Degradation of crude oil and pure hydrocarbon fractions by some wild bacterial and fungal species

Abstract

The use of biodegradation as a method for cleaning up soil that has been contaminated by spilt petroleum can be an effective strategy. So, this study investigated the existence of the wild microorganism in soil contaminated with oil and study their ability to degrade petroleum in vitro. Nineteen samples were collected from various locations near Taq Taq (TTOPCO) natural seeps in the Kurdistan Region of Iraq. Morphological, cultural, biochemical tests and molecular identification were used to identify the microbial communities, in addition, spore texture and the colour of the fungal isolates were investigated on the fungal isolates. Out of the19 samples, 17 indigenous bacterial strains and 5 fungal strains were successfully isolated. From the absorption spectrophotometry, Bacillus anthracis, Bacillus cereus, Achromobacter sp. and Pseudomonas aeruginosa for the bacterial isolates grew well on a minimal salt medium supplemented with 1% crude oil. Results showed that these isolates mentioned above had a strong ability to degrade crude oil by reducing the colour of 2,6-dichlorophenol indophenol (DCPIP) from deep blue to colourless. However, for the fractions of hydrocarbon, the bacterial isolates failed and did not affect the colour of any of the fractions. The results for fungi showed that Aspergillus lentulus and Rhizopus arrhizus had a strong ability to degrade both crude oil and fraction F1 by reducing the colour of DCPIP. Each fungal isolates also had a great tolerance to different concentrations of crude oil when grown on solid MSM. This study showed these microorganisms have a strong ability to degrade crude oil and can be used to clean up soil and the environment