Isolation And Identification Of Oil-degrading Bacteria From The Oil-contaminated Soil And Study On Biodegration Of Oil Contaminants

With the development of industrialization, the problem of oil-contamination to the soil is getting more and more serious. How to clear up or remove the oil-contaminants from the soil becomes an important environmental problem for all countries around the world. Bioremediation, as the methods with fast and safe in processing, low cost and non-secondary contamination, is becoming the main solution to soil environment by oil contamination. The "Autochthonous bioaugmentation" becomes a research hot topics.Microorganisms were isolated firstly in this thesis, and selected efficient oil-degrading strains by shake flask cultivation and soil cultivation; evaluated the three factors that affect the growth and the oil degradation rate of strains to determine the optimum conditions of growth and oil degradation.Results showed as follows:1. Six strains were isolated from four oil-contaminated soil samples, named X3, X5, X8, X9,4 hao②and 5 hao①.2. Under the Inorganic salt medium flask culture conditions, the oil degradation rate of X3, X5, X8, X9,4 hao②and 5 hao①strains reached 57.37%,59.09%,46.94%,31.33%,38.51% and 49.28% in 15 days, much higher than control(21%).Under the soil extract medium flask culture conditions, the oil degradation rate of X3, X5, X8, X9,4 hao②and 5 hao①strains reached 49%,50.08%,39.10%,24.85%,31.12% and 39% in 7 days.Under the soil solid medium culture conditions, the oil degradation rate of X3, X5, X8, X9,4 hao②and 5 hao①strains reached 75%,72%,64.34%,68%,64.67% and 59%. Although the oil degradation rate between the various strains were slightly different, but they were all at a high level, much higher than control.3. X3, X5, X8, X9,4 hao②and 5 hao①strains were identified as Pseudomonas sp., Pseudomonas aeruginosa, Acinetobacter junii, Acinetobacter junii, Microbacterium oxydans and Pseudomonas aeruginosa respectively by physiological and biochemical analysis and sequence analysis of 16SrDNA.4. The growth and oil degrading conditions of the six strains were optimized. The optimal NaCl concentration was 1% for X3,4 hao②and 5 hao①strains, and 3% for X5, X8 and X9 strains. The optimal N source was NH4NO3 for X3, X5 and 5 hao①, and NH4Cl for X8, and (NH4)2SO4 for X9 and 4 hao②. The optimal P source was K2HPO4·3H2O/KH2PO41:1 for all strains.This study provided new microbial resource and information for "Autochthonous bioaugmentation", and it gives great significance on "Autochthonous bioaugmentation".