Metabolic engineering of Corynebacterium glutamicum for efficient production of optically pure (2R,3R)-2,3-butanediol
Journal article, 2022

Background: 2,3-butanediol is an important platform compound which has a wide range of applications, involving in medicine, chemical industry, food and other fields. Especially the optically pure (2R,3R)-2,3-butanediol can be employed as an antifreeze agent and as the precursor for producing chiral compounds. However, some (2R,3R)-2,3-butanediol overproducing strains are pathogenic such as Enterobacter cloacae and Klebsiella oxytoca.
Results: In this study, a (3R)-acetoin overproducing C. glutamicum strain, CGS9, was engineered to produce optically pure (2R,3R)-2,3-butanediol efficiently. Firstly, the gene bdhA from B. subtilis 168 was integrated into strain CGS9 and its expression level was further enhanced by using a strong promoter Psod and ribosome binding site (RBS) with high translation initiation rate, and the (2R,3R)-2,3-butanediol titer of the resulting strain was increased by 33.9%. Then the transhydrogenase gene udhA from E. coli was expressed to provide more NADH for 2,3-butanediol synthesis, which reduced the accumulation of the main byproduct acetoin by 57.2%. Next, a mutant atpG was integrated into strain CGK3, which increased the glucose consumption rate by 10.5% and the 2,3-butanediol productivity by 10.9% in shake-flask fermentation. Through fermentation engineering, the most promising strain CGK4 produced a titer of 144.9 g/L (2R,3R)-2,3-butanediol with a yield of 0.429 g/g glucose and a productivity of 1.10 g/L/h in fed-batch fermentation. The optical purity of the resulting (2R,3R)-2,3-butanediol surpassed 98%.
Conclusions: To the best of our knowledge, this is the highest titer of optically pure (2R,3R)-2,3-butanediol achieved by GRAS strains, and the result has demonstrated that C. glutamicum is a competitive candidate for (2R,3R)-2,3-butanediol production.

Microbial fermentation

Metabolic engineering

Corynebacterium glutamicum

(2R,3R)-2,3-butanediol

Author

Mengyun Kou

Tianjin University

Zhenzhen Cui

Tianjin University

Jing Fu

Chalmers, Biology and Biological Engineering, Systems and Synthetic Biology

Wei Dai

Tianjin University

Zhiwen Wang

Tianjin University

Tao Chen

Tianjin University

Microbial Cell Factories

14752859 (eISSN)

Vol. 21 1 150

Subject Categories

Microbiology

Microbiology in the medical area

Other Industrial Biotechnology

DOI

10.1186/s12934-022-01875-5

PubMed

35879766

More information

Latest update

8/3/2022 8