Fitness analysis between the L-sorbosone dehydrogenase modules and Ketogulonigenium vulgare chassis.

Si Chen; Nan Jia; Mingzhu Ding; Yingjin Yuan

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Fitness analysis between the L-sorbosone dehydrogenase modules and Ketogulonigenium vulgare chassis.

Author: Si CHEN ¹ ; Nan JIA ¹ ; Mingzhu DING ¹ ; Yingjin YUAN ¹
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1. Key Laboratory of Systems Bio-engineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
Publication Type:Journal Article
Keywords: Ketogulonigenium vulgare; L-sorbosone dehydrogenase; adaptive evolution; fitness; mixed culture system
MeSH: Aldehyde Oxidoreductases; genetics; metabolism; Ascorbic Acid; Bacillus; Bacterial Proteins; genetics; metabolism; Coculture Techniques; Fermentation; Industrial Microbiology; Microorganisms, Genetically-Modified; Rhodobacteraceae; enzymology; genetics; Sugar Acids; metabolism
From: Chinese Journal of Biotechnology 2016;32(9):1224-1232
CountryChina
Language:Chinese
Abstract: Ketogulonigenium vulgare is an acid-producing strain in the process of two-step vitamin C fermentation. L-sorbosone dehydrogenase (SNDH) is one of the key enzymes during the biosynthesis of 2-keto-L-gulonic acid (2-KGA), the precursor of vitamin C. However, the catalytic mechanism of SNDH is unclear. According to the whole genome sequencing of K. vulgare, two genes encoding sorbosone dehydrogenases, one derived from the chromosome (named as sndhg) and one from plasmid (named as sndhp), were introduced into an industrial strain K. vulgare. The overexpression of gene sndhg had hardly effect on 2-KGA production, and the overexpression of gene sndhp produced an obvious byproduct in the fermentation broth. Combinational expression of sndhg/sndhp with pqqA (obtaining sndhg-pqqA and sndhp-pqqA modules) in K. vulgare resulted in the similar fermentation phenotype to two previous strains. After serial sub-cultivation of co-cultured Bacillus endophyticus with each engineered K. vulgare for 50 d, the conversion rate of 2-KGA increased by 15.4%, 179%, 0.65% and 125% compared with that of the parental K. vulgare with B. endophyticus. This study shows that adaptive evolution of microbial consortium is an effective strategy to increase the fitness between functional modules and chassis, thus quickly getting better strains for production of 2-KGA.