Isolation And Characteristics Of A Petroleum-degrading Strain

With the widespread use of oil,oil pollution has become a serious environmental problem.So far,there have been a lot of leakage of huge oil spills,causing serious harm to the environment.The methods commonly used to contral oil pollution were physical methods,chemical methods and biological methods.Among them,biorestoration has a wide application foreground because of its low cost,good effect and no secondary pollution.The screening and degradation characteristics of highly efficient petroleum-degrading strains were the prerequisites for the application and development of bioremediation technology.In this paper,a highly efficient oil degrading strain was identified and studied which was isolated and screened from the polluted sandy soil near Dalian Port,and it provided a theoretical basis and application basis for the biological treatment of petroleum pollution.The results were as follows(1)A strain of highly efficient petroleum hydrocarbon degrading bacteria was isolated from the polluted sandy soil near Dalian Port,and the strain was named NDL-5.(2)Morphological observation,physiological and biochemical experiments and 16S rDNA sequence analysis of the strain NDL-5 were identified as Bacillus.(3)The qualitative and quantitative analysis of the standard oil before and after degradation of the strain NDL-5 was carried out by GC-MS.The results showed that the degradation rate of strain NDL-5 was more than 80%,which could completely degrade n-tridecane,bromododecane,2,6,10-trimethyldodecane and naphthalenes.(4)When the concentration of naphthalene was 1 g/L,the degradation rate of naphthalene was 90.2%by UV spectrophotometry after 6 days culture.(5)The results showed that the total degradation rate of the strain NDL-5 to the standard oil component increased from 63.7%to 87.7%after adding N and P nutrition.The degradation rate of oil and the process of environmental restoration.were inproved when N,P nutrition be added.Secondly,the effects of different amount of bacteria on bioremediation were studied.The results showed that when the inoculation amount of bacteria was 20%,the total degradation rate of the strain NDL-5 was 83.5%,and the degradation effect was the best.