Introduction of a bacterial acetyl-CoA synthesis pathway improves lactic acid production in Saccharomyces cerevisiae.
Introduction of a bacterial acetyl-CoA synthesis pathway improves lactic acid production in Saccharomyces cerevisiae.
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DOI：
10.1016/j.ymben.2015.09.006
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发表时间：
2016-05
影响因子：
8.4
通讯作者：
Ji-Yoon Song;Joon-Song Park;Chang Duk Kang;Hwa-Young Cho;D. Yang;Seunghyung Lee;K. Cho
中科院分区：
文献类型：
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作者：
Ji-Yoon Song;Joon-Song Park;Chang Duk Kang;Hwa-Young Cho;D. Yang;Seunghyung Lee;K. Cho
通过表达异源乳酸脱氢酶（LDH）基因，同时减弱几个关键途径基因，包括甘油-3-磷酸脱氢酶1（GPD 1）和细胞色素-c氧化还原酶2（CYB 2），来改造耐酸酿酒酵母以产生乳酸。为了进一步提高乳酸的产量，通过破坏丙酮酸脱羧酶1（PDC 1）和乙醇脱氢酶1（ADH 1）基因来减弱乙醇生产途径。尽管乳酸产率增加，但由于缺乏ADH 1，生长速率和葡萄糖消耗速率严重降低，导致整体生产率显著降低。在Δ adh 1细胞中，乙酰辅酶A（生物学适用成分的关键前体）的水平可能不足以维持正常细胞生长。为了增加乙酰辅酶A的细胞供应，我们将细菌乙酰化乙醛脱氢酶（A-ALD）基因（EC 1.2.1.10）导入乳酸产生菌S。啤酒。大肠杆菌衍生的A-ALD基因mhpFandeutE在酵母中表达并有效地补充了减弱的乙醛脱氢酶（ALD）/乙酰辅酶A合成酶（ACS）途径。该工程菌具有异源乙酰辅酶A合成途径，表现出较高的葡萄糖消耗速率和较高的乳酸发酵产率。在生物反应器中进行补料分批发酵，乳酸产量达到142 g/L，产量为0.89 g/g，生产能力为3.55 g L−1h− 1。这项研究表明了一种新的方法，提高生产力的乳酸代谢工程的乙酰辅酶A的生物合成途径在酵母。
Acid-tolerant Saccharomyces cerevisiae was engineered to produce lactic acid by expressing heterologous lactate dehydrogenase (LDH) genes, while attenuating several key pathway genes, including glycerol-3-phosphate dehydrogenase1 (GPD1) and cytochrome-c oxidoreductase2 (CYB2). In order to increase the yield of lactic acid further, the ethanol production pathway was attenuated by disrupting the pyruvate decarboxylase1 (PDC1) and alcohol dehydrogenase1 (ADH1) genes. Despite an increase in lactic acid yield, severe reduction of the growth rate and glucose consumption rate owing to the absence of ADH1 caused a considerable decrease in the overall productivity. In Δadh1cells, the levels of acetyl-CoA, a key precursor for biologically applicable components, could be insufficient for normal cell growth. To increase the cellular supply of acetyl-CoA, we introduced bacterial acetylating acetaldehyde dehydrogenase (A-ALD) enzyme (EC 1.2.1.10) genes into the lactic acid-producingS. cerevisiae. Escherichia coli-derived A-ALD genes,mhpFandeutE,were expressed and effectively complemented the attenuated acetaldehyde dehydrogenase (ALD)/acetyl-CoA synthetase (ACS) pathway in the yeast. The engineered strain, possessing a heterologous acetyl-CoA synthetic pathway, showed an increased glucose consumption rate and higher productivity of lactic acid fermentation. The production of lactic acid was reached at 142 g/L with production yield of 0.89 g/g and productivity of 3.55 g L−1h−1under fed-batch fermentation in bioreactor. This study demonstrates a novel approach that improves productivity of lactic acid by metabolic engineering of the acetyl-CoA biosynthetic pathway in yeast.