| Bioremediation has been developed into an efficient, low-cost and environmental friendly technology for pollutant elimination. In the bioremediation process, bioaugmentation is often applied. Bioaugmentation is inoculation domestication of highly efficient degrading microorganisms in contaminated sites to increase the rate of biodegradation of pollutants. But the bioremediation of oil-spilled shoreline is a complicated project that is related with the characteristics of contaminated sites, the structure of microbial ecology, as well as various environmental conditions. The structure of oil-degrading consortium and its adaptation to the environment will affect the process of bioremediation.Firstly, highly efficient oil-degrading bacteria are screened and oil-degrading consortium, which has coordinate function, is constructed. Then, the roles of oil-degrading consortium in bioremediation for different oil-spilled shorelines are determined by traditional biology methods and modern molecular biology tools, as well as modern analytical techniques. A lot of works are done to clarify the changes of quantity microorganisms and community structure emphatically and find out the main control factors for bioremediation. With a view to provide a basis for constructing coordinate consortium and enhance the bioremediation efficiency by using bioaugmentation methods. The main results obtained from the paper are as follows:1. On the basis of screening various oil-degrading bacteria with different functional, petroleum hydrocarbon degdading consortium, which have a synergistic role in the metabolic degradation of petroleum hydrocarbons has been constructed.(1) The sediment obtained from the 6th Tianjin Port is used as the source for bacteria screening. With BXPT crude oil, hexadecane and PAHs as sole carbon sources respectively, three consortium, named as BXHH-1, ALK-1, PAH-1, are enriched. In the three consortiums, PCR-DGGE fingerprints show that the dominant bacteria are the most abundant in the consortium with crude oil as carbon source, and its microflora structure is most comprehensive, including consortium in hexadecane and PAHs cultures. This result indicates that oil culture excels hexadecane and PAHs cultures in dominant bacterial populations and consortium structures.(2) By plate separation method, two strains of bacterium, named as TJ-1 and TJ-2, are isolated from enrichment with crude oil as sole carbon source. Strain TJL-1 and TJL-2 are isolated from enrichment with hexadecane as sole carbon source. The last two strains of DHD-1 and DHX-1 are isolated with PAHs as sole carbon source. The six strains of TJ-1, TJ-2, TJL-1, TJL-2, DHD-1 and DHX-1 are identified as Bacillus pumilu, Acinetobacter venetianus, Oceanobacillus Picturae, Bacillus pumilus, Pseudomonas mendocina, Ralstonia pickettii, respectively by their16SrDNA. Among them, TJ-1, TJ-2, TJL-1 and TJL-2 strains are Alkane-degrading bacteria. DHD-1 and DHX-1 strains are PAH-degrading bacteria.(3) Oil-degrading consortium, named as BXHH-2, is constructed, through combining consortium BXHH-1 with strains of DHD-1 and DHX-1. Comparing with BXHH-1 consortium, BXHH-2 consortium has a higher degradation rate not only for alkanes, but also for PAHs, therefore it has a high efficiency in crude oil degradation. This indicates that consortium BXHH-2 has a metabolic role in the degradation of multi-component of crude oil, and it has a good application prospects in field experiment of oil-spilled shorelines bioremediation.2. The roles and using conditions in different oil-spilled shorelines of the highly efficient oil-degrading bacteria agent is initially identified.(1) By comparing the crude oil degradation rate of the different oil-spilled shorelines (Coarse sand-pebble shoreline, fine sand shoreline and slit shoreline), it turns out that the biodegradation system inoculated with oil-degrading bacteria agent and slow-release fertilizer has the highest degradation rate, 49.8%,66.9% and 65.3% respectively, being increased by 28.4%, 28.0% and 29.8% than their respective untreated control system. The biodegradation system inoculated with slow-release fertilizer has the second highest degradation rate, the crude oil degradation rate of A-2,B-2 and C-2 are 43.2%, 56.8%, 64.3% respectively, being increased by 21.8%, 17.9% and 28.8% than their respective untreated control system. Slow-release fertilizer provides more adequate nutrients for indigenous oil-degrading bacteria growth and meanwhile, oil-degrading bacteria agent can acclimatize itself to field conditions, grow fast and change the community structure, effectively enhancing petroleum hydrocarbon degradation rates of the different components. That is the reason that the biodegradation system inoculated with oil-degrading bacteria agent and slow-release fertilizer has the highest degradation rate.(2) For slit shoreline, the degradation rate of the biodegradation system inoculated with oil-degrading bacteria agent and slow-release fertilizer is similar to the biodegradation system inoculated with slow-release fertilizer, 65.3% and 64.3% respectively, being increased by 29.8% and 28.8% than their respective untreated control system. A major limiting factor for degradation rate is short of nitrogen and phosphorus. The increase of petroleum hydrocarbon degradation rates is due to the addition of slow-release fertilizer which can provide the nutrients for the growth of indigenous microorganisms. By comparing the oil-degrading bacteria agent with indigenous microorganisms, it can be found that the microorganisms of oil-degrading bacteria agent can not grow with indigenous microorganisms and cannot change the community structure. The degradation for different components of petroleum hydrocarbon is mainly due to the indigenous microorganisms.(3) In the field experiment of bioremediation of different types of oil polluted shorelines, temperature, dissolved oxygen and pH are suitable for the growth of microorganisms in the field experiment, so they are not the limiting factors for bioremediation in different oil-spelled shorelines.
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