Construction of a xylose-metabolizing yeast by genome integration of xylose isomerase gene and investigation of the effect of xylitol on fermentation
Construction of a xylose-metabolizing yeast by genome integration of xylose isomerase gene and investigation of the effect of xylitol on fermentation
复制标题
DOI：
10.1007/s00253-010-2870-2
复制
发表时间：
2010-11-01
影响因子：
5
通讯作者：
Kondo, Akihiko
中科院分区：
文献类型：
--
作者：
Tanino, Takanori;Hotta, Atsushi;Kondo, Akihiko
通过将木糖异构酶（XI）过表达盒多拷贝整合到酿酒酵母MT 8 -1菌株的基因组中来构建具有XI途径的酵母。所得到的酵母菌株成功地从作为唯一碳源的木糖和由木糖和葡萄糖组成的混合糖生产乙醇，而没有任何适应程序。木糖和混合糖发酵的乙醇产率分别为理论碳回收率的61.9%和62.2%。敲除宿主酵母菌株的编码非特异性醛糖还原酶的基因GRE 3改善了发酵特性。使用GRE 3活性酵母作为宿主菌株，不仅比乙醇生产速率而且木糖消耗速率都比具有XI途径的木糖代谢酵母提高了两倍以上。此外，还证明了培养基中的木糖醇对具有基于XI的木糖代谢途径的酵母从木糖生产乙醇表现出浓度依赖性抑制作用。从我们的研究结果来看，XI途径整合和GRE 3敲除的组合可以导致巩固的木糖同化途径和增加的乙醇生产力。
A yeast with the xylose isomerase (XI) pathway was constructed by the multicopy integration of XI overexpression cassettes into the genome of the Saccharomyces cerevisiae MT8-1 strain. The resulting yeast strain successfully produced ethanol from both xylose as the sole carbon source and a mixed sugar, consisting of xylose and glucose, without any adaptation procedure. Ethanol yields in the fermentation from xylose and mixed sugar were 61.9% and 62.2% of the theoretical carbon recovery, respectively. Knockout of GRE3, a gene encoding nonspecific aldose reductase, of the host yeast strain improved the fermentation profile. Not only specific ethanol production rates but also xylose consumption rates was improved more than twice that of xylose-metabolizing yeast with the XI pathway using GRE3 active yeast as the host strain. In addition, it was demonstrated that xylitol in the medium exhibits a concentration-dependent inhibition effect on the ethanol production from xylose with the yeast harboring the XI-based xylose metabolic pathway. From our findings, the combination of XI-pathway integration and GRE3 knockout could be result in a consolidated xylose assimilation pathway and increased ethanol productivity.