Optimization of nutrient component for diesel oil degradation by Rhodococcus erythropolis

A novel bacterium T7-2 was isolated from the oil-polluted sea-bed mud of Bohai Sea, northern China, which can degrade diesel oil at 15 °C. This bacterium was identified as a strain of Rhodococcus erythropolis according to its 16S rDNA gene. In order to enhance degradation efficiency, a five-level, three-factor central composite design was employed to optimize the nutrition supplied to artificial seawater. The results indicate that a supplement of 2.53 g (NH4)2SO4 L−1, 2.75 g Na2HPO4 L−1 and 0.01 g yeast extract L−1 to artificial seawater increases the degradation rate from 12.61% to 75% within 7 d.