Metabolic engineering of Escherichia coli for the production of riboflavin

Microbial Cell Factories

Research

Yifan Li¹  Zhiwen Wang¹  Zhenquan Lin¹  Zhibo Xu¹  Tao Chen¹  Xueming Zhao¹ 

[1] Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, 300072, Tianjin, China;Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, 300072, Tianjin, China;Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, 300072, Tianjin, China;

关键词: Riboflavin;    Flavin Adenine Dinucleotide;    Minimal Salt Medium;    Riboflavin Production;    Riboflavin Biosynthesis;   

DOI  :  10.1186/s12934-014-0104-5

 received in 2014-05-14, accepted in 2014-07-09,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundRiboflavin (vitamin B2), the precursor of the flavin cofactors flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), is used commercially as an animal feed supplement and food colorant. E. coli is a robust host for various genetic manipulations and has been employed for efficient production of biofuels, polymers, amino acids, and bulk chemicals. Thus, the aim of this study was to understand the metabolic capacity of E. coli for the riboflavin production by modification of central metabolism, riboflavin biosynthesis pathway and optimization of the fermentation conditions.ResultsThe basic producer RF01S, in which the riboflavin biosynthesis genes ribABDEC from E. coli were overexpressed under the control of the inducible trc promoter, could accumulate 229.1 mg/L of riboflavin. Further engineering was performed by examining the impact of expression of zwf (encodes glucose 6-phosphate dehydrogenase) and gnd (encodes 6-phosphogluconate dehydrogenase) from Corynebacterium glutamicum and pgl (encodes 6-phosphogluconolactonase) from E. coli on riboflavin production. Deleting pgi (encodes glucose-6-phosphate isomerase) and genes of Entner-Doudoroff (ED) pathway successfully redirected the carbon flux into the oxidative pentose phosphate pathway, and overexpressing the acs (encodes acetyl-CoA synthetase) reduced the acetate accumulation. These modifications increased riboflavin production to 585.2 mg/L. By further modulating the expression of ribF (encodes riboflavin kinase) for reducing the conversion of riboflavin to FMN in RF05S, the final engineering strain RF05S-M40 could produce 1036.1 mg/L riboflavin in LB medium at 37°C. After optimizing the fermentation conditions, strain RF05S-M40 produced 2702.8 mg/L riboflavin in the optimized semi-defined medium, which was a value nearly 12-fold higher than that of RF01S, with a yield of 137.5 mg riboflavin/g glucose.ConclusionsThe engineered strain RF05S-M40 has the highest yield among all reported riboflavin production strains in shake flask culture. This work collectively demonstrates that E. coli has a potential to be a microbial cell factory for riboflavin bioproduction.

【 授权许可】

Unknown   
© Lin et al.; licensee BioMed Central 2014. his is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.