Bioaugumentation of Crude Oil Contaminated Soil Using Bacterial Consortium

Abstract

Crude oil utilizing bacteria were isolated from crude oil polluted soil collected in Ekpan-Warri, Delta State, Nigeria. They were identified as species of Pseudomonas, Bacillus, Streptococcus and Micrococcus. These organisms utilized Agurra (Nigeria) Light crude oil as a source of carbon and energy at varying rates and formed unstable and less stable emulsion in the oil medium. Based on their high ability of utilization of the crude oil, three bacterial strains Bacillus megaterium, Pseudomonas putida and Pseudomonas aeruginosa were put together into a mixed bacterial culture (MBC) to decontaminate soil intentionally polluted with 30% (v/w) crude oil. The results revealed that the bioaugmentation caused changes in the pH of the soil and in the CO2 evolution. The pH of the amended oil polluted soil ranged from 6.15 to 7.66 while that of the unamended oil polluted soil ranged from 6.57 to 7.12. 68.2 mg CO2 was liberated in amended soil as compared to 26.4 mg CO2 liberated in unamended soil after 16 days. GC-MS analysis of the residual oil revealed that the oil components were more extensively degraded in the soil amended with the mixed bacterial culture than the unamended soil. The resistant phytane and pristane were equally attacked in the soil. The results suggest that a consortium of Bacillus megaterium, Pseudomonas putida and Pseudomonas aeruginosa can be useful in reclaiming crude oil polluted soil in the tropics