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Improving Succinate Productivity by Engineering a Cyanobacterial CO 2 Concentrating System (CCM) in Escherichia coli
Author(s) -
Xiao Mengyong,
Zhu Xinna,
Bi Changhao,
Ma Yanhe,
Zhang Xueli
Publication year - 2017
Publication title -
biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.144
H-Index - 84
eISSN - 1860-7314
pISSN - 1860-6768
DOI - 10.1002/biot.201700199
Subject(s) - carboxylation , phosphoenolpyruvate carboxykinase , escherichia coli , carbon fixation , metabolic engineering , biochemistry , phosphoenolpyruvate carboxylase , chemistry , carbonic anhydrase , cyanobacteria , rubisco , polyhydroxybutyrate , biology , photosynthesis , bacteria , microbiology and biotechnology , enzyme , gene , catalysis , genetics
Biologically fixation of CO 2 has great potential as a significant carbon source for biosynthesis, which is also a major way to reduce CO 2 accumulation in atmosphere. Phosphoenolpyruvate (PEP) carboxylation is the key step of anaerobic succinate production in Escherichia coli . In this reaction, one mole CO 2 is assimilated with PEP to form oxaloacetate by PEP carboxykinase (PCK). The preferred substrate of PCK is CO 2 , which is very limited in cytoplasm. In this study, the carbon concentration mechanism (CCM) of cyanobacteria was introduced into Escherichia coli to enhance the intracellular inorganic carbon concentration for improving carboxylation velocity. Overexpression of the bicarbonate transporter (BT) or carbonic anhydrase (CA) gene from Synechococcus sp. PCC7002 led to a 22 or 35% increase in succinate titer at 36 h, respectively. The carboxylation rate of PCK increased from 2.46 to 3.92 µmol min −1 mg −1 protein by overexpression of the CA gene. In addition, co‐overexpression of BT and CA genes had a synergetic effect, leading to a 44% increase in succinate titer at 36 h. This work is the first attempt to increase carbon fixation involved in microbial biosynthesis by engineering a biological CO 2 delivery system, which provides new direction and strategies for improving industrial fermentations based on biological CO 2 assimilation pathways.