Application of a Pyruvate-Producing Escherichia coli Strain LAFCPCPt-accBC-aceE: A Case Study for d-Lactate Production
Application of a Pyruvate-Producing Escherichia coli Strain LAFCPCPt-accBC-aceE: A Case Study for d-Lactate Production
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DOI：
10.3390/fermentation6030070
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发表时间：
2020-07
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通讯作者：
K. Wada;T. Fujii;H. Inoue;Hironaga Akita;Tomotake Morita;A. Matsushika
中科院分区：
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作者：
K. Wada;T. Fujii;H. Inoue;Hironaga Akita;Tomotake Morita;A. Matsushika
丙酮酸是发酵过程中产生的基本化学物质之一，是多种化学物质的潜在前体。我们之前报道了一株产丙酮酸的大肠杆菌菌株LAFCPCPt-accBC-aceE (PYR)，该菌株具有应用于丙酮酸工业生产的潜力。在本研究中，利用基于PYR菌株的d-乳酸生产菌株（LAC）评估了PYR菌株生产丙酮酸衍生物的有效性。LAC菌株在T7表达系统的控制下表达保加利亚乳杆菌的d-乳酸脱氢酶编码基因。通过限制曝气和改变d-乳酸脱氢酶编码基因表达的诱导时间，进一步提高了LAC菌株的d-乳酸产量。在综合条件下，LAC菌株产d-乳酸的速度为21.7±1.4 g·L−1，与PYR菌株产丙酮酸的速度（26.1±0.9 g·L−1）相当。这些结果表明，我们已经成功地在LAC菌株中有效地将丙酮酸转化为d-乳酸，表明亲本PYR菌株作为各种化学品生产的基础菌株具有广泛的通用性。
Pyruvate, a potential precursor of various chemicals, is one of the fundamental chemicals produced by the fermentation process. We previously reported a pyruvate-producing Escherichia coli strain LAFCPCPt-accBC-aceE (PYR) that has the potential to be applied to the industrial production of pyruvate. In this study, the availability of the PYR strain for the production of pyruvate-derivative chemicals was evaluated using a d-lactate-producing strain (LAC) based on the PYR strain. The LAC strain expresses a d-lactate dehydrogenase-encoding gene from Lactobacillus bulgaricus under the control of a T7 expression system. The d-lactate productivity of the LAC strain was further improved by limiting aeration and changing the induction period for the expression of d-lactate dehydrogenase-encoding gene expression. Under combined conditions, the LAC strain produced d-lactate at 21.7 ± 1.4 g·L−1, which was compatible with the pyruvate production by the PYR strain (26.1 ± 0.9 g·L−1). These results suggest that we have succeeded in the effective conversion of pyruvate to d-lactate in the LAC strain, demonstrating the wide versatility of the parental PYR strain as basal strain for various chemicals production.