A hydrocarbon-degrading strain was isolated from a petroleum oil-contaminated site which was identified on the basis of 16S rDNA gene sequencing as a member of the genus Serratia. The isolate reduced surface tension of petroleum oil supplemented medium by 48.35% with respect to control after 7 days of treatment. Fluorescence microscopy revealed that its chemotaxis was towards hydrocarbon. The isolate degraded 87.54 and 85.48% of diesel and kerosene in liquid culture, respectively, after 28 day incubation at 37 ± 2 °C. The ex situ pilot scale bioremediation experiment in which artificially contaminated soil (10 and 20% v/w kerosene) was treated for 7 days showed a germination rate of Vigna radiate seeds of 52% and 72%, respectively. Interestingly, a germination rate of 31% was obtained with the heavily contaminated soil samples collected from the oil spillage site after 20 days of bioremediation treatment. The presence of υCH3 (asymmetric stretching), υC=C (stretch), and υC-C (stretch) in the crude biosurfactant produced by the isolate was revealed by FTIR analysis, and emulsification index (E 24) was found 60 and 56.6%, respectively, against diesel and kerosene oil. The non-cytotoxicity nature of the biosurfactant also supports its potential application in field trial.
Keywords: Biosurfactant; Hydrocarbon degradation; Oil spillage; Pilot scale bioremediation; Serratia sp..