The Study On Bioremediation Of Oil Pollution By Immobilized Oil-degrading Bacteria

In this paper, immobilized bacteria's degradation of oil was studied. The main contents are: oil-degrading bacteria's isolation, identification and degradation; the immobilization of oil-degrading strains and its degradation; the oil's components changes before and after degradation and the dynamic analysis.Ten oil-degrading strains were isolated from oil-containing soil, they all can make the oil as the sole carbon source. A10 strain's oil degradation is relatively the strongest, comes up to 52.3%, it was identified as Azomonas. When the best inoculation amount is 50mL, oil degradation rate comes up to 51.6%. Degradation time,pH,NaCl concentration temperature,nitrogen and phosphorus all have great influence on A10 strain's oil degradation rate.The oil degradation of immobilized bacteria was studied preliminary, it shows:immobilized bacteria's degradation of oil is better than the free bacteria. When the dosage of activated carbon fiber is 6.25g/L, the best degradation rate is 79.1%; the immobilized time is 36h, the oil degradation rate is 75.6%. pH,degradation time,NaCl concentration,oil concentration,temperature, all have significant impact on the immobilized oil-degrading bacteria. The best degradation conditions are:pH is 7,degradation time is 7d, NaCl concentration is 0%, oil concentration is 9g/L, temperature is 30℃.The study shows that:oil-containing culture medium with different original pH becomes neutral or weak alkaline during the degradation of oil by immobilized bacteria. The immobilized bacteria has good performance in reuse, in repeating 4 times reuse, the oil degradation rate remains at least 69.1%.GC-MS was used to analyze the changes of compositions in oil by degradation:after the degrading of immobilized bacteria, the hydrocarbons decreased. And the components and content of oil have all changed:some of hydrocarbons with the higher boiling point are degraded into low-carbon hydrocarbons with low boiling point. And compared to the free bacteria, after degrading its content of oil are relatively lower. The kinetics of free and immobilized bacteria were studied, they both in line with first-order kinetic model.