Isolation and identification of Polycyclic aromatic hydrocarbon degrading bacteria from river and canal sediments in Bangkok metropolis

Abstract

The objective of this study is to isolate the polycyclic aromatic hydrocrbons (PAHs) degrading bacteria from the sediments contaminated with PAHs. PAHs degrading bacteria were enriched from sediment samples in carbon free muneral medium (CFMM) supplemented with fluorene, fluoranthene and pyrene as a sole carbon and energy source. Two bacterial strains could be isolate from the sampling sites at Saen-Saeb Canal and Chao-Phraya River. The strain PY1 could degrade pyrene up to 90.4% at the initial concentration of 100 mg/l within 14 days whereas strain FT1 was able to oxidize fluoranthene for 39% at the same initial condition. In addition, these 2 strains aslo demonstrated their ability in utilizing in acenaphthylene, acenaphthene, dibenzofuran and phenanthrene as sole carbon sources. On the basis of morphological, biochemical characteristics and 16S rDNA wequence analysis, the strain PY1 and FT1 were belonging to the Genus Mycobacterium sp. and Sphingomonas sp., respectively. Along the study, the concentration of 7 PAHs namely acenaphthylene, acenaphthene, dibenzofuran, fluorene, phenanthrene, fluoranthene and pyrene, in sediments samples were determined. Fluoranthene and phenanthrene concentration are in the range of 0.82-6.5 ug/g dry weight and phenanthrene 0.13-0.2 ug/g dry weight, respectively whereas the other PAHs could not be detected.