Abstract：
:Vitamin B12 is a crucial fine chemical that is widely used in the pharmaceutical, food and chemical industries, and its production solely dependents on microbial fermentation. We previously constructed an artificial vitamin B12 biosynthesis pathway in Escherichia coli, but the yield of the engineered strains was low. Here, we removed metabolic bottlenecks of the vitamin B12 biosynthesis pathway in engineered E. coli strains. After screening cobB genes from different sources, optimizing the expression of cobN and customizing the ribosome binding sites of cobS and cobT, the vitamin B12 yield increased to 152.29 μg/g dry cell weight (DCW). Optimization of the downstream module, which converts co(II)byrinic acid a,c-diamide into adenosylcobinamide phosphate, elevated the vitamin B12 yield to 249.04 μg/g DCW. A comparison of a variety of equivalent components indicated that glucose and corn steep liquor are optimal carbon and nitrogen sources, respectively. Finally, an orthogonal array design was applied to determine the optimal concentrations of glucose and nitrogen sources including corn steep liquor and yeast extract, through which a vitamin B12 yield of 530.29 μg/g DCW was obtained. The metabolic modifications and optimization of fermentation conditions achieved in this study offer a basis for further improving vitamin B12 production in E. coli and will hopefully accelerate its industrial application.
journal_name
Bioprocess Biosyst Engjournal_title
Bioprocess and biosystems engineeringauthors
Li D,Fang H,Gai Y,Zhao J,Jiang P,Wang L,Wei Q,Yu D,Zhang Ddoi
10.1007/s00449-020-02355-zsubject
Has Abstractpub_date
2020-10-01 00:00:00pages
1735-1745issue
10eissn
1615-7591issn
1615-7605pii
10.1007/s00449-020-02355-zjournal_volume
43pub_type
杂志文章abstract：:Polyhydroxyalkanoates (PHAs) are biological plastics that are sustainable alternative to synthetic ones. Numerous microorganisms have been identified as PHAs producers. They store PHAs as cellular inclusions to use as an energy source backup. They can be produced in shake flasks and in bioreactors under defined fermen...
journal_title：Bioprocess and biosystems engineering
pub_type： 杂志文章,评审
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journal_title：Bioprocess and biosystems engineering
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journal_title：Bioprocess and biosystems engineering
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更新日期：2005-08-01 00:00:00
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journal_title：Bioprocess and biosystems engineering
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journal_title：Bioprocess and biosystems engineering
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journal_title：Bioprocess and biosystems engineering
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