Potent l-lactic acid assimilation of the fermentative and heterothallic haploid yeast Saccharomyces cerevisiae NAM34-4C

2014 ◽  
Vol 117 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Masataka Tomitaka ◽  
Hisataka Taguchi ◽  
Masayoshi Matsuoka ◽  
Shigeru Morimura ◽  
Kenji Kida ◽  
...  
eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
David M Garcia ◽  
David Dietrich ◽  
Jon Clardy ◽  
Daniel F Jarosz

Robust preference for fermentative glucose metabolism has motivated domestication of the budding yeast Saccharomyces cerevisiae. This program can be circumvented by a protein-based genetic element, the [GAR+] prion, permitting simultaneous metabolism of glucose and other carbon sources. Diverse bacteria can elicit yeast cells to acquire [GAR+], although the molecular details of this interaction remain unknown. Here we identify the common bacterial metabolite lactic acid as a strong [GAR+] inducer. Transient exposure to lactic acid caused yeast cells to heritably circumvent glucose repression. This trait had the defining genetic properties of [GAR+], and did not require utilization of lactic acid as a carbon source. Lactic acid also induced [GAR+]-like epigenetic states in fungi that diverged from S. cerevisiae ~200 million years ago, and in which glucose repression evolved independently. To our knowledge, this is the first study to uncover a bacterial metabolite with the capacity to potently induce a prion.


2014 ◽  
Vol 7 (3) ◽  
pp. 313-320 ◽  
Author(s):  
M. Piotrowska ◽  
J. Roszak ◽  
M. Stańczyk ◽  
J. Palus ◽  
E. Dziubałtowska ◽  
...  

The aim of this study was to examine three strains of the yeast Saccharomyces cerevisiae and three strains of lactic acid bacteria belonging to the genus Lactobacillus for their antifungal activity against the ochratoxin A producer Aspergillus westerdijkiae, as well as for their effect on OTA genotoxicity and cytotoxicity. When inoculated simultaneously, fungal growth was completely inhibited by S. cerevisiae. In the case of lactic acid bacteria, growth inhibition also occurred but to a less extent. A significant decrease in toxin production in co-culture with the yeast strains and LAB was observed. The supernatant of 24-h-old cultures of yeast strains in medium with OTA did not influence significantly the viability of porcine kidney epithelial LLC-PK1 cell line, whereas the supernatant from the LAB increased the viability compared to the control. Regarding genotoxicity, a decreased fragmentation of DNA was observed in the presence of the supernatant from wine and brewing yeasts, and Lactobacillus brevis strains. Based on the results obtained, it might be concluded that S. cerevisiae yeasts and lactic acid bacteria could be used to minimise the negative effect of OTA on humans and animals.


2019 ◽  
Vol 19 (6) ◽  
Author(s):  
Timothy L Turner ◽  
Stephan Lane ◽  
Lahiru N Jayakody ◽  
Guo-Chang Zhang ◽  
Heejin Kim ◽  
...  

ABSTRACT Microorganisms have evolved to produce specific end products for many reasons, including maintaining redox balance between NAD+ and NADH. The yeast Saccharomyces cerevisiae, for example, produces ethanol as a primary end product from glucose for the regeneration of NAD+. Engineered S. cerevisiae strains have been developed to ferment lignocellulosic sugars, such as xylose, to produce lactic acid by expression of a heterologous lactate dehydrogenase (ldhA from Rhizopus oryzae) without genetic perturbation to the native ethanol pathway. Surprisingly, the engineered yeast strains predominantly produce ethanol from glucose, but produce lactic acid as the major product from xylose. Here, we provide initial evidence that the shift in product formation from ethanol to lactic acid during xylose fermentation is at least partially dependent on the presence of functioning monocarboxylate transporter genes/proteins, including JEN1 and ADY2, which are downregulated and unstable in the presence of glucose, but upregulated/stable on xylose. Future yeast metabolic engineering studies may find the feedstock/carbon selection, such as xylose, an important step toward improving the yield of target end products.


Author(s):  
Anna Ylinen ◽  
Hannu Maaheimo ◽  
Adina Anghelescu-Hakala ◽  
Merja Penttilä ◽  
Laura Salusjärvi ◽  
...  

Abstract Polyhydroxyalkanoates (PHA) provide biodegradable and bio-based alternatives to conventional plastics. Incorporation of 2-hydroxy acid monomers into polymer, in addition to 3-hydroxy acids, offers possibility to tailor the polymer properties. In this study, poly(D-lactic acid) (PDLA) and copolymer P(LA-3HB) were produced and characterized for the first time in the yeast Saccharomyces cerevisiae. Expression of engineered PHA synthase PhaC1437Ps6–19, propionyl-CoA transferase Pct540Cp, acetyl-CoA acetyltransferase PhaA, and acetoacetyl-CoA reductase PhaB1 resulted in accumulation of 3.6% P(LA-3HB) and expression of engineered enzymes PhaC1Pre and PctMe resulted in accumulation of 0.73% PDLA of the cell dry weight. According to NMR, P(LA-3HB) contained D-Lactic acid repeating sequences. For reference, expression of PhaA, PhaB1, and PHA synthase PhaC1 resulted in accumulation 11% poly(hydroxybutyrate) (PHB) of the cell dry weight. Weight average molecular weights of these polymers were comparable to similar polymers produced by bacterial strains, 24.6 kDa, 6.3 kDa, and 1 130 kDa, for P(LA-3HB), PDLA, and PHB, respectively. The results suggest that yeast, as a robust and acid tolerant industrial production organism, could be suitable for production of 2-hydroxy acid containing PHAs from sugars or from 2-hydroxy acid containing raw materials. Moreover, the wide substrate specificity of PHA synthase enzymes employed increases the possibilities for modifying copolymer properties in yeast in the future.


2017 ◽  
Vol 41 (1) ◽  
pp. 61 ◽  
Author(s):  
Ahmad Sofyan ◽  
Yantyati Widyastuti ◽  
Ristianto Utomo ◽  
Lies Mira Yusiati

This study was conducted to determine effectiveness of inoculants consisted of lactic acid bacteria Lactobacillus plantarum (Lp) and yeast Saccharomyces cerevisiae (Sc) combined with addition of rice bran on the physico-chemical characteristics and palatability of king grass (Pennisetum hybrid) silage. The experiment was arranged on the factorial randomized design (3x3) consisting of the inoculants treatments (control, Lp, Lp+Sc) and the addition level of rice bran (0, 5 and 10%). The measured variables were physico-chemical characteristics i.e. colour, odour, pH, lactic acid, Fleigh points, and palatability of silage. Inoculation of Lp and Lp+Sc improved silage odour and reduced fungal contamination. Silage was treated by Lp+Sc and rice bran (5-10%) showed reduction of pH and an increase of lactic acid and Fleigh points. However, interaction between inoculants and rice bran treatment was not significance. Either inoculation or addition of rice bran tended to enhance the palatability of silage in cattle. It concluded that the addition of inoculants L. plantarum and S. cerevisiae with/without addition of 5-10% rice bran could improve the physico-chemical characteristics of silage and its palatability to ruminant.


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