Rational design and analysis of an Escherichia coli strain for high-efficiency tryptophan production
Rational design and analysis of an Escherichia coli strain for high-efficiency tryptophan production
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DOI：
10.1007/s10295-018-2020-x
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发表时间：
2018-05-01
影响因子：
3.4
通讯作者：
Zhang, Dawei
中科院分区：
文献类型：
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作者：
Chen, Yuanye;Liu, Yongfei;Zhang, Dawei
L-色氨酸（L-Trp）是各种生物活性成分的前体，具有很大的药学意义。然而，由于需要几种前体和复杂的调控途径，一个有效的l-trp生产菌株的发展是具有挑战性的。本研究对大肠杆菌（Escherichia coli，E. coli）菌株KW 001被设计为过表达l-trp操纵基因序列（trpEDCBA）和3-脱氧-D-阿拉伯庚酮糖酸-7-磷酸合酶（aroG（fbr））。为了进一步提高l-trp的生产，在阻遏（trpR）和衰减（衰减剂）失活后，删除丙酮酸激酶（pykF）和磷酸转移酶系统HPr（ptsH）以产生菌株KW 006。为了克服相对缓慢的生长和提高葡萄糖的转运速率，通过组合调控葡萄糖激酶（galP）和半乳糖通透酶（glk）的表达来产生菌株KW 018。为了减少乙酸的产生，通过抑制调节磷酸乙酰转移酶（pta）表达来创建菌株KW 023。结果表明，菌株KW 023在5L流加发酵条件下，l-trp的产量为39.7g/L，转化率为16.7%，产率为1.6g/L/h。
l-tryptophan (l-trp) is a precursor of various bioactive components and has great pharmaceutical interest. However, due to the requirement of several precursors and complex regulation of the pathways involved, the development of an efficient l-trp production strain is challenging. In this study, Escherichia coli (E. coli) strain KW001 was designed to overexpress the l-trp operator sequences (trpEDCBA) and 3-deoxy-D-arabinoheptulosonate-7-phosphate synthase (aroG (fbr) ). To further improve the production of l-trp, pyruvate kinase (pykF) and the phosphotransferase system HPr (ptsH) were deleted after inactivation of repression (trpR) and attenuation (attenuator) to produce strain KW006. To overcome the relatively slow growth and to increase the transport rate of glucose, strain KW018 was generated by combinatorial regulation of glucokinase (galP) and galactose permease (glk) expression. To reduce the production of acetic acid, strain KW023 was created by repressive regulation of phosphate acetyltransferase (pta) expression. In conclusion, strain KW023 efficiently produced 39.7 g/L of l-trp with a conversion rate of 16.7% and a productivity of 1.6 g/L/h in a 5 L fed-batch fermentation system.