Degradation of crude oil and the pure hydrocarbon fractions by indigenous soil microorganisms

Abstract

Petroleum hydrocarbons are a major concern due to their widespread distribution in the environment, and their harmful effects on humans. The use of biodegradation methods to clean soil that has been contaminated by spilt petroleum can be an effective remediation strategy. Therefore, in this study, the presence of indigenous microorganisms in soil contaminated with crude oil was investigated and their ability to degrade petroleum in vitro was studied. Three methods were used to detect crude oil and pure hydrocarbon degradation by bacterial and fungal isolates. Spectrophotometric method, 2,6-Dichlorophenol indophenol (DCPIP) method and hydrocarbon analysis was performed by GC–MS. Furthermore, PCR was carried out to detect the genes AlkB and PMO in the microbial communities. Seventeen bacterial isolates and 5 fungal isolates were recovered from 19 soil culture samples obtained from three different oil-contaminated sites at Taq-taq (TTOPCO) oil field and from a control site without oil contamination. The bacterial samples were identified culturally and morphologically, and the results were validated by genetic analysis. The results of this study revealed that the indigenous bacterial and fungal isolates had a high capacity to degrade crude oil and pure hydrocarbon fractions. Our results provide insight into the great abilities of Bacillus anthracis, Bacillus cereus, Achromobacter sp., Aspergillus lentulus and Rhizopus arrhizus to degrade crude oil and pure hydrocarbon fractions, and these data are supported by the presence of the PMO and AlkB genes in the isolated microorganisms.