Saccharomyces cerevisiae is a promising candidate for production of organic acids as it is more tolerant to these acids than the prokaryotes. However, the large-scale production of organic acids from lignocellulosic biomass is limited by their accumulation in the growth medium and inability of xylose fermentation by S. cerevisiae. Here we showed that high intracellular spermidine (SPD) contents confers enhanced tolerance to lactic, succinic, and malic acids in S. cerevisiae. Specifically, in the presence of 20 g/L malic acid, the maximum specific growth rate and dry cell weight of a S. cerevisiae with two fold higher SPD content were 40% and 36% higher than those of the control strain. When a xylose assimilation pathway was introduced into an engineered strain with high SPD content, the resulting S. cerevisiae strain exhibited 23∼47% higher xylose consumption rate and 6∼16% higher ethanol productivity than those of the control strain during the four times of repeated-batch fermentations using a mixture of glucose and xylose as carbon sources. These results suggest that the strain developed in this study would serve as a platform strain for production of organic acids.

酿酒酵母是生产有机酸的有前途的候选者，因为它比原核生物更能耐受这些酸。然而，由木质纤维素生物质大规模生产有机酸受到其在生长培养基中的积累以及酿酒酵母无法木糖发酵的限制。在这里，我们显示出高细胞内亚精胺（SPD）含量赋予酿酒酵母对乳酸，琥珀酸和苹果酸的增强耐受性。具体而言，在20 g / L苹果酸的存在下，酿酒酵母的最大比生长速率和干细胞重量SPD含量高2倍的大豆分别比对照菌株高40％和36％。当木糖同化途径被引入到具有高SPD含量的工程菌株中时，所得到的酿酒酵母菌株在4倍于5倍的发酵过程中，木糖的消耗率比对照菌株高23〜47％，乙醇生产率高6〜16％。使用葡萄糖和木糖的混合物作为碳源的间歇式发酵。这些结果表明，在这项研究中开发的菌株将作为生产有机酸的平台菌株。