Evaluation of Black Oil Biodegradation by a Consortium of Indigenous Bacillus cereus and Pseudomonas aeruginosa

Black oil is a refined oil product that poses a significant environmental risk. It contains complex multi-hydrocarbons that decompose slowly. Black oil remains in the environment for a long time, which causes various toxic effects. This study was focused on three aspects. First of all, the local bacteria were isolated. Then, the potential of these bacteria for degrading black oil was determined. Finally, the efficiency of the bacterial consortium in degrading black oil was evaluated. Three black oil-degrading bacteria were isolated from crude oil-contaminated soil and molecularly identified by 16s rDNA sequencing as Bacillus cereus strain ZG.S6, Bacillus cereus strain ZG.S12, and Pseudomonas aeruginosa strain ZG.S11. Based on the measurement of optical density and chromatogram analysis, B. cereus strain ZG.S6, B. cereus strain ZG.S12, and P. aeruginosa strain ZG.S11 degrade black oil efficiently by reducing the number of their compounds to 10, 16, and 14, respectively. The results were compared to the complex combination of black oil (control group), which consists of 25 compounds of aliphatic and aromatic substances. The bacterial consortium demonstrated compatibility with each other. This helped them to degrade black oil more efficiently than individual strains, reducing its compounds to seven. Consequently, the consortium is a promising candidate for black oil bioremediation.