Isolation and characterization of a bacterial strain for aniline degradation

Aniline, a serious environmental threat and health risk to living organisms is being released into the soil and water bodies owing to its expanded use in industry. The objective of the present study was to isolate a strain from rhizospheric soil samples of wheat (Triticum aestivum L.) taken from an agricultural site near the industrial area of Faisalabad, with the capability of degrading aniline with its maximum activity. The isolated strain was identified as Staphylococcus aureus ST1 a newly reported strain for aniline degradation. The strain ST1 showed tolerance up to 2000 ppm for aniline on mineral salt media plates and its degradative ability was checked through shake flasks experiments using HPLC. The strain was capable of degrading aniline and utilizing it as a sole source of carbon and energy. Maximum reduction of aniline concentration in medium up to 59.65% was observed after 72 h. An enhancement in biodegradation was observed using glucose as an additional growth substrate. The degradative products analyzed by HPLC were catechol, phenol and some other unknown compounds. Plasmid curing showed the involvement of plasmid encoded genes which was later followed by the isolation of plasmid DNA, which was found to be a large one of ~40 kb having restriction sites for enzymes (EcoRI, BamHI, ClaI, StuI, PstI, and HindIII) used.