Multiple gene-mediated NAD(P)H-dependent aldehyde reduction is a mechanism of in situ detoxification of furfural and 5-hydroxymethylfurfural by Saccharomyces cerevisiae
Multiple gene-mediated NAD(P)H-dependent aldehyde reduction is a mechanism of in situ detoxification of furfural and 5-hydroxymethylfurfural by Saccharomyces cerevisiae
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DOI：
10.1007/s00253-008-1702-0
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发表时间：
2008-12-01
影响因子：
5
通讯作者：
Weber, Scott
中科院分区：
文献类型：
--
作者：
Liu, Z. Lewis;Moon, Jaewoong;Weber, Scott
糠醛和5-羟甲基糠醛（HMF）是由使用稀酸水解的生物质预处理产生的代表性抑制剂，其干扰酵母生长和随后的发酵。很少有对抑制剂耐受的酵母菌株可用。在这项研究中，我们报告了一个耐受菌株，酿酒酵母NRRL Y-50049，它具有增强的生物转化能力，将糠醛转化为呋喃甲醇（FM），将HMF转化为呋喃二甲醇（FDM），并产生正常产量的乙醇。我们最近鉴定了HMF并开发了合成HMF代谢转化产物FDM的方案，从而可以在HMF和糠醛存在下研究发酵代谢动力学。具有醛还原活性的单个基因编码酶表现出对NADH或NADPH的辅因子偏好。然而，从整个酵母细胞的蛋白质提取物显示出同样强的醛还原活性加上任一辅因子。在抑制剂存在下，单个候选基因的缺失不影响酵母的生长。结果表明，产乙醇酵母S.酿酒酵母菌株Y-50049可能涉及多个基因介导的NAD（P）H依赖性醛还原。基于我们在这项研究中的发现，改进了与糖酵解和乙醇生产相关的糠醛和HMF的转化途径。
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.