Bioremediation of petroleum based contaminants with biosurfactant produced by a newly isolated petroleum oil degrading bacterial strain

Abstract

Petroleum based hydrocarbon degrading and biosurfactant producing bacterial strain was isolated from an automobile engine. The strain was identified as Bacillus cereus DRDU1 on the basis of 16S rDNA sequencing analysis. The strain was found to be efficiently degrading 96% of kerosene making it a potential tool for bioremediation of petroleum based contaminants. Production and optimization of the biosurfactant produced by the isolate were also carried out. Surface hydrophobicity trait of isolate was found to be 60.67 ± 1.53% and foaming percentage of the crude biosurfactant was found to be 31.33 ± 0.58%. The presence of amino acids and sugar moieties in the biosurfactant was confirmed by biochemical tests and were further validated by FTIR (the Fourier transform infrared) spectrometric analysis revealing the presence of υOH, υCOO, υCOOH, υCH (stretching), υNH, υCH2, υCH3, and υCH (bending), and υCO (ester) in the surfactant. The decrease in contact angle of hydrocarbon oil from (30.67 ± 1.15)° to (21.3 ± 1.53)° respectively after 3 and 6 days of incubation reveals its potential to emulsify petroleum oil. Further, emulsification index (E24) of biosurfactant against kerosene, crude oil, and used engine oil were determined to be 55.33 ± 1.53%, 29.67 ± 1.53%, and 20 ± 1% respectively which attracts its future application in MEOR (microbial enhanced oil recovery) process.