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Sample records for continuous alcoholic fermentation

  1. Continuous alcoholic fermentation process: model considering loss of cell viability

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, S.C.; Paiva, T.C.B.; Visconti, A.E.S. [Departamento de Biotecnologia, Faculdade de Engenharia Quimica de Lorena, P.O. BOX 116, 12600-000, Lorena, SP (Brazil); Giudici, R. [Departamento de Engenharia Quimica, Escola Politecnica, Universidade de Sao Paulo, P.O. BOX 61548, 05424-970, Sao Paulo, SP (Brazil)

    1999-02-04

    The concept of loss of cell viability was introduced into a model previously developed for a continuous alcoholic fermentation process in a tower reactor with recycling of flocculating yeasts. The two models take into account substrate limitation and inhibition phenomena linked to ethanol and biomass. The kinetic parameters were estimated from steady-state data of several sugar concentrations in feeding stream and constant dilution rate, recycle ratio and temperature. Some parameters of the modified model (maximum specific rates) were significantly different from those estimated with the original model while others (inhibition parameters) remained practically unchanged. Both models provided similar predictions and were equally suitable for modelling of the process. (orig.) With 1 fig., 2 tabs., 11 refs.

  2. Gravitational sedimentation can solve the problem of cellular recycling of yeast in continuous alcoholic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Maia, A.B.R.A. (Dept. de Engenharia Quimica, Escola de Engenharia da UFMG, Belo Horizonte, MG (Brazil)); Nelson, D.L. (Dept. de Engenharia Quimica, Escola de Engenharia da UFMG, Belo Horizonte, MG (Brazil))

    1993-05-01

    Adjustments in the geometry of the separation zone of an inclined parallel plate sedimenter, previously developed, permitted an extensive increase in the volumetric clarification rate of broth containing yeast (S. cerevisiae). The prototype, having an internal capacity of 1340 ml, was fed with fermentation broth containing 18.8% v/v cells, while 16.4 ml/min of clarified broth containing 0.3% v/v cells was removed in the overflow. The underflow, containing 23.8% v/v cells, was recycled to the fermenter at a rate of 60.6 ml/min. These results demonstrated the viability of using exclusively gravitational sedimentation for cellular recycling in continuous alcoholic fermentation. Without a doubt, this system represents the simplest technological alternative among those thus far proposed for continuous alcoholic fermentation. The low cost of installation, maintenance and operation permitted projection of its application for any scale of production. (orig.)

  3. Application of gravitational sedimentation to efficient cellular recycling in continuous alcoholic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Maia, A.B.R.A.; Nelson, D.L. (Univ. Federal de Minas Gerais, Belo Horizonte, MG (Brazil))

    1993-02-05

    A mathematical model for the sedimentation velocity in an inclined parallel plate sedimenter is proposed. The parameters of the alcoholic fermentation broth (cell density of Saccharomyces cerevisiae, density of the fermentation medium, viscosity of the broth at various alcohol and biomass contents) were determined experimentally. The sedimentation velocities were predicted under various operational conditions and parameters, both of the broth (the alcohol concentration and cell content) and the sedimenter prototype (length, distance between the plates, and slope). The proposed model for the sedimentation velocity presented a good correlation with the experimental results of continuous sedimentation. Three sedimenter prototypes were assembled and tested for efficiency of separation of yeast cells under conditions considered of interest for continuous alcoholic fermentation. A selective filter for the overflow composed of calcium alginate gel improved efficiency (over 98%), and adequate settler residence times (about 20 min) were attained. The operational results permitted the operation of continuous alcoholic fermentation with cellular recycling effected exclusively by gravitational sedimentation, thus characterizing a process of enormous industrial interest because of the operational simplicity and low operational and maintenance costs.

  4. Application of gravitational sedimentation to efficient cellular recycling in continuous alcoholic fermentation.

    Science.gov (United States)

    Maia, A B; Nelson, D L

    1993-02-05

    A mathematical model for the sedimentation velocity in an inclined parallel plate sedimenter is proposed. The parameters of the alcoholic fermentation broth (cell density of Saccharomyces cerevisiae, density of the fermentation medium, viscosity of the broth at various alcohol and biomass contents) were determined experimentally. The sedimentation velocities were predicted under the various operational conditions and parameters, both of the broth (the alcohol concentration and cell content) and the sedimenter prototype (length, distance between the plates, and slope). The proposed model for the sedimentation velocity presented a good correlation with the experimental results of continuous sedimentation. These sedimenter prototypes were assembled and tested for efficiency of separation of yeast cell under conditions considered for interest for continuous alcoholic fermentation. A selective filter for the overflow composed of calcium alginate gel improved operation. A high operational stability, high separation efficiency (over 98%), and adequate settler residence times (about 20 min) were attained. The operational results permitted the operation of continuous alcoholic fermentation with cellular recycling effected exclusively by gravitational sedimentation, this characterizing a process of enormous industrial interest because of the operational simplicity and low operational and maintenance costs.

  5. CONTROL BASED ON NUMERICAL METHODS AND RECURSIVE BAYESIAN ESTIMATION IN A CONTINUOUS ALCOHOLIC FERMENTATION PROCESS

    Directory of Open Access Journals (Sweden)

    Olga L. Quintero

    Full Text Available Biotechnological processes represent a challenge in the control field, due to their high nonlinearity. In particular, continuous alcoholic fermentation from Zymomonas mobilis (Z.m presents a significant challenge. This bioprocess has high ethanol performance, but it exhibits an oscillatory behavior in process variables due to the influence of inhibition dynamics (rate of ethanol concentration over biomass, substrate, and product concentrations. In this work a new solution for control of biotechnological variables in the fermentation process is proposed, based on numerical methods and linear algebra. In addition, an improvement to a previously reported state estimator, based on particle filtering techniques, is used in the control loop. The feasibility estimator and its performance are demonstrated in the proposed control loop. This methodology makes it possible to develop a controller design through the use of dynamic analysis with a tested biomass estimator in Z.m and without the use of complex calculations.

  6. CO₂ from alcoholic fermentation for continuous cultivation of Arthrospira (Spirulina) platensis in tubular photobioreactor using urea as nitrogen source.

    Science.gov (United States)

    Matsudo, Marcelo C; Bezerra, Raquel P; Converti, Attilio; Sato, Sunao; Carvalho, João Carlos M

    2011-01-01

    Carbon dioxide released from alcoholic fermentation accounts for 33% of the whole CO(2) involved in the use of ethanol as fuel derived from glucose. As Arthrospira platensis can uptake this greenhouse gas, this study evaluates the use of the CO(2) released from alcoholic fermentation for the production of Arthrospira platensis. For this purpose, this cyanobacterium was cultivated in continuous process using urea as nitrogen source, either using CO(2) from alcoholic fermentation, without any treatment, or using pure CO(2) from cylinder. The experiments were carried out at 120 μmol photons m(-2) s(-1) in tubular photobioreactor at different dilution rates (0.2 ≤ D ≤ 0.8 d(-1) ). Using CO(2) from alcoholic fermentation, maximum steady-state cell concentration (2661 ± 71 mg L(-1) ) was achieved at D = 0.2 d(-1) , whereas higher dilution rate (0.6 d(-1) ) was needed to maximize cell productivity (839 mg L(-1) d(-1) ). This value was 10% lower than the one obtained with pure CO(2) , and there was no significant difference in the biomass protein content. With D = 0.8 d(-1) , it was possible to obtain 56% ± 1.5% and 50% ± 1.2% of protein in the dry biomass, using pure CO(2) and CO(2) from alcoholic fermentation, respectively. These results demonstrate that the use of such cost free CO(2) from alcoholic fermentation as carbon source, associated with low cost nitrogen source, may be a promising way to reduce costs of continuous cultivation of photosynthetic microorganisms, contributing at the same time to mitigate the greenhouse effect.

  7. Ethanol by continuous fermentation

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    EtOH is produced by continuous fermentation of molasses. Thus, molasses diluted to 20/sup 0/ Brix was inoculated with bakers' yeast and fermented at 32/sup 0/. When the medium reached 4% EtOH, it was circulated through a centrifuge. The concentrated yeast was recycled to the fermentor and the supernatant was sent to a still. After distillation, the still residue was returned to the fermentor. When the initial charge was entirely fermented, 13 kg molasses of 40/sup 0/ Brix was added to the fermentor per hour, and the yield of EtOH was 1.7 kg/100 L-hour.

  8. Neural-networks-based feedback linearization versus model predictive control of continuous alcoholic fermentation process

    Energy Technology Data Exchange (ETDEWEB)

    Mjalli, F.S.; Al-Asheh, S. [Chemical Engineering Department, Qatar University, Doha (Qatar)

    2005-10-01

    In this work advanced nonlinear neural networks based control system design algorithms are adopted to control a mechanistic model for an ethanol fermentation process. The process model equations for such systems are highly nonlinear. A neural network strategy has been implemented in this work for capturing the dynamics of the mechanistic model for the fermentation process. The neural network achieved has been validated against the mechanistic model. Two neural network based nonlinear control strategies have also been adopted using the model identified. The performance of the feedback linearization technique was compared to neural network model predictive control in terms of stability and set point tracking capabilities. Under servo conditions, the feedback linearization algorithm gave comparable tracking and stability. The feedback linearization controller achieved the control target faster than the model predictive one but with vigorous and sudden controller moves. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  9. Mathematical modeling of a continuous alcoholic fermentation process in a two-stage tower reactor cascade with flocculating yeast recycle.

    Science.gov (United States)

    de Oliveira, Samuel Conceição; de Castro, Heizir Ferreira; Visconti, Alexandre Eliseu Stourdze; Giudici, Reinaldo

    2015-03-01

    Experiments of continuous alcoholic fermentation of sugarcane juice with flocculating yeast recycle were conducted in a system of two 0.22-L tower bioreactors in series, operated at a range of dilution rates (D 1 = D 2 = 0.27-0.95 h(-1)), constant recycle ratio (α = F R /F = 4.0) and a sugar concentration in the feed stream (S 0) around 150 g/L. The data obtained in these experimental conditions were used to adjust the parameters of a mathematical model previously developed for the single-stage process. This model considers each of the tower bioreactors as a perfectly mixed continuous reactor and the kinetics of cell growth and product formation takes into account the limitation by substrate and the inhibition by ethanol and biomass, as well as the substrate consumption for cellular maintenance. The model predictions agreed satisfactorily with the measurements taken in both stages of the cascade. The major differences with respect to the kinetic parameters previously estimated for a single-stage system were observed for the maximum specific growth rate, for the inhibition constants of cell growth and for the specific rate of substrate consumption for cell maintenance. Mathematical models were validated and used to simulate alternative operating conditions as well as to analyze the performance of the two-stage process against that of the single-stage process.

  10. Continuous alcoholic fermentation of glucose/xylose mixtures by co-immobilized saccharomyces cerevisiae and candida shehatae

    Energy Technology Data Exchange (ETDEWEB)

    Lebeau, T.; Jouenne, T.; Junter, G.A. [Equipe de Technologie Microbienne, CNRS/Univ. de Rouen, 76 Bois Guillaume (France)

    1998-12-31

    Viable Saccharomyces cerevisiae and Candida shehatae cells were co-immobilized in a composite agar layer/microporous membrane structure. This immobilized-cell structure was placed in a vertical position between the two halves of a double-chambered, stainless-steel bioreactor of original design and applied to the continuous alcoholic fermentation of a mixture of glucose (35 g dm{sup -3}) and xylose (15 g dm{sup -3}). Various dilution rates and initial cell loadings of the gel layer were tested. Simultaneous consumption of the two sugars was always observed. The best fermentation performance was obtained at low dilution rate (0.02 h{sup -1}) with an excess of C. shehatae over S. cerevisiae in the initial cell loading of the gel (5.0 mg dry weight and 0.65 mg dry weight cm{sup -3} gel respectively): 100% of glucose and 73% of xylose were consumed with an ethanol yield coefficient of 0.48 g g total sugars{sup -1}. In these conditions, however, the ethanol production rate per unit volume of gel remained low (0.37 g h{sup -1} dm{sup -3}). Viable cell counts in gel samples after incubation highlighted significant heterogeneities in the spatial distribution of the two yeast species in both the vertical and the transverse directions. In particular, the overall cell number decreased from the bottom to the top of the agar sheet, which may explain the low ethanol productivity relative to the total gel volume. (orig.)

  11. Physiology of yeasts in alcoholic fermentation processes

    OpenAIRE

    Guimarães, Pedro M. R.

    2008-01-01

    Tese de Doutoramento em Engenharia Química e Biológica This thesis is focused on physiological aspects of the yeasts used in two alcoholic fermentation processes: primary brewing fermentation and fermentation of lactose (particularly lactose derived from cheese whey) to ethanol by recombinant Saccharomyces cerevisiae flocculent strains. The brewing fermentation is probably the most extensively studied alcoholic fermentation process. Nevertheless, developments in brewing tech...

  12. Determination of kinetic parameters of fermentation processes by a continuous unsteady-state method: Application to the alcoholic fermentation of D-xylose by Pichia stipitis

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez, H.; Nunez, M.J.; Lema, J.M. (Avda. Ciencias s/n, Santiago (Spain)); Chamy, R. (Univ. Catolica de Valparaiso (Chile))

    1993-05-01

    A quick technique for determination of kinetic parameters of fermentation processes is proposed and applied to the transformation of D-xylose into ethanol by Pichi stipitis. The commonly used method to evaluate these parameters is based on achieving several steady states. In the proposed procedure, [mu][sub m] and K[sub S] can be determined from only one steady state, by provoking a disturbance over it, after allowing the system to return to the original conditions. The main difference between the steady and unsteady state methods is the required fermentation time; while the former method lasted 350 h, the latter required a period 25 times lower. Kinetic and stoichiometric parameters were determined with both methods under anoxic and limited oxygen concentration conditions. Results from the two methods were compared, giving only 2% and 4.5% differences in the values of K[sub S] and [mu][sub m], respectively, under anoxic conditions; 12.5% for K[sub S] and a little over 4% for [mu][sub m] were the deviations under the latter ones.

  13. production of ethyl alcohol from molasses using continuous process

    African Journals Online (AJOL)

    BSN

    stage continuous process using the chemostat system of operation. The highest ethanol ... fermentation process in the production of various products superiority of the process over batch technology .... An integral approach to power alcohol.

  14. Continuous ethanol fermentation by beer yeast

    Energy Technology Data Exchange (ETDEWEB)

    Kida, Kenji; Morimura, Shigeru; Shima, Noriyuki; Asano, Shinichi; Yamadaki, Motozumi; Miyazawa, Toshiki

    1987-01-25

    Cooked and uncooked continuous fermentation tests and a bench-scale continuous fermentation test were carried out using a flocculating yeast, beer yeast IFO-2018, and using molasses of various origin. Heat of fermentation was measured at the same time. High productivity was found in a non-cooking continuous fermentation, but lowering of a flocculating ability was a problem. A theoretical equation for calculating the heat of fermentation was introduced and its adaptability was examined. The continuous fermentation unit was a single tank type using a tower type fermentor. The fermentor had a capacity of 0.7 l actual volume, made of glass, and consisted of the two parts, a flowing part and a precipitation/separation part. The yeast used was Saccharomyces crevisiae IFO-2018 in comparison with such yeast as S. cerevisiae IFO-0224 and S. cervisiae EP-1. (7 figs,3 tabs,21 refs)

  15. Development of fuel alcohol technology. Development of flash fermentation method

    Energy Technology Data Exchange (ETDEWEB)

    1985-08-01

    This is an annual report for 1984 on the development of fuel alcohol fermentation technology. (1) Continuous operation (total 6,000 hours) with a compact fermentation unit (1 l/d alcohol production) increased the productivity up to 1.5 times by a flush fermentation for a high density bacillus. (2) Salt resistance of the bacillus stock for flush fermentation was examined for the selection of the stock to be used in the operation of the test plant. (3) Zaimomonus-mobilis stock was utilized to examine the influence of high-density condition of a light-curing resin on the fermentation characteristics. (4) For a high density bacillus to be loaded in a test plant, a condition for the stable storage for more than 3 months was selected. (5) A test plant with 5 kl/d alcohol production was installed at Izumi Alcohol Plant of NEDO. (6) A unit for preparing high density bacillus granules for loading in the test plant was installed at Kinuura Laboratory of NIKKI K.K..

  16. Carrier-free, continuous primary beer fermentation

    OpenAIRE

    Pires, Eduardo J.; Teixeira, J. A; Brányik, Tomáš; A.A. Vicente

    2014-01-01

    Developing a sustainable continuous fermentation reactor is one of the most ambitious tasks in brewing science, but it could bring great benefits regarding volumetric productivity to modern breweries. Immobilized cell technology is often applied to reach the large densities of yeast needed in a continuous fermentation process. However, the financial cost associated with the use of carriers for yeast immobilization is one of the major drawbacks in the technology. This work suggests that yeast ...

  17. Immobilized yeast bioreactor systems for continuous beer fermentation

    Science.gov (United States)

    Tata; Bower; Bromberg; Duncombe; Fehring; Lau; Ryder; Stassi

    1999-01-01

    Two different types of immobilized yeast bioreactors were examined for continuous fermentation of high-gravity worts. One of these is a fluidized bed reactor (FBR) that employs porous glass beads for yeast immobilization. The second system is a loop reactor containing a porous silicon carbide cartridge (SCCR) for immobilizing the yeast cells. Although there was some residual fermentable sugar in the SCCR system product, nearly complete attenuation of the wort sugars was achieved in either of the systems when operated as a two-stage process. Fermentation could be completed in these systems in only half the time required for a conventional batch process. Both the systems showed similar kinetics of extract consumption, and therefore similar volumetric productivity. As compared to the batch fermentation, total fusel alcohols were lower; total esters, while variable, were generally higher. The yeast biomass production was similar to that in a conventional fermentation process. As would be expected in an accelerated fermentation system, the levels of vicinal diketones (VDKs) were higher. To remove the VDKs, the young beer was heat-treated to convert the VDK precursors and processed through a packed bed immobilized yeast bioreactor for VDK assimilation. The finished product from the FBR system was found to be quite acceptable from a flavor perspective, albeit different from the product from a conventional batch process. Significantly shortened fermentation times demonstrate the feasibility of this technology for beer production.

  18. Production of Star Fruit Alcoholic Fermented Beverage.

    Science.gov (United States)

    Valim, Flávia de Paula; Aguiar-Oliveira, Elizama; Kamimura, Eliana Setsuko; Alves, Vanessa Dias; Maldonado, Rafael Resende

    2016-12-01

    Star fruit (Averrhoa carambola) is a nutritious tropical fruit. The aim of this study was to evaluate the production of a star fruit alcoholic fermented beverage utilizing a lyophilized commercial yeast (Saccharomyces cerevisiae). The study was conducted utilizing a 2(3) central composite design and the best conditions for the production were: initial soluble solids between 23.8 and 25 °Brix (g 100 g(-1)), initial pH between 4.8 and 5.0 and initial concentration of yeast between 1.6 and 2.5 g L(-1). These conditions yielded a fermented drink with an alcohol content of 11.15 °GL (L 100 L(-1)), pH of 4.13-4.22, final yeast concentration of 89 g L(-1) and fermented yield from 82 to 94 %. The fermented drink also presented low levels of total and volatile acidities.

  19. 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.

  20. Software sensor for primary metabolite production case of alcoholic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Roux, G.; Dahhou, B.; Queinnec, I. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France)]|[Institut National des Sciences Appliquees (INSA), 31 - Toulouse (France); Goma, G. [Institut National des Sciences Appliquees (INSA), 31 - Toulouse (France)

    1995-12-31

    This paper investigate the application of an observer for state and parameter estimation to batch, continuous and fed batch fermentations for alcohol production taken as model for a primary metabolite production. This observer is provided to palliate the lack of suitable sensors for on-line biomass and ethanol concentrations measurements and to estimate the time varying specific growth rate. Estimates are obtained from an interlaced structure filter based on a `modified extended Kalman filter` by using on-line measurements of carbon dioxide outflow rate and substrate concentration. The filter algorithm was tested during batch, continuous and fed batch fermentation processes. The filter behaviour observed in the experiments gives good results with an agreement theory/practice. (authors) 18 refs.

  1. Preparation of starchy material for alcoholic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Ustinnikov, B.A.; Yarovenko, V.L.; Maksimova, E.A.

    1968-05-07

    The method involves grinding of the starchy material, heat treatment, exposure of the treated mass to a given temperature, cooling, and saccharification. To reduce losses of fermentable substances, simplify the process, and increase the yield of alcohol., a culture of Bacillus diastaticus is introduced into the ground material prior to heat treatment. The latter is conducted in 2 stages: (1) dissolution and dextrinization of starch at 75 to 95/sup 0/ and (2) sterilization at 125 to 35/sup 0/. Saccharification of the treated material is carried out at 35 to 45/sup 0/.

  2. Preparation of starchy material for alcoholic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Ustinnikov, B.A.; Yarovenko, V.L.; Maksimova, E.A.

    1968-05-07

    The method involves grinding of the starchy material, heat treatment, exposure of the treated mass to a given temperature, cooling, and saccharification. To reduce losses of fermentable substances, simplify the process, and increase the yield of alcohol, a culture of Bacillus diastaticus is introduced into the ground material prior to heat treatment. The latter is conducted in 2 stages: (1) dissolution and dextrinization of starch at 75 to 95 degrees and (2) sterilization at 125 to 35 degrees. Saccharification of the treated material is carried out at 35 to 45 degrees.

  3. New yeast strains for alcoholic fermentation at higher sugar concentration

    Energy Technology Data Exchange (ETDEWEB)

    Bertolini, M.C.; Ernandes, J.R.; Laluce, C. (Universidade Estadual Paulista, Sao Paulo (BR). Inst. de Quimica)

    1991-03-01

    New yeast strains for alcoholic fermentation were isolated from samples collected from Brazilian alcohol factories at the end of the sugar cane crop season. They were selected for their capacity for fermenting sugar cane syrup as well as high sucrose concentrations in synthetic medium with a conversion efficiency of 89.92%. The strains were identified as Saccharomyces cerevisiae. (author).

  4. [Study on immobilized cells for producing alpha-amylase by using polyving alcohol as the carrier(II): The effect of fermentating conditions on the ability producing alpha-amylase of the cells immobilized with polyving alcohol as the corrier and continuous fermentation of the immobilized cells in CSTR].

    Science.gov (United States)

    Liu, Z; Wang, J; Li, Z

    1998-03-01

    The effects of fermentating conditions on the ability of immobilized cells with PVA as carrier for producing alpha-amylase were studied. The continuous fermentation with the immobilized cells were tested in continuous flow stirred tank reactor (CSTR). The results showed that the adaptability of the immobilized Bacillus substilis to pH increased after immobilization. In CSTR, the immobilized cells can be fermentated continuously for 360 hrs and the activity of alpha-amylase can be kept on the level of about 170 u/ml.

  5. 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.

  6. Yeast suspension filtration: Flux enhancement using an upward gas/liquid slug flow -- Application to continuous alcoholic fermentation with cell recycle

    Energy Technology Data Exchange (ETDEWEB)

    Mercier, M.; Maranges, C.; Fonade, C.; Lafforgue-Delorme, C. [Institut National des Sciences Appliquees, Toulouse (France). Centre de Bioingenierie Gilbert Durand

    1998-04-05

    This study deals with the use of an upward gas/liquid slug flow to reduce tubular mineral membrane fouling. The injection of air into the feedstream is designed to create hydrodynamic conditions that destabilize the cake layer over the membrane surface inside the filtration module complex. Experimental study was carried out by filtering a biological suspension (yeast) through different tubular mineral membranes. The effects of operating parameters, including the nature of the membrane, liquid and gas flowrates, and transmembrane pressure, were examined. When external fouling was the main limiting phenomenon, flux enhancements of a factor of three could be achieved was gas sparging compared with single liquid phase crossflow filtration. The economic benefits of this unsteady technique have also been examined. To investigate the possibility of long-term operation of the two-phase flow principle, dense cell perfusion cultures of Saccharomyces cerevisiae were carried out in a fermentor coupled with an ultrafiltration module. The air injection allowed a high and stable flux to be maintained over 100 h of fermentation, with a final cell concentration of 150 g dry weight/L. At equal biomass level, a twofold gain in flux could be attained compared with classical steady crossflow filtration at half the cost.

  7. Asr1, an alcohol-responsive factor of Saccharomyces cerevisiae, is dispensable for alcoholic fermentation.

    Science.gov (United States)

    Izawa, Shingo; Ikeda, Kayo; Kita, Takeomi; Inoue, Yoshiharu

    2006-09-01

    Yeast Asr1 is the first reported protein whose intracellular distribution changes specifically in response to alcohol (Betz et al. (2004) J Biol Chem 279:28174-28181). It was reported that Asr1 is required for tolerance to alcohol and plays an important role in the alcohol stress response. Therefore, Asr1 is of interest to brewers and winegrowers attempting to improve the techniques of alcoholic fermentation. We verified the importance of Asr1 in the alcohol stress response during alcoholic fermentation. Although we reconfirmed the alcohol-responsive changes in the intracellular localization of Asr1, we could not detect the effects of Asr1-deficiency on Japanese sake brewing or winemaking. In addition, we could not reconfirm the hypersensitivity of Asr1-deficient mutants to alcohol and sodium dodecyl sulfate. Instead, we conclude that Asr1 is not required and nor important for tolerance to alcohol stress.

  8. Immobilized yeast cell systems for continuous fermentation applications.

    Science.gov (United States)

    Verbelen, Pieter J; De Schutter, David P; Delvaux, Filip; Verstrepen, Kevin J; Delvaux, Freddy R

    2006-10-01

    In several yeast-related industries, continuous fermentation systems offer important economical advantages in comparison with traditional systems. Fermentation rates are significantly improved, especially when continuous fermentation is combined with cell immobilization techniques to increase the yeast concentration in the fermentor. Hence the technique holds a great promise for the efficient production of fermented beverages, such as beer, wine and cider as well as bio-ethanol. However, there are some important pitfalls, and few industrial-scale continuous systems have been implemented. Here, we first review the various cell immobilization techniques and reactor setups. Then, the impact of immobilization on cell physiology and fermentation performance is discussed. In a last part, we focus on the practical use of continuous fermentation and cell immobilization systems for beer production.

  9. Dominance of Saccharomyces cerevisiae in alcoholic fermentation processes

    DEFF Research Database (Denmark)

    Albergaria, Helena; Arneborg, Nils

    2016-01-01

    Winemaking, brewing and baking are some of the oldest biotechnological processes. In all of them, alcoholic fermentation is the main biotransformation and Saccharomyces cerevisiae the primary microorganism. Although a wide variety of microbial species may participate in alcoholic fermentation...

  10. Chlorine dioxide against bacteria and yeasts from the alcoholic fermentation

    Science.gov (United States)

    Meneghin, Silvana Perissatto; Reis, Fabricia Cristina; de Almeida, Paulo Garcia; Ceccato-Antonini, Sandra Regina

    2008-01-01

    The ethanol production in Brazil is carried out by fed-batch or continuous process with cell recycle, in such way that bacterial contaminants are also recycled and may be troublesome due to the substrate competition. Addition of sulphuric acid when inoculum cells are washed can control the bacterial growth or alternatively biocides are used. This work aimed to verify the effect of chlorine dioxide, a well-known biocide for bacterial decontamination of water and equipments, against contaminant bacteria (Bacillus subtilis, Lactobacillus plantarum, Lactobacillus fermentum and Leuconostoc mesenteroides) from alcoholic fermentation, through the method of minimum inhibitory concentration (MIC), as well as its effect on the industrial yeast inoculum. Lower MIC was found for B. subtilis (10 ppm) and Leuconostoc mesenteroides (50 ppm) than for Lactobacillus fermentum (75 ppm) and Lactobacillus plantarum (125 ppm). Additionally, these concentrations of chlorine dioxide had similar effects on bacteria as 3 ppm of Kamoran® (recommended dosage for fermentation tanks), exception for B. subtilis, which could not be controlled at this Kamoran® dosage. The growth of industrial yeasts was affected when the concentration of chlorine dioxide was higher than 50 ppm, but the effect was slightly dependent on the type of yeast strain. Smooth yeast colonies (dispersed cells) seemed to be more sensitive than wrinkled yeast colonies (clustered cells/pseudohyphal growth), both isolated from an alcohol-producing unit during the 2006/2007 sugar cane harvest. The main advantage in the usage of chlorine dioxide that it can replace antibiotics, avoiding the selection of resistant populations of microorganisms. PMID:24031227

  11. ADAPTIVE CONTROL OF FEED LOAD CHANGES IN ALCOHOL FERMENTATION

    Directory of Open Access Journals (Sweden)

    Folly R.

    1997-01-01

    Full Text Available A fed-batch alcohol fermentation on a pilot plant scale with a digital supervisory control system was evaluated as an experimental application case study of an adaptive controller. The verification of intrinsically dynamic variations in the characteristics of the fermentation, observed in previous work, showed the necessity of an adaptive control strategy for controller parameter tuning in order to adjust the changes in the specific rates of consumption, growth and product formation during the process. Satisfactory experimental results were obtained for set-point variations and sugar feed concentration load changes in the manipulated inlet flow to the fermenter

  12. Simultaneous Saccharification and Fermentation of Overnight Soaked Sweet Potato for Ethyl Alcohol Fermentation

    Directory of Open Access Journals (Sweden)

    B.K. Mishra

    2012-04-01

    Full Text Available The aim of the study is to develop an efficient method of production of ethyl alcohol by fermentation of sweet potato powder. The method emphasized on enhancement of "-amylase accessibility by overnight soaking of sweet potato powder and decreasing unwanted bacterial fermentation by utilizing simultaneous saccharification and fermentation. The crystalline structure of starch limits the accessibility of "-amylase to starch during enzymatic hydrolysis and thus reduces hydrolysis rate. This might be the reason for longer hydrolysis time. Effect of overnight soaking in water on eight variety of sweet potato was investigated followed by Simultaneous Saccharification and Fermentation (SSF. The result reflected the advantage of overnight soaking on "-amylase accessibility to starch, which favor higher hydrolysis rate. Implementing SSF, the fermentation process become efficient due to less free sugar at an instant and maximum efficiency of 96.7% was achieved in a 64.65% starch containing substrate.

  13. Interaction between Hanseniaspora uvarum and Saccharomyces cerevisiae during alcoholic fermentation.

    Science.gov (United States)

    Wang, Chunxiao; Mas, Albert; Esteve-Zarzoso, Braulio

    2015-08-03

    During wine fermentation, Saccharomyces clearly dominate over non-Saccharomyces wine yeasts, and several factors could be related to this dominance. However, the main factor causing the reduction of cultivable non-Saccharomyces populations has not yet been fully established. In the present study, various single and mixed fermentations were performed to evaluate some of the factors likely responsible for the interaction between Saccharomyces cerevisiae and Hanseniaspora uvarum. Alcoholic fermentation was performed in compartmented experimental set ups with ratios of 1:1 and 1:9 and the cultivable population of both species was followed. The cultivable H. uvarum population decreased sharply at late stages when S. cerevisiae was present in the other compartment, similarly to alcoholic fermentations in non-compartmented vessels. Thus, cell-to-cell contact did not seem to be the main cause for the lack of cultivability of H. uvarum. Other compounds related to fermentation performance (such as sugar and ethanol) and/or certain metabolites secreted by S. cerevisiae could be related to the sharp decrease in H. uvarum cultivability. When these factors were analyzed, it was confirmed that metabolites from S. cerevisiae induced lack of cultivability in H. uvarum, however ethanol and other possible compounds did not seem to induce this effect but played some role during the process. This study contributes to a new understanding of the lack of cultivability of H. uvarum populations during the late stages of wine fermentation.

  14. Methods for sequestering carbon dioxide into alcohols via gasification fermentation

    Science.gov (United States)

    Gaddy, James L; Ko, Ching-Whan; Phillips, J. Randy; Slape, M. Sean

    2013-11-26

    The present invention is directed to improvements in gasification for use with synthesis gas fermentation. Further, the present invention is directed to improvements in gasification for the production of alcohols from a gaseous substrate containing at least one reducing gas containing at least one microorganism.

  15. Alcoholic fermentation induces melatonin synthesis in orange juice.

    Science.gov (United States)

    Fernández-Pachón, M S; Medina, S; Herrero-Martín, G; Cerrillo, I; Berná, G; Escudero-López, B; Ferreres, F; Martín, F; García-Parrilla, M C; Gil-Izquierdo, A

    2014-01-01

    Melatonin (N-acetyl-5-methoxytryptamine) is a molecule implicated in multiple biological functions. Its level decreases with age, and the intake of foods rich in melatonin has been considered an exogenous source of this important agent. Orange is a natural source of melatonin. Melatonin synthesis occurs during alcoholic fermentation of grapes, malt and pomegranate. The amino acid tryptophan is the precursor of all 5-methoxytryptamines. Indeed, melatonin appears in a shorter time in wines when tryptophan is added before fermentation. The aim of the study was to measure melatonin content during alcoholic fermentation of orange juice and to evaluate the role of the precursor tryptophan. Identification and quantification of melatonin during the alcoholic fermentation of orange juice was carried out by UHPLC-QqQ-MS/MS. Melatonin significantly increased throughout fermentation from day 0 (3.15 ng/mL) until day 15 (21.80 ng/mL) reaching larger amounts with respect to other foods. Melatonin isomer was also analysed, but its content remained stable ranging from 11.59 to 14.18 ng/mL. The enhancement of melatonin occurred mainly in the soluble fraction. Tryptophan levels significantly dropped from 13.80 mg/L (day 0) up to 3.19 mg/L (day 15) during fermentation. Melatonin was inversely and significantly correlated with tryptophan (r = 0.907). Therefore, the enhancement in melatonin could be due to both the occurrence of tryptophan and the new synthesis by yeast. In summary, the enhancement of melatonin in novel fermented orange beverage would improve the health benefits of orange juice by increasing this bioactive compound.

  16. Monitoring alcoholic fermentation: an untargeted approach.

    Science.gov (United States)

    Ferreira, António César Silva; Monforte, Ana Rita; Teixeira, Carla Silva; Martins, Rosa; Fairbairn, Samantha; Bauer, Florian F

    2014-07-16

    This work describes the utility and efficiency of a metabolic profiling pipeline that relies on an unsupervised and untargeted approach applied to a HS-SPME/GC-MS data. This noninvasive and high throughput methodology enables "real time" monitoring of the metabolic changes inherent to the biochemical dynamics of a perturbed complex biological system and the extraction of molecular candidates that are latter validated on its biochemical context. To evaluate the efficiency of the pipeline five different fermentations, carried on a synthetic media and whose perturbation was the nitrogen source, were performed in 5 and 500 mL. The smaller volume fermentations were monitored online by HS-SPME/GC-MS, allowing to obtain metabolic profiles and molecular candidates time expression. Nontarget analysis was applied using MS data in two ways: (i) one dimension (1D), where the total ion chromatogram per sample was used, (ii) two dimensions (2D), where the integrity time vs m/z per sample was used. Results indicate that the 2D procedure captured the relevant information more efficiently than the 1D. It was also seen that although there were differences in the fermentation performance in different scales, the metabolic pathways responsible for production of metabolites that impact the quality of the volatile fraction was unaffected, so the proposed pipeline is suitable for the study of different fermentation systems that can undergo subsequent sensory validation on a larger scale.

  17. Studies on the kinetics of alcoholic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Godia i Casablancas, F.; Casas Alvero, C.; Sola Ferrando, C.

    1984-01-01

    Yeast isolated from a must was used to ferment a medium containing 50, 98, 150, or 188 g glucose L and the kinetics of cell growth, EtOH formation, and glucose utilization were determined. The results did not agree with the results obtained using 9 different model equations. The models are therefore unsatisfactory.

  18. Fermentation alcohol from grain sorghum starch

    Energy Technology Data Exchange (ETDEWEB)

    Du Preez, J.C.; De Jong, F.; Botes, P.J.; Lategan, P.M.

    1985-01-01

    Grain sorghum is an attractive agricultural feedstock for ethanol production because of its high starch content and the fact that it is more drought-resistant than other cereal crops such as maize. The popular bird-proof grain sorghum variety was investigated. This was subjected to a chemical pretreatment to remove the polyphenolic compounds prior to starch hydrolysis and subsequent fermentation. Starch hydrolysis was accomplished with a commercial alpha-amylase for liquefaction and amyloglucosidase for saccharification. Depending on the saccharification conditions, the hydrolysate contained 65 to 128 g/litre glucose with corresponding maltose concentrations of 50 to 20 g/litre. Several yeast strains were evaluated for their ability to ferment maltose. The total saccharification plus fermentation time could be shortened substantially by inoculating after a brief saccharification period. The addition of ammonium chloride to the hydrolysate improved the fermentation rate. From a 30% grain sorghum slurry an ethanol concentration of over 12% (v/v) was obtained, which was 84% of the theoretical maximum. The data indicated that about 380 litres of ethanol could be produced per ton grain sorghum. 38 references.

  19. Simulation and optimization of continuous extractive fermentation with recycle system

    Science.gov (United States)

    Widjaja, Tri; Altway, Ali; Rofiqah, Umi; Airlangga, Bramantyo

    2017-05-01

    Extractive fermentation is continuous fermentation method which is believed to be able to substitute conventional fermentation method (batch). The recovery system and ethanol refinery will be easier. Continuous process of fermentation will make the productivity increase although the unconverted sugar in continuous fermentation is still in high concentration. In order to make this process more efficient, the recycle process was used. Increasing recycle flow will enhance the probability of sugar to be re-fermented. However, this will make ethanol enter fermentation column. As a result, the accumulated ethanol will inhibit the growth of microorganism. This research aims to find optimum conditions of solvent to broth ratio (S:B) and recycle flow to fresh feed ratio in order to produce the best yield and productivity. This study employed optimization by Hooke Jeeves method using Matlab 7.8 software. The result indicated that optimum condition occured in S: B=2.615 and R: F=1.495 with yield = 50.2439 %.

  20. Modeling as a tool for process control: alcoholic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Tayeb, A.M.; Ashour, I.A.; Mostafa, N.A. (El-Minia Univ. (EG). Faculty of Engineering)

    1991-01-01

    The results of the alcoholic fermentation of beet sugar molasses and wheat milling residues (Akalona) were fed into a computer program. Consequently, the kinetic parameters for these fermentation reactions were determined. These parameters were put into a kinetic model. Next, the model was tested, and the results obtained were compared with the experimental results of both beet molasses and Akalona. The deviation of the experimental results from the results obtained from the model was determined. An acceptable deviation of 1.2% for beet sugar molasses and 3.69% for Akalona was obtained. Thus, the present model could be a tool for chemical engineers working in fermentation processes both with respect to the control of the process and the design of the fermentor. (Author).

  1. Adaptive control of feed load changes in alcohol fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Folly, R.; Berlim, R.; Salgado, A.; Franca, R.; Valdman, B. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica

    1997-12-01

    A fed-batch alcohol fermentation on a pilot plant scale with a digital supervisory control was evaluated as an experimental application case study of an adaptive controller. The verification of intrinsically dynamic variations in the characteristics of the fermentation, observed in previous work, showed the necessity of an adaptive control strategy for controller parameter tuning in order to adjust the changes in the specific rates of consumption, growth and product formation during the process. Satisfactory experimental results were obtained for set-point variations and sugar feed concentration load changes in the manipulated inlet flow to the fermenter. (author) 5 refs., 10 figs., 2 tabs.; e-mail: Valdman at H2O.EQ.UFRJ.BR

  2. Melatonin is synthesised by yeast during alcoholic fermentation in wines.

    Science.gov (United States)

    Rodriguez-Naranjo, M Isabel; Gil-Izquierdo, Angel; Troncoso, Ana M; Cantos-Villar, Emma; Garcia-Parrilla, M Carmen

    2011-06-15

    Melatonin (N-acetyl-5-methoxytryptamine) is a neurohormone produced in the pineal gland. Its biological properties are related to the circadian rhythm. Recently, the European Food Safety Authority (EFSA) accepted the health claim related to melatonin and the alleviation of subjective feelings of jet lag. This molecule has been detected in some foods. In this work, 13 grape varieties were studied; 7 monovarietal wines were produced in an experimental winery under strictly controlled conditions and were sampled in different steps. The grape varieties used to make the wines were: Cabernet Sauvignon, Merlot, Syrah, Tempranillo, Tintilla de Rota, Palomino Fino and Alpha red. Liquid chromatography tandem mass spectrometry (LC-MS/MS) unequivocally confirmed the presence of melatonin in wines. The main contribution of this paper is the results that clearly show that melatonin is synthesised during the winemaking process, specifically after the alcoholic fermentation. Indeed, melatonin is absent in grapes and musts and is formed during alcoholic fermentation.

  3. High cell density cultures produced by internal retention: application in continuous ethanol fermentation

    Directory of Open Access Journals (Sweden)

    Berta Carola Pérez

    2007-04-01

    Full Text Available Ethanol has provoked great interest due to its potential as an alternative fuel. Nevertheless, fermentation processes must be developed by increasing the low volumetric productivity achieved in conventional cultures (batch or continuous to make this product become economically competitive. This can be achieved by using techniques leading to high cell concentration and reducing inhibition by the end-product. One of the frequently employed methods involves cell recycling. This work thus developed a membrane reactor incorporating a filtration module with 5 u,m stainless steel tubular units inside a 3L stirred jar fermenter for investigating its application in continuous ethanol production. The effects of cell concentration and transmembrane pressure difference on permeate flux were evaluated for testing the filtration module's performance. The internal cell retention system was operated in Saccharomyces cerevisiae continuous culture derived from sucrose, once fermentation conditions had been selected (30 °C, 1.25 -1.75 vvm, pH 4.5. Filter unit permeability was maintained by applying pulses of air. More than 97% of the grown cells were retained in the fermenter, reaching 51 g/L cell concentration and 8.51 g/L.h average ethanol productivity in culture with internal cell retention; this was twice that obtained in a conventional continuous culture. Key words: Membrane reactor, Saccharomyces cerevisiae, alcoholic fermentation, cell recycling.

  4. Production of ethyl alcohol with a repetitive batch fermentation method. Kurikaeshi kaibun hakkoho ni yoru alcohol no seizoho

    Energy Technology Data Exchange (ETDEWEB)

    Saiki, T. (Tokyo (Japan)); Takagi, Y. (Chiba (Japan)); Shiba, M. (Kagashima (Japan))

    1994-01-11

    This invention aims to present a production method of ethyl alcohol with a repetitive batch fermentation method in which each batch fermentation is performed rapidly with high concentration of yeast to overcome weak points of conventional procedures and the end point of the fermentation is determined accurately and quickly to switch to the next batch with long-term stability. This invention relates to a production method of ethyl alcohol with repetitive batch fermentation by use of carbohydrate and starchy raw materials, in which a gas flow meter to measure velocity water head is equipped and the end point of the fermentation is judged when the flow rate of fermentation exhaust gas is 0.35-0.1 m[sup 3]/kl[center dot]hr or under. This invention produces ethyl alcohol effectively from raw materials and enables efficient repetitive batch fermentation with less damage of the yeast. 6 figs., 2 tabs.

  5. Alcoholic fermentation of starch by Arxula adeninivorans

    Energy Technology Data Exchange (ETDEWEB)

    Buettner, R.; Bode, R.; Birnbaum, D. (Inst. fuer Biochemie, Greifswald Univ. (Germany))

    1992-04-01

    Yeast strains of Arxula adeninivorans characterized by important industrially properties such as growth at 45deg C and starch utilization were tested for direct conversion of starch to ethanol. All strains produced 9-17 g/l ethanol at 30deg C and for smaller extent (0.2-0.5 g/l) at 45deg C. Ethanol tolerance and some intracellular enzyme activities were determined. Reasons for the relatively small ethanol production in relation to other amylolytic yeasts were the inhibitory effect of ethanol on growth and a low alcohol dehydrogenase level. A higher ethanol production is possible by inducing of ethanol insensitive mutants and cloning of a ADH-gene in A. adeninivorans. (orig.).

  6. Vinegar rice (Oryza sativa L. produced by a submerged fermentation process from alcoholic fermented rice

    Directory of Open Access Journals (Sweden)

    Wilma Aparecida Spinosa

    2015-03-01

    Full Text Available Considering the limited availability of technology for the production of rice vinegar and also due to the potential consumer product market, this study aimed to use alcoholic fermented rice (rice wine (Oryza sativa L. for vinegar production. An alcoholic solution with 6.28% (w/v ethanol was oxidized by a submerged fermentation process to produce vinegar. The process of acetic acid fermentation occurred at 30 ± 0.3°C in a FRINGS® Acetator (Germany for the production of vinegar and was followed through 10 cycles. The vinegar had a total acidity of 6.85% (w/v, 0.17% alcohol (w/v, 1.26% (w/v minerals and 1.78% (w/v dry extract. The composition of organic acids present in rice vinegar was: cis-aconitic acid (6 mg/L, maleic acid (3 mg/L, trans-aconitic acid (3 mg/L, shikimic + succinic acid (4 mg/L, lactic acid (300 mg/L, formic acid (180 mg/L, oxalic acid (3 mg/L, fumaric acid (3 mg/L and itaconic acid (1 mg/L.

  7. Why, when, and how did yeast evolve alcoholic fermentation?

    Science.gov (United States)

    Dashko, Sofia; Zhou, Nerve; Compagno, Concetta; Piškur, Jure

    2014-09-01

    The origin of modern fruits brought to microbial communities an abundant source of rich food based on simple sugars. Yeasts, especially Saccharomyces cerevisiae, usually become the predominant group in these niches. One of the most prominent and unique features and likely a winning trait of these yeasts is their ability to rapidly convert sugars to ethanol at both anaerobic and aerobic conditions. Why, when, and how did yeasts remodel their carbon metabolism to be able to accumulate ethanol under aerobic conditions and at the expense of decreasing biomass production? We hereby review the recent data on the carbon metabolism in Saccharomycetaceae species and attempt to reconstruct the ancient environment, which could promote the evolution of alcoholic fermentation. We speculate that the first step toward the so-called fermentative lifestyle was the exploration of anaerobic niches resulting in an increased metabolic capacity to degrade sugar to ethanol. The strengthened glycolytic flow had in parallel a beneficial effect on the microbial competition outcome and later evolved as a "new" tool promoting the yeast competition ability under aerobic conditions. The basic aerobic alcoholic fermentation ability was subsequently "upgraded" in several lineages by evolving additional regulatory steps, such as glucose repression in the S. cerevisiae clade, to achieve a more precise metabolic control.

  8. Review: Continuous hydrolysis and fermentation for cellulosic ethanol production.

    Science.gov (United States)

    Brethauer, Simone; Wyman, Charles E

    2010-07-01

    Ethanol made biologically from a variety of cellulosic biomass sources such as agricultural and forestry residues, grasses, and fast growing wood is widely recognized as a unique sustainable liquid transportation fuel with powerful economic, environmental, and strategic attributes, but production costs must be competitive for these benefits to be realized. Continuous hydrolysis and fermentation processes offer important potential advantages in reducing costs, but little has been done on continuous processing of cellulosic biomass to ethanol. As shown in this review, some continuous fermentations are now employed for commercial ethanol production from cane sugar and corn to take advantage of higher volumetric productivity, reduced labor costs, and reduced vessel down time for cleaning and filling. On the other hand, these systems are more susceptible to microbial contamination and require more sophisticated operations. Despite the latter challenges, continuous processes could be even more important to reducing the costs of overcoming the recalcitrance of cellulosic biomass, the primary obstacle to low cost fuels, through improving the effectiveness of utilizing expensive enzymes. In addition, continuous processing could be very beneficial in adapting fermentative organisms to the wide range of inhibitors generated during biomass pretreatment or its acid catalyzed hydrolysis. If sugar generation rates can be increased, the high cell densities in a continuous system could enable higher productivities and yields than in batch fermentations. Copyright 2009 Elsevier Ltd. All rights reserved.

  9. On-line ultrasonic velocity monitoring of alcoholic fermentation kinetics.

    Science.gov (United States)

    Resa, Pablo; Elvira, Luis; de Espinosa, Francisco Montero; González, Ramón; Barcenilla, José

    2009-04-01

    In this work, fundamental aspects on the ultrasonic velocity monitoring of alcoholic fermentations in synthetic broths (glucose, fructose and sucrose) and natural media (must and wort) are reported. Results are explained in terms of monosaccharide catabolism, polysaccharide hydrolysis, gas production and microorganism growth. The effect of each one of these subprocesses upon ultrasonic velocity has been independently studied. It is shown that, regarding the sound propagation, the simplest systems behave as ternary dissolutions of sugar and ethanol in water, where, in the course of time, substrates are transformed into metabolites according to the fermentation reaction. A semi-empirical approach, based on the excess volume concept and the density and velocity measurements of binary mixtures, has been used to calculate these magnitudes in the ternary mixtures and to obtain the concentrations of the main solutes throughout the fermentations, reaching a good correlation (especially for the media of simplest composition). In all the processes analyzed, the data obtained from the ultrasonic measurements followed the changes caused by the yeast metabolism, asserting the potential of mechanical waves to monitor fermentations and, in general, biotechnological processes.

  10. Influence of nitrogen sources on growth and fermentation performance of different wine yeast species during alcoholic fermentation

    DEFF Research Database (Denmark)

    Kemsawasd, Varongsiri; Monteiro Lomba Viana, Tiago; Ardö, Ylva

    2015-01-01

    -Saccharomyces yeast species (Lachancea thermotolerans, Metschnikowia pulcherrima, Hanseniaspora uvarum and Torulaspora delbrueckii) was investigated during alcoholic fermentation. Briefly, the N-sources with beneficial effects on all performance parameters (or for the majority of them) for each yeast species were...

  11. Model based Control of a Continuous Yeast Fermentation

    DEFF Research Database (Denmark)

    Andersen, Maria Yolanda; Brabrand, Henrik; Jørgensen, Sten Bay

    1991-01-01

    Control of a continuous fermentation with Saccharomyces cerevisiae is performed by manipulation of the feed flow rate using an ethanol measurement in the exit gas The process is controlled at the critical dilution rate with a low ethanol concentration of 40-50 mg/l. A standard PI controller is able...

  12. Kinetic Study of Acetone-Butanol-Ethanol Fermentation in Continuous Culture

    OpenAIRE

    Buehler, Edward A.; Mesbah, Ali

    2016-01-01

    Acetone-butanol-ethanol (ABE) fermentation by clostridia has shown promise for industrial-scale production of biobutanol. However, the continuous ABE fermentation suffers from low product yield, titer, and productivity. Systems analysis of the continuous ABE fermentation will offer insights into its metabolic pathway as well as into optimal fermentation design and operation. For the ABE fermentation in continuous Clostridium acetobutylicum culture, this paper presents a kinetic model that inc...

  13. Continuous ethanol fermentation of lactose by a recombinant flocculating Saccharomyces cerevisiae strain

    Energy Technology Data Exchange (ETDEWEB)

    Domingues, L.; Dantas, M.M.; Lima, N.; Teixeira, J.A. [Universidade do Minho, Braga (Portugal). Centro do Engeharia Biologica-IBQF

    1999-09-20

    Alcohol fermentation of lactose was investigated using a recombinant flocculating Saccharomyces cetevisiae, expressing the LAC4 (coding the {beta}-galactosidase) and LAC12 (coding for lactose permease) genes of Kluyveromyces marxianus. Data on yeast fermentation and growth on a medium containing lactose as the sole carbon source are presented. In the range of studied lactose concentrations, total lactose consumption was observed with a conversion yield of ethanol close to the expected theoretical value. For the continuously operating bioreactor, an ethanol productivity of 11 g L{sup {minus}1} h{sup {minus}1} (corresponding to a feed lactose concentration of 50 g L{sup {minus}1} and a dilution rate of 0.55 h{sup {minus}1}) was obtained, which is 7 times larger than the continuous conventional systems. The system stability was confirmed by keeping it in operation for 6 months.

  14. Continuous hydrogen production from starch by fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Keigo; Tanisho, Shigeharu [Yokohama National Univ. (Japan)

    2010-07-01

    This study was investigated the effect of hydraulic retention time (HRT) on hydrogen production rate, hydrogen yield and the production rate of volatile fatty acid. The experiment was performed in a continuous stirred tank reactor (CSTR) with a working volume of 1 L by using a Clostridium sp. The temperature of the CSTR was regulated 37 C. The pH was controlled 6.0 by the addition of 3 M of NaOH solution. Starch was used as the carbon source with the concentration of 30 g L{sup -1}. Hydrogen production rate increased from 0.9 L-H{sub 2} L-culture{sup -1} h{sup -1} to 3.2 L-H{sub 2} L-culture{sup -1} h{sup -1} along with the decrease of HRT from 9 h to 1.5 h. Hydrogen yield decreased at low HRT. The major volatile fatty acids are acetic acid, butyric acid and lactic acid. The production rates of acetic acid and butyric acid increased along with the decrease of HRT. On the other hand, the rate of lactic acid was low at high HRT while it increased at HRT 1.5 h. The increase of the production rate of lactic acid suggested one of the reasons that hydrogen yield decreased. (orig.)

  15. Effect of Beverage Containing Fermented Akebia quinata Extracts on Alcoholic Hangover

    OpenAIRE

    2016-01-01

    The present study was conducted to investigate the effects of beverages containing fermented Akebia quinata extracts on alcoholic hangover. For this study, 25 healthy young men were recruited. All participants consumed 100 mL of water (placebo), commercial hangover beverage A or B, fermented A. quinata leaf (AQL) or fruit (AQF) extract before alcohol consumption. After 1 h, all participants consumed a bottle of Soju, Korean distilled liquor (360 mL), containing 20% alcohol. Blood was collecte...

  16. Evidence of metabolic transformations of amino acids into higher alcohols through (13)C NMR studies of wine alcoholic fermentation.

    Science.gov (United States)

    López-Rituerto, Eva; Avenoza, Alberto; Busto, Jesús H; Peregrina, Jesús M

    2010-04-28

    Because the metabolite transformations in wine fermentation processes play a crucial role in the organoleptic and hygienic quality of wines, the nuclear magnetic resonance (NMR) technique is presented as a significant tool to follow metabolic pathways. In this paper, we investigated the transformation of several amino acids into their corresponding higher alcohols during the alcoholic fermentation, showing that the amino acids are totally consumed in the first stages of the process.

  17. Studies of Saccharomyces cerevisiae and Non-Saccharomyces Yeasts during Alcoholic Fermentation

    DEFF Research Database (Denmark)

    Kemsawasd, Varongsiri

    to the early death of L. thermotolerans during mixed-culture alcoholic fermentation with S. cerevisiae. These data may be valuable for development of mixed- and sequential starter cultures for tailoring of wine quality and enhanced flavour profiles. As well, we studied the role of nitrogenous sources...... in completion of anaerobic alcoholic fermentation. For both S. cerevisiae and non-Saccharomyces yeasts, some 22 different nitrogenous sources were evaluated for effects on growth and fermentation ability during anaerobic alcoholic fermentation. The data revealed that nitrogen preference is a trait...... that is species-specific; as well, growth enhancement is also dependent upon the type of nitrogen supplementation for each yeast species. This work provides the first detailed analysis of appropriate nitrogen supplementation to improve yeast growth and alcoholic fermentative activity (i.e., glucose consumption...

  18. Dominance of Saccharomyces cerevisiae in alcoholic fermentation processes: role of physiological fitness and microbial interactions.

    Science.gov (United States)

    Albergaria, Helena; Arneborg, Nils

    2016-03-01

    Winemaking, brewing and baking are some of the oldest biotechnological processes. In all of them, alcoholic fermentation is the main biotransformation and Saccharomyces cerevisiae the primary microorganism. Although a wide variety of microbial species may participate in alcoholic fermentation and contribute to the sensory properties of end-products, the yeast S. cerevisiae invariably dominates the final stages of fermentation. The ability of S. cerevisiae to outcompete other microbial species during alcoholic fermentation processes, such as winemaking, has traditionally been ascribed to its high fermentative power and capacity to withstand the harsh environmental conditions, i.e. high levels of ethanol and organic acids, low pH values, scarce oxygen availability and depletion of certain nutrients. However, in recent years, several studies have raised evidence that S. cerevisiae, beyond its remarkable fitness for alcoholic fermentation, also uses defensive strategies mediated by different mechanisms, such as cell-to-cell contact and secretion of antimicrobial peptides, to combat other microorganisms. In this paper, we review the main physiological features underlying the special aptitude of S. cerevisiae for alcoholic fermentation and discuss the role of microbial interactions in its dominance during alcoholic fermentation, as well as its relevance for winemaking.

  19. Identification of Dekkera bruxellensis as a major contaminant yeast in continuous fuel ethanol fermentation.

    Science.gov (United States)

    de Souza Liberal, A T; Basílio, A C M; do Monte Resende, A; Brasileiro, B T V; da Silva-Filho, E A; de Morais, J O F; Simões, D A; de Morais, M A

    2007-02-01

    To identify and characterize the main contaminant yeast species detected in fuel-ethanol production plants in Northeast region of Brazil by using molecular methods. Total DNA from yeast colonies isolated from the fermentation must of industrial alcohol plants was submitted to PCR fingerprinting, D1/D2 28S rDNA sequencing and species-specific PCR analysis. The most frequent non-Saccharomyces cerevisiae isolates were identified as belonging to the species Dekkera bruxellensis, and several genetic strains could be discriminated among the isolates. The yeast population dynamics was followed on a daily basis during a whole crop harvesting period in a particular industry, showing the potential of D. bruxellensis to grow faster than S. cerevisiae in industrial conditions, causing recurrent and severe contamination episodes. The results showed that D. bruxellensis is one of the most important contaminant yeasts in distilleries producing fuel-ethanol from crude sugar cane juice, specially in continuous fermentation systems. Severe contamination of the industrial fermentation process by Dekkera yeasts has a negative impact on ethanol yield and productivity. Therefore, early detection of D. bruxellensis in industrial musts may avoid operational problems in alcohol-producing plants.

  20. Youths and Alcohol Abuse: A Continuing Phenomenon.

    Science.gov (United States)

    Torres, Donald A.

    1982-01-01

    Defines problem drinking and alcoholism, and differentiates normal drinking escapes from alcohol abuse by teenagers and other youths. Suggests teenagers consume alcohol for a myriad of reasons and this behavior often leads to alcohol dependence which can cause interference in normal relationships with others. (Author)

  1. Probabilistic dietary exposure to ethyl carbamate from fermented foods and alcoholic beverages in the Korean population.

    Science.gov (United States)

    Choi, B; Ryu, D; Kim, C-I; Lee, J-Y; Choi, A; Koh, E

    2017-09-04

    The occurrence of ethyl carbamate was investigated in fermented foods and alcoholic beverages of the Korean total diet study. The concentrations of ethyl carbamate ranged from not detected to 166.5 μg kg(-1). Dietary exposure to ethyl carbamate was estimated by the probabilistic method. Estimated intakes of ethyl carbamate from foods and alcoholic beverages were 4.12 ng kg(-1) body weight (bw) per day for average consumers and 12.37 ng kg(-1) bw/day for 95th percentile high consumers. The major foods contributing to ethyl carbamate exposure were soy sauce (63%), followed by maesilju (plum liqueur, 30%), whisky (5%), and bokbunjaju (black raspberry wine, 2%). On the basis of the benchmark dose lower confidence limit 10% (BMDL10) of 0.3 mg kg(-1) bw/day, margins of exposure were 128,000 for mean exposure and 40,000 for 95th percentile exposure. This indicates that the exposure of the Korean general population for ethyl carbamate is of low concern. However, careful vigilance should be continued for high consumers of fermented foods and alcoholic beverages.

  2. Hyperproduction of Alcohol Using Yeast Fermentation in Highly Concentrated Molasses Medium

    Institute of Scientific and Technical Information of China (English)

    顾燕松; 周政懋; 乔敏; 周全; 陈国强

    2001-01-01

    Cane molasses, a major byproduct in the sugar industry, is generally consumed for alcohol production. However, the alcohol production process needs to overcome three major challenges including increasing the productivity of alcohol fermentation, lowering the energy consumption for alcohol conversion and decreasing the environmental pollution caused by the alcoholic yeast fermentation process. To meet these challenges, a screening process was conducted using 13 high osmotic tolerant yeast strains. Among the strains, a Saccharomyces cerevisiae strain 1912 was found to produce high alcohol concentrations during fermentation with high starting molasses concentrations such as 50% (W/V) molasses. In the test, 13.6% (V/V) alcohol was produced in the molasses fermentation broth after 72 h of incubation with an initial Yunnan molasses concentration of 50% in a 5 L fermentor. 15.0% (V/V) alcohol was obtained after 48 h of fermentation in shaking flasks containing 30% (W/V) initial total sugar concentration in diluted molasses. The performance of this strain in the shaking flasks was successfully scaled up to a 5-L fermentor vessel. Strain 1912 seems to be a better alcohol producer than the currently used alcohol production strain 2. 1190.

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

    Science.gov (United States)

    Schifferdecker, Anna Judith; Siurkus, Juozas; Andersen, Mikael Rørdam; Joerck-Ramberg, Dorte; Ling, Zhihao; Zhou, Nerve; Blevins, James E; Sibirny, Andriy A; Piškur, Jure; Ishchuk, Olena P

    2016-04-01

    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, respectively. The overexpression of ADH3 in D. bruxellensis also reduced the inhibition of fermentation by anaerobiosis, the "Custer effect". Thus, the fermentative capacity of D. bruxellensis could be further improved by metabolic engineering.

  4. Production of solvents (ABE fermentation) from whey permeate by continuous fermentation in a membrane bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Ennis, B.M.; Maddox, I.S.

    1988-12-09

    A continuous bioreactor where cells were recycled using a cross-flow microfiltration (CFM) membrane plant was investigated for the production of solvents (ABE fermentation) from whey permeate using Clostridium acetobutylicum P262. A tubular CFM membrane plant capable of being backflushed was used. The continuous fermentations were characterized by cyclic solventogenic and acidogenic behaviour, and ultimately degenerated to an acidogenic state. Steady-state solvent production was obtained for only short periods. This degeneration is attributed to the complex morphological behaviour of this strain of organism on this substrate. It is postulated that to achieve steady-state solvent production over extended periods of time, it is necessary to maintain a balance among the various morphological cell forms, i.e. acid-producing vegetative cells, solvent-producing clostridial cells, and inert forms, e.g. spores.

  5. 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...

  6. Non-Alcoholic Beverages from Fermented Cereals with Increased Oligosaccharide Content

    National Research Council Canada - National Science Library

    Loreta Basinskiene; Grazina Juodeikiene; Daiva Vidmantiene; Maija Tenkanen; Tomas Makaravicius; Elena Bartkiene

    2016-01-01

      The aim of this study is to develop a new technology for making traditional Lithuanian non-alcoholic beverage kvass from fermented cereals by extending the spectrum of raw materials (extruded rye...

  7. Residual mitochondrial transmembrane potential decreases unsaturated fatty acid level in sake yeast during alcoholic fermentation

    OpenAIRE

    Kazutaka Sawada; Hiroshi Kitagaki

    2016-01-01

    Oxygen, a key nutrient in alcoholic fermentation, is rapidly depleted during this process. Several pathways of oxygen utilization have been reported in the yeast Saccharomyces cerevisiae during alcoholic fermentation, namely synthesis of unsaturated fatty acid, sterols and heme, and the mitochondrial electron transport chain. However, the interaction between these pathways has not been investigated. In this study, we showed that the major proportion of unsaturated fatty acids of ester-linked ...

  8. Study of the alcoholic fermentation of sugars diluted solutions through flow microcalorimetry.

    OpenAIRE

    Volpe, PLO

    1997-01-01

    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 far alcohol fermentation (sucrose, glucose, fructose, manose, maltose, galactose, molasses, honey and sugar cane) and their effects on the heat output recording is discus...

  9. Hybrid Modeling and Optimization of Yogurt Starter Culture Continuous Fermentation

    Directory of Open Access Journals (Sweden)

    Silviya Popova

    2009-10-01

    Full Text Available The present paper presents a hybrid model of yogurt starter mixed culture fermentation. The main nonlinearities within a classical structure of continuous process model are replaced by neural networks. The new hybrid model accounts for the dependence of the two microorganisms' kinetics from the on-line measured characteristics of the culture medium - pH. Then the model was used further for calculation of the optimal time profile of pH. The obtained results are with agreement with the experimental once.

  10. Industrial PE-2 strain of Saccharomyces cerevisiae: from alcoholic fermentation to the production of recombinant proteins.

    Science.gov (United States)

    Soares-Costa, Andrea; Nakayama, Darlan Gonçalves; Andrade, Letícia de Freitas; Catelli, Lucas Ferioli; Bassi, Ana Paula Guarnieri; Ceccato-Antonini, Sandra Regina; Henrique-Silva, Flavio

    2014-01-25

    Saccharomyces cerevisiae is the most important microorganism used in the ethanol fermentation process. The PE-2 strain of this yeast is widely used to produce alcohol in Brazil due to its high fermentation capacity. The aim of the present study was to develop an expression system for recombinant proteins using the industrial PE-2 strain of S. cerevisiae during the alcoholic fermentation process. The protein chosen as a model for this system was CaneCPI-1, a cysteine peptidase inhibitor. A plasmid containing the CaneCPI-1 gene was constructed and yeast cells were transformed with the pYADE4_CaneCPI-1 construct. To evaluate the effect on fermentation ability, the transformed strain was used in the fermentation process with cell recycling. During the nine-hour fermentative cycles the transformed strain did not have its viability and fermentation ability affected. In the last cycle, when the fermentation lasted longer, the protein was expressed probably at the expense of ethanol once the sugars were exhausted. The recombinant protein was expressed in yeast cells, purified and submitted to assays of activity that demonstrated its functionality. Thus, the industrial PE-2 strain of S. cerevisiae can be used as a viable system for protein expression and to produce alcohol simultaneously. The findings of the present study demonstrate the possibility of producing recombinant proteins with biotechnological applications during the ethanol fermentation process.

  11. Metabolic responses of Saccharomyces cerevisiae to valine and ammonium pulses during four-stage continuous wine fermentations.

    Science.gov (United States)

    Clement, T; Perez, M; Mouret, J R; Sanchez, I; Sablayrolles, J M; Camarasa, C

    2013-04-01

    Nitrogen supplementation, which is widely used in winemaking to improve fermentation kinetics, also affects the products of fermentation, including volatile compounds. However, the mechanisms underlying the metabolic response of yeast to nitrogen additions remain unclear. We studied the consequences for Saccharomyces cerevisiae metabolism of valine and ammonium pulses during the stationary phase of four-stage continuous fermentation (FSCF). This culture technique provides cells at steady state similar to that of the stationary phase of batch wine fermentation. Thus, the FSCF device is an appropriate and reliable tool for individual analysis of the metabolic rerouting associated with nutrient additions, in isolation from the continuous evolution of the environment in batch processes. Nitrogen additions, irrespective of the nitrogen-containing compound added, substantially modified the formation of fermentation metabolites, including glycerol, succinate, isoamyl alcohol, propanol, and ethyl esters. This flux redistribution, fulfilling the requirements for precursors of amino acids, was consistent with increased protein synthesis resulting from increased nitrogen availability. Valine pulses, less efficient than ammonium addition in increasing the fermentation rate, were followed by a massive conversion of this amino acid in isobutanol and isobutyl acetate through the Ehrlich pathway. However, additional routes were involved in valine assimilation when added in stationary phase. Overall, we found that particular metabolic changes may be triggered according to the nature of the amino acid supplied, in addition to the common response. Both these shared and specific modifications should be considered when designing strategies to modulate the production of volatile compounds, a current challenge for winemakers.

  12. Biotransformation of chemical constituents of durian wine with simultaneous alcoholic fermentation by Torulaspora delbrueckii and malolactic fermentation by Oenococcus oeni.

    Science.gov (United States)

    Lu, Yuyun; Chua, Jian-Yong; Huang, Dejian; Lee, Pin-Rou; Liu, Shao-Quan

    2016-10-01

    This work represents the first study on the biotransformation of chemical constituents of durian wine via simultaneous alcoholic fermentation (AF) and malolactic fermentation (MLF) with non-Saccharomyces yeast and lactic acid bacteria (LAB), namely, Torulaspora delbrueckii Biodiva and Oenococcus oeni PN4. The presence of PN4 improved the utilization of sugars but did not affect ethanol production. MLF resulted in the significant degradation of malic acid with corresponding increases in pH and lactic acid. The final concentrations of acetic acid (1.29 g/L) and succinic acid (3.70 g/L) in simultaneous AF and MLF were significantly higher than that in AF (1.05 and 1.31 g/L) only. Compared with AF, simultaneous AF and MLF significantly elevated the levels of aroma compounds with higher levels of higher alcohols (isoamyl alcohol, active amyl alcohol, isobutyl alcohol, and 2-phenylethyl alcohol), acetate esters (ethyl acetate, isoamyl acetate), and ethyl esters (ethyl octanoate, ethyl dodecanoate). All the endogenous volatile sulfur compounds decreased to trace or undetectable levels at the end of fermentation. MLF accentuated the reduction of acetaldehyde and sulfides. The initially absent dipropyl disulfide was formed, then catabolized, especially in simultaneous AF and MLF. This study suggested that the simultaneous AF and MLF of non-Saccharomyces and LAB could modify the volatile compositions and potentially modulate the organoleptic properties of durian wine.

  13. Effect of Beverage Containing Fermented Akebia quinata Extracts on Alcoholic Hangover.

    Science.gov (United States)

    Jung, Suhan; Lee, Sang Hoon; Song, Young Sun; Lee, Seo Yeon; Kim, So Young; Ko, Kwang Suk

    2016-03-01

    The present study was conducted to investigate the effects of beverages containing fermented Akebia quinata extracts on alcoholic hangover. For this study, 25 healthy young men were recruited. All participants consumed 100 mL of water (placebo), commercial hangover beverage A or B, fermented A. quinata leaf (AQL) or fruit (AQF) extract before alcohol consumption. After 1 h, all participants consumed a bottle of Soju, Korean distilled liquor (360 mL), containing 20% alcohol. Blood was collected at 0 h, 1 h, 3 h, and 5 h after alcohol consumption. The plasma alanine transaminase (ALT) activity was highest in the placebo group. Compared with the control group, the AQL and AQF groups showed decreased ALT activity at 5 h after alcohol consumption. Plasma ethanol concentration was increased after alcohol intake and peaked at 3 h after alcohol consumption. Compared with the control group, the A group showed a higher plasma ethanol concentration at 1 h (PAQF group showed the lowest mean plasma ethanol concentration compared to the other groups; however, there were no statistical differences. After 5 h of alcohol consumption, the AQL and AQF groups showed lower plasma ethanol concentrations compared with the B group. The sensory evaluation score for the fermented A. quinata fruit extract was lower than for the commercial hangover beverages. In conclusion, the present intervention study results suggest that fermented A. quinata extracts alleviate alcoholic hangover and reduce plasma ethanol concentrations.

  14. Upgrading syngas fermentation effluent using Clostridium kluyveri in a continuous fermentation.

    Science.gov (United States)

    Gildemyn, Sylvia; Molitor, Bastian; Usack, Joseph G; Nguyen, Mytien; Rabaey, Korneel; Angenent, Largus T

    2017-01-01

    The product of current syngas fermentation systems is an ethanol/acetic acid mixture and the goal is to maximize ethanol recovery. However, ethanol currently has a relatively low market value and its separation from the fermentation broth is energy intensive. We can circumvent these disadvantages of ethanol production by converting the dilute ethanol/acetic acid mixture into products with longer carbon backbones, which are of higher value and are more easily extracted than ethanol. Chain elongation, which is the bioprocess in which ethanol is used to elongate short-chain carboxylic acids to medium-chain carboxylic acids (MCCAs), has been studied with pure cultures and open cultures of microbial consortia (microbiomes) with several different substrates. While upgrading syngas fermentation effluent has been studied with open cultures, to our knowledge, no study exists that has performed this with pure cultures. Here, pure cultures of Clostridium kluyveri were used in continuous bioreactors to convert ethanol/acetic acid mixtures into MCCAs. Besides changing the operating conditions in regards to substrate loading rates and composition, the effect of in-line product extraction, pH, and the use of real syngas fermentation effluent on production rates were tested. Increasing the organic loading rates resulted in proportionally higher production rates of n-caproic acid, which were up to 40 mM day(-1) (4.64 g L(-1) day(-1)) at carbon conversion efficiencies of 90% or higher. The production rates were similar for bioreactors with and without in-line product extraction. Furthermore, a lower ethanol/acetic acid ratio (3:1 instead of 10:1) enabled faster and more efficient n-caproic acid production. In addition, n-caprylic acid production was observed for the first time with C. kluyveri (up to 2.19 ± 0.34 mM in batch). Finally, the use of real effluent from syngas fermentation, without added yeast extract, but with added defined growth factors, did maintain similar

  15. Optimization of asparaginase production from Zymomonas mobilis by continuous fermentation

    Directory of Open Access Journals (Sweden)

    Francieli Bortoluzzi Menegat

    2016-10-01

    Full Text Available Asparaginase is an enzyme used in clinical treatments as a chemotherapeutic agent and in food technology to prevent acrylamide formation in fried and baked foods. Asparaginase is industrially produced by microorganisms, mainly gram-negative bacteria. Zymomonas mobilis is a Gram-negative bacterium that utilizes glucose, fructose and sucrose as carbon source and has been known for its efficiency in producing ethanol, sorbitol, levan, gluconic acid and has recently aroused interest for asparaginase production. Current assay optimizes the production of Z. mobilis asparaginase by continuous fermentation using response surface experimental design and methodology. The studied variables comprised sucrose, yeast extract and asparagine. Optimized condition obtained 117.45 IU L-1 with dilution rate 0.20 h-1, yeast extract 0.5 g L-1, sucrose 20 g L-1 and asparagine 1.3 g L-1. Moreover, carbon:nitrogen ratio (1:0.025 strongly affected the response of asparaginase activity. The use of Z. mobilis by continuous fermentation has proved to be a promising alternative for the biotechnological production of asparaginase.

  16. Continuous fermentative hydrogen production in different process conditions

    Energy Technology Data Exchange (ETDEWEB)

    Nasirian, N. [Islamic Azad Univ., Shoushtar (Iran, Islamic Republic of). Dept. of Agricultural Mechanization; Almassi, M.; Minaee, S. [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Dept. of Agricultural Mechanization; Widmann, R. [Duisburg-Essen Univ., Essen (Germany). Dept. of Environmental Engineering, Waste and Water

    2010-07-01

    This paper reported on a study in which hydrogen was produced by fermentation of biomass. A continuous process using a non-sterile substrate with a readily available mixed microflora was used on heat treated digested sewage sludge from a wastewater treatment plant. Hydrogen was produced from waste sugar at a pH of 5.2 and a temperature of 37 degrees C. An experimental setup of three 5.5 L working volume continuously stirred tank reactors (CSTR) in different stirring speeds were constructed and operated at 7 different hydraulic retention times (HRTs) and different organic loading rates (OLR). Dissolved organic carbon was examined. The results showed that the stirring speed of 135 rpm had a beneficial effect on hydrogen fermentation. The best performance was obtained in 135 rpm and 8 h of HRT. The amount of gas varied with different OLRs, but could be stabilized on a high level. Methane was not detected when the HRT was less than 16 h. The study identified the reactor in which the highest specific rate of hydrogen production occurred.

  17. Production of ethyl alcohol by a repeated batch fermentation method. Kurikaeshi kaibun hakkoho ni yoru arukoru no seizoho

    Energy Technology Data Exchange (ETDEWEB)

    Saiki, T. (Tokyo (Japan)); Takagi, Y. (Chiba (Japan)); Shiba, M. (Kagoshima (Japan))

    1994-01-11

    This invention relates to a production method of ethyl alcohol from sugar and starch raw materials by a repeated batch fermentation method and aims to provide a method to produce ethyl alcohol efficiently by accurate repetition. Conventional batch fermentation methods require the experiences and skill to confirm an end point of the fermentation and have a problem in a control of repeated batch fermentation. This invention uses a gas flow meter of a velocity head measurement type and judges an end point of fermentation at a time when the amount of the exhaust gas flow from the fermentation is 0.35 to 0.1 m[sup 3] per hour and per 1 kl fermentation liquid or below and the next batch fermentation is started. By this invention, ethyl alcohol is produced efficiently from the raw materials with less damage of the yeast and efficient repeated batch fermentation is realized. 6 figs., 1 tab.

  18. Bioreactor design for continuous dark fermentative hydrogen production.

    Science.gov (United States)

    Jung, Kyung-Won; Kim, Dong-Hoon; Kim, Sang-Hyoun; Shin, Hang-Sik

    2011-09-01

    Dark fermentative H2 production (DFHP) has received increasing attention in recent years due to its high H2 production rate (HPR) as well as the versatility of the substrates used in the process. For most studies in this field, batch reactors have been applied due to their simple operation and efficient control; however, continuous DFHP operation is necessary from economical and practical points of view. Continuous systems can be classified into two categories, suspended and immobilized bioreactors, according to the life forms of H2 producing bacteria (HPB) used in the reactor. This paper reviews operational parameters for bioreactor design including pH, temperature, hydraulic retention time (HRT), and H2 partial pressure. Also, in this review, various bioreactor configurations and performance parameters including H2 yield (HY), HPR, and specific H2 production rate (SHPR) are evaluated and presented.

  19. Optimization of batch alcoholic fermentation of Cyperus esculentus

    Energy Technology Data Exchange (ETDEWEB)

    Esuoso, K.O. (Dept. of Chemistry, Federal Univ. of Technology, Akure (Nigeria)); Oderinde, R.A. (Dept. of Chemistry, Ibadan Univ. (Nigeria)); Vega-Catalan, F.J. (Dept. of Computer Science, Ibadan Univ. (Nigeria)); Bamiro, F.O. (Dept. of Chemical Sciences, Univ. of Agriculture, Abeokuta (Nigeria))

    1993-01-01

    In our earlier work carried out on alcoholic fermentation of molasses the optimum sugar concentration was between 14.0 and 17.0% w/v sugars, beyond which ethanol content decreased drastically. However in the present work, ethanol concentration was still high at 20% w/v sugars. This suggested that the strain had enhanced tolerance to the adverse effects of C. esculentus medium than molasses. Substituting the calculated parameter values (a[sub 1]-a[sub 10]) and optimal conditions of pH, S and T into equation, the calculated yield equals 92.7%. We again tried to verify experimentally the reliability of the theoretical optimal values obtained. The concentration of ethanol obtained was 9.2 [+-] 0.2% v/v. This was higher than the maximum concentration recorded before simulation (8.9% v/v). The experimental yield obtained was 90.3 [+-] 1.6% which is in close agreement with the simulated value of 92.7%. (orig.)

  20. Kinetic Study of Acetone-Butanol-Ethanol Fermentation in Continuous Culture.

    Science.gov (United States)

    Buehler, Edward A; Mesbah, Ali

    2016-01-01

    Acetone-butanol-ethanol (ABE) fermentation by clostridia has shown promise for industrial-scale production of biobutanol. However, the continuous ABE fermentation suffers from low product yield, titer, and productivity. Systems analysis of the continuous ABE fermentation will offer insights into its metabolic pathway as well as into optimal fermentation design and operation. For the ABE fermentation in continuous Clostridium acetobutylicum culture, this paper presents a kinetic model that includes the effects of key metabolic intermediates and enzymes as well as culture pH, product inhibition, and glucose inhibition. The kinetic model is used for elucidating the behavior of the ABE fermentation under the conditions that are most relevant to continuous cultures. To this end, dynamic sensitivity analysis is performed to systematically investigate the effects of culture conditions, reaction kinetics, and enzymes on the dynamics of the ABE production pathway. The analysis provides guidance for future metabolic engineering and fermentation optimization studies.

  1. Kinetic Study of Acetone-Butanol-Ethanol Fermentation in Continuous Culture

    Science.gov (United States)

    Buehler, Edward A.; Mesbah, Ali

    2016-01-01

    Acetone-butanol-ethanol (ABE) fermentation by clostridia has shown promise for industrial-scale production of biobutanol. However, the continuous ABE fermentation suffers from low product yield, titer, and productivity. Systems analysis of the continuous ABE fermentation will offer insights into its metabolic pathway as well as into optimal fermentation design and operation. For the ABE fermentation in continuous Clostridium acetobutylicum culture, this paper presents a kinetic model that includes the effects of key metabolic intermediates and enzymes as well as culture pH, product inhibition, and glucose inhibition. The kinetic model is used for elucidating the behavior of the ABE fermentation under the conditions that are most relevant to continuous cultures. To this end, dynamic sensitivity analysis is performed to systematically investigate the effects of culture conditions, reaction kinetics, and enzymes on the dynamics of the ABE production pathway. The analysis provides guidance for future metabolic engineering and fermentation optimization studies. PMID:27486663

  2. Comparative studies on the alcohol types presence in Gracilaria sp. and rice fermentation using Sasad

    Science.gov (United States)

    Mansa, R.; Mansuit, H.; Sipaut, C. S.; Yee, C. F.; Yasir, S. M.

    2016-06-01

    Alternative fuel sources such as biofuels are needed in order to overcome environmental problem caused by fossil fuel consumption. Currently, most biofuel are produced from land based crops and there is a possibility that marine biomass such as macroalgae can be an alternative source for biofuel production. The carbohydrate in macroalgae can be broken down into simple sugar through thermo-chemical hydrolysis and enzymatic hydrolysis. Dilute-acid hydrolysis was believed to be the most available and affordable method. However, the process may release inhibitors which would affect alcohol yield from fermentation. Thus, this work was aimed at investigating if it is possible to avoid this critical pre-treatment step in macroalgae fermentation process by using Sasad, a local Sabahan fermentation agent and to compare the yield with rice wine fermentation. This work hoped to determine and compare the alcohol content from Gracilaria sp. and rice fermentation with Sasad. Rice fermentation was found containing ethanol and 2 - methyl - 1 - propanol. Fermentation of Gracilaria sp. had shown the positive presence of 3 - methyl - 1 - butanol. It was found that Sasad can be used as a fermentation agent for bioalcohol production from Gracilaria sp. without the need for a pretreatment step. However further investigations are needed to determine if pre-treatment would increase the yield of alcohol.

  3. Use of Saccharomyces cerevisiae cells immobilized on orange peel as biocatalyst for alcoholic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Plessas, S.; Bekatorou, A; Koutinas, A.A.; Soupioni, M. [University of Patras (Greece). Department of Chemistry, Food Biotechnology Group; Banat, I.M.; Marchant, R. [University of Ulster, Coleraine, N. Ireland (United Kingdom). School of Biomedical Sciences

    2007-03-15

    A biocatalyst was prepared by immobilizing a commercial Saccharomyces cerevisiae strain (baker's yeast) on orange peel pieces for use in alcoholic fermentation and for fermented food applications. Cell immobilization was shown by electron microscopy and by the efficiency of the immobilized biocatalyst for alcoholic fermentation of various carbohydrate substrates (glucose, molasses, raisin extracts) and at various temperatures (30-15 {sup o}C). Fermentation times in all cases were low (5-15 h) and ethanol productivities were high (av. 150.6 g/ld) showing good operational stability of the biocatalyst and suitability for commercial applications. Reasonable amounts of volatile by-products were produced at all temperatures studied, revealing potential application of the proposed biocatalyst in fermented food applications, to improve productivities and quality. (author)

  4. Special Beer obtained by Synchronous Alcoholic Fermentation of Two Different Origin Substrates

    Directory of Open Access Journals (Sweden)

    Elena MUDURA

    2016-11-01

    Full Text Available Beer is the most consumed alcoholic beverage worldwide. Both beer and wine are  recognized since ancient times for their health benefits. Nowadays, these beverages are consumed for its sensory, social interaction, and recently even in culinary dishes. In addition, studies showed the benefits of beer moderate consumption on health. Beer is a low-alcohol beverage and also presents many nutritional properties outlined by its nutritional content rich in vitamins, minerals and antioxidants that come from the raw material (malt and hop. Wishing to attract as many niches of consumers, brewers tend to produce every year new and innovative beers. The purpose of this study was to develop the technology for an innovative special beer. The synchronous alcoholic fermentation of two different origin substrates – wort and grape must - was monitored and their composition was assessed in order to obtain special beer with superior sensory properties. Technological process was developed in the Winery Pilot Station of the UASVM Cluj-Napoca. Special beer was obtained by alcoholic fermentation of hopped dark wort with grape must from the autochthonous Feteasca neagra grapes variety. Second fermentation process was followed by the maturation (3 weeks at 5oC in order to harmonize sensory qualities. The entire process was monitored considering fermentation and final products physicochemical parameters. The optimized ratio of the two fermentation substrates was of 2.5:3 on primary raw materials – beer wort and grapes must. The process was monitored on optimizing the fermentation process. The best fermentation yield was obtained when lower fermentation extracts were used. This study demonstrated that the simultaneous fermentation of the two substrates with different glucidic origin may proceed under controlled conditions and may be carried out so as to obtain the desired fermentation products with improved sensorial properties and increased health benefits.

  5. Continuous dry fermentation of swine manure for biogas production

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chuang; Zheng, Dan [Biogas Institute of Ministry of Agriculture, Chengdu 610041 (China); Liu, Gang–Jin [Biogas Institute of Ministry of Agriculture, Chengdu 610041 (China); Bioprocess Control AB, Scheelevägen 22, 223 63 Lund (Sweden); Deng, Liang–Wei, E-mail: dengliangwei@caas.cn [Biogas Institute of Ministry of Agriculture, Chengdu 610041 (China); Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture, Chengdu 610041 (China); Southwest Collaborative Innovation Center of Swine for Quality & Safety, Chengdu 611130 (China); Long, Yan; Fan, Zhan–Hui [Biogas Institute of Ministry of Agriculture, Chengdu 610041 (China)

    2015-04-15

    Highlights: • Continuous dry fermentation of swine manure for biogas production is feasible. • The feedstock TS concentration exerted a significant impact on biogas production. • Influences of ammonia and digestate liquidity were investigated in this study. • The results showed that the feedstock TS of swine manure should not exceed 30%. - Abstract: A down plug-flow anaerobic reactor (DPAR) was designed for the feasibility study on continuous dry fermentation of swine manure without any additional stirring. Using fresh swine manure as the feedstock with TS concentration (w/w) of 20%, 25%, 30%, and 35%, stable volumetric biogas production rates of 2.40, 1.92, 0.911, and 0.644 L·(L d){sup −1} and biogas yields of 0.665, 0.532, 0.252, and 0.178 L g{sup −1}VS were obtained respectively, and the TS degradation rates were 46.5%, 45.4%, 53.2%, and 55.6%, respectively. With the increase of feedstock TS concentration, the concentration of ammonia nitrogen grew up to the maximum value of 3500 mg L{sup −1}. Biogas production was obviously inhibited when the concentration of ammonia nitrogen was above 3000 mg L{sup −1}. The maximal volumetric biogas production rate of 2.34 L·(L d){sup −1} and biogas yield of 0.649 L g{sup −1}VS were obtained with TS concentration of 25% at 25 °C without inhibition. Liquidity experiments showed that TS concentration of digestate could be less than 15.8%, and the flow rate of digestate more than 0.98 m s{sup −1} when the feedstock TS concentration was less than 35%, which indicated the digestate could be easily discharged from a DPAR. Therefore, it is feasible to conduct a continuous dry fermentation in a DPAR using fresh swine manure as the feedstock with TS concentration less than 35%, whereas the feedstock TS concentration should not exceed 30% to achieve the maximal biogas production rate and biogas yield.

  6. Enhanced phenylpyruvic acid production with Proteus vulgaris in fed-batch and continuous fermentation.

    Science.gov (United States)

    Coban, Hasan B; Demirci, Ali; Patterson, Paul H; Elias, Ryan J

    2016-01-01

    Phenylpyruvic acid is a deaminated form of phenylalanine and is used in various areas such as development of cheese and wine flavors, diagnosis of phenylketonuria, and to decrease excessive nitrogen accumulation in the manure of farm animals. However, reported phenylpyruvic acid fermentation studies in the literature have been usually performed at shake-flask scale with low production. In this study, phenylpyruvic acid production was evaluated in bench-top bioreactors by conducting fed-batch and continuous fermentation for the first time. As a result, maximum phenylpyruvic acid concentrations increased from 1350 mg/L (batch fermentation) to 2958 mg/L utilizing fed-batch fermentation. Furthermore, phenylpyruvic acid productivity was increased from 48 mg/L/hr (batch fermentation) to 104 and 259 mg/L/hr by conducting fed-batch and continuous fermentation, respectively. Overall, this study demonstrated that fed-batch and continuous fermentation significantly improved phenylpyruvic acid production in bench-scale bioreactor production.

  7. Hydrogen production by Clostridium thermolacticum during continuous fermentation of lactose

    Energy Technology Data Exchange (ETDEWEB)

    Collet, C.; Adler, N.; Schwitzguebel, J.P.; Peringer, P. [Swiss Federal Inst. of Technology Lausanne (EPFL) (Switzerland). Lab. for Environmental Biotechnology

    2004-11-01

    In the production of acetate by Clostridium thermolacticum growing on lactose, considerable amounts of hydrogen were generated. Lactose available in large amounts from milk permeate, a waste stream of the dairy industry, appears to be a valuable substrate for cheap production of biohydrogen. In this study, continuous cultivation of C. thermolacticum was carried out in a bioreactor, under anaerobic thermophilic conditions, on minimal medium containing 10 g l{sup -1} lactose. Different dilution rates and pH were tested. C. thermolacticum growing on lactose produced acetate, ethanol and lactate in the liquid phase. For all conditions tested, hydrogen was the main product in the gas phase. Hydrogen specific production higher than 5 mmol H{sub 2} (g cell){sup -1} h{sup -1} was obtained. By operating this fermentation at high-dilution rate and alkaline pH, the hydrogen content in the gas phase was maximized. (author)

  8. Study on methane fermentation and production of vitamin B12 from alcohol waste slurry.

    Science.gov (United States)

    Zhang, Zhenya; Quan, Taisheng; Li, Pomin; Zhang, Yansheng; Sugiura, Norio; Maekawa, Takaaki

    2004-01-01

    We studied biogas fermentation from alcohol waste fluid to evaluate the anaerobic digestion process and the production of vitamin B12 as a byproduct. Anaerobic digestion using acclimated methanogens was performed using the continuously stirred tank reactor (CSTR) and fixed-bed reactor packed with rock wool as carrier material at 55 degrees C. We also studied the effects of metal ions added to the culture broth on methane and vitamin B12 formation. Vitamin B12 production was 2.92 mg/L in the broth of the fixed-bed reactor, twice that of the CSTR. The optimum concentrations of trace metal ions added to the culture liquid for methane and vitamin B12 production were 1.0 and 8 mL/L for the CSTR and fixed-bed reactor, respectively. Furthermore, an effective method for extracting and purifying vitamin B12 from digested fluid was developed.

  9. Continuous dry fermentation of swine manure for biogas production.

    Science.gov (United States)

    Chen, Chuang; Zheng, Dan; Liu, Gang-Jin; Deng, Liang-Wei; Long, Yan; Fan, Zhan-Hui

    2015-04-01

    A down plug-flow anaerobic reactor (DPAR) was designed for the feasibility study on continuous dry fermentation of swine manure without any additional stirring. Using fresh swine manure as the feedstock with TS concentration (w/w) of 20%, 25%, 30%, and 35%, stable volumetric biogas production rates of 2.40, 1.92, 0.911, and 0.644L · (Ld)(-1) and biogas yields of 0.665, 0.532, 0.252, and 0.178 L g(-)(1)VS were obtained respectively, and the TS degradation rates were 46.5%, 45.4%, 53.2%, and 55.6%, respectively. With the increase of feedstock TS concentration, the concentration of ammonia nitrogen grew up to the maximum value of 3500 mg L(-1). Biogas production was obviously inhibited when the concentration of ammonia nitrogen was above 3000 mg L(-1). The maximal volumetric biogas production rate of 2.34 L ·(Ld)(-1) and biogas yield of 0.649 L g(-1)VS were obtained with TS concentration of 25% at 25°C without inhibition. Liquidity experiments showed that TS concentration of digestate could be less than 15.8%, and the flow rate of digestate more than 0.98 m s(-1) when the feedstock TS concentration was less than 35%, which indicated the digestate could be easily discharged from a DPAR. Therefore, it is feasible to conduct a continuous dry fermentation in a DPAR using fresh swine manure as the feedstock with TS concentration less than 35%, whereas the feedstock TS concentration should not exceed 30% to achieve the maximal biogas production rate and biogas yield.

  10. Residual mitochondrial transmembrane potential decreases unsaturated fatty acid level in sake yeast during alcoholic fermentation.

    Science.gov (United States)

    Sawada, Kazutaka; Kitagaki, Hiroshi

    2016-01-01

    Oxygen, a key nutrient in alcoholic fermentation, is rapidly depleted during this process. Several pathways of oxygen utilization have been reported in the yeast Saccharomyces cerevisiae during alcoholic fermentation, namely synthesis of unsaturated fatty acid, sterols and heme, and the mitochondrial electron transport chain. However, the interaction between these pathways has not been investigated. In this study, we showed that the major proportion of unsaturated fatty acids of ester-linked lipids in sake fermentation mash is derived from the sake yeast rather than from rice or koji (rice fermented with Aspergillus). Additionally, during alcoholic fermentation, inhibition of the residual mitochondrial activity of sake yeast increases the levels of unsaturated fatty acids of ester-linked lipids. These findings indicate that the residual activity of the mitochondrial electron transport chain reduces molecular oxygen levels and decreases the synthesis of unsaturated fatty acids, thereby increasing the synthesis of estery flavors by sake yeast. This is the first report of a novel link between residual mitochondrial transmembrane potential and the synthesis of unsaturated fatty acids by the brewery yeast during alcoholic fermentation.

  11. Residual mitochondrial transmembrane potential decreases unsaturated fatty acid level in sake yeast during alcoholic fermentation

    Directory of Open Access Journals (Sweden)

    Kazutaka Sawada

    2016-01-01

    Full Text Available Oxygen, a key nutrient in alcoholic fermentation, is rapidly depleted during this process. Several pathways of oxygen utilization have been reported in the yeast Saccharomyces cerevisiae during alcoholic fermentation, namely synthesis of unsaturated fatty acid, sterols and heme, and the mitochondrial electron transport chain. However, the interaction between these pathways has not been investigated. In this study, we showed that the major proportion of unsaturated fatty acids of ester-linked lipids in sake fermentation mash is derived from the sake yeast rather than from rice or koji (rice fermented with Aspergillus. Additionally, during alcoholic fermentation, inhibition of the residual mitochondrial activity of sake yeast increases the levels of unsaturated fatty acids of ester-linked lipids. These findings indicate that the residual activity of the mitochondrial electron transport chain reduces molecular oxygen levels and decreases the synthesis of unsaturated fatty acids, thereby increasing the synthesis of estery flavors by sake yeast. This is the first report of a novel link between residual mitochondrial transmembrane potential and the synthesis of unsaturated fatty acids by the brewery yeast during alcoholic fermentation.

  12. Bacillus vini sp. nov. isolated from alcohol fermentation pit mud.

    Science.gov (United States)

    Ma, Kedong; Chen, Xiaorong; Guo, Xiang; Wang, Yanwei; Wang, Huimin; Zhou, Shan; Song, Jinlong; Kong, Delong; Zhu, Jie; Dong, Weiwei; He, Mingxiong; Hu, Guoquan; Zhao, Bingqiang; Ruan, Zhiyong

    2016-08-01

    A novel aerobic, Gram-stain-positive, sporogenous, rod-shaped bacterium, designated LAM0415(T), was isolated from an alcohol fermentation pit mud sample collected from Sichuan Luzhou-flavour liquor enterprise in China. The isolate was found to be able to grow at NaCl concentrations of 0-10 % (w/v) (optimum: 1.0 %), 10-50 °C (optimum: 30-35 °C) and pH 3.0-10.0 (optimum: 7.0-8.0). Phylogenetic analysis of 16S rRNA gene sequences indicated that the new isolate belonged to the genus Bacillus and was closely related to Bacillus sporothermodurans DSM 10599(T) and Bacillus oleronius DSM 9356(T), with 98.4 and 97.2 % sequence similarity, respectively. The DNA-DNA hybridization values between strain LAM0415(T) and the two reference strains were 33.3 ± 1.2 and 42.8 ± 0.8 %, respectively. The genomic DNA G+C content was 35.2 mol% as determined by the T m method. The major fatty acids were determined to be iso-C15:0, anteiso-C15:0 and anteiso-C17:0. The predominant menaquinones were identified as MK7 and MK8. The major polar lipids were found to be diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid and four unidentified glycolipids. The diagnostic amino acid of the cell wall peptidoglycan was determined to be meso-diaminopimelic acid. On the basis of its phenotypic, phylogenetic and chemotaxonomic characteristics, strain LAM0415(T) (=ACCC 06413(T) = JCM 19841(T)) represents the type strain of a novel species of the genus Bacillus, for which the name Bacillus vini sp. nov. is proposed.

  13. Development of alcoholic and malolactic fermentations in highly acidic and phenolic apple musts.

    Science.gov (United States)

    del Campo, Gloria; Berregi, Iñaki; Santos, José Ignacio; Dueñas, Maite; Irastorza, Ana

    2008-05-01

    This work reports the influence of the high acidity and high phenolic content in apple musts on the development of alcoholic and malolactic fermentations and on the final chemical and microbiological composition of the ciders. Four different musts were obtained by pressing several varieties and proportions of cider apples from the Basque Country (Northern Spain). Specially acidic and phenolic varieties were selected. Three musts were obtained in experimental stations and the fourth one, in a cider factory following usual procedures. The evolution of these musts was monitored during five months by measuring 18 parameters throughout eight samplings. In the most acidic of the three experimental musts, yeasts were added to complete the alcoholic fermentation. In the rest of the musts, alcoholic and malolactic fermentations took place spontaneously due to natural microflora and no chemical was added to control these processes. Malolactic fermentation (MLF) finished before alcoholic fermentation in the three tanks obtained in experimental stations, even in the most acidic and phenolic one (pH 3.18, 1.78 g tannic acid/l). After four months, these ciders maintained low levels of lactic acid bacteria (10(4)CFU/ml) and low content of acetic acid (cider factory, but MLF finished 10 days after alcoholic fermentation. Subsequently, this must maintained a high population of lactic acid bacteria (>10(6)CFU/ml), causing a higher production of acetic acid (>1.00 g/l) than in the other ciders. These results show the possible advantages of MLF finishing before alcoholic fermentation.

  14. Determination of Ethyl Carbamate in Alcoholic Beverages and Fermented Foods Sold in Korea

    Science.gov (United States)

    Ryu, Dayeon; Choi, Bogyoung; Kim, Eunjoo; Park, Seri; Paeng, Hwijin; Kim, Cho-il; Lee, Jee-yeon; Yoon, Hae Jung

    2015-01-01

    Ethyl carbamate (EC) classified as a probable human carcinogen (Group 2A) is naturally formed in alcoholic beverages and fermented foods during fermentation process and/or during storage. The objective of this study was to analyze EC in 34 food items including 14 alcoholic beverages and 20 fermented foods sold in Korea. Each food was collected from 18 supermarkets in 9 metropolitan cities in Korea, and then made into composite. According to food composition and alcohol content, samples were divided into four matrices such as apple juice, milk, Soju (liquor containing about 20% alcohol), and rice porridge. The maximum EC value of 151.06 µg/kg was found in Maesilju (liquor made from Maesil and Soju). Whisky and Bokbunjaju (Korean black raspberry wine) contained 9.90 µg/kg and 6.30 µg/kg, respectively. EC was not detected in other alcoholic beverages. Of 20 fermented foods, Japanese-style soy sauce had highest level of 15.59 µg/kg and traditional one contained 4.18 µg/kg. Soybean paste had 1.18 µg/kg, however, EC was not found in other fermented foods. PMID:26483888

  15. Modeling of Clostridium t yrobutyricum for Butyric Acid Selectivity in Continuous Fermentation

    OpenAIRE

    Jianjun Du; Amy McGraw; Jamie A. Hestekin

    2014-01-01

    A mathematical model was developed to describe batch and continuous fermentation of glucose to organic acids with Clostridium tyrobutyricum . A modified Monod equation was used to describe cell growth, and a Luedeking-Piret equation was used to describe the production of butyric and acetic acids. Using the batch fermentation equations, models predicting butyric acid selectivity for continuous fermentation were also developed. The model showed that butyric acid production was a strong function...

  16. Effect of gas sparging on continuous fermentative hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong-Hoon; Kim, Sang-Hyoun; Shin, Hang-Sik [Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Han, Sun-Kee [Department of Environmental Health, Korea National Open University, 169 Dongsung-dong, Jongno-gu, Seoul 110-791 (Korea, Republic of)

    2006-12-15

    The effect of gas sparging on continuous fermentative H{sub 2} production was investigated in completely stirred-tank reactors (CSTR) using internal biogas, N{sub 2} and CO{sub 2} with various flow rates (100, 200, 300 and 400ml/min). The sparging with external gases of N{sub 2} and CO{sub 2} showed higher H{sub 2} yield than the control of no sparging and internal biogas sparging. It indicated that the decrease of H{sub 2} partial pressure by external gas sparging had a beneficial effect on H{sub 2} fermentation. Especially, CO{sub 2} sparging was more effective in the reactor performance than N{sub 2} sparging, accompanied by higher production of H{sub 2} and butyrate. The best performance was obtained by CO{sub 2} sparging at 300ml/min, resulting in the highest H{sub 2} yield of 1.68molH{sub 2}/molhexose{sub consumed} and the maximum specific H{sub 2} production rate of 6.89L H{sub 2}/g VSS/day. Compared to N{sub 2} sparging, there might be another positive effect in CO{sub 2} sparging apart from lowering H{sub 2} partial pressure. High CO{sub 2} partial pressure had little effect on H{sub 2}-producing bacteria but inhibitory effect on other microorganisms such as acetogens and lactic acid bacteria which were competitive with H{sub 2}-producing bacteria. Only H{sub 2}-producing bacteria, such as Clostridium tyrobutyricum, C. proteolyticum and C. acidisoli were isolated under CO{sub 2} sparging conditions based on 16S rDNA analysis by PCR-DGGE. (author)

  17. Procedure of brewing alcohol as a staple food: case study of the fermented cereal liquor “Parshot” as a staple food in Dirashe special woreda, southern Ethiopia

    OpenAIRE

    Sunano, Yui

    2015-01-01

    Abstract For most brews, alcohol fermentation and lactic fermentation take place simultaneously during the brewing process, and alcohol fermentation can progress smoothly because the propagation of various microorganisms is prevented by lactic fermentation. It is not necessary to cause lactic fermentation with a thing generated naturally and intentionally. The people living in the Dirashe area in southern Ethiopia drink three types of alcoholic beverages that are prepared from cereals. From t...

  18. Continued smoking and continued alcohol consumption during early pregnancy distinctively associated with personality

    NARCIS (Netherlands)

    Beijers, C.; Burger, H.; Verbeek, T.; Bockting, C. L. H.; Ormel, J.

    2014-01-01

    Pregnancy is a unique period to quit smoking and alcohol consumption and although motivated, not all women succeed at this. We investigated the associations of personality with continued smoking and continued alcohol consumption during early pregnancy. In addition, we studied whether antenatal anxie

  19. The Effect of Proanthocyanidins on Growth and Alcoholic Fermentation of Wine Yeast under Copper Stress.

    Science.gov (United States)

    Jia, Bo; Liu, Xingyan; Zhan, Jicheng; Li, Jingyuan; Huang, Weidong

    2015-06-01

    Proanthocyanidins (PAs) derived from the grape skin, as well as from grape seeds, grape stems, are an important group of polyphenols in wine. The aim of this study was to understand the effect of PAs (0.1, 1.0 g/L) on growth and alcoholic fermentation of 2 strains of Saccharomyces cerevisiae (commercial strain FREDDO and newly selected strain BH8) during copper-stress fermentation, using a simple model fermentation system. Our results showed that both PAs and Cu(2+) could pose significant inhibition effects on the growth of yeast cells, CO2 release, sugar consumption, and ethanol production during the initial phase of the fermentation. Compared to PAs, Cu(2+) performed more obvious inhibition on the yeast growth and fermentation. However, adding 1.0 g/L PAs increased in the vitality and metabolism activity of yeast cells at the mid-exponential phase of fermentation in the mediums with no copper and 0.1 mM Cu(2+) added, shortened the period of wine fermentation, and decreased the copper residues. It indicated that PAs could improve the ability of wine yeast to resist detrimental effects under copper-stress fermentation condition, maintaining cells metabolic activity, and fermentation could be controlled by manipulating PAs supplementation.

  20. A Traditional Turkish Fermented Non-Alcoholic Grape-Based Beverage, “Hardaliye”

    Directory of Open Access Journals (Sweden)

    Fatma Coskun

    2017-01-01

    Full Text Available Hardaliye is a non-alcoholic fermented beverage produced in a traditional way in Thrace, the European part of Turkey. The nutritional value of hardaliye is derived from the grapes and the fermentation process. Health benefits of hardaliye are also related to etheric oils present in mustard seeds. Hardaliye is a lactic acid fermented traditional beverage produced from grape juice and crushed grapes with the addition of different concentrations of whole/ground or heat-treated mustard seeds and sour cherry leaves. The color of hardaliye reflects the original color of the grapes and has a characteristic aroma. Dark red grape is preferred. Benzoic acid is used as preservative during production. Benzoic acid inhibits or decreases alcohol production by affecting the yeast. Fermentation occurs at room temperature for 7–10 days. If the ambient temperature is low, fermentation process can be extended until 20 days. Once fermented, the hardaliye is stored at 4 °C for three to four months. The hardaliye is consumed either fresh or aged. If it is aged, hardaliye may contain alcohol. The industrial production is just in small-scale and it must be developed. More studies are required to determine characteristic properties of hardaliye. Identification of the product properties will supply improvement for industrial production.

  1. Simultaneous Alcoholic and Malolactic Fermentations by Saccharomyces cerevisiae and Oenococcus oeni Cells Co-immobilized in Alginate Beads

    Science.gov (United States)

    Bleve, Gianluca; Tufariello, Maria; Vetrano, Cosimo; Mita, Giovanni; Grieco, Francesco

    2016-01-01

    Malolactic fermentation (MLF) usually takes place after the end of alcoholic fermentation (AF). However, the inoculation of lactic acid bacteria together with yeast starter cultures is a promising system to enhance the quality and safety of wine. In recent years, the use of immobilized cell systems has been investigated, with interesting results, for the production of different fermented foods and beverages. In this study we have carried out the simultaneous immobilization of Saccharomyces cerevisiae and Oenococcus oeni in alginate beads and used them in microvinifications tests to produce Negroamaro wine. The process was monitored by chemical and sensorial analyses and dominance of starters and cell leaking from beads were also checked. Co-immobilization of S. cerevisiae and O. oeni allowed to perform an efficient fermentation process, producing low volatile acidity levels and ethanol and glycerol concentrations comparable with those obtained by cell sequential inoculum and co-inoculum of yeast and bacteria cells in free form. More importantly, co-immobilization strategy produced a significant decrease of the time requested to complete AF and MLF. The immobilized cells could be efficiently reused for the wine fermentation at least three times without any apparent loss of cell metabolic activities. This integrated biocatalytic system is able to perform simultaneously AF and MLF, producing wines similar in organoleptic traits in comparison with wines fermented following traditional sequential AF and MLF with free cell starters. The immobilized-cell system, that we here describe for the first time in our knowledge, offers many advantages over conventional free cell fermentations, including: (i) elimination of non-productive cell growth phases; (ii) feasibility of continuous processing; (iii) re-use of the biocatalyst. PMID:27379072

  2. Kinetics of volatile metabolites during alcoholic fermentation of cane molasses by Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Cachot, T.; Mueller, M.; Pons, M.N. (Centre National de la Recherche Scientifique, 54 - Nancy (France). Lab. des Sciences du Genie Chimique)

    1991-07-01

    The kinetics of ethanol, acetaldehyde, ethyl acetate and fusel alcohols during alcoholic fermentations on cane molasses by Saccharomyces cerevisiae have been obtained via an in-situ gas membrane sensor connected to a gas chromatograph. Various operation parameters have been investigated such as inoculum rate, molasses concentration, operation mode (batch, fed-batch). The modification of fusel alcohols kinetics in response to addition of amino acids has been studied as well as the assimilation of two intermediary aldehydes (isovaleraldehyde and isobutyraldehyde) in the fusel alcohol synthesis pathway. (orig.).

  3. Continued smoking and continued alcohol consumption during early pregnancy distinctively associated with personality.

    Science.gov (United States)

    Beijers, Chantal; Burger, Huibert; Verbeek, Tjitte; Bockting, Claudi L H; Ormel, Johan

    2014-05-01

    Pregnancy is a unique period to quit smoking and alcohol consumption and although motivated, not all women succeed at this. We investigated the associations of personality with continued smoking and continued alcohol consumption during early pregnancy. In addition, we studied whether antenatal anxiety and depressive symptoms can explain these associations. Two antenatal measurements from the population-based Pregnancy Anxiety and Depression cohort study were used. Pregnant women in their first trimester were recruited via midwifery practices and hospitals. We analyzed a sample of women who continued (n=101) or quit smoking (n=254), and a sample of women who continued (n=110) or quit alcohol consumption (n=1230). Measures included questions about smoking, alcohol consumption, the NEO-Five Factor Inventory (personality), the State Trait Anxiety Inventory, and the Edinburgh Postnatal Depression Scale. We found associations between continued alcohol consumption and higher levels of openness to experience, and lower levels of conscientiousness (psmoking emerged. This study contributes to the limited literature on personality differences between women who continue and quit smoking and alcohol consumption during early pregnancy. General population studies have not confirmed the association between openness to experience and alcohol consumption which implies that pregnancy is indeed a unique period. Increased insight in how personality influences continued smoking and alcohol consumption during pregnancy can help health professionals to improve lifestyle interventions targeted at pregnant women.

  4. Traditional low-alcoholic and non-alcoholic fermented beverages consumed in European countries: a neglected food group.

    Science.gov (United States)

    Baschali, Aristea; Tsakalidou, Effie; Kyriacou, Adamantini; Karavasiloglou, Nena; Matalas, Antonia-Leda

    2017-06-01

    Fermented beverages hold a long tradition and contribution to the nutrition of many societies and cultures worldwide. Traditional fermentation has been empirically developed in ancient times as a process of raw food preservation and at the same time production of new foods with different sensorial characteristics, such as texture, flavour and aroma, as well as nutritional value. Low-alcoholic fermented beverages (LAFB) and non-alcoholic fermented beverages (NAFB) represent a subgroup of fermented beverages that have received rather little attention by consumers and scientists alike, especially with regard to their types and traditional uses in European societies. A literature review was undertaken and research articles, review papers and textbooks were searched in order to retrieve data regarding the dietary role, nutrient composition, health benefits and other relevant aspects of diverse ethnic LAFB and NAFB consumed by European populations. A variety of traditional LAFB and NAFB consumed in European regions, such as kefir, kvass, kombucha and hardaliye, are presented. Milk-based LAFB and NAFB are also available on the market, often characterised as 'functional' foods on the basis of their probiotic culture content. Future research should focus on elucidating the dietary role and nutritional value of traditional and 'functional' LAFB and NAFB, their potential health benefits and consumption trends in European countries. Such data will allow for LAFB and NAFB to be included in national food composition tables.

  5. Copper Tolerance and Biosorption of Saccharomyces cerevisiae during Alcoholic Fermentation.

    Science.gov (United States)

    Sun, Xiang-Yu; Zhao, Yu; Liu, Ling-Ling; Jia, Bo; Zhao, Fang; Huang, Wei-Dong; Zhan, Ji-Cheng

    2015-01-01

    At high levels, copper in grape mash can inhibit yeast activity and cause stuck fermentations. Wine yeast has limited tolerance of copper and can reduce copper levels in wine during fermentation. This study aimed to understand copper tolerance of wine yeast and establish the mechanism by which yeast decreases copper in the must during fermentation. Three strains of Saccharomyces cerevisiae (lab selected strain BH8 and industrial strains AWRI R2 and Freddo) and a simple model fermentation system containing 0 to 1.50 mM Cu2+ were used. ICP-AES determined Cu ion concentration in the must decreasing differently by strains and initial copper levels during fermentation. Fermentation performance was heavily inhibited under copper stress, paralleled a decrease in viable cell numbers. Strain BH8 showed higher copper-tolerance than strain AWRI R2 and higher adsorption than Freddo. Yeast cell surface depression and intracellular structure deformation after copper treatment were observed by scanning electron microscopy and transmission electron microscopy; electronic differential system detected higher surface Cu and no intracellular Cu on 1.50 mM copper treated yeast cells. It is most probably that surface adsorption dominated the biosorption process of Cu2+ for strain BH8, with saturation being accomplished in 24 h. This study demonstrated that Saccharomyces cerevisiae strain BH8 has good tolerance and adsorption of Cu, and reduces Cu2+ concentrations during fermentation in simple model system mainly through surface adsorption. The results indicate that the strain selected from China's stress-tolerant wine grape is copper tolerant and can reduce copper in must when fermenting in a copper rich simple model system, and provided information for studies on mechanisms of heavy metal stress.

  6. Copper Tolerance and Biosorption of Saccharomyces cerevisiae during Alcoholic Fermentation

    Science.gov (United States)

    Liu, Ling-ling; Jia, Bo; Zhao, Fang; Huang, Wei-dong; Zhan, Ji-cheng

    2015-01-01

    At high levels, copper in grape mash can inhibit yeast activity and cause stuck fermentations. Wine yeast has limited tolerance of copper and can reduce copper levels in wine during fermentation. This study aimed to understand copper tolerance of wine yeast and establish the mechanism by which yeast decreases copper in the must during fermentation. Three strains of Saccharomyces cerevisiae (lab selected strain BH8 and industrial strains AWRI R2 and Freddo) and a simple model fermentation system containing 0 to 1.50 mM Cu2+ were used. ICP-AES determined Cu ion concentration in the must decreasing differently by strains and initial copper levels during fermentation. Fermentation performance was heavily inhibited under copper stress, paralleled a decrease in viable cell numbers. Strain BH8 showed higher copper-tolerance than strain AWRI R2 and higher adsorption than Freddo. Yeast cell surface depression and intracellular structure deformation after copper treatment were observed by scanning electron microscopy and transmission electron microscopy; electronic differential system detected higher surface Cu and no intracellular Cu on 1.50 mM copper treated yeast cells. It is most probably that surface adsorption dominated the biosorption process of Cu2+ for strain BH8, with saturation being accomplished in 24 h. This study demonstrated that Saccharomyces cerevisiae strain BH8 has good tolerance and adsorption of Cu, and reduces Cu2+ concentrations during fermentation in simple model system mainly through surface adsorption. The results indicate that the strain selected from China’s stress-tolerant wine grape is copper tolerant and can reduce copper in must when fermenting in a copper rich simple model system, and provided information for studies on mechanisms of heavy metal stress. PMID:26030864

  7. New insight into microbial diversity and functions in traditional Vietnamese alcoholic fermentation.

    Science.gov (United States)

    Thanh, Vu Nguyen; Thuy, Nguyen Thanh; Chi, Nguyen Thuy; Hien, Dinh Duc; Ha, Bui Thi Viet; Luong, Dao Thi; Ngoc, Pham Duc; Ty, Pham Van

    2016-09-02

    The roles of microorganisms in traditional alcoholic fermentation are often assumed based on abundance in the starter and activity in pure culture. There is a serious lack of hard evidence on the behavior and activity of individual microbial species during the actual fermentation process. In this study, microbial succession and metabolite changes during 7days of traditional Vietnamese alcoholic fermentation were monitored. Special attention was devoted to starch degradation. In total, 22 microbial species, including 6 species of filamentous fungi (Rhizopus microsporus, Rhizopus arrhizus, Mucor indicus, Mucor circinelloides, Cunninghamella elegans, Aspergillus niger), 1 yeast-like fungus (Saccharomycopsis fibuligera), 7 yeasts (Saccharomyces cerevisiae, Clavispora lusitaniae, Wickerhamomyces anomalus, Lindnera fabianii, Pichia kudriavzevii, Candida rugosa, Candida tropicalis), and 8 bacteria (Stenotrophomonas maltophilia, Lactobacillus brevis, Lactobacillus helveticus, Acinetobacter baumannii, Staphylococcus hominis, Bacillus megaterium, Enterobacter asburiae, Pediococcus pentosaceus) were identified. Despite the presence of a complex microbiota in the starter, the fermentation process is consistent and involves a limited number of functional species. Rapid change in microbial composition of fermentation mash was observed and it was correlated with ethanol content. Microbial biomass reached maximum during first 2days of solid state fermentation. Acidification of the medium took place in day 1, starch degradation in days 2, 3, 4, and alcohol accumulation from day 3. Although Sm. fibuligera dominated by cell count amongst potential starch degraders, zymography indicated that it did not produce amylase in the fermentation mash. In mixed culture with Rhizopus, amylase production by Sm. fibuligera is regulated by the moisture content of the substrate. Rhizopus was identified as the main starch degrader and S. cerevisiae as the main ethanol producer. Bacterial load was

  8. Optimization of honey-must preparation and alcoholic fermentation by Saccharomyces cerevisiae for mead production.

    Science.gov (United States)

    Mendes-Ferreira, A; Cosme, F; Barbosa, C; Falco, V; Inês, A; Mendes-Faia, A

    2010-11-15

    Mead fermentation is a time-consuming process, often taking several months to complete. Despite of the use of starter cultures several problems still persist such as lack of uniformity of the final products, slow or premature fermentation arrest and the production of off-flavors by yeast. Thus the aim of this study was to optimize mead production through the use of an appropriate honey-must formulation to improve yeast performance alcoholic fermentation and thereby obtain a high quality product. Honey-must was centrifuged to reduce insoluble solids, pasteurized at 65°C for 10 min, and then subjected to different conditions: nitrogen supplementation and addition of organic acids. Although the addition of diammonium phosphate (DAP) reduced fermentation length, it did not guarantee the completeness of the fermentation process, suggesting that other factors could account for the reduced yeast activity in honey-must fermentations. Sixteen yeast-derived aroma compounds which contribute to the sensorial quality of mead were identified and quantified. Global analysis of aromatic profiles revealed that the total concentration of aroma compounds in meads was higher in those fermentations where DAP was added. A positive correlation between nitrogen availability and the levels of ethyl and acetate esters, associated to the fruity character of fermented beverages, was observed whereas the presence of potassium tartrate and malic acid decreased, in general, their concentration. This study provides very useful information that can be used for improving mead quality.

  9. Influence of nitrogen sources on growth and fermentation performance of different wine yeast species during alcoholic fermentation.

    Science.gov (United States)

    Kemsawasd, Varongsiri; Viana, Tiago; Ardö, Ylva; Arneborg, Nils

    2015-12-01

    In this study, the influence of twenty different single (i.e. 19 amino acids and ammonium sulphate) and two multiple nitrogen sources (N-sources) on growth and fermentation (i.e. glucose consumption and ethanol production) performance of Saccharomyces cerevisiae and of four wine-related non-Saccharomyces yeast species (Lachancea thermotolerans, Metschnikowia pulcherrima, Hanseniaspora uvarum and Torulaspora delbrueckii) was investigated during alcoholic fermentation. Briefly, the N-sources with beneficial effects on all performance parameters (or for the majority of them) for each yeast species were alanine, arginine, asparagine, aspartic acid, glutamine, isoleucine, ammonium sulphate, serine, valine and mixtures of 19 amino acids and of 19 amino acids plus ammonium sulphate (for S. cerevisiae), serine (for L. thermotolerans), alanine (for H. uvarum), alanine and asparagine (for M. pulcherrima), arginine, asparagine, glutamine, isoleucine and mixture of 19 amino acids (for T. delbrueckii). Furthermore, our results showed a clear positive effect of complex mixtures of N-sources on S. cerevisiae and on T. delbrueckii (although to a lesser extent) as to all performance parameters studied, whereas for L. thermotolerans, H. uvarum and M. pulcherrima, single amino acids affected growth and fermentation performance to the same extent as the mixtures. Moreover, we found groups of N-sources with similar effects on the growth and/or fermentation performance of two or more yeast species. Finally, the influences of N-sources observed for T. delbrueckii and H. uvarum resembled those of S. cerevisiae the most and the least, respectively. Overall, this work contributes to an improved understanding of how different N-sources affect growth, glucose consumption and ethanol production of wine-related yeast species under oxygen-limited conditions, which, in turn, may be used to, e.g. optimize growth and fermentation performance of the given yeast upon N-source supplementation during

  10. Biomass production and alcoholic fermentation performance of Saccharomyces cerevisiae as a function of nitrogen source.

    Science.gov (United States)

    Martínez-Moreno, Ruben; Morales, Pilar; Gonzalez, Ramon; Mas, Albert; Beltran, Gemma

    2012-06-01

    Nitrogen limitation is one of the most common causes for stuck or sluggish fermentation. A broad range of values have been reported as the minimum nitrogen concentration necessary for the completion of alcoholic fermentation. We have analyzed the minimum nitrogen concentration required to yield the maximum biomass (nitrogen reference value) using a microwell plate reader to monitor fermentation with different nitrogen sources and sugar concentrations. The biomass yield was dependent on the amount of available nitrogen, the nature of nitrogen source, and the sugar concentration in the medium. Nevertheless, achieving the maximum biomass was not sufficient to ensure the completion of the alcoholic fermentation, because the fermentation of 280 g sugar L(-1) stuck, regardless of the nature and concentration of nitrogen source. However, a mixture of five amino acids (Leu, Ile, Val, Phe and Thr) as the nitrogen source allowed for maximum sugar consumption. Analysis of cell vitality by impedance showed a significant improvement in the vitality for cells fermenting using this amino acid combination.

  11. Non-Alcoholic Beverages from Fermented Cereals with Increased Oligosaccharide Content

    Directory of Open Access Journals (Sweden)

    Grazina Juodeikiene

    2016-01-01

    Full Text Available The aim of this study is to develop a new technology for making traditional Lithuanian non-alcoholic beverage kvass from fermented cereals by extending the spectrum of raw materials (extruded rye and applying new biotechnological resources (xylanolytic enzymes and lactic acid bacteria (LAB to improve its functional properties. Arabinoxylans in extruded rye were very efficiently hydrolysed into oligosaccharides by xylanolytic complex Ceremix Plus MG. Using Ceremix Plus MG and LAB fermentation, the yield of arabinoxylooligosaccharides and xylooligosaccharides in beverage was increased to 300 and 1100 mg/L, respectively. Beverages fermented by LAB had lower pH values and ethanol volume fraction compared to the yeast-fermented beverage. The acceptability of the beverage fermented by Lactobacillus sakei was higher than of Pediococcus pentosaceus- or yeast-fermented beverages and similar to the acceptability of commercial kvass made from malt extract. The results showed that extruded rye, xylanolytic enzymes and LAB can be used for production of novel and safe high-value non-alcoholic beverages.

  12. Influence of Candida pulcherrima Patagonian strain on alcoholic fermentation behaviour and wine aroma.

    Science.gov (United States)

    Rodríguez, María Eugenia; Lopes, Christian A; Barbagelata, Raúl J; Barda, Nora B; Caballero, Adriana C

    2010-03-31

    The use of selected Saccharomyces and non-Saccharomyces strains as mixed starters in winemaking would have advantages over the traditional spontaneous fermentation, producing wines with predictable and desirable characteristics. The aim of this study was to evaluate the impact of metabolic interactions between Patagonian indigenous Saccharomyces cerevisiae MMf9 and beta-glucosidase producer Candida pulcherrima V(6) strains on alcoholic fermentation behaviour and wine aroma Three inoculation strategies, simultaneous, sequential and final, were assayed at laboratory-scale fermentations using Muscat d'Alexandrie grape juice as substrate. The fermentation and yeast growth kinetics as well as the physicochemical and the sensory quality of wine were evaluated. Results evidenced that the sequential inoculation is the most adequate strategy of strains combination. The kinetic behaviour of sequential fermentation was similar to a successful spontaneous fermentation and its wine showed differential aromatic quality as evidenced through PC analysis using physicochemical and aromatic composition data. This wine presented the highest total concentration of higher alcohol, esters and terpenols and the strongest fruity and floral aroma.

  13. Effects of ADH2 overexpression in Saccharomyces bayanus during alcoholic fermentation.

    Science.gov (United States)

    Maestre, Oscar; García-Martínez, Teresa; Peinado, Rafael A; Mauricio, Juan C

    2008-02-01

    The effect of overexpression of the gene ADH2 on metabolic and biological activity in Saccharomyces bayanus V5 during alcoholic fermentation has been evaluated. This gene is known to encode alcohol dehydrogenase II (ADH II). During the biological aging of sherry wines, where yeasts have to grow on ethanol owing to the absence of glucose, this isoenzyme plays a prominent role by converting the ethanol into acetaldehyde and producing NADH in the process. Overexpression of the gene ADH2 during alcoholic fermentation has no effect on the proteomic profile or the net production of some metabolites associated with glycolysis and alcoholic fermentation such as ethanol, acetaldehyde, and glycerol. However, it affects indirectly glucose and ammonium uptakes, cell growth, and intracellular redox potential, which lead to an altered metabolome. The increased contents in acetoin, acetic acid, and L-proline present in the fermentation medium under these conditions can be ascribed to detoxification by removal of excess acetaldehyde and the need to restore and maintain the intracellular redox potential balance.

  14. Continuous Cellulosic Bioethanol Fermentation by Cyclic Fed-Batch Cocultivation

    Science.gov (United States)

    Jiang, He-Long; He, Qiang; He, Zhili; Hemme, Christopher L.; Wu, Liyou

    2013-01-01

    Cocultivation of cellulolytic and saccharolytic microbial populations is a promising strategy to improve bioethanol production from the fermentation of recalcitrant cellulosic materials. Earlier studies have demonstrated the effectiveness of cocultivation in enhancing ethanolic fermentation of cellulose in batch fermentation. To further enhance process efficiency, a semicontinuous cyclic fed-batch fermentor configuration was evaluated for its potential in enhancing the efficiency of cellulose fermentation using cocultivation. Cocultures of cellulolytic Clostridium thermocellum LQRI and saccharolytic Thermoanaerobacter pseudethanolicus strain X514 were tested in the semicontinuous fermentor as a model system. Initial cellulose concentration and pH were identified as the key process parameters controlling cellulose fermentation performance in the fixed-volume cyclic fed-batch coculture system. At an initial cellulose concentration of 40 g liter−1, the concentration of ethanol produced with pH control was 4.5-fold higher than that without pH control. It was also found that efficient cellulosic bioethanol production by cocultivation was sustained in the semicontinuous configuration, with bioethanol production reaching 474 mM in 96 h with an initial cellulose concentration of 80 g liter−1 and pH controlled at 6.5 to 6.8. These results suggested the advantages of the cyclic fed-batch process for cellulosic bioethanol fermentation by the cocultures. PMID:23275517

  15. Behavior of a fenhexamid photoproduct during the alcoholic fermentation of Saccharomyces cerevisiae.

    Science.gov (United States)

    Cabras, Paolo; Farris, Giovanni A; Pinna, Maria V; Pusino, Alba

    2004-12-29

    The fungicide fenhexamid [N-(2,3-dichloro-4-hydroxyphenyl)-1-methylcyclohexanecarboxamide] degraded rapidly by UV or sunlight irradiation, yielding 7-chloro-6-hydroxy-2-(1-methylcyclohexyl)-1,3-benzoxazole (CHB) as a main photoproduct. CHB was isolated, and its effect on alcoholic fermentation of Saccharomyces cerevisiae was studied. The results indicate that the presence of CHB does not affect the extent of alcohol production. After 12 days, the amount of CHB in the fermentation medium decreased by ca. 65%. Only 25% of the missing CHB was recovered unchanged from yeasts, most likely because it was adsorbed on the yeast wall cell. The remaining part degraded during the fermentation process. Glucan and chitin, two potential adsorbents, which constitute yeast cell walls, exhibited affinity for CHB.

  16. The Energy Relationships of Corn Production and Alcohol Fermentation.

    Science.gov (United States)

    Van Koevering, Thomas E.; And Others

    1987-01-01

    Proposes that the production of alcohol from corn be used as a practical application of scientific principles that deal with energy transformations. Discusses the solar energy available for growth, examining the utilization of solar energy by plants. Describes the conversion of corn to alcohol, with suggestions for classroom and laboratory study.…

  17. Accelerated alcoholic fermentation caused by defective gene expression related to glucose derepression in Saccharomyces cerevisiae.

    Science.gov (United States)

    Watanabe, Daisuke; Hashimoto, Naoya; Mizuno, Megumi; Zhou, Yan; Akao, Takeshi; Shimoi, Hitoshi

    2013-01-01

    Sake yeast strains maintain high fermentation rates, even after the stationary growth phase begins. To determine the molecular mechanisms underlying this advantageous brewing property, we compared the gene expression profiles of sake and laboratory yeast strains of Saccharomyces cerevisiae during the stationary growth phase. DNA microarray analysis revealed that the sake yeast strain examined had defects in expression of the genes related to glucose derepression mediated by transcription factors Adr1p and Cat8p. Furthermore, deletion of the ADR1 and CAT8 genes slightly but statistically significantly improved the fermentation rate of a laboratory yeast strain. We also identified two loss-of-function mutations in the ADR1 gene of existing sake yeast strains. Taken together, these results indicate that the gene expression program associated with glucose derepression for yeast acts as an impediment to effective alcoholic fermentation under glucose-rich fermentative conditions.

  18. Potentialities and limitations of direct alcoholic fermentation of starchy material with amylolytic yeasts

    Energy Technology Data Exchange (ETDEWEB)

    Mot, R. de; Dijck, K. van; Donkers, A.; Verachtert, H.

    1985-07-01

    The fermentation characteristics of a large number of starch-degrading yeasts were compared. None of the amylolytic yeasts currently recognized, appear to be entirely suitable for direct alcoholic fermentation of starchy biomass. The species capable of extensive starch hydrolysis produce only low amounts of ethanol from glucose and dextrin, one of the major limitations being their low ethanol tolerances. Some of the less-active yeasts have much better glucose-fermentation characteristics, but dextrin conversion is limited probably due to the nature of their enzyme systems. Using an ..cap alpha..-amylase dextrin (22.5% w/v), ethanol yields of about 70% were obtained with Saccharomyces diastaticus strains. Through associative fermentation of S. diastaticus and other selected amylolytic yeasts slightly better yields, however not exceeding 80%, were obtained.

  19. Continuous butanol fermentation and feed starch retrogradation: butanol fermentation sustainability using Clostridium beijerinckii BA101.

    Science.gov (United States)

    Ezeji, T C; Qureshi, N; Blaschek, H P

    2005-01-26

    Use of starch solution as feed for butanol bioconversion processes employing Clostridium beijerinckii BA101 may have added economic advantage over the use of glucose. Acetone butanol ethanol (ABE) was produced from 30 gL(-1) starch solution using a continuous process. The bioreactor was fed at a dilution rate of 0.02 h(-1) and starch solution/feed volume (3 L) was replaced every 72 h. The continuous reactor fed with cornstarch solution (feed temperature 19 degrees C) produced approximately 6.0 gL(-1) total ABE. Increasing the feed storage temperature to 37 degrees C improved ABE production to 7.2 gL(-1) suggesting that retrogradation was occurring more rapidly at 19 degrees C. In both these cases the fermentation drifted toward acid production after approximately 260 h, consistent with the retrogradation of starch overtime. The use of soluble starch, which is less prone to retrogradation, resulted in the production of 9.9 gL(-1) ABE at 37 degrees C feed storage temperature, as compared to 7.2 gL(-1) ABE when cornstarch was used. It should be noted that gelatinized starch retrogradation takes place after sterilization and prior to use of the feed medium, and does not occur during long-term storage of the raw corn material in the months leading up to processing. The degree of hydrolysis of gelatinized starch decreased from 68.8 to 56.2% in 3 days when stored at 37 degrees C. Soluble starch which does not retrograde demonstrated no change in the degree of hydrolysis.

  20. Effect of air supplement on the performance of continuous ethanol fermentation system.

    Science.gov (United States)

    Ryu, D D; Kim, Y J; Kim, J H

    1984-01-01

    For the purpose of improving ethanol productivity, the effect of air supplement on the performance of continuous ethanol fermentation system was studied. The effect of oxygen supplement on yeast concentration, cell yield, cell viability, extracellular ethanol concentration, ethanol yield, maintenance coefficient, specific rates of glucose assimilation, ethanol production, and ethanol productivity have been evaluated, using a high alcohol tolerant Saccharomyces cerevisiae STV89 strain and employing a continuous fermentor equipped with an accurate air metering system in the flow rate range 0-11 mL air/L/h. It was found that, when a small amount of oxygen up to about 80mu mol oxygen/L/h was supplied, the ethanol productivity was significantly enhanced as compared to the productivity of the culture without any air supplement. It was also found that the oxygen supplement improved cell viability considerably as well as the ethanol tolerance level of yeast. As the air supply rate was increased, from 0 to 11 mL air/L/h while maintaining a constant dilution rate at about 0.06 h(-1), the cell concentration increased from 2.3 to 8.2 g/L and the ethanol productivity increased from 1.7 to 4.1 g ethanol/L/h, although the specific ethanol production rate decreased slightly from 0.75 to 0.5 g ethanol/g cell/h. The ethanol yield was slightly improved also with an increase in air supply rate, from about 0.37 to 0.45 ethanol/g glucose. The maintenance coefficient increased by only a small amount with the air supplement. This kind of air supplement technique may very well prove to be of practical importance to a development of a highly productive ethanol fermentation process system especially as a combined system with a high density cell culture technique.

  1. Characteristics of Saccharomyces cerevisiae yeasts exhibiting rough colonies and pseudohyphal morphology with respect to alcoholic fermentation.

    Science.gov (United States)

    Reis, Vanda Renata; Bassi, Ana Paula Guarnieri; da Silva, Jessica Carolina Gomes; Ceccato-Antonini, Sandra Regina

    2013-12-01

    Among the native yeasts found in alcoholic fermentation, rough colonies associated with pseudohyphal morphology belonging to the species Saccharomyces cerevisiae are very common and undesirable during the process. The aim of this work was to perform morphological and physiological characterisations of S. cerevisiae strains that exhibited rough and smooth colonies in an attempt to identify alternatives that could contribute to the management of rough colony yeasts in alcoholic fermentation. Characterisation tests for invasiveness in Agar medium, killer activity, flocculation and fermentative capacity were performed on 22 strains (11 rough and 11 smooth colonies). The effects of acid treatment at different pH values on the growth of two strains ("52"--rough and "PE-02"--smooth) as well as batch fermentation tests with cell recycling and acid treatment of the cells were also evaluated. Invasiveness in YPD Agar medium occurred at low frequency; ten of eleven rough yeasts exhibited flocculation; none of the strains showed killer activity; and the rough strains presented lower and slower fermentative capacities compared to the smooth strains in a 48-h cycle in a batch system with sugar cane juice. The growth of the rough strain was severely affected by the acid treatment at pH values of 1.0 and 1.5; however, the growth of the smooth strain was not affected. The fermentative efficiency in mixed fermentation (smooth and rough strains in the same cell mass proportion) did not differ from the efficiency obtained with the smooth strain alone, most likely because the acid treatment was conducted at pH 1.5 in a batch cell-recycle test. A fermentative efficiency as low as 60% was observed with the rough colony alone.

  2. Characteristics of Saccharomyces cerevisiae yeasts exhibiting rough colonies and pseudohyphal morphology with respect to alcoholic fermentation

    Directory of Open Access Journals (Sweden)

    Vanda Renata Reis

    2013-12-01

    Full Text Available Among the native yeasts found in alcoholic fermentation, rough colonies associated with pseudohyphal morphology belonging to the species Saccharomyces cerevisiae are very common and undesirable during the process. The aim of this work was to perform morphological and physiological characterisations of S. cerevisiae strains that exhibited rough and smooth colonies in an attempt to identify alternatives that could contribute to the management of rough colony yeasts in alcoholic fermentation. Characterisation tests for invasiveness in Agar medium, killer activity, flocculation and fermentative capacity were performed on 22 strains (11 rough and 11 smooth colonies. The effects of acid treatment at different pH values on the growth of two strains ("52" -rough and "PE-02" smooth as well as batch fermentation tests with cell recycling and acid treatment of the cells were also evaluated. Invasiveness in YPD Agar medium occurred at low frequency; ten of eleven rough yeasts exhibited flocculation; none of the strains showed killer activity; and the rough strains presented lower and slower fermentative capacities compared to the smooth strains in a 48-h cycle in a batch system with sugar cane juice. The growth of the rough strain was severely affected by the acid treatment at pH values of 1.0 and 1.5; however, the growth of the smooth strain was not affected. The fermentative efficiency in mixed fermentation (smooth and rough strains in the same cell mass proportion did not differ from the efficiency obtained with the smooth strain alone, most likely because the acid treatment was conducted at pH 1.5 in a batch cell-recycle test. A fermentative efficiency as low as 60% was observed with the rough colony alone.

  3. Solid-state fermentation: a continuous process for fungal tannase production.

    Science.gov (United States)

    van de Lagemaat, J; Pyle, D L

    2004-09-30

    Truly continuous solid-state fermentations with operating times of 2-3 weeks were conducted in a prototype bioreactor for the production of fungal (Penicillium glabrum) tannase from a tannin-containing model substrate. Substantial quantities of the enzyme were synthesized throughout the operating periods and (imperfect) steady-state conditions seemed to be achieved soon after start-up of the fermentations. This demonstrated for the first time the possibility of conducting solid-state fermentations in the continuous mode and with a constant noninoculated feed. The operating variables and fermentation conditions in the bioreactor were sufficiently well predicted for the basic reinoculation concept to succeed. However, an incomplete understanding of the microbial mechanisms, the experimental system, and their interaction indicated the need for more research in this novel area of solid-state fermentation.

  4. Promoter engineering of the Saccharomyces cerevisiae RIM15 gene for improvement of alcoholic fermentation rates under stress conditions.

    Science.gov (United States)

    Watanabe, Daisuke; Kaneko, Akie; Sugimoto, Yukiko; Ohnuki, Shinsuke; Takagi, Hiroshi; Ohya, Yoshikazu

    2017-02-01

    A loss-of-function mutation in the RIM15 gene, which encodes a Greatwall-like protein kinase, is one of the major causes of the high alcoholic fermentation rates in Saccharomyces cerevisiae sake strains closely related to Kyokai no. 7 (K7). However, impairment of Rim15p may not be beneficial under more severe fermentation conditions, such as in the late fermentation stage, as it negatively affects stress responses. To balance stress tolerance and fermentation performance, we inserted the promoter of a gluconeogenic gene, PCK1, into the 5'-untranslated region (5'-UTR) of the RIM15 gene in a laboratory strain to achieve repression of RIM15 gene expression in the glucose-rich early stage with its induction in the stressful late stage of alcoholic fermentation. The promoter-engineered strain exhibited a fermentation rate comparable to that of the RIM15-deleted strain with no decrease in cell viability. The engineered strain achieved better alcoholic fermentation performance than the RIM15-deleted strain under repetitive and high-glucose fermentation conditions. These data demonstrated the validity of promoter engineering of the RIM15 gene that governs inhibitory control of alcoholic fermentation. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  5. Responses of Saccharomyces cerevisiae to nitrogen starvation in wine alcoholic fermentation.

    Science.gov (United States)

    Tesnière, Catherine; Brice, Claire; Blondin, Bruno

    2015-09-01

    Nitrogen is an important nutrient in alcoholic fermentation because its starvation affects both fermentation kinetics and the formation of yeast metabolites. In most alcoholic fermentations, yeasts have to ferment in nitrogen-starved conditions, which requires modifications of cell functions to maintain a high sugar flux and enable cell survival for long periods in stressful conditions. In this review, we present an overview of our current understanding of the responses of the wine yeast Saccharomyces cerevisiae to variations of nitrogen availability. Adaptation to nitrogen starvation involves changes in the activity of signaling pathways such as target of rapamycin (TOR) and nitrogen catabolite repression (NCR), which are important for the remodeling of gene expression and the establishment of stress responses. Upon starvation, protein degradation pathways involving autophagy and the proteasome play a major role in nitrogen recycling and the adjustment of cellular activity. Recent progress in the understanding of the role of these mechanisms should enable advances in fermentation management and the design of novel targets for the selection or improvement of yeast strains.

  6. New approaches to the kinetic study of alcoholic fermentation by chromatographic techniques.

    Science.gov (United States)

    Lainioti, Georgia Ch; Karaiskakis, George

    2013-09-01

    The kinetics of the fermentation process has gained increasing interest, not only in the scientific community, but in the industrial world as well. Information concerning the improvement of batch fermentation performance may potentially be valuable for the designing of scale-up processes. Intensive studies have been conducted with the use of various chromatographic techniques, such as conventional gas chromatography, reversed-flow gas chromatography (RFGC), high-performance liquid chromatography, field-flow fractionation and others. In the present study, specific focus is placed on the employment of RFGC, a method that can successfully be applied for the determination of physicochemical quantities, such as reaction rate constants and activation energies, at each phase of the alcoholic fermentation. In contrast to conventional chromatographic techniques, RFGC can lead to substantial information referring to the evaluation of fermentation kinetics at any time of the process. Moreover, gravitational field-flow fractionation, a sub-technique of field-flow fractionation, presents the ability to monitor the proliferation of Saccharomyces cerevisiae cells through their elution profiles that can be related to the different cell growth stages. The combination of the two techniques can provide important information for kinetic study and the distinction of the growth phases of yeast cell proliferation during alcoholic fermentations conducted under different environmental conditions.

  7. 2,3-Butanediol recovery from fermentation broth by alcohol precipitation and vacuum distillation.

    Science.gov (United States)

    Jeon, Sangjun; Kim, Duk-Ki; Song, Hyohak; Lee, Hee Jong; Park, Sunghoon; Seung, Doyoung; Chang, Yong Keun

    2014-04-01

    This study presents a new and effective downstream process to recover 2,3-butanediol (2,3-BD) from fermentation broth which is produced by a recombinant Klebsiella pneumoniae strain. The ldhA-deficient K. pneumoniae strain yielded about 90 g/L of 2,3-BD, along with a number of by-products, such as organic acids and alcohols, in a 65 h fed-batch fermentation. The pH-adjusted cell-free fermentation broth was firstly concentrated until 2,3-BD reached around 500 g/L by vacuum evaporation at 50°C and 50 mbar vacuum pressure. The concentrated solution was further treated using light alcohols, including methanol, ethanol, and isopropanol, for the precipitation of organic acids and inorganic salts. Isopropanol showed the highest removal efficiency, in which 92.5% and 99.8% of organic acids and inorganic salts were precipitated, respectively. At a final step, a vacuum distillation process enabled the recovery of 76.2% of the treated 2,3-BD, with 96.1% purity, indicating that fermentatively produced 2,3-BD is effectively recovered by a simple alcohol precipitation and vacuum distillation. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  8. Cashew wine vinegar production: alcoholic and acetic fermentation

    Directory of Open Access Journals (Sweden)

    M. E. Silva

    2007-06-01

    Full Text Available Cashew wine of demi-sec grade was produced in a stirred batch reactor. The kinetic parameters obtained for cashew wine fermentation were Y X/S=0.061, Y P/S=0.3 and µmax=0.16 h-1. The yield and the productivity of cashew wine were 57.7% and 0.78 g/Lh respectively. A 2² factorial experimental design was used for the cashew wine vinegar fermentation optimization study. The cashew wine vinegar process optimization ranges found for initial concentrations of ethanol and acetic acid as independent variables were 4.8 to 6.0% and 1.0 to 1.3% respectively.

  9. Acetone-butanol-ethanol fermentation in a continuous and closed-circulating fermentation system with PDMS membrane bioreactor.

    Science.gov (United States)

    Chen, Chunyan; Xiao, Zeyi; Tang, Xiaoyu; Cui, Haidi; Zhang, Junqing; Li, Weijia; Ying, Chao

    2013-01-01

    Acetone-butanol-ethanol (ABE) fermentation by combining a PDMS membrane bioreactor and Clostridium acetobutylicum was studied, and a long continuous and closed-circulating fermentation (CCCF) system has been achieved. Two cycles of experiment were conducted, lasting for 274 h and 300 h, respectively. The operation mode of the first cycle was of fermentation intermittent coupling with pervaporation, and the second cycle was of continuous coupling. The average cell weight, glucose consumption rate, butanol productivity and butanol production of the first cycle were 1.59 g L(-1), 0.63 g L(-1)h(-1), 0.105 g L(-1)h(-1) and 28.03 g L(-1), respectively. Correspondingly, the four parameters of the second cycle were 1.68 g L(-1), 1.12 g L(-1)h(-1), 0.205 g L(-1)h(-1) and 61.43 g L(-1), respectively. The results indicate the fermentation behaviors under continuous coupling mode were superior to that under intermittent coupling mode. Besides, two peak values were observed in the time course profiles, which means the microorganism could adapt the long CCCF membrane bioreactor system. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. STUDY ON ALCOHOLIC FERMENTATION IN A STATIONARY BASKET BIOREACTOR WITH IMMOBILIZED YEAST CELLS

    Directory of Open Access Journals (Sweden)

    Dan Caşcaval

    2011-02-01

    Full Text Available The use of a stationary basket bioreactor with immobilized S. cerevisiae cells indicated the possibility to extend the number of alcoholic fermentation cycles that can be carried out with the same biocatalysts to over nine. Although the rates of glucose consumption and ethanol production were lower than those recorded for the mobile beds of immobilized yeast cells, the mechanical lysis of the biocatalysts is avoided in the case of basket bed. Due to the substrate and product accumulation inside the basket bed, the fermentation process can be improved by washing out the biocatalysts bed over two or four cycles.

  11. Inhibitory activity of carbonyl compounds on alcoholic fermentation by Saccharomyces cerevisiae.

    Science.gov (United States)

    Cao, Dongxu; Tu, Maobing; Xie, Rui; Li, Jing; Wu, Yonnie; Adhikari, Sushil

    2014-01-29

    Aldehydes and acids play important roles in the fermentation inhibition of biomass hydrolysates. A series of carbonyl compounds (vanillin, syringaldehyde, 4-hydroxybenzaldehyde, pyrogallol aldehyde, and o-phthalaldehyde) were used to examine the quantitative structure-inhibitory activity relationship of carbonyl compounds on alcoholic fermentation, based on the glucose consumption rate and the final ethanol yield. It was observed that pyrogallol aldehyde and o-phthalaldehyde (5.0 mM) reduced the initial glucose consumption rate by 60 and 89%, respectively, and also decreased the final ethanol yield by 60 and 99%, respectively. Correlating the molecular descriptors to inhibition efficiency in yeast fermentation revealed a strong relationship between the energy of the lowest unoccupied molecular orbital (ELUMO) of aldehydes and their inhibitory efficiency in fermentation. On the other hand, vanillin, syringaldehyde, and 4-hydroxybenzaldehyde (5.0 mM) increased the final ethanol yields by 11, 4, and 1%, respectively. Addition of vanillin appeared to favor ethanol formation over glycerol formation and decreased the glycerol yield in yeast fermentation. Furthermore, alcohol dehydrogenase (ADH) activity dropped significantly from 3.85 to 2.72, 1.83, 0.46, and 0.11 U/mg at 6 h of fermentation at vanillin concentrations of 0, 2.5, 5.0, 10.0, and 25.0 mM correspondingly. In addition, fermentation inhibition by acetic acid and benzoic acid was pH-dependent. Addition of acetate, benzoate, and potassium chloride increased the glucose consumption rate, likely because the salts enhanced membrane permeability, thus increasing glucose consumption.

  12. Study on the Fermentation Technology of High Concentration of Molasses Alcohol Rapid Heating Clarification%高浓度糖蜜快速热澄清发酵酒精技术的研究

    Institute of Scientific and Technical Information of China (English)

    尚红岩; 姚和平; 高亚飞; 徐日益; 郭艺山; 邓文伟; 康劲菊

    2016-01-01

    酒精高浓度发酵能够提高发酵醪液含酒分,可以节省酒精蒸馏蒸汽消耗量,减少酒精废醪液排放量,提高设备利用率,日益受到酒精生产企业的重视。目前糖蜜酒精生产发酵含酒分普遍偏低,糖蜜高浓度发酵面临很大困难,笔者认为主要原因是糖蜜中的灰分和胶体等杂质含量不断增高,会抑制酵母的繁殖和发酵,影响糖蜜高浓度发酵酒精。对糖蜜进行澄清处理是实现糖蜜酒精浓醪发酵的快捷途径,通过对糖蜜快速热澄清处理,得到糖蜜高浓度发酵酒精,与传统糖蜜酸化后发酵酒精相比,发酵含酒分明显提高,发酵成熟醪锤度降低。%High concentrations of alcohol fermentation could improve fermentation ethanol contents, save alcohol distillation steam consumption, reduce waste liquor of alcohol, and improve the utilization rate of equipment. It had been paid more attention by alcohol production enterprises. The content of alcohol fermentation of molasses alcohol was generally low, so the molasses high concentration fermentation was facing great difficulties. The author thought that the main reason was ash and colloid impurities content in molasses increasing continuously, which could inhibit yeast growth and fermentation and affect the molasses fermentation of high concentration alcohol. The rapid clarification of molasses was a quick way to realize high concentration fermentation of molasses.The high concentration fermentation of molasses alcohol was obtained through the molasses rapid thermal clarification, compared with the traditional acidification fermentation of molasses alcohol, molasses alcohol fermentation liquor with clarification obviously improved, and mature fermented mash brix reduced.

  13. Monitoring and evaluation of alcoholic fermentation processes using a chemocapacitor sensor array.

    Science.gov (United States)

    Oikonomou, Petros; Raptis, Ioannis; Sanopoulou, Merope

    2014-09-02

    The alcoholic fermentation of Savatiano must variety was initiated under laboratory conditions and monitored daily with a gas sensor array without any pre-treatment steps. The sensor array consisted of eight interdigitated chemocapacitors (IDCs) coated with specific polymers. Two batches of fermented must were tested and also subjected daily to standard chemical analysis. The chemical composition of the two fermenting musts differed from day one of laboratory monitoring (due to different storage conditions of the musts) and due to a deliberate increase of the acetic acid content of one of the musts, during the course of the process, in an effort to spoil the fermenting medium. Sensor array responses to the headspace of the fermenting medium were compared with those obtained either for pure or contaminated samples with controlled concentrations of standard ethanol solutions of impurities. Results of data processing with Principal Component Analysis (PCA), demonstrate that this sensing system could discriminate between a normal and a potential spoiled grape must fermentation process, so this gas sensing system could be potentially applied during wine production as an auxiliary qualitative control instrument.

  14. 醋酸发酵辣椒酒精发酵阶段的工艺研究%Alcoholic fermentation technology of acetic-acid fermented chilli

    Institute of Scientific and Technical Information of China (English)

    牛立群; 王修俊; 范志平; 马桂英; 田亮; 曲源

    2011-01-01

    The acetic-acid fermented chilli was produced from fresh red chilli by alcoholic fermentation and acetic fermentation. In this study, the optimal conditions for alcoholic fermentation of acetic-acid fermented chilli were determined as follows: fermentation temperature 291;, initial sugar content 15°Bx, the ratio of yeast to Rhizopus 1:3, inoculum size 6%, and fermentation time 48h. Under above conditions, the alcohol content could reach 6.70%vol.%醋酸发酵辣椒的工艺过程包括酒精发酵和醋酸发酵.该文主要研究确定了醋酸发酵辣椒生产过程中酒精发酵的最佳工艺参数,即发酵温度29℃,初始糖度为15°Bx,接种酵母:根霉比例为1∶3,接种量6%,发酵时间48h,在此条件下酒精度可以达到6.70%vol.

  15. Assessing optimal fermentation type for bio-hydrogen production in continuous-flow acidogenic reactors.

    Science.gov (United States)

    Ren, N Q; Chua, H; Chan, S Y; Tsang, Y F; Wang, Y J; Sin, N

    2007-07-01

    In this study, the optimal fermentation type and the operating conditions of anaerobic process in continuous-flow acidogenic reactors was investigated for the maximization of bio-hydrogen production using mixed cultures. Butyric acid type fermentation occurred at pH>6, propionic acid type fermentation occurred at pH about 5.5 with E(h) (redox potential) >-278mV, and ethanol-type fermentation occurred at pHhydrogen production capacities between the fermentation types, which remained stable when the organic loading rate (OLR) reached the highest OLR at 86.1kgCOD/m(3)d. The maximum hydrogen production reached up to 14.99L/d.

  16. Development of High-Productivity Continuous Ethanol Production using PVA-Immobilized Zymomonas mobilis in an Immobilized-Cells Fermenter

    Directory of Open Access Journals (Sweden)

    Nurhayati Nurhayati

    2015-07-01

    Full Text Available Ethanol as one of renewable energy was being considered an excellent alternative clean-burning fuel to replace gasoline. Continuous ethanol fermentation systems had offered important economic advantages compared to traditional systems. Fermentation rates were significantly improved, especially when continuous fermentation was integrated with cell immobilization techniques to enrich the cells concentration in fermentor. Growing cells of Zymomonas mobilis immobilized in polyvinyl alcohol (PVA gel beads were employed in an immobilized-cells fermentor for continuous ethanol fermentation from glucose. The glucose loading, dilution rate, and cells loading were varied in order to determine which best condition employed in obtaining both high ethanol production and low residual glucose with high dilution rate. In this study, 20 g/L, 100 g/L, 125 g/L and 150 g/L of glucose concentration and 20% (w/v, 40% (w/v and 50% (w/v of cells loading were employed with range of dilution rate at 0.25 to 1 h-1. The most stable production was obtained for 25 days by employing 100 g/L of glucose loading. Meanwhile, the results also exhibited that 125 g/L of glucose loading as well as 40% (w/v of cells loading yielded high ethanol concentration, high ethanol productivity, and acceptable residual glucose at 62.97 g/L, 15.74 g/L/h and 0.16 g/L, respectively. Furthermore, the dilution rate of 4 hour with 100 g/L and 40% (w/v of glucose and cells loading was considered as the optimum condition with ethanol production, ethanol productivity and residual glucose obtained were 49.89 g/L, 12.47 g/L/h, and 2.04 g/L, respectively. This recent study investigated ethanol inhibition as well. The present research had proved that high sugar concentration was successfully converted to ethanol. These achieved results were promising for further study.

  17. Impact of assimilable nitrogen availability in glucose uptake kinetics in Saccharomyces cerevisiae during alcoholic fermentation

    Science.gov (United States)

    2012-01-01

    Background The expression and activity of the different Saccharomyces cerevisiae hexose uptake systems (Hxt) and the kinetics of glucose uptake are considered essential to industrial alcoholic fermentation performance. However, the dynamics of glucose uptake kinetics during the different stages of fermentation, depending on glucose and nitrogen availability, is very poorly characterized. The objective of the present work was to examine thoroughly the alterations occurring in glucose uptake kinetics during alcoholic fermentation, by the wine strain S. cerevisiae PYCC 4072, of a synthetic grape juice basal medium with either a limiting or non-limiting initial nitrogen concentration and following nitrogen supplementation of the nitrogen-depleted sluggish fermentation. Results Independently of the initial concentration of the nitrogen source, glucose transport capacity is maximal during the early stages of fermentation and presumably sustained by the low-affinity and high-capacity glucose transporter Hxt1p. During nitrogen-limited sluggish fermentation, glucose uptake capacity was reduced to approximately 20% of its initial values (Vmax = 4.9 ± 0.8 compared to 21.9 ± 1.2 μmol h-1 10-8 cells), being presumably sustained by the low-affinity glucose transporter Hxt3p (considering the calculated Km = 39.2 ± 8.6 mM). The supplementation of the sluggish fermentation broth with ammonium led to the increase of glucose transport capacity associated to the expression of different glucose uptake systems with low and high affinities for glucose (Km = 58.2 ± 9.1 and 2.7 ± 0.4 mM). A biclustering analysis carried out using microarray data, previously obtained for this yeast strain transcriptional response to equivalent fermentation conditions, indicates that the activation of the expression of genes encoding the glucose transporters Hxt2p (during the transition period to active fermentation) and Hxt3p, Hxt4p, Hxt6p and Hxt7p (during the

  18. Impact of assimilable nitrogen availability in glucose uptake kinetics in Saccharomyces cerevisiae during alcoholic fermentation.

    Science.gov (United States)

    Palma, Margarida; Madeira, Sara Cordeiro; Mendes-Ferreira, Ana; Sá-Correia, Isabel

    2012-07-30

    The expression and activity of the different Saccharomyces cerevisiae hexose uptake systems (Hxt) and the kinetics of glucose uptake are considered essential to industrial alcoholic fermentation performance. However, the dynamics of glucose uptake kinetics during the different stages of fermentation, depending on glucose and nitrogen availability, is very poorly characterized. The objective of the present work was to examine thoroughly the alterations occurring in glucose uptake kinetics during alcoholic fermentation, by the wine strain S. cerevisiae PYCC 4072, of a synthetic grape juice basal medium with either a limiting or non-limiting initial nitrogen concentration and following nitrogen supplementation of the nitrogen-depleted sluggish fermentation. Independently of the initial concentration of the nitrogen source, glucose transport capacity is maximal during the early stages of fermentation and presumably sustained by the low-affinity and high-capacity glucose transporter Hxt1p. During nitrogen-limited sluggish fermentation, glucose uptake capacity was reduced to approximately 20% of its initial values (Vmax = 4.9 ± 0.8 compared to 21.9 ± 1.2 μmol h⁻¹ 10⁻⁸ cells), being presumably sustained by the low-affinity glucose transporter Hxt3p (considering the calculated Km = 39.2 ± 8.6 mM). The supplementation of the sluggish fermentation broth with ammonium led to the increase of glucose transport capacity associated to the expression of different glucose uptake systems with low and high affinities for glucose (Km = 58.2 ± 9.1 and 2.7 ± 0.4 mM). A biclustering analysis carried out using microarray data, previously obtained for this yeast strain transcriptional response to equivalent fermentation conditions, indicates that the activation of the expression of genes encoding the glucose transporters Hxt2p (during the transition period to active fermentation) and Hxt3p, Hxt4p, Hxt6p and Hxt7p (during the period of

  19. Impact of assimilable nitrogen availability in glucose uptake kinetics in Saccharomyces cerevisiae during alcoholic fermentation

    Directory of Open Access Journals (Sweden)

    Palma Margarida

    2012-07-01

    Full Text Available Abstract Background The expression and activity of the different Saccharomyces cerevisiae hexose uptake systems (Hxt and the kinetics of glucose uptake are considered essential to industrial alcoholic fermentation performance. However, the dynamics of glucose uptake kinetics during the different stages of fermentation, depending on glucose and nitrogen availability, is very poorly characterized. The objective of the present work was to examine thoroughly the alterations occurring in glucose uptake kinetics during alcoholic fermentation, by the wine strain S. cerevisiae PYCC 4072, of a synthetic grape juice basal medium with either a limiting or non-limiting initial nitrogen concentration and following nitrogen supplementation of the nitrogen-depleted sluggish fermentation. Results Independently of the initial concentration of the nitrogen source, glucose transport capacity is maximal during the early stages of fermentation and presumably sustained by the low-affinity and high-capacity glucose transporter Hxt1p. During nitrogen-limited sluggish fermentation, glucose uptake capacity was reduced to approximately 20% of its initial values (Vmax = 4.9 ± 0.8 compared to 21.9 ± 1.2 μmol h-1 10-8 cells, being presumably sustained by the low-affinity glucose transporter Hxt3p (considering the calculated Km = 39.2 ± 8.6 mM. The supplementation of the sluggish fermentation broth with ammonium led to the increase of glucose transport capacity associated to the expression of different glucose uptake systems with low and high affinities for glucose (Km = 58.2 ± 9.1 and 2.7 ± 0.4 mM. A biclustering analysis carried out using microarray data, previously obtained for this yeast strain transcriptional response to equivalent fermentation conditions, indicates that the activation of the expression of genes encoding the glucose transporters Hxt2p (during the transition period to active fermentation and Hxt3p, Hxt4p, Hxt6

  20. Alcohol

    Science.gov (United States)

    ... that's how many accidents occur. continue What Is Alcoholism? What can be confusing about alcohol is that ... develop a problem with it. Sometimes, that's called alcoholism (say: al-kuh-HOL - ism) or being an ...

  1. Procedure of brewing alcohol as a staple food: case study of the fermented cereal liquor "Parshot" as a staple food in Dirashe special woreda, southern Ethiopia.

    Science.gov (United States)

    Sunano, Yui

    2016-07-01

    For most brews, alcohol fermentation and lactic fermentation take place simultaneously during the brewing process, and alcohol fermentation can progress smoothly because the propagation of various microorganisms is prevented by lactic fermentation. It is not necessary to cause lactic fermentation with a thing generated naturally and intentionally. The people living in the Dirashe area in southern Ethiopia drink three types of alcoholic beverages that are prepared from cereals. From these alcoholic beverages, parshot is prepared by the addition of plant leaves for lactic fermentation and nech chaka by adding cereal powder for lactic fermentation before alcohol fermentation. People living in the Dirashe area partake of parshot as part of their staple diet. The brewing process used for parshot and a food culture with alcoholic beverages as parts of the staple diet are rare worldwide. This article discusses the significance of using lactic fermentation before alcoholic fermentation and focuses on lactic fermentation in the brewing methods used for the three kinds of alcoholic beverages consumed in the Dirashe area. We initially observed the brewing process and obtained information about the process from the people in that area. Next, we determined the pH and analyzed the lactic acid (g/100 g) and ethanol (g/100 g) content during lactic fermentation of parshot and nech chaka; the ethyl acetate (mg/100 g) and volatile base nitrogen (mg/100 g) content during this period was also analyzed. In addition, we compared the ethanol (g/100 g) content of all three kinds of alcoholic beverages after completion of brewing. The results showed that it was possible to consume large quantities of these alcoholic beverages because of the use of lactic fermentation before alcoholic fermentation, which improved the safety and preservation characteristics of the beverages by preventing the propagation of various microorganisms, improving flavor, and controlling the alcohol level.

  2. Inhibition of beet molasses alcoholic fermentation by lactobacilli

    Energy Technology Data Exchange (ETDEWEB)

    Essia Ngang, J.J.; Letourneau, F.; Wolniewicz, E.; Villa, P. (Amiens Univ., 80 (France). Lab. de Chimie Organique et Cinetique)

    1990-08-01

    Alcohol production rate decreases as the concentration of bacterial contaminants increases. In complex medium, such as beet molasses, an alternative mechanism can be used by homofermentative lactic bacteria (Lactobacillus casei). Lactic acid and associated products, especially acetic acid, are liberated into the medium. The inhibition induced by these metabolites was reinforced by the presence of viable lactobacilli. (orig.).

  3. Selection of an autochthonous Saccharomyces strain starter for alcoholic fermentation of Sherry base wines.

    Science.gov (United States)

    Rodríguez-Palero, María Jesús; Fierro-Risco, Jesús; Codón, Antonio C; Benítez, Tahía; Valcárcel, Manuel J

    2013-06-01

    Several indigenous Saccharomyces strains from musts were isolated in the Jerez de la Frontera region, at the end of spontaneous fermentation, in order to select the most suitable autochthonous yeast starter, during the 2007 vintage. Five strains were chosen for their oenological abilities and fermentative kinetics to elaborate a Sherry base wine. The selected autochthonous strains were characterized by molecular methods: electrophoretic karyotype and random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) and by physiological parameters: fermentative power, ethanol production, sugar consumption, acidity and volatile compound production, sensory quality, killer phenotype, desiccation, and sulphur dioxide tolerance. Laboratory- and pilot-scale fermentations were conducted with those autochthonous strains. One of them, named J4, was finally selected over all others for industrial fermentations. The J4 strain, which possesses exceptional fermentative properties and oenological qualities, prevails in industrial fermentations, and becomes the principal biological agent responsible for winemaking. Sherry base wine, industrially manufactured by means of the J4 strain, was analyzed, yielding, together with its sensory qualities, final average values of 0.9 g/l sugar content, 13.4 % (v/v) ethanol content and 0.26 g/l volatile acidity content; apart from a high acetaldehyde production, responsible for the distinctive aroma of "Fino". This base wine was selected for "Fino" Sherry elaboration and so it was fortified; it is at present being subjected to biological aging by the so-called "flor" yeasts. The "flor" velum formed so far is very high quality. To the best of our knowledge, this is the first study covering from laboratory to industrial scale of characterization and selection of autochthonous starter intended for alcoholic fermentation in Sherry base wines. Since the 2010 vintage, the indigenous J4 strain is employed to industrially manufacture a

  4. Omega-3 production by fermentation of Yarrowia lipolytica: From fed-batch to continuous.

    Science.gov (United States)

    Xie, Dongming; Miller, Edward; Sharpe, Pamela; Jackson, Ethel; Zhu, Quinn

    2017-04-01

    The omega-3 fatty acid, cis-5,8,11,14,17-eicosapentaenoic acid (C20:5; EPA) has wide-ranging benefits in improving heart health, immune function, and mental health. A sustainable source of EPA production through fermentation of metabolically engineered Yarrowia lipolytica has been developed. In this paper, key fed-batch fermentation conditions were identified to achieve 25% EPA in the yeast biomass, which is so far the highest EPA titer reported in the literature. Dynamic models of the EPA fermentation process were established for analyzing, optimizing, and scaling up the fermentation process. In addition, model simulations were used to develop a two-stage continuous process and compare to single-stage continuous and fed- batch processes. The two stage continuous process, which is equipped with a smaller growth fermentor (Stage 1) and a larger production fermentor (Stage 2), was found to be a superior process to achieve high titer, rate, and yield of EPA. A two-stage continuous fermentation experiment with Y. lipolytica strain Z7334 was designed using the model simulation and then tested in a 2 L and 5 L fermentation system for 1,008 h. Compared with the standard 2 L fed-batch process, the two-stage continuous fermentation process improved the overall EPA productivity by 80% and EPA concentration in the fermenter by 40% while achieving comparable EPA titer in biomass and similar conversion yield from glucose. During the long-term experiment it was also found that the Y. lipolytica strain evolved to reduce byproduct and increase lipid production. This is one of the few continuous fermentation examples that demonstrated improved productivity and concentration of a final product with similar conversion yield compared with a fed-batch process. This paper suggests the two-stage continuous fermentation could be an effective process to achieve improved production of omega-3 and other fermentation products where non-growth or partially growth associated kinetics

  5. A Mathematical model for ethanol production by extractive fermentation in a continuous stirred tank fermentor.

    Science.gov (United States)

    Kollerup, F; Daugulis, A J

    1985-09-01

    Extractive fermentation is a technique that can be used to reduce the effect of end product inhibition through the use of a water-immiscible phase that removes fermentation products in situ. This has the beneficial effect of not only removing inhibitory products as they are formed (thus keeping reaction rates high) but also has the potential for reducing product recovery costs. We have chosen to examine the ethanol fermentation as a model system for end product inhibition and extractive fermentation and have developed a computer model predicting the productivity enhancement possible with this technique together with other key parameters such as extraction efficiency and residual glucose concentration. The model accommodates variable liquid flowrates entering and leaving the system, since it was found that the aqueous outlet flowrate could be up to 35% lower than the inlet flowrate during extractive fermentation of concentrated glucose feeds due to the continuous removal of ethanol from the fermentation broth by solvent extraction. The model predicts a total ethanol productivity of 82.6 g/L h if a glucose feed of 750 g/L is fermented with a solvent having a distribution coefficient of 0.5 at a solvent dilution rate of 5.0 h(-1). This is more than 10 times higher than for a conventional chemostat fermentation of a 250 g/L glucose feed. The model has furthermore illustrated the possible trade-offs that exist between obtaining a high extraction efficiency and a low residual glucose concentration.

  6. High‑throughput sequencing of amplicons for monitoring yeast biodiversity in must and during alcoholic fermentation.

    Science.gov (United States)

    David, Vanessa; Terrat, Sébastien; Herzine, Khaled; Claisse, Olivier; Rousseaux, Sandrine; Tourdot-Maréchal, Raphaëlle; Masneuf-Pomarede, Isabelle; Ranjard, Lionel; Alexandre, Hervé

    2014-05-01

    We compared pyrosequencing technology with the PCR-ITS-RFLP analysis of yeast isolates and denaturing gradient gel electrophoresis (DGGE). These methods gave divergent findings for the yeast population. DGGE was unsuitable for the quantification of biodiversity and its use for species detection was limited by the initial abundance of each species. The isolates identified by PCR-ITSRFLP were not fully representative of the true population. For population dynamics, high-throughput sequencing technology yielded results differing in some respects from those obtained with other approaches. This study demonstrates that 454 pyrosequencing of amplicons is more relevant than other methods for studying the yeast community on grapes and during alcoholic fermentation. Indeed, this high-throughput sequencing method detected larger numbers of species on grapes and identified species present during alcoholic fermentation that were undetectable with the other techniques.

  7. Feasibility of using a miniature NIR spectrometer to measure volumic mass during alcoholic fermentation.

    Science.gov (United States)

    Fernández-Novales, Juan; López, María-Isabel; González-Caballero, Virginia; Ramírez, Pilar; Sánchez, María-Teresa

    2011-06-01

    Volumic mass-a key component of must quality control tests during alcoholic fermentation-is of great interest to the winemaking industry. Transmitance near-infrared (NIR) spectra of 124 must samples over the range of 200-1,100-nm were obtained using a miniature spectrometer. The performance of this instrument to predict volumic mass was evaluated using partial least squares (PLS) regression and multiple linear regression (MLR). The validation statistics coefficient of determination (r(2)) and the standard error of prediction (SEP) were r(2) = 0.98, n = 31 and r(2) = 0.96, n = 31, and SEP = 5.85 and 7.49 g/dm(3) for PLS and MLR equations developed to fit reference data for volumic mass and spectral data. Comparison of results from MLR and PLS demonstrates that a MLR model with six significant wavelengths (P alcoholic fermentation, and that a low-cost NIR instrument can be used for this purpose.

  8. Elaboration and characterization of Japanese Raisin Tree (Hovenia dulcis Thumb. pseudofruits fermented alcoholic beverage

    Directory of Open Access Journals (Sweden)

    Juliana Tensol PINTO

    Full Text Available Abstract Hovenia dulcis pseudofruits have underexplored properties for food purposes, despite their pleasant sensory characteristics and therapeutic benefits. The aim of this study was the elaboration and chemical characterization of the alcoholic fermented beverage of H. dulcis, using selected strain of Saccharomyces cerevisiae (CCMA 0200. The resulting fermented beverage presented high content of phenolic compounds and antioxidant activity when compared to other fruits and beverages (DPPH and ABTS assay. The alcohol content was 12.9 oGL and total sugars 3.57g/L. By the GC-MS analysis, 39 compounds were identified including metabolites with therapeutic potential such as eugenol, trans-farnesol salicylates. The flavonoid dihidromyricetin was identified and quantified (75.17 mg/L by HPLC-DAD and UPLC-MS/MS. The results reinforce the interest on nutraceutical and functional properties of this beverage and opens perspectives for new studies that value this underexplored pseudofruit.

  9. Modeling of Clostridium tyrobutyricum for Butyric Acid Selectivity in Continuous Fermentation

    Directory of Open Access Journals (Sweden)

    Jianjun Du

    2014-04-01

    Full Text Available A mathematical model was developed to describe batch and continuous fermentation of glucose to organic acids with Clostridium tyrobutyricum. A modified Monod equation was used to describe cell growth, and a Luedeking-Piret equation was used to describe the production of butyric and acetic acids. Using the batch fermentation equations, models predicting butyric acid selectivity for continuous fermentation were also developed. The model showed that butyric acid production was a strong function of cell mass, while acetic acid production was a function of cell growth rate. Further, it was found that at high acetic acid concentrations, acetic acid was metabolized to butyric acid and that this conversion could be modeled. In batch fermentation, high butyric acid selectivity occurred at high initial cell or glucose concentrations. In continuous fermentation, decreased dilution rate improved selectivity; at a dilution rate of 0.028 h−1, the selectivity reached 95.8%. The model and experimental data showed that at total cell recycle, the butyric acid selectivity could reach 97.3%. This model could be used to optimize butyric acid production using C. tyrobutyricum in a continuous fermentation scheme. This is the first study that mathematically describes batch, steady state, and dynamic behavior of C. tyrobutyricum for butyric acid production.

  10. Examination of protein degradation in continuous flow, microbial electrolysis cells treating fermentation wastewater

    KAUST Repository

    Nam, Joo-Youn

    2014-11-01

    © 2014 Elsevier Ltd. Cellulose fermentation wastewaters (FWWs) contain short chain volatile fatty acids and alcohols, but they also have high concentrations of proteins. Hydrogen gas production from FWW was examined using continuous flow microbial electrolysis cells (MECs), with a focus on fate of the protein. H2 production rates were 0.49±0.05m3/m3-d for the FWW, compared to 0.63±0.02m3/m3-d using a synthetic wastewater containing only acetate (applied potential of 0.9V). Total organic matter removal was 76±6% for the FWW, compared to 87±5% for acetate. The MEC effluent became relatively enriched in protein (69%) compared to that in the original FWW (19%). Protein was completely removed using higher applied voltages (1.0 or 1.2V), but current generation was erratic due to more positive anode potentials (-113±38mV, Eap=1.2V; -338±38mV, 1.0V; -0.426±4mV, 0.9V). Bacteria on the anodes with FWW were primarily Deltaproteobacteria, while Archaea were predominantly Methanobacterium.

  11. Examination of protein degradation in continuous flow, microbial electrolysis cells treating fermentation wastewater.

    Science.gov (United States)

    Nam, Joo-Youn; Yates, Matthew D; Zaybak, Zehra; Logan, Bruce E

    2014-11-01

    Cellulose fermentation wastewaters (FWWs) contain short chain volatile fatty acids and alcohols, but they also have high concentrations of proteins. Hydrogen gas production from FWW was examined using continuous flow microbial electrolysis cells (MECs), with a focus on fate of the protein. H2 production rates were 0.49±0.05 m(3)/m(3)-d for the FWW, compared to 0.63±0.02 m(3)/m(3)-d using a synthetic wastewater containing only acetate (applied potential of 0.9 V). Total organic matter removal was 76±6% for the FWW, compared to 87±5% for acetate. The MEC effluent became relatively enriched in protein (69%) compared to that in the original FWW (19%). Protein was completely removed using higher applied voltages (1.0 or 1.2 V), but current generation was erratic due to more positive anode potentials (-113±38 mV, Eap=1.2V; -338±38 mV, 1.0 V; -0.426±4 mV, 0.9V). Bacteria on the anodes with FWW were primarily Deltaproteobacteria, while Archaea were predominantly Methanobacterium. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Outcome of alcohol dependence: The role of continued care

    Directory of Open Access Journals (Sweden)

    Murthy Pratima

    2009-01-01

    Full Text Available Aims: This study attempted to determine the effects of continued care on subjects with alcohol dependence. Materials and Methods: Study patients were recruited from a slum in Bangalore. The control group comprised individuals from a lower socio-economic status. Both groups received identical treatment from a specialised de-addiction facility. The study group also received weekly continued care in the community, either at a clinic located within the slum or through home visits. Those patients without stable jobs were referred for employment. The control group was given routine hospital follow-up visits. Both groups were evaluated on the Alcohol Problem Questionnaire and quantity/frequency of drinking at baseline and every 3 month interval for one year after discharge. Results: Both groups showed improvement in terms of reduction of drinking at 3 months, with the study group showing a 64% improvement with respect to the number of non drinking days and the control group showed a 50% improvement. However, at 6 months, 9 months, and 12 months, the study group continued to maintain these gains while the control group showed a downward slide (differences significant at P < 0.05. At the end of 12 months, the study group maintained a 53% improvement with respect to the number of non drinking days as compared with baseline, while the control group had an improvement of only 28%. Conclusions: Follow-up support and continued care appear to significantly improve longer-term recovery in alcohol dependents.

  13. Ethanol from Whey: Continuous Fermentation with a Catabolite Repression-Resistant Saccharomyces cerevisiae Mutant.

    Science.gov (United States)

    Terrell, S L; Bernard, A; Bailey, R B

    1984-09-01

    An alternative method for the conversion of cheese whey lactose into ethanol has been demonstrated. With the help of continuous-culture technology, a catabolite repression-resistant mutant of Saccharomyces cerevisiae completely fermented equimolar mixtures of glucose and galactose into ethanol. The first step in this process was a computer-controlled fed-batch operation based on the carbon dioxide evolution rate of the culture. In the absence of inhibitory ethanol concentrations, this step allowed us to obtain high biomass concentrations before continuous fermentation. The continuous anaerobic process successfully incorporated a cell-recycle system to optimize the fermentor productivity. Under conditions permitting a low residual sugar concentration (continuous feed at a dilution rate of 0.2 h. Complete fermentation of highly concentrated feed solutions (20%) was also demonstrated, but only with greatly diminished fermentor productivity (5.5 g liter h).

  14. Performance comparison of ethanol and butanol production in a continuous and closed-circulating fermentation system with membrane bioreactor.

    Science.gov (United States)

    Chen, Chunyan; Long, Sihua; Li, Airong; Xiao, Guoqing; Wang, Linyuan; Xiao, Zeyi

    2017-03-16

    Since both ethanol and butanol fermentations are urgently developed processes with the biofuel-demand increasing, performance comparison of aerobic ethanol fermentation and anerobic butanol fermentation in a continuous and closed-circulating fermentation (CCCF) system was necessary to achieve their fermentation characteristics and further optimize the fermentation process. Fermentation and pervaporation parameters including the average cell concentration, glucose consumption rate, cumulated production concentration, product flux, and separation factor of ethanol fermentation were 11.45 g/L, 3.70 g/L/h, 655.83 g/L, 378.5 g/m(2)/h, and 4.83, respectively, the corresponding parameters of butanol fermentation were 2.19 g/L, 0.61 g/L/h, 28.03 g/L, 58.56 g/m(2)/h, and 10.62, respectively. Profiles of fermentation and pervaporation parameters indicated that the intensity and efficiency of ethanol fermentation was higher than butanol fermentation, but the stability of butanol fermentation was superior to ethanol fermentation. Although the two fermentation processes had different features, the performance indicated the application prospect of both ethanol and butanol production by the CCCF system.

  15. Temperature control in a continuously mixed bioreactor for solid-state fermentation

    NARCIS (Netherlands)

    Nagel, F.J.J.I.; Tramper, J.; Bakker, M.S.N.; Rinzema, A.

    2001-01-01

    A continuously mixed, aseptic paddle mixer was used successfully for solid-state fermentation (SSF) with Aspergillus oryzae on whole wheat kernels. Continuous mixing improved temperature control and prevented inhomogeneities in the bed. Respiration rates found in this system were comparable to those

  16. Continuous two stage acetone-butanol-ethanol fermentation with integrated solvent removal using Clostridium acetobutylicum B 5313.

    Science.gov (United States)

    Bankar, Sandip B; Survase, Shrikant A; Singhal, Rekha S; Granström, Tom

    2012-02-01

    The objective of this study was to optimize continuous acetone-butanol-ethanol (ABE) fermentation using a two stage chemostat system integrated with liquid-liquid extraction of solvents produced in the first stage. This minimized end product inhibition by butanol and subsequently enhanced glucose utilization and solvent production in continuous cultures of Clostridium acetobutylicum B 5313. During continuous two-stage ABE fermentation, sugarcane bagasse was used as the cell holding material for the both stages and liquid-liquid extraction was performed using an oleyl alcohol and decanol mixture. An overall solvent production of 25.32g/L (acetone 5.93g/L, butanol 16.90g/L and ethanol 2.48g/L) was observed as compared to 15.98g/L in the single stage chemostat with highest solvent productivity and solvent yield of 2.5g/Lh and of 0.35g/g, respectively. Maximum glucose utilization (83.21%) at a dilution rate of 0.051/h was observed as compared to 54.38% in the single stage chemostat. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Nonlinear analysis and control of a continuous fermentation process

    DEFF Research Database (Denmark)

    Szederkényi, G.; Kristensen, Niels Rode; Hangos, K.M

    2002-01-01

    open-loop system properties, to explore the possible control difficulties and to select the system output to be used in the control structure. A wide range of controllers are tested including pole placement and LQ controllers, feedback and input–output linearization controllers and a nonlinear...... controller based on direct passivation. The comparison is based on time-domain performance and on investigating the stability region, robustness and tuning possibilities of the controllers. Controllers using partial state feedback of the substrate concentration and not directly depending on the reaction rate...... are recommended for the simple fermenter. Passivity based controllers have been found to be globally stable, not very sensitive to the uncertainties in the reaction rate and controller parameter but they require full nonlinear state feedback....

  18. Alcoholic fermentation with flocculant Saccharomyces cerevisiae in fed-batch process.

    Science.gov (United States)

    Guidini, Carla Zanella; Marquez, Líbia Diniz Santos; de Almeida Silva, Helisângela; de Resende, Miriam Maria; Cardoso, Vicelma Luiz; Ribeiro, Eloízio Júlio

    2014-02-01

    Studies have been conducted on selecting yeast strains for use in fermentation for ethanol production to improve the performance of industrial plants and decrease production costs. In this paper, we study alcoholic fermentation in a fed-batch process using a Saccharomyces cerevisiae yeast strain with flocculant characteristics. Central composite design (CCD) was used to determine the optimal combination of the variables involved, with the sucrose concentration of 170 g/L, a cellular concentration in the inoculum of 40% (v/v), and a filling time of 6 h, which resulted in a 92.20% yield relative to the theoretical maximum yield, a productivity of 6.01 g/L h and a residual sucrose concentration of 44.33 g/L. With some changes in the process such as recirculation of medium during the fermentation process and increase in cellular concentration in the inoculum after use of the CCD was possible to reduce the residual sucrose concentration to 2.8 g/L in 9 h of fermentation and increase yield and productivity for 92.75% and 9.26 g/L h, respectively. A model was developed to describe the inhibition of alcoholic fermentation kinetics by the substrate and the product. The maximum specific growth rate was 0.103 h(-1), with K(I) and K(s) values of 109.86 and 30.24 g/L, respectively. The experimental results from the fed-batch reactor show a good fit with the proposed model, resulting in a maximum growth rate of 0.080 h(-1).

  19. Stressful Events and Continued Smoking and Continued Alcohol Consumption during Mid-Pregnancy

    NARCIS (Netherlands)

    Beijers, C.; Ormel, J.; Meijer, J. L.; Verbeek, T.; Bockting, C. L. H.; Burger, H.

    2014-01-01

    Aim: to examine whether the severity of different categories of stressful events is associated with continued smoking and alcohol consumption during mid-pregnancy. Also, we explored the explanation of these associations by anxiety and depressive symptoms during pregnancy. Finally, we studied whether

  20. Stressful events and continued smoking and continued alcohol consumption during mid-pregnancy

    NARCIS (Netherlands)

    Beijers, Chantal; Ormel, Johan; Meijer, Judith L; Verbeek, Tjitte; Bockting, Claudi L H; Burger, Huibert

    2014-01-01

    Aim: to examine whether the severity of different categories of stressful events is associated with continued smoking and alcohol consumption during mid-pregnancy. Also, we explored the explanation of these associations by anxiety and depressive symptoms during pregnancy. Finally, we studied whether

  1. 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 de......, respectively. The overexpression of ADH3 in D. bruxellensis also reduced the inhibition of fermentation by anaerobiosis, the "Custer effect". Thus, the fermentative capacity of D. bruxellensis could be further improved by metabolic engineering....

  2. Pulque, a Traditional Mexican Alcoholic Fermented Beverage: Historical, Microbiological, and Technical Aspects

    Science.gov (United States)

    Escalante, Adelfo; López Soto, David R.; Velázquez Gutiérrez, Judith E.; Giles-Gómez, Martha; Bolívar, Francisco; López-Munguía, Agustín

    2016-01-01

    Pulque is a traditional Mexican alcoholic beverage produced from the fermentation of the fresh sap known as aguamiel (mead) extracted from several species of Agave (maguey) plants that grow in the Central Mexico plateau. Currently, pulque is produced, sold and consumed in popular districts of Mexico City and rural areas. The fermented product is a milky white, viscous, and slightly acidic liquid beverage with an alcohol content between 4 and 7° GL and history of consumption that dates back to pre-Hispanic times. In this contribution, we review the traditional pulque production process, including the microbiota involved in the biochemical changes that take place during aguamiel fermentation. We discuss the historical relevance and the benefits of pulque consumption, its chemical and nutritional properties, including the health benefits associated with diverse lactic acid bacteria with probiotic potential isolated from the beverage. Finally, we describe the actual status of pulque production as well as the social, scientific and technological challenges faced to preserve and improve the production of this ancestral beverage and Mexican cultural heritage. PMID:27446061

  3. Pulque, a Traditional Mexican Alcoholic Fermented Beverage: Historical, Microbiological, and Technical Aspects.

    Science.gov (United States)

    Escalante, Adelfo; López Soto, David R; Velázquez Gutiérrez, Judith E; Giles-Gómez, Martha; Bolívar, Francisco; López-Munguía, Agustín

    2016-01-01

    Pulque is a traditional Mexican alcoholic beverage produced from the fermentation of the fresh sap known as aguamiel (mead) extracted from several species of Agave (maguey) plants that grow in the Central Mexico plateau. Currently, pulque is produced, sold and consumed in popular districts of Mexico City and rural areas. The fermented product is a milky white, viscous, and slightly acidic liquid beverage with an alcohol content between 4 and 7° GL and history of consumption that dates back to pre-Hispanic times. In this contribution, we review the traditional pulque production process, including the microbiota involved in the biochemical changes that take place during aguamiel fermentation. We discuss the historical relevance and the benefits of pulque consumption, its chemical and nutritional properties, including the health benefits associated with diverse lactic acid bacteria with probiotic potential isolated from the beverage. Finally, we describe the actual status of pulque production as well as the social, scientific and technological challenges faced to preserve and improve the production of this ancestral beverage and Mexican cultural heritage.

  4. Continuous lactose fermentation by Clostridium acetobutylicum - Assessment of solventogenic kinetics

    NARCIS (Netherlands)

    Procentese, Alessandra; Raganati, Francesca; Olivieri, Giuseppe; Russo, Maria Elena; Salatino, Piero; Marzocchella, Antonio

    2015-01-01

    This work reports the results of a series of tests on the specific butanol production rate by Clostridium acetobutylicum continuous cultures. The tests were carried out using lactose as carbon source to mimic cheese-whey. A continuous stirred tank reactor equipped with a microfiltration unit was

  5. Continuous lactose fermentation by Clostridium acetobutylicum - Assessment of solventogenic kinetics

    NARCIS (Netherlands)

    Procentese, Alessandra; Raganati, Francesca; Olivieri, Giuseppe; Russo, Maria Elena; Salatino, Piero; Marzocchella, Antonio

    2015-01-01

    This work reports the results of a series of tests on the specific butanol production rate by Clostridium acetobutylicum continuous cultures. The tests were carried out using lactose as carbon source to mimic cheese-whey. A continuous stirred tank reactor equipped with a microfiltration unit was

  6. Accumulation of non-superoxide anion reactive oxygen species mediates nitrogen-limited alcoholic fermentation by Saccharomyces cerevisiae.

    Science.gov (United States)

    Mendes-Ferreira, Ana; Sampaio-Marques, Belém; Barbosa, Catarina; Rodrigues, Fernando; Costa, Vítor; Mendes-Faia, Arlete; Ludovico, Paula; Leão, Cecília

    2010-12-01

    Throughout alcoholic fermentation, nitrogen depletion is one of the most important environmental stresses that can negatively affect the yeast metabolic activity and ultimately leads to fermentation arrest. Thus, the identification of the underlying effects and biomarkers of nitrogen limitation is valuable for controlling, and therefore optimizing, alcoholic fermentation. In this study, reactive oxygen species (ROS), plasma membrane integrity, and cell cycle were evaluated in a wine strain of Saccharomyces cerevisiae during alcoholic fermentation in nitrogen-limiting medium under anaerobic conditions. The results indicated that nitrogen limitation leads to an increase in ROS and that the superoxide anion is a minor component of the ROS, but there is increased activity of both Sod2p and Cta1p. Associated with these effects was a decrease in plasma membrane integrity and a persistent cell cycle arrest at G(0)/G(1) phases. Moreover, under these conditions it appears that autophagy, evaluated by ATG8 expression, is induced, suggesting that this mechanism is essential for cell survival but does not prevent the cell cycle arrest observed in slow fermentation. Conversely, nitrogen refeeding allowed cells to reenter cell cycle by decreasing ROS generation and autophagy. Altogether, the results provide new insights on the understanding of wine fermentations under nitrogen-limiting conditions and further indicate that ROS accumulation, evaluated by the MitoTracker Red dye CM-H(2)XRos, and plasma membrane integrity could be useful as predictive markers of fermentation problems.

  7. 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.

  8. Design of a lamella settler for biomass recycling in continuous ethanol fermentation process.

    Science.gov (United States)

    Tabera, J; Iznaola, M A

    1989-04-20

    The design and application of a settler to a continuous fermentation process with yeast recycle were studied. The compact lamella-type settler was chosen to avoid large volumes associated with conventional settling tanks. A rationale of the design method is covered. The sedimentation area was determined by classical batch settling rate tests and sedimentation capacity calculation. Limitations on the residence time of the microorganisms in the settler, rather than sludge thickening considerations, was the approach employed for volume calculation. Fermentation rate tests with yeast after different sedimentation periods were carried out to define a suitable residence time. Continuous cell recycle fermentation runs, performed with the old and new sedimentation devices, show that lamella settler improves biomass recycling efficiency, being the process able to operate at higher sugar concentrations and faster dilution rates.

  9. Separation of 1,3-propanediol from glycerol-based fermentations of Klebsiella pneumoniae by alcohol precipitation and dilution crystallization

    Institute of Scientific and Technical Information of China (English)

    GAO Sujun; ZHANG Daijia; SUN Yaqin; XIU Zhilong

    2007-01-01

    The separation of 1,3-propanediol from the glycerol-based fermentation broth of Klebsiella pneumoniae plays an important role during the microbial production of 1,3-propanediol.In this paper,the separation of 1,3-propanediol from fermentative broth by a combination of ultrafiltration and alcohol dilution crystallization was investigated.The broth was first filtered by ultrafiltration,and 99%of cells,89.4% of proteins and 69% of nucleic acids were removed.The obtained broth was further condensed by vacuum distillation,and then alcohol was added.The macromolecular impurities,such as nucleic acids,polysaccharides and proteins,were precipitated,and inorganic and organic salts were crystallized.The optimal volume ratio of alcohol added to the condensed fermentation broth was determined to tivity decreased by 97.4%,89.7% and 95.8%,respectively,compared with the fermentative broth.The influences of pH and water content in condensed broth on alcohol precipitation and dilution crystallization were also investigated.The experimental results indicated that alcohol precipitation and dilution crystallization was feasible and effective for the separation of 1,3-propanediol from actual fermentation broth.

  10. Effect of Nitric Oxide on Alcoholic Fermentation and Qualities of Chinese Winter Jujube During Storage

    Institute of Scientific and Technical Information of China (English)

    SUN Li-na; LIU Meng-chen; ZHU Shu-hua; ZHOU Jie; WANG Ming-lin

    2007-01-01

    This article investigates the effects of nitric oxide (NO) on alcoholic fermentation and the qualities of Chinese Winter Jujube during storage, and explores the action mechanisms of browning and softening of fruits to provide theoretical proofs for using NO in the storage of Chinese Winter Jujube. Chinese Winter Jujube fruits were fumigated with different concentrations of NO gas (0, 10, 20, 30 μL L-1) under anaerobic conditions and stored at 22 ± 1 ℃ and 4 ± 1 ℃. The changes in appearance qualities, the contents of pyruvate, ethanol, acetaldehyde, and the activities of alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH) were investigated. The contents of pyruvate, ethanol, and acetaldehyde were significantly reduced, and the peak of pyruvate content was delayed by 20 μL L-1 NO. The activities of ADH and LDH in 20 μL L-1 NO treated fruits were also significantly inhibited. However, the alcoholic fermentation and softening of Chinese Winter Jujube fruits were promoted by 30 μL L-1 NO during storage. The results indicated that 20 μL L-1 NO could mitigate the injury of ethanol on Chinese Winter Jujube and effectively delay the browning and softening of fruits during storage.

  11. Alternative non-chromatographic method for alcohols determination in Clostridium acetobutylicum fermentations.

    Science.gov (United States)

    Noriega-Medrano, Laura J; Vega-Estrada, Jesús; Ortega-López, Jaime; Ruiz-Medrano, Roberto; Cristiani-Urbina, Eliseo; Montes-Horcasitas, Maria Del Carmen

    2016-07-01

    An economic, simple, quantitative, and non-chromatographic method for the determination of alcohols using microdiffusion principle has been adapted and validated for acetone-butanol-ethanol (ABE) fermentation samples. This method, based on alcohols oxidation using potassium dichromate in acid medium, and detection by spectrophotometry, was evaluated varying, both, temperature (35°C, 45°C, and 55°C) and reaction time (0 to 125min). With a sample analysis time of 90min at 45°C, a limit of detection (LOD), and a limit of quantification (LOQ) of 0.10, and 0.40g/L, respectively. The proposed method has been successfully applied to determine butanol and ethanol concentrations in ABE fermentation samples with the advantage that multiple samples can be analyzed simultaneously. The measurements obtained with the proposed method were in good agreement with those obtained with the Gas Chromatography Method (GCM). This proposed method is useful for routine analysis of alcohols and screening samples in laboratories and industries. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Genomic diversity of Saccharomyces cerevisiae yeasts associated with alcoholic fermentation of bacanora produced by artisanal methods.

    Science.gov (United States)

    Álvarez-Ainza, M L; Zamora-Quiñonez, K A; Moreno-Ibarra, G M; Acedo-Félix, E

    2015-03-01

    Bacanora is a spirituous beverage elaborated with Agave angustifolia Haw in an artisanal process. Natural fermentation is mostly performed with native yeasts and bacteria. In this study, 228 strains of yeast like Saccharomyces were isolated from the natural alcoholic fermentation on the production of bacanora. Restriction analysis of the amplified region ITS1-5.8S-ITS2 of the ribosomal DNA genes (RFLPr) were used to confirm the genus, and 182 strains were identified as Saccharomyces cerevisiae. These strains displayed high genomic variability in their chromosomes profiles by karyotyping. Electrophoretic profiles of the strains evaluated showed a large number of chromosomes the size of which ranged between 225 and 2200 kpb approximately.

  13. GAL promoter-driven heterologous gene expression in Saccharomyces cerevisiae Δ strain at anaerobic alcoholic fermentation.

    Science.gov (United States)

    Ahn, Jungoh; Park, Kyung-Min; Lee, Hongweon; Son, Yeo-Jin; Choi, Eui-Sung

    2013-02-01

    The removal of Gal80 protein by gene disruption turned into efficient GAL promoter-driven heterologous gene expression under anaerobic alcoholic fermentation of Saccharomyces cerevisiae. Using lipase B from Candida antarctica as a reporter, the relative strength of GAL10 promoter (P(GAL10) ) in Δgal80 mutant that does not require galactose as an inducer was compared to those of ADH1, PDC1, and PGK promoters, which have been known to work well anaerobically in actively fermenting yeast cells under high glucose concentration. P(GAL10) in the Δgal80 mutant showed 0.8-fold (ADH1), fourfold (PDC1), and 50-fold (PGK) in promoter strength.

  14. A plant kinetic study of alcoholic fermentation using reversed-flow gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Economopoulos, N.; Athanassopoulos, N. (B.G. Spiliopoulos Distilleri S.A., Patras (Greece)); Katsanos, N.A.; Karaiskakis, G.; Agathonos, P.; Vassilakos, Ch. (Univ. of Patras (Greece))

    1992-12-01

    The reversed-flow gas chromatographic sampling technique is used to study the kinetics of alcoholic fermentation in a factory in conjunction with measurements of suspended particles in the fermenting medium. It was found that the overall process consists of four phases which have different first-order rate constants during ethanol formation. The second phase is the slowest with its rate constant being 4.3 and 13 times smaller than that of the first and third phases, respectively. There is also a decrease of suspended particles during the second phase. These results show that there is the possibility of increasing the rate constant during this phase, thereby increasing the overall production rate of ethanol significantly and thus lowering its cost of production.

  15. High alcohol production by solid substrate fermentation from starchy substrates using thermotolerant Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Sree, N.K.; Sridhar, M.; Suresh, K.; Rao, L.V. [Department of Microbiology, Osmania University, Hyderabad 500007, Andhra Pradesh (India)

    1999-06-01

    Solid Substrate Fermentation system (SSF) was used to produce ethanol from various starchy substrates like sweet sorghum, sweet potato, wheat flour, rice starch, soluble starch and potato starch using thermotolerant yeast isolate (VS{sub 3}) by simultaneous saccharification and fermentation process. Alcohol produced was estimated by gas chromatography after an incubation time of 96 hrs at 37 C and 42 C. More ethanol was produced from rice starch and sweet sorghum. The maximum amount of ethanol produced from these substrates using VS{sub 3} was 10 g/100 g and 3.5 g/100 g substrate (rice starch) and 8.2 g and 7.5 g/100 g substrate (sweet sorghum) at 37 C and 42 C respectively. (orig.) With 2 figs., 1 tab., 12 refs.

  16. Direct in situ butanol recovery inside the packed bed during continuous acetone-butanol-ethanol (ABE) fermentation.

    Science.gov (United States)

    Wang, Yin-Rong; Chiang, Yu-Sheng; Chuang, Po-Jen; Chao, Yun-Peng; Li, Si-Yu

    2016-09-01

    In this study, the integrated in situ extraction-gas stripping process was coupled with continuous ABE fermentation using immobilized Clostridium acetobutylicum. At the same time, oleyl alcohol was cocurrently flowed into the packed bed reactor with the fresh medium and then recycled back to the packed bed reactor after removing butanol in the stripper. A high glucose consumption of 52 g/L and a high butanol productivity of 11 g/L/h were achieved, resulting in a high butanol yield of 0.21 g-butanol/g-glucose. This can be attributed to both the high bacterial activity for solvent production as well as a threefold increase in the bacterial density inside the packed bed reactor. Also reported is that 64 % of the butanol produced can be recovered by the integrated in situ extraction-gas stripping process. A high butanol productivity and a high glucose consumption were simultaneously achieved.

  17. Transcriptional activator Cat8 is involved in regulation of xylose alcoholic fermentation in the thermotolerant yeast Ogataea (Hansenula) polymorpha.

    Science.gov (United States)

    Ruchala, Justyna; Kurylenko, Olena O; Soontorngun, Nitnipa; Dmytruk, Kostyantyn V; Sibirny, Andriy A

    2017-02-28

    Efficient xylose alcoholic fermentation is one of the key to a successful lignocellulosic ethanol production. However, regulation of this process in the native xylose-fermenting yeasts is poorly understood. In this work, we paid attention to the transcriptional factor Cat8 and its possible role in xylose alcoholic fermentation in Ogataea (Hansenula) polymorpha. In Saccharomyces cerevisiae, organism, which does not metabolize xylose, gene CAT8 encodes a Zn-cluster transcriptional activator necessary for expression of genes involved in gluconeogenesis, respiration, glyoxylic cycle and ethanol utilization. Xylose is a carbon source that could be fermented to ethanol and simultaneously could be used in gluconeogenesis for hexose synthesis. This potentially suggests involvement of CAT8 in xylose metabolism. Here, the role of CAT8 homolog in the natural xylose-fermenting thermotolerant yeast O. polymorpha was characterized. The CAT8 ortholog was identified in O. polymorpha genome and deleted both in the wild-type strain and in advanced ethanol producer from xylose. Constructed cat8Δ strain isolated from wild strain showed diminished growth on glycerol, ethanol and xylose as well as diminished respiration on the last substrate. At the same time, cat8Δ mutant isolated from the best available O. polymorpha ethanol producer showed only visible defect in growth on ethanol. CAT8 deletant was characterized by activated transcription of genes XYL3, DAS1 and RPE1 and slight increase in the activity of several enzymes involved in xylose metabolism and alcoholic fermentation. Ethanol production from xylose in cat8Δ mutants in the background of wild-type strain and the best available ethanol producer from xylose increased for 50 and 30%, respectively. The maximal titer of ethanol during xylose fermentation was 12.5 g ethanol/L at 45 °C. Deletion of CAT8 did not change ethanol production from glucose. Gene CAT8 was also overexpressed under control of the strong constitutive

  18. Enteric methane production and ruminal fermentation from forage brassica diets fed in continuous culture

    Science.gov (United States)

    Brassicas provide forage for livestock during the late fall when traditional perennial cool-season forages are not productive. However, little research exists on ruminal fermentation and methane(CH4) production of brassicas fed as forage. A continuous culture fermentor system was used to assess nutr...

  19. The influence of molasses addition on the kinetics of alcoholic fermentation of whey using Kluyveromyces marxianus yeast

    Directory of Open Access Journals (Sweden)

    Damir Stanzer

    2004-01-01

    Full Text Available Kinetics of alcoholic fermentation by yeast Kluyveromyces marxianusZIM 75 in various media based on whey and molasses were monitored. The fermentations were performed under static and semiaerobic conditions at 34°C. Deproteinized whey and molasses were mixed in various proportions to give final sugar mass concentrations of 5%, 10% and 15% in medium. The experiments conducted showed that medium with 10 % of sugar (sucrose:lactose=1:1 is optimal for alcoholic fermentations in static and semiaerobic conditions. The best ethanol yield after 24 hours of fermentation was 4.05 % (V/V in static conditions and 4.9 % (V/V in semiaerobic conditions. The biomass yield was 7.78 g d.m./L in semiaerobic conditions and 3.19 g d.m./L in static conditions.

  20. Isolation, identification and optimization of ethanol producing bacteria from Saccharomyces-based fermentation process of alcohol industries in Iran

    OpenAIRE

    Hoda Ebrahimi; Mojtaba Mohseni

    2013-01-01

    Introduction: Due to the vast growth of world population, consumption of a lot of energy, limited energy supply and rising prices of fuel oil in the future, other alternative energy source is essential. Ethanol is renewable and a safe fuel and it is mainly based on microbial fermentation. The purpose of this study was isolation of high ethanol producing bacteria from the fermentation process of alcohol industries and optimization of growth conditions to be introduced to the industries. Materi...

  1. Study and management of atmospheric exhaust gas in acetic acid fermentation developing a new process for alcohol vinegar production; Etude et maitrise des rejets atmospheriques en vinaigrerie, developpement d'un procede nouveau de conduite de la fermentation acetique

    Energy Technology Data Exchange (ETDEWEB)

    Pochat Bohatier, C.

    1999-12-06

    The aim of the study was to examine emissions of volatile organic compounds (VOCs) during acetic (acid) fermentation. The first part of the study presents the methodology developed to reproduce production cycles for spirit vinegar and to analyse gas effluents. The second part describes the origin and quantification of the emissions (ethanol, acetic acid, acetaldehyde and ethyl acetate). The acetic acid is produced by bacterial metabolism while the ethyl acetate is a result of the chemical reaction of esterification. By modelling the emissions during batch processing we were able to identify the various parameters involved when VOCs are carried along by the fermentation gases. The quantities of ethyl acetate depend on the length of time the diluted alcohol is stored, and on its composition. By using a fed-batch method with a continuous supply of ethanol we could reduce alcohol emissions. The third part of the study develops the kinetics studies carried out to adapt the fed-batch process to acetic acid fermentation. The influence of ethanol, either in terms of deficiency or inhibition, is minimized between 8 and 16 g.1-1. A study of the growth rate of bacteria in relation to the amount of acetic acid showed that the latter was highly inhibitive. There is a critical concentration of acetic acid at which the growth of bacteria stops, and the death rate of the culture increases rapidly. The latter depends on the composition of the culture's medium; the corresponding pH of the concentration is between 2.25 and 2.28. By limiting the formation of ethyl acetate in the diluted alcohol and by controlling the concentration of ethanol at 16 g.l -1 per fermentation, the VOC emissions are reduced by 30% and the yield increases as a result. (author)

  2. An Experimental Trial Exploring the Impact of Continuous Transdermal Alcohol Monitoring upon Alcohol Consumption in a Cohort of Male Students

    OpenAIRE

    2013-01-01

    Objective: To examine the impact of continuous transdermal alcohol monitoring upon alcohol consumption in male students at a Scottish university.\\ud \\ud Method: Using a within-subject mixed-methods design, 60 male university students were randomly allocated into three experimental conditions using AUDIT score stratified sampling. Participants in Conditions A and B were asked not to consume alcohol for a 14-day period, with those in Condition A additionally being required to wear a continuous ...

  3. An experimental trial exploring the impact of continuous transdermal alcohol monitoring upon alcohol consumption in a cohort of male students.

    Directory of Open Access Journals (Sweden)

    Fergus G Neville

    Full Text Available OBJECTIVE: To examine the impact of continuous transdermal alcohol monitoring upon alcohol consumption in male students at a Scottish university. METHOD: Using a within-subject mixed-methods design, 60 male university students were randomly allocated into three experimental conditions using AUDIT score stratified sampling. Participants in Conditions A and B were asked not to consume alcohol for a 14-day period, with those in Condition A additionally being required to wear a continuous transdermal alcohol monitoring anklet. Condition C participants wore an anklet and were asked to continue consuming alcohol as normal. Alcohol consumption was measured through alcohol timeline follow-back, and using data collected from the anklets where available. Diaries and focus groups explored participants' experiences of the trial. RESULTS: Alcohol consumption during the 14-day trial decreased significantly for participants in Conditions A and B, but not in C. There was no significant relative difference in units of alcohol consumed between Conditions A and B, but significantly fewer participants in Condition A drank alcohol than in Condition B. Possible reasons for this difference identified from the focus groups and diaries included the anklet acting as a reminder of commitment to the study (and the agreement to sobriety, participants feeling under surveillance, and the use of the anklet as a tool to resist social pressure to consume alcohol. CONCLUSIONS: The study provided experience in using continuous transdermal alcohol monitors in an experimental context, and demonstrated ways in which the technology may be supportive in facilitating sobriety. Results from the study have been used to design a research project using continuous transdermal alcohol monitors with ex-offenders who recognise a link between their alcohol consumption and offending behaviour.

  4. An experimental trial exploring the impact of continuous transdermal alcohol monitoring upon alcohol consumption in a cohort of male students.

    Science.gov (United States)

    Neville, Fergus G; Williams, Damien J; Goodall, Christine A; Murer, Jeffrey S; Donnelly, Peter D

    2013-01-01

    To examine the impact of continuous transdermal alcohol monitoring upon alcohol consumption in male students at a Scottish university. Using a within-subject mixed-methods design, 60 male university students were randomly allocated into three experimental conditions using AUDIT score stratified sampling. Participants in Conditions A and B were asked not to consume alcohol for a 14-day period, with those in Condition A additionally being required to wear a continuous transdermal alcohol monitoring anklet. Condition C participants wore an anklet and were asked to continue consuming alcohol as normal. Alcohol consumption was measured through alcohol timeline follow-back, and using data collected from the anklets where available. Diaries and focus groups explored participants' experiences of the trial. Alcohol consumption during the 14-day trial decreased significantly for participants in Conditions A and B, but not in C. There was no significant relative difference in units of alcohol consumed between Conditions A and B, but significantly fewer participants in Condition A drank alcohol than in Condition B. Possible reasons for this difference identified from the focus groups and diaries included the anklet acting as a reminder of commitment to the study (and the agreement to sobriety), participants feeling under surveillance, and the use of the anklet as a tool to resist social pressure to consume alcohol. The study provided experience in using continuous transdermal alcohol monitors in an experimental context, and demonstrated ways in which the technology may be supportive in facilitating sobriety. Results from the study have been used to design a research project using continuous transdermal alcohol monitors with ex-offenders who recognise a link between their alcohol consumption and offending behaviour.

  5. Alcoholic fermentation of glucose and xylose by Pichia stipitis, Candida shehatae, Saccharomyces cerevisiae and Zymomonas mobilis: Oxygen requirement as a key factor

    Energy Technology Data Exchange (ETDEWEB)

    Laplace, J.M.; Delgenes, J.P.; Moletta, R. (Institut National de la Recherche Agronomique, 11 - Narbonne (France). Lab. de Biotechnologie de l' Environnement); Navarro, J.M. (Montpellier-2 Univ., 34 (France). Genie Biologique et Sciences des Aliments)

    1991-11-01

    To investigate simultaneous alcoholic fermentation of glucose and xylose derived from lignocellulosic material by separate or co-culture processes, the effect of oxygen transfer rate (OTR) on the fermentation of 50 g/l xylose by Pichia stipitis NRRL Y 7124 and Candida shehatae ATCC 22984, and the fermentation of 50 g/l glucose by Saccharomyces cerevisiae CBS 1200 and Zymomonas mobilis ATCC 10988 was carried out in batch cultures. The kinetic parameters of the xylose-fermenting yeasts were greatly dependent on the OTR. The optimum OTR values were found to be 3.9 and 1.75 mmol.l{sup -1}.h{sup -1} for C. shehatae and P. stipitis, respectively. By contrast the fermentative parameters of S. cerevisiae were poorly affected by the OTR range tested (0.0-3.5 mmol.l{sup -1}.h{sup -1}). Under these conditions the ethanol yields ranged from 0.41 g.g{sup -1} to 0.45 g.g{sup -1} and the specific ethanol productivity was around 0.70 g.g{sup -1}.h{sup -1}. Z. mobilis gave the highest fermentative performance under strictly anaerobic conditions (medium continually flushed with nitrogen): Under these conditions, the ethanol yield was 0.43 g.g{sup -1} and the average specific ethanol productivity was 2.3 g.g{sup -1}.h{sup -1}. Process considerations in relation to the effect of OTR on the fermentative performance of the tested strains are discussed. (orig.).

  6. Production of teicoplanin by Actinoplanes teichomyceticus in continuous fermentation

    DEFF Research Database (Denmark)

    Vara, A.G.; Hochkoepple, A.; Nielsen, Jens

    2002-01-01

    Production of the potent antibiotic teicoplanin by Actinoplanes teichomyceticus was studied in batch and in chemostat cultures. It is found that the producing strain deactivates to a non-producing strain named NP-12. This strain is used to find the growth kinetics of the A. teichomyceticus without...... interference from the product teicoplanin. In batch experiments with NP-12 grown on glucose at different initial concentrations and with different added amounts of teicoplanin, the strong inhibitory effect of teicoplanin was determined. These results obtained on NP-12 were validated in a series of chemostat....... For industrial production of teicoplanin, a continuous reactor with cell recirculation and working with a low effluent glucose concentration was by far the best mode of operation. Finally, the deactivation of the producing strain to NP-12 was modeled by a two-step deactivation mechanism. Deactivation...

  7. Analysis of mixtures of fatty acids and fatty alcohols in fermentation broth.

    Science.gov (United States)

    Liu, Yilan; Chen, Ting; Yang, Maohua; Wang, Caixia; Huo, Weiyan; Yan, Daojiang; Chen, Jinjin; Zhou, Jiemin; Xing, Jianmin

    2014-01-03

    Microbial production of fatty acids and fatty alcohols has attracted increasing concerns because of energy crisis and environmental impact of fossil fuels. Therefore, simple and efficient methods for the extraction and quantification of these compounds become necessary. In this study, a high-performance liquid chromatography-refractive index detection (HPLC-RID) method was developed for the simultaneous quantification of fatty acids and fatty alcohols in these samples. The optimum chromatographic conditions are C18 column eluted with methanol:water:acetic acid (90:9.9:0.1, v/v/v); column temperature, 26°C; flow rate, 1.0mL/min. Calibration curves of all selected analytes showed good linearity (r(2)≥0.9989). The intra-day and inter-day relative standard deviations (RSDs) of the 10 compounds were less than 4.46% and 5.38%, respectively, which indicated that the method had good repeatability and precision. Besides, a method for simultaneous extraction of fatty acids and fatty alcohols from fermentation broth was optimized by orthogonal design. The optimal extraction conditions were as follows: solvent, ethyl acetate; solvent to sample ratio, 0.5:1; rotation speed, 2min at 260rpm; extraction temperature, 10°C. This study provides simple and fast methods to simultaneously extract and quantify fatty acids and fatty alcohols for the first time. It will be useful for the study of microbial production of these products. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Effect of alcoholic fermentation on the carotenoid composition and provitamin A content of orange juice.

    Science.gov (United States)

    Cerrillo, Isabel; Escudero-López, Blanca; Hornero-Méndez, Dámaso; Martín, Francisco; Fernández-Pachón, María-Soledad

    2014-01-29

    Orange juice is considered a rich source of carotenoids, which are thought to have diverse biological functions. In recent years, a fermentation process has been carried out in fruits resulting in products that provide higher concentrations of bioactive compounds than their original substrates. The aim of this study was to evaluate the effect of a controlled alcoholic fermentation process (15 days) on the carotenoid composition of orange juice. Twenty-two carotenoids were identified in samples. The carotenoid profile was not modified as result of the fermentation. Total carotenoid content and provitamin A value significantly increased from day 0 (5.37 mg/L and 75.32 RAEs/L, respectively) until day 15 (6.65 mg/L and 90.57 RAEs/L, respectively), probably due to a better extractability of the carotenoids from the food matrix as a result of processing. Therefore, the novel beverage produced could provide a rich source of carotenoids and exert healthy effects similar to those of orange juice.

  9. Influence of calcium ion on ethanol tolerance of Saccharomyces bayanus and alcoholic fermentation by yeasts

    Energy Technology Data Exchange (ETDEWEB)

    Nabais, R.C.; Sa-Correia, I.; Viegas, C.A.; Novais, J.M. (Instituto Superior Tecnico, Lisbon (Portugal))

    1988-10-01

    The addition of Ca{sup 2+} (as CaCl{sub 2}) in optimal concentrations (0.75 to 2.0 mM) to a fermentation medium with a trace contaminating concentration of Ca{sup 2+} (0.025 mM) led to the rapid production of higher concentrations of ethanol by Saccharomyces cerevisiae, Saccharomyces bayanus, and Kluyveromyces marxianus. The positive effect of calcium supplementation (0.75 mM) on alcoholic fermentation by S. bayanus was explained by the increase in its ethanol tolerance. For lethal concentrations of ethanol, the specific death rates were minimal for cells that were grown and incubated with ethanol in medium with an optimal concentration of Ca{sup 2+}, maximal for cells grown and incubated with ethanol in unsupplemented medium, and intermediate for cells grown in unsupplemented medium and incubated with ethanol in calcium-supplemented medium. The effect of Ca{sup 2+} on the acidification curve of energized cells in the presence of ethanol was found to be closely associated with its protective effect on growth, fermentation, and viability.

  10. Variation of fermentation redox potential during cell-recycling continuous ethanol operation.

    Science.gov (United States)

    Thani, Arthit; Lin, Yen-Han; Laopaiboon, Pattana; Laopaiboon, Lakkana

    2016-12-10

    Fermentation redox potential was monitored during cell-recycling continuous ethanol operation. The cell-recycling system (CRS) was operated using two hollow fibre (HF) membranes (pore sizes 0.20 and 0.65μm) at three dilution rates (0.02, 0.04 and 0.08h(-1)). Saccharomyces cerevisiae NP 01 were recycled in the fermenter at a recycle ratio of 0.625. Aeration was provided at 2.5vvm for the first 4h and then further supplied continuously at 0.25vvm. As steady state was established, results showed that the fermentation redox potential was lower for processes employing CRS than those without. At the same dilution rates, the sugar utilization and ethanol production with CRS were higher than those without CRS. The highest fermentation efficiency (87.94g/l of ethanol, ∼90% of theoretical yield) was achieved using a 0.2-μm HF membrane CRS at a dilution rate of 0.02h(-1). It was found that 7.53-10.07% of the carbon derived from glucose was incorporated into the yeast. Further, at the same dilution rates, yeast in the processes with CRS incorporated less carbon into ethanol than in those grown without CRS. This result suggests that processes involving CRS utilize more carbon for metabolite synthesis than biomass formation. This indicated that the processes with CRS could utilize more carbon for metabolite synthesis than biomass formation.

  11. Oenological prefermentation practices strongly impact yeast population dynamics and alcoholic fermentation kinetics in Chardonnay grape must.

    Science.gov (United States)

    Albertin, Warren; Miot-Sertier, Cécile; Bely, Marina; Marullo, Philippe; Coulon, Joana; Moine, Virginie; Colonna-Ceccaldi, Benoit; Masneuf-Pomarede, Isabelle

    2014-05-16

    Yeast species of Hanseniaspora and Candida genus are predominant during the early stages of winemaking, while species of Metschnikowia, Pichia, Zygoascus, Issatchenkia, Torulaspora and other genera are present at lower population levels. The impact of common oenological practices on yeast dynamics during the prefermentative stage and the early stage of alcoholic fermentation (AF) remains elusive. In this work, the effect of four prefermentative oenological practices (clarification degree, temperature, sulphite and starter yeast addition) on yeast dynamics was evaluated in a Chardonnay grape must. The growth curves of four genus or species, namely Saccharomyces spp., Hanseniaspora spp., Candida zemplinina and Torulaspora delbrueckii, were followed by quantitative PCR. The fermentation kinetics were also recorded, as well as the production of acetic acid. Variance analysis allowed determining the effect of each practice and their interaction factors, as well as their relative importance on yeast dynamics and fermentation kinetics. Our experimental design showed that the population dynamics of the four species were differently impacted by the oenological practices, with some species being more sensitive than others to the clarification degree (C. zemplinina), sulphite addition (Saccharomyces spp.), starter yeast inoculation (Hanseniaspora spp.) or prefermentation temperature (T. delbrueckii). Significant interaction effects between practices were revealed, highlighting the interest of experimental design allowing interaction analysis, as some factors may buffer the effect of other ones. Hanseniaspora genus showed atypical behaviour: growth dynamics showed a decrease during AF that we interpreted as early cellular lysis. In conclusion, this study provides new insights on the impact of common oenological practices on the dynamics of non-Saccharomyces yeast that will be useful for a better management of mixed fermentation between S. cerevisiae and non

  12. Population size drives industrial Saccharomyces cerevisiae alcoholic fermentation and is under genetic control.

    Science.gov (United States)

    Albertin, Warren; Marullo, Philippe; Aigle, Michel; Dillmann, Christine; de Vienne, Dominique; Bely, Marina; Sicard, Delphine

    2011-04-01

    Alcoholic fermentation (AF) conducted by Saccharomyces cerevisiae has been exploited for millennia in three important human food processes: beer and wine production and bread leavening. Most of the efforts to understand and improve AF have been made separately for each process, with strains that are supposedly well adapted. In this work, we propose a first comparison of yeast AFs in three synthetic media mimicking the dough/wort/grape must found in baking, brewing, and wine making. The fermentative behaviors of nine food-processing strains were evaluated in these media, at the cellular, populational, and biotechnological levels. A large variation in the measured traits was observed, with medium effects usually being greater than the strain effects. The results suggest that human selection targeted the ability to complete fermentation for wine strains and trehalose content for beer strains. Apart from these features, the food origin of the strains did not significantly affect AF, suggesting that an improvement program for a specific food processing industry could exploit the variability of strains used in other industries. Glucose utilization was analyzed, revealing plastic but also genetic variation in fermentation products and indicating that artificial selection could be used to modify the production of glycerol, acetate, etc. The major result was that the overall maximum CO(2) production rate (V(max)) was not related to the maximum CO(2) production rate per cell. Instead, a highly significant correlation between V(max) and the maximum population size was observed in all three media, indicating that human selection targeted the efficiency of cellular reproduction rather than metabolic efficiency. This result opens the way to new strategies for yeast improvement.

  13. The Interaction between Saccharomyces cerevisiae and Non-Saccharomyces Yeast during Alcoholic Fermentation Is Species and Strain Specific.

    Science.gov (United States)

    Wang, Chunxiao; Mas, Albert; Esteve-Zarzoso, Braulio

    2016-01-01

    The present study analyzes the lack of culturability of different non-Saccharomyces strains due to interaction with Saccharomyces cerevisiae during alcoholic fermentation. Interaction was followed in mixed fermentations with 1:1 inoculation of S. cerevisiae and ten non-Saccharomyces strains. Starmerella bacillaris, and Torulaspora delbrueckii indicated longer coexistence in mixed fermentations compared with Hanseniaspora uvarum and Metschnikowia pulcherrima. Strain differences in culturability and nutrient consumption (glucose, alanine, ammonium, arginine, or glutamine) were found within each species in mixed fermentation with S. cerevisiae. The interaction was further analyzed using cell-free supernatant from S. cerevisiae and synthetic media mimicking both single fermentations with S. cerevisiae and using mixed fermentations with the corresponding non-Saccharomyces species. Cell-free S. cerevisiae supernatants induced faster culturability loss than synthetic media corresponding to the same fermentation stage. This demonstrated that some metabolites produced by S. cerevisiae played the main role in the decreased culturability of the other non-Saccharomyces yeasts. However, changes in the concentrations of main metabolites had also an effect. Culturability differences were observed among species and strains in culture assays and thus showed distinct tolerance to S. cerevisiae metabolites and fermentation environment. Viability kit and recovery analyses on non-culturable cells verified the existence of viable but not-culturable status. These findings are discussed in the context of interaction between non-Saccharomyces and S. cerevisiae.

  14. The Interaction between Saccharomyces cerevisiae and Non-Saccharomyces Yeast during Alcoholic Fermentation is Species and Strain Specific

    Directory of Open Access Journals (Sweden)

    Chunxiao eWang

    2016-04-01

    Full Text Available The present study analyzes the lack of culturability of different non-Saccharomyces strains due to interaction with Saccharomyces cerevisiae during alcoholic fermentation. Interaction was followed in mixed fermentations with 1:1 inoculation of S. cerevisiae and ten non-Saccharomyces strains. Starmerella bacillaris and Torulaspora delbrueckii indicated longer coexistence in mixed fermentations compared with Hanseniaspora uvarum and Metschnikowia pulcherrima. Strain differences in culturability and nutrient consumption (glucose, alanine, ammonium, arginine or glutamine were found within each species in mixed fermentation with S. cerevisiae. The interaction was further analyzed using cell-free supernatant from S. cerevisiae and synthetic media mimicking both single fermentations with S. cerevisiae and using mixed fermentations with the corresponding non-Saccharomyces species. Cell-free S. cerevisiae supernatants induced faster culturability loss than synthetic media corresponding to the same fermentation stage. This demonstrated that some metabolites produced by S. cerevisiae played the main role in the decreased culturability of the other non-Saccharomyces yeasts. However, changes in the concentrations of main metabolites had also an effect. Culturability differences were observed among species and strains in culture assays and thus showed distinct tolerance to S. cerevisiae metabolites and fermentation environment. Viability kit and recovery analyses on non-culturable cells verified the existence of viable but not-culturable status. These findings are discussed in the context of interaction between non-Saccharomyces and S. cerevisiae.

  15. Formation of ethanol and higher alcohols by immobilized zymomonas mobilis in continuous culture

    Energy Technology Data Exchange (ETDEWEB)

    Oaxaca, V.A.; Jones, L.P. (Texas Univ., El Paso (United States). Dept. of Biological Sciences)

    1991-01-01

    Cells of Zymomonas mobilis ATCC 10988 were immobilized in 1.5% calcium alginate and packed in a column bioreactor for a series of fermentations utilizing 10.0% glucose media with the addition of one of the following amino acids or keto acids: L-leucine, L-isoleucine, L-valine, {alpha}-ketoisocaproic acid, {alpha}-ketobutyric acid, or {alpha}-ketoisovaleric acid. This was done in order to study the rates of production of higher alcohols during ethanolic fermentations at varying dilution rates while under the influence of amino acids or keto acids. Results indicate that the EHRLICH mechanism is operative in Zymomonas sp. {alpha}-Ketobutyrate enhanced the production of n-propanol and act-amyl alcohol. {alpha}-Ketoisocaproic acid stimulated the production of isoamyl alcohol. {alpha}-Ketoisovaleric acid increased the levels of isobutanol. The amino acids also gave rise to their corresponding alcohols but to a far lesser degree than did the keto acids. During high glucose utilization, ethanol yields ranged from 87% to 94% of theoretical with productivity ranging from 60.08 g/l/h in one fermentation (at a dilution rate of 1.35 h{sup -1}) to 70.42 g/l/h in another (at a dilution rate of 1.58 h{sup -1}). At dilution rates of 1.58 h{sup -1}, higher alcohol productivity rose to as high as 4.313 mg/l/h in the presence of {alpha}-ketoisocaproic acid, 1,734.49 mg/l/h using {alpha}-ketoisovaleric acid, and 1,618.05 mg/l/h in {alpha}-ketobutyric acid. The concomitant production of ethanol and higher alcohols in all of the fermentations indicates that glucose is required for the production of the higher alcohols from their corresponding amino acids or keto acids. (orig.).

  16. Immobilization of Microbial Cells for Alcoholic and Malolactic Fermentation of Wine and Cider

    Science.gov (United States)

    Kourkoutas, Yiannis; Manojlović, Verica; Nedović, Viktor A.

    Wine- or cider-making is highly associated with biotechnology owing to the traditional nature of must fermentation.. Nowadays, there have been considerable developments in wine- or cider-making techniques affecting all phases of wine or cider production, but more importantly, the fermentation process. It is well-known that the transformation of grape must by microbial activity results in the production of wine, and the fermentation of apples (or sometimes pears) in the production of cider. In this process, a variety of compounds affecting the organoleptic profile of wine or cider are synthesized. It is also common sense that in wine- or cider-making, the main objective is to achieve an adequate quality of the product. The technological progress and the improved quality of the wines or ciders have been associated with the control of technical parameters. Herein, cell immobilization offers numerous advantages, such as enhanced fermentation productivity, ability for cell recycling, application of continuous configurations, enhanced cell stability and viability, and improvement of quality (Margaritis and Merchant 1984; Stewart and Russel 1986; Kourkoutas et al. 2004a).

  17. Alcohol fermentation from sago starch granules using raw sago starch digesting amylase from Penicillum brunneum No. 24 and Saccharomyces cerevisaiae No. 33

    Energy Technology Data Exchange (ETDEWEB)

    Haska, Nadirman (Hiroshima Univ., Kagamiyama (Japan). Lab. of Microbial Biochemistry); Ohta, Yoshiyuki (Hiroshima Univ., Kagamiyama (Japan). Lab. of Microbial Biochemistry)

    1993-07-01

    Treatment of the sago starch granules before incubation with the enzyme by heating to below gelatinization temperature at low pH condition was effective in improving the hydrolysis. Glucose could be produced from treated (at 60 C, pH 2.0) sago starch granules using the raw sago starch digesting amylase from our strain. Alcohol fermentation from the treated sago starch granules using the raw sago starch digesting amylase from Penicillium brunneum and a strain of yeast, Saccharomyces cerevisiae No. 33 could produce ethanol under incubation conditions of 35 C, pH 4.8. Addition of yeast and an extra half dose of enzyme after 24 h enzyme reaction was sufficient to continue starch hydrolysis during fermentation. This condition resulted in a conversion of sago starch to ethanol at a rate of about 44% in 72 h culture time. (orig.)

  18. Introducing a single secondary alcohol dehydrogenase into butanol-tolerant Clostridium acetobutylicum Rh8 switches ABE fermentation to high level IBE fermentation

    Directory of Open Access Journals (Sweden)

    Dai Zongjie

    2012-06-01

    Full Text Available Abstract Background Previously we have developed a butanol tolerant mutant of Clostridium acetobutylicum Rh8, from the wild type strain DSM 1731. Strain Rh8 can tolerate up to 19 g/L butanol, with solvent titer improved accordingly, thus exhibiting industrial application potential. To test if strain Rh8 can be used for production of high level mixed alcohols, a single secondary alcohol dehydrogenase from Clostridium beijerinckii NRRL B593 was overexpressed in strain Rh8 under the control of thl promoter. Results The heterogenous gene sADH was functionally expressed in C. acetobutylicum Rh8. This simple, one-step engineering approach switched the traditional ABE (acetone-butanol-ethanol fermentation to IBE (isopropanol-butanol-ethanol fermentation. The total alcohol titer reached 23.88 g/l (7.6 g/l isopropanol, 15 g/l butanol, and 1.28 g/l ethanol with a yield to glucose of 31.42%. The acid (butyrate and acetate assimilation rate in isopropanol producing strain Rh8(psADH was increased. Conclusions The improved butanol tolerance and the enhanced solvent biosynthesis machinery in strain Rh8 is beneficial for production of high concentration of mixed alcohols. Strain Rh8 can thus be considered as a good host for further engineering of solvent/alcohol production.

  19. Introducing a single secondary alcohol dehydrogenase into butanol-tolerant Clostridium acetobutylicum Rh8 switches ABE fermentation to high level IBE fermentation

    Science.gov (United States)

    2012-01-01

    Background Previously we have developed a butanol tolerant mutant of Clostridium acetobutylicum Rh8, from the wild type strain DSM 1731. Strain Rh8 can tolerate up to 19 g/L butanol, with solvent titer improved accordingly, thus exhibiting industrial application potential. To test if strain Rh8 can be used for production of high level mixed alcohols, a single secondary alcohol dehydrogenase from Clostridium beijerinckii NRRL B593 was overexpressed in strain Rh8 under the control of thl promoter. Results The heterogenous gene sADH was functionally expressed in C. acetobutylicum Rh8. This simple, one-step engineering approach switched the traditional ABE (acetone-butanol-ethanol) fermentation to IBE (isopropanol-butanol-ethanol) fermentation. The total alcohol titer reached 23.88 g/l (7.6 g/l isopropanol, 15 g/l butanol, and 1.28 g/l ethanol) with a yield to glucose of 31.42%. The acid (butyrate and acetate) assimilation rate in isopropanol producing strain Rh8(psADH) was increased. Conclusions The improved butanol tolerance and the enhanced solvent biosynthesis machinery in strain Rh8 is beneficial for production of high concentration of mixed alcohols. Strain Rh8 can thus be considered as a good host for further engineering of solvent/alcohol production. PMID:22742819

  20. Model predictive control algorithms and their application to a continuous fermenter

    Directory of Open Access Journals (Sweden)

    R. G. SILVA

    1999-06-01

    Full Text Available In many continuous fermentation processes, the control objective is to maximize productivity per unit time. The optimum operational point in the steady state can be obtained by maximizing the productivity rate using feed substrate concentration as the independent variable with the equations of the static model as constraints. In the present study, three model-based control schemes have been developed and implemented for a continuous fermenter. The first method modifies the well-known dynamic matrix control (DMC algorithm by making it adaptive. The other two use nonlinear model predictive control algorithms (NMPC, nonlinear model predictive control for calculation of control actions. The NMPC1 algorithm, which uses orthogonal collocation in finite elements, acted similar to NMPC2, which uses equidistant collocation. These algorithms are compared with DMC. The results obtained show the good performance of nonlinear algorithms.

  1. Influence of yeast immobilization on fermentation and aldehyde reduction during the production of alcohol-free beer

    NARCIS (Netherlands)

    Iersel, van M.F.M.; Brouwer-Post, E.; Rombouts, F.M.; Abee, T.

    2000-01-01

    Production of alcohol-free beer by limited fermentation is optimally performed in a packed-bed reactor. This highly controllable system combines short contact times between yeast and wort with the reduction of off-flavors to concentrations below threshold values. In the present study, the influence

  2. A comparison of fermentation in the cyanobacterium Microcystis PCC7806 grown under a light/dark cycle and continuous light

    NARCIS (Netherlands)

    Moezelaar, R.; Stal, L.J.

    1997-01-01

    The cyanobacterium Microcystis PCC7806, grown under continuous light, fermented endogenously stored glycogen to equimolar amounts of acetate and ethanol when incubated anaerobically in the dark. In addition, H-2, CO2 and some L-lactate were produced. This fermentation pattern differed from that disp

  3. Process of preparing ethanol by continuous fermentation of polysaccharide-containing materials

    Energy Technology Data Exchange (ETDEWEB)

    Ehnstroem, L.K.J.

    1981-04-16

    The invention concerns a process of preparing ethanol by continuous fermentation of polysaccharide - containing raw materials. Fermentation, hereby, occurs in one or several fermentors while dividing one stream of the fermentation liquid into a yeast-concentrate stream and a yeast-free stream and, if neccessary, a sludge stream. The yeast-concentrate stream is re-fed into the fermentor and at least part of the yeast-free stream is directed into a simple evaporator corresponding to one or several distilling stages where it is separated partially in an ethanol-enriched initial vapour stream supplying a facility to produce the desired ethanol quality, and partially in a liquid initial bottom stream re-fed at least in part into the fermentor. The characteristic feature of this new process is that a raw-material stream is fed into a closed circuit containing the fermentor and the evaporator, and that, in the evaporator, the raw-material stream is hydrolysed to a fermentable state. This hydrolysis is carried out most favourably by enzymes - preferably a gluco-amylase - at a temperature ranging from 35/sup 0/C to 75/sup 0/C.

  4. Improvement of a continuous ethanol fermentation from sweet sorghum stem juice using a cell recycling system.

    Science.gov (United States)

    Thani, Arthit; Laopaiboon, Pattana; Laopaiboon, Lakkana

    2017-06-10

    The process variables (aeration rate and recycle ratio) of a continuous ethanol fermentation with a cell recycling system (CRS) by Saccharomyces cerevisiae NP 01 from sweet sorghum stem juice were optimized using response surface methodology (RSM). The relationship between intracellular composition and fermentation efficiency was also investigated. RSM results revealed that the optimum aeration rate and recycle ratio were 0.25vvm and 0.625, respectively. The validation experiment under the optimum conditions indicated high precision and reliability of the experiment, achieving an actual ethanol concentration (PE) of 99.28g/l, which was very close to the predicted value (98.01g/l), and a very high ethanol productivity (QP) of 7.94g/lh. The intracellular composition of the yeast cells (i.e., unsaturated fatty acids (UFAs), total fatty acids (TFAs), ergosterol and trehalose) was positively related to the fermentation efficiency and yeast adaptive response under ethanol stress. A higher ratio of UFAs/TFAs and ergosterol strongly promoted yeast viability and ethanol fermentation. Additionally, high trehalose content was observed when the yeast was subjected to stress conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Aptitude of Saccharomyces yeasts to ferment unripe grapes harvested during cluster thinning for reducing alcohol content of wine.

    Science.gov (United States)

    Bovo, Barbara; Nadai, Chiara; Vendramini, Chiara; Fernandes Lemos Junior, Wilson Josè; Carlot, Milena; Skelin, Andrea; Giacomini, Alessio; Corich, Viviana

    2016-11-07

    Among the viticultural techniques developed to obtain wine with reduced alcohol content, the use of unripe grapes with low sugar and high malic acid concentration, harvested at cluster thinning, was recently explored. So far, no studies have evaluated the fermentation performances of Saccharomyces in unripe grape musts, in terms of fermentation ability and reducing malic acid contents, to improve the quality of this low-alcohol beverage. In this work, we evaluated 24 S. cerevisiae strains isolated from Italian and Croatian vineyards with different fermentation aptitudes. Moreover, four S. paradoxus were considered, as previous works demonstrated that strains belonging to this species were able to degrade high malic acid amounts in standard musts. The industrial strain S. cerevisiae 71B was added as reference. Sugar and malic acid contents were modified in synthetic musts in order to understand the effect of their concentrations on alcoholic fermentation and malic acid degradation. S. cerevisiae fermentation performances improved when glucose concentration decreased and malic acid level increased. The conditions that simulate unripe grape must, i.e. low glucose and high malic acid content were found to enhance S. cerevisiae ability to degrade malic acid. On the contrary, S. paradoxus strains were able to degrade high amounts of malic acid only in conditions that resemble ripe grape must, i.e. high glucose and low malic acid concentration. In fermentation trials when low glucose concentrations were used, at high malic acid levels S. cerevisiae strains produced higher glycerol than at low malic acid condition. Malic acid degradation ability, tested on the best performing S. cerevisiae strains, was enhanced in fermentation trials when unripe grape must was used.

  6. Control of fermentation types in continuous-flow acidogenic reactors: effects of pH and redox potential

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The experiments were carried out in continuous-flow acidogenic reactors with molasses used as sub strate to study the effects of pH and redox potential on fermentation types. The conditions for each fermentation type were investigated at different experimental stages of start-up, pH-regulating and redox potential-regulating.The experiments confirmed that butyric acid-type fermentation would occur at pH > 6, the propionic acid-type fermentation at pH about 5.5 with Eh > - 278 mV, and the ethanol-type fermentation at pH < 4.5. A higher redox potential will lead to propionic acid-type fermentation because propionogens are facultative anaerobic bacteria.

  7. Pre-alcoholic fermentation acidification of red grape must using Lactobacillus plantarum.

    Science.gov (United States)

    Onetto, Cristóbal A; Bordeu, Edmundo

    2015-12-01

    Red grape musts from overripe grapes are characterised by high pH and sugar concentration. Corrections with organic acids are commonly used to secure the alcoholic fermentation and improve the organoleptic characteristics of the wine. In this study we test an alternative biological acidification method using the ability of Lactobacillus plantarum to produce high concentrations of lactic acid. The time course of sugars, organic acids and pH were measured. Available sugars were consumed by L. plantarum producing up to 8.3 g L(-1) of lactic acid. Lactic acid changed the pH from 3.9 to 3.4 after 14 days post-inoculation without yielding a relevant concentration of acetic acid (0.34 g L(-1)).

  8. Supervisory System and Multivariable Control Applying Weighted Fuzzy-PID Logic in an Alcoholic Fermentation Process

    Directory of Open Access Journals (Sweden)

    Márcio Mendonça

    2015-10-01

    Full Text Available In this work, it is analyzed a multivariate system control of an alcoholic fermentation process with no minimum phase. The control is made with PID classic controllers associated with a supervisory system based on Fuzzy Systems. The Fuzzy system, a priori, send set-points to PID controllers, but also adds protection functions, such as if the biomass valued is at zero or very close. The Fuzzy controller changes the campaign to prevent or mitigate the paralyzation of the process. Three control architectures based on Fuzzy Control Systems are presented and compared in performance with classic control in different campaigns. The third architecture, in particular, adds an adaptive function. A brief summary of Fuzzy theory and correlated works will be presented. And, finally simulations results, conclusions and future works end the article.

  9. Adapting to alcohol: Dwarf hamster (Phodopus campbelli) ethanol consumption, sensitivity, and hoard fermentation.

    Science.gov (United States)

    Lupfer, Gwen; Murphy, Eric S; Merculieff, Zoe; Radcliffe, Kori; Duddleston, Khrystyne N

    2015-06-01

    Ethanol consumption and sensitivity in many species are influenced by the frequency with which ethanol is encountered in their niches. In Experiment 1, dwarf hamsters (Phodopus campbelli) with ad libitum access to food and water consumed high amounts of unsweetened alcohol solutions. Their consumption of 15%, but not 30%, ethanol was reduced when they were fed a high-fat diet; a high carbohydrate diet did not affect ethanol consumption. In Experiment 2, intraperitoneal injections of ethanol caused significant dose-related motor impairment. Much larger doses administered orally, however, had no effect. In Experiment 3, ryegrass seeds, a common food source for wild dwarf hamsters, supported ethanol fermentation. Results of these experiments suggest that dwarf hamsters may have adapted to consume foods in which ethanol production naturally occurs.

  10. Transformation of chemical constituents of lychee wine by simultaneous alcoholic and malolactic fermentations.

    Science.gov (United States)

    Chen, Dai; Liu, Shao-Quan

    2016-04-01

    This work examined for the first time the impact of malolactic fermentation (MLF) on the chemical constituents of lychee wine. Oenococcus oeni Viniflora Oenos (MLF inducer) and Saccharomyces cerevisiae MERIT.ferm were co-inoculated into lychee juice to induce simultaneous alcoholic fermentation (AF) and MLF. MLF did not affect sugar utilisation and ethanol production statistically (8.54% v/v for MLF and 9.27% v/v for AF). However, MLF resulted in dramatic degradation of malic and citric acids with concomitant increases of lactic acid, ethyl lactate and pH. The final concentrations of acetic and succinic acids between AF and MLF wines had no significant difference. The MLF wine contained significantly higher amounts of amino acids than the AF wine. More importantly, MLF significantly elevated the levels of potent aroma-active compounds including isoamyl acetate, linalool, geraniol and cis-rose oxide (to levels above or near respective detection thresholds), suggesting that MLF is an effective way of retaining the original lychee flavour.

  11. Efficiency of Blenke cascade system for continuous bio-ethanol fermentation.

    Science.gov (United States)

    Ntihuga, Jean Nepomuscene; Senn, Thomas; Gschwind, Peter; Kohlus, Reinhard

    2012-11-01

    A gas lift-system with inserts (so-called Blenke cascade system) for continuous bio-ethanol fermentation was constructed. Gas introduced at the bottom of the column created toroidal vortices in the fluid cells between inserts, enhancing mixing and improving residence time behavior without stirring equipment being necessary. The parameters mash type, start-up strategy, yeast-recycle model and yeast separation were studied concerning the efficiency of the ethanol production. The best results obtained were for a filtered mash, a double saccharification principle (DSP), a batch start-up strategy, an activation-recycle model and a lamella settler connected in series with a small conventional gravitational settler for yeast cells separation. Using this system, the fermentation residence time was τ=4-5.5h, depending on substrate type. Eighty five percent of the yeast cells could be separated. High volumetric ethanol productivity (Q(p)=20.43g/Lh) and yield E(y)=98% were achieved. Continuous fermentation, yeast recycling and sedimentation were contamination-free processes.

  12. Continuous gas fermentation by Acetobacterium woodii in a submerged membrane reactor with full cell retention.

    Science.gov (United States)

    Kantzow, Christina; Mayer, Alexander; Weuster-Botz, Dirk

    2015-10-20

    Acetogenic bacteria like Acetobacterium woodii represent an ancient group of anaerobic microorganisms which use hydrogen and carbon dioxide to produce acetate. Cell concentrations and space-time yields are usually low in gas fermentations. A standard stirred‑tank bioreactor with continuous gas supply was equipped with a customized submerged microfiltration unit. A. woodii showed similar growth behavior with an initial maximal growth rate of 1.2 d(-1) in continuous gas fermentations with full cell retention and varying dilution rates. A steady increase of cell mass concentrations was observed with the highest biomass formation at the highest dilution rate. By contrast the final acetate concentrations were lowest at the highest dilution rate. The highest final acetate space-time yield of 148 g l(-1) d(-1) was measured at the highest dilution rate (increase by factor 8 compared to a standard batch process or by factor 37 compared to published data). The highest reported cell concentration of A. woodii in gas fermentations of nearly 14 g l(-1) cell dry weight was achieved in the submerged membrane bioreactor with increased yeast extract concentrations in the feed medium. Product inhibition was observed when acetate concentrations exceeded 8-12 g l(-1) causing a steady decrease in cell mass specific acetate production rates.

  13. 流加比对双流加糖蜜酒精连续发酵的影响%Effect of Feeding Rate on Dual Stream Alcoholic Fermentation of Molasses

    Institute of Scientific and Technical Information of China (English)

    黄衡; 陆美艳; 甘美慢; 黄仁; 王文坚

    2014-01-01

    糖蜜酒精发酵目前多采用双流加连续发酵工艺,其高低浓糖蜜稀释的流加比例对糖蜜连续发酵有重要影响。本文通过糖蜜发酵试验的方式,对不同流加比的投料方式进行简单分析,总结不同流加方式对糖蜜酒精连续发酵的影响。结果表明在相同的平均锤度下,低浓的比例越大时,发酵的时间也越短,出酒率也相对越高。%Continuous dual stream alcoholic fermentation processes are widely used on molasses currently. During this procedure, the proportion of the high and low molasses diluent is important. This article on the alcoholic fermentation processes of molasses, will serve to analyze and summarize different feeding methods and the effect of continuous dual stream alcohol fermentation. Results indicate that under the same average Brix, low concentration ratio results in shorter fermentation times. The rate of wine is also relatively higher.

  14. A pulsing device for packed-bed bioreactors. Pt. 2; Application to alcoholic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Sanroman, A. (Chemical Engineering Dept., Univ. of Santiago de Compostela (Spain)); Roca, E. (Chemical Engineering Dept., Univ. of Santiago de Compostela (Spain)); Nunez, M.J. (Chemical Engineering Dept., Univ. of Santiago de Compostela (Spain)); Lema, J.M. (Chemical Engineering Dept., Univ. of Santiago de Compostela (Spain))

    1994-02-01

    When the immobilized cells are employed in packed-bed bioreactors several problems appear. To overcome these drawbacks, a new bioreactor based on the use of pulsed systems was developed. In this work, we study the glucose fermentation by immobilized Saccharomyces cerevisiae in a packed-bed bioreactor. A comparative study was then carried out for continuous fermentation in two packed-bed bioreactors, one of them with pulsed flow. The determination of the axial dispersion coefficients indicates that by introducing the pulsation, the hydraulic behaviour is closer to the plug flow model. In both cases, the residence time tested varied from 0.8 to 2.6 h. A higher ethanol concentration and productivity (increases up to 16%) were achieved with the pulsated reactors. The volumes occupied by the CO[sub 2] were 5.22% and 9.45% for fermentation with/without pulsation respectively. An activity test of the particles from the different sections revealed that the concentration and viability of bioparticles from the two bioreactors are similar. From the results we conclude that the improvements of the process are attributable to a mechanical effect rather than to physiological changes of microorganisms. (orig.)

  15. Effect of alcoholic fermentation in the content of phenolic compounds in cider processing

    Directory of Open Access Journals (Sweden)

    Alessandro Nogueira

    2008-10-01

    Full Text Available The objective of this work was to study the effect of alcoholic fermentation on the content of phenol compounds of five cider apple varieties. The initial content in the apple juice samples, as determined by HPLC, varied from 188.4 to 2776.17 m mg.L-1. In three of them (DC, PJ, GU, the total phenol compounds remained unaffected by fermentation. However, in two (DM, KE, the final values were lower (55 and 313 mg.L-1. In these apple cider, the values of caffeic acid increased from 6.6 mg.L-1 to 41.8 mg.L-1. The catechin content increased during the process, approximately 13 mg.L-1 independent of the variety. The other phenols class did not present any modifications due to the alcoholic fermentation, maintaining the phenolic compounds of original clarified apple juice in the cider.O objetivo deste trabalho foi estudar o efeito da fermentação alcoólica no teor de compostos fenólicos de cinco mostos de maçãs industriais. Os compostos fenólicos foram analisados por HPLC. Os mostos apresentaram fenóis totais entre 188,4 a 2776,17 mg.L-1. Os teores de fenóis durante a fermentação permaneceram os mesmos para as variedades DC, PJ e GU, entretanto, em DM e KE foi observada uma diminuição dos teores de fenóis (55 e 313 mg.L-1, respectivamente. Em KE o teor do ácido caféico aumentou de 6,6 mg.L-1 para 41,8 mg.L-1. O teor de catequinas aumentou cerca de 13 mg.L-1 durante o processo, independente da variedade. As outras classes de fenóis não apresentaram modificações com a fermentação alcoólica, permanecendo na sidra os compostos fenólicos do suco de maçã clarificado.

  16. Monitoring of alcoholic fermentation using near infrared and mid infrared spectroscopies combined with electronic nose and electronic tongue

    Energy Technology Data Exchange (ETDEWEB)

    Buratti, S., E-mail: susanna.buratti@unimi.it [Department of Food Science and Technology, Universita degli Studi di Milano, Via Celoria 2, 20133 Milano (Italy); Ballabio, D. [Department of Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milano (Italy); Giovanelli, G. [Department of Food Science and Technology, Universita degli Studi di Milano, Via Celoria 2, 20133 Milano (Italy); Dominguez, C.M. Zuluanga [Instituto de Ciencia y Tecnologia de Alimentos, Universidad Nacional de Colombia, Ciudad Universitaria, Bogota (Colombia); Moles, A.; Benedetti, S.; Sinelli, N. [Department of Food Science and Technology, Universita degli Studi di Milano, Via Celoria 2, 20133 Milano (Italy)

    2011-07-04

    Graphical abstract: Application of non destructive methods for the monitoring of red wine fermentation in correlation with the evolution of chemical parameters. Highlights: > We monitored time-related changes in red wine fermentation process. > NIR and MIR spectroscopies, electronic nose and tongue were applied. > Data were kinetically modelled to identify critical points during fermentation. > NIR, MIR electronic nose and tongue were able to follow the fermentation process. > The models agreed with the evolution of chemical parameters. - Abstract: Effective fermentation monitoring is a growing need due to the rapid pace of change in the wine industry, which calls for fast methods providing real time information in order to assure the quality of the final product. The objective of this work is to investigate the potential of non-destructive techniques associated with chemometric data analysis, to monitor time-related changes that occur during red wine fermentation. Eight micro-fermentation trials conducted in the Valtellina region (Northern Italy) during the 2009 vintage, were monitored by a FT-NIR and a FT-IR spectrometer and by an electronic nose and tongue. The spectroscopic technique was used to investigate molecular changes, while electronic nose and electronic tongue evaluated the evolution of the aroma and taste profile during the must-wine fermentation. Must-wine samples were also analysed by traditional chemical methods in order to determine sugars (glucose and fructose) consumption and alcohol (ethanol and glycerol) production. Principal Component Analysis was applied to spectral, electronic nose and electronic tongue data, as an exploratory tool, to uncover molecular, aroma and taste modifications during the fermentation process. Furthermore, the chemical data and the PC1 scores from spectral, electronic nose and electronic tongue data were modelled as a function of time to identify critical points during fermentation. The results showed that NIR and MIR

  17. Markers for detecting alcoholism and monitoring for continued abuse.

    Science.gov (United States)

    Morgan, M Y

    1980-01-01

    Several biochemical and haematological abnormalities are associated with excessive alcohol intake and some are used in the recognition and management of alcoholics. The ideal biological marker for detecting and monitoring alcoholics should be sensitive and highly specific for alcohol abuse; its value should be affected by changes in alcohol intake over relatively short periods of time and it should be quick, simple, convenient and inexpensive to estimate. At the present time no simple reliable marker is available which fulfills these criteria. Measurements of serum aspartate transaminase, serum gamma-glutamyl-transpeptidase and mean corpuscular volume are of proven value however and the majority of alcoholics can be detected and monitored by combining the measurements of these three tests. Blood/breath alcohol measurements are of limited value for detection but are useful for follow up. Measurement of the plasma alpha-amino-n-butyric acid/leucine ratio is of disputed value and not likely to be of great practical use. Measurement of serum alpha-lipoproteins, erythrocyte delta-aminolaevulinic acid dehydrase activity and qualitative estimation of serum transferrin have all been proposed as markers for alcohol abuse and are currently under evaluation.

  18. Continuous hydrogen production during fermentation of alpha-cellulose by the thermophillic bacterium Clostridium thermocellum.

    Science.gov (United States)

    Magnusson, Lauren; Cicek, Nazim; Sparling, Richard; Levin, David

    2009-02-15

    Continuous hydrogen (H2) production during fermentation of alpha-cellulose was established using the thermophillic, anaerobic bacterium Clostridium thermocellum ATCC 27405. The objectives of this work were to characterize growth of C. thermocellum, quantify H2 production and determine soluble end-product synthesis patterns during fermentation of a cellulosic substrate under continuous culture conditions. A 5 L working volume fermentor was established and growth experiments were maintained for over 3,000 h. Substrate concentrations were varied from 1 to 4 g/L and the feed was introduced with continuous nitrogen gas sparging to prevent clogging of the feed-line. The pH and temperature of the reactor were maintained at 7.0 and 600 degrees C, respectively, throughout the study. At concentrations above 4 g/L, the delivery of alpha-cellulose was impaired due to feed-line clogging and it became difficult to maintain a homogenous suspension. The highest total gas (H2 plus CO2) production rate, 56.6 mL L(-1) h(-1), was observed at a dilution rate of 0.042 h(-1) and substrate concentration of 4 g/L. Under these conditions, the H2 production rate was 5.06 mmol h(-1). Acetate and ethanol were the major soluble end-products, while lactate and formate were greatly reduced compared to production in batch cultures. Concentrations of all metabolites increased with increasing substrate concentration, with the exception of lactate. Despite a number of short-term electrical and mechanical failures during the testing period, the system recovered quickly, exhibiting substantial robustness. A carbon balance was completed to ensure that all end-products were accounted for, with final results indicating near 100% carbon recovery. This study shows that long-term, stable H2 production can be achieved during direct fermentation of an insoluble cellulosic substrate under continuous culture conditions.

  19. Optimisation of the alcoholic fermentation of aqueous jerivá pulp extract

    Directory of Open Access Journals (Sweden)

    Guilherme Arielo Rodrigues Maia

    2014-05-01

    Full Text Available The objective of this research is to determinate the optimum conditions for the alcoholic fermentation process of aqueous jerivá pulp extract using the response surface methodology and simplex optimisation technique. The incomplete factorial design 3³ was applied with the yeast extract, NH4H2PO4 and yeast as the independent variables and the alcohol production yield as the response. The regression analysis indicated that the model is predictive, and the simplex optimisation generated a formulation containing 0.35 g L-1 yeast extract, 6.33 g L-1 yeast and 0.30 g L-1NH4H2PO4 for an optimum yield of 85.40% ethanol. To validate the predictive equation, the experiment was carried out in triplicate under optimum conditions, and an average yield of 87.15% was obtained. According to a t-test, no significant difference was observed (on the order of 5% between the average value obtained and the value indicated by the simplex optimisation technique.

  20. Analysis of bacterial community during the fermentation of pulque, a traditional Mexican alcoholic beverage, using a polyphasic approach.

    Science.gov (United States)

    Escalante, Adelfo; Giles-Gómez, Martha; Hernández, Georgina; Córdova-Aguilar, María Soledad; López-Munguía, Agustín; Gosset, Guillermo; Bolívar, Francisco

    2008-05-31

    In this study, the characterization of the bacterial community present during the fermentation of pulque, a traditional Mexican alcoholic beverage from maguey (Agave), was determined for the first time by a polyphasic approach in which both culture and non-culture dependent methods were utilized. The work included the isolation of lactic acid bacteria (LAB), aerobic mesophiles, and 16S rDNA clone libraries from total DNA extracted from the maguey sap (aguamiel) used as substrate, after inoculation with a sample of previously produced pulque and followed by 6-h fermentation. Microbiological diversity results were correlated with fermentation process parameters such as sucrose, glucose, fructose and fermentation product concentrations. In addition, medium rheological behavior analysis and scanning electron microscopy in aguamiel and during pulque fermentation were also performed. Our results showed that both culture and non-culture dependent approaches allowed the detection of several new and previously reported species within the alpha-, gamma-Proteobacteria and Firmicutes. Bacteria diversity in aguamiel was composed by the heterofermentative Leuconostoc citreum, L. mesenteroides, L. kimchi, the gamma-Proteobacteria Erwinia rhapontici, Enterobacter spp. and Acinetobacter radioresistens. Inoculation with previously fermented pulque incorporated to the system microbiota, homofermentative lactobacilli related to Lactobacillus acidophilus, several alpha-Proteobacteria such as Zymomonas mobilis and Acetobacter malorum, other gamma-Proteobacteria and an important amount of yeasts, creating a starting metabolic diversity composed by homofermentative and heterofermentative LAB, acetic and ethanol producing microorganisms. At the end of the fermentation process, the bacterial diversity was mainly composed by the homofermentative Lactobacillus acidophilus, the heterofermentative L. mesenteroides, Lactococcus lactis subsp. lactis and the alpha-Proteobacteria A. malorum. After

  1. Two-stage continuous fermentation of Saccharomycopsis fibuligeria and Candida utilis.

    Science.gov (United States)

    Admassu, W; Korus, R A; Heimsch, R C

    1983-11-01

    Biomass production and carbohydrate reduction were determined for a two-stage continuous fermentation process with a simulated potato processing waste feed. The amylolytic yeast Saccharomycopsis fibuligera was grown in the first stage and a mixed culture of S. fibuligera and Candida utilis was maintained in the second stage. All conditions for the first and second stages were fixed except the flow of medium to the second stage was varied. Maximum biomass production occurred at a second stage dilution rate, D(2), of 0.27 h (-1). Carbohydrate reduction was inversely proportional to D(2), between 0.10 and 0.35 h (-1).

  2. Continuous high-solids corn liquefaction and fermentation with stripping of ethanol.

    Science.gov (United States)

    Taylor, Frank; Marquez, Marco A; Johnston, David B; Goldberg, Neil M; Hicks, Kevin B

    2010-06-01

    Removal of ethanol from the fermentor during fermentation can increase productivity and reduce the costs for dewatering the product and coproduct. One approach is to recycle the fermentor contents through a stripping column, where a non-condensable gas removes ethanol to a condenser. Previous research showed that this approach is feasible. Savings of $0.03 per gallon were predicted at 34% corn dry solids. Greater savings were predicted at higher concentration. Now the feasibility has been demonstrated at over 40% corn dry solids, using a continuous corn liquefaction system. A pilot plant, that continuously fed corn meal at more than one bushel (25 kg) per day, was operated for 60 consecutive days, continuously converting 95% of starch and producing 88% of the maximum theoretical yield of ethanol. A computer simulation was used to analyze the results. The fermentation and stripping systems were not significantly affected when the CO(2) stripping gas was partially replaced by nitrogen or air, potentially lowering costs associated with the gas recycle loop. It was concluded that previous estimates of potential cost savings are still valid.

  3. Continuous acetone-ethanol-butanol fermentation by immobilized cells of Clostridium acetobutylicum

    Energy Technology Data Exchange (ETDEWEB)

    Badr, H.R.; Toledo, R.; Hamdy, M.K. [University of Georgia, Athens (Greece). Food Science and Technology Dept.

    2001-07-01

    Eight Clostridium acetobutylicum strains were examined for {alpha}-amylase and strains B-591, B-594 and P-262 had the highest activities. Defibered-sweet-potato-slurry (DSPS), containing 39.7 g starch l{sup -1}, supplemented with potassium phosphate (1.0 g l{sup -1}), cysteine-HCl (5.0 g l{sup -1}), the antifoam (polypropylene glycol, 0.1 mg ml{sup -1}), was used a continuous feedstock (FS) to a multistage bioreactor system for acetone-ethanol-butanol (AEB) fermentation. The system consisted on four columns (three vertical and one near horizontal) packed with beads containing immobilized cells of C. acetobutylicum P-262. When DSPS was pumped into the bioreactor system, at a flow rate of 2.36 ml min{sup -1}, the effluent has 7.73 g solvents l{sup -1} (1.56, acetone; 0.65, ethanol; 5.52 g, butanol) and no starch. Productivity of total solvents synthesized during continuous operation were 1.0 g 1{sup -1}h{sup -1} and 19.5 % yield compared to 0.12 g l{sup -1}h{sup -1} with 29% yield using the batch system. We proposed using DSPS for AEB fermentation in a continuous mode with immobilized P-262 cells that are active amylase producers which will lead to cost reduction compared to the batch system. (Author)

  4. An exploratory study assessing reasons behind initiation, continuation or stoppage of alcohol after first use

    Directory of Open Access Journals (Sweden)

    B S Chavan

    2015-01-01

    Full Text Available Objective: Few studies have investigated the reasons for alcohol initiation and continuation. The present study examined reasons for trying alcohol for the first time and its subsequent use. Furthermore, the study attempted to discover the possible predictors that make an individual vulnerable to alcohol use. Methodology: A total of 280 first-year college students from six different colleges were contacted. Using the method of equal probability, every third subject from each class was selected. All the selected subjects were interviewed and administered semi-structured questionnaire for gathering information regarding their experience with alcohol. Results: In our study, experimentation and peer pressure were found to be the main reasons for both alcohol use and its re-use. The first time drinkers differed a lot from those with multiple users in terms of reasons for trying alcohol, the effect of alcohol, family history of alcohol use, and self-view about alcohol use. The results depicted that the gender, educational stream, and family history of alcohol use are the factors that make an individual vulnerable to alcohol use. Conclusion: First-year of college is a unique transitional period. First-year students with high levels of sensation seeking may be especially at high-risk to begin or escalate heavy drinking. Studying the nature of alcohol initiation may not only be helpful in planning awareness programs but also in preventing underage drinking and alcohol abuse.

  5. Low fermentation pH is a trigger to alcohol production, but a killer to chain elongation

    Directory of Open Access Journals (Sweden)

    Ramon eGanigué

    2016-05-01

    Full Text Available Gasification of organic wastes coupled to syngas fermentation allows the recovery of carbon in the form of commodity chemicals, such as carboxylates and biofuels. Acetogenic bacteria ferment syngas to mainly two-carbon compounds, although a few strains can also synthesize four-, and six-carbon molecules. In general, longer carbon chain products have a higher biotechnological (and commercial value due to their higher energy content and their lower water solubility. However, de-novo synthesis of medium-chain products from syngas is quite uncommon in bacteria. An alternative to de-novo synthesis is bioproduction of short-chain products (C2 and C4, and their subsequent elongation to C4, C6 or C8 through reversed β-oxidation metabolism. This two-step synergistic approach has been successfully applied for the production of up to C8 compounds, although, the accumulation of alcohols in these mixed cultures remained below detection limits. The present work investigates the production of higher alcohols from syngas by open mixed cultures (OMC. A syngas-fermenting community was enriched from sludge of an anaerobic digester for a period of 110 days in a lab-scale reactor. At the end of this period, stable production of ethanol and butanol was obtained. C6 compounds were only transiently produced at the beginning of the enrichment phase, during which Clostridium kluyveri, a bacterium able to carry out carbon chain elongation, was detected in the community. Further experiments showed pH as a critical parameter to maintain chain elongation activity in the co-culture. Production of C6 compounds was recovered by preventing fermentation pH to decrease below pH 4.5-5. Finally, experiments showed maximal production of C6 compounds (0.8 g/L and alcohols (1.7 g/L of ethanol, 1.1 g/L of butanol and 0.6 g/L of hexanol at pH 4.8. In conclusion, low fermentation pH is critical for the production of alcohols, although detrimental to C. kluyveri. Fine control of

  6. Acetaldehyde kinetics of enological yeast during alcoholic fermentation in grape must.

    Science.gov (United States)

    Li, Erhu; Mira de Orduña, Ramón

    2017-02-01

    Acetaldehyde strongly binds to the wine preservative SO2 and, on average, causes 50-70 mg l(-1) of bound SO2 in red and white wines, respectively. Therefore, a reduction of bound and total SO2 concentrations necessitates knowledge of the factors that affect final acetaldehyde concentrations in wines. This study provides a comprehensive analysis of the acetaldehyde production and degradation kinetics of 26 yeast strains of oenological relevance during alcoholic fermentation in must under controlled anaerobic conditions. Saccharomyces cerevisiae and non-Saccharomyces strains displayed similar metabolic kinetics where acetaldehyde reached an initial peak value at the beginning of fermentations followed by partial reutilization. Quantitatively, the range of values obtained for non-Saccharomyces strains greatly exceeded the variability among the S. cerevisiae strains tested. Non-Saccharomyces strains of the species C. vini, H. anomala, H. uvarum, and M. pulcherrima led to low acetaldehyde residues (<10 mg l(-1)), while C. stellata, Z. bailii, and, especially, a S. pombe strain led to large residues (24-48 mg l(-1)). Acetaldehyde residues in S. cerevisiae cultures were intermediate and less dispersed (14-34 mg l(-1)). Addition of SO2 to Chardonnay must triggered significant increases in acetaldehyde formation and residual acetaldehyde. On average, 0.33 mg of residual acetaldehyde remained per mg of SO2 added to must, corresponding to an increase of 0.47 mg of bound SO2 per mg of SO2 added. This research demonstrates that certain non-Saccharomyces strains display acetaldehyde kinetics that would be suitable to reduce residual acetaldehyde, and hence, bound-SO2 levels in grape wines. The acetaldehyde formation potential may be included as strain selection argument in view of reducing preservative SO2 concentrations.

  7. [Effect of Bacillus natto-fermented product (BIOZYME) on blood alcohol, aldehyde concentrations after whisky drinking in human volunteers, and acute toxicity of acetaldehyde in mice].

    Science.gov (United States)

    Sumi, H; Yatagai, C; Wada, H; Yoshida, E; Maruyama, M

    1995-04-01

    Effects of Bacillus natto-fermented product (BIOZYME) on blood alcohol and aldehyde concentrations after drinking whisky (corresponding to 30-65 ml ethanol) were studied in 21 healthy volunteers. When 100 ml of BIOZYME was orally administrated to the volunteers before drinking whisky, the time delay of both blood factors to attain maximum concentrations were observed. The maximum decrease in blood alcohol and aldehyde concentrations were about 23% and 45% (p whisky. The aldehyde lowering effect of BIOZYME was continued for at least 4 hr after whisky drinking. Concentration of the breath alcohol was also sharply decreased by BIOZYME administration. The breath alcohol concentration in the administered group (0.18 +/- 0.11 mg/l) was found to be lowered about 44% than that of the control group (0.32 +/- 0.11 mg/l) (p whisky. In acute toxicity experiments of aldehyde in mice (12 mmol AcH/mg), BIOZYME showed the survival effect as with alpha-D-Ala (134% increase of the living, at 40 min after i.p. administration) (p < 0.005, n = 22). These findings reveal the Bacillus natto produced BIOZYME as a reasonable, safety and useful anti-hangover agent.

  8. Amino acid content in red wines obtained from grapevine nitrogen foliar treatments: consumption during the alcoholic fermentation

    Directory of Open Access Journals (Sweden)

    Javier Portu

    2014-12-01

    Full Text Available Nitrogen is an important element for grapevine and winemaking which affects the development of the plant and yeast, and therefore it is important for wine quality. The aim of this work was to study the influence of foliar application to vineyard of proline, phenylalanine and urea and two commercial nitrogen fertilizers, without and with amino acids in their formulation, on the wine amino acid content and their consumption during the alcoholic fermentation. The results showed that these treatments did not affect the amino acid composition in wines. The differences observed for certain amino acids were so small that the concentration of total amino acids was not significantly different among wines. Moreover, it was observed that the higher the content of amino acids in the medium, the greater their consumption during the alcoholic fermentation.

  9. Butanol production by immobilised Clostridium acetobutylicum in repeated batch, fed-batch, and continuous modes of fermentation.

    Science.gov (United States)

    Dolejš, Igor; Krasňan, Vladimír; Stloukal, Radek; Rosenberg, Michal; Rebroš, Martin

    2014-10-01

    Clostridium acetobutylicum immobilised in polyvinylalcohol, lens-shaped hydrogel capsules (LentiKats(®)) was studied for production of butanol and other products of acetone-butanol-ethanol fermentation. After optimising the immobilisation protocol for anaerobic bacteria, continuous, repeated batch, and fed-batch fermentations in repeated batch mode were performed. Using glucose as a substrate, butanol productivity of 0.41 g/L/h and solvent productivity of 0.63 g/L/h were observed at a dilution rate of 0.05 h(-1) during continuous fermentation with a concentrated substrate (60 g/L). Through the process of repeated batch fermentation, the duration of fermentation was reduced from 27.8h (free-cell fermentation) to 3.3h (immobilised cells) with a solvent productivity of 0.77 g/L/h (butanol 0.57 g/L/h). The highest butanol and solvent productivities of 1.21 and 1.91 g/L/h were observed during fed-batch fermentation operated in repeated batch mode with yields of butanol (0.15 g/g) and solvents (0.24 g/g), respectively, produced per gram of glucose.

  10. Influence of heat shock-treated cells on the production of glycerol and other metabolites in alcoholic fermentation

    Directory of Open Access Journals (Sweden)

    Sofoklis Petropoulos

    2010-11-01

    Full Text Available Sofoklis Petropoulos1,2, Paul R Grbin2, Vladimir Jiranek21SEMELI SA, Stamata Attica, Greece; 1,2School of Agriculture, Food and Wine, The University of Adelaide, South Australia, AustraliaAbstract: The impact of heat shock on the formation of sensorily important fermentation metabolites was investigated. Initially the heat tolerance of six commercial Saccharomyces cerevisiae yeast strains was evaluated under various conditions of time and temperature (heat shock at 40°C, 50°C, and 60°C for a duration of 20, 40, and 60 minutes, respectively. A chemically defined grape juice medium was inoculated from the surviving colonies, and microferments were conducted. Two strains were selected for further evaluation due to their heat shock tolerance and enhanced glycerol production. The experiment was repeated in standard laboratory scale fermentations under aerobic and anaerobic conditions, and the medium was inoculated directly after the heat shock treatment and after recovery from the heat shock on yeast peptone dextrose plates. All fermentations were further analyzed for higher alcohol, organic acid, and ethyl ester content using gas chromatography mass spectrometry. Elevated glycerol production (increase of 17% under aerobic conditions and 8% under anaerobic conditions was reported only in one strain and only after direct inoculation of the fermentation medium. With both strains, direct inoculation of the heated cells caused a 2-day delay in the commencement of the fermentation, but after recovery, the fermentation progress was increased. Volatile analysis showed that apart from changes in organic acids, all other volatile compounds analyzed exhibited an alteration mainly due to strain differences and the presence of oxygen.Keywords: heat shock, glycerol, higher alcohols, wine, Saccharomyces

  11. Isolation, identification and optimization of ethanol producing bacteria from Saccharomyces-based fermentation process of alcohol industries in Iran

    Directory of Open Access Journals (Sweden)

    Hoda Ebrahimi

    2013-01-01

    Full Text Available Introduction: Due to the vast growth of world population, consumption of a lot of energy, limited energy supply and rising prices of fuel oil in the future, other alternative energy source is essential. Ethanol is renewable and a safe fuel and it is mainly based on microbial fermentation. The purpose of this study was isolation of high ethanol producing bacteria from the fermentation process of alcohol industries and optimization of growth conditions to be introduced to the industries. Materials and methods: The samples that were collected from fermentation tanks of alcohol industries were enriched in ZSM medium. To isolate the ethanol producing bacteria, the enriched culture was transferred on RMA agar. Bacterial growth conditions and their effects on ethanol production were optimized based on pH, growth temperature, agitation, fermentation time, initial substrate concentration and carbon and nitrogen sources. In addition, the morphological, physiological and molecular characterizations were investigated for identification of the isolates.Results: Three bacterial isolates ZYM7, ZYM8 and ZYM9 were isolated from fermentation tank. All isolates were able to produce ethanol 5.00, 7.60 and 4.00 gL-1 after 48 hours, respectively. The results demonstrated that all isolates were able to consume most sugars sources specially pentose carbon xylose. The isolate ZYM7 produced 13.00 gL-1 ethanol by consumption of xylose. The results of morphological and physiological characteristics showed that ZYM7 belonged to Lactobacillus sp. and ZYM8 and ZYM9 belonged to Acetobacter sp. Moreover, 16S rRNA sequencing and phylogenetic analyses exhibited that ZYM7 was similar to Lactobacillus rhamnosus with 99% homology and ZYM8 and ZYM9 were similar to Acetobacter pasteurianus with 99 and 98% homology, respectively.Discussion and conclusion: The results showed that that the isolated bacteria were suitable candidates to produce ethanol from raw material enriched with

  12. Improvement of alcoholic fermentation by calcium ions under enological conditions involves the increment of plasma membrane H(+)-ATPase activity.

    Science.gov (United States)

    Li, Jingyuan; Huang, Weidong; Wang, Xiuqin; Tang, Tian; Hua, Zhaozhe; Yan, Guoliang

    2010-07-01

    The effect of Ca(2+) on alcoholic fermentation and plasma membrane H(+)-ATPase activity of wine yeast under enological conditions were investigated in this study. The results showed that fermentation rate, cell growth and ethanol production were improved by 0.5 and 1.5 mM Ca(2+) supplementation, which correlated well with the increment of ATPase activity and protein levels. Considering the important role of ATPase in the tolerance of yeast to ethanol, the improvement could be, at least partially, attributed to the increment of ATPase activity. No activation of ATPase by Ca(2+) was observed in the early phase of fermentation and the increment of activity was only observed when ethanol concentration exceeded 6.5%. Therefore, the enhancement of ATPase activity by Ca(2+) was ascribed to alleviating the inhibition of ATPase activity by ethanol through protection of membrane structure. Our results suggest that, besides maintenance of cell membrane structure, the increment of plasma membrane ATPase activity was also responsible for the improvement of alcoholic fermentation by Ca(2+) supplementation.

  13. The Effect of DL-Malic Acid on the Metabolism of L-Malic Acid during Wine Alcoholic Fermentation

    Directory of Open Access Journals (Sweden)

    Fabio Coloretti

    2002-01-01

    Full Text Available Insufficient wine acidity can affect wine quality and stability. To overcome this problem, DL-malic acid can be added to the grape juice prior to fermentation. We have investigated the effect of DL-malic acid on wine fermentations and its influence on the final concentration of L-malic acid, naturally present in grape juice. To this end yeast strains that metabolise L-malic acid in different ways were tested and compared; namely, Schizosaccharomyces pombe (efficient L-malic acid degrader, Saccharomyces cerevisiae (non-degrader, hybrid strain S. cerevisiae x S. uvarum (intermediate degrader and Saccharomyces uvarum (promoting L-malic acid synthesis. In all cases, D-malic acid passively entered the yeast cells and did not undergo malo-alcoholic fermentation. However, its presence in the juice, as a component of the mixture of D- and L- malic acid (DL-malic acid, reduced the amount of L-malic acid that can be degraded or synthesised by yeasts during malo-alcoholic fermentation.

  14. In-situ combination of fermentation and electrodialysis with bipolar membranes for the production of lactic acid: continuous operation.

    Science.gov (United States)

    Wang, Xiaolin; Wang, Yaoming; Zhang, Xu; Feng, Hongyan; Xu, Tongwen

    2013-11-01

    An experimental study was carried out to achieve a continuous integrated operation of fermentation and electrodialysis with bipolar membranes (EDBM). There need three steps to accomplish this experiment: (1) individual continuous fermentation; (2) individual continuous EDBM; (3) integrated operation of fermentation and EDBM under continuous condition. The results indicate that the maximum feed rate (fermenter can afford) is 0.24 L/h, which is also equal to the feed rate of the subsequent individual continuous EDBM. During continuous EDBM, the recovery ratio of lactate from the fermentation broth can reach 69.5% under a current density of 40 mA/cm(2). The net end concentration and total molar quantity for lactic acid can reach 1.46 mol/L and 2.18 mol, and for OH(-) are 1.32 mol/L and 1.70 mol, respectively. The integration can be achieved only under an initial alkali concentration of no less than 1 mol/L and a current density of no less than 30 mA/cm(2). Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Process optimization of continuous gluconic acid fermentation by isolated yeast-like strains of Aureobasidium pullulans.

    Science.gov (United States)

    Anastassiadis, Savas; Aivasidis, Alexander; Wandrey, Christian; Rehm, Hans-Jürgen

    2005-08-20

    This study was focused on the optimization of a new fermentation process for continuous gluconic acid production by the isolated yeast-like strain Aureobasidium pullulans DSM 7085 (isolate 70). Operational fermentation parameters were optimized in chemostat cultures, using a defined glucose medium. Different optima were found for growth and gluconic acid production for each set of operation parameters. Highest productivity was recorded at pH values between 6.5 and 7.0 and temperatures between 29 and 31 degrees C. A gluconic acid concentration higher than 230 g/L was continuously produced at residence times of 12 h. A steady state extracellular gluconic acid concentration of 234 g/L was measured at pH 6.5. 122% air saturation yielded the highest volumetric productivity and product concentration. The biomass-specific productivity increased steadily upon raising air saturation. An intracellular gluconic acid concentration of about 159 g/L (0.83 mol) was determined at 31 degrees C. This is to be compared with an extracellular concentration of 223 g/L (1.16 mol), which indicates the possible existence of an active transport system for gluconic acid secretion, or the presence of extracellular glucose oxidizing enzymes. The new process provides significant advantages over the traditional discontinuous fungi operations. The process control becomes easier, thus offering stable product quality and quantity.

  16. Impact of available nitrogen and sugar concentration in musts on alcoholic fermentation and subsequent wine spoilage by Brettanomyces bruxellensis.

    Science.gov (United States)

    Childs, Bradford C; Bohlscheid, Jeffri C; Edwards, Charles G

    2015-04-01

    The level of yeast assimilable nitrogen (YAN) supplementation required for Saccharomyces cerevisiae to complete fermentation of high sugar musts in addition to the impact of non-metabolized nitrogen on post-alcoholic spoilage by Brettanomyces bruxellensis was studied. A 2 × 3 factorial design was employed using a synthetic grape juice medium with YAN (150 or 250 mg N/L) and equal proportions of glucose/fructose (230, 250, or 270 g/L) as variables. S. cerevisiae ECA5 (low nitrogen requirement) or Uvaferm 228 (high nitrogen requirement) were inoculated at 10(5) cfu/mL while B. bruxellensis E1 or B2 were added once alcoholic fermentation ceased. Regardless of YAN concentration, musts that contained 230 or 250 g/L glucose/fructose at either nitrogen level attained dryness (mean = 0.32 g/L fructose) while those containing 270 g/L generally did not (mean = 2.5 g/L fructose). Higher concentrations of YAN present in musts yielded wines with higher amounts of α-amino acids and ammonium but very little (≤ 6 mg N/L) was needed by B. bruxellensis to attain populations ≥ 10(7) cfu/mL. While adding nitrogen to high sugar musts does not necessarily ensure completion of alcoholic fermentation, residual YAN did not affect B. bruxellensis growth as much as ethanol concentration.

  17. Lignocellulose fermentation and residual solids characterization for senescent switchgrass fermentation by Clostridium thermocellum in the presence and absence of continuous in situ ball-milling

    Energy Technology Data Exchange (ETDEWEB)

    Balch, Michael L.; Holwerda, Evert K.; Davis, Mark F.; Sykes, Robert W.; Happs, Renee M.; Kumar, Rajeev; Wyman, Charles E.; Lynd, Lee R.

    2017-04-12

    Milling during lignocellulosic fermentation, henceforth referred to as cotreatment, is investigated as an alternative to thermochemical pretreatment as a means of enhancing biological solubilization of lignocellulose. We investigate the impact of milling on soluble substrate fermentation by Clostridium thermocellum with comparison to yeast, document solubilization for fermentation of senescent switchgrass with and without ball milling, and characterize residual solids. Soluble substrate fermentation by C. thermocellum proceeded readily in the presence of continuous ball milling but was completely arrested for yeast. Total fractional carbohydrate solubilization achieved after fermentation of senescent switchgrass by C. thermocellum for 5 days was 0.45 without cotreatment or pretreatment, 0.81 with hydrothermal pretreatment (200 degrees C, 15 minutes, severity 4.2), and 0.88 with cotreatment. Acetate and ethanol were the main fermentation products, and were produced at similar ratios with and without cotreatment. Analysis of solid residues was undertaken using molecular beam mass spectrometry (PyMBMS) and solid-state nuclear magnetic resonance spectroscopy (NMR) in order to provide insight into changes in plant cell walls during processing via various modes. The structure of lignin present in residual solids remaining after fermentation with cotreatment appeared to change little, with substantially greater changes observed for hydrothermal pretreatment - particularly with respect to formation of C-C bonds. The observation of high solubilization with little apparent modification of the residue is consistent with cotreatment enhancing solubilization primarily by increasing the access of saccharolytic enzymes to the feedstock, and C. thermocellum being able to attack all the major linkages in cellulosic biomass provided that these linkages are accessible.

  18. 酒精醋发酵条件的研究%Study on the Fermentation Conditions of Alcohol Vinegar

    Institute of Scientific and Technical Information of China (English)

    李历; 郭会明; 洪厚胜

    2014-01-01

    The effects of four factors such as liquid volume,inoculum size,initial acetic content and in-itial alcohol content on the acid-producing amount of acetic acid fermentation with acetic acid bacteria as fermentation strains and food-grade alcohol as raw material are studied.The optimal conditions of acetic acid fermentation are:100 mL/500 mL of liquid volume,10% of inoculum size,1% of initial acetic content and 5%of initial alcohol content.Besides,the acidity changes during the process of ace-tic fermentation are also investigated.It is found that the initial alcohol degree and initial acetic con-tent have greater impact on acetic acid production at the beginning of fermentation,while inoculum size place the most important role near the end of fermentation.%以醋酸菌为发酵菌株,食品级酒精为原料,考察了装液量、接种量、初始底酸量和初始酒精度四个因素对醋酸发酵最终的产酸量的影响,利用正交试验、极差分析法和方差分析,确定了酒精醋发酵最佳条件为装液量100 mL/500 mL、接种量10%、初始底酸量1%、初始酒精度5%。同时考察了醋酸发酵过程中酸度的变化情况,发现在醋酸发酵的开始阶段初始酒精度、初始底酸量对其影响较大,而在发酵后期,接种量影响较大。

  19. Switchgrass (Panicum virgatum) fermentation by Clostridium thermocellum and Clostridium saccharoperbutylacetonicum sequential culture in a continuous flow reactor

    Science.gov (United States)

    The study was conducted to evaluate fermentation by Clostridium thermocellum and C. saccharoperbutylacetonicum in a continuous-flow, high-solids reactor. Liquid medium was continuously flowed through switchgrass (2 mm particle size) at one of three flow rates: 83.33 mL h-1 (2 L d-1), 41.66 mL h-1(1 ...

  20. Application of microbial electrolysis cells to treat spent yeast from an alcoholic fermentation.

    Science.gov (United States)

    Sosa-Hernández, Ornella; Popat, Sudeep C; Parameswaran, Prathap; Alemán-Nava, Gibrán Sidney; Torres, César I; Buitrón, Germán; Parra-Saldívar, Roberto

    2016-01-01

    Spent yeast (SY), a major challenge for the brewing industry, was treated using a microbial electrolysis cell to recover energy. Concentrations of SY from bench alcoholic fermentation and ethanol were tested, ranging from 750 to 1500mgCOD/L and 0 to 2400mgCOD/L respectively. COD removal efficiency (RE), coulombic efficiency (CE), coulombic recovery (CR), hydrogen production and current density were evaluated. The best treatment condition was 750mgCOD/LSY+1200mgCOD/L ethanol giving higher COD RE, CE, CR (90±1%, 90±2% and 81±1% respectively), as compared with 1500mgCOD/LSY (76±2%, 63±7% and 48±4% respectively); ethanol addition was significantly favorable (p value=0.011), possibly due to electron availability and SY autolysis. 1500mgCOD/LSY+1200mgCOD/L ethanol achieved higher current density (222.0±31.3A/m(3)) and hydrogen production (2.18±0.66 [Formula: see text] ) but with lower efficiencies (87±2% COD RE, 71.0±.4% CE). Future work should focus on electron sinks, acclimation and optimizing SY breakdown.

  1. Yeast contribution to melatonin, melatonin isomers and tryptophan ethyl ester during alcoholic fermentation of grape musts.

    Science.gov (United States)

    Vigentini, Ileana; Gardana, Claudio; Fracassetti, Daniela; Gabrielli, Mario; Foschino, Roberto; Simonetti, Paolo; Tirelli, Antonio; Iriti, Marcello

    2015-05-01

    Melatonin (MEL) has been found in some medicinal and food plants, including grapevine, a commodity of particular interest for the production of wine, a beverage of economic relevance. It has also been suggested that MEL in wine may, at least in part, contribute to the health-promoting properties attributed to this beverage and, possibly, to other traditional Mediterranean foodstuffs. After a preliminary screening of 9 yeast strains in laboratory medium, three selected strains (Saccharomyces cerevisiae EC1118, Torulaspora delbrueckii CBS1146(T) and Zygosaccharomyces bailii ATCC36947(T) ) were inoculated in experimental musts obtained from 2 white (Moscato and Chardonnay) and 2 red (Croatina and Merlot) grape varieties. The production of MEL, melatonin isomers (MIs) and tryptophan ethyl ester (TEE) was monitored during the alcoholic fermentation. The screening showed that the three investigated strains produced the highest concentrations of MEL and two MIs in optimal growth conditions. However, MEL and MIs were not produced in oenological conditions, but the three strains synthesized high concentrations of a new MI and TEE in musts.

  2. Use of virginiamycin to control the growth of lactic acid bacteria during alcohol fermentation.

    Science.gov (United States)

    Hynes, S H; Kjarsgaard, D M; Thomas, K C; Ingledew, W M

    1997-04-01

    The antibiotic virginiamycin was investigated for its effects on growth and lactic acid production by seven strains of lactobacilli during the alcoholic fermentation of wheat mash by yeast. The lowest concentration of virginiamycin tested (0.5 mg Lactrol kg-1 mash), was effective against most of the lactic acid bacteria under study, but Lactobacillus plantarum was not significantly inhibited at this concentration. The use of virginiamycin prevented or reduced potential yield losses of up to 11% of the produced ethanol due to the growth and metabolism of lactobacilli. However, when the same concentration of virginiamycin was added to mash not inoculated with yeast, Lactobacillus rhamnosus and L. paracasei grew after an extensive lag of 48 h and L. plantarum grew after a similar lag even in the presence of 2 mg virginiamycin kg-1 mash. Results showed a variation in sensitivity to virginiamycin between the different strains tested and also a possible reduction in effectiveness of virginiamycin over prolonged incubation in wheat mash, especially in the absence of yeast.

  3. Effect of ammonium concentration on alcoholic fermentation kinetics by wine yeasts for high sugar content.

    Science.gov (United States)

    Taillandier, Patricia; Ramon Portugal, Felipe; Fuster, André; Strehaiano, Pierre

    2007-02-01

    Kinetics of alcoholic fermentation by Saccharomyces cerevisiae wine strains in a synthetic medium with high sugar content were established for different nitrogen initial content and are presented for four strains. The composition of the medium was close to grape must except that the nitrogen source consisted mainly in ammonium and was varied from 120 to 290 mg N/l assimilable nitrogen. The overall nitrogen consumed was also estimated in order to determine nitrogen requirement variability. The effect of assimilable nitrogen was in general greater on sugar consumption rates than on growth and three kinds of effect on sugar consumption rates were observed: (i) existence of an optimal initial nitrogen level for a maximal sugar consumption rate (inhibition if excess), (ii) no effect of nitrogen beyond the intermediary level (saturation), (iii) sugar consumption rate proportional to the initial nitrogen level (activation). In all cases, the amount of consumed nitrogen increased with its initial concentration and so did the fructophilic capacity of the strains. The optimal requirement varied from 0.62 to 0.91 mg N/g of sugars according to different strains. There was no general correlation between the sugar assimilation rates and the nitrogen requirement.

  4. Effects of type of carbohydrate supplementation to lush pasture on microbial fermentation in continuous culture.

    Science.gov (United States)

    Bach, A; Yoon, I K; Stern, M D; Jung, H G; Chester-Jones, H

    1999-01-01

    Eight single-flow continuous culture fermenters were used to study the effects of the type of energy source on ruminal N utilization from high quality pasture. The four dietary treatments included high quality grass and legume pasture alone (50:50; wt/wt), pasture plus soybean hulls, pasture plus beet pulp, and pasture plus corn. Diets supplemented with additional sources of energy (soybean hulls, beet pulp, and corn) were isocaloric but differed in the type and rate of carbohydrate fermentation. Energy supplements constituted 45% of the total dietary dry matter and were fed twice daily at 12-h intervals in place of pasture, which is characteristic of grain feeding at milking when animals are in a grazing situation. Energy supplementation reduced pH, NH3 N flow, and NH3 N concentration and increased bacterial N flow (as a percentage of N intake). The supplementation of corn and soybean hulls resulted in the highest microbial N flow (as a percentage of N intake). Corn had a tendency to reduce fiber digestion because of excessively low NH3 N concentrations. Beet pulp was similar to corn in that it decreased NH3 N concentrations. Supplementation of soybean hulls resulted in a more synchronized fermentation, greater volatile fatty acid production, and greater fiber digestion. Nitrogen utilization by microbes was maximized by supplementation with soybean hulls or corn twice a day. With diets based on pasture, it may be more important to improve bacterial N flow and bacterial utilization of N than to maximize the efficiency of bacterial protein synthesis because better utilization of N by ruminal microorganisms results in higher bacterial N flow and higher fiber digestion.

  5. Production and characterization of distilled alcoholic beverages obtained by solid-state fermentation of black mulberry (Morus nigra L.) and black currant (Ribes nigrum L.).

    Science.gov (United States)

    Alonso González, Elisa; Torrado Agrasar, Ana; Pastrana Castro, Lorenzo M; Orriols Fernández, Ignacio; Pérez Guerra, Nelson

    2010-02-24

    The present study was conducted to appraise the potential of black mulberry and black currant to be used as fermentation substrates for producing alcoholic beverages obtained by distillation of the fruits previously fermented with Sacchromyces cerevisiae IFI83. In the two distillates obtained, the volatile compounds that can pose health hazards are within the limits of acceptability fixed by the European Council (Regulation 110/2008) for fruit spirits. However, the amount of volatile substances in the black currant distillate (121.1 g/hL absolute alcohol (aa)) was lower than the minimum limit (200 g/hL aa) fixed by the aforementioned regulation. The mean volatile composition of both distillates was different from other alcoholic beverages such as four commercial Galician orujo spirits, Portuguese bagaceiras, and two distillates obtained from fermented whey and blackberry. The results obtained showed the feasibility for obtaining distillates from fermented black mulberry and black currant, which have their own distinctive characteristics.

  6. Kinetics of D-glucose and D-fructose conversion during the alcoholic fermentation promoted by Saccharomyces cerevisiae.

    Science.gov (United States)

    Zinnai, Angela; Venturi, Francesca; Sanmartin, Chiara; Quartacci, Mike F; Andrich, Gianpaolo

    2013-01-01

    Although many studies on the different aspects of alcoholic fermentation are available in the literature, it is still difficult to identify the possible causes of the slowing-down or stuck of fermentations, even if the change of some compositional parameters (D-glucose/D-fructose and glycerine produced/hexoses converted ratios) could be assumed as sound signals of a possible deviation from the usual Saccharomyces metabolic pathways. The reason why alcoholic yeasts preferably metabolise D-glucose rather than D-fructose was investigated by a kinetic model based on six functional parameters having a well-defined chemical-physical meaning. The time evolution of different initial concentrations of D-glucose and D-fructose, dissolved in a model solution simulating a must (citrate buffer at pH 3.4 inoculated by a commercial strain of Saccharomyces cerevisiae), was investigated adding or not ethanol to the reaction medium. When a reduced amount of ethanol was dissolved in the reaction medium, the time evolution of the fermentation rates of these two sugars did not differ significantly, to diversify rather strongly when the alcoholic concentration increased. The hypothesised mathematical model accounts for this particular kinetic behaviour. In fact, only the sensitivity to ethanol showed by the enzymatic protein involved in the limiting steps of the fermentation process of these two sugars differed significantly, the enzymatic transformation of D-fructose being more sensitive to ethanol than D-glucose. This difference was able to justify the different kinetic behaviours shown by the two sugars when ethanol concentration in the reaction medium increased.

  7. Modeling and Parameter Identification Involving 3-Hydroxypropionaldehyde Inhibitory Effects in Glycerol Continuous Fermentation

    Directory of Open Access Journals (Sweden)

    Zhaohua Gong

    2012-01-01

    Full Text Available Mathematical modeling and parameter estimation are critical steps in the optimization of biotechnological processes. In the 1,3-propanediol (1,3-PD production by glycerol fermentation process under anaerobic conditions, 3-hydroxypropionaldehyde (3-HPA accumulation would arouse an irreversible cessation of the fermentation process. Considering 3-HPA inhibitions to cells growth and to activities of enzymes, we propose a novel mathematical model to describe glycerol continuous cultures. Some properties of the above model are discussed. On the basis of the concentrations of extracellular substances, a parameter identification model is established to determine the kinetic parameters in the presented system. Through the penalty function technique combined with an extension of the state space method, an improved genetic algorithm is then constructed to solve the parameter identification model. An illustrative numerical example shows the appropriateness of the proposed model and the validity of optimization algorithm. Since it is difficult to measure the concentrations of intracellular substances, a quantitative robustness analysis method is given to infer whether the model is plausible for the intracellular substances. Numerical results show that the proposed model is of good robustness.

  8. [Continuous operation of hydrogen bio-production reactor with ethanol-type fermentation].

    Science.gov (United States)

    Ren, Nan-qi; Gong, Man-li; Xing, De-feng

    2004-11-01

    The natural response of a continuous stirred tank reactor (CSTR) for hydrogen bio-production using molasses wastewater as substrate was investigated. Emphasis was placed on assessing the operational controlling strategy on the stable operation of CSTR with high efficiency. It was found that at an initial biomass of 15g/L, an equilibrial microbial community in the ethanol-type fermentation and efficient stable operation of CSTR could be established with following conditions: temperature of 35 degrees C +/- 1 degrees C, COD organic loading rate (OLR) of 40kg/(m3 x d), hydraulic retention time (HRT) of 4h, pH value of 4.6 - 4.9 and oxidation reduction potential (ORP) of -450 - -470mV. Following that, hydrogen production in the reactor was relatively stable. The observed maximal hydrogen bio-production rate was 7.63m3/(m3 x d). The content of hydrogen in the biogas was about 40% - 58%. COD removal rate was between 22% - 26%. The total content of ethanol and acetic acid in the fermentative end products was above 80%.

  9. Involvement of branched-chain amino acid aminotransferases in the production of fusel alcohols during fermentation in yeast

    Energy Technology Data Exchange (ETDEWEB)

    Eden, A.; Drukker, M.; Benvenisty, N. [Hebrew Univ., Jerusalem (Israel). Dept. of Genetics; Nedervelde, L. van; Debourg, A. [Haute Ecole Lucia de Brouckere, Brussels (Belgium). Dept. of Brewing Sciences and Fermentation Technology

    2001-07-01

    Organoleptic compounds produced by yeast during the fermentation of wort have a great impact on beer smell and taste. Among them, fusel alcohols are the major abundant volatile compounds. The availability of Saccharomyces cerevisiae mutants in which the genes coding for the two branched-chain amino acid aminotransferases have been deleted offers the possibility of further defining the role of these enzymes in the formation of higher alcohols. Comparing the production profiles of different strains, it is clear that they are not all influenced in the same way by branched-chain amino acid aminostransferase mutations. First of all, as propanol is synthesised from {alpha}-ketobutyrate, the first metabolic intermediate in the anabolic pathway of isoleucine, neither the eca39 nor eca40 mutations have any effect on the production of this higher alcohol. On the other hand, it can be concluded that the eca40 mutation has a drastic effect on the production of isobutanol. To a certain extent, the same conclusion can be made for the production of active amyl alcohol and isoamyl alcohol, although the results suggest that another route could lead to the formation of these two higher alcohols. (orig.)

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

    Science.gov (United States)

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

    2016-11-01

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

  11. Optimization of cyclosporin A production by Beauveria nivea in continuous fed-batch fermentation

    Directory of Open Access Journals (Sweden)

    Dong Huijun

    2011-01-01

    Full Text Available To develop the effective control method for fed-batch culture of cyclosporin A production, we chose fructose, L-valine and (NH42HPO4 as feeding nutrients and compared their productivities in relation to different concentrations. The feeding rate of three kinds of feeding materials was controlled to maintain the suitable residual concentration. The fed-batch fermentation results indicated that the optimal concentrations of fructose, L-valine and (NH42HPO4 were about 20 g/L, 0.5 g/L and 0.6 g/L for cyclosporin A production, respectively. The cultivation of Beauveria nivea could produce cyclosporin A up to 6.2 g/L for 240 hrs through a continuous feeding-rate-controlled-batch process under the optimal feeding conditions.

  12. Parameters of rumen fermentation in a continuously fed sheep: evidence of a microbial rumination pool.

    Science.gov (United States)

    Hungate, R E; Reichl, J; Prins, R

    1971-12-01

    The feed and feces of a continuously fed sheep were analyzed for carbon, hydrogen, and nitrogen, with oxygen as the remainder. The daily feed-feces weight difference was used as the reactant in an equation representing the rumen fermentation. The measured products were the daily production of volatile fatty acids (VFA), CH(4), CO(2), and ammonia. The carbon unaccounted for was assumed to be in the microbial cell material produced in the rumen and absorbed before reaching the feces. The ratio of C to H, O, and N in bacteria was used to represent the elemental composition of the microbes formed in the rumen fermentation, completing the following equation:C(20.03)H(36.99)O(17.406)N(1.345) + 5.65 H(2)O --> C(12)H(24)O(10.1) + 0.83 CH(4) VFA + 2.76 CO(2) + 0.50 NH(3) + C(4.44)H(8.88)O(2.35)N(0.785) microbial cells absorbed With C arbitrarily balanced and O balanced by appropriate addition of water, any error is reflected in the H. The H recovery was 98.5%. The turnover rate constant for rumen liquid equilibrating with polyethylene glycol (PEG) was 2.27 per day. Direct counts and volume measurements of the individual types of bacteria and protozoa in the rumen were used to calculate the total microbial cell volume in the rumen, not equilibrating with it. The dry matter in the rumen (582 g) and the nitrogen content (12.05) of the microbes in the rumen were estimated, the latter constituting 85% of the measured N in the rumen. Calculations for rumen dry matter and nitrogen turning over at the PEG rate introduce big discrepancies with other parameters; a rumination pool must be postulated. Its size and composition are estimated. Arguments are presented to support the view that dry matter and some of the microbes, chiefly the protozoa, do not leave the rumen at the PEG rate. One experiment with the same sheep fed twice daily showed significantly less production of microbial cells than did the continuous (each 2 hr) feeding. Analysis of the microbial cell yield suggests that

  13. Assessing the mechanisms responsible for differences between nitrogen requirements of saccharomyces cerevisiae wine yeasts in alcoholic fermentation.

    Science.gov (United States)

    Brice, Claire; Sanchez, Isabelle; Tesnière, Catherine; Blondin, Bruno

    2014-02-01

    Nitrogen is an essential nutrient for Saccharomyces cerevisiae wine yeasts during alcoholic fermentation, and its abundance determines the fermentation rate and duration. The capacity to ferment under conditions of nitrogen deficiency differs between yeasts. A characterization of the nitrogen requirements of a set of 23 strains revealed large differences in their fermentative performances under nitrogen deficiency, and these differences reflect the nitrogen requirements of the strains. We selected and compared two groups of strains, one with low nitrogen requirements (LNRs) and the other with high nitrogen requirements (HNRs). A comparison of various physiological traits indicated that the differences are not related to the ability to store nitrogen or the protein content. No differences in protein synthesis activity were detected between strains with different nitrogen requirements. Transcriptomic analysis revealed expression patterns specific to each of the two groups of strains, with an overexpression of stress genes in HNR strains and a stronger expression of biosynthetic genes in LNR strains. Our data suggest that differences in glycolytic flux may originate from variations in nitrogen sensing and signaling under conditions of starvation.

  14. Hepatoprotective Effect of Fermented Soybean (Nutrient Enriched Soybean Tempeh against Alcohol-Induced Liver Damage in Mice

    Directory of Open Access Journals (Sweden)

    Hamidah Mohd Yusof

    2013-01-01

    Full Text Available Recently, soybean tempeh has received great attention due to many advantages such as higher nutritional value, lower production cost, and shorter fermentation time. In this study, the in vivo hepatoprotective and antioxidant effects of nutrient enriched soybean tempeh (NESTE were determined. NESTE fermentation process which involved anaerobic incubation was previously proclaimed to increase the content of amino acids and antioxidant properties remarkably. The evaluation of histological sections, serum biochemical markers (aspartate aminotransferase (AST, alanine aminotransferase (ALT, and cholesterol and triglycerides (TG, liver immune response level (nitric oxide (NO and liver antioxidant level (superoxide dismutase (SOD, ferric reducing antioxidant power (FRAP, and malondialdehyde (MDA was conducted in order to compare the effects of nonfermented soybean extract (SBE and fermented soybean extract (NESTE on alcohol-induced liver damage in mice. Results demonstrated that 1000 mg/kg of NESTE can significantly reduce the levels of AST, ALT, cholesterol, TG, MDA, and NO. On the other hand, it also raised the level of SOD and FRAP. Furthermore, the histological examination on 1000 mg/kg NESTE treatment group showed that this extract was capable of recovering the damaged hepatocytes to their normal structures. Thus, it can be concluded that NESTE produced through fermentation process was able to enhance hepatoprotective and antioxidant effects in vivo.

  15. Optimization of Alcohol Fermentation Using Organic Nutrients%应用有机营养优化酒精发酵水平

    Institute of Scientific and Technical Information of China (English)

    刘劲松; 施清; 罗天; 邬善远; 李梅忠; 许引虎

    2016-01-01

    In this paper, the composition of yeast in alcohol fermentation was introduced including elements, content, and functions. In addi-tion, the working mechanism of organic nutrients in alcohol fermentation was elaborated. Especially, the measures of using fermentation nutri-ents to improve alcohol fermentation levels were put forward, including regulating raw material cooking and steaming techniques, changing fer-mentation starter indexes, cancelling acid addition, and changing nutritional structure, etc. The above measures might improve alcohol fermenta-tion in practice.%介绍了酒精发酵中酵母的组成,包括元素、含量以及作用.阐述了酒精发酵有机营养剂的机理,重点说明了应用发酵营养剂提高发酵酒精生产水平的措施,包括微调原料蒸煮工艺、改变成熟酒母指标、取消额外加酸、改变营养结构等方式,通过以上措施可实现指标优化.

  16. Bioaggregate of photo-fermentative bacteria for enhancing continuous hydrogen production in a sequencing batch photobioreactor.

    Science.gov (United States)

    Xie, Guo-Jun; Liu, Bing-Feng; Wang, Rui-Qing; Ding, Jie; Ren, Hong-Yu; Zhou, Xu; Ren, Nan-Qi

    2015-11-05

    Hydrogen recovery through solar-driven biomass conversion by photo-fermentative bacteria (PFB) has been regarded as a promising way for sustainable energy production. However, a considerable fraction of organic substrate was consumed for the growth of PFB as biocatalysts, furthermore, these PFB were continuously washed out from the photobioreactor in continuous operation because of their poor flocculation. In this work, PFB bioaggregate induced by L-cysteine was applied in a sequencing batch photobioreactor to enhance continuous hydrogen production and reduce biomass washout. The effects of the hydraulic retention time (HRT), influent concentration and light intensity on hydrogen production of the photobioreactor were investigated. The maximum hydrogen yield (3.35 mol H2/mol acetate) and production rate (1044 ml/l/d) were obtained at the HRT of 96 h, influent concentration of 3.84 g COD/l, and light intensity of 200 W/m(2). With excellent settling ability, biomass accumulated in the photobioreactor and reached 2.15 g/l under the optimum conditions. Structural analysis of bioaggregate showed that bacterial cells were covered and tightly linked together by extracellular polymeric substances, and formed a stable structure. Therefore, PFB bioaggregate induced by L-cysteine is an efficient strategy to improve biomass retention capacity of the photobioreactor and enhance hydrogen recovery efficiency from organic wastes.

  17. Non-linear multivariable predictive control of an alcoholic fermentation process using functional link networks

    Directory of Open Access Journals (Sweden)

    Luiz Augusto da Cruz Meleiro

    2005-06-01

    Full Text Available In this work a MIMO non-linear predictive controller was developed for an extractive alcoholic fermentation process. The internal model of the controller was represented by two MISO Functional Link Networks (FLNs, identified using simulated data generated from a deterministic mathematical model whose kinetic parameters were determined experimentally. The FLN structure presents as advantages fast training and guaranteed convergence, since the estimation of the weights is a linear optimization problem. Besides, the elimination of non-significant weights generates parsimonious models, which allows for fast execution in an MPC-based algorithm. The proposed algorithm showed good potential in identification and control of non-linear processes.Neste trabalho um controlador preditivo não linear multivariável foi desenvolvido para um processo de fermentação alcoólica extrativa. O modelo interno do controlador foi representado por duas redes do tipo Functional Link (FLN, identificadas usando dados de simulação gerados a partir de um modelo validado experimentalmente. A estrutura FLN apresenta como vantagem o treinamento rápido e convergência garantida, já que a estimação dos seus pesos é um problema de otimização linear. Além disso, a eliminação de pesos não significativos gera modelos parsimoniosos, o que permite a rápida execução em algoritmos de controle preditivo baseado em modelo. Os resultados mostram que o algoritmo proposto tem grande potencial para identificação e controle de processos não lineares.

  18. Operation of a two-stage continuous fermentation process producing hydrogen and methane from artificial food wastes

    Energy Technology Data Exchange (ETDEWEB)

    Nagai, Kohki; Mizuno, Shiho; Umeda, Yoshito; Sakka, Makiko [Toho Gas Co., Ltd. (Japan); Osaka, Noriko [Tokyo Gas Co. Ltd. (Japan); Sakka, Kazuo [Mie Univ. (Japan)

    2010-07-01

    An anaerobic two-stage continuous fermentation process with combined thermophilic hydrogenogenic and methanogenic stages (two-stage fermentation process) was applied to artificial food wastes on a laboratory scale. In this report, organic loading rate (OLR) conditions for hydrogen fermentation were optimized before operating the two-stage fermentation process. The OLR was set at 11.2, 24.3, 35.2, 45.6, 56.1, and 67.3 g-COD{sub cr} L{sup -1} day{sup -1} with a temperature of 60 C, pH5.5 and 5.0% total solids. As a result, approximately 1.8-2.0 mol-H{sub 2} mol-hexose{sup -1} was obtained at the OLR of 11.2-56.1 g-COD{sub cr} L{sup -1} day{sup -1}. In contrast, it was inferred that the hydrogen yield at the OLR of 67.3 g-COD{sub cr} L{sup -1} day{sup -1} decreased because of an increase in lactate concentration in the culture medium. The performance of the two-stage fermentation process was also evaluated over three months. The hydraulic retention time (HRT) of methane fermentation was able to be shortened 5.0 days (under OLR 12.4 g-COD{sub cr} L{sup -1} day{sup -1} conditions) when the OLR of hydrogen fermentation was 44.0 g-COD{sub cr} L{sup -1} day{sup -1}, and the average gasification efficiency of the two-stage fermentation process was 81% at the time. (orig.)

  19. Effect of pulsed electric field treatment during cold maceration and alcoholic fermentation on major red wine qualitative and quantitative parameters.

    Science.gov (United States)

    El Darra, Nada; Rajha, Hiba N; Ducasse, Marie-Agnès; Turk, Mohammad F; Grimi, Nabil; Maroun, Richard G; Louka, Nicolas; Vorobiev, Eugène

    2016-12-15

    This work studies the effect of pulsed electric field (PEF) treatment at moderate and high field strengths (E=0.8kV/cm & 5kV/cm) prior and during alcoholic fermentation (AF) of red grapes on improving different parameters of pre-treated extracts: pH, °Brix, colour intensity (CI), total polyphenols content (TPI) of Cabernet Sauvignon red wine. Similar trends were observed for treating grapes using moderate and high electric field strength on the enhancement of CI and TPI of the wine after AF. The application of PEF using moderate strengths at different times during cold maceration (CM) (0, 2 and 4days) was more efficient for treatment during CM. The treatment during AF showed lower extraction rate compared to treating during CM and prior to AF. Our results clearly show that the best time for applying the PEF-treatment through the red fermentation is during the CM step.

  20. Alcoholic fermentation under oenological conditions. Use of a combination of data analysis and neural networks to predict sluggish and stuck fermentations

    Energy Technology Data Exchange (ETDEWEB)

    Insa, G. [Inst. National de la Recherche Agronomique, Inst. des Produits de la Vigne, Lab. de Microbiologie et Technologie des Fermentations, 34 - Montpellier (France); Sablayrolles, J.M. [Inst. National de la Recherche Agronomique, Inst. des Produits de la Vigne, Lab. de Microbiologie et Technologie des Fermentations, 34 - Montpellier (France); Douzal, V. [Centre National du Machinisme Agricole du Genie Rural des Eaux et Forets, 92 - Antony (France)

    1995-09-01

    The possibility of predicting sluggish fermentations under oenological conditions was investigated by studying 117 musts of different French grape varieties using an automatic device for fermentation monitoring. The objective was to detect sluggish or stuck fermentations at the halfway point of fermentation. Seventy nine percent of fermentations were correctly predicted by combining data analysis and neural networks. (orig.)

  1. Cell wall polysaccharides released during the alcoholic fermentation by Schizosaccharomyces pombe and S. japonicus: quantification and characterization.

    Science.gov (United States)

    Domizio, P; Liu, Y; Bisson, L F; Barile, D

    2017-02-01

    The present work demonstrates that yeasts belonging to the Schizosaccharomyces genus release a high quantity of polysaccharides of cell wall origin starting from the onset of the alcoholic fermentation. By the end of the alcoholic fermentation, all of the Schizosaccharomyces yeast strains released a quantity of polysaccharides approximately 3-7 times higher than that released by a commercial Saccharomyces cerevisiae yeast strain under the same fermentative conditions of synthetic juice. A higher content of polysaccharide was found in media fermented by Schizosaccharomyces japonicus with respect to that of Schizosaccharomyces pombe. Some of the strains evaluated were also able to produce high levels of pyruvic acid, which has been shown to be an important compound for color stability of wine. The presence of strains with different malic acid consumption patterns along with high polysaccharide release would enable production of naturally modified wines with enhanced mouth feel and reduced acidity. The chemical analysis of the released polysaccharides demonstrated divergence between the two yeast species S. pombe and S. japonicus. A different mannose/galactose ratio and a different percentage of proteins was observed on the polysaccharides released by S. pombe as compared to S. japonicus. Analysis of the proteins released in the media revealed the presence of a glycoprotein with a molecular size around 32-33 kDa only for the species S. japonicus. Mass spectrometry analysis of carbohydrate moieties showed similar proportions among the N-glycan chains released in the media by both yeast species but differences between the two species were also observed. These observations suggest a possible role of rapid MALDI-TOF screening of N-glycans compositional fingerprint as a taxonomic tool for this genus. Polysaccharides release in the media, in particular galactomannoproteins in significant amounts, could make these yeasts particularly interesting also for the industrial

  2. Continuous acetone-butanol-ethanol (ABE) fermentation and gas production under slight pressure in a membrane bioreactor.

    Science.gov (United States)

    Chen, Chunyan; Wang, Linyuan; Xiao, Guoqing; Liu, Yucheng; Xiao, Zeyi; Deng, Qing; Yao, Peina

    2014-07-01

    Two rounds of acetone-butanol-ethanol (ABE) fermentation under slight pressure were carried out in the continuous and closed-circulating fermentation (CCCF) system. Spores of the clostridium were observed and counted, with the maximum number of 2.1 × 10(8) and 2.3 × 10(8)ml(-1) separately. The fermentation profiles were comparable with that at atmospheric pressure, showing an average butanol productivity of 0.14 and 0.13 g L(-1)h(-1). Moreover, the average gas productivities of 0.28 and 0.27 L L(-1)h(-1) were obtained in two rounds of CCCF, and the cumulative gas production of 52.64 and 25.92 L L(-1) were achieved, with the hydrogen volume fraction of 41.43% and 38.08% respectively. The results suggested that slight pressures have no obvious effect on fermentation performance, and also indicated the significance and feasibility of gas recovery in the continuous ABE fermentation process. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Study of process variables in industrial acetic fermentation by a continuous pilot fermentor and response surfaces.

    Science.gov (United States)

    Garrido-Vidal, Diego; Pizarro, Consuelo; González-Sáiz, José M

    2003-01-01

    The modeling and optimization of industrial processes requires an intensive study of the factors involved. In this work, a continuous pilot system for studying the industrial process of acetic fermentation is developed. A Doehlert design is applied to the five variables involved in the pilot process. This experimental design allows reduction of the experimental burden and the maximum amount of information to be obtained, studying the factors at different levels depending on their significance. The experimental system provides a robust measure of the specific growth rate and the rates of substrates consumption and acetic acid production, related to the flow of effluent stream evaluated in the steady state. The results demonstrate the growth-associated kinetics of substrates and product, and the yield factors are calculated with low values of variances for the coefficients, i.e., within the range 1-11%. The specific growth rate suits the quadratic model proposed. The response surfaces generated by the model are applied to explain the behavior of the bacterial growth and, therefore, the effects of the process variables studied over the acetic acid production. Very low levels of ethanol or oxygen make the acetification rate decrease, and a saturation effect with high levels of ethanol or oxygen is also deduced. The effects of the aeration rate, agitation, and overpressure suggest a kind of inhibition of the acetic acid production caused by the oxygen that has not been practically studied before. The temperature strengthens the inhibitory effect of the ethanol and the oxygen. The conclusions of this work consolidate the structure of a hybrid model for the acetic fermentation.

  4. Ethanol production from biomass by repetitive solid-state fed-batch fermentation with continuous recovery of ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Moukamnerd, Churairat; Kino-oka, Masahiro; Sugiyama, Minetaka; Kaneko, Yoshinobu; Harashima, Satoshi; Katakura, Yoshio [Osaka Univ. (Japan). Dept. of Biotechnology; Boonchird, Chuenchit [Mahidol Univ., Bangkok (Thailand). Dept. of Biotechnology; Noda, Hideo [Kansai Chemical Engineering Co., Ltd., Amagasaki (Japan); Ninomiya, Kazuaki [Kanazawa Univ. (Japan). Inst. of International Environment Technology; Shioya, Suteaki [Sojo Univ., Kumamoto (Japan). Dept. of Applied Life Science

    2010-09-15

    To save cost and input energy for bioethanol production, a consolidated continuous solid-state fermentation system composed of a rotating drum reactor, a humidifier, and a condenser was developed. Biomass, saccharifying enzymes, yeast, and a minimum amount of water are introduced into the system. Ethanol produced by simultaneous saccharification and fermentation is continuously recovered as vapor from the headspace of the reactor, while the humidifier compensates for the water loss. From raw corn starch as a biomass model, 95 {+-} 3, 226 {+-} 9, 458 {+-} 26, and 509 {+-} 64 g l{sup -1} of ethanol solutions were recovered continuously when the ethanol content in reactor was controlled at 10-20, 30-50, 50-70 and 75-85 g kg-mixture{sup -1}, respectively. The residue showed a lesser volume and higher solid content than that obtained by conventional liquid fermentation. The cost and energy for intensive waste water treatment are decreased, and the continuous fermentation enabled the sustainability of enzyme activity and yeast in the system. (orig.)

  5. 马铃薯渣发酵酒精的研究%Study on the Alcoholic Fermentation of Potato Residue

    Institute of Scientific and Technical Information of China (English)

    苏槟楠; 王慕华; 萧晋川; 徐宏英; 潘佩平; 蔡颖慧

    2011-01-01

    对马铃薯渣发酵酒精进行了研究,结果表明:马铃薯渣加水量占总量的80%时糖化效果较好,糖化时间以24h为宜;通过正交试验得知在马铃薯渣中加入KH2PO4对产酒率影响较大,最优组合为MgSO4·7H2O 0.5%、KH2PO4 0.3%、NH4 NO30.75%;通过酒精得率和还原糖残留量在不同发酵时间的变化,最后确定72 h为最终发酵时间.%The alcoholic fermentation of potato residue was studied. The results indicated that the saccharization was approving when the water reached to 80% of whole, and the optimum time of saccharization was 24 h. By orthogonal test, it was knowed that KH2PO4 was the most influence for the alcoholic yield and the best compounding was MgSO4 · 7H2O 0.5% 、KH2PO4 0.3% 、NH4N03 0.75%. By the change of the alcoholic output and the leftover reducing sugar in different time of fermentation, it was knowed that the final time of fermentation was 72 h.

  6. Application of hybrid yeasts for molasses fermentation during the production of alcohol and bakers' yeast

    Energy Technology Data Exchange (ETDEWEB)

    Raev, Z.A.; Kovalenko, A.D.; Korobkova, L.A.; Sadovnikova, T.A.; Bespalaya, M.K.

    1973-01-01

    Various hybrids of brewers yeasts were studied and their technological properties established. It was shown that hybrid 75 was suitable for increasing alcohol yields from molasses. Hybrid 112 was suitable for increasing the maltase activity of bakers' yeast. Efficient exploitation of the above properties of yeast hybrids may be achieved in a 2 stage molasses fermentation process developed at the Ukrainian Res. Inst. of Distillery Ind. The method is based on 2-stage yeast addition: strain B yeasts in the 1st stage and an appropriate hybrid in the second.

  7. 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 glu

  8. Degradation of aflatoxin B1 during the fermentation of alcoholic beverages.

    Science.gov (United States)

    Inoue, Tomonori; Nagatomi, Yasushi; Uyama, Atsuo; Mochizuki, Naoki

    2013-06-28

    Aflatoxin B1 (AFB1) is a contaminant of grain and fruit and has one of the highest levels of carcinogenicity of any natural toxin. AFB1 and the fungi that produce it can also contaminate the raw materials used for beer and wine manufacture, such as corn and grapes. Therefore, brewers must ensure strict monitoring to reduce the risk of contamination. In this study, the fate of AFB1 during the fermentation process was investigated using laboratory-scale bottom and top beer fermentation and wine fermentation. During fermentation, cool wort beer samples and wine must samples were artificially spiked with AFB1 and the levels of AFB1 remaining after fermentation were analyzed. AFB1 levels were unchanged during both types of fermentation used for beer but were reduced to 30% of their initial concentration in wine. Differential analysis of the spiked and unspiked wine samples showed that the degradation compound was AFB2a, a hydrated derivative of AFB1. Thus, the results showed that the risk of AFB1 carryover was still present for both types of beer fermentation but was reduced in the case of wine fermentation because of hydration.

  9. Studies of Saccharomyces cerevisiae and Non-Saccharomyces Yeasts during Alcoholic Fermentation

    DEFF Research Database (Denmark)

    Kemsawasd, Varongsiri

    The early death of non-Saccharomyces yeasts during mixed culture spontaneous wine fermentation has traditionally been attributed to the lower capacity of these yeast species to withstand high levels of ethanol, low pH, and other media properties that are a part of progressing fermentation. However......, other yeast-yeast interactions, such as cell-cell contact mediated growth arrest and/or toxininduced death may also be a significant factor in the relative fragility of these non-Saccharomyces yeasts in mixed culture fermentation. In the present work we evaluate the combined roles of cell-cell contact...... and/or antimicrobial peptides on the early death of Lachancea thermotolerans during mixed culture fermentations with Saccharomyces cerevisiae. Using a specially designed double compartment fermentation system, we established that both cell-to-cell contact and antimicrobial peptides contribute...

  10. Low-pressure airlift fermenter for single cell protein production: II. Continuous culture of Pichia yeast

    Energy Technology Data Exchange (ETDEWEB)

    Chen, N.Y.; Srinivasan, S.; Leavitt, R.I.; Coty, V.F.; Kondis, E.F.

    1987-03-01

    Experiments using Pichia yeast grown on n-paraffins have been conducted in laboratory 10-l airlift fermenters and in a 640-l module of commercial scale. Results confirmed the design concept with low-pressure air. However, in the absence of mass transport constraints, the build up of toxic factors in the fermenter appeared to a major variable limiting cell productivity. Foaming in the large fermenter also presented a serious problem, which must be solved before low-pressure airlift fermenters become practical. 14 references.

  11. Synergistic dark and photo-fermentation continuous system for hydrogen production from molasses by Clostridium acetobutylicum ATCC 824 and Rhodobacter capsulatus DSM 1710.

    Science.gov (United States)

    Morsy, Fatthy Mohamed

    2017-04-01

    This study investigated synergistic dark and photo-fermentation using continuous fermentation system (CFS). The system relies on connecting several fermenters from bottom of one to top culture level of the next in a manner that allows for delaying movement of the substrate and thus for its full consumption. While H2 was collected, CFS allowed for moving liquid byproducts toward the outlet and hence continuous productivity. CFS could be efficiently used for: (1) Continuous dark and photo-fermentation H2 production by Clostridium acetobutylicum and Rhodobacter capsulatus producing 5.65moleH2mole(-1) hexose; (2) Continuous dark-fermentation synergistic H2, acetone, butanol and ethanol (ABE) production by C. acetobutylicum which produced per mole hexose, 2.43mol H2 along with 73.08g ABE (3) Continuous H2 and methane production by C. acetobutylicum and bacterial sludge producing, per mole hexose, 1.64mol pure H2 and 2.56mol CH4 mixed with 0.37mol H2·The hydraulic retention time (HRT) for whole system was short where organic acids produced in dark-fermentation in first fermenter were synergistically utilized for H2 production by R. capsulatus in subsequent fermenters. CFS is suitable for fast-digestible sugars but not lignocelluloses or other hard-digestible organics, requiring prolonged HRT, unless such polymeric organics were hydrolyzed prior to fermentation. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. 酸枣果醋酒精发酵过程工艺的研究%Study on technology of alcohol fermentation in wild jujube vinegar

    Institute of Scientific and Technical Information of China (English)

    毛丽衡; 毛永民; 王颉; 申连英; 刘亚琼; 王晓玲

    2013-01-01

    以酸枣果肉为原料,采用液态酒精-固态醋酸发酵法研制果醋,对酸枣果醋酒精发酵的过程进行研究.通过单因素和正交实验,得出酒精发酵最佳发酵条件,即含糖量15%,温度29.℃,酵母接种量0.08%,pH3.5,磷酸氢二铵添加量4g/L,酒精度可达到8.7%.实验结果可以为酸枣果醋饮料产品的进一步开发提供一定依据.%Fruit vinegar was produced using wild jujube as a raw material after liquid fermentation of alcohol and solid fermentation of acetic acid.The main processing technology and conditions of alcohol fermentation were studied.By single factor experiment and the orthogonal experiment,the best alcohol fermentation conditions were obtained,for sugar 15%,fermentation temperature 29℃,inoculum concentration 0.08%,pH3.5,diammonium phosphate concentration 4g/L,the alcoholic strength could reach 8.7%.Results showed that these technology foundations could be used for the further development of lemon vinegar drinks.

  13. Analysis of low temperature-induced genes (LTIG) in wine yeast during alcoholic fermentation.

    Science.gov (United States)

    Chiva, Rosana; López-Malo, Maria; Salvadó, Zoel; Mas, Albert; Guillamón, Jósé Manuel

    2012-11-01

    Fermentations carried out at low temperatures, that is, 10-15 °C, not only enhance the production and retention of flavor volatiles, but also increase the chances of slowing or arresting the process. In this study, we determined the transcriptional activity of 10 genes that were previously reported as induced by low temperatures and involved in cold adaptation, during fermentation with the commercial wine yeast strain QA23. Mutant and overexpressing strains of these genes were constructed in a haploid derivative of this strain to determine the importance of these genes in growth and fermentation at low temperature. In general, the deletion and overexpression of these genes did affect fermentation performance at low temperature. Most of the mutants were unable to complete fermentation, while overexpression of CSF1, HSP104, and TIR2 decreased the lag phase, increased the fermentation rate, and reached higher populations than that of the control strain. Another set of overexpressing strains were constructed by integrating copies of these genes in the delta regions of the commercial wine strain QA23. These new stable overexpressing strains again showed improved fermentation performance at low temperature, especially during the lag and exponential phases. Our results demonstrate the convenience of carrying out functional analysis in commercial strains and in an experimental set-up close to industrial conditions.

  14. Kinetic model of continuous ethanol fermentation in closed-circulating process with pervaporation membrane bioreactor by Saccharomyces cerevisiae.

    Science.gov (United States)

    Fan, Senqing; Chen, Shiping; Tang, Xiaoyu; Xiao, Zeyi; Deng, Qing; Yao, Peina; Sun, Zhaopeng; Zhang, Yan; Chen, Chunyan

    2015-02-01

    Unstructured kinetic models were proposed to describe the principal kinetics involved in ethanol fermentation in a continuous and closed-circulating fermentation (CCCF) process with a pervaporation membrane bioreactor. After ethanol was removed in situ from the broth by the membrane pervaporation, the secondary metabolites accumulated in the broth became the inhibitors to cell growth. The cell death rate related to the deterioration of the culture environment was described as a function of the cell concentration and fermentation time. In CCCF process, 609.8 g L(-1) and 750.1 g L(-1) of ethanol production were obtained in the first run and second run, respectively. The modified Gompertz model, correlating the ethanol production with the fermentation period, could be used to describe the ethanol production during CCCF process. The fitting results by the models showed good agreement with the experimental data. These models could be employed for the CCCF process technology development for ethanol fermentation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Selected non-Saccharomyces wine yeasts in controlled multistarter fermentations with Saccharomyces cerevisiae on alcoholic fermentation behaviour and wine aroma of cherry wines.

    Science.gov (United States)

    Sun, Shu Yang; Gong, Han Sheng; Jiang, Xiao Man; Zhao, Yu Ping

    2014-12-01

    This study examined the effect of mixed fermentation of non-Saccharomyces (Torulaspora delbrueckii ZYMAFLORE Alpha(TD n. Sacch) and Metschnikowia pulcherrima JS22) and Saccharomyces cerevisiae yeasts (D254 and EC1118) on the production of cherry wines, in comparison with commonly used mono-culture. Results obtained during AF demonstrated that negligible inhibitory effect was observed in S. cerevisiae/Alpha pair, whereas a strong antagonistic effect was detected between MJS22 and S. cerevisiae strain, resulting in an early death of MJS22. For volatile components determined, S. cerevisiae/MJS22 couple was found to significantly boost the production of most detected compounds, more particularly in higher alcohols, esters, acids and terpenes; while the characteristic of S. cerevisiae/Alpha pair is an increase in fruity esters, higher alcohols and decrease in acid production. Sensory evaluation revealed that S. cerevisiae/MJS22 pair reinforced sweet, green and fatty notes to the cherry wines, and S. cerevisiae/Alpha trial enhanced the fruity odour and reduced green note.

  16. Ethanol fermentation of a diluted molasses medium by Saccharomyces cerevisiae immobilized on chrysotile

    Directory of Open Access Journals (Sweden)

    Monte Alegre Ranulfo

    2003-01-01

    Full Text Available In this work, the catalytic role of chrysotile support on the acceleration of alcoholic fermentation under non-aseptic conditions by Saccharomyces cerevisiae was investigated. The fermentation medium employed consisted only of diluted sugar-cane molasses. In the batch fermentations process with immobilized yeasts, the initial rate of CO2 production increased roughly 27 % during the first 30 minutes, compared to systems containing no chrysotile. A study of continuous alcoholic fermentation with chrysotile in the reactor bed showed a higher ethanol production rate at the different dilution rates investigated compared to similar fermentations without chrysotile.

  17. Volatile compounds formation in alcoholic fermentation from grapes collected at 2 maturation stages: influence of nitrogen compounds and grape variety.

    Science.gov (United States)

    Martínez-Gil, Ana M; Garde-Cerdán, Teresa; Lorenzo, Cándida; Lara, José Félix; Pardo, Francisco; Salinas, M Rosario

    2012-01-01

    The aim of this work was to study the influence of nitrogen compounds on the formation of volatile compounds during the alcoholic fermentation carried out with 4 nonaromatic grape varieties collected at 2 different maturation stages. To do this, Monastrell, Merlot, Syrah, and Petit Verdot grapes were collected 1 wk before harvest and at harvest. Then, the musts were inoculated with the same Saccharomyces cerevisiae yeast strain and were fermented in the same winemaking conditions. Amino acids that showed the highest and the lowest concentration in the must were the same, regardless of the grape variety and maturation stage. Moreover, the consumption of amino acids during the fermentation increased with their concentration in the must. The formation of volatile compounds was not nitrogen composition dependent. However, the concentration of amino acids in the must from grapes collected 1 wk before harvest can be used as a parameter to estimate the concentration of esters in wines from grapes collected at harvest and therefore to have more information to know the grape oenological capacity. Application of principal components analysis (PCA) confirmed the possibility to estimate the concentration of esters in the wines with the concentration of nitrogen compounds in the must.

  18. The usefulness of intermediate products of plum processing for alcoholic fermentation and chemical composition of the obtained distillates.

    Science.gov (United States)

    Balcerek, Maria; Pielech-Przybylska, Katarzyna; Patelski, Piotr; Sapińska, Ewelina; Księżopolska, Mirosława

    2013-05-01

    In this study, an evaluation of intermediate products of plum processing as potential raw materials for distillates production was performed. Effects of composition of mashes on ethanol yield, chemical composition and taste, and flavor of the obtained spirits were determined. The obtained results showed that spontaneous fermentations of the tested products of plum processing with native microflora of raisins resulted in lower ethanol yields, compared to the ones fermented with wine yeast Saccharomyces bayanus. The supplementation of mashes with 120 g/L of sucrose caused an increase in ethanol contents from 6.2 ± 0.2 ÷ 6.5 ± 0.2% v/v in reference mashes (without sucrose addition, fermented with S. bayanus) to ca. 10.3 ± 0.3% v/v, where its highest yields amounted to 94.7 ± 2.9 ÷ 95.6 ± 2.9% of theoretical capacity, without negative changes in raw material originality of distillates. The concentrations of volatile compounds in the obtained distillates exceeding 2000 mg/L alcohol 100% v/v and low content of methanol and hydrocyanic acid, as well as their good taste and aroma make the examined products of plum processing be very attractive raw materials for the plum distillates production.

  19. A Simple Visual Ethanol Biosensor Based on Alcohol Oxidase Immobilized onto Polyaniline Film for Halal Verification of Fermented Beverage Samples

    Science.gov (United States)

    Kuswandi, Bambang; Irmawati, Titi; Hidayat, Moch Amrun; Jayus; Ahmad, Musa

    2014-01-01

    A simple visual ethanol biosensor based on alcohol oxidase (AOX) immobilised onto polyaniline (PANI) film for halal verification of fermented beverage samples is described. This biosensor responds to ethanol via a colour change from green to blue, due to the enzymatic reaction of ethanol that produces acetaldehyde and hydrogen peroxide, when the latter oxidizes the PANI film. The procedure to obtain this biosensor consists of the immobilization of AOX onto PANI film by adsorption. For the immobilisation, an AOX solution is deposited on the PANI film and left at room temperature until dried (30 min). The biosensor was constructed as a dip stick for visual and simple use. The colour changes of the films have been scanned and analysed using image analysis software (i.e., ImageJ) to study the characteristics of the biosensor's response toward ethanol. The biosensor has a linear response in an ethanol concentration range of 0.01%–0.8%, with a correlation coefficient (r) of 0.996. The limit detection of the biosensor was 0.001%, with reproducibility (RSD) of 1.6% and a life time up to seven weeks when stored at 4 °C. The biosensor provides accurate results for ethanol determination in fermented drinks and was in good agreement with the standard method (gas chromatography) results. Thus, the biosensor could be used as a simple visual method for ethanol determination in fermented beverage samples that can be useful for Muslim community for halal verification. PMID:24473284

  20. Ethanol-induced leakage in Saccharomyces cerevisiae: kinetics and relationship to yeast ethanol tolerance and alcohol fermentation productivity

    Energy Technology Data Exchange (ETDEWEB)

    Salgueiro, S.P.; Sa-Correia, I.; Novais, J.M.

    1988-04-01

    Ethanol stimulated the leakage of amino acids and 260-nm-light-absorbing compounds from cells of Saccharomyces cerevisiae. The efflux followed first-order kinetics over an initial period. In the presence of lethal concentrations of ethanol, the efflux rates at 30 and 36/sup 0/C were an exponential function of ethanol concentration. At 36/sup 0/C, as compared with the corresponding values at 30/sup 0/C, the efflux rates were higher and the minimal concentration of ethanol was lower. The exponential constants for the enhancement of the rate of leakage had similar values at 30 or 36/sup 0/C and were of the same order of magnitude as the corresponding exponential constants for ethanol-induced death. Under isothermic conditions (30/sup 0/C) and up to 22% (vol/vol) ethanol, the resistance to ethanol-induced leakage of 260-nm-light-absorbing compounds was found to be closely related with the ethanol tolerance of three strains of yeasts, Kluyveromyces marxianus, Saccharomyces cerevisiae, and Saccharomyces bayanus. The resistance to ethanol-induced leakage indicates the possible adoption of the present method for the rapid screening of ethanol-tolerant strains. The addition to a fermentation medium of the intracellular material obtained by ethanol permeabilization of yeast cells led to improvements in alcohol fermentation by S. cerevisiae and S. bayanus. The action of the intracellular material, by improving yeast ethanol tolerance, and the advantages of partially recycling the fermented medium after distillation were discussed.

  1. Development of strains of the thermotolerant yeast Hansenula polymorpha capable of alcoholic fermentation of starch and xylan.

    Science.gov (United States)

    Voronovsky, Andriy Y; Rohulya, Olha V; Abbas, Charles A; Sibirny, Andriy A

    2009-01-01

    The thermotolerant yeast Hansenula polymorpha ferments glucose and xylose to ethanol at high temperatures. However, H. polymorpha cannot utilize starchy materials or xylans. Heterologous amylolytic and xylanolytic enzymes have to be expressed in this yeast to provide for utilization and growth on starch and xylan. Genes SWA2 and GAM1 from the yeast Schwanniomyces occidentalis, encoding alpha-amylase and glucoamylase, respectively, were expressed in H. polymorpha. The expression was achieved by integration of the SWA2 and GAM1 genes under the strong constitutive promoter of the H. polymorpha glyceraldehyde-3-phosphate dehydrogenase gene (HpGAP) into H. polymorpha genome. Resulting transformants acquired the ability to grow on a minimal medium containing soluble starch as a sole carbon source. Ethanol production at high-temperature fermentation from starch by the recombinant strains was up to 10 g/L. The XYN2 gene encoding endoxylanase of the fungus Trichoderma reseei was expressed in H. polymorpha. Co-expression of xlnD gene coding for beta-xylosidase of the fungus Aspergillus niger and the XYN2 gene in H. polymorpha was achieved by integration of these genes under control of the HpGAP promoter. Resulting transformants were capable of growth and alcoholic fermentation on a minimal medium supplemented with birchwood xylan as a sole carbon source at 48 degrees C.

  2. In vivo regulation of alcohol dehydrogenase and lactate dehydrogenase in Rhizopus oryzae to improve L-lactic acid fermentation.

    Science.gov (United States)

    Thitiprasert, Sitanan; Sooksai, Sarintip; Thongchul, Nuttha

    2011-08-01

    Rhizopus oryzae is becoming more important due to its ability to produce an optically pure L: -lactic acid. However, fermentation by Rhizopus usually suffers from low yield because of production of ethanol as a byproduct. Limiting ethanol production in living immobilized R. oryzae by inhibition of alcohol dehydrogenase (ADH) was observed in shake flask fermentation. The effects of ADH inhibitors added into the medium on the regulation of ADH and lactate dehydrogenase (LDH) as well as the production of cell biomass, lactic acid, and ethanol were elucidated. 1,2-diazole and 2,2,2-trifluroethanol were found to be the effective inhibitors used in this study. The highest lactic acid yield of 0.47 g/g glucose was obtained when 0.01 mM 2,2,2-trifluoroethanol was present during the production phase of the pregrown R. oryzae. This represents about 38% increase in yield as compared with that from the simple glucose fermentation. Fungal metabolism was suppressed when iodoacetic acid, N-ethylmaleimide, 4,4'-dithiodipyridine, or 4-hydroxymercury benzoic acid were present. Dramatic increase in ADH and LDH activities but slight change in product yields might be explained by the inhibitors controlling enzyme activities at the pyruvate branch point. This showed that in living R. oryzae, the inhibitors regulated the flux through the related pathways.

  3. Ruminal fermentation, microbial growth and amino acid flow in single-flow continuous culture fermenters fed a diet containing olive leaves.

    Science.gov (United States)

    Molina-Alcaide, E; Martín-García, A I; Moumen, A; Carro, M D

    2010-04-01

    Six single-flow continuous culture fermenters were used to determine fermentation profile, microbial growth and amino acid (AA) flow promoted by olive leaves supplemented with barley grains and faba beans (OLSUP), and alfalfa hay (AH). Two incubation runs were carried out with three fermenters inoculated with ruminal fluid from wethers and three from goats. The inoculum source did not affect (p = 0.059 to 0.980) any of the parameters. Daily volatile fatty acid (VFA) production and carbohydrate digestibility were greater (p = 0.009 and 0.024, respectively) for AH, therefore the pH values were lower (p = 0.015) than for OLSUP. Acetate was greater (p microbial N flow and efficiency were greater (p = 0.016 and p = 0.041) for diet AH. Individual AA flows were greater (p microbial essential AA proportion was greater for OLSUP (p = 0.015). The results indicate that OLSUP promoted lower bacterial growth and AA flow than AH, which could have been partially due to a limitation of N availability to ruminal microbes.

  4. Dynamic proteomic analysis reveals a switch between central carbon metabolism and alcoholic fermentation in rice filling grains.

    Science.gov (United States)

    Xu, Sheng Bao; Li, Tang; Deng, Zhu Yun; Chong, Kang; Xue, Yongbiao; Wang, Tai

    2008-10-01

    Accumulation of reserve materials in filling grains involves the coordination of different metabolic and cellular processes, and understanding the molecular mechanisms underlying the interconnections remains a major challenge for proteomics. Rice (Oryza sativa) is an excellent model for studying grain filling because of its importance as a staple food and the available genome sequence database. Our observations showed that embryo differentiation and endosperm cellularization in developing rice seeds were completed approximately 6 d after flowering (DAF); thereafter, the immature seeds mainly underwent cell enlargement and reached the size of mature seeds at 12 DAF. Grain filling began at 6 DAF and lasted until 20 DAF. Dynamic proteomic analyses revealed 396 protein spots differentially expressed throughout eight sequential developmental stages from 6 to 20 DAF and determined 345 identities. These proteins were involved in different cellular and metabolic processes with a prominently functional skew toward metabolism (45%) and protein synthesis/destination (20%). Expression analyses of protein groups associated with different functional categories/subcategories showed that substantially up-regulated proteins were involved in starch synthesis and alcoholic fermentation, whereas the down-regulated proteins in the process were involved in central carbon metabolism and most of the other functional categories/subcategories such as cell growth/division, protein synthesis, proteolysis, and signal transduction. The coordinated changes were consistent with the transition from cell growth and differentiation to starch synthesis and clearly indicated that a switch from central carbon metabolism to alcoholic fermentation may be important for starch synthesis and accumulation in the developmental process.

  5. [Determination of sugars, organic acids and alcohols in microbial consortium fermentation broth from cellulose using high performance liquid chromatography].

    Science.gov (United States)

    Jiang, Yan; Fan, Guifang; Du, Ran; Li, Peipei; Jiang, Li

    2015-08-01

    A high performance liquid chromatographic method was established for the determination of metabolites (sugars, organic acids and alcohols) in microbial consortium fermentation broth from cellulose. Sulfate was first added in the samples to precipitate calcium ions in microbial consortium culture medium and lower the pH of the solution to avoid the dissociation of organic acids, then the filtrates were effectively separated using high performance liquid chromatography. Cellobiose, glucose, ethanol, butanol, glycerol, acetic acid and butyric acid were quantitatively analyzed. The detection limits were in the range of 0.10-2.00 mg/L. The linear correlation coefficients were greater than 0.999 6 in the range of 0.020 to 1.000 g/L. The recoveries were in the range of 85.41%-115.60% with the relative standard deviations of 0.22% -4.62% (n = 6). This method is accurate for the quantitative analysis of the alcohols, organic acids and saccharides in microbial consortium fermentation broth from cellulose.

  6. Continuous acetone-butanol-ethanol fermentation using SO2-ethanol-water spent liquor from spruce.

    Science.gov (United States)

    Survase, Shrikant A; Sklavounos, Evangelos; Jurgens, German; van Heiningen, Adriaan; Granström, Tom

    2011-12-01

    SO2-ethanol-water (SEW) spent liquor from spruce chips was successfully used for batch and continuous production of acetone, butanol and ethanol (ABE). Initially, batch experiments were performed using spent liquor to check the suitability for production of ABE. Maximum concentration of total ABE was found to be 8.79 g/l using 4-fold diluted SEW liquor supplemented with 35 g/l of glucose. The effect of dilution rate on solvent production, productivity and yield was studied in column reactor consisting of immobilized Clostridium acetobutylicum DSM 792 on wood pulp. Total solvent concentration of 12 g/l was obtained at a dilution rate of 0.21 h(-1). The maximum solvent productivity (4.86 g/l h) with yield of 0.27 g/g was obtained at dilution rate of 0.64 h(-1). Further, to increase the solvent yield, the unutilized sugars were subjected to batch fermentation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Cane molasses fermentation for continuous ethanol production in an immobilized cells reactor by Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Ghorbani, Farshid; Younesi, Habibollah; Esmaeili Sari, Abbas [Department of Environmental Science, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University, Noor, P.O. Box: 64414-356 (Iran); Najafpour, Ghasem [Department of Chemical Engineering, Faculty of Engineering, Noshirvani University of Technology, Babol (Iran)

    2011-02-15

    Sodium-alginate immobilized yeast was employed to produce ethanol continuously using cane molasses as a carbon source in an immobilized cell reactor (ICR). The immobilization of Saccharomyces cerevisiae was performed by entrapment of the cell cultured media harvested at exponential growth phase (16 h) with 3% sodium alginate. During the initial stage of operation, the ICR was loaded with fresh beads of mean diameter of 5.01 mm. The ethanol production was affected by the concentration of the cane molasses (50, 100 and 150 g/l), dilution rates (0.064, 0.096, 0.144 and 0.192 h{sup -1}) and hydraulic retention time (5.21, 6.94, 10.42 and 15.63 h) of the media. The pH of the feed medium was set at 4.5 and the fermentation was carried out at an ambient temperature. The maximum ethanol production, theoretical yield (Y{sub E/S}), volumetric ethanol productivity (Q{sub P}) and total sugar consumption was 19.15 g/l, 46.23%, 2.39 g l{sup -1} h{sup -1} and 96%, respectively. (author)

  8. Bioconversion of Waste Gases into Biofuel via Fermentation in a Continuous Stirred Tank Bioreactor

    Directory of Open Access Journals (Sweden)

    Najafpour, G.

    2005-01-01

    Full Text Available Biological hydrogen production was carried out in a continuous stirred tank bioreactor. A photosynthetic bacterium, Rhodospirillum rubrum, was used as biocatalyst to oxidize carbon monoxides in the waste gas generated from biomass in a gasification process. The fresh liquid media was supplied for microbial growth which contained sodium acetate as carbon source at initial concentration of 4 gL-1. The optimum media space velocity or the suitable ratio of liquid flow rate to the reactor volume (F/VL was 0.02 h-1. At the steady state condition, the concentration of acetate was independent of the dilution rate and it was approximately 1.5 gL-1. The average cell dry weight in the fermentation broth was at satisfactory concentration, approximately 3.4 gL-1 with dilution rate at 0.55 mL min-1. The maximum value of KLa and CO conversion were about 58 h-1 and 80%, respectively, with agitation speed at 500 rpm and gas flow rate at 14 mL min-1. At this condition, the maximum yield of hydrogen production was 0.82 mmol H2•mmol-1 CO.

  9. Effect of the organic loading rate on biogas composition in continuous fermentative hydrogen production.

    Science.gov (United States)

    Spagni, Alessandro; Casu, Stefania; Farina, Roberto

    2010-10-01

    Some systems did not select for hydrogen-producing microorganisms and an unexpected growth of hydrogenotrophic methanogens was observed, although the reactors were operated under well-defined operating conditions that could result in biohydrogen production. The aim of this study was to evaluate the effect of the organic loading rate (OLR) on the hydrogen and methane composition of the biogas produced in dark fermentative processes. The study was carried out using an upflow anaerobic sludge blanket (UASB) reactor in order to evaluate the OLR effect in systems with sludge retention. During continuous operation, the UASB reactor showed the slow development of methanogenic activity, related to the applied OLR. The results demonstrate that operating an UASB reactor at pH 5.5 is not enough to prevent the acclimation of methanogens to the acidic pH and therefore long-term biohydrogen production cannot be achieved. Moreover, this study demonstrates that OLR also has an effect on the biogas composition, where the higher the OLR the greater the biogas H2 content.

  10. Fermentation to ethanol of pentose-containing spent sulphite liquor

    Energy Technology Data Exchange (ETDEWEB)

    Yu, S.; Wayman, M.; Parekh, S.K.

    1987-06-01

    Ethanolic fermentation of spent sulphite liquor with ordinary bakers' yeast is incomplete because this yeast cannot ferment the pentose sugars in the liquor. This results in poor alcohol yields, and a residual effluent problem. By using the yeast Candida shehatae (R) for fermentation of the spent sulphite liquor from a large Canadian alcohol-producing sulphite pulp and paper mill, pentoses as well as hexoses were fermented nearly completely, alcohol yields were raised by 33%, and sugar removal increased by 46%. Inhibitors were removed prior to fermentation by steam stripping. Major benefits were obtained by careful recycling of this yeast, which was shown to be tolerant both of high sugar concentrations and high alcohol concentrations. When sugar concentrations over 250 g/L (glucose:xylose 70:30) were fermented, ethanol became an inhibitor when its concentration reached 90 g/L. However, when the ethanol was removed by low-temperature vacuum distillation, fermentation continued and resulted in a yield of 0.50 g ethanol/g sugar consumed. Further improvement was achieved by combining enzyme saccharification of sugar oligomers with fermentation. This yeast is able to ferment both hexoses and pentoses simultaneously, efficiently, and rapidly. Present indications are that it is well suited to industrial operations wherever hexoses and pentoses are both to be fermented to ethanol, for example, in wood hydrolysates. (Refs. 6).

  11. Separation technologies for the recovery and dehydration of alcohols from fermentation broths

    Science.gov (United States)

    Multi-column distillation followed by molecular sieve adsorption is currently the standard method for producing fuel grade ethanol from dilute fermentation broths in modern corn-to-ethnol facilities. As the liquid biofuels industry transitions to lignocellulosic feedstocks, expan...

  12. Membrane-based recovery and dehydration of alcohols from fermentation broths - of materials and modules

    Science.gov (United States)

    Distillation combined with molecular sieve dehydration is the current state of the art for fuel grade ethanol production from fermentation broths. As the liquid biofuels industry transitions to lignocellulosic feedstocks, expands the end product portfolio to include other alcoho...

  13. Separation technologies for the recovery and dehydration of alcohols from fermentation broths

    Science.gov (United States)

    Multi-column distillation followed by molecular sieve adsorption is currently the standard method for producing fuel grade ethanol from dilute fermentation broths in modern corn-to-ethnol facilities. As the liquid biofuels industry transitions to lignocellulosic feedstocks, expan...

  14. Increased expression of the yeast multidrug resistance ABC transporter Pdr18 leads to increased ethanol tolerance and ethanol production in high gravity alcoholic fermentation

    Directory of Open Access Journals (Sweden)

    Teixeira Miguel C

    2012-07-01

    Full Text Available Abstract Background The understanding of the molecular basis of yeast tolerance to ethanol may guide the design of rational strategies to increase process performance in industrial alcoholic fermentations. A set of 21 genes encoding multidrug transporters from the ATP-Binding Cassette (ABC Superfamily and Major Facilitator Superfamily (MFS in S. cerevisiae were scrutinized for a role in ethanol stress resistance. Results A yeast multidrug resistance ABC transporter encoded by the PDR18 gene, proposed to play a role in the incorporation of ergosterol in the yeast plasma membrane, was found to confer resistance to growth inhibitory concentrations of ethanol. PDR18 expression was seen to contribute to decreased 3 H-ethanol intracellular concentrations and decreased plasma membrane permeabilization of yeast cells challenged with inhibitory ethanol concentrations. Given the increased tolerance to ethanol of cells expressing PDR18, the final concentration of ethanol produced during high gravity alcoholic fermentation by yeast cells devoid of PDR18 was lower than the final ethanol concentration produced by the corresponding parental strain. Moreover, an engineered yeast strain in which the PDR18 promoter was replaced in the genome by the stronger PDR5 promoter, leading to increased PDR18 mRNA levels during alcoholic fermentation, was able to attain a 6 % higher ethanol concentration and a 17 % higher ethanol production yield than the parental strain. The improved fermentative performance of yeast cells over-expressing PDR18 was found to correlate with their increased ethanol tolerance and ability to restrain plasma membrane permeabilization induced throughout high gravity fermentation. Conclusions PDR18 gene over-expression increases yeast ethanol tolerance and fermentation performance leading to the production of highly inhibitory concentrations of ethanol. PDR18 overexpression in industrial yeast strains appears to be a promising approach to

  15. Fermentation of wood-derived acid hydrolysates in a batch bioreactor and in a continuous dynamic immobilized cell bioreactor by Pichia stipitis R

    Energy Technology Data Exchange (ETDEWEB)

    Parekh, S.R.; Parekh, R.S.; Wayman, M.

    1987-06-01

    Ethanolic fermentation of sugar solutions obtained on acid prehydrolysis of aspen and pine woods and from those present in spent sulphite liquor (SSL) were investigated in batch culture and in a continuous dynamic immobilized cell (CDIC) fermenter. The inhibitory effect of acetic acid on the fermentation of such liquors was overcome by steam-stripping. Major benefits were obtained when Pichia stipitis R was employed in fermenting and removing sugar from SSL compared to Saccharomyces cerevisiae. Ethanol yields were 38% higher along with 40% more sugar removal from softwood SSL. S. cerevisiae was not able to ferment hardwood SSL effectively. Using immobilized cells of P. stipitis R in a CDIC bioreactor, we found that softwood SSL could be fermented in seven hours with 90% xylose fermentation, while hemicellulose hydrolysates were fermented in four to five hours, with an average volumetric ethanol productivity of about 2.6 g/l/h. The merits of using P. stipitis R for efficient and rapid fermentation of xylose-rich hydrolysates, and the possible application of the CDIC bioreactor to continuous ethanolic fermentations are discussed. (Refs. 28).

  16. 甘蔗糖蜜酒精无酸发酵应用现状与展望%The Application Status and Prospect of Acid-Free Fermentation of Molasses for Alcohol

    Institute of Scientific and Technical Information of China (English)

    尚红岩

    2014-01-01

    Acid-free fermentation process can overcome the damage of sulfuric acid to equipment and environment. It has been successfully used in some molasses alcohol plants in the past 10 years. Acid-free fermentation encounters problem of uncontrollable bacterial infection due to lower molasses purity and therefore molasses alcohol plants have to give up acid-free fermentation process. Increasing content of ash and colloid in molasses could inhibit the growth and breeding of yeast, and yeast is unable to obtain the growth advantage to bacteria, resulting in acid-free fermentation process unable to continue application. In acid-free or weak-acid conditions, only removing ash and colloid in molasses as much as possible can we fundamentally solve the problem of bacteria infection in free-acid fermentation.%无酸发酵工艺克服了添加硫酸对设备、环境的危害,十多年来在糖蜜酒精行业多家酒精厂成功应用。随着糖蜜纯度变低,无酸发酵遭遇到细菌感染无法控制等问题,甘蔗糖蜜酒精厂陆续放弃无酸发酵工艺。糖蜜中含量不断增多的灰分、胶体等物质抑制酵母生长繁殖,酵母对细菌无法取得生长优势,导致无酸发酵工艺无法继续应用。在无酸或微酸条件下,尽可能多地排除糖蜜中灰分和胶体,才能从根本上解决无酸发酵染菌问题。

  17. Use of continuous lactose fermentation for ethanol production by Kluveromyces marxianus for verification and extension of a biochemically structured model

    DEFF Research Database (Denmark)

    Sansonetti, S.; Hobley, Timothy John; Curcio, S.

    2013-01-01

    A biochemically structured model has been developed to describe the continuous fermentation of lactose to ethanol by Kluveromyces marxianus and allowed metabolic coefficients to be determined. Anaerobic lactose-limited chemostat fermentations at different dilution rates (0.02 – 0.35 h-1) were per...... agreed very closely with those determined by regressions of the experimental data. The model developed provides a solid basis for the rational design of optimised fermentation of cheese whey....

  18. Monitoring of Saccharomyces cerevisiae, Hanseniaspora uvarum, and Starmerella bacillaris (synonym Candida zemplinina) populations during alcoholic fermentation by fluorescence in situ hybridization.

    Science.gov (United States)

    Wang, Chunxiao; Esteve-Zarzoso, Braulio; Mas, Albert

    2014-11-17

    Various molecular approaches have been applied as culture-independent techniques to monitor wine fermentations over the last decade. Among them, those based on RNA detection have been widely used for yeast cell detection, assuming that RNA only exists in live cells. Fluorescence in situ hybridization (FISH) targeting intracellular rRNA is considered a promising technique for the investigation of wine ecology. For the present study, we applied the FISH technique in combination with epifluorescence microscopy and flow cytometry to directly quantify populations of Saccharomyces cerevisiae, Hanseniaspora uvarum, and Starmerella bacillaris during alcoholic fermentations. A new specific probe that hybridizes with eight species of Hanseniaspora genus and a second probe specific for Starm. bacillaris were designed, and the conditions for their application to pure cultures, mixed cultures, and wine samples were optimized. Single and mixed fermentations were performed with natural, concentrated must at two different temperatures, 15 °C and 25 °C. The population dynamics revealed that the Sacch. cerevisiae population increased to 10(7)-10(8)cells/ml during all fermentations, whereas H. uvarum and Starm. bacillaris tended to increase in single fermentations but remained at levels similar to their inoculations at 10(6)cells/ml in mixed fermentations. Temperature mainly affected the fermentation duration (slower at the lower temperature) but did not affect the population sizes of the different species. The use of these probes in natural wine fermentations has been validated.

  19. Effect of low pH start-up on continuous mixed-culture lactic acid fermentation of dairy effluent.

    Science.gov (United States)

    Choi, Gyucheol; Kim, Jaai; Lee, Changsoo

    2016-12-01

    Mixed-culture fermentation that does not require an energy-intensive sterilization process is a viable approach for the economically feasible production of lactic acid (LA) due to the potential use of organic waste as feedstock. This study investigated mixed-culture LA fermentation of whey, a high-strength organic wastewater, in continuous mode. Variations in the hydraulic retention time (HRT) from 120 to 8 h under different pH regimes in two thermophilic reactors (55 °C) were compared for their fermentation performance. One reactor was maintained at a low pH (pH 3.0) during operation at HRTs of 120 to 24 h and then adjusted to pH 5.5 in the later phases of fermentation at HRTs of 24 to 8 h (R1), while the second reactor was maintained at pH 5.5 throughout the experiment (R2). Although the LA production in R1 was negligible at low pH, it increased dramatically after the pH was raised to 5.5 and exceeded that in R2 when stabilized at HRTs of 8 and 12 h. The maximum yield (0.62 g LA/g substrate fed as the chemical oxygen demand (COD) equivalent), the production rate (11.5 g/L day), and the selectivity (95 %) of LA were all determined at a 12-h HRT in R1. Additionally, molecular and statistical analyses revealed that changes in the HRT and the pH significantly affected the bacterial community structure and thus the fermentation characteristics of the experimental reactors. Bacillus coagulans was likely the predominant LA producer in both reactors. The overall results suggest that low pH start-up has a positive effect on yield and selectivity in mixed-culture LA fermentation.

  20. Mathematical modeling of continuous ethanol fermentation in a membrane bioreactor by pervaporation compared to conventional system: Genetic algorithm.

    Science.gov (United States)

    Esfahanian, Mehri; Shokuhi Rad, Ali; Khoshhal, Saeed; Najafpour, Ghasem; Asghari, Behnam

    2016-07-01

    In this paper, genetic algorithm was used to investigate mathematical modeling of ethanol fermentation in a continuous conventional bioreactor (CCBR) and a continuous membrane bioreactor (CMBR) by ethanol permselective polydimethylsiloxane (PDMS) membrane. A lab scale CMBR with medium glucose concentration of 100gL(-1) and Saccharomyces cerevisiae microorganism was designed and fabricated. At dilution rate of 0.14h(-1), maximum specific cell growth rate and productivity of 0.27h(-1) and 6.49gL(-1)h(-1) were respectively found in CMBR. However, at very high dilution rate, the performance of CMBR was quite similar to conventional fermentation on account of insufficient incubation time. In both systems, genetic algorithm modeling of cell growth, ethanol production and glucose concentration were conducted based on Monod and Moser kinetic models during each retention time at unsteady condition. The results showed that Moser kinetic model was more satisfactory and desirable than Monod model.

  1. Comparative technoeconomic analysis of a softwood ethanol process featuring posthydrolysis sugars concentration operations and continuous fermentation with cell recycle.

    Science.gov (United States)

    Schneiderman, Steven J; Gurram, Raghu N; Menkhaus, Todd J; Gilcrease, Patrick C

    2015-01-01

    Economical production of second generation ethanol from Ponderosa pine is of interest due to widespread mountain pine beetle infestation in the western United States and Canada. The conversion process is limited by low glucose and high inhibitor concentrations resulting from conventional low-solids dilute acid pretreatment and enzymatic hydrolysis. Inhibited fermentations require larger fermentors (due to reduced volumetric productivity) and low sugars lead to low ethanol titers, increasing distillation costs. In this work, multiple effect evaporation (MEE) and nanofiltration (NF) were evaluated to concentrate the hydrolysate from 30 g/l to 100, 150, or 200 g/l glucose. To ferment this high gravity, inhibitor containing stream, traditional batch fermentation was compared with continuous stirred tank fermentation (CSTF) and continuous fermentation with cell recycle (CSTF-CR). Equivalent annual operating cost (EAOC = amortized capital + yearly operating expenses) was used to compare these potential improvements for a local-scale 5 MGY ethanol production facility. Hydrolysate concentration via evaporation increased EAOC over the base process due to the capital and energy intensive nature of evaporating a very dilute sugar stream; however, concentration via NF decreased EAOC for several of the cases (by 2 to 15%). NF concentration to 100 g/l glucose with a CSTF-CR was the most economical option, reducing EAOC by $0.15 per gallon ethanol produced. Sensitivity analyses on NF options showed that EAOC improvement over the base case could still be realized for even higher solids removal requirements (up to two times higher centrifuge requirement for the best case) or decreased NF performance.

  2. Exploring Continuity of Care in Patients with Alcohol Use Disorders Using Time-Variant Measures

    NARCIS (Netherlands)

    S.C. de Vries (Sjoerd); A.I. Wierdsma (André)

    2009-01-01

    textabstractBackground/Aims: We used time-variant measures of continuity of care to study fluctuations in long-term treatment use by patients with alcohol-related disorders. Methods: Data on service use were extracted from the Psychiatric Case Register for the Rotterdam Region, The Netherlands. Cont

  3. Multi-stage Continuous Culture Fermentation of Glucose-Xylose Mixtures to Fuel Ethanol using Genetically Engineered Saccharomyces cerevisiae 424A

    Science.gov (United States)

    Multi-stage continuous (chemostat) culture fermentation (MCCF) with variable fermentor volumes was carried out to study utilizing glucose and xylose for ethanol production by means of mixed sugar fermentation (MSF). Variable fermentor volumes were used to enable enhanced sugar u...

  4. Multi-stage Continuous Culture Fermentation of Glucose-Xylose Mixtures to Fuel Ethanol using Genetically Engineered Saccharomyces cerevisiae 424A

    Science.gov (United States)

    Multi-stage continuous (chemostat) culture fermentation (MCCF) with variable fermentor volumes was carried out to study utilizing glucose and xylose for ethanol production by means of mixed sugar fermentation (MSF). Variable fermentor volumes were used to enable enhanced sugar u...

  5. Real-time DNP NMR observations of acetic acid uptake, intracellular acidification, and of consequences for glycolysis and alcoholic fermentation in yeast.

    Science.gov (United States)

    Jensen, Pernille R; Karlsson, Magnus; Lerche, Mathilde H; Meier, Sebastian

    2013-09-27

    Uptake and upshot in vivo: Straightforward methods that permit the real-time observation of organic acid influx, intracellular acidification, and concomitant effects on cellular-reaction networks are crucial for improved bioprocess monitoring and control. Herein, dynamic nuclear polarization (DNP) NMR is used to observe acetate influx, ensuing intracellular acidification and the metabolic consequences on alcoholic fermentation and glycolysis in living cells.

  6. 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)

  7. 石榴果醋酒精发酵工艺的研究%Research on Alcohol Fermentation Technology of Pomegranate Fruit Vinegar

    Institute of Scientific and Technical Information of China (English)

    赵文亚; 张立华; 孙中贯

    2015-01-01

    以石榴为原料,研究石榴果醋的生产,对石榴果醋制作过程中酒精发酵进行了研究。通过单因素和正交试验,得出酒精发酵的最佳工艺条件,即酵母接种量为0.10%、发酵温度为28℃、初始糖度为16%。%Pomegranate was used as raw material to produce the fruit wine. The main processing technology of alcohol fermentation were studied. By single factor experiment and the orthogonal experiment , the optimum alcoholic fermentation conditions were obtained. ,for inoculum of yeast 0.10%, fermentation temperature28℃, sugar content 16%.

  8. Melatonin and derived l-tryptophan metabolites produced during alcoholic fermentation by different wine yeast strains.

    Science.gov (United States)

    Fernández-Cruz, E; Álvarez-Fernández, M A; Valero, E; Troncoso, A M; García-Parrilla, M C

    2017-02-15

    Melatonin is a neurohormone involved in the regulation of circadian rhythms in humans. Evidence has recently been found of its occurrence in wines and its role in the winemaking process. The yeast Saccharomyces cerevisiae is consequently thought to be important in Melatonin synthesis, but limited data and reference texts are available on this synthetic pathway. This paper aims to elucidate whether the synthetic pathway of Melatonin in Saccharomyces and non-Saccharomyces strains involves these intermediates. To this end, seven commercial strains comprising Saccharomyces cerevisiae (Red Fruit, ES488, Lalvin QA23, Uvaferm BC, and Lalvin ICV GRE) and non-Saccharomyces (Torulaspora delbrueckii and Metschnikowia pulcherrima) were monitored, under controlled fermentation conditions, in synthetic must, for seven days. Samples were analysed using a UHPLC-HRMS system (Qexactive). Five out of the seven strains formed Melatonin during the fermentation process: three S. cerevisiae strains and the two non-Saccharomyces. Additionally, other compounds derived from l-tryptophan occurred during fermentation.

  9. Fermentative hydrogen production from beet sugar factory wastewater treatment in a continuous stirred tank reactor using anaerobic mixed consortia

    Institute of Scientific and Technical Information of China (English)

    Gefu ZHU; Chaoxiang LIU; Jianzheng LI; Nanqi REN; Lin LIU; Xu HUANG

    2013-01-01

    A low pH, ethanol-type fermentation process was evaluated for wastewater treatment and bio-hydrogen production from acidic beet sugar factory wastewater in a continuous stirred tank reactor (CSTR) with an effective volume of 9.6 L by anaerobic mixed cultures in this present study. After inoculating with aerobic activated sludge and operating at organic loading rate (OLR) of 12 kgCOD·m-3·d-1, HRT of 8h, and temperature of 35℃ for 28 days, the CSTR achieved stable ethanol-type fermentation. When OLR was further increased to 18 kgCOD·m-3·d-1, on the 53rd day, ethanol-type fermentation dominant microflora was enhanced. The liquid fermentation products, including volatile fatty acids (VFAs) and ethanol, stabilized at 1493mg·L-1 in the bioreactor. Effluent pH, oxidation-reduction potential (ORP), and alkalinity ranged at 4.1-4.5, -250-(-290) mV, and 230-260mgCaCO3·L-1. The specific hydrogen production rate of anaerobic activated sludge was 0.1 L'gMLVSS-1· d-1 and the COD removal efficiency was 45%. The experimental results showed that the CSTR system had good operation stability and microbial activity, which led to high substrate conversion rate and hydrogen production ability.

  10. High-Gravity Brewing: Effects of Nutrition on Yeast Composition, Fermentative Ability, and Alcohol Production

    OpenAIRE

    Casey, Gregory P.; Magnus, Carol A.; Ingledew, W M

    1984-01-01

    A number of economic and product quality advantages exist in brewing when high-gravity worts of 16 to 18% dissolved solids are fermented. Above this level, production problems such as slow or stuck fermentations and poor yeast viability occur. Ethanol toxicity has been cited as the main cause, as brewers' yeasts are reported to tolerate only 7 to 9% (vol/vol) ethanol. The inhibitory effect of high osmotic pressure has also been implicated. In this report, it is demonstrated that the factor li...

  11. Degradation of Aflatoxin B1 during the Fermentation of Alcoholic Beverages

    OpenAIRE

    Naoki Mochizuki; Yasushi Nagatomi; Atsuo Uyama; Tomonori Inoue

    2013-01-01

    Aflatoxin B1 (AFB1) is a contaminant of grain and fruit and has one of the highest levels of carcinogenicity of any natural toxin. AFB1 and the fungi that produce it can also contaminate the raw materials used for beer and wine manufacture, such as corn and grapes. Therefore, brewers must ensure strict monitoring to reduce the risk of contamination. In this study, the fate of AFB1 during the fermentation process was investigated using laboratory-scale bottom and top beer fermentation and wine...

  12. 液化方式对小米醋酒精发酵阶段的影响%Effect of Liquefaction on Alcohol Fermentation Stage of Millet Vinegar

    Institute of Scientific and Technical Information of China (English)

    徐清萍; 尧俊英

    2014-01-01

    The effect of liquefaction on alcohol fermentation stage of millet vinegar is studied in this pa-per.The alcohol fermentation rate by using enzymatic liquefaction and saccharification methods is higher than that by Daqu method.The alcohol content of pulverized millet is higher than that of steamed millet.The optimal conditions for alcohol fermentation stage of millet vinegar are determined by orthogonal experiments,which are as follows:heated to 65 ℃,keeping warm for 15 s and thermal liquefaction for 30 min,the alcohol fermentation rate is 77.96%.The ideal fermentation effect can be reached through the method of short-time heating insulation and liquefaction,and the production cost is decreased compared with traditional technology.%主要研究液化方式对小米醋酒精发酵阶段的影响。通过对比试验表明,采用酶法液化糖化后酒精发酵,酒精发酵率要高于采用加入大曲进行发酵的方式。原料采用粉碎后生料发酵酒度高于蒸煮法。采用正交试验,确定热处理温度和时间、液化温度和时间的最佳条件,即加热至65℃保温15 s,65℃保温液化30 min,酒精发酵率达到80.14%。与传统工艺相比,通过采用短时热处理和液化可达到较理想的发酵效果,同时降低能耗。

  13. Production of D-lactic acid in a continuous membrane integrated fermentation reactor by genetically modified Saccharomyces cerevisiae: enhancement in D-lactic acid carbon yield.

    Science.gov (United States)

    Mimitsuka, Takashi; Sawai, Kenji; Kobayashi, Koji; Tsukada, Takeshi; Takeuchi, Norihiro; Yamada, Katsushige; Ogino, Hiroyasu; Yonehara, Tetsu

    2015-01-01

    Poly d-lactic acid is an important polymer because it improves the thermostability of poly l-lactic acid by stereo complex formation. To demonstrate potency of continuous fermentation using a membrane-integrated fermentation reactor (MFR) system, continuous fermentation using genetically modified Saccharomyces cerevisiae which produces d-lactic acid was performed at the low pH and microaerobic conditions. d-Lactic acid continuous fermentation using the MFR system by genetically modified yeast increased production rate by 11-fold compared with batch fermentation. In addition, the carbon yield of d-lactic acid in continuous fermentation was improved to 74.6 ± 2.3% compared to 39.0 ± 1.7% with batch fermentation. This dramatic improvement in carbon yield could not be explained by a reduction in carbon consumption to form cells compared to batch fermentation. Further detailed analysis at batch fermentation revealed that the carbon yield increased to 76.8% at late stationary phase. S. cerevisiae, which exhibits the Crabtree-positive effect, demonstrated significant changes in metabolic activities at low sugar concentrations (Rossignol et al., Yeast, 20, 1369-1385, 2003). Moreover, lactate-producing S. cerevisiae requires ATP supplied not only from the glycolytic pathway but also from the TCA cycle (van Maris et al., Appl. Environ. Microbiol., 70, 2898-2905, 2004). Our finding was revealed that continuous fermentation, which can maintain the conditions of both a low sugar concentration and air supply, results in Crabtree-positive and lactate-producing S. cerevisiae for suitable conditions of d-lactic acid production with respect to redox balance and ATP generation because of releasing the yeast from the Crabtree effect.

  14. Fermentation to ethanol of pentose-containing spent sulfite liquor

    Energy Technology Data Exchange (ETDEWEB)

    Yu, S.; Wayman, M.; Parekh, S.K.

    1987-01-01

    Ethanolic fermentation of spent sulfite liquor with ordinary bakers' yeast is incomplete because of this yeast cannot ferment the pentose sugars in the liquor. This results in poor alcohol yields, and a residual effluent problem. By using the yeast Candida shehatae (R) for fermentation of the spent sulfite liquor from a large Canadian alcohol-producing sulfite pulp and paper mill, pentoses as well as hexoses were fermented nearly completely, alcohol yields were raised by 33%, and sugar removal increased by 46%. Inhibitors were removed prior to fermentation by steam stripping. Major benefits were obtained by careful recycling of this yeast, which was shown to be tolerant both of high sugar concentrations and high alcohol concentrations. When sugar concentrations over 250 g/L (glucose:xylose 70:30) were fermented, ethanol became an inhibitor when its concentration reached over 90 g/L. However, when the ethanol was removed by low-temperature vacuum distillation, fermentation continued and resulted in a yield of 0.50 g ethanol/g sugar consumed. Further improvement was achieved by combining enzyme saccharification of sugar oligomers with fermentation. This yeast is able to ferment both hexoses and pentoses simultaneously, efficiently, and rapidly.

  15. Manufacture of Oat Corn Alcoholic Fermentation Beverages%燕麦谷物酒精发酵饮料的研制

    Institute of Scientific and Technical Information of China (English)

    胡博涵; 刘素纯; 夏延斌; 蒋立文; 李罗明

    2011-01-01

    In this paper fermentation condition of oat com alcoholic fermented beverages using saccharolytic and beer yeast, taking oat as raw material through single factor experiment, orthogonal experiment were studied.The result indicated that the optimum fermentation condition of the oat alcoholic fermented beverages were choose Rhizopus oryzae to ferment the oat at 28℃ after some time and saccharify for 24 h at 42℃, beer yeast addition content was 1.5% (quantity volume of raw material was 1.5%), fermentation temperature was 28℃and fermentation time was 48 hour.Finished product get by blend, bottling and sterilization.The oat fermented beverages with this technology has sweet sour with special oat flavor, decline mellow faint scent.it is a soRT of new-style health and nutrient food.%以燕麦为主要原料,采用糖化菌和啤酒酵母菌对其进行发酵,酿造成低酒精谷物发酵饮料,通过单因素试验和正交试验对发酵条件进行了优化.结果表明,燕麦酒精发酵饮料的最佳发酵条件为:燕麦经根霉Q303,28℃发酵一定时间后,42℃保温糖化24 h,再添加原料量体积的1.5%啤酒酵母,在28℃下发酵48 h.经勾调、均质、分装、杀菌得成品.

  16. NADH-linked aldose reductase: the key to anaerobic alcoholic fermentation of xylose by yeasts

    NARCIS (Netherlands)

    Bruinenberg, P.M.; De Bot, P.H.M.; Van Dijken, J.P.; Scheffers, W.A.

    1984-01-01

    The kinetics and enzymology of o-xylose utilization were studied in aerobic and anaerobic batch cultures of the facultatively fermentative yeasts Candida utilis, Pachysolen tannophilus, and Pichia stipitis. These yeasts did not produce ethanol under aerobic conditions. When shifted to anaerobiosis c

  17. On the influence of thiamine and ammonium ions on alcoholic fermentation

    NARCIS (Netherlands)

    Maesen, Th.J.M.

    1953-01-01

    1. 1. In a glucose-sodium acetate medium of pH 5.6 the fermentation rate of bakers' yeast remains constant at a low level during several hours, while in the presence of ammonium sulphate it gradually increases. The rise is steeper in the presence of thiamine. 2. 2. After the ammonium ions have been

  18. On the influence of thiamine and ammonium ions on alcoholic fermentation

    NARCIS (Netherlands)

    Maesen, Th.J.M.

    1953-01-01

    1. 1. In a glucose-sodium acetate medium of pH 5.6 the fermentation rate of bakers' yeast remains constant at a low level during several hours, while in the presence of ammonium sulphate it gradually increases. The rise is steeper in the presence of thiamine. 2. 2. After the ammonium ions have

  19. On the influence of thiamine and ammonium ions on alcoholic fermentation

    NARCIS (Netherlands)

    Maesen, Th.J.M.

    1953-01-01

    1. 1. In a glucose-sodium acetate medium of pH 5.6 the fermentation rate of bakers' yeast remains constant at a low level during several hours, while in the presence of ammonium sulphate it gradually increases. The rise is steeper in the presence of thiamine. 2. 2. After the ammonium ions have been

  20. Fuel cell-based instrumentation for ethanol determination in alcoholic beverages, fermentations, and biofluids

    Energy Technology Data Exchange (ETDEWEB)

    Parry, K.W.

    1988-01-01

    The main aim of this project was to devise an alternative method for ethanol assay, employing an electrochemical fuel cell sensor. Thus, the early part of this thesis describes the work carried out in the development of a new analytical technique for this purpose. This work resulted in the production of a successful prototype unit which has led to the development of a commercial instrument, vis., the Lion Drinks Alcolmeter (DA-1) available from Lion Laboratories Ltd. The problem of determining the ethanol content of a fermenting liquor at any point during a fermentation process was also broached and a novel technique combining a flow dilution system, dynamic headspace analysis and a fuel cell sensor was developed. This procedure, suitably automated, will enable the ethanolic content of a fermenting beverage to be determined at any stage during a fermentation, the results obtained in this manner being in excellent agreement with those obtained gas chromatographically. Methods of extending the linear working range of a fuel cell-based sampling system are reported in the hope that the encouraging results obtained may initiate further progress in this field. Finally, the sensing system used in this work has also been utilized with an alternative sampling procedure for the determination of ethanol in biological fluids, mainly for clinical and forensic applications. This work has also led to the production of a commercial instrument, viz. the Lion AE-D3 Alcolmeter.

  1. Ultrasound-Assisted Alcohol Fermentation Technology%超声波辅助酒精发酵技术

    Institute of Scientific and Technical Information of China (English)

    王振斌; 刘凤叶; 马海乐; 王林; 张存胜; 闫景坤; 刘加友

    2016-01-01

    In order to promote the development of liquor-making technology, the mechanism of ultrasonic treatment to advance alcohol fermen-tation was explored. Based on the change in yeast amount, residual sugar content in fermenting liquid, ethanol yield, and fermenting liquid vis-cosity before and after ultrasonic treatment, the surface features and water clusters of yeasts before and after ultrasonic treatment were studied by SEM and NMR. The results showed that, in control group, yeast amount and alcohol content reached up to 2.86 × 108 cfu/mL at 42 h and 4.5 g/L at 90 h respectively, fermenting liquid viscosity reduced gradually, the surface of yeast was well-stacked with no defect and no big sag, and 17O half-peak breadth of water clusters was 85.39 Hz;in ultrasonic treatment group, yeast amount reached up to the maximum number of 2.75 × 108 cfu/mL 18 hours in advance, and the consumption rate of reducing sugar and ethanol yield significantly increased, fermenting liquid viscosity was evidently lower than that in the control group, and the surface of yeast was rough and with big sag on the surface, and 17O half-peak breadth of water clusters was 54.32 Hz. This study provided a theoretical evidence for the application of ultrasonic treatment in biological fermentation.%为了促进酿酒工艺的发展,探讨超声波促进酵母酒精发酵的机理,在对超声波处理前后的酵母菌数量、发酵液残糖量、酒精产生量和发酵液黏度研究的基础上,利用扫描电镜和核磁共振技术对超声波处理前后的酵母菌表征和水分子团簇进行了研究。研究结果表明,对照组酵母菌落数和酒精含量分别在42 h和90 h达到最大值2.65×108 cfu/mL和4.5 g/L,发酵液黏度逐渐降低,酵母细胞表面形体饱满,无大的凹陷,发酵末期水分子团17O半峰宽为85.39 Hz。超声组相比对照组菌落总数提前18 h达到最大值2.75×108 cfu/mL,还原糖消耗速率和酒精产生速率显著

  2. Progress in alcoholic fermentation reactor%乙醇发酵反应器的研究进展

    Institute of Scientific and Technical Information of China (English)

    张亚磊; 陈砺; 严宗诚

    2011-01-01

    The application of air lift reactor,immobilized cell reactor and membrane bioreactor in the alcoholic fermentation is mainly reviewed. The merits and shortcomings of each reactor are presented. The possibility of their industrial application is discussed. The prospects of the design for each reactor are also proposed in this paper.%主要介绍了气升式反应器、固定化细胞反应器及膜生物反应器在乙醇发酵生产酒精的应用,讨论了各反应器的优缺点,探讨了其工业化应用的可能性,最后分析了各反应器设计的发展方向.

  3. Identification of reference genes suitable for normalization of RT-qPCR expression data in Saccharomyces cerevisiae during alcoholic fermentation.

    Science.gov (United States)

    Vaudano, Enrico; Noti, Olta; Costantini, Antonella; Garcia-Moruno, Emilia

    2011-08-01

    Expression data from RT-qPCR (reverse transcription quantitative PCR) needs to be normalized to account for experimental variability among samples caused by differential yields of the transcripts in RNA extraction or in the reverse transcription. The most common method is to normalize against one or more reference genes (RG). We have selected RGs suitable for normalization of RT-qPCR raw data in Saccharomyces cerevisiae during alcoholic fermentation. The RGs were evaluated by three different statistical methods. The suitability of the selected RG sets was compared with ACT1, a commonly used non-validated single RG, by normalizing the expression of two target genes. Expression profiles of the target genes revealed the risk of misleading interpretation of expression data due to an unreliable RG.

  4. Investigating unsaturated fat, monensin, or bromoethanesulfonate in continuous cultures retaining ruminal protozoa. I. Fermentation, biohydrogenation, and microbial protein synthesis.

    Science.gov (United States)

    Karnati, S K R; Sylvester, J T; Ribeiro, C V D M; Gilligan, L E; Firkins, J L

    2009-08-01

    Methane is an end product of ruminal fermentation that is energetically wasteful and contributes to global climate change. Bromoethanesulfonate, animal-vegetable fat, and monensin were compared with a control treatment to suppress different functional groups of ruminal prokaryotes in the presence or absence of protozoa to evaluate changes in fermentation, digestibility, and microbial N outflow. Four dual-flow continuous culture fermenter systems were used in 4 periods in a 4 x 4 Latin square design split into 2 subperiods. In subperiod 1, a multistage filter system (50-microm smallest pore size) retained most protozoa. At the start of subperiod 2, conventional filters (300-microm pore size) were substituted to efflux protozoa via filtrate pumps over 3 d; after a further 7 d of adaptation, the fermenters were sampled for 3 d. Treatments were retained during both subperiods. Flow of total N and digestibilities of NDF and OM were 18, 16, and 9% higher, respectively, for the defaunated subperiod but were not different among treatments. Ammonia concentration was 33% higher in the faunated fermenters but was not affected by treatment. Defaunation increased the flow of nonammonia N and bacterial N from the fermenters. Protozoal counts were not different among treatments, but bromoethanesulfonate increased the generation time from 43.2 to 55.6 h. Methanogenesis was unaffected by defaunation but tended to be increased by unsaturated fat. Defaunation did not affect total volatile fatty acid production but decreased the acetate:propionate ratio; monensin increased production of isovalerate and valerate. Biohydrogenation of unsaturated fatty acids was impaired in the defaunated fermenters because effluent flows of oleic, linoleic, and linolenic acids were 60, 77, and 69% higher, and the ratio of vaccenic acid:unsaturated FA ratio was decreased by 34% in the effluent. This ratio was increased in both subperiods with the added fat diet, indicating an accumulation of

  5. Quantification and characterization of cell wall polysaccharides released by non-Saccharomyces yeast strains during alcoholic fermentation.

    Science.gov (United States)

    Giovani, Giovanna; Rosi, Iolanda; Bertuccioli, Mario

    2012-11-15

    In order to improve knowledge about the oenological characteristics of non-Saccharomyces yeast strains, and to reconsider their contribution to wine quality, we studied the release of polysaccharides by 13 non-Saccharomyces strains of different species (three wine yeasts, six grape yeasts, and three spoilage yeasts) during alcoholic fermentation in synthetic must. Three Saccharomyces cerevisiae strains were included for comparison. All of the non-Saccharomyces strains released polysaccharides into fermentation medium; the amount released depended on the yeast species, the number of cells formed and their physiological conditions. Normalizing the quantity of macromolecules released to the cell biomass revealed that most non-Saccharomyces strains produced a greater quantity of polysaccharides compared to S. cerevisiae strains after 7 and 14days of fermentation. This capacity was particularly expressed in the studied wine spoilage yeasts (Saccharomycodes ludwigii, Zygosaccharomyces bailii, and Brettanomyces bruxellensis). Chemical characterization of exocellular polysaccharides produced by non-Saccharomyces yeasts revealed them to essentially be mannoproteins with high mannose contents, ranging from 93% for S'codes. ludwigii to 73-74% for Pichia anomala and Starmerella bombicola. Protein contents varied from 9% for P. anomala to 29% for Z. bailii. These compositions were very similar to those of the S. cerevisiae strains, and to the chemical composition of the cell wall mannoproteins of different yeast species. The presence of galactose, in addition to mannose and glucose, in the exocellular polysaccharides released by Schizosaccharomyces pombe, confirmed the parietal nature of the polysaccharides released by non-Saccharomyces yeasts; only this species has a galactomannan located in the outer layer of the cell wall.

  6. Identification of yeasts during alcoholic fermentation of tchapalo, a traditional sorghum beer from Côte d'Ivoire.

    Science.gov (United States)

    N'guessan, Kouadio Florent; Brou, Kouakou; Jacques, Noémie; Casaregola, Serge; Dje, Koffi Marcellin

    2011-05-01

    This study investigated the diversity and dynamics of yeasts involved in alcoholic fermentation of a traditional sorghum beer from Côte d'Ivoire, tchapalo. A total of 240 yeast strains were isolated from fermenting sorghum wort inoculated with dry yeast from two geographic regions of Côte d'Ivoire (Abidjan and Bondoukou). Initial molecular identification to the species level was carried out using RFLP of PCR-amplified internal transcribed spacers of rDNA (ITS1-5.8S-ITS2). Ten different profiles were obtained from the restriction of PCR products with the three endonucleases HaeIII, CfoI and HinfI. Sequence analysis of the D1/D2 domain of the 26S rDNA and the ACT1 gene allowed us to assign these groups to six different species: Saccharomyces cerevisiae-like, Candida tropicalis, Pichia kudriavzevii, Pichia kluyveri, Kodamaea ohmeri and Meyerozyma caribbica. The most frequent species associated with tchapalo fermentation was S. cerevisiae-like (87.36%), followed by C. tropicalis (5.45%) and M. caribbica (2.71%). S. cerevisiae-like strains were diploid heterozygotes and exhibited three to four nucleotides divergence from the type strain in the D1/D2 domain and several indels in the more discriminant sequence of the intron of the ACT1 gene. During the process, the yeast species isolated and their frequencies varied according to the geographic origin of the dry yeast. The occurrence of some species was sporadic and only two non-Saccharomyces species were found in the final product.

  7. Effective multiple stages continuous acetone-butanol-ethanol fermentation by immobilized bioreactors: Making full use of fresh corn stalk.

    Science.gov (United States)

    Chang, Zhen; Cai, Di; Wang, Yong; Chen, Changjing; Fu, Chaohui; Wang, Guoqing; Qin, Peiyong; Wang, Zheng; Tan, Tianwei

    2016-04-01

    In order to make full use of the fresh corn stalk, the sugar containing juice was used as the sole substrate for acetone-butanol-ethanol production without any nutrients supplement, and the bagasse after squeezing the juice was used as the immobilized carrier. A total 21.34g/L of ABE was produced in batch cells immobilization system with ABE yield of 0.35g/g. A continuous fermentation containing three stages with immobilized cells was conducted and the effect of dilution rate on fermentation was investigated. As a result, the productivity and ABE solvents concentration reached 0.80g/Lh and 19.93g/L, respectively, when the dilution rate in each stage was 0.12/h (corresponding to a dilution rate of 0.04/h in the whole system). And the long-term operation indicated the continuous multiple stages ABE fermentation process had good stability and showed the great potential in future industrial applications.

  8. Determination of yeast viability during a stress-model alcoholic fermentation using reagent-free microscopy image analysis.

    Science.gov (United States)

    Tibayrenc, Pierre; Ghommidh, Charles; Preziosi-Belloy, Laurence

    2011-01-01

    A dedicated microscopy imaging system including automated positioning, focusing, image acquisition, and image analysis was developed to characterize a yeast population with regard to cell morphology. This method was used to monitor a stress-model alcoholic fermentation with Saccharomyces cerevisiae. Combination of dark field and epifluorescence microscopy after propidium iodide staining for membrane integrity showed that cell death went along with important changes in cell morphology, with a cell shrinking, the onset of inhomogeneities in the cytoplasm, and a detachment of the plasma membrane from the cell wall. These modifications were significant enough to enable a trained human operator to make the difference between dead and viable cells. Accordingly, a multivariate data analysis using an artificial neural network was achieved to build a predictive model to infer viability at single-cell level automatically from microscopy images without any staining. Applying this method to in situ microscope images could help to detect abnormal situations during a fermentation course and to prevent cell death by applying adapted corrective actions.

  9. Fermentation Technology of Apple Alcoholic Beverage%发酵苹果含醇饮料的工艺研究

    Institute of Scientific and Technical Information of China (English)

    赵菲; 关文强; 王愈

    2014-01-01

    以富士苹果为原料,以酵母菌和乳酸菌为发酵菌种,经过预处理、榨汁、发酵等工序,研制风味独特的含醇饮料,并通过感官质量评价和正交试验确定其最佳工艺配方。结果表明:发酵温度为30℃,发酵时间为4 d的发酵条件下,最佳配方为每100 mL苹果汁中添加活化的酵母菌7 mL、活化的乳酸菌7 mL、蔗糖11 g。另外,研究了适宜的菌种添加工艺参数,结果表明先添加乳酸菌,发酵2d之后再添加酵母菌时所得到的发酵苹果汁感官品质好。%Fuji apple was used as the raw material to produce the special taste alcoholic beverage with yeasts and lactic acid bacteria. The optimal processing technique was established by sensory evaluation and orthogonal test. The result showed that the optimal fermentation condition was inoculation amount 7mL activatory yeast and 7mL activatory lactic acid bacteria per 100 mL apple juice added with 11 g sugar at 30℃for 4 days. Then parameters for adding strains into the apple juice also were studied. Apple alcoholic beverage of good sensory quality could be produced when yeast was added into apple juice after 2 days of lactic acid bacteria fermentation.

  10. On-Line Optimizing Control of a Simulated Continuous Yeast Fermentation

    DEFF Research Database (Denmark)

    Andersen, Maria Y.; Asferg, L.; Brabrand, H.;

    1989-01-01

    On-line optimizing control of a simulated fermentation is investigated using a non-segregated dynamic model of aerobic glucose limited growth of saccharomyces cerevisiae. The optimization procedure is carried out with an underlying adaptive regulator to stabilize the culture. This stabilization...... is especially important during the setpoint changes specified by the optimizing routine. A linear ARMAX model structure is used for the fermentation process with dilution rate as input and biomass as output variable. The parameters of the linear model structure are estimated using a pseudo linear regression...

  11. Novel and neglected issues of acetone-butanol-ethanol (ABE) fermentation by clostridia: Clostridium metabolic diversity, tools for process mapping and continuous fermentation systems.

    Science.gov (United States)

    Patakova, Petra; Linhova, Michaela; Rychtera, Mojmir; Paulova, Leona; Melzoch, Karel

    2013-01-01

    This review emphasises the fact that studies of acetone-butanol-ethanol (ABE) fermentation by solventogenic clostridia cannot be limited to research on the strain Clostridium acetobutylicum ATCC 824. Various 1-butanol producing species of the genus Clostridium, which differ in their patterns of product formation and abilities to ferment particular carbohydrates or glycerol, are described. Special attention is devoted to species and strains that do not produce acetone naturally and to the utilisation of lactose, inulin, glycerol and mixtures of pentose and hexose carbohydrates. Furthermore, process-mapping tools based on different principles, including flow cytometry, DNA microarray analysis, mass spectrometry, Raman microscopy, FT-IR spectroscopy and anisotropy of electrical polarisability, which might facilitate fermentation control and a deeper understanding of ABE fermentation, are introduced. At present, the methods with the greatest potential are flow cytometry and transcriptome analysis. Flow cytometry can be used to visualise and capture cells within clostridial populations as they progress through the normal cell cycle, in which symmetric and asymmetric cell division phases alternate. Cell viability of a population of Clostridium pasteurianum NRRL B-598 was determined by flow cytometry. Transcriptome analysis has been used in various studies including the detection of genes expressed in solventogenic phase, at sporulation, in the stress response, to compare expression patterns of different strains or parent and mutant strains, for studies of catabolite repression, and for the detection of genes involved in the transport and metabolism of 11 different carbohydrates. Interestingly, the results of transcriptome analysis also challenge our earlier understanding of the role of the Spo0A regulator in initiation of solventogenesis in C. acetobutylicum ATCC 824. Lastly, the review describes other significant recent discoveries, including the deleterious effects of

  12. Digestion during continuous culture fermentation when replacing perennial ryegrass with barley and steam-flaked corn.

    Science.gov (United States)

    Wales, W J; Kolver, E S; Egan, A R

    2009-01-01

    The objective of this study was to quantify the optimal inclusion rate of grain required to maximize nutrient digestion of a diet based on highly digestible pasture. It was hypothesized that maximum digestion would occur at a rate of grain inclusion that resulted in a culture pH of 6.0, reflecting the pH below which fiber digestion would be expected to be compromised. Four dual-flow continuous culture fermenters were used to establish the effects on digestion of replacing freeze-dried, highly digestible ryegrass with 0, 15, 30, and 45% of dry matter as 60% barley, 35% steam-flaked corn, and 5% molasses mix. The respective composite diets were fed twice daily to mimic intake patterns observed in dairy cows offered supplements during milking and offered half their daily allowance of pasture after each milking. Digesta samples were collected during the last 3 d of each of four 9-d experimental periods. Average daily culture pH decreased linearly as proportion of cereal grain in the diet increased, with average daily pH ranging from 6.29 to 5.74. Concentrations of neutral detergent fiber and total fatty acids decreased linearly with increasing proportion of cereal grain in the diet. Digestion of organic matter (OM) was maximized at an interpolated value of 24% grain inclusion and culture pH of 6.0, but the difference in the OM digestibility over the range of grain treatments from 0 to 45% was small (3 percentage units) despite pH changes over a range of 6.3 to 5.7. The relatively small change in OM digestibility was explained by reduced fiber and crude protein digestibilities being balanced by an increased digestion of nonstructural carbohydrate. Although different relationships between ruminal pH and digestibility appear to exist when cows are fed pasture alone compared with a total mixed ration, when starch supplements are included in pasture diets, the relationships associated with feeding a total mixed ration may then be more likely to apply.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-11-15

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

  14. A Feasibility Study on Monitoring Residual Sugar and Alcohol Strength in Kiwi Wine Fermentation Using a Fiber-Optic FT-NIR Spectrometry and PLS Regression.

    Science.gov (United States)

    Wang, Bingqian; Peng, Bangzhu

    2017-02-01

    This work aims to investigate the potential of fiber-optic Fourier transform-near-infrared (FT-NIR) spectrometry associated with chemometric analysis, which will be applied to monitor time-related changes in residual sugar and alcohol strength during kiwi wine fermentation. NIR calibration models for residual sugar and alcohol strength during kiwi wine fermentation were established on the FT-NIR spectra of 98 samples scanned in a fiber-optic FT-NIR spectrometer, and partial least squares regression method. The results showed that R(2) and root mean square error of cross-validation could achieve 0.982 and 3.81 g/L for residual sugar, and 0.984 and 0.34% for alcohol strength, respectively. Furthermore, crucial process information on kiwi must and wine fermentations provided by fiber-optic FT-NIR spectrometry was found to agree with those obtained from traditional chemical methods, and therefore this fiber-optic FT-NIR spectrometry can be applied as an effective and suitable alternative for analyses and monitoring of those processes. The overall results suggested that fiber-optic FT-NIR spectrometry is a promising tool for monitoring and controlling the kiwi wine fermentation process.

  15. Modeling the alcoholic fermentation of xylose by Pichia stipitis using a qualitative reasoning approach

    Energy Technology Data Exchange (ETDEWEB)

    Guerrin, F. (INRA (Institut National de la Recherche Agronomique), Biometrics and Artificial Intelligence Station, 31 - Castanet-Tolosan (France)); Delgenes, J.P. (INRA, Biotechnological Lab. for Food Industry Environment, 11 - Narbonne (France)); Moletta, R. (INRA, Biotechnological Lab. for Food Industry Environment, 11 - Narbonne (France))

    1994-03-01

    Qualitative Reasoning is a set of Artificial Intelligence theories, methods, and techniques that provide an answer to modeling problems in domains in which one can have a clear notion of how a system is functioning without being able to express it as classical mathematical equations, and where is posed the problem of using jointly quantitative and qualitative data, as well as processing a big amount of complex knowledge. SIMAO ('a System to Interpret Measurements And Observations') is an attempt to deal with such problems. Although primarily devised for heterogeneous data interpretation in hydroecology, it was thought possible to use SIMAO in a wider context, like biotechnological processes. Starting from specific problems posed by a batch fermentation, the D-xylose conversion into ethanol by the yeast Pichia stipitis, this paper descibes how was built and used a SIMAO model aimed at predicting the fermentation issue from initial conditions, i.e. set-points values and substrate concentration. (orig.)

  16. Bioactive compounds derived from the yeast metabolism of aromatic amino acids during alcoholic fermentation.

    Science.gov (United States)

    Mas, Albert; Guillamon, Jose Manuel; Torija, Maria Jesus; Beltran, Gemma; Cerezo, Ana B; Troncoso, Ana M; Garcia-Parrilla, M Carmen

    2014-01-01

    Metabolites resulting from nitrogen metabolism in yeast are currently found in some fermented beverages such as wine and beer. Their study has recently attracted the attention of researchers. Some metabolites derived from aromatic amino acids are bioactive compounds that can behave as hormones or even mimic their role in humans and may also act as regulators in yeast. Although the metabolic pathways for their formation are well known, the physiological significance is still far from being understood. The understanding of this relevance will be a key element in managing the production of these compounds under controlled conditions, to offer fermented food with specific enrichment in these compounds or even to use the yeast as nutritional complements.

  17. Bioactive Compounds Derived from the Yeast Metabolism of Aromatic Amino Acids during Alcoholic Fermentation

    Science.gov (United States)

    Guillamon, Jose Manuel; Torija, Maria Jesus; Beltran, Gemma; Troncoso, Ana M.; Garcia-Parrilla, M. Carmen

    2014-01-01

    Metabolites resulting from nitrogen metabolism in yeast are currently found in some fermented beverages such as wine and beer. Their study has recently attracted the attention of researchers. Some metabolites derived from aromatic amino acids are bioactive compounds that can behave as hormones or even mimic their role in humans and may also act as regulators in yeast. Although the metabolic pathways for their formation are well known, the physiological significance is still far from being understood. The understanding of this relevance will be a key element in managing the production of these compounds under controlled conditions, to offer fermented food with specific enrichment in these compounds or even to use the yeast as nutritional complements. PMID:24895623

  18. Bioactive Compounds Derived from the Yeast Metabolism of Aromatic Amino Acids during Alcoholic Fermentation

    Directory of Open Access Journals (Sweden)

    Albert Mas

    2014-01-01

    Full Text Available Metabolites resulting from nitrogen metabolism in yeast are currently found in some fermented beverages such as wine and beer. Their study has recently attracted the attention of researchers. Some metabolites derived from aromatic amino acids are bioactive compounds that can behave as hormones or even mimic their role in humans and may also act as regulators in yeast. Although the metabolic pathways for their formation are well known, the physiological significance is still far from being understood. The understanding of this relevance will be a key element in managing the production of these compounds under controlled conditions, to offer fermented food with specific enrichment in these compounds or even to use the yeast as nutritional complements.

  19. Artificial neural network approach to modeling of alcoholic fermentation of thick juice from sugar beet processing

    Directory of Open Access Journals (Sweden)

    Jokić Aleksandar I.

    2012-01-01

    Full Text Available In this paper the bioethanol production in batch culture by free Saccharomyces cerevisiae cells from thick juice as intermediate product of sugar beet processing was examined. The obtained results suggest that it is possible to decrease fermentation time for the cultivation medium based on thick juice with starting sugar content of 5-15 g kg-1. For the fermentation of cultivation medium based on thick juice with starting sugar content of 20 and 25 g kg-1 significant increase in ethanol content was attained during the whole fermentation process, resulting in 12.51 and 10.95 dm3 m-3 ethanol contents after 48 h, respectively. Other goals of this work were to investigate the possibilities for experimental results prediction using artificial neural networks (ANNs and to find its optimal topology. A feed-forward back-propagation artificial neural network was used to test the hypothesis. As input variables fermentation time and starting sugar content were used. Neural networks had one output value, ethanol content, yeast cell number or sugar content. There was one hidden layer and the optimal number of neurons was found to be nine for all selected network outputs. In this study transfer function was tansig and the selected learning rule was Levenberg-Marquardt. Results suggest that artificial neural networks are good prediction tool for selected network outputs. It was found that experimental results are in very good agreement with computed ones. The coefficient of determination (the R-squared was found to be 0.9997, 0.9997 and 0.9999 for ethanol content, yeast cell number and sugar content, respectively.

  20. The nitrogen source impacts major volatile compounds released by Saccharomyces cerevisiae during alcoholic fermentation.

    Science.gov (United States)

    Barbosa, Catarina; Mendes-Faia, Arlete; Mendes-Ferreira, Ana

    2012-11-15

    Sulphur-containing amino acids, cysteine and methionine, are generally found in very low concentrations in grape-juice. The objective of this study was to identify the effects of methionine on aroma compounds formation. Nitrogen source effects on growth, fermentative behaviour and aroma compounds formation were evaluated in three strains of Saccharomyces cerevisiae cultivated in batch under moderate nitrogen concentration, 267mg YAN/L, supplied as di-ammonium phosphate (DAP), a mixture of amino acids with (AA) or without methionine (AA(wMet)), and a mixture of AA plus DAP. Fermentative vigour and final biomass yields were dependent on the nitrogen source, for each of the strains tested, in particular for EC1118. Additionally, despite the strain-dependent behaviour with respect to the basal level of H(2)S produced, the comparison of treatments AA and AA(wMet) showed that presence of methionine suppressed H(2)S production in all strains tested, and altered aroma compound formation, particularly some of those associated with fruity and floral characters which were consistently more produced in AA(wMet). Moreover, DAP supplementation resulted in a remarkable increase in H(2)S formation, but no correlation between sulphide produced and yeast fermentative vigour was observed. Results suggest that the use of different nitrogen sources results in the production of wines with divergent aroma profiles, most notably when EC1118 strain is used. Methionine determination and its management prior to fermentation are crucial for suppressing H(2)S and to endowing beverages with diverse sensory traits.

  1. High-gravity brewing: effects of nutrition on yeast composition, fermentative ability, and alcohol production.

    Science.gov (United States)

    Casey, G P; Magnus, C A; Ingledew, W M

    1984-09-01

    A number of economic and product quality advantages exist in brewing when high-gravity worts of 16 to 18% dissolved solids are fermented. Above this level, production problems such as slow or stuck fermentations and poor yeast viability occur. Ethanol toxicity has been cited as the main cause, as brewers' yeasts are reported to tolerate only 7 to 9% (vol/vol) ethanol. The inhibitory effect of high osmotic pressure has also been implicated. In this report, it is demonstrated that the factor limiting the production of high levels of ethanol by brewing yeasts is actually a nutritional deficiency. When a nitrogen source, ergosterol, and oleic acid are added to worts up to 31% dissolved solids, it is possible to produce beers up to 16.2% (vol/vol) ethanol. Yeast viability remains high, and the yeasts can be repitched at least five times. Supplementation does not increase the fermentative tolerance of the yeasts to ethanol but increases the length and level of new yeast cell mass synthesis over that seen in unsupplemented wort (and therefore the period of more rapid wort attenuation). Glycogen, protein, and sterol levels in yeasts were examined, as was the importance of pitching rate, temperature, and degree of anaerobiosis. The ethanol tolerance of brewers' yeast is suggested to be no different than that of sake or distillers' yeast.

  2. Fermentation of sugar to ethyl alcohol in the presence of proteolytic enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Coates, E.W.; Conde Julio, C.

    1963-06-11

    Sugar is fermented to EtOH by yeasts capable of elaborating zymase and proteolytic enzymes, the zymase component comprising exceptionally large amounts of phosphatase. Saccharomyces ellipsoideus was acclimated to 20% EtOH by growing on fresh pineapple juice in a medium consisting of malt sirup 15, sugar sirup 3, and pineapple juice 82%. An aqueous solution of 2000 gallons of sugar cane molasses in H/sub 2/O to give a Brix of 16/sup 0/ was placed in a 48,000-gallon fermentor. S. ellipsoideus with a cell constant of 1 x 10/sup 9/ cells/ml was added, with sufficient H/sub 2/SO/sub 4/ to adjust the pH to approximately 4.5. Fermentation was carried out at 35/sup 0/ until the Brix dropped to 8/sup 0/, after which it was brought back to 16/sup 0/ by adding 6000 gallons of sirup containing nutrients in H/sub 2/O. This process was repeated with another 6000 and then 2000 gallons of sirup. The total fermentation required 48 h and the EtOH content was 15.25% by volume. Te EtOH was recovered in the usual manner by removal of solids and fractional distillation.

  3. Alcohol Fermentation from Sugarcane Juice with Fruit Wine Yeast%果酒酵母对甘蔗汁的酒精发酵作用

    Institute of Scientific and Technical Information of China (English)

    陈赶林; 林波; 孙健; 李杨瑞

    2011-01-01

    A semi-product of sugarcane shrub, an alcoholic drink, was brewed from sugarcane juice by submerged fermentation using fruit wine yeast at room temperature. The characteristic parameter variations of sugarcane juice in the process of alcohol fermentation were investigated to determine the action mechanism of fruit wine yeast. The results showed that the alcohol fermentation cycle of sugarcane juice with 0. 15 to 0.30 g/L fruit wine yeast ranged from 14 to 20 days, the alcohol content was 4.5% , the acidity ranged from 1.8% to 2.4% , and the total sugar content decreased to 0.1%. The fermented juice was delightful, clearer and bright with yellowish-brown color. It exhibited full-bodied vinosity and soft taste. The present study has provided a reference for producing fruit drinks and vinegar drinks by the submerged fermentation of sugarcane juice.%以新鲜甘蔗压榨汁为原料,常温下用果酒酵母液态深层发酵酿制甘蔗果酒中间制品,探讨甘蔗汁酒精发酵过程中反应特性参数的变化。结果显示,使用0.15—0.30g/h的果酒酵母作用甘蔗汁,发酵周期为14~20d,发酵汁乙醇体积分数为4.5%,酸度为1.8%-2.4%,总糖为0.1%,发酵汁呈棕黄色,澄清透亮,酒香浓郁,味道柔和。

  4. Performance of several Saccharomyces strains for the alcoholic fermentation of sugar-sweetened high-strength wastewaters: Comparative analysis and kinetic modelling.

    Science.gov (United States)

    Comelli, Raúl N; Seluy, Lisandro G; Isla, Miguel A

    2016-12-25

    This work focuses on the performance of ten commercial Saccharomyces yeast strains in the batch alcoholic fermentation of sugars contained in selected industrial wastewaters from the soft drink industry. Fermentation has been applied successfully to treat these effluents prior to their disposal. Although many strains were investigated, similar behaviour was observed between all of the Saccharomyces strains tested. When media were inoculated with 2gL(-1) of yeast, all strains were able to completely consume the available sugars in less than 14h. Thus, any of the strains studied in this work could be used in non-conventional wastewater treatment processes based on alcoholic fermentation. However, ethanol production varied between strains, and these differences could be significant from a production point of view. Saccharomyces bayanus produced the most ethanol, with a mean yield of 0.44gethanolgsugarconsumed(-1) and an ethanol specific production rate of 5.96gethanol (Lh)(-1). As the assayed soft drinks wastewaters contain about 105gsugar/L of fermentable sugars, the concentration of ethanol achieved after the fermentations process was 46.2gethanol/L. A rigorous kinetic modelling methodology was used to model the Saccharomyces bayanus fermentation process. The kinetic model included coupled mass balances and a minimal number of parameters. A simple unstructured model based on the Andrews equation (substrate inhibition) was developed. This model satisfactorily described biomass growth, sugar consumption and bioethanol production. In addition to providing insights into the fermentative performance of potentially relevant strains, this work can facilitate the design of large-scale ethanol production processes that use wastewaters from the sugar-sweetened beverage industry as feedstock. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Effect of dilution rate and nutrients addition on the fermentative capability and synthesis of aromatic compounds of two indigenous strains of Saccharomyces cerevisiae in continuous cultures fed with Agave tequilana juice.

    Science.gov (United States)

    Morán-Marroquín, G A; Córdova, J; Valle-Rodríguez, J O; Estarrón-Espinosa, M; Díaz-Montaño, D M

    2011-11-15

    Knowledge of physiological behavior of indigenous tequila yeast used in fermentation process is still limited. Yeasts have significant impact on the productivity fermentation process as well as the sensorial characteristics of the alcoholic beverage. For these reasons a better knowledge of the physiological and metabolic features of these yeasts is required. The effects of dilution rate, nitrogen and phosphorus source addition and micro-aeration on growth, fermentation and synthesis of volatile compounds of two native Saccharomyces cerevisiae strains, cultured in continuous fed with Agave tequilana juice were studied. For S1 and S2 strains, maximal concentrations of biomass, ethanol, consumed sugars, alcohols and esters were obtained at 0.04 h⁻¹. Those concentrations quickly decreased as D increased. For S. cerevisiae S1 cultures (at D=0.08 h⁻¹) supplemented with ammonium phosphate (AP) from 1 to 4 g/L, concentrations of residual sugars decreased from 29.42 to 17.60 g/L and ethanol increased from 29.63 to 40.08 g/L, respectively. The S1 culture supplemented with AP was then micro-aerated from 0 to 0.02 vvm, improving all the kinetics parameters: biomass, ethanol and glycerol concentrations increased from 5.66, 40.08 and 3.11 g/L to 8.04, 45.91 and 4.88 g/L; residual sugars decreased from 17.67 g/L to 4.48 g/L; and rates of productions of biomass and ethanol, and consumption of sugars increased from 0.45, 3.21 and 7.33 g/L·h to 0.64, 3.67 and 8.38 g/L·h, respectively. Concentrations of volatile compounds were also influenced by the micro-aeration rate. Ester and alcohol concentrations were higher, in none aerated and in aerated cultures respectively.

  6. Hydrogen production from continuous flow, microbial reverse-electrodialysis electrolysis cells treating fermentation wastewater.

    Science.gov (United States)

    Watson, Valerie J; Hatzell, Marta; Logan, Bruce E

    2015-11-01

    A microbial reverse-electrodialysis electrolysis cell (MREC) was used to produce hydrogen gas from fermentation wastewater without the need for additional electrical energy. Increasing the number of cell pairs in the reverse electrodialysis stack from 5 to 10 doubled the maximum current produced from 60 A/m(3) to 120 A/m(3) using acetate. However, more rapid COD removal required a decrease in the anolyte hydraulic retention time (HRT) from 24 to 12 h to stabilize anode potentials. Hydrogen production using a fermentation wastewater (10 cell pairs, HRT=8 h) reached 0.9±0.1 L H2/Lreactor/d (1.1±0.1 L H2/g-COD), with 58±5% COD removal and a coulombic efficiency of 74±5%. These results demonstrated that consistent rates of hydrogen gas production could be achieved using an MREC if effluent anolyte COD concentrations are sufficient to produce stable anode potentials.

  7. Effect of organic loading rate on dark fermentative hydrogen production in the continuous stirred tank reactor and continuous mixed immobilized sludge reactor from waste pastry hydrolysate.

    Science.gov (United States)

    Han, Wei; Hu, Yunyi; Li, Shiyi; Nie, Qiulin; Zhao, Hongting; Tang, Junhong

    2016-12-01

    Waste pastry (6%, w/v) was hydrolyzed by the produced glucoamylase and protease to obtain the glucose (19.8g/L) and free amino nitrogen (179mg/L) solution. Then, the effect of organic loading rate (OLR) (8-40kgCOD/(m(3)d)) on dark fermentative hydrogen production in the continuous stirred tank reactor (CSTR) and continuous mixed immobilized sludge reactor (CMISR) from waste pastry hydrolysate was investigated and compared. The maximum hydrogen production rate of CSTR (277.76mL/(hL)) and CMISR (320.2mL/(hL)) were achieved at OLR of 24kgCOD/(m(3)d) and 32kgCOD/(m(3)d), respectively. Carbon recovery ranged from 75.2-84.1% in the CSTR and CMISR with the balance assumed to be converted to biomass. One gram waste pastry could produce 0.33g (1.83mmol) glucose which could be further converted to 79.24mL (3.54mmol) hydrogen in the CMISR or 91.66mL (4.09mmol) hydrogen in the CSTR. This is the first study which reports dark fermentative hydrogen production from waste pastry.

  8. Continuous monitoring of dough fermentation and bread baking by magnetic resonance microscopy.

    Science.gov (United States)

    Bajd, Franci; Serša, Igor

    2011-04-01

    The consumer quality of baked products is closely related with dough structure properties. These are developed during dough fermentation and finalized during its baking. In this study, magnetic resonance microscopy (MRM) was employed in a study of dough fermentation and baking. A small hot air oven was installed inside a 2.35-T horizontal bore superconducting magnet. Four different samples of commercial bread mixes for home baking were used to prepare small samples of dough that were inserted in the oven and allowed to rise at 33 °C for 112 min; this was followed by baking at 180 °C for 49 min. The entire process was followed by dynamic T(1)-weighted 3D magnetic resonance imaging with 7 min of temporal resolution and 0.23×0.23×1.5 mm(3) of spatial resolution. Acquired images were analyzed to determine time courses of dough pore distribution, dough volume and bread crust thickness. Image analysis showed that both the number of dough pores and the normalized dough volume increased in a sigmoid-like fashion during fermentation and decreased during baking due to the bread crust formation. The presented magnetic resonance method was found to be efficient in analysis of dough structure properties and in discrimination between different dough types.

  9. Effect of immobilized cells in calcium alginate beads in alcoholic fermentation.

    Science.gov (United States)

    Duarte, Juliana C; Rodrigues, J Augusto R; Moran, Paulo J S; Valença, Gustavo P; Nunhez, José R

    2013-05-30

    Saccharomyces cerevisiae cells were immobilized in calcium alginate and chitosan-covered calcium alginate beads and studied in the fermentation of glucose and sucrose for ethanol production. The batch fermentations were carried out in an orbital shaker and assessed by monitoring the concentration of substrate and product with HPLC. Cell immobilization in calcium alginate beads and chitosan-covered calcium alginate beads allowed reuse of the beads in eight sequential fermentation cycles of 10 h each. The final concentration of ethanol using free cells was 40 g L-1 and the yields using glucose and sucrose as carbon sources were 78% and 74.3%, respectively. For immobilized cells in calcium alginate beads, the final ethanol concentration from glucose was 32.9 ± 1.7 g L-1 with a 64.5 ± 3.4% yield, while the final ethanol concentration from sucrose was 33.5 ± 4.6 g L-1 with a 64.5 ± 8.6% yield. For immobilized cells in chitosan-covered calcium alginate beads, the ethanol concentration from glucose was 30.7 ± 1.4 g L-1 with a 61.1 ± 2.8% yield, while the final ethanol concentration from sucrose was 31.8 ± 6.9 g L-1 with a 62.1 ± 12.8% yield. The immobilized cells allowed eight 10 h sequential reuse cycles to be carried out with stable final ethanol concentrations. In addition, there was no need to use antibiotics and no contamination was observed. After the eighth cycle, there was a significant rupture of the beads making them inappropriate for reuse.

  10. Estimation of Temperature Dependent Parameters of a Batch Alcoholic Fermentation Process

    Science.gov (United States)

    de Andrade, Rafael Ramos; Rivera, Elmer Ccopa; Costa, Aline C.; Atala, Daniel I. P.; Filho, Francisco Maugeri; Filho, Rubens Maciel

    In this work, a procedure was established to develop a mathematical model considering the effect of temperature on reaction kinetics. Experiments were performed in batch mode in temperatures from 30 to 38°C. The microorganism used was Saccharomyces cerevisiae and the culture media, sugarcane molasses. The objective is to assess the difficulty in updating the kinetic parameters when there are changes in fermentation conditions. We conclude that, although the re-estimation is a time-consuming task, it is possible to accurately describe the process when there are changes in raw material composition if a re-estimation of parameters is performed.

  11. Effects of timing of corn silage supplementation on digestion, fermentation pattern, and nutrient flow during continuous culture fermentation of a short and intensive orchardgrass meal.

    Science.gov (United States)

    Gregorini, P; Soder, K J; Waghorn, G

    2010-08-01

    Using a dual-flow continuous culture fermenter system, this study evaluated the effect of timing of corn silage supplementation on ruminal digestion and nutrient flows following a short and intensive orchardgrass herbage meal. Treatments included 28 g dry matter (DM) of corn silage added either 9h (9BH; 0700 h) or 1h (1BH; 1500 h) before adding 42 g DM orchardgrass herbage or no corn silage (control; 70 g DM herbage). Herbage was fed as follows: 66% of the total herbage meal at 1600 h, 22% at 1720 h, and the remaining 12% at 1840 h. Effluent was analyzed for organic matter (OM), crude protein (CP), and neutral detergent fiber (NDF). Purine concentrations in effluent and bacterial isolates were used to estimate the partition of effluent N flow into bacterial and nonbacterial fractions, and to calculate true OM digestibility. Fermenters were sampled for pH, volatile fatty acids (VFA), and NH(3)-N at 0730, 1100, 1530, 1600, 1720, 1840, and 2000 h on d 10. Data were analyzed as a 3 x 4 Latin square experimental design. True digestibilities for OM (average of 78.5%) and CP (average of 84.6%), and apparent NDF digestibility (average of 82.7%) were not affected by treatment. Mean ruminal pH was lower for 9BH than for 1BH, averaging 5.6 and 6.5, respectively. Molar proportions of acetate were not affected by treatment. Propionate concentration was greater for 9BH than for 1BH, averaging 20.5 and 18.1mM, respectively. Diurnal patterns of pH, NH(3)-N, and acetate:propionate ratio were affected by treatment: 9BH had the lowest values for all measurements as the day progressed. The NH(3)-N concentration and effluent NH(3)-N flow were higher for 1BH (11.4 mg/100mL and 0.26 g/d, respectively) than for 9BH (8.8 mg/100mL and 0.20 g/d, respectively). Effluent NH(3)-N flow (as a % of total N flow) was the lowest for 9BH. Bacterial efficiency was not affected by treatments, with a mean of 10.5 g of N/kg of OM truly digested. Under the same resource allocation (pasture plus supplement

  12. Online monitoring alcoholic fermentation based on electrical conductivity%基于电导率的酒精发酵过程在线监测

    Institute of Scientific and Technical Information of China (English)

    李冲伟; 宋瑞清; 宋永; 李宏涛; 孙庆申

    2011-01-01

    To test the applicability of electrical conductivity for on-line monitoring alcohol fermentation process. The relationships between conductivity changes and reducing sugar contents, alcohol contents, or pH values were studied respectively. And the impacts of calcium chloride and ammonium sulfate on conductivity during alcoholic fermentation process were further explored. The results showed that there were certain logical relationships between conductivity changes and reducing sugar or alcohol contents respectively. That is, during the decrease stage of electrical conductivity, the electrical conductivity decreased with the decrease of reducing sugar, while increased with the increase of alcohol contents. The results indicated that conductivity could be used to reflect the contents of reducing sugar and alcohol indirectly. Meanwhile, the contents of alcohol and reducing sugar were in line with the parameters of the end of alcoholic fermentation when the conductivity reached its lowest point, then the end of alcoholic fermentation could be determined. There was a certain linear relationship between pH value and conductivity (the variation of pH value and conductivity were the same 60 h before fermentation.). The variation of conductivity could not be affected by calcium chloride and ammonium sulfate within a certain range. Therefore the conductivity could be applied in the on-line monitoring alcoholic fermentation progress and determining the end point of fermentation.%为了探讨电导率在酒精发酵过程在线临测的适用性,对酒精发酵过程中电导率与还原糖、酒精度、pH值的变化规律以及氯化钙和硫酸铵2种盐类对电导率的影响进行了研究.结果表明:电导率与还原糖和酒精度之间存在着一定的逻辑关系,即在电导率下降阶段,电导率随着还原糖的降低而下降,随着酒精度的增加而上升.利用电导率的测量值间接地反映还原糖和酒精度的变化;同时,电导率达到

  13. Survival rate of wine-related yeasts during alcoholic fermentation assessed by direct live/dead staining combined with fluorescence in situ hybridization.

    Science.gov (United States)

    Branco, Patrícia; Monteiro, Margarida; Moura, Patrícia; Albergaria, Helena

    2012-08-01

    Real-time detection of microorganisms involved in complex microbial process, such as wine fermentations, and evaluation of their physiological state is crucial to predict whether or not those microbial species will be able to impact the final product. In the present work we used a direct live/dead staining (LDS) procedure combined with fluorescence in situ hybridization (FISH) to simultaneously assess the identity and viability of Saccharomyces cerevisiae (Sc) and Hanseniaspora guilliermondii (Hg) during fermentations performed with single and mixed cultures. The population evolution of both yeasts was determined by plating and by LDS combined with species-specific FISH-probes labeled with Fluorescein. Since the FISH method involves the permeabilization of the cell membrane prior to hybridization and that it may influence the free diffusion of PI in and out of the cells, we optimized the concentration of this dye (0.5 μg of PI per 10(6) cells) for minimal diffusion (less than 2%). Fluorescent cells were enumerated by hemocytometry and flow cytometry. Results showed that the survival rate of Sc during mixed cultures was high throughout the entire process (60% of viable cells at the 9th day), while Hg began to die off at the 2nd day, exhibited 98% of dead cells at the 3rd day (45 g/l of ethanol) and became completely unculturable at the 4th day. However, under single culture fermentation the survival rate and culturability of Hg decreased at a much slower pace, exhibiting at the 7th day (67 g/l of ethanol) 8.7×10(4) CFU/ml and 85% of dead cells. Thus, our work demonstrated that the LDS-FISH method is able to simultaneously assess the viability and identity of these wine-related yeast species during alcoholic fermentation in a fast and reliable way. In order to validate PI-staining as a viability marker during alcoholic fermentation, we evaluated the effect of ethanol on the membrane permeability of Sc and Hg cells, as well as their capacity to recover membrane

  14. Biomarkers for detecting nitrogen deficiency during alcoholic fermentation in different commercial wine yeast strains.

    Science.gov (United States)

    Gutiérrez, Alicia; Chiva, Rosana; Beltran, Gemma; Mas, Albert; Guillamon, José Manuel

    2013-05-01

    Nitrogen deficiencies in grape musts are one of the main causes of stuck or sluggish wine fermentations. Several putative biomarkers were tested in order to analyze their appropriateness to detect nitrogen stress in the yeast. To this aim, four commercial wine strains (PDM, ARM, RVA and TTA) were grown in a synthetic grape must with different nitrogen concentrations. Trehalose accumulation, arginase activity and the expression of eleven genes were tested in these wine strains, known to have different nitrogen requirements. The overall response of the four strains was similar, with differences in response intensity (PDM and RVA with higher intensity) and response time (which was also related with nitrogen consumption time). Trehalose response was mostly related to entry into the stationary phase, whereas arginase activity was responsive to nitrogen depletion, although its measurement is too complicated to be used for routine monitoring during winemaking. The expression of the genes DAL4, DAL5, DUR3 and GAP1 was clearly related to nitrogen depletion and thus, GAP1 and DAL4 were selected as markers of nitrogen deficiency. In order to adapt expression analysis to winemaking conditions, the original strains were transformed into reporter strains based on the expression of green fluorescent protein (GFP) under control of the promoters for GAP1 and DAL4. The transformants had a similar fermentative capacity to the parental strains and were able to detect alterations in yeast physiological status due to nitrogen limitations.

  15. Mechanism of proanthocyanidins-induced alcoholic fermentation enhancement in Saccharomyces cerevisiae.

    Science.gov (United States)

    Li, Jingyuan; Zhao, Hongwei; Huang, Weidong

    2014-12-01

    Our previous work revealed proanthocyanidins (PAs) could pose significant enhancement on the activity of H(+)-ATPase and fermentation efficiency after a transient initial inhibition (Li et al in Am J Enol Vitic 62(4):512-518, 2011). The aim of the present work was to understand the possible mechanism for this regulation. At Day 0.5 the gene expression level of PMA1 in AWRI R2 strain supplemented with 1.0 mg/mL PAs was decreased by around 54 % with a 50 % and a 56.5 % increase in the concentration of intracellular ATP and NADH/NAD(+) ratio, respectively, compared to that of control. After the transient adaptation, the gene expression levels of PMA1 and HXT7 in PAs-treated cells were enhanced significantly accompanied by the decrease of ATP contents and NADH/NAD(+) ratio, which resulted in the high level of the activities of rate-limiting enzymes. PAs could pose significant effects on the fermentation via glucose transport, the energy and redox homeostasis as well as the activities of rate-limiting enzymes in glycolysis.

  16. Effects of the initial cell concentration on the alcoholic fermentation of cassava

    Energy Technology Data Exchange (ETDEWEB)

    Doin, P.A.; Olivo, J.E.; Varella, V.L.; Concone, B.R.; Pinto, A.G.

    1984-01-01

    Cassava is being considered in Brazil as the main alternative to sugarcane for the production of ethanol for industrial and fuel purposes, and efforts are being made to improve this technology. Among the possible improvements one of the most important is the increase in the saccharification and fermentation yields and productivities when these operators are accomplished simultaneously. In this work, using Saccharomyces cerevisiae, ethanol fermentations from cassava starch were carried out as a function of cell concentration ranging from 0.3 to 15.0 g/l. The main conclusions were that ethanol productivities and yields were not affected by the initial cell concentration unless this was below 0.3 to 0.6 g/l (dry base). Average ethanol productivities of about 4.0%/h were consistently obtained with ethanol yields ranging from 85 to 90%. Concerning reaction rates, it was found that unless very low values of initial cell concentration were used, the saccharification become the limiting step of the overall process.

  17. Alcoholic fermentation of xylose and mixed sugars using recombinant Saccharomyces cerevisiae engineered for xylose utilization.

    Science.gov (United States)

    Madhavan, Anjali; Tamalampudi, Sriappareddy; Srivastava, Aradhana; Fukuda, Hideki; Bisaria, Virendra S; Kondo, Akihiko

    2009-04-01

    Previously, a Saccharomyces cerevisiae strain was engineered for xylose assimilation by the constitutive overexpression of the Orpinomyces xylose isomerase, the S. cerevisiae xylulokinase, and the Pichia stipitis SUT1 sugar transporter genes. The recombinant strain exhibited growth on xylose, under aerobic conditions, with a specific growth rate of 0.025 h(-1), while ethanol production from xylose was achieved anaerobically. In the present study, the developed recombinant yeast was adapted for enhanced growth on xylose by serial transfer in xylose-containing minimal medium under aerobic conditions. After repeated batch cultivations, a strain was isolated which grew with a specific growth rate of 0.133 h(-1). The adapted strain could ferment 20 g l(-1) of xylose to ethanol with a yield of 0.37 g g(-1) and production rate of 0.026 g l(-1) h(-1). Raising the fermentation temperature from 30 degrees C to 35 degrees C resulted in a substantial increase in the ethanol yield (0.43 g g(-1)) and production rate (0.07 g l(-1) h(-1)) as well as a significant reduction in the xylitol yield. By the addition of a sugar complexing agent, such as sodium tetraborate, significant improvement in ethanol production and reduction in xylitol accumulation was achieved. Furthermore, ethanol production from xylose and a mixture of glucose and xylose was also demonstrated in complex medium containing yeast extract, peptone, and borate with a considerably high yield of 0.48 g g(-1).

  18. Continuous low-temperature methanol synthesis from syngas using alcohol promoters

    Energy Technology Data Exchange (ETDEWEB)

    Prasert Reubroycharoen; Tetsuji Yamagami; Tharapong Vitidsant; Yoshiharu Yoneyama; Motoaki Ito; Noritatsu Tsubaki [Toyama University, Toyama (Japan). Department of Material System & Life Science, School of Engineering

    2003-08-01

    Continuous low-temperature methanol synthesis from syngas containing CO{sub 2} on various Cu/ZnO catalysts was investigated by using a semibatch autoclave reactor. Methanol was easily produced at a temperature as low as 443 K and with a pressure of 50 bar with the aid of 2-butanol, which showed a very high efficiency with a one-pass yield of 47.0% and a selectivity of 98.9%. Methanol itself used as alcohol promoter exhibited a higher activity than other 1-alcohols because it has the lowest spatial effect. 2-Alcohols, however, exhibited the highest conversion among the same carbon number because of its well-balanced effects produced by their of electronic and spatial factors. The one-pass conversion was improved by increasing the catalyst weight because no thermodynamic limitations existed at low temperatures. The continuous low-temperature methanol synthesis is a very promising process because completely purified syngas is not necessary. 23 refs., 3 figs., 4 tabs.

  19. Effects of Partial Replacement of Corn with Glycerin on Ruminal Fermentation in a Dual-Flow Continuous Culture System.

    Science.gov (United States)

    Del Bianco Benedeti, Pedro; Galoro da Silva, Lorrayny; Marostegan de Paula, Eduardo; Shenkoru, Teshome; Marcondes, Marcos Inácio; Monteiro, Hugo Fernando; Amorati, Brad; Yeh, Yenling; Poulson, Simon Roger; Faciola, Antonio Pinheiro

    2015-01-01

    The objective of this study was to evaluate the effects of partially replacing dry ground corn with glycerin on ruminal fermentation using a dual-flow continuous culture system. Six fermenters (1,223 ± 21 ml) were used in a replicated 3x3 Latin square arrangement with three periods of 10 d each, with 7 d for diet adaptation and 3 d for sample collections. All diets contained 75% concentrate and three dietary glycerin levels (0, 15, and 30% on dry matter basis), totaling six replicates per treatment. Fermenters were fed 72 g of dry matter/d equally divided in two meals/d, at 0800 and 2000 h. Solid and liquid dilution rates were adjusted daily to 5.5 and 11%/h, respectively. On d 8, 9, and 10, samples of 500 ml of solid and liquid digesta effluent were mixed, homogenized, and stored at -20°C. Subsamples of 10 ml were collected and preserved with 0.2 mL of a 50% H2SO4 solution for later determination of NH3-N and volatile fatty acids. Microbial biomass was isolated from fermenters for chemical analysis at the end of each experimental period. Data were analyzed using the MIXED procedure in SAS with α = 0.05. Glycerin levels did not affect apparent digestibility of DM (PLin. = 0.13; PQuad. = 0.40), OM (PLin. = 0.72; PQuad. = 0.15), NDF (PLin. = 0.38; PQuad. = 0.50) and ADF (PLin. = 0.91; PQuad. = 0.18). Also, glycerin inclusion did not affect true digestibility of DM (PLin. = 0.35; PQuad. = 0.48), and OM (PLin. = 0.08; PQuad. = 0.19). Concentrations of propionate (P glycerin inclusion. Linear increases on NH3-N concentration in digesta effluent (P glycerin inclusion in the diets. Crude protein digestibility (P = 0.04) and microbial N flow (P = 0.04) were greater in the control treatment compared with the other treatments and responded quadratically with glycerin inclusion. Furthermore, the inclusion of glycerin linearly decreased (P = 0.02) non-ammonia N flow. Glycerin levels did not affect the flows of total N (PLin. = 0.79; PQuad. = 0.35), and dietary N (PLin. = 0

  20. Impact of alternative technique to ageing using oak chips in alcoholic or in malolactic fermentation on volatile and sensory composition of red wines.

    Science.gov (United States)

    Gómez García-Carpintero, E; Gómez Gallego, M A; Sánchez-Palomo, E; González Viñas, M A

    2012-09-15

    This paper reports on a complete study of the effect of wood, in the form of oak chips, on the volatile composition and sensory characteristics of Moravia Agria wines added at different stages of the fermentation process. Aroma compounds were analyzed by gas chromatography-mass spectrometry (GC-MS). Sensory profile was evaluated by experienced wine-testers. Oak chips were added to wines in two dose rates at different stages of the winemaking process: during alcoholic fermentation (AF), during malolactic fermentation (MLF) and in young, red Moravia Agria wine. Wines fermented with oak chips during AF showed higher concentrations of the ethyl esters of straight-chain fatty acids, ethyl, hexyl, isoamyl acetates and superior alcohols than the control wines. The higher concentrations of benzene compound, oak lactones and furanic compounds were found in wines in contact with oak chips during MLF. The use of oak chips gives rise to a different sensorial profile of wines depending of the point of addition. Higher intensities of woody, coconut, vanilla and sweet spices descriptors were obtained when a large dose rate of chips was employed.

  1. Real-Time DNP NMR Observations of Acetic Acid Uptake, Intracellular Acidification, and of Consequences for Glycolysis and Alcoholic Fermentation in Yeast

    DEFF Research Database (Denmark)

    Jensen, Pernille Rose; Karlsson, Magnus; Lerche, Mathilde Hauge

    2013-01-01

    Uptake and upshot in vivo: Straightforward methods that permit the real-time observation of organic acid influx, intracellular acidification, and concomitant effects on cellular-reaction networks are crucial for improved bioprocess monitoring and control (see scheme). Herein, dynamic nuclear pola...... polarization (DNP) NMR is used to observe acetate influx, ensuing intracellular acidification and the metabolic consequences on alcoholic fermentation and glycolysis in living cells....

  2. Alcoholic fermentation of xylose by immobilized Pichia stipitis in a fixed-bed pulsed bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Sanroman, A.; Chamy, R.; Nunez, M.J.; Lema, J.M. (Santiago de Compostela Univ. (Spain). Dept. of Chemical Engineering)

    1994-01-01

    To enhance the productivity of the fermentation of xylose by Pichia stipitis, it is important to use bioreactors that (a) allow a high concentration of yeast (this can be achieved by using immobilised yeasts), (b) reduce the diffusional limitations resulting from dead volume (due mainly to the supplied and produced gas), and (c) diminish the effect of inhibition by ethanol. The process of immobilising P. stipitis in [kappa]-carrageenan was amended through the subsequent treatment of the bioparticles with a hardening agent (Al[sup 3+]). The variables examined were the cellular mass/gel mass ratio, the concentration of the hardening solution, and the contact time between the bioparticles and the hardening agent. (author)

  3. Alcoholic fermentation by the wild yeasts under thermal, osmotic and ethanol stress

    Directory of Open Access Journals (Sweden)

    Rosimeire Oenning da Silva

    2013-04-01

    Full Text Available This study aimed to explore the variability in the metabolism of nine wild yeasts isolated from the sugarcane juice from a distillery in the Brazilian State of Mato Grosso. Cell viability under the stress conditions was evaluated. The yeasts were inoculated in the test tubes containing sugarcane juice adjusted from 12 to 21º Brix, ethanol from 6 to 12% in volume and temperature at 30, 35 and 40ºC. The viability was established by the growth in Petri dishes and visually by the CO2 production in the test tubes. None of the evaluated yeasts showed simultaneous resistance to the three stress conditions. The potential of yeast BB.09 could be emphasized due to its ability to ferment up to12% ethanol at 30°C.

  4. Production of alcohol by simultaneous saccharification and fermentation of low-grade wheat flour

    Directory of Open Access Journals (Sweden)

    Marcos Antonio das Neves

    2006-05-01

    Full Text Available Two samples of low-grade wheat flour, namely low-grade 1 (LG1 and low-grade 2 (LG2, with different carbohydrate and fibrous content, were used as substrates. The samples were liquefied using various concentrations of alpha- or beta-amylase, in order to optimize the production of fermentable sugars; the enzyme alpha-amylase revealed higher performance. After liquefaction, the simultaneous saccharification and fermentation was conducted in a jar fermentor. Amyloglucosidase was used for saccharification, and dry baker's yeast, S. cerevisiae, for fermentation simultaneously. Glucose was consumed promptly in both cases, LG1 and LG2; ethanol production was considerably higher in LG1 (38.6 g/L, compared to LG2 (24.9 g/L. The maximum ATP production was observed early in the SSF process. LG1 revealed higher potential as substrate for ethanol production.Dois lotes de amostras de resíduo de farinha de trigo com teor reduzido de amido, especificamente designadas como amostra 1 (LG1 e amostra 2 (LG2, foram utilizados como substrato para fermentação alcoólica. Inicialmente as amostras foram hidrolisadas utilizando-se diferentes concentrações de alfa- ou beta-amilase, com o objetivo de otimizar a produção de açúcares fermentáveis; a enzima alfa-amilase apresentou melhor desempenho. O processo simultâneo de sacarificação e fermentação foi conduzido logo após a hidrólise do amido, em um fermentador com volume de 2 L; o meio contendo amido hidrolisado foi inoculado com amiloglucosidase (enzima utilizada para sacarificação e levedura de panificação desidratada (para fermentação, simultaneamente. Amostras do meio de fermentação foram retiradas regularmente para análise dos teores de glucose, maltose, açúcares redutores e etanol. O teor de Adenosina Tri-Fosfato (ATP também foi analisado. O açúcar glucose foi completamente consumido no início da fermentação, tanto no caso da amostra LG1, quanto LG2, sendo que a produção de etanol

  5. Alcohol

    Science.gov (United States)

    If you are like many Americans, you drink alcohol at least occasionally. For many people, moderate drinking ... risky. Heavy drinking can lead to alcoholism and alcohol abuse, as well as injuries, liver disease, heart ...

  6. Changes of primary higher alcohols during the traditional and new rice wine fermentation process%新旧工艺黄酒发酵过程中主要高级醇的变化研究

    Institute of Scientific and Technical Information of China (English)

    周建弟; 蒋予箭; 邹慧君; 谭檑华; 沈斌

    2012-01-01

    The gas chromatography method was used to determine the primary higher alcohols, such as n-propyl alcohol, isobutyl alcohol, isoamyl alcohol, β-phenylethyl alcohol, during the traditional and new rice wine fermentation, respectively. The results indicated that the total higher alcohols content increased along with the fermentation, and the increment during the primary fermentation was obviously faster than that of later fermentation, to the new fermentation process, 82% of higher alcohols content was synthesized in the primary fermentation stage, whereas, the value was 73% in the traditional technology. When the fermentation was over, the total higher alcohols content of new technology was 56.60mg/L, which was higher than that of the traditional one. The ratio of n-propyl alcohol, isobutyl alcohol, isoamyl alcohol and β-phenylethyl alcohol was close to 1:2:5:1, which had no obvious change during the fermentation and was not dependent on the type of fermentation process.%文章用气相色谱法对新工艺及传统工艺黄酒发酵过程中的主要高级醇——正丙醇、异丁醇、异戊醇、β-苯乙醇进行了跟踪测定,结果表明,2种工艺黄酒在发酵过程中总高级醇含量一直处于上升状态,前发酵阶段上升速率要明显高于后发酵.新工艺条件下黄酒中82%的高级醇在前发酵阶段形成,传统工艺下这个比例为73%,发酵结束时新工艺黄酒总高级醇含量比传统工艺黄酒高56.60mg/L.发酵过程中高级醇组分间的比例——正丙醇∶异丁醇∶异戊醇∶苯乙醇近似为1∶2∶5∶1,这个比值在整个发酵过程中变化不大,且与新旧工艺路线无关.

  7. Continuous Fermentation of Clostridium tyrobutyricum with Partial Cell Recycle as a Long-Term Strategy for Butyric Acid Production

    Directory of Open Access Journals (Sweden)

    Edgar C. Clausen

    2012-08-01

    Full Text Available In making alternative fuels from biomass feedstocks, the production of butyric acid is a key intermediate in the two-step production of butanol. The fermentation of glucose via Clostridium tyrobutyricum to butyric acid produces undesirable byproducts, including lactic acid and acetic acid, which significantly affect the butyric acid yield and productivity. This paper focuses on the production of butyric acid using Clostridium tyrobutyricum in a partial cell recycle mode to improve fermenter yield and productivity. Experiments with fermentation in batch, continuous culture and continuous culture with partial cell recycle by ultrafiltration were conducted. The results show that a continuous fermentation can be sustained for more than 120 days, which is the first reported long-term production of butyric acid in a continuous operation. Further, the results also show that partial cell recycle via membrane ultrafiltration has a great influence on the selectivity and productivity of butyric acid, with an increase in selectivity from ≈9% to 95% butyric acid with productivities as high as 1.13 g/Lh. Continuous fermentation with low dilution rate and high cell recycle ratio has been found to be desirable for optimum productivity and selectivity toward butyric acid and a comprehensive model explaining this phenomenon is given.

  8. 辅料及发酵条件对食醋酒精发酵工艺影响研究%Effect of adjuncts and fermentation condition on alcohol fermentation of vinegar

    Institute of Scientific and Technical Information of China (English)

    滕占才; 李志江; 王波; 杨宏志

    2011-01-01

    The optimal conditions of alcoholic fermentation of vinegar were investigated through single factors experiment, in which the sorghum was used as raw materials and Daqu and honey were used as adjuncts.The optimal conditions were as followed: addition of Daqu 60%, honey content 10%, fermentation time 7d, fermentation temperature 25℃~30℃, yeast inoculum 2×l07cfu/g and initial pH 4.5.Under these conditions, the alcohol content reached 7.38%vol.%以高粱为主要原料,大曲和蜂蜜为辅助原料,利用单因素实验方法,以酒精度和还原糖含量为指标,确定了食醋酒精发酵阶段的最佳工艺参数.结果表明,大曲添加量为60%,蜂蜜添加量为10%;发酵时间为7d,发酵温度25℃~30℃,酵母接种量为2×107个/g,初始pH值为4.5最佳发酵参数,经验证试验,最终得到的酒精度为7.38%vo1.

  9. Microbial diversity of traditional Vietnamese alcohol fermentation starters (banh men) as determined by PCR-mediated DGGE.

    Science.gov (United States)

    Thanh, Vu Nguyen; Mai, Le Thuy; Tuan, Duong Anh

    2008-12-10

    The diversity of fungi and bacteria associated with traditional Vietnamese alcohol fermentation starters (banh men) was investigated by PCR-mediated DGGE. From 52 starter samples, 13 species of fungi (including yeasts) and 23 species of bacteria were identified. The fungal composition of the starters was consistent with little variation among samples. It consisted of amylase producers (Rhizopus oryzae, R. microsporus, Absidia corymbifera, Amylomyces sp., Saccharomycopsis fibuligera), ethanol producers (Saccharomyces cerevisiae, Issatchenkia sp., Pichia anomala, Candida tropicalis, P. ranongensis, Clavispora lusitaniae), and (opportunistic) contaminants (Xeromyces bisporus, Botryobasidium subcoronatum). The bacterial microflora of starters was highly variable in species composition and dominated by lactic acid bacteria (LAB). The most frequent LAB were Pediococcus pentosaceus, Lactobacillus plantarum, L. brevis, Weissella confusa, and W. paramesenteroides. Species of amylase-producing Bacillus (Bacillus subtilis, B. circulans, B. amyloliquefaciens, B. sporothermodurans), acetic acid bacteria (Acetobacter orientalis, A. pasteurianus), and plant pathogens/environment contaminants (Burkholderia ubonensis, Ralstonia solanacearum, Pelomonas puraquae) were also detected. Fungal DGGE was found to be useful for evaluating starter type and starter quality. Moreover, in view of the high biological diversity of these substrates, bacterial DGGE may be useful in determining the identity of a starter. The constant occurrence of opportunistic contaminants highlights the need for careful examination of the role of individual components in starters.

  10. Continuous xylose fermentation by Clostridium acetobutylicum--kinetics and energetics issues under acidogenesis conditions.

    Science.gov (United States)

    Procentese, Alessandra; Raganati, Francesca; Olivieri, Giuseppe; Russo, Maria Elena; Salatino, Piero; Marzocchella, Antonio

    2014-07-01

    The paper reports the assessment of the growth kinetics of Clostridium acetobutylicum DSM 792 adopting xylose as carbon source. Xylose is the fundamental component of hemicellulose hydrolysis, a relevant fraction of lignocellulosic feedstocks for biofuel production. Tests were carried out in a CSTR operated under controlled pH. The effects of acids (acetic and butyric) and solvents (acetone, ethanol and butanol) on the fermentation were investigated. The conversion process was characterized under steady-state conditions in terms of concentration of xylose, cells, acids, and pH. The growth kinetics was expressed by means of a multiple product inhibition and it was able to predict microorganism growth rate under a broad interval of operating conditions, even those typical of solvents production. The mass fractional yield of biomass and products were expressed as a function of the specific growth rate taking into account the Pirt model. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Fermentation Industry.

    Science.gov (United States)

    Grady, C. P. L., Jr.; Grady, J. K.

    1978-01-01

    Presents a literature review of wastes from the fermentation industry, covering publications of 1976-77. This review focuses on: (1) alcoholic beverage production; (2) pharmaceuticals and biochemicals production; and (3) biomass production. A list of 62 references is also presented. (HM)

  12. Fermentation Industry.

    Science.gov (United States)

    Grady, C. P. L., Jr.; Grady, J. K.

    1978-01-01

    Presents a literature review of wastes from the fermentation industry, covering publications of 1976-77. This review focuses on: (1) alcoholic beverage production; (2) pharmaceuticals and biochemicals production; and (3) biomass production. A list of 62 references is also presented. (HM)

  13. The effect of Maillard reaction products and yeast strain on the synthesis of key higher alcohols and esters in beer fermentations.

    Science.gov (United States)

    Dack, Rachael E; Black, Gary W; Koutsidis, Georgios; Usher, St John

    2017-10-01

    The effect of Maillard reaction products (MRPs), formed during the production of dark malts, on the synthesis of higher alcohols and esters in beer fermentations was investigated by headspace solid-phase microextraction GC-MS. Higher alcohol levels were significantly (p<0.05) higher in dark malt fermentations, while the synthesis of esters was inhibited, due to possible suppression of enzyme activity and/or gene expression linked to ester synthesis. Yeast strain also affected flavour synthesis with Saccharomyces cerevisiae strain A01 producing considerably lower levels of higher alcohols and esters than S288c and L04. S288c produced approximately double the higher alcohol levels and around twenty times more esters compared to L04. Further investigations into malt type-yeast strain interactions in relation to flavour development are required to gain better understanding of flavour synthesis that could assist in the development of new products and reduce R&D costs for the industry. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Lactic acid production by Lactobacillus sp. RKY2 in a cell-recycle continuous fermentation using lignocellulosic hydrolyzates as inexpensive raw materials.

    Science.gov (United States)

    Wee, Young-Jung; Ryu, Hwa-Won

    2009-09-01

    Continuous lactic acid fermentations were conducted using lignocellulosic hydrolyzates and corn steep liquor as inexpensive raw materials. Lactic acid concentrations decreased with increases in the dilution rate, whereas the residual substrate concentrations increased. However, lactic acid yields were maintained at more than 0.90 g g(-1) over all cases experimented. The cell-recycle cultivation system exerted positive effects on fermentation efficiency, including volumetric productivity, which is attributable to the retention of cells in the bioreactor. The cell-recycle continuous fermentation of lignocellulosic hydrolyzates yielded a lactic acid productivity of 6.7 g l(-1) h(-1) for a dilution rate of 0.16 h(-1) using 30 g l(-1) of corn steep liquor and 1.5 g l(-1) of yeast extract as nutrients. The productivity (6.7 g l(-1) h(-1)) acquired by the cell-recycle continuous fermentation of lignocellulosic hydrolyzates was 1.6 times higher than the lactic acid productivity yielded in the continuous fermentation without cell-recycle system.

  15. Response of the rumen archaeal and bacterial populations to anti-methanogenic organosulphur compounds in continuous-culture fermenters.

    Science.gov (United States)

    Martínez-Fernández, Gonzalo; Abecia, Leticia; Martín-García, A Ignacio; Ramos-Morales, Eva; Denman, Stuart E; Newbold, Charles J; Molina-Alcaide, Eduarda; Yáñez-Ruiz, David R

    2015-08-01

    Study of the efficacy of methanogenesis inhibitors in the rumen has given inconsistent results, mainly due to poorly understood effects on the key microbial groups involved in pathways for methane (CH4) synthesis. The experiment described in this report was designed to assess the effect of propyl propane thiosulfinate (PTS), diallyl disulfide (DDS) and bromochloromethane (BCM) on rumen fermentation, methane production and microbial populations in continuous culture fermenters. No effects on total volatile fatty acids (VFA) were observed with PTS or DDS, but VFA were decreased with BCM. Amylase activity increased with BCM as compared with the other treatments. A decrease in methane production was observed with PTS (48%) and BCM (94%) as compared with control values. The concentration of methanogenic archaea decreased with BCM from day 4 onward and with PTS on days 4 and 8. Pyrosequencing analysis revealed that PTS and BCM decreased the relative abundance of Methanomicrobiales and increased that of Methanobrevibacter and Methanosphaera. The total concentration of bacteria was not modified by any treatment, although treatment with BCM increased the relative abundance of Prevotella and decreased that of Ruminococcus. These results suggest that the inhibition of methane production in the rumen by PTS and BCM is associated with a shift in archaeal biodiversity and changes in the bacterial community with BCM.

  16. Effects of pH and ORP on microbial ecology and kinetics for hydrogen production in continuously dark fermentation.

    Science.gov (United States)

    Song, Jiaxiu; An, Dong; Ren, Nanqi; Zhang, Yongming; Chen, Ying

    2011-12-01

    The microbial structure and kinetic characteristics of the hydrogen producing strains in two fermentative continuous stirred-tank reactors (CSTRs) were studied by controlling pH and oxidation and reduction potential (ORP). The fluorescence in situ hybridization (FISH) tests were conducted to investigate the fermentative performance of Clostridium histolyticum (C. histolyticum), Clostridium lituseburense (C. lituseburense) and Enterobacteriaceae. The experimental results showed that in ethanol-type reactor 1#, the relative abundance of the strains was 48%, 30% and 22%. Comparatively, the relative abundance in butyric acid-type reactor 2# was 24%, 55% and 19% with butyric acids and hydrogen as the main products. The kinetic results indicated that the hydrogen yield coefficients YP/X in both reactors were 8.357 and 5.951 l-H2/g, while the coefficients of the cellular yield were 0.0268 and 0.0350 g-Cell/g, respectively. At the same biomass, the hydrogen yield in ethanol-type reactors was more than that in butyric acid reactors. However, the cellular synthesis rate in ethanol-type reactors was low when the same carbon source was used.

  17. Batch and continuous culture-based selection strategies for acetic acid tolerance in xylose-fermenting Saccharomyces cerevisiae.

    Science.gov (United States)

    Wright, Jeremiah; Bellissimi, Eleonora; de Hulster, Erik; Wagner, Andreas; Pronk, Jack T; van Maris, Antonius J A

    2011-05-01

    Acetic acid tolerance of Saccharomyces cerevisiae is crucial for the production of bioethanol and other bulk chemicals from lignocellulosic plant-biomass hydrolysates, especially at a low pH. This study explores two evolutionary engineering strategies for the improvement of acetic acid tolerance of the xylose-fermenting S. cerevisiae RWB218, whose anaerobic growth on xylose at pH 4 is inhibited at acetic acid concentrations >1 g L(-1) : (1) sequential anaerobic, batch cultivation (pH 4) at increasing acetic acid concentrations and (2) prolonged anaerobic continuous cultivation without pH control, in which acidification by ammonium assimilation generates selective pressure for acetic acid tolerance. After c. 400 generations, the sequential-batch and continuous selection cultures grew on xylose at pH≤4 with 6 and 5 g L(-1) acetic acid, respectively. In the continuous cultures, the specific xylose-consumption rate had increased by 75% to 1.7 g xylose g(-1) biomass h(-1) . After storage of samples from both selection experiments at -80 °C and cultivation without acetic acid, they failed to grow on xylose at pH 4 in the presence of 5 g L(-1) acetic acid. Characterization in chemostat cultures with linear acetic acid gradients demonstrated an acetate-inducible acetic acid tolerance in samples from the continuous selection protocol.

  18. Impaired response inhibition in the rat 5 choice continuous performance task during protracted abstinence from chronic alcohol consumption.

    Directory of Open Access Journals (Sweden)

    Cristina Irimia

    Full Text Available Impaired cognitive processing is a hallmark of addiction. In particular, deficits in inhibitory control can propel continued drug use despite adverse consequences. Clinical evidence shows that detoxified alcoholics exhibit poor inhibitory control in the Continuous Performance Task (CPT and related tests of motor impulsivity. Animal models may provide important insight into the neural mechanisms underlying this consequence of chronic alcohol exposure though pre-clinical investigations of behavioral inhibition during alcohol abstinence are sparse. The present study employed the rat 5 Choice-Continuous Performance Task (5C-CPT, a novel pre-clinical variant of the CPT, to evaluate attentional capacity and impulse control over the course of protracted abstinence from chronic intermittent alcohol consumption. In tests conducted with familiar 5C-CPT conditions EtOH-exposed rats exhibited impaired attentional capacity during the first hours of abstinence and impaired behavioral restraint (increased false alarms during the first 5d of abstinence that dissipated thereafter. Subsequent tests employing visual distractors that increase the cognitive load of the task revealed significant increases in impulsive action (premature responses at 3 and 5 weeks of abstinence, and the emergence of impaired behavioral restraint (increased false alarms at 7 weeks of abstinence. Collectively, these findings demonstrate the emergence of increased impulsive action in alcohol-dependent rats during protracted alcohol abstinence and suggest the 5C-CPT with visual distractors may provide a viable behavioral platform for characterizing the neurobiological substrates underlying impaired behavioral inhibition resulting from chronic intermittent alcohol exposure.

  19. Continuous lactose fermentation by Clostridium acetobutylicum--assessment of energetics and product yields of the acidogenesis.

    Science.gov (United States)

    Napoli, Fabio; Olivieri, Giuseppe; Russo, Maria Elena; Marzocchella, Antonio; Salatino, Piero

    2012-03-10

    An assessment of both the growth and the metabolism of acidogenic cells Clostridium acetobutylicum DSM 792 is reported in the paper. Tests were carried out in a CSTR under controlled pH conditions. Cultures were carried out using a semi-synthetic medium supplemented with lactose as carbon source. Acids and solvents, that represent products of the ABE process, have been purposely added in controlled amounts to the culture medium to investigate their effects on the product yields. The mass fractional yield of biomass and products were expressed as a function of the specific growth rate taking into account the Pirt model. The maximum ATP yield and the maintenance resulted 29.1 g(DM)/mol(ATP) and 0.012 mol(ATP)/g(DM)h, respectively. Quantitative features of the C. acetobutylicum growth model were in good agreement with experimental results. The model proposes as a tool to estimate the mass fractional yield even for fermentations carried out under conditions typical of the solventogenesis. Copyright © 2011 Elsevier Inc. All rights reserved.

  20. Simultaneous production and separation of biohydrogen in mixed culture systems by continuous dark fermentation.

    Science.gov (United States)

    Ramírez-Morales, Juan E; Tapia-Venegas, Estela; Toledo-Alarcón, Javiera; Ruiz-Filippi, Gonzalo

    2015-01-01

    Hydrogen production by dark fermentation is one promising technology. However, there are challenges in improving the performance and efficiency of the process. The important factors that must be considered to obtain a suitable process are the source of the inoculum and its pre-treatment, types of substrates, the reactor configurations and the hydrogen partial pressure. Furthermore, to obtain high-quality hydrogen, it is necessary to integrate an effective separation procedure that is compatible with the intrinsic characteristics of a biological process. Recent studies have suggested that a stable and robust process could be established if there was an effective selection of a mixed microbial consortium with metabolic pathways directly targeted to high hydrogen yields. Additionally, the integration of membrane technology for the extraction and separation of the hydrogen produced has advantages for the upgrading step, because this technology could play an important role in reducing the negative effect of the hydrogen partial pressure. Using this technology, it has been possible to implement a production-purification system, the 'hydrogen-extractive membrane bioreactor'. This configuration has great potential for direct applications, such as fuel cells, but studies of new membrane materials, module designs and reactor configurations are required to achieve higher separation efficiencies.

  1. Growth model and metabolic activity of brewing yeast biofilm on the surface of spent grains : a biocatalyst for continuous beer fermentation

    OpenAIRE

    Brányik, Tomáš; A.A. Vicente; Kuncová, Gabriela; Podrazký, Ondřej; Dostálek, Pavel; Teixeira, J. A

    2004-01-01

    In the continuous systems, such as continuous beer fermentation, immobilized cells are kept inside the bioreactor for long periods of time. Thus an important factor in the design and performance of the immobilized yeast reactor is immobilized cell viability and physiology. Both the decreasing specific glucose consumption rate (Q_im) and intracellular redox potential of the cells immobilized to spent grains during continuous cultivation in bubble-column reactor implied alteratio...

  2. Switchgrass (Panicum virgatum fermentation by Clostridium thermocellum and Clostridium saccharoperbutylacetonicum sequential culture in a continuous flow reactor

    Directory of Open Access Journals (Sweden)

    Noelia M. Elía

    2016-01-01

    Full Text Available The study was conducted to evaluate fermentation by Clostridium thermocellum and C. saccharoperbutylacetonicum in a continuous-flow, high-solids reactor. Liquid medium was continuously flowed through switchgrass (2 mm particle size at one of three flow rates: 83.33 mL h−1 (2 L d−1, 41.66 mL h−1 (1 L d−1, and 20.833 mL h−1 (0.5 L d−1. The cellulolytic phase was initiated by culturing C. thermocellum (63 °C, 24 h. The temperature was decreased (35 and C. saccharoperbutylacetonicum was inoculated. When metabolism decreased (96 h, the temperature was increased (63 °C; 24 h to permit cellulosome production by C. thermocellum. The C. saccharoperbutylacetonicum was re-inoculated and the temperature returned to 35°C. The average gross production over 9 d was 1480 mg total acids (formic, acetic lactic butyric, 207 mg total solvents (acetone, butanol, ethanol, and average dry matter disappearance was 2.8 g from 25 g non-pretreated switchgrass. There was no effect of flow rate on the product formation. These results indicate that C. thermocellum can survive and produce cellulases with C. saccharoperbutylacetonicumin a continuous-flow, high-solids reactor temperature with temperature cycling.

  3. Effects of Partial Replacement of Corn with Glycerin on Ruminal Fermentation in a Dual-Flow Continuous Culture System.

    Directory of Open Access Journals (Sweden)

    Pedro Del Bianco Benedeti

    Full Text Available The objective of this study was to evaluate the effects of partially replacing dry ground corn with glycerin on ruminal fermentation using a dual-flow continuous culture system. Six fermenters (1,223 ± 21 ml were used in a replicated 3x3 Latin square arrangement with three periods of 10 d each, with 7 d for diet adaptation and 3 d for sample collections. All diets contained 75% concentrate and three dietary glycerin levels (0, 15, and 30% on dry matter basis, totaling six replicates per treatment. Fermenters were fed 72 g of dry matter/d equally divided in two meals/d, at 0800 and 2000 h. Solid and liquid dilution rates were adjusted daily to 5.5 and 11%/h, respectively. On d 8, 9, and 10, samples of 500 ml of solid and liquid digesta effluent were mixed, homogenized, and stored at -20°C. Subsamples of 10 ml were collected and preserved with 0.2 mL of a 50% H2SO4 solution for later determination of NH3-N and volatile fatty acids. Microbial biomass was isolated from fermenters for chemical analysis at the end of each experimental period. Data were analyzed using the MIXED procedure in SAS with α = 0.05. Glycerin levels did not affect apparent digestibility of DM (PLin. = 0.13; PQuad. = 0.40, OM (PLin. = 0.72; PQuad. = 0.15, NDF (PLin. = 0.38; PQuad. = 0.50 and ADF (PLin. = 0.91; PQuad. = 0.18. Also, glycerin inclusion did not affect true digestibility of DM (PLin. = 0.35; PQuad. = 0.48, and OM (PLin. = 0.08; PQuad. = 0.19. Concentrations of propionate (P < 0.01 and total volatile fatty acids (P < 0.01 increased linearly and concentrations of acetate (P < 0.01, butyrate (P = 0.01, iso-valerate (P < 0.01, and total branched-chain volatile fatty acids, as well as the acetate: propionate ratio (P < 0.01 decreased with glycerin inclusion. Linear increases on NH3-N concentration in digesta effluent (P < 0.01 and on NH3-N flow (P < 0.01 were observed due to glycerin inclusion in the diets. Crude protein digestibility (P = 0.04 and microbial N flow (P

  4. Environmental potential of the use of CO2 from alcoholic fermentation processes. The CO2-AFP strategy.

    Science.gov (United States)

    Alonso-Moreno, Carlos; García-Yuste, Santiago

    2016-10-15

    A novel Carbon Dioxide Utilization (CDU) approach from a relatively minor CO2 emission source, i.e., alcoholic fermentation processes (AFP), is presented. The CO2 produced as a by-product from the AFP is estimated by examining the EtOH consumed per year reported by the World Health Organization in 2014. It is proposed that the extremely pure CO2 from the AFP is captured in NaOH solutions to produce one of the Top 10 commodities in the chemical industry, Na2CO3, as a good example of an atomic economy process. The novel CDU strategy could yield over 30.6Mt of Na2CO3 in oversaturated aqueous solution on using ca. 12.7Mt of captured CO2 and this process would consume less energy than the synthetic methodology (Solvay ammonia soda process) and would not produce low-value by-products. The quantity of Na2CO3 obtained by this strategy could represent ca. 50% of the world Na2CO3 production in one year. In terms of the green economy, the viability of the strategy is discussed according to the recommendations of the CO2Chem network, and an estimation of the CO2negative emission achieved suggests a capture of around 280.0Mt of CO2 from now to 2020 or ca. 1.9Gt from now to 2050. Finally, the results obtained for this new CDU proposal are discussed by considering different scenarios; the CO2 production in a typical winemaking corporation, the CO2 released in the most relevant wine-producing countries, and the use of CO2 from AFP as an alternative for the top Na2CO3-producing countries.

  5. Fuel alcohol production: effects of free amino nitrogen on fermentation of very-high-gravity wheat mashes.

    OpenAIRE

    Thomas, K C; Ingledew, W. M.

    1990-01-01

    Although wheat mashes contain only growth-limiting amounts of free amino nitrogen, fermentations by active dry yeast (Saccharomyces cerevisiae) were completed (all fermentable sugars consumed) in 8 days at 20 degrees C even when the mash contained 35 g of dissolved solids per 100 ml. Supplementing wheat mashes with yeast extract, Casamino Acids, or a single amino acid such as glutamic acid stimulated growth of the yeast and reduced the fermentation time. With 0.9% yeast extract as the supplem...

  6. 微生物发酵法生产糖醇的研究进展%Research Progress on Production of Sugar Alcohols by Microbial Fermentation

    Institute of Scientific and Technical Information of China (English)

    樊洁; 韩烨; 周志江; 赵鑫

    2013-01-01

    Sugar alcohol has attracted great interest for its low sweetness, low calorie, well-taste, stability and good-solution etc. Sugar alcohol production by microbial fermentation has gradually become a hot research area, owing to its moderate process and low energy consumption. This review summarized the research progress in the production by microbial fermentation of the common sugar alcohols sorbitol, mannitol, xylitol and erythritol.%糖醇具有甜度低、热值低、口感好、稳定性强、水溶性高、适宜人群广等特点,越来越受到消费者的欢迎。微生物发酵法过程温和,能耗低,因此利用微生物发酵法生产糖醇逐步成为研究热点。本文就用微生物发酵法生产常见糖醇-山梨醇、甘露醇、木糖醇、赤藓糖醇的研究进展进行了综述。

  7. Control of packed column fouling in the continuous fermentation and stripping of ethanol.

    Science.gov (United States)

    Taylor, F; Kurantz, M J; Goldberg, N; Craig, J C

    1996-07-05

    By recycling the contents of a 14 L fermentor through a stripping column to continuously remove ethanol and reduce product inhibition, continuous complete conversion of nutrient feed containing 600 g/L glucose was achieved in a small pilot plant. Ethanol was recovered from the carbon dioxide stripping gas in a refrigerated condenser, and the gas was reheated with steam and recycled by a blower. Productivity of ethanol in the fermentor as high as 15.8 g/L/h and condensate production of up to 10 L/day of almost 50% by volume ethanol were maintained for up to 60 days of continuous operation. Weekly washing of the column packing in situ was required to prevent loss of performance caused by attached growth of yeast cells, which restricts the gas flow rate through the stripping column. (c) 1996 John Wiley & Sons, Inc.

  8. Process Design of Continuous-Flow Pervaporation Separa tion for Alcohol Dehydration

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The separation characteristics of the PVA-CS (polyvinyl alcohol-chitosan) blended composite membrane for dehydration of ethanol-water mixture are examined. The relationships of flux and separation factor with the feed concentration and operation temperature are established. Using this correlated equation, the continuous-flow pervaporation process about 500 kilolitres/year dehydrated ethanol is designed. The numbers of stage and reheater are calculated by stage-by-stage method for two kinds of cascades: one with equal membrane area and the other with 10℃C of temperature decrement per section. The results show that when the numbers of stage and reheater are the same, the cascade with 10℃C of temperature decrement has more advantages than that with equal membrane area. The influences of feed concentration and flow rate on the numbers of stage and reheater in the cascades are discnssed.

  9. Continuous catalyst-free methanolysis and ethanolysis of soybean oil under supercritical alcohol/water mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Vieitez, Ignacio; Grompone, Maria A.; Jachmanian, Ivan [Laboratorio de Grasas y Aceites, Departamento de Alimentos, Facultad de Quimica, Universidad de la Republica, Montevideo 11800 (Uruguay); da Silva, Camila; Alckmin, Isabella; Borges, Gustavo R.; Corazza, Fernanda C.; Oliveira, J. Vladimir [Department of Food Engineering, URI-Campus de Erechim, Erechim 99700-000 (Brazil)

    2010-09-15

    This work investigates and compares the reaction performance of soybean oil transesterification under supercritical methanol and ethanol, in a continuous catalyst-free process, as a cleaner alternative to conventional chemically catalyzed process. Reactions were performed in a tubular reactor, at 20 MPa, with oil to alcohol ratio of 1:40, varying the temperature in the range from 250 C to 350 C, and at two levels of water concentrations, 0 and 10 wt%. Although both processes proceeded with a relatively high reaction rate, conversion achieved by methanolysis was higher than that obtained by ethanolysis. Water positively affected both process: higher ester content and triacylglycerols depletion occurred when 10 wt% water was used compared with anhydrous conditions. Temperature increase favored the conversion of soybean oil to the corresponding methyl or ethyl esters, although temperatures above 300 C increased the fatty acid degradation degree, a phenomenon responsible for the low ester contents obtained at the highest temperatures and lowest flow rates studied. (author)

  10. Coproduction of hydrogen and methane via anaerobic fermentation of cornstalk waste in continuous stirred tank reactor integrated with up-flow anaerobic sludge bed.

    Science.gov (United States)

    Cheng, Xi-Yu; Li, Qian; Liu, Chun-Zhao

    2012-06-01

    A 10 L continuous stirred tank reactor (CSTR) system was developed for a two-stage hydrogen fermentation process with an integrated alkaline treatment. The maximum hydrogen production rate reached 218.5 mL/L h at a cornstalk concentration of 30 g/L, and the total hydrogen yield and volumetric hydrogen production rate reached 58.0 mL/g-cornstalk and 0.55-0.57 L/L d, respectively. A 10 L up-flow anaerobic sludge bed (UASB) was used for continuous methane fermentation of the effluents obtained from the two-stage hydrogen fermentation. At the optimal organic loading rate of 15.0 g-COD/Ld, the COD removal efficiency and volumetric biogas production rate reached 83.3% and 4.6L/Ld, respectively. Total methane yield reached 200.9 mL/g-cornstalk in anaerobic fermentation with the effluents and alkaline hydrolysate. As a result, the total energy recovery by coproduction of hydrogen and methane with anaerobic fermentation of cornstalk reached 67.1%.

  11. 皂素废水酒精发酵条件的研究%Study on the Alcohol Fermentation Conditions from Diosgenin Wastewater

    Institute of Scientific and Technical Information of China (English)

    耿海波; 安丽平

    2011-01-01

    The batch wastewater,which was the most polluted and consisted of the highest organic matter concentration,was used to produce industrial alcohol.The optimum technological parameters of fermentation process were found out.%利用皂素废水中有机物含量最高、污染最重的一次废水,发酵生产工业酒精。确定了皂素废水酒精发酵的最佳工艺条件。

  12. Inhibitory Role of Greatwall-Like Protein Kinase Rim15p in Alcoholic Fermentation via Upregulating the UDP-Glucose Synthesis Pathway in Saccharomyces cerevisiae.

    Science.gov (United States)

    Watanabe, Daisuke; Zhou, Yan; Hirata, Aiko; Sugimoto, Yukiko; Takagi, Kenichi; Akao, Takeshi; Ohya, Yoshikazu; Takagi, Hiroshi; Shimoi, Hitoshi

    2015-10-23

    The high fermentation rate of Saccharomyces cerevisiae sake yeast strains is attributable to a loss-of-function mutation in the RIM15 gene, which encodes a Greatwall-family protein kinase that is conserved among eukaryotes. In the present study, we performed intracellular metabolic profiling analysis and revealed that deletion of the RIM15 gene in a laboratory strain impaired glucose-anabolic pathways through the synthesis of UDP-glucose (UDPG). Although Rim15p is required for the synthesis of trehalose and glycogen from UDPG upon entry of cells into the quiescent state, we found that Rim15p is also essential for the accumulation of cell wall β-glucans, which are also anabolic products of UDPG. Furthermore, the impairment of UDPG or 1,3-β-glucan synthesis contributed to an increase in the fermentation rate. Transcriptional induction of PGM2 (phosphoglucomutase) and UGP1 (UDPG pyrophosphorylase) was impaired in Rim15p-deficient cells in the early stage of fermentation. These findings demonstrate that the decreased anabolism of glucose into UDPG and 1,3-β-glucan triggered by a defect in the Rim15p-mediated upregulation of PGM2 and UGP1 redirects the glucose flux into glycolysis. Consistent with this, sake yeast strains with defective Rim15p exhibited impaired expression of PGM2 and UGP1 and decreased levels of β-glucans, trehalose, and glycogen during sake fermentation. We also identified a sake yeast-specific mutation in the glycogen synthesis-associated glycogenin gene GLG2, supporting the conclusion that the glucose-anabolic pathway is impaired in sake yeast. These findings demonstrate that downregulation of the UDPG synthesis pathway is a key mechanism accelerating alcoholic fermentation in industrially utilized S. cerevisiae sake strains.

  13. Optimization of a low-cost defined medium for alcoholic fermentation--a case study for potential application in bioethanol production from industrial wastewaters.

    Science.gov (United States)

    Comelli, Raúl N; Seluy, Lisandro G; Isla, Miguel A

    2016-01-25

    In bioethanol production processes, the media composition has an impact on product concentration, yields and the overall process economics. The main purpose of this research was to develop a low-cost mineral-based supplement for successful alcoholic fermentation in an attempt to provide an economically feasible alternative to produce bioethanol from novel sources, for example, sugary industrial wastewaters. Statistical experimental designs were used to select essential nutrients for yeast fermentation, and its optimal concentrations were estimated by Response Surface Methodology. Fermentations were performed on synthetic media inoculated with 2.0 g L(-1) of yeast, and the evolution of biomass, sugar, ethanol, CO2 and glycerol were monitored over time. A mix of salts [10.6 g L(-1) (NH4)2HPO4; 6.4 g L(-1) MgSO4·7H2O and 7.5 mg L(-1) ZnSO4·7H2O] was found to be optimal. It led to the complete fermentation of the sugars in less than 12h with an average ethanol yield of 0.42 g ethanol/g sugar. A general C-balance indicated that no carbonaceous compounds different from biomass, ethanol, CO2 or glycerol were produced in significant amounts in the fermentation process. Similar results were obtained when soft drink wastewaters were tested to evaluate the potential industrial application of this supplement. The ethanol yields were very close to those obtained when yeast extract was used as the supplement, but the optimized mineral-based medium is six times cheaper, which favorably impacts the process economics and makes this supplement more attractive from an industrial viewpoint.

  14. Engineering of xylose reductase and overexpression of xylitol dehydrogenase and xylulokinase improves xylose alcoholic fermentation in the thermotolerant yeast Hansenula polymorpha

    Directory of Open Access Journals (Sweden)

    Voronovsky Andriy Y

    2008-07-01

    Full Text Available Abstract Background The thermotolerant methylotrophic yeast Hansenula polymorpha is capable of alcoholic fermentation of xylose at elevated temperatures (45 – 48°C. Such property of this yeast defines it as a good candidate for the development of an efficient process for simultaneous saccharification and fermentation. However, to be economically viable, the main characteristics of xylose fermentation of H. polymorpha have to be improved. Results Site-specific mutagenesis of H. polymorpha XYL1 gene encoding xylose reductase was carried out to decrease affinity of this enzyme toward NADPH. The modified version of XYL1 gene under control of the strong constitutive HpGAP promoter was overexpressed on a Δxyl1 background. This resulted in significant increase in the KM for NADPH in the mutated xylose reductase (K341 → R N343 → D, while KM for NADH remained nearly unchanged. The recombinant H. polymorpha strain overexpressing the mutated enzyme together with native xylitol dehydrogenase and xylulokinase on Δxyl1 background was constructed. Xylose consumption, ethanol and xylitol production by the constructed strain were determined for high-temperature xylose fermentation at 48°C. A significant increase in ethanol productivity (up to 7.3 times was shown in this recombinant strain as compared with the wild type strain. Moreover, the xylitol production by the recombinant strain was reduced considerably to 0.9 mg × (L × h-1 as compared to 4.2 mg × (L × h-1 for the wild type strain. Conclusion Recombinant strains of H. polymorpha engineered for improved xylose utilization are described in the present work. These strains show a significant increase in ethanol productivity with simultaneous reduction in the production of xylitol during high-temperature xylose fermentation.

  15. Continuous lactose fermentation by Clostridium acetobutylicum--assessment of solventogenic kinetics.

    Science.gov (United States)

    Procentese, Alessandra; Raganati, Francesca; Olivieri, Giuseppe; Russo, Maria Elena; Salatino, Piero; Marzocchella, Antonio

    2015-03-01

    This work reports the results of a series of tests on the specific butanol production rate by Clostridium acetobutylicum continuous cultures. The tests were carried out using lactose as carbon source to mimic cheese-whey. A continuous stirred tank reactor equipped with a microfiltration unit was used. The dilution rate (D) ranged between 0.02 and 0.15h(-1) and the ratio R of the permeate stream rate to the stream fed to the reactor ranged between 14% and 95%. For each set of D and R values, the continuous cultures were characterized in terms of concentration of cells, acids and solvents. Results were processed to assess the concentration of acidogenic cells, solventogenic cells, spores and the specific butanol production rate. The max butanol productivity was 0.5gL(-1)h(-1) at D=0.1h(-1) and R=95%. The butanol productivity referred to solventogenic cells was expressed as a function of concentration of lactose, acids and butanol. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. 餐厨垃圾厌氧发酵制氢残留物连续沼气发酵研究%Research on Continuous Methane Fermentation of Residues of Hydrogen Production by Anaerobic Fermentation of Kitchen Waste

    Institute of Scientific and Technical Information of China (English)

    张国华; 张志红; 黄江丽; 王东升; 丁建南

    2015-01-01

    餐厨垃圾中有机物含量高,利用餐厨垃圾厌氧发酵制备氢气后残留物中含有丰富的低级脂肪酸、醇类等. 从接种产甲烷菌和pH调节角度,利用餐厨垃圾厌氧发酵制备氢气后的残留物研究连续沼气发酵,提高餐厨垃圾资源利用率. 结果表明,在接种产甲烷菌和调节发酵体系pH>7的条件下,餐厨垃圾厌氧发酵制备氢气后的残留物能够连续沼气发酵. 接种以新鲜沼渣为产甲烷菌来源的沼气发酵比以厌氧活性污泥为产甲烷菌种来源的沼气发酵产气效果好.%Kitchen waste contents high organic matter, and abundant of low-level fatty acids, alco-hols,etc. exist in the residues after using kitchen waste preparation for hydrogen by anaerobic fer-mentation. This paper studied the feasibility of continue to produce methane by anaerobic fermenta-tion of hydrogen production residues from inoculate methane bacteria and pH,which hope to improve the utilization of kitchen waste resources. The results show that, under the conditions of pH>7 and inoculated methane bacteria in the anaerobic fermentation system,it can continue to produce methane use the hydrogen production residues by anaerobic fermentation,and it is better of produce biogas by inoculated with fresh biogas residues as methane bacteria in anaerobic fermentation than inoculated with anaerobic activated sludge as methane bacteria.

  17. Continuous lactose fermentation by Clostridium acetobutylicum--assessment of acidogenesis kinetics.

    Science.gov (United States)

    Napoli, Fabio; Olivieri, Giuseppe; Russo, Maria Elena; Marzocchella, Antonio; Salatino, Piero

    2011-01-01

    An assessment of the growth kinetics of acidogenic cells of Clostridium acetobutylicum DSM 792 is reported in the paper. Tests were carried out in a continuous stirred tank reactor under controlled conditions adopting a complex medium supplemented with lactose as carbon source to mimic cheese whey. The effects of acids (acetic and butyric), solvents (acetone, ethanol and butanol) and pH on the growth rate of acidogenic cells were assessed. The conversion process was characterized under steady-state conditions in terms of concentration of lactose, cells, acids, total organic carbon and pH. The growth kinetics was expressed by means of a multiple product inhibition and interacting model including a novel formulation to account for the role of pH. The model has the potential to predict microorganism growth rate under a broad interval of operating conditions, even those typical of solvents production. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Esterification of Fatty Acids with Short-Chain Alcohols over Commercial Acid Clays in a Semi-Continuous Reactor

    Directory of Open Access Journals (Sweden)

    Mohamed H. Frikha

    2009-11-01

    Full Text Available Production of fatty acid esters from stearic, oleic, and palmitic acids and short-chain alcohols (methanol, ethanol, propanol, and butanol for the production of biodiesel was investigated in this work. A series of montmorillonite-based clays catalysts (KSF, KSF/0, KP10, and K10 were used as acidic catalysts. The influence of the specific surface area and the acidity of the catalysts on the esterification rate were investigated. The best catalytic activities were obtained with KSF/0 catalyst. The esterification reaction has been carried out efficiently in a semi-continuous reactor at 150°C temperature higher than the boiling points of water and alcohol. The reactor used enabled the continuous removal of water and esterification with hydrated alcohol (ethanol 95% without affecting the original activity of the clay.

  19. Effects of initial pH value of the medium on the alcoholic fermentation performance of Saccharomyces cerevisiae cells immobilized on nipa leaf sheath pieces

    Directory of Open Access Journals (Sweden)

    Hoang Duc Toan Le

    2014-12-01

    Full Text Available Immobilized yeast on nipa leaf sheath pieces was applied to ethanol fermentation using the medium with different initial pH values (5.1, 4.5, 4.0, and 3.5. Control samples with the free yeast were also carried out under the same conditions. Low pH value of 4.0 or 3.5 significantly reduced yeast growth and increased the residual sugar level in the fermentation broths for both the immobilized and free cells. In all cases, the ethanol content produced and ethanol formation rate of the immobilized yeast were 13-33% and 35-69%, respectively, higher than those of the free yeast. In addition, the residual sugar content in the immobilized yeast cultures was 2.1-20.5 times lower than that in the free yeast cultures. The yeast immobilized on nipa leaf stem pieces exhibited higher alcoholic fermentation performance than the free yeast in medium with low pH value. This support was potential for further research for application in ethanol industry.

  20. Optimal control of hydrogen production in a continuous anaerobic fermentation bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Aceves-Lara, Cesar-Arturo [INRA, UMR792, Ingenierie des Systemes Biologiques et des Procedes, Toulouse (France); CNRS, UMR5504, Toulouse, France 135 Avenue de Rangueil, Toulouse Cedex F-31077 (France); INRA, UR050, Laboratoire de Biotechnologie de l' Environnement, Avenue des Etangs, Narbonne F-11100 (France); Latrille, Eric; Steyer, Jean-Philippe [INRA, UR050, Laboratoire de Biotechnologie de l' Environnement, Avenue des Etangs, Narbonne F-11100 (France)

    2010-10-15

    This paper addresses the problem of optimization of hydrogen production in continuous anaerobic digesters using a model predictive control (MPC) strategy. The process is described by a dynamic nonlinear model. The influent concentration of molasses together with the effluent substrate and product concentrations of acetate, propionate, butyrate and biomass were estimated by an asymptotic online observer from measurements of gas composition in H{sub 2} and CO{sub 2} and gas flow rate. The observer was tested experimentally before to apply MPC online. The combined strategy (MPC and observer) was used in order to optimize a bioreactor of 2 L. The hydrogen production was increased by 75% up to 8.27mL{sub H{sub 2}} L{sup -1}min{sup -1}, using the influent flow rate as the main control variable while keeping the conversion of the influent concentration higher than 95% and maintaining the temperature at 37 C and pH at 5.5. (author)

  1. Fermentation of glucose by Zymomonas mobilis CP4 utilising continuous transient technique

    Directory of Open Access Journals (Sweden)

    João Batista Buzato

    2003-01-01

    Full Text Available Ethanol production by Zymomonas mobilis CP4 under continuous transient operation has been investigated. The bacteria was grown under alternating glucose amplitudes of 2% and 5% (w/p and cycle time values of 2, 4 and 6 hours. The ethanol production was compared to data obtained in simple chemostat operation grown 3.5%(w/v glucose medium. The value of dilution rate was fixed as 0.2h-1 for both techniques. When cycle time value of 2 hours was used, values of biomass and ethanol kept constant. The appliance of cycle time of 4 hours produced smooth responses from the organisms. The values of biomass oscillated from 0.7 to 0.93 g/l. When cycle time of 6 hours was used the oscillations on biomass and ethanol were pronounced. The minimum and maximum values of biomass were respectively 0.61 and 1g/l. As far as conversion efficiency to ethanol is concerned the values of 84, 85 and 89% (corresponding to cycle time of 2, 4 and 6 hours were found whereas conversion efficiency was low as 50% when simple chemostat was used.

  2. Volatile fingerprints of seeds of four species indicate the involvement of alcoholic fermentation, lipid peroxidation, and Maillard reactions in seed deterioration during ageing and desiccation stress.

    Science.gov (United States)

    Colville, Louise; Bradley, Emma L; Lloyd, Antony S; Pritchard, Hugh W; Castle, Laurence; Kranner, Ilse

    2012-11-01

    The volatile compounds released by orthodox (desiccation-tolerant) seeds during ageing can be analysed using gas chromatography-mass spectrometry (GC-MS). Comparison of three legume species (Pisum sativum, Lathyrus pratensis, and Cytisus scoparius) during artificial ageing at 60% relative humidity and 50 °C revealed variation in the seed volatile fingerprint between species, although in all species the overall volatile concentration increased with storage period, and changes could be detected prior to the onset of viability loss. The volatile compounds are proposed to derive from three main sources: alcoholic fermentation, lipid peroxidation, and Maillard reactions. Lipid peroxidation was confirmed in P. sativum seeds through analysis of malondialdehyde and 4-hydroxynonenal. Volatile production by ageing orthodox seeds was compared with that of recalcitrant (desiccation-sensitive) seeds of Quercus robur during desiccation. Many of the volatiles were common to both ageing orthodox seeds and desiccating recalcitrant seeds, with alcoholic fermentation forming the major source of volatiles. Finally, comparison was made between two methods of analysis; the first used a Tenax adsorbent to trap volatiles, whilst the second used solid phase microextraction to extract volatiles from the headspace of vials containing powdered seeds. Solid phase microextraction was found to be more sensitive, detecting a far greater number of compounds. Seed volatile analysis provides a non-invasive means of characterizing the processes involved in seed deterioration, and potentially identifying volatile marker compounds for the diagnosis of seed viability loss.

  3. 固定化连续发酵研究及应用进展%Advance in the Research on and the Application of the Continuous Fermentation with Immobilized Technology

    Institute of Scientific and Technical Information of China (English)

    贾淑丽; 侯红萍

    2012-01-01

    Immobilized continuous fermentation refers to the placement of immobilized cells or immobilized enzyme in certain bioreactor for continuous fermentation.In this paper,the research progress in bioreactor,fermenting technology,and dynamics for immobilized continuous fermentation were elaborated,and the application of immobilized continuous fermentation in different fields was also introduced.%固定化连续发酵是将固定化细胞或固定化酶置于某一生物反应器内进行连续发酵的技术。阐述了固定化连续发酵生物反应器、发酵工艺及动力学的研究,并介绍了该技术在各个领域的应用进展。

  4. A Randomized Trial of Extended Telephone-Based Continuing Care for Alcohol Dependence: Within-Treatment Substance Use Outcomes

    Science.gov (United States)

    McKay, James R.; Van Horn, Deborah H. A.; Oslin, David W.; Lynch, Kevin G.; Ivey, Megan; Ward, Kathleen; Drapkin, Michelle L.; Becher, Julie R.; Coviello, Donna M.

    2010-01-01

    Objective: The study tested whether adding up to 18 months of telephone continuing care, either as monitoring and feedback (TM) or longer contacts that included counseling (TMC), to intensive outpatient programs (IOPs) improved outcomes for alcohol-dependent patients. Method: Participants (N = 252) who completed 3 weeks of IOP were randomized to…

  5. Unhealthy behaviors during pregnancy : who continues to smoke and consume alcohol, and is treatment of anxiety and depressive symptoms effective?

    NARCIS (Netherlands)

    Beijers, Chantal

    2014-01-01

    This thesis investigated continued smoking and alcohol consumption during pregnancy, and treatment of anxiety and depressive symptoms during pregnancy using cognitive behavioral therapy. Data from a large prospective population-based cohort study and a randomized controlled trial were used. Regardin

  6. Alcohol

    NARCIS (Netherlands)

    Hendriks, H.F.; Tol, A. van

    2005-01-01

    Alcohol consumption affects overall mortality. Light to moderate alcohol consumption reduces the risk of coronary heart disease; epidemiological, physiological and genetic data show a causal relationship. Light to moderate drinking is also associated with a reduced risk of other vascular diseases an

  7. Improvement on the productivity of continuous tequila fermentation by Saccharomyces cerevisiae of Agave tequilana juice with supplementation of yeast extract and aeration.

    Science.gov (United States)

    Hernández-Cortés, Guillermo; Valle-Rodríguez, Juan Octavio; Herrera-López, Enrique J; Díaz-Montaño, Dulce María; González-García, Yolanda; Escalona-Buendía, Héctor B; Córdova, Jesús

    2016-12-01

    Agave (Agave tequilana Weber var. azul) fermentations are traditionally carried out employing batch systems in the process of tequila manufacturing; nevertheless, continuous cultures could be an attractive technological alternative to increase productivity and efficiency of sugar to ethanol conversion. However, agave juice (used as a culture medium) has nutritional deficiencies that limit the implementation of yeast continuous fermentations, resulting in high residual sugars and low fermentative rates. In this work, fermentations of agave juice using Saccharomyces cerevisiae were put into operation to prove the necessity of supplementing yeast extract, in order to alleviate nutritional deficiencies of agave juice. Furthermore, continuous fermentations were performed at two different aeration flow rates, and feeding sterilized and non-sterilized media. The obtained fermented musts were subsequently distilled to obtain tequila and the preference level was compared against two commercial tequilas, according to a sensorial analysis. The supplementation of agave juice with air and yeast extract augmented the fermentative capacity of S. cerevisiae S1 and the ethanol productivities, compared to those continuous fermentations non supplemented. In fact, aeration improved ethanol production from 37 to 40 g L(-1), reducing sugars consumption from 73 to 88 g L(-1) and ethanol productivity from 3.0 to 3.2 g (Lh)(-1), for non-aerated and aerated (at 0.02 vvm) cultures, respectively. Supplementation of yeast extract allowed an increase in specific growth rate and dilution rates (0.12 h(-1), compared to 0.08 h(-1) of non-supplemented cultures), ethanol production (47 g L(-1)), reducing sugars consumption (93 g L(-1)) and ethanol productivity [5.6 g (Lh)(-1)] were reached. Additionally, the effect of feeding sterilized or non-sterilized medium to the continuous cultures was compared, finding no significant differences between both types of cultures. The overall effect

  8. Investigating the effects of Salvia mirzayanii essential oil on rumen microbial fermentation and nutrient digestibility using gas production and dual flow continuous culture system

    Directory of Open Access Journals (Sweden)

    Younes Ouladshanbe

    2014-08-01

    Full Text Available This study was conducted to investigate the effects of different doses of salvia mirzayanii essential oils on gas production parameters, fermentation characteristics using gas production and dual flow continuous culture system. Trearments in the gas production experiment was adding 0, 400, 800, 1200, 1600, 2000, 2400 and 4800 mg/l of salvia mirzayanii essential oils to the media. In the second experiment, five 1750-mL dual-flow continuous culture fermenters were used in 3 replicated periods of 9 d. Temperature (38.5°C and liquid and (10%/h solid (5%/h dilution rates were kept constant in the fermenters. Fermenters were fed daily with 120 g dry matter. Treatments arranged as complete randomized block design included levels of essential oils from salvia mirzayanii (800, 1600, 2400 mg/l and a monensin (0.1 percent of the diet dry matter. Addition essential oils of salvia mirzayanii to diet lead to decrease asymptotic gas production, organic matter degradability and biomass. Dry matter digestibility and NDF with the level of 800 mg/l essential oil compered to control treatment were significantly increased. Concentration of NH3-N was less for pre-feeding (0 h in treatments with T2 and T3 compared with control treatment. The average of concentration NH3-N was lowest in highest level of essential oils eight hours after feeding. The results showed that using of low level of salvia mirzayanii essential oils could improve nutrient digestibility in the rumen.

  9. Clostridium difficile colonization and antibiotics response in PolyFermS continuous model mimicking elderly intestinal fermentation

    Directory of Open Access Journals (Sweden)

    Sophie Fehlbaum

    2016-12-01

    Full Text Available Abstract Background Clostridium difficile (CD, a spore-forming and toxin-producing bacterium, is the main cause for antibiotic-associated diarrhea in the elderly. Here we investigated CD colonization in novel in vitro fermentation models inoculated with immobilized elderly fecal microbiota and the effects of antibiotic treatments. Methods Two continuous intestinal PolyFermS models inoculated with different immobilized elder microbiota were used to investigate selected factors of colonization of CD in proximal (PC, model 1 and transverse-distal (TDC, model 1 and 2 colon conditions. Colonization of two CD strains of different PCR ribotypes, inoculated as vegetative cells (ribotype 001, model 1 or spores (ribotypes 001 and 012, model 2, was tested. Treatments with two antibiotics, ceftriaxone (daily 150 mg L−1 known to induce CD infection in vivo or metronidazole (twice daily 333 mg L−1 commonly used to treat CD, were investigated in TDC conditions (model 2 for their effects on gut microbiota composition (qPCR, 16S pyrosequencing and activity (HPLC, CD spore germination and colonization, and cytotoxin titer (Vero cell assay. Results CD remained undetected after inoculating vegetative cells in PC reactors of model 1, but was shown to colonize TDC reactors of both models, reaching copy numbers of up to log10 8 mL−1 effluent with stable production of toxin correlating with CD cell numbers. Ceftriaxone treatment in TDC reactors showed only small effects on microbiota composition and activity and did not promote CD colonization compared to antibiotic-free control reactor. In contrast, treatment with metronidazole after colonization of CD induced large modifications in the microbiota and decreased CD numbers below the detection limit of the specific qPCR. However, a fast CD recurrence was measured only 2 days after cessation of metronidazole treatment. Conclusions Using our in vitro fermentation models, we demonstrated that stable CD

  10. Altered Fermentative Metabolism in Chlamydomonas reinhardtii Mutants Lacking Pyruvate Formate Lyase and Both Pyruvate Formate Lyase and Alcohol Dehydrogenase

    Energy Technology Data Exchange (ETDEWEB)

    Catalanotti, C.; Dubini, A.; Subramanian, V.; Yang, W. Q.; Magneschi, L.; Mus, F.; Seibert, M.; Posewitz, M. C.; Grossman, A. R.

    2012-02-01

    Chlamydomonas reinhardtii, a unicellular green alga, often experiences hypoxic/anoxic soil conditions that activate fermentation metabolism. We isolated three Chlamydomonas mutants disrupted for the pyruvate formate lyase (PFL1) gene; the encoded PFL1 protein catalyzes a major fermentative pathway in wild-type Chlamydomonas cells. When the pfl1 mutants were subjected to dark fermentative conditions, they displayed an increased flux of pyruvate to lactate, elevated pyruvate decarboxylation, ethanol accumulation, diminished pyruvate oxidation by pyruvate ferredoxin oxidoreductase, and lowered H2 production. The pfl1-1 mutant also accumulated high intracellular levels of lactate, succinate, alanine, malate, and fumarate. To further probe the system, we generated a double mutant (pfl1-1 adh1) that is unable to synthesize both formate and ethanol. This strain, like the pfl1 mutants, secreted lactate, but it also exhibited a significant increase in the levels of extracellular glycerol, acetate, and intracellular reduced sugars and a decrease in dark, fermentative H2 production. Whereas wild-type Chlamydomonas fermentation primarily produces formate and ethanol, the double mutant reroutes glycolytic carbon to lactate and glycerol. Although the metabolic adjustments observed in the mutants facilitate NADH reoxidation and sustained glycolysis under dark, anoxic conditions, the observed changes could not have been predicted given our current knowledge of the regulation of fermentation metabolism.

  11. Analyzing repeated measures semi-continuous data, with application to an alcohol dependence study.

    Science.gov (United States)

    Liu, Lei; Strawderman, Robert L; Johnson, Bankole A; O'Quigley, John M

    2016-02-01

    Two-part random effects models (Olsen and Schafer,(1) Tooze et al.(2)) have been applied to repeated measures of semi-continuous data, characterized by a mixture of a substantial proportion of zero values and a skewed distribution of positive values. In the original formulation of this model, the natural logarithm of the positive values is assumed to follow a normal distribution with a constant variance parameter. In this article, we review and consider three extensions of this model, allowing the positive values to follow (a) a generalized gamma distribution, (b) a log-skew-normal distribution, and (c) a normal distribution after the Box-Cox transformation. We allow for the possibility of heteroscedasticity. Maximum likelihood estimation is shown to be conveniently implemented in SAS Proc NLMIXED. The performance of the methods is compared through applications to daily drinking records in a secondary data analysis from a randomized controlled trial of topiramate for alcohol dependence treatment. We find that all three models provide a significantly better fit than the log-normal model, and there exists strong evidence for heteroscedasticity. We also compare the three models by the likelihood ratio tests for non-nested hypotheses (Vuong(3)). The results suggest that the generalized gamma distribution provides the best fit, though no statistically significant differences are found in pairwise model comparisons.

  12. Hydrogen production by hup(-) mutant and wild-type strains of Rhodobacter capsulatus from dark fermentation effluent of sugar beet thick juice in batch and continuous photobioreactors.

    Science.gov (United States)

    Uyar, Basar; Gürgan, Muazzez; Özgür, Ebru; Gündüz, Ufuk; Yücel, Meral; Eroglu, Inci

    2015-10-01

    Photofermentative production of hydrogen is a promising and sustainable process; however, it should be coupled to dark fermentation to become cost effective. In order to integrate dark fermentation and photofermentation, the suitability of dark fermenter effluents for the photofermentative hydrogen production must be demonstrated. In this study, thermophilic dark fermenter effluent (DFE) of sugar beet thick juice was used as a substrate in photofermentation process to compare wild-type and uptake hydrogenase-deficient (hup (-)) mutant strains of Rhodobacter capsulatus by means of hydrogen production and biomass growth. The tests were conducted in small-scale (50 mL) batch and large-scale (4 L) continuous photobioreactors in indoor conditions under continuous illumination. In small scale batch conditions, maximum cell concentrations were 0.92 gdcw/L c and 1.50 gdcw/L c, hydrogen yields were 34 % and 31 %, hydrogen productivities were 0.49 mmol/(L c·h) and 0.26 mmol/(Lc·h), for hup (-) and wild-type cells, respectively. In large-scale continuous conditions, maximum cell concentrations were 1.44 gdcw/L c and 1.87 gdcw/L c, hydrogen yields were 48 and 46 %, and hydrogen productivities were 1.01 mmol/(L c·h) and 1.05 mmol/(L c·h), for hup (-) and wild-type cells, respectively. Our results showed that Rhodobacter capsulatus hup (-) cells reached to a lower maximum cell concentration but their hydrogen yield and productivity were in the same range or superior compared to the wild-type cells in both batch and continuous operating modes. The maximum biomass concentration, yield and productivity of hydrogen were higher in continuous mode compared to the batch mode with both bacterial strains.

  13. Identification of genes required for maximal tolerance to high-glucose concentrations, as those present in industrial alcoholic fermentation media, through a chemogenomics approach.

    Science.gov (United States)

    Teixeira, Miguel C; Raposo, Luís R; Palma, Margarida; Sá-Correia, Isabel

    2010-04-01

    Chemogenomics, the study of genomic responses to chemical compounds, has the potential to elucidate the basis of cellular resistance to those chemicals. This knowledge can be applied to improve the performance of strains of industrial interest. In this study, a collection of approximately 5,000 haploid single deletion mutants of Saccharomyces cerevisiae in which each nonessential yeast gene was individually deleted, was screened for strains with increased susceptibility toward stress induced by high-glucose concentration (30% w/v), one of the main stresses occurring during industrial alcoholic fermentation processes aiming the production of alcoholic beverages or bio-ethanol. Forty-four determinants of resistance to high-glucose stress were identified. The most significant Gene Ontology (GO) terms enriched in this dataset are vacuolar organization, late endosome to vacuole transport, and regulation of transcription. Clustering the identified resistance determinants by their known physical and genetic interactions further highlighted the importance of nutrient metabolism control in this context. A concentration of 30% (w/v) of glucose was found to perturb vacuolar function, by reducing cell ability to maintain the physiological acidification of the vacuolar lumen. This stress also affects the active rate of proton efflux through the plasma membrane. Based on results of published studies, the present work revealed shared determinants of yeast resistance to high-glucose and ethanol stresses, including genes involved in vacuolar function, cell wall biogenesis (ANP1), and in the transcriptional control of nutrient metabolism (GCN4 and GCR1), with possible impact on the design of more robust strains to be used in industrial alcoholic fermentation processes.

  14. Frontal lobe dysfunctions in Korsakoff's syndrome and chronic alcoholism: Continuity or discontinuity?

    NARCIS (Netherlands)

    Brokate, B.; Hildebrandt, H.; Eling, P.A.T.M.; Fichtner, H.; Runge, K.; Timm, C.

    2003-01-01

    The effect of long-term heavy alcohol consumption on brain functions is still under debate. The authors investigated a sample of 17 Korsakoff amnesics, 23 alcoholics without Korsakoff's syndrome, and 21 controls with peripheral nerve diseases, matched for intelligence and education. Executive functi

  15. Alcohol

    Science.gov (United States)

    ... changes that come from drinking alcohol can make people do stupid or embarrassing things, like throwing up or peeing on themselves. Drinking also gives people bad breath, and no one enjoys a hangover. ...

  16. Effect of fermenting material concentration on biogas yield in batch and continuous biogas fermentation with straws%秸秆批式和半连续式发酵物料浓度对沼气产率的影响

    Institute of Scientific and Technical Information of China (English)

    杜静; 陈广银; 黄红英; 靳红梅; 奚永兰; 钱玉婷; 徐跃定; 常志州

    2015-01-01

    At present, large quantities of straws are burned in field in China, which not only wastes a renewable resource, but also causes serious air pollution. Anaerobic digestion of straws is an alternative method that may produce a clean fuel for energy generation. Currently, more research on impact of digestion for quality content of total solid of manure or mixed materials for the fermentation substrate has been studied, but research is limited in continuous stirred tank reactor for a single type of feedstock. Although the characteristics of anaerobic digestion and properties of gas production at the process of continuous stirred tank reactor and semi- continuous feeding mode has been examined for crushed straw and silage straw as the fermentation substrate, but the operation parameters of such system has not been determined. Thus, in order to obtain the corresponding relationship between solid matter retention time for substrate and the characteristics of gas production, a comparative study to determine biogas production in batch fermentation and semi-continuous fermentation process was carried out under medium temperature conditions with rice straw as feedstock. The effect of quality content of total solid in the batch and continuous biogas fermentation of straws was studied. The volume of gas production rate and the rate of raw material gas production were used as characteristic indicators in order to obtain parameter on optimum quality content of total solid and solid matter retention time for biogas plant with straws. The results showed that fermentation concentration of single straw type used for anaerobic fermentation raw material influenced the gas volume rate under the condition of batch fermentation. With the increase of total solid concentration, the volume of gas production rate was increased in batch fermentation process, but the trend of the increase was gradually decreasing. The volume of gas production rate was improved under condition of intermittent

  17. (1)H NMR-based metabolomic approach for understanding the fermentation behaviors of wine yeast strains.

    Science.gov (United States)

    Son, Hong-Seok; Hwang, Geum-Sook; Kim, Ki Myong; Kim, Eun-Young; van den Berg, Frans; Park, Won-Mok; Lee, Cherl-Ho; Hong, Young-Shick

    2009-02-01

    (1)H NMR spectroscopy coupled with multivariate statistical analysis was used for the first time to investigate metabolic changes in musts during alcoholic fermentation and wines during aging. Three Saccharomyces cerevisiae yeast strains (RC-212, KIV-1116, and KUBY-501) were also evaluated for their impacts on the metabolic changes in must and wine. Pattern recognition (PR) methods, including PCA, PLS-DA, and OPLS-DA scores plots, showed clear differences for metabolites among musts or wines for each fermentation stage up to 6 months. Metabolites responsible for the differentiation were identified as valine, 2,3-butanediol (2,3-BD), pyruvate, succinate, proline, citrate, glycerol, malate, tartarate, glucose, N-methylnicotinic acid (NMNA), and polyphenol compounds. PCA scores plots showed continuous movements away from days 1 to 8 in all musts for all yeast strains, indicating continuous and active fermentation. During alcoholic fermentation, the highest levels of 2,3-BD, succinate, and glycerol were found in musts with the KIV-1116 strain, which showed the fastest fermentation or highest fermentative activity of the three strains, whereas the KUBY-501 strain showed the slowest fermentative activity. This study highlights the applicability of NMR-based metabolomics for monitoring wine fermentation and evaluating the fermentative characteristics of yeast strains.

  18. Green and brown propolis: efficient natural biocides for the control of bacterial contamination of alcoholic fermentation of distilled beverage

    Directory of Open Access Journals (Sweden)

    Márcia Justino Rossini Mutton

    2014-12-01

    Full Text Available This study aimed to evaluate the efficiency of natural biocides, brown and green propolis, for the control of bacterial contamination in the production of sugarcane spirit. The treatments consisted of brown and green propolis extracts, ampicillin, and a control and were assessed at the beginning and end of harvest season in ten fermentation cycles. In the microbiological analyses, the lactic acid bacteria were quantified in the inoculum before and after the treatment with biocides, and the viability of yeast cells during fermentation was evaluated. The levels of acids, glycerol, total residual reducing sugars, and ethanol were analyzed for the wine resulting from each fermentation cycle. A reduction in the number of bacterial contaminants in the inoculum in the treatments with the natural biocides was observed, but it did not affect the viability of yeast cells. The control of the contaminants led to the production of higher levels of ethanol and reduced acidity in the wine produced. The results of the use of brown and green propolis to control the growth microorganisms in the fermentation of sugarcane spirit can be of great importance for using alternative strategies to synthetic antibacterials in fermentation processes including other distilled beverage or spirits.

  19. Change ofresveratrol content in muscat wine during alcohol fermentation%玫瑰香葡萄酒精发酵过程中白藜芦醇含量的变化研究

    Institute of Scientific and Technical Information of China (English)

    胡云峰; 肖娟

    2011-01-01

    Variation of resveratrol contents of Chadian muscat wine during alcohol fermentation were determined by HPLC, and optimal alcohol fermentation time of muscat wine was obtained with combined sensory evaluation. The results showed that during alcohol fermentation period, resveratrol contents in raw wine increased first and then decreased, and finally kept at stable level. The highest resveratrol content occurred at 96h fermentation, the wine reached the highest sensory evaluation score was 85 and the alcohol content was more than 10% vol.%采用高效液相色谱法测定天津茶淀玫瑰香葡萄酒精发酵过程中白藜芦醇含量变化,并结合感官评价手段,确定最优的玫瑰香葡萄酒酒精发酵时间.结果表明,在天津茶淀玫瑰香酒精发酵过程中,随着时间的变化,原酒中白藜芦醇含量出现先升高再降低最后趋于稳定的趋势,酒精发酵96h时的原酒白藜芦醇含量最高,感官评价的得分为最高分85,酒精度达到10%vol以上.

  20. Effect of pressure and temperature on alcoholic fermentation by Saccharomyces cerevisiae immobilized on γ-alumina pellets.

    Science.gov (United States)

    Galanakis, Charis M; Kordulis, Christos; Kanellaki, Maria; Koutinas, Athanasios A; Bekatorou, Argyro; Lycourghiotis, Alexis

    2012-06-01

    Saccharomyces cerevisiae was immobilized on γ-alumina pellets and used for repeated batch fermentations in glucose medium (16.5 g/100 mL) at various temperatures and pressures. An increase in pressure from 3 to 7 atm and a decrease in temperature from 30 to 20 °C reduced the ethanol productivity by about 50% and 70%, respectively. Increasing concentrations of volatile by-products were observed at lower fermentation temperatures, while the pressure influence on the concentrations of these by-products was proved to be more complex. Mathematical expressions were established to allow the calculation of the fermentation rate at various pressures and sugar concentrations when the corresponding rate at atmospheric pressure is known. The study showed that the height of bioreactors has to be limited to 19.5 m due to hydrostatic pressure shock at higher fill levels.

  1. Effect of alcohol fermented feed on lactating performance, blood metabolites, milk Fatty Acid profile and cholesterol content in holstein lactating cows.

    Science.gov (United States)

    Li, X Z; Park, B K; Yan, C G; Choi, J G; Ahn, J S; Shin, J S

    2012-11-01

    A feeding experiment with 40 lactating Holstein cows and 4 dietary treatments was conducted to investigate supplementation with different levels of alcohol fermented feed to the TMR on lactating performance, blood metabolites, milk fatty acid profile and cholesterol concentration of blood and milk. Forty Holstein lactating cows (106±24 d post-partum; mean±SD) were distributed into four groups and randomly assigned to one of four treatments with each containing 10 cows per treatment. The treatment supplemented with TMR (DM basis) as the control (CON), and CON mixed with alcohol-fermented feeds (AFF) at a level of 5%, 10% and 15% of the TMR as T1, T2 and T3, respectively. Dry matter intake and milk yield were not affected by supplementation of AFF. An increased 4% FCM in the milk occurred in cows fed T3 diet compared with CON, while T1 and T2 diets decreased 4% FCM in a dose dependent manner. Supplementation of AFF increased the concentration of albumin, total protein (TP), ammonia, and high density lipoprotein-cholesterol in serum compared with CON. In contrast, supplementation with AFF clearly decreased concentration of blood urea nitrogen (BUN) and total cholesterol (TC) compare with CON. AFF supplementation increased the proportion of C18:1n9 and C18:2n6 compared to CON. A decrease in the concentration of saturated fatty acid (SFA) for T1, T2 and T3 resulted in an increased unsaturated fatty acid (USFA) to SFA ratio compared to CON. Concentration of cholesterol in milk fat was reduced in proportion to the supplemental level of AFF. Feeding a diet supplemented with a moderate level AFF to lactating cows could be a way to alter the feed efficiency and fatty acid profile of milk by increasing potentially human consumer healthy fatty acid without detrimental effects on feed intake and milk production. A substantially decreased cholesterol proportion in milk induced by supplementation AFF suggests that alcohol fermented feed may improve milk cholesterol levels

  2. Effect of Alcohol Fermented Feed on Lactating Performance, Blood Metabolites, Milk Fatty Acid Profile and Cholesterol Content in Holstein Lactating Cows

    Directory of Open Access Journals (Sweden)

    X. Z. Li

    2012-11-01

    Full Text Available A feeding experiment with 40 lactating Holstein cows and 4 dietary treatments was conducted to investigate supplementation with different levels of alcohol fermented feed to the TMR on lactating performance, blood metabolites, milk fatty acid profile and cholesterol concentration of blood and milk. Forty Holstein lactating cows (106±24 d post-partum; mean±SD were distributed into four groups and randomly assigned to one of four treatments with each containing 10 cows per treatment. The treatment supplemented with TMR (DM basis as the control (CON, and CON mixed with alcohol-fermented feeds (AFF at a level of 5%, 10% and 15% of the TMR as T1, T2 and T3, respectively. Dry matter intake and milk yield were not affected by supplementation of AFF. An increased 4% FCM in the milk occurred in cows fed T3 diet compared with CON, while T1 and T2 diets decreased 4% FCM in a dose dependent manner. Supplementation of AFF increased the concentration of albumin, total protein (TP, ammonia, and high density lipoprotein-cholesterol in serum compared with CON. In contrast, supplementation with AFF clearly decreased concentration of blood urea nitrogen (BUN and total cholesterol (TC compare with CON. AFF supplementation increased the proportion of C18:1n9 and C18:2n6 compared to CON. A decrease in the concentration of saturated fatty acid (SFA for T1, T2 and T3 resulted in an increased unsaturated fatty acid (USFA to SFA ratio compared to CON. Concentration of cholesterol in milk fat was reduced in proportion to the supplemental level of AFF. Feeding a diet supplemented with a moderate level AFF to lactating cows could be a way to alter the feed efficiency and fatty acid profile of milk by increasing potentially human consumer healthy fatty acid without detrimental effects on feed intake and milk production. A substantially decreased cholesterol proportion in milk induced by supplementation AFF suggests that alcohol fermented feed may improve milk cholesterol

  3. Cultivos de alta densidad celular por retención interna: aplicación a la fermentación continua de etanol High cell density cultures produced by internal retention: application in continuous ethanol fermentation

    Directory of Open Access Journals (Sweden)

    Godoy Rubén Darío

    2004-12-01

    . This can be achieved by using techniques leading to high cell concentration and reducing inhibition by the end-product. One of the frequently employed methods involves cell recycling. This work thus developed a membrane reactor incorporating a filtration module with 5 u,m stainless steel tubular units inside a 3L stirred jar fermenter for investigating its application in continuous ethanol production. The effects of cell concentration and transmembrane pressure difference on permeate flux were evaluated for testing the filtration module's performance. The internal cell retention system was operated in Saccharomyces cerevisiae continuous culture derived from sucrose, once fermentation conditions had been selected (30 °C, 1.25 -1.75 vvm, pH 4.5. Filter unit permeability was maintained by applying pulses of air. More than 97% of the grown cells were retained in the fermenter, reaching 51 g/L cell concentration and 8.51 g/L.h average ethanol productivity in culture with internal cell retention; this was twice that obtained in a conventional continuous culture. Key words: Membrane reactor, Saccharomyces cerevisiae, alcoholic fermentation, cell recycling.

  4. Alcoholic fermentation of Saccharomyces cerevisiae, Pichia stipitis and Zymomonas mobilis in the presence of inhibitory compounds and seawater.

    Science.gov (United States)

    Gonçalves, Fabiano Avelino; dos Santos, Everaldo Silvino; de Macedo, Gorete Ribeiro

    2015-06-01

    Production of cellulosic ethanol and holocellulosic ethanol from vegetable or microbial biomass starts with a hydrolysate containing compounds which may produce negative effects in the enzymatic hydrolysis and fermentation stages due to the need of pretreatment of the materials. In this way, the simultaneous presence of hydroxymethylfurfural (HMF), furfural, acetic acid, levulinic acid, and formic acid in different concentrations was tested in the fermentation using Saccharomyces cerevisiae, Pichia stipitis, and Zymomonas mobilis. The substitution of freshwater by seawater in the culture medium was also analyzed. Thus, inhibitory effects were stronger in the fermentation using P. stipitis, followed by Z. mobilis and S. cerevisiae. Formic acid and acetic acid presented more significant effects among the inhibitory compounds, followed by HMF, furfural and levulinic acid. Fermentation performed in culture medium with seawater showed promising results, especially in the ethanol yield using S. cerevisiae (0.50 g ethanol/g glucose) and Z. mobilis (0.49 g ethanol/g glucose). Whereas the production of cellulosic ethanol and holocellulosic ethanol are in early stages of development on an industrial scale, and that the availability and use of freshwater may cause socio-environmental problems for expansion of ethanol production, the use of seawater appears as an alternative to mitigate this problem.

  5. Experiments with Fungi Part 2: Fermentation.

    Science.gov (United States)

    Dale, Michele; Hetherington, Shane

    1996-01-01

    Gives details of three experiments with alcoholic fermentation by yeasts which yield carbon dioxide and ethanol. Lists procedures for making cider, vinegar, and fermentation gases. Provides some historical background and detailed equipment requirements. (DDR)

  6. Yeasts Diversity in Fermented Foods and Beverages

    Science.gov (United States)

    Tamang, Jyoti Prakash; Fleet, Graham H.

    People across the world have learnt to culture and use the essential microorganisms for production of fermented foods and alcoholic beverages. A fermented food is produced either spontaneously or by adding mixed/pure starter culture(s). Yeasts are among the essential functional microorganisms encountered in many fermented foods, and are commercially used in production of baker's yeast, breads, wine, beer, cheese, etc. In Asia, moulds are predominant followed by amylolytic and alcohol-producing yeasts in the fermentation processes, whereas in Africa, Europe, Australia and America, fermented products are prepared exclusively using bacteria or bacteria-yeasts mixed cultures. This chapter would focus on the varieties of fermented foods and alcoholic beverages produced by yeasts, their microbiology and role in food fermentation, widely used commercial starters (pilot production, molecular aspects), production technology of some common commercial fermented foods and alcoholic beverages, toxicity and food safety using yeasts cultures and socio-economy

  7. Characterization of bacterial diversity in pulque, a traditional Mexican alcoholic fermented beverage, as determined by 16S rDNA analysis.

    Science.gov (United States)

    Escalante, Adelfo; Rodríguez, María Elena; Martínez, Alfredo; López-Munguía, Agustín; Bolívar, Francisco; Gosset, Guillermo

    2004-06-15

    The bacterial diversity in pulque, a traditional Mexican alcoholic fermented beverage, was studied in 16S rDNA clone libraries from three pulque samples. Sequenced clones identified as Lactobacillus acidophilus, Lactobacillus strain ASF360, L. kefir, L. acetotolerans, L. hilgardii, L. plantarum, Leuconostoc pseudomesenteroides, Microbacterium arborescens, Flavobacterium johnsoniae, Acetobacter pomorium, Gluconobacter oxydans, and Hafnia alvei, were detected for the first time in pulque. Identity of 16S rDNA sequenced clones showed that bacterial diversity present among pulque samples is dominated by Lactobacillus species (80.97%). Seventy-eight clones exhibited less than 95% of relatedness to NCBI database sequences, which may indicate the presence of new species in pulque samples.

  8. Design and Investigation of PolyFermS In Vitro Continuous Fermentation Models Inoculated with Immobilized Fecal Microbiota Mimicking the Elderly Colon.

    Science.gov (United States)

    Fehlbaum, Sophie; Chassard, Christophe; Haug, Martina C; Fourmestraux, Candice; Derrien, Muriel; Lacroix, Christophe

    2015-01-01

    In vitro gut modeling is a useful approach to investigate some factors and mechanisms of the gut microbiota independent of the effects of the host. This study tested the use of immobilized fecal microbiota to develop different designs of continuous colonic fermentation models mimicking elderly gut fermentation. Model 1 was a three-stage fermentation mimicking the proximal, transverse and distal colon. Models 2 and 3 were based on the new PolyFermS platform composed of an inoculum reactor seeded with immobilized fecal microbiota and used to continuously inoculate with the same microbiota different second-stage reactors mounted in parallel. The main gut bacterial groups, microbial diversity and metabolite production were monitored in effluents of all reactors using quantitative PCR, 16S rRNA gene 454-pyrosequencing, and HPLC, respectively. In all models, a diverse microbiota resembling the one tested in donor's fecal sample was established. Metabolic stability in inoculum reactors seeded with immobilized fecal microbiota was shown for operation times of up to 80 days. A high microbial and metabolic reproducibility was demonstrated for downstream control and experimental reactors of a PolyFermS model. The PolyFermS models tested here are particularly suited to investigate the effects of environmental factors, such as diet and drugs, in a controlled setting with the same microbiota source.

  9. Alcoholic fermentation by wild-type Hansenula polymorpha and Saccharomyces cerevisiae versus recombinant strains with an elevated level of intracellular glutathione.

    Science.gov (United States)

    Grabek-Lejko, Dorota; Kurylenko, Olena O; Sibirny, Vladimir A; Ubiyvovk, Vira M; Penninckx, Michel; Sibirny, Andriy A

    2011-11-01

    The ability of baker's yeast Saccharomyces cerevisiae and of the thermotolerant methylotrophic yeast Hansenula polymorpha to produce ethanol during alcoholic fermentation of glucose was compared between wild-type strains and recombinant strains possessing an elevated level of intracellular glutathione (GSH) due to overexpression of the first gene of GSH biosynthesis, gamma-glutamylcysteine synthetase, or of the central regulatory gene of sulfur metabolism, MET4. The analyzed strains of H. polymorpha with an elevated pool of intracellular GSH were found to accumulate almost twice as much ethanol as the wild-type strain during glucose fermentation, in contrast to GSH1-overexpressing S. cerevisiae strains, which also possessed an elevated pool of GSH. The ethanol tolerance of the GSH-overproducing strains was also determined. For this, the wild-type strain and transformants with an elevated GSH pool were compared for their viability upon exposure to exogenous ethanol. Unexpectedly, both S. cerevisiae and H. polymorpha transformants with a high GSH pool proved more sensitive to exogenous ethanol than the corresponding wild-type strains.

  10. Properties of cellulose-degrading enzymes from Aspergillus oryzae and their contribution to material utilization and alcohol yield in sake mash fermentation.

    Science.gov (United States)

    Yamane, Yu-Ichi; Fujita, Jin; Izuwa, Shinya; Fukuchi, Kaoru; Shimizu, Ryu-Ichi; Hiyoshi, Akira; Fukuda, Hisashi; Mikami, Shigeaki; Kizaki, Yasuzo; Wakabayashi, Saburo

    2002-01-01

    Four cellulose-degrading enzymes were identified in a solid-state culture of Aspergillus oryzae. The three major enzymes were purified and named Cel-1, Cel-2, and Cel-3, respectively. The molecular weights were determined to be 62, 120, and 34 kDa, respectively. The optimum temperature of Cel-3 activity was higher than that of the other enzymes. An acidic pH was found to be more suitable for Cel-1 activity than for the other enzymes, and Cel-3 was more stable under acidic conditions than the other two. These properties and the results of a protein homology search for N-terminal amino acid sequences suggest that Cel-1 and Cel-3 correspond to the previously isolated endo-1,4-beta-glucanase CelB and CelA, respectively. The analysis of substrate specificity suggested that Cel-2 is likely to be beta-glucosidase. The effect of Cel-1, Cel-2, and Cel-3 on the sake mash fermentation was determined and it was found that Cel-2 markedly improved material utilization and alcohol yield in sake mash fermentation.

  11. 木薯酒精发酵过程关键参数的测控研究%Dissolved Oxygen Measure and Control in Cassava Alcohol Fermentation Process

    Institute of Scientific and Technical Information of China (English)

    王章利; 谭永红

    2009-01-01

    木薯酒精发酵过程是一个时变、非线形和多参数影响的动态过程.时发酵过程的关键参数如pH值、溶解氧的测控是非常重要的.设计了由工控机和西门子公司的PLC构成的发酵过程两级计算机集散系统,实现对酒精发酵过程中关键参数pH值、溶解氧等的数据采集与监视,同时利用该系统实现对采集到的数据进行分析与处理,从而达到最终的控制目的.%Cassava Alcohol Fermentation Process is a non-linear,time-varying dynamic process with infection by many parameter.Si-multaneity,it's very important to measure and control pivotal parameter such as pH and DO (Dissolved Oxygen).This paper de-signs the DCS(Distributing Control System) which is made by industry PC and SIEMENS PLC.This system can achieve to col-lection and stakeout the pivotal parameter like pH and DO in alcohol fermentation.At the same time,using the system imple-mentation of the dissolved oxygen data collected for analysis and treatment,So as to achieve the ultimate control purposes.

  12. Development of industrial yeast strain with improved acid- and thermo-tolerance through evolution under continuous fermentation conditions followed by haploidization and mating.

    Science.gov (United States)

    Mitsumasu, Kanako; Liu, Ze-Shen; Tang, Yue-Qin; Akamatsu, Takashi; Taguchi, Hisataka; Kida, Kenji

    2014-12-01

    Continuous fermentation using the industrial Saccharomyces cerevisiae diploid strain WW was carried out under acidic or high-temperature conditions to achieve acid- or thermo-tolerant mutants. Mutants isolated at pH 2.5 and 41°C showed improved growth and fermentation ability under acidic and elevated temperature conditions. Haploid strains WW17A1 and WW17A4 obtained from the mutated diploid strain WW17A showed better growth and 4.5-6.5% higher ethanol yields at pH 2.7 than the original strains. Haploid strain WW12T4 obtained from mutated diploid strain WW12T showed 1.25-1.50 times and 2.8-4.7 times higher total cell number and cell viability, respectively, than the original strains at 42°C. Strain AT, which had significantly improved acid- and thermo-tolerance, was developed by mating strain WW17A1 with WW12T4. Batch fermentation at 41°C and pH 3.5 showed that the ethanol concentration and yield achieved during fermentation by strain AT were 55.4 g/L and 72.5%, respectively, which were 10 g/L and 13.4% higher than that of the original strain WW. The present study demonstrates that continuous cultivation followed by haploidization and mating is a powerful approach for enhancing the tolerance of industrial strains. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  13. 27 CFR 24.197 - Production by fermentation.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Production by fermentation... fermentation. In producing special natural wine by fermentation, flavoring materials may be added before or during fermentation. Special natural wine produced by fermentation may be ameliorated in the same...

  14. Nitrogen compounds in must and volatile profile of white wine: Influence of clarification process before alcoholic fermentation.

    Science.gov (United States)

    Burin, Vívian Maria; Caliari, Vinícius; Bordignon-Luiz, Marilde T

    2016-07-01

    The aim of this study was to investigate the effect of adding a fining agent to the must in relation to the fermentation kinetics and the volatile composition of the wine produced. Three fining agents, bentonite, pectinolytic enzyme and silica were applied, separately, to samples of Chardonnay must. It was observed that the addition of a fining agent had a significant influence on the must and wine composition. The must clarified with bentonite showed the lowest nitrogen content and the enzyme addition led to the highest nitrogen content. During the fermentation process, a difference in the consumption rate was observed for each amino acid in relation to the fining agent used in the process. In relation to the volatile composition, the wine produced had different characteristics according to the fining agent added to the must, which was confirmed by separation of the samples using principal component analysis.

  15. Screening of alcohol yeast strains and fermentation techniques optimizing in sugar cane juice%蔗汁酒精发酵中酵母菌株筛选及发酵工艺优化

    Institute of Scientific and Technical Information of China (English)

    李苗苗; 李丹; 于淑娟

    2011-01-01

    以甘蔗汁为培养基比较CICC1308、As2.1190、广西贵糖4608、As2.109(GIM2.34)和R12(GIM2.84)五株酿酒酵母的酒精发酵特性.通过酒精耐受性及发酵能力测试,选出适合蔗汁酒精发酵的菌株为CICC1308.通过CICC1308菌株发酵工艺的单因素试验对发酵液原始pH值、发酵温度、接种量及发酵时间进行优化.结果表明:发酵液原始pH值5.0、发酵温度30℃、接种量15%(v/v)和发酵时间60h为最优条件试验,酒精产率可达92.15%.%The fermentation characteristics of five yeast strains suitable to alcoholic fermentation by sugar cane juice medium were investigated in this paper. The yeast strain (CICC1308) with excellent fermentation performance was selected by alcohol resistance and fermentation experiments, and then the fermentation techniques of CICC1308 were optimized through the single factor tests. The results showed the highest alcohol production rate was up to 92.15% with initial pH(5.0), yeast inoculation (15%)at 30℃ after 60h fermentation.

  16. Application of a slurry feeder to 1 and 3 stage continuous simultaneous saccharification and fermentation of dilute acid pretreated corn stover.

    Science.gov (United States)

    Brethauer, Simone; Studer, Michael H; Wyman, Charles E

    2014-10-01

    Continuous operation is often chosen for conceptual designs of biological processing of cellulosic biomass to ethanol to achieve higher volumetric productivities. Furthermore, continuous stirred tank reactors (CSTR) can handle higher solids concentrations than possible in batch mode due to broth thinning at partial conversion in a continuous fermentor. However, experience and literature data are very limited for continuous simultaneous saccharification and fermentation (cSSF) processes. In this work, a slurry feed system was developed and applied to a 3-stage bench-scale cSSF train to convert pretreated corn stover to ethanol and determine the effects of dilution rate and number of fermentation vessels on overall volumetric productivity. The highest productivity of 0.4gL(-1)h(-1) was achieved in a single cSSF vessel with an 8h residence time. Furthermore, productivity at identical total residence times was 12% higher for operation with 3 cSSF stages than for a single CSTR stage for pretreated corn stover.

  17. Application of New-type Organic Nitrogen in Alcohol Fermentation by Wheat Starch%新型有机氮在小麦淀粉酒精发酵中的应用研究

    Institute of Scientific and Technical Information of China (English)

    张志军; 施清; 罗天; 韩永超; 刘小民; 李志军

    2014-01-01

    对有机氮-发酵促进剂SP1在小麦淀粉酒精发酵过程中的应用进行了实验室及大生产试验和分析。结果表明,在酒母培养中添加发酵促进剂SP1对小麦酒精发酵有明显的促进作用,酒母形态明显改善,相对酒母出芽率提高了5.83%,细胞活力提升明显,能有效抑制杂菌对发酵系统的干扰,稳定发酵终了酸度、降低发酵残糖水平,有效地提高了原料的利用率。%Lab test and production test of the application of organic nitrogen-fermentation promoter SP1 in alcohol fermentation by wheat starch were done. The results showed that, the addition of fermentation promoter SP1 in wine yeast culture could significantly promote alcohol fermenta-tion by wheat starch, evidently improve wine yeast properties (yeast budding rate increased by 5.83%), increase cell activities, effectively inhibit the interference of bacteria to the fermentation, stabilize the final acidity at the end of the fermentation, reduce the residual sugar content in the fermentation, and effectively increase the utilization rate of raw materials. (Trans. by YUE Yang).

  18. Chronic intake of fermented floral nectar by wild treeshrews.

    Science.gov (United States)

    Wiens, Frank; Zitzmann, Annette; Lachance, Marc-André; Yegles, Michel; Pragst, Fritz; Wurst, Friedrich M; von Holst, Dietrich; Guan, Saw Leng; Spanagel, Rainer

    2008-07-29

    For humans alcohol consumption often has devastating consequences. Wild mammals may also be behaviorally and physiologically challenged by alcohol in their food. Here, we provide a detailed account of chronic alcohol intake by mammals as part of a coevolved relationship with a plant. We discovered that seven mammalian species in a West Malaysian rainforest consume alcoholic nectar daily from flower buds of the bertam palm (Eugeissona tristis), which they pollinate. The 3.8% maximum alcohol concentration (mean: 0.6%; median: 0.5%) that we recorded is among the highest ever reported in a natural food. Nectar high in alcohol is facilitated by specialized flower buds that harbor a fermenting yeast community, including several species new to science. Pentailed treeshrews (Ptilocercus lowii) frequently consume alcohol doses from the inflorescences that would intoxicate humans. Yet, the flower-visiting mammals showed no signs of intoxication. Analysis of an alcohol metabolite (ethyl glucuronide) in their hair yielded concentrations higher than those in humans with similarly high alcohol intake. The pentailed treeshrew is considered a living model for extinct mammals representing the stock from which all extinct and living treeshrews and primates radiated. Therefore, we hypothesize that moderate to high alcohol intake was present early on in the evolution of these closely related lineages. It is yet unclear to what extent treeshrews benefit from ingested alcohol per se and how they mitigate the risk of continuous high blood alcohol concentrations.

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

    Directory of Open Access Journals (Sweden)

    Rasmus Lund Andersen

    Full Text Available 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.

  20. 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.

  1. An Approach to Continuous Approximation of Pareto Front Using Geometric Support Vector Regression for Multi-objective Optimization of Fermentation Process

    Institute of Scientific and Technical Information of China (English)

    Jiahuan Wu; Jianlin Wang; Tao Yu; Liqiang Zhao

    2014-01-01

    The approaches to discrete approximation of Pareto front using multi-objective evolutionary algorithms have the problems of heavy computation burden, long running time and missing Pareto optimal points. In order to overcome these problems, an approach to continuous approximation of Pareto front using geometric support vector regression is presented. The regression model of the small size approximate discrete Pareto front is constructed by geometric support vector regression modeling and is described as the approximate continuous Pareto front. In the process of geometric support vector regression modeling, considering the distribution characteristic of Pareto optimal points, the separable augmented training sample sets are constructed by shifting original training sample points along multiple coordinated axes. Besides, an interactive decision-making (DM) procedure, in which the continuous approximation of Pareto front and decision-making is performed interactive-ly, is designed for improving the accuracy of the preferred Pareto optimal point. The correctness of the continuous approximation of Pareto front is demonstrated with a typical multi-objective optimization problem. In addition, combined with the interactive decision-making procedure, the continuous approximation of Pareto front is applied in the multi-objective optimization for an industrial fed-batch yeast fermentation process. The experi-mental results show that the generated approximate continuous Pareto front has good accuracy and complete-ness. Compared with the multi-objective evolutionary algorithm with large size population, a more accurate preferred Pareto optimal point can be obtained from the approximate continuous Pareto front with less compu-tation and shorter running time. The operation strategy corresponding to the final preferred Pareto optimal point generated by the interactive DM procedure can improve the production indexes of the fermentation process effectively.

  2. EXPERIMENTAL STUDIES ON THE FERMENTATION IN ASAVAS AND ARISTAS PART II - DRAKSHASAVA

    OpenAIRE

    Muzaffer, Alam; Dasan, K. K. S.; Ramar, C.; Ali, S. Usman; Purushothaman, K. K.

    1983-01-01

    A saccharomyces sp. causing fermentation in Meduca asava was isolated from Maduca flowers (Maduca longifolia Macbride). The capability of the organism to cause fermentation in Drakshasava was carried out. The Saccharomyces sp. caused alcoholic fermentation and the alcoholic fermentation and the alcohol produced was almost equal in quantity to that prepared according to textual method. The change in the pH of fermenting medium did not help in increased production of alcohol.

  3. Production of Solvent (acetone-butanol-ethanol in Continuous Fermentation by Clostridium saccharobutylicum DSM 13864 Using Gelatinised Sago Starch as a Carbon Source

    Directory of Open Access Journals (Sweden)

    Liew, S. T.

    2006-01-01

    Full Text Available Solvent production by Clostridium saccharobutylicum DSM 13864 was carried out in a single stage continuous culture using 2 L stirred tank fermenter with gelatinised sago starch as a carbon source. From the study it was found that the condition could be adjusted to suit for acids production (high dilution rate and high pH or solvent production (low dilution rate and low pH by manipulating the dilution rate and culture pH of single stage continuous fermentation. The highest solvent concentration in outflow (9.10 g/L was obtained at pH 4.5 and dilution rate of 0.05 h^1, which corresponds to overall productivity of 0.46 g/L.h. However, the highest total solvent productivity (0.85 g/L.h was obtained at dilution rate of 0.11 h-1 and pH 4.5, which gave a total solvent yield of 0.29 g solvent/g sago starch. Although the total solvent productivity was greatly increased in continuous culture, the final solvent concentration attained in outflow was decreased by about 53% as compared to batch culture.

  4. Fermentation of lignocellulosic hydrolysates: Inhibition and detoxification

    Energy Technology Data Exchange (ETDEWEB)

    Palmqvist, E.

    1998-02-01

    The ethanol yield and productivity obtained during fermentation of lignocellulosic hydrolysates is decreased due to the presence of inhibiting compounds, such as weak acids, furans and phenolic compounds produced during hydrolysis. Evaluation of the effect of various biological, physical and chemical detoxification treatments by fermentation assays using Saccharomyces cerevisiae was used to characterise inhibitors. Inhibition of fermentation was decreased after removal of the non-volatile compounds, pre-fermentation by the filamentous fungus Trichoderma reesei, treatment with the lignolytic enzyme laccase, extraction with ether, and treatment with alkali. Yeast growth in lignocellulosic hydrolysates was inhibited below a certain fermentation pH, most likely due to high concentrations of undissociated weak acids. The effect of individual compounds were studied in model fermentations. Furfural is reduced to furfuryl alcohol by yeast dehydrogenases, thereby affecting the intracellular redox balance. As a result, acetaldehyde accumulated during furfural reduction, which most likely contributed to inhibition of growth. Acetic acid (10 g 1{sup -1}) and furfural (3 g 1{sup -1}) interacted antagonistically causing decreased specific growth rate, whereas no significant individual or interaction effects were detected by the lignin-derived compound 4-hydroxybenzoic acid (2 g 1{sup -1}). By maintaining a high cell mass density in the fermentor, the process was less sensitive to inhibitors affecting growth and to fluctuations in fermentation pH, and in addition the depletion rate of bioconvertible inhibitors was increased. A theoretical ethanol yield and high productivity was obtained in continuous fermentation of spruce hydrolysate when the cell mass concentration was maintained at a high level by applying cell recirculation 164 refs, 16 figs, 5 tabs

  5. The Brewing Process: Optimizing the Fermentation

    Directory of Open Access Journals (Sweden)

    Teodora Coldea

    2014-11-01

    Full Text Available Beer is a carbonated alcoholic beverage obtained by alcoholic fermentation of malt wort boiled with hops. Brown beer obtained at Beer Pilot Station of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca was the result of a recipe based on blond, caramel and black malt in different proportions, water, hops and yeast. This study aimed to monitorize the evolution of wort in primary and secondary alcoholic fermentation in order to optimize the process. Two wort batches were assambled in order to increase the brewing yeast fermentation performance. The primary fermentation was 14 days, followed by another 14 days of secondary fermentation (maturation. The must fermentation monitoring was done by the automatic FermentoStar analyzer. The whole fermentation process was monitorized (temperature, pH, alcohol concentration, apparent and total wort extract.

  6. A new method for monitoring the extracellular proteolytic activity of wine yeasts during alcoholic fermentation of grape must.

    Science.gov (United States)

    Chasseriaud, Laura; Miot-Sertier, Cécile; Coulon, Joana; Iturmendi, Nerea; Moine, Virginie; Albertin, Warren; Bely, Marina

    2015-12-01

    The existing methods for testing proteolytic activity are time consuming, quite difficult to perform, and do not allow real-time monitoring. Proteases have attracted considerable interest in winemaking and some yeast species naturally present in grape must, such as Metschnikowia pulcherrima, are capable of expressing this activity. In this study, a new test is proposed for measuring proteolytic activity directly in fermenting grape must, using azocasein, a chromogenic substrate. Several yeast strains were tested and differences in proteolytic activity were observed. Moreover, analysis of grape must proteins in wines revealed that protease secreted by Metschnikowia strains may be active against wine proteins.

  7. 啤酒固定化连续后发酵中两种载体性能的研究%Study on the performance of the two carriers in the immobilized continuous fermentation of the beer

    Institute of Scientific and Technical Information of China (English)

    陈光斌; 蒋玉梅; 李红; 肖侠; 邵威平; 康开萍

    2013-01-01

    The beech wood chip and the porous ceramic are used as yeast carriers,these two kinds of carriers were compared by immobilized effect, and the beer from continuous secondary fermentation by these two kind of carriers compared with the beer from traditional secondary fermentation.The results were as follows: the beech wood chips immobilized yeast were more than the porous ceramic 31.2% ,the rate of immobilization was more than 45.4%,the stability of the immobilized yeast was better than porous ceramic.Fermented beer by the two carriers compared with each other,which content of diacetyl was significantly different(p0.05) . Flavor substances, for example, acetaldehyde, ethyl formate, ethyl acetate, n-propanol,Isobutanol,Isoamyl acetate,isoamyl alcohol had significant differences(p0.05).The content of amino acids,tyrosine,leucine were not significant(p> 0.05) ,the rest of the amino acid contents had significant differences(p<0.05).%使用山毛榉木片和多孔陶瓷作为固定酵母的载体,对这两种载体在固定化连续后发酵中的固定化效果以及生产的啤酒的各项指标进行比较和研究.结果表明,与多孔陶瓷相比,山毛榉木片固定化酵母的量、达到饱和时速率分别高出31.2%、45.4%,且牢固程度较优.分别以山毛榉木片与多孔陶瓷作为载体,后酵生产的啤酒中双乙酰含量差异显著(p<0.05),其余指标差异不显著(p>0.05).风味物质中,乙醛、甲酸乙酯、乙酸乙酯、正丙醇、异丁醇、乙酸异戊酯、异戊醇的差异显著(p<0.05),其余风味物质的差异不显著(p>0.05).氨基酸含量中,酪氨酸、亮氨酸的含量差异不显著(p>0.05),其余氨基酸含量差异性显著(P<0.05).

  8. Alcohol fermentation from mixed molasses and the juice of Miscanthus sp.%三像草汁与糖蜜混合发酵生产酒精的研究

    Institute of Scientific and Technical Information of China (English)

    黎娅; 兰生葵; 程谦伟; 黄翠姬; 伍时华; 易弋

    2012-01-01

    为了合理利用三像草汁中的糖分,选用酿酒酵母GJ2008作为发酵菌种,通过三像草汁与糖蜜混合发酵的方式生产酒精。研究结果表明,在初始总糖18.0%~20.0%(m/v)左右,pH4.5,发酵温度32%,不添加营养盐和氮源的条件下,可获得较优的发酵结果,发酵酒精度在11.0%(v/v)左右,发酵效率达到90%。%In order to utilize the sugar contained in the juice of Sanxiang grass( Miscanthus sp.)effectively, the mixture of the juice and molasses were fermented to produce alcohol by Saccharomyces cerevisiae GJ2008.The results showed that the fermentation with up to 90% efficiency and 11% alcohol production obtained under the condition as follows :the initial total sugar and pH were 18.0% -20.0% (m/v) and 4.5, respectively,the fermentation temperature was 32℃, and the fermentation was done without additional salt and nitrogen source.

  9. Elimination of acetate production to improve ethanol yield during continuous synthesis gas fermentation by engineered biocatalyst Clostridium sp. MTEtOH550.

    Science.gov (United States)

    Berzin, Vel; Kiriukhin, Michael; Tyurin, Michael

    2012-05-01

    Acetogen strain Clostridum sp. MT653 produced acetate 273 mM (p Clostridum sp. MT653 was metabolically engineered to the biocatalyst strain Clostridium sp. MTEtOH550. The biocatalyst increased ethanol yield to 590 mM with no acetate production during single-stage continuous syngas fermentation due to expression of synthetic adh cloned in a multi-copy number expression vector. The acetate production was eliminated by inactivation of the pta gene in Clostridium sp. MTEtOH550. Gene introduction and gene elimination were achieved only using Syngas Biofuels Energy, Inc. electroporation generator. The electrotransformation efficiencies were 8.0 ± 0.2 × 10(6) per microgram of transforming DNA of the expression vector at cell viability ~15%. The frequency of suicidal vector integration to inactivate pta was ~10(-5) per the number of recipient cells. This is the first report on elimination of acetate production and overexpression of synthetic adh gene to engineer acetogen biocatalyst for selective biofuel ethanol production during continuous syngas fermentation.

  10. Continuous fermentation and in-situ reed separation of butyric acid for higher sugar consumption rate and productivity

    DEFF Research Database (Denmark)

    Baroi, George Nabin; Skiadas, Ioannis; Westermann, Peter;

    fermentation coupled with Reverse Enhanced Electro-Dialysis (REED) at D=0.0417 h-1 (1 day HRT) in experiments with a mixture of glucose and xylose in synthetic growth medium as well as with increasing concentrations of PHWS (up to 100%). Data obtained from experiments with synthetic medium showed......) and resulted in a butyric acid productivity and yield of 1.31g/L/h and 0.44 g/g, respectively at 1 day HRT. Acknowledgements: This work is a part of EU-7th Framework programme supported project SUPRABIO (FP7-cooperationproject no 241640)....

  11. Study on the Optimization Parameters of Alcoholic Fermentation as the Material of Potato%利用马铃薯生产酒精发酵工艺参数的研究

    Institute of Scientific and Technical Information of China (English)

    李兴革; 李志江; 牛广财; 左锋; 关琛

    2009-01-01

    Through the processing of the hquefactian and saccharification, the optimization parameters of alcoholic fermentation as the material of potato as the index of alcoholic productive rate were studied. The results showed that the initial concentration of saccharification liquid is 16°Bx, the dosage of yeast is 0.8%, the fermentation temperature, is 32℃, and the best fermentation time is 60 h, and the alcoholic productive rate could reach 17.12% under the best optimization parameters.%以马铃薯为原料,经液化、糖化等处理后发酵生产酒精,以出酒率为指标,研究发酵工艺中的最佳参数.试验结果表明,糖化液初始糖度为16°Bx,接入酵母量为0.8%,发酵温度32℃,发酵60 h,酒精出酒率可达17.12%.

  12. Influence of oxygen on alcoholic fermentation by a wine strain of Torulaspora delbrueckii: kinetics and carbon mass balance.

    Science.gov (United States)

    Brandam, Cédric; Lai, Quoc Phong; Julien-Ortiz, Anne; Taillandier, Patricia

    2013-01-01

    Torulaspora delbrueckii metabolism was assessed in a synthetic culture medium similar to grape must under various conditions: no aeration and three different oxygen feeds, in order to determine the effect of oxygen on metabolism. Carbon and nitrogen mass balances were calculated to quantify metabolic fluxes. The effect of oxygen was to decrease the flux of carbon going into the fermentation pathway in favor of growth. In the absence of aeration, higher amounts of glycerol were produced, probably to maintain the redox balance. The oxygen requirement of this strain was high, since even for the highest air supply oxygen became limiting after 24 h. Nevertheless, this strain developed well in the absence of oxygen and consumed 220 g/L of sugars (glucose/fructose) in 166 h at 20 °C, giving a good ethanol yield (0.50 g/g).

  13. Fed-batch alcoholic fermentation of sugar cane blackstrap molasses: Influence of the feeding rate on yeast yield and productivity

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, J.C.M. de; Aquarone, E.; Sato, S.; Brazzach, M.L.; Moraes, D.A. (Faculdade de Ciencias Farmaceuticas, Sao Paulo Univ., SP (Brazil)); Borzani, W. (Centro de Desenvolvimento Biotecnologico, Joinville, SC (Brazil))

    1993-02-01

    Fed-batch ethanol fermentation tests of sugar cane blackstrap molasses were carried out at 32deg C and pH 4.5-5.0, using pressed yeast as inoculum, and with no air supply. Two values of the fermentor filling-up time were adopted: 5 h and 7 h. The feeding rates obeyed equation F=F[sub 0].e[sup K.t], with K equal to 0.0, 0.2, 0.4, 0.6 and 0.8 h[sup -1]. The average yeast yields and the average yeast productivities increased up to 33% and 45%, respectively, while the ethanol yield (average=76%; standard deviation=4%) was practically unaffected when K increased from 0 to 0.8 h[sup -1]. (orig.).

  14. Continuous Acetone–Butanol–Ethanol (ABE) Fermentation with in Situ Solvent Recovery by Silicalite-1 Filled PDMS/PAN Composite Membrane

    DEFF Research Database (Denmark)

    Li, Jing; Chen, Xiangrong; Qi, Benkun

    2014-01-01

    The pervaporation (PV) performance of a thin-film silicalite-1 filled PDMS/PAN composite membrane was investigated in the continuous acetone–butanol–ethanol (ABE) production by a fermentation–PV coupled process. Results showed that continuous removal of ABE from the broth at three different...... dilution rates greatly increased both the solvent productivity and the glucose utilization rate, in comparison to the control batch fermentation. The high solvent productivity reduced the acid accumulation in the broths because most acids were reassimilated by cells for ABE production. Therefore, a higher...... total solvent yield of 0.37 g/g was obtained in the fermentation–PV coupled process, with a highly concentrated condensate containing 89.11–160.00 g/L ABE. During 268 h of the fermentation–PV coupled process, the PV membrane showed a high ABE separation factor of more than 30 and a total flux of 486...

  15. Development and Appl ication of Continuous Packing-tower Surface Fermentation Device%填料塔式连续表面发酵装置的研制及应用

    Institute of Scientific and Technical Information of China (English)

    傅亮; 陈宇哲; 彭英

    2014-01-01

    The research developed a kind of continuous packing-tower surface fermentation device,in which the RF4 Gluconacetobacter xylinus strain fermented the broth with ethanol into acetic acid.A comparison of total acidity and ADH enzyme activity of fermentation broth in continuous packing-tower sur-face fermentation device and static flask by single-batch fermentation and fed-batch fermentation is made.The results show that the ADH enzyme activity of fermentation broth reaches to 4.13 × 10-3 U/g and the total acidity peaks to 7.07 g/dL on the 13th day by fed-batch fermentation in contin-uous packing-tower surface fermentation device,whose total acidity increased by 1 3% and the fermen-tation time shortened by 1 5% compared with static fed-batch fermentation.The total acidity increased by 7 1% compared with static single-batch fermentation.%研制了一种填料塔式连续发酵装置,以木醋杆菌(Gluconacetobacter xylinus )RF4为菌种,用含乙醇培养液进行醋酸发酵。比较了该填料表面发酵装置与静置三角瓶各自进行单批和分批发酵的产酸和乙醇脱氢酶的活力。结果表明:在连续填料发酵装置中进行分批补料发酵,发酵液中的乙醇脱氢酶活力为4.13×10-3 U/g,总酸度在第13天达到峰值7.07 g/dL。比静置分批补料发酵酸度提高13%,时间缩短15%,比静置单批发酵酸度提高71%。

  16. Continuous methane fermentation and the production of vitamin B12 in a fixed-bed reactor packed with loofah.

    Science.gov (United States)

    Yang, Yingnan; Zhang, Zhenya; Lu, Jun; Maekawa, Takaaki

    2004-05-01

    A fixed-bed reactor with acclimated methanogens immobilized on a loofah support was studied on a laboratory scale to evaluate the system producing methane from the mixture of CO(2) and H(2) gas, with the production of vitamin B(12) as a by-product. Fermentation using CO(2)/H(2) acclimated methanogens was conducted in a jar fermentor with hydraulic retention times (HRTs) of three and six days. The performance of the reactor was mainly dependent on the HRT. With an HRT of three days, the methane production rate and the vitamin B(12) concentration in the culture broth were 6.18 l/l-reactor/h and 2.88 mg/l-culture liquid; these values were 11.96 l/l-reactor/h and 37.54 mg/l-culture liquid for an HRT of six days. A higher total cell mass of methanogens retained 42.5 g dry cell/l-culture liquid was achieved in the HRT of six days. The loofah carrier immobilized almost 95% of the methanogens, which led to a more effective bio-reaction. It was also observed that the fermentation system had a better ability to buffer pH, especially for an HRT of six days.

  17. Survival of foodborne pathogenic bacteria (Bacillus cereus, Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, Staphylococcus aureus, and Listeria monocytogenes) and Bacillus cereus spores in fermented alcoholic beverages (beer and refined rice wine).

    Science.gov (United States)

    Kim, S A; Kim, N H; Lee, S H; Hwang, I G; Rhee, M S

    2014-03-01

    Only limited information is available on the microbiological safety of fermented alcoholic beverages because it is still a common belief that such beverages do not provide a favorable environment for bacterial growth and survival. Thus, in this study, we examined the survival of major foodborne pathogens and spores in fermented alcoholic beverages. Foodborne pathogens (Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica serovar Typhimurium, and Staphylococcus aureus) and B. cereus spores (initial population, 3 to 4 log CFU/ml) were inoculated separately into three types of beer and refined rice wine, which were then stored at 5 and 22°C. Bacterial counts were assayed periodically for up to 28 days. Vegetative B. cereus counts decreased rapidly, whereas B. cereus spore counts remained constant (P > 0.05) for a long period of time in all beverages. Vegetative B. cereus cells formed spores in beer at 5 and 22°C, and the spores survived for long periods. Among vegetative cells, E. coli O157:H7 had the highest survival (only 1.49 to 1.56 log reduction during 28 days in beer at 5°C). Beer and refined rice wine supported microbial survival from several days to several weeks. Our results appear to contradict the common belief that pathogens cannot survive in alcoholic beverages. Long-term survival of pathogens (especially B. cereus and E. coli O157:H7) in beer and refined rice wine should be taken into consideration by the manufacturers of these beverages. This study provides basic information that should help further research into microbial survival in alcoholic beverages and increase the microbiological safety regulation of fermented alcoholic beverages.

  18. Production of trans C18:1 and conjugated linoleic acid in continuous culture fermenters fed diets containing fish oil and sunflower oil with decreasing levels of forage.

    Science.gov (United States)

    Abughazaleh, A; Jacobson, B N

    2007-06-01

    Previously, feeding fish oil (FO) and sunflower seeds to dairy cows resulted in the greatest increases in the concentrations of vaccenic acid (VA, t11 C18:1) and conjugated linoleic acid (CLA) in milk fat. The objective of this study was to evaluate the effects of forage level in diets containing FO and sunflower oil (SFO) on the production of trans C18:1 and CLA by mixed ruminal microbes. A dual-flow continuous culture system consisting of three fermenters was used in a 3 × 3 Latin-square design. Treatments consisted of (1) 75:25 forage:concentrate (HF); (2) 50:50 forage:concentrate (MF); and (3) 25:75 forage:concentrate (LF). FO and SFO were added to each diet at 1 and 2 g/100 g dry matter (DM), respectively. The forage source was alfalfa pellets. During 10-day incubations, fermenters were fed treatment diets three times daily (140 g/day, divided equally between three feedings) as TMR diet. Effluents from the last 3 days of incubation were collected and composited for analysis. The concentration of trans C18:1 (17.20, 26.60, and 36.08 mg/g DM overflow for HF, MF, and LF treatments, respectively) increased while CLA (2.53, 2.35, and 0.81 mg/g DM overflow) decreased in a linear manner ( P effluent increased ( P effluent decreased in a linear manner ( P < 0.05) as dietary forage levels decreased. Decreasing dietary forage levels resulted in t10 C18:1 and t10c12 CLA replacing VA and c9t11 CLA, respectively, in fermenters fed FO and SFO.

  19. Optimization of the Cassava Alcohol Fermentation Conditions for Thermotolerant Saccharomyces cerevisiae%耐高温酿酒酵母木薯乙醇发酵条件的优化

    Institute of Scientific and Technical Information of China (English)

    刘晓红; 宋瑶; 周梦舟; 缪礼鸿

    2012-01-01

    The impact factors of cassava alcohol fermentation by a thermotolerant strain XG-1 of Saccharomyces cerevisiae were studied via single factor experiments and orthogonal design. The results showed that in 40 ℃, XG-1 was more sensitive to alcohol that affecting the cassava fermentation, and the effect of each factor was fermentation temperature >inoculated cell number = fermentation time. The optimum alcohol fermentation conditions were XG-1 inoculated cell number l.0×l07 CFU/mL; cassava starch concentration, 200 g/L; fermentation temperature, 33 ℃ ; and fermentation time, 72 h; additive amount of (NH4)2SO4, 8 g/L. The volume fraction of ethanoi reached 13.1%; and the starch utilization rate reached to 92.0% under these conditions.%通过单因素试验和正交试验,对耐高温酿酒酵母(Saccharomyces cerevisiae)XG-1的木薯乙醇发酵的主要影响因素进行了研究.结果表明,在40℃高温培养条件下,XG-1对乙醇更加敏感,影响其木薯乙醇发酵,而影响木薯乙醇发酵各因素的主次顺序为发酵温度>接种量=发酵时间.木薯乙醇发酵最佳工艺条件为发酵液中木薯淀粉含量200 g/L,氮素[(NH4)2SO4]添加量8 g/L,XG-1接种量约1.0×107CFU/mL,发酵温度33℃,发酵时间72h,发酵结束时发酵液中乙醇体积分教为13.1%,淀粉利用率为92.0%.

  20. Microbiological diversity and prevalence of spoilage and pathogenic bacteria in commercial fermented alcoholic beverages (beer, fruit wine, refined rice wine, and yakju).

    Science.gov (United States)

    Jeon, Se Hui; Kim, Nam Hee; Shim, Moon Bo; Jeon, Young Wook; Ahn, Ji Hye; Lee, Soon Ho; Hwang, In Gyun; Rhee, Min Suk

    2015-04-01

    The present study examined 469 commercially available fermented alcoholic beverages (FABs), including beer (draft, microbrewed, and pasteurized), fruit wine (grape and others), refined rice wine, and yakju (raw and pasteurized). Samples were screened for Escherichia coli and eight foodborne pathogens (Bacillus cereus, Campylobacter jejuni, Clostridium perfringens, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., Staphylococcus aureus, and Yersinia enterocolitica), and the aerobic plate count, lactic acid bacteria, acetic acid bacteria, fungi, and total coliforms were also enumerated. Microbrewed beer contained the highest number of microorganisms (average aerobic plate count, 3.5; lactic acid bacteria, 2.1; acetic acid bacteria, 2.0; and fungi, 3.6 log CFU/ml), followed by draft beer and yakju (P beverages should be taken into account (alongside traditional quality indicators such as the presence of lactic acid-producing bacteria, acetic acid-producing bacteria, or both) when developing manufacturing systems and methods to prolong the shelf life of high-quality FAB products. New strategic quality management plans for various FABs are needed.

  1. 酿酒酵母产乙醇脱氢酶发酵条件的研究%Study on fermentation conditions of alcohol dehydrogenase from Saccharomyces cerevisiae

    Institute of Scientific and Technical Information of China (English)

    吴桂英; 金放; 吴元欣

    2009-01-01

    选择了一株酿酒酵母菌(Saccharomyces cerevisiae)As 2.399,通过单因素和正交实验得到酿酒酵母产乙醇脱氢酶(Alcohol Dehydrogenase,ADH)的最优发酵条件结果表明:产ADH的最优培养条件是温度为25℃、pH为5、通气量为250mL、接种量为7%,液体发酵培养中pH对ADH活性的影响最大.%A strain yeast Saccharomyces cerevisiae As2.399 was selected to produce ADH. The fermentation conditions of yeast were optimized with single factor and orthogonal test.The result showed that high quality ADH could be produced at the temperature 25℃,the initial pH5.0,medium volume 250mL and the inoculums 7% (v/v).

  2. Metodologia para elaboração de fermentado de cajá (Spondias mombin L. Methodology for elaboration of fermented alcoholic beverage from yellow mombin (Spondias mombin

    Directory of Open Access Journals (Sweden)

    Disney Ribeiro Dias

    2003-12-01

    mombin fruit pulp had its sugar content adjusted to 24°Brix with a sucrose solution. The must was deacidified using CaCO3 until it reached pH value of 3.8 and then enzymatically treated with Ultrazym AFP-L (Novo DK. Sulphur dioxide, as potassium metabissulfite, was used as an inhibitor of bacterial growth and as an antioxidant. Bentonite was also added to aid the must clarification. After these adjustments the must was inoculated with 10(7 cell/ml of Saccharomyces cerevisiae wild type strain. The fermentation was carried out at 22°C for 10 days, with daily monitoring of Brix and fermentation activity by the liberation of CO2. At the end of the fermentation, the fermented must was stored at 10°C for 10 days and a first separation of the yeasts and solids particles was done. The second separation was done 30 days later, before the filtration. Ethanol, glycerol, organic acids, higher alcohols, methanol, esters and acetaldehyde were analysed in the final product. There was a high concentration of higher alcohols, which are usually responsible for the flavour found in alcoholic beverages. The acceptance of the drink was tested with 45 non-experienced panellists using the hedonic scale (1-9. The beverage was well accepted and might be a good investiment for small or medium companies.

  3. Continuous and intermittent alcohol free-choice from pre-gestational time to lactation: focus on drinking trajectories and maternal behaviour

    Directory of Open Access Journals (Sweden)

    Anna eBrancato

    2016-03-01

    Full Text Available Background - Alcohol consumption during pregnancy and lactation induces detrimental consequences that are not limited to the direct in utero effects of the drug on foetuses, but extend to maternal care. However, the occurrence and severity of alcohol toxicity are related to the drinking pattern and the time of exposure. The present study investigated in female rats long-term alcohol drinking trajectories, by a continuous and intermittent free-choice paradigm, during pre-gestational time, pregnancy and lactation; moreover the consequences of long-term alcohol consumption on the response to natural reward and maternal behaviour were evaluated. Methods – Virgin female rats were exposed to home-cage two-bottle continuous- or intermittent alcohol (20% v/v vs. water choice regimen along 12 weeks and throughout pregnancy and lactation. Animals were tested for saccharin preference, and maternal behaviour was assessed by recording dams’ undisturbed spontaneous home-cage behaviour in the presence of their offspring. Results - Our results show that the intermittent alcohol drinking-pattern induced an escalation in alcohol intake during pre-gestational time and lactation more than the continuous access, while a reduction in alcohol consumption was observed during pregnancy, contrarily to the drinking trajectories of the continuous access-exposed rats. Long-term voluntary alcohol intake induced a decreased saccharin preference in virgin female rats and a significant reduction in maternal care, with respect to control dams, although the intermittent drinking produced a greater impairment than the continuous-access paradigm.Conclusion - The present data indicate that both alcohol-drinking patterns are associated to modifications in the drinking trajectories of female rats, in pre-gestational time, during pregnancy and lactation. Moreover, long-lasting alcohol intake can affect sensitivity to natural rewarding stimuli and maternal behaviour and sensitivity

  4. Fed-batch fermentation for n-butanol production from cassava bagasse hydrolysate in a fibrous bed bioreactor with continuous gas stripping.

    Science.gov (United States)

    Lu, Congcong; Zhao, Jingbo; Yang, Shang-Tian; Wei, Dong

    2012-01-01

    Concentrated cassava bagasse hydrolysate (CBH) containing 584.4 g/L glucose was studied for acetone-butanol-ethanol (ABE) fermentation with a hyper-butanol-producing Clostridium acetobutylicum strain in a fibrous bed bioreactor with gas stripping for continuous butanol recovery. With periodical nutrient supplementation, stable production of n-butanol from glucose in the CBH was maintained in the fed-batch fermentation over 263 h with an average sugar consumption rate of 1.28 g/L h and butanol productivity of 0.32±0.03 g/L h. A total of 108.5 g/L ABE (butanol: 76.4 g/L, acetone: 27.0 g/L, ethanol: 5.1 g/L) was produced, with an overall yield of 0.32±0.03 g/g glucose for ABE and 0.23±0.01 g/g glucose for butanol. The gas stripping process generated a product containing 10-16% (w/v) of butanol, ~4% (w/v) of acetone, a small amount of ethanol (butanol solution of ~64% (w/v) after phase separation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Performance comparison of a continuous-flow stirred-tank reactor and an anaerobic sequencing batch reactor for fermentative hydrogen production depending on substrate concentration.

    Science.gov (United States)

    Kim, S-H; Han, S-K; Shin, H-S

    2005-01-01

    This study was conducted to compare the performance of a continuous-flow stirred-tank reactor (CSTR) and an anaerobic sequencing batch reactor (ASBR) for fermentative hydrogen production at various substrate concentrations. Heat-treated anaerobic sludge was utilized as an inoculum, and hydraulic retention time (HRT) for each reactor was maintained at 12 h. At the influent sucrose concentration of 5 g COD/L, start-up was not successful in both reactors. The CSTR, which was started-up at 10 g COD/L, showed stable hydrogen production at the influent sucrose concentrations of 10-60 g COD/L during 203 days. Hydrogen production was dependent on substrate concentration, resulting in the highest performance at 30 g COD/L. At the lower substrate concentration, the hydrogen yield (based on hexose consumed) decreased with biomass reduction and changes in fermentation products. At the higher substrate concentration, substrate inhibition on biomass growth caused the decrease of carbohydrate degradation and hydrogen yield (based on hexose added). The ASBR showed higher biomass concentration and carbohydrate degradation efficiency than the CSTR, but hydrogen production in the ASBR was less effective than that in the CSTR at all the substrate concentrations.

  6. Molecular cloning of alcohol dehydrogenase genes of the yeast Pichia stipitis and identification of the fermentative ADH.

    Science.gov (United States)

    Passoth, V; Schäfer, B; Liebel, B; Weierstall, T; Klinner, U

    1998-10-01

    Two Pichia stipitis ADH genes (PsADH1 and PsADH2) were isolated by complementation of a Saccharomyces cerevisiae Adh(-)-mutant. The genes enabled the transformants to grow in the presence of antimycin A on glucose, to use ethanol as sole carbon source and made them sensitive to allylalcohol. The sequences of the genes showed similarities of 70-77% to sequences of ADH genes of Candida albicans, Kluyveromyces lactis, K. marxianus, and S. cerevisiae and about 60% homology to those of Schizosaccharomyces pombe and Aspergillus flavus. Southern hybridization experiments suggested that P. stipitis has only these two ADH genes. Both genes are located on the largest chromosome of P. stipitis. PsADH2 encodes for the ADH activity that is responsible for ethanol formation at oxygen limitation. The gene is regulated at the transcriptional level. Moreover, also in cells grown on ethanol, only PsADH2 transcript was found. PsADH1 transcript was detected under aerobic conditions on fermentable carbon sources.

  7. Evaluation of continuous ethanol fermentation of dilute-acid corn stover hydrolysate using thermophilic anaerobic bacterium Thermoanaerobacter BG1L1

    DEFF Research Database (Denmark)

    Georgieva, Tania I.; Ahring, Birgitte Kiær

    2007-01-01

    Dilute sulfuric acid pretreated corn stover is potential feedstock of industrial interest for second generation fuel ethanol production. However, the toxicity of corn stover hydrolysate (PCS) has been a challenge for fermentation by recombinant xylose fermenting organisms. In this work...

  8. Gestational Alcohol Exposure and Other Factors Associated with Continued Teenage Drinking

    Science.gov (United States)

    Cornelius, Marie D.; Goldschmidt, Lidush; Day, Nancy L.

    2016-01-01

    Purpose: A longitudinal cohort of adolescents who initiated drinking before age 15 were studied to determine which factors distinguished between early initiators who continued to drink (persisters) from those who stopped drinking (desisters). There were 308 early initiators in the total sample (n = 917); 247 were persisters, and 61 were desisters.…

  9. 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...... by cellulose membranes with different pore sizes, i.e. 1000 kDa for mixed- and single-culture fermentations, and 1000 and 3.5-5 kDa for compartmentalized-culture fermentations. SDS-PAGE and gel filtration chromatography were used to determine an antimicrobial peptidic fraction in the fermentations. Our results...... showed comparable amounts of the antimicrobial peptidic fraction in the inner compartments of the mixed-culture and 1000 kDa compartmentalized-culture fermentations containing L. thermotolerans after 4 days of fermentation, but a lower death rate of L. thermotolerans in the 1000 kDa compartmentalized-culture...

  10. Profiling the hydA gene and hydA gene transcript levels of Clostridium butyricum during continuous, mixed-culture hydrogen fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Tolvanen, Katariina E.S.; Koskinen, Perttu E.P.; Santala, Ville P.; Karp, Matti T. [Department of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FI-33101 Tampere (Finland); Raussi, Hanna-Mari; Ylikoski, Alice I.; Hemmilae, Ilkka A. [PerkinElmer Life Sciences, Wallac Oy, P.O. Box 10, FI-20101 Turku (Finland)

    2008-10-15

    The purpose of the research was to investigate the hydrogenase (hydA) gene and the corresponding transcript levels of Clostridium butyricum during continuous hydrogen fermentation. A quantitative real-time PCR (qrt-PCR) method was developed to specifically target the C. butyricum hydrogenase gene and mRNA in samples collected from a continuous, mixed-culture bioreactor over a period of 30 days (operation days 114-144). The detection limit of the qrt-PCR was 3.9 x 10{sup 2}hydA copies and the linear range 3.9 x 10{sup 2}-3.9 x 10{sup 7}hydA copies. The results showed that after a re-inoculation of the bioreactor on day 120 the hydA copy numbers started to rise and stabilized after day 127. The number of hydA transcript continued to rise until day 142. The results demonstrate that this method is suitable for detecting the hydA gene and gene transcript levels of C. butyricum from bioreactor samples. The expression level of hydA gene changed during continuous operation and can, therefore, be a useful target for process performance monitoring. (author)

  11. Determination of the fate of alcohol ethoxylate homologues in a laboratory continuous activated-sludge unit study.

    Science.gov (United States)

    Wind, T; Stephenson, R J; Eadsforth, C V; Sherren, A; Toy, R

    2006-05-01

    Environmental monitoring indicates that the distribution of alcohol ethoxylate (AE) homologues in wastewater treatment plant (WWTP) effluents differs from the distribution in commercial AE products, with a relative higher proportion of fatty alcohol (AOH, which is AE with zero ethoxylation). To determine the contribution of AE-derived AOH to the total concentration of AE and AOH in WWTP effluents, we conducted a laboratory continuous activated-sludge study (CAS). This consisted of a test unit fed with AE-amended synthetic sewage and a control unit fed with only synthetic sewage to avoid AE contamination from the feed. The removal efficiencies of some 114 AE homologues were determined by the application of a specific and sensitive analytical method. The extent of the removal of AE ranged from 99.70% for C18 compounds to > 99.98% for C12-16. Relatively high-AOH concentrations were observed in the effluents from blank and test units. By building the concentration difference from the test minus the control unit, the AE in the CAS effluent originating from AE in the influent was determined. Thus, it could be shown that AOH represented only 19% of the total AE (EO0-18) in the CAS, while monitoring in 29 WWTP effluents (European, Canadian, and US) revealed in total a mean AOH fraction of 55% (5-82%) of the total AE (EO0-18). This shows that only a small fraction of AOH in WWTP effluents originates from AE entering the WWTP.

  12. Nisin production in a chitin-including continuous fermentation system with Lactococcus lactis displaying a cell wall chitin-binding domain.

    Science.gov (United States)

    Şimşek, Ömer

    2014-03-01

    The limiting factors in the continuous production of nisin are high amount of biomass loss and low dilution rate application. In this study, a chitin-including continuous nisin fermentation system (CICON-FER) was constructed for high volumetric nisin production using nisin producer L. lactis displaying cell wall chitin-binding domain (ChBD) together with chitin in the reactor. In this respect, the highest binding conditions of relevant L. lactis cells to chitin were determined. Then the chitin flakes carrying nisin-producing L. lactis cells were used within the CICON-FER system at different dilution rates (0.1-0.9 h⁻¹) and initial glucose concentrations (20-60 g l⁻¹). The results revealed that the pH 7 conditions and the use of 100 mM sodium phosphate buffer with 0.1 % Tween 20 and Triton X-100 significantly increased the binding capacity of ChBD displaying L. lactis cells to chitin. The constructed CICON-FER system maintained the presence of the ChBD surface displaying L. lactis cells in the reactor system until 0.9 h⁻¹ dilution rate that resulted in a considerably high level of volumetric nisin production and productivity (10,500 IU ml⁻¹ and 9,450 IU ml⁻¹ h⁻¹, respectively) with the combination of a 0.9-h⁻¹ dilution rate and a 40-g l⁻¹ initial glucose concentration. In conclusion, an innovative nisin fermentation system that yielded the highest nisin production thus far and that was feasible for industrial application was created.

  13. Valorization of onion waste and by-products: MCR-ALS applied to reveal the compositional profiles of alcoholic fermentations of onion juice monitored by near-infrared spectroscopy.

    Science.gov (United States)

    González-Sáiz, José-María; Esteban-Díez, Isabel; Rodríguez-Tecedor, Sofía; Pizarro, Consuelo

    2008-11-01

    The overall purpose of the project, of which this study is a part, was to examine the feasibility of onion waste as a support-substrate for the profitable production of food-grade products. This study focused on the efficient production of ethanol from worthless onions by transforming the onion juice into onion liquor via alcoholic fermentation with the yeast Saccharomyces cerevisiae. The onion bioethanol produced could be later used as a favorable substrate for acetic fermentation to finally obtain onion vinegar. Near-infrared spectroscopy (NIRS), coupled with the multivariate curve resolution-alternating least squares (MCR-ALS) method, has been used to reveal the compositional and spectral profiles for both substrates and products of alcoholic fermentation runs, that is, total sugars, ethanol, and biomass concentration. The ambiguity associated with the ALS calculation was resolved by applying suitable inequality and equality constraints. The quality of the results provided by the NIR-based MCR-ALS methodology adopted was evaluated by several performance indicators, including the variance explained by the model, the lack of fit and the agreement between the MCR-ALS achieved solution and the results computed by applying previously validated PLS reference models. An additional fermentation run was employed to test the actual predictive ability of the ALS model developed. For all the components resolved in the fermentation system studied (i.e., total sugars, ethanol, and biomass), the final model obtained showed a high predictive ability and suitable accuracy and precision, both in calibration and external validation, confirmed by the very good agreement between the ALS responses and the reference values (the coefficient of determination was, in all cases, very close to 1, and the statistics confirmed that no significant difference was found between PLS reference models and the MCR-ALS methodology applied). Thus, the proven reliability of the MCR-ALS model presented

  14. Process optimization on alcohol production using sweet potato residue by simultaneous saccharification and fermentation method%甘薯渣同步糖化发酵生产酒精的工艺优化

    Institute of Scientific and Technical Information of China (English)

    王贤; 张苗; 木泰华

    2012-01-01

    To comprehensive utilize sweet potato starch industrial waste residue, simultaneous saccharification and fermentation (SSF) method was optimized to produce alcohol using sweet potato residue. Plackett-Burman design was used to select significant factors among 9 factors which had influenced on alcohol fermentation. Based on the selected results, steepest ascent method was used to approach the optimal region and response surface methodology was adopted to identify optimal values of significant factors. The results indicated that the effects of glucoamylase, inoculation ratio and fermentation temperature on alcohol fermentation was significant (P<0.05). The optimal conditions for alcohol fermentation were as follows: α-amylase 8 U/g, liquefying time 1.5 h, liquefying temperature 90℃, mass fraction of ammonium sulfate 0.15 g/100 g, pH value 4, fermentation time 36 h, glucoamylase 151 U/g, inoculation ratio 0.3% and fermentation temperature 36℃. Under the optimum conditions, alcohol concentration was 17.15%, which was close to theoretical predicted value( 16.95%). The optimum technology provides reference for the alcohol production technology by SSF method for sweet potato residue.%为了综合利用甘薯淀粉工业废渣,本研究以甘薯渣为原料发酵生产酒精,并对其同步糖化发酵工艺(SSF)进行优化.研究同步糖化发酵时影响酒精发酵工艺的9个因素,采用Plackett-Burman试验设计筛选出显著因素,并在筛选结果的基础上,用最陡爬坡途径逼近最大响应区域,然后利用响应面分析法确定其最佳参数.结果表明,影响洒精发酵工艺的显著因素为糖化酶、接种量和发酵温度.酒精发酵优化最佳参数为:α-淀粉酶8 U/g,液化时间1.5 h,液化温度90℃,硫酸铵质量分数0.15 g/100g,pH值4,发酵时间36 h,糖化酶151 U/g,接种量0.3%,发酵温度36℃.在此条件下,验证试验得到的酒精体积分数达到17.15%,接近理论预测值16.95%.优化后的工

  15. Brettanomyces yeasts--From spoilage organisms to valuable contributors to industrial fermentations.

    Science.gov (United States)

    Steensels, Jan; Daenen, Luk; Malcorps, Philippe; Derdelinckx, Guy; Verachtert, Hubert; Verstrepen, Kevin J

    2015-08-03

    Ever since the introduction of controlled fermentation processes, alcoholic fermentations and Saccharomyces cerevisiae starter cultures proved to be a match made in heaven. The ability of S. cerevisiae to produce and withstand high ethanol concentrations, its pleasant flavour profile and the absence of health-threatening toxin production are only a few of the features that make it the ideal alcoholic fermentation organism. However, in certain conditions or for certain specific fermentation processes, the physiological boundaries of this species limit its applicability. Therefore, there is currently a strong interest in non-Saccharomyces (or non-conventional) yeasts with peculiar features able to replace or accompany S. cerevisiae in specific industrial fermentations. Brettanomyces (teleomorph: Dekkera), with Brettanomyces bruxellensis as the most commonly encountered representative, is such a yeast. Whilst currently mainly considered a spoilage organism responsible for off-flavour production in wine, cider or dairy products, an increasing number of authors report that in some cases, these yeasts can add beneficial (or at least interesting) aromas that increase the flavour complexity of fermented beverages, such as specialty beers. Moreover, its intriguing physiology, with its exceptional stress tolerance and peculiar carbon- and nitrogen metabolism, holds great potential for the production of bioethanol in continuous fermentors. This review summarizes the most notable metabolic features of Brettanomyces, briefly highlights recent insights in its genetic and genomic characteristics and discusses its applications in industrial fermentation processes, such as the production of beer, wine and bioethanol. Copyright © 2015. Published by Elsevier B.V.

  16. [The total-quality-management-analysis of the continuation and discontinuation of alcohol family treatment: a grassroots approach].

    Science.gov (United States)

    Nishikawa, K; Tatsuki, S

    2001-06-01

    A family support/treatment program was provided to thirty-three cases where a drinking family member (identified patient) had shown alcohol related problems but not yet admitted the problem. After a period of between thirteen and twenty-one months of family treatment, fourteen (42.4%) identified patients started their own treatment. The only statistically significant factor that was related to the patients' treatment program participation was the continuation of family members' involvement in a family treatment program. Among the thirty-three cases, a little less than one half (48.5%) continued the family program. In order to increase the patients' participation, it is crucial to encourage family members to continue their family support/treatment program. In order to identify factors that contribute treatment continuation as well as dropouts, workshops were held with those who dropped out and those who continued the family treatment program. The Total-Quality-Management (TQM) affinity and arrow diagram techniques were employed to classify the participants' statements and to find cause-effect relationships among the identified factors, respectively. Five family treatment discontinuation factors were identified: 1) a lack of information about family support program, 2) resistance against a "family change" orientation in family treatment program, 3) family member burnout, 4) a misfit between family needs for immediate problem solutions and what family program offers, and 5) a temporal improvement of patients' drinking problems. While widely varied factors were found to contribute discontinuation, only a very few factors were identified to facilitate the treatment continuation. It was concluded that treatment discontinuation, rather than continuation, was the norm among the families of problem drinkers. Based on the above findings, three kaizen plans were proposed. First, in order to make sure that family members obtain necessary information about the family support

  17. 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.

    Science.gov (United States)

    Kemsawasd, Varongsiri; Branco, Patrícia; Almeida, Maria Gabriela; Caldeira, Jorge; Albergaria, Helena; Arneborg, Nils

    2015-07-01

    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 by cellulose membranes with different pore sizes, i.e. 1000 kDa for mixed- and single-culture fermentations, and 1000 and 3.5-5 kDa for compartmentalized-culture fermentations. SDS-PAGE and gel filtration chromatography were used to determine an antimicrobial peptidic fraction in the fermentations. Our results showed comparable amounts of the antimicrobial peptidic fraction in the inner compartments of the mixed-culture and 1000 kDa compartmentalized-culture fermentations containing L. thermotolerans after 4 days of fermentation, but a lower death rate of L. thermotolerans in the 1000 kDa compartmentalized-culture fermentation than in the mixed-culture fermentation. Furthermore, L. thermotolerans died off even more slowly in the 3.5-5 kDa than in the 1000 kDa compartmentalized-culture fermentation, which coincided with the presence of less of the antimicrobial peptidic fraction in the inner compartment of that fermentation than of the 1000 kDa compartmentalized-culture fermentation. Taken together, these results indicate that the death of L. thermotolerans in mixed cultures with S. cerevisiae is caused by a combination of cell-to-cell contact and antimicrobial peptides. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. 一株原生质体融合菌株发酵菊芋生产酒精的工艺条件优化%Optimization of Alcoholic Fermentation of a Protoplast Fusion Strain from Jerusalem Artichoke

    Institute of Scientific and Technical Information of China (English)

    张秀兰; 李雪雁; 张维

    2011-01-01

    The fusant strain called R8 which can secrete inulinase and produce alcohol was chosen to optimize the alcoholic fermentation in order to get high-yielding alcohol fermentation conditions. The optimum condition confmned through six single factor experimen%将试验筛选的具有分泌菊粉酶和产乙醇性能的融合菌株R8进行酒精发酵条件优化,经过6个单因素试验和正交试验,得到的优化条件为:160g/LJAE(菊芋提取液),25g/LBE(牛肉膏),8g/LNH4H2PQ4,0.1g/LZnCl2,pH6.0,30℃,转速180r/min。最终酒精得率为46.30%,原料糖分利用率能达到84.96%。

  19. Monascus-fermented red mold dioscorea protects mice against alcohol-induced liver injury, while its metabolites ankaflavin and monascin regulates ethanol induced PPAR-γ and SREBP-1 expression in HepG2 cells.

    Science.gov (United States)

    Cheng, Chih-Fu; Pan, Tzu-Ming

    2017-09-13

    Alcoholic hepatitis is a necroinflammatory process that is associated with fibrosis and leads to cirrhosis in 40% of cases. The hepatoprotective effects of red mold dioscorea (RMD) from Monascus purpureus NTU 568 were evaluated in vivo using a mouse model of chronic alcohol-induced liver disease (ALD). ALD mice were orally administered vehicle (ALD group) or vehicle plus 307.5, 615.0, or 1537.5 mg kg(-1) (1×, 2×, and 5×) RMD for 5 weeks. RMD lowered serum leptin, hepatic total cholesterol, free fatty acid, and hepatic triglyceride (TG) levels, and increased serum adiponectin, hepatic alcohol dehydrogenase, and antioxidant enzyme levels. Furthermore, ankaflavin (AK) and monascin (MS), metabolites of RMD fermented with M. purpureus 568, induced peroxisome proliferator-activated receptor (PPAR)-γ expression and the concomitant suppression of ethanol-induced elevation of sterol regulatory element-binding transcription factor (SREBP)-1 and TG in HepG2 cells. These results indicated the hepatoprotective effect of Monascus-fermented RMD. Moreover, AK and MS were identified as the active constituents of RMD for the first time, and were shown to protect against ethanol-induced liver damage. This article is protected by copyright. All rights reserved.

  20. Application of Acid-free Fermentation Using Compound Enzymes in the Production of Molasses Alcohol%发酵复合酶无酸发酵技术在糖蜜酒精生产中的应用

    Institute of Scientific and Technical Information of China (English)

    黄衡; 唐明

    2015-01-01

    酶制剂成功用于糖蜜酒精发酵生产,不但可以实现无酸化发酵,同时在多种酶制剂协同作用下,分解胶体物质,降低黏度,减少泡沫及醪塔结垢。在国家实行节能减排政策的今天,采用酶制剂无酸发酵将能大大提高糖蜜酒精生产效率,降低废水处理难度,是糖蜜酒精进行技术转型的方向。%The successful use of enzyme preparations in the production of molasses alcohol could not only achieve acid-free fermentation, but also simultaneously decompose colloidal substances, reduce viscosity, reduce bubbles and mash tower’s scale under the synergistic actions of multiple enzyme preparations. Under the background of the implementation of national policy of energy-saving and emission-reduction, the use of enzyme preparations for acid-free fermentation will greatly improve the production efficiency of molasses alcohol, and decrease the difficul-ty in waste-water treatment, which is the direction for technical transformation in molasses alcohol production.

  1. Effect of supplementing orchardgrass herbage with a total mixed ration or flaxseed on fermentation profile and bacterial protein synthesis in continuous culture.

    Science.gov (United States)

    Soder, K J; Brito, A F; Rubano, M D

    2013-05-01

    A 4-unit dual-flow continuous culture fermentor system was used to evaluate the effects of supplementing fresh herbage with a total mixed ration (TMR) or flaxseed on nutrient digestibility, fermentation profile, and bacterial N synthesis. Diets were randomly assigned to fermentors in a 4 × 4 Latin square design. Each fermentor was fed a total of 70 g of dry matter/d of 1 of 4 diets: (1) 100% freeze-dried orchardgrass herbage (Dactylis glomerata L.; HERB), (2) 100% freeze-dried TMR (100TMR), (3) 50% orchardgrass herbage supplemented with 50% TMR (50TMR), or (4) 90% orchardgrass herbage supplemented with 10% ground flaxseed (Linum usitatissimum L.; FLAX). Preplanned, single degree of freedom orthogonal contrasts were constructed to assess the effects of feeding system (HERB vs. 100TMR), herbage supplementation (HERB vs. 50TMR + FLAX), and herbage supplemental source (50TMR vs. FLAX). Compared with the HERB diet, the 100TMR diet significantly reduced apparent digestibility of neutral detergent fiber. Herbage supplementation with 50TMR or FLAX significantly reduced or tended to reduce apparent digestibilities of dry matter, organic matter, and neutral detergent fiber, suggesting that replacing high-quality, highly digestible fresh herbage with forage TMR likely caused depressions in nutrient digestibilities. Concentration of total volatile fatty acids, molar proportions of acetate, propionate, and isovalerate, as well as the acetate:propionate ratios were all significantly higher in fermentors fed 100TMR compared with HERB, likely in response to enhanced supply of fermentable energy. In general, feeding system, herbage supplementation, and type of supplementation did not affect N metabolism in the present study. The few significant changes in N metabolism (e.g., flows of total N and non-NH3-N) were primarily linked to increased fermentor N supply with feeding herbage-based diets (HERB and FLAX). Although TMR-based diets decreased nutrient digestibility slightly, TMR

  2. Effects of saponins, quercetin, eugenol, and cinnamaldehyde on fatty acid biohydrogenation of forage polyunsaturated fatty acids in dual-flow continuous culture fermenters.

    Science.gov (United States)

    Lourenço, M; Cardozo, P W; Calsamiglia, S; Fievez, V

    2008-11-01

    Four different plant secondary metabolites were screened for their effect on rumen biohydrogenation of forage long-chain fatty acids, using dual-flow continuous culture fermenters. Treatments were as follows: control (no additive), positive control (12 mg/L of monensin), and plant extracts (500 and 1,000 mg/L of triterpene saponin; 250 and 500 mg/L of quercetin; 250 mg/L of eugenol; 500 mg/L of cinnamaldehyde). Monensin increased propionate, decreased acetate and butyrate proportions, and inhibited the complete biohydrogenation of fatty acids resulting in the accumulation of intermediates of the biohydrogenation process (C18:2 trans-11, cis-15 rather than C18:1 trans-11). Cinnamaldehyde decreased total VFA concentration and proportions of odd and branched-chain fatty acids in total fat effluent. Apparent biohydrogenation of C18:2n-6 and C18:3n-3 was also less, and a shift from the major known biohydrogenation pathway to a secondary pathway of C18:2n-6 was observed, as evidenced by an accumulation of C18:1 trans-10 and trans-10, cis-12 CLA. Quercetin (500 mg/L) increased total VFA concentration, but no shifts in the pathways or extent of biohydrogenation were observed. Eugenol resulted in the accumulation of C18:1 trans-15 and C18:1 cis-15, end products of an alternative biohydrogenation pathway of C18:3n-3. Triterpene saponins did not affect the fermentation pattern, the biohydrogenation pathways, or the extent of biohydrogenation. At the doses tested in this study, we could only show a direct relation between changes in the rumen fatty acid metabolism and the presence of cinnamaldehyde but not for eugenol, quercetin, or triterpene saponins.

  3. Continuous transformation of benzaldehyde to benzyl alcohol by Rhodotorula mucilaginosa immobilized in an ultrafiltration cell

    Energy Technology Data Exchange (ETDEWEB)

    Wisniewski, J.; Winnicki, T.; Majewska, K.

    1982-06-01

    Microbiological transformation of benzaldehyde accomplished by the fungus Rhodotorula mucilaginosa immobilized in the ultrafiltration cell was studied. A polysulfone membrane formed on a sintered PVC support was used for the separation of the transformation product from the cellular material. Kinetic investigations have led to results which are typical of continuously fed stirred tank reactors (CFSTR)-the value of the maximum reaction rate (Vmax) and apparent Michaelis constant (K'm) are practically independent of the substrate retention time (calculated in terms of the flow intensity value). A strong relationship was found to occur between Vmax and biomass concentration in the reactor. Study of the apparent enzyme stability shows that the decrease in the biocatalyst activity is chiefly caused by penetration of the cells through the membrane. The experimental results were approximated in terms of the adopted mathematical model. Based on this model, the half-lives (t1/2) of enzyme activities were determined. The t1/2 value varies from 35 to 82 days and depends both on the permeate flux through the membrane and on the separation properties of the membrane. (Refs. 15).

  4. Effect of feeding warm-season annuals with orchardgrass on ruminal fermentation and methane output in continuous culture

    Science.gov (United States)

    A 4-unit, dual-flow continuous culture fermentor system was used to assess nutrient digestibility, volatile fatty acids (VFA) production, bacterial protein synthesis and CH4 output of warm-season summer annual grasses. Treatments were randomly assigned to fermentors in a 4 × 4 Latin square design us...

  5. Effect of incremental flaxseed supplementation of an herbage diet on methane output and ruminal fermentation in continuous culture

    Science.gov (United States)

    A 4-unit dual-flow continuous culture fermentor system was used to assess the effect of increasing flax supplementation of an herbage-based diet on nutrient digestibility, bacterial N synthesis and methane output. Treatments were randomly assigned to fermentors in a 4 x 4 Latin square design with 7 ...

  6. Continuous fermentation of food waste leachate for the production of volatile fatty acids and potential as a denitrification carbon source.

    Science.gov (United States)

    Kim, Hakchan; Kim, Jaai; Shin, Seung Gu; Hwang, Seokhwan; Lee, Changsoo

    2016-05-01

    This study investigated the simultaneous effects of hydraulic retention time (HRT) and pH on the continuous production of VFAs from food waste leachate using response surface analysis. The response surface approximations (R(2)=0.895, pwaste-derived VFAs, an alternative carbon source for denitrification.

  7. 基于ARM-Linux的酒精发酵远程监控系统的设计与实现%Design and implementation of alcohol fermentation remote monitoring system based on ARM-Linux

    Institute of Scientific and Technical Information of China (English)

    郭鹏飞; 齐跃; 李朝阳; 张建伟

    2012-01-01

    The current alcohol fermentation was supervisory controled mainly by using singlechip and had disadvantages such as backward function,small montioring range and inconvenient information circulation feedback. A remote monitoring system was designed. In this system, the data of pH value and temperature etc were collected and processed based on ARM platform and Linux operation system. The data were also transmitted from alcohol fermentation equipment to host machine using TCP/IP protocol, at the same time it supports remote client to control through the Web, so the remote monitoring was reached for alcohol fermentation equipment. The test results showed that the program broadens the scope of monitoring,and it has a good application prospect.%针对目前酒精发酵主要使用单片机进行实地监控,其功能落后、监控范围小、信息流通反馈不便等问题,设计了一个远程监控系统.该系统采用ARM平台和Linux操