The expression of a Pichia stipitis xylose reductase mutant with higher KM for NADPH increases ethanol production from xylose in recombinant Saccharomyces cerevisiae
The expression of a Pichia stipitis xylose reductase mutant with higher KM for NADPH increases ethanol production from xylose in recombinant Saccharomyces cerevisiae
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DOI：
10.1002/bit.20737
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发表时间：
2006-03-05
影响因子：
3.8
通讯作者：
Gorwa-Grauslund, MF
中科院分区：
文献类型：
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作者：
Jeppsson, M;Bengtsson, O;Gorwa-Grauslund, MF
由酿酒酵母进行的木糖发酵需要引入木糖途径，其类似于在天然木糖利用酵母树干毕赤酵母和休哈塔假丝酵母中发现的木糖途径或类似于细菌途径。来自树干毕赤酵母的NAD（P）H依赖性XR和NAD（+）依赖性XDH的使用产生辅因子不平衡，导致木糖醇形成。用具有增加的NADPH K-M的突变XR替换天然树干毕赤酵母XR的效果（Kostrzynska等人，1998：FEMS Microbiol Lett 159：107-112）研究了重组S.酿酒酵母菌株。在携带突变XR的菌株中获得了伴随着木糖醇产量降低的乙醇产量增加。通量分析表明，携带突变XR的菌株利用更大比例的NADH进行木糖还原。突变XR的过量生产导致在恒化器培养（0.06/h）中以10 g/L葡萄糖和10 g/L木糖作为碳源的乙醇产率为0.40 g/g糖，木糖消耗速率为0.16 g/g生物质/h。(c)2005 Wiley Periodicals，Inc.
Xylose fermentation by Saccharomyces cerevisiae requires the introduction of a xylose pathway, either similar to that found in the natural xylose-utilizing yeasts Pichia stipitis and Candida shehatae or similar to the bacterial pathway. The use of NAD(P)H-dependent XR and NAD(+)-dependent XDH from P. stipitis creates a cofactor imbalance resulting in xylitol formation. The effect of replacing the native P. stipitis XR with a mutated XR with increased K-M for NADPH (Kostrzynska et al., 1998: FEMS Microbiol Lett 159:107-112) was investigated for xylose fermentation to ethanol by recombinant S. cerevisiae strains. Enhanced ethanol yields accompanied by decreased xylitol yields were obtained in strains carrying the mutated XR. Flux analysis showed that strains harboring the mutated XR utilized a larger fraction of NADH for xylose reduction. The overproduction of the mutated XR resulted in an ethanol yield of 0.40 g per gram of sugar and a xylose consumption rate of 0.16 g per gram of biomass per hour in chemostat culture (0.06/h) with 10 g/L glucose and 10 g/L xylose as carbon source. (c) 2005 Wiley Periodicals, Inc.