scholarly journals EFFECT OF CULTURAL CONDITION ON PRODUCTION OF ETHANOL FROM ROTTEN APPLE WASTE BY SACCHAROMYCES CEREVISIAE STRAINING

2012 ◽  
Vol 2 ◽  
pp. 12-21
Author(s):  
Arifa Tahir ◽  

The present study describes the ethanol fermentation from apple waste by locally isolated yeast strain. Fifteen yeast strains were isolated from soil and apples. The culture with maximum ethanol production (8.3%) was identified and designated as Saccharomyces cerevisiae LCY-08

Author(s):  
Hiroaki Negoro ◽  
Atsushi Kotaka ◽  
Hiroki Ishida

ABSTRACT Saccharomyces cerevisiae produces organic acids including malate during alcohol fermentation. Since malate contributes to the pleasant flavor of sake, high-malate-producing yeast strain No. 28 and No. 77 have been developed by the Brewing Society of Japan. In this study, the genes responsible for the high malate phenotype in these strains were investigated. We had found previously that the deletion of components of the glucose induced degradation-deficient (GID) complex led to high malate production in yeast. Upon examining GID protein-coding genes in yeast strain No. 28 and No. 77, a nonsense homozygous mutation of GID4 in strain No. 28, and of GID2 in strain No. 77, were identified as the cause of high malate production. Furthermore, complementary tests of these mutations indicated that the heterozygous nonsense mutation in GID2 was recessive. In contrast, the heterozygous nonsense mutation in GID4 was considered semi-dominant.


2017 ◽  
Vol 83 (20) ◽  
Author(s):  
Bruna Inez Carvalho Figueiredo ◽  
Margarete Alice Fontes Saraiva ◽  
Paloma Patrick de Souza Pimenta ◽  
Miriam Conceição de Souza Testasicca ◽  
Geraldo Magela Santos Sampaio ◽  
...  

ABSTRACT The development of hybrids has been an effective approach to generate novel yeast strains with optimal technological profile for use in beer production. This study describes the generation of a new yeast strain for lager beer production by direct mating between two Saccharomyces cerevisiae strains isolated from cachaça distilleries: one that was strongly flocculent, and the other with higher production of acetate esters. The first step in this procedure was to analyze the sporulation ability and reproductive cycle of strains belonging to a specific collection of yeasts isolated from cachaça fermentation vats. Most strains showed high rates of sporulation, spore viability, and homothallic behavior. In order to obtain new yeast strains with desirable properties useful for lager beer production, we compare haploid-to-haploid and diploid-to-diploid mating procedures. Moreover, an assessment of parental phenotype traits showed that the segregant diploid C2-1d generated from a diploid-to-diploid mating experiment showed good fermentation performance at low temperature, high flocculation capacity, and desirable production of acetate esters that was significantly better than that of one type lager strain. Therefore, strain C2-1d might be an important candidate for the production of lager beer, with distinct fruit traces and originating using a non-genetically modified organism (GMO) approach. IMPORTANCE Recent work has suggested the utilization of hybridization techniques for the generation of novel non-genetically modified brewing yeast strains with combined properties not commonly found in a unique yeast strain. We have observed remarkable traits, especially low temperature tolerance, maltotriose utilization, flocculation ability, and production of volatile aroma compounds, among a collection of Saccharomyces cerevisiae strains isolated from cachaça distilleries, which allow their utilization in the production of beer. The significance of our research is in the use of breeding/hybridization techniques to generate yeast strains that would be appropriate for producing new lager beers by exploring the capacity of cachaça yeast strains to flocculate and to ferment maltose at low temperature, with the concomitant production of flavoring compounds.


Author(s):  
José Duarte ◽  
Vera Lourenço ◽  
Belina Ribeiro ◽  
Maria Céu Saagua ◽  
Joana Pereira ◽  
...  

During the last years there has been an increasing interest in using ethanol as a substitute for fossil fuels. The bioethanol used today is mainly produced from sugar cane and cereals, but reducing the production costs of ethanol is still crucial for a viable economic process. Cellulose from vegetable biomass will be the next cheap raw material for second generation fuel ethanol production and agricultural by-products with a low commercial value, as corn stover, corn fiber and cane bagasses would become an attractive feedstock for bioethanol production.In this study, different strains of Saccharomyces cerevisiae have been screened for the ability of bioethanol production. Yeasts were grown in a synthetic liquid medium containing sucrose in batch regime and the growth rates, ethanol and biomass productions were determined as well as their growth ability in cane molasses.The results indicate that a flocculent yeast, isolated in our lab and designated by strain F, was the most promising yeast strain among those tested for continuous ethanol production. This strain was isolated from corn hydrolysates, obtained from a Portuguese distillery facility (DVT, Torres Novas, Portugal) showing highest growth rate (0.49h-1), highest ethanol yield (0.35g/g) and high flocculation capacity.The study on ethanol production in continuous reactor process with the selected yeast strain (strain F) was made on sucrose and cane molasses at different dilution rates (0.05-0.42 h-1). A steady flocculating yeast fluidized bed reactor system was established allowing the functioning of the reactor for 1000 h. Data shows that when the dilution rate rose to 0.42h-1, the highest productivity (20g/Lh) was obtained attaining an ethanol concentration in the reactor of 47g/L for sucrose and molasses media.


2021 ◽  
Author(s):  
Kevy Pontes Eliodório ◽  
Gabriel Caetano de Gois e Cunha ◽  
Brianna A White ◽  
Demisha HM Patel ◽  
Fangyi Zhang ◽  
...  

Ethanol fermentation is frequently performed under conditions of low nitrogen. In Saccharomyces cerevisiae, nitrogen limitation induces macroautophagy, including the selective removal of mitochondria, also called mitophagy. Shiroma and co-workers (2014) showed that blocking mitophagy by deletion of the mitophagy specific gene ATG32 increased the fermentation performance during the brewing of Ginjo sake. In this study, we tested if a similar strategy could enhance alcoholic fermentation in the context of fuel ethanol production from sugarcane in Brazilian biorefineries. Conditions that mimic the industrial fermentation process indeed induce Atg32-dependent mitophagy in cells of S. cerevisiae PE-2, a strain frequently used in the industry. However, after blocking mitophagy, no differences in CO2production, final ethanol titres or cell viability were observed after five rounds of ethanol fermentation, cell recycling and acid treatment, as commonly performed in sugarcane biorefineries. To test if S. cerevisiae's strain background influences this outcome, cultivations were carried out in a synthetic medium with strains PE-2, Ethanol Red (industrial) and BY (laboratory), with and without a functional ATG32 gene, under oxic and oxygen restricted conditions. Despite the clear differences in sugar consumption, cell viability and ethanol titres, among the three strains, we could not observe any improvement in fermentation performance related to the blocking of mitophagy. We conclude with caution that results obtained with Ginjo sake yeast is an exception and cannot be extrapolated to other yeast strains and that more research is needed to ascertain the role of autophagic processes during fermentation.


2020 ◽  
Vol 42 ◽  
pp. e43427
Author(s):  
Mayara Vieira Santos ◽  
Adriana Régia Marques Souza ◽  
Maria Carolina Santos Silva ◽  
Gabriel Luis Castiglioni

In the Brazilian industries, the inoculum used throughout the harvest of ethanol production consists of a combination of two or more yeast strains. The combination of yeasts may influence in the metabolic pathways of microorganisms and increase the yields and production rates of some compounds. In biotechnological processes with co-culture, one microorganism can prevail over the other. Therefore, the knowledge about how the population dynamics occurs during fermentation allows modifications in the process in order to obtain higher yields and to achieve greater fermentative efficiency. The aim of this study was to investigate the fermentation with synthetic sugar cane broth in co-culture of Saccharomyces cerevisiae strains CAT-1 and PE-2 followed by molecular fermentation monitoring. The concentration of biomass, ethanol, glycerol, acetic acid and residual sucrose were monitored to verify the influence of different combinations during the fermentation. The mixture of CAT-1 and PE-2 presented the highest ethanol production, with higher performance of fermentative parameters than pure cultures


2001 ◽  
Vol 67 (9) ◽  
pp. 4346-4348 ◽  
Author(s):  
Vincent J. Higgins ◽  
Philip J. L. Bell ◽  
Ian W. Dawes ◽  
Paul V. Attfield

ABSTRACT A yeast strain capable of leavening both unsugared and sweet bread dough efficiently would reduce the necessity of carrying out the expensive procedure of producing multiple baker's yeast strains. But issues involving the use of genetically modified foods have rendered the use of recombinant techniques for developing yeast strains controversial. Therefore, we used strong selection and screening systems in conjunction with traditional mass mating techniques to develop a strain of Saccharomyces cerevisiaethat efficiently leavens both types of dough.


Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4519
Author(s):  
Brandon Whitmore ◽  
Stephanie McCann ◽  
Matthew Noestheden ◽  
Eric Dennis ◽  
Sarah Lyons ◽  
...  

When wine grapes are exposed to smoke, there is a risk that the resulting wines may possess smoky, ashy, or burnt aromas, a wine flaw known as smoke taint. Smoke taint occurs when the volatile phenols (VPs) largely responsible for the aroma of smoke are transformed in grape into a range of glycosides that are imperceptible by smell. The majority of VP-glycosides described to date are disaccharides possessing a reducing β-d-glucopyranosyl moiety. Here, a two-part experiment was performed to (1) assess the stability of 11 synthesized VP-glycosides towards general acid-catalyzed hydrolysis during aging, and (2) to examine whether yeast strains differed in their capacity to produce free VPs both from these model glycosides as well as from grapes that had been deliberately exposed to smoke. When fortified into both model and real wine matrices at 200 ng/g, all VP-disaccharides were stable over 12 weeks, while (42–50 ng/g) increases in free 4-ethylphenol and p-cresol were detected when these were added to wine as their monoglucosides. Guaiacol and phenol were the most abundantly produced VPs during fermentation, whether originating from natural VP-precursors in smoked-exposed Pinot Noir must, or due to fortification with synthetic VP-glycosides. Significant yeast strain-specific differences in glycolytic activities were observed for phenyl-β-d-glycopyranoside, with two strains (RC212 and BM45) being unable to hydrolyze this model VP, albeit both were active on the guaiacyl analogue. Thus, differences in Saccharomyces cerevisiae β-glucosidase activity appear to be influenced by the VP moiety.


2020 ◽  
Author(s):  
Jarina Joshi ◽  
Tribikram Bhattarai ◽  
Amar Yadav ◽  
Lakshmaiah Sreer

Abstract Yeasts are the mainstay in ethanol production industry. Search for efficient yeast strains that are salt tolerant and utilize both hexoses (glucose) and pentoses (xylose and arabinose) is important in fermentation industry. In this regard,12 yeast strains, viz., CDBT1-12, were isolated from various sources and characterized. Molecular characterization of the yeast strains was done by sequencing 26S rRNA gene, D1D2 region. Out of 12 isolates, 10 were found to be Saccharomyces cerevisiae , CDBT7 was Wikerhamomyces anomalous , and CDBT8 was Cyberlindnera fabianii . The yeast isolates were characterized in terms of their ethanol production efficiency, salt tolerance and ability to utilize of glucose and xylose. All the strains were found to be good ethanol producers. Yeast strain CDBT2 was found to have tolerance for high salt (up to 15%) and ethanol (up to 16%) concentrations. Yeast strain CDBT7 was found to utilize both glucose and xylose without compromising on ethanol production efficiency. The CDBT7 strain was also salt tolerant (up to15%).Yeast strain CDBT2 when grown in an electrochemical cell with low levels of applied external voltage, alcohol dehydrogenase (ADH1) and pyruvate decarboxylase (PDC1) mRNA levels were increased by 2.78 ± 0.80 and 1.12 ± 0.37 fold, respectively. We believe, the latter observation is novel and it has not been reported previously. It also further supports our previous observation of increase in level of alcohol production by CDBT2 strain in the presence of applied electrical current.


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