Investigating the effect of nutrients and salt concentration on growth and performance of Petroleum-Degrading Bacteria

Crude oil is one of the most important soil pollutant in the south of Iran. Soil pollution takes place at the time of extraction, transferring and refining. Pollution can cause damage to the environment and zoological and plant population of the soil. Using microorganisms can be a suitable way to decrease oil products pollution. In this study effect of 4 strains of bacteria isolated from the soils of Bushehr province with different concentrations of salinity and also nutrients (nitrogen and phosphorous in 0, 48, 72, 144 hours durations in the biodegradation of Phenanthrene and toluene and gas oil was studied. The mentioned strains were named: Pseudomonas Stutzeri, Chryseobacterium, Acinetobacter Johnsonnii, Pseudomonas aeroginosa. The salinity levels were (1%, 3%, 5%) and nitrogen and phosphorous levels were (0.5, 1, 2 mgL-1). The results showed that the best salinity level is 1%. Every four isolated bacteria outstandingly were able to grow and degrade petroleum in 1% salinity in 144 hours after inoculation. Also P. aeroginosa bacteria was more effective in the degradation process of phenanthrene and toluene and gas oil than the other bacteria. The best nitrogen concentration in biodegradation of gas oil was 2 mgL-1 in which the best performance is related to bacteria acinetobacter johnsonii and pseudomonas aeruginosa. The best time in biodegradation of gas oil is 144 hours. The best P concentration in biodegradation of gas oil was 2 mgL-1 in which the best performance is related to bacteria pseudomonas stutzeri.