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

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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.

Continuous cider fermentation with co-immobilized yeast and Leuconostoc oenos cells.

Science.gov (United States)

Nedovic; Durieuxb; Van Nedervelde L; Rosseels; Vandegans; Plaisant; Simon

2000-06-01

Ca-alginate matrix was used to co-immobilize Saccharomyces bayanus and Leuconostoc oenos in one integrated biocatalytic system in order to perform simultaneously alcoholic and malo-lactic fermentation of apple juice to produce cider, in a continuous packed bed bioreactor. The continuous process permitted much faster fermentation compared with the traditional batch process. The flavor formation was also better controlled. By adjusting the flow rate of feeding substrate through the bioreactor, i.e. its residence time, it was possible to obtain either "soft" or "dry" cider. However, the profile of volatile compounds in the final product was modified comparatively to the batch process, especially for higher alcohols, isoamylacetate, and diacetyl. This modification is due to different physiology states of yeast in two processes. Nevertheless, the taste of cider was quite acceptable.

Technology and economics of fermentation alcohol - an update

Energy Technology Data Exchange (ETDEWEB)

Carroll, R.K.

1983-03-01

Fermentation alcohol is being widely studied as an alternative fuel, and production is increasing, especially in Brazil, where the goal is more than 10 billion litres per year by 1985. Fuel markets are hundreds of times greater than the traditional ethanol markets which the existing industry supplies. To make a material contribution to fuel supply, fermentation ethanol must be treated as a major chemical and produced in large-volume, highly efficient plants. Such plants must be assured of a continuous supply of low-cost raw materials for which suitable processes have been developed and commercially proven. Sugar cane in the tropics and grains in some temperate countries meet these requirements; cellulosics do not qualify at present, nor will they in the foreseeable future, without major breakthroughs. Using techniques borrowed from the starch sweetener industry, starchy materials may be economically hydrolysed to fermentable sugars; rapid acid hydrolysis may prove superior to enzymatic processes. Major projects are under way to replace traditional batch or cascade fermentations with rapid, single-vessel continuous units, but these have not yet been fully proven. Where suitable, yeast recycle is being used as a means of increasing alcohol yields, and energy-efficient distillation methods of the petrochemical industry are being adopted. The consequent large reduction in steam consumption greatly reduces the appeal of other methods which have been proposed to remove water. Opportunities for process improvements abound, especially in developing (1) the means to provide cellulosic raw materials in large quantities at acceptable costs, (2) economically effective methods of pretreating and hydrolysing cellulosics, (3) practical organisms for converting five-carbon sugars to ethanol and (4) higher fermentation yields and efficiencies using bacteria or immobilized yeast. (Refs. 21).

Improved fermentative alcohol production. [Patent application

Science.gov (United States)

Wilke, C.R.; Maiorella, B.L.; Blanch, H.W.; Cysewski, G.R.

1980-11-26

An improved fermentation process is described for producing alcohol which includes the combination of vacuum fermentation and vacuum distillation. Preferably, the vacuum distillation is carried out in two phases, one a fermentor proper operated at atmospheric pressure and a flash phase operated at reduced pressure with recycle of fermentation brew having a reduced alcohol content to the fermentor, using vapor recompression heating of the flash-pot recycle stream to heat the flash-pot or the distillation step, and using water load balancing (i.e., the molar ratio of water in the fermentor feed is the same as the molar ratio of water in the distillation overhead).

Industrial alcohol production via whey and grain fermentation

Energy Technology Data Exchange (ETDEWEB)

Friend, B A; Cunningham, M L; Shahani, K M

1982-01-01

Six strains of a trained lactose fermenting Kluyveromyces yeast were examined for their ability to utilise lactose in sweet-whey permeate. All strains of K. fragilis tested reduced the concentration of the 5.1% lactose, initially present in whey permeate, to 0.1-0.2% within 48h. Periodic adjustment to maintain the pH during fermentation did not alter the lactose utilisation. The fermentation efficiency of K. fragilis was then compared with that of a mixture of K. fragilis and the classical alcohol fermenter Saccharomyces cerevisiae to verify that no unfavourable interactions occurred in the mixed culture. There were no differences in lactose utilisation or ethanol production between the two groups; both produced approximately 2% ethanol within 24h. This represented approximately 80% of the alcohol which theoretically could be produced from the 5.1% lactose present in the permeate. Whey permeate was also incorporated into the classical grain fermentation by substitution for one-half the water normally added to produce the mash. Fermentation was nearly complete by 36h and alcohol levels ranged from 9.7% for the mixed culture to 9.4% for the K. fragilis and 9.3% for the S. cerevisiae. Since the whey provided significant levels of fermentable sugars, studies were also conducted in which undiluted whey permeate was substituted for all of the water in the mash and the amount of grain was reduced by 20%. At the end of 36h K. fragilis produced 10.9% alcohol and at 60 h of fermentation the level had reached 12.2%. When whole sweet-whey was used, similar levels of alcohol were produced. (Refs. 20).

Fermentative Alcohol Production

DEFF Research Database (Denmark)

Martín, Mariano; Sánchez, Antonio; Woodley, John M.

2018-01-01

In this chapter we present some of key principles of bioreactor design for the production of alcohols by fermentation of sugar and syngas . Due to the different feedstocks, a detailed analysis of the hydrodynamics inside the units , bubble columns or stirred tank reactors , the gas-liquid mass...

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.

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

KAUST Repository

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

2014-01-01

© 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

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.

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

OpenAIRE

Spinosa,Wilma Aparecida; Santos Júnior,Vitório dos; Galvan,Diego; Fiorio,Jhonatan Luiz; Gomez,Raul Jorge Hernan Castro

2015-01-01

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 vineg...

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 and...

Hybridization of halotolerant yeast for alcohol fermentation

International Nuclear Information System (INIS)

Limtong, S.

1991-01-01

Attempt have been made to construct a new yeast strain from alcohol fermenting strains and salt tolerant strains. It is anticipated that the new yeast strain will be able to ferment alcohol in molasses mash with high salinity, up to 3% of NaCl. Another characteristics is its ability to tolerate up to 40 C temperature which is desirable for alcohol fermentation in tropical countries. Commercial and wild strains of Saccharomyces cerevisiae were screened for their fermenting ability and strain SC90, 191 TJ3, and AM12 were selected as parental strains for fusion among themselves and with other halo tolerant species. Halo tolerant strains selected at 5% NaCl in molasses mash were tentatively identified as Torulopsis grabrata, T. candida, T. Bovina and S. Rouxii whereas all of those strains selected at 17% NaCl were Citeromyces sp. It was found that fusant TA73 derived from wild strain and sake fermenting strain performed best among 4,087 fusants investigated. This fusant fermented much better than their parental strains when salt concentrations were increased to 5 and 7% NaCl. Experiment was carried out in fermentor, 1.5 liter working volume using molasses mash with 3% NaCl and temperature was controlled at 35 degree C. Fermentation rate of TA73, TJ3 and AM12 were 2.17, 1.50 and 1.87 g/L/hr respectively, Maximum ethanol concentration obtained were 7.6, 6.7 and 7.4% by weight after 60 and 78 hours respectively. Other fusants derived from fusion of Saccharomyces cerevisiae with other halo tolerant species were mostly inferior to their parental strains and only 7 fusants were slightly better than parental strains. (author)

Alcoholic fermentation of whey

Energy Technology Data Exchange (ETDEWEB)

Beach, A S; Holland, J W

1958-09-10

The lactose of whey and other milk products is rapidly fermented to ethanol by means of Candida pseudotropicalis strain XI. The fermentation is complete in about 12 hours and yields about 45% ethanol based on the weight of lactose. Conditions favoring the fermentation and inhibiting lactic acid production include pH 4.5, 30/sup 0/, and continuous aeration.

Increasing alcohol yield in sugar fermentation

Energy Technology Data Exchange (ETDEWEB)

Colin, P

1962-02-20

The yield of alcohol from yeast fermentations of sugar solutions is increased 1.5 to 5% by the addition of 0.1 to 0.5 parts by volume of a monohydric saturated aliphatic alcohol of at least 6 C atoms in a straight chain such as hexanol or heptanol, or branched chain, such as 2-ethylbutanol or 2-ethylhexanol, or a mixture consisting mostly of C/sub 7/, C/sub 8/, C/sub 9/, or C/sub 10/ alcohols.

Continuous fermentation of whey into alcohol using an attached film expanded bed reactor

Energy Technology Data Exchange (ETDEWEB)

Chen, H C; Zall, R R

1982-01-01

Batch and continuous processes were studied using a lactose- fermenting yeast, Saccharomyces fragi. Batch methods were used to study the effects of temperature, pH, yeast extract, and ergosterol on ethanol and cell mass production. The optimal temperature ranged from 32 to 37 degrees C. No pH control appeared necessary for whey fermentation. Supplements of yeast extract and ergosterol appeared to have pronounced effect on cell mass and ethanol production. Overall, whey reconstituted from acid whey powder containing 10% lactose could be converted to 36.5 g/l of ethanol in 44 hours when the material was supplemented with 0.7% yeast extract, 10 mg/l ergosterol, and fermented at 32 degrees C using 2.67% aerobically grown inoculum containing approximately 110 x 10 to the power of 6 CFU/ml. Ethanol productivity as high as 6.9 g/lj/h was achieved in a continuous attached film expanded bed fermentor using cellulose acetate as support media. The retention time was 1.1 hour and effluent ethanol concentration was 7.6 g/l. (Refs. 27).

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

International Nuclear Information System (INIS)

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

2017-01-01

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

Profile of the alcohols produced in fermentations with malt contaminated with trichothecenes

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Reinehr Christian Oliveira

2003-01-01

Full Text Available In order to study the influence of mycotoxins on the production of alcohols, a fermentative process on a laboratorial scale was simulated. Malt was contaminated with deoxynivalenol and T-2 in different ratios (up to 500 ppb, according to a 3² factorial design, and the alcohols obtained after the fermentation were determined through gas chromatography. The results showed that trichothecenes influenced the profile of the alcohols produced by Saccharomyces cerevisiae during the fermentative process of malt, especially the profile of methyl and isoamyl alcohols.

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. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The state-of-the-art and forecasts for alcoholic fermentation in Brazil; Estado atual e perspectivas da fermentacao alcoolica no Brasil

Energy Technology Data Exchange (ETDEWEB)

Rossell, Carlos Eduardo Vaz; Carvalho Macedo, Isaias de [Centro de Tecnologia Copersucar, Piracicaba, SP (Brazil)

1988-12-31

The state-of-the-art of the alcoholic fermentation for fuel alcohol production in Brazil shows that besides the great increase in production in the last twelve years, a significant advance in technology was achieved, both in the traditional batch fermentation (increased yields and productivity) and in the new large-scale multi-stage continuous fermentations. Large differences in technology level among distilleries show the need for improving technology transfer rates. Examples are presented and analyzed. (author) 7 figs., 5 tabs.

Determination of expected alcohol yield from molasses by laboratory fermentation

Energy Technology Data Exchange (ETDEWEB)

Medintseva, L L

1960-01-01

Molasses (750 g, 18 to 19% dry weight) in 31 media, supplemented with nutrients was fermented with the industrial yeast strain. The expected alcohol yield was calculated for 1 kg conventional starch as B = V/P..pi.. 0.95, where V is the amount of alcohol distilled from the fermented medium in ml, P is the weight of molasses in g, is the fermentable sugar content of the molasses in percent, and 0.95 is the conversion factor from sucrose to starch.

Studies on continuous fermentation

Energy Technology Data Exchange (ETDEWEB)

Ueda, K

1958-01-01

Continuous fermentation of molasses with a combined system of agitated vessel and flow pipe is studied. A new apparatus was designed. The rate of the fermentation was faster with this apparatus than with the former apparatus which was composed of two vessels.

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

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Berta Carola Pérez

2004-07-01

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.

Application of butyl alcohol bacteria for the fermentation of nonnutritive raw materials

Energy Technology Data Exchange (ETDEWEB)

Nakhamanovich, B M; Senkevich, V V; Yarovenko, V L

1961-01-01

Materials like corncobs after hydrolysis can be economically fermented by using bacteria which support a butyl alcohol-acetone fermentation. Best results are obtained if (NH/sub 4/)/sub 2/SO/sub 4/ and superphosphate are added to the fermentation liquor. Analyses are presnted of the hydrolzates (alcohols, formic acid, 2-furaldehyde, and reducing sugars) and of the final products.

Fermentation of starches and sugars to alcohol

Energy Technology Data Exchange (ETDEWEB)

Fertman, G I; Berenshtein, A F; Gulyaev, J P

1958-02-25

To prevent the growth of acid-forming bacteria in the started wort, the ester-aldehyde fraction or the amino alcohol obtained in the rectification process is returned to the wort in amounts sufficient to give an alcohol concentration of approximately 1.5% by volume. The fermenting wort is also acidified to 0.5 to 0.6.

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.

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; Koh, Eunmi

2015-09-01

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.

Irradiation effects on the alcohol fermentation ability of saccharomyces cerevisiae

International Nuclear Information System (INIS)

Sadi, Suharni

1987-01-01

Irradiation effects on the alcohol fermentation ability of saccharomyces cerevisiae. S. cerevisiae suspensions of 1.5x10 8 clls/ml were exposed to single and fractionated doses of gamma irradiation, i.e. 0; 0.30; 0.60; 0.90; and 1.20 kGy in aerobic condition at dose rate of 1.63 kGy/hour. The fractionated doses were given with time interval of 15, 30 and 45 minutes. The fermentation was held at 30 0 C for 40 hours. It is seen that an increase of alcohol production was obtained when cells were irradiated at 0.60 kGy, although the result has no significant difference statistically with control. At the dose of 1.20 kGy the alcohol fermentation ability of S. cerevisiae decreased drastically as compared to control. Irradiation using single or fractionated doses with time interval of 15-45 minutes did not influence the alcohol production. Comparing the time interval of 45 minutes at 0.60 kGy and at 1.20 kGy, it appeared that the yield of alcohol was different. (author). 17 refs.; 4 figs

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.

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

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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.

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

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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.

Kinetic study of an alcoholic fermentation, using honey like substrate

International Nuclear Information System (INIS)

Gomez, Jose Angel; Castano, Hader Ivan; Arias Mario

1997-01-01

The paper describes a kinetic study of an alcoholic fermentation using honey like substrate; for this effect they were carried out nine fermentations in discontinuous process with a volume, of 10 L, following the behavior of the substrate concentrations, biomass and product in the time. It was evaluated the convenience of factors like the agitation and the addition of nutritious, also, it was observed the effect of the initial concentrations of substrate and inoculate and the type of honey looking for the best conditions of the process for the obtaining of an alcoholic drink

Accumulation of Citrulline by Microbial Arginine Metabolism during Alcoholic Fermentation of Soy Sauce.

Science.gov (United States)

Fang, Fang; Zhang, Jiran; Zhou, Jingwen; Zhou, Zhaohui; Li, Tieqiao; Lu, Liling; Zeng, Weizhu; Du, Guocheng; Chen, Jian

2018-03-07

Citrulline, the major precursor of ethyl carbamate in soy sauce, is an intermediate catabolite of arginine produced by bacteria present in soy sauce moromi mash. Pediococcus acidilactici is responsible for the formation of citrulline during the lactic acid fermentation process of soy sauce. However, citrulline accumulation during the alcoholic fermentation process and the corresponding bacteria involved have not been identified. Salt-tolerant, arginine-utilizing bacteria were isolated from moromi mash during the alcoholic fermentation process. Under normal cultivation conditions, arginine utilization by these strains did not contribute to citrulline accumulation. However, the conversion of arginine to citrulline by these bacteria increased when cultivated during the alcoholic fermentation process. Additionally, the ethanol-enhanced solubility of free fatty acids in moromi mash stimulated the accumulation of citrulline. Staphylococcus exhibited the highest capability in the conversion of arginine to citrulline.

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.

Disappearance of patulin during alcoholic fermentation of apple juice.

Science.gov (United States)

Stinson, E E; Osman, S F; Huhtanen, C N; Bills, D D

1978-10-01

Eight yeast strains were used in three typical American processes to ferment apple juice containing 15 mg of added patulin per liter. Patulin was reduced to less than the minimum detectable level of 50 microgram/liter in all but two cases; in all cases, the level of patulin was reduced by over 99% during alcoholic fermentation. In unfermented samples of apple juice, the concentration of added patulin declined by only 10% when the juice was held for 2 weeks, a period equivalent to the time required for fermentation.

Assessment of chemical and sensory quality of sugarcane alcoholic fermented beverage.

Science.gov (United States)

Resende Oliveira, Érica; Caliari, Márcio; Soares Soares Júnior, Manoel; Ribeiro Oliveira, Aryane; Cristina Marques Duarte, Renata; Valério de Barros Vilas Boas, Eduardo

2018-01-01

This study aimed to verify the technological feasibility, chemical quality and sensory acceptance of alcoholic fermented beverage obtained from sugarcane juice. A completely randomized design was applied. Sugar and alcohol content, phenolic (HPLC-MS) and volatile (GS-MS) compounds, pH, density, dry matter and acidity of the fermented beverage of sugarcane were quantified, as well as the acceptance of the product was carried out. The complete fermentation of sugarcane lasted 7 days, and it was obtained an alcohol content of 8.0% v/v. Titrable acidity of the beverage was of 67.31 meq L -1 , pH 4.03, soluble solids of 5 °Brix, reducing sugar of 0.07 g glucose 100 g -1 , density of 0.991 g cm -3 , reduced dry matter of 14.15 g L -1 , sulfates lower than 0.7 g K 2 SO 4  L -1 . Various phenolic compounds, among which, gallic acid (10.97%), catechin (1.73%), chlorogenic acid (3.52%), caffeic acid (1.49%), vanillic acid (0.28%), p -coumaric acid (0.24%), ferulic acid (6.63%), m -coumaric acid (0.36%), and o -coumaric acid (0.04%). Amongst aromatic compounds, were found mainly esters with fruity aromas (ethyl ester hexanoic acid and ethyl ester octanoic acid). The sugarcane juice can be commercialized as an alternative wine, as it presented adequate features to an alcoholic fermented beverage and was sensory accepted by consumers.

Study on yeast mutant with high alcohol yield fermented in sweet sorghum juice using carbon ion irradiation

International Nuclear Information System (INIS)

Yan Yaping; Lu Dong; Wang Jufang; Dong Xicun; Gao Feng; Ma Liang; Li Wenjian

2009-01-01

Five mutants with high ability of producing alcohol were selected out by using TTC as an indicator after irradiation of the alcohol yeast with 100 MeV/u carbon ions. The fermentation experiment in sweet sorghum juice showed that the alcohol production ability of mutant T4 strain increased 18.6% compared to the control strain. The residual sugar content in the juice was decreased too. After that,the optimum fermentation conditions of the T4 strain in sweet sorghum juice were investigated. The results showed that the optimum temperature and pH value for fermentation were 30 degree C and 4.5, respectively. The verification experiment was fermented in a 10 l bio-reactor and the obtained data indicated that the fermentative rate and the ability of producing alcohol in T4 strain was higher than that in the control strain under the same fermentation condition. (authors)

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...... 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...... 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 wine fermentations....

Cyclic method for the fermentation of starch raw material in the Romadanovsk alcohol plant

Energy Technology Data Exchange (ETDEWEB)

Naumenko, I I; Basharin, I I; Pol' gin, I V

1958-01-01

Fermentation vats (volume 32 cu.m.) were connected in 2 series of 4 vats communicating by flow pipes supplied with cut-off valves. The main wort conduit was supplied with a 3-way valve connected with a bent pipe joint, by means of which the 3-way valve could be turned to any of the vats. Fermentation took place alternately, each vat series being filled for 24 hours with wort after yeast had been added. Fermentation in the main vat continued for 38 hours and in the others for 20 hours. Draining the finished brew and the preparation of the vats for the next fermentation began from the 4th vat, which in the following cycle, became the main vat. Fermentation took place with satisfactory acidity-increase indexes (less than or equal to 0.20 D.), with wastes no greater than expected, and with an alcohol yield of 100.2 to 100.3% of that expected from 1 ton of starch. The advantages of the cyclic method are a decrease in the fermentation time and a more complete fermentation of sugar; the method can thus be recommended for fermentation plants which have an insufficient productivity as a method which does not require many repairs or much expense. A flow sheet of the process and the design of the distributing pipes are given.

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

OpenAIRE

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...

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

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

International Nuclear Information System (INIS)

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

2006-01-01

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

Decreased production of higher alcohols by Saccharomyces cerevisiae for Chinese rice wine fermentation by deletion of Bat aminotransferases.

Science.gov (United States)

Zhang, Cui-Ying; Qi, Ya-Nan; Ma, Hong-Xia; Li, Wei; Dai, Long-Hai; Xiao, Dong-Guang

2015-04-01

An appropriate level of higher alcohols produced by yeast during the fermentation is one of the most important factors influencing Chinese rice wine quality. In this study, BAT1 and BAT2 single- and double-gene-deletion mutant strains were constructed from an industrial yeast strain RY1 to decrease higher alcohols during Chinese rice wine fermentation. The results showed that the BAT2 single-gene-deletion mutant strain produced best improvement in the production of higher alcohols while remaining showed normal growth and fermentation characteristics. Furthermore, a BAT2 single-gene-deletion diploid engineered strain RY1-Δbat2 was constructed and produced low levels of isobutanol and isoamylol (isoamyl alcohol and active amyl alcohol) in simulated fermentation of Chinese rice wine, 92.40 and 303.31 mg/L, respectively, which were 33.00 and 14.20 % lower than those of the parental strain RY1. The differences in fermentation performance between RY1-Δbat2 and RY1 were minor. Therefore, construction of this yeast strain is important in future development in Chinese wine industry and provides insights on generating yeast strains for other fermented alcoholic beverages.

Alcoholic fermentation by immobilized yeast at high sugar concentrations

Energy Technology Data Exchange (ETDEWEB)

Holcberg, I.B.; Margalith, P.

1981-01-01

Glucose fermentation by Saccharomyces cerevisiae immobilized by entrapment in agar, carrageenan, alginate and polyacrylamide gels, was compared to that of freely suspended cells at concentration of 10-50% (w.w.) sugar. The rate of ethanol production by the entrapped cells was 20-25% higher than that of the free cells. Concentrations of up to 14.5% w/w ethanol (30% glucose initial concentration) could be obtained. A number of hypotheses for the improved alcoholic fermentation are discussed.

Inexpensive on-line alcohol sensor for fermentation monitoring and control

Energy Technology Data Exchange (ETDEWEB)

Birch, S W; Turner, A P.F.; Ashby, R E

1987-01-01

An inorganic electrochemical fuel cell sensor was interfaced to a microcomputer and used to measure on-line the alcohol concentration in the off-gas of a fermentor. A calibration curve was obtained for methanol (linear range 0-9 g/l) and ethanol (linear range 0-6 g/l) to relate the alcohol concentration in the fermentor liquid with that in the off-gas. The consumption of methanol in a batch fermentation of the methylotroph Ps.BB1 was monitored (sampling frequency of 5 minutes) and compared with samples taken for off-line analysis by GLC. On-line control of the methanol concentration in a fed-batch fermentation was achieved by proportional and integral control. 24 references.

Substituent effect of phenolic aldehyde inhibition on alcoholic fermentation by Saccharomyces cerevisiae

Science.gov (United States)

Rui Xie; Maobing Tu; Thomas Elder

2016-01-01

Phenolic compounds significantly inhibit microbial fermentation of biomass hydrolysates. To understand thequantitative structure-inhibition relationship of phenolic aldehydes on alcoholic fermentation, the effect of 11 differentsubstituted benzaldehydes on the final ethanol yield was examined. The results showed that the degree of phenolic...

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.

Open and continuous fermentation: products, conditions and bioprocess economy.

Science.gov (United States)

Li, Teng; Chen, Xiang-bin; Chen, Jin-chun; Wu, Qiong; Chen, Guo-Qiang

2014-12-01

Microbial fermentation is the key to industrial biotechnology. Most fermentation processes are sensitive to microbial contamination and require an energy intensive sterilization process. The majority of microbial fermentations can only be conducted over a short period of time in a batch or fed-batch culture, further increasing energy consumption and process complexity, and these factors contribute to the high costs of bio-products. In an effort to make bio-products more economically competitive, increased attention has been paid to developing open (unsterile) and continuous processes. If well conducted, continuous fermentation processes will lead to the reduced cost of industrial bio-products. To achieve cost-efficient open and continuous fermentations, the feeding of raw materials and the removal of products must be conducted in a continuous manner without the risk of contamination, even under 'open' conditions. Factors such as the stability of the biological system as a whole during long cultivations, as well as the yield and productivity of the process, are also important. Microorganisms that grow under extreme conditions such as high or low pH, high osmotic pressure, and high or low temperature, as well as under conditions of mixed culturing, cell immobilization, and solid state cultivation, are of interest for developing open and continuous fermentation processes. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Production of tea vinegar by batch and semicontinuous fermentation

OpenAIRE

Kaur, Pardeep; Kocher, G. S.; Phutela, R. P.

2010-01-01

The fermented tea vinegar combines the beneficial properties of tea and vinegar. The complete fermentation takes 4 to 5 weeks in a batch culture and thus can be shortened by semi continuous/ continuous fermentation using immobilized bacterial cells. In the present study, alcoholic fermentation of 1.0 and 1.5% tea infusions using Saccharomyces cerevisae G was carried out that resulted in 84.3 and 84.8% fermentation efficiency (FE) respectively. The batch vinegar fermentation of these wines wit...

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 %.

Purifying synthetic or fermentation ethyl alcohol

Energy Technology Data Exchange (ETDEWEB)

1958-10-22

Synthetic or fermentation grade ethanol is treated with an alkaki metal sulfite for about 10 hours then rectified to give a product free of odor and taste defects. For example, ethanol from molasses was treated with 10g Na/sub 2/SO/sub 3/.7H/sub 2/O per liter of alcohol, (70/sup 0/ Gay-Lussac) for 10 hours. Synthetic ethanol was treated with 3g Na/sub 2/SO/sub 3/.7H/sub 2/O for 10 hours.

Purifying synthetic or fermentation ethyl alcohol

Energy Technology Data Exchange (ETDEWEB)

1958-10-22

Synthetic or fermentation grade ethanol is treated with an alkali metal sulfite for about 10 hours then rectified to give a product free of odor and taste defects. For example, ethanol from molasses was treated with 10g, Na/sub 2/SO/sub 3/.7H/sub 2/0 per liter of alcohol, (70/sup 0/ Gay-Lussac) for 10 hours. Synthetic ethanol was treated with 3 g Na/sub 2/SO/sub 3/.7H/sub 2/O for 10 hours.

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).

Mutation and screening of high-alcoholic-yield yeast by HEPE and optimization of the fermentation condition

International Nuclear Information System (INIS)

Han Jingjing; Lu Jiangtao; Zhang Qin; Wang Yan; Fu Yujie; Wang Shilong; Fu Haiying

2011-01-01

The Saccharomyces Cerevisiae YE0 was mutated using high-energy-pulse-electron (HEPE) beam. After ethanol stress and determination of the alcohol yield by gas chromatograph, the mutant YF1 with high alcoholic yield was obtained. The results showed that under the optimized fermentation conditions (34 degree C as the fermentation temperature, 72 h as the fermentation time and 30% as the glucose concentration), the alcoholic yield of YF1 was 15.57% which was 58.23% higher than that of the original strain YE0 (9.84%) under the same conditions. The growth rate and lethal temperature of the mutant YF1 were obviously enhanced to the original strain YE0. The mutant YF1 has a great potential application in industrial production of alcohol. And it can also be used as the original strain for further mutagenesis to get the strain of higher alcoholic yield. (authors)

Alcohol for cellulosic material using plural ferments

Energy Technology Data Exchange (ETDEWEB)

Hoge, W H

1977-02-22

A process is described for producing ethanol (EtOH) from cellulosic materials by first hydrolyzing the material to sugars and then converting the sugars to alcohol by digestion and fermentation. Thus, fibrous cellulosic material obtained from municipal waste slurry was sterilized by autoclaving, followed by inoculation with Trichoderma viride cellulase and Saccharomyces cerevisiae. From 100 g of raw material, 25 mL of 95% EtOH was produced by this method.

Folpet hydrolysis - Incidence on the initiation of the alcoholic fermentation

Directory of Open Access Journals (Sweden)

Efimia Hatzidimitriou

1997-03-01

Full Text Available This note presents the first results of a work conducted on the future of the folpet grape must and the relationship between the behavior of the fungicide and the onset of fermentation alcoholic.

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).

Sensory profile and volatile aroma composition of reduced alcohol Merlot wines fermented with Metschnikowia pulcherrima and Saccharomyces uvarum.

Science.gov (United States)

Varela, C; Barker, A; Tran, T; Borneman, A; Curtin, C

2017-07-03

Strategies for production of wines containing lower alcohol concentrations are in strong demand, for reasons of quality, health, and taxation. Development and application of wine yeasts that are less efficient at transforming grape sugars into ethanol has the potential to allow winemakers the freedom to make lower alcohol wines from grapes harvested at optimal ripeness, without the need for post-fermentation processes aimed at removing ethanol. We have recently shown that two non-conventional wine yeast species Metschnikowia pulcherrima and Saccharomyces uvarum were both able to produce wine with reduced alcohol concentration. Both species produced laboratory-scale wines with markedly different volatile aroma compound composition relative to Saccharomyces cerevisiae. This work describes the volatile composition and sensory profiles of reduced-alcohol pilot-scale Merlot wines produced with M. pulcherrima and S. uvarum. Wines fermented with M. pulcherrima contained 1.0% v/v less ethanol than S. cerevisiae fermented wines, while those fermented with S. uvarum showed a 1.7% v/v reduction in ethanol. Compared to S. cerevisiae ferments, wines produced with M. pulcherrima showed higher concentrations of ethyl acetate, total esters, total higher alcohols and total sulfur compounds, while wines fermented with S. uvarum were characterised by the highest total concentration of higher alcohols. Sensorially, M. pulcherrima wines received relatively high scores for sensory descriptors such as red fruit and fruit flavour and overall exhibited a sensory profile similar to that of wine made with S. cerevisiae, whereas the main sensory descriptors associated with wines fermented with S. uvarum were barnyard and meat. This work demonstrates the successful application of M. pulcherrima AWRI3050 for the production of pilot-scale red wines with reduced alcohol concentration and highlights the need for rigorous evaluation of non-conventional yeasts with regard to their sensory impacts

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.

Comparative studies of citric acid, acetone-butanol, and alcohol fermentation processes in beet molasses from several sugar factories

Energy Technology Data Exchange (ETDEWEB)

Kovats, J; Zuckerind, Z

1963-01-01

Citric acid (I) fermentation is the most sensitive to volatile acids and coloring matter contents of molasses, and butanol fermentation, the least. Citric acid and alcohol production decrease as volatile acids and coloring matter increase, but this last factor has a favorable effect on the acetone-butanol fermentation. Molasses which are suitable for citric acid production are also suitable for alcohol but not always for acetone-butanol.

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.

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.

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. Copyright 2004 Wiley Periodicals, Inc.

Alcohol production from sterilized and non-sterilized molasses by Saccharomyces cerevisiae immobilized on brewer's spent grains in two types of continuous bioreactor systems

International Nuclear Information System (INIS)

Kopsahelis, Nikolaos; Bosnea, Loulouda; Bekatorou, Argyro; Tzia, Constantina; Kanellaki, Maria

2012-01-01

In this work an integrated cost effective system for continuous alcoholic fermentation of a cheap raw material (molasses) is described, involving yeast immobilized by a simple method on brewer's spent grains, able to ferment in the temperature range 30–40 °C, and two types of bioreactors, a Multistage Fixed Bed Tower (MFBT) and a Packed Bed reactor (PB). The MFBT bioreactor gave better results regarding ethanol concentration, productivity and conversion. Furthermore, the use of sterilized and non-sterilized molasses, fed in two similar MFBT bioreactors, showed that ethanol concentration (kg m −3 ) was significantly (p −3 at 35 °C and 44.2–48.2 kg m −3 at 40 °C), compared to sterilized molasses, where ethanol concentration ranged from 35.6 to 46.6 kg m −3 at 35 °C and 30.8–44.2 kg m −3 at 40 °C. During 32 days of continuous operation using non-sterilized molasses no contamination was observed. Industrialization of the proposed system seems to have a potential, mainly due to its high fermentation efficiency and the obtained high operational stability. -- Highlights: ► An integrated cost effective system for continuous alcoholic fermentation. ► Efficient conversion of non-sterilized molasses to ethanol. ► No need for additional treatments to prevent contamination. ► Results showed high fermentation efficiency and high operational stability.

Starmerella bombicola influences the metabolism of Saccharomyces cerevisiae at pyruvate decarboxylase and alcohol dehydrogenase level during mixed wine fermentation

Science.gov (United States)

2012-01-01

Background The use of a multistarter fermentation process with Saccharomyces cerevisiae and non-Saccharomyces wine yeasts has been proposed to simulate natural must fermentation and to confer greater complexity and specificity to wine. In this context, the combined use of S. cerevisiae and immobilized Starmerella bombicola cells (formerly Candida stellata) was assayed to enhance glycerol concentration, reduce ethanol content and to improve the analytical composition of wine. In order to investigate yeast metabolic interaction during controlled mixed fermentation and to evaluate the influence of S. bombicola on S. cerevisiae, the gene expression and enzymatic activity of two key enzymes of the alcoholic fermentation pathway such as pyruvate decarboxylase (Pdc1) and alcohol dehydrogenase (Adh1) were studied. Results The presence of S. bombicola immobilized cells in a mixed fermentation trial confirmed an increase in fermentation rate, a combined consumption of glucose and fructose, an increase in glycerol and a reduction in the production of ethanol as well as a modification in the fermentation of by products. The alcoholic fermentation of S. cerevisiae was also influenced by S. bombicola immobilized cells. Indeed, Pdc1 activity in mixed fermentation was lower than that exhibited in pure culture while Adh1 activity showed an opposite behavior. The expression of both PDC1 and ADH1 genes was highly induced at the initial phase of fermentation. The expression level of PDC1 at the end of fermentation was much higher in pure culture while ADH1 level was similar in both pure and mixed fermentations. Conclusion In mixed fermentation, S. bombicola immobilized cells greatly affected the fermentation behavior of S. cerevisiae and the analytical composition of wine. The influence of S. bombicola on S. cerevisiae was not limited to a simple additive contribution. Indeed, its presence caused metabolic modifications during S. cerevisiae fermentation causing variation in the gene

Starmerella bombicola influences the metabolism of Saccharomyces cerevisiae at pyruvate decarboxylase and alcohol dehydrogenase level during mixed wine fermentation

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Milanovic Vesna

2012-02-01

Full Text Available Abstract Background The use of a multistarter fermentation process with Saccharomyces cerevisiae and non-Saccharomyces wine yeasts has been proposed to simulate natural must fermentation and to confer greater complexity and specificity to wine. In this context, the combined use of S. cerevisiae and immobilized Starmerella bombicola cells (formerly Candida stellata was assayed to enhance glycerol concentration, reduce ethanol content and to improve the analytical composition of wine. In order to investigate yeast metabolic interaction during controlled mixed fermentation and to evaluate the influence of S. bombicola on S. cerevisiae, the gene expression and enzymatic activity of two key enzymes of the alcoholic fermentation pathway such as pyruvate decarboxylase (Pdc1 and alcohol dehydrogenase (Adh1 were studied. Results The presence of S. bombicola immobilized cells in a mixed fermentation trial confirmed an increase in fermentation rate, a combined consumption of glucose and fructose, an increase in glycerol and a reduction in the production of ethanol as well as a modification in the fermentation of by products. The alcoholic fermentation of S. cerevisiae was also influenced by S. bombicola immobilized cells. Indeed, Pdc1 activity in mixed fermentation was lower than that exhibited in pure culture while Adh1 activity showed an opposite behavior. The expression of both PDC1 and ADH1 genes was highly induced at the initial phase of fermentation. The expression level of PDC1 at the end of fermentation was much higher in pure culture while ADH1 level was similar in both pure and mixed fermentations. Conclusion In mixed fermentation, S. bombicola immobilized cells greatly affected the fermentation behavior of S. cerevisiae and the analytical composition of wine. The influence of S. bombicola on S. cerevisiae was not limited to a simple additive contribution. Indeed, its presence caused metabolic modifications during S. cerevisiae fermentation

Effect of alcoholic fermentation on the quality of grape brandies

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Vukosavljević Vera

2015-01-01

Full Text Available Grape brandy is a product obtained by fermentation and distillation of crushed grapes of cultivated grapevine Vitis vinifera. Grape brandy quality depends on many factors such as: grapevine varieties, climate, soil, time and method of distillation, storage methods and other distillates. The grapevine variety 'Neoplanta' grown in the experimental field of the PD 'Center for Viticulture and Enology' in Niš was used in the experiment. Tests were performed in the laboratory of the Centre. Healthy grapes of harvest maturity were squashed by a stalk-removing electric crusher. Fermentation was performed in plastic containers in the presence of the indigenous microflora of wine yeasts. This paper presents the influence of pH and inorganic nitrogen added to the fermentation medium on the content of volatile components and concentrations of higher alcohols.

Enzymic hydrolysis of starch in continuous alcoholic fermentation

Energy Technology Data Exchange (ETDEWEB)

Yarovenko, V.L.; Pykhova, S.V.; Ustinnikov, B.A.; Lazareva, A.N.; Makeev, D.M.

1965-01-01

Fermentations were conducted on a plant scale, using starch of various origins, e.g., potatoes, wheat, and other cereals, and as enzyme source a number of strains of Aspergillus oryzae, A. awamori, A. usamii, A. niger, A. batatae, and Bacillus mesentericus. The starches were broken down to a molecular weight between 900 and 1600; time requirements differed from those commonly known. Comparison of these enzymic actions to that of standard malt discloses that in breaking down a potato starch from a molecular weight of 268,000 to one of 1353 to 1556, the malt and A. Oryzae require 1 hour, whereas A. awamori and B. mesentericus require 18, and a different strain of A. awamori requires 24 hours.

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.

Volatile flavour profile of reduced alcohol wines fermented with the non-conventional yeast species Metschnikowia pulcherrima and Saccharomyces uvarum.

Science.gov (United States)

Varela, C; Sengler, F; Solomon, M; Curtin, C

2016-10-15

Production of quality wines with decreased alcohol concentration continues to be one of the major challenges facing wine producers. Therefore, there is considerable interest in the isolation or generation of wine yeasts less efficient at transforming grape sugars into ethanol. We recently demonstrated that Metschnikowia pulcherrima AWRI1149 and Saccharomyces uvarum AWRI2846 were both able to produce reduced alcohol wine when used in sequential inoculation with Saccharomyces cerevisiae. This effect is additive when both strains are co-inoculated in grape must. Here we describe the volatile flavour profile of Chardonnay and Shiraz wines produced with these two strains. Wines fermented with M. pulcherrima showed concentrations of ethyl acetate likely to affect negatively wine aroma. Wines fermented with S. uvarum and with a combination of M. pulcherrima and S. uvarum were characterised by increased concentrations of 2-phenyl ethanol and 2-phenylethyl acetate, both associated with positive sensory attributes. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

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.

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.).

Modeling of Clostridium tyrobutyricum for Butyric Acid Selectivity in Continuous Fermentation

OpenAIRE

Du, Jianjun; McGraw, Amy; Hestekin, Jamie

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 ...

GUT FERMENTATION SYNDROME

African Journals Online (AJOL)

boaz

individuals who became intoxicated after consuming carbohydrates, which became fermented in the gastrointestinal tract. These claims of intoxication without drinking alcohol, and the findings on endogenous alcohol fermentation are now called Gut. Fermentation Syndrome. This review will concentrate on understanding ...

Yeast Population Dynamics in Spontaneous and Inoculated Alcoholic Fermentations of Zametovka Must

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Franc Cus

2002-01-01

Full Text Available Inoculated fermentations, which are more rapid and more reliable than spontaneous fermentations, and assure predictable wine quality, are nowadays prevalent in Slovenia’s large-scale wine production. However, spontaneous fermentation strengthens local characteristics of wine and offers opportunities for technological innovation. In the 1999 vintage, spontaneous and inoculated fermentations of Zametovka (Vitis vinifera grape must were studied. Zametovka is the main red variety in production of traditional Slovene red blend wine, Cvicek. The diversity of yeast species and strains in both of the investigated fermentations was determined by molecular and traditional identification methods. The outset of alcoholic fermentation, yeast growth kinetics, and yeast population dynamics presents the main differences between the examined fermentations. Yeast population diversity was higher in the spontaneous process. Dominant yeast isolates from spontaneous fermentation were identified as Candida stellata, Hanseniaspora uvarum and Saccharomyces cerevisiae; whereas Saccharomyces bayanus, Pichia kluyveri, Pichia membranifaciens and Torulaspora delbrueckiim were found less frequently. Dominant species in the inoculated fermentation was Saccharomyces cerevisiae; other species found in smaller numbers were Candida stellata, Hanseniaspora uvarum and Debaryomyces hansenii var. hansenii. Using PFGE, we were able to distinguish among 15 different Saccharomyces cerevisiae strains and three different Saccharomyces bayanus strains isolated from spontaneous fermentation, whereas, in the case of inoculated fermentation, only two Saccharomyces cerevisiae strains were found. Their chromosomal patterns coincide with the chromosomal patterns of the starter culture strains.

Enzyme study of the separate stages in alcohol fermentation

Energy Technology Data Exchange (ETDEWEB)

Mar Monux, D

1968-01-01

The precise roles of ATP, DNA, and NADP in interaction with enzymes in certain of the 11 phases of fermentation are outlined. Individual enzymes which take part in the 11 phases are: (1) hexose transferase; (2) phosphohexoseisomerase; (3) fructosinase; (4) aldolase; (5) an SH-enzyme; (6) 3-phosphoglycero-1-phosphotransferase; (7) ghosphoglyceromutosase; (8) 2-phosphoglycerohydrolase; (9) pyruvic transferase; (10) pyruvic decarboxylase; (11) alcohol dehydrogenase.

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

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

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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.

Monitoring and Evaluation of Alcoholic Fermentation Processes Using a Chemocapacitor Sensor Array

Science.gov (United States)

Oikonomou, Petros; Raptis, Ioannis; Sanopoulou, Merope

2014-01-01

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. PMID:25184490

Sequential fermentation using non-Saccharomyces yeasts for the reduction of alcohol content in wine

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Ciani Maurizio

2014-01-01

Full Text Available Over the last few decades there has been a progressive increase in wine ethanol content due to global climate change and modified wine styles that involved viticulture and oenology practices. Among the different approaches and strategies to reduce alcohol content in wine we propose a sequential fermentation using immobilized non-Saccharomyces wine yeasts. Preliminary results showed that sequential fermentations with Hanseniaspora osmophila, Hanseniaspora uvarum, Metschnikowia pulcherrima, Starmerella bombicola and Saccharomyces cerevisiae strains showed an ethanol reduction when compared with pure S. cerevisiae fermentation trials.

Modelling of alcohol fermentation in a tubular reactor with high biomass recycle

Energy Technology Data Exchange (ETDEWEB)

Narodoslawsky, M; Mittmannsgruber, H; Nagl, W; Moser, A

1988-05-30

Fermentation in tubular recycle reactors with high biomass concentrations is a way to boost productivity in alcohol production. A computer model has been developed to investigate the potential as well as to establish the limits of this process from a chemical engineering point of view. The model takes into account the kinetics of the reaction, the nonideality of flow and the segregation in the bioreactor. In accordance with literature, it is shown that tubular reactors with biomass recycle can improve productivity of alcohol fermentation substantially. With the help of the computer based reactor model it was also possible to estimate the detrimental effects of cell damage due to pumping. These effects are shown to play a major role, if the biomass separation is performed by filtration units which need high flow rates, e.g. tangential flow filters.

Study of continuous acetone-butanol fermentation by Clostridium acetobutylicum

Energy Technology Data Exchange (ETDEWEB)

Yarovenko, V L; Nakhmanovich, B M; Shcheblykin, N P; Senkevich, V V

1960-01-01

Prophylactic sterilization of small scale equipment (2 fermenters, 3.5 cu. m. each) permitted continuous fermentation through 6 cycles (28 days), each with a new inoculum of C. acetobutylicum. Single cycles could be prolonged to 6 to 11 days without sterilization. Contamination, usually with lactic acid bacteria, sometimes preceded exhaustion of the culture. Input of flour mash at 0.6 to 1.2 cu. m./hr. and withdrawal of products were continuous; acetone yield 6.6 to 7.1 g./l.; residual sugars 0.63 to 0.79%.

Characteristics of fermentation of refined cane sugar syrup for alcohol

Energy Technology Data Exchange (ETDEWEB)

Raev, Z A; Bazilevich, K K

1956-01-01

Technological properties of cane sugar syrup, obtained on refining of raw cane sugar, were investigated. Its poor fermentation is caused by the lack of nitrous substances (1/10 as much as in sugar beet) necessary for the nutrition of yeast. It is necessary to introduce into the mixture of yeast and must 0.8% (NH/sub 4/)/sub 2/SO/sub 4/ based on weight of syrup (at a permanent aeration the assimilability of N from (NH/sub 4/)/sub 2/SO/sub 4/ by the yeast will be higher and the dosage has to be increased), 1% of superphosphate or 0.12% of a 70% phosphoric acid solution, and 0.5% of a yeast autolyst. For the fermentation of cane sugar syrup the mixture of yeast and must has to be prepared with a concentration of 10 to 11/sup 0/ by the saccharometer scale, but the average initial concentration of the fermentive must has to be 17 to 18/sup 0/ with the intention to keep the alcohol content of the ripe must at 8.7 to 8.8% by volume. Considering the low buffer ability of the syrup from cane sugar, the acidity of the must, mixed with yeast, has to be kept less than or equal to 0.4 to 0.5/sup 0/, the pH at 4.6 to 4.8; on a higher acidity the pH drops to a value which inhibits the fission of the yeast cells. On a joint fermentation of syrup from sugar cane and sugar beets 1% of superphosphate in the form of an aqueous extract and an autolyst of yeast in an amount of 0.5% of the weight of syrup was introduced into the must; the yield of alcohol from cane sugar syrup increased compared with the yield on separate processing.

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

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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

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...

Impact of pseudo-continuous fermentation on the ethanol tolerance of Scheffersomyces stipitis.

Science.gov (United States)

Liang, Meng; Kim, Min Hea; He, Qinghua Peter; Wang, Jin

2013-09-01

In this work we conducted the pseudo-continuous fermentation, i.e., continuous fermentation with cell retention, using Scheffersomyces stipitis, and studied its effect on ethanol tolerance of the strain. During the fermentation experiments, S. stipitis was adapted to a mild concentration of ethanol (20-26 g/L) for two weeks. Two substrates (glucose and xylose) were used in different fermentation experiments. After fermentation, various experiments were performed to evaluate the ethanol tolerance of adapted cells and unadapted cells. Compared to the unadapted cells, the viability of adapted cells increased by 8 folds with glucose as the carbon source and 6 folds with xylose as the carbon source following exposure to 60 g/L ethanol for 2 h. Improved ethanol tolerance of the adapted cells was also revealed in the effects of ethanol on plasma membrane permeability, extracellular alkalization and acidification. The mathematical modeling of cell leakage, extracellular alkalization and acidification revealed that cells cultured on glucose show better ethanol tolerance than cells cultured on xylose but the differences become smaller for adapted cells. The results show that pseudo-continuous fermentation can effectively improve cell's ethanol tolerance due to the environmental pressure during the fermentation process. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Effect of fermentation parameters on bio-alcohols production from glycerol using immobilized Clostridium pasteurianum: an optimization study.

Science.gov (United States)

Khanna, Swati; Goyal, Arun; Moholkar, Vijayanand S

2013-01-01

This article addresses the issue of effect of fermentation parameters for conversion of glycerol (in both pure and crude form) into three value-added products, namely, ethanol, butanol, and 1,3-propanediol (1,3-PDO), by immobilized Clostridium pasteurianum and thereby addresses the statistical optimization of this process. The analysis of effect of different process parameters such as agitation rate, fermentation temperature, medium pH, and initial glycerol concentration indicated that medium pH was the most critical factor for total alcohols production in case of pure glycerol as fermentation substrate. On the other hand, initial glycerol concentration was the most significant factor for fermentation with crude glycerol. An interesting observation was that the optimized set of fermentation parameters was found to be independent of the type of glycerol (either pure or crude) used. At optimum conditions of agitation rate (200 rpm), initial glycerol concentration (25 g/L), fermentation temperature (30°C), and medium pH (7.0), the total alcohols production was almost equal in anaerobic shake flasks and 2-L bioreactor. This essentially means that at optimum process parameters, the scale of operation does not affect the output of the process. The immobilized cells could be reused for multiple cycles for both pure and crude glycerol fermentation.

Sensory analysis of fermented alcoholic beverages from jabuticaba produced in the city of Varre-Sai, RJ

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Leticia Tinoco Gonçalves

2014-08-01

Full Text Available Jabuticaba (Myrciariasp is a fruit native to the Atlantic Forest, belonging to the Myrtaceae family, and commonly found in Brazil. It presents considerable economic potential because it can be consumed as raw fruit or processed food. In Varre-Sai, RJ, jabuticaba is strongly used in the industrialization of alcoholic beverages. The production of fermented alcoholic alternative is used to avoid waste, and make the most of the considerable nutritional value of the fruit. The content of anthocyanins in jabuticaba ranges from 310 and 315mg/100g, relatively high value compared to other fruits considered rich in antioxidants. Therefore, sensory analyses of jabuticaba alcoholic beverages produced in Varre-Sai can improve the quality of the product and potential sales. Given that the part of jabuticaba rich in phenolic compounds is the bark, the whole use of the fruit is the best alternative to take advantage of its benefits. Sensory analysis evaluated the acceptance of fermented alcoholic of Jabuticaba, in relation to its overall rating attributes, color, flavor and aroma, based on a 9-point hedonic scale, with ends named strongly disliked (1 and strongly liked (9; as well as purchase intention of tasters by a 5-point hedonic scale, with anchor points would certainly buy (5 and would not certainly buy (1. The results showed that the products had good acceptance and the fermented Sweet Tinto was rated best in all attributes, obtaining 90.18% frequency in the acceptance of hedonic scale, with respect to global acceptance. Even in the hypothetical situation of purchase, it received 74.5% of the votes in the good range of the scale. This shows that the alcoholic fermented beverages may be an alternative for the consumption of antioxidants, and that their production can improve the income of farmers as well as help avoid fruit wasting.

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

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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.

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...

Study of optimal operation for producing onion vinegar　using　two continuously stirred tank reactors

OpenAIRE

小林, 秀彰; 山口, 文; 富田, 弘毅; 管野, 亨; 小林, 正義; KOBAYASHI, Hideaki; YAMAGUCHI, Kazaru; TOMITA, Koki; KANNO, Tohru; KOBAYASHI, Masayoshi

1997-01-01

　Onion vinegar was produced using a 2-stage continuously stirred tank reactor. Regarding the alcohol fermentation and the acetic acid fermentation examined in this study, the immobilized cells on porous ceramics offered stable production of alcohol and acetic acid for long periods of 300 and 700 days, respectively. Compared with the steady-state operation method, the temperature-change forced-cyclic operation method increased ethanol yield of alcohol fermentation by a maximum of 15％. Acetic a...

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.

Alcohol production from whey

Energy Technology Data Exchange (ETDEWEB)

Reesen, L

1978-01-01

The continuous production of ethanol from whey permeate, by fermentation of its lactose with Kluyveromyces fragilis, is described. From whey containing 4.4% lactose, production costs were very competitive with those for alcohol from molasses.

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.

The influence of nitrogen and biotin interactions on the performance of Saccharomyces in alcoholic fermentations.

Science.gov (United States)

Bohlscheid, J C; Fellman, J K; Wang, X D; Ansen, D; Edwards, C G

2007-02-01

To study the impact of assimilable nitrogen, biotin and their interaction on growth, fermentation rate and volatile formation by Saccharomyces. Fermentations of synthetic grape juice media were conducted in a factorial design with yeast assimilable nitrogen (YAN) (60 or 250 mg l(-1)) and biotin (0, 1 or 10 microg l(-1)) as variables. All media contained 240 g l(-1) glucose + fructose (1 : 1) and were fermented using biotin-depleted Saccharomyces cerevisiae strains EC1118 or UCD 522. Both strains exhibited weak growth and sluggish fermentation rates without biotin. Increased nitrogen concentration resulted in higher maximum fermentation rates, while adjusting biotin from 1 to 10 microg l(-1) had no effect. Nitrogen x biotin interactions influenced fermentation time, production of higher alcohols and hydrogen sulfide (H(2)S). Maximum H(2)S production occurred in the medium containing 60 mg l(-1) YAN and 1 microg l(-1) biotin. Nitrogen x biotin interactions affect fermentation time and volatile production by Saccharomyces depending on strain. Biotin concentrations sufficient to complete fermentation may affect the organoleptic impact of wine. This study demonstrates the necessity to consider nutrient interactions when diagnosing problem fermentations.

USE OF THE MICROWAVE RADIATION FOR UPGRADING OF A BIOMASS ALCOHOLIC FERMENTATION

Directory of Open Access Journals (Sweden)

Anna Nowicka

2017-04-01

Full Text Available Perform pretreatment is crucial particularly in the case of the use of hard-degradable biomass, the biochemical susceptibility to degradation, for example, alcoholic fermentation is limited. Biomass disintegration processes lead to the destruction of compact structures and release of the organic substance to the phase dissolved in a resultant increase in the concentration of dissolved easily degradable organic substances. Effective pretreatment should meet several criteria, including ensuring the separation of lignin from cellulose, to increase the share of amorphous cellulose, provide a higher porosity substrates, eliminate waste sugars limit formation of inhibitors, minimize energy costs. The aim of this paper is to show the possibilities of using electromagnetic microwave radiation for pre-treatment plant biomass before the fermentation process of alcohol and comparison of the effectiveness of the described method with other commonly used techniques of pre-treatment. The substrate subjected to microwave treatment has a fast rate of hydrolysis and a high content of glucose in the hydrolyzate, which increases the efficiency of the production of bioethanol.

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

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.

Continuous butyric acid fermentation coupled with REED technology for enhanced productivity

DEFF Research Database (Denmark)

Baroi, George Nabin; Skiadas, Ioannis; Westermann, Peter

strains, C.tyrobutyricum seems the most promising for biological production of butyric acid as it is characterised by higher selectivity and higher tolerance to butyric acid. However, studies on fermentative butyric production from lignocellulosic biomasses are scarce in the international literature...... of continuous fermentation mode and in-situ acids removal by Reverse Enhanced Electro Dialysis (REED) resulted to enhanced sugars consumption rates when 60% PHWS was fermented. Specifically, glucose and xylose consumption rate increased by a factor of 6 and 39, respectively, while butyric acid productivity...

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.

Comparison of microbial fermentation of high- and low-forage diets in Rusitec, single-flow continuous-culture fermenters and sheep rumen.

Science.gov (United States)

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

2009-04-01

Eight Rusitec and eight single-flow continuous-culture fermenters (SFCCF) were used to compare the ruminal fermentation of two diets composed of alfalfa hay and concentrate in proportions of 80 : 20 (F80) and 20 : 80 (F20). Results were validated with those obtained previously in sheep fed the same diets. Rusitec fermenters were fed once daily and SFCCF twice, but liquid dilution rates were similar in both types of fermenters. Mean values of pH over the 12 h postfeeding were higher (P 0.05) were found in any in vitro system. A more precise control of pH in both types of fermenters and a reduction of concentrate retention time in Rusitec could probably improve the simulation of in vivo fermentation.

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...

In Vitro Sensitivity Test in Antibiotics from the Fermentation Process in a Sugar-Alcohol Plant in the State of Paraná, Brazil

OpenAIRE

Lopes, Murilo Brandão; Faculdade de Apucarana – FAP; Silva, Thaís Medeiros Boldrin; Faculdade Metropolitana de Maringá – UNIFAMMA

2011-01-01

Since the development of different types of microorganisms is common during the fermentation process in sugar-alcohol plants, due to the processing states of prime matter, microbiological control is mandatory. In vitro sensitivity test is highly important for the fermentation process at sugar-alcohol plants since the type of antibiotic with the best antibacterial activity is evaluated. The test classifies antibiotics through their effects, namely, efficient, less efficient, slightly efficient...

ATP regeneration with enzymes of the alcohol fermentation pathway and kinases of yeast and its computer simulation

Energy Technology Data Exchange (ETDEWEB)

Asada, M; Shirai, Y; Nakanishi, K; Matsuno, R; Kimura, A; Kamikubo, T

1981-08-01

Enzymes of the alcohol fermentation pathway, adenosine kinase and adenylate kinase were extracted by incubating acetone-dried yeast cells with a simple reaction medium containing glucose, and subjected to gel filtration to remove the intermediates of alcohol fermentation formed during incubation. By using the enzyme systems as catalysts and glucose as an energy source, ATP was regenerated from adenosine. A minimum concentration of fructose 1,6-bisphosphate (FBP) of 7 mM or of ATP of 10 mM was necessary to initiate the alcohol fermentation; and concentrations of nucleotides changed abruptly with reaction time. These nonlinear phenomena might be due to action of FBPase and/or ATPase as well as the complex multienzyme systems. To understand the experimentally observed phenomena, a mathematical model of the reaction system was proposed which takes into account ATP regeneration. The calculated time-dependent concentrations of glucose, FBP, adenosine and nucleotides were in agreement with experimental values qualitatively as well as quantitatively. Moreover, the nonlinear phenomena, that is, the existence of threshold concentrations of FBP and ATP below which the reaction can not proceed and the steep changes of nucleotide concentrations were also accounted for. These results indicate that the model was quite suitable for this reaction system and useful for predicting the experimental results.

Semi-Continuous Fermentation of Onion Vinegar and Its Functional Properties.

Science.gov (United States)

Lee, Sulhee; Lee, Jin-A; Park, Gwi-Gun; Jang, Jae-Kweon; Park, Young-Seo

2017-08-08

For the fermentation of vinegar using onion, acetic acid bacteria and yeast strains with high fermentation ability were screened. Among them, Saccharomyces cerevisiae 1026 was selected as a starter for ethanol production and Acetobacter orientalis MAK88 was selected as a vinegar producer. When the two-stage fermentation of onion vinegar was performed at 28 °C, the titratable acidity reached 4.80% at 24 h of fermentation. When semi-continuous fermentation proceeded to charge-discharge consisting of three cycles, the acetic acid content reached 4.35% at 48 h of fermentation. At this stage, the fermentation efficiency, acetic acid productivity, and specific product formation rate were 76.71%, 17.73 g/(L·d), and 20.58 g/(g·h), respectively. The process in this study significantly reduced the fermentation time and simplified the vinegar production process. The content of total flavonoids and total polyphenols in onion vinegar were 104.36 and 455.41 μg/mL, respectively. The antioxidant activities of onion vinegar in terms of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic) acid (ABTS⁺) radical scavenging activity, and reducing power were 75.33%, 98.88%, and 1.28, respectively. The nitrite scavenging abilities of onion vinegar were 95.38 at pH 1.2. The onion vinegar produced in this study showed higher organoleptic acceptability than commercial onion vinegar.

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)

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.

Acetone-butyl alcohol fermentation of the cornstalk hydrolyzates prepared by the method of Riga

Energy Technology Data Exchange (ETDEWEB)

Nakhmanovich, N A; Shcheblykina, N A; Kalnina, V; Pelsis, D

1960-01-01

The possibility of use of waste instead of food products in the acetone-butyl alcohol fermentation was investigated. Crushed cornstalks hydrolyzed by the method of Riga were inverted at varying conditions. The hydrolyzate containing about 50% of reducing substances (RS), based on dry weight of cornstalks, was neutralized to pH 6.3-6.5, diluted with water to the final concentration 5.0-5.1% of RS filtered, and the filtrate sterilized. The resulting liquor (I) was mixed with the wheat meal mash containing 5% of sugar (starch calculated as glucose) and fermented. The utilization of I depended upon the regime of inversion; the optimal being 20 minutes at 115/sup 0/, hydrocoefficient 1:4. In this case the use of 40% of mash sugar in form of I did not impair the yield of fermentation. The use of corn instead of wheat meal decreased the yield of butanol and increased that of ethanol. The fermentation of the mixture of I (final concentration 3% RS) and corn gluten (final concentration 2%), mineral salts added, gave higher yields than did the fermentation of the wheat meal mash.

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)

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

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.

Microbial inactivation and MLF performances of Tempranillo Rioja wines treated with PEF after alcoholic fermentation.

Science.gov (United States)

González-Arenzana, Lucía; López-Alfaro, Isabel; Garde-Cerdán, Teresa; Portu, Javier; López, Rosa; Santamaría, Pilar

2018-03-23

This study was performed with the aim of reducing the microbial communities of wines after alcoholic fermentation to improve the establishment of commercial Oenococcus oeni inoculum for developing the malolactic fermentation. Microbial community reduction was accomplished by applying Pulsed Electric Field (PEF) technology to four different wines. Overall, significant reductions in yeast population were observed. To a lesser extent, lactic acid bacteria were reduced while acetic acid bacteria were completely eliminated after the PEF treatment. In three out of the four tested wines, a decrease in the competitive pressure between microorganisms due to the detected reduction led to a general but slight shortening of the malolactic fermentation duration. In the wine with the most adverse conditions to commercial starter establishment, the shortest malolactic fermentation was reached after PEF treatment. Finally, the sensorial quality of three out of the four treated wines was considered better after the PEF treatment. Therefore, PEF technology meant an important tool for improving the malolactic fermentation performance. Copyright © 2018 Elsevier B.V. All rights reserved.

Optimisation of continuous gas fermentation by immobilisation of acetate-producing Acetobacterium woodii.

Science.gov (United States)

Steger, Franziska; Rachbauer, Lydia; Windhagauer, Matthias; Montgomery, Lucy F R; Bochmann, Günther

2017-08-01

Hydrogen from water electrolysis is often suggested as a way of storing the excess energy from wind and solar power plants. However, unlike natural gas, hydrogen is difficult to store and distribute. One solution is to convert the hydrogen into other fuels or bulk chemicals. In this study we investigated fermentation in which homoacetogenic clostridia apply the Wood-Ljungdahl pathway to generate acetate from H 2 and CO 2 . Acetate can be used as a bulk chemical or further transformed into biofuels. Autotrophic growth with CO 2 as the sole carbon source is slow compared to heterotrophic growth, so the aim of this work was to improve continuous gas fermentation by immobilising the acetate-producing clostridia, thus preventing their wash out from the bioreactor. Two homoacetogenic bacterial strains (Acetobacterium woodii and Moorella thermoacetica) were tested for their acetate production potential, with A. woodii proving to be the better strain with maximum acetate concentration of 29.57 g l -1 . Due to its stability during fermentation and good bacterial immobilisation, linen was chosen as immobilisation material for continuous fermentation. This study demonstrates the successful continuous fermentation of acetate from H 2 and CO 2 using A. woodii immobilised on a low-cost surface at high volumetric productivity of 1.21 ± 0.05 g acetate l -1 d -1 . This has great industrial potential and future studies should focus on the scale-up of this process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simulation of an alcoholic fermentation, using honey like substrate

International Nuclear Information System (INIS)

Gomez, Jose Angel; Castano, Hader Ivan; Arias Mario

1997-01-01

The article describes the implementation of a mathematical model for the simulation of an alcoholic fermentation using honey like substrate. To carry out it, the kinetic data were adjusted to equations of curves with which were calculated the derivates of the concentrations in the time, with the objective of calculating the specific speeds of growth and product formation; once fact this, it proceeded to evaluate the adjustment of the different inhibition models, so much of substrate as of product on the kinetics of the process, finding that the pattern that more it was adjusted it was the exponential, also working lineal, parabolic model, etc. with the equations for μ (specific speed of growth of biomass) and v (specific speed of product formation) it proceeded to carry out the balances of mass, with the purpose of outlining the pattern of differential equations of first order and with conditions given initials. This system was solved for numeric methods using the Euler algorithm modified for that which was required to elaborate a computer program and this way, the behavior of the feigned fermentation, for its later confrontation with the experimental data

Alcohol

Science.gov (United States)

... created when grains, fruits, or vegetables are fermented . Fermentation is a process that uses yeast or bacteria to change the sugars in the food into alcohol. Fermentation is used to produce many necessary items — everything ...

Pleiotropic functions of the yeast Greatwall-family protein kinase Rim15p: a novel target for the control of alcoholic fermentation.

Science.gov (United States)

Watanabe, Daisuke; Takagi, Hiroshi

2017-06-01

Rim15p, a Greatwall-family protein kinase in yeast Saccharomyces cerevisiae, is required for cellular nutrient responses, such as the entry into quiescence and the induction of meiosis and sporulation. In higher eukaryotes, the orthologous gene products are commonly involved in the cell cycle G 2 /M transition. How are these pleiotropic functions generated from a single family of protein kinases? Recent advances in both research fields have identified the conserved Greatwall-mediated signaling pathway and a variety of downstream target molecules. In addition, our studies of S. cerevisiae sake yeast strains revealed that Rim15p also plays a significant role in the control of alcoholic fermentation. Despite an extensive history of research on glycolysis and alcoholic fermentation, there has been no critical clue to artificial modification of fermentation performance of yeast cells. Our finding of an in vivo metabolic regulatory mechanism is expected to provide a major breakthrough in yeast breeding technologies for fermentation applications.

Effects of concentrate replacement by feed blocks on ruminal fermentation and microbial growth in goats and single-flow continuous-culture fermenters.

Science.gov (United States)

Molina-Alcaide, E; Pascual, M R; Cantalapiedra-Hijar, G; Morales-García, E Y; Martín-García, A I

2009-04-01

The effect of replacing concentrate with 2 different feed blocks (FB) on ruminal fermentation and microbial growth was evaluated in goats and in single-flow continuous-culture fermenters. Diets consisted of alfalfa hay plus concentrate and alfalfa hay plus concentrate with 1 of the 2 studied FB. Three trials were carried out with 6 rumen-fistulated Granadina goats and 3 incubation runs in 6 single-flow continuous-culture fermenters. Experimental treatments were assigned randomly within each run, with 2 repetitions for each diet. At the end of each in vivo trial, the rumen contents were obtained for inoculating the fermenters. For each incubation run, the fermenters were inoculated with ruminal fluid from goats fed the same diet supplied to the corresponding fermenter flask. The average pH values, total and individual VFA, and NH(3)-N concentrations, and acetate:propionate ratios in the rumen of goats were not affected (P >or= 0.10) by diet, whereas the microbial N flow (MNF) and efficiency were affected (P fermenters, the diet affected pH (Por= 0.05), and total (P=0.02), NH(3) (P=0.005), and non-NH(3) (P=0.02) N flows, whereas the efficiency of VFA production was not affected (P=0.75). The effect of diet on MNF and efficiency depended on the bacterial pellet used as a reference. An effect (Pfermenter contents and effluent were similar (P=0.05). Differences (Pfermentation variables and bacterial pellet compositions were found. Partial replacement of the concentrate with FB did not greatly compromise carbohydrate fermentation in unproductive goats. However, this was not the case for MNF and efficiency. Differences between the results obtained in vivo and in vitro indicate a need to identify conditions in fermenters that allow better simulation of fermentation, microbial growth, and bacterial pellet composition in vivo. Reduced feeding cost could be achieved with the inclusion of FB in the diets of unproductive goats without altering rumen fermentation.

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

Alcohol from whey

Energy Technology Data Exchange (ETDEWEB)

1982-03-01

A process for ethanol production from whey is described. The lactose is fermented into alcohol via glucose and galactose of yeast. The whey must be pasteurized before fermentation in order to reduce the concentration of microorganisms in the protein fraction. The protein is separated by ultrafiltration. The whey, which is now rather free of bacteria, is introduced into the fermentation unit where yeast cultures are added to it. After fermentation, the yeast slurry is separated and processed into feeding yeast while the mash is passed on to the distillation unit. The alcohol thus produced is of very high quality and may be added to alcoholic beverages.

[Continuous ethanol fermentation coupled with recycling of yeast flocs].

Science.gov (United States)

Wang, Bo; Ge, Xu-Meng; Li, Ning; Bai, Feng-Wu

2006-09-01

A continuous ethanol fermentation system composed of three-stage tanks in series coupled with two sedimentation tanks was established. A self-flocculating yeast strain developed by protoplast fusion from Saccharomyces cerevisiae and Schizosaccharomyces pombe was applied. Two-stage enzymatic hydrolysate of corn powder containing 220g/L of reducing sugar, supplemented with 1.5g/L (NH4)2HPO4 and 2.5g/L KH2PO4, was used as the ethanol fermentation substrate and fed into the first fermentor at the dilution rate of 0.057h(-1). The yeast flocs separated by sedimentation were recycled into the first fermentor as two different models: activation-recycle and direct recycle. The quasi-steady states were obtained for both operation models after the fermentation systems experienced short periods of transitions. Activation process helped enhance the performance of ethanol fermentation at the high dilution rates. The broth containing more than 101g/L ethanol, 3.2g/L residual reducing sugar and 7.7g/L residual total sugar was produced. The ethanol productivity was calculated to be 5.77g/(L x h), which increased by more than 70% compared with that achieved in the same tank in series system without recycling of yeast cells.

Optimization of alcohol production from Jerusalem artichokes

Energy Technology Data Exchange (ETDEWEB)

Guiraud, J.P.; Caillaud, J.M.; Galzy, P.

1982-01-01

Fermentation of Jerusalem artichoke extracts by yeasts with inulinase activity is possible, without prior hydrolysis or sterilization, if carried out at pH 3.5. For semi-continuous production, a small amount of the yeast harvested at the end of the previous fermentation can be used as the subsequent inoculant. Up to 75 hl of alcohol per ha can be obtained by this process under favorable energetic conditions. A partial inhibition of the fermentation was detected in extracts obtained from tubers harvested too early; this inhibition seems unrelated to the extent of polymerization of sugars.

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.)

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

Alcoholic fermentation of stored sweet potatoes

Energy Technology Data Exchange (ETDEWEB)

Yutaka, Y; One, H

1958-01-01

Sweet potatoes were ground and stored in a ground hold. The stored sweet potatoes gave about 90% fermentation efficiency by the koji process. A lower fermentation efficiency by the amylo process was improved by adding 20 to 30 mg/100 ml of organic N. Inorganic N has no effect in improving the fermentation efficiency of the stored sweet potatoes by the amylo process.

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.

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.

Basis for the optimum process parameters in the fermentation of hydrolyzates and spent sulfite liquors

Energy Technology Data Exchange (ETDEWEB)

Raitseva, M K

1964-01-01

Data are presented on technical processes used in hydrolysis plants, and on the carbohydrate compound of the most typical samples of softwood hydrolyzates. The operation of the fermentation equipment and the product quality depend on the dilution factor. Data are also given on the continuous fermentation of sugar into alcohol and on its dependence on the dilution factor.

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

Effect of juice and fermented vinegar from Hovenia dulcis peduncles on chronically alcohol-induced liver damage in mice.

Science.gov (United States)

Xiang, Jinle; Zhu, Wenxue; Li, Zhixi; Ling, Shengbao

2012-06-01

The protective effects of juice and fermented vinegar from Hovenia dulcis peduncles on chronically ethanol-induced biochemical changes in male mice were investigated. Administration of ethanol (50%, v/v, 10 mL kg⁻¹) to mice for 6 weeks induced liver damage with a significant increase (P vinegar from Hovenia dulcis peduncles (10 mL kg⁻¹ bw) along with alcohol significantly (P vinegar from Hovenia dulcis peduncles showed better profiles of the antioxidant systems with relatively higher glutathione (GSH) content, total superoxide dismutase (T-SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities. All these results were accompanied by histological observations in liver. The results demonstrate that both of the juice and fermented vinegar from Hovenia dulcis peduncles have beneficial effects in reducing the adverse effect of alcohol.

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.

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.

Gas chromatographic quantitative analysis of the gaseous emissions and carbon balance in the alcoholic fermentation

Directory of Open Access Journals (Sweden)

C. Chon

1997-06-01

ln order to try to answer to this question, methods able to analyse simultaneously and quantitatively the liquid phase, the gaseous emissions and the biomass are needed. Recently, we have shown that under suitable defined conditions 13C NMR spectroscopy allows the quantitative measurement of at least eight components present at a concentration up to 5 x 10-3M (glycerol, glucose, butandiols, tartric, malic, lactic, citric and succinic acids in a short time (one hour with a precision of about 3 p. cent. The measurements of the ethanol concentrations and of the amount of carbon transferred in the biomass are easily achieved using respectively ebullioscopic and standard combustion techniques. We are now able to extend these results and to show that, by using gas chromatography in a continuous dynamic mode and under a sweep of air at the head space of the fermentor, it is possible to measure quantitatively the mixture of volatile substances (composed mainly of air, carbon dioxide, ethanol and water emanating from an alcoholic fermentation. The results obtained, when correlated with quantitative 13C NMR spectroscopy on the medium components permits the total balance sheet of the carbon transfers occuring during the fermentation process betwcen the liquid and the gaseous phases to be established. Our results indicate that the losses of ethanol during the fermentation process conducted under an air flow at the head space of the fermentor, may reach about 10 p. cent of the theoretical maximal amount of ethanol produced. The experiments presented here could explain the ethanol losses observed during some vinification processes conducted in open tanks.

Conversion of yellow crude sugar into alcohol. Conversion of yellow crude sugar in a mixture with sugar beet molasses

Energy Technology Data Exchange (ETDEWEB)

Krishtul, F B; Malchenko, A L; Poluyanova, M T; Gromovich, V F; Maskimova, E A; Golodovskaya, A I; Pal' gova, L S

1963-01-01

Crude sugar (96.5 to 98.4% sucrose) in a mixture with molasses can be converted into alcohol by either batchwise or continuous fermentation processes with good process characteristics. Best yields are obtained when the amount of crude sugar is not more than 50% of the total weight of fermenting material. The bakers' yeast and alcohol produced are of good quality.

Optimization of alcohol production from Jerusalem artichokes

Energy Technology Data Exchange (ETDEWEB)

Guiraud, J.P.; Caillaud, J.M.; Galzy, P.

1982-01-01

Fermentation of Jerusalem artichoke extracts by yeasts with inulinase activity is possible, without prior hydrolysis or sterilization, if carried out at pH 3.5. For semi-continuous production, a small amount of the yeast harvested at the end of the previous fermentation can be used as the subsequent inoculant. Up to 75 hl of alcohol per ha can be obtained by this process under favorable energetic conditions. A partial inhibition of the fermentation was detected in extracts obtained from tubers harvested too early; this inhibition seems unrelated to the extent of polymerization of sugars. (Refs. 9).

Alcoholic fermentation of sorghum and other grains by using a fungal amylase

Energy Technology Data Exchange (ETDEWEB)

Blaisten, R J

1961-01-01

Destilasa is the trade ame of a fungal ..gamma..-amylase obtained from a strain of Aspergillus awamori for use in grain distilleries in Argentina. Using sorghum mash, 57% starch, 2 to 5% Destilasa gave fermentation efficiencies from 76 to 94%, malt 78%, acid conversion 75%. Other starchy materials tested were rye, potatoes, and sweet potatoes. Cooking and saccharification procedures were given in detail for corn, sorghum, and rye. An industrial procedure was outlined in detail and might be applicable to alcohol distilleries using sugar cane.

A set of nutrient limitations trigger yeast cell death in a nitrogen-dependent manner during wine alcoholic fermentation.

Directory of Open Access Journals (Sweden)

Camille Duc

Full Text Available Yeast cell death can occur during wine alcoholic fermentation. It is generally considered to result from ethanol stress that impacts membrane integrity. This cell death mainly occurs when grape musts processing reduces lipid availability, resulting in weaker membrane resistance to ethanol. However the mechanisms underlying cell death in these conditions remain unclear. We examined cell death occurrence considering yeast cells ability to elicit an appropriate response to a given nutrient limitation and thus survive starvation. We show here that a set of micronutrients (oleic acid, ergosterol, pantothenic acid and nicotinic acid in low, growth-restricting concentrations trigger cell death in alcoholic fermentation when nitrogen level is high. We provide evidence that nitrogen signaling is involved in cell death and that either SCH9 deletion or Tor inhibition prevent cell death in several types of micronutrient limitation. Under such limitations, yeast cells fail to acquire any stress resistance and are unable to store glycogen. Unexpectedly, transcriptome analyses did not reveal any major changes in stress genes expression, suggesting that post-transcriptional events critical for stress response were not triggered by micronutrient starvation. Our data point to the fact that yeast cell death results from yeast inability to trigger an appropriate stress response under some conditions of nutrient limitations most likely not encountered by yeast in the wild. Our conclusions provide a novel frame for considering both cell death and the management of nutrients during alcoholic fermentation.

Dynamics in population heterogeneity during batch and continuous fermentation of Saccharomyces cerevisiae

DEFF Research Database (Denmark)

Heins, Anna-Lena; Lencastre Fernandes, Rita; Lundin, L.

2012-01-01

Traditionally, microbial populations in optimization studies of fermentation processes have been considered homogeneous. However, research has shown that a typical microbial population in fermentation is heterogeneous. There are indications that this heterogeneity may be both beneficial...... (facilitates quick adaptation to new conditions) and harmful (reduces yields and productivities)[1,2]. Typically, gradients of e.g. dissolved oxygen, substrates, and pH are observed in industrial scale fermentation processes. Consequently, microbial cells circulating throughout a bioreactor experience rapid...... distribution during different growth stages. To further simulate which effect gradients have on population heterogeneity, glucose and ethanol perturbations during continuous cultivation were performed. Physiological changes were analyzed on single cell level by using flow cytometry followed by cell sorting...

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 manner...

OXYGEN MANAGEMENT DURING ALCOHOLIC FERMENTATION

OpenAIRE

MOENNE VARGAS, MARÍA ISABE

2013-01-01

Oxygen additions are a common practice in winemaking, as oxygen has a positive effect in fermentative kinetics, biomass synthesis and improvement of color, structure and :flavor in treated wines. However, most oxygen additions are carried out heuristically through pump-over operations solely on a know-how basis, which is difficult to manage in terms of the exact quantity of oxygen transferred to the fermenting must. It is important to estímate the amount of oxygen added because...

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.

Continuous dry fermentation of swine manure for biogas production

International Nuclear Information System (INIS)

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

2015-01-01

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) −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·(L d) −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

Improving the quality of matured coconut (Cocos nucifera Linn.) water by low alcoholic fermentation with Saccharomyces cerevisiae: antioxidant and volatile profiles.

Science.gov (United States)

Zhang, Guanfei; Chen, Wenxue; Chen, Weijun; Chen, Haiming

2018-03-01

Matured coconut water (MCW) is a by-product in the coconut milk industry that is usually discarded due to its unpleasant flavor. In this study, low-alcohol coconut water (LACW) was fermented with Saccharomyces cerevisiae to improve the quality of MCW. Volatile components and nonvolatile flavor-related elements were estimated to compare the qualities of the MCW and LACW. Besides measuring the kinetic changes, the levels of fructose, glucose, sucrose and ethanol contents were also determined. The results of the organic acid assays showed that tartaric, pyruvic and succinic acids were the primary organic acids present in LACW and increased significantly with fermentation. The resulting volatile composition assay indicated that esters, alcohols and fatty acids were significantly influenced by fermentation and yeast strains. Moreover, 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), cupric ion reducing antioxidant capacity and ferric reducing antioxidant power values increased significantly throughout the process, correlating with the enhancement of total phenolic content.

Reduced Production of Higher Alcohols by Saccharomyces cerevisiae in Red Wine Fermentation by Simultaneously Overexpressing BAT1 and Deleting BAT2.

Science.gov (United States)

Ma, Lijuan; Huang, Shiyong; Du, Liping; Tang, Ping; Xiao, Dongguang

2017-08-16

In red wine, the contents of higher alcohols and ethyl carbamate (EC) are two significant health concerns. To reduce the production of higher alcohols by wine yeast YZ22 with low production of EC, one BAT2 was replaced by a BAT1 expression cassette first and then another BAT2 was deleted to obtain the mutant SYBB3. Real-time quantitative PCR showed that the relative expression level of BAT1 in SYBB3 improved 28 times compared with that in YZ22. The yields of isobutanol and 3-methyl-1-butanol produced by mutant SYBB3 reduced by 39.41% and 37.18% compared to those by the original strain YZ22, and the total production of higher alcohols decreased from 463.82 mg/L to 292.83 mg/L in must fermentation of Cabernet Sauvignon. Meanwhile, there were no obvious differences on fermentation characteristics of the mutant and parental strain. This research has suggested an effective strategy for decreasing production of higher alcohols in Saccharomyces cerevisiae.

Analysis of continuous fermentation processes in aqueous two-phase systems

Energy Technology Data Exchange (ETDEWEB)

Jarzebski, A B; Malinowski, J J [Polish Academy of Sciences, Gliwice (Poland). Inst. of Chemical Engineering; Goma, G; Soucaille, P [INSA, 31 - Toulouse (France). Dept. de Genie Biochimique et Alimentaire

1992-05-01

Simulations of continuous ethanol or acetonobutylic fermentations in aqueous two-phase systems show that at high substrate feed concentrations it is possible to obtain solvent productivities about 25-40% higher than in conventional systems with cell recycle if the biomass bleed rate is kept about one tenth of the value of D. (orig.).

Exploration of Yeast and Bacteria Contaminants in Seed Culture and Fermented Wort from Gyo Gon Alcohol Distillery

International Nuclear Information System (INIS)

Ngwe Thein

2005-10-01

Study was made on samples of seed culture and fermented wort from Gyogon alcohol distillery. In all samples bacteria contaminants were observed. Samples were cultured on Sabouraud dextrose agar, Czapek Dox agar, and nutrient agar media and broth. The selected colonies were isolated. Biochemical tests for identification were conducted. The yeast and bacteria contaminants were identified by morphological characteristics and biochemical reactions. The yeast isolated and identified from Gyogon alcohol distillery was Sacchacromyces cerevisiae. The bacteria contaminants isolated and identified were Aeromonas sp. and Pseudomonas sp.

Gradient simulation experiments for targeting population heterogeneity in continuous Saccharomyces cerevisiae fermentation

DEFF Research Database (Denmark)

Heins, Anna-Lena; Lencastre Fernandes, Rita; Lundin, L.

Traditionally, a microbial population has been considered homogeneous in optimization studies of fermentation processes. However, research has shown that a typical microbial population in a fermenter is heterogeneous. There are indications that such heterogeneity may be both beneficial (facilitates...... quick adaptation to new conditions) and harmful (reduces yields and productivities) (Bylund et al. (1998); Enfors et al. (2001)). Significant gradients of e.g. dissolved oxygen, substrates, and pH are typically observed in many industrial scale fermentation processes. Consequently, the microbial cells...... reporter strain demonstrated a highly dynamic behaviour with regards to subpopulation distribution during the different growth stages. To simulate which effect glucose gradients, often seen in large scale cultivations, have on population heterogeneity, glucose perturbations during continuous cultivation...

Silage alcohols in dairy cow nutrition

DEFF Research Database (Denmark)

Raun, Birgitte Marie Løvendahl

Corn silages with high propanol concentrations has been suspected to cause reduced feed intake and health problems for dairy cows in the post-pattum transition period. With the increasing use of hetero fermentative inoculants to support corn silage fermentation it is likely that silage concentrat......Corn silages with high propanol concentrations has been suspected to cause reduced feed intake and health problems for dairy cows in the post-pattum transition period. With the increasing use of hetero fermentative inoculants to support corn silage fermentation it is likely that silage...... of alcohols will lead to high alcohol concentrations in peripheral bood for a considerable period. Increased hepatic NEFA uptake in the postpartum transition period may result in even further decreased hepatic capacity for alcohol metabolism making post-partum transition cows especially vulnerable to high...... alcohol intakes. In order to evaluate the impact of alcohol fermentation in corn silages on dairy cow performance, the main purpose of this thesis was first to investigate the concentrations and composition of alcohols in typical field corn silages, and second to study how transition and lactating dairy...

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 0.44g ethanol g sugarconsumed -1 and an ethanol specific production rate of 5.96g ethanol (Lh) -1 . As the assayed soft drinks wastewaters contain about 105g sugar /L of fermentable sugars, the concentration of ethanol achieved after the fermentations process was 46.2g ethanol /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.

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.

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.)

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.

A novel approach of modeling continuous dark hydrogen fermentation.

Science.gov (United States)

Alexandropoulou, Maria; Antonopoulou, Georgia; Lyberatos, Gerasimos

2018-02-01

In this study a novel modeling approach for describing fermentative hydrogen production in a continuous stirred tank reactor (CSTR) was developed, using the Aquasim modeling platform. This model accounts for the key metabolic reactions taking place in a fermentative hydrogen producing reactor, using fixed stoichiometry but different reaction rates. Biomass yields are determined based on bioenergetics. The model is capable of describing very well the variation in the distribution of metabolic products for a wide range of hydraulic retention times (HRT). The modeling approach is demonstrated using the experimental data obtained from a CSTR, fed with food industry waste (FIW), operating at different HRTs. The kinetic parameters were estimated through fitting to the experimental results. Hydrogen and total biogas production rates were predicted very well by the model, validating the basic assumptions regarding the implicated stoichiometric biochemical reactions and their kinetic rates. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

OpenAIRE

Martínez-Gil, A. M.; Garde-Cerdán, Teresa; Lorenzo, Cándida; Félix Lara, J.; Pardo, F.; Rosario Salinas, M.

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...

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.

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.

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.

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. (c) 2010. Published by Elsevier Ltd. All rights reserved.

TRADITIONAL FERMENTED FOODS OF LESOTHO

Directory of Open Access Journals (Sweden)

Tendekayi H. Gadaga

2013-06-01

Full Text Available This paper describes the traditional methods of preparing fermented foods and beverages of Lesotho. Information on the preparation methods was obtained through a combination of literature review and face to face interviews with respondents from Roma in Lesotho. An unstructured questionnaire was used to capture information on the processes, raw materials and utensils used. Four products; motoho (a fermented porridge, Sesotho (a sorghum based alcoholic beverage, hopose (sorghum fermented beer with added hops and mafi (spontaneously fermented milk, were found to be the main fermented foods prepared and consumed at household level in Lesotho. Motoho is a thin gruel, popular as refreshing beverage as well as a weaning food. Sesotho is sorghum based alcoholic beverage prepared for household consumption as well as for sale. It is consumed in the actively fermenting state. Mafi is the name given to spontaneously fermented milk with a thick consistency. Little research has been done on the technological aspects, including the microbiological and biochemical characteristics of fermented foods in Lesotho. Some of the traditional aspects of the preparation methods, such as use of earthenware pots, are being replaced, and modern equipment including plastic utensils are being used. There is need for further systematic studies on the microbiological and biochemical characteristics of these these products.

Aminobutyric acid and formation of higher alcohols by Saccharomyces carlsbergenesis

Energy Technology Data Exchange (ETDEWEB)

Babaeva, S A; Veselov, I Ya; Gracheva, I M

1966-01-01

Aminobutyric acid (1) added before the start of fermentation increased the formation of propyl-, isobutyl-, and isoamyl alcohols. With addition of I after 24, 28, or 72 hours of fermentation, the formation of the alcohols gradually decreased. Addition of I after 3 days of fermentation did not affect formation of the higher alcohols. I was not the source of formation of the higher alcohols, but affected the metabolism of carbohydrates and N in the cells. Formation of hexyl alcohols and high amounts of aldehydes was observed only during aerobic fermentation.

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.

Continuous energy recovery and nutrients removal from molasses wastewater by synergistic system of dark fermentation and algal culture under various fermentation types.

Science.gov (United States)

Ren, Hong-Yu; Kong, Fanying; Ma, Jun; Zhao, Lei; Xie, Guo-Jun; Xing, Defeng; Guo, Wan-Qian; Liu, Bing-Feng; Ren, Nan-Qi

2018-03-01

Synergistic system of dark fermentation and algal culture was initially operated at batch mode to investigate the energy production and nutrients removal from molasses wastewater in butyrate-type, ethanol-type and propionate-type fermentations. Butyrate-type fermentation was the most appropriate fermentation type for the synergistic system and exhibited the accumulative hydrogen volume of 658.3 mL L -1 and hydrogen yield of 131.7 mL g -1 COD. By-products from dark fermentation (mainly acetate and butyrate) were further used to cultivate oleaginous microalgae. The maximum algal biomass and lipid content reached 1.01 g L -1 and 38.5%, respectively. In continuous operation, the synergistic system was stable and efficient, and energy production increased from 8.77 kJ L -1  d -1 (dark fermentation) to 17.3 kJ L -1  d -1 (synergistic system). Total COD, TN and TP removal efficiencies in the synergistic system reached 91.1%, 89.1% and 85.7%, respectively. This study shows the potential of the synergistic system in energy recovery and wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nonlinear analysis and control of a continuous fermentation process

DEFF Research Database (Denmark)

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

2002-01-01

Different types of nonlinear controllers are designed and compared for a simple continuous bioreactor operating near optimal productivity. This operating point is located close to a fold bifurcation point. Nonlinear analysis of stability, controllability and zero dynamics is used to investigate o...... 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....

Alcoholic fermentation of starchy and sugary materials

Energy Technology Data Exchange (ETDEWEB)

Gulyaev, S P

1958-06-25

To promote complete fermentation of the sugar and to reduce the formation of glycerol and other by-products, the ester-aldehyde fraction is introduced to the fermentation mixture at the beginning of the process.

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.

Fermentation of galactose when preparing alcohol from the molasses from sugar beets

Energy Technology Data Exchange (ETDEWEB)

Rosa, M

1959-01-01

A number of yeast strains (referred to by Soviet code-name only), which ferment sucrose, glucose, fructose, raffinose, and (or) melibose in beet molasses, will also ferment the galactose contained therein if they are raised first on a medium containing galactose, KH/sub 2/PO/sub 4/, (NH/sub 4/)/sub 2/SO/sub 3/, and MgSO/sub 4/ at pH 5.5. This was experimentally proved by aid of 2-dimensional paper chromatography; the chromatograms were developed at 18/sup 0/ from samples which were removed once every 24 hours from the fermentation liquor. Depending upon the strains used the galactose would disappear from the mash in 3 to 5 days. These experiments could never be continued longer than 5 days, as by that time the ethanol content of the mash was too high to allow any further assimilation of the galactose by the yeasts.

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. Copyright © 2012 Elsevier Ltd. All rights reserved.

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)

The impact of oxygen on the final alcohol content of wine fermented by a mixed starter culture.

Science.gov (United States)

Morales, Pilar; Rojas, Virginia; Quirós, Manuel; Gonzalez, Ramon

2015-05-01

We have developed a wine fermentation procedure that takes advantage of the metabolic features of a previously characterized Metschnikowia pulcherrima strain in order to reduce ethanol production. It involves the use of M. pulcherrima/Saccharomyces cerevisiae mixed cultures, controlled oxygenation conditions during the first 48 h of fermentation, and anaerobic conditions thereafter. The influence of different oxygenation regimes and initial inoculum composition on yeast physiology and final ethanol content was studied. The impact of oxygenation on yeast physiology goes beyond the first aerated step and influences yields and survival rates during the anaerobic stage. The activity of M. pulcherrima in mixed oxygenated cultures resulted in a clear reduction in ethanol yield, as compared to S. cerevisiae. Despite relatively low initial cell numbers, S. cerevisiae always predominated in mixed cultures by the end of the fermentation process. Strain replacement was faster under low oxygenation levels. M. pulcherrima confers an additional advantage in terms of dissolved oxygen, which drops to zero after a few hours of culture, even under highly aerated conditions, and this holds true for mixed cultures. Alcohol reduction values about 3.7 % (v/v) were obtained for mixed cultures under high aeration, but they were associated to unacceptable volatile acidity levels. In contrast, under optimized conditions, only 0.35 g/L acetic acid was produced, for an alcohol reduction of 2.2 % (v/v), and almost null dissolved oxygen during the process.

Ethyl alcohol by fermentation

Energy Technology Data Exchange (ETDEWEB)

1952-02-13

Ethanol is made from solutions poor in sugar and free of yeast carriers, e.g. from whey, by fermentation under sterile conditions. The CO/sub 2/ formed in the decomposition of sugar is used as an agitating medium to ensure good contact between the yeast and the sugar.

Steady-state and transient-state analyses of aerobic fermentation in Saccharomyces kluyveri

DEFF Research Database (Denmark)

Møller, Kasper; Bro, Christoffer; Piskur, Jure

2002-01-01

Some yeasts, such as Saccharomyces cerevisiae, produce ethanol at fully aerobic conditions, whereas other yeasts, such as Kluyveromyces lactis, do not. In this study we investigated the occurrence of aerobic alcoholic fermentation in the petite-negative yeast Saccharomyces kluyveri that is only...... distantly related to S. cerevisiae. In aerobic glucose-limited continuous cultures of S. kluyveri, two growth regimens were observed: at dilution rates below 0.5 h(-1) the metabolism was purely respiratory, and at dilution rates above 0.5 h-1 the metabolism was respiro-fermentative. The dilution rate...... a delay of 20-50 min (depending on culture conditions prior to the pulse), which is in contrast to S. cerevisiae that ferments immediately after glucose addition....

Method for saccharification and fermentation of mashes containing polysaccharides for alcohol

Energy Technology Data Exchange (ETDEWEB)

Beubler, A.; Giang, B.; Dempwolf, M.; Dickscheit, R.; Lietz, P.; Nielebock, C.; Peglow, K.; Sattelberg, K.

1970-01-01

Twenty-five g comminuted grain are steeped in 200 ml water. At 5/sup 0/C, 0.02% (in terms of grain mass) ..cap alpha..-amylase preparation is added at 5/sup 0/C, and the mash then treated by conventional methods so that the starch, cellulose, hemicellulose and other polysaccharides are ready for enzymatic digestion. The mash is then brought to 65/sup 0/C and saccharified with 1% ..cap alpha..-amylase and 0.2% amyloglucosidase for 45 minutes. The saccharified mash is freed from its solids, fermentation is induced after sterilization by addition of yeast, and fermentation is completed in < 36 hours by discontinuous, continuous or agitated methods. A part of the enzyme preparation can be replaced by malt.

Flocculent killer yeast for ethanol fermentation of beet molasses

Energy Technology Data Exchange (ETDEWEB)

Moriya, Kazuhito; Shimoii, Hitoshi; Sato, Shun' ichi; Saito, Kazuo; Tadenuma, Makoto

1987-09-25

When ethanol is produced using beet molasses, the concentration of ethanol is lower than that obtained using suger cane molasses. Yeast strain improvement was conducted to enhance ethanol production from beet molasses. The procedures and the results are as follows: (1) After giving ethanol tolerance to the flocculent yeast, strain 180 and the killer yeast, strain 909-1, strain 180-A-7, and strain 909-1-A-4 were isolated. These ethanol tolerant strains had better alcoholic fermentation capability and had more surviving cells in mash in the later process of fermentation than the parental strains. (2) Strain H-1 was bred by spore to cell mating between these two ethanol tolerant strains. Strain H-1 is both flocculent and killer and has better alcoholic fermentation capability than the parental strains. (3) In the fermentation test of beet molasses, strain H-1 showed 12.8% of alcoholic fermentation capability. It is equal to that of sugar cane molasses. Fermentation with reused cells were also successful. (5 figs, 21 refs)

Use of Gelidium amansii as a promising resource for bioethanol: a practical approach for continuous dilute-acid hydrolysis and fermentation.

Science.gov (United States)

Park, Jeong-Hoon; Hong, Ji-Yeon; Jang, Hyun Chul; Oh, Seung Geun; Kim, Sang-Hyoun; Yoon, Jeong-Jun; Kim, Yong Jin

2012-03-01

A facile continuous method for dilute-acid hydrolysis of the representative red seaweed species, Gelidium amansii was developed and its hydrolysate was subsequently evaluated for fermentability. In the hydrolysis step, the hydrolysates obtained from a batch reactor and a continuous reactor were systematically compared based on fermentable sugar yield and inhibitor formation. There are many advantages to the continuous hydrolysis process. For example, the low melting point of the agar component in G. amansii facilitates improved raw material fluidity in the continuous reactor. In addition, the hydrolysate obtained from the continuous process delivered a high sugar and low inhibitor concentration, thereby leading to both high yield and high final ethanol titer in the fermentation process. Copyright © 2011 Elsevier Ltd. All rights reserved.

Bifurcation analysis of a product inhibition model of a continuous fermentation process

Energy Technology Data Exchange (ETDEWEB)

Lenbury, Y; Chiaranai, C

1987-03-01

A product inhibition model of a continuous fermentation process is considered. If the yield term is a variable function of ethanol concentration, oscillation in the cell and ethanol concentrations is shown to be a Hopf bifurcation in the underlying system of nonlinear, ordinary differential equations which comprises the model.

27 CFR 24.212 - High fermentation wine.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false High fermentation wine. 24..., DEPARTMENT OF THE TREASURY LIQUORS WINE Production of Other Than Standard Wine § 24.212 High fermentation wine. High fermentation wine is wine made with the addition of sugar within the limitations prescribed...

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)

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)

The Fermentative and Aromatic Ability of Kloeckera and Hanseniaspora Yeasts

Science.gov (United States)

Díaz-Montaño, Dulce M.; de Jesús Ramírez Córdova, J.

Spontaneous alcoholic fermentation from grape, agave and others musts into an alcoholic beverage is usually characterized by the presence of several non-Saccharomyces yeasts. These genera yeasts are dominant in the early stages of the alcoholic fermentation. However the genera Hanseniaspora and Kloeckera may survive at a significant level during fermentation and can influence the chemical composition of the beverage. Several strains belonging to the species Kloeckera api-culata and Hanseniaspora guilliermondii have been extensively studied in relation to the formation of some metabolic compounds affecting the bouquet of the final product. Indeed some apiculate yeast showed positive oenological properties and their use in the alcoholic fermentations has been suggested to enhance the aroma and flavor profiles. The non- Saccharomyces yeasts have the capability to produce and secrete enzymes in the medium, such as β -glucosidases, which release monoterpenes derived from their glycosylated form. These compounds contribute to the higher fruit-like characteristic of final product. This chapter reviews metabolic activity of Kloeckera and Hanseniaspora yeasts in several aspects: fermentative capability, aromatic compounds production and transformation of aromatic precursor present in the must, also covers the molecular methods for identifying of the yeast

27 CFR 24.176 - Crushing and fermentation.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Crushing and fermentation..., DEPARTMENT OF THE TREASURY LIQUORS WINE Production of Wine § 24.176 Crushing and fermentation. (a) Natural... fermentation but the density of the juice may not be reduced below 22 degrees Brix. However, if the juice is...

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

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

Influence of pre-fermentation cold maceration treatment on aroma compounds of Cabernet Sauvignon wines fermented in different industrial scale fermenters.

Science.gov (United States)

Cai, Jian; Zhu, Bao-Qing; Wang, Yun-He; Lu, Lin; Lan, Yi-Bin; Reeves, Malcolm J; Duan, Chang-Qing

2014-07-01

The influence of pre-fermentation cold maceration (CM) on Cabernet Sauvignon wines fermented in two different industrial-scale fermenters was studied. CM treatment had different effects on wine aroma depending on the types of fermenter, being more effective for automatic pumping-over tank (PO-tank) than automatic punching-down tank (PD-tank). When PO-tank was used, CM-treated wine showed a decrease in some fusel alcohols (isobutanol and isopentanol) and an increase in some esters (especially acetate esters). However, no significant changes were detected in these compounds when PD-tank was used. Ethyl 2-hexenoate and diethyl succinate were decreased, while geranylacetone was increased by the CM treatment in both fermenters. β-Damascenone was increased by the CM treatment in PO-tank fermented wines but decreased in PD-tank fermented wines. The fruity, caramel and floral aroma series were enhanced while chemical series were decreased by the CM treatment in PO-tank fermented wines. The content of (Z)-6-nonen-1-ol in the final wines was positively correlated to CM treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fermentation value of molasses for the alcohol industry

Energy Technology Data Exchange (ETDEWEB)

Sobkiewicz, G

1963-01-01

Molasses of pH 7 to 8 containing invert sugar in quantity not exceeding 1% showed the highest fermentation value. The purity coefficient should not exceed 56%, since non-sugars, minerals, and nitrogen compounds stimulated fermentation.

Hybrid Modeling and Optimization of Yogurt Starter Culture Continuous Fermentation

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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.

Influence of aeration in the fermentative activity of Kloeckera apiculata during fermentation of apple juice

International Nuclear Information System (INIS)

Estela Escalante, Waldir D; Rychtera, Mojmir; Melzoch, Karel; Guerrero Ochoa, Manuel R

2012-01-01

The influence of aeration on the fermentative activity of Kloeckera apiculata RIVE 9-2-1 was studied in order to evaluate the production of metabolites of the fermentation. To achieve this, the strain was cultured in Erlenmeyer flasks containing sterilized and aroma removed apple juice, and the chemical compounds produced during fermentation in shaken (200 min-1) and static (without agitation) cultivation were determined. The results showed that the agitation of the culture medium increases production of higher alcohols (till 591.0 mg/L) compared to static cultivation, whereas on the contrary, the production of acetic acid, ethyl acetate and glycerol (260.0 ± 11.0 mg/L, 196.0 ± 10.0 mg/L y 2.6±0.2 g/L) were higher compared to shaken cultivation (222.0 ± 8.0 mg/L, 96.0 ± 4.5 mg/L and 1.8 ± 0.2 g/L) respectively. Batch cultivations carried out in bioreactor with air flux of 25 l/h reported a growth rate μ of 0.17 h-1, production of ethanol (12.5 ± 2.0 g/L) and other compounds typically produced during alcoholic fermentation. The concentration of dissolved oxygen in the fermentation medium affects its metabolism thus; insufficient amounts of oxygen would provoke a respirofermentative metabolism. The best results in terms of organoleptic quality of the fermented beverage regarding to aroma, taste and flavor was obtained when fermented in static cultivation. The control of aeration during fermentation can be used to control the synthesis of chemical compounds of sensory impact in the production of fermented beverages.

Fermentation process for alcoholic beverage production from mahua ...

African Journals Online (AJOL)

Ezedom Theresa

2013-09-25

Sep 25, 2013 ... Key words: Madhuca indica, ethanol, reducing sugar, fermentation. ... The mahua flowers obtained were cleaned and dried in hot air oven at 60°C ... methanol in the fermented sample was determined with the help of.

Identification of the potential inhibitors of malolactic fermentation in wines

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Renata Vieira da MOTA

2017-10-01

Full Text Available Abstract This exploratory work aims to identify the potential inhibitors of lactic bacterial growth and to propose enological practices to guarantee the occurrence of spontaneous malolactic fermentation (MLF in wines from traditional and double-pruning management harvests in southeast Brazil. One white wine from a summer harvest and one red wine from a winter harvest that failed to complete MLF were utilized as comparative models to identify inhibitor compounds to lactic bacteria. Wine composition, alcoholic-fermentation temperature and bacterial strain contribute to the success or failure of MLF. Temperatures below 12 °C during alcoholic fermentation decrease lactic bacterial metabolism and may impair the bacteria’s growth after yeast cells lysis. A must pH below 3.2 in a summer harvest impairs bacterial growth, and the association of low pH with a free-SO2 concentration above 10 mg L-1 may inhibit MLF. For grapes with a high sugar content, harvested in the winter cycle, enologists should keep the alcohol content below 15% and control the alcoholic-fermentation temperature.

Saccharomyces cerevisiae in the Production of Fermented Beverages

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Graeme M Walker

2016-11-01

Full Text Available Alcoholic beverages are produced following the fermentation of sugars by yeasts, mainly (but not exclusively strains of the species, Saccharomyces cerevisiae. The sugary starting materials may emanate from cereal starches (which require enzymatic pre-hydrolysis in the case of beers and whiskies, sucrose-rich plants (molasses or sugar juice from sugarcane in the case of rums, or from fruits (which do not require pre-hydrolysis in the case of wines and brandies. In the presence of sugars, together with other essential nutrients such as amino acids, minerals and vitamins, S. cerevisiae will conduct fermentative metabolism to ethanol and carbon dioxide (as the primary fermentation metabolites as the cells strive to make energy and regenerate the coenzyme NAD+ under anaerobic conditions. Yeasts will also produce numerous secondary metabolites which act as important beverage flavour congeners, including higher alcohols, esters, carbonyls and sulphur compounds. These are very important in dictating the final flavour and aroma characteristics of beverages such as beer and wine, but also in distilled beverages such as whisky, rum and brandy. Therefore, yeasts are of vital importance in providing the alcohol content and the sensory profiles of such beverages. This Introductory Chapter reviews, in general, the growth, physiology and metabolism of S. cerevisiae in alcoholic beverage fermentations.

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...

The application of non-Saccharomyces yeast in fermentations with limited aeration as a strategy for the production of wine with reduced alcohol content.

Science.gov (United States)

Contreras, A; Hidalgo, C; Schmidt, S; Henschke, P A; Curtin, C; Varela, C

2015-07-16

High alcohol concentrations reduce the complexity of wine sensory properties. In addition, health and economic drivers have the wine industry actively seeking technologies that facilitate the production of wines with lower alcohol content. One of the simplest approaches to achieve this aim would be the use of wine yeast strains which are less efficient at transforming grape sugars into ethanol, however commercially available wine yeasts produce very similar ethanol yields. Non-conventional yeast, in particular non-Saccharomyces species, have shown potential for producing wines with lower alcohol content. These yeasts are naturally present in the early stages of fermentation but in general are not capable of completing alcoholic fermentation. We have evaluated 48 non-Saccharomyces isolates to identify strains that, with limited aeration and in sequential inoculation regimes with S. cerevisiae, could be used for the production of wine with lower ethanol concentration. Two of these, Torulaspora delbrueckii AWRI1152 and Zygosaccharomyces bailii AWRI1578, enabled the production of wine with reduced ethanol concentration under limited aerobic conditions. Depending on the aeration regime T. delbrueckii AWRI1152 and Z. bailii AWRI1578 showed a reduction in ethanol concentration of 1.5% (v/v) and 2.0% (v/v) respectively, compared to the S. cerevisiae anaerobic control. Copyright © 2015 Elsevier B.V. All rights reserved.

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. Copyright © 2011. Published by Elsevier B.V.

[Process development for continuous ethanol fermentation by the flocculating yeast under stillage backset conditions].

Science.gov (United States)

Zi, Lihan; Liu, Chenguang; Bai, Fengwu

2014-02-01

Propionic acid, a major inhibitor to yeast cells, was accumulated during continuous ethanol fermentation from corn meal hydrolysate by the flocculating yeast under stillage backset conditions. Based on its inhibition mechanism in yeast cells, strategies were developed for alleviating this effect. Firstly, high temperature processes such as medium sterilization generated more propionic acid, which should be avoided. Propionic acid was reduced significantly during ethanol fermentation without medium sterilization, and concentrations of biomass and ethanol increased by 59.3% and 7.4%, respectively. Secondly, the running time of stillage backset should be controlled so that propionic acid accumulated would be lower than its half inhibition concentration IC50 (40 mmol/L). Finally, because low pH augmented propionic acid inhibition in yeast cells, a higher pH of 5.5 was validated to be suitable for ethanol fermentation under the stillage backset condition.

Continuous dark fermentative hydrogen production by mesophilic microflora: Principles and progress

Energy Technology Data Exchange (ETDEWEB)

Hawkes, Freda R.; Hussy, Ines; Kyazze, Godfrey; Dinsdale, Richard; Hawkes, Dennis L. [School of Applied Sciences, University of Glamorgan, Pontypridd RCT CF37 1DL (United Kingdom)

2007-02-15

Continuous, dark fermentative hydrogen production technology using mixed microflora at mesophilic temperatures may be suitable for commercial development. Clostridial-based cultures from natural sources have been widely used, but more information on the need for heat treatment of inocula and conditions leading to germination and sporulation are required. The amount of nutrients given in the literature vary widely. Hydrogen production is reported to proceed without methane production in the reactor in the pH range 4.5-6.7, with hydraulic retention times optimally between a few hours and 3 days depending on substrate. Higher substrate concentrations should be more energy-efficient but there are product inhibition limitations, for example from unionised butyric acid. Inhibition by H{sub 2} can be reduced by stirring, sparging or extraction through membranes. Of the reactor types investigated, while granules have the best performance with soluble substrate, for particulate feedstock biofilm reactors or continuous stirred tank reactors may be most successful. A second stage is required to utilise the fermentation end products which, when cost-effective reactors are developed, may be photofermentation or microbial fuel cell technologies. Anaerobic digestion is a currently-available technology and the two-stage process is reported to give greater conversion efficiency than anaerobic digestion alone. (author)

Saccharomyces cerevisiae Fermentation Effects on Pollen: Archaeological Implications

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Crystal A. Dozier

2016-03-01

Full Text Available Pollen is the reproductive agent of flowering plants; palynology is utilized by archaeologists because sporopollenin, a major component in the exine of pollen grains, is resistant to decay and morphologically distinctive. Wine, beer, and mead have been identified in the archaeological record by palynological assessment due to indicator species or due to a pollen profile similar to that recovered from honey, a common source of sugar in a variety of fermented beverages. While most palynologists have assumed that pollen grains are resistant to alcoholic fermentation, a recent study in food science implies that pollen is a yeast nutrient because pollen-enriched meads produce more alcohol. The experiment presented here explores the potential distortion of the pollen record through fermentation by brewing a traditional, pollen-rich mead with Saccharomyces cerevisiae. In this experiment, the pollen grains did not undergo any discernible morphological changes nor were distorted in the pollen profile. Any nutrition that the yeast garners from the pollen therefore leaves sporopollenin intact. These results support palynological research on residues of alcoholic beverages and confirms that the fermentation process does not distort the pollen profile of the original substance. The paper concludes with the potential and limits of palynological study to assess fermentation within the archaeological record.

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

Multi-stage high cell continuous fermentation for high productivity and titer.

Science.gov (United States)

Chang, Ho Nam; Kim, Nag-Jong; Kang, Jongwon; Jeong, Chang Moon; Choi, Jin-dal-rae; Fei, Qiang; Kim, Byoung Jin; Kwon, Sunhoon; Lee, Sang Yup; Kim, Jungbae

2011-05-01

We carried out the first simulation on multi-stage continuous high cell density culture (MSC-HCDC) to show that the MSC-HCDC can achieve batch/fed-batch product titer with much higher productivity to the fed-batch productivity using published fermentation kinetics of lactic acid, penicillin and ethanol. The system under consideration consists of n-serially connected continuous stirred-tank reactors (CSTRs) with either hollow fiber cell recycling or cell immobilization for high cell-density culture. In each CSTR substrate supply and product removal are possible. Penicillin production is severely limited by glucose metabolite repression that requires multi-CSTR glucose feeding. An 8-stage C-HCDC lactic acid fermentation resulted in 212.9 g/L of titer and 10.6 g/L/h of productivity, corresponding to 101 and 429% of the comparable lactic acid fed-batch, respectively. The penicillin production model predicted 149% (0.085 g/L/h) of productivity in 8-stage C-HCDC with 40 g/L of cell density and 289% of productivity (0.165 g/L/h) in 7-stage C-HCDC with 60 g/L of cell density compared with referring batch cultivations. A 2-stage C-HCDC ethanol experimental run showed 107% titer and 257% productivity of the batch system having 88.8 g/L of titer and 3.7 g/L/h of productivity. MSC-HCDC can give much higher productivity than batch/fed-batch system, and yield a several percentage higher titer as well. The productivity ratio of MSC-HCDC over batch/fed-batch system is given as a multiplication of system dilution rate of MSC-HCDC and cycle time of batch/fed-batch system. We suggest MSC-HCDC as a new production platform for various fermentation products including monoclonal antibody.

Filamentous fungal diversity and community structure associated with the solid state fermentation of Chinese Maotai-flavor liquor.

Science.gov (United States)

Chen, Bi; Wu, Qun; Xu, Yan

2014-06-02

Maotai-flavor liquor is produced by simultaneous saccharification and fermentation (SSF) process under solid state conditions, including Daqu (starter) making, stacking fermentation and alcohol fermentation stages. Filamentous fungi produce many enzymes to degrade the starch material into fermentable sugar during liquor fermentation. This study investigated the filamentous fungal community associated with liquor making process. Eight and seven different fungal species were identified by using culture-dependent and -independent method (PCR-denaturing gradient gel electrophoresis, DGGE) analyses, respectively. The traditional enumeration method showed that Daqu provided 7 fungal species for stacking fermentation. The total population of filamentous fungi increased from 3.4 × 10(3)cfu/g to 1.28 × 10(4)cfu/g in the first 3 days of stacking fermentation, and then decreased till the end. In alcohol fermentation in pits, the population continuously decreased and few fungal species survived (lower than 1 × 10(3)cfu/g) after 10 days. Therefore, stacking fermentation is an essential stage for the growth of filamentous fungi. Paecilomyces variotii, Aspergillus oryzae and Aspergillus terreus were detected by both methods, and P. variotii and A. oryzae were the predominant species. Meanwhile, P. variotii possessed the highest glucoamylase (3252 ± 526 U/g) and A. oryzae exhibited the highest α-amylase (1491 ± 324 U/g) activity among the cultivable fungal species. Furthermore, the variation of starch and reducing sugar content was consistent with the growth of P. variotii and A. oryzae in Zaopei (fermented grains) during stacking fermentation, which implied that the two filamentous fungi played an important role in producing amylase for hydrolyzing the starch. Copyright © 2014 Elsevier B.V. All rights reserved.

Addition of wood chips in red wine during and after alcoholic fermentation: differences in color parameters, phenolic content and volatile composition

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Maria Kyraleou

2016-12-01

Full Text Available The effect of the time of wood chip addition on phenolic content, color parameters and volatile composition of a red wine made by a native Greek variety (Agiorgitiko was evaluated. For this purpose, chips from American, French, Slavonia oak and Acacia were added in the wine during and after fermentation. Various chemical parameters of wines were studied after one, two and three months of contact with chips. The results showed that the addition of oak chips during alcoholic fermentation did not favor ellagitannin extraction and the reactions involved in tannin condensation and anthocyanin stabilization. Moreover, wines fermented with wood chips contained higher contents of whiskey lactones, eugenol, ethyl vanillate and acetate esters while their ethyl ester content was lower compared with the wines where chip addition took place after fermentation. Practical Application: The outcomes of this study would be of practical interest to winemakers since they could improve the control over the wood extraction process. When chips are added after fermentation wines seem to have a greater ageing potential compared to the wines fermented with chips due to their higher ellagitannin content and enhanced condensation reactions. On the other hand, color stabilization and tannin polymerization occur faster when chips are added during fermentation resulting in shorter ageing periods suitable for early consumed wines.

From Sugar of Grape to Alcohol of Wine: Sensorial Impact of Alcohol in Wine

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António M. Jordão

2015-11-01

Full Text Available The quality of grapes, as well as wine quality, flavor, stability, and sensorial characteristics depends on the content and composition of several different groups of compounds from grapes. One of these groups of compounds are sugars and consequently the alcohol content quantified in wines after alcoholic fermentation. During grape berry ripening, sucrose transported from the leaves is accumulated in the berry vacuoles as glucose and fructose. The wine alcohol content continues to be a challenge in oenology, as it is also the study of the role of chemosensory factors in alcohol intake and consumer preferences. Several technical and scientific advances have occurred in recent years, such as identification of receptors and other important molecules involved in the transduction mechanisms of flavor. In addition, consumers know that wines with high alcohol content can causes a gustatory disequilibrium affecting wine sensory perceptions leading to unbalanced wines. Hence, the object of this review is to enhance the knowledge on wine grape sugar composition, the alcohol perception on a sensorial level, as well as several technological practices that can be applied to reduce the wine alcohol content.

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

Outcome of alcohol dependence: The role of continued care

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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.

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.)

The alcohol dehydrogenase system in the xylose-fermenting yeast Candida maltosa.

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Yuping Lin

2010-07-01

Full Text Available The alcohol dehydrogenase (ADH system plays a critical role in sugar metabolism involving in not only ethanol formation and consumption but also the general "cofactor balance" mechanism. Candida maltosa is able to ferment glucose as well as xylose to produce a significant amount of ethanol. Here we report the ADH system in C. maltosa composed of three microbial group I ADH genes (CmADH1, CmADH2A and CmADH2B, mainly focusing on its metabolic regulation and physiological function.Genetic analysis indicated that CmADH2A and CmADH2B tandemly located on the chromosome could be derived from tandem gene duplication. In vitro characterization of enzymatic properties revealed that all the three CmADHs had broad substrate specificities. Homo- and heterotetramers of CmADH1 and CmADH2A were demonstrated by zymogram analysis, and their expression profiles and physiological functions were different with respect to carbon sources and growth phases. Fermentation studies of ADH2A-deficient mutant showed that CmADH2A was directly related to NAD regeneration during xylose metabolism since CmADH2A deficiency resulted in a significant accumulation of glycerol.Our results revealed that CmADH1 was responsible for ethanol formation during glucose metabolism, whereas CmADH2A was glucose-repressed and functioned to convert the accumulated ethanol to acetaldehyde. To our knowledge, this is the first demonstration of function separation and glucose repression of ADH genes in xylose-fermenting yeasts. On the other hand, CmADH1 and CmADH2A were both involved in ethanol formation with NAD regeneration to maintain NADH/NAD ratio in favor of producing xylitol from xylose. In contrast, CmADH2B was expressed at a much lower level than the other two CmADH genes, and its function is to be further confirmed.

Effects of fermentation by Saccharomyces cerevisiae and ...

African Journals Online (AJOL)

yassine

2013-02-13

Feb 13, 2013 ... Full Length Research Paper. Effect of Saccharomyces cerevisiae fermentation on the ... 2003). Besides, several alcoholic beverages such as wine or liqueurs are obtained from fruit juices fermented by Saccharomyces ..... (2003). Kinetics of pigment release from hairy root cultures of Beta vulgaris under the ...

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...

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.

Effect of operating conditions on the development of microflora in the fermentation of beet molasses

Energy Technology Data Exchange (ETDEWEB)

Kinzburskaya, F M; Zaprudnova, E P

1955-01-01

The process of beet-molasses fermentation for making industrial alcohol is influenced by a series of conditions among which are: the quality of the wort, the temperature of fermentation, the amount of the products formed by the activity of the yeast, and the microflora of the mass. The scope of the present work covers the influence of the following: (a) the concentation and the acidity of the wort; (b the alcohol content of the fermenting material; (c) the amount of starting yeast added; (d) the temperature maintained. Results are shown condensed in 23 plots. They are summarized by the authors as optimum conditions for fermentation: high concentrations of wort, a high concentration of alcohol in the early stages of fermentation,and high amounts of starting yeast.

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.

Formaldehyde as an antiseptic in the production of alcohol from molasses

Energy Technology Data Exchange (ETDEWEB)

Rosa, V J; Stros, F

1962-01-01

The effect of formaldehyde as an antiseptic for the noncontaminated alcohol fermentation of molasses was examined with five different yeasts mash batches containing formaldehyde 0.01%. Following 24 hour cultivation, increase in the activity of formaldehyde-inoculated mash was lowered by 47%; the formaldehyde decreased the alcohol fermentation and lessened the rate of fermentation of sugar by 20% in noncontaminated mash. The decrease in the fermentation rate was also observed during the entire course of fermentation. On the other hand, formaldehyde addition to molasses contaminated with lactic acid bacteria accelerated the fermentation rate.

Quality and Composition of Red Wine Fermented with Schizosaccharomyces pombe as Sole Fermentative Yeast, and in Mixed and Sequential Fermentations with Saccharomyces cerevisiae

Directory of Open Access Journals (Sweden)

Felipe Palomero

2014-01-01

Full Text Available This work examines the physiology of Schizosaccharomyces pombe (represented by strain 938 in the production of red wine, as the sole fermentative yeast, and in mixed and sequential fermentations with Saccharomyces cerevisiae 796. For further comparison, fermentations in which Saccharomyces cerevisiae was the sole fermentative yeast were also performed; in these fermentations a commercial lactic acid bacterium was used to perform malolactic fermentation once alcoholic fermentation was complete (unlike S. cerevisiae, the Sc. pombe performs maloalcoholic fermentation and therefore removes malic acid without such help. Relative density, acetic, malic and pyruvic acid concentrations, primary amino nitrogen and urea concentrations, and pH of the musts were measured over the entire fermentation period. In all fermentations in which Sc. pombe 938 was involved, nearly all the malic acid was consumed from an initial concentration of 5.5 g/L, and moderate acetic acid concentrations below 0.4 g/L were formed. The urea content of these wines was notably lower, showing a tenfold reduction when compared with those that were made with S. cerevisiae 796 alone. The sensorial properties of the different final wines varied widely. The wines fermented with Sc. pombe 938 had maximum aroma intensity and quality, and they were preferred by the tasters.

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

International Nuclear Information System (INIS)

Buratti, S.; Ballabio, D.; Giovanelli, G.; Dominguez, C.M. Zuluanga; Moles, A.; Benedetti, S.; Sinelli, N.

2011-01-01

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

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

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

Combined effects of nutrients and temperature on the production of fermentative aromas by Saccharomyces cerevisiae during wine fermentation.

Science.gov (United States)

Rollero, Stéphanie; Bloem, Audrey; Camarasa, Carole; Sanchez, Isabelle; Ortiz-Julien, Anne; Sablayrolles, Jean-Marie; Dequin, Sylvie; Mouret, Jean-Roch

2015-03-01

Volatile compounds produced by yeast during fermentation greatly influence the organoleptic qualities of wine. We developed a model to predict the combined effects of initial nitrogen and phytosterol content and fermentation temperature on the production of volatile compounds. We used a Box-Behnken design and response surface modeling to study the response of Lalvin EC1118® to these environmental conditions. Initial nitrogen content had the greatest influence on most compounds; however, there were differences in the value of fermentation parameters required for the maximal production of the various compounds. Fermentation parameters affected differently the production of isobutanol and isoamyl alcohol, although their synthesis involve the same enzymes and intermediate. We found differences in regulation of the synthesis of acetates of higher alcohols and ethyl esters, suggesting that fatty acid availability is the main factor influencing the synthesis of ethyl esters whereas the production of acetates depends on the activity of alcohol acetyltransferases. We also evaluated the effect of temperature on the total production of three esters by determining gas-liquid balances. Evaporation largely accounted for the effect of temperature on the accumulation of esters in liquid. Nonetheless, the metabolism of isoamyl acetate and ethyl octanoate was significantly affected by this parameter. We extended this study to other strains. Environmental parameters had a similar effect on aroma production in most strains. Nevertheless, the regulation of the synthesis of fermentative aromas was atypical in two strains: Lalvin K1M® and Affinity™ ECA5, which produces a high amount of aromatic compounds and was obtained by experimental evolution.

Biological fermentative hydrogen production from olive pulp at 35 degrees C

Energy Technology Data Exchange (ETDEWEB)

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

2004-07-01

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

Comparing a Dynamic Fed-Batch and a Continuous Steady-State Simulation of Ethanol Fermentation in a Distillery to a Stoichiometric Conversion Simulation

Directory of Open Access Journals (Sweden)

G.C. Fonseca

Full Text Available Abstract An autonomous sugarcane bioethanol plant was simulated in EMSO software, an equation oriented process simulator. Three types of fermentation units were simulated: a six parallel fed-batch reactor system, a set of four CSTR in steady state and one consisting of a single stoichiometric reactor. Stoichiometric models are less accurate than kinetic-based fermentation models used for fed-batch and continuous fermenter simulations, since they do not account for inhibition effects and depend on a known conversion rate of reactant to be specified instead. On the other hand, stoichiometric models are faster and simpler to converge. In this study it was found that the conversion rates of sugar for the fermentation systems analyzedwere predictable from information on the composition of the juice stream. Those rates were used in the stoichiometric model, which accurately reproduced the results from both the fed-batch and the continuous fermenter system.

Induction of simultaneous and sequential malolactic fermentation in durian wine.

Science.gov (United States)

Taniasuri, Fransisca; Lee, Pin-Rou; Liu, Shao-Quan

2016-08-02

This study represented for the first time the impact of malolactic fermentation (MLF) induced by Oenococcus oeni and its inoculation strategies (simultaneous vs. sequential) on the fermentation performance as well as aroma compound profile of durian wine. There was no negative impact of simultaneous inoculation of O. oeni and Saccharomyces cerevisiae on the growth and fermentation kinetics of S. cerevisiae as compared to sequential fermentation. Simultaneous MLF did not lead to an excessive increase in volatile acidity as compared to sequential MLF. The kinetic changes of organic acids (i.e. malic, lactic, succinic, acetic and α-ketoglutaric acids) varied with simultaneous and sequential MLF relative to yeast alone. MLF, regardless of inoculation mode, resulted in higher production of fermentation-derived volatiles as compared to control (alcoholic fermentation only), including esters, volatile fatty acids, and terpenes, except for higher alcohols. Most indigenous volatile sulphur compounds in durian were decreased to trace levels with little differences among the control, simultaneous and sequential MLF. Among the different wines, the wine with simultaneous MLF had higher concentrations of terpenes and acetate esters while sequential MLF had increased concentrations of medium- and long-chain ethyl esters. Relative to alcoholic fermentation only, both simultaneous and sequential MLF reduced acetaldehyde substantially with sequential MLF being more effective. These findings illustrate that MLF is an effective and novel way of modulating the volatile and aroma compound profile of durian wine. Copyright © 2016 Elsevier B.V. All rights reserved.

Association between modification of phenolic profiling and development of wine color during alcohol fermentation.

Science.gov (United States)

Li, Si-Yu; Liu, Pei-Tong; Pan, Qiu-Hong; Shi, Ying; Duan, Chang-Qing

2015-04-01

To solve the problem of wine color instability in western China, different additives (the maceration enzymes Vinozym G and Ex-color, yeasts VR5 and Red Star, and commercial tannins) were added during alcoholic fermentation of Syrah (Vitis vinifera L.). The phenolic profile and color characteristics of wine were examined using high performance liquid chromatography mass spectrometry and CIELAB, respectively. The results showed that the combination of the enzyme Ex-color with the Red Star yeast eased the release of non-anthocyanins from grape berries into wine, whereas the use of enzyme Vinozym G and VR5 yeast enhanced the concentration of anthocyanins and achieved a higher red hue (a* value) and a lower yellow hue (b* value) in the wine. The addition of commercial tannins greatly promoted the level of gallic acid in the wine and led to a relatively higher concentration of anthocyanins. Partial least-squares regression analysis was used to find out the major phenolics, which were in close relation with color parameters; principal component analysis was used to evaluate the contribution of different winemaking techniques to wine color. The combination of these 2 analytic methods indicated that Vinozym G and VR5 yeast together with commercial tannins should be an appropriate combination to enhance the stability of wine color during alcohol fermentation, which was related to a significant increase in cyanidin-3-O-(6-O-acetyl)-glucoside, cyanidin-3-O-(6-O-coumaryl)-glucoside, trans-peonidin-3-O-(6-O-coumaryl)-glucoside, trans-malvidin-3-O-(6-O-coumaryl)-glucoside, and malvidin-3-O-(6-O-acetyl)-glucoside-pyruvic acid, all of which played an important role in stabilizing wine color. © 2015 Institute of Food Technologists®

Continuous minimally-invasive alcohol monitoring using microneedle sensor arrays.

Science.gov (United States)

Mohan, A M Vinu; Windmiller, Joshua Ray; Mishra, Rupesh K; Wang, Joseph

2017-05-15

The present work describes an attractive skin-worn microneedle sensing device for the minimally invasive electrochemical monitoring of subcutaneous alcohol. The device consists of an assembly of pyramidal microneedle structures integrated with Pt and Ag wires, each with a microcavity opening. The microneedle aperture was modified by electropolymerizing o-phenylene diamine onto the Pt wire microtransducer, followed by the immobilization of alcohol oxidase (AOx) in an intermediate chitosan layer, along with an outer Nafion layer. The resulting microneedle-based enzyme electrode displays an interference-free ethanol detection in artificial interstitial fluid without compromising its sensitivity, stability and response time. The skin penetration ability and the efficaciousness of the biosensor performance towards subcutaneous alcohol monitoring was substantiated by the ex vivo mice skin model analysis. Our results reveal that the new microneedle sensor holds considerable promise for continuous non-invasive alcohol monitoring in real-life situations. Copyright © 2017 Elsevier B.V. All rights reserved.

Chemical Assessment of White Wine during Fermentation Process

Directory of Open Access Journals (Sweden)

Teodora Coldea

2014-05-01

Full Text Available There were investigated chemical properties of indigenous white wine varieties (Fetească albă, Fetească regală and Galbenă de Odobeşti during fermentation. The white wine making process took place at Wine Pilot Station of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. We aimed to monitorize the evolution of fermentation process parameters (temperature, alcohol content, and real extract and the quality of the bottled white wine (total acidity, alcohol content, total sulfur dioxide, total dry extract. The results obtained were in accordance to Romanian Legislation.

Yeast population dynamics reveal a potential 'collaboration' between Metschnikowia pulcherrima and Saccharomyces uvarum for the production of reduced alcohol wines during Shiraz fermentation.

Science.gov (United States)

Contreras, A; Curtin, C; Varela, C

2015-02-01

The wine sector is actively seeking strategies and technologies that facilitate the production of wines with lower alcohol content. One of the simplest approaches to achieve this aim would be the use of wine yeast strains which are less efficient at transforming grape sugars into ethanol; however, commercial wine yeasts have very similar ethanol yields. We recently demonstrated that Metschnikowia pulcherrima AWRI1149 was able to produce wine with reduced alcohol concentration when used in sequential inoculation with a wine strain of Saccharomyces cerevisiae. Here, different inoculation regimes were explored to study the effect of yeast population dynamics and potential yeast interactions on the metabolism of M. pulcherrima AWRI1149 during fermentation of non-sterile Shiraz must. Of all inoculation regimes tested, only ferments inoculated with M. pulcherrima AWRI1149 showed reduced ethanol concentration. Population dynamics revealed the presence of several indigenous yeast species and one of these, Saccharomyces uvarum (AWRI 2846), was able to produce wine with reduced ethanol concentration in sterile conditions. Both strains however, were inhibited when a combination of three non-Saccharomyces strains, Hanseniaspora uvarum AWRI863, Pichia kluyveri AWRI1896 and Torulaspora delbrueckii AWRI2845 were inoculated into must, indicating that the microbial community composition might impact on the growth of M. pulcherrima AWRI1149 and S. uvarum AWRI 2846. Our results indicate that mixed cultures of M. pulcherrima AWRI1149 and S. uvarum AWRI2846 enable an additional reduction of wine ethanol concentration compared to the same must fermented with either strain alone. This work thus provides a foundation to develop inoculation regimes for the successful application of non-cerevisiae yeast to the production of wines with reduced alcohol.

Residential environments, alcohol advertising, and initiation and continuation of alcohol consumption among adolescents in urban Taiwan: A prospective multilevel study.

Science.gov (United States)

Chen, Yen-Tyng; Cooper, Hannah L F; Windle, Michael; Haardörfer, Regine; Crawford, Natalie D; Chen, Wei J; Chen, Chuan-Yu

2016-12-01

Research indicates that place characteristics and the media environment are important contextual determinants of underage drinking behaviors in Western countries, but it is unknown whether these exposures influence adolescent alcohol consumption outside Western contexts, including in Asia׳s emerging global alcohol markets. Guided by the social ecological framework, we prospectively investigated the influences of place characteristics and alcohol advertising on initiation and continuation of alcohol consumption among adolescents in Taipei, Taiwan. Data on individual-level characteristics, including alcohol use behaviors and perceived exposure to alcohol advertising, were obtained from two waves of a longitudinal school-based study through a stratified probability sampling method in 2010 (Grade 7/Grade 8, aged 13-14 years old) and 2011-2012 (Grade 9, aged 15 years old) from 1795 adolescents residing in 22 of 41 districts in Taipei. Data on district-level characteristics were drawn from administrative sources and Google Street View virtual audit to describe districts where adolescents lived at baseline. Hierarchical generalized linear models tested hypotheses about the associations of place characteristics and perceived alcohol advertising with underage drinking, with stratification by baseline lifetime alcohol consumption. Among alcohol-naïve adolescents, lower district-level economic disadvantage, a higher proportion of betel nut kiosks (a relatively unregulated alcohol source) compared to off-premises alcohol outlets, and exposure to television-based alcohol advertising predicted increased likelihood of alcohol initiation at one-year follow-up. Among alcohol-experienced adolescents, greater spatial access to off-premises alcohol outlets, and lower access to metro rapid transportation (MRT) and to temples were found to predict a subsequent increased likelihood of continued alcohol use. Parental drinking moderated the relationship between district-level violent

Use of a biparticle fluidized-bed bioreactor for the continuous and simultaneous fermentation and purification of lactic acid

Energy Technology Data Exchange (ETDEWEB)

Kaufman, E. N.; Cooper, S. P.; Clement, S. L.; Little, M. H.

1994-05-01

A continuous biparticle fluidized bed reactor is developed for the simultaneous fermentation and purification of lactic acid. In this processing scheme, bacteria are immobilized in gelatin beads and are fluidized in a columnar reactor. Solid particles with sorbent capacity for the product are introduced at the top of the reactor, and fall counter currently to the biocatalyst, effecting in situ removal of the inhibitory product, while also controlling reactor pH at optimal levels. Initial long-term fermentation trials using immobilized Lactobacillus delbreuckii have demonstrated a 12 fold increase in volumetric productivity during adsorbent addition as opposed to control fermentations in the same reactor. Unoptimized regeneration of the loaded sorbent has effected at least an 8 fold concentration of lactic acid, and a 68 fold enhancement in separation from glucose compared to original levels in the fermentation broth. The benefits of this reactor system as opposed to conventional batch fermentation are discussed in terms of productivity and process economics.

Mystery behind Chinese liquor fermentation

OpenAIRE

Jin, Guangyuan; Zhu, Yang; Xu, Yan

2017-01-01

Background Chinese liquor, a very popular fermented alcoholic beverage with thousands of years’ history in China, though its flavour formation and microbial process have only been partly explored, is facing the industrial challenge of modernisation and standardisation for food quality and safety as well as sustainability. Meanwhile, the hidden knowledge behind the complicated and somehow empirical solid-state fermentation process of Chinese liquor can enrich the food sector to improve our qua...

Microbial electrode sensor for alcohols

Energy Technology Data Exchange (ETDEWEB)

Hikuma, M [Ajinomoto Co., Inc., Kawasaki, Japan; Kubo, T; Yasuda, T; Karube, I; Suzuki, S

1979-10-01

A microbial electrode consisting of immobilized microorganisms, a gas permeable Teflon membrane, and an oxygen electrode was prepared for the continuous determination of methyl and ethyl alcohols. Immobilized Trichosporon brassicae was employed for a microbial electrode sensor for ethyl alcohol. When a sample solution containing ethyl alcohol was injected into a microbial electrode system, the current of the electrode decreased markedly with time until a steady state was reached. The response time was within 10 min by the steady state method and within 6 min by the pulse method. A linear relationship was observed between the current decrease and the concentration of ethyl alcohol below 22.5 mg/liter. The current was reproducible within +- 6% of the relative error when a sample solution containing 16.5 mg/liter ethyl alcohol. The standard deviation was 0.5 mg/liter in 40 experiments. The selectivity of the microbial electrode sensor for ethyl alcohol was satisfactory. The microbial electrode sensor was applied to a fermentation broth of yeasts and satisfactory comparative results were obtained (correlation coefficient 0.98). The current output of the microbial electrode sensor was almost constant for more than three weeks and 2100 assays. A microbial electrode sensor using immobilized bacteria for methyl alcohol was also described.

Optimisation of Lab-Scale Continuous Alcohol-Free Beer Production

Czech Academy of Sciences Publication Activity Database

Lehnert, R.; Novák, Pavel; Macieira, F.; Kuřec, M.; Teixeira, J.A.; Brányik, T.

2009-01-01

Roč. 27, č. 4 (2009), s. 267-275 ISSN 1212-1800 Institutional research plan: CEZ:AV0Z40720504 Keywords : alcohol-free beer * continuous reactor * immobilised yeast Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 0.602, year: 2009

Degradation of Aflatoxin B1 during the Fermentation of Alcoholic Beverages

Directory of Open Access Journals (Sweden)

Naoki Mochizuki

2013-06-01

Full Text Available 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.

Conditions for saccharification and fermentation of manioc mash

Energy Technology Data Exchange (ETDEWEB)

Nguen, D.C.; Velikaya, E.I.

1972-01-01

Saccharification time of manioc starch, proportion of enzyme preparations added (obtained from Aspergillus oryzae and Aspergillus awamori) and the effect of a nitrogenous medium on fermentation were studied. Extension of saccharification time led to inactivation of the enzymes which adversely affected fermentation. In 5 minutes saccharification with Aspergillus oryzae of material pureed by boiling, the alcohol yield was 38.71/ton of starch higher than when a 60-minute saccharification period was used. Saccharification with a combination of the 2 moulds produced a higher alcohol yield than when only Aspergillus oryzae was used. A high glucoamylase content in the mash gave a high alcohol yield. Nitrogenous substances must be added to the manioc mash to provide for the nutrition of the yeast cells; carbamide proved most efficient.

Complex permittivity measurement at millimetre-wave frequencies during the fermentation process of Japanese sake

International Nuclear Information System (INIS)

Kouzai, Masaki; Nishikata, Atsuhiro; Fukunaga, Kaori; Miyaoka, Shunsuke

2007-01-01

Various chemical reactions occur simultaneously in barrels during the fermentation processes of alcoholic beverages. Chemical analyses are employed to monitor the change in chemical components, such as glucose and ethyl alcohol. The tests are carried out with extracted specimens, are costly and require time. We have developed a permittivity measurement system for liquid specimens in the frequency range from 2.6 to 50 GHz, and applied the system to fermentation monitoring. Experimental results proved that the observed change in complex permittivity suggests a decrease in the amount of glucose and an increase in alcohol content, which are the key chemical components during the fermentation process

Residential environments, alcohol advertising, and initiation and continuation of alcohol consumption among adolescents in urban Taiwan: A prospective multilevel study

Directory of Open Access Journals (Sweden)

Yen-Tyng Chen

2016-12-01

Full Text Available Background: Research indicates that place characteristics and the media environment are important contextual determinants of underage drinking behaviors in Western countries, but it is unknown whether these exposures influence adolescent alcohol consumption outside Western contexts, including in Asia׳s emerging global alcohol markets. Guided by the social ecological framework, we prospectively investigated the influences of place characteristics and alcohol advertising on initiation and continuation of alcohol consumption among adolescents in Taipei, Taiwan. Methods: Data on individual-level characteristics, including alcohol use behaviors and perceived exposure to alcohol advertising, were obtained from two waves of a longitudinal school-based study through a stratified probability sampling method in 2010 (Grade 7/Grade 8, aged 13-14 years old and 2011-2012 (Grade 9, aged 15 years old from 1795 adolescents residing in 22 of 41 districts in Taipei. Data on district-level characteristics were drawn from administrative sources and Google Street View virtual audit to describe districts where adolescents lived at baseline. Hierarchical generalized linear models tested hypotheses about the associations of place characteristics and perceived alcohol advertising with underage drinking, with stratification by baseline lifetime alcohol consumption. Results: Among alcohol-naïve adolescents, lower district-level economic disadvantage, a higher proportion of betel nut kiosks (a relatively unregulated alcohol source compared to off-premises alcohol outlets, and exposure to television-based alcohol advertising predicted increased likelihood of alcohol initiation at one-year follow-up. Among alcohol-experienced adolescents, greater spatial access to off-premises alcohol outlets, and lower access to metro rapid transportation (MRT and to temples were found to predict a subsequent increased likelihood of continued alcohol use. Parental drinking moderated the

Indigenous and inoculated yeast fermentation of gabiroba (Campomanesia pubescens) pulp for fruit wine production.

Science.gov (United States)

Duarte, Whasley Ferreira; Dias, Disney Ribeiro; de Melo Pereira, Gilberto Vinicius; Gervásio, Ivani Maria; Schwan, Rosane Freitas

2009-04-01

The objectives of this study were to evaluate the potential of gabiroba Campomanesia pubescens (DC) O. Berg in the production of a beverage fermented using selected and wild yeasts from indigenous fermentation, analyze the volatile compounds profile present during the process of fermentation, and evaluate the sensory quality of the final beverage produced. Throughout the process of fermentation, when Saccharomyces cerevisiae UFLA CA 1162 was inoculated, there were stable viable populations around 9 log cells ml(-1). During indigenous fermentation, yeast population increased from 3.7 log CFU ml(-1) to 8.1 log CFU ml(-1) after 14 days. The diversity and dynamics of the yeast population during indigenous fermentation observed by PFGE analysis showed five different karyotyping profiles in the first days of fermentation. After the seventh day, there was a higher frequency of a similar S. cerevisiae profile. The yeast non-Saccharomyces were identified by sequencing of the ITS region as Candida quercitrusa and Issatchenkia terricola. Inoculated fermentations yielded a higher amount of alcohol than indigenous ones, indicating the efficiency of selected strains. There was also a greater concentration of higher alcohols, which are usually responsible for the flavor found in alcoholic beverages. Based on the characteristics of the pulp and acceptance in the sensory analysis, gabiroba fruits showed good potential for use in the production of fermented beverage.

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

Copper Tolerance and Biosorption of Saccharomyces cerevisiae during Alcoholic Fermentation.

Directory of Open Access Journals (Sweden)

Xiang-Yu Sun

Full Text Available 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.

Lactic acid fermentation of cassava dough into agbelima.

Science.gov (United States)

Amoa-Awua, W K; Appoh, F E; Jakobsen, M

1996-08-01

The souring of cassava dough during fermentation into the fermented cassava meal, agbelima, was investigated. Four different types of traditional inocula were used to ferment the dough and increases in titrable acidity expressed as lactic acid from 0.31-0.38 to 0.78-0.91% (w/w) confirmed the fermentation to be a process of acidification. The microflora of all inocula and fermenting dough contained high counts of lactic acid bacteria, 10(8)-10(9) cfu/g in all inocula and 10(7)-10(8), 10(8)-10(9) and 10(9) cfu/g at 0, 24 and 48 h in all fermentations. Lactobacillus plantarum was the dominant species of lactic acid bacteria during all types of fermentation accounting for 51% of 171 representative isolates taken from various stages of fermentation. Other major lactic acid bacteria found were Lactobacillus brevis, 16%, Leuconostoc mesenteroides, 15% and some cocci including Streptococcus spp. whose numbers decreased with fermentation time. The lactic acid bacteria were responsible for the souring of agbelima through the production of lactic acid. All L. plantarum, L. brevis and L. mesenteroides isolates examined demonstrated linamarase as well as other enzymatic activities but did not possess tissue degrading enzymes like cellulase, pectin esterase and polygalacturonase. The aroma profile of agbelima did not vary with the type of inoculum used and in all samples the build-up of aroma compounds were dominated by a non-identified low molecular weight alcohol, 1-propanol, isoamyl alcohol, ethyl acetate, 3-methyl-1-butanol and acetoin. Substantial reductions occurred in the levels of cyanogenic compounds present in cassava during fermentation into agbelima and detoxification was enhanced by the use of inoculum.

Production and Characterization of a Distilled Alcoholic Beverage Obtained by Fermentation of Banana Waste (Musa cavendishii from Selected Yeast

Directory of Open Access Journals (Sweden)

Mara Eli de Matos

2017-11-01

Full Text Available Banana is one of the most important fruits in the Brazilian diet and is mainly consumed naturally. Losses from crop to final consumer are high and estimated in about 30%. The aim of this work was to elaborate a distilled alcoholic beverage from discarded banana and to compare with commercial trademarks. Initially, yeast strains were isolated from banana fruit and characterized by their production of volatile aroma compounds. The highest aroma-producing yeast isolate was identified by ITS-rRNA gene sequencing as Pichia kluyveri. Pasteurized banana pulp and peel was fermented by the selected P. kluyveri at approximately 107 cells/mL. The sugars were converted quickly, and a high ethanol concentration (413 mg/L was achieved after 24 h of fermentation. The fermented banana must was distilled in a Femel Alambic, and the head, heart and tail fractions were collected. The banana brandy produced had highest concentration of volatile compounds compared to trademarks, such as isoamyl acetate (13.5 mg/L, ethyl hexanoate (0.8 mg/L and others. The results showed that whole banana must could be a good substrate for fermentation and distillation, and the sensory analysis performed revealed that the produced beverage had good acceptance by the tasters. This study demonstrates the potential of banana as a possible alternative to reduce waste and increase income to farmers.

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

Energy Technology Data Exchange (ETDEWEB)

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

1996-12-31

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

Adaptive control of biomass and substrate concentration in a continuous-flow. Fermentation process

Energy Technology Data Exchange (ETDEWEB)

Chamilothoris, G; Sevely, Y; Sevely, Y

1988-01-01

This paper presents a simple adaptive control scheme for the simultaneous regulation of biomass and substrate concentration in a continuous fermentation process. The proposed algorithm includes the on-line estimation of a time-varying parameter (namely the specific growth rate) and two cascaded regulators of self-tuning inspiration. Convergence of the control algorithm, in the BIBO sense, is theoretically established and its effectiveness is illustrated by simulation examples.

Impact of initial lipid content and oxygen supply on alcoholic fermentation in champagne-like musts.

Science.gov (United States)

Ochando, Thomas; Mouret, Jean-Roch; Humbert-Goffard, Anne; Sablayrolles, Jean-Marie; Farines, Vincent

2017-08-01

Available nitrogen, lipids, or oxygen are nutrients with major impact on the kinetics of winemaking fermentation. Assimilable nitrogen is usually the growth-limiting nutrient which availability determines the fermentation rate and therefore the fermentation duration. In some particular cases, as in Champagne, grape musts have high available nitrogen content and low turbidity, i.e., below 50 Nephelometric Turbidity Unit (NTU). In the case of low turbidity, the availability of lipids, particularly phytosterols, becomes limiting. In this situation, control of oxygenation, which is necessary for lipid synthesis by yeast, is particularly crucial during fermentation. To mimic and understand these situations, a synthetic medium simulating the average composition of a Champagne must was used. This medium contained phytosterol (mainly β-sitosterol) concentrations ranging from 0 to 8mg/L corresponding to turbidity between 10 and 90 NTU. Population reached during the stationary phase and the maximum fermentation rate are conditioned by the initial phytosterol concentration determining the amount of nitrogen consumption. An early loss of viability was observed when the lipid concentrations were very low. For example, the viability continuously decreased during the stationary phase to a final value of 50% for an initial phytosterol concentration of 1mg/L. In some fermentations, 10mg/L oxygen were added at the end of the growth phase to combine the effects of initial content of phytosterols in the musts and the de novo synthesis of ergosterol and unsaturated fatty acids induced by oxygen addition. Effect of oxygen supply on the fermentation kinetics was particularly significant for media with low phytosterol contents. For example, the maximum fermentation rate was increased by 1.4-fold and the fermentation time was 70h shorter with oxygen addition in the medium containing 2mg/L of phytosterols. As a consequence of the oxygen supply, for the media containing 3, 5 and 8mg/L of

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....

Optimization and control of a continuous stirred tank fermenter using learning system

Energy Technology Data Exchange (ETDEWEB)

Thibault, J [Dept. of Chemical Engineering, Laval Univ., Quebec City, PQ (Canada); Najim, K [CNRS, URA 192, GRECO SARTA, Ecole Nationale Superieure d' Ingenieurs de Genie Chimique, 31 - Toulouse (France)

1993-05-01

A variable structure learning automaton is used as an optimization and control of a continuous stirred tank fermenter. The alogrithm requires no modelling of the process. The use of appropriate learning rules enables to locate the optimum dilution rate in order to maximize an objective cost function. It is shown that a hierarchical structure of automata can adapt to environmental changes and can also modify efficiently the domain of variation of the control variable in order to encompass the optimum value. (orig.)

RESEARCHES CONCERNING THE EVOLUTION OF WINE MICROBIOTA DURING THE SPONTANEOUS FERMENTATION OF RED GRAPES JUICES

Directory of Open Access Journals (Sweden)

Ionica Deliu

2010-01-01

Full Text Available In order to keep its place on the wine international market, Romania should produce typical wines starting from localgrape varieties and conducting the alcoholic fermentation by starter cultures obtained from local isolated wine yeast.The present study was initiated due to the fact that there are few informations regarding the evolution of winemicrorganisms in plantations and in the fermentations process for quantitative point of view.The population dynamics of microbiota in Valea Calugareasca vineyard was analysed during the alcoholicfermentation. No yeast starter cultures had been used in order to investigate the dynamics of grape-related indigenousmicroorganisms population. Classical works and methods for alcoholic fermentation monitoring have been employed atthis level.At the beginning of fermentation the total number of yeasts found is doubling, while the number of bacteria is stabilizedat a value of 103 CFU/ml. During the alcoholic fermentation the yeasts become predominant (107–108 cfu/ml andcontinue the fermentation until its completion. Significant differences regarding the evolution of yeast microbiota forquantitative point of view between varieties have been recorded.

The element technology of clean fuel alcohol plant construction

Energy Technology Data Exchange (ETDEWEB)

Lee, D S; Lee, D S [Sam-Sung Engineering Technical Institute (Korea, Republic of); Choi, C Y [Seoul National University, Seoul (Korea, Republic of); and others

1996-02-01

The fuel alcohol has been highlighted as a clean energy among new renewable energy sources. However, the production of the fuel alcohol has following problems; (i)bulk distillate remains is generated and (ii) benzene to be used as a entertainer in the azeotropic distillation causes the environmental problem. Thus, we started this research on the ground of preserving the cleanness in the production of fuel alcohol, a clean energy. We examined the schemes of replacing the azotropic distillation column which causes the problems with MSDP(Molecular Sieve Dehydration Process) system using adsorption technology and of treating the bulk distillate remains to be generated as by-products. In addition, we need to develop the continuous yea station technology for the continuous operation of fuel alcohol plant as a side goal. Thus, we try to develop a continuous ethanol fermentation process by high-density cell culture from tapioca, a industrial substrate, using cohesive yeast. For this purpose, we intend to examine the problem of tapioca, a industrial substrate, where a solid is existed and develop a new process which can solve the problem. Ultimately, the object of this project is to develop each element technology for the construction of fuel alcohol plant and obtain the ability to design the whole plant. (author) 54 refs., 143 figs., 34 tabs.

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. © 2013 Institute of Food Technologists®

Potassium metabisulphite as a potential biocide against Dekkera bruxellensis in fuel ethanol fermentations.

Science.gov (United States)

Bassi, A P G; Paraluppi, A L; Reis, V R; Ceccato-Antonini, S R

2015-03-01

Dekkera bruxellensis is an important contaminant yeast of fuel ethanol fermentations in Brazil, whose system applies cell repitching between the fermentative cycles. This work evaluated the addition of potassium metabisulphite (PMB) on yeast growth and fermentative yields in pure and co-cultures of Saccharomyces cerevisiae and D. bruxellensis in two situations: addition to the acidic solution in which the cells are treated between the fermentative cycles or to the fermentation medium. In the range of 200-400 mg l(-1) , PMB was effective to control the growth of D. bruxellensis depending on the culture medium and strain. When added to the acidic solution (250 mg l(-1) ), a significant effect was observed in mixed cultures, because the inactivation of SO2 by S. cerevisiae most likely protected D. bruxellensis from being damaged by PMB. The physiological response of S. cerevisiae to the presence of PMB may explain the significant decrease in alcohol production. When added to the fermentation medium, PMB resulted in the control but not the death of D. bruxellensis, with less intensive effect on the fermentative efficiency. In co-culture with the addition of PMB, the fermentative efficiency was significantly lower than in the absence of PMB. This study is the first to evaluate the action of potassium metabisulphite to control the growth of Dekkera bruxellensis in the fermentation process for fuel alcohol production. As near as possible of industrial conditions, the study simulates the addition of that substance in different points in the fermentation process, verifying in which situation the effects over the starter yeast and alcohol yield are minimal and over D. bruxellensis are maximal. Co-culture fermentations were carried out in cell-recycled batch system. The feasibility of using this substance for this specific fermentation is discussed in light of the possible biological and chemical interactions. © 2014 The Society for Applied Microbiology.

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. Copyright © 2015 Elsevier B.V. All rights reserved.

EFFECT OF TEMPERATURE ON THE PROCESS OF BEER PRIMARY FERMENTATION

OpenAIRE

Miriam Solgajová; Helena Frančáková; Štefan Dráb; Žigmund Tóth

2013-01-01

Beer is a very popular and widespread drink worldwide. Beer may be defined as a foamy alcoholic drink aerated by carbon dioxide that is formed during fermentation. Sensorial and analytical character of beer is mainly formed during process of primary fermentation. Our work has monitored the influence of temperature of fermentation substrate on the process of primary fermentation during beer production. Obtained values of temperature and apparent extract out of four brews of 10% light hopped wo...

Cashew wine vinegar production: alcoholic and acetic fermentation

OpenAIRE

Silva, M. E.; Torres Neto, A. B.; Silva, W. B.; Silva, F. L. H.; Swarnakar, R.

2007-01-01

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 v...

The effect of lactic acid bacteria on cocoa bean fermentation.

Science.gov (United States)

Ho, Van Thi Thuy; Zhao, Jian; Fleet, Graham

2015-07-16

Cocoa beans (Theobroma cacao L.) are the raw material for chocolate production. Fermentation of cocoa pulp by microorganisms is crucial for developing chocolate flavor precursors. Yeasts conduct an alcoholic fermentation within the bean pulp that is essential for the production of good quality beans, giving typical chocolate characters. However, the roles of bacteria such as lactic acid bacteria and acetic acid bacteria in contributing to the quality of cocoa bean and chocolate are not fully understood. Using controlled laboratory fermentations, this study investigated the contribution of lactic acid bacteria to cocoa bean fermentation. Cocoa beans were fermented under conditions where the growth of lactic acid bacteria was restricted by the use of nisin and lysozyme. The resultant microbial ecology, chemistry and chocolate quality of beans from these fermentations were compared with those of indigenous (control) fermentations. The yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii, Kluyveromyces marxianus and Saccharomyces cerevisiae, the lactic acid bacteria Lactobacillus plantarum, Lactobacillus pentosus and Lactobacillus fermentum and the acetic acid bacteria Acetobacter pasteurianus and Gluconobacter frateurii were the major species found in control fermentations. In fermentations with the presence of nisin and lysozyme, the same species of yeasts and acetic acid bacteria grew but the growth of lactic acid bacteria was prevented or restricted. These beans underwent characteristic alcoholic fermentation where the utilization of sugars and the production of ethanol, organic acids and volatile compounds in the bean pulp and nibs were similar for beans fermented in the presence of lactic acid bacteria. Lactic acid was produced during both fermentations but more so when lactic acid bacteria grew. Beans fermented in the presence or absence of lactic acid bacteria were fully fermented, had similar shell weights and gave acceptable chocolates with no differences

Antibacterial profile of fermented seed extracts of ricinus communis ...

African Journals Online (AJOL)

The study was carried out to ascertain the antibacterial properties inherent in fermented seed extracts of Ricinus communis. Dry seeds of R. communis (Castor oil plant) were deshelled, grounded to powder, fermented, and then extracted both with alcohol and water using Soxhlet machine. Different concentrations of the ...

Rich nutrition from the poorest - cereal fermentations in Africa and Asia.

Science.gov (United States)

Nout, M J Rob

2009-10-01

Cereal fermentations in Africa and Asia involve mainly the processing of maize, rice, sorghum and the millets. Lactic acid bacteria (Lactobacillus, Pediococcus), Enterobacter spp., yeasts (Candida, Debaryomyces, Endomycopsis, Hansenula, Pichia, Saccharomyces and Trichosporon spp.) and filamentous fungi (Amylomyces, Aspergillus, Mucor, and Rhizopus spp.) contribute to desirable modifications of taste, flavour, acidity, digestibility, and texture in non-alcoholic beverages (e.g., uji, and ben-saalga), porridges (e.g., mawè) and cooked gels (e.g., kenkey, idli, and mifen). In addition, alcoholic beverages (beers such as tchoukoutou and jnard; and spirits e.g. jiu) are obtained using malt, or using amylolytic mixed microbial starter cultures as generators of fermentable substrates. Wet processing, marketing of multi-purpose intermediate products, co-fermentation for texture and nutrition, and mixed culture fermentations as practiced in indigenous fermentation processes are of interest for industrial innovation and for better control of natural mixed culture fermentation systems. On the other hand, the nutritional properties of traditional cereal fermented products can be enhanced by increasing their nutrient and energy density, as well as by increasing their mineral status by combining mineral fortification and dephytinization.

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...

Comparing a Dynamic Fed-Batch and a Continuous Steady-State Simulation of Ethanol Fermentation in a Distillery to a Stoichiometric Conversion Simulation

OpenAIRE

Fonseca, G.C.; Costa, C.B.B.; Cruz, A.J.G.

2017-01-01

Abstract An autonomous sugarcane bioethanol plant was simulated in EMSO software, an equation oriented process simulator. Three types of fermentation units were simulated: a six parallel fed-batch reactor system, a set of four CSTR in steady state and one consisting of a single stoichiometric reactor. Stoichiometric models are less accurate than kinetic-based fermentation models used for fed-batch and continuous fermenter simulations, since they do not account for inhibition effects and depen...

A modified indirect mathematical model for evaluation of ethanol production efficiency in industrial-scale continuous fermentation processes.

Science.gov (United States)

Canseco Grellet, M A; Castagnaro, A; Dantur, K I; De Boeck, G; Ahmed, P M; Cárdenas, G J; Welin, B; Ruiz, R M

2016-10-01

To calculate fermentation efficiency in a continuous ethanol production process, we aimed to develop a robust mathematical method based on the analysis of metabolic by-product formation. This method is in contrast to the traditional way of calculating ethanol fermentation efficiency, where the ratio between the ethanol produced and the sugar consumed is expressed as a percentage of the theoretical conversion yield. Comparison between the two methods, at industrial scale and in sensitivity studies, showed that the indirect method was more robust and gave slightly higher fermentation efficiency values, although fermentation efficiency of the industrial process was found to be low (~75%). The traditional calculation method is simpler than the indirect method as it only requires a few chemical determinations in samples collected. However, a minor error in any measured parameter will have an important impact on the calculated efficiency. In contrast, the indirect method of calculation requires a greater number of determinations but is much more robust since an error in any parameter will only have a minor effect on the fermentation efficiency value. The application of the indirect calculation methodology in order to evaluate the real situation of the process and to reach an optimum fermentation yield for an industrial-scale ethanol production is recommended. Once a high fermentation yield has been reached the traditional method should be used to maintain the control of the process. Upon detection of lower yields in an optimized process the indirect method should be employed as it permits a more accurate diagnosis of causes of yield losses in order to correct the problem rapidly. The low fermentation efficiency obtained in this study shows an urgent need for industrial process optimization where the indirect calculation methodology will be an important tool to determine process losses. © 2016 The Society for Applied Microbiology.

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.)

Occurrence and function of yeasts in Asian indigenous fermented foods

NARCIS (Netherlands)

Aidoo, K.E.; Nout, M.J.R.; Sarkar, P.K.

2006-01-01

In the Asian region, indigenous fermented foods are important in daily life. In many of these foods, yeasts are predominant and functional during the fermentation. The diversity of foods in which yeasts predominate ranges from leavened bread-like products such as nan and idli, to alcoholic beverages

Carbon 14 and tritium radioactivity of alcohols

International Nuclear Information System (INIS)

Guerain, J.; Tourliere, S.

1975-01-01

The method of measuring carbon 14 radioactivity of alcohols has been perfected in order to establish the correct determination of synthetic alcohol added to fermentation alcohol. The specific carbon and tritium activity of alcohol of different origins have been determined for 1973 and 1974. The Suess effect and nuclear fall-out are observed [fr

Technical development of alcohol for fuel. Inspection and breeding of superior bacteria

Energy Technology Data Exchange (ETDEWEB)

1987-09-01

Heat- and alcohol-resistant bacteria for alcoholic fermentation were separated from the soils in Japan and abroad and the performance was evaluated to develop superior bacteria for ethanol fermentation. The superior bacteria pertinent to alcoholic fermentation were bred by domestication, variation treatment, cell fusion and gene manipulation. The productivity of ethanol was increased by controlling pH of thermophilic, aerobic cellulase and culturing the mixture of added nutrients. CMC ase and Beta-glucosidase genes, the component enzymes of cellulase, were successfully developed by Zymomonas sp. A promotor selecting vector of Zymomonas was produced for developing xylolase gene to acquire an active promotor.

Mystery behind Chinese liquor fermentation

NARCIS (Netherlands)

Jin, Guangyuan; Zhu, Yang; Xu, Yan

2017-01-01

Background Chinese liquor, a very popular fermented alcoholic beverage with thousands of years’ history in China, though its flavour formation and microbial process have only been partly explored, is facing the industrial challenge of modernisation and standardisation for food quality and safety as

Metabolite profiling of the fermentation process of "yamahai-ginjo-shikomi" Japanese sake

OpenAIRE

Tatsukami, Yohei; Morisaka, Hironobu; Aburaya, Shunsuke; Aoki, Wataru; Kohsaka, Chihiro; Tani, Masafumi; Hirooka, Kiyoo; Yamamoto, Yoshihiro; Kitaoka, Atsushi; Fujiwara, Hisashi; Wakai, Yoshinori; Ueda, Mitsuyoshi

2018-01-01

Sake is a traditional Japanese alcoholic beverage prepared by multiple parallel fermentation of rice. The fermentation process of “yamahai-ginjo-shikomi” sake is mainly performed by three microbes, Aspergillus oryzae, Saccharomyces cerevisiae, and Lactobacilli; the levels of various metabolites fluctuate during the fermentation of sake. For evaluation of the fermentation process, we monitored the concentration of moderate-sized molecules (m/z: 200–1000) dynamically changed during the fermenta...

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. © 2015 American Institute of Chemical Engineers.

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

Science.gov (United States)

2011-01-01

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

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.

Estudo da fermentação alcoólica de soluções diluídas de diferentes açucares utilizando microcalorimetria de fluxo Study of the alcoholic fermentation of sugars diluted solutions through flow microcalorimetry

Directory of Open Access Journals (Sweden)

Pedro L. O. Volpe

1997-10-01

Full Text Available The present study shows that with liquid nitrogen stored inocula of Saccharomyces cerevisiae, and standardized experimental procedure, flow microcalorimetry can be a valuable tool for monitoring in real time the alcoholic fermentation processes on line. The avaliation of cultural conditions contained different carbon sources for alcohol fermentation (sucrose, glucose, fructose, manose, maltose, galactose, molasses, honey and sugar cane and their effects on the heat output recording is discussed. Some examples of diauxic growth is given, where the microcalorimeters serves to detect the temporal order of succession of alternating metabolic pathways.

Alcohol Intolerance

Science.gov (United States)

... ingredients commonly found in alcoholic beverages, especially in beer or wine, can cause intolerance reactions. These include: Sulfites or other preservatives Chemicals, grains or other ingredients Histamine, a byproduct of fermentation or brewing In some cases, reactions can be ...

An improved simplified model predictive control algorithm and its application to a continuous fermenter

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W. H. Kwong

2000-06-01

Full Text Available The development of a new simplified model predictive control algorithm has been proposed in this work. The algorithm is developed within the framework of internal model control, and it is easy to understanding and implement. Simulation results for a continuous fermenter, which show that the proposed control algorithm is robust for moderate variations in plant parameters, are presented. The algorithm shows a good performance for setpoint tracking.

Microbiological Research on the Traditional Alcoholic Fermented Milk“Airag”in Mongolia

OpenAIRE

宮本, 拓

2015-01-01

　Airag, a traditional fermented milk well loved by Mongolians, has been drunk habitually sinceancient times as a unique drink. It is produced from cow, mare and camel milk by a traditional method using indigenous starter cultures containing lactic acid bacteria, yeasts and other fermentative microorganisms. Spontaneously fermented milk products have for centuries been consumed for their therapeutic value in promoting health and well-being, especially among the pastoral communities in Mongolia...

Heat-stable, FE-dependent alcohol dehydrogenase for aldehyde detoxification

Science.gov (United States)

Elkins, James G.; Clarkson, Sonya

2018-04-24

The present invention relates to microorganisms and polypeptides for detoxifying aldehydes associated with industrial fermentations. In particular, a heat-stable, NADPH- and iron-dependent alcohol dehydrogenase was cloned from Thermoanaerobacter pseudethanolicus 39E and displayed activity against a number of aldehydes including inhibitory compounds that are produced during the dilute-acid pretreatment process of lignocellulosic biomass before fermentation to biofuels. Methods to use the microorganisms and polypeptides of the invention for improved conversion of bio mass to biofuel are provided as well as use of the enzyme in metabolic engineering strategies for producing longer-chain alcohols from sugars using thermophilic, fermentative microorganisms.

Continuous measurement of ethanol production by aerobic yeast suspensions with an enzyme electrode

Energy Technology Data Exchange (ETDEWEB)

Verduyn, C.; Zomerdijk, T.P.L.; Dijken, J.P. van; Scheffers, W.A.

1984-03-01

An alcohol electrode was constructed which consisted of an oxygen probe onto which alcohol oxidase was immobilized. This enzyme electrode was used, in combination with a reference oxygen electrode, to study the short-term kinetics of alcoholic fermentation by aerobic yeast suspensions after pulsing with glucose. The results demonstrate that this device is an excellent tool in obtaining quantitative data on the short-term expression of the Crabtree effect in yeasts. Samples from aerobic glucose-limited chemostat cultures of Saccharomyces cerevisiae not producing ethanol, immediately (within 2 min) exhibited aerobic alcohol fermentation after being pulsed with excess glucose. With chemostat-grown Candida utilis, however, ethanol production was not detactable even at high sugar concentrations. The Crabtree effect in S. cerevisiae was studied in more detail with commercial baker's yeast. Ethanol formation occurred only at initial glucose concentrations exceeding 150 mgx1/sup -1/, and the rate of alcoholic fermentation increased with increasing glucose concentrations up to 1,000 mgx1/sup -1/ glucose. Similar experiments with batch cultures of certain ''non-fermentative'' yeasts revealed that these organisms are capable of alcoholic fermentation. Thus, even under fully aerobic conditions, Hansenula nonfermentans and Candida buffonii produced ethanol after being pulsed with glucose. In C. buffonii ethanol formation was already apparent at very low glucose concentrations (10 mgx1/sup -1/) and alcoholic fermentation even proceeded at a higher rate than in S. cerevisiae. With Rhodotorula rubra, however, the rate of ethanol formation was below the detection limit, i.e., less than 0.1 mmolxg cells/sup -1/xh/sup -1/.

Alcohol or feed product from rotten sweet potatoes

Energy Technology Data Exchange (ETDEWEB)

Ikeda, T

1956-06-25

Rotten sweet potatoes were mixed with the same weight of a pressed cake of fermented alcohol mash, and the mixture was cooked and fermented with amylo stock mash under semisolid conditions for five days. The fermented mash was steam-distilled to recover ethanol, and a solid residue was dried to give a nutrient feed product.

Development of a distilled-like alcoholic drink from blueberry (Vaccinium corymbosum cv. Brigitta, and sensory analysis

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Nelson Eduardo Loyola López

2016-01-01

Full Text Available The present study aimed to develop a distilled-like alcoholic beverage using blueberry from the Brigitta cultivar, either juice, skin or the mixture of both components according to the Law of alcohols Nº 18.455 from Chile, testing the alcoholic grade and sensory attributes such as; flavour, color, aroma and acceptability. The development consisted of two parts. Firstly, an alcoholic fermentation, and secondly, the distillation of the beverage. Before bottling and labelling, the final product was filtrated. Determinations such as; alcoholic fermentation, temperature, density and soluble solids were performed. Resulting values were subjected to analysis of variance and multiple comparison Tukey tests. It is feasible to obtain a dis-tilled alcoholic beverage from frozen blueberries. Sensory attributes better identified for T1: Blueberry juice fermentation, by panelists, were flavour and color. However, liquors from the treatment T3: fermentation blueberry skin, were identified by panelists as having a better aroma.

Mucoraceous moulds involved in the commercial fermentation of Sufu Pehtze

NARCIS (Netherlands)

Han, B.; Kuijpers, F.A.; Thanh, N.V.; Nout, M.J.R.

2004-01-01

Sufu is a fermented cheese-like soybean product in China and Vietnam, obtained by fungal solid-state fermentation of soybean curd (tofu), which results in moulded tofu or 'pehtze'. The final product sufu is obtained by maturing pehtze in a brine containing alcohol and salt during a period of several

Influence of Temperature and Carbon Dioxide on Fermentation of Cabernet Sauvignon Must

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Jan Mavri

2003-01-01

Full Text Available In the process of wine fermentation temperature and the amount of carbon dioxide present represent parameters that can be easily monitored and controlled. The influence of variation of the process temperature and the fluxes of additional inlet gaseous carbon dioxide in Saccharomyces bayanus fermentation of Cabernet Sauvignon grape must on the accumulation of biomass and production of metabolites was studied. All experiments with temperature and redox potential control on-line were performed in a 10-litre laboratory stirred tank reactor. Metabolites of Saccharomyces bayanus fermentation comprising higher alcohols (1-propanol, 2-butanol, isoamyl alcohol, as well as reducing sugars, were measured off-line by gas and high pressure liquid chromatography.

Improved glycerol production from cane molasses by the sulfite process with vacuum or continuous carbon dioxide sparging during fermentation

Energy Technology Data Exchange (ETDEWEB)

Kalle, G.P.; Naik, S.C.; Lashkari, B.Z.

1985-01-01

The conventional sulfite process for glycerol production from molasses using Saccharomyces cerevisiae var. Hansen was modified to obtain product concentrations of up to 230 g/l and productivity of 15 g/l.d by fermenting under vacuum (80 mm) or with continuous sparging of CO2 (0.4 vvm). Under these conditions the requirement of sulfite for optimum production of glycerol was reduced by two thirds (20 g/l), the ethanol concentration in the medium was kept below 30 g/l and the competence of yeast cells to ferment was conserved throughout the fermentation period for up to 20 days. In addition to the above, the rate of incorporation of sulfite had a significant effect on glucose fermentation and glycerol yields. There was an optimal relationship between glycerol yields and the molar ratio of sulfite to glucose consumed, which for cane molasses was 0.67. This ratio was characteristic of the medium composition.

Improved glycerol production from cane molasses by the sulfite process with vacuum or continuous carbon dioxide sparging during fermentation

Energy Technology Data Exchange (ETDEWEB)

Kalle, G.P.; Naik, S.C.; Lashkari, B.Z.

1985-01-01

The conventional sulfite process for glycerol production from molasses using Saccharomyces cerevisiae var. Hansen was modified to obtain product concentrations of up to 230 g/l and productivity of 15 g/l x d by fermenting under vacuum (80 mm) or with continuous sparging of CO/sub 2/ (0.4 vvm). Under these conditions the requirement of sulfite for optimum production of glycerol was reduced by two thirds (20 g/l), the ethanol concentration in the medium was kept below 30 g/l and the competence of yeast cells to ferment was conserved throughout the fermentation period for up to 20 days. In addition to the above, the rate of incorporation of sulfite had a significant effect on glucose fermentation and glycerol yields. There was an optimal relationship between glycerol yields and the molar ratio of sulfite to glucose consumed, which for cane molasses was 0.67. This ratio was characteristic of the medium composition. 10 references, 4 figures, 3 tables.

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

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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.

Novel Method of Lactic Acid Production by Electrodialysis Fermentation

OpenAIRE

Hongo, Motoyoshi; Nomura, Yoshiyuki; Iwahara, Masayoshi

1986-01-01

In lactic acid fermentation by Lactobacillus delbrueckii, the produced lactic acid affected the lactic acid productivity. Therefore, for the purpose of alleviating this inhibitory effect, an electrodialysis fermentation method which can continuously remove produced lactic acid from the fermentation broth was applied to this fermentation process. As a result, the continuation of fermentation activity was obtained, and the productivity was three times higher than in non-pH-controlled fermentati...

The effect of SO2 on the production of ethanol, acetaldehyde, organic acids, and flavor volatiles during industrial cider fermentation.

Science.gov (United States)

Herrero, Mónica; García, Luis A; Díaz, Mario

2003-05-21

SO(2) is widely used in cider fermentation but also in other alcoholic beverages such as wine. Although the authorized limit is 200 ppm total SO(2), the International Organizations recommend its total elimination or at least reduction due to health concerns. Addition of SO(2) to apple juice at levels frequently used in industrial cidermaking (100 mg/L) induced significantly higher acetaldehyde production by yeast than that obtained without SO(2). Although the practical implications of acetaldehyde evolution under cidermaking conditions has been overcome by research and few data are available, this compound reached levels in two 2000 L bioreactors that may have prevented the occurrence of simultaneous alcoholic and malolactic fermentation. It was observed that malolactic fermentation had a positive effect promoting reduction of acetaldehyde levels in cider fermented with juice, SO(2)-treated or not. The addition of SO(2) clearly delayed malolactic fermentation comparing to the control, affecting not the onset of the malolactic fermentation but the rate of malic acid degradation. This compound, however, had a stimulatory effect on alcoholic fermentation.

Dynamics and diversity of microbial community succession in traditional fermentation of Shanxi aged vinegar.

Science.gov (United States)

Nie, Zhiqiang; Zheng, Yu; Du, Hongfu; Xie, Sankuan; Wang, Min

2015-05-01

The traditional fermentation of Shanxi aged vinegar (SAV), a well-known traditional Chinese vinegar, generally involves the preparation of starter daqu, starch saccharification, alcoholic fermentation (AF) and acetic acid fermentation (AAF). Dynamics and diversity of microbial community succession in daqu and other fermentation stages were investigated by denaturing gradient gel electrophoresis (DGGE). Results showed that eight bacterial genera and four fungal genera were found in daqu. However, Staphylococcus, Saccharopolyspora, Bacillus, Oceanobacillus, Enterobacter, Streptomyces, Eurotium, Monascus and Pichia in daqu were eradicated during AF. Four bacterial genera and three fungal genera were found in this stage. Weissella, Lactobacillus, Streptococcus, Saccharomyces, and Saccharomycopsis were the dominant microorganisms in the late stage of AF. During AAF, four bacterial genera and four fungal genera were found. Weissella, Streptococcus, Klebsiella, Escherichia, and Cladosporium gradually disappeared; the dominant microorganisms were Acetobacter, Lactobacillus, Saccharomycopsis, and Alternaria in the late stage of AAF. Alpha diversity metrics showed that fungal diversity in daqu was greater than that in AF and AAF. By contrast, bacterial diversity decreased from daqu to AF and increased in the first three days of AAF and then decreased. Hence, these results could help understand dynamics of microbial community succession in continuous fermentation of traditional Chinese vinegars. Copyright © 2014 Elsevier Ltd. All rights reserved.

Process engineering and scale-up of autotrophic Clostridium strain P11 syngas fermentation

Science.gov (United States)

Kundiyana, Dimple Kumar Aiyanna

indicated that it is possible to modulate the product formation by limiting key nutrients of acetyl-CoA pathway and using a continuous fermentation in two-stage fermentor design to improve ethanol yields. The last experimental study was conducted to commission a pilot scale fermentor, and subsequently scale-up the Clostridium strain P11 fermentation from a bench-scale to a pilot scale 100-L fermentor. Results indicated a six-fold improvement in ethanol concentration (25.3 g L-1 at the end of 59 d) compared to previous Clostridium strain P11 and Clostridium carboxidivorans fermentations plus the formation of other compounds such as isopropyl alcohol, acetic acid and butanol, which are of commercial importance.

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. © 2011 Institute of Food Technologists®

Antagonism Between Osmophilic Lactic Acid Bacteria and Yeasts in Brine Fermentation of Soy Sauce

OpenAIRE

Noda, Fumio; Hayashi, Kazuya; Mizunuma, Takeji

1980-01-01

Brine fermentation by osmophilic lactic acid bacteria and yeasts for long periods of time is essential to produce a good quality of shoyu (Japanese fermented soy sauce). It is well known that lactic acid fermentation by osmophilic lactic acid bacteria results in the depression of alcoholic fermentation by osmophilic yeasts, but the nature of the interaction between osmophilic lactic acid bacteria and yeasts in brine fermentation of shoyu has not been revealed. The inhibitory effect of osmophi...

Continuous fed-batch vacuum fermentation system for glycerol from molasses by the sulfite process

Energy Technology Data Exchange (ETDEWEB)

Kalle, G.P.; Naik, S.C.

1985-01-01

A continuous fed-batch vacuum fermentation system has been described for the production of glycerol from cane molasses (and juice) by a conventional sulfite process. A glycerol concentration of 80 g/l was achieved with a productivity of 30 g/l/day at a dilution rate of 0.4/day which is twice that from a vacuum batch process (15 g/l/day) or four times that obtained without vacuum (8 g/l/day). 8 references.

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. Copyright © 2016. Published by Elsevier Ltd.

Single-cell analysis of S. cerevisiae growth recovery after a sublethal heat-stress applied during an alcoholic fermentation.

Science.gov (United States)

Tibayrenc, Pierre; Preziosi-Belloy, Laurence; Ghommidh, Charles

2011-06-01

Interest in bioethanol production has experienced a resurgence in the last few years. Poor temperature control in industrial fermentation tanks exposes the yeast cells used for this production to intermittent heat stress which impairs fermentation efficiency. Therefore, there is a need for yeast strains with improved tolerance, able to recover from such temperature variations. Accordingly, this paper reports the development of methods for the characterization of Saccharomyces cerevisiae growth recovery after a sublethal heat stress. Single-cell measurements were carried out in order to detect cell-to-cell variability. Alcoholic batch fermentations were performed on a defined medium in a 2 l instrumented bioreactor. A rapid temperature shift from 33 to 43 °C was applied when ethanol concentration reached 50 g l⁻¹. Samples were collected at different times after the temperature shift. Single cell growth capability, lag-time and initial growth rate were determined by monitoring the growth of a statistically significant number of cells after agar medium plating. The rapid temperature shift resulted in an immediate arrest of growth and triggered a progressive loss of cultivability from 100 to 0.0001% within 8 h. Heat-injured cells were able to recover their growth capability on agar medium after a lag phase. Lag-time was longer and more widely distributed as the time of heat exposure increased. Thus, lag-time distribution gives an insight into strain sensitivity to heat-stress, and could be helpful for the selection of yeast strains of technological interest.

Carbery milk products in Ireland produces alcohol from whey

Energy Technology Data Exchange (ETDEWEB)

Hansen, R

1980-01-01

A brief illustrated description is given of alcohol production by Carbery Milk Products Ltd., introduced in 1976 as an alternative to whey drying. The initial investment into the new alcohol factory was 1.6 million. The process includes whey ultrafiltration at a rate of 125,000 gallons/day, fermentation of the premeate in 6 fermentation tanks (total capacity 42,000 gallons) in batch operation, each requiring on average 6 hours; efficiency of lactose conversion to alcohol is 86% of the theoretical yield. After separation of the yeasts, the liquor is pasteurized and heated to the correct temperature for distillation which is carried out in a plant consisting of six 32-metre high cylinders incorporating rectification towers. The finished alcohol is stored under customs supervision in 3 storage tanks, each with a capacity of 125000 gallons. The waste products from the fermentation and distillation stages necessitated the installation of a purification plant for treating daily about 200000 gallons effluent with 9000 lb BOD, in addition to another plant handling 400 000 gallons with also 9000 lb BOD of normal dairy waste water.

Potential influence of compounds released in degradation of phytates on the course of alcoholic fermentation of high gravity mashes – simulation with analogs of these compounds

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Mikulski Dawid

2017-09-01

Full Text Available Aim of the study was to evaluate the effect of supplementation of high gravity media with mineral compounds and myo-inositol, at concentration which would be obtained as a result of degradation of phytates present in raw material during alcoholic fermentation. The process of alcoholic fermentation was conducted under laboratory conditions in a 72 h system at 37°C with the use of S. cerevisiae D-2 strain. Calcium chloride proved to be the most effective of all supplements tested. Final ethanol concentration increased by 1.2% v v−1 and the yield of process increased by ca. 7 dm−3 ethanol 100 kg−1 of starch in comparison with control. Selective supplementation with KH2PO4, ZnSO4 and MgSO4 also increased the ethanol concentration, but the effect was accompanied by a deterioration in composition of volatile products. The hydrolysis of phytate complexes with microbial phytases can be an alternative solution to supplementation of HG mashes presented in this work.

Influence of Fermentation Process on the Anthocyanin Composition of Wine and Vinegar Elaborated from Strawberry.

Science.gov (United States)

Hornedo-Ortega, Ruth; Álvarez-Fernández, M Antonia; Cerezo, Ana B; Garcia-Garcia, Isidoro; Troncoso, Ana M; Garcia-Parrilla, M Carmen

2017-02-01

Anthocyanins are the major polyphenolic compounds in strawberry fruit responsible for its color. Due to their sensitivity, they are affected by food processing techniques such as fermentation that alters both their chemical composition and organoleptic properties. This work aims to evaluate the impact of different fermentation processes on individual anthocyanins compounds in strawberry wine and vinegar by UHPLC-MS/MS Q Exactive analysis. Nineteen, 18, and 14 anthocyanin compounds were identified in the strawberry initial substrate, strawberry wine, and strawberry vinegar, respectively. Four and 8 anthocyanin compounds were tentatively identified with high accuracy for the 1st time to be present in the beverages obtained by alcoholic fermentation and acetic fermentation of strawberry, respectively. Both, the total and the individual anthocyanin concentrations were decreased by both fermentation processes, affecting the alcoholic fermentation to a lesser extent (19%) than the acetic fermentation (91%). Indeed, several changes in color parameters have been assessed. The color of the wine and the vinegar made from strawberry changed during the fermentation process, varying from red to orange color, this fact is directly correlated with the decrease of anthocyanins compounds. © 2017 Institute of Food Technologists®.

Performance evaluation of Pichia kluyveri, Kluyveromyces marxianus and Saccharomyces cerevisiae in industrial tequila fermentation.

Science.gov (United States)

Amaya-Delgado, L; Herrera-López, E J; Arrizon, Javier; Arellano-Plaza, M; Gschaedler, A

2013-05-01

Traditionally, industrial tequila production has used spontaneous fermentation or Saccharomyces cerevisiae yeast strains. Despite the potential of non-Saccharomyces strains for alcoholic fermentation, few studies have been performed at industrial level with these yeasts. Therefore, in this work, Agave tequilana juice was fermented at an industrial level using two non-Saccharomyces yeasts (Pichia kluyveri and Kluyveromyces marxianus) with fermentation efficiency higher than 85 %. Pichia kluyveri (GRO3) was more efficient for alcohol and ethyl lactate production than S. cerevisiae (AR5), while Kluyveromyces marxianus (GRO6) produced more isobutanol and ethyl-acetate than S. cerevisiae (AR5). The level of volatile compounds at the end of fermentation was compared with the tequila standard regulation. All volatile compounds were within the allowed range except for methanol, which was higher for S. cerevisiae (AR5) and K. marxianus (GRO6). The variations in methanol may have been caused by the Agave tequilana used for the tests, since this compound is not synthesized by these yeasts.

Determination of volatile components in fermented soybean prepared by a co-culture of Bacillus subtilis and Rhizopus oligosporus

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Chukeatirote, E.,

2017-07-01

Full Text Available Fermented soybeans are traditional foods widely consumed in many countries (i.e., Natto in Japan, Jang in Korea, Kinema in India, Douichi in China, and Thua Nao in Thailand. In this study, an attempt was made with an expectation to improve the fermentation process using a co-culture of Bacillus subtilis and Rhizopus oligosporus. Initially, the raw soybeans were washed, sterilized by autoclaving, and inoculated with two inocula; for this, three different ratios between B. subtilis and R. oligosporus used were 100:0, 50:50, and 0:100. The fermentation was then carried out at 30°C for 3 days. The volatile compounds in the non-fermented and the fermented soybean products were determined by gas chromatography/ mass spectrometry (GC/MS and extracted using a solid phase microextraction (SPME technique. In total, 165 compounds were identified in the non-fermented and the fermented soybean products. For the non-fermented products, the predominant volatile compounds were alcohols (25.81%, aldehydes (13.64%, acids and esters (7.57%, furans (6.13% and ketones (0.88%. In contrast, the major volatiles compounds presented in the fermented soybeans were as follows: i The treatment of 100:0 consisted of acids and esters (35.89%, alcohols (14.55%, aldehydes (8.72%, ketones (4.97%, pyrazines (4.87%, and furans (4.22%; ii 50:50 comprised of acids and esters (55.62%, alcohols (16.22%, aldehydes (7.80%, pyrazine (3.65%, ketones (2.55%, furans (1.67%, and aromatic compounds (1.46%; and iii 0:100 included acids and esters (66.50%, alcohols (15.44%, aldehydes (2.59%, ketones (2.72%, furans (1.89%, aromatic compounds (1.80%, pyrazines (1.35%, and sulphur containing compounds (0.24% respectively.

Uniqueness of Ethiopian traditional alcoholic beverage of plant origin, tella

Directory of Open Access Journals (Sweden)

Mooha Lee

2015-09-01

Full Text Available There are many kinds of traditional fermented beverages in Ethiopia, not only of animal origin, but also of plant origin. In everyday life people enjoy fermented beverages and particularly when having guests, they like to treat them to traditional alcoholic beverages. Tella, tej, areki, borde, and shamita are drinks that each household brews to treat guests. Substrates for their production are from locally available raw materials. Therefore, the basic production method is the same, but the tastes may vary. One of the most consumed fermented alcoholic beverages is tella, which is made mostly with barley but wheat, maize, sorghum, and teff are utilized depending on the region. Its production process shows the similarity to beer: addition of malt and gesho which has the same function as hops in beer. The main fermentation yeast is Saccharomyces cerevisiae and saccharification of cereal starch seems to depend on malt. However, the degree of alcoholic fermentation is low and alcohol content varies between 2 and 6%. Lactic acid bacteria are very active in tella so pH ranges 4–5 give typical tastes such as sourness, sweetness, and bitterness. As the Ethiopian economy improves, more people drink western style beers. Tella has not been commercialized yet, so the process has not been standardized and modernized. Considering the case of Korean makgeolli and the Ethiopian creativity of utilizing gesho in tella, Ethiopia should pay more attention to tella for globalization.

Zeolitic catalytic conversion of alcohols to hydrocarbons

Science.gov (United States)

Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

2018-04-10

A method for converting an alcohol to a hydrocarbon, the method comprising contacting said alcohol with a metal-loaded zeolite catalyst at a temperature of at least 100.degree. C. and up to 550.degree. C., wherein said alcohol can be produced by a fermentation process, said metal is a positively-charged metal ion, and said metal-loaded zeolite catalyst is catalytically active for converting said alcohol to said hydrocarbon.

Physico-chemical and microbiological characterization of spontaneous fermentation of Cellina di Nardò and Leccino table olives

Directory of Open Access Journals (Sweden)

Gianluca eBleve

2014-10-01

Full Text Available Table olives are one of the most important traditional fermented vegetables in Europe and their world consumption is constantly increasing. In the Greek style, table olives are obtained by spontaneous fermentations, without any chemical debittering treatment. Evolution of sugars, organic acids, alcohols, mono and polyphenol compounds and volatile compounds associated with the fermentative metabolism of yeasts and bacteria throughout the natural fermentation process of the two Italian olive cultivars Cellina di Nardò and Leccino were determined. A protocol was developed and applied aimed at the technological characterization of LAB and yeast strains as possible candidate autochthonous starters for table olive fermentation from Cellina di Nardò and Leccino cultivars. The study of the main physic-chemical parameters and volatile compounds during fermentation helped to determine chemical descriptors that may be suitable for monitoring olive fermentation. In both the analyzed table olive cultivars, aldehydes proved to be closely related to the first stage of fermentation (30 days, while higher alcohols (2-methyl-1-propanol; 3-methyl-1-butanol, styrene, and o-cymene were associated with the middle stage of fermentation (90 days and acetate esters with the final step of olive fermentation (180 days.

RNAseq-based transcriptome comparison of Saccharomyces cerevisiae strains isolated from diverse fermentative environments.

Science.gov (United States)

Ibáñez, Clara; Pérez-Torrado, Roberto; Morard, Miguel; Toft, Christina; Barrio, Eladio; Querol, Amparo

2017-09-18

Transcriptome analyses play a central role in unraveling the complexity of gene expression regulation in Saccharomyces cerevisiae. This species, one of the most important microorganisms for humans given its industrial applications, shows an astonishing degree of genetic and phenotypic variability among different strains adapted to specific environments. In order to gain novel insights into the Saccharomyces cerevisiae biology of strains adapted to different fermentative environments, we analyzed the whole transcriptome of three strains isolated from wine, flor wine or mezcal fermentations. An RNA-seq transcriptome comparison of the different yeasts in the samples obtained during synthetic must fermentation highlighted the differences observed in the genes that encode mannoproteins, and in those involved in aroma, sugar transport, glycerol and alcohol metabolism, which are important under alcoholic fermentation conditions. These differences were also observed in the physiology of the strains after mannoprotein and aroma determinations. This study offers an essential foundation for understanding how gene expression variations contribute to the fermentation differences of the strains adapted to unequal fermentative environments. Such knowledge is crucial to make improvements in fermentation processes and to define targets for the genetic improvement or selection of wine yeasts. Copyright © 2017 Elsevier B.V. All rights reserved.

Ethanol production by repeated batch and continuous fermentations of blackstrap molasses using immobilized yeast cells on thin-shell silk cocoons

International Nuclear Information System (INIS)

Rattanapan, Anuchit; Limtong, Savitree; Phisalaphong, Muenduen

2011-01-01

Highlights: → Thin-shell silk cocoons for immobilization of Saccharomycescerevisiae. → Advantages: high mechanical strength, light weight, biocompatibility and high surface area. → Enhanced cell stability and ethanol productivity by the immobilization system. -- Abstract: A thin-shell silk cocoon (TSC), a residual from the silk industry, is used as a support material for the immobilization of Saccharomyces cerevisiae M30 in ethanol fermentation because of its properties such as high mechanical strength, light weight, biocompatibility and high surface area. In batch fermentation with blackstrap molasses as the main fermentation substrate, an optimal ethanol concentration of 98.6 g/L was obtained using a TSC-immobilized cell system at an initial reducing sugar concentration of 240 g/L. The ethanol concentration produced by the immobilized cells was 11.5% higher than that produced by the free cells. Ethanol production in five-cycle repeated batch fermentation demonstrated the enhanced stability of the immobilized yeast cells. Under continuous fermentation in a packed-bed reactor, a maximum ethanol productivity of 19.0 g/(L h) with an ethanol concentration of 52.8 g/L was observed at a 0.36 h -1 dilution rate.

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Torulaspora delbrueckii contribution in mixed brewing fermentations with different Saccharomyces cerevisiae strains.

Science.gov (United States)

Canonico, Laura; Comitini, Francesca; Ciani, Maurizio

2017-10-16

In recent years, there has been growing demand for distinctive high quality beer. Fermentation management has a fundamental role in beer quality and the levels of aroma compounds. Use of non-conventional yeast has been proposed to enhance beer bioflavor. In the present work we investigated mixed fermentations using three commercial Saccharomyces cerevisiae strains, without and with addition of a selected Torulaspora delbrueckii strain evaluating their interactions, as well as the aroma profiles. At the S. cerevisiae/T. delbrueckii co-inoculation ratio of 1:20, viable cell counts indicated that T. delbrueckii dominated all of the three combinations. In the mixed fermentations, T. delbrueckii provided higher levels of higher alcohols (excepting of β-phenyl ethanol), in contrast to data obtained in winemaking, where higher alcohols had lower levels. Moreover, mixed fermentations showed significantly higher ethyl acetate (from 5 to 16mg/L) and isoamyl acetate (from 0.019 to 0.128mg/L), and were generally lower in ethyl hexanoate and ethyl octanoate. Therefore, irrespective of S. cerevisiae strain, T. delbrueckii influenced on all mixed fermentations. On the other hand, the mixed fermentations were also affected by each of the three S. cerevisiae strains, which resulted in beers with distinctive flavors. Copyright © 2017 Elsevier B.V. All rights reserved.

Designer Yeasts for the Fermentation Industry of the 21st Century

Directory of Open Access Journals (Sweden)

Isak S. Pretorius

2003-01-01

Full Text Available The budding yeast, Saccharomyces cerevisiae, has enjoyed a long and distinguished history in the fermention industry. Owing to its efficiency in producing alcohol, S. cerevisiae is, without doubt, the most important commercial microorganism with GRAS (Generally Regarded As Safe status. By brewing beer and sparkling wine, mankind’s oldest domesticated organism made possible the world’s first biotechnological processes. With the emergence of modern molecular genetics, S. cerevisiae has again been harnessed to shift the frontiers of mankind’s newest revolution, genetic engineering. S. cerevisiae is at the forefront of many of these developments in modern biotechnology. Consequently, the industrial importance of S. cerevisiae has extended beyond traditional fermentation. Today, the products of yeast biotechnologies impinge on many commercially important sectors, including food, beverages, biofuels, chemicals, industrial enzymes, pharmaceuticals, agriculture and the environment. Nevertheless, since ethyl alcohol produced by yeast fermentation is likely to remain the foremost worldwide biotechnological commodity for the foreseeable future, this review focuses on advances made with respect to the development of tailor- made yeast strains for the fermented beverage and biofuel industries.

Adaptation of continuous biogas reactors operating under wet fermentation conditions to dry conditions with corn stover as substrate.

Science.gov (United States)

Kakuk, Balázs; Kovács, Kornél L; Szuhaj, Márk; Rákhely, Gábor; Bagi, Zoltán

2017-08-01

Corn stover (CS) is the agricultural by-product of maize cultivation. Due to its high abundance and high energy content it is a promising substrate for the bioenergy sector. However, it is currently neglected in industrial scale biogas plants, because of its slow decomposition and hydrophobic character. To assess the maximum biomethane potential of CS, long-term batch fermentations were carried out with various substrate concentrations and particle sizes for 72 days. In separate experiments we adapted the biogas producing microbial community in wet fermentation arrangement first to the lignocellulosic substrate, in Continuous Stirred Tank Reactor (CSTR), then subsequently, by continuously elevating the feed-in concentration, to dry conditions in solid state fermenters (SS-AD). In the batch tests, the CSTR experiment, the daily substrate loading was gradually increased from 1 to 2 g vs /L/day until the system produced signs of overloading. Then the biomass was transferred to SS-AD reactors and the adaptation process was studied. Although the specific methane yields were lower in the SS-AD arrangement (177 mL CH 4 /g vs in CSTR vs. 105 mL in SS-AD), the benefits of process operational parameters, i.e. lower energy consumption, smaller reactor volume, digestate amount generated and simpler configuration, may compensate the somewhat lower yield. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

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

Energy Technology Data Exchange (ETDEWEB)

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

1977-07-01

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

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.

Alcoholic glucose and xylose fermentations by the coculture process: Compatability and typing of associated strains

Energy Technology Data Exchange (ETDEWEB)

Laplace, J.M.; Delgenes, J.P.; Moletta, R. (Institut national de la recherche agronomique, Narbonne (France)); Navarro, J.M. (Universite de Montpellier (France))

1992-01-01

As part of the simulaneous fermentation of both glucose and xylose to ethanol by a coculture process, compatibilities between xylose-fermenting yeasts and glucose-fermenting species were investigated. Among the Saccharomyces species tested, none inhibited growth of the xylose-fermenting yeasts. By contrast, many xylose-fermenting yeasts, among the 11 tested, exerted an inhibitory effect on growth of the selected Saccharomyces species. Killer character was demonstrated in three strains of Pichia stipitis. Such strains, despite their high fermentative performances, cannot be used to ferment D-xylose in association with the selected Saccharomyces species. From compatibility tests between xylose-fermenting yeasts and Saccharomyces species, pairs of microorganisms suitable for simultaneous xylose and glucose fermentations by coculture are proposed. Strains associated in the coculture process are distinguished by their resistance to mitochondrial inhibitors. The xylose-fermenting yeasts are able to grow on media containing erythromycin (1 g/l) or diuron (50 mg/l), whereas, the Saccharomyces species are inhibited by these mitochondrial inhibitors. 15 refs., 2 figs., 3 tabs.

Engineering of xylose reductase and overexpression of xylitol dehydrogenase and xylulokinase improves xylose alcoholic fermentation in the thermotolerant yeast Hansenula polymorpha

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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.

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. Copyright © 2015 Elsevier B.V. All rights reserved.

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...... performed. Species specific rates of consumption/formation, as well as yield coefficients were determined. Ethanol yield (0.655 C-mol ethanol*C-mol lactose-1) was as high as 98 % of theoretical. The modeling procedure allowed calculation of maintenance coefficients for lactose consumption and ethanol...

Yeasts are essential for cocoa bean fermentation.

Science.gov (United States)

Ho, Van Thi Thuy; Zhao, Jian; Fleet, Graham

2014-03-17

Cocoa beans (Theobroma cacao) are the major raw material for chocolate production and fermentation of the beans is essential for the development of chocolate flavor precursors. In this study, a novel approach was used to determine the role of yeasts in cocoa fermentation and their contribution to chocolate quality. Cocoa bean fermentations were conducted with the addition of 200ppm Natamycin to inhibit the growth of yeasts, and the resultant microbial ecology and metabolism, bean chemistry and chocolate quality were compared with those of normal (control) fermentations. The yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii and Kluyveromyces marxianus, the lactic acid bacteria Lactobacillus plantarum and Lactobacillus fermentum and the acetic acid bacteria Acetobacter pasteurianus and Gluconobacter frateurii were the major species found in the control fermentation. In fermentations with the presence of Natamycin, the same bacterial species grew but yeast growth was inhibited. Physical and chemical analyses showed that beans fermented without yeasts had increased shell content, lower production of ethanol, higher alcohols and esters throughout fermentation and lesser presence of pyrazines in the roasted product. Quality tests revealed that beans fermented without yeasts were purplish-violet in color and not fully brown, and chocolate prepared from these beans tasted more acid and lacked characteristic chocolate flavor. Beans fermented with yeast growth were fully brown in color and gave chocolate with typical characters which were clearly preferred by sensory panels. Our findings demonstrate that yeast growth and activity were essential for cocoa bean fermentation and the development of chocolate characteristics. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

Solid substrate fermentation

Energy Technology Data Exchange (ETDEWEB)

Tengerdy, R P

1985-04-01

Solid Substrate Fermentation (SSF) describes the microbiological tranformation of biological materials in their natural state, in contrast with liquid or submerged fermentations which are carried out in dilute solutions or slurries. The most important industrial microorganisms used in SSF are filamentous fungi and the critical factors in their growth are the control of the moisture level and the temperature. Traditionally, most SSFs are conducted in shallow trays (so that heat build up is avoided) and stacked in a moist chamber, however, the modern SSF should be able to mix large amounts of substrate for a uniform fermentation, maximum automization scale-up of the process, continuous operation and fermentation control and a promising new design is the Helical screw fermenter. At the present time SSF is used in the production of foods (e.g. mushrooms and oriental foods) in municipal, agricultural and industrial solid waste disposal and in the production of enzymes and speciality chemicals but it does not seem likely that it will replace prevalent liquid fermentation technologies. 29 references.

APPLE VINEGAR PRODUCTION BY FERMENTATION IN PILOT SCALE

OpenAIRE

Reyna M., Leoncio; Robles, R.; Huamán R., M. A.

2014-01-01

Vinegar has been elaborated from apple juice by inmersed fermentation at room temperature. The process was developed in two stages, firstly, the alcoholic termentation was carried out using Saccharomyces Cerevísíae yeast, Ellipsoideus variety. Secondly, an acetic fermentation was carried out using acetobacter. The global yield of the process, based on row material usage was around 52%. The product obtained has an acidity of 6,8% in acetic acid and fulfill the market requirements. Se ha ela...

PERUBAHAN KOMPONEN VOLATIL SELAMA FERMENTASI KECAP [Change Volatile Components During Soy Sauce Fermentation

Directory of Open Access Journals (Sweden)

Anton Apriyantono1

2004-08-01

Full Text Available A study has been conducted to investigate changes of volatile components during soy sauce fermentation. During the fermentation, many volatile components produced may contribute to soy sauce flavor. THe volatile identified by GC-MS werw classified into hydrocarbon (15, alcohol (15, aldehyde (14, ester (14, ketone (9, benzene derivative (11, fatty acid (9, furan (5, terpenoid (18, pyrazine (3, thiazole (1, pyridine (1 and sulfur containing compound (2.Concentration of compounds found in almost all fermentation steps, such as hexanal and benzaldehyde did. These compounds may be derived from raw soybean, since they were all present in raw soybean and their concentration did not change during fermentation. Concentration of palmitic acid and benzeneacetaldehyde, in general, increased during all fermentation steps. They are probably derived from lipid degradation or microorganism activities. Concentrations of some fatty acids, esters and hydrocarbons, such as linoleic acid, methyl palmitate and heptadecane increased during salt fermentation only. Concentration of some other compounds, such as 2,4 decadienal decreased or undetected during fermentation.The absence of some volatile compounds, e.g. (E-nerolidol and (E,E-famesol in boiled soybean which were previously present in raw soybean may be due to evaporation of these compounds during boiling. Some volatile compounds such as, methyl heptadecanoate and few aromatic alcohols are likely derived from Aspergillus sojae, since these compounds were identified only in 0 day koji

Daqu - a traditional Chinese liquor fermentation starter

NARCIS (Netherlands)

Zheng, X.; Rezaei Tabrizi, M.; Nout, M.J.R.; Han, B.

2011-01-01

Chinese liquor is one of the world's oldest distilled alcoholic beverages, and it is typically obtained with the use of Daqufermentation starters. Daqu is a saccharifying and fermenting agent, having a significant impact on the flavour of the product. Daqucan be categorized according to maximum

What Is Alcohol? And Why Do People Drink? Pamphlet Series.

Science.gov (United States)

Milgram, Gail Gleason

Alcoholic beverages have been used throughout American history but their use has always been controversial. Ethyl alcohol is one of the few alcohols man is able to drink, although it is never full strength. The fermentation process is used to manufacture alcoholic beverages. Wines are made from a variety of fruits. Beer is made from yeast and a…

High-temperature crystallization of the secondary alcohol dehydrogenase from the extreme thermophilic bacteria Thermoanaerobacter ethanolicus, a bifunctional alcohol dehydrogenase-acetyl-CoA thio esterase

International Nuclear Information System (INIS)

Watanabe, L.; Arni, R.K.

1996-01-01

Full text. Ethanol fermentations from Saccharomyces sp. are used in industrial ethanol production and are performed at mesophilic temperatures where final ethanol concentrations must exceed 4% (v/v) to make the process industrially economic. In addition, distillation is required to recover ethanol. Thermophilic fermentations are very attractive since they enable separation of ethanol from continuous cultures at process temperature and reduced pressure. Two different ethanol-production pathways have been identified for thermophilic bacteria; type I from Clostridium thermocellum, which contains only NADH-linked primary-alcohol dehydrogeneases, and type II from Thermoanaerobacter brockii which in addition include NADPH-linked secondary-alcohol dehydrogenases. The thermophilic anaerobic bacterium T ethanolicus 39E produces ethanol as the major end product from starch, pentose and herose substrates. The 2 Adh has a lower catalytic efficiency for the oxidation of 1 alcohols, including ethanol, than for the oxidation of secondary (2) alcohols or the reduction of ketones or aldehydes and possesses a significant acetyl-CoA reductive thioesterase activity. Large single crystals (0.7 x 0.3 x 0.3 mn) of this enzyme have been obtained at 40 0 C and diffraction data to 2.7 A resolution has been collected (R merge = 10.44%). Attempts are currently underway to obtain higher resolution data and a search for heavy atom derivatives is currently underway. The crystals belong to the space group P2 1 2 1 2 with cell constants of a a= 170.0 A, b=125.7 A and c=80.5 A. The asymmetric unit contains a tetramer as in the case of the crystals of the secondary alcohol dehydrogenase from Thermoanaerobacter brockii with a V M of 2.85 A 3 /Da. (author)

Metabolite profiling of the fermentation process of "yamahai-ginjo-shikomi" Japanese sake.

Science.gov (United States)

Tatsukami, Yohei; Morisaka, Hironobu; Aburaya, Shunsuke; Aoki, Wataru; Kohsaka, Chihiro; Tani, Masafumi; Hirooka, Kiyoo; Yamamoto, Yoshihiro; Kitaoka, Atsushi; Fujiwara, Hisashi; Wakai, Yoshinori; Ueda, Mitsuyoshi

2018-01-01

Sake is a traditional Japanese alcoholic beverage prepared by multiple parallel fermentation of rice. The fermentation process of "yamahai-ginjo-shikomi" sake is mainly performed by three microbes, Aspergillus oryzae, Saccharomyces cerevisiae, and Lactobacilli; the levels of various metabolites fluctuate during the fermentation of sake. For evaluation of the fermentation process, we monitored the concentration of moderate-sized molecules (m/z: 200-1000) dynamically changed during the fermentation process of "yamahai-ginjo-shikomi" Japanese sake. This analysis revealed that six compounds were the main factors with characteristic differences in the fermentation process. Among the six compounds, four were leucine- or isoleucine-containing peptides and the remaining two were predicted to be small molecules. Quantification of these compounds revealed that their quantities changed during the month of fermentation process. Our metabolomic approach revealed the dynamic changes observed in moderate-sized molecules during the fermentation process of sake, and the factors found in this analysis will be candidate molecules that indicate the progress of "yamahai-ginjo-shikomi" sake fermentation.

Global behavior analysis for stochastic system of 1,3-PD continuous fermentation

Science.gov (United States)

Zhu, Xi; Kliemann, Wolfgang; Li, Chunfa; Feng, Enmin; Xiu, Zhilong

2017-12-01

Global behavior for stochastic system of continuous fermentation in glycerol bio-dissimilation to 1,3-propanediol by Klebsiella pneumoniae is analyzed in this paper. This bioprocess cannot avoid the stochastic perturbation caused by internal and external disturbance which reflect on the growth rate. These negative factors can limit and degrade the achievable performance of controlled systems. Based on multiplicity phenomena, the equilibriums and bifurcations of the deterministic system are analyzed. Then, a stochastic model is presented by a bounded Markov diffusion process. In order to analyze the global behavior, we compute the control sets for the associated control system. The probability distributions of relative supports are also computed. The simulation results indicate that how the disturbed biosystem tend to stationary behavior globally.

Fermentation performance optimization in an ectopic fermentation system.

Science.gov (United States)

Yang, Xiaotong; Geng, Bing; Zhu, Changxiong; Li, Hongna; He, Buwei; Guo, Hui

2018-07-01

Ectopic fermentation systems (EFSs) were developed for wastewater treatment. Previous studies have investigated the ability of thermophilic bacteria to improve fermentation performance in EFS. Continuing this research, we evaluated EFS performance using principle component analysis and investigated the addition of different proportions of cow dung. Viable bacteria communities were clustered and identified using BOX-AIR-based repetitive extragenic palindromic-PCR and 16S rDNA analysis. The results revealed optimal conditions for the padding were maize straw inoculated with thermophilic bacteria. Adding 20% cow dung yielded the best pH values (6.94-8.56), higher temperatures, increased wastewater absorption, improved litter quality, and greater microbial quantities. The viable bacteria groups were enriched by the addition of thermophilic consortium, and exogenous strains G21, G14, G4-1, and CR-15 were detected in fermentation process. The proportion of Bacillus species in treatment groups reached 70.37% after fermentation, demonstrating that thermophilic bacteria, especially Bacillus, have an important role in EFS, supporting previous predictions. Copyright © 2018 Elsevier Ltd. All rights reserved.

An optimum medium designed and verified for alcohol vinegar ...

African Journals Online (AJOL)

In this article, a novel formula of nutrient salt for alcohol vinegar production was derived based on mass conservation theory of carbon source, nitrogen source and inorganic ions. Series of semicontinuous fermentations were successfully carried out in a Frings 10 L fermentation tank. The average acetification rate of ...

Kinetics of alcoholic fermentation during the culturing of bakers' yeast

Energy Technology Data Exchange (ETDEWEB)

Franz, B

1961-01-01

A synthesis was made of the effects of various factors on the rate of fermentation by Saccharomyces cerevisiae. The rate obeyed the Michaelis-Menten equation, was independent of the concentration of yeast, was maximal at 20/sup 0/ (0.61 ml ethanol/g dry yeast/h), was not significantly affected between pH 6.5 and 3.0 but declined at 3.0, was inhibited by ethanol at a rate proportional to the concentration squared (at ethanol = 12 volume %, the fermentation rate was practically zero), and was enhanced by the addition of phosphorus when a P-poor yeast was employed.

Measuring techniques for continuous monitoring of bioreactors

Energy Technology Data Exchange (ETDEWEB)

Kuhlmann, W; Meyer, H D; Schuegerl, K

1982-01-01

Control apparatus for fermentation reactors is described. In the example of alcohol fermentation by Saccharomyces cerevisiae, mass spectrometry is used for measuring soluble volatile components (CO/sub 2/, EtOH, and H/sub 2/O) and low-molecular-weight soluble components are separated by cross flow membrane filtration for measurement: D glucose by polarimetry, phosphate by photometry, and NH/sup 4 +/ by potentiometry.

Effect of phytase application during high gravity (HG) maize mashes preparation on the availability of starch and yield of the ethanol fermentation process.

Science.gov (United States)

Mikulski, D; Kłosowski, G; Rolbiecka, A

2014-10-01

Phytic acid present in raw materials used in distilling industry can form complexes with starch and divalent cations and thus limit their biological availability. The influence of the enzymatic hydrolysis of phytate complexes on starch availability during the alcoholic fermentation process using high gravity (HG) maize mashes was analyzed. Indicators of the alcoholic fermentation as well as the fermentation activity of Saccharomyces cerevisiae D-2 strain were statistically evaluated. Phytate hydrolysis improved the course of the alcoholic fermentation of HG maize mashes. The final ethanol concentration in the media supplemented with phytase applied either before or after the starch hydrolysis increased by 1.0 and 0.6 % v/v, respectively, as compared to the control experiments. This increase was correlated with an elevated fermentation yield that was higher by 5.5 and 2.0 L EtOH/100 kg of starch, respectively. Phytate hydrolysis resulted also in a statistically significant increase in the initial concentration of fermenting sugars by 14.9 mg/mL of mash, on average, which was a consequence of a better availability of starch for enzymatic hydrolysis. The application of phytase increased the attenuation of HG media fermentation thus improving the economical aspect of the ethanol fermentation process.

Diversity of yeasts involved in the fermentation of tchoukoutou, an opaque sorghum beer from Benin

NARCIS (Netherlands)

Kayode, A.P.P.; Vieira-Dalode, G.; Linnemann, A.R.; Kotchoni, S.O.; Hounhouigan, A.J.D.; Boekel, van M.A.J.S.; Nout, M.J.R.

2011-01-01

Opaque sorghum beers are traditional alcoholic beverages in several African countries. Known as tchoukoutou in Benin, the beer is often obtained from an uncontrolled fermentation. It is consumed in an actively fermenting state and has a sour taste. The present study characterized and identified the

Increase of methane formation by ethanol addition during continuous fermentation of biogas sludge.

Science.gov (United States)

Refai, Sarah; Wassmann, Kati; van Helmont, Sebastian; Berger, Stefanie; Deppenmeier, Uwe

2014-12-01

Very recently, it was shown that the addition of acetate or ethanol led to enhanced biogas formation rates during an observation period of 24 h. To determine if increased methane production rates due to ethanol addition can be maintained over longer time periods, continuous reactors filled with biogas sludge were developed which were fed with the same substrates as the full-scale reactor from which the sludge was derived. These reactors are well reflected conditions of a full-scale biogas plant during a period of 14 days. When the fermenters were pulsed with 50-100 mM ethanol, biomethanation increased by 50-150 %, depending on the composition of the biogas sludge. It was also possible to increase methane formation significantly when 10-20 mM pure ethanol or ethanolic solutions (e.g. beer) were added daily. In summary, the experiments revealed that "normal" methane production continued to take place, but ethanol led to production of additional methane.

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluation of Beer Fermentation with a Novel Yeast Williopsis saturnus

Directory of Open Access Journals (Sweden)

Althea Ying Hui Quek

2016-01-01

Full Text Available The aim of this study is to evaluate the potential of a novel yeast Williopsis saturnus var. mrakii NCYC 500 to produce fruity beer. Fermentation performance of W. mrakii and beer volatile composition were compared against that fermented with Saccharomyces cerevisiae Safale US-05. °Brix, sugar and pH differed significantly between the two types of beer. A total of 8 alcohols, 11 acids, 41 esters, 9 aldehydes, 8 ketones, 21 terpenes and terpenoids, 5 Maillard reaction products and 2 volatile phenolic compounds were detected. Yeast strain Safale US-05 was more capable of producing a wider range of ethyl and other esters, while yeast strain NCYC 500 produced significantly higher amounts of acetate esters. Strain NCYC 500 retained more terpenes and terpenoids, suggesting that the resultant beer could possess more of the aromatic hint of hops. This study showed that W. saturnus var. mrakii NCYC 500 could ferment wort to produce low-alcohol beer with higher levels of acetate esters, terpenes and terpenoids than yeast S. cerevisiae Safale US-05.

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.

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.

EFFECT OF TEMPERATURE ON THE PROCESS OF BEER PRIMARY FERMENTATION

Directory of Open Access Journals (Sweden)

Miriam Solgajová

2013-02-01

Full Text Available Beer is a very popular and widespread drink worldwide. Beer may be defined as a foamy alcoholic drink aerated by carbon dioxide that is formed during fermentation. Sensorial and analytical character of beer is mainly formed during process of primary fermentation. Our work has monitored the influence of temperature of fermentation substrate on the process of primary fermentation during beer production. Obtained values of temperature and apparent extract out of four brews of 10% light hopped wort has been recorded, during the process of primary fermentation carried out in mini brewery of SPU. We have compared our results with theoretical values of primary fermentation process commonly achieved in conditions of industrial breweries. It was found out that our results differ in some ways, moreover they exceed theoretically given values which was caused due to different construction of mini brewery fermentation tank in comparison with industrial brewery technologies. Beer produced in mini brewery of SPU showed in sensorial tests very good quality without any strange odour and any strange taste.

Continuous primary fermentation of beer with yeast immobilized on spent grains : the effect of operational conditions

OpenAIRE

Brányik, Tomáš; Vicente, A. A.; Cruz, José Machado; Teixeira, J. A.

2004-01-01

A one-stage continuous primary beer fermentation with immobilized brewing yeast was studied. The objective of the work was to optimize the operational conditions (aeration and temperature) in terms of volumetric productivity and organoleptic quality of green beer. The system consisted of an internal-loop airlift reactor and a carrier material prepared from spent grains (a brewing by-product). An industrial wort and yeast strain were used. The immobilized biomass (in amounts from two to sevenf...

27 CFR 25.55 - Formulas for fermented products.

Science.gov (United States)

2010-04-01

... purposes (including consumer taste testing), produce a fermented product without an approved formula, but... is my formula approval valid? Your formula approved under this section remains in effect until: you... request to the Assistant Chief, Advertising, Labeling and Formulation Division, Alcohol and Tobacco Tax...

Profitability increase of alcohol distilleries by the rational use of sub-products

Energy Technology Data Exchange (ETDEWEB)

Haandel, Adrianus C. van; Catunda, Paula F.C. [Paraiba Univ., Joao Pessoa, PB (Brazil). Dept. de Engenharia Civil

1994-12-31

Industrial alcohol production in Brazil is based on fermentation of sugar cane juice. After concentration and distillation, azeotropic alcohol is obtained along with four side streams. The profitability of alcohol distilleries could be improved by a more rational use of side stream products. An alternative for improved energy production is to abandon alcohol fermentation and apply anaerobic digestion directly to vegetal energy source. In that case the useful energy production is much higher and can be obtained using much simpler equipment. More importantly, the source for energy production would no longer be restricted to sugar cane, but other crops, notably those produced in the drier hinterland of Northeast Brazil could also de used for this purpose. 3 figs., 1 tab.

Profitability increase of alcohol distilleries by the rational use of sub-products

Energy Technology Data Exchange (ETDEWEB)

Haandel, Adrianus C. van; Catunda, Paula F.C. [Paraiba Univ., Joao Pessoa, PB (Brazil). Dept. de Engenharia Civil

1993-12-31

Industrial alcohol production in Brazil is based on fermentation of sugar cane juice. After concentration and distillation, azeotropic alcohol is obtained along with four side streams. The profitability of alcohol distilleries could be improved by a more rational use of side stream products. An alternative for improved energy production is to abandon alcohol fermentation and apply anaerobic digestion directly to vegetal energy source. In that case the useful energy production is much higher and can be obtained using much simpler equipment. More importantly, the source for energy production would no longer be restricted to sugar cane, but other crops, notably those produced in the drier hinterland of Northeast Brazil could also de used for this purpose. 3 figs., 1 tab.

Production and antioxidative activity of alcoholic beverages made ...

African Journals Online (AJOL)

Fermentation yeast was isolated from a Thai traditional alcoholic beverage called Thai ou, which is drunk through bamboo tubes. The isolated yeast was identified as a strain of the genus Saccharomyces cerevisiae. The alcoholic beverage made with the isolated yeast designated as S. cerevisiae NP01 from black rice ...

Microbial diversity and their roles in the vinegar fermentation process.

Science.gov (United States)

Li, Sha; Li, Pan; Feng, Feng; Luo, Li-Xin

2015-06-01

Vinegar is one of the oldest acetic acid-diluted solution products in the world. It is produced from any fermentable sugary substrate by various fermentation methods. The final vinegar products possess unique functions, which are endowed with many kinds of compounds formed in the fermentation process. The quality of vinegar is determined by many factors, especially by the raw materials and microbial diversity involved in vinegar fermentation. Given that metabolic products from the fermenting strains are directly related to the quality of the final products of vinegar, the microbial diversity and features of the dominant strains involved in different fermentation stages should be analyzed to improve the strains and stabilize fermentation. Moreover, although numerous microbiological studies have been conducted to examine the process of vinegar fermentation, knowledge about microbial diversity and their roles involved in fermentation is still fragmentary and not systematic enough. Therefore, in this review, the dominant microorganism species involved in the stages of alcoholic fermentation and acetic acid fermentation of dissimilar vinegars were summarized. We also summarized various physicochemical properties and crucial compounds in disparate types of vinegar. Furthermore, the merits and drawbacks of vital fermentation methods were generalized. Finally, we described in detail the relationships among microbial diversity, raw materials, fermentation methods, physicochemical properties, compounds, functionality, and final quality of vinegar. The integration of this information can provide us a detailed map about the microbial diversity and function involved in vinegar fermentation.

Seed of sweet sorghum: studies on fermentation

Energy Technology Data Exchange (ETDEWEB)

Amaro, F A; Onetto, E; Angeloro, H; Victorio Gugliucci, S

1961-01-01

Both the percentage of starch transformed by saccharification with malt and the alcohol fermentation efficiency for four varieties of sweet sorghum is determined, and it is compared with those of a corn sample. Seeds of the varieties with low peel content yield values comparable to those of corn. Seeds of the varieties with high peel content give values lower than those of the low peel content, but, if they are previously peeled, the yield of both, in terms of transformed starch and alcohol produced, is improved, the values approaching those obtained with corn.

Fortification and Elevated Alcohol Concentration Affect the Concentration of Rotundone and Volatiles in Vitis vinifera cv. Shiraz Wine

Directory of Open Access Journals (Sweden)

Pangzhen Zhang

2017-06-01

Full Text Available Rotundone is a key aromatic compound for cool-climate Shiraz. This compound is produced in the skin of grape berries and extracted into wine during fermentation. This project investigated the influence of fermentation techniques on the concentration of rotundone in the resultant wine. Wine was fortified with ethanol and sucrose on the 1st and 5th days of fermentation and rotundone, volatile aroma compounds and colour were assessed in the resultant wine. The relationship between the concentration of rotundone and alcoholic strength during fermentation process was also investigated. Wine alcoholic strength and skin–wine contact time were two factors affecting rotundone extraction rate from grapes into wine. Fortification significantly enhanced rotundone extraction rate, and improved wine colour and phenolics and affects the concentration of ethyl acetate, 3-methylbutyl acetate, ethyl butanoate, ethyl hexanoate, ethyl octanoate, methyl nonanoate, isopentanol and phenylethyl alcohol in the resultant wine. Understanding how ethanol produced during fermentation can change the extraction of skin-bound aroma compounds and the colour and flavour of wine allows greater control of fermentation parameters to produce quality wine.

Yeast hybrids which ferment raffinose, and their application in the alcohol industry

Energy Technology Data Exchange (ETDEWEB)

Konovalov, S A; Raevskaya, O G; Kosikov, K V

1964-01-01

Saccharomyces carlsbergensis and some hybrids obtained earlier were crossed. Among the newly created hybrids one called hybrid No. 67 is very efficient with respect to the fermentation of raffinose (1). This is of interest in the fermentation of molasses high in I. On an industrial scale this hybrid could be employed to ferment molasses which had been diluted to about 5/sup 0/ Balling so as to produce a solution containing 7.5% ethanol and about 0.4% unfermented sugars, with a cell yield of 148 x 10/sup 6//ml. For molasses containing less than or equal to 4% I, these values can still be increased to 9% and 186 x 10/sup 6//ml, respectively.

Functional analysis of lipid metabolism genes in wine yeasts during alcoholic fermentation at low temperature.

Science.gov (United States)

López-Malo, María; García-Ríos, Estéfani; Chiva, Rosana; Guillamon, José M

2014-10-29

Wine produced by low-temperature fermentation is mostly considered to have improved sensory qualities. However few commercial wine strains available on the market are well-adapted to ferment at low temperature (10 - 15°C). The lipid metabolism of Saccharomyces cerevisiae plays a central role in low temperature adaptation. One strategy to modify lipid composition is to alter transcriptional activity by deleting or overexpressing the key genes of lipid metabolism. In a previous study, we identified the genes of the phospholipid, sterol and sphingolipid pathways, which impacted on growth capacity at low temperature. In the present study, we aimed to determine the influence of these genes on fermentation performance and growth during low-temperature wine fermentations. We analyzed the phenotype during fermentation at the low and optimal temperature of the lipid mutant and overexpressing strains in the background of a derivative commercial wine strain. The increase in the gene dosage of some of these lipid genes, e.g., PSD1 , LCB3, DPL1 and OLE1, improved fermentation activity during low-temperature fermentations, thus confirming their positive role during wine yeast adaptation to cold. Genes whose overexpression improved fermentation activity at 12°C were overexpressed by chromosomal integration into commercial wine yeast QA23. Fermentations in synthetic and natural grape must were carried out by this new set of overexpressing strains. The strains overexpressing OLE1 and DPL1 were able to finish fermentation before commercial wine yeast QA23. Only the OLE1 gene overexpression produced a specific aroma profile in the wines produced with natural grape must.

Pilot plant study for ethanol production

Energy Technology Data Exchange (ETDEWEB)

Kim, J S [Korea Inst. of Science and Technology, Seoul (Korea, Republic of)

1996-02-01

Most of domestic alcohol fermentation factory adopt batch process of which productivity is lower than continuous fermentation process. They have made great effort to increase productivity by means of partial unit process automatization and process improvement with their accumulated experience but there is technical limitation in productivity of batch fermentation process. To produce and supply fuel alcohol, economic aspects must be considered first of all. Therefore, development of continuous fermentation process, of which productivity is high, is prerequisite to produce and use fuel alcohol but only a few foreign company possess continuous fermentation technic and use it in practical industrial scale fermentation. We constructed pilot plant (5 Stage CSTR 1 kl 99.5 v/v% ethanol/Day scale) to study some aspects stated below and our ultimate aims are production of industrial scale fuel alcohol and construction of the plant by ourselves. Some study concerned with energy saving separation and contamination control technic were entrusted to KAIST, A-ju university and KIST respectively. (author) 67 refs., 100 figs., 58 tabs.

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

2016-01-01

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. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Simulation of an alcoholic fermentation, using honey like substrate; Simulacion de una fermentacion alcoholica, utilizando miel de abejas como sustrato

Energy Technology Data Exchange (ETDEWEB)

Gomez, Jose Angel; Castano, Hader Ivan; Mario, Arias

1997-11-01

The article describes the implementation of a mathematical model for the simulation of an alcoholic fermentation using honey like substrate. To carry out it, the kinetic data were adjusted to equations of curves with which were calculated the derivates of the concentrations in the time, with the objective of calculating the specific speeds of growth and product formation; once fact this, it proceeded to evaluate the adjustment of the different inhibition models, so much of substrate as of product on the kinetics of the process, finding that the pattern that more it was adjusted it was the exponential, also working lineal, parabolic model, etc. with the equations for {mu} (specific speed of growth of biomass) and v (specific speed of product formation) it proceeded to carry out the balances of mass, with the purpose of outlining the pattern of differential equations of first order and with conditions given initials. This system was solved for numeric methods using the Euler algorithm modified for that which was required to elaborate a computer program and this way, the behavior of the feigned fermentation, for its later confrontation with the experimental data.

Mechanism of ethanol inhibition of fermentation in Zymomonas mobilis CP4

International Nuclear Information System (INIS)

Osman, Y.A.; Ingram, L.O.

1985-01-01

Accumulation of alcohol during fermentation is accompanied by a progressive decrease in the rate of sugar conversion to ethanol. In this study, the authors provided evidence that inhibition of fermentation by ethanol can be attributed to an indirect effect of ethanol on the enzymes of glycolysis involving the plasma membrane. Ethanol decreased the effectiveness of the plasma membrane as a semipermeable barrier, allowing leakage of essential cofactors and coenzymes. This leakage of cofactors and coenzymes, coupled with possible additional leakage of intermediary metabolites en route to ethanol formation, is sufficient to explain the inhibitory effects of ethanol on fermentation in Zymomonas mobilis

CHANGES IN VOLATILE COMPOSITION OF KRALJEVINA WINES BY CONTROLLED MALOLACTIC FERMENTATION

Directory of Open Access Journals (Sweden)

Ana JEROMEL

2008-11-01

Full Text Available The effect of malolactic fermentation (MLF on the volatile composition of white wines made from autochtonous grape variety Kraljevina was studied by inoculation with selected lactic acid bacteria. At the end of malolactic fermentation, after the decomposition of the malic acid present in wine the non volatile compounds were analyzed by HPLC, while volatile compounds were analyzed by gas chromatography. All wines were also sensory analyzed. Results showed changes in acetaldehyde, some higher alcohols, ethyl esters, free and bound monoterpenes and some organic acids that contribute to enhance the sensory properties and quality of Kraljevina wines that underwent malolactic fermentation.

A study on some efficient parameters in batch fermentation of ...

African Journals Online (AJOL)

USER

2010-05-17

May 17, 2010 ... kinetics of temperature, ethanol concentration, assimi- lable nitrogen, nutrients ... conditions in alcoholic fermentation process by S. cerevesiae SC1 isolated .... in Grapes and Wine, Davis CA: Rantz. J. Am. Soc. Enol. Viticult.

Yeast diversity isolated from grape musts during spontaneous fermentation from a Brazilian winery.

Science.gov (United States)

Bezerra-Bussoli, Carolina; Baffi, Milla Alves; Gomes, Eleni; Da-Silva, Roberto

2013-09-01

Saccharomyces and non-Saccharomyces yeast species from a winery located in Brazil were identified by ribosomal gene-sequencing analysis. A total of 130 yeast strains were isolated from grape surfaces and musts during alcoholic fermentation from Isabel, Bordeaux, and Cabernet Sauvignon varieties. Samples were submitted to PCR-RFLP analysis and genomic sequencing. Thirteen species were identified: Candida quercitrusa, Candida stellata, Cryptococcus flavescens, Cryptococcus laurentii, Hanseniaspora uvarum, Issatchenkia occidentalis, Issatchenkia orientalis, Issatchenkia terricola, Pichia kluyveri, Pichia guilliermondii, Pichia sp., Saccharomyces cerevisiae, and Sporidiobolus pararoseus. A sequential substitution of species during the different stages of fermentation, with a dominance of non-Saccharomyces yeasts at the beginning, and a successive replacement of species by S. cerevisiae strains at the final steps were observed. This is the first report about the yeast distribution present throughout the alcoholic fermentation in a Brazilian winery, providing supportive information for future studies on their contribution to wine quality.

The effects of the fermentation with immobilized yeast and different cherry varieties on the quality of cherry brandy

Directory of Open Access Journals (Sweden)

R. Miličević

2014-01-01

Full Text Available The aim of this research was to investigate influence of different fermentation processes (by immobilized yeast cells and classical fermentation and different cherry varieties (Maraska, Montmorencys and Kelleris on the chemical and sensorial characteristics of cherry brandies. Cherry brandies were analyzed to determine chemical composition, aroma profile and sensory properties. Cherry brandies produced by immobilized yeast cells had a higher content of aldehydes, but lower content of total acids, total extract, higher alcohols and esters compared to the samples produced by classical fermentation process. Furfural was not detected in cherry distillates produced by immobilized yeast cells, while distillates produced by classical fermentation process had very low content. Cherry brandies produced by classical fermentation process had significantly higher content of benzaldehyde which has great influence on aroma of cherry brandies. Ethyl octanoate which is considered one of the most important contributors to the aroma of alcoholic distillates was found in the highest concentrations in Maraska distillates. The best evaluated sample was brandy produced from Maraska cherry variety fermented by immobilized yeast cells followed by brandy produced also from Maraska cherry variety, but by classical fermentation process.

Functional analysis of lipid metabolism genes in wine yeasts during alcoholic fermentation at low temperature

Directory of Open Access Journals (Sweden)

María López-Malo

2014-10-01

Full Text Available Wine produced by low-temperature fermentation is mostly considered to have improved sensory qualities. However few commercial wine strains available on the market are well-adapted to ferment at low temperature (10 – 15°C. The lipid metabolism of Saccharomyces cerevisiae plays a central role in low temperature adaptation. One strategy to modify lipid composition is to alter transcriptional activity by deleting or overexpressing the key genes of lipid metabolism. In a previous study, we identified the genes of the phospholipid, sterol and sphingolipid pathways, which impacted on growth capacity at low temperature. In the present study, we aimed to determine the influence of these genes on fermentation performance and growth during low-temperature wine fermentations. We analyzed the phenotype during fermentation at the low and optimal temperature of the lipid mutant and overexpressing strains in the background of a derivative commercial wine strain. The increase in the gene dosage of some of these lipid genes, e.g., PSD1, LCB3, DPL1 and OLE1, improved fermentation activity during low-temperature fermentations, thus confirming their positive role during wine yeast adaptation to cold. Genes whose overexpression improved fermentation activity at 12°C were overexpressed by chromosomal integration into commercial wine yeast QA23. Fermentations in synthetic and natural grape must were carried out by this new set of overexpressing strains. The strains overexpressing OLE1 and DPL1 were able to finish fermentation before commercial wine yeast QA23. Only the OLE1 gene overexpression produced a specific aroma profile in the wines produced with natural grape must.

Degradation of Aflatoxin B1 during the Fermentation of Alcoholic Beverages

OpenAIRE

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

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...

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

Feasible conditions for converting Cuban cane molasses into alcohol

Energy Technology Data Exchange (ETDEWEB)

Luchev, S

1968-01-01

Conditions for fermentation of Cuban cane molasses were found: 0.5 to 1.0% yeast, addition of 100g. H/sub 3/PO/sub 4/, 1 to 2 kg urea or (NH/sub 4/)/sub 2/SO/sub 4/ to 1 ton molasses, and fermentation at high molasses concentrations. During the process, solid residue formed containing mainly CaSO/sub 4/; this was limited when the molasses was clarified before the fermentation, or when it was distilled without the use of acids (particularly H/sub 2/SO/sub 4/), or when fermented molasses with a low alcohol content was distilled.

Reverse osmosis influence over the content of metals and organic acids in low alcoholic beverages

Directory of Open Access Journals (Sweden)

Andrieş Mitică Tiberiu

2017-01-01

Full Text Available Wine is defined as an alcoholic beverage resulted from fermentation of grape must, having ethanol content higher than 8.5% (v/v. Wine consumption has health benefits related to the high concentration of polyphenolic compounds with antioxidant activity and cardiovascular protection effects. However, the alcohol content restricts wine consumption, but wines with low-alcohol content can be obtained with the help of the dealcoholisation process, after it was produced through alcoholic fermentation. The purpose of this work is to evaluate the organic acid concentration, metal content and other physical-chemical parameters of low alcoholic beverages obtained from grape must by a process which involves reverse osmosis, mixing in a variable ratio the permeate and concentrate and then fermentation. For the experiments, a Muscat Ottonel grape must from Iaşi vineyard was used. There were ten variants of beverages (wines with low alcoholic concentration, by mixing known quantities of the two phases resulting from the reverse osmosis process. These beverages (wines had an alcoholic concentration starting from 2.5% (v/v in the first variant, up to 7% (v/v in the tenth variant. Alcoholic concentration varies for each variant by 0.5% (v/v. After fermentation in 50 L stainless steel tanks, the samples were filtered with 0.45μm sterile membrane and bottled in 0.75 L glass bottles. After 2 months of storage at constant temperature, the beverage samples were analyzed to determine the metal content (AAS method, organic acids concentration (HPLC method, and other physical-chemical characteristics (OIV standard methods. The results obtained indicate that the very complex physical-chemical composition of the low alcoholic beverages analyzed is influenced by the specific chemical composition of a given grape must, as well as by the use of products obtained from reverse osmosis.

A novel gas separation integrated membrane bioreactor to evaluate the impact of self-generated biogas recycling on continuous hydrogen fermentation

International Nuclear Information System (INIS)

Bakonyi, Péter; Buitrón, Germán; Valdez-Vazquez, Idania; Nemestóthy, Nándor; Bélafi-Bakó, Katalin

2017-01-01

Highlights: • A Gas Separation Membrane Bioreactor was designed to improve H_2 production. • Headspace gas after enrichment by PDMS membranes was used for reactor sparging. • Stripping the bioreactor with a CO_2-enriched gas enhanced the H_2 fermentation. - Abstract: A Gas Separation Membrane Bioreactor (GSMBR) by integrating membrane technology with a continuous biohydrogen fermenter was designed. The feasibility of this novel configuration for the improvement of hydrogen production capacity was tested by stripping the fermentation liquor with CO_2- and H_2-enriched gases, obtained directly from the bioreactor headspace. The results indicated that sparging the bioreactor with the CO_2-concentrated fraction of the membrane separation unit (consisting of two PDMS modules) enhanced the steady-state H_2 productivity (8.9–9.2 L H_2/L-d) compared to the membrane-less control CSTR to be characterized with 6.96–7.35 L H_2/L-d values. On the other hand, purging with the H_2-rich gas strongly depressed the achievable productivity (2.7–3.03 L H_2/L-d). Microbial community structure and soluble metabolic products were monitored to assess the GSMBR behavior. The study demonstrated that stripping the bioH_2 fermenter with its own, self-generated atmosphere after adjusting its composition (to higher CO_2-content) can be a promising way to intensify dark fermentative H_2 evolution.

Change of Monascus pigment metabolism and secretion in different extractive fermentation process.

Science.gov (United States)

Chen, Gong; Tang, Rui; Tian, Xiaofei; Qin, Peng; Wu, Zhenqiang

2017-06-01

Monascus pigments that were generally produced intracellularly from Monascus spp. are important natural colorants in food industry. In this study, change of pigment metabolism and secretion was investigated through fed-batch extractive fermentation and continuous extractive fermentation. The biomass, secreting rate of pigment and total pigment yield closely correlated with the activated time of extractive fermentation as well as the composition of feeding nutrients. Metal ions played a key role in both the cell growth and pigment metabolism. Nitrogen source was necessary for a high productivity of biomass but not for high pigment yield. Furthermore, fermentation period for the fed-batch extractive fermentation could be reduced by 18.75% with a nitrogen source free feeding medium. Through a 30-day continuous extractive fermentation, the average daily productivity for total pigments reached 74.9 AU day -1 with an increase by 32.6 and 296.3% compared to that in a 6-day conventional batch fermentation and a 16-day fed-batch extractive fermentation, respectively. At the meantime, proportions of extracellular pigments increased gradually from 2.7 to 71.3%, and yellow pigments gradually became dominated in both intracellular and extracellular pigments in the end of continuous extractive fermentation. This findings showed that either fed-batch or continuous extractive fermentation acted as a promising method in the efficient production of Monascus pigments.

Immobilization of Cells and Enzymes for Fermented Dairy or Meat Products

Science.gov (United States)

Champagne, Claude P.; Lee, Byong H.; Saucier, Linda

Historically, we can find fermented products in almost all cultural backgrounds around the world. Notably, there are many different milk or meat-based foods and this chapter will focus on them (Kosikowski 1982; Wood 1998). Cheese, yoghurt, sour cream, kefir, or cultured butter are probably the most common fermented dairy products, but many regional varieties exist (Farnworth 2004). Fermented meats are typically found as dry sausages (Lüke 1998). Yeasts are mostly involved in the manufacture of bread and alcoholic beverages, which are basically cereal- or fruit-based products. In fermented meat and milk, the main microorganisms used are the lactic acid bacteria (LAB). Yeast and molds are rather involved in ripening. Therefore, the LAB will constitute the main focus of this chapter.

Improving wood hydrolyzate fermentation by using schizosaccharomycetes

Energy Technology Data Exchange (ETDEWEB)

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

1967-01-01

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

Membrane gas sensors for fermentation monitoring

Energy Technology Data Exchange (ETDEWEB)

Mandenius, C F

1987-12-01

Results of a study on membrane gas sensors are presented to show their general applicability to fermentation monitoring of volatiles, such as alcohols, organic acids and aldehydes under various process and reactor conditions. Permeable silicone (Noax AB) and teflon (fluorcarbon AB) are tested as material for a gas sensor. The silicone tubing method is mainly used and ethanolic fermentation is performed in the study. Investigation is made to determine the dependence of the sensitivity of the sensors on the temperature, pH, concentration and other properties of fermentation liquid. The effect of temperature on the ethanol response is investigated in the temperature range of 7-50/sup 0/C to reveal that the response time decreases while the sensor's sensitivity increases with an increasing temperature. Comparison among methanol, ethyl acetate, acetaldehyde and ethanol is made with respect to the effect of their concentration on the sensitivity of a sensor. Results of a three-month measurement with the sensor immersed in fermentation liquid are compared with those of GC analysis to investigate the correlation between the sensor's sensitivity and GC analysis data. (11 figs, 17 refs)

Influence of aeration in the fermentative activity of Kloeckera apiculata during fermentation of apple juice; Influencia de la aireacion en la actividad fermentativa de Kloeckera apiculata durante la fermentacion de jugo de manzana

Energy Technology Data Exchange (ETDEWEB)

Estela Escalante, Waldir D; Rychtera, Mojmir; Melzoch, Karel; Guerrero Ochoa, Manuel R

2012-07-01

The influence of aeration on the fermentative activity of Kloeckera apiculata RIVE 9-2-1 was studied in order to evaluate the production of metabolites of the fermentation. To achieve this, the strain was cultured in Erlenmeyer flasks containing sterilized and aroma removed apple juice, and the chemical compounds produced during fermentation in shaken (200 min-1) and static (without agitation) cultivation were determined. The results showed that the agitation of the culture medium increases production of higher alcohols (till 591.0 mg/L) compared to static cultivation, whereas on the contrary, the production of acetic acid, ethyl acetate and glycerol (260.0 ± 11.0 mg/L, 196.0 ± 10.0 mg/L y 2.6±0.2 g/L) were higher compared to shaken cultivation (222.0 ± 8.0 mg/L, 96.0 ± 4.5 mg/L and 1.8 ± 0.2 g/L) respectively. Batch cultivations carried out in bioreactor with air flux of 25 l/h reported a growth rate μ of 0.17 h-1, production of ethanol (12.5 ± 2.0 g/L) and other compounds typically produced during alcoholic fermentation. The concentration of dissolved oxygen in the fermentation medium affects its metabolism thus; insufficient amounts of oxygen would provoke a respirofermentative metabolism. The best results in terms of organoleptic quality of the fermented beverage regarding to aroma, taste and flavor was obtained when fermented in static cultivation. The control of aeration during fermentation can be used to control the synthesis of chemical compounds of sensory impact in the production of fermented beverages.

Modeling a one-stage continuous ethanol fermentation

Energy Technology Data Exchange (ETDEWEB)

Michalski, H; Wieczorek, A

1974-01-01

Kinetics of the fermentation process carried out with Saccharomyces cerevisiae hybrid G-67 on synthetic media at different initial concentrations of sugar and mixing speed have been determined. No significant effect of mixing (Reynolds No. 1915-7760) and initial sugar concentrations within 50 to 150 g/l was found on the biomass and final ethanol concentration or on the amount of sugar consumed. The optimum dilution rate was 0.10 to 0.20 h/sup -1/. Kinetic equations for sugar and ethanol concentration changes in the process are given.

Lignocellulosic sugar management for xylitol and ethanol fermentation with multiple cell recycling by Kluyveromyces marxianus IIPE453.

Science.gov (United States)

Dasgupta, Diptarka; Ghosh, Debashish; Bandhu, Sheetal; Adhikari, Dilip K

2017-07-01

Optimum utilization of fermentable sugars from lignocellulosic biomass to deliver multiple products under biorefinery concept has been reported in this work. Alcohol fermentation has been carried out with multiple cell recycling of Kluyveromyces marxianus IIPE453. The yeast utilized xylose-rich fraction from acid and steam treated biomass for cell generation and xylitol production with an average yield of 0.315±0.01g/g while the entire glucose rich saccharified fraction had been fermented to ethanol with high productivity of 0.9±0.08g/L/h. A detailed insight into its genome illustrated the strain's complete set of genes associated with sugar transport and metabolism for high-temperature fermentation. A set flocculation proteins were identified that aided in high cell recovery in successive fermentation cycles to achieve alcohols with high productivity. We have brought biomass derived sugars, yeast cell biomass generation, and ethanol and xylitol fermentation in one platform and validated the overall material balance. 2kg sugarcane bagasse yielded 193.4g yeast cell, and with multiple times cell recycling generated 125.56g xylitol and 289.2g ethanol (366mL). Copyright © 2017 Elsevier GmbH. All rights reserved.

Effects of the addition of different nitrogen sources in the tequila fermentation process at high sugar concentration.

Science.gov (United States)

Arrizon, J; Gschaedler, A

2007-04-01

To study the effect of the addition of different nitrogen sources at high sugar concentration in the tequila fermentation process. Fermentations were performed at high sugar concentration (170 g l(-1)) using Agave tequilana Weber blue variety with and without added nitrogen from different sources (ammonium sulfate; glutamic acid; a mixture of ammonium sulfate and amino acids) during the exponential phase of growth. All the additions increased the fermentation rate and alcohol efficiency. The level of synthesis of volatile compounds depended on the source added. The concentration of amyl alcohols and isobutanol were decreased while propanol and acetaldehyde concentration increased. The most efficient nitrogen sources for fermentation rate were ammonium sulfate and the mixture of ammonium sulfate and amino acids. The level of volatile compounds produced depended upon types of nitrogen. The synthesis of some volatile compounds increased while others decreased with nitrogen addition. The addition of nitrogen could be a strategy for improving the fermentation rate and efficiency in the tequila fermentation process at high sugar Agave tequilana concentration. Furthermore, the sensory quality of the final product may change because the synthesis of the volatile compounds is modified.

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

Science.gov (United States)

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

2011-03-01

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

Development of a Fermented, Low-alcoholic Cherry-based Beverage

DEFF Research Database (Denmark)

Kristensen, Mia Irene

2015-01-01

Formålet med dette projekt var at udvikle en fermenteret, lav-alkoholisk drik baseret på lokale surkirsebær. Systematisk idegenerering blev brugt i de første faser af ideudviklingen. To forskellige vine blev brygget, ved brug af samme metode til fermentering af saft fra lokale ”Stevnsbær” surkirs......Formålet med dette projekt var at udvikle en fermenteret, lav-alkoholisk drik baseret på lokale surkirsebær. Systematisk idegenerering blev brugt i de første faser af ideudviklingen. To forskellige vine blev brygget, ved brug af samme metode til fermentering af saft fra lokale ”Stevnsbær...... opbevaring ved 25°C. Alle behandlinger, på nær tilsætning af kaliumsorbat, sikrede den mikrobielle stabilitet and ingen vækst blev observeret disse blandinger. To kirsebærvinsblandinger blev valgt til videre udvikling L9-(50:50) and FR-(25:75) (vin:juice).Til slut blev Busines Model Canvas brugt til...

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

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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.

Monitoring of Yeast Communities and Volatile Flavor Changes During Traditional Korean Soy Sauce Fermentation.

Science.gov (United States)

Song, Young-Ran; Jeong, Do-Youn; Baik, Sang-Ho

2015-09-01

Flavor development in soy sauce is significantly related to the diversity of yeast species. Due to its unique fermentation with meju, the process of making Korean soy sauce gives rise to a specific yeast community and, therefore, flavor profile; however, no detailed analysis of the identifying these structure has been performed. Changes in yeast community structure during Korean soy sauce fermentation were examined using both culture-dependent and culture-independent methods with simultaneous analysis of the changes in volatile compounds by GC-MS analysis. During fermentation, Candida, Pichia, and Rhodotorula sp. were the dominant species, whereas Debaryomyces, Torulaspora, and Zygosaccharomyces sp. were detected only at the early stage. In addition, Cryptococcus, Microbotryum, Tetrapisispora, and Wickerhamomyces were detected as minor strains. Among the 62 compounds identified in this study, alcohols, ketones, and pyrazines were present as the major groups during the initial stages, whereas the abundance of acids with aldehydes increased as the fermentation progressed. Finally, the impacts of 10 different yeast strains found to participate in fermentation on the formation of volatile compounds were evaluated under soy-based conditions. It was revealed that specific species produced different profiles of volatile compounds, some of which were significant flavor contributors, especially volatile alcohols, aldehydes, esters, and ketones. © 2015 Institute of Food Technologists®

Characteristics of Milk Fermented by Streptococcus thermophilus MGA45-4 and the Profiles of Associated Volatile Compounds during Fermentation and Storage.

Science.gov (United States)

Dan, Tong; Jin, Rulin; Ren, Weiyi; Li, Ting; Chen, Haiyan; Sun, Tiansong

2018-04-11

The lactic acid bacterium Streptococcus thermophilus is a major starter culture for the production of dairy products. In this study, the physiochemical characteristics of milk fermented by the MGA45-4 isolate of S. thermophilus were analyzed. Our data indicate that milk fermented using S. thermophilus MGA45-4 maintained a high viable cell count (8.86 log10 colony-forming units/mL), and a relatively high pH (4.4), viscosity (834.33 mPa·s), and water holding capacity (40.85%) during 14 days of storage. By analyzing the volatile compound profile using solid-phase microextraction and gas chromatography/mass spectrometry, we identified 73 volatile compounds in the fermented milk product, including five carboxylic acids, 21 aldehydes, 13 ketones, 16 alcohols, five esters, and 13 aromatic carbohydrates. According to the odor activity values, 11 of these volatile compounds were found to play a key role in producing the characteristic flavor of fermented milk, particularly octanal, nonanal, hexanal, 2,3-butanedione, and 1-octen-3-ol, which had the highest odor activity values among all compounds analyzed. These findings thus provide more insights in the chemical/molecular characteristics of milk fermented using S. thermophilus , which may provide a basis for improving dairy product flavor/odor during the process of fermentation and storage.

Esterification of Fatty Acids with Short-Chain Alcohols over Commercial Acid Clays in a Semi-Continuous Reactor

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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.

Diversity of yeasts involved in the fermentation of tchoukoutou, an opaque sorghum beer from Benin

OpenAIRE

Kayode, A.P.P.; Vieira-Dalode, G.; Linnemann, A.R.; Kotchoni, S.O.; Hounhouigan, A.J.D.; Boekel, van, M.A.J.S.; Nout, M.J.R.

2011-01-01

Opaque sorghum beers are traditional alcoholic beverages in several African countries. Known as tchoukoutou in Benin, the beer is often obtained from an uncontrolled fermentation. It is consumed in an actively fermenting state and has a sour taste. The present study characterized and identified the yeasts involved in the fermentation process of this type of beer using the phenotypical approach. Of 12 beers from 4 different locations, the mean values of the pH, titratable acidity, dry matter c...

Bioprocess Intensification of Beer Fermentation Using Immobilised Cells

Science.gov (United States)

Verbelen, Pieter J.; Nedović, Viktor A.; Manojlović, Verica; Delvaux, Freddy R.; Laskošek-Čukalović, Ida; Bugarski, Branko; Willaert, Ronnie

Beer production with immobilised yeast has been the subject of research for approximately 30 years but has so far found limited application in the brewing industry, due to engineering problems, unrealised cost advantages, microbial contaminations and an unbalanced beer flavor (Linko et al. 1998; Brányik et al. 2005; Willaert and Nedović 2006). The ultimate aim of this research is the production of beer of desired quality within 1-3 days. Traditional beer fermentation systems use freely suspended yeast cells to ferment wort in an unstirred batch reactor. The primary fermentation takes approximately 7 days with a subsequent secondary fermentation (maturation) of several weeks. A batch culture system employing immobilization could benefit from an increased rate of fermentation. However, it appears that in terms of increasing productivity, a continuous fermentation system with immobilization would be the best method (Verbelen et al. 2006). An important issue of the research area is whether beer can be produced by immobilised yeast in continuous culture with the same characteristic as the traditional method.

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.

Design and Investigation of PolyFermS In Vitro Continuous Fermentation Models Inoculated with Immobilized Fecal Microbiota Mimicking the Elderly Colon.

Directory of Open Access Journals (Sweden)

Sophie Fehlbaum

Full Text Available 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.

Volatile components of the enzyme-ripened sufu, a Chinese traditional fermented product of soy bean.

Science.gov (United States)

Moy, Yin-Soon; Lu, Ting-Jang; Chou, Cheng-Chun

2012-02-01

In the present study, sufu, a soft cheese-like oriental fermented food, was prepared by ripening the salted-tofu cubes in Aspergillus oryzae-fermented soybean-rice koji at 37°C for 16 days (16-day sufu). Sufu was further held at room temperature for another 30 days (46-day sufu). The volatile components of the non-fermented tofu cubes and the sufu products were identified and quantified by GC and GC-MS. A total of 70 volatile compounds including 20 aldehydes, 18 alcohols, 16 esters, 5 ketones, 5 acids and 6 other compounds were identified. Sufu products contained more volatile compounds than non-fermented tofu cubes qualitatively and quantitatively. After 16-days of ripening, fatty acid, aldehyde and ester were noted to be the dominant volatile fractions. In contrast, the 46-day sufu contained ester, and alcohol as the major volatile fractions. They comprise approximately 63.9% of the total volatile components. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Culture-independent analysis of lactic acid bacteria diversity associated with mezcal fermentation.

Science.gov (United States)

Narváez-Zapata, J A; Rojas-Herrera, R A; Rodríguez-Luna, I C; Larralde-Corona, C P

2010-11-01

Mezcal is an alcoholic beverage obtained from the distillation of fermented juices of cooked Agave spp. plant stalks (agave must), and each region in Mexico with denomination of origin uses defined Agave species to prepare mezcal with unique organoleptic characteristics. During fermentation to produce mezcal in the state of Tamaulipas, not only alcohol-producing yeasts are involved, but also a lactic acid bacterial community that has not been characterized yet. In order to address this lack of knowledge on this traditional Mexican beverage, we performed a DGGE-16S rRNA analysis of the lactic acid bacterial diversity and metabolite accumulation during the fermentation of a typical agave must that is rustically produced in San Carlos County (Tamaulipas, Mexico). The analysis of metabolite production indicated a short but important malolactic fermentation stage not previously described for mezcal. The denaturing gradient gel electrophoresis (DGGE) analysis of the 16S rRNA genes showed a distinctive lactic acid bacterial community composed mainly of Pediococcus parvulus, Lactobacillus brevis, Lactobacillus composti, Lactobacillus parabuchneri, and Lactobacillus plantarum. Some atypical genera such as Weissella and Bacillus were also found in the residual must. Our results suggest that the lactic acid bacteria could strongly be implicated in the organoleptic attributes of this traditional Mexican distilled beverage.

The availability of a lactose medium for tea fungus culture and Kombucha fermentation

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Markov S.L.

2012-01-01

Full Text Available Kombucha is a traditional beverage that is prepared by fermenting sucrose-sweetened black tea. A medium is inoculated with a cellulose pellicle (popularly known as a “tea fungus” or fermentation brought from previous cultivation process. Our aim was to test the possibility of obtaining a Kombucha beverage using different concentration of lactose as an alternative source of C-atoms. A traditional medium sweetened with sucrose or without sugar was used as control. Without lactose-fermenting yeast strains in tea fungus, lactose is not an adequate alternative source of the C-atom for Kombucha fermentation because it is not possible to obtain Kombucha with an appropriate acidity during a seven-day fermentation. Compared with the traditional medium, fermentation is significantly slower with high differences in acid content. In unsweetened tea inoculated with the beverage obtained from a previous traditional process, Kombucha fermentation processes and produces a beverage without sugar and alcohol. [Projekat Ministarstva nauke Republike Srbije, br. TR 31044

Continuous citric acid production in repeated-fed batch fermentation by Aspergillus niger immobilized on a new porous foam.

Science.gov (United States)

Yu, Bin; Zhang, Xin; Sun, Wenjun; Xi, Xun; Zhao, Nan; Huang, Zichun; Ying, Zhuojun; Liu, Li; Liu, Dong; Niu, Huanqing; Wu, Jinglan; Zhuang, Wei; Zhu, Chenjie; Chen, Yong; Ying, Hanjie

2018-03-24

The efficiency of current methods for industrial production of citric acid is limited. To achieve continuous citric acid production with enhanced yield and reduced cost, immobilized fermentation was employed in an Aspergillus niger 831 repeated fed-batch fermentation system. We developed a new type of material (PAF201), which was used as a carrier for the novel adsorption immobilization system. Hydrophobicity, pore size and concentration of carriers were researched in A. niger immobilization. The efficiency of the A. niger immobilization process was analyzed by scanning electron microscopy. Then eight-cycle repeated fed-batch cultures for citric acid production were carried out over 600 h, which showed stable production with maximum citric acid concentrations and productivity levels of 162.7 g/L and 2.26 g L -1  h -1 , respectively. Compared with some other literatures about citric acid yield, PAF201 immobilization system is 11.3% higher than previous results. These results indicated that use of the new adsorption immobilization system could greatly improve citric acid productivity in repeated fed-batch fermentation. Moreover, these results could provide a guideline for A.niger or other filamentous fungi immobilization in industry. Copyright © 2018 Elsevier B.V. All rights reserved.

Fermentation process for production of apple-based kefir vinegar: microbiological, chemical and sensory analysis

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Roberta Oliveira Viana

Full Text Available Abstract The aim of this study was to develop a kefir apple-based vinegar and evaluate this fermentation process using new methodology with Biospeckle Laser. Brazilian kefir grains were inoculated in apple must for vinegar production. In this study, the microbial community present in kefir, and correspondent vinegar, was investigated using Matrix Assisted Laser Desorption/Ionization - Time of Flight Mass Spectrometry (MALDI-TOF MS technique. Saccharomyces cerevisiae, Lactobacillus paracasei, Lactobacillus plantarum, Acetobacter pasteurianus and Acetobacter syzygii were the microbial species identified. S. cerevisiae, L. plantarum, A. pasteurianus and A. syzygii were found in smaller quantities at the beginning of the alcoholic fermentation, but were found throughout the alcoholic and acetic fermentation. Kefir grains were able to utilize apple must as substrate to produce ethanol, and acetic acid. Acetate, volatile alcohols and aldehydes in the vinegar-based kefir were also produced. The yield of acetic acid in the kefir vinegars was ∼79%. The acetic acid concentration was ∼41 g L-1, reaching the required standard for the Brazilian legislation accepts it as vinegar (4.0% acetic acid. Kefir vinegar showed good acceptance in the sensory analysis. The technology proposed here is novel by the application of immobilized-cell biomass (kefir grains providing a mixed inocula and eliminating the use of centrifuge at the end of the fermentative process. This step will save energy demand and investment. This is the first study to produce apple vinegar using kefir grains.

Fermentation process for production of apple-based kefir vinegar: microbiological, chemical and sensory analysis.

Science.gov (United States)

Viana, Roberta Oliveira; Magalhães-Guedes, Karina Teixeira; Braga, Roberto Alves; Dias, Disney Ribeiro; Schwan, Rosane Freitas

The aim of this study was to develop a kefir apple-based vinegar and evaluate this fermentation process using new methodology with Biospeckle Laser. Brazilian kefir grains were inoculated in apple must for vinegar production. In this study, the microbial community present in kefir, and correspondent vinegar, was investigated using Matrix Assisted Laser Desorption/Ionization - Time of Flight Mass Spectrometry (MALDI-TOF MS) technique. Saccharomyces cerevisiae, Lactobacillus paracasei, Lactobacillus plantarum, Acetobacter pasteurianus and Acetobacter syzygii were the microbial species identified. S. cerevisiae, L. plantarum, A. pasteurianus and A. syzygii were found in smaller quantities at the beginning of the alcoholic fermentation, but were found throughout the alcoholic and acetic fermentation. Kefir grains were able to utilize apple must as substrate to produce ethanol, and acetic acid. Acetate, volatile alcohols and aldehydes in the vinegar-based kefir were also produced. The yield of acetic acid in the kefir vinegars was ∼79%. The acetic acid concentration was ∼41gL -1 , reaching the required standard for the Brazilian legislation accepts it as vinegar (4.0% acetic acid). Kefir vinegar showed good acceptance in the sensory analysis. The technology proposed here is novel by the application of immobilized-cell biomass (kefir grains) providing a mixed inocula and eliminating the use of centrifuge at the end of the fermentative process. This step will save energy demand and investment. This is the first study to produce apple vinegar using kefir grains. Copyright © 2017. Published by Elsevier Editora Ltda.

Continuous fermentative hydrogen production from coffee drink manufacturing wastewater by applying UASB reactor

Energy Technology Data Exchange (ETDEWEB)

Jung, Kyung-Won; Shin, Hang-Sik [Department of Civil and Environmental Engineering, KAIST, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kim, Dong-Hoon [Department of Civil and Environmental Engineering, University of Windsor, 401 Sunset Ave., Essex Hall, Windsor, Ontario (Canada)

2010-12-15

The feasibility of continuous H{sub 2} production from coffee drink manufacturing wastewater (CDMW) was tested in two different types of reactors: a completely-stirred tank reactor (CSTR) and an up-flow anaerobic sludge blanket reactor (UASBr). While the performance in CSTR was limited, it was significantly enhanced in UASBr. The maximum H{sub 2} yield of 1.29 mol H{sub 2}/mol hexose{sub added} was achieved at HRT of 6 h in UASBr operation. Non-hydrogenic, lactic acid was the dominant in CSTR, while butyric and caproic acids in UASBr. As caproic acid is generated by consuming acetic and butyric acids, all of which are related to H{sub 2} production, the presence of caproic acid in the broth also indicates H{sub 2} production, yielding 1.33 mol H{sub 2}/glucose. It was speculated that the enhanced performance in UASBr was attributed to the high concentration of biomass over 60,000 mg VSS/L in the blanket zone, which provided insufficient substrate for indigenous lactic acid bacteria (LAB) to survive. The abundance of LAB in CDMW was confirmed by natural fermentation of CDMW. That is without the addition of external inoculum, CDMW was mainly fermented into lactic acid under mesophilic condition. For the first time ever, H{sub 2} producing granules (HPG) with diameters of 2.1 mm were successfully formed by using actual waste as a substrate. (author)

The effect of diet supplemented with vegetable oils and/or monensin on the vaccenic acid production in continuous culture fermenters

Directory of Open Access Journals (Sweden)

Mostafa Sayed A. Khattab

2015-12-01

Full Text Available Studies have shown that supplementing ruminant diets with vegetable oils modulated the rumen biohydrogenation and increased polyunsaturated fatty acid in their products. These positive values are often accompanied by a marginal loss of supplemented unsaturated fatty acids and rise in the concentrations of saturated fatty acids. This study were carried out mainly to investigate the effect of supplementing diets with sunflower oil, olive oil with or without monensin on the production and accumulation of vaccenic acid (VA in continuous culture fermenters as a long term in vitro rumen simulation technique. Eight dual-flow continuous culture fermenters were used in an 8 replication experiment lasted 10 days each (first 7 days for adaptation and last 3 days for samples collection. Supplementing diets with plant oils and monensin in the present experiment increased VA and conjugated linoleic acids (P > 0.05 in ruminal cultures. The results suggest that supplementing diets with both olive oil and sunflower oil and monensin increased VA accumulation compared to plant oils supplemented alone without affecting the rumen dry matter and organic matter digestibility.

Fermentation of molasses-flour mashes by acetone-butanol bacteria

Energy Technology Data Exchange (ETDEWEB)

Chekasina, E V

1962-01-01

With Clostridium acetobutylicum used in a continuous fermentation, where the mash passes through 5 to 12 fermenters, sufficient conversion of starch to mono- and disaccharides will occur; the number of fermenters were chosen and mash changed so that fresh mash remains for 34 hours in the cycle. After a 29 hour fermentation average yields were: acetone 4.5, ethanol 3.0, butanol 7.5%.

Batch pervaporative fermentation with coupled membrane and its influence on energy consumption in permeate recovery and distillation stage

International Nuclear Information System (INIS)

Leon, Juan A.; Palacios-Bereche, Reynaldo; Nebra, Silvia A.

2016-01-01

In the ethanol production process from sugarcane molasses, the distillation process is a high-energy demand stage. The distillation energy efficiency is strongly associated with the alcoholic fermentation performance in the process. The final ethanol concentration in the alcoholic wines has a direct impact on consumption of thermal energy in ethanol separation. In this paper, ethanol production with a H-SBMF (Hybrid-Simple Batch Membrane Fermenter) using PDMS (polydimethylsiloxane) pervaporation membrane was modelled and simulated, in order to determine its influence on energy consumption in distillation. Steam in distillation and electrical energy needs in permeate recovery were mainly influenced by membrane adaptation. The H-SBMF achieved a higher ethanol production in the range of 10–13% compared to the conventional batch fermenter, and an increase in productivity of 150%. The distillation system consisted of two sets of columns: the ethanol recovery column and the rectification column. The permeate recovery system (i.e. vacuum and compression) was regarded in order to evaluate the electrical energy requirement, and the thermal energy demand was evaluated. A decrease in steam consumption was evidenced by the adaptation of the membrane to the fermenter. Higher energy efficiencies were achieved in distillation with larger membrane areas, achieving almost 17% steam reduction. - Highlights: • Higher and faster ethanol productions were achieved by fermenter hybridization. • Multi-stage permeate compression and inter-stage heat recovery were assumed. • Energy demand was studied based on an integrated fermentation and distillation scheme. • High-energy efficiency was attained in the distillation to produce hydrated alcohol.

Biohydrogen production from combined dark-photo fermentation under a high ammonia content in the dark fermentation effluent

Energy Technology Data Exchange (ETDEWEB)

Chen, Chun-Yen [National Cheng Kung Univ., Tainan, Taiwan (China). Dept. of Chemical Engineering; National Cheng Kung Univ., Tainan, Taiwan (China). Sustainable Environment Research Center; Lo, Yung-Chung; Yeh, Kuei-Ling [National Cheng Kung Univ., Tainan, Taiwan (China). Dept. of Chemical Engineering; Chang, Jo-Shu [National Cheng Kung Univ., Tainan, Taiwan (China). Dept. of Chemical Engineering; National Cheng Kung Univ., Tainan, Taiwan (China). Sustainable Environment Research Center; National Cheng Kung Univ., Tainan, Taiwan (China). Microalgae Biotechnology and Bioengineering Lab.

2010-07-01

Integrated dark and photo (two-stage) fermentation was employed to enhance the performance of H{sub 2} production. First, the continuous dark fermentation using indigenous Clostridium butyricum CGS5 was carried out at 12 h HRT and fed with sucrose at a concentration of 18750 mg/l. The overall H{sub 2} production rate and H{sub 2} yield were fairly stable with a mean value of 87.5 ml/l/h and 1.015 mol H{sub 2}/mol sucrose, respectively. In addition, a relatively high ammonia nitrogen content (574 mg/l) in the dark fermentation effluent was observed. The soluble metabolites from dark fermentation, consisting mainly of butyric, lactic and acetic acids, were directly used as the influent of continuous photo-H{sub 2} production process inoculated with Rhodopseudomonas palutris WP 3-5 under the condition of 35oC, 10000 lux irradiation, pH 7.0 and 48 h HRT. The maximum overall hydrogen production rate from photo fermentation was 16.4 ml H{sub 2}/l/h, and the utilization of the soluble metabolites could reach 90%. The maximum H{sub 2} yield dramatically increased from 1.015 mol H{sub 2}/mol sucrose (in dark fermentation only) to 6.04 mol H{sub 2}/mol sucrose in the combined dark and photo fermentation. Surprisingly, the operation strategy applied in this work was able to attain an average NH{sub 3}-N removal efficiency of 92%, implying that our photo-H{sub 2} production system has a higher NH{sub 3}-N tolerance, demonstrating its high applicability in an integrated dark-photo fermentation system. (orig.)

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...... method with bandpass filtering of in- and output variables in order to ensure low frequency validity of the estimated model. An LQ-regulator is used with iterative solution of the Riccati equation. Simulation results illustrate the tuning of the underlying regulator, and the effect of perturbing...

Metabolic and transcriptomic response of the wine yeast Saccharomyces cerevisiae strain EC1118 after an oxygen impulse under carbon-sufficient, nitrogen-limited fermentative conditions.

Science.gov (United States)

Orellana, Marcelo; Aceituno, Felipe F; Slater, Alex W; Almonacid, Leonardo I; Melo, Francisco; Agosin, Eduardo

2014-05-01

During alcoholic fermentation, Saccharomyces cerevisiae is exposed to continuously changing environmental conditions, such as decreasing sugar and increasing ethanol concentrations. Oxygen, a critical nutrient to avoid stuck and sluggish fermentations, is only discretely available throughout the process after pump-over operation. In this work, we studied the physiological response of the wine yeast S. cerevisiae strain EC1118 to a sudden increase in dissolved oxygen, simulating pump-over operation. With this aim, an impulse of dissolved oxygen was added to carbon-sufficient, nitrogen-limited anaerobic continuous cultures. Results showed that genes related to mitochondrial respiration, ergosterol biosynthesis, and oxidative stress, among other metabolic pathways, were induced after the oxygen impulse. On the other hand, mannoprotein coding genes were repressed. The changes in the expression of these genes are coordinated responses that share common elements at the level of transcriptional regulation. Beneficial and detrimental effects of these physiological processes on wine quality highlight the dual role of oxygen in 'making or breaking wines'. These findings will facilitate the development of oxygen addition strategies to optimize yeast performance in industrial fermentations. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Use of Torulaspora delbrueckii Co-fermentation With Two Saccharomyces cerevisiae Strains With Different Aromatic Characteristic to Improve the Diversity of Red Wine Aroma Profile.

Science.gov (United States)

Zhang, Bo-Qin; Luan, Yu; Duan, Chang-Qing; Yan, Guo-Liang

2018-01-01

The use of selected Saccharomyces and non- Saccharomyces strains as mixed starters has advantages over pure fermentation due to achieving wine products with distinctive and diversified aroma expected by consumers. To obtain a way to improve the aroma diversity and increase the differentiation of wine product, in this study, the aromatic effect of multi-culture of indigenous Torulaspora delbrueckii ( TD 12), simultaneous and sequential inoculation with two Saccharomyces strains (indigenous icewine yeast SC 45 and commercial yeast BDX) with different enological characteristics were investigated in laboratory-scale 20 L fermenter, respectively. The results showed that T. delbrueckii co-fermented with different S. cerevisiae strain could generate diversified physicochemical and aromatic quality of wine as evidenced by PCA. Mixed fermentation of SC 45/ TD 12 produced higher contents of higher alcohol (3-methyl-1-pentanol and phenylethyl alcohol), ethyl esters (ethyl decanoate and ethyl butanoate), terpenes and phenylacetaldehyde with less fatty acids (hexanoic acid, octanoic acid) and acetic acid, while BDX/ TD 12 generated more C 6 alcohol (1-hexanol) and acetate esters (ethyl acetate and isoamyl acetate). Compared to simultaneous inoculation, sequential inoculation could achieve higher aroma diversity, and generate higher intensity of fruity, flowery and sweet attributes of wine as assessed by calculating the odor activity values. The different S. cerevisiae strain and inoculation method in alcoholic fermentation could further influence the formations of aromatic compounds in malolactic fermentation. Our results highlighted the importance of S. cerevisiae strain in shaping the aromatic quality of wine in mixed fermentation, and also suggested that using different S. cerevisiae strains with distinct aromatic characteristics co-fermentation with specific non- Saccharomyces strain is a potential way to increase the aromatic diversity and quality of wine product, which

Use of Torulaspora delbrueckii Co-fermentation With Two Saccharomyces cerevisiae Strains With Different Aromatic Characteristic to Improve the Diversity of Red Wine Aroma Profile

Directory of Open Access Journals (Sweden)

Bo-Qin Zhang

2018-04-01

Full Text Available The use of selected Saccharomyces and non-Saccharomyces strains as mixed starters has advantages over pure fermentation due to achieving wine products with distinctive and diversified aroma expected by consumers. To obtain a way to improve the aroma diversity and increase the differentiation of wine product, in this study, the aromatic effect of multi-culture of indigenous Torulaspora delbrueckii (TD12, simultaneous and sequential inoculation with two Saccharomyces strains (indigenous icewine yeast SC45 and commercial yeast BDX with different enological characteristics were investigated in laboratory-scale 20 L fermenter, respectively. The results showed that T. delbrueckii co-fermented with different S. cerevisiae strain could generate diversified physicochemical and aromatic quality of wine as evidenced by PCA. Mixed fermentation of SC45/TD12 produced higher contents of higher alcohol (3-methyl-1-pentanol and phenylethyl alcohol, ethyl esters (ethyl decanoate and ethyl butanoate, terpenes and phenylacetaldehyde with less fatty acids (hexanoic acid, octanoic acid and acetic acid, while BDX/TD12 generated more C6 alcohol (1-hexanol and acetate esters (ethyl acetate and isoamyl acetate. Compared to simultaneous inoculation, sequential inoculation could achieve higher aroma diversity, and generate higher intensity of fruity, flowery and sweet attributes of wine as assessed by calculating the odor activity values. The different S. cerevisiae strain and inoculation method in alcoholic fermentation could further influence the formations of aromatic compounds in malolactic fermentation. Our results highlighted the importance of S. cerevisiae strain in shaping the aromatic quality of wine in mixed fermentation, and also suggested that using different S. cerevisiae strains with distinct aromatic characteristics co-fermentation with specific non-Saccharomyces strain is a potential way to increase the aromatic diversity and quality of wine product, which

Use of Torulaspora delbrueckii Co-fermentation With Two Saccharomyces cerevisiae Strains With Different Aromatic Characteristic to Improve the Diversity of Red Wine Aroma Profile

Science.gov (United States)

Zhang, Bo-Qin; Luan, Yu; Duan, Chang-Qing; Yan, Guo-Liang

2018-01-01

The use of selected Saccharomyces and non-Saccharomyces strains as mixed starters has advantages over pure fermentation due to achieving wine products with distinctive and diversified aroma expected by consumers. To obtain a way to improve the aroma diversity and increase the differentiation of wine product, in this study, the aromatic effect of multi-culture of indigenous Torulaspora delbrueckii (TD12), simultaneous and sequential inoculation with two Saccharomyces strains (indigenous icewine yeast SC45 and commercial yeast BDX) with different enological characteristics were investigated in laboratory-scale 20 L fermenter, respectively. The results showed that T. delbrueckii co-fermented with different S. cerevisiae strain could generate diversified physicochemical and aromatic quality of wine as evidenced by PCA. Mixed fermentation of SC45/TD12 produced higher contents of higher alcohol (3-methyl-1-pentanol and phenylethyl alcohol), ethyl esters (ethyl decanoate and ethyl butanoate), terpenes and phenylacetaldehyde with less fatty acids (hexanoic acid, octanoic acid) and acetic acid, while BDX/TD12 generated more C6 alcohol (1-hexanol) and acetate esters (ethyl acetate and isoamyl acetate). Compared to simultaneous inoculation, sequential inoculation could achieve higher aroma diversity, and generate higher intensity of fruity, flowery and sweet attributes of wine as assessed by calculating the odor activity values. The different S. cerevisiae strain and inoculation method in alcoholic fermentation could further influence the formations of aromatic compounds in malolactic fermentation. Our results highlighted the importance of S. cerevisiae strain in shaping the aromatic quality of wine in mixed fermentation, and also suggested that using different S. cerevisiae strains with distinct aromatic characteristics co-fermentation with specific non-Saccharomyces strain is a potential way to increase the aromatic diversity and quality of wine product, which could provide

Reeds as potential sources of alcohol

Energy Technology Data Exchange (ETDEWEB)

Lodh, A B; Rao, P R

1964-01-01

Five species of reeds, Erianthus ravennae, Saccharum munja S. procerum, Phragmites communis, and Neyraudia reynaudiana yielded 25.02, 19.5, 24.11, 26.1, and 21.6% reducing sugars, repectively., when digested with 1% H/sub 2/SO/sub 4/ under 15lb/square inch for 3 hours. Fermentable sugars from hydrolyzates of the above reeds were 70.0, 34.5, 65.0, 28.0, and 67.5% respectively. This source can become important only in case of an acute demand for fermentation alcohol.

Process for the fermentative production of acetone, butanol and ethanol

Science.gov (United States)

Glassner, David A.; Jain, Mahendra K.; Datta, Rathin

1991-01-01

A process including multistage continuous fermentation followed by batch fermentation with carefully chosen temperatures for each fermentation step, combined with an asporogenic strain of C. acetobutylicum and a high carbohydrate substrate concentration yields extraordinarily high butanol and total solvents concentrations.

The inhibition of Saccharomyces cerevisiae population during alcoholic fermentation of grape must by octanoic, decanoic and dodecanoic acid mixture

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Baroň Mojmír

2017-01-01

Full Text Available The inhibition of alcoholic fermentation by octanoic, decanoic and dodecanoic acid mixture was investigated. Middle chain fatty acids (MCFA mixture contained 10 grams of C8:C10:C12 in a ratio of 2:7:1 was dissolved in 100 ml of 70% ethanol, and in such form, it was subsequently applied into the fermenting must samples. A flow cytometry test showed that the 10 mg/L dose of MCFA mixture had a toxic effect on Saccharomyces cerevisiae (45.9% of viable cells compared with the control variant (74.35%. In combination with 60 mg/L of SO2, it had a higher efficiency (3.1% of viable cells than using a dose of SO2 alone (13.9%. Direct counting of yeast cells confirmed a higher concentration of dead cells with a higher concentration of MCFA. A dose of 10 mg/L of MCFA mixture caused the highest percentage of dead yeast after 24 hours (about 60% compared to the control variant without MCFA dosage (about 24%. The results of residues showed that there is no significant quantitative difference between the treated and untreated musts because of fixing of MCFA inside the yeast cells. This method can effectively reduce the cost of production technology for wines with residual sugar and, in general, reduce the dosage of SO2.

Metabolic flux analysis during the exponential growth phase of Saccharomyces cerevisiae in wine fermentations.

Directory of Open Access Journals (Sweden)

Manuel Quirós

Full Text Available As a consequence of the increase in global average temperature, grapes with the adequate phenolic and aromatic maturity tend to be overripe by the time of harvest, resulting in increased sugar concentrations and imbalanced C/N ratios in fermenting musts. This fact sets obvious additional hurdles in the challenge of obtaining wines with reduced alcohols levels, a new trend in consumer demands. It would therefore be interesting to understand Saccharomyces cerevisiae physiology during the fermentation of must with these altered characteristics. The present study aims to determine the distribution of metabolic fluxes during the yeast exponential growth phase, when both carbon and nitrogen sources are in excess, using continuous cultures. Two different sugar concentrations were studied under two different winemaking temperature conditions. Although consumption and production rates for key metabolites were severely affected by the different experimental conditions studied, the general distribution of fluxes in central carbon metabolism was basically conserved in all cases. It was also observed that temperature and sugar concentration exerted a higher effect on the pentose phosphate pathway and glycerol formation than on glycolysis and ethanol production. Additionally, nitrogen uptake, both quantitatively and qualitatively, was strongly influenced by environmental conditions. This work provides the most complete stoichiometric model used for Metabolic Flux Analysis of S. cerevisiae in wine fermentations employed so far, including the synthesis and release of relevant aroma compounds and could be used in the design of optimal nitrogen supplementation of wine fermentations.

Fermentation and Characterization of Pitaya Wine

Science.gov (United States)

Gong, Xiao; Yang, Yaxuan; Ma, Lina; Peng, Shaodan; Lin, Mao

2017-12-01

Juice was extracted from pitaya pulp. After fermentation, the wine produced contained 11.2% vol (v/v) alcohol, total sugar content is 7.3g/L, 7.8% °Brix, the content of titratable acid and amino acid nitrogen are 2.34 g/L and 0.46 g/L, respectively. Dragon fruit wine of the communist party of detect aroma components is 56 kinds, content is more than 0.5%, 17 kinds, 9 esters are among those kinds, 5 kinds alcohol, there are 2 kinds of acids, one kind of alkanes. The physicochemical characteristics of wines produced from pitaya is attractive, with unique flavor and rich nutritional value, which makes it widely accepted and even liked.

Enzymes extracted from apple peels have activity in reducing higher alcohols in Chinese liquors.

Science.gov (United States)

Han, Qi'an; Shi, Junling; Zhu, Jing; Lv, Hongliang; Du, Shuangkui

2014-10-01

As the unavoidable byproducts of alcoholic fermentation, higher alcohols are unhealthy compounds widespread in alcoholic drinks. To investigate the activity of apple crude enzymes toward higher alcohols in liquors, five kinds of apple peels, namely, Fuji, Gala, Golden Delicious, Red Star, and Jonagold, were chosen to prepare enzymes, and three kinds of Chinese liquors, namely, Xifeng (containing 45% ethanol), Taibai (containing 50% ethanol), and Erguotou (containing 56% ethanol), were tested. Enzymes were prepared in the forms of liquid solution, powder, and immobilized enzymes using sodium alginate (SA) and chitosan. The treatment was carried out at 37 °C for 1 h. The relative amounts of different alcohols (including ethanol, 1-propanol, isobutanol, 1-butanol, isoamylol, and 1-hexanol) were measured using gas chromatography (GC). Conditions for preparing SA-immobilized Fuji enzymes (SA-IEP) were optimized, and the obtained SA-IEP (containing 0.3 g of enzyme) was continuously used to treat Xifeng liquor eight times, 20 mL per time. Significant degradation rates (DRs) of higher alcohols were observed at different degrees, and it also showed enzyme specificity according to the apple varieties and enzyme preparations. After five repeated treatments, the DRs of the optimized Fuji SA-IEP remained 70% for 1-hexanol and >15% for other higher alcohols.

Saccharomyces cerevisiae KNU5377 stress response during high-temperature ethanol fermentation.

Science.gov (United States)

Kim, Il-Sup; Kim, Young-Saeng; Kim, Hyun; Jin, Ingnyol; Yoon, Ho-Sung

2013-03-01

Fuel ethanol production is far more costly to produce than fossil fuels. There are a number of approaches to cost-effective fuel ethanol production from biomass. We characterized stress response of thermotolerant Saccharomyces cerevisiae KNU5377 during glucose-based batch fermentation at high temperature (40°C). S. cerevisiae KNU5377 (KNU5377) transcription factors (Hsf1, Msn2/4, and Yap1), metabolic enzymes (hexokinase, glyceraldehyde-3-phosphate dehydrogenase, glucose-6-phosphate dehydrogenase, isocitrate dehydrogenase, and alcohol dehydrogenase), antioxidant enzymes (thioredoxin 3, thioredoxin reductase, and porin), and molecular chaperones and its cofactors (Hsp104, Hsp82, Hsp60, Hsp42, Hsp30, Hsp26, Cpr1, Sti1, and Zpr1) are upregulated during fermentation, in comparison to S. cerevisiae S288C (S288C). Expression of glyceraldehyde-3-phosphate dehydrogenase increased significantly in KNU5377 cells. In addition, cellular hydroperoxide and protein oxidation, particularly lipid peroxidation of triosephosphate isomerase, was lower in KNU5377 than in S288C. Thus, KNU5377 activates various cell rescue proteins through transcription activators, improving tolerance and increasing alcohol yield by rapidly responding to fermentation stress through redox homeostasis and proteostasis.

Effects of oxygen limitation on sugar metabolism in yeasts: a continuous-culture study of the Kluyver effect.

Science.gov (United States)

Weusthuis, R A; Visser, W; Pronk, J T; Scheffers, W A; van Dijken, J P

1994-04-01

Growth and metabolite formation were studied in oxygen-limited chemostat cultures of Saccharomyces cerevisiae CBS 8066 and Candida utilis CBS 621 growing on glucose or maltose at a dilution rate of 0.1 h-1. With either glucose or maltose S. cerevisiae could be grown under dual limitation of oxygen and sugar. Respiration and alcoholic fermentation occurred simultaneously and the catabolite fluxes through these processes were dependent on the magnitude of the oxygen feed. C. utilis could also be grown under dual limitation of glucose and oxygen. However, at very low oxygen feed rates (i.e. below 4 mmol l-1 h-1) growth was limited by oxygen only, as indicated by the high residual glucose concentration in the culture. In contrast to S. cerevisiae, C. utilis could not be grown anaerobically at a dilution rate of 0.1 h-1. With C. utilis absence of oxygen resulted in wash-out, despite the presence of ergosterol and Tween-80 in the growth medium. The behaviour of C. utilis with respect to maltose utilization in oxygen-limited cultures was remarkable: alcoholic fermentation did not occur and the amount of maltose metabolized was dependent on the oxygen supply. Oxygen-limited cultures of C. utilis growing on maltose always contained high residual sugar concentrations. These observations throw new light on the so-called Kluyver effect. Apparently, maltose is a non-fermentable sugar for C. utilis CBS 621, despite the fact that it can serve as a substrate for growth of this facultatively fermentative yeast. This is not due to the absence of key enzymes of alcoholic fermentation. Pyruvate decarboxylase and alcohol dehydrogenase were present at high levels in maltose-utilizing cells of C. utilis grown under oxygen limitation. It is concluded that the Kluyver effect, in C. utilis growing on maltose, results from a regulatory mechanism that prevents the sugar from being fermented. Oxygen is not a key factor in this phenomenon since under oxygen limitation alcoholic fermentation of

Fermentation of solid wastes in Switzerland; Feststoff-Vergaerung in der Schweiz. Schlussbericht 2007

Energy Technology Data Exchange (ETDEWEB)

Liesch, B.; Mueller, C.

2007-06-15

This final report for the Swiss Federal Office of Energy (SFOE) presents the results of a study on dry fermentation technologies. Information on the state-of-the-art of current dry fermentation systems is presented and the potential of implementing dry fermentation in Swiss agriculture is discussed. The study reveals that the current dry fermentation technologies provided by various enterprises are partly not suitable (complex, continuous operating digestion reactors, developed for handling municipal solid waste). Batch digestion reactors, however, are said by the authors to be mature for application in the Swiss agricultural area. Wet fermentation technologies are also quoted as being able to utilise organic substrates with high dry-matter content and are thus said to be economically more competitive than dry fermentation systems. Dry fermentation is quoted as being a technology with a high development potential. Details are presented on several continuous and non-continuous processes used. Also, the potential for the fermentation of solid wastes in Switzerland is reviewed. Experience made in Germany is also examined.

Characteristics of Milk Fermented by Streptococcus thermophilus MGA45-4 and the Profiles of Associated Volatile Compounds during Fermentation and Storage

Directory of Open Access Journals (Sweden)

Tong Dan

2018-04-01

Full Text Available The lactic acid bacterium Streptococcus thermophilus is a major starter culture for the production of dairy products. In this study, the physiochemical characteristics of milk fermented by the MGA45-4 isolate of S. thermophilus were analyzed. Our data indicate that milk fermented using S. thermophilus MGA45-4 maintained a high viable cell count (8.86 log10 colony-forming units/mL, and a relatively high pH (4.4, viscosity (834.33 mPa·s, and water holding capacity (40.85% during 14 days of storage. By analyzing the volatile compound profile using solid-phase microextraction and gas chromatography/mass spectrometry, we identified 73 volatile compounds in the fermented milk product, including five carboxylic acids, 21 aldehydes, 13 ketones, 16 alcohols, five esters, and 13 aromatic carbohydrates. According to the odor activity values, 11 of these volatile compounds were found to play a key role in producing the characteristic flavor of fermented milk, particularly octanal, nonanal, hexanal, 2,3-butanedione, and 1-octen-3-ol, which had the highest odor activity values among all compounds analyzed. These findings thus provide more insights in the chemical/molecular characteristics of milk fermented using S. thermophilus, which may provide a basis for improving dairy product flavor/odor during the process of fermentation and storage.

Microorganisms in Fermented Apple Beverages: Current Knowledge and Future Directions.

Science.gov (United States)

Cousin, Fabien J; Le Guellec, Rozenn; Schlusselhuber, Margot; Dalmasso, Marion; Laplace, Jean-Marie; Cretenet, Marina

2017-07-25

Production of fermented apple beverages is spread all around the world with specificities in each country. 'French ciders' refer to fermented apple juice mainly produced in the northwest of France and often associated with short periods of consumption. Research articles on this kind of product are scarce compared to wine, especially on phenomena associated with microbial activities. The wine fermentation microbiome and its dynamics, organoleptic improvement for healthy and pleasant products and development of starters are now widely studied. Even if both beverages seem close in terms of microbiome and process (with both alcoholic and malolactic fermentations), the inherent properties of the raw materials and different production and environmental parameters make research on the specificities of apple fermentation beverages worthwhile. This review summarizes current knowledge on the cider microbial ecosystem, associated activities and the influence of process parameters. In addition, available data on cider quality and safety is reviewed. Finally, we focus on the future role of lactic acid bacteria and yeasts in the development of even better or new beverages made from apples.

Molasses and grains together (in alcohol production)

Energy Technology Data Exchange (ETDEWEB)

Malchenko, A L; Poluyanova, M T

1961-01-01

The simultaneous fermentation of mashes prepared from grains and molasses is entirely feasible. It is preferable to run the fermentation continuously in this case, starting with a grain fermentation liquor containing little molasses. As time progresses more and more molasses are added to replace the fermented sugar.

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)

2008-01-01

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.

Formaldehyde as an antiseptic in the production of alcohol from molasses

Energy Technology Data Exchange (ETDEWEB)

Rosa, M; Vernerova, J; Stros, F

1962-01-01

The effect of formaldehyde as an antiseptic for the noncontaminated alcohol fermentation of molasses was examined with five different yeast-mash batches containing formaldehyde 0.01%. Following 24 hour cultivation, increase in the activity of formaldehyde-inoculated mash was lowered by 47%; the formaldehyde decreased the alcohol fermentation and lessened the rate of fermentation of sugar by 20% in noncontaminated mash. The decrease in the fermentation rate was also observed during the entire course of fermentation. On the other hand, formaldehyde addition to molasses contaminated with lactic acid bacteria accelerated the fermentation rate by inhibiting the bacterial growth; the degree of retardation due to the contamination was greater than that due to the antiseptic. The view that formaldehyde decreased the effectiveness of growth substances by binding the amino acid present in mash mixtures could not be confirmed; it was believed that formaldehyde was absorbed by yeast cells even through the entities thus destroyed could not be differentiated from living cells by methylene blue. Higher resistance of yeast cultures to formaldehyde was obtained by repeated transfers of the yeast in media containing formaldehyde. It was concluded that formaldehyde added to contaminated molasses inhibited the further growth of the contamination, increased yield of ethanol on the basis of the sugar, and simultaneously decreased the net yield of ethanol in contrast to the yield from noncontaminated mashes in the absence of formaldehyde.

Increasing the yeast yield in alcohol fermentation

Energy Technology Data Exchange (ETDEWEB)

Pelc, A; Vamos, E; Varga, L; Gavalya, S; Dolanszky, F

1964-02-01

The yeast and ethanol yields (the latter being based on the substrate) are enhanced by adding the substrate (molasses) gradually to the suspension of inoculating yeast during the main fermentation period, passing air through the mash, ceasing both substrate addition and aeration at the end of the main period, and allowing the process to come to an end. This way 12 to 14 kg yeast (dry weight)/100 l ethanol could be obtained within 16 to 24 hours and the yeast obtained could be used as the inoculum for the next charge. For example: 11 to 16 kg yeast (or 18 to 25 l yeast suspension from the preceding charge, containing 18 to 20% dry matter) is kept in 30 to 35 l H/sub 2/SO/sub 4/ (0.74 g/100 ml) for 1 hour, diluted with H/sub 2/O and 30 kg sterile molasses to 300 l, kept at 30 to 32/sup 0/ with mild aeration for 2 hours, 1900 l 30/sup 0/ H/sub 2/O added, then 1 m/sup 3/ air/m/sup 2//hour is passed through the mixture, with the addition of 270 kg sterile molasses, and a solution of 8 kg superphosphate and 5 kg (NH/sub 4/)/sub 2/SO/sub 4/ in 100 l H/sub 2/O, the latter being added in 5 portions over 2 hours. Molasses (600 kg) is added during the main period, maintaining the pH at 5 (H/sub 2/SO/sub 4/), and the temperature at 30/sup 0/, then aeration is ceased and the mixture kept until fermentation proceeds. The 3000 l medium contains 9.6% ethanol and 1.38% yeast, respectively.