Engineering a wild-type diploid Saccharomyces cerevisiae strain for second-generation bioethanol production.
Engineering a wild-type diploid Saccharomyces cerevisiae strain for second-generation bioethanol production.
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工程化野生型二倍体酿酒酵母菌株用于第二代生物乙醇生产
DOI：
10.1186/s40643-016-0126-4
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发表时间：
2016
影响因子：
4.6
通讯作者：
Bao X
中科院分区：
文献类型：
--
作者：
Li H;Shen Y;Wu M;Hou J;Jiao C;Li Z;Liu X;Bao X
以木质纤维素材料为原料的第二代生物乙醇的经济生产必须面临以下两个问题：木糖与葡萄糖共发酵以及增强菌株对木质纤维素抑制剂的耐受性。在前期研究的基础上，以具有鲁棒性和良好木糖代谢遗传背景的野生型二倍体酿酒酵母菌株BSIF为基础，构建高效木糖发酵工业菌株。研究了所得菌株在含糖和水解产物的培养基发酵中的性能。以下两个新的异源基因被整合到底盘细胞的基因组中：突变体 MGT05196 N360F，它编码木糖特异性、葡萄糖不敏感的转运蛋白，源自 Meyerozyma guilliermondii 转运蛋白基因 MGT05196，以及 Ru-xylA（其中 Ru 代表瘤胃），它编码 酿酒酵母中具有较高活性的木糖异构酶 (XI)。此外，还进行了内源性修饰，包括木酮糖激酶 Xks1p 和非氧化 PPP（磷酸戊糖途径）的过量产生，以及醛糖还原酶 Gre3p 和碱性磷酸酶 Pho13p 的失活。这些合理设计的基因改造，结合木糖和SECS液（蒸汽爆炸玉米秸秆浸出液）的交替适应性进化，产生了最终菌株LF1，它具有优异的木糖发酵能力和增强的抑制剂抗性。以木糖为唯一碳源时，LF1 的木糖比消耗率高达 1.089 g g−1 h−1。而且，其对木糖和葡萄糖的高度同步利用尤为显着； 12 h内77.6%的木糖与葡萄糖一起被消耗，乙醇产量为0.475 g g−1，超过理论产量的93%。此外，LF1 在两种不同木质纤维素水解产物的发酵中表现良好。菌株LF1高效、同步地共发酵葡萄糖和木糖。这一结果凸显了LF1在第二代生物乙醇实际生产中的巨大潜力。本文的在线版本 (doi:10.1186/s40643-016-0126-4) 包含补充材料，可供授权用户使用。
The cost-effective production of second-generation bioethanol, which is made from lignocellulosic materials, has to face the following two problems: co-fermenting xylose with glucose and enhancing the strain’s tolerance to lignocellulosic inhibitors. Based on our previous study, the wild-type diploid Saccharomyces cerevisiae strain BSIF with robustness and good xylose metabolism genetic background was used as a chassis for constructing efficient xylose-fermenting industrial strains. The performance of the resulting strains in the fermentation of media with sugars and hydrolysates was investigated. The following two novel heterologous genes were integrated into the genome of the chassis cell: the mutant MGT05196 N360F, which encodes a xylose-specific, glucose-insensitive transporter and is derived from the Meyerozyma guilliermondii transporter gene MGT05196, and Ru-xylA (where Ru represents the rumen), which encodes a xylose isomerase (XI) with higher activity in S. cerevisiae. Additionally, endogenous modifications were also performed, including the overproduction of the xylulokinase Xks1p and the non-oxidative PPP (pentose phosphate pathway), and the inactivation of the aldose reductase Gre3p and the alkaline phosphatase Pho13p. These rationally designed genetic modifications, combined with alternating adaptive evolutions in xylose and SECS liquor (the leach liquor of steam-exploding corn stover), resulted in a final strain, LF1, with excellent xylose fermentation and enhanced inhibitor resistance. The specific xylose consumption rate of LF1 reached as high as 1.089 g g−1 h−1 with xylose as the sole carbon source. Moreover, its highly synchronized utilization of xylose and glucose was particularly significant; 77.6% of xylose was consumed along with glucose within 12 h, and the ethanol yield was 0.475 g g−1, which is more than 93% of the theoretical yield. Additionally, LF1 performed well in fermentations with two different lignocellulosic hydrolysates. The strain LF1 co-ferments glucose and xylose efficiently and synchronously. This result highlights the great potential of LF1 for the practical production of second-generation bioethanol. The online version of this article (doi:10.1186/s40643-016-0126-4) contains supplementary material, which is available to authorized users.