Biodegradation of Petroleum Oil by a Novel Bacillus cereus Strain DRDU1 from an Automobile Engine

Contamination of soil and air due to hydrocarbon is a global issue and bioremediation provides probably the best way to remediate the contaminants. The current study shows the biodegradation of crude oil, diesel and used engine oil by a newly isolated Bacillus cereus strain DRDU1 from an automobile engine. Hydrocarbon degrading strains were screened on BH (Bushnell and Haas broth) agar supplemented with 2% (v/v) of used engine oil as sole carbon source. The strain was found to be degrading 77, 67%, and 16% of diesel, crude oil, and used engine oil respectively after 28 days under nitrogen and phosphorus stressed condition. It was increased significantly up to 99%, 84% and 29% in presence of nitrate and phosphate supplements. Degradation was confirmed both gravimetrically and by gas liquid chromatographic analysis. The strain proves itself a stress tolerating bacteria by withstanding 7% of salinity, 37% of glucose concentration and 52% of relative humidity. The thermal death point of the strain was found to be 8 oC. The significance of the study is that the percentage degradation of the complex petroleum supplements used in the study was found to be far higher than some of the previously reported values.