Enrichment, Isolation and Identification of Polycyclic Aromatic Hydrocarbon Degrading Rhodococcus Ruber Fromsediments

This study focuses on the isolation and biodegradation of PAHs by microorganisms associated with the sediments of automobile workshops of Pondicherry. One of the bacterial isolate selectively enriched in these compounds was identified as Rhodococcus ruber based on morphology, 16S rDNA sequencing and phylogenetic characteristics. Biodegradability tests with selected PAHs supplied as sole carbon sourceshowed that Rhodococcus sp. could utilize PAH compoundsin the order of chrysene>dieseloil>benzanthracene>crudeoil>fluorene>fluoranthene>phenanthrene>dibenzothiophene>naphthalene and anthracene. Absorbance change of mineral medium with phenanthreneat 250ppm, 500ppm and 1000ppm concentration showed a linear increase in growth of the isolate in all the concentrations of phenanthrene. At 250ppm of phenanthrene concentration a lowest average growth of 0.05±0.02 ( ) was observed while the highest optimum growth of 1.02±0.33 ( ) was recorded at 1000ppm concentration of phenanthrene suggesting that R.rubercan endure high concentrations of phenanthrene. Hence,R.ruberstrain has great application indegradation processes involving petrochemical products.