Enhanced production of coenzyme Q10 by self‐regulating the engineered MEP pathway in Rhodobacter sphaeroides. Issue 4 (31st October 2013)

• Record Type: Journal Article
• Authors: Lu, Wenqiang; Ye, Lidan; Xu, Haoming; Xie, Wenping; Gu, Jiali; Yu, Hongwei
• Is Part Of: Biotechnology and bioengineering. Volume 111:Issue 4(2014:Apr.)
• Page Start: 761
• Page End: 769
• Publication Date: 2013-10-31
• Subjects: Biotechnology -- Periodicals; Bioengineering -- Periodicals; 660.6
• DOI: 10.1002/bit.25130
• Languages: English
• ISSNs: 0006-3592

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>ABSTRACT</title> <sec id="bit25130-sec-0001" sec-type="section"> <p>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 <italic>trc</italic>/<italic>tac</italic> promoter, LacI<sup>q</sup> protein and ribosomal binding sites (RBS). With the purpose of improving coenzyme Q<sub>10</sub> (CoQ<sub>10</sub>) production by increasing the decaprenyl diphosphate supplement, enzymes DXS, DXR, IDI, and IspD were constitutively overexpressed under the control of the <italic>trc</italic> promoter in <italic>Rhodobacter sphaeroides</italic>. Then, a self‐regulation system combining a set of RBSs for adjusting the expression of the LacI<sup>q</sup> protein was applied to tune the expression of the four genes, resulting in improved CoQ<sub>10</sub> production. Finally, another copy of the <italic>tac</italic> promoter with the UbiG gene (involved in the ubiquinone pathway of CoQ<sub>10</sub> biosynthesis) was introduced into the engineered pathway. By optimizing the expression level of both the upstream and downstream pathway, CoQ<sub>10</sub> 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.</p> </sec> </abstract>