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Engineering Escherichia coli for malate production by integrating modular pathway characterization with CRISPRi‐guided multiplexed metabolic tuning
Author(s) -
Gao Cong,
Wang Shihui,
Hu Guipeng,
Guo Liang,
Chen Xiulai,
Xu Peng,
Liu Liming
Publication year - 2018
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.26486
Subject(s) - metabolic engineering , escherichia coli , synthetic biology , metabolic pathway , biochemistry , biology , flux (metallurgy) , bioproduction , modular design , metabolic flux analysis , rational design , computational biology , gene , combinatorial chemistry , chemistry , metabolism , computer science , genetics , organic chemistry , operating system
The application of rational design in reallocating metabolic flux to overproduce desired chemicals is always restricted by the native regulatory network. Here, we demonstrated that in vitro modular pathway optimization combined with in vivo multiplexed combinatorial engineering enables effective characterization of the bottleneck of a complex biosynthetic cascade and improves the output of the engineered pathway. As a proof of concept, we systematically identified the rate‐limiting step of a five‐gene malate biosynthetic pathway by combinatorially tuning the enzyme loads of a reconstituted biocatalytic reaction in a cell‐free system. Using multiplexed CRISPR interference, we subsequently eliminated the metabolic constraints by rationally assigning an optimal gene expression pattern for each pathway module. The present engineered strain Escherichia coli B0013‐47 exhibited a 2.3‐fold increase in malate titer compared with that of the parental strain, with a yield of 0.85 mol/mol glucose in shake‐flask culture and titer of 269 mM (36 g/L) in fed‐batch cultivation. The strategy reported herein represents a powerful method for improving the efficiency of multi‐gene pathways and advancing the success of metabolic engineering.