1. Biosynthesis and characterization of poly(3-hydroxydodecanoate) by β-oxidation inhibited mutant of Pseudomonas entomophila L48.
- Author
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Chung AL, Jin HL, Huang LJ, Ye HM, Chen JC, Wu Q, and Chen GQ
- Subjects
- 3-Hydroxyacyl CoA Dehydrogenases deficiency, 3-Hydroxyacyl CoA Dehydrogenases genetics, Acetyl-CoA C-Acetyltransferase deficiency, Acetyl-CoA C-Acetyltransferase genetics, Acetyl-CoA C-Acyltransferase deficiency, Acetyl-CoA C-Acyltransferase genetics, Bacterial Proteins genetics, Bioreactors, Chromatography, Gas, Crystallization, Fatty Acids metabolism, Fermentation, Gene Deletion, Magnetic Resonance Spectroscopy, Organisms, Genetically Modified growth & development, Oxidation-Reduction, Pseudomonas genetics, Bacterial Proteins metabolism, Industrial Microbiology methods, Organisms, Genetically Modified genetics, Polyhydroxyalkanoates biosynthesis, Polyhydroxyalkanoates genetics, Polyhydroxyalkanoates isolation & purification, Pseudomonas enzymology
- Abstract
A medium-chain-length (MCL) polyhydroxyalkanoates (PHAs) producer Pseudomonas entomophila L48 was investigated for microbial production of 3-hydroxydodecanote homopolymer. Pseudomonas entomophila L48 was found to produce MCL PHA consisting of 3-hydroxyhexanoate (3HHx), 3-hydroxyoctanoate (3HO), 3-hydroxydecanoate (3HD), and 3-hydroxydodecanoate (3HDD) from related carbon sources fatty acids. In this study, some of the genes encoding key enzymes in β-oxidation cycle of P. entomophila such as 3-hydroxyacyl-CoA dehydrogenase, 3-ketoacyl-CoA thiolase, and acetyl-CoA acetyltransferase were deleted to study the relationship between β-oxidation and PHA synthesis in P. entomophila. Among the mutants constructed, P. entomophila LAC26 accumulated over 90 wt % PHA consisting of 99 mol % 3HDD. A fed-batch fermentation process carried out in a 6 L automatic fermentor produced 7.3 g L(-1) PHA consisting of over 97 mol % 3HDD fraction. Properties of MCL PHA were significantly improved along with increasing 3HDD contents. P(2.1 mol % 3HD-co-97.9 mol % 3HDD) produced by P. entomophila LAC25 had the widest temperature range between T(g) and T(m), which were -49.3 and 82.4 °C, respectively, in all MCL PHA reported so far. The new type of PHA also represented high crystallinity caused by side-chain crystallization compared with short side chain PHA. For the first time, P(3HDD) homopolymers were obtained.
- Published
- 2011
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