Tianjin University of Science and Technology, P.R. China.
Can J Microbiol. 2010 Jun;56(6):495-500. doi: 10.1139/w10-032.
Fermentation properties under the control of multiple genes are difficult to alter with traditional methods in Saccharomyces cerevisiae. Here, a novel genome engineering approach is developed to improve ethanol production in very high gravity fermentation with 300 g/L glucose as the carbon source. This strategy involved constructing aneuploid strains on the base of tetraploid cells. The tetraploid strain was constructed by using the plasmid YCplac33-GHK, which harbored the HO gene encoding the site-specific Ho endonucleases. The aneuploid strain, WT4-M, was selected and screened after the tetraploid cells were treated with methyl benzimidazole-2-yl-carbamate to induce loss of mitotic chromosomes. It was found that aneuploid strain WT4-M not only exhibited an increase in ethanol production and osmotic and thermal tolerance, but also an improvement in the sugar-ethanol conversion rate. Notably, WT4-M provided up to 9.8% improvement in ethanol production compared with the control strain. The results demonstrated that the strategy of aneuploidy was valuable for creating yeast strains with better fermentation characteristics.
在酿酒酵母中，通过传统方法控制发酵特性很难改变。在这里，开发了一种新的基因组工程方法，以提高以 300g/L 葡萄糖为碳源的超高浓度发酵中的乙醇产量。该策略涉及在四倍体细胞的基础上构建非整倍体菌株。使用含有 HO 基因的质粒 YCplac33-GHK 构建了四倍体菌株，HO 基因编码定点 Ho 内切酶。在用苯并咪唑-2-基-氨基甲酸甲酯处理四倍体细胞以诱导有丝分裂染色体丢失后，选择和筛选出非整倍体菌株 WT4-M。结果表明，非整倍体菌株 WT4-M 不仅表现出乙醇产量和渗透及热耐受性的提高，而且糖-乙醇转化率也得到改善。值得注意的是，与对照菌株相比，WT4-M 提供了高达 9.8%的乙醇产量提高。结果表明，非整倍体策略对于创造具有更好发酵特性的酵母菌株具有价值。
