Degradation Performance of Petroleum-Hydrocarbon-Degrading Bacteria and its Application in Remediation of Oil Contaminated Soil

Abstract

Three petroleum degrading strains were obtained from oily sludge and denoted as A2 (Pseudomonas putida), A4 (Acinetobacter calcoaceticus) and L5 (Sphingomona sp). Crude oil degradation experiments were conducted to investigate the degradation performances of the strains and their bacterial consortium(C) on crude oil. The petroleum degradation rates of A2, A4, L5, and C were 42.8%, 48.01%, 26.56%, and 81.07%, respectively, after 28 days of cultivation, illustrating the removal of petroleum hydrocarbons by the bacterial consortium had a synergistic effect. The bacterial consortium was used to remediate oil contaminated soil in laboratory and the remediation results of the different microbial addition methods-free bacterial consortium (TB), biochar-free bacterial consortium (TB-BC), and biochar-immobilized bacterial consortium (CTB) were compared. The results showed that biochar was beneficial to the colonization of degrading bacteria in the soil, and the number of microorganisms, dehydrogenase activity, and intensity of soil respiration in the CTB treatment were considerably improved compared with those in the other treatments. The removal rates of petroleum hydrocarbons were 18.0% and 32.51% higher than those of the TB-BC treatment and the TB treatment, respectively, indicating that the biochar-immobilized bacterial consortium had a synergistic mechanism of bioaugmentation and biostimulation for the removal of petroleum hydrocarbons.