scholarly journals INHIBITION OF THE GROWTH OF TOLERANT YEAST Saccharomyces cerevisiae STRAIN I136 BY A MIXTURE OF SYNTHETIC INHIBITORS

2017 ◽  
Vol 18 (1) ◽  
pp. 17
Author(s):  
Eny Ida Riyanti ◽  
Edy Listanto
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acetic Acid ◽  
Carbon Sources ◽  
Resistance Mechanism ◽  
Lag Phase ◽  
Cell Factory ◽  
Yeast Saccharomyces Cerevisiae ◽  
Fermentation Products ◽  
Hydroxymethyl Furfural ◽  
Cell Biomass

<p>Biomass from lignocellulosic wastes is a potential source for biobased products.  However, one of the constraints in utilization of biomass hydrolysate is the presence of inhibitors. Therefore, the use of inhibitor-tolerant microorganisms in the fermentation is required. The study aimed to investigate the effect of a mixture of inhibitors on the growth of Saccharomyces cerevisiae strain I136 grown in medium containing synthetic inhibitors (acetic acid, formic acid, furfural, 5-hydroxymethyl furfural/5-HMF, and levulinic acid) in four different concentrations with a mixture of carbon sources, glucose  (50 g.l-1) and xylose (50 g.l-1) at 30oC. The parameters related to growth and fermentation products were observed. Results showed that the strain was able to grow in media containing natural inhibitors (BSL medium) with µmax of 0.020/h. Higher level of synthetic inhibitors prolonged the lag phase, decreased the cell biomass and ethanol production, and specific growth rate. The strain could detoxify furfural and 5-HMF and produced the highest ethanol (Y(p/s) of 0.32 g.g-1) when grown in BSL. Glucose was utilized as its level decreased in a result of increase in cell biomass, in contrast to xylose which was not consumed. The highest cell biomass was produced in YNB with Y (x/s) value of 0.25 g.g-1. The strain produced acetic acid as a dominant side product and could convert furfural into a less toxic compound, hydroxyl furfural. This robust tolerant strain provides basic information on resistance mechanism and would be useful for bio-based cell factory using lignocellulosic materials. </p>

scholarly journals Improvement of inhibitor tolerance in Saccharomyces cerevisiae by overexpression of the quinone oxidoreductase family gene YCR102C

2019 ◽  
Vol 19 (6) ◽  
Author(s):  
Hongqi Chen ◽  
Jie Li ◽  
Chun Wan ◽  
Qing Fang ◽  
Fengwu Bai ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acetic Acid ◽  
Acid Stress ◽  
Acid Tolerance ◽  
Cell Factory ◽  
Quinone Oxidoreductase ◽  
Yeast Saccharomyces Cerevisiae ◽  
Inhibitor Tolerance ◽  
Family Gene ◽  
Novel Strategy

ABSTRACT Budding yeast Saccharomyces cerevisiae is widely used for lignocellulosic biorefinery. However, its fermentation efficiency is challenged by various inhibitors (e.g. weak acids, furfural) in the lignocellulosic hydrolysate, and acetic acid is commonly present as a major inhibitor. The effects of oxidoreductases on the inhibitor tolerance of S. cerevisiae have mainly focused on furfural and vanillin, whereas the influence of quinone oxidoreductase on acetic acid tolerance is still unknown. In this study, we show that overexpression of a quinone oxidoreductase-encoding gene, YCR102C, in S. cerevisiae, significantly enhanced ethanol production under acetic acid stress as well as in the inhibitor mixture, and also improved resistance to simultaneous stress of 40°C and 3.6 g/L acetic acid. Increased catalase activities, NADH/NAD+ ratio and contents of several metals, especially potassium, were observed by YCR102C overexpression under acetic acid stress. To our knowledge, this is the first report that the quinone oxidoreductase family protein is related to acid stress tolerance. Our study provides a novel strategy to increase lignocellulosic biorefinery efficiency using yeast cell factory.

scholarly journals Saccharomyces cerevisiae Fermentation of 28 Barley and 12 Oat Cultivars

Fermentation ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 59
Author(s):  
Timothy J. Tse ◽  
Daniel J. Wiens ◽  
Jianheng Shen ◽  
Aaron D. Beattie ◽  
Martin J. T. Reaney
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Succinic Acid ◽  
Alcoholic Fermentation ◽  
Ethanol Yield ◽  
Cereal Crops ◽  
Fermentation Products ◽  
Barley Cultivars ◽  
Oat Cultivars

As barley and oat production have recently increased in Canada, it has become prudent to investigate these cereal crops as potential feedstocks for alcoholic fermentation. Ethanol and other coproduct yields can vary substantially among fermented feedstocks, which currently consist primarily of wheat and corn. In this study, the liquified mash of milled grains from 28 barley (hulled and hull-less) and 12 oat cultivars were fermented with Saccharomyces cerevisiae to determine concentrations of fermentation products (ethanol, isopropanol, acetic acid, lactic acid, succinic acid, α-glycerylphosphorylcholine (α-GPC), and glycerol). On average, the fermentation of barley produced significantly higher amounts of ethanol, isopropanol, acetic acid, succinic acid, α-GPC, and glycerol than that of oats. The best performing barley cultivars were able to produce up to 78.48 g/L (CDC Clear) ethanol and 1.81 g/L α-GPC (CDC Cowboy). Furthermore, the presence of milled hulls did not impact ethanol yield amongst barley cultivars. Due to its superior ethanol yield compared to oats, barley is a suitable feedstock for ethanol production. In addition, the accumulation of α-GPC could add considerable value to the fermentation of these cereal crops.

scholarly journals Maintenance of Mitochondrial Morphology Is Linked to Maintenance of the Mitochondrial Genome in Saccharomyces cerevisiae

Genetics ◽  
2002 ◽  
Vol 162 (3) ◽  
pp. 1147-1156 ◽  
Author(s):  
Theodor Hanekamp ◽  
Mary K Thorsness ◽  
Indrani Rebbapragada ◽  
Elizabeth M Fisher ◽  
Corrine Seebart ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Growth Rate ◽  
Mitochondrial Dna ◽  
Carbon Sources ◽  
Mitochondrial Morphology ◽  
Yeast Saccharomyces Cerevisiae ◽  
Slow Growth Rate ◽  
Dna Migration ◽  
Mitochondrial Dna Stability ◽  
Extragenic Suppressors

Abstract In the yeast Saccharomyces cerevisiae, certain mutant alleles of YME4, YME6, and MDM10 cause an increased rate of mitochondrial DNA migration to the nucleus, carbon-source-dependent alterations in mitochondrial morphology, and increased rates of mitochondrial DNA loss. While single mutants grow on media requiring mitochondrial respiration, any pairwise combination of these mutations causes a respiratory-deficient phenotype. This double-mutant phenotype allowed cloning of YME6, which is identical to MMM1 and encodes an outer mitochondrial membrane protein essential for maintaining normal mitochondrial morphology. Yeast strains bearing null mutations of MMM1 have altered mitochondrial morphology and a slow growth rate on all carbon sources and quantitatively lack mitochondrial DNA. Extragenic suppressors of MMM1 deletion mutants partially restore mitochondrial morphology to the wild-type state and have a corresponding increase in growth rate and mitochondrial DNA stability. A dominant suppressor also suppresses the phenotypes caused by a point mutation in MMM1, as well as by specific mutations in YME4 and MDM10.

The Cloning and Mapping of ADR6, a Gene Required for Sporulation and for Expression of the Alcohol Dehydrogenase II Isozyme From Saccharomyces cerevisiae

Genetics ◽  
1987 ◽  
Vol 116 (4) ◽  
pp. 531-540
Author(s):  
Aileen K W Taguchi ◽  
Elton T Young
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Alcohol Dehydrogenase ◽  
Single Gene ◽  
Carbon Sources ◽  
Transcription Unit ◽  
Yeast Cells ◽  
Recessive Mutation ◽  
Yeast Saccharomyces Cerevisiae ◽  
Upstream Activating Sequence ◽  
A Site

ABSTRACT The alcohol dehydrogenase II (ADH2) gene of the yeast, Saccharomyces cerevisiae, is not transcribed during growth on fermentable carbon sources such as glucose. Growth of yeast cells in a medium containing only nonfermentable carbon sources leads to a marked increase or derepression of ADH2 expression. The recessive mutation, adr6-1, leads to an inability to fully derepress ADH2 expression and to an inability to sporulate. The ADR6 gene product appears to act directly or indirectly on ADH2 sequences 3' to or including the presumptive TATAA box. The upstream activating sequence (UAS) located 5' to the TATAA box is not required for the Adr6- phenotype. Here, we describe the isolation of a recombinant plasmid containing the wild-type ADR6 gene. ADR6 codes for a 4.4-kb RNA which is present during growth both on glucose and on nonfermentable carbon sources. Disruption of the ADR6 transcription unit led to viable cells with decreased ADHII activity and an inability to sporulate. This indicates that both phenotypes result from mutations within a single gene and that the adr6-1 allele was representative of mutations at this locus. The ADR6 gene mapped to the left arm of chromosome XVI at a site 18 centimorgans from the centromere.

scholarly journals The Identification and Characterization of ADR6, a Gene Required for Sporulation and for Expression of the Alcohol Dehydrogenase II Isozyme From Saccharomyces cerevisiae

Genetics ◽  
1987 ◽  
Vol 116 (4) ◽  
pp. 523-530
Author(s):  
Aileen K W Taguchi ◽  
Elton T Young
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Alcohol Dehydrogenase ◽  
Isocitrate Lyase ◽  
Carbon Sources ◽  
Recessive Mutation ◽  
Yeast Saccharomyces Cerevisiae ◽  
Upstream Activating Sequence ◽  
Adh Activity ◽  
Identification And Characterization

ABSTRACT The alcohol dehydrogenase II isozyme (enzyme, ADHII; structural gene, ADH2) of the yeast, Saccharomyces cerevisiae, is under stringent carbon catabolite control. This cytoplasmic isozyme exhibits negligible activity during growth in media containing fermentable carbon sources such as glucose and is maximal during growth on nonfermentable carbon sources. A recessive mutation, adr6-1, and possibly two other alleles at this locus, were selected for their ability to decrease Ty-activated ADH2-6 c expression. The adr6-1 mutation led to decreased ADHII activity in both ADH2-6c and ADH2+ strains, and to decreased levels of ADH2 mRNA. Ty transcription and the expression of two other carbon catabolite regulated enzymes, isocitrate lyase and malate dehydrogenase, were unaffected by the adr6-1 mutation. adr6-1/adr6-1strains were defective for sporulation, indicating that adr6 mutations may have pleiotropic effects. The sporulation defect was not a consequence of decreased ADH activity. Since the ADH2-6c mutation is due to insertion of a 5.6-kb Ty element at the TATAA box, it appears that the ADR6+-dependent ADHII activity required ADH2 sequences 3′ to or including the TATAA box. The ADH2 upstream activating sequence (UAS) was probably not required. The ADR6 locus was unlinked to the ADR1 gene which encodes another trans-acting element required for ADH2 expression.

scholarly journals Screening and directed evolution of transporters to improve xylodextrin utilization in the yeast Saccharomyces cerevisiae

2017 ◽  
Author(s):  
Chenlu Zhang ◽  
Ligia Acosta-Sampson ◽  
Vivian Yaci Yu ◽  
Jamie H. D. Cate
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Directed Evolution ◽  
Plant Biomass ◽  
Carbon Sources ◽  
Industrial Applications ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cellulosic Biofuel ◽  
Economic Production ◽  
Report Analysis ◽  
Selection Medium

AbstractThe economic production of cellulosic biofuel requires efficient and full utilization of all abundant carbohydrates naturally released from plant biomass by enzyme cocktails. Recently, we reconstituted the Neurospora crassa xylodextrin transport and consumption system in Saccharomyces cerevisiae, enabling growth of yeast on xylodextrins aerobically. However, the consumption rate of xylodextrin requires improvement for industrial applications, including consumption in anaerobic conditions. As a first step in this improvement, we report analysis of orthologues of the N. crassa transporters CDT-1 and CDT-2. Transporter ST16 from Trichoderma virens enables faster aerobic growth of S. cerevisiae on xylodextrins compared to CDT-2. ST16 is a xylodextrin-specific transporter, and the xylobiose transport activity of ST16 is not inhibited by cellobiose. Other transporters identified in the screen also enable growth on xylodextrins including xylotriose. Taken together, these results indicate that multiple transporters might prove useful to improve xylodextrin utilization in S. cerevisiae. Efforts to use directed evolution to improve ST16 from a chromosomally-integrated copy were not successful, due to background growth of yeast on other carbon sources present in the selection medium. Future experiments will require increasing the baseline growth rate of the yeast population on xylodextrins, to ensure that the selective pressure exerted on xylodextrin transport can lead to isolation of improved xylodextrin transporters.

scholarly journals CAT8, a new zinc cluster-encoding gene necessary for derepression of gluconeogenic enzymes in the yeast Saccharomyces cerevisiae.

1995 ◽  
Vol 15 (4) ◽  
pp. 1915-1922 ◽  
Author(s):  
D Hedges ◽  
M Proft ◽  
K D Entian
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Carbon Source ◽  
Gene Activation ◽  
Carbon Sources ◽  
Source Analysis ◽  
Yeast Saccharomyces Cerevisiae ◽  
Gluconeogenic Enzymes ◽  
Zinc Cluster ◽  
Promoter Fusion

The expression of gluconeogenic fructose-1,6-bisphosphatase (encoded by the FBP1 gene) depends on the carbon source. Analysis of the FBP1 promoter revealed two upstream activating elements, UAS1FBP1 and UAS2FBP1, which confer carbon source-dependent regulation on a heterologous reporter gene. On glucose media neither element was activated, whereas after transfer to ethanol a 100-fold derepression was observed. This gene activation depended on the previously identified derepression genes CAT1 (SNF1) (encoding a protein kinase) and CAT3 (SNF4) (probably encoding a subunit of Cat1p [Snf1p]). Screening for mutations specifically involved in UAS1FBP1 derepression revealed the new recessive derepression mutation cat8. The cat8 mutants also failed to derepress UAS2FBP1, and these mutants were unable to grow on nonfermentable carbon sources. The CAT8 gene encodes a zinc cluster protein related to Saccharomyces cerevisiae Gal4p. Deletion of CAT8 caused a defect in glucose derepression which affected all key gluconeogenic enzymes. Derepression of glucose-repressible invertase and maltase was still normally regulated. A CAT8-lacZ promoter fusion revealed that the CAT8 gene itself is repressed by Cat4p (Mig1p). These results suggest that gluconeogenic genes are derepressed upon binding of Cat8p, whose synthesis depends on the release of Cat4p (Mig1p) from the CAT8 promoter. However, gluconeogenic promoters are still glucose repressed in cat4 mutants, which indicates that in addition to its transcription, the Cat8p protein needs further activation. The observation that multicopy expression of CAT8 reverses the inability of cat1 and cat3 mutants to grow on ethanol indicates that Cat8p might be the substrate of the Cat1p/Cat3p protein kinase.

scholarly journals Cloning and characterization of BCY1, a locus encoding a regulatory subunit of the cyclic AMP-dependent protein kinase in Saccharomyces cerevisiae.

1987 ◽  
Vol 7 (4) ◽  
pp. 1371-1377 ◽  
Author(s):  
T Toda ◽  
S Cameron ◽  
P Sass ◽  
M Zoller ◽  
J D Scott ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Cyclic Amp ◽  
Carbon Sources ◽  
Regulatory Subunit ◽  
Dependent Protein Kinase ◽  
Yeast Saccharomyces Cerevisiae ◽  
Regulatory Subunits ◽  
Dependent Protein

We have cloned a gene (BCY1) from the yeast Saccharomyces cerevisiae that encodes a regulatory subunit of the cyclic AMP-dependent protein kinase. The encoded protein has a structural organization similar to that of the RI and RII regulatory subunits of the mammalian cyclic AMP-dependent protein kinase. Strains of S. cerevisiae with disrupted BCY1 genes do not display a cyclic AMP-dependent protein kinase in vitro, fail to grow on many carbon sources, and are exquisitely sensitive to heat shock and starvation.

Fatty acylation is important but not essential for Saccharomyces cerevisiae RAS function

1987 ◽  
Vol 7 (7) ◽  
pp. 2344-2351
Author(s):  
R J Deschenes ◽  
J R Broach
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Function ◽  
Membrane Fraction ◽  
Carbon Sources ◽  
Fatty Acyl ◽  
Yeast Saccharomyces Cerevisiae ◽  
Fatty Acyl Moiety ◽  
Fatty Acylation ◽  
Absolute Requirement

Two proteins in the yeast Saccharomyces cerevisiae that are encoded by the genes RAS1 and RAS2 are structurally and functionally homologous to proteins of the mammalian ras oncogene family. We examined the role of fatty acylation in the maturation of yeast RAS2 protein by creating mutants in the putative palmitate addition site located at the carboxyl terminus of the protein. Two mutations, Cys-318 to an opal termination codon and Cys-319 to Ser-319, were created in vitro and substituted in the chromosome in place of the normal RAS2 allele. These changes resulted in a failure of RAS2 protein to be acylated with palmitate and a failure of RAS2 protein to be localized to a membrane fraction. The mutations yielded a Ras2- phenotype with respect to the ability of the resultant mutants to grow on nonfermentable carbon sources and to complement ras1- mutants. However, overexpression of the ras2Ser-319 product yielded a Ras+ phenotype without a corresponding association of the mutant protein with the membrane fraction. We conclude that the presence of a fatty acyl moiety is important for localizing RAS2 protein to the membrane where it is active but that the fatty acyl group is not an absolute requirement of RAS2 protein function.

scholarly journals Linkage between Carbon Metabolism, Redox Status and Cellular Physiology in the Yeast Saccharomyces cerevisiae Devoid of SOD1 or SOD2 Gene

Genes ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 780 ◽  
Author(s):  
Roman Maslanka ◽  
Renata Zadrag-Tecza ◽  
Magdalena Kwolek-Mirek
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Metabolism ◽  
Redox Homeostasis ◽  
Carbon Sources ◽  
Pyridine Nucleotide ◽  
Redox Status ◽  
Yeast Cells ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cellular Physiology ◽  
Respiratory Conditions

Saccharomyces cerevisiae yeast cells may generate energy both by fermentation and aerobic respiration, which are dependent on the type and availability of carbon sources. Cells adapt to changes in nutrient availability, which entails the specific costs and benefits of different types of metabolism but also may cause alteration in redox homeostasis, both by changes in reactive oxygen species (ROS) and in cellular reductant molecules contents. In this study, yeast cells devoid of the SOD1 or SOD2 gene and fermentative or respiratory conditions were used to unravel the connection between the type of metabolism and redox status of cells and also how this affects selected parameters of cellular physiology. The performed analysis provides an argument that the source of ROS depends on the type of metabolism and non-mitochondrial sources are an important pool of ROS in yeast cells, especially under fermentative metabolism. There is a strict interconnection between carbon metabolism and redox status, which in turn has an influence on the physiological efficiency of the cells. Furthermore, pyridine nucleotide cofactors play an important role in these relationships.

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