Genomic mechanisms of stress tolerance for the industrial yeast Saccharomyces cerevisiae against major chemical classes of inhibitors

Authors: LIU, ZONGLIN

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/24/2015
Publication Date: 7/24/2015
Citation: Liu, Z. 2015. Genomic mechanisms of stress tolerance for the industrial yeast Saccharomyces cerevisiae against major chemical classes of inhibitors [abstract]. Meeting Abstract. p. 1.

Interpretive Summary: Numerous toxic chemical compounds liberated from lignocellulosic biomass pretreatment inhibit subsequent microbial fermentation that pose a significant challenge to a sustainable and renewable bio-based fermentation industry. Toxin removal procedures by physical or chemical means are essentially impractical economically. At ARS, we developed a tolerant industrial yeast strain that is able to reduce major chemical classes of inhibitors into less toxic or non-toxic compounds while producing ethanol. Using genomic studies, we defined mechanisms of in situ detoxification from novel gene functions to cofactor regeneration balance and reprogrammed pathways. We identified three key regulatory elements mediating the yeast tolerance; characterized signature gene expression involved in cell wall integrity; and revealed significant roles of MAPK signaling pathways for the tolerance of the industrial yeast. Our comparative genomic studies suggest that the mechanisms of the yeast tolerance are far beyond the above mentioned elements and the global mechanism is yet to be determined. The rewired networks from the evolved tolerance yeast demonstrated significant impact to at least 44 downstream pathways. This presentation will address the tolerance of the industrial yeast from novel gene functions to complex gene regulatory networks for better understanding of genomic mechanisms of the tolerance against major chemical classes of inhibitors. Such knowledge will aid the next generation biocatalyst development for production of chemicals and advanced biofuels from lignocellulosic biomass.

Technical Abstract: Numerous toxic chemical compounds liberated from lignocellulosic biomass pretreatment inhibit subsequent microbial fermentation that pose a significant challenge to a sustainable and renewable bio-based fermentation industry. Toxin removal procedures by physical or chemical means are essentially impractical economically. At ARS, we developed a tolerant industrial yeast strain that is able to reduce major chemical classes of inhibitors into less toxic or non-toxic compounds while producing ethanol. Using genomic studies, we defined mechanisms of in situ detoxification from novel gene functions to cofactor regeneration balance and reprogrammed pathways. We identified three key regulatory elements mediating the yeast tolerance; characterized signature gene expression involved in cell wall integrity; and revealed significant roles of MAPK signaling pathways for the tolerance of the industrial yeast. Our comparative genomic studies suggest that the mechanisms of the yeast tolerance are far beyond the above mentioned elements and the global mechanism is yet to be determined. The rewired networks from the evolved tolerance yeast demonstrated significant impact to at least 44 downstream pathways. This presentation will address the tolerance of the industrial yeast from novel gene functions to complex gene regulatory networks for better understanding of genomic mechanisms of the tolerance against major chemical classes of inhibitors. Such knowledge will aid the next generation biocatalyst development for production of chemicals and advanced biofuels from lignocellulosic biomass.