Effect of Mineral Nitrogen and Phosphate Concentration on Oil Degradation by Two Bacterial Isolates from Persian Gulf Sediments

The effect of nitrogen (N) and phosphate (P) concentrations on crude oil biodegradation by two bacterial strains PG01 and PG02, previously isolated from Persian Gulf, was assessed. In order to determine the optimum concentration of N and P sources for oil consumption bye the isolates, bacteria were cultured in mineral salt medium containing crude oil as sole carbon source and with different concentrations of ammonium chloride (N source) and di-sodium hydrogen phosphate (P source). Culture flasks were incubated at 30 degree centigrade agitating 150 rpm for 5 days. Measuring total protein, as an indicator of petroleum biodegradation, revealed that the optimum N and P concentrations for oil consumption by strain PG01 are equal to 0.146 gram ammonium chloride and 0.024 gram di-sodium hydrogen phosphate per gram crude oil. The other strain, PG02, needed more N source for optimum growth and the results were 0.146 gram ammonium chloride and 0.024 gram di-sodium hydrogen phosphate per gram crude oil.