Bulent Icgen, Gozde Onur and Fadime Yilmaz
Department of Environmental Engineering, Middle East Technical University, Turkey
Degradation of poorly water soluble hydrocarbons, like n-alkanes and polycyclic aromatic hydrocarbons are challenged by some bacteria through emulsification of hydrocarbons by bacterial bio surfactants. In diesel oil bioremediation, diesel oil degrading and surfactant producing bacteria are used to eliminate these pollutants from contaminated waters. Therefore, identifying and characterizing bacteria capable of producing surfactant and degrading diesel oil are pivotal. In this study, bacteria isolated from hydrocarbon contaminated river water were screened for their potential to degrade diesel oil. Primary selection was carried out by using conventional enrichment culture technique, emulsification index measurement, gravimetric and gas chromatographic (GC) analyses of diesel oil degradation. A bacterium with 60% emulsification index and 92% diesel oil degradation ability in 14 days was identified as Acinetobacter haemolyticus Zn01 by 16S rRNA sequencing. A. haemolyticus Zn01 was shown to harbor both catabolic genes alkb and C23O effective in diesel oil degradation. The bio surfactant of the bacterium was also characterized in terms of surface tension, zeta potential, fourier transform infrared spectroscopy and scanning electron microscopy. Being able to degrade diesel oil with a high emulsifying index A. haemolyticus Zn01 seems to have high potential for the elimination of diesel oil from polluted waters.
Keywords: Acinetobacter, petroleum bioremediation, hydrocarbons, E24, alkb, C23O.