Abstract:
A bacteria consortium, isolated from waste water contaminated with gas and oil, was found capable of degrading a range of PAHs including phenanthrene, acenaphthene, fluorene and fluoranthene. The consortium contains three predominant isolates, one of which was identified as Sphingomonas sp. Via its morphological and biochemical characteristics along with 16S rDNA gene sequencing and consequently designated as Sphingomanas sp. SP2. The organism was able to use acenaphthene as carbon and energy source but unable to use naphthalene, acenaphthylene, dibenzofuran, phenanthrene, anthracene, fluorene, fluoranthene, and pyrene. Cultivation of the organism in minimum medium supplemented with acenaphthene. revealed that the organism could utilize 900 mg/L acenaphthene down to undetectable amount via HPLC within 6 days of which six metabolic products were detected by TLC after 54 h of cultivation. The three major metabolites were further isolated, purified and identified by TLC and HLPC with reference to standard compounds, one of which was likely either acenaphthenequinone or naphthalene 1,8-dicarboxylic acid. It was also found that growth and degradative ability toward acenaphthene of Sphingomanas sp. SP2 was inhibited during cometabolism with 75 mg/L acenaphthene, 200 mg/L naphthalene or 75 mg/L dibenzofuran.