Optimization of Degradation of Petroleum Crude Oil by Lysinibacillus sp. SS1 in Seawater by Response Surface Methodology

Document Type : Original Article


Department of Biotechnology Engineering, NMAM Institute of Technology, Nitte-574110, Karnataka, India


Introduction: The prevalence of petroleum oil spills in oceans and seas is on the rise in India, resulting in widespread detrimental effects on the environment. Bioremediation by bacteria is an eco-friendly and safe technique for the removal of these pollutants from seawater.
Materials and Methods: An indigenous bacteria, isolated from garage soil was grown on Bushnell Agar plate with Petroleum Crude Oil (PCO) as a carbon source. It was identified by biochemical characterization and 16S rRNA sequencing. The effect of factors such as concentrations of PCO, inoculum and glucose, agitation speed, pH, and degradation time on the growth of bacteria and PCO degradation in seawater was studied by one factor at a time approach. Screening and optimization were performed by Factorial Design and Central Composite Design respectively.
Results: According to findings, isolated bacteria degraded PCO within 48 h and could decolorize 6-dichlorophenol indophenol within 36 h. It was identified as a novel Lysinibacillus sp. SS1, which grew in the pH range of 4.0 to 10.0 and tolerated salinity of 6.0% w/v. Significant factors (concentrations of glucose, inoculum, and pH) were optimized and optimum levels were 11.7% v/v inoculum, 11.36 g/L glucose, and pH 8.6. Maximum degradation of 84 ± 0.13% was achieved when grown in seawater supplemented with 4.0% v/v PCO, at 27 ± 2 °C at 80 RPM in 28 days at optimized conditions.
Conclusions: The present study is the first study reporting optimization of degradation of PCO by Lysinibacillus species. Lysinibacillus sp. SS1 could effectively degrade petroleum hydrocarbons in extreme conditions of seawater and can be applied for the treatment of oil spills.