Challenges of non-flocculating Saccharomyces cerevisiae haploid strain against inhibitory chemical complex for ethanol production

• Published in: Bioresource technology 2017-12, Vol.245 (Pt B), p.1436-1446
• Main Authors: Kahar, Prihardi, Riyanti, Eny Ida, Otsuka, Hiromi, Matsumoto, Hana, Kihira, Chie, Ogino, Chiaki, Kondo, Akihiko
• Format: Article
• Language: English
• Subjects: Ethanol; Fermentation; Haploidy; Inhibitor tolerance; Inhibitory chemical complex; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2017.06.009

•Non-flocculating Saccharomyces cerevisae NBRC849 was robust haploid yeast.•Upregulations of ZWF1 and ALD6 were required for yeast robustness against inhibitors.•NADPH and NADH were used for in situ detoxification process of inhibitors.•ABC and polyamine transporters play an important role in the inhibitor efflux.•The enhancement of metabolic flux to the shikimic pathway is important for cell survival. This study provides insight observation based on the gene expression and the metabolomic analysis of the natural robust yeast Saccharomyces cerevisiae NBRC849 during the fermentation in the medium containing inhibitory chemical complexes (ICC) at different concentrations. The tolerance mechanisms involved in the strain might have existed through the upregulation of genes involved in NAD(H)/NADP(H) cofactors generations (ALD6, ZWF1, GND1), membrane robustness for efflux pump (YOR1, PDR5, TPO3) and cation/polyamine transport (TPO3). The alteration of metabolic flux to the shikimic pathway was also found in this strain, resulted in the enhanced formation of aromatic amino acid required for cell survival. Enhanced expression of these genes as well as the increase of metabolic flux to shikimic pathway were suggested to result in the robustness of non-flocculating S. cerevisiae haploid strain.