fulltext.study @t Gmail

Modification of β-oxidation pathway in Ralstonia eutropha for production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) from soybean oil

Paper ID Volume ID Publish Year Pages File Format Full-Text
20810 43192 2014 7 PDF Available
Title
Modification of β-oxidation pathway in Ralstonia eutropha for production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) from soybean oil
Abstract

Ralstonia eutropha H16 is a useful platform for metabolic engineering aiming at efficient production of polyhydroxyalkanaotes being attracted as practical bioplastics. This study focused on bifunctional (S)-specific 2-enoyl-CoA hydratase/(S)-3-hydroxyacyl-CoA dehydrogenase encoded by fadB to obtain information regarding β-oxidation in this bacterium and to achieve compositional regulation of poly((R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate) [P(3HB-co-3HHx)] synthesized from soybean oil. In addition to two FadB homologs (FadB1 and FadB′) encoded within the previously identified β-oxidation gene clusters on the chromosome 1, a gene of third homolog (FadB2) was found on chromosome 2 of R. eutropha. The fadB homologs were disrupted in R. eutropha strain NSDG expressing a mutant gene of PHA synthase from Aeromonas caviae. The gene disruptions affected neither growth nor PHA production on fructose. On soybean oil, fadB′ deletion led to reduction of PHA quantity attributed to decrease of 3HB unit, while fadB1 deletion slightly increased 3HHx composition without serious negative impact on both cell growth and PHA biosynthesis. Double deletion of fadB1 and fadB′ significantly impaired the cell growth and PHA biosynthesis, indicating the major roles of fadB1 and fadB′ in β-oxidation. When fadB1 was deleted in several engineered strains of R. eutropha possessing additional (R)-enoyl-CoA hydratase gene(s), the net amounts of 3HHx unit in the PHA fractions showed 6-21% increase probably due to slightly enhanced supply of medium-chain-length 2-enoyl-CoAs through the partially impaired β-oxidation. These results demonstrated that modification of β-oxidation by fadB1 deletion was effective for increasing 3HHx composition in the copolyesters produced from soybean oil.

Keywords
Polyhydroxyalkanoate; Bioplastic; Ralstonia eutropha; β-Oxidation; Vegetable oil
First Page Preview
Modification of β-oxidation pathway in Ralstonia eutropha for production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) from soybean oil
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Bioscience and Bioengineering - Volume 117, Issue 2, February 2014, Pages 184–190
Authors
, , , , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering