Rapid ethanol production at elevated temperatures by engineered thermotolerant Kluyveromyces marxianus via the NADP(H)-preferring xylose reductase-xylitol dehydrogenase pathway.
Rapid ethanol production at elevated temperatures by engineered thermotolerant Kluyveromyces marxianus via the NADP(H)-preferring xylose reductase-xylitol dehydrogenase pathway.
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DOI：
10.1016/j.ymben.2015.07.008
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发表时间：
2015-09
影响因子：
8.4
通讯作者：
Jia Zhang;Biao Zhang;Dongmei Wang;Xiaolian Gao;Lianhong Sun;Jiong Hong
中科院分区：
文献类型：
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作者：
Jia Zhang;Biao Zhang;Dongmei Wang;Xiaolian Gao;Lianhong Sun;Jiong Hong
通过酵母将木糖转化为乙醇是一个挑战，因为在氧限制条件下氧化还原不平衡。耐热酵母马克斯克鲁维酵母（Kluyveromycesmarxianus）以木糖为碳源生长良好，但其木糖发酵能力较弱。在这项研究中，从粗糙脉孢菌的NADPH-偏好木糖还原酶（XR）和NADP+-偏好木糖醇脱氢酶（XDH）的突变体从树干毕赤酵母（树干毕赤酵母）的组合构建。通过过量表达多个下游基因，重组菌株的木糖发酵能力和氧化还原平衡得到显著改善。在这些代谢菌株中，辅酶的细胞内浓度和还原型辅酶/氧化型辅酶的比例显着增加。甘油-3-磷酸脱氢酶（GPD 1）的破坏，副产物，如甘油和乙酸，显着减少。生成的engineeredK。marxianusYZJ 088菌株在42 °C下从118.39g/L木糖产生44.95g/L乙醇，生产率为2.49g/L/h。YZJ 088实现了葡萄糖和木糖的共发酵，在42 °C下，木糖浓度为103.97 g/L，葡萄糖浓度为40.96 g/L，乙醇产量为51.43 g/L，产率为2.14 g/L/h。这些有希望的结果验证了YZJ 088菌株作为通过合成木糖同化途径从木糖生产乙醇的优异生产者。
Conversion of xylose to ethanol by yeasts is a challenge because of the redox imbalances under oxygen-limited conditions. The thermotolerant yeast Kluyveromyces marxianus grows well with xylose as a carbon source at elevated temperatures, but its xylose fermentation ability is weak. In this study, a combination of the NADPH-preferring xylose reductase (XR) from Neurospora crassa and the NADP+-preferring xylitol dehydrogenase (XDH) mutant from Scheffersomyces stipitis (Pichia stipitis) was constructed. The xylose fermentation ability and redox balance of the recombinant strains were improved significantly by over-expression of several downstream genes. The intracellular concentrations of coenzymes and the reduced coenzyme/oxidized coenzyme ratio increased significantly in these metabolic strains. The byproducts, such as glycerol and acetic acid, were significantly reduced by the disruption of glycerol-3-phosphate dehydrogenase (GPD1). The resulting engineeredK. marxianusYZJ088 strain produced 44.95 g/L ethanol from 118.39 g/L xylose with a productivity of 2.49 g/L/h at 42 °C. Additionally, YZJ088 realized glucose and xylose co-fermentation and produced 51.43 g/L ethanol from a mixture of 103.97 g/L xylose and 40.96 g/L glucose with a productivity of 2.14 g/L/h at 42 °C. These promising results validate the YZJ088 strain as an excellent producer of ethanol from xylose through the synthetic xylose assimilation pathway.