Construction and application of an efficient diesel degrading bacterial consortium for oily wastewater bioremediation

The treatment of oil-contaminated wastewater represents a significant environmental challenge. In this study, five highly efficient diesel-degrading bacterial strains were successfully isolated from oily wastewater, which was designated as Pseudomonas sp. ZC1, Vibrio sp. ZL2, Acinetobacter sp. ZY3, Citrobacter sp. GO5, and Enterobacter cloacae GM6. To construct an efficient bacterial consortium based on these five strains, the optimized strain combination of 26 different consortia composed of two, three, four, and five bacterial strains was conducted. The results suggested that a consortium comprising three strains (ZL2, ZY3, and GM6) showed the highest diesel degradation efficiency of 89.66% on day 3, while other strain combinations exhibited lower degradation rates and tended to require more time to achieve comparable efficiency. The orthogonal experiments further determined the optimal inoculation ratios of 1.0%, 0.5%, and 1.5% for strains ZL2, ZY3, and GM6 improved diesel degradation efficiency to 93.65% by day 3. The application of this consortium in the oily wastewater bioremediation confirmed its degrading capacity for n-alkanes (C8-C40) and polycyclic aromatic hydrocarbons (PAHs). This study highlights the excellent performance of the engineered bacterial consortium in the bioremediation of petroleum-contaminated wastewater, demonstrating its potential for scaling up to pilot and full-scale applications.