Biodegradation of crude oil using bacterial strains isolated from the oil contaminated soil of Shakar Dara oil fields of Pakistan

Abstract

Oil spillage is an important environmental concern especially in areas near to the oil fields. Microorganisms present one of the most suitable and sustainable way of oil degradation and soil remediation for reuse. The present study was based on the identification of the oil degrading bacteria isolated from the oil contaminated soils located near the Shakar Dara oil fields of Kohat District, Pakistan. The rate of oil degradation by the selected bacterial isolates and the required optimum pH and temperature conditions were also assessed in the present study. Out of the total 15 bacterial isolates, 12 had noticeable oil degrading abilities. In the hydrocarbons sensitivity assays using 5% crude oil, 04 isolates denoted as M1, M2A, M3 and M7 displayed the maximum growth and were chosen for further optimization. The maximum growth was observed at pH 7 and at a mesophilic temperature range (37 °C–40 °C). The selected isolates M1, and M3 were identified as Stenotrophomonas, and Bacillus while, the isolates M2A and M7 were identified as Salmonella spp. respectively. The oil degrading efficiency of Stenotrophomonas sp. M1 was 43% followed by that of Bacillus sp. M3 as 34%. It was concluded that the selected indigenous bacterial strains specifically M1 and M3 aid in the removal of organic contaminants probably owing to some specific enzyme systems synthesized by bacteria. The novel strains being capable of degrading crude oils will help in understanding the activated enzyme machinery and further in the development of an indigenous technology for bioremediation of such contaminated areas.