Microbial genome of Sphingobium chungbukense DJ77 and production of polyhydroxybutyrate from 4-methoxybenzoate
1Division of Biotechnology, Chonbuk National University, Iksan, Korea, 2Department of Microbiology, Chungbuk National University, Cheongju, Korea
Sphingobium chungbukense DJ77T utilizes aromatic hydrocarbons including biphenyl, anthracene, phenanthrene etc. as a sole carbon source which was isolated from contaminated water sediment of industrial complex in Korea. Based on polyphasic assignment, the strain was originally classified as Sphingomonas chungbukensis and reclassified as Sphingobium chungbukense. In this study, genome sequencing was conducted to gain insight into the biochemical and genetic mechanisms of degradation of PAHs by S. chungbukense DJ77T. The complete genome of the strain DJ77T consists of two chromosomes (3.2 Mb and 1.1 Mb) and six plasmids (382 kb, 310 kb, 270 kb, 229 kb, 36 kb, and 19 kb) with a G + C content of between 59.5 and 63.9%. In addition, S. chungbukense showed poly-β-hydroxybutyrate (PHB) production with 4-methoxybenzoic acid as carbon source at 5 mM concentration. Two important nutrient, nitrogen and phosphorous, concentrations were optimized along with 5 mM 4-methoxybenzoic acid concentration. The thermal and physical properties of the produced PHB were analyzed. These results imply that the DJ77 strain is excellent candidate for conversion of aromatic compounds persistent in wastewaters into biological polyesters. To better understand the mechanism in genetic level, omics analysis using the genome will be required.
keywords:Genome, Sphingobium,poly-β-hydroxybutyrate, 4-methoxybenzoic acid