Metabolic engineering of Escherichia coli for the production of 1-propanol

• Published in: Metabolic engineering Vol. 14; no. 5; pp. 477 - 486
• Main Authors: Jun Choi, Yong, Hwan Park, Jin, Yong Kim, Tae, Yup Lee, Sang
• Format: Journal Article
• Language: English
• Published: Belgium Elsevier Inc 01.09.2012
• Subjects: 1-propanol; 1-Propanol - metabolism; 2-ketobutyrate; Acetate kinase; Acetate Kinase - genetics; Acetate Kinase - metabolism; Aerobic conditions; Aerobiosis; Escherichia coli; Escherichia coli - enzymology; Escherichia coli - genetics; Escherichia coli - growth & development; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Fed-batch culture; Feedback; Glucose; Glycerol; In silico metabolic flux analysis; l-threonine; Metabolic Engineering; Metabolic pathways; Oxo-Acid-Lyases - genetics; Oxo-Acid-Lyases - metabolism; Phosphotransferases (Carboxyl Group Acceptor) - genetics; Phosphotransferases (Carboxyl Group Acceptor) - metabolism; Propionic acid; rpoS protein; Sigma factor; stationary phase; Threonine dehydratase; Threonine Dehydratase - genetics; Threonine Dehydratase - metabolism; In silico metabolic flux analysis; Glycerol; l-threonine; 1-propanol; 2-ketobutyrate; Escherichia coli
• ISSN: 1096-7176; 1096-7184
• DOI: 10.1016/j.ymben.2012.07.006

An engineered Escherichia coli strain that produces 1-propanol under aerobic condition was developed based on an l-threonine-overproducing E. coli strain. First, a feedback resistant ilvA gene encoding threonine dehydratase was introduced and the competing metabolic pathway genes were deleted. Further engineering was performed by overexpressing the cimA gene encoding citramalate synthase and the ackA gene encoding acetate kinase A/propionate kinase II, introducing a modified adhE gene encoding an aerobically functional AdhE, and by deleting the rpoS gene encoding the stationary phase sigma factor. Fed-batch culture of the final engineered strain harboring pBRthrABC-tac-cimA-tac-ackA and pTacDA-tac-adhEmut allowed production of 10.8gL−1 of 1-propanol with the yield and productivity of 0.107gg−1 and 0.144gL−1h−1, respectively, from 100gL−1 of glucose, and 10.3gL−1 of 1-propanol with the yield and productivity of 0.259gg−1 and 0.083gL−1h−1, respectively, from 40gL−1 glycerol. ► 1-propanol producing E. coli strain was developed by metabolic engineering. ► Use of aerobically functional AdhE allowed 1-propanol production under aerobic condition. ► Overexpression of cimA and deletion of rpoS increased 1-propanol production. ► The final engineered strain produced more than 10gL−1 of 1-propanol from glucose or glycerol.