Biodegradation of selected polycyclic aromatic hydrocarbons by axenic bacterial species belonging to the genera Lysinibacillus and Paenibacillus

Abstract

The quest for competent degraders of recalcitrant polynuclear aromatic hydrocarbons (PAHs) for use in sustainable bioremediation technology has justified the execution of this work. In this study, three bacterial strains (FB-1, FB-2 and FB-3) were isolated from a former industrial site in Bloomington, Indiana. The catabolic versatility of these obtained strains was evaluated on some selected PAH-naphthalene, anthracene, fluoranthene and pyrene. Using the 16S rRNA sequencing analyses, our strains belonged to the family Firmicutes whereby strain FB-1 was identified as Lysinibacillus sp. FB-1, strain FB-2 as Bacterium FB-2 and strain FB-3 as Lysinibacillus fusiformis FB-3. The biodegradation of the selected PAHs was determined using gas chromatography, and the calculated percentage utilization of the selected PAHs varied between 97 and 4%. We further determined the mean biodegradation rates for fluoranthene when supplemented with molasses. The mean biodegradation rates were between (mg L-1 ) 0.214 ± 0.006 and 0.318 ± 0.002, while MSfluoranthene only ranged from (mg L-1) 0.210 ± 0.056 to 0.437 ± 0.176. However, with ANOVA at 5% (P\0.05) there seemed to be no significant difference in the mean