Biodegradation of Diesel, Crude Oil, Kerosene and Used Engine Oil by a Newly Isolated Bacillus cereus Strain DRDU1 from an Automobile Engine in Liquid Culture

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 diesel, kerosene, crude oil 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. Maximum degradation of hydrocarbon was observed at the addition of 2 % (v/v) of hydrocarbon source in liquid Bushnell and Haas broth (BH) culture medium. The isolate was found to be degrading 67, 57, 72 and 42 % of diesel, crude oil, kerosene and used engine oil, respectively, after 28 days in absence of nitrogen and phosphorus supplements. It was increased significantly up to 71, 64, 83 and 52 % in presence of nitrate and phosphate supplements. It was further increased up to 77, 71, 88 and 61 % upon addition of 0.01 % (v/v) hydrogen peroxide, which acts as an additional oxygen source during oxygen stressed conditions. The strain proves itself to be 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 86 °C. 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.