Metabolic engineering of a synergistic pathway for n-butanol production in Saccharomyces cerevisiae.
Metabolic engineering of a synergistic pathway for n-butanol production in Saccharomyces cerevisiae.
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DOI：
10.1038/srep25675
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发表时间：
2016-05-10
影响因子：
4.6
通讯作者：
Zhao H
中科院分区：
文献类型：
--
作者：
Shi S;Si T;Liu Z;Zhang H;Ang EL;Zhao H
正丁醇作为一种先进的燃料或平台化学品有几个有利的特性。生物基正丁醇的生产对可持续化学工业的发展越来越重要。正丁醇的合成可以通过多种代谢途径实现。本文报道了酿酒酵母的代谢工程，通过内源性苏氨酸途径和引入的柠檬酸盐途径协同生产正丁醇。首先，我们对内源性苏氨酸途径进行了表征和优化；然后，引入柠檬酸合酶（CimA）介导的途径，构建协同通路；接下来，通过增加先前鉴定的相关基因的过表达来优化协同途径；同时，过表达酮酸脱羧酶（KDC）和醇脱氢酶（ADH）也提高了正丁醇的产量。将这些策略与LEU1（2拷贝）、LEU4、LEU2（2拷贝）、LEU5、CimA、NFS1、ADH7和ARO10*的共表达结合后，我们获得了最终工程菌株的正丁醇产量为835 mg/L，比初始菌株增加了近7倍。此外，该产品的滴度是有史以来在酵母中报道的最高滴度的3倍。因此，工程酵母菌株代表了正丁醇生产的一个有前途的替代平台。
n-Butanol has several favourable properties as an advanced fuel or a platform chemical. Bio-based production of n-butanol is becoming increasingly important for sustainable chemical industry. Synthesis of n-butanol can be achieved via more than one metabolic pathway. Here we report the metabolic engineering of Saccharomyces cerevisiae to produce n-butanol through a synergistic pathway: the endogenous threonine pathway and the introduced citramalate pathway. Firstly, we characterized and optimized the endogenous threonine pathway; then, a citramalate synthase (CimA) mediated pathway was introduced to construct the synergistic pathway; next, the synergistic pathway was optimized by additional overexpression of relevant genes identified previously; meanwhile, the n-butanol production was also improved by overexpression of keto-acid decarboxylases (KDC) and alcohol dehydrogenase (ADH). After combining these strategies with co-expression of LEU1 (two copies), LEU4, LEU2 (two copies), LEU5, CimA, NFS1, ADH7 and ARO10*, we achieved an n-butanol production of 835 mg/L in the final engineered strain, which is almost 7-fold increase compared to the initial strain. Furthermore, the production showed a 3-fold of the highest titer ever reported in yeast. Therefore, the engineered yeast strain represents a promising alternative platform for n-butanol production.