Characterization and biotechnological potential of petroleum-degrading bacteria isolated from oil-contaminated soils

A collection of 38 bacteria was obtained by enrichment cultivation from oil-contaminated soils of an oil field in Daqing, China. Twenty-two strains could utilize diesel oil as the sole source of carbon and energy, and 11 strains could degrade the total petroleum hydrocarbons (TPHs) of diesel oil by more than 70% in 7 d. Phylogenetically, 19 of the bacteria related to Bacillus species. About 87.5% TPHs of crude oil were degraded by a consortium of seven strains. Denaturing gradient gel electrophoresis analysis suggested that five of the strains persisted throughout the degradation process. The collection of isolated bacteria might be a useful resource for bioremediation of oil-contaminated soils and biotreatment of oil wastewater.