Study on the optimization ecological condition of the microorganism degradation of petroleum contaminants

Taking 3 strains of bacteria (DX-9, DX-4, DX-2) as the tested microorganisms, which were separated from petroleum contaminated soil, the influence of humidity, temperature, concentration of pollutants, the adding amount of hydrogen peroxide and nutrients ratio on the microorganism degradation of petroleum pollutants were studied under shake culture and incubator culture, the tested microorganisms´ optimization ecological condition in polluted environment was investigated. The results indicated that three kinds of microorganism´s ability of degradation petroleum hydrocarbons decreased markedly when the concentration of petroleum contaminants in soil reached up to 150 000 mg/kg, microorganism growth was inhibited markedly. When the concentration of petroleum contaminants was 10 000mg/L, the optimization ecological condition of the three kinds of microorganism degradation petroleum contaminants was as follows: Nutrients ratio (C:N:P) was 60:3:1, the accumulative addition of electron acceptor (H₂O₂) was 12 000 mg/kg, humidity was 50% ~ 60%; the growth temperature for DX-2, DX-9 and DX-4 was 30°C, 30°C and 35°C, respectively.