辅酶工程在酿酒酵母木糖代谢工程中的研究进展

辅酶工程（cofactor engineering）是代谢工程的一个重要分支，它通过改变辅酶的再生途径，达到改变细胞内代谢产物构成的目的。介绍了酿酒酵母(Saccharomyces cerevisiae)木糖代谢工程中，利用辅酶工程解决氧化还原平衡问题的研究进展，包括引入转氢酶系统，增加代谢中可利用的NADPH，实现NADH的厌氧氧化等策略。同时介绍了改变XR、XDH辅酶偏好的研究进展。

Research Progress in Cofactor Engineering of Xylose Metabolism in Recombinant Saccharomyces cerevisiae

Cofactor engineering, a vital part of metabolism engineering, changes the redox cofactor regeneration approach. Its main goal is to rebuild the components of metabolic products. The bioconversion of xylose for the production of ethanol is being studied intensively because ethanol is an alternative energy source and a potential liquid fuel. Saccharomyces cerevisiae has been traditionally used in producing ethanol from fermentable sugars but it cannot utilize xylose, only its isomer xylulose. Introduction of the xylose fermentation pathway from Pichia stipitis into S. cerevisiae enables xylose utilization in recombinant S. cerevisiae, but the ethanol yields of xylose fermentation with recombinant S. cerevisiae has been low and large amounts of the byproduct xylitol are produced. The major reason is that the catabolism of xylose with the fungal pathway leads an imbalance of redox cofactor. The process of the catabolism of xylose requires NADPH and NAD~ , both of which have to be regenerated in separated processes. More and more attention has therefore focused on the redox cofactor balance in S. cerevisia. The research progress of cofactor engineering to solve the imbalance of redox cofactor in xylose metabolism recombinant S. cerevisiae was introduced. This included expression of transhydrogenase, increasing the utilization of NADPH, and achieving the anaerobic reoxidation of NADH. Reversing the cofactor specificity of enzymes is another effective way.