Screening of Biosurfactant Producing Bacteria Isolated from Hydrocarbon Contaminated Site and Their Potential in Biosorption of Pb(II) and Oil Biodegradation

In the present study, three potentially Pb(II)-resistant and biosurfactant-producing bacterial strains were isolated from a total of 23 strains using various screening methods, investigated for their biosorption of Pb(II) and used for the biodegradation of used motor oil. The results show that strain E1 (Bacillus haynesii) has significantly high efficiency in biodegradation of used motor oil, up to 82 % in the first three days. Maximum Pb(II) biosorption capacities of 238.09 mg/g and 99.01 mg/g were determined for strains E1 and F5 (Pseudomonas aeruginosa), respectively. The biosorption process was found to be in good agreement with the Langmuir isotherm for both E1 (R2 = 0.9614) and F5 (R2 = 0.9646), suggesting monolayer biosorption. The four common screening methods, namely the haemolytic assay, the determination of surface tension, the emulsifying activity and the foam test, were also correlated with the Pearson correlation method.