Isolation, identification and assessment of bioremediation potential of oil-degrading bacteria from oil-polluted sites of south of Iran

The pollution of the environment with oil is spreading throughout the world along with industrial progress. Scientists are looking for many years to find solution for removing contaminants from the soil and water environments. Today, the use of microorganism, for removing crude oil pollution from contaminated sites (bioremediation) is considered by scientists. The present study deals with isolation, identification and characterization of oil-degrading bacteria was isolated from oil-polluted sites of south of Iran (Bushehr province). Initially, a total of 90 isolates were screened from oil-polluted soils in Carbon Free Minimal Medium enriched by gas oil. The 19 isolates were selected based on high level of growth in solid medium. On the basis of morphological, biochemical, 16S rDNA gene sequencing and phylogeny analysis revealed that, the isolates were authentically identified as Stenotrophomonas maltophilia, Ralstonia sp., Vibrio sp., Sphingobacterium sp., Zymomonas sp.,Pseudomonas aeruginosa, Paracoccus sp., Pantoea sp.,Achromobacter xylosoxidans, Acinetobacter johnsonii, Serattia odorifera, Pseudomonas alcaligenes, Entrobacter cloacae, Pseudomonas stutzeri andChryseobacterium sp.. In order to determine the efficiency of these bacteria in hydrocarbon-degrading an inoculum of bacteria containing 108 cfu/ml was used in plate and liquid assays, which were performed in factorial experiment based on completely randomized design with 3 replications. The increasing of diameter of colony and the growth turbidity (OD600nm) as indicators for utilization of hydrocarbon was measured in solid and liquid assays, respectively. Results showed that in CFMM plate assay, highest diameter of colony in presence of toluene and phenanthrene were achieved by Chryseobacterium sp. and Sphingobacterium sp., while in liquid assay and in presence of three compounds Serattia odorifera and Entrobacter cloacae were efficient. Moreover, among three compounds highest degradability in bioremediation was related to gas oil, and it’s followed by phenanthrene and toluene, respectively.

کلیدواژه ها:

Bioremediation ، Oil-degradation bacteria ، Gas oil ، Toluene ، Phenanthrene ، Minimal