Improved ethanol productivity from lignocellulosic hydrolysates by Escherichia coli with regulated glucose utilization

Microbial Cell Factories

Jinfeng Sun¹  Zhengxiang Wang¹  Kangming Tian²  Xiaoguang Liu²  Zixing Dong²  Jie Wang²  Suren Singh³  Kugenthiren Permaul³  Bernard A. Prior⁴ 

[1]Center for Bioresource and Bioenergy, School of Biotechnology, Jiangnan University

[2]Department of Biological Chemical Engineering, College of Chemical Engineering and Materials Science, Tianjin University of Science and Technology, TEDA

[3]Department of Biotechnology and Food Technology, Durban University of Technology

[4]Department of Microbiology, University of Stellenbosch

关键词: Ethanol;    Thermo-regulated glucose utilization;    Lignocellulosic hydrolysate;    Escherichia coli;   

DOI  :  10.1186/s12934-018-0915-x

来源: DOAJ

【 摘 要 】

Abstract Background Lignocellulosic ethanol could offer a sustainable source to meet the increasing worldwide demand for fuel. However, efficient and simultaneous metabolism of all types of sugars in lignocellulosic hydrolysates by ethanol-producing strains is still a challenge. Results An engineered strain Escherichia coli B0013-2021HPA with regulated glucose utilization, which could use all monosaccharides in lignocellulosic hydrolysates except glucose for cell growth and glucose for ethanol production, was constructed. In E. coli B0013-2021HPA, pta-ackA, ldhA and pflB were deleted to block the formation of acetate, lactate and formate and additional three mutations at glk, ptsG and manZ generated to block the glucose uptake and catabolism, followed by the replacement of the wild-type frdA locus with the ptsG expression cassette under the control of the temperature-inducible λ pR and pL promoters, and the final introduction of pEtac-PA carrying Zymomonas mobilis pdc and adhB for the ethanol pathway. B0013-2021HPA was able to utilize almost all xylose, galactose and arabinose but not glucose for cell propagation at 34 °C and converted all sugars to ethanol at 42 °C under oxygen-limited fermentation conditions. Conclusions Engineered E. coli strain with regulated glucose utilization showed efficient metabolism of mixed sugars in lignocellulosic hydrolysates and thus higher productivity of ethanol production.

【 授权许可】

Unknown