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Enhanced production of coenzyme Q 10 by self‐regulating the engineered MEP pathway in Rhodobacter sphaeroides
Author(s) -
Lu Wenqiang,
Ye Lidan,
Xu Haoming,
Xie Wenping,
Gu Jiali,
Yu Hongwei
Publication year - 2014
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.25130
Subject(s) - rhodobacter sphaeroides , metabolic engineering , mutant , biochemistry , gene , chemistry , metabolic pathway , enzyme , biosynthesis , cofactor , rhodobacter , protein biosynthesis , regulation of gene expression , microbiology and biotechnology , biology , photosynthesis
Fine‐tuning the expression level of an engineered pathway is crucial for the metabolic engineering of a host toward a desired phenotype. However, most engineered hosts suffer from nonfunctional protein expression, metabolic imbalance, cellular burden or toxicity from intermediates when an engineered pathway is first introduced, which can decrease production of the desired product. To circumvent these obstacles, we developed a self‐regulation system utilizing the trc / tac promoter, LacI q protein and ribosomal binding sites (RBS). With the purpose of improving coenzyme Q 10 (CoQ 10 ) production by increasing the decaprenyl diphosphate supplement, enzymes DXS, DXR, IDI, and IspD were constitutively overexpressed under the control of the trc promoter in Rhodobacter sphaeroides . Then, a self‐regulation system combining a set of RBSs for adjusting the expression of the LacI q protein was applied to tune the expression of the four genes, resulting in improved CoQ 10 production. Finally, another copy of the tac promoter with the UbiG gene (involved in the ubiquinone pathway of CoQ 10 biosynthesis) was introduced into the engineered pathway. By optimizing the expression level of both the upstream and downstream pathway, CoQ 10 production in the mutants was improved up to 93.34 mg/L (7.16 mg/g DCW), about twofold of the wild‐type (48.25 mg/L, 3.24 mg/g DCW). Biotechnol. Bioeng. 2014;111: 761–769. © 2013 Wiley Periodicals, Inc.