Genetic engineering to enhance the Ehrlich pathway and alter carbon flux for increased isobutanol production from glucose by Saccharomyces cerevisiae
Genetic engineering to enhance the Ehrlich pathway and alter carbon flux for increased isobutanol production from glucose by Saccharomyces cerevisiae
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DOI：
10.1016/j.jbiotec.2012.01.022
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发表时间：
2012-05-31
影响因子：
4.1
通讯作者：
Kondo, Akihiko
中科院分区：
文献类型：
--
作者：
Kondo, Takashi;Tezuka, Hironori;Kondo, Akihiko
工程菌生产高级醇受到了极大的关注。发芽酵母酿酒酵母具有较大的生产高级醇的潜力，因为它具有天然合成杂醇醇的能力，此外还具有对低pH的稳健性和耐受性。然而，由于其自然生产率并不显著，我们考虑了一种基因工程策略来提高与缬氨酸生物合成有关的支链高级醇异丁醇的产量。最初，我们在酿酒酵母中过表达了2-酮酸脱羧酶(KDC)和乙醇脱氢酶(ADH)，以增强Ehrlich途径的内源活性。然后，我们过表达了催化缬氨酸合成途径第一步的Ilv2，并删除了编码主要的丙酮酸脱羧酶的PDC1基因，目的是通过丙酮酸改变丰富的乙醇通量。通过这些工程步骤，随着培养条件的改变，酿酒酵母的异丁醇效价提高了13倍，从11 mg/L提高到143 mg/L，产糖量为6.6 mg/g葡萄糖，高于以往报道的酿酒酵母产量。(C)2012爱思唯尔B.V.保留所有权利。
The production of higher alcohols by engineered bacteria has received significant attention. The budding yeast, Saccharomyces cerevisiae, has considerable potential as a producer of higher alcohols because of its capacity to naturally fabricate fusel alcohols, in addition to its robustness and tolerance to low pH. However, because its natural productivity is not significant, we considered a strategy of genetic engineering to increase production of the branched-chain higher alcohol isobutanol, which is involved in valine biosynthesis. Initially, we overexpressed 2-keto acid decarboxylase (KDC) and alcohol dehydrogenase (ADH) in S. cerevisiae to enhance the endogenous activity of the Ehrlich pathway. We then overexpressed Ilv2, which catalyzes the first step in the valine synthetic pathway, and deleted the PDC1 gene encoding a major pyruvate decarboxylase with the intent of altering the abundant ethanol flux via pyruvate. Through these engineering steps, along with modification of culture conditions, the isobutanol titer of S. cerevisiae was elevated 13-fold, from 11 mg/l to 143 mg/l, and the yield was 6.6 mg/g glucose, which is higher than any previously reported value for S. cerevisiae. (C) 2012 Elsevier B.V. All rights reserved.