Study On The Bioremediation Of Marine Oil Spill Based On Microbial Oil-degrading Consortium

42 strains of bacteria which could utilize petroleum hydrocarbons as the sole carbon and energy sources were obtained from marine sediments. Various taxonomic methods were used to identify the potential oil-degrading novel species, and the results showed that strain PY97S was a new species of genus Marinobacter. Characterization of the degradative ability of strain PY97S indicated that it could degrade 11 kinds of PAHs. Gas Chromatography-Mass Spectrometer ( GC-MS) analysis showed that its degradation rate of typical PAHs phenanthrene was 99% after 10 d'incubation when the initial concentration of the substrate was 0.2 g/L.According to the principle of function complementation, we constructed three triple-component consortium. The results of GC-MS and weighting method showed that the oil degradation rate of consortium DC10 was remarkable in trophic environment, up to 82.47% in 15d when the initial concentration of the substrate was 0.1 g/L, which was higher than that of the bacterial pure culture. Further, we detected its degradation rate of oil by weighting method at different initial concentrations of nitrogen and phosphorus and various N:P ratio in 15d in sea substrate. The degradation rate of oil with 100 mg/L N and 10 mg/L P was the highest, reaching 53.46%, and 26.72% higher than the treatment without addition of nitrogen and phosphorus.The oil bioremediation agent was developed with the fermentation culture of the three bacterial strain of consortium DC10 mixed at the cell number ratio of 1:1:1. In order to test the degradative effect of the agent, indoor and outdoor simulation oil spill bioremediation experiments were carried out. In the former, we setted up 6 different treatments, and used GC-MS and other methods to evaluate the degradative effect of the agent. The results showed that the degradation rate by the"consortium + nutrient"treatment was 58.09% for the total alkanes and 48.92% for the total alkylated polycyclic aromatic hydrocarbons in 21d's incubation, which was 44.09% and 29.57% higher than the negative control treatment, respectively. Besides, the degradation rate by the"consortium + nutrient + surfactant"treatment was 58.07% for the total alkanes and 43.22% for the total alkylated polycyclic aromatic hydrocarbons in 21d's incubation, respectively. In the latter, we used GC-MS and UV spectrophotometry to assess the degradative effect of the agent. The degradation rates by the"consortium +slow-release fertilizer"treatment based on calculation of degradation indices n-C17/Pr and n-C18/Ph amounted to 78.28% and 75.65% respectively. And the degradation rates of the"consortium + nutrient"treatment were 43.47% and 45.07%, The degradation rates of the negative control were 18.77% and 18.67% respectively, which indicated that the stimulation effect of slow-release fertilizer was better than that of the dissolved nutrient treatment. In general, the above results showed that the oil bioremediation agent based on defined consortium developed in this study was a potential candidate which would be applied in the emergency response of real oil spills.