提高产乙醇大肠杆菌 LY180 对 5-羟甲基糠醛抗性的遗传变化。
Genetic changes that increase 5-hydroxymethyl furfural resistance in ethanol-producing Escherichia coli LY180.
机构信息
Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA.
出版信息
Biotechnol Lett. 2010 May;32(5):661-7. doi: 10.1007/s10529-010-0209-9. Epub 2010 Feb 4.
The ability of a biocatalyst to tolerate furan inhibitors present in hemicellulose hydrolysates is important for the production of renewable chemicals. This study shows EMFR9, a furfural-tolerant mutant of ethanologenic E. coli LY180, has also acquired tolerance to 5-hydroxymethyl furfural (5-HMF). The mechanism of action of 5-HMF and furfural appear similar. Furan tolerance results primarily from lower expression of yqhD and dkgA, two furan reductases with a low K(m) for NADPH. Furan tolerance was also increased by adding plasmids encoding a NADPH/NADH transhydrogenase (pntAB). Together, these results support the hypothesis that the NADPH-dependent reduction of furans by YqhD and DkgA inhibits growth by competing with biosynthesis for this limiting cofactor.
生物催化剂对木质纤维素水解物中存在的呋喃抑制剂的耐受性对于可再生化学品的生产非常重要。本研究表明，耐糠醛突变体乙醇梭菌 LY180 菌株 EMFR9 也获得了对 5-羟甲基糠醛（5-HMF）的耐受性。5-HMF 和糠醛的作用机制似乎相似。呋喃耐受性主要源于呋喃还原酶 yqhD 和 dkgA 的表达水平降低，这两种酶对 NADPH 的 K(m)值较低。添加编码 NADPH/NADH 转氢酶（pntAB）的质粒也可以增加呋喃耐受性。这些结果共同支持了这样一种假设，即 YqhD 和 DkgA 依赖 NADPH 的呋喃还原会与生物合成竞争这种有限的辅因子，从而抑制生长。
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