Screening Of Highly Efficient Oil Degrading Bacteria In Cold Regions And Study And Application Of Their Degradability

Oil is a very important energy that we often use in our daily life and plays a very important role in industrial production in China.However,in the process of oil exploitation,production and transportation,oil is often accompanied by environmental pollution caused by oil leakage.However,the traditional physical and chemical treatment effect is poor,the cost is high,and it is difficult to achieve the purpose of economic benefits.Therefore,it is necessary to select environmentally friendly microbial degradation methods to degrade oil contaminated soil.There are many kinds of microorganisms in nature,which are widely distributed and numerous,easy to reproduce and metabolize quickly.Therefore,diversity is often reflected in the specific repair process.Microbial repair is mainly divided into in-situ repair and ectopic repair.Compared with ectopic repair,in-situ repair has the characteristics of less pollution,environmental friendliness and low cost.The strains screened in situ need to confirm the best environment for their degradation through experiments to improve the degradation effect of the strains.In view of the above problems,this paper screened 7 strains from contaminated petroleum soil as the research object,mainly studying the following contentsThe experimental samples were collected from the soil of an oil-contaminated site in Haicheng City,Liaoning Province.Through the enrichment and purification of the strains,seven strains named HCSY1-7 were obtained.After Gram staining,it was known that the strains were all Gram-positive bacteria.Then the physiological and biochemical characteristics of the strains were studied.The molecular study of the strains concluded that the 1#,5#and 7#strains belonged to Bacillus,and the 4#strains belonged to Bacillus,Moreover,the degradation effect of different strains has great differences,especially the degradation performance of 4#and 5#strains is good,and the degradation effect can reach more than 70%.Finally,the 4#strains with good degradation effect and easy to survive are sent to Beijing China Microbial and Bacterial Collection and Management Center for the collection number CGMCC.NO26265.According to the GCMS experiment,the main form of carbon chain in the degradation substrate of seven strains is C₃₂H₆₆（n-triacontane）.In the optimization of the degradation conditions of the strains,it is known that the PH,temperature,degradation time,salinity,carbon source and nitrogen source of the strains have a great impact on the degradation effect of the strains;The optimum temperature of the strain is 32-33℃,the optimum PH is neutral,and the degradation performance of the strain is the best after about 7 days of degradation.The degradation effect of the strain4#and 5#is the best when the nitrogen source is NH₄Cl,while the degradation effect of the phosphorus source is the best when KH₂PO₄+K₂HPO₄is the double phosphorus source.The degradation effect of the strains has changed significantly after the strains were mixed according to different proportions,especially the degradation effect of the strains 4#and 5#with better degradation effect reached92.4%after the strains were mixed according to the ratio of 3:2,which has improved compared with the single strains 4#and 5#,and has certain value for the application in real life.