Construction of Escherichia coli strains producing L-serine from glucose.

Yu Li, Gu-Kui Chen, Xin-Wei Tong, Hui-Tu Zhang, Xiao-Guang Liu, Yi-Han Liu, Fu-Ping Lu

Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, National Engineering Laboratory for Industrial Enzymes, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China.

Biotechnology letters 2012 Aug

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L-Serine is usually produced from glycine. We have genetically engineered Escherichia coli to produce L-serine from glucose intracellularly. D-3-Phosphoglycerate dehydrogenase (PGDH, EC 1.1.1.95) in E. coli catalyzes the first committed step in L-serine formation but is inhibited by L-serine. To overcome this feedback inhibition, both the His(344) and Asn(346) residues of PGDH were converted to alanine and the mutated PGDH (PGDH(dr)) became insensitive to L-serine. However, overexpression of PGDH(dr) gave no significant increase of L-serine accumulation but, when L-serine deaminase genes (sdaA, sdaB and tdcG) were deleted, serine accumulated: (1) deletion of sdaA gave up to 0.03 mmol L-serine/g; (2) deletion of both sdaA and sdaB accumulated L-serine up to 0.09 mmol/g; and (3) deletion of sdaA, sdaB and tdcG gave up to 0.13 mmol L-serine/g cell dry wt.

Citation

Yu Li, Gu-Kui Chen, Xin-Wei Tong, Hui-Tu Zhang, Xiao-Guang Liu, Yi-Han Liu, Fu-Ping Lu. Construction of Escherichia coli strains producing L-serine from glucose. Biotechnology letters. 2012 Aug;34(8):1525-30