Adaptive response of yeasts to furfural and 5-hydroxymethylfurfural and new chemical evidence for HMF conversion to 2,5-bis-hydroxymethlfuran
Adaptive response of yeasts to furfural and 5-hydroxymethylfurfural and new chemical evidence for HMF conversion to 2,5-bis-hydroxymethlfuran
复制标题
DOI：
10.1007/s10295-004-0148-3
复制
发表时间：
2004-09-01
影响因子：
3.4
通讯作者：
Gorsich, SW
中科院分区：
文献类型：
--
作者：
Liu, ZL;Slininger, PJ;Gorsich, SW
可再生木质纤维素材料是用于生物乙醇生产的有吸引力的低成本原料。糠醛和5-羟甲基糠醛（HMF）是由木质纤维素酸水解为用于发酵的单糖产生的最有效的抑制性化合物之一。在酿酒酵母ATCC 211239和NRRL Y-12632以及树干毕赤酵母NRRL Y-7124中，确定糠醛和HMF抑制在10至120 mM的浓度下是剂量依赖性的。在相同浓度下，酵母菌株对糠醛的抑制比HMF更敏感，而糠醛和HMF的组合处理协同抑制细胞生长。从菌株NRRL Y-12632的培养上清液中分离出由HMF转化的代谢产物，并最终鉴定为2，5-双-羟甲基呋喃，其为先前假定的HMF醇，具有C6 H8 O3的组成和128的分子量。提出在HMF存在下，酵母以与糠醛类似的方式将HMF的呋喃环上的醛基还原成醇。与HMF转化相关的快速酵母发酵和生长速率证明，这种生物转化代谢物的蓄积对酵母培养物的毒性可能低于HMF。酵母菌适应和转化糠醛和HMF的能力为这些抑制剂的原位解毒提供了潜力，并为进一步开发用于生物燃料生产的高度耐受菌株提供了遗传基础。
Renewable lignocellulosic materials are attractive low-cost feedstocks for bioethanol production. Furfural and 5-hydroxymethylfurfural (HMF) are among the most potent inhibitory compounds generated from acid hydrolysis of lignocelluloses to simple sugars for fermentation. In Saccharomyces cerevisiae ATCC 211239 and NRRL Y-12632 and Pichia stipitis NRRL Y-7124, furfural and HMF inhibition were determined to be dose-dependent at concentrations from 10 to 120 mM. The yeast strains were more sensitive to inhibition by furfural than HMF at the same concentration, while combined treatment of furfural and HMF synergistically suppressed cell growth. A metabolite transformed from HMF by strain NRRL Y-12632 was isolated from the culture supernatant, and conclusively identified as 2,5-bis-hydroxymethylfuran, a previously postulated HMF alcohol, with a composition Of C6H8O3 and a molecular weight of 128. It is proposed that, in the presence of HMF, the yeast reduces the aldehyde group on the furan ring of HMF into an alcohol, in a similar manner as for furfural. The accumulation of this biotransformed metabolite may be less toxic to yeast cultures than HMF, as evidenced by the rapid yeast fermentation and growth rates associated with HMF conversion. The ability of yeasts to adapt to and transform furfural and HMF offers the potential for in situ detoxification of these inhibitors and suggests a genetic basis for further development of highly tolerant strains for biofuel production.