Biodegradation of crude oil using marine Bacillus species from Vadinar coast, Gujarat, India

Abstract

The marine environment is open to large sources of toxic organic waste in the form of accidental oil spills. Therefore, it is important to study microbial degradation processes that help reduce the damage caused to the environment. Universally, oil spills produce enormous public anxiety and highlight the need for costeffective, indigenous and environmentally acceptable bioremediation technologies. In recent times, advanced remedial techniques have been opted, such as solidifying, skimming, controlled burning and bioremediation. The present study aimed to isolate crude oil-degrading marine bacteria from Vadinar coastal area of Gujarat, India. Among seven isolates, three potential bacterial strains were chosen for crude oil and petroleum hydrocarbon (PHC) degradation, which were analysed by UV spectrophotometric and fluorometric analysis. These bacterial cultures were verified by 16S rRNA gene sequencing and identified as Bacillus species. Phylogenetic analysis was carried out to confirm the evolutionary relationship with existing oil-degrading species. In the present study, drop collapse, oil spreading and emulsification assay were performed to detect biosurfactant production. Bacillus sp. NM1 KT354277 was capable of degrading 50% of PHCs at the end 72 h for one week under rotary incubation in ONR7a medium. Among the studied strains, Bacillus sp. NM3 KT354278 showed promising lipase activity, viz. 60.72 and 61.19 U ml-1 for 2% of olive oil and tributyrin respectively. Thus, the present study explores indigenous marine isolates that could be utilized as a potential alternative for oilspill remediation in future.