Use of snail enzyme for the selection of glucose- and mannose-negative mutants in Saccharomyces cerevisiae

1976 ◽  
Vol 34 (1) ◽  
pp. 123-130 ◽  
Author(s):  
Luis S. Herrera
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Snail Enzyme ◽  
Selection Of

Constitutive and inducible Saccharomyces cerevisiae promoters: evidence for two distinct molecular mechanisms

1986 ◽  
Vol 6 (11) ◽  
pp. 3847-3853
Author(s):  
K Struhl
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Molecular Mechanisms ◽  
Normal Growth ◽  
Regulatory Elements ◽  
Growth Conditions ◽  
Physical Structure ◽  
Base Pairs ◽  
Inducible Promoters ◽  
Upstream Promoter ◽  
Selection Of

his3 and pet56 are adjacent Saccharomyces cerevisiae genes that are transcribed in opposite directions from initiation sites that are separated by 200 base pairs. Under normal growth conditions, in which his3 and pet56 are transcribed at similar basal levels, a poly(dA-dT) sequence located between the genes serves as the upstream promoter element for both. In contrast, his3 but not pet56 transcription is induced during conditions of amino acid starvation, even though the critical regulatory site is located upstream of both respective TATA regions. Moreover, only one of the two normal his3 initiation sites is subject to induction. From genetic and biochemical evidence, I suggest that the his3-pet56 intergenic region contains constitutive and inducible promoters with different properties. In particular, two classes of TATA elements, constitutive (Tc) and regulatory (Tr), can be distinguished by their ability to respond to upstream regulatory elements, by their effects on the selection of initiation sites, and by their physical structure in nuclear chromatin. Constitutive and inducible his3 transcription is mediated by distinct promoters representing each class, whereas pet56 transcription is mediated by a constitutive promoter. Molecular mechanisms for these different kinds of S. cerevisiae promoters are proposed.

scholarly journals The Lipomyces starkeyi gene Ls120451 encodes a cellobiose transporter that enables cellobiose fermentation in Saccharomyces cerevisiae

2020 ◽  
Vol 20 (3) ◽  
Author(s):  
Jorg C de Ruijter ◽  
Kiyohiko Igarashi ◽  
Merja Penttilä
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Aspergillus Niger ◽  
Heterologous Expression ◽  
In Silico ◽  
Penicillium Oxalicum ◽  
Microbial Fermentation ◽  
Lipomyces Starkeyi ◽  
Yeast Saccharomyces Cerevisiae ◽  
Sugar Transporters ◽  
Selection Of

ABSTRACT Processed lignocellulosic biomass is a source of mixed sugars that can be used for microbial fermentation into fuels or higher value products, like chemicals. Previously, the yeast Saccharomyces cerevisiae was engineered to utilize its cellodextrins through the heterologous expression of sugar transporters together with an intracellular expressed β-glucosidase. In this study, we screened a selection of eight (putative) cellodextrin transporters from different yeast and fungal hosts in order to extend the catalogue of available cellobiose transporters for cellobiose fermentation in S. cerevisiae. We confirmed that several in silico predicted cellodextrin transporters from Aspergillus niger were capable of transporting cellobiose with low affinity. In addition, we found a novel cellobiose transporter from the yeast Lipomyces starkeyi, encoded by the gene Ls120451. This transporter allowed efficient growth on cellobiose, while it also grew on glucose and lactose, but not cellotriose nor cellotetraose. We characterized the transporter more in-depth together with the transporter CdtG from Penicillium oxalicum. CdtG showed to be slightly more efficient in cellobiose consumption than Ls120451 at concentrations below 1.0 g/L. Ls120451 was more efficient in cellobiose consumption at higher concentrations and strains expressing this transporter grew slightly slower, but produced up to 30% more ethanol than CdtG.

scholarly journals Selection of Saccharomyces cerevisiae Starter Strain for Merwah Wine

Fermentation ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 43
Author(s):  
Nadine Feghali ◽  
Angela Bianco ◽  
Giacomo Zara ◽  
Edouard Tabet ◽  
Chantal Ghanem ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acetic Acid ◽  
Pilot Scale ◽  
Molecular Monitoring ◽  
Technological Parameters ◽  
Sensorial Analysis ◽  
Spontaneous Fermentation ◽  
Wine Production ◽  
Wild Yeasts ◽  
Selection Of

In order to select Saccharomyces cerevisiae starter strains for ‘‘Merwah’’ wine production, three strains (M.6.16, M.10.16, and M.4.17) previously isolated from ‘‘Merwah’’ must and characterized at the lab scale were tested in pilot-scale fermentation in a Lebanese winery during the 2019 vintage. The three inoculated musts were compared to that obtained with a spontaneous fermentation. During the fermentations, must samples were taken to evaluate the dominance of the inoculated strains, and at the end of fermentation, the obtained wines were subjected to chemical and sensorial characterization. Molecular monitoring by interdelta analysis revealed that only M.4.17 was able to complete the fermentation and dominate over the wild yeasts. Based on the analysis of principal technological parameters (i.e., residual sugar, fermentative vigor, sulfur production, and acetic acid) and sensorial analysis of the wines obtained, M.4.17 was selected as an adequate starter for the production of typical ‘‘Merwah’’ wine.

scholarly journals Novel Approach in the Construction of Bioethanol-Producing Saccharomyces cerevisiae Hybrids

2019 ◽  
Vol 57 (1) ◽  
pp. 5-16 ◽  
Author(s):  
Anamarija Štafa ◽  
Andrea Pranklin ◽  
Ivan Krešimir Svetec ◽  
Božidar Šantek ◽  
Marina Svetec Miklenić ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Targeting ◽  
Co2 Production ◽  
Production Test ◽  
Fermentation Inhibitors ◽  
Lignocellulosic Hydrolysates ◽  
Novel Approach ◽  
Ethanol Producer ◽  
High Ethanol ◽  
Selection Of

Bioethanol production from lignocellulosic hydrolysates requires a producer strain that tolerates both the presence of growth and fermentation inhibitors and high ethanol concentrations. Therefore, we constructed heterozygous intraspecies hybrid diploids of Saccharomyces cerevisiae by crossing two natural S. cerevisiae isolates, YIIc17_E5 and UWOPS87-2421, a good ethanol producer found in wine and a strain from the flower of the cactus Opuntia megacantha resistant to inhibitors found in lignocellulosic hydrolysates, respectively. Hybrids grew faster than parental strains in the absence and in the presence of acetic and levulinic acids and 2-furaldehyde, inhibitors frequently found in lignocellulosic hydrolysates, and the overexpression of YAP1 gene increased their survival. Furthermore, although originating from the same parental strains, hybrids displayed different fermentative potential in a CO2 production test, suggesting genetic variability that could be used for further selection of desirable traits. Therefore, our results suggest that the construction of intraspecies hybrids coupled with the use of genetic engineering techniques is a promising approach for improvement or development of new biotechnologically relevant strains of S. cerevisiae. Moreover, it was found that the success of gene targeting (gene targeting fidelity) in natural S. cerevisiae isolates (YIIc17_E5α and UWOPS87-2421α) was strikingly lower than in laboratory strains and the most frequent off-targeting event was targeted chromosome duplication.

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