Matsushika Akinori, Hoshino Tamotsu
Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-0046, Japan.
J Ind Microbiol Biotechnol. 2015 Dec;42(12):1623-31. doi: 10.1007/s10295-015-1695-5. Epub 2015 Oct 5.
The Saccharomyces cerevisiae HAP4 gene encodes a transcription activator that plays a key role in controlling the expression of genes involved in mitochondrial respiration and reductive pathways. This work examines the effect of knockout of the HAP4 gene on aerobic ethanol production in a xylose-utilizing S. cerevisiae strain. A hap4-deleted recombinant yeast strain (B42-DHAP4) showed increased maximum concentration, production rate, and yield of ethanol compared with the reference strain MA-B42, irrespective of cultivation medium (glucose, xylose, or glucose/xylose mixtures). Notably, B42-DHAP4 was capable of producing ethanol from xylose as the sole carbon source under aerobic conditions, whereas no ethanol was produced by MA-B42. Moreover, the rate of ethanol production and ethanol yield (0.44 g/g) from the detoxified hydrolysate of wood chips was markedly improved in B42-DHAP4 compared to MA-B42. Thus, the results of this study support the view that deleting HAP4 in xylose-utilizing S. cerevisiae strains represents a useful strategy in ethanol production processes.
酿酒酵母HAP4基因编码一种转录激活因子，该因子在控制参与线粒体呼吸和还原途径的基因表达中起关键作用。这项工作研究了敲除HAP4基因对利用木糖的酿酒酵母菌株有氧乙醇生产的影响。与参考菌株MA - B42相比，缺失hap4的重组酵母菌株（B42 - DHAP4）的乙醇最大浓度、生产率和产量均有所提高，无论培养基是葡萄糖、木糖还是葡萄糖/木糖混合物。值得注意的是，B42 - DHAP4能够在有氧条件下以木糖作为唯一碳源生产乙醇，而MA - B42不产生乙醇。此外，与MA - B42相比，B42 - DHAP4从木屑解毒水解产物中产生乙醇的速率和乙醇产量（0.44 g/g）显著提高。因此，本研究结果支持以下观点：在利用木糖的酿酒酵母菌株中删除HAP4是乙醇生产过程中的一种有用策略。
