Pyrene Biodegradation byBacillusspp. Isolated from Coal Tar–Contaminated Soil

ABSTRACT Aerobic, mesophilic bacteria from coal tar–contaminated soil were analyzed for pyrene utilization capacity and identified by 16S ribosomal DNA sequencing as members of three genera: Bacillus spp., Pseudomonas sp., and Rhodococcus sp. The soil contained nine different hazardous polyaromatic hydrocarbons (PAHs): benzo[g, h, i]perylene, dibenzo[a, h]anthracene, indeno[1,2,3-c,d]pyrene, pyrene, acenaphthylene, fluorene, phenanthrene, benzo[k]fluoranthene, and benzo[b]fluoranthene. Bacillus spp. (PK-6) MTCC 1005 showed 56.4% utilization of pyrene (C16H10) (50 μg ml−1) in 4 days, with growth associated biosurfactant activity and resulted in the formation of five new intermediates: phenanthrene (C14H10), 9,10-diphenylphenanthrene (C26H18), 9-methoxyphenanthrene (C15H12O), 5,6,7,8-tetrahydro-1-naphthoic acid (C11H12O2), and 1,6,7-trimethylnaphthalene (C13H14). The results suggested that Bacillus spp. could be found suitable for practical field application for effective in situ PAH bioremediation.