Indigenous hydrocarbon degraders further evaluated for their kerosene degradation and biosurfactant production potentials

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2018
Aydın, Dilan Camille
Kerosene, known as jet fuel, is one of the most spilled petroleum product causing serious environmental problems due to recalcitrant compounds found in its structure. The only eco-friendly solution for this problem is bioremediation, in which bacteria are used for the degradation and transformation into non or less toxic forms. The efficiency of this process depends not only on biodegradation ability of the bacterial isolates used but also on their biosurfactant production abilities. Therefore, in this study, 22 previously identified bacterial hydrocarbon degraders were further analyzed for their kerosene degradation and biosurfactant production potentials. Out of 22, 19 bacterial isolates were found to utilize kerosene after pre-selection. The degradation abilities of the pre-selected isolates were determined chromatographically and 7 isolates namely; Pseudomonas plecoglossicida Ag10, Staphylococcus aureus Ba01, Stenetrophomonas rhizophila Ba11, Delftia acidovorans Cd11, Acinetobacter calcoaceticus Fe10, Pseudomonas koreensis Hg11 and Acinetobacter johnsonii Sb01 were stood out as efficient kerosene degraders with degradation abilities in between 69-84%. All the efficient degraders were showed to harbor the alkB gene responsible for kerosene degradation through the polymerase chain reaction (PCR) analyses. Biosurfactant production abilities of 19 kerosene degraders were also tested and Pseudomonas plecoglossicida Ag10, Raoultella planticola Ag11, Staphylococcus aureus Ba01, Enterococcus faecalis Cr07, Acinetobacter johnsonii Sb01 and Pantoea agglomerans Sn11 were determined as biosurfactant producers through oil spreading activity, emulsification index and microbial adhesion to hydrocarbon tests. Blue agar plate method, thin layer chromatography and fourier transform infrared spectroscopy analysis were used to characterize the biosurfactants. The results revealed that, glycolipid type rhamnolipids were majoring in kerosene degraders. The gene responsible for rhamnolipid biosynthesis, rhlAB, was also shown in all the rhamnolipid producers by PCR analysis.