title: Systematic metabolic engineering of Escherichia coli for high-yield production of fuel bio-chemical 2,3-butanediol.
abstract: The production of biofuels by recombinant Escherichia coli is restricted by the toxicity of the products. 2,3-Butanediol (2,3-BD), a platform and fuel bio-chemical with low toxicity to microbes, could be a promising alternative for biofuel production. However, the yield and productivity of 2,3-BD produced by recombinant E. coli strains are not sufficient for industrial scale fermentation. In this work, the production of 2,3-BD by recombinant E. coli strains was optimized by applying a systematic approach. 2,3-BD biosynthesis gene clusters were cloned from several native 2,3-BD producers, including Bacillus subtilis, Bacillus licheniformis, Klebsiella pneumoniae, Serratia marcescens, and Enterobacter cloacae, inserted into the expression vector pET28a, and compared for 2,3-BD synthesis. The recombinant strain E. coli BL21/pETPT7-EcABC, carrying the 2,3-BD pathway gene cluster from Enterobacter cloacae, showed the best ability to synthesize 2,3-BD. Thereafter, expression of the most efficient gene cluster was optimized by using different promoters, including PT7, Ptac, Pc, and Pabc. E. coli BL21/pET-RABC with Pabc as promoter was superior in 2,3-BD synthesis. On the basis of the results of biomass and extracellular metabolite profiling analyses, fermentation conditions, including pH, agitation speed, and aeration rate, were optimized for the efficient production of 2,3-BD. After fed-batch fermentation under the optimized conditions, 73.8g/L of 2,3-BD was produced by using E. coli BL21/pET-RABC within 62h. The values of both yield and productivity of 2,3-BD obtained with the optimized biological system are the highest ever achieved with an engineered E. coli strain. In addition to the 2,3-BD production, the systematic approach might also be used in the production of other important chemicals through recombinant E. coli strains.
authors: State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, People׳s Republic of China.
authors: Youqiang
authors: Y
authors: Xu
authors: State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, People׳s Republic of China.
authors: Haipei
authors: H
authors: Chu
authors: State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, People׳s Republic of China.
authors: Chao
authors: C
authors: Gao
authors: State Key Laboratory of Microbial Metabolism & School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People׳s Republic of China.
authors: Fei
authors: F
authors: Tao
authors: State Key Laboratory of Microbial Metabolism & School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People׳s Republic of China.
authors: Zikang
authors: Z
authors: Zhou
authors: State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, People׳s Republic of China.
authors: Kun
authors: K
authors: Li
authors: State Key Laboratory of Microbial Metabolism & School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People׳s Republic of China.
authors: Lixiang
authors: L
authors: Li
authors: State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, People׳s Republic of China. Electronic address: macq@sdu.edu.cn.
authors: Cuiqing
authors: C
authors: Ma
authors: State Key Laboratory of Microbial Metabolism & School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People׳s Republic of China. Electronic address: pingxu@sjtu.edu.cn.
authors: Ping
authors: P
authors: Xu
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D056804:Biofuels; D018533:Biomass; D002072:Butylene Glycols / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005810:Multigene Family; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D056804:Biofuels; D002072:Butylene Glycols; D011994:Recombinant Proteins; C026978:2,3-butylene glycol
keywords: 2,3-Butanediol; Biofuel; Escherichia coli; Fermentation; Metabolic engineering; Promoter