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- Title
Enhancement of medium-chain-length polyhydroxyalkanoates biosynthesis from glucose by metabolic engineering in Pseudomonas mendocina.
- Authors
Wang, Yuanyuan; Zhao, Fengjie; Fan, Xu; Wang, Shufang; Song, Cunjiang
- Abstract
Objectives: To enhance the biosynthesis of medium-chain-length polyhydroxyalkanoates (PHA) from glucose in Pseudomonas mendocina NK-01, metabolic engineering strategies were used to block or enhance related pathways. Results: Pseudomonas mendocina NK-01 produces PHA from glucose. Besides the alginate oligosaccharide biosynthetic pathway proved by our previous study, UDP- d-glucose and dTDP- l-rhamnose biosynthetic pathways were identified. These might compete for glucose with the PHA biosynthesis. First, the alg operon, galU and rmlC gene were deleted one by one, resulting in NK-U-1(∆ alg), NK-U-2 (∆ alg∆ galU), NK-U-3( alg∆ galU∆ rmlC). After fermentation for 36 h, the cell dry weight (CDW) and PHA production of these strains were determined. Compared with NK-U: 1) NK-U-1 produced elevated CDW (from 3.19 ± 0.16 to 3.5 ± 0.11 g/l) and equal PHA (from 0.78 ± 0.06 to 0.79 ± 0.07 g/l); 2) NK-U-2 produced more CDW (from 3.19 ± 0.16 to 3.55 ± 0.23 g/l) and PHA (from 0.78 ± 0.06 to 1.05 ± 0.07 g/l); 3) CDW and PHA dramatically decreased in NK-U-3 (1.53 ± 0.21 and 0.41 ± 0.09 g/l, respectively). Additionally, the phaG gene was overexpressed in strain NK-U-2. Although CDW of NK-U-2/ phaG decreased to 1.29 ± 0.2 g/l, PHA titer (%CDW) significantly increased from 24.5 % up to 51.2 %. Conclusion: The PHA biosynthetic pathway was enhanced by blocking branched metabolic pathways in combination with overexpressing phaG gene.
- Subjects
POLYHYDROXYALKANOATES synthesis; GLUCOSE synthesis; BIOSYNTHESIS; OLIGOSACCHARIDES; PSEUDOMONAS; RHAMNOSE; THIOESTERASE
- Publication
Biotechnology Letters, 2016, Vol 38, Issue 2, p313
- ISSN
0141-5492
- Publication type
Article
- DOI
10.1007/s10529-015-1980-4