Construction Of Oil Degradation Bacterial Consortium From Coastal Waters And Its Technique Of Immobilization

With the continuous exploitation of the seabed and coastal oil, the environmental pollution, especially the marine oil pollution caused by oil spilling due to transportation and drilling is more and more prominent, it has brought great distress to the marine environment and human’ssurvival and development, also caused a great waste of resources.It is imperative to deal with this problem. Compared with the physical and chemical methods, biological treatment technologyfor the safe, efficient, economic and no secondary pollution, without large equipment, attracts more and more attention. Therefore, studies on the biodegradetion of petroleum polluted soil by microorganisms are hotspots today.The main content of this study was to find a immobilized bacteria that friendly and suitable for marine environment oil degrading, including diesel and oil-degrading bacteria; optimizing condition of degradation; screening immobilization carrier; to analyze the changes of the compositions in crude oil degraded by immobilized bacteria and to simply simulate crude oil degradation by immobilized bacteria in the offshore waters. The main conclusions are as follows:(1) Diesel oil or crude oil as the sole carbon source, more than 50 high effectively degradation strains were screened from Shekou and Yantian harbor area.Five high effectively degradation strains for diesel oil or crude oil were chosen and only the the most efficientcombination werechosen by mixing experiments. The inoculums dosage was confirmed by orthogonal experiment. Finally, CQ1 bacterial consortium for diesel oil and SQ1 bacterial consortium for crude oil were constructed.CQ1 was composed of strainsC1-8, C2-10 and C3-13, SQ1 was comprised ofSl-38,S1-30and S2-13.the effect of environmental factors on diesel oil and crude oil biodegradation by bacterial consortium was studied through single factor experiment.Results indicate thatthe best degrading rate would be reached60.5% when CQ1 strains were inoculated 30℃, pH 7.6, shaking speed 200 r/min and diesel concentration 20 g/L.CQ1 degradation of diesel oil was increased with the increasing incubation time and increased with giant gradient within 3 to 9 days.The degradation rate were up to 60% in 9 days.After that degradation of diesel oil was increased with small gradient.The best degrading rate would be reached69.25% when CQ1 strains were inoculated 30℃, pH 7.6, shaking speed 200 r/min and diesel concentration 20 g/L.SQ1 degradation of diesel oil was increased with the increasing incubation time.(2) Using physiological and biochemical experiment and 16SrRNA 基因 sequencing, diesel as the sole carbon source, strains mainly found Microbacterium, Pseudomonas, Corynebacterium, Ochrobactrum and Ensifer. Crude oil as the sole carbon source, strains mainly foundParacoccus, Labrenzia, Sphingopyxis, Pseudomonas and Dietzia. C1-8 belonged to Microbacterium sp, C2-10 belonged to Ensifer sp, C3-13 belonged to corynebacterium variabile. S1-30 belonged to Corynebacterium sp, S1-38 belonged to Dietzia sp, S2-13 belonged to Labrenzia sp.(3) The characteristics of degradation by immobilized SQl, the best carrier, the optimum dosage of carrier and the optimum immobilization time was studied simply.Results indicate thatthe best degrading rateof straws and nonwovenswould be reached 76.85% and 73.08%respectively, all have above the rate of SQ1 bacterium solutionThe optimum dosage and the optimum immobilization time of SQl by nonwoven were 25.0 g/L and 36h. The optimum dosage and the optimum immobilization time of SQ1 by straws were 25.0 g/L and 36h. In the reaction system, for both immobilized SQ1 carrier, the degradation of crude oil was increased with the increasing incubation time. The best degrading rate would be reached73.08% and 76.85% respectivelyafter 9 days incubation(4) Research the removal efficiency for immobilized SQl in real seawater and the suitable nutritional conditions, by applying different inorganic nitrogen source including carbamide, KNO3, (NH4)2SO4, NH4Cl and phosphorus sourceincluding K2HPO3 and KH2PO3 Results indicate that the best nitrogen source was NH4Cl, phosphorus source was KH2PO3 The best degrading rate would be reached66.05% when the dosage of NH4Cl was 5.08g/L,the dosage of NIH4Cl was1.14g/L,compared with theblank control.(5) Using GC-FID and GC-MS analyzed the degradation condition of diesel for CQ1 and SQl. Results indicate thatmost n-alkanes C11-27 can be degradated by bacteria consortium and the diesel degradation rate of alkanes C21-27 were up to 100%.for CQ1 the degradation condition of dieselwas better than each single strain.This research set up the foundation for the ocean oil remove by microbiological method and provide a desirable strain resource. Immobilization bacteria consortium shows a great applicable prosperity in bioremediation of oil spill at sea.