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Phosphoenolpyruvate Transporter Enables Targeted Perturbation During Metabolic Analysis of L‐Phenylalanine Production With Escherichia coli
Biotechnology Journal ( IF 3.2 ) Pub Date : 2017-12-28 , DOI: 10.1002/biot.201700611
Julia Tröndle 1 , Christoph Albermann 2 , Michael Weiner 1 , Georg A. Sprenger 2 , Dirk Weuster-Botz 1
Affiliation  

Usually perturbation of the metabolism of cells by addition of substrates is applied for metabolic analysis of production organisms, but perturbation studies are restricted to the endogenous substrates of the cells under study. The goal of this study is to overcome this limitation by making phosphoenolpyruvate (PEP) available for perturbation studies with Escherichia coli producing L‐phenylalanine. A production strain overexpressing a PEP‐transporter variant (UhpT‐D388C) is applied in a standardized fed‐batch production‐process on a 42 L‐scale. Four parallel short‐term perturbation experiments of 20 min are performed with glucose and glycerol as fed‐batch carbon sources after rapid media transition of cells from the production‐process. PEP is added after 9 min and is immediately consumed by the cells with up to 1.5 mmol gCDW−1 h−1. L‐phenylalanine production rates increased by up to 200% after addition of PEP. This clearly indicates an intracellular PEP‐limitation in the L‐phenylalanine production strain under study. Thus, it is shown that overexpressing specific transporters for analytical reasons makes exogenous substrates available as perturbation substrates for metabolic analyses of cells sampled from production‐processes and thereby allows a very targeted perturbation of whole‐cell metabolism.

中文翻译:

磷酸烯醇式丙酮酸转运蛋白在大肠杆菌L-苯丙氨酸生产代谢分析过程中实现靶向扰动

通常,通过添加底物对细胞代谢的扰动被用于生产生物的代谢分析,但是扰动研究仅限于所研究细胞的内源性底物。这项研究的目的是通过使磷酸烯醇丙酮酸(PEP)可用于大肠杆菌的扰动研究来克服这一限制。生产L-苯丙氨酸。将过表达PEP转运蛋白变体(UhpT-D388C)的生产菌株应用于42 L规模的标准化补料分批生产过程。在生产过程中细胞进行快速培养基转化后,以葡萄糖和甘油为补料分批碳源,进行了四个平行的20分钟短期扰动实验。PEP在9分钟后添加,并立即被细胞消耗,直至1.5 mmol g CDW -1  h -1。加入PEP后,L-苯丙氨酸的生产率提高了200%。这清楚地表明了正在研究的L-苯丙氨酸生产菌株中的细胞内PEP限制。因此,表明由于分析原因而过度表达特定转运蛋白,使得外源底物可用作扰动底物,可用于对生产过程中采样的细胞进行代谢分析,从而可以对全细胞代谢进行非常有针对性的扰动。
更新日期:2018-04-29
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