Multiple gene-mediated NAD(P)H-dependent aldehyde reduction is a mechanism of in situ detoxification of furfural and 5-hydroxymethylfurfural by Saccharomyces cerevisiae.
Furfural and 5-hydroxymethylfurfural (HMF) are representative inhibitors generated from biomass pretreatment using dilute acid hydrolysis that interfere with yeast growth and subsequent fermentation. Few yeast strains tolerant to inhibitors are available. In this study, we report a tolerant strain, Saccharomyces cerevisiae NRRL Y-50049, which has enhanced biotransformation ability to convert furfural to furan methanol (FM), HMF to furan di-methanol (FDM), and produce a normal yield of ethanol. Our recent identification of HMF and development of protocol to synthesize the HMF metabolic conversion product FDM allowed studies on fermentation metabolic kinetics in the presence of HMF and furfural. Individual gene-encoding enzymes possessing aldehyde reduction activities demonstrated cofactor preference for NADH or NADPH. However, protein extract from whole yeast cells showed equally strong aldehyde reduction activities coupled with either cofactor. Deletion of a single candidate gene did not affect yeast growth in the presence of the inhibitors. Our results suggest that detoxification of furfural and HMF by the ethanologenic yeast S. cerevisiae strain Y-50049 likely involves multiple gene mediated NAD(P)H-dependent aldehyde reduction. Conversion pathways of furfural and HMF relevant to glycolysis and ethanol production were refined based on our findings in this study.
Liu
Z Lewis
ZL
US Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, 1815 North University Street, Peoria, IL 61604, USA. zlewis.liu@ars.usda.gov
Moon
Jaewoong
J
Andersh
Brad J
BJ
Slininger
Patricia J
PJ
Weber
Scott
S
D000447:Aldehydes / Q000378:metabolism*; D001711:Biotransformation; D000431:Ethanol / Q000378:metabolism; D005662:Furaldehyde / Q000031:analogs & derivatives* / Q000378:metabolism*; D009243:NAD / Q000378:metabolism*; D009249:NADP / Q000378:metabolism*; D010084:Oxidation-Reduction; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion
D000447:Aldehydes; D029701:Saccharomyces cerevisiae Proteins; D009243:NAD; D000431:Ethanol; D009249:NADP; C008046:5-hydroxymethylfurfural; D005662:Furaldehyde