scholarly journals Analysis of Lipid Compositional Changes During Alcoholic Fermentation in Industrial Yeast Strains with Varying Ethanol Tolerance

2010 ◽  
Vol 98 (3) ◽  
pp. 607a
Author(s):  
Clark M. Henderson ◽  
David E. Block ◽  
Marjorie L. Longo
Keyword(s):  
Alcoholic Fermentation ◽  
Ethanol Tolerance ◽  
Industrial Yeast ◽  
Yeast Strains ◽  
Compositional Changes

scholarly journals Oenological Potential of Autochthonous Saccharomyces cerevisiae Yeast Strains from the Greek Varieties of Agiorgitiko and Moschofilero

Beverages ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 27
Author(s):  
Dimitrios Kontogiannatos ◽  
Vicky Troianou ◽  
Maria Dimopoulou ◽  
Polydefkis Hatzopoulos ◽  
Yorgos Kotseridis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Alcoholic Fermentation ◽  
Ethanol Tolerance ◽  
Random Amplified Polymorphic Dna ◽  
Yeast Strains ◽  
Rapd Pcr ◽  
Autochthonous Yeast ◽  
Polymerase Chain ◽  
Grape Varieties ◽  
H2s Production

Nemea and Mantinia are famous wine regions in Greece known for two indigenous grape varieties, Agiorgitiko and Moschofilero, which produce high quality PDO wines. In the present study, indigenous Saccharomyces cerevisiae yeast strains were isolated and identified from spontaneous alcoholic fermentation of Agiorgitiko and Moschofilero musts in order to evaluate their oenological potential. Random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) recovered the presence of five distinct profiles from a total of 430 yeast isolates. The five obtained strains were evaluated at microvinifications trials and tested for basic oenological and biochemical parameters including sulphur dioxide and ethanol tolerance as well as H2S production in sterile grape must. The selected autochthonous yeast strains named, Soi2 (Agiorgitiko wine) and L2M (Moschofilero wine), were evaluated also in industrial (4000L) fermentations to assess their sensorial and oenological characteristics. The volatile compounds of the produced wines were determined by GC-FID. Our results demonstrated the feasibility of using Soi2 and L2M strains in industrial fermentations for Agiorgitiko and Moschofilero grape musts, respectively.

scholarly journals Vacuolar H+-ATPase Protects Saccharomyces cerevisiae Cells against Ethanol-Induced Oxidative and Cell Wall Stresses

2016 ◽  
Vol 82 (10) ◽  
pp. 3121-3130 ◽  
Author(s):  
Sirikarn Charoenbhakdi ◽  
Thanittra Dokpikul ◽  
Thanawat Burphan ◽  
Todsapol Techo ◽  
Choowong Auesukaree
Keyword(s):  
Cell Wall ◽  
Alcoholic Fermentation ◽  
Ethanol Tolerance ◽  
Wall Stress ◽  
Yeast Cells ◽  
Intracellular Acidification ◽  
Straight Chain ◽  
Cell Wall Stress ◽  
Yeast Strains ◽  
Vacuolar Acidification

ABSTRACTDuring fermentation, increased ethanol concentration is a major stress for yeast cells. Vacuolar H+-ATPase (V-ATPase), which plays an important role in the maintenance of intracellular pH homeostasis through vacuolar acidification, has been shown to be required for tolerance to straight-chain alcohols, including ethanol. Since ethanol is known to increase membrane permeability to protons, which then promotes intracellular acidification, it is possible that the V-ATPase is required for recovery from alcohol-induced intracellular acidification. In this study, we show that the effects of straight-chain alcohols on membrane permeabilization and acidification of the cytosol and vacuole are strongly dependent on their lipophilicity. These findings suggest that the membrane-permeabilizing effect of straight-chain alcohols induces cytosolic and vacuolar acidification in a lipophilicity-dependent manner. Surprisingly, after ethanol challenge, the cytosolic pH in Δvma2and Δvma3mutants lacking V-ATPase activity was similar to that of the wild-type strain. It is therefore unlikely that the ethanol-sensitive phenotype ofvmamutants resulted from severe cytosolic acidification. Interestingly, thevmamutants exposed to ethanol exhibited a delay in cell wall remodeling and a significant increase in intracellular reactive oxygen species (ROS). These findings suggest a role for V-ATPase in the regulation of the cell wall stress response and the prevention of endogenous oxidative stress in response to ethanol.IMPORTANCEThe yeastSaccharomyces cerevisiaehas been widely used in the alcoholic fermentation industry. Among the environmental stresses that yeast cells encounter during the process of alcoholic fermentation, ethanol is a major stress factor that inhibits yeast growth and viability, eventually leading to fermentation arrest. This study provides evidence for the molecular mechanisms of ethanol tolerance, which is a desirable characteristic for yeast strains used in alcoholic fermentation. The results revealed that straight-chain alcohols induced cytosolic and vacuolar acidification through their membrane-permeabilizing effects. Contrary to expectations, a role for V-ATPase in the regulation of the cell wall stress response and the prevention of endogenous oxidative stress, but not in the maintenance of intracellular pH, seems to be important for protecting yeast cells against ethanol stress. These findings will expand our understanding of the mechanisms of ethanol tolerance and provide promising clues for the development of ethanol-tolerant yeast strains.

scholarly journals Recombinant Diploid Saccharomyces cerevisiae Strain Development for Rapid Glucose and Xylose Co-Fermentation

Fermentation ◽  
2018 ◽  
Vol 4 (3) ◽  
pp. 59 ◽  
Author(s):  
Tingting Liu ◽  
Shuangcheng Huang ◽  
Anli Geng
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Alcoholic Fermentation ◽  
Ethanol Yield ◽  
Xylose Isomerase ◽  
Cost Effective ◽  
Xylose Utilization ◽  
Yeast Strains ◽  
Multiple Copies ◽  
Biomass Sugars ◽  
Sugar Conversion

Cost-effective production of cellulosic ethanol requires robust microorganisms for rapid co-fermentation of glucose and xylose. This study aims to develop a recombinant diploid xylose-fermenting Saccharomyces cerevisiae strain for efficient conversion of lignocellulosic biomass sugars to ethanol. Episomal plasmids harboring codon-optimized Piromyces sp. E2 xylose isomerase (PirXylA) and Orpinomyces sp. ukk1 xylose (OrpXylA) genes were constructed and transformed into S. cerevisiae. The strain harboring plasmids with tandem PirXylA was favorable for xylose utilization when xylose was used as the sole carbon source, while the strain harboring plasmids with tandem OrpXylA was beneficial for glucose and xylose cofermentation. PirXylA and OrpXylA genes were also individually integrated into the genome of yeast strains in multiple copies. Such integration was beneficial for xylose alcoholic fermentation. The respiration-deficient strain carrying episomal or integrated OrpXylA genes exhibited the best performance for glucose and xylose co-fermentation. This was partly attributed to the high expression levels and activities of xylose isomerase. Mating a respiration-efficient strain carrying the integrated PirXylA gene with a respiration-deficient strain harboring integrated OrpXylA generated a diploid recombinant xylose-fermenting yeast strain STXQ with enhanced cell growth and xylose fermentation. Co-fermentation of 162 g L−1 glucose and 95 g L−1 xylose generated 120.6 g L−1 ethanol in 23 h, with sugar conversion higher than 99%, ethanol yield of 0.47 g g−1, and ethanol productivity of 5.26 g L−1·h−1.

scholarly journals Rapid Colorimetric Detection of Genome Evolution in SCRaMbLEd Synthetic Saccharomyces cerevisiae Strains

2020 ◽  
Vol 8 (12) ◽  
pp. 1914
Author(s):  
Elizabeth L. I. Wightman ◽  
Heinrich Kroukamp ◽  
Isak S. Pretorius ◽  
Ian T. Paulsen ◽  
Helena K. M. Nevalainen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Genome Evolution ◽  
Colorimetric Detection ◽  
Cre Recombinase ◽  
Control Measures ◽  
Genomic Rearrangements ◽  
Industrial Yeast ◽  
Poor Growth ◽  
Yeast Strains ◽  
Industrial Strains

Genome-scale engineering and custom synthetic genomes are reshaping the next generation of industrial yeast strains. The Cre-recombinase-mediated chromosomal rearrangement mechanism of designer synthetic Saccharomyces cerevisiae chromosomes, known as SCRaMbLE, is a powerful tool which allows rapid genome evolution upon command. This system is able to generate millions of novel genomes with potential valuable phenotypes, but the excessive loss of essential genes often results in poor growth or even the death of cells with useful phenotypes. In this study we expanded the versatility of SCRaMbLE to industrial strains, and evaluated different control measures to optimize genomic rearrangement, whilst limiting cell death. To achieve this, we have developed RED (rapid evolution detection), a simple colorimetric plate-assay procedure to rapidly quantify the degree of genomic rearrangements within a post-SCRaMbLE yeast population. RED-enabled semi-synthetic strains were mated with the haploid progeny of industrial yeast strains to produce stress-tolerant heterozygous diploid strains. Analysis of these heterozygous strains with the RED-assay, genome sequencing and custom bioinformatics scripts demonstrated a correlation between RED-assay frequencies and physical genomic rearrangements. Here we show that RED is a fast and effective method to evaluate the optimal SCRaMbLE induction times of different Cre-recombinase expression systems for the development of industrial strains.

Influence of various yeast strains and selected starchy raw materials on production of higher alcohols during the alcoholic fermentation process

2014 ◽  
Vol 240 (1) ◽  
pp. 233-242 ◽  
Author(s):  
Grzegorz Kłosowski ◽  
Dawid Mikulski ◽  
Dorota Macko ◽  
Beata Miklaszewska ◽  
Katarzyna Kotarska ◽  
...  
Keyword(s):  
Fermentation Process ◽  
Alcoholic Fermentation ◽  
Raw Materials ◽  
Higher Alcohols ◽  
Yeast Strains

scholarly journals Isolation of Auxotrophic Mutants of Diploid Industrial Yeast Strains after UV Mutagenesis

2005 ◽  
Vol 71 (1) ◽  
pp. 312-319 ◽  
Author(s):  
Shinji Hashimoto ◽  
Mayumi Ogura ◽  
Kazuo Aritomi ◽  
Hisashi Hoshida ◽  
Yoshinori Nishizawa ◽  
...  
Keyword(s):  
Selection Procedure ◽  
Isoamyl Acetate ◽  
Gene Replacement ◽  
Industrial Yeast ◽  
Uv Mutagenesis ◽  
Mutant Selection ◽  
Auxotrophic Mutants ◽  
Recessive Mutations ◽  
Alcohol Acetyltransferase ◽  
Yeast Strains

ABSTRACT Auxotrophic mutants of the yeast Saccharomyces cerevisiae are usually isolated in haploid strains because the isolation of recessive mutations in diploids is thought to be difficult due to the presence of two sets of genes. We show here that auxotrophic mutants of diploid industrial sake yeast strains were routinely obtained by a standard mutant selection procedure following UV mutagenesis. We isolated His−, Met−, Lys−, Trp−, Leu−, Arg−, and Ura− auxotrophic mutants of five sake strains, Kyokai no. 7, no. 9, no. 10, no. 701, and no. 901, by screening only 1,700 to 3,400 colonies from each treated strain. Wild-type alleles were cloned and used as markers for transformation. With HIS3 as a selectable marker, the yeast TDH3 overexpression promoter was inserted upstream of ATF1, encoding alcohol acetyltransferase, by one-step gene replacement in a his3 mutant of Kyokai no. 7. The resulting strain contained exclusively yeast DNA, making it acceptable for commercial use, and produced a larger amount of isoamyl acetate, a banana-like flavor. We argue that the generally recognized difficulty of isolating auxotrophic mutants of diploid industrial yeast strains is misleading and that genetic techniques used for haploid laboratory strains are applicable for this purpose.

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