Heavy oil biodegradation by mixed bacterial consortium of biosurfactant-producing and heavy oil-degrading bacteria

Abstract

Environmental contamination from heavy oil is a worldwide problem. In this study, a heavy oil degrading bacterial consortium DL-1314 composed of Bacillus sp. DL-13, Brevibacillus sp. DL-1 and Acinetobacter sp. DL-34 was constructed. The constituents were all biosurfactant-producing bacteria and heavy oil-degrading bacteria. Bench-scale experiments were used to investigate the performance of the bacterial consortium in degrading heavy oil. The bacterial consortium could quickly start up the heavy oil biodegradation and degrade 60.75% of heavy oil in 8 days. Gas chromatography-mass spectrometry (GC-MS) analysis evidenced that the bacterial consortium could degrade 66.32% of saturated hydrocarbons and 63.16% of aromatic hydrocarbons, especially C15-C35 n-alkanes and 2-ring-5-ring PAHs. Analysis of the dynamic changes in the consortium DL-1314 revealed that Bacillus sp. DL-13 played a major role in the formation of surfactants in the early stage of biodegradation, Brevibacillus sp. DL-1 degraded light hydrocarbons in heavy oil, and Bacillus sp. DL-13 and Acinetobacter sp. DL-34 degraded bio-refractory hydrocarbons in heavy oil by synergistic metabolism. In-depth characterization composition of the heavy oil and the microbial consortium revealed chemical and degradation diversity, providing a more comprehensive and accurate understanding of the biodegradation process.