Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/8/2005
Publication Date: 10/9/2005
Citation: Gorsich, S.W. 2005. Novel genes that provide increased stress tolerance in Saccharomyces cerevisiae [abstract]. Southern Great Lakes Local Section of the Society for Industrial Microbiology. Paper No. 2.
Technical Abstract: The release of useable sugars from lignocellulose biomass for industrial fuel-ethanol fermentation is often facilitated by a weak acid hydrolysis step. As a consequence, inhibitors such as furfural and 5-hydroxymethylfurfural (HMF) are formed as degradation products of xylose and glucose, respectively. These and other inhibitors present an environment which elicits the expression of stress-related genes in Saccharomyces cerevisiae. Recently, pentose phosphate pathway (PPP) genes from S. cerevisiae, undetermined genes from Coniochaeta ligniaria, and one mycotoxin resistance gene, TRI101, from Fusarium graminearum were identified as important in furfural stress tolerance. The PPP genes include, GND1, ZWF1, TKL1, and RPE1; and when disrupted, grow poorly compared to wild-type yeast in the presence of 25 mM furfural. When overexpressed, there is a growth advantage in the presence of high concentrations of furfural (50 mM). Since the PPP is linked to oxidative damage, we measured and detected increased reactive oxygen species, membrane damage, and chromatin damage in cells stressed with furfural. Interestingly by overexpressing the one gene from F. graminearum, TRI101, in S. cerevisiae, we observe a growth advantage in the presence of HMF, which has a reactive hydroxyl group. Moreover, exposing S. cerevisiae to the mycotoxin DAS also increases membrane damage. Together, these genes are revealing interesting trends about the cells response to stress.