Abstract: Xylose fermentation is one of the bottleneck of cellulosic ethanol industry. The transformation of Saccharomyces cerevisiae for xylose metabolism has become one of the research hotspot at present. In order to study the influence of CIT2 gene on xylose utilization of Saccharomyces cerevisiae strain C5D-P-M for glucose and xylose co-fermentation, the CIT2 gene disruption cassette produced by overlapping PCR technology, transformed into C5D-P-M for knockout of CIT2 by homologous recombination and mutant strain C5D-P-M-CIT2Δ was gained finally. In contrast with C5D-P-M, the growth rate, glucose utilization, xylose utilization, and ethanol production of C5D-P-M-CIT2Δ had improved to some extent. The result suggested CIT2 gene is one factor that can influence the xylose utilization and its knockout can improve xylose utilization of Saccharomyces cerevisiae.

Key words: Saccharomyces cerevisiae, CIT2 gene, gene knockout, xylose metabolism

摘要： 木糖利用困难是秸秆燃料乙醇产业化的制约因素，改造酿酒酵母使其能够代谢木糖生成乙醇是当前研究的热点之一。为了研究CIT2基因对遗传改良酿酒酵母C5D-P-M菌株中葡萄糖与木糖共发酵过程中木糖利用的影响，设计引物并应用重叠PCR技术获得敲除CIT2基因的敲除组件，通过同源重组的方法将C5D-P-M中的CIT2基因敲除得到突变菌株C5D-P-M-CIT2Δ。通过对出发菌株和突变菌株的生长速率、葡萄糖利用率、木糖利用率及乙醇产量进行研究，结果表明突变菌株C5D-P-M-CIT2Δ的上述指标比出发菌株C5D-P-M均有一定程度的提高。因此推测，酿酒酵母中CIT2基因是影响木糖利用的因素之一，CIT2基因的敲除可提高酿酒酵母的木糖利用率。

关键词: 酿酒酵母, CIT2基因, 基因敲除, 木糖代谢