each year, about six million tons of lactose are generated from liquid whey as industrial byproduct, and optimally this large carbohydrate waste should be used for the production of value-added products. Trametes multicolor pyranose 2-oxidase (TmP2O) catalyzes the oxidation of various monosaccharides to the corresponding 2-keto sugars. Thus, a potential use of TmP2O is to convert the products from lactose hydrolysis, D-glucose and D-galactose, to more valuable products such as tagatose. Oxidation of glucose is however strongly favored over galactose, and oxidation of both substrates at more equal rates is desirable. Characterization of TmP2O variants (H450G, V546C, H450G/V546C) with improved D-galactose conversion has been given earlier, of which H450G displayed the best relative conversion between the substrates. To rationalize the changes in conversion rates, we have analyzed high-resolution crystal structures of the aforementioned mutants with bound 2- and 3-fluorinated glucose and galactose. Binding of glucose and galactose in the productive 2-oxidation binding mode is nearly identical in all mutants, suggesting that this binding mode is essentially unaffected by the mutations. For the competing glucose binding mode, enzyme variants carrying the H450G replacement stabilize glucose as the α-anomer in position for 3-oxidation. The backbone relaxation at position 450 allows the substrate-binding loop to fold tightly around the ligand. V546C however stabilize glucose as the β-anomer using an open loop conformation. Improved binding of galactose is enabled by subtle relaxation effects at key active-site backbone positions. The competing binding mode for galactose 2-oxidation by V546C stabilizes the β-anomer for oxidation at C1, whereas H450G variants stabilize the 3-oxidation binding mode of the galactose α-anomer. The present study provides a detailed description of binding modes that rationalize changes in the relative conversion rates of D-glucose and D-galactose

Sequential intrahepatic metabolic effects of enteric galactose alimentation in newborn rats.

Science.gov (United States)

Kliegman, R M; Morton, S

1988-09-01

We determined metabolic responses after enteric galactose alimentation in 5- to 7-day-old newborn rats fasted for 24 h. The glycemic response was attenuated after enteric galactose feeding compared with the response after enteric glucose-fed rat pups. 14C radioactivity in blood from galactose-fed pups was reduced as counts in blood galactose were lower than counts in blood glucose in glucose-fed pups. Nonetheless within 15 min, [14C] from galactose appeared in blood glucose suggesting rapid conversion of galactose to glucose. The plasma insulin response was also attenuated after galactose feeding compared with the insulin response after enteric glucose. Hepatic glycogen content increased rapidly after enteric galactose feeding and was higher than after glucose feeding at 60, 120, and 180 min. Significant glycogen synthesis after oral glucose was delayed and occurred at 240 min. Carbon radioactivity in glycogen was higher in galactose fed pups between 15 and 360 min of the study. Serial determination of hepatic metabolites revealed an increase of galactose-1-phosphate levels after oral galactose at 240 and 300 min and a transient decline of ATP at 15 min. Other hepatic metabolites did not demonstrate significant differences between the two groups. These data suggest that hepatic glycogen synthesis is more rapid and occurs sooner after galactose than after glucose alimentation in previously fasted newborn rats. Galactose may enter a more direct pathway for neonatal hepatic glycogen synthesis. The relatively delayed entry of glucose label into hepatic glycogen and the delay of net glycogen synthesis after oral glucose suggest that glucose entry is not direct and may require further metabolism before incorporation into glycogen.(ABSTRACT TRUNCATED AT 250 WORDS)

Manufacturing of fuel gas and organic compost containing repellents for insects and other pests, by double fermentation

Energy Technology Data Exchange (ETDEWEB)

de Farias, R.

1976-07-27

Solid waste such as selected trash, harvest residues, and manure are fermented in 2 stages (aerobic fermentation at 80/sup 0/ for 8 to 15 days and anaerobic for 35 to 60 days) to produce a CH/sub 4/-contg. fuel gas with a calorific value of approx. 9500 cal/m/sup 3/, and an organic solid which has repellent effects on insects and other predators. The anaerobic fermentation is carried out in digestors with self-regulable hydraulic seals.

Energy consumption in fermentation processes

Energy Technology Data Exchange (ETDEWEB)

Bach, P

1984-01-01

The purpose of the present publication is to limit energy used to aerate the anaerobic fermentation processes. In yeast production the aeration process consumes the greatest part of the total energy required. A mathematical model, based on literature data, is presented for a yeast fermenter. the effect of various aeration and raw product strategies can be calculated. Simulation of yeast fermentation proves it to be independent of oxygen transport. However interaction between flow conditions and biological kinetics (glucose effect) is a limiting factor. With many feeding point the use of enegy for aeration (mixing) can be reduced to 1/3 of the present one.

[Isolation and characterization of Thermopirellula anaerolimosa gen. nov., sp. nov., an obligate anaerobic hydrogen-producing bacterium of the phylum Planctomycetes].

Science.gov (United States)

Liu, Dongying; Liu, Yi; Men, Xuehui; Guo, Qunqun; Guo, Rongbo; Qiu, Yanling

2012-08-04

To cultivate various yet-to-be cultured heterotrophs from anaerobic granule sludge, we used a selective culture medium with low concentrations of substrates supplemented a variety of antibiotics. An obligate anaerobic, thermophilic, hydrogen-producing bacterium, strain VM20-7(T), was isolated from an upflow anaerobic sludge blanket (UASB) reactor treating high-strength organic wastewater from isomerized sugar production processes. Cells of strain VM20-7(T) are non-motile, spherical, pear or teardrop shaped, occurring singly(o)r as aggregates (0.7 - 2.0 microm x 0.7 - 2.0 microm). Spore formation was not observed. Growth temperature ranges from 35 - 50 degrees C (optimum 45 degrees C), pH ranges from 6.0 - 8.3 (optimum 7.0 - 7.5) , NaCl tolerant concentration ranges from 0% - 0.5% (w/v, optimum 0% ). Nitrate, sulfate, thiosulfate, sulfite, elemental sulfur and Fe (III)-NTA were not used as terminal electron acceptors. Strain VM20-7(T) utilizes a wide range of carbohydrates, including glucose, maltose, ribose, xylose, sucrose, galactose, mannose, raffinose, pectin, yeast extract and xylan. Acetate and H2 are the main end products of glucose fermentation. The G + C content of the genomic DNA was 60.9 mol%. 16S rRNA gene sequence analysis revealed that it is related to the Pirellula-Rhodopirellula-Blastopirellula (PRB) clade within the order Planctomycetales (82.7 - 84.3% similarity with 16S rRNA genes of other known related species). The first obligate anaerobic bacterium within the phylum Planctomycetes was isolated with low concentration of carbohydrates and antibiotics. On the basis of the physiological and phylogenetic data, the name Thermopirellula anaerolimosa gen. nov. , sp. nov. is proposed for strain VM20-7(T) (= CGMCC 1.5169(T) = JCM 17478(T) = DSM 24165(T)).

Metabolism in anoxic permeable sediments is dominated by eukaryotic dark fermentation

DEFF Research Database (Denmark)

Bourke, Michael F.; Marriott, Philip J.; Glud, Ronnie N.

2017-01-01

Permeable sediments are common across continental shelves and are critical contributors to marine biogeochemical cycling. Organic matter in permeable sediments is dominated by microalgae, which as eukaryotes have different anaerobic metabolic pathways to prokaryotes such as bacteria and archaea....... Here we present analyses of flow-through reactor experiments showing that dissolved inorganic carbon is produced predominantly as a result of anaerobic eukaryotic metabolic activity. In our experiments, anaerobic production of dissolved inorganic carbon was consistently accompanied by large dissolved H....../hydrogenase pathway of fermentative eukaryotic H2 production, suggesting that pathway as the source of H2 and dissolved inorganic carbon production. Metabolomic analysis showed large increases in lipid production at the onset of anoxia, consistent with documented pathways of anoxic dark fermentation in microalgae...

Effect of hemicellulolytic enzymes on mesophilic methane fermentation

Energy Technology Data Exchange (ETDEWEB)

Oi, S; Matsui, Y; Iizuka, M; Yamamoto, T

1977-01-01

Mesophilic methane fermentation was examined using soybean seed coat, a waste from soybean processing for oil manufacture, with or without treatment with hemicellulolytic enzymes of Aspergillus niger, and the following results were obtained: (1) The methane fermentation bacteria acclimated to soybean seed coat medium were shown to consume monosaccharides and evolve methane in the following decreasing order: glucose, fructose, mannose > xylose, galactose, glucosamine, galacturonic acid > arabinose. The bacteria were also shown to form methane from a gas mixture of hydrogen and carbon dioxide. (2) In fermentation of soybean seed coat treated with the fungal enzyme, about 70% of the total sugar content as consumed in four weeks, and the gas evolution was about twice that without the fungal enzyme. The gas evolved was composed of 60% methane and 36% carbon dioxide. In general, vigorous evolution of hydrogen and carbon dioxide occurred at a very early stage of fermentation, and was followed by formation of methane. The maximum gas evolution of the enzyme-treated mash took place in 6 days while that of untreated mash occurred one week later. Chemical oxygen demand of the supernatant of the former mash was decreased by fermentation to 7.0% of the initial level.

Hepatic, renal, and total body galactose elimination in the pig

DEFF Research Database (Denmark)

Winkler, K; Henriksen, Jens Henrik Sahl; Tygstrup, N

1993-01-01

Galactose elimination capacity is used as a quantitative measure of liver function on the assumption that galactose elimination outside the liver is negligible or easily corrected for. The relationship between hepatic and extrahepatic removal of galactose was studied in anesthetized pigs during...... reabsorption (Tm 178 +/- 3.0 mumol/min, Km 3.8 +/- 0.9 mmol/l, n = 20). Metabolic conversion of galactose in the kidney was not demonstrable. At all concentrations studied (0.4-5.8 mmol/l), total galactose elimination from the body exceeded the sum of hepatic and renal elimination by approximately 100 mumol....../min, independent of the concentration. At blood concentrations usually used for clinical estimation of the galactose elimination capacity (approximately 4 mmol/l), hepatic removal in the pig accounted for 55% and renal removal for 30% of total removal; 15% of removal occurred in other organs. We conclude...

Utilization of steam- and explosion-decompressed aspen wood by some anaerobes

Energy Technology Data Exchange (ETDEWEB)

Khan, A W; Asther, M; Giuliano, C

1984-01-01

Tests made to study the suitability of using steam- and explosion-decompressed aspen wood as a substrate in anaerobic fermentations indicated that after washing with dilute NaOH it becomes less than 80% accessible to both mesophilic and thermophilic cellulolytic anaerobes and cellulases, compared with delignified, ball-milled pulp. After washing, this material was also suitable for the single-step conversion of cellulose to EtOH using cocultures consisting of cellulolytic and EtOH-producing saccharolytic anaerobes; and without and after washing by the use of cellulolytic enzymes and ethanologenic anaerobes.

Anaerobic digestion of cider apple residues

Energy Technology Data Exchange (ETDEWEB)

Contreras Lopez, A. (E.T.S.I.I., U.N.E.D., Madrid (Spain). Dept. Quimica Applicada a la Ingenieria); Lopez Bobo, R. (E.T.S. Ingeneiros Industriales, Asturias (Spain). Dept. de Energia)

1992-12-01

Apple residue from the cider industry is used here for anaerobic fermentation. The effect of retention time and volatile solids concentration on the production of biogas and methane was investigated by using continuously mixed anaerobic fermentors with a working volume of 1 1. The maximum proportions of biogas and methane obtained were 430 1 biogas/kg per day (12 days' retention time and 3% of volatile solids) and 281 1 of methane per day (a retention time of 30 days and 2% of volatile solids), respectively. (author)

A biochemically structured model for ethanol fermentation by Kluyveromyces marxianus: A batch fermentation and kinetic study

DEFF Research Database (Denmark)

Sansonetti, Sascha; Hobley, Timothy John; Calabrò, V.

2011-01-01

Anaerobic batch fermentations of ricotta cheese whey (i.e. containing lactose) were performed under different operating conditions. Ethanol concentrations of ca. 22gL−1 were found from whey containing ca. 44gL−1 lactose, which corresponded to up to 95% of the theoretical ethanol yield within 15h......, lactose, biomass and glycerol during batch fermentation could be described within a ca. 6% deviation, as could the yield coefficients for biomass and ethanol produced on lactose. The model structure confirmed that the thermodynamics considerations on the stoichiometry of the system constrain the metabolic...... coefficients within a physically meaningful range thereby providing valuable and reliable insight into fermentation processes....

Comparative Analysis of Performance and Microbial Characteristics Between High-Solid and Low-Solid Anaerobic Digestion of Sewage Sludge Under Mesophilic Conditions.

Science.gov (United States)

Lu, Qin; Yi, Jing; Yang, Dianhai

2016-01-01

High-solid anaerobic digestion of sewage sludge achieves highly efficient volatile solid reduction, and production of volatile fatty acid (VFA) and methane compared with conventional low-solid anaerobic digestion. In this study, the potential mechanisms of the better performance in high-solid anaerobic digestion of sewage sludge were investigated by using 454 high-throughput pyrosequencing and real-time PCR to analyze the microbial characteristics in sewage sludge fermentation reactors. The results obtained by 454 high-throughput pyrosequencing revealed that the phyla Chloroflexi, Bacteroidetes, and Firmicutes were the dominant functional microorganisms in high-solid and low-solid anaerobic systems. Meanwhile, the real-time PCR assays showed that high-solid anaerobic digestion significantly increased the number of total bacteria, which enhanced the hydrolysis and acidification of sewage sludge. Further study indicated that the number of total archaea (dominated by Methanosarcina) in a high-solid anaerobic fermentation reactor was also higher than that in a low-solid reactor, resulting in higher VFA consumption and methane production. Hence, the increased key bacteria and methanogenic archaea involved in sewage sludge hydrolysis, acidification, and methanogenesis resulted in the better performance of high-solid anaerobic sewage sludge fermentation.

Immobilized anaerobic fermentation for bio-fuel production by Clostridium co-culture.

Science.gov (United States)

Xu, Lei; Tschirner, Ulrike

2014-08-01

Clostridium thermocellum/Clostridium thermolacticum co-culture fermentation has been shown to be a promising way of producing ethanol from several carbohydrates. In this research, immobilization techniques using sodium alginate and alkali pretreatment were successfully applied on this co-culture to improve the bio-ethanol fermentation performance during consolidated bio-processing (CBP). The ethanol yield obtained increased by over 60 % (as a percentage of the theoretical maximum) as compared to free cell fermentation. For cellobiose under optimized conditions, the ethanol yields were approaching about 85 % of the theoretical efficiency. To examine the feasibility of this immobilization co-culture on lignocellulosic biomass conversion, untreated and pretreated aspen biomasses were also used for fermentation experiments. The immobilized co-culture shows clear benefits in bio-ethanol production in the CBP process using pretreated aspen. With a 3-h, 9 % NaOH pretreatment, the aspen powder fermentation yields approached 78 % of the maximum theoretical efficiency, which is almost twice the yield of the untreated aspen fermentation.

Optimization of fermentative hydrogen production from palm oil mill effluent in an up-flow anaerobic sludge blanket fixed film bioreactor

Directory of Open Access Journals (Sweden)

Parviz Mohammadi

2017-09-01

Full Text Available Response surface methodology with a central composite design was applied to optimize fermentative hydrogen production from palm oil mill effluent (POME in an upflow anaerobic sludge blanket fixed film reactor. In this study, the concurrent effects of up-flow velocity (Vup and feed flow rate (QF as independent operating variables on biological hydrogen production were investigated. A broad range of organic loading rate between 10 and 60 g COD L−1 d−1 was used as the operating variables. The dependent parameters as multiple responses were evaluated. Experimental results showed the highest value of yield at 0.31 L H2 g−1 COD was obtained at Vup and QF of 0.5 m h−1 and 1.7 L d−1, respectively. The optimum conditions for the fermentative hydrogen production using pre-settled POME were QF = 2.0–3.7 L d−1 and Vup = 1.5–2.3 m h−1. The experimental results agreed very well with the model prediction.

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.

Galactose oxidation using {sup 13}C in healthy and galactosemic children

Energy Technology Data Exchange (ETDEWEB)

Resende-Campanholi, D.R. [Departamento de Puericultura e Pediatria, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Porta, G. [Unidade de Hepatologia Pediátrica, Instituto da Criança Prof. Pedro de Alcântara, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil); Ferrioli, E.; Pfrimer, K. [Departamento de Clínica Médica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Ciampo, L.A. Del; Junior, J.S. Camelo [Departamento de Puericultura e Pediatria, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil)

2015-01-20

Galactosemia is an inborn error of galactose metabolism that occurs mainly as the outcome of galactose-1-phosphate uridyltransferase (GALT) deficiency. The ability to assess galactose oxidation following administration of a galactose-labeled isotope (1-{sup 13}C-galactose) allows the determination of galactose metabolism in a practical manner. We aimed to assess the level of galactose oxidation in both healthy and galactosemic Brazilian children. Twenty-one healthy children and seven children with galactosemia ranging from 1 to 7 years of age were studied. A breath test was used to quantitate {sup 13}CO{sub 2} enrichment in exhaled air before and at 30, 60, and 120 min after the oral administration of 7 mg/kg of an aqueous solution of 1-{sup 13}C-galactose to all children. The molar ratios of {sup 13}CO{sub 2} and {sup 12}CO{sub 2} were quantified by the mass/charge ratio (m/z) of stable isotopes in each air sample by gas-isotope-ratio mass spectrometry. In sick children, the cumulative percentage of {sup 13}C from labeled galactose (CUMPCD) in the exhaled air ranged from 0.03% at 30 min to 1.67% at 120 min. In contrast, healthy subjects showed a much broader range in CUMPCD, with values from 0.4% at 30 min to 5.58% at 120 min. The study found a significant difference in galactose oxidation between children with and without galactosemia, demonstrating that the breath test is useful in discriminating children with GALT deficiencies.

Thermophilic anaerobic fermentation of olive pulp for hydrogen and methane production: modelling of the anaerobic digestion process

DEFF Research Database (Denmark)

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

2006-01-01

the olive pulp; c) subsequent anaerobic treatment of the hydrogen-effluent with the simultaneous production of methane; and d) development of a mathematical model able to describe the anaerobic digestion of the olive pulp and the effluent of hydrogen producing process. Both continuous and batch experiments...

[3H] Thymidine incorporation to estimate growth rates of anaerobic bacterial strains

International Nuclear Information System (INIS)

Winding, A.

1992-01-01

The incorporation of [ 3 H] thymidine by axenic cultures of anaerobic bacteria was investigated as a means to measure growth. The three fermentative strains and one of the methanogenic strains tested incorporated [ 3 H] thymidine during growth. It is concluded that the [ 3 H] thymidine incorporation method underestimates bacterial growth in anaerobic environments

Proposal of law about the recovery and valorization of the gas coming from the anaerobic fermentation of organic wastes, renewable energy with a high potentiality; Proposition de Loi portant sur la recuperation et la valorisation du gaz issu de la fermentation anaerobie des dechets organiques, energie renouvelable a forte potentialite

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-12-15

The goal of this proposal of law is the systematic and mandatory capture and valorization of the methane coming from the anaerobic fermentation of municipal and agricultural wastes, and more generally coming from any activity generating gases with at least 25% of methane. (J.S.)

Novel Pathway for Alcoholic Fermentation of 8-Gluconolactone in the Yeast Saccharomyces bulderi

NARCIS (Netherlands)

Dijken, van J.P.; Tuijl, van A.; Luttik, M.A.H.; Middelhoven, W.J.; Pronk, J.T.

2002-01-01

Under anaerobic conditions, the yeast Saccharomyces bulderi rapidly ferments -gluconolactone to ethanol and carbon dioxide. We propose that a novel pathway for -gluconolactone fermentation operates in this yeast. In this pathway, -gluconolactone is first reduced to glucose via an NADPH-dependent

Production of lactic acid from sucrose: strain selection, fermentation, and kinetic modeling.

Science.gov (United States)

Lunelli, Betânia H; Andrade, Rafael R; Atala, Daniel I P; Wolf Maciel, Maria Regina; Maugeri Filho, Francisco; Maciel Filho, Rubens

2010-05-01

Lactic acid is an important product arising from the anaerobic fermentation of sugars. It is used in the pharmaceutical, cosmetic, chemical, and food industries as well as for biodegradable polymer and green solvent production. In this work, several bacterial strains were isolated from industrial ethanol fermentation, and the most efficient strain for lactic acid production was selected. The fermentation was conducted in a batch system under anaerobic conditions for 50 h at a temperature of 34 degrees C, a pH value of 5.0, and an initial sucrose concentration of 12 g/L using diluted sugarcane molasses. Throughout the process, pulses of molasses were added in order to avoid the cell growth inhibition due to high sugar concentration as well as increased lactic acid concentrations. At the end of the fermentation, about 90% of sucrose was consumed to produce lactic acid and cells. A kinetic model has been developed to simulate the batch lactic acid fermentation results. The data obtained from the fermentation were used for determining the kinetic parameters of the model. The developed model for lactic acid production, growth cell, and sugar consumption simulates the experimental data well.

Single stage anaerobic digestion process. Megas process. Final report

Energy Technology Data Exchange (ETDEWEB)

Malarich, M.

1985-12-01

The rate-limiting step in the anaerobic digestion of domestic sewage sludge and agricultural manures is usually considered the conversion of acetate to methane and carbon dioxide. Some reports have suggested that phase transfer of endproduct carbon dioxide from the liquid to gaseous state may be the overall rate-limiting step. Research to date has focused on batch fermentation studies at varying carbon dioxide partial pressures (pCO/sub 2/) using simple substrates such as glucose or acetate. The results indicate that lowering the pCO/sub 2/ may increase methane production and waste stabilization rates. This research was conducted using continuous fermentations. Continuous fermentations using a complex synthetic waste were performed over a five-month period. The results obtained failed to support the findings of earlier batch studies where methane production increased as pCO/sub 2/ decreased. No significant difference in methane production was found between anaerobic digestion at low pCO/sub 2/ (0.1 to 0.15 atm) and normal pCO/sub 2/ (0.4 to 0.5 atm). 15 refs., 8 figs., 2 tabs.

Nitrifying aerobic granular sludge fermentation for releases of carbon source and phosphorus: The role of fermentation pH.

Science.gov (United States)

Zou, Jinte; Pan, Jiyang; He, Hangtian; Wu, Shuyun; Xiao, Naidong; Ni, Yongjiong; Li, Jun

2018-07-01

The effect of fermentation pH (uncontrolled, 4 and 10) on the releases of carbon source and phosphorus from nitrifying aerobic granular sludge (N-AGS) was investigated. Meanwhile, metal ion concentration and microbial community characterization were explored during N-AGS fermentation. The results indicated that N-AGS fermentation at pH 10 significantly promoted the releases of soluble chemical oxygen demand (SCOD) and total volatile fatty acids (TVFAs). However, SCOD and TVFA released from N-AGS were inhibited at pH 4. Moreover, acidic condition promoted phosphorus release (mainly apatite) from N-AGS during anaerobic fermentation. Nevertheless, alkaline condition failed to increase phosphorus concentration due to the formation of chemical-phosphate precipitates. Compared with the previously reported flocculent sludge fermentation, N-AGS fermentation released more SCOD and TVFAs, possibly due to the greater extracellular polymeric substances content and some hydrolytic-acidogenic bacteria in N-AGS. Therefore, N-AGS alkaline fermentation facilitated the carbon source recovery, while N-AGS acidic fermentation benefited the phosphorus recovery. Copyright © 2018. Published by Elsevier Ltd.

Butanol production from wheat straw by simultaneous saccharification and fermentation using Clostridium beijerinckii: Part II-Fed-batch fermentation

International Nuclear Information System (INIS)

Qureshi, Nasib; Saha, Badal C.; Cotta, Michael A.

2008-01-01

In these studies, Clostridium beijerinckii P260 was used to produce butanol (acetone-butanol-ethanol, or ABE) from wheat straw (WS) hydrolysate in a fed-batch reactor. It has been demonstrated that simultaneous hydrolysis of WS to achieve 100% hydrolysis to simple sugars (to the extent achievable under present conditions) and fermentation to butanol is possible. In addition to WS, the reactor was fed with a sugar solution containing glucose, xylose, arabinose, galactose, and mannose. The culture utilized all of the above sugars. It was noticed that near the end of fermentation (286-533 h), the culture had difficulties utilizing xylose. As a result of supplemental sugar feed to the reactor, ABE productivity was improved by 16% as compared with previous studies. In our previous experiment on simultaneous saccharification of WS and fermentation to butanol, a productivity of 0.31 g L -1 h -1 was observed, while in the present studies a productivity of 0.36 g L -1 h -1 was observed. It should be noted that a productivity of 0.77 g L -1 h -1 was observed when the culture was highly active. The fed-batch fermentation was operated for 533 h. It should be noted that C. beijerinckii P260 can be used to produce butanol from WS in integrated fermentations

Studies on bio-hydrogen production of different biomass fermentation types using molasses wastewater as substrate

Energy Technology Data Exchange (ETDEWEB)

Liu, K.; Jiao, A.Y.; Rao, P.H. [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; Li, W. [Beijing Normal Univ., Beijing (China)

2010-07-01

Anaerobic fermentation technology was used to treat molasses wastewater. This study compared the hydrogen production capability of different fermentation types involving dark fermentation hydrogen production. The paper discussed the experiment including the results. It was found that the fermentation type changed by changing engineered control parameters in a continuous stirred tank reactor (CSTR). It was concluded that ethanol-type fermentation resulted in the largest hydrogen production capability, while butyric acid-type fermentation took second place followed by propionic acid-type fermentation.

Thermoanaerobacter pentosaceus sp. nov., an anaerobic, extreme thermophilic, high ethanol-yielding bacterium isolated from household waste

DEFF Research Database (Denmark)

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

2013-01-01

of approximately 0.5 µm. Optimal growth occurred at 70 °C and pH(25°C) 7, with a maximum growth rate of 0.1 h-1. DNA G+C content was 34.2 mol %. Strain DTU01(T) could ferment arabinose, cellobiose, fructose, galactose, glucose, inulin, lactose, mannose, melibiose, pectin, starch, sucrose, xylan, yeast extract...

Fermentative hydrogen production from liquid swine manure with glucose supplement using an anaerobic sequencing batch reactor

Science.gov (United States)

Wu, Xiao

2009-12-01

The idea of coupling renewable energy production and agricultural waste management inspired this thesis. The production of an important future fuel---hydrogen gas---from high strength waste stream-liquid swine manure---using anaerobic treatment processes makes the most sustainable sense for both wastewater utilization and energy generation. The objectives of this thesis were to develop a fermentation process for converting liquid swine manure to hydrogen and to maximize hydrogen productivity. Anaerobic sequencing batch reactor (ASBR) systems were constructed to carry out this fermentation process, and seed sludge obtained from a dairy manure anaerobic digester and pretreated by nutrient acclimation, heat and pH treatment was used as inoculum. High system stability was indicated by a short startup period of 12 days followed by stable hydrogen production, and successful sludge granulation occurred within 23 days of startup at a hydraulic retention time (HRT) of 24 hours. Operation at a progressively decreasing HRT from 24 to 8h gave rise to an increasing biogas production rate from 15.2-34.4L/d, while good linear relationships were observed between both total biogas and hydrogen production rates correlated to HRT, with R2 values of 0.993 and 0.997, respectively. The maximum hydrogen yield of 1.63 mol-H 2/mol-hexose-feed occurred at HRT of 16h, while the HRT of 12h was highly suggested to achieve both high production rate and efficient yield. Hexose utilization efficiencies over 98%, considerable hydrogen production rate up to 14.3 L/d and hydrogen percentage of off-gas up to 43% (i.e., a CO 2/H2 ratio of 1.2) with the absence of CH4 production throughout the whole course of experiment at a pH of 5.0 strongly validated the feasibility of the fermentative H2 production from liquid swine manure using an ASBR system. Ethanol as well as acetic, butyric and valeric acids were produced in the system accompanying the hydrogen production, with acetic acid being the dominant

The extent of co-metabolism of glucose and galactose by L. lactis changes with the expression of the lacSZ operon from Streptococcus thermophilus

DEFF Research Database (Denmark)

Solem, Christian; Købmann, Brian Jensen; Jensen, Peter Ruhdal

2008-01-01

The lactose transporter and β-galactosidase from Streptococcus thermophilus, encoded by the lacSZ operon, were introduced into the lactose-negative strain Lactococcus lactis MG1363 and the expression of the lacSZ operon was modulated by substitution of the native promoter with randomized synthetic...... promoters. A series of strains with various expression levels of lacSZ were examined for their fermentation of lactose. Strains with a high expression level were found to metabolize lactose in a similar manner to S. thermophilus, i.e. the galactose moiety of lactose was excreted to the growth medium...... and only glucose was metabolized in glycolysis. Interestingly, strains with low expression of the operon showed a mixed acid metabolism and co-metabolism of galactose and glucose. The lactose flux increased gradually with increasing expression of the lacSZ operon until an optimum was observed...

The glucose-galactose paradox in neonatal murine hepatic glycogen synthesis

International Nuclear Information System (INIS)

Kunst, C.; Kliegman, R.; Trindade, C.

1989-01-01

In adults glucose incorporation to glycogen is indirect after recycling from lactate. In neonates galactose entry to glycogen exceeds that for glucose, but the pathway is unknown. The pathway of hexose incorporation to glycogen was studied in 5-7-day-old rats and 6-h-old rats injected intraperitoneally (IP) with either double-labeled [6-3H]glucose (nonrecycling), [U-14C]glucose (recycling), or [6-3H]glucose and [U-14C]galactose in saline. In another group of pups, 1 g/kg of glucose or galactose was administered in addition to tracers to determine glycemia and net glycogen synthesis between 15 and 180 min after injection. Blood glucose increased from 3.4 +/- 0.4 to 8.5 +/- 1.5 mM in 5-7-day-old pups in response to IP glucose; there was no glycemic response to galactose, although galactose levels increased from 0.5 to 6.3 mM at 15 min. Hepatic glycogen increased after IP glucose from 14 +/- 2 at 15 min to 30 +/- 3 at 120 min (P less than 0.01), whereas after IP galactose glycogen was 44 +/- 6 mumol/g at 120 min (P less than 0.05). After IP glucose, 3H and 14C disintegration per minute in glycogen increased slowly with 14C exceeding 3H at 120 and 180 min. In contrast IP [14C]galactose resulted in a much greater peak of 14C incorporation into glycogen. The ratio of 3H to 14C in glycogen relative to the injectate after IP glucose decreased from 0.69 +/- 0.12 to 0.36 +/- 0.03 (P less than 0.01) between 15 to 180 min, whereas the ratio after galactose was 0.20 +/- 0.007 to 0.15 +/- 0.02 at these times. The 6-h-old pups also demonstrated augmented incorporation of [14C]galactose in glycogen relative to [3H-14C]glucose. In contrast to 5-7-day-old pups there was no evidence of glucose recycling in 6-h-old pups. In conclusion galactose entry into glycogen exceeds that for glucose and is not dependent on recycling

The effect of enteric galactose on neonatal canine carbohydrate metabolism

International Nuclear Information System (INIS)

Kliegman, R.M.; Miettinen, E.L.; Kalhan, S.C.; Adam, P.A.

1981-01-01

Newborn pups were assigned to a fasting group or to a group receiving intravenous glucose alimentation. Glucose turnover was determined during steady state equilibration of simultaneously infused [6- 3 H] glucose. Thereafter, pups from each group received 0.625 g/Kg of either oral [U- 14 C] galactose or [U- 14 C] glucose. In fasted or intravenously alimented pups enteric glucose resulted in a rapid and sustained elevation of blood glucose concentrations. Systemic appearance of 14 C label from enteric glucose increased rapidly as did the enrichment of blood [ 14 C] glucose specific activity. In those pups given enteric galactose, blood glucose values were equivalent to that in the glucose fed groups, however 14 C appearing in blood glucose and blood glucose specific activity was significantly lower. The peak values for rates of appearance and disappearance of systemic glucose were significantly lower in pups fed galactose than among pups fed glucose. Glucose clearance was also significantly lower in these pups despite equivalent plasma insulin responses. Among fasting pups hepatic glycogen content was significantly higher in those given either oral glucose or galactose when compared to a completely starved control group. In contrast, among alimented pups galactose administration significantly enhanced hepatic glycogen content compared to those fed glucose. In addition, hepatic glycogen synthase (glucose-6-phosphate independent) activity was increased only among alimented pups fed galactose when compared to completely fasted pups. In conclusion these data suggest that following gastrointestinal galactose administration, hepatic carbohydrate uptake is augmented while glycogen synthesis may be enhanced. Augmented glycogen synthesis following galactose administration may reflect alterations in hepatic glycogen synthase activity or enhanced hepatic carbohydrate uptake

Treatment of wastewaters and methane fermentation

Energy Technology Data Exchange (ETDEWEB)

Lescure, J P; Bourlet, P

1980-01-01

The laboratory, pilot plant, and industrial scale experiments were conducted on the anaerobic fermentation of spent sugar beet pulps and wastewater from wineries. The product of the fermentation was a gas typically containing CH/sub 4/ 65, CO/sub 2/ 15, H/sub 2/S 2.4, 0.3, N 0.8, and nonidentified substances 16.1 volume %. A 500 L pilot plant could process 10 kg/day of the spent beet pulp containing 20% solids and produce 500-600 L/day gas. The conversion of organic C was 66-91%.

Combined enzyme mediated fermentation of cellulose and xylose to ethanol by Schizosaccharomyces pombe, cellulase, [beta]-glucosidase, and xylose isomerase

Science.gov (United States)

Lastick, S.M.; Mohagheghi, A.; Tucker, M.P.; Grohmann, K.

1994-12-13

A process for producing ethanol from mixed sugar streams from pretreated biomass comprising xylose and cellulose using enzymes to convert these substrates to fermentable sugars; selecting and isolating a yeast Schizosaccharomyces pombe ATCC No. 2476, having the ability to ferment these sugars as they are being formed to produce ethanol; loading the substrates with the fermentation mix composed of yeast, enzymes and substrates; fermenting the loaded substrates and enzymes under anaerobic conditions at a pH range of between about 5.0 to about 6.0 and at a temperature range of between about 35 C to about 40 C until the fermentation is completed, the xylose being isomerized to xylulose, the cellulose being converted to glucose, and these sugars being concurrently converted to ethanol by yeast through means of the anaerobic fermentation; and recovering the ethanol. 2 figures.

Metabolomic response of a marine bacterium to 3,6-anhydro-l-galactose, the rare sugar from red macroalgae, as the sole carbon source.

Science.gov (United States)

Yun, Eun Ju; Yu, Sora; Kim, Sooah; Kim, Kyoung Heon

2018-03-20

Marine red macroalgae have received much attention as sustainable resources for producing bio-based products. Therefore, understanding the metabolic pathways of carbohydrates from red macroalgae, in fermentative microorganisms, is crucial for efficient bioconversion of the carbohydrates into bio-based products. Recently, the novel catabolic pathway of 3,6-anhydro-l-galactose (AHG), the main component of red macroalgae, was discovered in a marine bacterium, Vibrio sp. strain EJY3. However, the global metabolic network in response to AHG remains unclear. Here, the intracellular metabolites of EJY3 grown on AHG, glucose, or galactose were comparatively profiled using gas chromatography/time-of-flight mass spectrometry. The global metabolite profiling results revealed that the metabolic profile for AHG significantly differed from those for other common sugars. Specifically, the metabolic intermediate of the AHG pathway, 3,6-anhydrogalactonate, was detected during growth only in the presence of AHG; thus, the recently discovered key steps in AHG catabolism was found not to occur in the catabolism of other common sugars. Moreover, the levels of metabolic intermediates related to glycerolipid metabolism and valine biosynthesis were higher with AHG than those with other sugars. These comprehensive metabolomic analytical results for AHG in this marine bacterium can be used as the basis for having fermentative microbial strains to engineered to efficiently utilize AHG from macroalgal biomass. Copyright © 2018 Elsevier B.V. All rights reserved.

Effects of pH value and substrate concentration on hydrogen production from the anaerobic fermentation of glucose

Energy Technology Data Exchange (ETDEWEB)

Li, Zhi; Wang, Hui; Tang, Zongxun; Wang, Xiaofang [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry (Ministry of Education), Department of Chemisty, Northwest University, Xi' an 710069 (China); Bai, Jinbo [Lab. MSS/MAT, CNRS UMR 8579, Ecole Centrale Paris, 92295 Chatenay Malabry (France)

2008-12-15

A series of batch experiments were conducted to investigate the effects of pH and glucose concentrations on biological hydrogen production by using the natural sludge obtained from the bed of a local river as inoculant. Batch experiments numbered series I and II were designed at an initial and constant pH of 5.0-7.0 with 1.0 increment and four different glucose concentrations (5.0, 7.5, 10 and 20 g glucose/L). The results showed that the optimal condition for anaerobic fermentative hydrogen production is 7.5 g glucose/L and constant pH 6.0 with a maximum H{sub 2} production rate of 0.22 mol H{sub 2} mol{sup -1} glucose h{sup -1}, a cumulative H{sub 2} yield of 1.83 mol H{sub 2} mol{sup -1} glucose and a H{sub 2} percentage of 63 in biogas. (author)

Microbial production of bulk chemicals: development of anaerobic processes

NARCIS (Netherlands)

Weusthuis, R.A.; Lamot, I.; Oost, van der J.; Sanders, J.P.M.

2011-01-01

nnovative fermentation processes are necessary for the cost-effective production of bulk chemicals from renewable resources. Current microbial processes are either anaerobic processes, with high yield and productivity, or less-efficient aerobic processes. Oxygen utilization plays an important role

Enhanced hydrogen and 1,3-propanediol production from glycerol by fermentation using mixed cultures

KAUST Repository

Selembo, Priscilla A.; Perez, Joe M.; Lloyd, Wallis A.; Logan, Bruce E.

2009-01-01

The conversion of glycerol into high value products, such as hydrogen gas and 1,3-propanediol (PD), was examined using anaerobic fermentation with heat-treated mixed cultures. Glycerol fermentation produced 0.28 mol-H 2/mol-glycerol (72 mL-H2/g

Anaerobic digestion of municipal solid waste: Technical developments

Energy Technology Data Exchange (ETDEWEB)

Rivard, C.J. [National Renewable Energy Lab., Golden, CO (United States)

1996-01-01

The anaerobic biogasification of organic wastes generates two useful products: a medium-Btu fuel gas and a compost-quality organic residue. Although commercial-scale digestion systems are used to treat municipal sewage wastes, the disposal of solid organic wastes, including municipal solid wastes (MSW), requires a more cost-efficient process. Modern biogasification systems employ high-rate, high-solids fermentation methods to improve process efficiency and reduce capital costs. The design criteria and development stages are discussed. These systems are also compared with conventional low-solids fermentation technology.

Anaerobic digestion of thin stillage for energy recovery and water reuse in corn-ethanol plants.

Science.gov (United States)

Alkan-Ozkaynak, A; Karthikeyan, K G

2011-11-01

Recycling of anaerobically-digested thin stillage within a corn-ethanol plant may result in the accumulation of nutrients of environmental concern in animal feed coproducts and inhibitory organic materials in the fermentation tank. Our focus is on anaerobic digestion of treated (centrifugation and lime addition) thin stillage. Suitability of digestate from anaerobic treatment for reuse as process water was also investigated. Experiments conducted at various inoculum-to-substrate ratios (ISRs) revealed that alkalinity is a critical parameter limiting digestibility of thin stillage. An ISR level of 2 appeared optimal based on high biogas production level (763 mL biogas/g volatile solids added) and organic matter removal (80.6% COD removal). The digester supernatant at this ISR level was found to contain both organic and inorganic constituents at levels that would cause no inhibition to ethanol fermentation. Anaerobic digestion of treated-thin stillage can be expected to improve the water and energy efficiencies of dry grind corn-ethanol plants. Copyright © 2011 Elsevier Ltd. All rights reserved.

Phenotypic characteristics of nitrate and 3-nitro-1-propionate-respiring enzymes of the obligate respiratory anaerobe Denitrobacterium detoxificans

Science.gov (United States)

Anaerobic respiration consumes reducing equivalents generated during fermentation thereby contributing to the maintenance of hydrogen homoeostasis in gut ecosystems. Nitrate and 3-nitro-1-propionate (NPA) are acceptors used by the nonfermentative, rumen anaerobe, Denitrobacterium detoxificans, whic...

Transcriptome-based characterization of interactions between Saccharomyces cerevisiae and Lactobacillus delbrueckii subsp. bulgaricus in lactose-grown chemostat cocultures.

Science.gov (United States)

Mendes, Filipa; Sieuwerts, Sander; de Hulster, Erik; Almering, Marinka J H; Luttik, Marijke A H; Pronk, Jack T; Smid, Eddy J; Bron, Peter A; Daran-Lapujade, Pascale

2013-10-01

Mixed populations of Saccharomyces cerevisiae yeasts and lactic acid bacteria occur in many dairy, food, and beverage fermentations, but knowledge about their interactions is incomplete. In the present study, interactions between Saccharomyces cerevisiae and Lactobacillus delbrueckii subsp. bulgaricus, two microorganisms that co-occur in kefir fermentations, were studied during anaerobic growth on lactose. By combining physiological and transcriptome analysis of the two strains in the cocultures, five mechanisms of interaction were identified. (i) Lb. delbrueckii subsp. bulgaricus hydrolyzes lactose, which cannot be metabolized by S. cerevisiae, to galactose and glucose. Subsequently, galactose, which cannot be metabolized by Lb. delbrueckii subsp. bulgaricus, is excreted and provides a carbon source for yeast. (ii) In pure cultures, Lb. delbrueckii subsp. bulgaricus grows only in the presence of increased CO2 concentrations. In anaerobic mixed cultures, the yeast provides this CO2 via alcoholic fermentation. (iii) Analysis of amino acid consumption from the defined medium indicated that S. cerevisiae supplied alanine to the bacterium. (iv) A mild but significant low-iron response in the yeast transcriptome, identified by DNA microarray analysis, was consistent with the chelation of iron by the lactate produced by Lb. delbrueckii subsp. bulgaricus. (v) Transcriptome analysis of Lb. delbrueckii subsp. bulgaricus in mixed cultures showed an overrepresentation of transcripts involved in lipid metabolism, suggesting either a competition of the two microorganisms for fatty acids or a response to the ethanol produced by S. cerevisiae. This study demonstrates that chemostat-based transcriptome analysis is a powerful tool to investigate microbial interactions in mixed populations.

Phosphorus and short-chain fatty acids recovery from waste activated sludge by anaerobic fermentation: Effect of acid or alkali pretreatment.

Science.gov (United States)

Wu, Liang; Zhang, Cheng; Hu, Hui; Liu, Jianyong; Duan, Tengfei; Luo, Jinghuan; Qian, Guangren

2017-09-01

Waste activated sludge (WAS) was pretreated by acid or alkali to enhance the anaerobic fermentation (AF) for phosphorus (P) and short-chain fatty acids (SCFAs) release into the liquid simultaneously. With acid pretreatment, the released total P concentration achieved 120mg/L, which was 71.4% higher than that with alkali pretreatment. In addition, alkali pretreatment enhanced organic P release with about 35.3% of organic P in the solid being converted to inorganic P, while little had changed with acid pretreatment. The results also showed that acid and alkali pretreatment enhanced SCFAs production by 15.3 and 12.5times, respectively. Acid pretreatment could be preferred for simultaneous recovery of P and SCFAs by AF. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transient exposure to oxygen or nitrate reveals ecophysiology of fermentative and sulfate-reducing benthic microbial populations

NARCIS (Netherlands)

Saad, S.; Bhatnagar, S.; Tegetmeyer, H.E.; Geelhoed, J.S.; Strous, M.; Ruff, S.E.

2017-01-01

SummaryFor the anaerobic remineralization of organic matter inmarine sediments, sulfate reduction coupled to fer-mentation plays a key role. Here, we enriched sulfate-reducing/fermentative communities from intertidalsediments under defined conditions in continuousculture. We transiently exposed

Galactose metabolism plays a crucial role in biofilm formation by Bacillus subtilis.

Science.gov (United States)

Chai, Yunrong; Beauregard, Pascale B; Vlamakis, Hera; Losick, Richard; Kolter, Roberto

2012-01-01

Galactose is a common monosaccharide that can be utilized by all living organisms via the activities of three main enzymes that make up the Leloir pathway: GalK, GalT, and GalE. In Bacillus subtilis, the absence of GalE causes sensitivity to exogenous galactose, leading to rapid cell lysis. This effect can be attributed to the accumulation of toxic galactose metabolites, since the galE mutant is blocked in the final step of galactose catabolism. In a screen for suppressor mutants restoring viability to a galE null mutant in the presence of galactose, we identified mutations in sinR, which is the major biofilm repressor gene. These mutations caused an increase in the production of the exopolysaccharide (EPS) component of the biofilm matrix. We propose that UDP-galactose is the toxic galactose metabolite and that it is used in the synthesis of EPS. Thus, EPS production can function as a shunt mechanism for this toxic molecule. Additionally, we demonstrated that galactose metabolism genes play an essential role in B. subtilis biofilm formation and that the expressions of both the gal and eps genes are interrelated. Finally, we propose that B. subtilis and other members of the Bacillus genus may have evolved to utilize naturally occurring polymers of galactose, such as galactan, as carbon sources. Bacteria switch from unicellular to multicellular states by producing extracellular matrices that contain exopolysaccharides. In such aggregates, known as biofilms, bacteria are more resistant to antibiotics. This makes biofilms a serious problem in clinical settings. The resilience of biofilms makes them very useful in industrial settings. Thus, understanding the production of biofilm matrices is an important problem in microbiology. In studying the synthesis of the biofilm matrix of Bacillus subtilis, we provide further understanding of a long-standing microbiological observation that certain mutants defective in the utilization of galactose became sensitive to it. In this

Growth and ethanol fermentation ability on hexose and pentose sugars and glucose effect under various conditions in thermotolerant yeast Kluyveromyces marxianus.

Science.gov (United States)

Rodrussamee, Nadchanok; Lertwattanasakul, Noppon; Hirata, Katsushi; Suprayogi; Limtong, Savitree; Kosaka, Tomoyuki; Yamada, Mamoru

2011-05-01

Ethanol fermentation ability of the thermotolerant yeast Kluyveromyces marxianus, which is able to utilize various sugars including glucose, mannose, galactose, xylose, and arabinose, was examined under shaking and static conditions at high temperatures. The yeast was found to produce ethanol from all of these sugars except for arabinose under a shaking condition but only from hexose sugars under a static condition. Growth and sugar utilization rate under a static condition were slower than those under a shaking condition, but maximum ethanol yield was slightly higher. Even at 40°C, a level of ethanol production similar to that at 30°C was observed except for galactose under a static condition. Glucose repression on utilization of other sugars was observed, and it was more evident at elevated temperatures. Consistent results were obtained by the addition of 2-deoxyglucose. The glucose effect was further examined at a transcription level, and it was found that KmGAL1 for galactokinase and KmXYL1 for xylose reductase for galactose and xylose/arabinose utilization, respectively, were repressed by glucose at low and high temperatures, but KmHXK2 for hexokinase was not repressed. We discuss the possible mechanism of glucose repression and the potential for utilization of K. marxianus in high-temperature fermentation with mixed sugars containing glucose.

Growth and ethanol fermentation ability on hexose and pentose sugars and glucose effect under various conditions in thermotolerant yeast Kluyveromyces marxianus

Energy Technology Data Exchange (ETDEWEB)

Rodrussamee, Nadchanok; Hirata, Katsushi; Suprayogi [Yamaguchi Univ., Ube (Japan). Graduate School of Medicine; Lertwattanasakul, Noppon; Kosaka, Tomoyuki [Yamaguchi Univ. (Japan). Faculty of Agriculture; Limtong, Savitree [Kasetsart Univ., Bangkok (Thailand). Faculty of Science; Yamada, Mamoru [Yamaguchi Univ., Ube (Japan). Graduate School of Medicine; Yamaguchi Univ. (Japan). Faculty of Agriculture

2011-05-15

Ethanol fermentation ability of the thermotolerant yeast Kluyveromyces marxianus, which is able to utilize various sugars including glucose, mannose, galactose, xylose, and arabinose, was examined under shaking and static conditions at high temperatures. The yeast was found to produce ethanol from all of these sugars except for arabinose under a shaking condition but only from hexose sugars under a static condition. Growth and sugar utilization rate under a static condition were slower than those under a shaking condition, but maximum ethanol yield was slightly higher. Even at 40 C, a level of ethanol production similar to that at 30 C was observed except for galactose under a static condition. Glucose repression on utilization of other sugars was observed, and it was more evident at elevated temperatures. Consistent results were obtained by the addition of 2-deoxyglucose. The glucose effect was further examined at a transcription level, and it was found that KmGAL1 for galactokinase and KmXYL1 for xylose reductase for galactose and xylose/arabinose utilization, respectively, were repressed by glucose at low and high temperatures, but KmHXK2 for hexokinase was not repressed. We discuss the possible mechanism of glucose repression and the potential for utilization of K. marxianus in high-temperature fermentation with mixed sugars containing glucose. (orig.)

Kinetic Analysis of Guanidine Hydrochloride Inactivation of β-Galactosidase in the Presence of Galactose

Directory of Open Access Journals (Sweden)

Charles O. Nwamba

2012-01-01

Full Text Available Inactivation of purified β-Galactosidase was done with GdnHCl in the absence and presence of varying [galactose] at 50°C and at pH 4.5. Lineweaver-Burk plots of initial velocity data, in the presence and absence of guanidine hydrochloride (GdnHCl and galactose, were used to determine the relevant and max values, with p-nitrophenyl β-D-galactopyranoside (pNPG as substrate, S. Plots of ln([]∞−[] against time in the presence of GdnHCl yielded the inactivation rate constant, A. Plots of A versus [S] at different galactose concentrations were straight lines that became increasingly less steep as the [galactose] increased, showing that A was dependent on [S]. Slopes and intercepts of the 1/[]∞ versus 1/[] yielded +0 and ′+0, the microscopic rate constants for the free enzyme and the enzyme-substrate complex, respectively. Plots of +0 and ′+0 versus [galactose] showed that galactose protected the free enzyme as well as the enzyme-substrate complex (only at the lowest and highest [galactose] against GdnHCl inactivation. In the absence of galactose, GdnHCl exhibited some degree of non-competitive inhibition. In the presence of GdnHCl, galactose exhibited competitive inhibition at the lower [galactose] of 5 mM which changed to non-competitive as the [galactose] increased. The implications of our findings are further discussed.

Developments and constraints in fermentative hydrogen production

NARCIS (Netherlands)

Bartacek, J.; Zabranska, J.; Lens, P.N.L.

2007-01-01

Fermentative hydrogen production is a novel aspect of anaerobic digestion. The main advantage of hydrogen is that it is a clean and renewable energy source/carrier with high specific heat of combustion and no contribution to the Greenhouse effect, and can be used in many industrial applications.

SU-F-T-677: Synergistic Effect(s) of Clotrimazole On Radiation Cell Survival of A549 Lung Cancer Cells in Glucose Vs. Galactose Media

Energy Technology Data Exchange (ETDEWEB)

Boss, G; Tambasco, M; Garakani, M [San Diego State University, San Diego, CA (United States)

2016-06-15

Purpose: In order to determine the synergistic effect of clotrimazole on radiosensitivity of A549 lung cancer cells, and the effect of oxidative pathways on modulating radiosensitivity, we studied how these cells survived under varying amounts of radiation and clotrimazole as well ass when glucose was switched for galactose media. Methods: The glucose media was used to determine the presence of any synergistic effect of clotrimazole on radiation using values of radiation and clotrimazole concentrations, varying from 0 – 8 Gy and 0 – 20 µM, respectively. As a galactose diet is known to activate oxidative pathways, which do not rely on hexokinase II (HK2), all trials were repeated using galactose media to determine the extent that HK2 unbinding from the mitochondrial membrane plays a role in modulating the observed radiosensitivity. An apoptosis vs. necrosis assay was implemented to find out the modality by which cell death occurred. An intracellular lactate assay was performed to exhibit the extent of anaerobic glycolysis. Results: After running the primary experiments, it was found that in glucose media, the cancer cells showed higher cell kill when clotrimazole was added to the media, followed by the cells being irradiated. Conclusion: Given the preliminary results it is validated that under higher concentrations of clotrimazole, in glucose media, A549 lung cancer cells exhibit a lower amount of survival. While all results have not yet been gathered. We anticipate that in galactose media the A549 cells will exhibit this effect to a much smaller degree, if at all.

Hydrogen gas production by fermentation from various organic wastewater using Clostridium butyricum NCIB 9576 and Rhodopseudomonas sphaeroides E15-1

Energy Technology Data Exchange (ETDEWEB)

Yoon, Young Sue; Kim, Hyun Kyung; Rye, Hye Yeon; Lee, In Gu; Kim, Mi Sun [Biomass Research Team, Korea Institute of Energy Research, Taejeon (Korea)

2000-03-01

Anaerobic fermentation using Clostidium butyricum NCIB 9576, and phto-fermentation using Rhodopseudomonas sphaeroides E15-1 were studied for the production of hydrogen from Makkoli, fruits (orange and apple, watermelon and melon) and Tofu wastewaters. From the Makkoli wastewater, which contained 0.94 g/liter sugars and 2.74 g/liter solubel starch, approximately 49 mM H{sub 2}/liter wastewater was produced during the initial 18h of the anaerobic fermentation with pH control between 6.5-7.0. Several organic acids such as butyric acid, acetic acid, propionic acid, lactic acid and ethanol were also produced. From watermelon and melon wastewater, which contained 43 g/liter sugars, generated about approximately 71 mM H{sub 2}/liter wastewater was produced during the initial 24h of the anaerobic fermentation. Tofu wastewater, pH 6.5, containing 12.6 g/liter soluble starch and 0.74 g/liter sugars, generated about 30mM H{sub 2}/liter wastewater, along with some organic acids, during the initial 24 h of anaerobic fermentation. Makkoli and Tofu wastewaters as substrates for the photo-fermentation by Rhodopseudomonas sphaeroides E15-1 produced approximately 37.9 and 22.2 {mu}M H{sub 2}/ml wastewaters, respectively for 9 days of incubation under the average of 9,000010,000 lux illumination at the surface of reactor using tungsten halogen lamps. Orange and apple wastewater, which contained 93.4 g/l produced approximately 13.1 {mu}M H{sub 2}/ml wastewater only for 2 days of photo-fermentation and the growth of Rhodopseudomonas spnaeroides E15-1 and hydrogen production were stopped. 22 refs, 4 figs., 2 tabs.

Evolution from a respiratory ancestor to fill syntrophic and fermentative niches: comparative fenomics of six Geobacteraceae species

Directory of Open Access Journals (Sweden)

Lovley Derek R

2009-03-01

Full Text Available Abstract Background The anaerobic degradation of organic matter in natural environments, and the biotechnical use of anaerobes in energy production and remediation of subsurface environments, both require the cooperative activity of a diversity of microorganisms in different metabolic niches. The Geobacteraceae family contains members with three important anaerobic metabolisms: fermentation, syntrophic degradation of fermentation intermediates, and anaerobic respiration. Results In order to learn more about the evolution of anaerobic microbial communities, the genome sequences of six Geobacteraceae species were analyzed. The results indicate that the last common Geobacteraceae ancestor contained sufficient genes for anaerobic respiration, completely oxidizing organic compounds with the reduction of external electron acceptors, features that are still retained in modern Geobacter and Desulfuromonas species. Evolution of specialization for fermentative growth arose twice, via distinct lateral gene transfer events, in Pelobacter carbinolicus and Pelobacter propionicus. Furthermore, P. carbinolicus gained hydrogenase genes and genes for ferredoxin reduction that appear to permit syntrophic growth via hydrogen production. The gain of new physiological capabilities in the Pelobacter species were accompanied by the loss of several key genes necessary for the complete oxidation of organic compounds and the genes for the c-type cytochromes required for extracellular electron transfer. Conclusion The results suggest that Pelobacter species evolved parallel strategies to enhance their ability to compete in environments in which electron acceptors for anaerobic respiration were limiting. More generally, these results demonstrate how relatively few gene changes can dramatically transform metabolic capabilities and expand the range of environments in which microorganisms can compete.

Anaerobes as Sources of Bioactive Compounds and Health Promoting Tools.

Science.gov (United States)

Mamo, Gashaw

Aerobic microorganisms have been sources of medicinal agents for several decades and an impressive variety of drugs have been isolated from their cultures, studied and formulated to treat or prevent diseases. On the other hand, anaerobes, which are believed to be the oldest life forms on earth and evolved remarkably diverse physiological functions, have largely been neglected as sources of bioactive compounds. However, results obtained from the limited research done so far show that anaerobes are capable of producing a range of interesting bioactive compounds that can promote human health. In fact, some of these bioactive compounds are found to be novel in their structure and/or mode of action.Anaerobes play health-promoting roles through their bioactive products as well as application of whole cells. The bioactive compounds produced by these microorganisms include antimicrobial agents and substances such as immunomodulators and vitamins. Bacteriocins produced by anaerobes have been in use as preservatives for about 40 years. Because these substances are effective at low concentrations, encounter relatively less resistance from bacteria and are safe to use, there is a growing interest in these antimicrobial agents. Moreover, several antibiotics have been reported from the cultures of anaerobes. Closthioamide and andrimid produced by Clostridium cellulolyticum and Pantoea agglomerans, respectively, are examples of novel antibiotics of anaerobe origin. The discovery of such novel bioactive compounds is expected to encourage further studies which can potentially lead to tapping of the antibiotic production potential of this fascinating group of microorganisms.Anaerobes are widely used in preparation of fermented foods and beverages. During the fermentation processes, these organisms produce a number of bioactive compounds including anticancer, antihypertensive and antioxidant substances. The well-known health promoting effect of fermented food is mostly due to these

Towards environmentally sustainable aquaculture: Exploiting fermentation products from anaerobic sludge digestion for fueling nitrate removal in RAS

DEFF Research Database (Denmark)

Suhr, Karin Isabel; Pedersen, Per Bovbjerg

2011-01-01

is by production in recirculating aquaculture systems (RAS). In Denmark, more than 50 % of total fresh-water rainbow trout production is made in semi-intensive RAS, called ModelTroutFarms (MTF). MTF efficiently removes organic matter (93%), phosphorous (76%), and nitrogen (50%) (Svendsen et al., 2008). This makes...... being the final cleaning component of the MTF set-up. No specific denitrification filter has so far been implemented in Danish MTFs. An in-situ study was conducted at a commercial MTF (1000 ton/year) for evaluating the potential of using the fermentation products from anaerobic digestion in the sludge...... time (HRT) from 50 to 180 min. The highest removal rate recorded, 125 g NO3-N/m3reactor/d, was found in treatments at the design center point, and multivariate response surface analysis modeled a maximum N-removal at C/N ratio of 8.8 and HRT of 114 min. The effect of C/N ratio depended on the HRT...

Galactose 6-sulfate sulfatase activity in Morquio syndrome

International Nuclear Information System (INIS)

Yutaka, T.; Okada, S.; Kato, T.; Inui, K.; Yabuuhi, H.

1982-01-01

The authors have prepared a new substrate, o-β-D-sulfo-galactosyl-(1-4)-β-D-6-sulfo-2-acetamido-2-deoxyglucosyl-(1-4)-D-[1- 3 H]galactitol, from shark cartilage keratan sulfate, for the assay of galactose 6-sulfate sulfatase activity. Using this substrate, they found there was a striking deficiency of galactose 6-sulfate sulfatase activity, in addition to the known deficiency of N-acetylgalactosamine 6-sulfate sulfatase, in the cultured skin fibroblasts of patients with Morquio syndrome. Their results could be explained by the hypothesis that accumulation of keratan sulfate and chondroitin 6-sulfate in Morquio syndrome is due to a deficiency of galactose 6-sulfate sulfatase and N-acetylgalactosamine 6-sulfate sulfatase activity, which are necessary for the degradation of these two mucopolysaccharides. (Auth.)

Galactose 6-sulfate sulfatase activity in Morquio syndrome

Energy Technology Data Exchange (ETDEWEB)

Yutaka, T.; Okada, S.; Kato, T.; Inui, K.; Yabuuhi, H. (Osaka Univ. (Japan). Faculty of Medicine)

1982-07-01

The authors have prepared a new substrate, o-..beta..-D-sulfo-galactosyl-(1-4)-..beta..-D-6-sulfo-2-acetamido-2-deoxyglucosyl-(1-4)-D-(1-/sup 3/H)galactitol, from shark cartilage keratan sulfate, for the assay of galactose 6-sulfate sulfatase activity. Using this substrate, they found there was a striking deficiency of galactose 6-sulfate sulfatase activity, in addition to the known deficiency of N-acetylgalactosamine 6-sulfate sulfatase, in the cultured skin fibroblasts of patients with Morquio syndrome. Their results could be explained by the hypothesis that accumulation of keratan sulfate and chondroitin 6-sulfate in Morquio syndrome is due to a deficiency of galactose 6-sulfate sulfatase and N-acetylgalactosamine 6-sulfate sulfatase activity, which are necessary for the degradation of these two mucopolysaccharides.

Anaerobic prefermentation and primary sedimentation of wastewater ...

African Journals Online (AJOL)

This research was carried out with the aim of evaluating the solubilisation and acidification capacity of fermenting organisms in suspension in a sequencing batch reactor (SBR), which had a volume of 1 800 ℓ. Using 8 h cycles with 340 min of anaerobic reaction time, the wastewater fed to the SBR presented an average of ...

Feasibility of enhancing short-chain fatty acids production from sludge anaerobic fermentation at free nitrous acid pretreatment: Role and significance of Tea saponin.

Science.gov (United States)

Xu, Qiuxiang; Liu, Xuran; Zhao, Jianwei; Wang, Dongbo; Wang, Qilin; Li, Xiaoming; Yang, Qi; Zeng, Guangming

2018-04-01

Short-chain fatty acids (SCFA), raw substrates for biodegradable plastic production and preferred carbon source for biological nutrients removal, can be produced from anaerobic fermentation of waste activated sludge (WAS). This paper reports a new, high-efficient and eco-friendly strategy, i.e., using free nitrous acid (FNA) pretreatment combined with Tea saponin (TS), to enhance SCFA production. Experimental results showed 0.90 mg/L FNA pretreatment and 0.05 g/g total suspended solids TS addition (FNA + TS) not only significantly increased SCFA production to 315.3 ± 8.8 mg COD/g VSS (5.52, 1.76 and 1.93 times higher than that from blank, solo FNA and solo TS, respectively) but also shortened fermentation time to 4 days. Mechanism investigations revealed that FNA pretreatment combined with TS cause a positive synergetic effect on sludge solubilization, resulting in more release of organics. It was also found that the combination benefited hydrolysis and acidogenesis processes but inhibited the methanogenesis. Copyright © 2018 Elsevier Ltd. All rights reserved.

Method for ph-controlled fermentation and biogas production

DEFF Research Database (Denmark)

2014-01-01

The present invention is in the field of biomass processing and bioenergy production and facilitates efficient biomass processing and an increased production of renewable energy from processing and anaerobic fermentation of a wide variety of organic materials. In order to control the pH value...

Microbiological fermentation of lignocellulosic biomass: current state and prospects of mathematical modeling.

Science.gov (United States)

Lübken, Manfred; Gehring, Tito; Wichern, Marc

2010-02-01

The anaerobic fermentation process has achieved growing importance in practice in recent years. Anaerobic fermentation is especially valuable because its end product is methane, a renewable energy source. While the use of renewable energy sources has accelerated substantially in recent years, their potential has not yet been sufficiently exploited. This is especially true for biogas technology. Biogas is created in a multistage process in which different microorganisms use the energy stored in carbohydrates, fats, and proteins for their metabolism. In order to produce biogas, any organic substrate that is microbiologically accessible can be used. The microbiological process in itself is extremely complex and still requires substantial research in order to be fully understood. Technical facilities for the production of biogas are thus generally scaled in a purely empirical manner. The efficiency of the process, therefore, corresponds to the optimum only in the rarest cases. An optimal production of biogas, as well as a stable plant operation requires detailed knowledge of the biochemical processes in the fermenter. The use of mathematical models can help to achieve the necessary deeper understanding of the process. This paper reviews both the history of model development and current state of the art in modeling anaerobic digestion processes.

Novel Wine Yeast for Improved Utilisation of Proline during Fermentation

Directory of Open Access Journals (Sweden)

Danfeng Long

2018-02-01

Full Text Available Proline is the predominant amino acid in grape juice, but it is poorly assimilated by wine yeast under the anaerobic conditions typical of most fermentations. Exploiting the abundance of this naturally occurring nitrogen source to overcome the need for nitrogen supplementation and/or the risk of stuck or sluggish fermentations would be most beneficial. This study describes the isolation and evaluation of a novel wine yeast isolate, Q7, obtained through ethyl methanesulfonate (EMS mutagenesis. The utilisation of proline by the EMS isolate was markedly higher than by the QA23 wild type strain, with approximately 700 and 300 mg/L more consumed under aerobic and self-anaerobic fermentation conditions, respectively, in the presence of preferred nitrogen sources. Higher intracellular proline contents in the wild type strain implied a lesser rate of proline catabolism or incorporation by this strain, but with higher cell viability after freezing treatment. The expression of key genes (PUT1, PUT2, PUT3, PUT4, GAP1 and URE2 involved in proline degradation, transport and repression were compared between the parent strain and the isolate, revealing key differences. The application of these strains for efficient conduct for nitrogen-limited fermentations is a possibility.

The anaerobic chytridiomycete fungus Piromyces sp. E2 produces ethanol via pyruvate:formate lyase and an alcohol dehydrogenase E.

NARCIS (Netherlands)

Boxma, B.; Voncken, F.L.M.; Jannink, S.A.; Alen, T.A. van; Akhmanova, A.S.; Weelden, S.W. van; Hellemond, J.J. van; Ricard, G.N.S.; Huynen, M.A.; Tielens, A.G.; Hackstein, J.H.P.

2004-01-01

Anaerobic chytridiomycete fungi possess hydrogenosomes, which generate hydrogen and ATP, but also acetate and formate as end-products of a prokaryotic-type mixed-acid fermentation. Notably, the anaerobic chytrids Piromyces and Neocallimastix use pyruvate:formate lyase (PFL) for the catabolism of

The use of a thermotolerant fermentative Kluyveromyces marxianus IMB3 yeast strain for ethanol production

Energy Technology Data Exchange (ETDEWEB)

Banat, I.M. [Univ. of the United Arab Emirates, Al-Ain (United Arab Emirates). Dept. of Biolology; Singh, D. [Haryana Agriculture Univ., Hisar (India). Dept. of Microbiology; Marchant, R. [Ulster Univ. (United Kingdom). School of Applied Biological and Chemical Sciences

1996-12-31

An investigation was carried out on the growth and ethanol production of a novel thermotolerant ethanol-producing Kluyveromyces marxianus IMB3 yeast strain. It grew aerobically on glucose, lactose, cellobiose, xylose and whey permeate and fermented all the above carbon sources to ethanol at 45 C. This strain was capable of growing under anaerobic chemostat fermentation conditions at 45 C and a dilution rate of 0.15 h{sup -1} and produced {<=}0.9 g/l biomass and 1.8% (v/v) ethanol. An increase in biomass (up to 10.0 g/l) and ethanol (up to 4.3% v/v at 45 C and 7.7% v/v at 40 C) were achieved by applying a continuous two-stage fermentation in sequence (one aerobic and one anerobic stage) or a two-stage anaerobic fermentation with cell recycling. Potential applications, involving alcohol production systems, for use in dairy and wood related industries, were discussed. (orig.)

Fermentation process using specific oxygen uptake rates as a process control

Science.gov (United States)

Van Hoek, Pim [Minnetonka, MN; Aristidou, Aristos [Maple Grove, MN; Rush, Brian [Minneapolis, MN

2011-05-10

Specific oxygen uptake (OUR) is used as a process control parameter in fermentation processes. OUR is determined during at least the production phase of a fermentation process, and process parameters are adjusted to maintain the OUR within desired ranges. The invention is particularly applicable when the fermentation is conducted using a microorganism having a natural PDC pathway that has been disrupted so that it no longer functions. Microorganisms of this sort often produce poorly under strictly anaerobic conditions. Microaeration controlled by monitoring OUR allows the performance of the microorganism to be optimized.

Modeling of fermentative hydrogen production from sweet sorghum extract based on modified ADM1

DEFF Research Database (Denmark)

Antonopoulou, Georgia; Gavala, Hariklia N.; Skiadas, Ioannis

2012-01-01

The Anaerobic digestion model 1 (ADM1) framework can be used to predict fermentative hydrogen production, since the latter is directly related to the acidogenic stage of the anaerobic digestion process. In this study, the ADM1 model framework was used to simulate and predict the process...... used for kinetic parameter validation. Since the ADM1 does not account for metabolic products such as lactic acid and ethanol that are crucial during the fermentative hydrogen production process, the structure of the model was modified to include lactate and ethanol among the metabolites and to improve...... of fermentative hydrogen production from the extractable sugars of sweet sorghum biomass. Kinetic parameters for sugars’ consumption and yield coefficients of acetic, propionic and butyric acid production were estimated using the experimental data obtained from the steady states of a CSTR. Batch experiments were...

Azo dye reduction by mesophilic and thermophilic anaerobic consortia

NARCIS (Netherlands)

Santos, dos A.B.; Madrid, de M.P.; Stams, A.J.M.; Lier, van J.B.; Cervantes, F.J.

2005-01-01

The reduction of the azo dye model compounds Reactive Red 2 (RR2) and Reactive Orange 14 (RO14) by mesophilic (30 C) and thermophilic (55 C) anaerobic consortia was studied in batch assays. The contribution of fermentative and methanogenic microorganisms in both temperatures was evaluated in the

Combined engineering of disaccharide transport and phosphorolysis for enhanced ATP yield from sucrose fermentation in Saccharomyces cerevisiae

NARCIS (Netherlands)

Marques, Wesley Leoricy; Mans, Robert; Henderson, Ryan K; Marella, Eko Roy; Horst, Jolanda Ter; Hulster, Erik de; Poolman, Bert; Daran, Jean-Marc; Pronk, Jack T; Gombert, Andreas K; van Maris, Antonius J A

Anaerobic industrial fermentation processes do not require aeration and intensive mixing and the accompanying cost savings are beneficial for production of chemicals and fuels. However, the free-energy conservation of fermentative pathways is often insufficient for the production and export of the

The use of galactose oxidase in lipid labeling

International Nuclear Information System (INIS)

Radin, N.S.; Evangelatos, G.P.

1981-01-01

Galactose oxidase can be used to oxidize the terminal carbon atom of lipids containing galactose or N-acetylgalactosamine, and the resultant aldehyde group can be reduced back to the original carbinol with radioactive borohydride. The efficiency of the first reaction has been investigated systematically by using [6- 3 H]galactosyl ceramide as substrate and measuring the amount of radioactive water formed. This enabled us to establish that the addition of catalase and peroxidase greatly speeded the oxidation, that phosphate and PIPES buffers were the best among those tested, that the reaction continued for 24 hr without a second addition of galactose oxidase, and that the optimum concentration of organic solvent (tetrahydrofuran) was 50%. The suggestion if made that a similar set of variables be studied for each lipid or nonlipid by the same basic technique: labeling by the oxidase/borohydride method and use of the resultant compound as substrate

Two Gene Clusters Coordinate Galactose and Lactose Metabolism in Streptococcus gordonii

Science.gov (United States)

Zeng, Lin; Martino, Nicole C.

2012-01-01

Streptococcus gordonii is an early colonizer of the human oral cavity and an abundant constituent of oral biofilms. Two tandemly arranged gene clusters, designated lac and gal, were identified in the S. gordonii DL1 genome, which encode genes of the tagatose pathway (lacABCD) and sugar phosphotransferase system (PTS) enzyme II permeases. Genes encoding a predicted phospho-β-galactosidase (LacG), a DeoR family transcriptional regulator (LacR), and a transcriptional antiterminator (LacT) were also present in the clusters. Growth and PTS assays supported that the permease designated EIILac transports lactose and galactose, whereas EIIGal transports galactose. The expression of the gene for EIIGal was markedly upregulated in cells growing on galactose. Using promoter-cat fusions, a role for LacR in the regulation of the expressions of both gene clusters was demonstrated, and the gal cluster was also shown to be sensitive to repression by CcpA. The deletion of lacT caused an inability to grow on lactose, apparently because of its role in the regulation of the expression of the genes for EIILac, but had little effect on galactose utilization. S. gordonii maintained a selective advantage over Streptococcus mutans in a mixed-species competition assay, associated with its possession of a high-affinity galactose PTS, although S. mutans could persist better at low pHs. Collectively, these results support the concept that the galactose and lactose systems of S. gordonii are subject to complex regulation and that a high-affinity galactose PTS may be advantageous when S. gordonii is competing against the caries pathogen S. mutans in oral biofilms. PMID:22660715

Moderate exercise prevents neurodegeneration in D-galactose-induced aging mice

Directory of Open Access Journals (Sweden)

Li Li

2016-01-01

Full Text Available D-galactose has been widely used in aging research because of its efficacy in inducing senescence and accelerating aging in animal models. The present study investigated the benefits of exercise for preventing neurodegeneration, such as synaptic plasticity, spatial learning and memory abilities, in mouse models of aging. D-galactose-induced aging mice were administered daily subcutaneous injections of D-galactose at the base of the neck for 10 consecutive weeks. Then, the mice were subjected to exercise training by running on a treadmill for 6 days a week. Shortened escape latency in a Morris water maze test indicated that exercise improved learning and memory in aging mice. The ameliorative changes were likely induced by an upregulation of Bcl-2 and brain-derived neurotrophic factor, the repression of apoptosis factors such as Fas and Bax, and an increase in the activity of glucose transporters-1 and 4. The data suggest moderate exercise may retard or inhibit neurodegeneration in D-galactose-induced aging mice.

Alcohol production by selected yeast strains in lactase-hydrolyzed acid whey

Energy Technology Data Exchange (ETDEWEB)

O' Leary, V S; Green, R; Sullivan, B C; Holsinger, V H

1977-07-01

Ethanol production by Kluyveromyces fragilis and Saccharomyces cerevisiae was studied using cottage cheese whey in which 80 to 90 percent of the lactose present had been prehydrolyzed to glucose and galactose. Complete fermentation of the sugar by K. fragilis required 120 hr at 30/sup 0/C in lactase-hydrolyzed whey compared to 72 hr in nonhydrolyzed whey. This effect was due to a diauxic fermentation pattern in lactase-hydrolyzed whey with glucose being fermented before galactose. Ethanol yields of about 2 percent were obtained in both types of whey when K. fragilis was the organism used for fermentation. Saccharomyces cerevisiae produced alcohol from glucose more rapidly than K. fragilis, but galactose was fermented only when S. cerevisiae was pregrown on galactose. Slightly lower alcohol yields were obtained with S. cerevisiae, owing to the presence of some lactose in the whey which was not fermented by this organism. Although prehydrolysis of lactose in whey and whey fractions is advantageous in that microbial species unable to ferment lactose may be utilized, diauxic and galactose utilization problems must be considered.

Impaired oxidation of carbon-labeled galactose by alcoholic or diabetic liver in vivo

International Nuclear Information System (INIS)

Shreeve, W.W.

1987-01-01

Because of the organ and enzyme specificity of the metabolism of galactose, evaluation of various kinds of liver disease can be done by measuring the formation of labeled breath CO 2 from carbon-labeld galactose in vivo. As shown earlier with uniformly 14 C- or 13 C-labeld galactose, a further study of alcoholic cirrhotic patients and controls with cheaper 1- 14 C-galactose indicates a superior discriminatory value of this test compared with common liver functions tests. The oxidation test is easier to perform and more acceptable to patients than the standard galactose tolerance blood test. Output of 14 CO 2 showed slight correlations with serum albumin and 99m Tc-sulfur colloid scan grade, but not with other function tests (SGOT, alkaline phosphatase, bilirubin). Comparison with five-year clinical outcome (two groups: with or without known liver-related death) in 29 of 43 total cirrhotic patients (U- 14 C or 1- 14 C-galactose) showed a low (75% probability) significance of prognosis for the galactose oxidation test, but none for any of the other tests. A two-part test of oxidation of 14 C-galactose (with and without an acute dose of ethanol) in 19 possibly or likely alcoholic (but non-cirrhotic) persons indicated, by correlation with other liver function tests and drinking history, some possibly enhanced sensitivity of the two-part versus the single test for recognizing early liver damage. A preliminary study of the single galactose oxidation test in 7 patients with Type II diabetes suggests moderate impairment of oxidation, which might be applied to evaluate the hepatic disorder in diabetes. (orig.) [de

Effects of IMOD and Angipars on Mouse D-Galactose-Induced Model of Aging

Directory of Open Access Journals (Sweden)

Samane Ghanbari

2012-10-01

Full Text Available The aim of this study was to evaluate the effects of two registered herbal drugs called IMOD and Angipars on mouse model of. Aging was induced by D-galactose (500 mg/kgadministered to animals for 6 weeks through drinking water. Male BALB/c mice were randomly divided into 5 groups receiving D-galactose (D-galactose, 500 mg/kg for 6 weeks; positive control (D-galactose [500 mg/kg] for 6 weeks + Vitamin E [200 mg/kg/day]intraperitoneally for 4 weeks; IMOD (D-galactose [500 mg/kg] for 6 weeks + IMOD [20 mg/kg/day] intraperitoneally for 4 weeks, Angipars (D-galactose [500 mg/kg] for 6 weeks + Angipars [2.1 mg/kg/day] by gavage for 4 weeks; and the fifth group that was sham and not given D-galactose. At the end of treatment, pro-inflammatory markers including tumor necrosis factor-α (TNF-α, interlukine-1β (IL-β, interlukine-6 (IL-6, NF-kappaB (NF-κb, total antioxidant power (TAP, lipid peroxides (LPO and male sex hormones i.e.testosterone and dehydroepiandrosterone-sulfate (DHEA-S were measured in the blood.Results showed that D-Galactose induces a significant oxidative stress and proinflammatory cascade of aging while both IMOD and Angipars recovered all of them. Interestingly, IMOD and Angipars were better than Vitamin E in improving male sex hormones that were declined in aged mice. This effect is so important and should be considered as an advantage although it cannot be explained with current knowledge. The conclusion is that IMOD and Angipars have marked anti-aging effect on D-galactose-induced model of aging.

Enhanced biogas yield from energy crops with rumen anaerobic fungi

Energy Technology Data Exchange (ETDEWEB)

Prochazka, Jindrich; Zabranska, Jana; Dohanyos, Michal [Department of Water Technology and Environmental Engineering, Faculty of Environmental Technology, Institute of Chemical Technology in Prague, Prague (Czech Republic); Mrazek, Jakub; Strosova, Lenka; Fliegerova, Katerina [Laboratory of Anaerobic Microbiology, Institute of Animal Physiology and Genetics, CAS, v.v.i., Prague (Czech Republic)

2012-06-15

Anaerobic fungi (AF) are able to degrade crop substrates with higher efficiency than commonly used anaerobic bacteria. The aim of this study was to investigate ways of use of rumen AF to improve biogas production from energy crops under laboratory conditions. In this study, strains of AF isolated from feces or rumen fluid of cows and deer were tested for their ability to integrate into the anaerobic bacterial ecosystem used for biogas production, in order to improve degradation of substrate polysaccharides and consequently the biogas yield. Batch culture, fed batch culture, and semicontinuous experiments have been performed using anaerobic sludge from pig slurry fermentation and different kinds of substrates (celluloses, maize, and grass silage) inoculated by different genera of AF. All experiments showed a positive effect of AF on the biogas yield and quality. AF improved the biogas production by 4-22%, depending on the substrate and AF species used. However, all the cultivation experiments indicated that rumen fungi do not show long-term survival in fermenters with digestate from pig slurry. The best results were achieved during fed batch experiment with fungal culture Anaeromyces (KF8), in which biogas production was enhanced during the whole experimental period of 140 days. This result has not been achieved in semicontinuous experiment, where increment in biogas production in fungal enriched reactor was only 4% after 42 days. (copyright 2012 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

In situ prebiotics for weaning piglets: In vitro production and fermentation of potato galactorhamnogalacturonan

DEFF Research Database (Denmark)

Strube, Mikael Lenz; Ravn, Helle Christine; Ingerslev, Hans-Christian

2015-01-01

Post weaning diarrhea (PWD) in pigs is a leading cause of economic loss in pork production worldwide. The current practice of using antibiotics and zinc to treat PWD is unsustainable due to the potential of antibiotic resistance and ecological disturbance, and novel methods are required...... product, with a minimal enzyme dose in a simulated upper GI-model extracting 26.9 % of initial dry matter. The fiber was rich in galactose and galacturonic acid and was fermented at 2.5, 5 or 10 g/L in a glucose-free media inoculated with the gut contents of piglet terminal ileum. Fermentations of 5 g....... For animal studies, a dosage corresponding to the 5 g/L treatment is suggested....

Low-Carbon Fuel and Chemical Production by Anaerobic Gas Fermentation.

Science.gov (United States)

Daniell, James; Nagaraju, Shilpa; Burton, Freya; Köpke, Michael; Simpson, Séan Dennis

World energy demand is expected to increase by up to 40% by 2035. Over this period, the global population is also expected to increase by a billion people. A challenge facing the global community is not only to increase the supply of fuel, but also to minimize fossil carbon emissions to safeguard the environment, at the same time as ensuring that food production and supply is not detrimentally impacted. Gas fermentation is a rapidly maturing technology which allows low carbon fuel and commodity chemical synthesis. Unlike traditional biofuel technologies, gas fermentation avoids the use of sugars, relying instead on gas streams rich in carbon monoxide and/or hydrogen and carbon dioxide as sources of carbon and energy for product synthesis by specialized bacteria collectively known as acetogens. Thus, gas fermentation enables access to a diverse array of novel, large volume, and globally available feedstocks including industrial waste gases and syngas produced, for example, via the gasification of municipal waste and biomass. Through the efforts of academic labs and early stage ventures, process scale-up challenges have been surmounted through the development of specialized bioreactors. Furthermore, tools for the genetic improvement of the acetogenic bacteria have been reported, paving the way for the production of a spectrum of ever-more valuable products via this process. As a result of these developments, interest in gas fermentation among both researchers and legislators has grown significantly in the past 5 years to the point that this approach is now considered amongst the mainstream of emerging technology solutions for near-term low-carbon fuel and chemical synthesis.

Anaerobic biological treatment

International Nuclear Information System (INIS)

Speece, R.E.

1990-01-01

The Enso-Fenox process has been very successfully used to remove chlorinated phenolic compounds from pulp bleaching effluents. It is a two-stage anaerobic/aerobic process consisting of a nonmethanogenic anaerobic fluidized bed followed by a trickling filter. Studies have been conducted on reductive dechlorination of chlorinated aromatic compounds under anaerobic conditions with chlorinated phenols as the sole carbon and energy source. Approximately 40% of the added chlorophenols was converted to CH 4 and CO 2 . Substrate loading rates were 20 mg/L/d at hydraulic detention times of 2-4 days with 90% substrate conversion efficiency. Reductive dechlorination of mono, di-, tri-, and pentachlorophenols has been demonstrated in anaerobic sewage sludge. The following constituents were tested in the laboratory at their approximate concentrations in coal conversion wastewater (CCWW) and were anaerobically degraded in serum bottles: 1,000 mg/L phenol; 500 mg/L resorcinol; 1,000 mg/L benzoic acid; 500 mg/L p-cresol; 200 mg/L pyridine; 2,000 mg/L benzoic acid; 250 mg/L 40 methylcatechol; 500 mg/L 4-ethylpyridine; and 2,000 mg/L hexanoic acid. A petrochemical may initially exhibit toxicity to an unacclimated population of methane-fermenting bacteria, but with acclimation the toxicity may be greatly reduced or disappear. In addition, the microorganisms may develop the capacity to actually degrade compounds which showed initial toxicity. Since biomass digestion requires a complete consortium of bacteria, it is relevant to study the effect of a given process as well as to individual steps within the process. A toxicant can inhibit the rate-limiting step and/or change the step that is rate-limiting. Both manifestations of toxicity can severely affect the overall process

Tolerance of anaerobic bacteria to chlorinated solvents.

Science.gov (United States)

Koenig, Joanna C; Groissmeier, Kathrin D; Manefield, Mike J

2014-01-01

The aim of this research was to evaluate the effects of four chlorinated aliphatic hydrocarbons (CAHs), perchloroethene (PCE), carbon tetrachloride (CT), chloroform (CF) and 1,2-dichloroethane (1,2-DCA), on the growth of eight anaerobic bacteria: four fermentative species (Escherichia coli, Klebsiella sp., Clostridium sp. and Paenibacillus sp.) and four respiring species (Pseudomonas aeruginosa, Geobacter sulfurreducens, Shewanella oneidensis and Desulfovibrio vulgaris). Effective concentrations of solvents which inhibited growth rates by 50% (EC50) were determined. The octanol-water partition coefficient or log Po/w of a CAH proved a generally satisfactory measure of its toxicity. Most species tolerated approximately 3-fold and 10-fold higher concentrations of the two relatively more polar CAHs CF and 1,2-DCA, respectively, than the two relatively less polar compounds PCE and CT. EC50 values correlated well with growth rates observed in solvent-free cultures, with fast-growing organisms displaying higher tolerance levels. Overall, fermentative bacteria were more tolerant to CAHs than respiring species, with iron- and sulfate-reducing bacteria in particular appearing highly sensitive to CAHs. These data extend the current understanding of the impact of CAHs on a range of anaerobic bacteria, which will benefit the field of bioremediation.

Enhanced volatile fatty acids production from anaerobic fermentation of food waste: A mini-review focusing on acidogenic metabolic pathways.

Science.gov (United States)

Zhou, Miaomiao; Yan, Binghua; Wong, Jonathan W C; Zhang, Yang

2018-01-01

Recently, efficient disposal of food waste (FW) with potential resource recovery has attracted great attentions. Due to its easily biodegradable nature, rich nutrient availability and high moisture content, FW is regarded as favorable substrate for anaerobic digestion (AD). Both waste disposal and energy recovery can be fulfilled during AD of FW. Volatile fatty acids (VFAs) which are the products of the first-two stages of AD, are widely applied in chemical industry as platform chemicals recently. Concentration and distribution of VFAs is the result of acidogenic metabolic pathways, which can be affected by the micro-environment (e.g. pH) in the digester. Hence, the clear elucidation of the acidogenic metabolic pathways is essential for optimization of acidogenic process for efficient product recovery. This review summarizes major acidogenic metabolic pathways and regulating strategies for enhancing VFAs recovery during acidogenic fermentation of FW. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of submerged and anaerobic fermentations on cassava flour ...

African Journals Online (AJOL)

Oke Oluwatoyin Victoria

2015-03-18

Mar 18, 2015 ... developed countries to transform and preserve food crops because of its low ... the tissues are softened and disintegration of the tissues by microorganisms ... characteristics of the products developed from the two fermentation ...

Galactose uncovers face recognition and mental images in congenital prosopagnosia: the first case report.

Science.gov (United States)

Esins, Janina; Schultz, Johannes; Bülthoff, Isabelle; Kennerknecht, Ingo

2014-09-01

A woman in her early 40s with congenital prosopagnosia and attention deficit hyperactivity disorder observed for the first time sudden and extensive improvement of her face recognition abilities, mental imagery, and sense of navigation after galactose intake. This effect of galactose on prosopagnosia has never been reported before. Even if this effect is restricted to a subform of congenital prosopagnosia, galactose might improve the condition of other prosopagnosics. Congenital prosopagnosia, the inability to recognize other people by their face, has extensive negative impact on everyday life. It has a high prevalence of about 2.5%. Monosaccharides are known to have a positive impact on cognitive performance. Here, we report the case of a prosopagnosic woman for whom the daily intake of 5 g of galactose resulted in a remarkable improvement of her lifelong face blindness, along with improved sense of orientation and more vivid mental imagery. All these improvements vanished after discontinuing galactose intake. The self-reported effects of galactose were wide-ranging and remarkably strong but could not be reproduced for 16 other prosopagnosics tested. Indications about heterogeneity within prosopagnosia have been reported; this could explain the difficulty to find similar effects in other prosopagnosics. Detailed analyses of the effects of galactose in prosopagnosia might give more insight into the effects of galactose on human cognition in general. Galactose is cheap and easy to obtain, therefore, a systematic test of its positive effects on other cases of congenital prosopagnosia may be warranted.

Utilization of steam- and explosion-decompressed aspen wood by some anaerobes. [Acetivibrio cellulolyticus, Clostridium saccharolyticum, Zymomonas anaerobia

Energy Technology Data Exchange (ETDEWEB)

Khan, A W; Asther, M; Giuliano, C

1984-01-01

Tests made to study the suitability of using steam- and explosion-decompressed aspen wood as substrate in anaerobic fermentations indicated that after washing with dilute NaOH it becomes over 80% accessible to both mesophilic and thermophilic cellulolytic anaerobes and cellulases, compared with delignified, ball-milled pulp. After washing, this material was also found to be suitable for the single-step conversion of cellulose to ethanol using cocultures consisting of cellylolytic and ethanol-producing saccharolytic anaerobes; and without and after washing by the use of cellulolytic enzymes and ethanologenic anaerobes. 16 references, 3 tables.

Identification of galactose as the immunodominant sugar of leishmanial excreted factor and subsequent labeling with galactose oxidase and sodium boro[3H]hydride.

Science.gov (United States)

Slutzky, G M; Greenblatt, C L

1982-01-01

Inhibition by low-molecular-weight sugars of precipitin line formation between a polysaccharide (EF) excreted by Leishmania tropica subsp. major, Leishmania enriettii, and rabbit antileishmanial antibodies on double gel diffusion plates revealed that galactose residues, possibly as components of lactosyl groups, were the critical immunodominant sugars mediating antibody recognition of EF. The galactose residues of the EF of L. tropica subsp. major were specifically labeled with tritium via galactose oxidase and sodium boro[3H]hydride. The radioactive EF had an apparent molecular weight of about 85,000 on sodium dodecyl sulfate-polyacrylamide gels and was precipitated by antileishmanial antibodies as well as Ricinus communis lectins I and II (galactose specific). Lectins specific for glucose-mannose residues, fucose, N-acetylglucosamine, and N-acetylgalactosamine did not precipitate the labeled EF. Treatment of [3H]EF with proteolytic (trypsin, papain, protease) or glycosidic (alpha-amylase, beta-galactosidase) enzymes had no effect on either the electrophoretic pattern of the material or on its recognition by antileishmanial antibodies or R. communis lectin. This resistance to enzyme activity suggests that EF may be a useful marker for the presence of the parasite in vivo if it can be detected in minute quantities. PMID:6179874

Anaerobic fluidized bed reactor with expanded clay as support for hydrogen production through dark fermentation of glucose

Energy Technology Data Exchange (ETDEWEB)

Cavalcante de Amorim, Eduardo Lucena [Department of Hydraulic and Sanitation, University of Sao Paulo. Av. Trabalhador Saocarlense, 400 Centro, CEP 13566-590 Sao Carlos, SP (Brazil); Barros, Aruana Rocha; Rissato Zamariolli Damianovic, Marcia Helena; Silva, Edson Luiz [Department of Chemical Engineering, Federal University of Sao Carlos, Rodovia Washington Luis, km 235, CEP 13565-905 Sao Carlos, SP (Brazil)

2009-01-15

This study evaluated hydrogen production in an anaerobic fluidized bed reactor (AFBR) fed with glucose-based synthetic wastewater. Particles of expanded clay (2.8-3.35 mm) were used as a support material for biomass immobilization. The reactor was operated with hydraulic retention times (HRT) ranging from 8 to 1 h. The hydrogen yield production increased from 1.41 to 2.49 mol H{sub 2} mol{sup -1} glucose as HRT decreased from 8 to 2 h. However, when HRT was 1 h, there was a slight decrease to 2.41 mol H{sub 2} mol{sup -1} glucose. The biogas produced was composed of H{sub 2} and CO{sub 2}, and the H{sub 2} content increased from 8% to 35% as HRT decreased. The major soluble metabolites during H{sub 2} fermentation were acetic acid (HAc) and butyric acid (HBu), accounting for 36.1-53.3% and 37.7-44.9% of total soluble metabolites, respectively. Overall, the results demonstrate the potential of using expanded clay as support material for hydrogen production in AFBRs. (author)

Elimination of Glycerol Production in Anaerobic Cultures of a Saccharomyces cerevisiae Strain Engineered To Use Acetic Acid as an Electron Acceptor

NARCIS (Netherlands)

Medina, V.G.; Almering, M.J.H.; Van Maris, A.J.A.; Pronk, J.T.

2009-01-01

In anaerobic cultures of wild-type Saccharomyces cerevisiae, glycerol production is essential to reoxidize NADH produced in biosynthetic processes. Consequently, glycerol is a major by-product during anaerobic production of ethanol by S. cerevisiae, the single largest fermentation process in

Comparison of the effectivities of two-phase and single-phase anaerobic sequencing batch reactors during dairy wastewater treatment

Energy Technology Data Exchange (ETDEWEB)

Goebloes, Sz.; Portoero, P.; Bordas, D.; Kalman, M.; Kiss, I. [Institute for Biotechnology, Bay Zoltan Foundation for Applied Research, H-6726 Szeged (Hungary)

2008-05-15

The performances of anaerobic sequencing batch reactors fed with two different substrates were studied. The substrates were raw acid whey and acid whey fermented with Kluyveromyces lactis in order to investigate the suitability of ethanol for biogas production. The organic loading rates (OLRs) during the experiment ranged from 1.6 to 12.8 g COD dm{sup -3} d{sup -1} and the corresponding decreasing hydraulic retention times from 40 to 5 days for both reactor systems. The efficiency of each system depended on the OLR: the highest COD removal rate was observed at the lowest OLR applied (about 100% in both systems), and at maximum OLR the COD removal efficiency was 68% for the reactors fed with the raw whey and 80% for those fed with the pre-fermented whey. Under the same high OLR conditions the methane yield was 0.122 dm{sup -3} CH{sub 4} g{sup -1} COD{sub degraded} for the anaerobic digesters fed with the untreated whey, and 0.197 dm{sup -3} CH{sub 4} g{sup -1} COD{sub degraded} for those fed with the pre-fermented whey. The digesters functioned without pH control. At the maximum OLR the pH in the reactors fed with the raw acid whey was 5.1, while in those fed with the pre-fermented whey it was 7.15. The results demonstrate that the use of the pre-fermented acid whey as substrate for anaerobic digestion without pH control is feasible, especially at high OLR levels. This substrate is preferable to the raw acid whey, because of the ethanol formed as a non-acidic fermentation product of the yeast. (author)

EVALUASI KARBOHIDRAT DAN LEMAK BATANG TANAMAN PISANG (Musa paradisiaca. Val HASIL FERMENTASI ANAEROB DENGAN SUPLEMENTASI NITROGEN DAN SULFUR SEBAGAI BAHAN PAKAN TERNAK

Directory of Open Access Journals (Sweden)

Tidi Dhalika

2014-06-01

Full Text Available The aim of this study was to evaluation of carbohydrate and extract ether consentration of anaerobic fermentation banana pseudostem with supplementation of nitrogen and sulfur as ruminants feed component. This study was arranged with an experimental research by Completely Randomized Design with 3 x 3 factorial. The first factor are supplementation of 0%, 1% and 2% nitrogen, and second factor are supplemetation of 0%, 0,04% and 0,08% sulphur, with 4 (four times replication. The parameter of this research is the nutrition value, i,e ; crude fiber, nitrogen free extract and extract ether concentration. The result of this research showed that not interaction between supplemetation of nitrogen and sulphur on carbohydrate and extract ether consentration of anaerobic fermentation banana pseudostem, and suplementation of 2,00% nitrogen and 0,08% sulphur give influence on decreasing of crude fiber concentration, about 14,07%, and ether extract concentration, about 54,24%, but not alteration on nitrogen free extract in anaerobic fermentation banana pseudostem.   

Methane production by anaerobic digestion of algae. Final report

Energy Technology Data Exchange (ETDEWEB)

Nyns, E.J.; Naveau, H.P.

Methane is produced experimentally by anaerobic fermentation of algae, principally of species Hydrodictyon and Cladophora, grown in cooling water from nuclear power plants. The accumulation of fatty acids, by-products of fermentation, is found to have an inhibitory effect on methane production. Methods to remove fatty acids and stabilise the reaction are investigated. An economic analysis is presented using a financial model processor based on data from experimental digesters. The experimental work is described and the results are presented in an Appendix (in French). Seven relevant papers, of which two are in French are also annexed.

Solid-phase fermentation and juice expression systems for sweet sorghum

Energy Technology Data Exchange (ETDEWEB)

Bryan, W.L.; Monroe, G.E.; Caussariel, P.M.

1985-01-01

Two systems to recover fermented juice from variety M 81E sweet sorghum stalks that contained about 11% fermentable sugar were compared. (a) Stalks with leaves and tops removed were chopped and inoculated with 0.2% yeast in a forage harvester, stored under anaerobic conditions for 75 hours in insulated fermentors and pressed in a screw press to recover fermented juice (5-6% ethanol). (b) Mechanically harvested sweet sorghum billets (30 cm length) without leaves or seed heads were shredded and milled in a 3-roll mill; and bagasse was inoculated with 0.2% yeast, fermented for 100 h and pressed to recover fermented juice (4 to 5% ethanol). Potential ethanol yields were 75% of theoretical for the forage harvest system and 78% for the shredder mill system, based on 95% of theoretical ethanol yield from juice expressed during milling and no loss of ethanol during fermentation, handling and pressing in the screw press. 20 references.

Changes in biochemical constituent of some organic waste materials under anaerobic methane fermentation

Energy Technology Data Exchange (ETDEWEB)

Prasad, C R; Gulati, K C; Idnani, M A

1970-10-01

Changes in the percentage composition of holocellulose, cellulose, hemicellulose, lignin, pentosans and methoxyl contents of organic materials after fermentation of various systems like cow dung alone, cowdung-gum arabic, cowdung-wheat straw, cowdung-groundnut shells and cowdung-sugarcane bagasse by methane organisms indicated that the systems which had holocellulose (lignin in a ratio of 3 : 1 or less before fermentation) showed a greater decrease of hemicellulose fraction than of cellulose fraction. The percentage of lignin (18.41-22.03) and pentosans (0.292-5.129) increased after fermentation, except in cowdung-gum arabic which showed decrease of pentosans content. Methoxyl contents also decreased after fermentation, indicating a positive role of methyl group of methoxyls in the formation of methane by methane formers.

Construction of lactose-consuming Saccharomyces cerevisiae for lactose fermentation into ethanol fuel.

Science.gov (United States)

Zou, Jing; Guo, Xuewu; Shen, Tong; Dong, Jian; Zhang, Cuiying; Xiao, Dongguang

2013-04-01

Two lactose-consuming diploid Saccharomyces cerevisiae strains, AY-51024A and AY-51024M, were constructed by expressing the LAC4 and LAC12 genes of Kluyveromyces marxianus in the host strain AY-5. In AY-51024A, both genes were targeted to the ATH1 and NTH1 gene-encoding regions to abolish the activity of acid/neutral trehalase. In AY-51024M, both genes were respectively integrated into the MIG1 and NTH1 gene-encoding regions to relieve glucose repression. Physiologic studies of the two transformants under anaerobic cultivations in glucose and galactose media indicated that the expression of both LAC genes did not physiologically burden the cells, except for AY-51024A in glucose medium. Galactose consumption was initiated at higher glucose concentrations in the MIG1 deletion strain AY-51024M than in the corresponding wild-type strain and AY-51024A, wherein galactose was consumed until glucose was completely depleted in the mixture. In lactose medium, the Sp. growth rates of AY-51024A and AY-51024M under anaerobic shake-flasks were 0.025 and 0.067 h(-1), respectively. The specific lactose uptake rate and ethanol production of AY-51024M were 2.50 g lactose g CDW(-1) h(-1) and 23.4 g l(-1), respectively, whereas those of AY-51024A were 0.98 g lactose g CDW(-1) h(-1) and 24.3 g lactose g CDW(-1) h(-1), respectively. In concentrated cheese whey powder solutions, AY-51024M produced 63.3 g l(-1) ethanol from approximately 150 g l(-1) initial lactose in 120 h, conversely, AY-51024A consumed 63.7 % of the initial lactose and produced 35.9 g l(-1) ethanol. Therefore, relieving glucose repression is an effective strategy for constructing lactose-consuming S. cerevisiae.

An anaerobic bioreactor system for biobutanol production

Energy Technology Data Exchange (ETDEWEB)

Paekkilae, J.; Hillukkala, T.; Myllykoski, L.; Keiski, R.L. (Univ. of Oulu, Dept. of Process and Environmental Engineering (Finland)). email: johanna.pakkila@oulu.fi

2009-07-01

Concerns about the greenhouse effect, as well as legislation to reduce CO{sub 2} emissions and to increase the use of renewable energy have been the main reasons for the increased production and use of biofuels. In addition to bioethanol and biodiesel production, the research on biobutanol production has also increased during the past years. Butanol can be produced by chemical or biochemical routes. Fuel properties of butanol are considered to be superior to ethanol because of higher energy content, and better air-to-fuel ratio. Butanol is also less volatile and explosive than ethanol, has higher flash point and lower vapour pressure which makes it safer to handle. Biobutanol production is an anaerobic two-stage fermentation process where acetic and butyric acids, carbon dioxide and hydrogen are first produced in the acidogenic phase. Then the culture undergoes metabolic shift to solventogenic phase and acids are converted into acetone, ethanol and butanol. At the end of the fermentation, products are recovered from the cell mass, other suspended solids, and by-products. Several species of Clostridium bacteria are capable to metabolize different sugars, amino and organic acids, polyalcohols and other organic compounds to butanol and other solvents. Feedstock materials for biobutanol are diverse, including different kind of by-products, wastes and residues of agriculture and industry. Optimal fermentation conditions (pH, temperature, nutrients), products and their ratio vary with strains and substrates used. Biobutanol production has still some limitations including butanol toxicity to culture leading to low butanol yields. The product inhibition hinders the yield of butanol and acids, making integrated product separation process highly favorable. Butanol recovery from fermentation broth is expensive because of the low butanol concentration and high boiling point (118 degC). Several different recovery methods are available. Membrane-based methods such as membrane

Modeling of acetate-type fermentation of sugar-containing wastewater under acidic pH conditions.

Science.gov (United States)

Huang, Liang; Pan, Xin-Rong; Wang, Ya-Zhou; Li, Chen-Xuan; Chen, Chang-Bin; Zhao, Quan-Bao; Mu, Yang; Yu, Han-Qing; Li, Wen-Wei

2018-01-01

In this study, a kinetic model was developed based on Anaerobic Digestion Model No. 1 to provide insights into the directed production of acetate and methane from sugar-containing wastewater under low pH conditions. The model sufficiently described the dynamics of liquid-phase and gaseous products in an anaerobic membrane bioreactor by comprehensively considering the syntrophic bioconversion steps of sucrose hydrolysis, acidogenesis, acetogenesis and methanogenesis under acidic pH conditions. The modeling results revealed a significant pH-dependency of hydrogenotrophic methanogenesis and ethanol-producing processes that govern the sucrose fermentative pathway through changing the hydrogen yield. The reaction thermodynamics of such acetate-type fermentation were evaluated, and the implications for process optimization by adjusting the hydraulic retention time were discussed. This work sheds light on the acid-stimulated acetate-type fermentation process and may lay a foundation for optimization of resource-oriented processes for treatment of food wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

A field experiment for the anaerobic biotransformation of aromatic hydrocarbon compounds at Seal Beach, California

International Nuclear Information System (INIS)

Reinhard, M.; Wills, L.E.; Ball, H.A.; Harmon, T.

1991-01-01

Biotransformation of aromatic hydrocarbons under anaerobic conditions is of interest because dissolved oxygen is rapidly consumed in groundwater contaminant plumes of hydrocarbon fuel. Anaerobic biotransformation of aromatic hydrocarbons has been demonstrated under different redox regimes including nitrate-reducing iron-reducing and fermentative-methanogenic conditions. Recently, laboratory evidence has been obtained for the degradation of alkylbenzenes including toluene under sulfate-reducing conditions. The long-term objective of this study is to determine transformation rates under the conditions of the Seal Beach site, and second to explore the feasibility of inducing nitrate- and sulfate-reducing conditions and fermentative-methanogenic conditions in field bioreactors. Both laboratory studies and field studies in bioreactors are being conducted. This paper reports on the experimental design of the bioreactors and initial results

Anaerobic detoxification fermentation by Rhodospirillum rubrum for rice straw as feed with moderate pretreatment.

Science.gov (United States)

Zhang, Jian; Yuan, Jie; Zhang, Wen-Xue; Tu, Fang; Jiang, Ya; Sun, Chuan-Ze

2018-01-02

A novel and effective process was put forward for converting rice straw into feed by combining diluted acid hydrolysis and ammonization with Rhodospirillum rubrum fermentation. After pretreatment with dilute sulfuric or phosphoric acid (1%, w/w) at 100°C, materials were subjected to fermentation under several gases (N 2 , CO 2 , and air) and different light intensities in a 2-L fermentor. The key indexes of feed for fermented materials were estimated and several toxic substances were investigated during the fermentation. Following sulfuric acid treatment, the true protein of rice straw increased from 29 to 143 g kg -1 and the crude fiber decreased from 359 to 136 g kg -1 after fermentation at 0.3 L min -1  L -1 of N 2 flow and a light intensity of 3400 lux; and following phosphoric acid treatment, the true protein increased by 286% and the crude fiber decreased by 52% after fermentation at 0.4 L min -1  L -1 of N 2 flow and a light intensity of 3000 lux. Other key contents were also improved for use as feed, and some toxic substances (i.e., furfural, hydroxymethylfurfural, acetic acid, phenol, cresol) produced by the pretreatments could be removed at low levels during the fermentations.

D-Galactose uptake is nonfunctional in the conidiospores of Aspergillus niger

NARCIS (Netherlands)

Fekete, E.; de Vries, R.P.; Seiboth, B.; vanKuyk, P.A.; Sandor, E.; Metz, B.; Kubicek, C.P.; Karaffa, L.

2012-01-01

The majority of black Aspergilli (Aspergillus section Nigri), including Aspergillus niger, as well as many other Ascomycetes fail to germinate on d-galactose as a sole carbon source. Here, we provide evidence that the ability of A. niger to transport d-galactose is growth stage dependent, being

Enhancement of Antioxidative and Intestinal Anti-inflammatory Activities of Glycated Milk Casein after Fermentation with Lactobacillus rhamnosus 4B15.

Science.gov (United States)

Oh, Nam Su; Joung, Jae Yeon; Lee, Ji Young; Kim, Younghoon; Kim, Sae Hun

2017-06-14

In this study, we investigated the glycoproteomics of glycated milk casein (GMC) and GMC fermented by Lactobacillus rhamnosus 4B15 (FGMC) and determined their biological implications. There was a significant increase in the antioxidative and anti-inflammatory activities of GMC with galactose, which were higher than those of GMC with glucose (GMC-glc). Furthermore, the fermentation of GMC by L. rhamnosus 4B15 synergistically enhanced the above activities compared to those of unfermented GMC. Especially, fermented GMC-glc (FGMC-glc) possessed remarkably improved reducing power and radical scavenging activities. Moreover, FGMC-glc ameliorated the inflammatory response and tight junction-related intestinal epithelial dysfunction. Additionally, hexose-derived glycation and modification sites in protein sequences of GMC were identified. In particular, glycosylation and sulfation of serine and threonine residues were observed, and distinct modification sites were detected after fermentation. Therefore, these results indicated that glycation-induced modification of casein and fermentation correlated strongly with the enhanced functional properties.

Effect of curcumin on galactose-induced cataractogenesis in rats.

Science.gov (United States)

Suryanarayana, Palla; Krishnaswamy, Kamala; Reddy, Geereddy Bhanuprakash

2003-06-09

Curcumin, the active principle of turmeric, has been shown to have both antioxidant and hypoglycemic activity in vitro and in vivo. The purpose of this study was to investigate the effect of curcumin on the onset and maturation of galactose induced cataract. Sprague-Dawley rats (21 days old) were divided into 5 groups. The control group (A) received an AIN-93 diet, the galactose group (B) received 30% galactose in the diet, the test groups (C and D) received the B group diet plus 0.002% and 0.01% curcumin respectively, and group (E) received the control diet plus 0.01% curcumin, all for a period of 4 weeks. Cataract progression due to galactose feeding was monitored by slit lamp microscope and classified into 4 stages. At the end of the experiment biochemical parameters such as lipid peroxidation, aldose reductase (AR), sorbitol dehydrogenase (SDH), reduced glutathione, protein content, and protein carbonyls were measured in the lens. Advanced glycated end products (AGE) and protein oxidation were measured by AGE and tryptophon fluorescence respectively. Crystallin profile was analyzed by size exclusion chromatography (HPLC). Slit lamp microscope observations indicated that curcumin at 0.002% (group C) delayed the onset and maturation of cataract. In contrast even though there was a slight delay in the onset of cataract at the 0.01% level (group D), maturation of cataract was faster when compared to group B. Biochemical analysis showed that curcumin at the 0.002% level appeared to exert antioxidant and antiglycating effects, as it inhibited lipid peroxidation, AGE-fluorescence, and protein aggregation. Though the reasons for faster onset and maturation of cataract in group D rats was not clear, the data suggested that under hyperglycemic conditions higher levels of curcumin (0.01%) in the diet may increase oxidative stress, AGE formation, and protein aggregation. However, feeding of curcumin to normal rats up to a 0.01% level did not result in any changes in lens

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...

In vivo dynamics of galactose metabolism in Saccharomyces cerevisiae: Metabolic fluxes and metabolite levels

DEFF Research Database (Denmark)

Østergaard, Simon; Olsson, Lisbeth; Nielsen, Jens

2001-01-01

The dynamics of galactose metabolism in Saccharomyces cerevisiae was studied by analyzing the metabolic response of the CEN.PK 113-7D wild-type strain when exposed to a galactose pulse during aerobic growth in a galactose-limited steady-state cultivation at a dilution rate of 0.097 h(-1). A fast...

Effect of some environmental parameters on fermentative hydrogen production by Enterobacter cloacae DM11

Energy Technology Data Exchange (ETDEWEB)

Nath, K.; Kumar, A.; Das, D. [Indian Inst. of Technology, Kharagpur (India). Dept. of Biotechnology, Fermentation Technology Laboratory

2006-06-15

This study addressed the issue of using biological systems for hydrogen production as an environmentally sound alternative to conventional thermochemical and electrochemical processes. In particular, it examined the potential for anaerobic fermentation for biological hydrogen production and the possibility of coupling gaseous energy generation with simultaneous treatment of biodegradable waste materials. The study focused on hydrogen production by anaerobic fermentation using Enterobacter cloacae DM11, a Gram-negative, motile facultative anaerobe. Although hydrogen production by these bacteria depends on many environmental parameters, there is very little information on the effects of these factors in the hydrogen production potential of this organism. For that reason, this study examined the effect of initial medium pH, reaction temperature, initial glucose concentration, and iron (Fe2+) concentration on the fermentative production of hydrogen. Fermentative hydrogen production was carried out by Enterobacter cloacae DM11, using glucose as the substrate. Batch cultivations were performed in a 500 ml custom-designed vertical tubular bioreactor. The maximum molar yield of hydrogen was 3.31 mol (mol glucose){sub 1}. The rate and cumulative volume of hydrogen production decreased at higher initial glucose concentration. The pH of 6.5 at a temperature of 37 degrees C was most suitable for maximum rate of production of hydrogen in batch fermentation. The addition of Fe2+ on hydrogen production had a marginal enhancing effect on total hydrogen production. A simple model developed from the modified Gompertz equation was used to fit the cumulative hydrogen production curve and to estimate the hydrogen production potential, maximum production rate, and lag time. It was concluded that these study results could be used in the development of a high rate continuous hydrogen production process. 30 refs., 4 tabs., 3 figs.

Genome-centric metatranscriptomes and ecological roles of the active microbial populations during cellulosic biomass anaerobic digestion.

Science.gov (United States)

Jia, Yangyang; Ng, Siu-Kin; Lu, Hongyuan; Cai, Mingwei; Lee, Patrick K H

2018-01-01

Although anaerobic digestion for biogas production is used worldwide in treatment processes to recover energy from carbon-rich waste such as cellulosic biomass, the activities and interactions among the microbial populations that perform anaerobic digestion deserve further investigations, especially at the population genome level. To understand the cellulosic biomass-degrading potentials in two full-scale digesters, this study examined five methanogenic enrichment cultures derived from the digesters that anaerobically digested cellulose or xylan for more than 2 years under 35 or 55 °C conditions. Metagenomics and metatranscriptomics were used to capture the active microbial populations in each enrichment culture and reconstruct their meta-metabolic network and ecological roles. 107 population genomes were reconstructed from the five enrichment cultures using a differential coverage binning approach, of which only a subset was highly transcribed in the metatranscriptomes. Phylogenetic and functional convergence of communities by enrichment condition and phase of fermentation was observed for the highly transcribed populations in the metatranscriptomes. In the 35 °C cultures grown on cellulose, Clostridium cellulolyticum -related and Ruminococcus -related bacteria were identified as major hydrolyzers and primary fermenters in the early growth phase, while Clostridium leptum -related bacteria were major secondary fermenters and potential fatty acid scavengers in the late growth phase. While the meta-metabolism and trophic roles of the cultures were similar, the bacterial populations performing each function were distinct between the enrichment conditions. Overall, a population genome-centric view of the meta-metabolism and functional roles of key active players in anaerobic digestion of cellulosic biomass was obtained. This study represents a major step forward towards understanding the microbial functions and interactions at population genome level during the

Optimization of culture conditions for gamma-aminobutyric acid production in fermented adzuki bean milk

Directory of Open Access Journals (Sweden)

Hung Yi Song

2018-01-01

Full Text Available γ-Aminobutyric acid (GABA, a nonprotein amino acid, is widely distributed in nature and fulfills several physiological functions. In this study, various lactic acid strains commonly used to produce fermented milk products were inoculated into adzuki bean milk for producing GABA. The high GABA producing strain was selected in further experiment to improve the GABA production utilizing culture medium optimization. The results demonstrated that adzuki bean milk inoculated with Lactobacillus rhamnosus GG increased GABA content from 0.05 mg/mL to 0.44 mg/mL after 36 hours of fermentation, which showed the greatest elevation in this study. Furthermore, the optimal cultural condition to adzuki bean milk inoculated with L. rhamnosus GG to improve the GABA content was performed using response surface methodology. The results showed that GABA content was dependent on the addition of galactose, monosodium glutamate, and pyridoxine with which the increasing ratios of GABA were 23–38%, 24–68%, and 8–36%, respectively. The optimal culture condition for GABA production of adzuki bean milk was found at the content of 1.44% galactose, 2.27% monosodium glutamate, and 0.20% pyridoxine. Under the optimal cultural condition, the amount of GABA produced in the fermented adzuki bean milk was 1.12 mg/mL, which was 22.4-fold higher than that of the unfermented adzuki bean milk (0.05 mg/100 mL. The results suggested that the optimized cultural condition of adzuki bean milk inoculated with L. rhamnosus GG can increase GABA content for consumers as a daily supplement as suggested.

Anaerobic accumulation of short-chain fatty acids from algae enhanced by damaging cell structure and promoting hydrolase activity.

Science.gov (United States)

Feng, Leiyu; Chen, Yunzhi; Chen, Xutao; Duan, Xu; Xie, Jing; Chen, Yinguang

2018-02-01

Short-chain fatty acid (SCFAs) produced from harvested algae by anaerobic fermentation with uncontrolled pH was limited due to the solid cell structure of algae. This study, therefore, was undertaken to enhance the generation of SCFAs from algae by controlling the fermentation pH. pH influenced not only the total SCFAs production, but the percentage of individual SCFA. The maximal yield of SCFAs occurred at pH 10.0 and fermentation time of 6 d (3161 mg COD/L), which mainly contained acetic and iso-valeric acids and was nearly eight times that at uncontrolled pH (392 mg COD/L). Mechanism exploration revealed at alkaline pH, especially at pH 10.0, not only the cell structure of algae was damaged effectively, but also activities and relative quantification of hydrolases as well as the abundance of microorganisms responsible for organics hydrolysis and SCFAs production were improved. Also, the released microcystins from algae were removed efficiently during alkaline anaerobic fermentation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biological fermentative hydrogen production from olive pulp at 35 degrees C

Energy Technology Data Exchange (ETDEWEB)

Koutrouli, E.C.; Gavala, H.N.; Skiadas, I.V.; Lyberatos, G. [Patras Univ., Patras (Greece). Dept. of Chemical Engineering

2004-07-01

In response to energy security and environmental concerns, there is renewed interest in the use of hydrogen gas as a renewable energy source. However, many processes for generating hydrogen are extremely energy intensive and costly. This study focused on biological production of hydrogen from wastewater or other biomass. Photosynthetic and fermentation processes were outlined, but the main focus of this paper was on continuous anaerobic fermentation of low cost substrates such as olive pulp at 35 degrees C. This process is linked to the acidogenic stage of anaerobic digestion where carbohydrates are the preferred carbon source. Volatile fatty acids and alcohols are produced simultaneously with the hydrogen gas. An added advantage is that the effluent from the fermentation process can be further used by methanogenesis due to its rich organic acids content. Batch experiments with olive pulp resulted in 2.5 mmole of hydrogen per gram of total carbohydrates. It was noted that more research is required to maximize hydrogen production in a continuous process. It was suggested that hydrogen production could be optimized through hydrolysis of the non-soluble carbohydrates. This could be accomplished through physicochemical or biological pretreatments. 7 refs., 3 tabs., 1 fig.

Direction of glucose fermentation towards hydrogen or ethanol production through on-line pH control

Energy Technology Data Exchange (ETDEWEB)

Karadag, Dogan; Puhakka, Jaakko A. [Department of Chemistry and Bioengineering, Tampere University of Technology, Tampere (Finland)

2010-10-15

The present study investigated the production of hydrogen (H{sub 2}) and ethanol from glucose in an Anaerobic Continuous Stirred Tank Reactor (ACSTR). Effects of hydraulic retention time (HRT) and pH on the preference of producing H{sub 2} and/or ethanol and other soluble metabolic products in an open anaerobic enriched culture were studied. Production rates of H{sub 2} and ethanol increased with the increase of biomass concentration. Open anaerobic fermentation was directed and managed through on-line pH control for the production of H{sub 2} or ethanol. Hydrogen was produced by ethanol and acetate-butyrate type fermentations. pH has strong effect on the H{sub 2} or ethanol production by changing fermentation pathways. ACSTR produced mainly ethanol at over pH 5.5 whereas highest H{sub 2} production was obtained at pH 5.0. pH 4.9 favored the lactate production and accumulation of lactate inhibited the biomass concentration in the reactor and the production of H{sub 2} and ethanol. The microbial community structure quickly responded to pH changes and the Clostridia dominated in ACSTR during the study. H{sub 2} production was maintained mainly by Clostridium butyricum whereas in the presence of Bacillus coagulans glucose oxidation was directed to lactate production. (author)

Aerobic Stability and Effects of Yeasts during Deterioration of Non-fermented and Fermented Total Mixed Ration with Different Moisture Levels

Directory of Open Access Journals (Sweden)

W. Hao

2015-06-01

Full Text Available The present experiment evaluated the influence of moisture level and anaerobic fermentation on aerobic stability of total mixed ration (TMR. The dynamic changes in chemical composition and microbial population that occur after air exposure were examined, and the species of yeast associated with the deterioration process were also identified in both non-fermented and fermented TMR to deepen the understanding of aerobic deterioration. The moisture levels of TMR in this experiment were adjusted to 400 g/kg (low moisture level, LML, 450 g/kg (medium moisture level, MML, and 500 g/kg (high moisture level, HML, and both non-fermented and 56-d-fermented TMR were subjected to air exposure to determine aerobic stability. Aerobic deterioration resulted in high losses of nutritional components and largely reduced dry matter digestibility. Non-fermented TMR deteriorated during 48 h of air exposure and the HML treatment was more aerobically unstable. On dry matter (DM basis, yeast populations significantly increased from 107 to 1010 cfu/g during air exposure, and Candida ethanolica was the predominant species during deterioration in non-fermented TMR. Fermented TMR exhibited considerable resistance to aerobic deterioration. Spoilage was only observed in the HML treatment and its yeast population increased dramatically to 109 cfu/g DM when air exposure progressed to 30 d. Zygosaccharomyces bailii was the sole yeast species isolated when spoilage occurred. These results confirmed that non-fermented and fermented TMR with a HML are more prone to spoilage, and fermented TMR has considerable resistance to aerobic deterioration. Yeasts can trigger aerobic deterioration in both non-fermented and fermented TMR. C. ethanolica may be involved in the spoilage of non-fermented TMR and the vigorous growth of Z. bailii can initiate aerobic deterioration in fermented TMR.

Aerobic Stability and Effects of Yeasts during Deterioration of Non-fermented and Fermented Total Mixed Ration with Different Moisture Levels.

Science.gov (United States)

Hao, W; Wang, H L; Ning, T T; Yang, F Y; Xu, C C

2015-06-01

The present experiment evaluated the influence of moisture level and anaerobic fermentation on aerobic stability of total mixed ration (TMR). The dynamic changes in chemical composition and microbial population that occur after air exposure were examined, and the species of yeast associated with the deterioration process were also identified in both non-fermented and fermented TMR to deepen the understanding of aerobic deterioration. The moisture levels of TMR in this experiment were adjusted to 400 g/kg (low moisture level, LML), 450 g/kg (medium moisture level, MML), and 500 g/kg (high moisture level, HML), and both non-fermented and 56-d-fermented TMR were subjected to air exposure to determine aerobic stability. Aerobic deterioration resulted in high losses of nutritional components and largely reduced dry matter digestibility. Non-fermented TMR deteriorated during 48 h of air exposure and the HML treatment was more aerobically unstable. On dry matter (DM) basis, yeast populations significantly increased from 10(7) to 10(10) cfu/g during air exposure, and Candida ethanolica was the predominant species during deterioration in non-fermented TMR. Fermented TMR exhibited considerable resistance to aerobic deterioration. Spoilage was only observed in the HML treatment and its yeast population increased dramatically to 10(9) cfu/g DM when air exposure progressed to 30 d. Zygosaccharomyces bailii was the sole yeast species isolated when spoilage occurred. These results confirmed that non-fermented and fermented TMR with a HML are more prone to spoilage, and fermented TMR has considerable resistance to aerobic deterioration. Yeasts can trigger aerobic deterioration in both non-fermented and fermented TMR. C. ethanolica may be involved in the spoilage of non-fermented TMR and the vigorous growth of Z. bailii can initiate aerobic deterioration in fermented TMR.

Effects of bacterial inoculation on the fermentation characteristics ...

African Journals Online (AJOL)

The effect of bacterial inoculation on the fermentation and aerobic stability of two ensiled whole plant soybean (WPSB) cultivars was determined in a 2 x 2 factorial design. Two WPSB cultivars, Link LF6466 and Pannar 522 RR, were harvested at their R6 growth stage, chopped to 25 mm and ensiled in 1.5 L anaerobic jars.

Optimization of Anaerobic Digestion of Cattle Manure. Effect of its Association with the Aquatic Weed Pistia (Pistia stratiotes

Directory of Open Access Journals (Sweden)

Zennaki, Z.

1997-01-01

Full Text Available This study investigates the improvement of performance of anaerobic fermentation of cattle manure mixed with the water lettuce Pistia stratiotes, a macrophyte plant growing in the effluent of an anaerobic digestor. The experiments used a series of continuous fermentors, using mixtures of cattle manure and water lettuce in the following proportions : 12.5 %, 16.6 %, 25 % and 50 % of Pistia stratiotes. The best biogas yields were achieved with a proportion of 50 % of water lettuce in the mixture giving a biogas yield of 0.62 m3/(m3. d. with a methane content of 76.8 % over a 15-days hydraulic retention time, at a constant temperature of 35° C. The kinetic study based on batch fermentation shows that the process is well represented by the Monod Model. These performances are better than those obtained in anaerobic digestion of cattle manure used alone.

Comparison of solid-state and submerged-state fermentation for the bioprocessing of switchgrass to ethanol and acetate by Clostridium phytofermentans.

Science.gov (United States)

Jain, Abhiney; Morlok, Charles K; Henson, J Michael

2013-01-01

The conversion of sustainable energy crops using microbiological fermentation to biofuels and bioproducts typically uses submerged-state processes. Alternatively, solid-state fermentation processes have several advantages when compared to the typical submerged-state processes. This study compares the use of solid-state versus submerged-state fermentation using the mesophilic anaerobic bacterium Clostridium phytofermentans in the conversion of switchgrass to the end products of ethanol, acetate, and hydrogen. A shift in the ratio of metabolic products towards more acetate and hydrogen production than ethanol production was observed when C. phytofermentans was grown under solid-state conditions as compared to submerged-state conditions. Results indicated that the end product concentrations (in millimolar) obtained using solid-state fermentation were higher than using submerged-state fermentation. In contrast, the total fermentation products (in weight of product per weight of carbohydrates consumed) and switchgrass conversion were higher for submerged-state fermentation. The conversion of xylan was greater than glucan conversion under both fermentation conditions. An initial pH of 7 and moisture content of 80 % resulted in maximum end products formation. Scanning electron microscopy study showed the presence of biofilm formed by C. phytofermentans growing on switchgrass under submerged-state fermentation whereas bacterial cells attached to surface and no apparent biofilm was observed when grown under solid-state fermentation. To our knowledge, this is the first study reporting consolidated bioprocessing of a lignocellulosic substrate by a mesophilic anaerobic bacterium under solid-state fermentation conditions.

Electrochemical biosensing of galactose based on carbon materials: graphene versus multi-walled carbon nanotubes.

Science.gov (United States)

Dalkıran, Berna; Erden, Pınar Esra; Kılıç, Esma

2016-06-01

In this study, two enzyme electrodes based on graphene (GR), Co3O4 nanoparticles and chitosan (CS) or multi-walled carbon nanotubes (MWCNTs), Co3O4 nanoparticles, and CS, were fabricated as novel biosensing platforms for galactose determination, and their performances were compared. Galactose oxidase (GaOx) was immobilized onto the electrode surfaces by crosslinking with glutaraldehyde. Optimum working conditions of the biosensors were investigated and the analytical performance of the biosensors was compared with respect to detection limit, linearity, repeatability, and stability. The MWCNTs-based galactose biosensor provided about 1.6-fold higher sensitivity than its graphene counterpart. Moreover, the linear working range and detection limit of the MWCNTs-based galactose biosensor was superior to the graphene-modified biosensor. The successful application of the purposed biosensors for galactose biosensing in human serum samples was also investigated.

In-Situ Anaerobic Biosurfactant Production Process For Remediation Of DNAPL Contamination In Subsurface Aquifers

Science.gov (United States)

Albino, J. D.; Nambi, I. M.

2009-12-01

Microbial Enhanced Oil Recovery (MEOR) and remediation of aquifers contaminated with hydrophobic contaminants require insitu production of biosurfactants for mobilization of entrapped hydrophobic liquids. Most of the biosurfactant producing microorganisms produce them under aerobic condition and hence surfactant production is limited in subsurface condition due to lack of oxygen. Currently bioremediation involves expensive air sparging or excavation followed by exsitu biodegradation. Use of microorganisms which can produce biosurfactants under anaerobic conditions can cost effectively expedite the process of insitu bioremediation or mobilization. In this work, the feasibility of anaerobic biosurfactant production in three mixed anaerobic cultures prepared from groundwater and soil contaminated with chlorinated compounds and municipal sewage sludge was investigated. The cultures were previously enriched under complete anaerobic conditions in the presence of Tetrachloroethylene (PCE) for more than a year before they were studied for biosurfactant production. Biosurfactant production under anaerobic conditions was simulated using two methods: i) induction of starvation in the microbial cultures and ii) addition of complex fermentable substrates. Positive result for biosurfactant production was not observed when the cultures were induced with starvation by adding PCE as blobs which served as the only terminal electron acceptor. However, slight reduction in interfacial tension was noticed which was caused by the adherence of microbes to water-PCE interface. Biosurfactant production was observed in all the three cultures when they were fed with complex fermentable substrates and surface tension of the liquid medium was lowered below 35 mN/m. Among the fermentable substrates tested, vegetable oil yielded highest amount of biosurfactant in all the cultures. Complete biodegradation of PCE to ethylene at a faster rate was also observed when vegetable oil was amended to the

D-galactose-induced brain ageing model

DEFF Research Database (Denmark)

Sadigh-Eteghad, Saeed; Majdi, Alireza; McCann, Sarah K.

2017-01-01

Animal models are commonly used in brain ageing research. Amongst these, models where rodents are exposed to d-galactose are held to recapitulate a number of features of ageing including neurobehavioral and neurochemical changes. However, results from animal studies are often inconsistent...

IgG N-glycans as potential biomarkers for determining galactose tolerance in Classical Galactosaemia.

LENUS (Irish Health Repository)

Coss, K P

2012-02-01

N-glycan processing and assembly defects have been demonstrated in untreated and partially treated patients with Classical Galactosaemia. These defects may contribute to the ongoing pathophysiology of this disease. The aim of this study was to develop an informative method of studying differential galactose tolerance levels and diet control in individuals with Galactosaemia, compared to the standard biochemical markers. Ten Galactosaemia adults with normal intellectual outcomes were analyzed in the study. Five subjects followed galactose liberalization, increments of 300 mg to 4000 mg\\/day over 16 weeks, and were compared to five adult Galactosaemia controls on a galactose restricted diet. All study subjects underwent clinical and biochemical monitoring of red blood cell galactose-1-phosphate (RBC Gal-1-P) and urinary galactitol levels. Serum N-glycans were isolated and analyzed by normal phase high-performance liquid chromatography (NP-HPLC) with galactosylation of IgG used as a specific biomarker of galactose tolerance. IgG N-glycan profiles showed consistent individual alterations in response to diet liberalization. The individual profiles were improved for all, but one study subject, at a galactose intake of 1000 mg\\/day, with decreases in agalactosylated (G0) and increases in digalactosylated (G2) N-glycans. We conclude that IgG N-glycan profiling is an improved method of monitoring variable galactosylation and determining individual galactose tolerance in Galactosaemia compared to the standard methods.

Two galactose-α-1,3-galactose carrying peptidases from pork kidney mediate anaphylactogenic responses in delayed meat allergy

DEFF Research Database (Denmark)

Hilger, Christiane; Fischer, Jörg; Swiontek, Kyra

2016-01-01

BACKGROUND: Serum IgE-antibodies directed at galactose-α-1,3-galactose (α-Gal) are associated with a novel form of delayed anaphylaxis occuring upon consumption of red meat or innards. Pork kidney is known as the most potent trigger of this syndrome, but the culprit allergens have not yet been...... resistent to heat denaturation. Pork kidney extract, isolated ACE I and AP-N were able to activate patient basophils and elicit positive responses in skin prick tests. CONCLUSION: Two cell-membrane proteins carrying α-Gal epitopes were identified in pork kidney. For the first time, isolated meat proteins...... were shown to induce basophil activation in patients with delayed anaphylaxis to red meat providing further confirmation for the clinical relevance of these α-Gal-carrying proteins. This article is protected by copyright. All rights reserved....

Inhibitors degradation and microbial response during continuous anaerobic conversion of hydrothermal liquefaction wastewater.

Science.gov (United States)

Si, Buchun; Li, Jiaming; Zhu, Zhangbing; Shen, Mengmeng; Lu, Jianwen; Duan, Na; Zhang, Yuanhui; Liao, Qiang; Huang, Yun; Liu, Zhidan

2018-07-15

One critical challenge of hydrothermal liquefaction (HTL) is its complex aqueous product, which has a high concentration of organic pollutants (up to 100gCOD/L) and diverse fermentation inhibitors, such as furfural, phenolics and N-heterocyclic compounds. Here we report continuous anaerobic digestion of HTL wastewater via an up-flow anaerobic sludge bed reactor (UASB) and packed bed reactor (PBR). Specifically, we investigated the transformation of fermentation inhibitors and microbial response. GC-MS identified the complete degradation of furfural and 5-hydroxymethylfurfural (5-HMF), and partial degradation (54.0-74.6%) of organic nitrogen and phenolic compounds, including 3-hydroxypyridine, phenol and 4-ethyl-phenol. Illumina MiSeq sequencing revealed that the bacteria families related to detoxification increased in response to the HTL aqueous phase. In addition, the increase of acetate-oxidizing bacteria in UASB and acetogens in PBR showed a strengthened acetogenesis. As for the archaeal communities, an increase in hydrogenotrophic methanogens was observed. Based on GC-MS/HPLC and microbial analysis, we speculate that dominant fermentation inhibitors were transformed into intermediates (Acetyl-CoA and acetate), further contributing to biomethane formation. Copyright © 2018 Elsevier B.V. All rights reserved.

Fermentation of mucins and plant polysaccharides by anaerobic bacteria from the human colon.

Science.gov (United States)

Salyers, A A; West, S E; Vercellotti, J R; Wilkins, T D

1977-01-01

A total of 154 strains from 22 species of Bifidobacterium, Peptostreptococcus, Lactobacillus, Ruminococcus, Coprococcus, Eubacterium, and Fusobacterium, which are present in high concentrations in the human colon, were surveyed for their ability to ferment 21 different complex carbohydrates. Plant polysaccharides, including amylose, amylopectin, pectin, polygalacturonate, xylan, laminarin, guar gum, locust bean gum, gum ghatti, gum arabic, and gum tragacanth, were fermented by some strains from Bifidobacterium, Peptostreptococcus, Ruminococcus, and Eubacterium species. Porcine gastric mucin, which was fermented by some strains of Ruminococcus torques and Bifidobacterium bifidum, was the only mucin utilized by any of the strains tested. PMID:563214

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.

In situ Removal of Hydrogen Sulfide During Biogas Fermentation at Microaerobic Condition.

Science.gov (United States)

Wu, Mengmeng; Zhang, Yima; Ye, Yuanyuan; Lin, Chunmian

2016-11-01

In this paper, rice straw was used as a raw material to produce biogas by anaerobic batch fermentation at 35 °C (mesophilic) or 55 °C (thermophilic). The hydrogen sulfide in biogas can be converted to S 0 or sulfate and removed in-situ under micro-oxygen environment. Trace oxygen was conducted to the anaerobic fermentation tank in amount of 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, or 10.0 times stoichiometric equivalence, respectively, and the control experiment without oxygen addition was carried out. The results showed that the initial H 2 S concentrations of biogas are about 3235 ± 185 mg/m 3 (mesophilic) or 3394 ± 126 mg/m 3 (thermophilic), respectively. The desulfurization efficiency is 72.3 % (mesophilic) or 65.6 % (thermophilic), respectively, with oxygen addition by stoichiometric relation. When the oxygen feeded in amount of 2∼4 times, theoretical quantity demanded the removal efficiency of hydrogen sulfide could be over 92 %, and the oxygen residue in biogas could be maintained less than 0.5 %, which fit the requirement of biogas used as vehicle fuel or combined to the grid. Though further more oxygen addition could promote the removal efficiency of hydrogen sulfide (about 93.6 %), the oxygen residue in biogas would be higher than the application limit concentration (0.5 %). Whether mesophilic or thermophilic fermentation with the extra addition of oxygen, there were no obvious changes in the gas production and methane concentration. In conclusion, in-situ desulfurization can be achieved in the anaerobic methane fermentation system under micro-oxygen environment. In addition, air could be used as a substitute oxygen resource on the situation without strict demand for the methane content of biogas.

Engineering of the redox imbalance of Fusarium oxysporum enables anaerobic growth on xylose

DEFF Research Database (Denmark)

Panagiotou, Gianni; Christakopoulos, Paul; Grotkjær, Thomas

2006-01-01

Dissimilatory nitrate reduction metabolism, of the natural xylose-fermenting fungus Fusarium oxysporum, was used as a strategy to achieve anaerobic growth and ethanol production from xylose. Beneficial alterations of the redox fluxes and thereby of the xylose metabolism were obtained by taking ad...

Anaerobic and aerobic batch cultivations of Saccharomyces cerevisiae mutants impaired in glycerol synthesis

DEFF Research Database (Denmark)

Nissen, Torben Lauesgaard; Hamann, Claus Wendelboe; Kielland-Brandt, M. C.

2000-01-01

Glycerol is formed as a by-product in production of ethanol and baker's yeast during fermentation of Saccharomyces cerevisiae under anaerobic and aerobic growth conditions, respectively. One physiological role of glycerol formation by yeast is to reoxidize NADH, formed in synthesis of biomass...

Mistletoe lectin I in complex with galactose and lactose reveals distinct sugar-binding properties

International Nuclear Information System (INIS)

Mikeska, Ruth; Wacker, Roland; Arni, Raghuvir; Singh, Tej P.; Mikhailov, Albert; Gabdoulkhakov, Azat; Voelter, Wolfgang; Betzel, Christian

2004-01-01

The structures of mistletoe lectin I in complex with lactose and galactose reveal differences in binding by the two known sites in subdomains α1 and γ2 and suggest the presence of a third low-affinity site in subdomain β1. The structures of mistletoe lectin I (ML-I) from Viscum album complexed with lactose and galactose have been determined at 2.3 Å resolution and refined to R factors of 20.9% (R free = 23.6%) and 20.9 (R free = 24.6%), respectively. ML-I is a heterodimer and belongs to the class of ribosome-inactivating proteins of type II, which consist of two chains. The A-chain has rRNA N-glycosidase activity and irreversibly inhibits eukaryotic ribosomes. The B-chain is a lectin and preferentially binds to galactose-terminated glycolipids and glycoproteins on cell membranes. Saccharide binding is performed by two binding sites in subdomains α1 and γ2 of the ML-I B-chain separated by ∼62 Å from each other. The favoured binding of galactose in subdomain α1 is achieved via hydrogen bonds connecting the 4-hydroxyl and 3-hydroxyl groups of the sugar moiety with the side chains of Asp23B, Gln36B and Lys41B and the main chain of 26B. The aromatic ring of Trp38B on top of the preferred binding pocket supports van der Waals packing of the apolar face of galactose and stabilizes the sugar–lectin complex. In the galactose-binding site II of subdomain γ2, Tyr249B provides the hydrophobic stacking and the side chains of Asp235B, Gln238B and Asn256B are hydrogen-bonding partners for galactose. In the case of the galactose-binding site I, the 2-hydroxyl group also stabilizes the sugar–protein complex, an interaction thus far rarely detected in galactose-specific lectins. Finally, a potential third low-affinity galactose-binding site in subunit β1 was identified in the present ML-I structures, in which a glycerol molecule from the cryoprotectant buffer has bound, mimicking the sugar compound

Transient exposure to oxygen or nitrate reveals ecophysiology of fermentative and sulfate‐reducing benthic microbial populations

Science.gov (United States)

Saad, Sainab; Bhatnagar, Srijak; Tegetmeyer, Halina E.; Geelhoed, Jeanine S.; Strous, Marc

2017-01-01

Summary For the anaerobic remineralization of organic matter in marine sediments, sulfate reduction coupled to fermentation plays a key role. Here, we enriched sulfate‐reducing/fermentative communities from intertidal sediments under defined conditions in continuous culture. We transiently exposed the cultures to oxygen or nitrate twice daily and investigated the community response. Chemical measurements, provisional genomes and transcriptomic profiles revealed trophic networks of microbial populations. Sulfate reducers coexisted with facultative nitrate reducers or aerobes enabling the community to adjust to nitrate or oxygen pulses. Exposure to oxygen and nitrate impacted the community structure, but did not suppress fermentation or sulfate reduction as community functions, highlighting their stability under dynamic conditions. The most abundant sulfate reducer in all cultures, related to Desulfotignum balticum, appeared to have coupled both acetate‐ and hydrogen oxidation to sulfate reduction. We describe a novel representative of the widespread uncultured candidate phylum Fermentibacteria (formerly candidate division Hyd24‐12). For this strictly anaerobic, obligate fermentative bacterium, we propose the name ‘USabulitectum silens’ and identify it as a partner of sulfate reducers in marine sediments. Overall, we provide insights into the function of fermentative, as well as sulfate‐reducing microbial communities and their adaptation to a dynamic environment. PMID:28836729

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)

A Novel Millet-Based Probiotic Fermented Food for the Developing World

Directory of Open Access Journals (Sweden)

Elisa Di Stefano

2017-05-01

Full Text Available Probiotic yogurt, comprised of a Fiti sachet containing Lactobacillus rhamnosus GR-1 and Streptococcus thermophilus C106, has been used in the developing world, notably Africa, to alleviate malnutrition and disease. In sub-Saharan African countries, fermentation of cereals such as millet, is culturally significant. The aim of this study was to investigate the fermentation capability of millet when one gram of the Fiti sachet consortium was added. An increase of 1.8 and 1.4 log CFU/mL was observed for S. thermophilus C106 and L. rhamnosus GR-1 when grown in 8% millet in water. Single cultures of L. rhamnosus GR-1 showed the highest μmax when grown in the presence of dextrose, galactose and fructose. Single cultures of S. thermophilus C106 showed the highest μmax when grown in the presence of sucrose and lactose. All tested recipes reached viable counts of the probiotic bacteria, with counts greater than 106 colony-forming units (CFU/mL. Notably, a number of organic acids were quantified, in particular phytic acid, which was shown to decrease when fermentation time increased, thereby improving the bioavailability of specific micronutrients. Millet fermented in milk proved to be the most favorable, according to a sensory evaluation. In conclusion, this study has shown that sachets being provided to African communities to produce fermented milk, can also be used to produce fermented millet. This provides an option for when milk supplies are short, or if communities wish to utilize the nutrient-rich qualities of locally-grown millet.

Impairments of astrocytes are involved in the D-galactose-induced brain aging

International Nuclear Information System (INIS)

Lei Ming; Hua Xiangdong; Xiao Ming; Ding Jiong; Han Qunying; Hu Gang

2008-01-01

Astrocyte dysfunction is implicated in course of various age-related neurodegenerative diseases. Chronic injection of D-galactose can cause a progressive deterioration in learning and memory capacity and serve as an animal model of aging. To investigate the involvement of astrocytes in this model, oxidative stress biomarkers, biochemical and pathological changes of astrocytes were examined in the hippocampus of the rats with six weeks of D-galactose injection. D-galactose-injected rats displayed impaired antioxidant systems, an increase in nitric oxide levels, and a decrease in reduced glutathione levels. Consistently, western blotting and immunostaining of glial fibrillary acidic protein showed extensive activation of astrocytes. Double-immunofluorescent staining further showed activated astrocytes highly expressed inducible nitric oxide synthase. Electron microscopy demonstrated the degeneration of astrocytes, especially in the aggregated area of synapse and brain microvessels. These findings indicate that impairments of astrocytes are involved in oxidative stress-induced brain aging by chronic injection of D-galactose

What is alcoholic fermentation? A study about the alcoholic fermentation conception through the history

Directory of Open Access Journals (Sweden)

C.A. F. Cardoso

2004-05-01

Full Text Available This work shows the historical development of the alcoholic fermentation conception, based on expe-rimental results obtained from European scientists, from Renascence to the beginning of 20th century(1930. From this, ve concepts were identied for the phenomenon: putrefactive, spiritual, chemical,biological and biochemical. The current conception of alcoholic fermentation was also evaluated. Forthis proposal, three groups of teachers were interviewed through the question? What is alcoholicfermentation? The P group (pilot, n=12 made of professionals that teach on secondary and highschools, group A composed of PhDs from the Center of Technology Education - NUTES (n=9 andgroup B from Department of Medical Biochemistry (called group B, n=41 both of Federal Universityof Rio de Janeiro, respectively. Key words associated with the fermentative process were identiedidentify in the interviewees answers. The group A components mentioned only six key words andpointed out the alcoholic fermentation products. Dierently, subjects from P and B groups cited ahigher number and also more unusual key words (n = 9 and 12, respectively. We also analyzedtheir answers throughout fermentative descriptive words (sugar, alcohol, carbon dioxide, anaerobic,yeast and ATP. These words were established after an evaluation of alcoholic fermentation conceptstated in the Biology/Biochemistry books most adopted in high schools and Universities. Our analysisshowed that group A used only three descriptive words (sugar, alcohol and yeast while componentsof group B used all the selected descriptive words. However, only one interviewee used all the sixwords together. From this analysis, we proposed that the chemical concept of alcoholic fermentationprevailed on the other concepts found on the historical research (spiritual, putrefactive, biological ebiochemical.

Effect of different phosphates on the manurial value of aerobically fermented cowdung in the production of combustible gas

Energy Technology Data Exchange (ETDEWEB)

Sen, A; Paul, N B; Rewari, R B

1956-01-01

N content of cow dung was increased by anaerobic fermentation (for combustible gas production), though to a lesser extent if phosphates were added. Rates of nitrification of the fermented manure in soil were low and were not improved by P additions; the manure consequently induced little response in rice, but it improved pea yields considerably.

The correlation between mannanase and cellulase activities towards fibre content of palm oil sludge fermented with Aspergillus niger

Directory of Open Access Journals (Sweden)

T. Purwadaria

1998-12-01

Full Text Available Enzyme (mannanase and cellulase activities and fibre (hemicellulose, cellulose and lignin contents were determined during the fermentation course of palm oil sludge with Aspergillus niger TL (wild type and A. niger ES I (an asporogenous mutant. The analyses were carried out at the incubation time of 3 and 4 days of aerobic fennentation and at 2 days of anaerobic fermentation afterward. The correlations between mamlanase activity with hemicellulose content and cellulose activity with cellulose content were calculated by linear regression . The activities of matutanase and cellulase are increasing during the aerobic fennentation, while in the anaerobic fennentation the enzyme activities are decreasing due to instability of the enzymes. The enzyme activities of ESI are higher than the TL. The regression coefficient is highly significant for correlation between mamlanase and hemicellulose content of fermented product by ESI (r = 0.83; P0 .05 . Marutanase and cellulase activities were also detected after the fermented product dried at 60°C which indicated the enzymes are quite stable .

Elucidating Flux Regulation of the Fermentation Modes of Lactococcus lactis

DEFF Research Database (Denmark)

Chan, Siu Hung Joshua

an important subject for basic research in cellular metabolism because L. lactis exhibits an interesting metabolic shift. Under anaerobic conditions, on fast fermentable sugars, L. lactis produces lactate as the primary product, known as homolactic fermentation but on slowly fermentable sugars, significant...... amounts of formate, acetate and ethanol are formed, known as mixed-acid fermentation. This shift is termed the mixedacid shift. This type of shift between a low-yield and a high-yield metabolism has drawn a lot of research focus and has similarly been observed in other bacteria, yeast and even tumor cells....... Efforts have been put to find out the mechanism regulating the mixed-acid shift as well as to answer questions such as why L. lactis prefers such a switch. Until now, some pieces of evidence have been reported and several factors and models have been proposed as the keys to regulating the shift, including...

Anaerobic digestion in combination with 2nd generation ethanol production for maximizing biofuels yield from lignocellulosic biomass – testing in an integrated pilot-scale biorefinery plant

DEFF Research Database (Denmark)

Uellendahl, Hinrich; Ahring, Birgitte Kiær

An integrated biorefinery concept for 2nd generation bioethanol production together with biogas production from the fermentation effluent was tested in pilot-scale. The pilot plant comprised pretreatment, enzymatic hydrolysis, hexose and pentose fermentation into ethanol and anaerobic digestion......-VS/(m3•d) a methane yield of 340 L/kg-VS was achieved for thermophilic operation while 270 L/kg-VS was obtained under mesophilic conditions. Thermophilic operation was, however, less robust towards further increase of the loading rate and for loading rates higher than 5 kg-VS/(m3•d) the yield was higher...... for mesophilic than for thermophilic operation. The effluent from the ethanol fermentation showed no signs of toxicity to the anaerobic microorganisms. Implementation of the biogas production from the fermentation effluent accounted for about 30% higher biofuels yield in the biorefinery compared to a system...

Introducing capnophilic lactic fermentation in a combined dark-photo fermentation process: a route to unparalleled H2 yields.

Science.gov (United States)

Dipasquale, L; Adessi, A; d'Ippolito, G; Rossi, F; Fontana, A; De Philippis, R

2015-01-01

Two-stage process based on photofermentation of dark fermentation effluents is widely recognized as the most effective method for biological production of hydrogen from organic substrates. Recently, it was described an alternative mechanism, named capnophilic lactic fermentation, for sugar fermentation by the hyperthermophilic bacterium Thermotoga neapolitana in CO2-rich atmosphere. Here, we report the first application of this novel process to two-stage biological production of hydrogen. The microbial system based on T. neapolitana DSM 4359(T) and Rhodopseudomonas palustris 42OL gave 9.4 mol of hydrogen per mole of glucose consumed during the anaerobic process, which is the best production yield so far reported for conventional two-stage batch cultivations. The improvement of hydrogen yield correlates with the increase in lactic production during capnophilic lactic fermentation and takes also advantage of the introduction of original conditions for culturing both microorganisms in minimal media based on diluted sea water. The use of CO2 during the first step of the combined process establishes a novel strategy for biohydrogen technology. Moreover, this study opens the way to cost reduction and use of salt-rich waste as feedstock.

Recovery of anaerobic digestion after exposure to toxicants. Final report

Energy Technology Data Exchange (ETDEWEB)

Yang, J.; Parkin, G.F.; Speece, R.E.

1979-12-01

The concept that methane fermentation cannot tolerate chronic or slug doses of toxicants has almost totally precluded methane fermentation as a viable contender for the treatment of industrial wastewaters. This study assayed a wide variety of toxicants, heavy metals, inorganic salts, organic chemicals, solvents, and antibiotics which are used in industrial processes and, therefore, appear in the industrial wastewaters therefrom. Toxicity was related to the reduction in methane production of a control containing no toxicant. The response of methane fermentation after exposure to a toxicant was assayed with unacclimated cultures as well as cultures which had been acclimated to increasing concentrations of the toxicant over long periods of time. The reversible nature of the toxicants was assayed by adding slug doses to plug flow anaerobic filters and recording gas production prior to, during, and after toxicant addition.

Protective effect of curcumin (Curcuma longa) against D-galactose-induced senescence in mice.

Science.gov (United States)

Kumar, Anil; Prakash, Atish; Dogra, Samrita

2011-01-01

Brain senescence plays an important role in cognitive dysfunction and neurodegenerative disorders. Curcumin was reported to have beneficial effect against several neurodegenerative disorders including Alzheimer's disease. Therefore, the present study was conducted in order to explore the possible role of curcumin against D-galactose-induced cognitive dysfunction, oxidative damage, and mitochondrial dysfunction in mice. Chronic administration of D-galactose for 6 weeks significantly impaired cognitive function (both in Morris water maze and elevated plus maze), locomotor activity, oxidative defense (raised lipid peroxidation, nitrite concentration, depletion of reduced glutathione and catalase activity), and mitochondrial enzyme complex activities (I, II, and III) as compared to vehicle treated group. Curcumin (15 and 30 mg/kg) and galantamine (5 mg/kg) treatment for 6 weeks significantly improved cognitive tasks, locomotor activity, oxidative defense, and restored mitochondrial enzyme complex activity as compared to control (D-galactose). Chronic D-galactose treatment also significantly increased acetylcholine esterase activity that was attenuated by curcumin (15 and 30 mg/kg) and galantamine (5 mg/kg) treatment. In conclusion, the present study highlights the therapeutic potential of curcumin against d-galactose induced senescence in mice.

Bio-hydrogen production from waste fermentation. Mixing and static conditions

Energy Technology Data Exchange (ETDEWEB)

Gomez, X.; Cuetos, M.J.; Prieto, J.I.; Moran, A. [Chemical Engineering Dept. IRENA, University of Leon, Avda. de Portugal 41, 24071 Leon (Spain)

2009-04-15

One of the main disadvantages of the dark fermentation process is the cost associated with the stages needed for obtaining H{sub 2} producing microorganisms. Using anaerobic microflora in fermentation systems directly is an alternative which is gaining special interest when considering the implementation of large-scale plants and the use of wastes as substrate material. The performance of two H{sub 2} producing microflora obtained from different anaerobic cultures was studied in this paper. Inoculum obtained from a waste sludge digester and from a laboratory digester treating slaughterhouse wastes were used to start up H{sub 2} fermentation systems. Inoculum acclimatized to slaughterhouse wastes gave better performance in terms of stability. However, due to the limited availability of this seed material, further work was performed to study the behaviour of the inoculum obtained from the municipal wastewater treatment plant. The process was evaluated under static and mixing conditions. It was found that application of a low organic loading rate favoured the performance of the fermentation systems, and that agitation of the reacting mass could alleviate unsteady performance. Specific H{sub 2} production obtained was in the range of 19-26 L/kg SV{sub fed} with maximum peak production of 38-67 L/kg SV{sub fed}. Although the performance of the systems was unsteady, recovery could be achieved by suspending the feeding process and controlling the pH in the range of 5.0-5.5. Testing the recovery capacity of the systems under temperature shocks resulted in total stoppage of H{sub 2} production. (author)

Modeling of the substrate and product transfer coefficients for ethanol fermentation

International Nuclear Information System (INIS)

Zerajic, S.; Grbavcic, Z.; Savkovic-Stevanovic, J.

2008-01-01

The transfer phenomena of the substrate and product for ethanol fermentation with immobilized biocatalyst were investigated. Fermentation was carried out with a biocatalyst consisting of Ca-alginate gel in the form of two-layer spherical beads in anaerobic conditions. The determination of kinetic parameters was achieved by fitting bioreaction progress curves to the experimental data. The calculation of the diffusion coefficients was performed by numerical methods for experimental conditions. Finally, the glucose and ethanol transfer coefficients are defined and determined, using the effective diffusion coefficients. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Selective conversion of carbon monoxide to hydrogen by anaerobic mixed culture.

Science.gov (United States)

Liu, Yafeng; Wan, Jingjing; Han, Sheng; Zhang, Shicheng; Luo, Gang

2016-02-01

A new method for the conversion of CO to H2 was developed by anaerobic mixed culture in the current study. Higher CO consumption rate was obtained by anaerobic granular sludge (AGS) compared to waste activated sludge (WAS) at 55 °C and pH 7.5. However, H2 was the intermediate and CH4 was the final product. Fermentation at pH 5.5 by AGS inhibited CH4 production, while the lower CO consumption rate (50% of that at pH 7.5) and the production of acetate were found. Fermentation at pH 7.5 with the addition of chloroform achieved efficient and selective conversion of CO to H2. Stable and efficient H2 production was achieved in a continuous reactor inoculated with AGS, and gas recirculation was crucial to increase the CO conversion efficiency. Microbial community analysis showed that high abundance (44%) of unclassified sequences and low relative abundance (1%) of known CO-utilizing bacteria Desulfotomaculum were enriched in the reactor. Copyright © 2015 Elsevier Ltd. All rights reserved.

GalX regulates the d-galactose oxido-reductive pathway in Aspergillus niger

NARCIS (Netherlands)

Gruben, B.S.; Zhou, M.; de Vries, R.P.

2012-01-01

Galactose catabolism in Aspergillus nidulans is regulated by at least two regulators, GalR and GalX. In Aspergillus niger only GalX is present, and its role in d-galactose catabolism in this fungus was investigated. Phenotypic and gene expression analysis of a wild type and a galX disruptant

Electrochemically Driven Fermentation of Organic Substrates with Undefined Mixed Microbial Cultures.

Science.gov (United States)

Villano, Marianna; Paiano, Paola; Palma, Enza; Miccheli, Alfredo; Majone, Mauro

2017-08-10

Growing scientific interest in mixed microbial culture-based anaerobic biotechnologies for the production of value-added chemicals and fuels from organic waste residues requires a parallel focus on the development and implementation of strategies to control the distribution of products. This study examined the feasibility of an electrofermentation approach, based on the introduction of a polarized (-700 mV vs. the standard hydrogen electrode) graphite electrode in the fermentation medium, to steer the product distribution during the conversion of organic substrates (glucose, ethanol, and acetate supplied as single compounds or in mixtures) by undefined mixed microbial cultures. In batch experiments, the polarized electrode triggered a nearly 20-fold increase (relative to open circuit controls) in the yield of isobutyrate production (0.43±0.01 vs. 0.02±0.02 mol mol -1 glucose) during the anaerobic fermentation of the ternary mixture of substrates, without adversely affecting the rate of substrate bioconversion. The observed change in the fermentative metabolism was most likely triggered by the (potentiostatic) regulation of the oxidation-reduction potential of the reaction medium rather than by the electrode serving as an electron donor. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Industrial symbiosis: corn ethanol fermentation, hydrothermal carbonization, and anaerobic digestion.

Science.gov (United States)

Wood, Brandon M; Jader, Lindsey R; Schendel, Frederick J; Hahn, Nicholas J; Valentas, Kenneth J; McNamara, Patrick J; Novak, Paige M; Heilmann, Steven M

2013-10-01

The production of dry-grind corn ethanol results in the generation of intermediate products, thin and whole stillage, which require energy-intensive downstream processing for conversion into commercial animal feed products. Hydrothermal carbonization of thin and whole stillage coupled with anaerobic digestion was investigated as alternative processing methods that could benefit the industry. By substantially eliminating evaporation of water, reductions in downstream energy consumption from 65% to 73% were achieved while generating hydrochar, fatty acids, treated process water, and biogas co-products providing new opportunities for the industry. Processing whole stillage in this manner produced the four co-products, eliminated centrifugation and evaporation, and substantially reduced drying. With thin stillage, all four co-products were again produced, as well as a high quality animal feed. Anaerobic digestion of the aqueous product stream from the hydrothermal carbonization of thin stillage reduced chemical oxygen demand (COD) by more than 90% and converted 83% of the initial COD to methane. Internal use of this biogas could entirely fuel the HTC process and reduce overall natural gas usage. Copyright © 2013 Wiley Periodicals, Inc.

Degradation of plant wastes by anaerobic process using rumen bacteria.

Science.gov (United States)

Seon, J; Creuly, C; Duchez, D; Pons, A; Dussap, C G

2003-01-01

An operational reactor has been designed for the fermentation of a pure culture of Fibrobacter succinogenes with the constraints of strict anaerobic condition. The process is controlled by measurements of pH, redox, temperature and CO2 pressure; it allows an efficient degradation (67%) of lignocellulosic wastes such as a mixture of wheat straw, soya bean cake and green cabbage.

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.

Water permeation through the sodium-dependent galactose cotransporter vSGLT.

Science.gov (United States)

Choe, Seungho; Rosenberg, John M; Abramson, Jeff; Wright, Ernest M; Grabe, Michael

2010-10-06

It is well accepted that cotransporters facilitate water movement by two independent mechanisms: osmotic flow through a water channel in the protein and flow driven by ion/substrate cotransport. However, the molecular mechanism of transport-linked water flow is controversial. Some researchers believe that it occurs via cotransport, in which water is pumped along with the transported cargo, while others believe that flow is osmotic in response to an increase in intracellular osmolarity. In this letter, we report the results of a 200-ns molecular dynamics simulation of the sodium-dependent galactose cotransporter vSGLT. Our simulation shows that a significant number of water molecules cross the protein through the sugar-binding site in the presence as well as the absence of galactose, and 70-80 water molecules accompany galactose as it moves from the binding site into the intracellular space. During this event, the majority of water molecules in the pathway are unable to diffuse around the galactose, resulting in water in the inner half of the transporter being pushed into the intracellular space and replaced by extracellular water. Thus, our simulation supports the notion that cotransporters act as both passive water channels and active water pumps with the transported substrate acting as a piston to rectify the motion of water. Copyright © 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Effects of Compound Yi-Zhi on D-galactose-induced learning and memory deficits in mice

Institute of Scientific and Technical Information of China (English)

XUJiang-Ping; WUHang-Yu; LILin

2004-01-01

AIM: To explore the effects of Compound Yi-Zhi (YZC) on learning and memory capacity and free radical metabolism in D-galactose induced mice dementia model. METHODS: The mice dementia model was induced by a daily D-galactose 0.15g/kg sc for 45 days and after 5 days'D-galactose injection, the mice were treated with three doses of YZC

Fermentative production of isobutene.

Science.gov (United States)

van Leeuwen, Bianca N M; van der Wulp, Albertus M; Duijnstee, Isabelle; van Maris, Antonius J A; Straathof, Adrie J J

2012-02-01

Isobutene (2-methylpropene) is one of those chemicals for which bio-based production might replace the petrochemical production in the future. Currently, more than 10 million metric tons of isobutene are produced on a yearly basis. Even though bio-based production might also be achieved through chemocatalytic or thermochemical methods, this review focuses on fermentative routes from sugars. Although biological isobutene formation is known since the 1970s, extensive metabolic engineering is required to achieve economically viable yields and productivities. Two recent metabolic engineering developments may enable anaerobic production close to the theoretical stoichiometry of 1isobutene + 2CO(2) + 2H(2)O per mol of glucose. One relies on the conversion of 3-hydroxyisovalerate to isobutene as a side activity of mevalonate diphosphate decarboxylase and the other on isobutanol dehydration as a side activity of engineered oleate hydratase. The latter resembles the fermentative production of isobutanol followed by isobutanol recovery and chemocatalytic dehydration. The advantage of a completely biological route is that not isobutanol, but instead gaseous isobutene is recovered from the fermenter together with CO(2). The low aqueous solubility of isobutene might also minimize product toxicity to the microorganisms. Although developments are at their infancy, the potential of a large scale fermentative isobutene production process is assessed. The production costs estimate is 0.9 Euro kg(-1), which is reasonably competitive. About 70% of the production costs will be due to the costs of lignocellulose hydrolysate, which seems to be a preferred feedstock.

Anaerobic biological treatment of in-situ retort water

Energy Technology Data Exchange (ETDEWEB)

Ossio, E.; Fox, P.

1980-03-01

Anaerobic fermentation was successfully used in a laboratory-scale batch digester to remove soluble organics from retort water. Required pretreatment includes reduction of ammonia levels to 360 mg-N/l, pH adjustment to 7.0, sulfide control, and the addition of the nutrients, calcium, magnesium, and phoshorus. If the prescribed pretreatment is used, BOD/sub 5/ and COD removal efficiencies of 89 to 90% and 65 to 70% are achieved, respectively.

New generation biofuel from whey: Successive acidogenesis and alcoholic fermentation using immobilized cultures on γ-alumina

International Nuclear Information System (INIS)

Boura, Konstantina; Kandylis, Panagiotis; Bekatorou, Argyro; Kolliopoulos, Dionysios; Vasileiou, Dimitrios; Panas, Panayiotis; Kanellaki, Maria; Koutinas, Athanasios A.

2017-01-01

Highlights: • Successive continuous alcoholic fermentation and acidogenesis of whey. • UASB culture (acidogenesis) and kefir (alcoholic fermentation) fixed on γ-alumina. • Alcoholic fermentation-acidogenesis process led to 10-fold higher ethanol content. • Organic acids production was increased by 2.5-fold. • The process is promising for new generation ester-based biofuels from whey. - Abstract: Cheese whey exploitation in a biorefinery manner is proposed involving anaerobic acidogenesis by a UASB mixed anaerobic culture and alcoholic fermentation by kefir. Both cultures were immobilized on γ-alumina. The produced organic acids (OAs) and ethanol could be esterified to obtain a novel ester-based biofuel similar to biodiesel. During acidogenesis, lactic acid-type fermentation occurred leading to 12 g L"−"1 total OAs and 0.2 g L"−"1 ethanol. The fermented substrate was subsequently supplied to a second bioreactor with immobilized kefir, which increased the OAs content (15 g L"−"1), especially lactic acid, and slightly the ethanol concentration (0.3–0.4 g L"−"1). To further increase ethanol concentration, a second experiment was conducted supplying whey firstly to the immobilized kefir bioreactor and then pumping the effluent into the acidogenesis bioreactor, resulting in 40% increase of OAs and 10-fold higher ethanol content. The residual sugar was ∼50% of the initial whey lactose; consequently, future research could result to further increase of ethanol and OAs.

Lactate production as representative of the fermentation potential of Corynebacterium glutamicum 2262 in a one-step process.

Science.gov (United States)

Khuat, Hoang Bao Truc; Kaboré, Abdoul Karim; Olmos, Eric; Fick, Michel; Boudrant, Joseph; Goergen, Jean-Louis; Delaunay, Stéphane; Guedon, Emmanuel

2014-01-01

The fermentative properties of thermo-sensitive strain Corynebacterium glutamicum 2262 were investigated in processes coupling aerobic cell growth and the anaerobic fermentation phase. In particular, the influence of two modes of fermentation on the production of lactate, the fermentation product model, was studied. In both processes, lactate was produced in significant amount, 27 g/L in batch culture, and up to 55.8 g/L in fed-batch culture, but the specific production rate in the fed-batch culture was four times lower than that in the batch culture. Compared to other investigated fermentation processes, our strategy resulted in the highest yield of lactic acid from biomass. Lactate production by C. glutamicum 2262 thus revealed the capability of the strain to produce various fermentation products from pyruvate.

Simultaneous localization of an hepatic binding protein specific for galactose and of galactose-containing receptors on rat hepatocytes.

Science.gov (United States)

Horisberger, M; VonLanthen, M

1978-11-01

The hepatic binding protein, specific for galactose-terminated glycoproteins (asialoglycoproteins) and the receptors for the Ricinus communis lectin, specific for galactose residues (RCA1), were simultaneously localized on isolated rat hepatocytes by the gold method. The marker for the binding protein was prepared from gold granules (5 nm in diam.) labeled with ceruloplasmin and desialylated. The marker specific for galactose-containing receptors consisted of granules (17 nm in diameter) labeled with RCA1. It was established that both markers did not interact. Hepatocytes (fresh or briefly fixed with glutaraldehyde) were successively incubated with the asialoceruloplasmin and the RCA1 marker. Examination of thin sections by electron microscopy indicated that the binding protein and the RCA1 receptors were often in the proximity of each other on the plasmamembrane. Using the same technique, wheat germ agglutinin (WGA) receptors were generally found on area of the plasmamembrane poorly marked by the RCA1 gold marker. The binding of asialoceruloplasmin gold markers was studied as a function of the size of the granules. It became insignificant when the size was above 17 nm. Previous results have shown that the binding of RCA1 is low when the marker reaches 50 nm in size while WGA markers up to 75 nm are well bound by hepatocytes. It is therefore hypothesized that the binding protein and RCA1 receptors are located between glycoprotein brushes of increasing spacing while part or all of the WGA receptors are located at the periphery of the brushes.

Alcohol dehydrogenase gene ADH3 activates glucose alcoholic fermentation in genetically engineered Dekkera bruxellensis yeast

DEFF Research Database (Denmark)

Schifferdecker, Anna Judith; Siurkus, Juozas; Andersen, Mikael Rørdam

2016-01-01

Dekkera bruxellensis is a non-conventional Crabtree-positive yeast with a good ethanol production capability. Compared to Saccharomyces cerevisiae, its tolerance to acidic pH and its utilization of alternative carbon sources make it a promising organism for producing biofuel. In this study, we...... developed an auxotrophic transformation system and an expression vector, which enabled the manipulation of D. bruxellensis, thereby improving its fermentative performance. Its gene ADH3, coding for alcohol dehydrogenase, was cloned and overexpressed under the control of the strong and constitutive promoter...... TEF1. Our recombinant D. bruxellensis strain displayed 1.4 and 1.7 times faster specific glucose consumption rate during aerobic and anaerobic glucose fermentations, respectively; it yielded 1.2 times and 1.5 times more ethanol than did the parental strain under aerobic and anaerobic conditions...

Flux-Enabled Exploration of the Role of Sip1 in Galactose Yeast Metabolism

Directory of Open Access Journals (Sweden)

Christopher M. Shymansky

2017-05-01

Full Text Available 13C metabolic flux analysis (13C MFA is an important systems biology technique that has been used to investigate microbial metabolism for decades. The heterotrimer Snf1 kinase complex plays a key role in the preference Saccharomyces cerevisiae exhibits for glucose over galactose, a phenomenon known as glucose repression or carbon catabolite repression. The SIP1 gene, encoding a part of this complex, has received little attention, presumably, because its knockout lacks a growth phenotype. We present a fluxomic investigation of the relative effects of the presence of galactose in classically glucose-repressing media and/or knockout of SIP1 using a multi-scale variant of 13C MFA known as 2-Scale 13C metabolic flux analysis (2S-13C MFA. In this study, all strains have the galactose metabolism deactivated (gal1Δ background so as to be able to separate the metabolic effects purely related to glucose repression from those arising from galactose metabolism. The resulting flux profiles reveal that the presence of galactose in classically glucose-repressing conditions, for a CEN.PK113-7D gal1Δ background, results in a substantial decrease in pentose phosphate pathway (PPP flux and increased flow from cytosolic pyruvate and malate through the mitochondria toward cytosolic branched-chain amino acid biosynthesis. These fluxomic redistributions are accompanied by a higher maximum specific growth rate, both seemingly in violation of glucose repression. Deletion of SIP1 in the CEN.PK113-7D gal1Δ cells grown in mixed glucose/galactose medium results in a further increase. Knockout of this gene in cells grown in glucose-only medium results in no change in growth rate and a corresponding decrease in glucose and ethanol exchange fluxes and flux through pathways involved in aspartate/threonine biosynthesis. Glucose repression appears to be violated at a 1/10 ratio of galactose-to-glucose. Based on the scientific literature, we may have conducted our experiments

Dark fermentation, anaerobic digestion and microbial fuel cells: An integrated system to valorize swine manure and rice bran.

Science.gov (United States)

Schievano, Andrea; Sciarria, Tommy Pepè; Gao, Yong Chang; Scaglia, Barbara; Salati, Silvia; Zanardo, Marina; Quiao, Wei; Dong, Renjie; Adani, Fabrizio

2016-10-01

This work describes how dark fermentation (DF), anaerobic digestion (AD) and microbial fuel cells (MFC) and solid-liquid separation can be integrated to co-produce valuable biochemicals (hydrogen and methane), bioelectricity and biofertilizers. Two integrated systems (System 1: AD+MFC, and System 2: DF+AD+MFC) are described and compared to a traditional one-stage AD system in converting a mixture (COD=124±8.1gO2kg(-1)Fresh Matter) of swine manure and rice bran. System 1 gave a biomethane yield of 182 LCH4kg(-1)COD-added, while System 2 gave L yields of bio-hydrogen and bio-methane of 27.3±7.2LH2kg(-1)COD-added and 154±14LCH4kg(-1)COD-added, respectively. A solid-liquid separation (SLS) step was applied to the digested slurry, giving solid and liquid fractions. The liquid fraction was treated via the MFC-steps, showing power densities of 12-13Wm(-3) (500Ω) and average bioelectricity yields of 39.8Whkg(-1)COD to 54.2Whkg(-1)COD. Copyright © 2016 Elsevier Ltd. All rights reserved.

Transient exposure to oxygen or nitrate reveals ecophysiology of fermentative and sulfate-reducing benthic microbial populations.

Science.gov (United States)

Saad, Sainab; Bhatnagar, Srijak; Tegetmeyer, Halina E; Geelhoed, Jeanine S; Strous, Marc; Ruff, S Emil

2017-12-01

For the anaerobic remineralization of organic matter in marine sediments, sulfate reduction coupled to fermentation plays a key role. Here, we enriched sulfate-reducing/fermentative communities from intertidal sediments under defined conditions in continuous culture. We transiently exposed the cultures to oxygen or nitrate twice daily and investigated the community response. Chemical measurements, provisional genomes and transcriptomic profiles revealed trophic networks of microbial populations. Sulfate reducers coexisted with facultative nitrate reducers or aerobes enabling the community to adjust to nitrate or oxygen pulses. Exposure to oxygen and nitrate impacted the community structure, but did not suppress fermentation or sulfate reduction as community functions, highlighting their stability under dynamic conditions. The most abundant sulfate reducer in all cultures, related to Desulfotignum balticum, appeared to have coupled both acetate- and hydrogen oxidation to sulfate reduction. We describe a novel representative of the widespread uncultured candidate phylum Fermentibacteria (formerly candidate division Hyd24-12). For this strictly anaerobic, obligate fermentative bacterium, we propose the name ' U Sabulitectum silens' and identify it as a partner of sulfate reducers in marine sediments. Overall, we provide insights into the function of fermentative, as well as sulfate-reducing microbial communities and their adaptation to a dynamic environment. © 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

Anaerobic catabolism of aromatic compounds: a genetic and genomic view.

Science.gov (United States)

Carmona, Manuel; Zamarro, María Teresa; Blázquez, Blas; Durante-Rodríguez, Gonzalo; Juárez, Javier F; Valderrama, J Andrés; Barragán, María J L; García, José Luis; Díaz, Eduardo

2009-03-01

Aromatic compounds belong to one of the most widely distributed classes of organic compounds in nature, and a significant number of xenobiotics belong to this family of compounds. Since many habitats containing large amounts of aromatic compounds are often anoxic, the anaerobic catabolism of aromatic compounds by microorganisms becomes crucial in biogeochemical cycles and in the sustainable development of the biosphere. The mineralization of aromatic compounds by facultative or obligate anaerobic bacteria can be coupled to anaerobic respiration with a variety of electron acceptors as well as to fermentation and anoxygenic photosynthesis. Since the redox potential of the electron-accepting system dictates the degradative strategy, there is wide biochemical diversity among anaerobic aromatic degraders. However, the genetic determinants of all these processes and the mechanisms involved in their regulation are much less studied. This review focuses on the recent findings that standard molecular biology approaches together with new high-throughput technologies (e.g., genome sequencing, transcriptomics, proteomics, and metagenomics) have provided regarding the genetics, regulation, ecophysiology, and evolution of anaerobic aromatic degradation pathways. These studies revealed that the anaerobic catabolism of aromatic compounds is more diverse and widespread than previously thought, and the complex metabolic and stress programs associated with the use of aromatic compounds under anaerobic conditions are starting to be unraveled. Anaerobic biotransformation processes based on unprecedented enzymes and pathways with novel metabolic capabilities, as well as the design of novel regulatory circuits and catabolic networks of great biotechnological potential in synthetic biology, are now feasible to approach.

Adaptively evolved yeast mutants on galactose show trade-offs in carbon utilization on glucose

DEFF Research Database (Denmark)

Hong, Kuk-Ki; Nielsen, Jens

2013-01-01

the molecular mechanisms. In this study, adaptively evolved yeast mutants with improved galactose utilization ability showed impaired glucose utilization. The molecular genetic basis of this trade-off was investigated using a systems biology approach. Transcriptional and metabolic changes resulting from...... the improvement of galactose utilization were found maintained during growth on glucose. Moreover, glucose repression related genes showed conserved expression patterns during growth on both sugars. Mutations in the RAS2 gene that were identified as beneficial for galactose utilization in evolved mutants...

Auxin-induced modifications of cell wall polysaccharides in cat coleoptile segments. Effect of galactose

International Nuclear Information System (INIS)

Yamamoto, R.; Masuda, Y.

1984-01-01

Galactose inhibits auxin-induced cell elongation in oat coleoptile segments. Cell elongation induced by exogenously applied auxin is controlled by factors such as auxin uptake, cell wall loosening, osmotic concentration of sap and hydraulic conductivity. However, galactose does not have any effect on these factors. The results discussed in this paper led to the conclusion that galactose does not affect cell wall loosening which controls rapid growth, but inhibits cell wall synthesis which is required to maintain long-term growth

/sup 14/C-D-galactose breath test for evaluation of liver function in patients with chronic liver disease

Energy Technology Data Exchange (ETDEWEB)

Caspary, W F; Schaffer, J

1978-01-01

D-galactose metabolism and demethylation of aminopyrine by healthy controls and patients with chronic active hepatitis (CAH) and cirrhosis (Ci), were assessed by a breath analysis technique measuring /sup 14/CO2 exhalation after oral ingestion of /sup 14/C-D-galactose or /sup 14/C-aminopyrine. Patients with CAH and Ci exhibited decreased /sup 14/CO2-exhalation rates following /sup 14/-D-galactose or /sup 14/C-aminopyrine. D-galactose oxidation capacity of the liver can be assessed by a breath analysis technique in analogy to the demethylating function for aminopyrine. The ordinary oral D-galactose tolerance test seems, however, superior in comparison to the /sup 14/C-D-galactose tolerance test, in discriminating between healthy controls and patients with chronic liver disease.

In Silico Identification of Microbial Partners to Form Consortia with Anaerobic Fungi

Directory of Open Access Journals (Sweden)

St. Elmo Wilken

2018-01-01

Full Text Available Lignocellulose is an abundant and renewable resource that holds great promise for sustainable bioprocessing. However, unpretreated lignocellulose is recalcitrant to direct utilization by most microbes. Current methods to overcome this barrier include expensive pretreatment steps to liberate cellulose and hemicellulose from lignin. Anaerobic gut fungi possess complex cellulolytic machinery specifically evolved to decompose crude lignocellulose, but they are not yet genetically tractable and have not been employed in industrial bioprocesses. Here, we aim to exploit the biomass-degrading abilities of anaerobic fungi by pairing them with another organism that can convert the fermentable sugars generated from hydrolysis into bioproducts. By combining experiments measuring the amount of excess fermentable sugars released by the fungal enzymes acting on crude lignocellulose, and a novel dynamic flux balance analysis algorithm, we screened potential consortia partners by qualitative suitability. Microbial growth simulations reveal that the fungus Anaeromyces robustus is most suited to pair with either the bacterium Clostridia ljungdahlii or the methanogen Methanosarcina barkeri—both organisms also found in the rumen microbiome. By capitalizing on simulations to screen six alternative organisms, valuable experimental time is saved towards identifying stable consortium members. This approach is also readily generalizable to larger systems and allows one to rationally select partner microbes for formation of stable consortia with non-model microbes like anaerobic fungi.

Fermentative hydrogen production from cassava stillage by mixed anaerobic microflora: Effects of temperature and pH

Energy Technology Data Exchange (ETDEWEB)

Luo, Gang; Xie, Li; Zou, Zhonghai; Zhou, Qi [Key Laboratory of Yangtze River Water Environment, Ministry of Education (Tongji University), UNEP-Tongji, Tongji University, Siping Road No. 1239, Shanghai 200092 (China); Wang, Jing-Yuan (School of Civil and Environmental Engineering, Nanyang Technological University, N1-01b-45, 50 Nanyang Avenue, 639798 Singapore)

2010-12-15

Fermentative hydrogen production from cassava stillage was conducted to investigate the influences of temperature (37 C, 60 C, 70 C) and initial pH (4-10) in batch experiments. Although the seed sludge was mesophilic anaerobic sludge, maximum hydrogen yield (53.8 ml H{sub 2}/gVS) was obtained under thermophilic condition (60 C), 53.5% and 198% higher than the values under mesophilic (37 C) and extreme-thermophilic (70 C) conditions respectively. The difference was mainly due to the different VFA and ethanol distributions. Higher hydrogen production corresponded with higher ratios of butyrate/acetate and butyrate/propionate. Similar hydrogen yields of 66.3 and 67.8 ml H{sub 2}/gVS were obtained at initial pH 5 and 6 respectively under thermophilic condition. The total amount of VFA and ethanol increased from 3536 to 7899 mg/l with the increase of initial pH from 4 to 10. Initial pH 6 was considered as the optimal pH due to its 19% higher total VFA and ethanol concentration than that of pH 5. Homoacetogenesis and methonogenesis were very dependent on the initial pH and temperature even when the inoculum was heat-pretreated. Moreover, a difference between measured and theoretical hydrogen was observed in this study, which could be attributed to homoacetogenesis, methanogenesis and the degradation of protein. (author)

Cumulative antioxidant defense against oxidative challenge in galactose-induced cataractogenesis in Wistar rats.

Science.gov (United States)

Raju, T N; Kumar, C Sanat; Kanth, V Rajani; Ramana, B Venkata; Reddy, P Uma Maheswara; Suryanarayana, P; Reddy, G Bhanuprakash

2006-09-01

Natural dietary ingredients are known for their antioxidant activity. Of such, curcumin, the active principle of turmeric, at 0.01% in the diet proved as pro-oxidative in galactose-induced cataract in vivo. The purpose of this study was to investigate the effect of vitamin E (VE), a well-known antioxidant, in combination with curcumin on the onset and maturation of galactose induced cataract. Periodic slit-lamp microscope examination indicated that in combination with vitamin-E, 0.01% curcumin (G-IV) delayed the onset and maturation of galactose-induced cataract. Biochemical analyses revealed that combined treatment of 0.01% curcumin and vitamin-E diet exhibited an efficient antioxidant effect, as it inhibited lipid peroxidation and contributed to a distinct rise in reduced glutathione content. The results indicate that natural dietary ingredients are effective in combination rather than the individual administration as they are complementing each other in reducing the risk of galactose induced cataract.

Enhanced bioenergy recovery from oil-extracted microalgae residues via two-step H2/CH4 or H2/butanol anaerobic fermentation.

Science.gov (United States)

Cheng, Hai-Hsuan; Whang, Liang-Ming; Wu, Shu-Hsien

2016-03-01

Algae-based biodiesel is considered a promising alternative energy; therefore, the treatment of microalgae residues would be necessary. Anaerobic processes can be used for treating oil-extracted microalgae residues (OMR) and at the same time for recovering bioenergy. In this study, anaerobic batch experiments were conducted to evaluate the potential of recovering bioenergy, in the forms of butanol, H2, or CH4, from pretreated OMR. Using pretreated OMR as the only substrate, a butanol yield of 0.086 g/g-carbohydrate was obtained at carbohydrate of 40 g/L. With supplemented butyrate, a highest butanol yield of 0.192 g/g-carbohydrate was achieved at pretreated OMR containing 25 g/L of carbohydrate with 15 g/L of butyrate addition, attaining the highest energy yield of 3.92 kJ/g-OMR and energy generation rate of 0.65 kJ/g-OMR/d. CH4 production from pretreated OMR attained an energy yield of 8.83 kJ/g-OMR, but energy generation rate required further improvement. H2 production alone from pretreated OMR might not be attractive regarding energy yield, but it attained a superb energy generation rate of 0.68 kJ/g-OMR/d by combining H2 production from pretreated OMR and butanol production from pretreated OMR with supplementary butyrate from H2 fermentation supernatant. This study demonstrated an integrated system as an option for treating OMR and recovering bioenergy. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Methane production enhancement by an independent cathode in integrated anaerobic reactor with microbial electrolysis

DEFF Research Database (Denmark)

Cai, Weiwei; Han, Tingting; Guo, Zechong

2016-01-01

Anaerobic digestion (AD) represents a potential way to achieve energy recovery from waste organics. In this study, a novel bioelectrochemically-assisted anaerobic reactor is assembled by two AD systems separated by anion exchange membrane, with the cathode placing in the inside cylinder (cathodic...... fermentation liquid, methane production rate has been further increased to 0.247 mL CH4/mL reactor/day (increased by 51.53% comparing with AD control). Energy recovery efficiency presents profitable gains, and economic revenue from increased methane totally self-cover the cost of input electricity. The study...

6th Conference 'Anaerobic treatment of biological wastes'. New tendencies in the biogas technology; 6. Fachtagung Anaerobe biologische Abfallbehandlung. Neue Tendenzen in der Biogastechnologie

Energy Technology Data Exchange (ETDEWEB)

Bilitewski, B.; Werner, P.; Dornack, Christina; Stegmann, R.; Rettenberger, G.; Faulstich, M.; Wittmaier, M. (eds.)

2008-07-01

Within this 6th conference at 23rd to 24th September, 2008, in Dresden (Federal Republic of Germany), the following lectures were held: (1) Development of biogas technology - influences and tendencies (H. Friedmann); (2) EEG 2009 - Effect on biogas branch (B. Dreher); (3) From composting to fermentation - material flows, technology, cost, practical experiences (M. Kern, T. Raussen, A. Lootsma, K. Funda); (4) Fermentation of vinasses from the production of bioethanol (H. Friedmann); (5) Substrate digestion and microbiological hydrolysis for biogas production from lignocellulosis containing substrates using beer draff as an example (D. Schieder, M. Faulstich, J. Voigt, J. Ellenriedere, B. Haeffner, K. Sommer); (6) Substitution of wheat and corn by grass and manure for improving the economic efficiency of biogas plants (M. Wittmaier); (7) High-efficiency anaerobic digestion with integrated micro filtration using clarification sludge as an example (W. Troesch, B. Kempter-Regel); (8) Modelling of anaerobic digestion; stationary and dynamic parameter of estimation (C. Cimatoribus); (9) Regulation of an anaerobic laboratory reactor by means of fuzzy logic (O. Bade); (10) Model based diagnosis of the state of process in biogas plants (W. Kloeden); (11) Suitability of ADM 1 in the modelling of biogas plants (K. Koch, M. Wichern, M. Luebken, H. Horn, M. Schlattmann, A. Gronauer); (12) Load dependent and automatical operation of biogas plants - an option for the future (M. Mueller, J. Proeter, F. Scholwin); (13) Chances for biogas generation and application in Vietnam (L. van Bot, M. Wittmaier, A. Karagiannidies, B. Bilitewski, P. Werner); (14) State of the art and developments in the fermentation of biological wastes in the Peoples Republic of China (M. Gehring, R. Li, B. Raininger); (15) Bio-methane potential from cattle and pig wastes in Greece (A. Karagiannidis, G. Perkoulidis, T. Kotsopoulos); (16) Contaminants in biogas plants - an assessment of the material flow using

Critical factors affecting the integration of biomass gasification and syngas fermentation technology

Directory of Open Access Journals (Sweden)

Karthikeyan D. Ramachandriya

2016-05-01

Full Text Available Gasification-fermentation is a thermochemical-biological platform for the production of fuels and chemicals. Biomass is gasified at high temperatures to make syngas, a gas composed of CO, CO2, H2, N2 and other minor components. Syngas is then fed to anaerobic microorganisms that convert CO, CO2 and H2 to alcohols by fermentation. This platform offers numerous advantages such as flexibility of feedstock and syngas composition and lower operating temperature and pressure compared to other catalytic syngas conversion processes. In comparison to hydrolysis-fermentation, gasification-fermentation has a major advantage of utilizing all organic components of biomass, including lignin, to yield higher fuel production. Furthermore, syngas fermentation microorganisms do not require strict CO:H2:CO2 ratios, hence gas reforming is not required. However, several issues must be addressed for successful deployment of gasification-fermentation, particularly those that involve the integration of gasification and fermentation. Most previous reviews have focused only on either biomass gasification or syngas fermentation. In this review, the critical factors that affect the integration of biomass gasification with syngas fermentation, such as carbon conversion efficiency, effect of trace gaseous species, H2 to CO ratio requirements, and microbial preference of carbon substrate, are thoroughly discussed.

An efficient synthesis of D-galactose-based multivalent neoglycoconjugates

Energy Technology Data Exchange (ETDEWEB)

Andrade, S.F. de; Souza Filho, J.D. de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Inst. de Ciencias Exatas. Dept. de Quimica; Alves, Ricardo J., E-mail: ricardodylan@farmacia.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Fac. de Farmacia; Figueiredo, Rute C. [Universidade Federal de Ouro Preto (UFOP), MG (Brazil)

2012-11-15

In this work, the synthesis of dimeric, trimeric and tetrameric D-galactose-based neoglycoconjugates is reported. The monosaccharide ligand was prepared in 5 straightforward steps from D-galactose using the Doebner modification of the Knoevenagel reaction for chain elongation. The ligand was coupled to 1,4-butanediamine, tris-(2-ethylamino)amine, pentaerythrityltetramine and PAMAM dendrimers (1,4-butanodiamine core G0 and 1,12-dodecanediamine core G0). The unprotected glycodendrimers were purified by size-exclusion chromatography (SEC). This was the only step in which a chromatographic method was employed throughout the synthetic route. This is a new and efficient strategy for the preparation of neoglycoconjugates. (author)

In vitro fermentation of alternansucrase raffinose acceptor products by human gut bacteria

Science.gov (United States)

In this work, in vitro fermentation of alternansucrase raffinose acceptor products, previously fractionated according to their degree of polymerization (DP; from DP4 to DP10) was carried out using pH-controlled small scale batch cultures at 37ºC under anaerobic conditions with human faeces. Bifidog...

Fermentative utilization of coffee mucilage using Bacillus coagulans and investigation of down-stream processing of fermentation broth for optically pure l(+)-lactic acid production.

Science.gov (United States)

Neu, Anna-Katrin; Pleissner, Daniel; Mehlmann, Kerstin; Schneider, Roland; Puerta-Quintero, Gloria Inés; Venus, Joachim

2016-07-01

In this study, mucilage, a residue from coffee production, was investigated as substrate in fermentative l(+)-lactic acid production. Mucilage was provided as liquid suspension consisting glucose, galactose, fructose, xylose and sucrose as free sugars (up to 60gL(-1)), and used directly as medium in Bacillus coagulans batch fermentations carried out at 2 and 50L scales. Using mucilage and 5gL(-1) yeast extract as additional nitrogen source, more than 40gL(-1) lactic acid was obtained. Productivity and yield were 4-5gL(-1)h(-1) and 0.70-0.77g lactic acid per g of free sugars, respectively, irrespective the scale. Similar yield was found when no yeast extract was supplied, the productivity, however, was 1.5gL(-1)h(-1). Down-stream processing of culture broth, including filtration, electrodialysis, ion exchange chromatography and distillation, resulted in a pure lactic acid formulation containing 930gL(-1)l(+)-lactic acid. Optical purity was 99.8%. Copyright © 2016 Elsevier Ltd. All rights reserved.

Study on the correlation between volatile fatty acids and gas production in dry fermentation of kitchen waste

Science.gov (United States)

Li, Qiangqiang; Ma, Yunfeng; Du, Boying; Wang, Qi; Hu, Qiongqiong; Bian, Yushan

2018-02-01

In this study, continuous kitchen waste fermentation and anaerobic digestion experiments were conducted to analyze the gas production potential, and to study the correlation between gas production rate and volatile fatty acid (VFAs) and its component concentration. During the experiment, the total solid(TS) concentration of the reaction system was increased by adding the kitchen waste, analysis of kitchen waste dry fermentation process to start, run, imbalance and imbalance after recovery and the parameters in the process of realizing the change trend and influencing factors of dry fermentation process, pH and ammonia concentration.

Pretreatment of wheat straw and conversion of xylose and xylan to ethanol by thermophilic anaerobic bacteria

DEFF Research Database (Denmark)

Ahring, Birgitte Kiær; Jensen, K.; Nielsen, P.

1996-01-01

solubilization was investigated. The two process parameters had little effect on the solubilization of hemicellulose. However alkaline conditions affected the furfural formation whereas oxygen had no effect. After pretreatment, the filtrate was used as a fermentation medium for thermophilic anaerobic bacterin...

Methane-yielding microbial communities processing lactate-rich substrates: a piece of the anaerobic digestion puzzle.

Science.gov (United States)

Detman, Anna; Mielecki, Damian; Pleśniak, Łukasz; Bucha, Michał; Janiga, Marek; Matyasik, Irena; Chojnacka, Aleksandra; Jędrysek, Mariusz-Orion; Błaszczyk, Mieczysław K; Sikora, Anna

2018-01-01

Anaerobic digestion, whose final products are methane and carbon dioxide, ensures energy flow and circulation of matter in ecosystems. This naturally occurring process is used for the production of renewable energy from biomass. Lactate, a common product of acidic fermentation, is a key intermediate in anaerobic digestion of biomass in the environment and biogas plants. Effective utilization of lactate has been observed in many experimental approaches used to study anaerobic digestion. Interestingly, anaerobic lactate oxidation and lactate oxidizers as a physiological group in methane-yielding microbial communities have not received enough attention in the context of the acetogenic step of anaerobic digestion. This study focuses on metabolic transformation of lactate during the acetogenic and methanogenic steps of anaerobic digestion in methane-yielding bioreactors. Methane-yielding microbial communities instead of pure cultures of acetate producers were used to process artificial lactate-rich media to methane and carbon dioxide in up-flow anaerobic sludge blanket reactors. The media imitated the mixture of acidic products found in anaerobic environments/digesters where lactate fermentation dominates in acidogenesis. Effective utilization of lactate and biogas production was observed. 16S rRNA profiling was used to examine the selected methane-yielding communities. Among Archaea present in the bioreactors, the order Methanosarcinales predominated. The acetoclastic pathway of methane formation was further confirmed by analysis of the stable carbon isotope composition of methane and carbon dioxide. The domain Bacteria was represented by Bacteroidetes , Firmicutes , Proteobacteria , Synergistetes , Actinobacteria , Spirochaetes , Tenericutes , Caldithrix , Verrucomicrobia , Thermotogae , Chloroflexi , Nitrospirae, and Cyanobacteria. Available genome sequences of species and/or genera identified in the microbial communities were searched for genes encoding the lactate

Anaerobic Metabolism: Linkages to Trace Gases and Aerobic Processes

Science.gov (United States)

Megonigal, J. P.; Hines, M. E.; Visscher, P. T.

2003-12-01

's surface area, they have a profound influence on the biogeochemistry of the planet. This is evident from the observation that the O2 and CH4 content of Earth's atmosphere are in extreme disequilibrium (Sagan et al., 1993). The combination of high aerobic primary production and anoxic sediments provided the large deposits of fossil fuels that have become vital and contentious sources of energy for modern industrialized societies. Anaerobic metabolism is responsible for the abundance of N2 in the atmosphere; otherwise N2-fixing bacteria would have consumed most of the N2 pool long ago (Schlesinger, 1997). Anaerobic microorganisms are common symbionts of termites, cattle, and many other animals, where they aid digestion. Nutrient and pollutant chemistry are strongly modified by the reduced conditions that prevail in wetland and aquatic ecosystems.This review of anaerobic metabolism emphasizes aerobic oxidation, because the two processes cannot be separated in a complete treatment of the topic. It is process oriented and highlights the fascinating microorganisms that mediate anaerobic biogeochemistry. We begin this review with a brief discussion of CO2 assimilation by autotrophs, the source of most of the reducing power on Earth, and then consider the biological processes that harness this potential energy. Energy liberation begins with the decomposition of organic macromolecules to relatively simple compounds, which are simplified further by fermentation. Methanogenesis is considered next because CH4 is a product of acetate fermentation, and thus completes the catabolism of organic matter, particularly in the absence of inorganic electron acceptors. Finally, the organisms that use nitrogen, manganese, iron, and sulfur for terminal electron acceptors are considered in order of decreasing free-energy yield of the reactions.

Benznidazole induces in vitro anaerobic metabolism in Trypanosoma cruzi epimastigotes

Directory of Open Access Journals (Sweden)

Marina Clare Vinaud

2017-11-01

Full Text Available Objective: To determine the biochemical alterations of the energetic metabolism of Trypanosoma cruzi epimastigotes in vitro exposed to different concentrations of benzinidazole. Methods: Biochemical analyses were performed at 3, 6 (log phase, 9 and 12 (stationary phase days of culture. Parasites were exposed to five concentrations of benzinidazole. Glycolysis, tricarboxilic acid cycle and fatty acids oxidation pathways were quantified through chromatography. Glucose, urea and creatinine were quantified through spectrophotometric analysis. Results: Anaerobic fermentation and fatty acids oxidation were increased in the stationary phase of the culture. Benzinidazole at high concentrations induced anaerobic metabolism in the log phase of the culture while the parasites exposed to the lower concentrations preferred the citric acid cycle as energy production pathway. Benzinidazole did not influence on the proteins catabolism. Conclusions: It is possible to conclude that there are metabolic differences between evolutive forms of Trypanosoma cruzi and the main drug used for its treatment induces the anaerobic metabolism in the parasite, possibly impairing the mitochondrial pathways.

Application of a tetrazolium dye as an indicator of viability in anaerobic bacteria.

Science.gov (United States)

Bhupathiraju, V K; Hernandez, M; Landfear, D; Alvarez-Cohen, L

1999-09-01

The use of the redox dye 5-cyano-2,3,-ditolyl tetrazolium chloride (CTC) for evaluating the metabolic activity of aerobic bacteria has gained wide application in recent years. In this study, we examined the utility of CTC in capturing the metabolic activity of anaerobic bacteria. In addition, the factors contributing to abiotic reduction of CTC were also examined. CTC was used in conjunction with the fluorochrome 5-(4,6-dichlorotriazinyl) aminofluorescein (DTAF), that targets bacterial cell wall proteins, to quantitate the active fraction of total bacterial numbers. Facultative anaerobic bacteria, including Escherichia coli grown fermentatively, and Pseudomonas chlorophis, P. fluorescens, P. stutzeri, and P. pseudoalcalegenes subsp. pseudoalcalegenes grown under nitrate-reducing conditions, actively reduced CTC during all phases of growth. Greater than 95% of these cells accumulated intracellular CTC-formazan crystals during the exponential phase. Obligate anaerobic bacteria, including Syntrophus aciditrophicus grown fermentatively, Geobacter sulfurreducens grown with fumarate as the electron acceptor, Desulfovibrio desulfuricans subsp. desulfuricans and D. halophilus grown under sulfate-reducing conditions, Methanobacterium formicicum grown on formate, H2 and CO2, and Methanobacterium thermoautotrophicum grown autotrophically on H2 and CO2 all reduced CTC to intracellular CTC-formazan crystals. The optimal CTC concentration for all organisms examined was 5 mM. Anaerobic CTC incubations were not required for quantification of anaerobically grown cells. CTC-formazan production by all cultures examined was proportional to biomass production, and CTC reduction was observed even in the absence of added nutrients. CTC was reduced by culture fluids containing ferric citrate as electron acceptor following growth of either G. metallireducens or G. sulfurreducens. Abiotic reduction of CTC was observed in the presence of ascorbic acid, cysteine hydrochloride, dithiothreitol

Morphology and physiology of the dimorphic fungus Mucor circinelloides (syn. M. racemosus) during anaerobic growth

DEFF Research Database (Denmark)

Lübbehüsen, Tina Louise; Nielsen, Jens; Mcintyre, Mhairi

2003-01-01

The dimorphic Mucor circinelloides requires an anaerobic atmosphere and the presence of 30% CO2 to grow as a multipolar budding yeast, otherwise hyphal growth predominates. Establishing other means to control the morphology would be a distinct advantage in the development of a fermentation process...

Expanding a dynamic flux balance model of yeast fermentation to genome-scale

Science.gov (United States)

2011-01-01

Background Yeast is considered to be a workhorse of the biotechnology industry for the production of many value-added chemicals, alcoholic beverages and biofuels. Optimization of the fermentation is a challenging task that greatly benefits from dynamic models able to accurately describe and predict the fermentation profile and resulting products under different genetic and environmental conditions. In this article, we developed and validated a genome-scale dynamic flux balance model, using experimentally determined kinetic constraints. Results Appropriate equations for maintenance, biomass composition, anaerobic metabolism and nutrient uptake are key to improve model performance, especially for predicting glycerol and ethanol synthesis. Prediction profiles of synthesis and consumption of the main metabolites involved in alcoholic fermentation closely agreed with experimental data obtained from numerous lab and industrial fermentations under different environmental conditions. Finally, fermentation simulations of genetically engineered yeasts closely reproduced previously reported experimental results regarding final concentrations of the main fermentation products such as ethanol and glycerol. Conclusion A useful tool to describe, understand and predict metabolite production in batch yeast cultures was developed. The resulting model, if used wisely, could help to search for new metabolic engineering strategies to manage ethanol content in batch fermentations. PMID:21595919

Effect of Germination and Fermentation on Carbohydrate Composition of Australian Sweet Lupin and Soybean Seeds and Flours.

Science.gov (United States)

Kaczmarska, Kornelia T; Chandra-Hioe, Maria V; Zabaras, Dimitrios; Frank, Damian; Arcot, Jayashree

2017-11-22

This study investigated the effect of germination and fermentation on the composition of carbohydrates in Australian sweet lupin. Specifically, the amount of sugars (sucrose, fructose, and glucose), starch, oligosaccharides (verbascose, stachyose, and raffinose), and dietary fiber were measured in germinated lupin seeds and fermented lupin flour, and compared with those in soy. High performance liquid chromatography coupled with refractive index was employed for quantitation of sugars, starch, and oligosaccharides, and gas chromatography coupled with a flame ionization detector was used for quantitation of simple sugars in total, and soluble, and insoluble dietary fiber. The enzyme activities of α-amylase and α-glucosidase were compared before and after germination or fermentation. The α-amylase activity in germinated lupin increased to  ∼17 nmol/mL/min/0.1 g and in germinated soy∼32; in fermented lupin, the activity increased to ∼52, while in fermented soy it decreased to ∼20. In general, germination or fermentation decreased the oligosaccharide content, and increased the total sugar in samples (p Fermentation with yogurt culture lowered the content of total oligosaccharides due to 94% decrease in stachyose. Total oligosaccharides in soy flour prior to fermentation were 180 mg/g and significantly decreased to ∼124 mg/g in fermented soy. Germination did not affect the starch content. There was no significant change in the amounts of total, soluble, and insoluble dietary fiber after germination or fermentation of lupin except for galactose, which was significantly reduced in germinated lupin seeds. Soluble dietary fiber in germinated soy significantly increased. Germination and fermentation are simple and effective techniques to reduce the oligosaccharides while maintaining the composition of dietary fibers.

Increased albumin permeation in eyes, aorta, and kidney of hypertensive rats fed galactose

International Nuclear Information System (INIS)

Tilton, R.G.; LaRose, L.; Chang, K.; Weigel, C.J.; Williamson, J.R.

1986-01-01

These experiments were undertaken to determine whether ingestion of galactose increases albumin permeation in the vasculature of hypertensive rats. 50% dextrin (control) or 50% galactose diets were fed to unilaterally nephrectomized, male Sprague-Dawley rats weighing 200 g. Hypertension (systolic pressure >175 mmHg) was induced by weekly IM injections of 25 mg/kg DOCA and 1% saline drinking water; 3 months later 125 I-albumin permeation was assessed in whole eyes, aorta and kidneys. 125 I-albumin permeation was significantly increased in all 3 tissues of hypertensive rats (n = 9) vs controls (n = 9): aorta (3.30 +/- 0.19 (SD) vs 2.87 +/- 0.14), eye (3.15 +/- 0.14 vs 2.59 +/- 0.11), and kidney (6.58 +/- 0.63 vs 3.85 +/- 0.50). Albumin permeation was increased still further in hypertensive rats fed the galactose diet (n = 8): aorta (3.75 +/- 0.38), eye (3.82 +/- 0.17), and kidney (10.74 +/- 3.13). Hypertension +/- galactose feeding had no effect on albumin permeation in lung, skin, or brain. These findings indicate that: (1) hypertension increases albumin permeation in vessels affected by diabetic vascular diseases, and 2) hypertension-induced increases in albumin permeation are increased still further by galactose ingestion, presumably mediated by imbalances in polyol/insitol metabolism (analogous to those induced by diabetes) independent of hyperglycemia and/or insulinopenia

Gaining electricity from in situ oxidation of hydrogen produced by fermentative cellulose degradation.

Science.gov (United States)

Niessen, J; Schröder, U; Harnisch, F; Scholz, F

2005-01-01

To exploit the fermentative hydrogen generation and direct hydrogen oxidation for the generation of electric current from the degradation of cellulose. Utilizing the metabolic activity of the mesophilic anaerobe Clostridium cellulolyticum and the thermophilic Clostridium thermocellum we show that electricity generation is possible from cellulose fermentation. The current generation is based on an in situ oxidation of microbially synthesized hydrogen at platinum-poly(tetrafluoroaniline) (Pt-PTFA) composite electrodes. Current densities of 130 mA l(-1) (with 3 g cellulose per litre medium) were achieved in poised potential experiments under batch and semi-batch conditions. The presented results show that electricity generation is possible by the in situ oxidation of hydrogen, product of the anaerobic degradation of cellulose by cellulolytic bacteria. For the first time, it is shown that an insoluble complex carbohydrate like cellulose can be used for electricity generation in a microbial fuel cell. The concept represents a first step to the utilization of macromolecular biomass components for microbial electricity generation.

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.

Economics of membrane occupancy and respiro-fermentation

Science.gov (United States)

Zhuang, Kai; Vemuri, Goutham N; Mahadevan, Radhakrishnan

2011-01-01

The simultaneous utilization of efficient respiration and inefficient fermentation even in the presence of abundant oxygen is a puzzling phenomenon commonly observed in bacteria, yeasts, and cancer cells. Despite extensive research, the biochemical basis for this phenomenon remains obscure. We hypothesize that the outcome of a competition for membrane space between glucose transporters and respiratory chain (which we refer to as economics of membrane occupancy) proteins influences respiration and fermentation. By incorporating a sole constraint based on this concept in the genome-scale metabolic model of Escherichia coli, we were able to simulate respiro-fermentation. Further analysis of the impact of this constraint revealed differential utilization of the cytochromes and faster glucose uptake under anaerobic conditions than under aerobic conditions. Based on these simulations, we propose that bacterial cells manage the composition of their cytoplasmic membrane to maintain optimal ATP production by switching between oxidative and substrate-level phosphorylation. These results suggest that the membrane occupancy constraint may be a fundamental governing constraint of cellular metabolism and physiology, and establishes a direct link between cell morphology and physiology. PMID:21694717

Interaction between lactic acid bacteria and yeasts in airag, an alcoholic fermented milk.

Science.gov (United States)

Sudun; Wulijideligen; Arakawa, Kensuke; Miyamoto, Mari; Miyamoto, Taku

2013-01-01

The interaction between nine lactic acid bacteria (LAB) and five yeast strains isolated from airag of Inner Mongolia Autonomic Region, China was investigated. Three representative LAB and two yeasts showed symbioses were selected and incubated in 10% (w/v) reconstituted skim milk as single and mixed cultures to measure viable count, titratable acidity, ethanol and sugar content every 24 h for 1 week. LAB and yeasts showed high viable counts in the mixed cultures compared to the single cultures. Titratable acidity of the mixed cultures was obviously enhanced compared with that of the single cultures, except for the combinations of Lactobacillus reuteri 940B3 with Saccharomyces cerevisiae 4C and Lactobacillus helveticus 130B4 with Candida kefyr 2Y305. C. kefyr 2Y305 produced large amounts of ethanol (maximum 1.35 g/L), whereas non-lactose-fermenting S. cerevisiae 4C produced large amounts of ethanol only in the mixed cultures. Total glucose and galactose content increased while lactose content decreased in the single cultures of Leuconostoc mesenteroides 6B2081 and Lb. helveticus 130B4. However, both glucose and galactose were completely consumed and lactose was markedly reduced in the mixed cultures with yeasts. The result suggests that yeasts utilize glucose and galactose produced by LAB lactase to promote cell growth. © 2012 The Authors. Animal Science Journal © 2012 Japanese Society of Animal Science.

Transcriptional, proteomic, and metabolic responses to lithium in galactose-grown yeast cells

DEFF Research Database (Denmark)

Bro, Christoffer; Regenberg, Birgitte; Lagniel, G.

2003-01-01

Lithium is highly toxic to yeast when grown in galactose medium mainly because phosphoglucomutase, a key enzyme of galactose metabolism, is inhibited. We studied the global protein and gene expression profiles of Saccharomyces cerevisiae grown in galactose in different time intervals after addition...... of lithium. These results were related to physiological studies where both secreted and intracellular metabolites were determined. Microarray analysis showed that 664 open reading frames were down-regulated and 725 up-regulated in response to addition of lithium. Genes involved in transcription, translation......-regulated proteins were also identified as being changed on the mRNA level. Functional clusters obtained from proteome data were coincident with transcriptional clusters. Physiological studies showed that acetate, glycerol, and glycogen accumulate in response to lithium, as reflected in expression data, whereas...

The effect of the fungicide captan on Saccharomyces cerevisiae and wine fermentation

Directory of Open Access Journals (Sweden)

Scariot Fernando J.

2016-01-01

Full Text Available Fungicides, particularly those used during grape maturation, as captan, can affect the natural yeast population of grapes, and can reach grape must affecting wine fermentation. The objective of the present work was to study the effect of captan on the viability and fermentative behavior of S. cerevisiae. S. cerevisiae (BY4741 on exponential phase was treated with captan (0 to 40 μM for different periods, and their cell viability analyzed. Cell membrane integrity, thiols concentration, and reactive oxygen species (ROS accumulation was determined. The fermentation experiments were conducted in synthetic must using wine yeast strain Y904. The results showed that under aerobic conditions, 20 μM of captan reduce 90% of yeast viability in 6 hours. Captan treated cells exhibited alteration of membrane integrity, reduction of thiol compounds and increase in intracellular ROS concentration, suggesting a necrotic and pro-oxidant activity of the fungicide. Fermentative experiments showed that concentrations above 2.5 μM captan completely inhibited fermentation, while a dose dependent fermentation delay associated with the reduction of yeast viability was detected in sub-inhibitory concentrations. Petit mutants increase was also observed. In conclusion, the captan induces yeast necrotic cell death on both aerobic and anaerobic conditions causing fermentation delay and/or sucking fermentations.

Unravelling evolutionary strategies of yeast for improving galactose utilization through integrated systems level analysis.

Science.gov (United States)

Hong, Kuk-Ki; Vongsangnak, Wanwipa; Vemuri, Goutham N; Nielsen, Jens

2011-07-19

Identification of the underlying molecular mechanisms for a derived phenotype by adaptive evolution is difficult. Here, we performed a systems-level inquiry into the metabolic changes occurring in the yeast Saccharomyces cerevisiae as a result of its adaptive evolution to increase its specific growth rate on galactose and related these changes to the acquired phenotypic properties. Three evolved mutants (62A, 62B, and 62C) with higher specific growth rates and faster specific galactose uptake were isolated. The evolved mutants were compared with a reference strain and two engineered strains, SO16 and PGM2, which also showed higher galactose uptake rate in previous studies. The profile of intermediates in galactose metabolism was similar in evolved and engineered mutants, whereas reserve carbohydrates metabolism was specifically elevated in the evolved mutants and one evolved strain showed changes in ergosterol biosynthesis. Mutations were identified in proteins involved in the global carbon sensing Ras/PKA pathway, which is known to regulate the reserve carbohydrates metabolism. We evaluated one of the identified mutations, RAS2(Tyr112), and this mutation resulted in an increased specific growth rate on galactose. These results show that adaptive evolution results in the utilization of unpredicted routes to accommodate increased galactose flux in contrast to rationally engineered strains. Our study demonstrates that adaptive evolution represents a valuable alternative to rational design in bioengineering of improved strains and, that through systems biology, it is possible to identify mutations in evolved strain that can serve as unforeseen metabolic engineering targets for improving microbial strains for production of biofuels and chemicals.

SOLID AND LIQUID PINEAPPLE WASTE UTILIZATION FOR LACTIC ACID FERMENTATION USING Lactobacillus delbrueckii

Directory of Open Access Journals (Sweden)

Abdullah Abdullah

2012-01-01

Full Text Available The liquid and solid  pineapple wastes contain mainly sucrose, glucose, fructose and other nutrients. It therefore can potentially be used as carbon source for fermentation to produce organic acid. Recently, lactic acid has been considered to be an important raw material for production of biodegradable lactate polymer. The experiments were  carried out in batch fermentation using  the  liquid and solid pineapple wastes to produce lactic acid. The anaerobic fermentation of lactic acid were performed at 40 oC, pH 6, 5% inocolum and  50 rpm. Initially  results show that the liquid pineapple waste by  using Lactobacillus delbrueckii can be used as carbon source  for lactic acid fermentation. The production of lactic acid  are found to be 79 % yield, while only  56% yield was produced by using solid waste. 

A comprehensive review on two-stage integrative schemes for the valorization of dark fermentative effluents.

Science.gov (United States)

Sivagurunathan, Periyasamy; Kuppam, Chandrasekhar; Mudhoo, Ackmez; Saratale, Ganesh D; Kadier, Abudukeremu; Zhen, Guangyin; Chatellard, Lucile; Trably, Eric; Kumar, Gopalakrishnan

2017-12-21

This review provides the alternative routes towards the valorization of dark H 2 fermentation effluents that are mainly rich in volatile fatty acids such as acetate and butyrate. Various enhancement and alternative routes such as photo fermentation, anaerobic digestion, utilization of microbial electrochemical systems, and algal system towards the generation of bioenergy and electricity and also for efficient organic matter utilization are highlighted. What is more, various integration schemes and two-stage fermentation for the possible scale up are reviewed. Moreover, recent progress for enhanced performance towards waste stabilization and overall utilization of useful and higher COD present in the organic source into value-added products are extensively discussed.

Caffeine prevents d-galactose-induced cognitive deficits, oxidative stress, neuroinflammation and neurodegeneration in the adult rat brain.

Science.gov (United States)

Ullah, Faheem; Ali, Tahir; Ullah, Najeeb; Kim, Myeong Ok

2015-11-01

d-galactose has been considered a senescent model for age-related neurodegenerative disease. It induces oxidative stress which triggers memory impairment, neuroinflammation and neurodegeneration. Caffeine act as anti-oxidant and has been used in various model of neurodegenerative disease. Nevertheless, the effect of caffeine against d-galactose aging murine model of age-related neurodegenerative disease elucidated. Here, we investigated the neuroprotective effect of caffeine against d-galactose. We observed that chronic treatment of caffeine (3 mg/kg/day intraperitoneally (i.p) for 60 days) improved memory impairment and synaptic markers (Synaptophysin and PSD95) in the d-galactose treated rats. Chronic caffeine treatment reduced the oxidative stress via the reduction of 8-oxoguanine through immunofluorescence in the d-galactose-treated rats. Consequently caffeine treatment suppressed stress kinases p-JNK. Additionally, caffeine treatment significantly reduced the d-galactose-induced neuroinflammation through alleviation of COX-2, NOS-2, TNFα and IL-1β. Furthermore we also analyzed that caffeine reduced cytochrome C, Bax/Bcl2 ratio, caspase-9, caspase-3 and PARP-1 level. Moreover by evaluating the immunohistochemical results of Nissl and Fluro-Jade B staining showed that caffeine prevented the neurodegeneration in the d-galactose-treated rats. Our results showed that caffeine prevents the d-galactose-induced oxidative stress and consequently alleviated neuroinflammation and neurodegeneration; and synaptic dysfunction and memory impairment. Therefore, we could suggest that caffeine might be a dietary anti-oxidant agent and a good candidate for the age-related neurodegenerative disorders. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimization of the integrated citric acid-methane fermentation process by air stripping and glucoamylase addition.

Science.gov (United States)

Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Wang, Ke; Tang, Lei; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

2015-03-01

To solve the problem of extraction wastewater in citric acid industry, an integrated citric acid-methane fermentation process was proposed. In the integrated process, extraction wastewater was treated by mesophilic anaerobic digestion and then reused to make mash for the next batch of citric acid fermentation. In this study, an Aspergillus niger mutant strain exhibiting resistance to high metal ions concentration was used to eliminate the inhibition of 200 mg/L Na(+) and 300 mg/L K(+) in anaerobic digestion effluent (ADE) and citric acid production increased by 25.0 %. Air stripping was used to remove ammonium, alkalinity, and part of metal ions in ADE before making mash. In consequence, citric acid production was significantly improved but still lower by 6.1 % than the control. Results indicated that metal ions in ADE synergistically inhibited the activity of glucoamylase, thus reducing citric acid production. When 130 U/g glucoamylase was added before fermentation, citric acid production was 141.5 g/L, which was even higher than the control (140.4 g/L). This process could completely eliminate extraction wastewater discharge and reduce water resource consumption.

MICROBIAL FERMENTATION OF ABUNDANT BIOPOLYMERS: CELLULOSE AND CHITIN

Energy Technology Data Exchange (ETDEWEB)

Leschine, Susan

2009-10-31

Our research has dealt with seven major areas of investigation: i) characterization of cellulolytic members of microbial consortia, with special attention recently given to Clostridium phytofermentans, a bacterium that decomposes cellulose and produces uncommonly large amounts of ethanol, ii) investigations of the chitinase system of Cellulomonas uda; including the purification and characterization of ChiA, the major component of this enzyme system, iii) molecular cloning, sequence and structural analysis of the gene that encodes ChiA in C. uda, iv) biofilm formation by C. uda on nutritive surfaces, v) investigations of the effects of humic substances on cellulose degradation by anaerobic cellulolytic microbes, vi) studies of nitrogen metabolism in cellulolytic anaerobes, and vii) understanding the molecular architecture of the multicomplex cellulase-xylanase system of Clostridium papyrosolvens. Also, progress toward completing the research of more recent projects is briefly summarized. Major accomplishments include: 1. Characterization of Clostridium phytofermentans, a cellulose-fermenting, ethanol-producing bacterium from forest soil. The characterization of a new cellulolytic species isolated from a cellulose-decomposing microbial consortium from forest soil was completed. This bacterium is remarkable for the high concentrations of ethanol produced during cellulose fermentation, typically more than twice the concentration produced by other species of cellulolytic clostridia. 2. Examination of the use of chitin as a source of carbon and nitrogen by cellulolytic microbes. We discovered that many cellulolytic anaerobes and facultative aerobes are able to use chitin as a source of both carbon and nitrogen. This major discovery expands our understanding of the biology of cellulose-fermenting bacteria and may lead to new applications for these microbes. 3. Comparative studies of the cellulase and chitinase systems of Cellulomonas uda. Results of these studies indicate

Genomic and in Situ Analyses Reveal the Micropruina spp. as Abundant Fermentative Glycogen Accumulating Organisms in Enhanced Biological Phosphorus Removal Systems

Directory of Open Access Journals (Sweden)

Simon J. McIlroy

2018-05-01

Full Text Available Enhanced biological phosphorus removal (EBPR involves the cycling of biomass through carbon-rich (feast and carbon-deficient (famine conditions, promoting the activity of polyphosphate accumulating organisms (PAOs. However, several alternate metabolic strategies, without polyphosphate storage, are possessed by other organisms, which can compete with the PAO for carbon at the potential expense of EBPR efficiency. The most studied are the glycogen accumulating organisms (GAOs, which utilize aerobically stored glycogen to energize anaerobic substrate uptake and storage. In full-scale systems the Micropruina spp. are among the most abundant of the proposed GAO, yet little is known about their ecophysiology. In the current study, genomic and metabolomic studies were performed on Micropruina glycogenica str. Lg2T and compared to the in situ physiology of members of the genus in EBPR plants using state-of-the-art single cell techniques. The Micropruina spp. were observed to take up carbon, including sugars and amino acids, under anaerobic conditions, which were partly fermented to lactic acid, acetate, propionate, and ethanol, and partly stored as glycogen for potential aerobic use. Fermentation was not directly demonstrated for the abundant members of the genus in situ, but was strongly supported by the confirmation of anaerobic uptake of carbon and glycogen storage in the absence of detectable polyhydroxyalkanoates or polyphosphate reserves. This physiology is markedly different from the classical GAO model. The amount of carbon stored by fermentative organisms has potentially important implications for phosphorus removal – as they compete for substrates with the Tetrasphaera PAO and stored carbon is not made available to the “Candidatus Accumulibacter” PAO under anaerobic conditions. This study shows that the current models of the competition between PAO and GAO are too simplistic and may need to be revised to take into account the impact of

The pressure effects on two-phase anaerobic digestion

International Nuclear Information System (INIS)

Chen, Yuling; Rößler, Benjamin; Zielonka, Simon; Lemmer, Andreas; Wonneberger, Anna-Maria; Jungbluth, Thomas

2014-01-01

Highlights: • The pressure effect on anaerobic digestion up to 9 bar was examined. • Increasing pressure decreased pH value in the anaerobic filter. • Increasing pressure increased methane content. • Increasing pressure decreased specific methane yield slightly. • The pressurized methane reactor was very stable and performed well. - Abstract: Two-phase pressurized anaerobic digestion is a novel process aimed at facilitating injection of the produced biogas into the natural gas grid by integrating the fermentative biogas production and upgrading it to substitute natural gas. In order to understand the mechanisms, knowledge of pressure effects on anaerobic digestion is required. To examine the effects of pressure on the anaerobic digestion process, a two-phase anaerobic digestion system was built up in laboratory scale, including three acidogenesis-leach-bed-reactors and one pressure-resistant anaerobic filter. Four different pressure levels (the absolute pressure of 1 bar, 3 bar, 6 bar and 9 bar) were applied to the methane reactor in sequence, with the organic loading rate maintained at approximately 5.1 kgCOD m −3 d −1 . Gas production, gas quality, pH value, volatile fatty acids, alcohol, ammonium-nitrogen, chemical oxygen demand (COD) and alkaline buffer capacity were analyzed. No additional caustic chemicals were added for pH adjustment throughout the experiment. With the pressure increasing from 1.07 bar to 8.91 bar, the pH value decreased from 7.2 to 6.5, the methane content increased from 66% to 75%, and the specific methane yield was slightly reduced from 0.33 l N g −1 COD to 0.31 l N g −1 COD. There was almost no acid-accumulation during the entire experiment. The average COD-degradation grade was always more than 93%, and the average alkaline buffering capacity (VFA/TIC ratio) did not exceed 0.2 at any pressure level. The anaerobic filter showed a very stable performance, regardless of the pressure variation

Acute hypersensitivity reaction to Crotalidae polyvalent immune Fab (CroFab) as initial presentation of galactose-α-1,3-galactose (α-gal) allergy.

Science.gov (United States)

Rizer, Justin; Brill, Kaitlin; Charlton, Nathan; King, Joshua

2017-08-01

Crotalidae polyvalent immune Fab antivenom (CroFab), commonly used for the treatment of clinically significant North American crotalinae envenomation, is generally well-tolerated. A novel form of anaphylaxis due to an IgE antibody response to the mammalian oligosaccharide galactose-α-1,3-galactose (α-gal) has been established following red-meat consumption as well as IV administration of cetuximab, which contain the α-gal epitope. We present a case of α-gal allergy discovered after acute hypersensitivity reaction to FabAV. A 61-year-old healthy female was bitten on her left ankle by Agkistrodon contortrix. Given the patient's rapid progression of pain and swelling, she was given FabAV. During infusion of FabAV, she developed diffuse hives over her entire body and itching, but denied respiratory or gastrointestinal symptoms and her vital signs remained stable. The FabAV was immediately discontinued and she received intravenous diphenhydramine and famotidine with gradual resolution of symptoms. On further discussion, she denied a history of α-gal or papaya allergy but rarely ate red meat and endorsed sustaining frequent tick bites. Subsequent antibody testing was significant for an α-1,3-galactose IgE concentration of 45,000 U/L (normal allergy. To our knowledge, this is the first report of FabAV hypersensitivity associated with an underlying α-gal allergy.

Flux analysis of the human proximal colon using anaerobic digestion model 1.

Science.gov (United States)

Motelica-Wagenaar, Anne Marieke; Nauta, Arjen; van den Heuvel, Ellen G H M; Kleerebezem, Robbert

2014-08-01

The colon can be regarded as an anaerobic digestive compartment within the gastro intestinal tract (GIT). An in silico model simulating the fluxes in the human proximal colon was developed on basis of the anaerobic digestion model 1 (ADM1), which is traditionally used to model waste conversion to biogas. Model calibration was conducted using data from in vitro fermentation of the proximal colon (TIM-2), and, amongst others, supplemented with the bio kinetics of prebiotic galactooligosaccharides (GOS) fermentation. The impact of water and solutes absorption by the host was also included. Hydrolysis constants of carbohydrates and proteins were estimated based on total short chain fatty acids (SCFA) and ammonia production in vitro. Model validation was established using an independent dataset of a different in vitro model: an in vitro three-stage continuous culture system. The in silico model was shown to provide quantitative insight in the microbial community structure in terms of functional groups, and the substrate and product fluxes between these groups as well as the host, as a function of the substrate composition, pH and the solids residence time (SRT). The model confirms the experimental observation that methanogens are washed out at low pH or low SRT-values. The in silico model is proposed as useful tool in the design of experimental setups for in vitro experiments by giving insight in fermentation processes in the proximal human colon. Copyright © 2014. Published by Elsevier Ltd.

Method of preparing (U-14C)-D-galactose

International Nuclear Information System (INIS)

Zemek, J.; Kucar, S.; Kolina, J.

1982-01-01

Whole Chlorella algae cells cultivated in a 14 CO 2 medium were subjected to a β-galactosidase solution buffered to pH=4.5 to 6.0. The produced (U- 14 C)-D-galactose is separated by paper chromatography. (E.S.)

Growth of silicone-immobilized bacteria on polycarbonate membrane filters, a technique to study microcolony formation under anaerobic conditions

DEFF Research Database (Denmark)

Højberg, Ole; Binnerup, S. J.; Sørensen, Jan

1997-01-01

A technique was developed to study microcolony formation by silicone- immobilized bacteria on polycarbonate membrane filters under anaerobic conditions. A sudden shift to anaerobiosis was obtained by submerging the filters in medium which was depleted for oxygen by a pure culture of bacteria....... The technique was used to demonstrate that preinduction of nitrate reductase under low-oxygen conditions was necessary for nonfermenting, nitrate-respiring bacteria, e.g., Pseudomonas spp., to cope with a sudden lack of oxygen. In contrast, nitrate-respiring, fermenting bacteria, e.g., Bacillus and Escherichia...... spp, formed microcolonies under anaerobic conditions with or without the presence of nitrate and irrespective of aerobic or anaerobic preculture conditions....

Synthesis and Excellent Duplex Stability of Oligonucleotides Containing 2'-Amino-LNA Functionalized with Galactose Units

DEFF Research Database (Denmark)

Kumar, Rajesh; Ries, Annika; Wengel, Jesper

2017-01-01

A convenient method for the preparation of oligonucleotides containing internally-attached galactose and triantennary galactose units has been developed based on click chemistry between 2'-N-alkyne 2'-amino-LNA nucleosides and azido-functionalized galactosyl building blocks. The synthesized...

Response of fermentation and sulfate reduction to experimental temperature changes in temperate and Arctic marine sediments

DEFF Research Database (Denmark)

Finke, Niko; Jørgensen, Bo Barker

2008-01-01

Anaerobic degradation of organic material generally proceeds through a sequence of steps, including polymer hydrolysis, fermentation and respiration or methanogenesis. The intermediates, such as volatile fatty acids (VFA) or H(2), are generally maintained at low concentration, showing a close...

Metagenomic insights into anaerobic metabolism along an Arctic peat soil profile.

Directory of Open Access Journals (Sweden)

David A Lipson

Full Text Available A metagenomic analysis was performed on a soil profile from a wet tundra site in northern Alaska. The goal was to link existing biogeochemical knowledge of the system with the organisms and genes responsible for the relevant metabolic pathways. We specifically investigated how the importance of iron (Fe oxides and humic substances (HS as terminal electron acceptors in this ecosystem is expressed genetically, and how respiratory and fermentative processes varied with soil depth into the active layer and into the upper permafrost. Overall, the metagenomes reflected a microbial community enriched in a diverse range of anaerobic pathways, with a preponderance of known Fe reducing species at all depths in the profile. The abundance of sequences associated with anaerobic metabolic processes generally increased with depth, while aerobic cytochrome c oxidases decreased. Methanogenesis genes and methanogen genomes followed the pattern of CH4 fluxes: they increased steeply with depth into the active layer, but declined somewhat over the transition zone between the lower active layer and the upper permafrost. The latter was relatively enriched in fermentative and anaerobic respiratory pathways. A survey of decaheme cytochromes (MtrA, MtrC and their homologs revealed that this is a promising approach to identifying potential reducers of Fe(III or HS, and indicated a possible role for Acidobacteria as Fe reducers in these soils. Methanogens appear to coexist in the same layers, though in lower abundance, with Fe reducing bacteria and other potential competitors, including acetogens. These observations provide a rich set of hypotheses for further targeted study.

The Genetic Requirements for Pentose Fermentation in Budding Yeast

Directory of Open Access Journals (Sweden)

Karin Mittelman

2017-06-01

Full Text Available Cells grow on a wide range of carbon sources by regulating substrate flow through the metabolic network. Incoming sugar, for example, can be fermented or respired, depending on the carbon identity, cell type, or growth conditions. Despite this genetically-encoded flexibility of carbon metabolism, attempts to exogenously manipulate central carbon flux by rational design have proven difficult, suggesting a robust network structure. To examine this robustness, we characterized the ethanol yield of 411 regulatory and metabolic mutants in budding yeast. The mutants showed little variation in ethanol productivity when grown on glucose or galactose, yet diversity was revealed during growth on xylulose, a rare pentose not widely available in nature. While producing ethanol at high yield, cells grown on xylulose produced ethanol at high yields, yet induced expression of respiratory genes, and were dependent on them. Analysis of mutants that affected ethanol productivity suggested that xylulose fermentation results from metabolic overflow, whereby the flux through glycolysis is higher than the maximal flux that can enter respiration. We suggest that this overflow results from a suboptimal regulatory adjustment of the cells to this unfamiliar carbon source.

Fast Startup of Semi-Pilot-Scale Anaerobic Digestion of Food Waste Acid Hydrolysate for Biogas Production.

Science.gov (United States)

Huang, Chao; Zhao, Cheng; Guo, Hai-Jun; Wang, Can; Luo, Mu-Tan; Xiong, Lian; Li, Hai-Long; Chen, Xue-Fang; Chen, Xin-De

2017-12-27

In this study, a fast startup of semi-pilot-scale anaerobic digestion of food waste acid hydrolysate for biogas production was carried out for the first time. During the period of fast startup, more than 85% of chemical oxygen demand (COD) can be degraded, and even more than 90% of COD can be degraded during the later stage of anaerobic digestion. During this anaerobic digestion process, the biogas yield, the methane yield, and the CH 4 content in biogas were 0.542 ± 0.056 m 3 /kg COD consumption , 0.442 ± 0.053 m 3 /kg COD consumption , and 81.52 ± 3.05%, respectively, and these values were high and stable. Besides, the fermentation pH was very stable, in which no acidification was observed during the anaerobic digestion process (outlet pH was 7.26 ± 0.05 for the whole anaerobic digestion). Overall, the startup of this anaerobic digestion can be completed in a short period (the system can be stable 2 days after the substrate was pumped into the bioreactor), and anaerobic digestion of food waste acid hydrolysate is feasible and attractive for industrial treatment of food waste and biogas production.

Cell-to-cell contact and antimicrobial peptides play a combined role in the death of Lachanchea thermotolerans during mixed-culture alcoholic fermentation with Saccharomyces cerevisiae

DEFF Research Database (Denmark)

Kemsawasd, Varongsiri; Branco, Patrícia; Almeida, Maria Gabriela

2015-01-01

The roles of cell-to-cell contact and antimicrobial peptides in the early death of Lachanchea thermotolerans CBS2803 during anaerobic, mixed-culture fermentations with Saccharomyces cerevisiae S101 were investigated using a commercially available, double-compartment fermentation system separated ...

Growth of a Strictly Anaerobic Bacterium on Furfural (2-Furaldehyde)

OpenAIRE

Brune, Gerhard; Schoberth, Siegfried M.; Sahm, Hermann

1983-01-01

A strictly anaerobic bacterium was isolated from a continuous fermentor culture which converted the organic constituents of sulfite evaporator condensate to methane and carbon dioxide. Furfural is one of the major components of this condensate. This furfural isolate could degrade furfural as the sole source of carbon and energy in a defined mineral-vitamin-sulfate medium. Acetic acid was the major fermentation product. This organism could also use ethanol, lactate, pyruvate, or fumarate and c...

Influence of activated carbon amended ASBR on anaerobic fermentative hydrogen production

DEFF Research Database (Denmark)

Xie, Li; Wang, Lei; Zhou, Qi

2013-01-01

The effect of activated carbon amended ASBR on fermentative bio-hydgrogen production from glucose was evaluated at hydraulic retention time (HRTs) ranging from 48 h to 12 h with initial pH of 6.0 at the system temperature of 60°C. Experimental results showed that the performance of activated carbon...... amended anazrobic seguencs batch reactor (ASBRs) was more stable than that of ASBRs without activated carbon addition regarding on hydrogen production and pH. Higher hydrogen yield(HY) and hydrogen producing rate(HPR) were observed in the activated carbon amended ASBRs, with 65%, 63%, 54%, 56% enhancement...... of hydrogen yield in smaller size activated carbon amended reactor under the tested HRT ranges, and the maximum HPR of (7.09±0.31)L·(L·d)-1 and HY of (1.42±0.03) mol·mol-1 was obtained at HRT of 12h. The major soluble products form hydrogen fermentation were n-butyric acid and acetic acid, accounting for 46...

[Isolation and identification of seven thermophilic and anaerobic bacteria from hot springs in Tengchong Rehai].

Science.gov (United States)

Lu, Yueqing; Chen, Bo; Liu, Xiaoli; Ji, Xiuling; Wei, Yunlin; Lin, Lianbing

2009-09-01

In order to study the taxonomic characteristic and physiological, biochemical properties of anaerobic bacteria from hot springs in Tengchong Rehai, Yunnan Province, China. Using Hungate anaerobic technique We isolated seven strains from hot springs in Tengchong Rehai, Yunnan province, and analyzed their 16S rRNA gene sequences. The seven isolates were rod-shaped, Gram-negative, obligate anaerobe, and spores formation was not observed. All strains could grow well at 70 degrees C. Growth of strain RH0802 occurred between 60 and 80 degrees C, optimally around 70 degrees C. The pH range for its growth was between 5.5 and 8.5, with an optimum around 7.0. Strain RH0802 grew on a wide range of carbon sources, including glucose, starch, mannitol, mannose, ribose, maltose, cellobiose, xylose, fructose, galactose, xylan and glycerol, but it could not utilize sucrose or pyruvate. 16S rRNA gene phylogenetic analysis showed that the maximum similarity between the five strains and the strains of genus Caldanaerobacter was up to 98%, except RH0804 and RH0806, which reached to 96% and 93%, respectively. The two isolates were presumed to be potential novel species. The GenBank accession numbers of RH0802 to RH0808 were FJ748766, FJ748762, FJ748761, FJ748763, FJ748765, FJ748764 and FJ748767. The results showed that the seven thermophilic anaerobes belonged to the genus Caldanaerobacter.

Process considerations for use of galactose oxidase as an industrial biocatalyst

DEFF Research Database (Denmark)

Pedersen, Asbjørn Toftgaard; Rehn, Gustav; Woodley, John M.

In nature galactose oxidase (GOase, EC.1.1.3.9) catalyses the oxidation of the C6 hydroxyl group of D-galactose to the corresponding aldehyde, while reducing molecular oxygen to hydrogen peroxide. In recent years a great effort has been made to broaden the substrate scope, enabling GOase to oxidize...... C6-OH of glucose and fructose, as well as secondary alcohols to ketones. The widened substrate scope of GOase opens up many important industrial applications, such as synthesis of industrially relevant compounds containing aldehydes and ketones (e.g. the oxidation of 5-hydroxymethylfurfural...

Content of sugar, organic acids and ethanol in fermented milk beverages obtained with different types of kombucha inoculum

Directory of Open Access Journals (Sweden)

Iličić Mirela D.

2017-01-01

Full Text Available The aim of this study was to examine the influence of different types and concentration of kombucha inoculum on content of sugar, organic acids and ethanol in the fermented beverages produced from milk of 0.9% fat content. Three different kombucha inoculums, cultivated on black tea with addition of sucrose: standard inoculum - 10% (w/w and 15% (w/w, concentrated by microfiltration- 10% (w/w and 15% (w/w, and concentrated by evaporation - 1.5% (w/w and 3.0% (w/w, were applied in the manufacture of fermented milk. Contents of lactose, galactose, glucose, fructose, organic acids, and ethanol in the kombuha fermented milk beverages were determined by the enzyme tests. It was found that the lactose content varied from 3.30 to 4.0 g/100g. All samples showed higher content glucose than fructose. The content of L-lactic acid in the samples ranged from 0.4 to 0.7 g/100g, while significantly lower level of D-lactic and acetic acid were determined in all samples of kombucha fermented milk (<0.06g/100g.[Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 46009

Anaerobic treatment of sulfate-containing wastewater from distilleries

International Nuclear Information System (INIS)

Stadlbauer, E.A.; Oey, L.N.; Weber, B.

1994-01-01

Bioprocess evaluation of a staged arrangement of a Pulse Driven Loop Reaktor (PDLR) and a Pulsed Anaerobic Filter (PAF) using highly polluted cherry slops as industrial wastewater shows a COD removal efficiency of 80-90% at loading rates of 8-4 kg COD/(M 3 .d). Contamination of cherry slops by sulfate (2 g/l) and copper (150-200 mg/l) reduces COD degradation to 40-50 percent. A pulsed anaerobic baffled reactor was envisaged as a corrective tool to improve mineralisation in the presence of sulfate-rich substrates by confining sulfate reducing bacteria to the first 4 chambers of the reactor. Phasing slightly improves COD degradation yield, but is not sufficient for stable process performance. Consequently, the use of lactic acid in stead of sulfuric acid in cherry-fermentation was suggested as a preventive method to avoid sulphide-induced digester failure. (orig.) [de

Anaerobic treatment of olive mill wastewater and piggery effluents fermented with Candida tropicalis

International Nuclear Information System (INIS)

Martinez-Garcia, Gregorio; Johnson, Anbu Clemensis; Bachmann, Robert T.; Williams, Ceri J.; Burgoyne, Andrea; Edyvean, Robert G.J.

2009-01-01

Olive mill wastewater (OMW) contains high concentrations of phenolic compounds that are inhibitory to many microorganisms making it difficult to treat biologically prior to discharge in waterways. The total mono-cyclic phenol reduction in OMW in this study was carried out by aerobic pre-treatment using the yeast Candida tropicalis in a 18 L batch reactor at 30 deg. C for 12 days followed by anaerobic co-digestion. A COD removal of 62% and a reduction in the total mono-cyclic phenol content by 51% of the mixture was achieved in the aerobic pre-treatment. Pig slurry was added as co-substrate to supplement the low nitrogen levels in the olive mill wastewater. Subsequent anaerobic treatment was carried out in a 20 L fixed-bed reactor at 37 deg. C and HRT between 11 and 45 days. After a long start-up period, the OLR was increased from 1.25 to 5 kg COD m -3 day -1 during the last 30 days, resulting in subsequent increase in overall COD removal and biogas production, up to maximum values of 85% and 29 L biogas L reactor -1 day -1 , respectively. Methane content of the biogas produced from the anaerobic digestion ranged between 65% and 74%.

Anaerobic treatment of olive mill wastewater and piggery effluents fermented with Candida tropicalis

Energy Technology Data Exchange (ETDEWEB)

Martinez-Garcia, Gregorio [Department of Chemical and Process Engineering, University of Sheffield, S1 3JD Sheffield (United Kingdom); Johnson, Anbu Clemensis, E-mail: acj265@yahoo.com [Department of Chemical and Process Engineering, University of Sheffield, S1 3JD Sheffield (United Kingdom)] [School of Environmental Engineering, Universiti Malaysia Perlis, 02600 Jejawi, Perlis (Malaysia); Bachmann, Robert T. [Department of Chemical and Process Engineering, University of Sheffield, S1 3JD Sheffield (United Kingdom)] [Malaysian Institute of Chemical and Bioengineering Technology, Universiti Kuala Lumpur, 1988 Vendor City, 7800 Taboh Naning, Alor Gajah, Melaka (Malaysia); Williams, Ceri J. [Yorkshire-Forward, Victoria House, Victoria Place, LS11 5AE Leeds (United Kingdom); Burgoyne, Andrea; Edyvean, Robert G.J. [Department of Chemical and Process Engineering, University of Sheffield, S1 3JD Sheffield (United Kingdom)

2009-05-30

Olive mill wastewater (OMW) contains high concentrations of phenolic compounds that are inhibitory to many microorganisms making it difficult to treat biologically prior to discharge in waterways. The total mono-cyclic phenol reduction in OMW in this study was carried out by aerobic pre-treatment using the yeast Candida tropicalis in a 18 L batch reactor at 30 deg. C for 12 days followed by anaerobic co-digestion. A COD removal of 62% and a reduction in the total mono-cyclic phenol content by 51% of the mixture was achieved in the aerobic pre-treatment. Pig slurry was added as co-substrate to supplement the low nitrogen levels in the olive mill wastewater. Subsequent anaerobic treatment was carried out in a 20 L fixed-bed reactor at 37 deg. C and HRT between 11 and 45 days. After a long start-up period, the OLR was increased from 1.25 to 5 kg COD m{sup -3} day{sup -1} during the last 30 days, resulting in subsequent increase in overall COD removal and biogas production, up to maximum values of 85% and 29 L{sub biogas}L{sub reactor}{sup -1}day{sup -1}, respectively. Methane content of the biogas produced from the anaerobic digestion ranged between 65% and 74%.

[Separate factors influencing the interaction of carbohydrate- containing liposomes with galactose-specific lectins].

Science.gov (United States)

Dvorkin, V M; Vidershaĭn, G Ia

1984-11-01

Some natural (Gal-Cer, Lac-Cer, desyalylated gangliosides) and synthetic (HMGal) glycolipids differing in the length of the bridge linking the terminal galactose with the hydrophobic moiety were incorporated into the liposome membranes. The precipitation of the thus obtained vesicles induced by galactose-specific lectin RCA was studied. It was shown that when the amount of the glycolipids used for the incorporation into the liposomes (1 mol. %) was the same, the vesicles with HMGal or Gal-Cer incorporated into them did not precipitate in the presence of lectin, whereas the liposomes with incorporated Lac-Cer or desyalylated gangliosides did precipitate. It was thus concluded that in order for galactose-containing liposomes precipitation by lectin RCA1 to be induced, galactose should be separated from the liposome membrane with a distance not less than 7 A. The nature of lectin-induced nonspecific precipitation of ganglioside-containing liposomes, ganglioside mycelles and cardiolipin-lecithine liposomes containing lactosylceramide was investigated. Some nonspecific ionic interactions of negatively charged liposomes and ganglioside mycelles with lectin were observed, which disappeared with a rise in the NaCl concentration up to 150-200 mM.

Improve the Recovery of Fermentable Sugar from Rice Straw by Sonication and Its Mathematical Modeling

Science.gov (United States)

Bhattacharyya, Saurav; Dutta, Somenath; Datta, Sidhartha; Bhattacharjee, Chiranjib

2012-08-01

Rice straw is waste renewable agricultural biomass, which contains sufficient amount of fermentable sugars like glucose, galactose fructose, xylose etc. These sugars can be treated with fermentation pathway to produce ethanol. Hydrolysis of pretreated rice straw in dilute sulfuric acid was investigated at different acid concentrations (0.25-0.75 % w/v), and sonication was carried out to improve the extent of sugar extraction. The current work examines the effect of sonication on extraction of total reducing sugar (TRS) and an empirical mathematical model has been established to predict it. Effects of various operating variables of sonication, including amplitude (60-100 %), cycle (0.6-1.0), treatment time (0-15 min) have been analyzed for each acid concentration. Observation shows that on optimization of the sonication conditions (100 % amplitude, 0.8 cycle and 10 min) around 90 % improvement of TRS extraction occurs at 0.5 % (w/v) acid concentration.

Energy recovery from wastewater treatment plants through sludge anaerobic digestion: effect of low-organic-content sludge.

Science.gov (United States)

Zhang, Yuyao; Li, Huan

2017-09-18

During anaerobic digestion, low-organic-content sludge sometimes is used as feedstock, resulting in deteriorated digestion performance. The operational experience of conventional anaerobic digestion cannot be applied to this situation. To investigate the feature of low-organic-content sludge digestion and explain its intrinsic mechanism, batch experiments were conducted using designed feedstock having volatile solids (VS) contents that were 30-64% of total solids (TS). The results showed that the accumulative biogas yield declined proportionally from 173.7 to 64.8 ml/g VS added and organic removal rate decreased from 34.8 to 11.8% with decreasing VS/TS in the substrate. The oligotrophic environment resulting from low-organic-content substrates led to decreased microbial activity and a switch from butyric fermentation to propionic fermentation. A first-order model described the biogas production from the batch experiments very well, and the degradation coefficient decreased from 0.159 to 0.069 day -1 , exhibiting a positive relation with organic content in substrate. The results observed here corroborated with data from published literature on anaerobic digestion of low-organic-content sludge and showed that it may not be feasible to recover energy from sludge with an organic content lower than 50% through mono digestion.

Pancreatic protective and hypoglycemic effects of Vitex agnus-castus L. fruit hydroalcoholic extract in D-galactose-induced aging mouse model.

Science.gov (United States)

Ahangarpour, Akram; Oroojan, Ali Akbar; Khorsandi, Layasadat; Najimi, Seyedeh Asma

2017-04-01

D-galactose induces pancreatic disorder along with aging mouse model. Vitex agnus-castus (VAC) has potential pancreatic protective effect. Hence, this study was designed to evaluate the hypoglycemic and pancreas protective effects of VAC hydroalcoholic extract in D-galactose-induced aging female mice. In the present experimental study, 72 adult female Naval Medical Research Institute (NMRI) mice (weighing 30-35 g) were divided into 6 groups of control, VAC hydroalcoholic extract, D-galactose, D-galactose + VAC hydroalcoholic extract, aged, aged + VAC hydroalcoholic extract. The aged model was prepared by subcutaneous injection of D-galactose for 45 days and, VAC hydroalcoholic extract was gavaged twice a day in the last 7 days. 24 h after the last drug and extract administrations, serum samples and pancreatic tissues were removed to evaluate experimental and histological determinations. Serum glucose level decreased in VAC, D-galactose and, aged-treated groups compared to the control ( P < 0.05). Insulin level increased in VAC and decreased in D-galactose and aged VAC-treated mice compared to the control ( P < 0.05). Homeostasis model assessment-estimated insulin resistance (HOMA-IR) increased in D-galactose, aging, and VAC hydroalcoholic extract groups ( P < 0.05) and, administration of VAC hydroalcoholic extract improved HOMA-IR in D-galactose and aging treated animals. Despite the size of pancreatic islets decreased in aged and D-galactose groups, VAC administration recovered it. Present data showed that VAC hydroalcoholic extract has hypoglycemic and pancreatic protective effects in natural aged and aging model mice.

Microbial culture selection for bio-hydrogen production from waste ground wheat by dark fermentation

Energy Technology Data Exchange (ETDEWEB)

Argun, Hidayet; Kargi, Fikret; Kapdan, Ilgi K. [Department of Environmental Engineering, Dokuz Eylul University, Buca, Izmir (Turkey)

2009-03-15

Hydrogen formation performances of different anaerobic bacteria were investigated in batch dark fermentation of waste wheat powder solution (WPS). Serum bottles containing wheat powder were inoculated with pure cultures of Clostridium acetobutylicum (CAB), Clostridium butyricum (CB), Enterobacter aerogenes (EA), heat-treated anaerobic sludge (ANS) and a mixture of those cultures (MIX). Cumulative hydrogen formation (CHF), hydrogen yield (HY) and specific hydrogen production rate (SHPR) were determined for every culture. The heat-treated anaerobic sludge was found to be the most effective culture with a cumulative hydrogen formation of 560 ml, hydrogen yield of 223 ml H{sub 2} g{sup -1} starch and a specific hydrogen production rate of 32.1 ml H{sub 2} g{sup -1} h{sup -1}. (author)

UDP-galactose: ceramide galactosyltransferase is a class I integral membrane protein of the endoplasmic reticulum

NARCIS (Netherlands)

Sprong, H.; Kruithof, B.; Leijendekker, R.L.; Slot, J.W.; van Meer, G.; van der Sluijs, P.

1998-01-01

UDP-galactose:ceramide galactosyltransferase (CGalT) transfers UDP-galactose to ceramide to form the glycosphingolipid galactosylceramide. Galactosylceramide is the major constituent of myelin and is also highly enriched in many epithelial cells, where it is thought to play an important role in

Thermophilic Alkaline Fermentation Followed by Mesophilic Anaerobic Digestion for Efficient Hydrogen and Methane Production from Waste-Activated Sludge: Dynamics of Bacterial Pathogens as Revealed by the Combination of Metagenomic and Quantitative PCR Analyses.

Science.gov (United States)

Wan, Jingjing; Jing, Yuhang; Rao, Yue; Zhang, Shicheng; Luo, Gang

2018-03-15

Thermophilic alkaline fermentation followed by mesophilic anaerobic digestion (TM) for hydrogen and methane production from waste-activated sludge (WAS) was investigated. The TM process was also compared to a process with mesophilic alkaline fermentation followed by a mesophilic anaerobic digestion (MM) and one-stage mesophilic anaerobic digestion (M) process. The results showed that both hydrogen yield (74.5 ml H 2 /g volatile solids [VS]) and methane yield (150.7 ml CH 4 /g VS) in the TM process were higher than those (6.7 ml H 2 /g VS and 127.8 ml CH 4 /g VS, respectively) in the MM process. The lowest methane yield (101.2 ml CH 4 /g VS) was obtained with the M process. Taxonomic results obtained from metagenomic analysis showed that different microbial community compositions were established in the hydrogen reactors of the TM and MM processes, which also significantly changed the microbial community compositions in the following methane reactors compared to that with the M process. The dynamics of bacterial pathogens were also evaluated. For the TM process, the reduced diversity and total abundance of bacterial pathogens in WAS were observed in the hydrogen reactor and were further reduced in the methane reactor, as revealed by metagenomic analysis. The results also showed not all bacterial pathogens were reduced in the reactors. For example, Collinsella aerofaciens was enriched in the hydrogen reactor, which was also confirmed by quantitative PCR (qPCR) analysis. The study further showed that qPCR was more sensitive for detecting bacterial pathogens than metagenomic analysis. Although there were some differences in the relative abundances of bacterial pathogens calculated by metagenomic and qPCR approaches, both approaches demonstrated that the TM process was more efficient for the removal of bacterial pathogens than the MM and M processes. IMPORTANCE This study developed an efficient process for bioenergy (H 2 and CH 4 ) production from WAS and elucidates the

Anaerobic hydrogen production from unhydrolyzed mushroom farm waste by indigenous microbiota.

Science.gov (United States)

Lin, Chiu-Yue; Lay, Chyi-How; Sung, I-Yuan; Sen, Biswarup; Chen, Chin-Chao

2017-10-01

The cultivation of mushrooms generates large amounts of waste polypropylene bags stuffed with wood flour and bacterial nutrients that makes the mushroom waste (MW) a potential feedstock for anaerobic bioH 2 fermentation. MW indigenous bacteria were enriched using thermophilic temperature (55°C) for use as the seed inoculum without any external seeding. The peak hydrogen production rate (6.84 mmol H 2 /L-d) was obtained with cultivation pH 8 and substrate concentration of 60 g MW/L in batch fermentation. Hydrogen production yield (HY) is pH and substrate concentration dependent with an HY decline occurring at pH and substrate concentration increasing from pH 8 to 10 and 60 to 80 g MW/L, respectively. The fermentation bioH 2 production from MW is in an acetate-type metabolic path. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

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...

Vascular filtration function in galactose-fed versus diabetic rats: The role of polyol pathway activity

Energy Technology Data Exchange (ETDEWEB)

Pugliese, G.; Tilton, R.G.; Speedy, A.; Chang, K.; Province, M.A.; Kilo, C.; Williamson, J.R. (Washington Univ. School of Medicine, St Louis, MO (USA))

1990-07-01

These studies were undertaken to assess the effects of increased galactose (v increased glucose) metabolism via the polyol pathway on vascular filtration function in the kidneys, eyes, nerves, and aorta. Quantitative radiolabeled tracer techniques were used to assess glomerular filtration rate (GFR) and regional tissue vascular clearance of plasma 131I-bovine serum albumin (BSA) in five groups of male Sprague-Dawley rats: nondiabetic controls, streptozotocin-diabetic rats, nondiabetic rats fed a 50% galactose diet, diabetic rats treated with sorbinil (an aldose reductase inhibitor), and galactose-fed rats treated with sorbinil. Sorbinil was added to the diet to provide a daily dose of approximately .2 mmol/kg body weight. After 2 months of diabetes or galactose ingestion, albumin clearance was increased twofold to fourfold in the eye (anterior uvea, choroid, and retina), sciatic nerve, aorta, and kidney; GFR was increased approximately twofold and urinary excretion of endogenous albumin and IgG were increased approximately 10-fold. Sorbinil treatment markedly reduced or completely prevented all of these changes in galactose-fed, as well as in diabetic rats. These observations support the hypothesis that increased metabolism of glucose via the sorbitol pathway is of central importance in mediating virtually all of the early changes in vascular filtration function associated with diabetes in the kidney, as well as in the eyes, nerves, and aorta. On the other hand, renal hypertrophy in diabetic rats and polyuria, hyperphagia, and impaired weight gain in galactose-fed and in diabetic rats were unaffected by sorbinil and therefore are unlikely to be mediated by increased polyol metabolism.

Vascular filtration function in galactose-fed versus diabetic rats: The role of polyol pathway activity

International Nuclear Information System (INIS)

Pugliese, G.; Tilton, R.G.; Speedy, A.; Chang, K.; Province, M.A.; Kilo, C.; Williamson, J.R.

1990-01-01

These studies were undertaken to assess the effects of increased galactose (v increased glucose) metabolism via the polyol pathway on vascular filtration function in the kidneys, eyes, nerves, and aorta. Quantitative radiolabeled tracer techniques were used to assess glomerular filtration rate (GFR) and regional tissue vascular clearance of plasma 131I-bovine serum albumin (BSA) in five groups of male Sprague-Dawley rats: nondiabetic controls, streptozotocin-diabetic rats, nondiabetic rats fed a 50% galactose diet, diabetic rats treated with sorbinil (an aldose reductase inhibitor), and galactose-fed rats treated with sorbinil. Sorbinil was added to the diet to provide a daily dose of approximately .2 mmol/kg body weight. After 2 months of diabetes or galactose ingestion, albumin clearance was increased twofold to fourfold in the eye (anterior uvea, choroid, and retina), sciatic nerve, aorta, and kidney; GFR was increased approximately twofold and urinary excretion of endogenous albumin and IgG were increased approximately 10-fold. Sorbinil treatment markedly reduced or completely prevented all of these changes in galactose-fed, as well as in diabetic rats. These observations support the hypothesis that increased metabolism of glucose via the sorbitol pathway is of central importance in mediating virtually all of the early changes in vascular filtration function associated with diabetes in the kidney, as well as in the eyes, nerves, and aorta. On the other hand, renal hypertrophy in diabetic rats and polyuria, hyperphagia, and impaired weight gain in galactose-fed and in diabetic rats were unaffected by sorbinil and therefore are unlikely to be mediated by increased polyol metabolism

Fermentation of hexoses to ethanol

Energy Technology Data Exchange (ETDEWEB)

Gustafsson, Lena [Goeteborg Univ. (Sweden). Dept. of General and Marine Microbiology]|[Chalmers Univ. of Technology, Goeteborg (Sweden). Dept of Chemical Reaction Engineering

2000-06-01

The Goals of the project has been: to increase the ethanol yield by reducing the by-product formation, primarily biomass and glycerol, and to prevent stuck fermentations, i.e. to maintain a high ethanol production rate simultaneously with a high ethanol yield. The studies have been performed both in defined laboratory media and in a mixture of wood- and wheat hydrolysates. The yeast strains used have been both industrial strains of bakers yeast, Saccharomyces cerevisiae, and haploid laboratory strains. The Relevance of these studies with respect to production of ethanol to be used as fuel is explained by: With the traditional process design used today, it is very difficult to reach a yield of more than 90 % of the theoretical maximal value of ethanol based on fermented hexose. During 'normal' growth and fermentation conditions in either anaerobic batch or chemostat cultures, substrate is lost as biomass and glycerol in the range of 8 to 11 % and 6 to 11 % of the substrate consumed (kg/kg). It is essential to reduce these by-products. Traditional processes are mostly batch processes, in which there is a risk that the biocatalyst, i.e. the yeast, may become inactivated. If for example yeast biomass production is avoided by use of non-growing systems, the ethanol production rate is instantaneously reduced by at least 50%. Unfortunately, even if yeast biomass production is not avoided on purpose, it is well known that stuck fermentations caused by cell death is a problem in large scale yeast processes. The main reason for stuck fermentations is nutrient imbalances. For a good process economy, it is necessary to ensure process accessibility, i.e. to maintain a high and reproducible production rate. This will both considerably reduce the necessary total volume of the fermentors (and thereby the investment costs), and moreover minimize undesirable product fall-out.

MASS TRANSFER IN FERMENTATION PROCESSES

Directory of Open Access Journals (Sweden)

A. Shevchenko

2018-04-01

Full Text Available The peculiarities of anaerobic fermentation processes with the accumulation of dissolved ethyl alcohol and carbon dioxide in the culture media are considered in the article.The solubility of CO2 is limited by the state of saturation in accordance with Henry’s law. This, with all else being equal, limits the mass transfer on the interface surface of yeast cells and the liquid phase of the medium. A phenomenological model of the media restoration technologies based on the unsaturation index on СО2 is developed. It is shown that this restoration in the existing technologies of fermentation of sugar-rich media occurs, to a limited extent, in self-organized flow circuits, with variable values of temperatures and hydrostatic pressures, due to the creation of unsaturated local zones.It is shown that increasing the height of the media in isovolumetric apparatuses leads to an increase in the levels of flow circuits organization and to the improvement of the desaturation and saturation modes of the liquid phase and intensification of mass transfer processes. Among the deterministic principles of restoring the saturation possibilities of the media, there are forced variables of pressures with time pauses on their lower and upper levels. In such cases, the possibilities of short-term intensive desaturations in full media volumes, the restoration of their saturation perception of CO2, and the activation of fermentation processes are achieved. This direction is technically feasible for active industrial equipment.The cumulative effect of the action of variable pressures and temperatures corresponds to the superposition principle, but at the final stages of fermentation, the pressure and temperature values are leveled, so the restoration of the unsaturation state slows down to the level of the bacteriostatic effect. The possibility of eliminating the disadvantages of the final stage of fermentation by means of programmable variable pressures is shown

Microbial ecology of anaerobic digesters: the key players of anaerobiosis.

Science.gov (United States)

Ali Shah, Fayyaz; Mahmood, Qaisar; Maroof Shah, Mohammad; Pervez, Arshid; Ahmad Asad, Saeed

2014-01-01

Anaerobic digestion is the method of wastes treatment aimed at a reduction of their hazardous effects on the biosphere. The mutualistic behavior of various anaerobic microorganisms results in the decomposition of complex organic substances into simple, chemically stabilized compounds, mainly methane and CO2. The conversions of complex organic compounds to CH4 and CO2 are possible due to the cooperation of four different groups of microorganisms, that is, fermentative, syntrophic, acetogenic, and methanogenic bacteria. Microbes adopt various pathways to evade from the unfavorable conditions in the anaerobic digester like competition between sulfate reducing bacteria (SRB) and methane forming bacteria for the same substrate. Methanosarcina are able to use both acetoclastic and hydrogenotrophic pathways for methane production. This review highlights the cellulosic microorganisms, structure of cellulose, inoculum to substrate ratio, and source of inoculum and its effect on methanogenesis. The molecular techniques such as DGGE (denaturing gradient gel electrophoresis) utilized for dynamic changes in microbial communities and FISH (fluorescent in situ hybridization) that deal with taxonomy and interaction and distribution of tropic groups used are also discussed.

Microbial Ecology of Anaerobic Digesters: The Key Players of Anaerobiosis

Science.gov (United States)

Ali Shah, Fayyaz; Mahmood, Qaisar; Maroof Shah, Mohammad; Pervez, Arshid; Ahmad Asad, Saeed

2014-01-01

Anaerobic digestion is the method of wastes treatment aimed at a reduction of their hazardous effects on the biosphere. The mutualistic behavior of various anaerobic microorganisms results in the decomposition of complex organic substances into simple, chemically stabilized compounds, mainly methane and CO2. The conversions of complex organic compounds to CH4 and CO2 are possible due to the cooperation of four different groups of microorganisms, that is, fermentative, syntrophic, acetogenic, and methanogenic bacteria. Microbes adopt various pathways to evade from the unfavorable conditions in the anaerobic digester like competition between sulfate reducing bacteria (SRB) and methane forming bacteria for the same substrate. Methanosarcina are able to use both acetoclastic and hydrogenotrophic pathways for methane production. This review highlights the cellulosic microorganisms, structure of cellulose, inoculum to substrate ratio, and source of inoculum and its effect on methanogenesis. The molecular techniques such as DGGE (denaturing gradient gel electrophoresis) utilized for dynamic changes in microbial communities and FISH (fluorescent in situ hybridization) that deal with taxonomy and interaction and distribution of tropic groups used are also discussed. PMID:24701142

Intensification of anaerobic digestion efficiency with use of mechanical excess sludge disintegration in the context of increased energy production in wastewater treatment plants

Directory of Open Access Journals (Sweden)

Żubrowska-Sudoł Monika

2017-01-01

Full Text Available The main goal of the study was to evaluate the effects of mechanical sludge disintegration for enhancing full scale anaerobic digestion of municipal sludge. Batch disintegration tests and lab dewatering tests were also performed aiming at determining the release of organic compounds and assessing the impact of disintegration of excess sludge before the fermentation process of mixed sludge on the dewaterability of post-fermented sludge, respectively. In the study a disc disintegrator driven by a motor with a power of 30 kW, revolutions n = 2950 rpm has been used. It was shown that with increase of energy consumed in the disintegration, the increased amounts of organic compounds were released from the sludge. It was also documented that the introduction of the excess sludge disintegration prior to fermentation tank, resulted in a significant increase in biogas production (by an average of 33.9% and in increase in volatile total solids reduction in the fermented sludge (by an average of 22.7%. Moreover, the obtained results indicate the possibility of obtaining a higher degree of sludge dewatering, which was subjected to anaerobic stabilization with using disintegrated excess sludge.

Intensification of anaerobic digestion efficiency with use of mechanical excess sludge disintegration in the context of increased energy production in wastewater treatment plants

Science.gov (United States)

Żubrowska-Sudoł, Monika; Podedworna, Jolanta; Bisak, Agnieszka; Sytek-Szmeichel, Katarzyna; Krawczyk, Piotr; Garlicka, Agnieszka

2017-11-01

The main goal of the study was to evaluate the effects of mechanical sludge disintegration for enhancing full scale anaerobic digestion of municipal sludge. Batch disintegration tests and lab dewatering tests were also performed aiming at determining the release of organic compounds and assessing the impact of disintegration of excess sludge before the fermentation process of mixed sludge on the dewaterability of post-fermented sludge, respectively. In the study a disc disintegrator driven by a motor with a power of 30 kW, revolutions n = 2950 rpm has been used. It was shown that with increase of energy consumed in the disintegration, the increased amounts of organic compounds were released from the sludge. It was also documented that the introduction of the excess sludge disintegration prior to fermentation tank, resulted in a significant increase in biogas production (by an average of 33.9%) and in increase in volatile total solids reduction in the fermented sludge (by an average of 22.7%). Moreover, the obtained results indicate the possibility of obtaining a higher degree of sludge dewatering, which was subjected to anaerobic stabilization with using disintegrated excess sludge.

Saccharomyces cerevisiae in the Production of Fermented Beverages

Directory of Open Access Journals (Sweden)

Graeme M Walker

2016-11-01

Full Text Available Alcoholic beverages are produced following the fermentation of sugars by yeasts, mainly (but not exclusively strains of the species, Saccharomyces cerevisiae. The sugary starting materials may emanate from cereal starches (which require enzymatic pre-hydrolysis in the case of beers and whiskies, sucrose-rich plants (molasses or sugar juice from sugarcane in the case of rums, or from fruits (which do not require pre-hydrolysis in the case of wines and brandies. In the presence of sugars, together with other essential nutrients such as amino acids, minerals and vitamins, S. cerevisiae will conduct fermentative metabolism to ethanol and carbon dioxide (as the primary fermentation metabolites as the cells strive to make energy and regenerate the coenzyme NAD+ under anaerobic conditions. Yeasts will also produce numerous secondary metabolites which act as important beverage flavour congeners, including higher alcohols, esters, carbonyls and sulphur compounds. These are very important in dictating the final flavour and aroma characteristics of beverages such as beer and wine, but also in distilled beverages such as whisky, rum and brandy. Therefore, yeasts are of vital importance in providing the alcohol content and the sensory profiles of such beverages. This Introductory Chapter reviews, in general, the growth, physiology and metabolism of S. cerevisiae in alcoholic beverage fermentations.

Cleaner production of citric acid by recycling its extraction wastewater treated with anaerobic digestion and electrodialysis in an integrated citric acid-methane production process.

Science.gov (United States)

Xu, Jian; Su, Xian-Feng; Bao, Jia-Wei; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

2015-01-01

To solve the pollution problem of extraction wastewater in citric acid production, an integrated citric acid-methane production process was proposed. Extraction wastewater was treated through anaerobic digestion and the anaerobic digestion effluent (ADE) was recycled for the next batch of citric acid fermentation, thus eliminating wastewater discharge and reducing water consumption. Excessive Na(+) contained in ADE could significantly inhibit citric acid fermentation in recycling and was removed by electrodialysis in this paper. Electrodialysis performance was improved after pretreatment of ADE with air stripping and activated carbon adsorption to remove precipitable metal ions and pigments. Moreover, the concentrate water was recycled and mixed with feed to improve the water recovery rate above 95% in electrodialysis treatment, while the dilute water was collected for citric acid fermentation. The removal rate of Na(+) in ADE was above 95% and the citric acid production was even higher than that with tap water. Copyright © 2015 Elsevier Ltd. All rights reserved.

Characterization of Eubacterium coprostanoligenes sp. nov., a cholesterol-reducing anaerobe.

Science.gov (United States)

Freier, T A; Beitz, D C; Li, L; Hartman, P A

1994-01-01

A small, anaerobic, gram-positive coccobacillus that reduces cholesterol to coprostanol was isolated from a hog sewage lagoon. This isolate, strain HLT (T = type strain) does not require cholesterol for growth, but it requires lecithin and has phospholipase activity. Much acid is produced by the fermentation of amygdalin, lactose, and salicin. Arabinose, cellobiose, fructose, glucose, mannose, and melibiose are fermented weakly. Acetic, formic, and succinic acids are produced, as is hydrogen. The isolate does not reduce nitrate, produce indole, or hydrolyze starch and gelatin. Esculin is hydrolyzed. The properties of strain HLT are most similar to those of members of the genus Eubacterium. Because strain HL (= ATCC 51222) has unique morphological and physiological properties, we propose that it should be the type strain of a new species in the genus Eubacterium, Eubacterium coprostanoligenes.

Conversion of Corn Stover Hydrolysates to Acids: Comparison Between Clostridium carboxidivorans P7 and Microbial Communities Developed from Lake Sediment and an Anaerobic Digester

Energy Technology Data Exchange (ETDEWEB)

Chen, Xiaowen [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Tucker, Melvin P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Xia, Chunjie [Southern Illinois University; Kumar, Aditi [Carbondale Community High School; Liang, Yanna [Southern Illinois University

2017-01-18

Anaerobic fermentation is an environmentally sustainable technology for converting a variety of feedstocks to biofuels and bioproducts. Considering the complex nature of lignocellulosic hydrolysates, we aimed to investigate product formation from corn stover hydrolysates by using microbial communities under anaerobic conditions. A community developed from lake sediment was able to produce lactic acid from only glucose in the raw or overlimed hydrolysates. Another community from an anaerobic digester, however, was capable of using all hexose and pentose sugars in the raw and undetoxified hydrolysates and released lactic acid at 26.76 g/L. A pure acetogen, Clostridium carboxidivorans P7, was able to grow on the raw and overlimed hydrolysates, too. But the consumption of sugars was minimal and the total released acid concentrations were less than 2 g/L. Next generation sequencing of the enriched community derived from the anaerobic digester revealed the presence of Lactobacillus strains. The predominant species were Lactobacillus parafarraginis (72.6%) and L. buchneri (13.4%). Product titer from using this enriched community can be further enhanced by cultivating at fed-batch or continuous fermentation modes. Results from this study widened the door for producing valuable products from lignocellulosic feedstocks through using mixed cultures.

Comparative analysis of microbial community of novel lactic acid fermentation inoculated with different undefined mixed cultures.

Science.gov (United States)

Liang, Shaobo; Gliniewicz, Karol; Mendes-Soares, Helena; Settles, Matthew L; Forney, Larry J; Coats, Erik R; McDonald, Armando G

2015-03-01

Three undefined mixed cultures (activated sludge) from different municipal wastewater treatment plants were used as seeds in a novel lactic acid fermentation process fed with potato peel waste (PPW). Anaerobic sequencing batch fermenters were run under identical conditions to produce predominantly lactic acid. Illumina sequencing was used to examine the 16S rRNA genes of bacteria in the three seeds and fermenters. Results showed that the structure of microbial communities of three seeds were different. All three fermentation products had unique community structures that were dominated (>96%) by species of the genus Lactobacillus, while members of this genus constituted undefined mixed cultures were robust and resilient, which provided engineering prospects for the microbial utilization of carbohydrate wastes to produce lactic acid. Copyright © 2014 Elsevier Ltd. All rights reserved.

Oral D-galactose supplementation in PGM1-CDG

NARCIS (Netherlands)

Wong, S.Y.W.; Gadomski, T.; Scherpenzeel, M. van; Honzik, T.; Hansikova, H.; Holmefjord, K.S.B.; Mork, M.; Bowling, F.; Sykut-Cegielska, J.; Koch, D.; Hertecant, J.; Preston, G.; Jaeken, J.; Peeters, N.; Perez, S.; Nguyen, D.D.; Crivelly, K.; Emmerzaal, T.L.; Gibson, K.M.; Raymond, K.; Bakar, N. Abu; Foulquier, F.; Poschet, G.; Ackermann, A.M.; He, M.; Lefeber, D.J.; Thiel, C.; Kozicz, L.T.; Morava, E.

2017-01-01

PurposePhosphoglucomutase-1 deficiency is a subtype of congenital disorders of glycosylation (PGM1-CDG). Previous casereports in PGM1-CDG patients receiving oral D-galactose (D-gal) showed clinical improvement. So far no systematic in vitro and clinical studies have assessed safety and benefits of

Biotransformation of 5-hydroxymethylfurfural (HMF) by Scheffersomyces stipitis during ethanol fermentation of hydrolysate of the seaweed Gelidium amansii.

Science.gov (United States)

Ra, Chae Hun; Jeong, Gwi-Taek; Shin, Myung Kyo; Kim, Sung-Koo

2013-07-01

The seaweed, Gelidium amansii, was fermented to produce bioethanol. Optimal pretreatment condition was determined as 94 mM H2SO4 and 10% (w/v) seaweed slurry at 121°C for 60 min. The mono sugars of 43.5 g/L with 57.4% of conversion from total carbohydrate of 75.8 g/L with G. amansii slurry 100g dcw/L were obtained by thermal acid hydrolysis pretreatment and enzymatic saccharification. G. amansii hydrolysate was used as the substrate for ethanol production by separate hydrolysis and fermentation (SHF). The ethanol concentration of 20.5 g/L was produced by Scheffersomyces stipitis KCTC 7228. The effect of HMF on ethanol production by S. stipitis KCTC 7228 was evaluated and 5-hydroxymethylfurfural (HMF) was converted to 2,5-bis-hydroxymethylfuran. The accumulated 2,5-bis-hydroxymethylfuran in the medium did not affect galactose and glucose uptakes and ethanol production. Biotransformation of HMF to less inhibitory compounds by S. stipitis KCTC 7228 could enhance overall fermentation yields of seaweed hydrolysates to ethanol. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ovotoxic effects of galactose involve attenuation of follicle-stimulating hormone bioactivity and up-regulation of granulosa cell p53 expression.

Directory of Open Access Journals (Sweden)

Sayani Banerjee

Full Text Available Clinical evidence suggests an association between galactosaemia and premature ovarian insufficiency (POI; however, the mechanism still remains unresolved. Experimental galactose toxicity in rats produces an array of ovarian dysfunction including ovarian development with deficient follicular reserve and follicular resistance to gonadotrophins that characterize the basic tenets of human POI. The present investigation explores if galactose toxicity in rats attenuates the bioactivity of gonadotrophins or interferes with their receptor competency, and accelerates the rate of follicular atresia. Pregnant rats were fed isocaloric food-pellets supplemented with or without 35% D-galactose from day-3 of gestation and continuing through weaning of the litters. The 35-day old female litters were autopsied. Serum galactose-binding capacity, galactosyltransferase (GalTase activity, and bioactivity of FSH and LH together with their receptor competency were assessed. Ovarian follicular atresia was evaluated in situ by TUNEL. The in vitro effects of galactose were studied in isolated whole follicles in respect of generation of reactive oxygen species (ROS and expression of caspase 3, and in isolated granulosa cells in respect of mitochondrial membrane potential, expression of p53, and apoptosis. The rats prenatally exposed to galactose exhibited significantly decreased serum GalTase activity and greater degree of galactose-incorporation capacity of sera proteins. LH biopotency and LH-FSH receptor competency were comparable between the control and study population, but the latter group showed significantly attenuated FSH bioactivity and increased rate of follicular atresia. In culture, galactose increased follicular generation of ROS and expression of caspase 3. In isolated granulosa cells, galactose disrupted mitochondrial membrane potential, stimulated p53 expression, and induced apoptosis in vitro; however co-treatment with either FSH or estradiol

Synthesis and Biophysical Investigations of Oligonucleotides Containing Galactose-Modified DNA, LNA and 2'-Amino-LNA Monomers

DEFF Research Database (Denmark)

Ries, Annika; Kumar, Rajesh; Lou, Chenguang

2016-01-01

Galactose-modified thymidine, LNA-T and 2'-amino-LNA-T nucleosides were synthesized, converted into the corresponding phosphoramidite derivatives and introduced into short oligonucleotides. Compared to the unmodified control strands, the galactose-modified oligonucleotides in general, and the N2'...

Estudo da fermentação alcoólica de soluções diluídas de diferentes açucares utilizando microcalorimetria de fluxo Study of the alcoholic fermentation of sugars diluted solutions through flow microcalorimetry

Directory of Open Access Journals (Sweden)

Pedro L. O. Volpe

1997-10-01

Full Text Available The present study shows that with liquid nitrogen stored inocula of Saccharomyces cerevisiae, and standardized experimental procedure, flow microcalorimetry can be a valuable tool for monitoring in real time the alcoholic fermentation processes on line. The avaliation of cultural conditions contained different carbon sources for alcohol fermentation (sucrose, glucose, fructose, manose, maltose, galactose, molasses, honey and sugar cane and their effects on the heat output recording is discussed. Some examples of diauxic growth is given, where the microcalorimeters serves to detect the temporal order of succession of alternating metabolic pathways.

Limitations of galactose therapy in phosphoglucomutase 1 deficiency

Directory of Open Access Journals (Sweden)

Kristine Nolting

2017-12-01

Conclusions: The results of our study indicate that the current standard dose of galactose might be too low to achieve normal glycosylation in all patients. In addition, growth retardation in PGM1 deficiency is complex and multifactorial. Furthermore, heart rhythm abnormalities must be considered when treating patients with PGM1 deficiency.

Anaerobic biodegradation of spent sulphite liquor in a UASB reactor

DEFF Research Database (Denmark)

Jantsch, T.G.; Angelidaki, Irini; Schmidt, Jens Ejbye

2002-01-01

Anaerobic biodegradation of fermented spent sulphite liquor, SSL, which is produced during the manufacture of sulphite pulp, was investigated. SSL contains a high concentration of lignin products in addition to hemicellulose and has a very high COD load (173 g COD l1). Batch experiments...... ðl dÞ1 and hydraulic retention time from 3.7 to 1.5 days. The biogas productivity was 3 l ðlreactor dÞ1, with a yield of 0.05 l gas ðg VSÞ1. These results suggest that anaerobic digestion in UASB reactors may provide a new alternative for the treatment of SSL to other treatment strategies...... such as incineration. Although the total COD reduction achieved is limited, bioenergy is produced and readily biodegradable matter is removed causing less load on post-treatment installations. 2002 Elsevier Science Ltd. All rights reserved....

Methane Fermentation of Slurry with Chemical and Biological Additive

Directory of Open Access Journals (Sweden)

Anna Smurzyńska

2017-12-01

Full Text Available The problem of proper slurry management is primarily present in intensive livestock production. Industrialized livestock farms generate enormous quantities of manure droppings in a livestock-litter-free system. The traditional management of slurry is made by using it as a fertilizer. Alternative techniques used for neutralizing the detrimental effect of slurry are based on the use of chemical and biological additives, as well as by introducing aerobic environment through aerobic or anaerobic digestion, leading to methane fermentation. In the experiment, cattle manure was used, which came from the Przybroda farm belonging to the University of Life Sciences in Poznan. The aim of the study was to determine the biogas yield of slurry using the chemical and biological additive available on the Polish market. Mesophilic and thermophilic fermentation was used for the indication of the effectiveness of the employed fermentation process. The slurry was supplemented by a biological and chemical additive, i.e. effective microorganisms and – PRP, respectively. The experiment allowed to achieve a higher biogas yield during the use of effective microorganisms.

Antioxidant and Anti-aging Activities of Silybum Marianum Protein Hydrolysate in Mice Treated with D-galactose.

Science.gov (United States)

Zhu, Shu Yun; Jiang, Ning; Tu, Jie; Yang, Jing; Zhou, Yue

2017-09-01

In the present study, we investigated the antioxidant and anti-aging effects of Silybum marianum protein hydrolysate (SMPH) in D-galactose-treated mice. D-galactose (500 mg/kg body weight) was intraperitoneally injected daily for 7 weeks to accelerate aging, and SMPH (400, 800, 1,200 mg/kg body weight, respectively) was simultaneously administered orally. The antioxidant and anti-aging effects of SMPH in the liver and brain were measured by biochemical assays. Transmission electron microscopy (TEM) was performed to study the ultrastructure of liver mitochondri. SMPH decreased triglyceride and cholesterol levels in the D-galactose-treated mice. It significantly elevated the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and total antioxidant capacity (T-AOC), which were suppressed by D-galactose. Monoamine oxidase (MAO) and malondialdehyde (MDA) levels as well as the concentrations of caspase-3 and 8-OHdG in the liver and brain were significantly reduced by SMPH. Moreover, it increased Bcl-2 levels in the liver and brain. Furthermore, SMPH significantly attenuated D-galactose-induced liver mitochondrial dysfunction by improving the activities of Na+-K+-ATPase and Ca2+-Mg2+-ATPase as well as mitochondrial membrane potential (ΔΨm) and fluidity. TEM showed that the degree of liver mitochondrial damage was significantly decreased by SMPH. The results indicated that SMPH protects against D-galactose-induced accelerated aging in mice through its antioxidant and anti-aging activities. Copyright © 2017 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

Detoxification of furfural in Corynebacterium glutamicum under aerobic and anaerobic conditions.

Science.gov (United States)

Tsuge, Yota; Hori, Yoshimi; Kudou, Motonori; Ishii, Jun; Hasunuma, Tomohisa; Kondo, Akihiko

2014-10-01

The toxic fermentation inhibitors in lignocellulosic hydrolysates raise serious problems for the microbial production of fuels and chemicals. Furfural is considered to be one of the most toxic compounds among these inhibitors. Here, we describe the detoxification of furfural in Corynebacterium glutamicum ATCC13032 under both aerobic and anaerobic conditions. Under aerobic culture conditions, furfuryl alcohol and 2-furoic acid were produced as detoxification products of furfural. The ratio of the products varied depending on the initial furfural concentration. Neither furfuryl alcohol nor 2-furoic acid showed any toxic effect on cell growth, and both compounds were determined to be the end products of furfural degradation. Interestingly, unlike under aerobic conditions, most of the furfural was converted to furfuryl alcohol under anaerobic conditions, without affecting the glucose consumption rate. Both the NADH/NAD(+) and NADPH/NADP(+) ratio decreased in the accordance with furfural concentration under both aerobic and anaerobic conditions. These results indicate the presence of a single or multiple endogenous enzymes with broad and high affinity for furfural and co-factors in C. glutamicum ATCC13032.

Bioconversion of D-galactose into D-tagatose by expression of L-arabinose isomerase.

Science.gov (United States)

Roh, H J; Kim, P; Park, Y C; Choi, J H

2000-02-01

D-Tagatose is a potential bulking agent in food as a non-calorific sweetener. To produce D-tagatose from cheaper resources, plasmids harbouring the L-arabinose isomerase gene (araA) from Escherichia coli, Bacillus subtilis and Salmonella typhimurium were constructed because L-arabinose isomerase was suggested previously as an enzyme that mediates the bioconversion of galactose into tagatose as well as that of arabinose to ribulose. The constructed plasmids were named pTC101, pTC105 and pTC106, containing araA from E. coli, B. subtilis and S. typhimurium respectively. In the cultures of recombinant E. coli with pTC101, pTC105 and pTC106, tagatose was produced from galactose in 9.9, 7.1 and 6.9% yields respectively. The enzyme extract of E. coli with the plasmid pTC101 also converted galactose into tagatose with a 96.4% yield.

Molecular galactose-galectin association in neuroblastoma cells: An unconventional tool for qualitative/quantitative screening.

Science.gov (United States)

Pastorino, Fabio; Ponzoni, Mirco; Simone, Giuseppina

2017-05-01

Galectin decorates the cell membrane and forms an extracellular molecular association with galactoside units. Here, galactoside probes have been used to study galectin expression in neuroblastoma cells. The hypothesis behind this investigation has been that the molecular mechanisms by which glycans modulate neural metastatic cells involve a protein-carbohydrate association, galectin-galactose. Preliminary screening to validate the hypothesis has been performed with galactose moieties anchored to beads. The molecular association has been studied by FACS. In vitro experiments reveal the molecular binding preferences of the metastatic neuroblastoma cells. Ex vivo, the galactose probes discriminate healthy tissues. The unconventional assay in microfluidics used in this study displayed results analogous to the above (GI-LI-N cell capture efficiency overcomes IMR-32). At the point of equilibrium of shear and binding forces, the capture yield inside the chamber was measured to 60 ± 4.4% in GI-LI-N versus 40 ± 2.1% in IMR-32. Staining of the fished cells and subsequent conjugation with red beads bearing the galactose also have evidenced that microfluidics can be used to study and quantify the molecular association of galectin-galactose. Most importantly, a crucial insight for obtaining single-cell qualitative/quantitative glycome analysis has been achieved. Finally, the specificity of the assay performed in microfluidics is demonstrated by comparing GI-LI-N fishing efficiency in galactose and fucose environments. The residual adhesion to fucose confirmed the existence of receptors for this glycan and that its eventual unspecific binding (i.e. due to electrostatic interactions) is insignificant compared with the molecular binding. Identification and understanding of this mechanism of discrimination can be relevant for diagnostic monitoring and for producing probes tailored to interfere with galectin activities associated with the malignant phenotype. Besides, the given

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)).

Kinetic modeling of the effect of solids retention time on methanethiol dynamics in anaerobic digestion.

Science.gov (United States)

Zhang, Dian; Strawn, Mary; Novak, John T; Wang, Zhi-Wu

2018-07-01

The highly volatile methanethiol (MT) with an extremely low odor threshold and distinctive putrid smell is often identified as a major odorous compound generated under anaerobic conditions. As an intermediate compound in the course of anaerobic digestion, the extent of MT emission is closely related to the time of anaerobic reaction. In this study, lab-scale anaerobic digesters were operated at solids retention time (SRTs) of 15, 20, 25, 30, 40 and 50 days to investigate the effect of SRT on MT emission. The experimental results demonstrated a bell-shaped curve of MT emission versus SRT with a peak around 20 days SRT. In order to understand this SRT effect, a kinetic model was developed to describe MT production and utilization dynamics in the course of anaerobic digestion and calibrated with the experimental results collected from this study. The model outcome revealed that the high protein content in the feed sludge together with the large maintenance coefficient of MT fermenters are responsible for the peak MT emission emergence in the range of typical SRT used for anaerobic digestion. A further analysis of the kinetic model shows that it can be extensively simplified with reasonable approximation to a form that anaerobic digestion practitioners could easily use to predict the MT and SRT relationship. Copyright © 2018 Elsevier Ltd. All rights reserved.

Assessment of microbial communities associated with fermentative-methanogenic biodegradation of aromatic hydrocarbons in groundwater contaminated with a biodiesel blend (B20).

Science.gov (United States)

Ramos, Débora Toledo; da Silva, Márcio Luís Busi; Nossa, Carlos Wolfgang; Alvarez, Pedro J J; Corseuil, Henry Xavier

2014-09-01

A controlled field experiment was conducted to assess the potential for fermentative-methanogenic biostimulation (by ammonium-acetate injection) to enhance biodegradation of benzene, toluene, ethylbenzene and xylenes (BTEX) as well as polycyclic aromatic hydrocarbons (PAHs) in groundwater contaminated with biodiesel B20 (20:80 v/v soybean biodiesel and diesel). Changes in microbial community structure were assessed by pyrosequencing 16S rRNA analyses. BTEX and PAH removal began 0.7 year following the release, concomitantly with the increase in the relative abundance of Desulfitobacterium and Geobacter spp. (from 5 to 52.7 % and 15.8 to 37.3 % of total Bacteria 16S rRNA, respectively), which are known to anaerobically degrade hydrocarbons. The accumulation of anaerobic metabolites acetate and hydrogen that could hinder the thermodynamic feasibility of BTEX and PAH biotransformations under fermentative/methanogenic conditions was apparently alleviated by the growing predominance of Methanosarcina. This suggests the importance of microbial population shifts that enrich microorganisms capable of interacting syntrophically to enhance the feasibility of fermentative-methanogenic bioremediation of biodiesel blend releases.

Valorization of By-Products from Palm Oil Mills for the Production of Generic Fermentation Media for Microbial Oil Synthesis.

Science.gov (United States)

Tsouko, Erminda; Kachrimanidou, Vasiliki; Dos Santos, Anderson Fragoso; do Nascimento Vitorino Lima, Maria Eduarda; Papanikolaou, Seraphim; de Castro, Aline Machado; Freire, Denise Maria Guimarães; Koutinas, Apostolis A

2017-04-01

This study demonstrates the production of a generic nutrient-rich feedstock using by-product streams from palm oil production that could be used as a substitute for commercial fermentation supplements. Solid-state fermentations of palm kernel cake (PKC) and palm-pressed fiber (PPF) were conducted in tray bioreactors and a rotating drum bioreactor by the fungal strain Aspergillus oryzae for the production of crude enzymes. The production of protease was optimized (319.3 U/g) at an initial moisture content of 55 %, when PKC was used as the sole substrate. The highest free amino nitrogen (FAN) production (5.6 mg/g) obtained via PKC hydrolysis using the crude enzymes produced via solid-state fermentation was achieved at 50 °C. Three initial PKC concentrations (48.7, 73.7, and 98.7 g/L) were tested in hydrolysis experiments, leading to total Kjeldahl nitrogen to FAN conversion yields up to 27.9 %. Sequential solid-state fermentation followed by hydrolysis was carried out in the same rotating drum bioreactor, leading to the production of 136.7 U/g of protease activity during fermentation and 196.5 mg/L of FAN during hydrolysis. Microbial oil production was successfully achieved with the oleaginous yeast strain Lipomyces starkeyi DSM 70296 cultivated on the produced PKC hydrolysate mixed with commercial carbon sources, including glucose, xylose, mannose, galactose, and arabinose.

Directed Evolution Reveals Unexpected Epistatic Interactions That Alter Metabolic Regulation and Enable Anaerobic Xylose Use by Saccharomyces cerevisiae.

Directory of Open Access Journals (Sweden)

Trey K Sato

2016-10-01

Full Text Available The inability of native Saccharomyces cerevisiae to convert xylose from plant biomass into biofuels remains a major challenge for the production of renewable bioenergy. Despite extensive knowledge of the regulatory networks controlling carbon metabolism in yeast, little is known about how to reprogram S. cerevisiae to ferment xylose at rates comparable to glucose. Here we combined genome sequencing, proteomic profiling, and metabolomic analyses to identify and characterize the responsible mutations in a series of evolved strains capable of metabolizing xylose aerobically or anaerobically. We report that rapid xylose conversion by engineered and evolved S. cerevisiae strains depends upon epistatic interactions among genes encoding a xylose reductase (GRE3, a component of MAP Kinase (MAPK signaling (HOG1, a regulator of Protein Kinase A (PKA signaling (IRA2, and a scaffolding protein for mitochondrial iron-sulfur (Fe-S cluster biogenesis (ISU1. Interestingly, the mutation in IRA2 only impacted anaerobic xylose consumption and required the loss of ISU1 function, indicating a previously unknown connection between PKA signaling, Fe-S cluster biogenesis, and anaerobiosis. Proteomic and metabolomic comparisons revealed that the xylose-metabolizing mutant strains exhibit altered metabolic pathways relative to the parental strain when grown in xylose. Further analyses revealed that interacting mutations in HOG1 and ISU1 unexpectedly elevated mitochondrial respiratory proteins and enabled rapid aerobic respiration of xylose and other non-fermentable carbon substrates. Our findings suggest a surprising connection between Fe-S cluster biogenesis and signaling that facilitates aerobic respiration and anaerobic fermentation of xylose, underscoring how much remains unknown about the eukaryotic signaling systems that regulate carbon metabolism.

Directed Evolution Reveals Unexpected Epistatic Interactions That Alter Metabolic Regulation and Enable Anaerobic Xylose Use by Saccharomyces cerevisiae.

Science.gov (United States)

Sato, Trey K; Tremaine, Mary; Parreiras, Lucas S; Hebert, Alexander S; Myers, Kevin S; Higbee, Alan J; Sardi, Maria; McIlwain, Sean J; Ong, Irene M; Breuer, Rebecca J; Avanasi Narasimhan, Ragothaman; McGee, Mick A; Dickinson, Quinn; La Reau, Alex; Xie, Dan; Tian, Mingyuan; Reed, Jennifer L; Zhang, Yaoping; Coon, Joshua J; Hittinger, Chris Todd; Gasch, Audrey P; Landick, Robert

2016-10-01

The inability of native Saccharomyces cerevisiae to convert xylose from plant biomass into biofuels remains a major challenge for the production of renewable bioenergy. Despite extensive knowledge of the regulatory networks controlling carbon metabolism in yeast, little is known about how to reprogram S. cerevisiae to ferment xylose at rates comparable to glucose. Here we combined genome sequencing, proteomic profiling, and metabolomic analyses to identify and characterize the responsible mutations in a series of evolved strains capable of metabolizing xylose aerobically or anaerobically. We report that rapid xylose conversion by engineered and evolved S. cerevisiae strains depends upon epistatic interactions among genes encoding a xylose reductase (GRE3), a component of MAP Kinase (MAPK) signaling (HOG1), a regulator of Protein Kinase A (PKA) signaling (IRA2), and a scaffolding protein for mitochondrial iron-sulfur (Fe-S) cluster biogenesis (ISU1). Interestingly, the mutation in IRA2 only impacted anaerobic xylose consumption and required the loss of ISU1 function, indicating a previously unknown connection between PKA signaling, Fe-S cluster biogenesis, and anaerobiosis. Proteomic and metabolomic comparisons revealed that the xylose-metabolizing mutant strains exhibit altered metabolic pathways relative to the parental strain when grown in xylose. Further analyses revealed that interacting mutations in HOG1 and ISU1 unexpectedly elevated mitochondrial respiratory proteins and enabled rapid aerobic respiration of xylose and other non-fermentable carbon substrates. Our findings suggest a surprising connection between Fe-S cluster biogenesis and signaling that facilitates aerobic respiration and anaerobic fermentation of xylose, underscoring how much remains unknown about the eukaryotic signaling systems that regulate carbon metabolism.

Electricity generation from synthesis gas by microbial processes: CO fermentation and microbial fuel cell technology.

Science.gov (United States)

Kim, Daehee; Chang, In Seop

2009-10-01

A microbiological process was established to harvest electricity from the carbon monoxide (CO). A CO fermenter was enriched with CO as the sole carbon source. The DGGE/DNA sequencing results showed that Acetobacterium spp. were enriched from the anaerobic digester fluid. After the fermenter was operated under continuous mode, the products were then continuously fed to the microbial fuel cell (MFC) to generate electricity. Even though the conversion yield was quite low, this study proved that synthesis gas (syn-gas) can be converted to electricity with the aid of microbes that do not possess the drawbacks of metal catalysts of conventional methods.

Intensification of anaerobic digestion efficiency with use of mechanical excess sludge disintegration in the context of increased energy production in wastewater treatment plants

OpenAIRE

Żubrowska-Sudoł Monika; Podedworna Jolanta; Bisak Agnieszka; Sytek-Szmeichel Katarzyna; Krawczyk Piotr; Garlicka Agnieszka

2017-01-01

The main goal of the study was to evaluate the effects of mechanical sludge disintegration for enhancing full scale anaerobic digestion of municipal sludge. Batch disintegration tests and lab dewatering tests were also performed aiming at determining the release of organic compounds and assessing the impact of disintegration of excess sludge before the fermentation process of mixed sludge on the dewaterability of post-fermented sludge, respectively. In the study a disc disintegrator driven by...

Effects of hydro-alcoholic extract of Vitex agnus-castus fruit on kidney of D-galactose-induced aging model in female mice.

Science.gov (United States)

Oroojan, A A; Ahangarpour, A; Khorsandi, L; Najimi, S A

2016-01-01

The aim of the present study was to evaluate the effect of a hydro-alcoholic extract of Vitex agnus-castus (VAC) fruit on blood urea nitrogen (BUN), creatinine (Cr) and, kidney histology of a female mouse model of D-galactose induced aging. In this experimental study, 72 NMRI mice were divided into 6 groups: control, VAC, D-galactose, D-galactose+VAC, aging, and aging+VAC. D-galactose was injected for 45 days and, VAC extract administered in the last 7 days, twice a day. Serum BUN and Cr levels were not significantly changed in the D-galactose and natural aged animals in comparison to control group. Histological changes such as nuclear pyknosis, proximal cell swelling, infiltration of inflammatory cells, tubular dilatation and, vasodilatation were observed in both D-galactose and natural aged mice. Further, glomerules diameter was decreased in them. Administration of VAC could attenuate the histological alterations. These results indicate that VAC may have beneficial effects on aging and aging related kidney disease.

Continuous dark fermentative hydrogen production by mesophilic microflora: Principles and progress

Energy Technology Data Exchange (ETDEWEB)

Hawkes, Freda R.; Hussy, Ines; Kyazze, Godfrey; Dinsdale, Richard; Hawkes, Dennis L. [School of Applied Sciences, University of Glamorgan, Pontypridd RCT CF37 1DL (United Kingdom)

2007-02-15

Continuous, dark fermentative hydrogen production technology using mixed microflora at mesophilic temperatures may be suitable for commercial development. Clostridial-based cultures from natural sources have been widely used, but more information on the need for heat treatment of inocula and conditions leading to germination and sporulation are required. The amount of nutrients given in the literature vary widely. Hydrogen production is reported to proceed without methane production in the reactor in the pH range 4.5-6.7, with hydraulic retention times optimally between a few hours and 3 days depending on substrate. Higher substrate concentrations should be more energy-efficient but there are product inhibition limitations, for example from unionised butyric acid. Inhibition by H{sub 2} can be reduced by stirring, sparging or extraction through membranes. Of the reactor types investigated, while granules have the best performance with soluble substrate, for particulate feedstock biofilm reactors or continuous stirred tank reactors may be most successful. A second stage is required to utilise the fermentation end products which, when cost-effective reactors are developed, may be photofermentation or microbial fuel cell technologies. Anaerobic digestion is a currently-available technology and the two-stage process is reported to give greater conversion efficiency than anaerobic digestion alone. (author)

Comparative study on factors affecting anaerobic digestion of agricultural vegetal residues

Directory of Open Access Journals (Sweden)

Cioabla Adrian

2012-06-01

Full Text Available Abstract Background Presently, different studies are conducted related to the topic of biomass potential to generate through anaerobic fermentation process alternative fuels supposed to support the existing fossil fuel resources, which are more and more needed, in quantity, but also in quality of so called green energy. The present study focuses on depicting an optional way of capitalizing agricultural biomass residues using anaerobic fermentation in order to obtain biogas with satisfactory characteristics.. The research is based on wheat bran and a mix of damaged ground grains substrates for biogas production. Results The information and conclusions delivered offer results covering the general characteristics of biomass used , the process parameters with direct impact over the biogas production (temperature regime, pH values and the daily biogas production for each batch relative to the used material. Conclusions All conclusions are based on processing of monitoring process results , with accent on temperature and pH influence on the daily biogas production for the two batches. The main conclusion underlines the fact that the mixture batch produces a larger quantity of biogas, using approximately the same process conditions and input, in comparison to alone analyzed probes, indicating thus a higher potential for the biogas production than the wheat bran substrate. Adrian Eugen Cioabla, Ioana Ionel, Gabriela-Alina Dumitrel and Francisc Popescu contributed equally to this work

Epimerization of D-glucose to L-galactose during the biosynthesis of a sulfated L-galactan in the ascidian tunic

International Nuclear Information System (INIS)

Mourao, P.A.S.

1991-01-01

The sulfated polysaccharides occurring in the tunic of ascidians are unique among known sulfated polysaccharides in that their major constituent sugar is galactose, which occurs exclusively in the L-enantiomeric form. In vitro incorporation experiments using tunic slices incubated with 14 C-labeled sugars revealed that cells from this tissue epimerize D-isomers of hexose into L-galactose during the biosynthesis of their constituent polysaccharides. Compared with other hexoses, the precursor D-[ 14 C]glucose has the highest rate of incorporation and produces the highest proportion of L-galactose units. This metabolic pathway is distinct from the epimerization of D-mannose to L-galactose through its guanosine 5'-diphosphate nucleotide, described previously in an alga and in a snail. Therefore, the epimerization of D-glucose to L-galactose in the ascidian tunic occurs through a novel metabolic route, which involves inversion of the configuration of carbon atoms 2, 3, and 5 of the hexosyl moieties

Impact of Oxidative Stress on Ascorbate Biosynthesis in Chlamydomonas via Regulation of the VTC2 Gene Encoding a GDP-l-galactose Phosphorylase*

Science.gov (United States)

Urzica, Eugen I.; Adler, Lital N.; Page, M. Dudley; Linster, Carole L.; Arbing, Mark A.; Casero, David; Pellegrini, Matteo; Merchant, Sabeeha S.; Clarke, Steven G.

2012-01-01

The l-galactose (Smirnoff-Wheeler) pathway represents the major route to l-ascorbic acid (vitamin C) biosynthesis in higher plants. Arabidopsis thaliana VTC2 and its paralogue VTC5 function as GDP-l-galactose phosphorylases converting GDP-l-galactose to l-galactose-1-P, thus catalyzing the first committed step in the biosynthesis of l-ascorbate. Here we report that the l-galactose pathway of ascorbate biosynthesis described in higher plants is conserved in green algae. The Chlamydomonas reinhardtii genome encodes all the enzymes required for vitamin C biosynthesis via the l-galactose pathway. We have characterized recombinant C. reinhardtii VTC2 as an active GDP-l-galactose phosphorylase. C. reinhardtii cells exposed to oxidative stress show increased VTC2 mRNA and l-ascorbate levels. Genes encoding enzymatic components of the ascorbate-glutathione system (e.g. ascorbate peroxidase, manganese superoxide dismutase, and dehydroascorbate reductase) are also up-regulated in response to increased oxidative stress. These results indicate that C. reinhardtii VTC2, like its plant homologs, is a highly regulated enzyme in ascorbate biosynthesis in green algae and that, together with the ascorbate recycling system, the l-galactose pathway represents the major route for providing protective levels of ascorbate in oxidatively stressed algal cells. PMID:22393048

Development of a simple bio-hydrogen production system through dark fermentation by using unique microflora

Energy Technology Data Exchange (ETDEWEB)

Ohnishi, Akihiro; Bando, Yukiko; Fujimoto, Naoshi; Suzuki, Masaharu [Department of Fermentation Science, Faculty of Applied Bio-Science, Tokyo University of Agriculture, 1-1 Sakuragaoka 1-chome, Setagaya-ku, Tokyo 156-8502 (Japan)

2010-08-15

In order to ensure efficient functioning of hydrogen fermentation systems that use Clostridium as the dominant hydrogen producer, energy-intensive process such as heat pretreatment of inoculum and/or substrate, continuous injection, and control of anaerobic conditions are required. Here, we describe a simple hydrogen fermentation system designed using microflora from leaf-litter cattle-waste compost. Hydrogen and volatile fatty acid production was measured at various hydraulic retention times, and bacterial genera were determined by PCR amplification and sequencing. Although hydrogen fermentation yield was approximately one-third of values reported in previous studies, this system requires no additional treatment and thus may be advantageous in terms of cost and operational control. Interestingly, Clostridium was absent from this system. Instead, Megasphaera elsdenii was the dominant hydrogen-producing bacterium, and lactic acid-producing bacteria (LAB) were prevalent. This study is the first to characterize M. elsdenii as a useful hydrogen producer in hydrogen fermentation systems. These results demonstrate that pretreatment is not necessary for stable hydrogen fermentation using food waste. (author)

An obligately aerobic soil bacterium activates fermentative hydrogen production to survive reductive stress during hypoxia.

Science.gov (United States)

Berney, Michael; Greening, Chris; Conrad, Ralf; Jacobs, William R; Cook, Gregory M

2014-08-05

Oxygen availability is a major factor and evolutionary force determining the metabolic strategy of bacteria colonizing an environmental niche. In the soil, conditions can switch rapidly between oxia and anoxia, forcing soil bacteria to remodel their energy metabolism accordingly. Mycobacterium is a dominant genus in the soil, and all its species are obligate aerobes. Here we show that an obligate aerobe, the soil actinomycete Mycobacterium smegmatis, adopts an anaerobe-type strategy by activating fermentative hydrogen production to adapt to hypoxia. This process is controlled by the two-component system DosR-DosS/DosT, an oxygen and redox sensor that is well conserved in mycobacteria. We show that DosR tightly regulates the two [NiFe]-hydrogenases: Hyd3 (MSMEG_3931-3928) and Hyd2 (MSMEG_2719-2718). Using genetic manipulation and high-sensitivity GC, we demonstrate that Hyd3 facilitates the evolution of H2 when oxygen is depleted. Combined activity of Hyd2 and Hyd3 was necessary to maintain an optimal NAD(+)/NADH ratio and enhanced adaptation to and survival of hypoxia. We demonstrate that fermentatively-produced hydrogen can be recycled when fumarate or oxygen become available, suggesting Mycobacterium smegmatis can switch between fermentation, anaerobic respiration, and aerobic respiration. Hydrogen metabolism enables this obligate aerobe to rapidly meet its energetic needs when switching between microoxic and anoxic conditions and provides a competitive advantage in low oxygen environments.

Separate-stage fermentation of biomass to methane

Energy Technology Data Exchange (ETDEWEB)

Clausen, E C; Gaddy, J L

1978-01-01

The production of CH/sub 4/ from orchard grass by anaerobic fermentation was separated into three stages and the kinetics and economics of the process were evaluated. The first stage was acid hydrolysis of the grass polysaccharides, the second stage was acid and alcohol formation from the sugars with a mixed sewage culture, and the third was CH/sub 4/ formation, also with enriched sewage cultures, from the effluent from the second stage reactor. Separating the steps showed a significant increase in CH/sub 4/ production per g of grass, but was less economical than a single-stage process.

Bioconversion of corncob to hydrogen using anaerobic mixed microflora

Energy Technology Data Exchange (ETDEWEB)

Pan, Chunmei [Department of Chemistry, Zhengzhou University, Daxue Road, Zhengzhou 450052 (China); Biotechnology Department, Zhengzhou College of Animal Husbandry Engineering, Zhengzhou 450011 (China); Zhang, Shufang; Fan, Yaoting; Hou, Hongwei [Department of Chemistry, Zhengzhou University, Daxue Road, Zhengzhou 450052 (China)

2010-04-15

Biohydrogen production from corncob using natural anaerobic microflora was reported for the first time. The optimum pretreatment condition for the corncob was determined to be 100 C, 30 min, and 1% HCl (w/w). The maximum hydrogen yield of 107.9 ml/g-TVS and hydrogen production rate of 4.20 ml/g-TVS h{sup -1} was obtained under the condition of 10 g/l substrate concentration and initial pH 8.0. Butyrate and acetate were the dominant metabolic by-products of hydrogen fermentation. Chemical composition analysis, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to study the mechanism of degrading corncob for hydrogen production. The amorphous domains of cellulose and hemicellulose were hydrolyzed into fermentable saccharides through acid pretreatment and the microorganisms had a devastating effect on the crystallinity of the cellulose. The hydrogen yield from pretreated corncob was much higher than from raw corncob. Therefore, the acid pretreatment played a crucial role on hydrogen production from corncob. (author)

Ethanol Production from Lignocellulose by the Dimorphic Fungus Mucor Indicus

Energy Technology Data Exchange (ETDEWEB)

Lennartsson, P.R.; Taherzadeh, M.J. (School of Engineering, Univ. of Boraas, SE-50190, Boraas (Sweden)). e-mail: Patrik.Lennartsson@hb.se; Karimi, K. (Dept. of Chemical Engineering, Isfahan Univ. of Technology, 84156-83111, Isfahan (IR)); Edebo, L. (Dept. of Clinical Bacteriology, Univ. of Goeteborg, SE-41346, Goeteborg (Sweden))

2008-10-15

Ethanol production from dilute-acid lignocellulosic hydrolyzate by the dimorphic fungus Mucor indicus was investigated. A mixture of different forest wood chips dominated by spruce was hydrolyzed with 0.5 g/L sulfuric acid at 15 bar for 10 min, yielding different sugars including galactose, glucose, mannose, and xylose, but also different fermentation inhibitors such as acetic acid, furfural, hydroxymethyl furfural (HMF), and phenolic compounds. We induced different morphological growth of M. indicus from purely filamentous, mostly filamentous, mostly yeast-like to purely yeast-like. The different forms were then used to ferment the hydrolyzate. They tolerated the presence of the inhibitors under anaerobic batch cultivation well and the ethanol yield was 430-440 g/kg consumed sugars. The ethanol productivity depended on the morphology. Judging from these results, we conclude that M. indicus, is useful for ethanol production from toxic substrates independent of its morphology. Keywords: bio-ethanol, lignocellulosic materials, dilute acid hydrolysis, Mucor indicus, dimorphic fungi

Genome analysis of a Limnobacter sp. identified in an anaerobic methane-consuming cell consortium

Directory of Open Access Journals (Sweden)

Ying Chen

2016-12-01

Full Text Available Species of Limnobacter genus are widespread in a variety of environments, yet knowledges upon their metabolic potentials and mechanisms of environmental adaptation are limited. In this study, a cell aggregate containing Limnobacter and anaerobic methanotrophic archaea (ANME was captured from an enriched anaerobic methane oxidizing (AOM microbial community. A genomic bin of Limnobacter was obtained and analyzed, which provides the first metabolic insights into Limnobacter from an AOM environment. This Limnobacter was found to contain genes involved in the Embden-Meyerhof pathway, the citrate cycle, citronellol degradation, and transporters of various organic substances, indicating a potentially heterotrophic lifestyle. A number of genes involved in sulfur oxidization, oxidative phosphorylation and ethanol fermentation that serve both aerobic and anaerobic purposes have been found in Limnobacter. This work suggests that in the AOM environment, Limnobacter strains may live on the organic substances produced through AOM activity and subsequently may contribute to the AOM community by providing sulfate from sulfur oxidation.

Co-ensiling as a new technique for long-term storage of agro-industrial waste with low sugar content prior to anaerobic digestion.

Science.gov (United States)

Hillion, Marie-Lou; Moscoviz, Roman; Trably, Eric; Leblanc, Yoann; Bernet, Nicolas; Torrijos, Michel; Escudié, Renaud

2018-01-01

Biodegradable wastes produced seasonally need an upstream storage, because of the requirement for a constant feeding of anaerobic digesters. In the present article, the potential of co-ensiling biodegradable agro-industrial waste (sugar beet leaves) and lignocellulosic agricultural residue (wheat straw) to obtain a mixture with low soluble sugar content was evaluated for long-term storage prior to anaerobic digestion. The aim is to store agro-industrial waste while pretreating lignocellulosic biomass. The dynamics of co-ensiling was evaluated in vacuum-packed bags at lab-scale during 180 days. Characterization of the reaction by-products and microbial communities showed a succession of metabolic pathways. Even though the low initial sugars content was not sufficient to lower the pH under 4.5 and avoid undesirable fermentations, the methane potential was not substantially impacted all along the experiment. No lignocellulosic damages were observed during the silage process. Overall, it was shown that co-ensiling was effective to store highly fermentable fresh waste evenly with low sugar content and offers new promising possibilities for constant long-term supply of industrial anaerobic digesters. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of hydro-alcoholic extract of Vitex agnus-castus fruit on kidney of D-galactose-induced aging model in female mice

OpenAIRE

Oroojan, A. A.; Ahangarpour, A.; Khorsandi, L.; Najimi, S. A.

2016-01-01

The aim of the present study was to evaluate the effect of a hydro-alcoholic extract of Vitex agnus-castus (VAC) fruit on blood urea nitrogen (BUN), creatinine (Cr) and, kidney histology of a female mouse model of D-galactose induced aging. In this experimental study, 72 NMRI mice were divided into 6 groups: control, VAC, D-galactose, D-galactose+VAC, aging, and aging+VAC. D-galactose was injected for 45 days and, VAC extract administered in the last 7 days, twice a day. Serum BUN and Cr leve...

Improved inhibitor tolerance in xylose-fermenting yeast Spathaspora passalidarum by mutagenesis and protoplast fusion

DEFF Research Database (Denmark)

Hou, Xiaoru; Yao, Shuo

2012-01-01

The xylose-fermenting yeast Spathaspora passalidarum showed excellent fermentation performance utilizing glucose and xylose under anaerobic conditions. But this yeast is highly sensitive to the inhibitors such as furfural present in the pretreated lignocellulosic biomass. In order to improve...... from fusion of the protoplasts of S. passalidarum M7 and a robust yeast, Saccharomyces cerevisiae ATCC 96581, were able to grow in 75% WSLQ and produce around 0.4 g ethanol/g consumed xylose. Among the selected hybrid strains, the hybrid FS22 showed the best fermentation capacity in 75% WSLQ...... the inhibitor tolerance of this yeast, a combination of UV mutagenesis and protoplast fusion was used to construct strains with improved performance. Firstly, UVinduced mutants were screened and selected for improved tolerance towards furfural. The most promised mutant, S. passalidarum M7, produced 50% more...

Fermentation of household wastes and industrial waste water; Vergaerung von haeuslichen Abfaellen und Industrieabwaessern

Energy Technology Data Exchange (ETDEWEB)

Edelmann, W [Arbeitsgemeinschaft Bioenergie ' arbi' , Maschwanden (Switzerland); Engeli, H [Probag AG, Dietikon (Switzerland); Glauser, M [Biol-Conseils SA, Neuchatel (Switzerland); Hofer, H [HTH-Verfahrenstechnik, Winterthur (Switzerland); Membrez, Y [EREP SA, Aclens (Switzerland); Meylan, J -H [Lausanne (Switzerland); Schwitzguebel, J -P [Swiss Federal Institute of Technology (EPFL), Genie biologique, Lausanne (Switzerland)

1993-07-01

This comprehensive brochure reviews various technologies for the environment-friendly treatment of organic wastes and residues. The principles of anaerobic digestion are discussed. Authorities, planners and engineers concerned with waste treatment are provided with an overview of current technology in the organic wastes area. The brochure emphasises the importance of fermentation processes in waste treatment, discusses the legal pre-requisites for biogas production, lists the biological and process-oriented fundamentals of fermentation and examines the energy potential of biogenic wastes and waste water. Further, details are given on the treatment of both industrial waste water and solid organic wastes and, finally, the economics of fermentation is examined. Useful data is presented in table form and the various processes described are illustrated by schematics and flow diagrams. An appendix lists suggestions for further reading on the subject.

Sustainable fermentative hydrogen production: challenges for process optimisation

Energy Technology Data Exchange (ETDEWEB)

Hawkes, F.R.; Dinsdale, R. [University of Glamorgan, Pontypridd (United Kingdom). School of Applied Sciences; Hawkes, D.L.; Hussy, I. [University of Glamorgan, Pontypridd (United Kingdom). School of Technology

2002-12-01

This paper reviews information from continuous laboratory studies of fermentative hydrogen production useful when considering practical applications of the technology. Data from reactors operating with pure cultures and mixed microflora enriched from natural sources are considered. Inocula have been derived from heat-treated anaerobically digested sludge, activated sludge, aerobic compost and soil, and non-heat-treated aerobically composted activated sludge. Most studies are on soluble defined substrates, and there are few reports of continuous operation on complex substrates with mixed microflora to produce H{sub 2}. Methanogenesis which consumes H{sub 2} may be prevented by operation at short hydraulic retention times (around 8-12 h on simple substrates) and/or pH below 6. Although the reactor technology for anaerobic digestion and biohydrogen production from complex substrates may be similar, there are important microbiological differences, including the need to manage spore germination and oxygen toxicity on start-up and control sporulation in adverse circumstances during reactor operation. (Author)

Biological production of hydrogen by dark fermentation of OFMSW and co-fermentation with slaughterhouse wastes

Energy Technology Data Exchange (ETDEWEB)

Moran, A.; Gomez, X.; Cuestos, M. J.

2005-07-01

Hydrogen is an ideal, clean and sustainable energy source for the future because of its high conversion and nonpolluting nature (Lin and Lay, 2003). There are different methods for the production of hydrogen, the traditional ones, are the production from fossil fuels. Aiming to reach a development based on sustainable principles the production of hydrogen from renewable sources is a desirable goal. Among the environmental friendly alternatives for the production of hydrogen are the biological means. Dark fermentation as it is known the process when light is not used; it is a preferable option thanks to the knowledge already collected from its homologous process, the anaerobic digestion for the production of methane. There are several studies intended to the evaluation of the production of hydrogen, many are dedicated to the use of pure cultures or the utilization of basic substrates as glucose or sucrose (Lin and Lay, 2003; Chang et al., 2002, Kim et al., 2005). This study is performed to evaluate the fermentation of a mixture of wastes for the production of hydrogen. It is used as substrate the organic fraction of municipal solid wastes (OFMSW) and a mixture of this residue with slaughterhouse waste. (Author)

FERMENTABLE SUGARS FROM Lupinus rotundiflorus BIOMASS BY HYDROCHLORIC ACID HYDROLYSIS

Directory of Open Access Journals (Sweden)

Mario A. Ruiz-López

2011-02-01

Full Text Available It is of general interest to produce fermentable carbohydrates from plant biomass. However, obtaining monosaccharides requires some effort, due to the intricate structure of the cell wall lignocellulosic complex. The aim of this study was to apply a simple two-stage hydrolysis process, using only concentrated hydrochloric acid, to generate fermentable carbohydrates from L. rotundiflorus biomass. First and second stage acid concentrations were 32% and 42.6%. Total monosaccharide yields with respect to dry matter after the first stage, second stage, and the overall process, were 27.5%, 21.0% and 48.4%, respectively. Xylose was the main first stage carbohydrate in the hydrolysate, followed by glucose, arabinose, and galactose. After the second stage only glucose and a small amount of xylose were detected. The polysaccharide hydrolysis was eased by overall low lignin content. Some advantages of this method were the use of a single hydrolyzing agent and that most of the polysaccharides were hydrolyzed in reasonably high yields. The acceptable yield, relative simplicity, the use of most of the biomass along with the wide availability, low cost of the chemicals, and the ample supply of lupines, would facilitate the scaling of these laboratory studies to pilot and industrial levels.

[Effects of chrysalis oil on learning, memory and oxidative stress in D-galactose-induced ageing model of mice].

Science.gov (United States)

Chen, Weiping; Yang, Qiongjie; Wei, Xing

2013-11-01

To investigate the effects of chrysalis oil on learning, memory and oxidative stress in D-galactose-induced ageing model of mice. Mice were injected intraperitoneally with D-galactose daily and received chrysalis oil intragastrically simultaneously for 30 d. Then mice underwent space navigation test and spatial probe test, superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) activity and malondialdehyde (MDA) contents in mouse brain were measured. Compared to model group, escape latency in mice treated with 6 ml/kg*d chrysalis oil was significantly shorter (Pchrysalis oil were significantly increased (PChrysalis oil treatment (12ml/kg*d) significantly increased SOD and GSH-PX activity and reduced MDA contents in brain of D-galactose-induced aging mice. Chrysalis oil can improve the ability of learning and memory in D-galactose-induced aging mice, and inhibit peroxidation in brain tissue.

Enhanced hydrogen and 1,3-propanediol production from glycerol by fermentation using mixed cultures

KAUST Repository

Selembo, Priscilla A.

2009-12-15

The conversion of glycerol into high value products, such as hydrogen gas and 1,3-propanediol (PD), was examined using anaerobic fermentation with heat-treated mixed cultures. Glycerol fermentation produced 0.28 mol-H 2/mol-glycerol (72 mL-H2/g-COD) and 0.69 mol-PD/mol-glycerol. Glucose fermentation using the same mixed cultures produced more hydrogen gas (1.06 mol-H2/mol-glucose) but no PD. Changing the source of inoculum affected gas production likely due to prior acclimation of bacteria to this type of substrate. Fermentation of the glycerol produced from biodiesel fuel production (70% glycerol content) produced 0.31 mol-H 2/mol-glycerol (43 mL H2/g-COD) and 0.59 mol-PD/mol-glycerol. These are the highest yields yet reported for both hydrogen and 1,3-propanediol production from pure glycerol and the glycerol byproduct from biodiesel fuel production by fermentation using mixed cultures. These results demonstrate that production of biodiesel can be combined with production of hydrogen and 1,3-propanediol for maximum utilization of resources and minimization of waste. © 2009 Wiley Periodicals, Inc.

Treatment of D-galactose induced mouse aging with Lycium ...

African Journals Online (AJOL)

Kunming mice were randomly divided into the control group, the model group, the high-dose LBP group, and the low-dose LBP group. Except the control group, D-galactose was used for modelling. The drug was administrated when modelling. Mouse behavioural, learning and memory changes were observed, and the ...

Genomic Analysis of Caldithrix abyssi, the Thermophilic Anaerobic Bacterium of the Novel Bacterial Phylum Calditrichaeota

OpenAIRE

Kublanov, Ilya V.; Sigalova, Olga M.; Gavrilov, Sergey N.; Lebedinsky, Alexander V.; Rinke, Christian; Kovaleva, Olga; Chernyh, Nikolai A.; Ivanova, Natalia; Daum, Chris; Reddy, T.B.K.; Klenk, Hans-Peter; Spring, Stefan; G?ker, Markus; Reva, Oleg N.; Miroshnichenko, Margarita L.

2017-01-01

© 2017 Kublanov, Sigalova, Gavrilov, Lebedinsky, Rinke, Kovaleva, Chernyh, Ivanova, Daum, Reddy, Klenk, Spring, Göker, Reva, Miroshnichenko, Kyrpides, Woyke, Gelfand, Bonch-Osmolovskaya. The genome of Caldithrix abyssi, the first cultivated representative of a phylum-level bacterial lineage, was sequenced within the framework of Genomic Encyclopedia of Bacteria and Archaea (GEBA) project. The genomic analysis revealed mechanisms allowing this anaerobic bacterium to ferment peptides or to impl...

Resource and energy recovery options for fermentation industry residuals

Energy Technology Data Exchange (ETDEWEB)

Chiesa, S C [Santa Clara Univ., CA (USA); Manning, Jr, J F [Alabama Univ., Birmingham, AL (USA)

1989-01-01

Over the last 40 years, the fermentation industry has provided facility planners, plant operators and environmental engineers with a wide range of residuals management challenges and resource/energy recovery opportunities. In response, the industry has helped pioneer the use of a number of innovative resource and energy recovery technologies. Production of animal feed supplements, composts, fertilizers, soil amendments, commercial baking additives and microbial protein materials have all been detailed in the literature. In many such cases, recovery of by-products significantly reduces the need for treatment and disposal facilities. Stable, reliable anaerobic biological treatment processes have also been developed to recover significant amounts of energy in the form of methane gas. Alternatively, dewatered or condensed organic fermentation industry residuals have been used as fuels for incineration-based energy recovery systems. The sale or use of recovered by-products and/or energy can be used to offset required processing costs and provide a technically and environmentally viable alternative to traditional treatment and disposal strategies. This review examines resource recovery options currently used or proposed for fermentation industry residuals and the conditions necessary for their successful application. (author).

The effect of heat pretreatment temperature on fermentative hydrogen production using mixed cultures

Energy Technology Data Exchange (ETDEWEB)

Baghchehsaraee, Bita; Nakhla, George; Karamanev, Dimitre; Margaritis, Argyrios [Department of Chemical and Biochemical Engineering, The University of Western Ontario, London, Ontario N6A 5B9 (Canada); Reid, Gregor [Department of Microbiology and Immunology, The University of Western Ontario, London, Ontario (Canada); Canadian Research and Development Center for Probiotics, Lawson Health Research Institute, 268 Grosvenor Street, London, Ontario N6A 4V2 (Canada)

2008-08-15

The effect of heat treatment at different temperatures on two types of inocula, activated sludge and anaerobically digested sludge, was investigated in batch cultures. Heat treatments were conducted at 65, 80 and 95 C for 30 min. The untreated inocula produced less amount of hydrogen than the pretreated inocula, with lactic acid as the main metabolite. The maximum yields of 2.3 and 1.6 mol H{sub 2}/mol glucose were achieved for the 65 C pretreated anaerobically digested and activated sludges, respectively. Approximately a 15% decrease in yield was observed with increasing pretreatment temperature from 65 to 95 C concomitant with an increase in butyrate/acetate ratio from 1.5 to 2.4 for anaerobically digested sludge. The increase of pretreatment temperature of activated sludge to 95 C suppressed the hydrogen production by lactic acid fermentation. DNA analysis of the microbial community showed that the elevated pretreatment temperatures reduced the species diversity. (author)

Genomic Analysis of Caldithrix abyssi, the Thermophilic Anaerobic Bacterium of the Novel Bacterial Phylum Calditrichaeota.

Science.gov (United States)

Kublanov, Ilya V; Sigalova, Olga M; Gavrilov, Sergey N; Lebedinsky, Alexander V; Rinke, Christian; Kovaleva, Olga; Chernyh, Nikolai A; Ivanova, Natalia; Daum, Chris; Reddy, T B K; Klenk, Hans-Peter; Spring, Stefan; Göker, Markus; Reva, Oleg N; Miroshnichenko, Margarita L; Kyrpides, Nikos C; Woyke, Tanja; Gelfand, Mikhail S; Bonch-Osmolovskaya, Elizaveta A

2017-01-01

The genome of Caldithrix abyssi , the first cultivated representative of a phylum-level bacterial lineage, was sequenced within the framework of Genomic Encyclopedia of Bacteria and Archaea (GEBA) project. The genomic analysis revealed mechanisms allowing this anaerobic bacterium to ferment peptides or to implement nitrate reduction with acetate or molecular hydrogen as electron donors. The genome encoded five different [NiFe]- and [FeFe]-hydrogenases, one of which, group 1 [NiFe]-hydrogenase, is presumably involved in lithoheterotrophic growth, three other produce H 2 during fermentation, and one is apparently bidirectional. The ability to reduce nitrate is determined by a nitrate reductase of the Nap family, while nitrite reduction to ammonia is presumably catalyzed by an octaheme cytochrome c nitrite reductase εHao. The genome contained genes of respiratory polysulfide/thiosulfate reductase, however, elemental sulfur and thiosulfate were not used as the electron acceptors for anaerobic respiration with acetate or H 2 , probably due to the lack of the gene of the maturation protein. Nevertheless, elemental sulfur and thiosulfate stimulated growth on fermentable substrates (peptides), being reduced to sulfide, most probably through the action of the cytoplasmic sulfide dehydrogenase and/or NAD(P)-dependent [NiFe]-hydrogenase (sulfhydrogenase) encoded by the genome. Surprisingly, the genome of this anaerobic microorganism encoded all genes for cytochrome c oxidase, however, its maturation machinery seems to be non-operational due to genomic rearrangements of supplementary genes. Despite the fact that sugars were not among the substrates reported when C. abyssi was first described, our genomic analysis revealed multiple genes of glycoside hydrolases, and some of them were predicted to be secreted. This finding aided in bringing out four carbohydrates that supported the growth of C. abyssi : starch, cellobiose, glucomannan and xyloglucan. The genomic analysis

Ethanol from hydrolyzed whey permeate using Saccharomyces cerevisiae in a membrane recycle bioreactor

Energy Technology Data Exchange (ETDEWEB)

Mehaia, M A [King Saud Univ., Buriedah (Saudi Arabia). Dairy Technology Lab.; Cheryan, M [Illinois Univ., Urbana, IL (USA). Agricultural Bioprocess Lab.

1990-02-13

A diauxic fermentation was observed during batch fermentation of enzyme-hydrolyzed whey permeate to ethanol by Saccharomyces cerevisiae. Glucose was consumed before and much faster than galactose. In the continuous membrane recycle bioreactor (MRB), sugar utilization was a function of dilution rate and concentration of sugars. At a cell concentration of 160 kg/m{sup 3}, optimum productivity was 31 kg/(m{sup 3}.h) at ethanol concentration of 65 kg/m{sup 3}. Low levels of acetate (0.05-0.1 M) reduced cell growth during continuous fermentation, but also reduced galactose utilization. (orig.).

Relationship between red meat allergy and sensitization to gelatin and galactose-α-1,3-galactose.

Science.gov (United States)

Mullins, Raymond James; James, Hayley; Platts-Mills, Thomas A E; Commins, Scott

2012-05-01

We have observed patients clinically allergic to red meat and meat-derived gelatin. We describe a prospective evaluation of the clinical significance of gelatin sensitization, the predictive value of a positive test result, and an examination of the relationship between allergic reactions to red meat and sensitization to gelatin and galactose-α-1,3-galactose (α-Gal). Adult patients evaluated in the 1997-2011 period for suspected allergy/anaphylaxis to medication, insect venom, or food were skin tested with gelatin colloid. In vitro (ImmunoCAP) testing was undertaken where possible. Positive gelatin test results were observed in 40 of 1335 subjects: 30 of 40 patients with red meat allergy (12 also clinically allergic to gelatin), 2 of 2 patients with gelatin colloid-induced anaphylaxis, 4 of 172 patients with idiopathic anaphylaxis (all responded to intravenous gelatin challenge of 0.02-0.4 g), and 4 of 368 patients with drug allergy. Test results were negative in all patients with venom allergy (n = 241), nonmeat food allergy (n = 222), and miscellaneous disorders (n = 290). ImmunoCAP results were positive to α-Gal in 20 of 24 patients with meat allergy and in 20 of 22 patients with positive gelatin skin test results. The results of gelatin skin testing and anti-α-Gal IgE measurements were strongly correlated (r = 0.46, P meat were sensitized to gelatin, and a subset was clinically allergic to both. The detection of α-Gal in gelatin and correlation between the results of α-Gal and gelatin testing raise the possibility that α-Gal IgE might be the target of reactivity to gelatin. The pathogenic relationship between tick bites and sensitization to red meat, α-Gal, and gelatin (with or without clinical reactivity) remains uncertain. Copyright © 2012 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

Vitamin and Amino Acid Auxotrophy in Anaerobic Consortia Operating under Methanogenic Conditions.

Science.gov (United States)