Microbial Diversity Of Petroleum Contaminated Soil In Northern Shaanxi And The Characteristics Of Isolated Petroleum Degrading Bacteria

Located in the central area of the Loess Plateau,Northern Shaanxi is one of the four major energy bases in China,being rich in petroleum resources.At the same time,a large amount of oil pollution will be produced in Northern Shaanxi every year,which seriously affects people's daily life.Microbial remediation has been highly valued by environmental remediation workers because of its small disturbance to the environment and obvious remediation effect.Under natural environment conditions,the petroleum degrading microorganisms can occupy only 0.1% of the total microbes.High oil concentration in the environment can enrich and domesticate of the petroleum degrading microorganisms,which makes the proportion of oil degradating microorganisms rose to 1%-10%.Isolation of oil degrading bacteria from the environment polluted by oil is currently one of the important ways to get oil degrading micrbial resources,and also is a central part of the microbial remediation of oil pollution.The main contents of this study are as follows :(1)The contents of nitrate nitrogen,ammonium nitrogen,rapidly available phosphorus(AP),rapidly available potassium(AK),organic matter(SOM)and p H of oil-contaminated and non-oil-contaminated soil from Baota,Wuqi,Jingbian and Yanchang counties in northern Shaanxi Province were measured.High-throughput sequencing technology was used to anylize the microbial community structure in oil-contaminated and non-oil-contaminated,and the effects of petroleum on soil physical and chemical properties and microbial community structure were studied by redundancy analysis.(2)Efficient oil-degrading bacteria were isolated from oil-contaminated soil and their degradation characteristics were studied.The main findings of the study are as follows:(1)By measuring the physicochemical properties of the oil-contaminated and nonoil-contaminated soil in four counties in northern Shaanxi,it was found that the contents of organic matter(SOM),and p H in the oil-contaminated soil were increased,while the contents of nitrate nitrogen and ammonium nitrogen,available phosphorus(AP)and available potassium(AK)were decreased compared with those in the non-oilcontaminated soil.(2)Using high-throughput sequencing to anylize of oil-contaminated and non-oilcontaminated soil microbial community diversity,oil pollution soil microbial abundance and diversity in the oil-contaminated soil were decreased.The abundance of Mycobacterium?Kaistobacter?Pseudonocardiaa were dropped while the abundance of Arthrobacter was increased.(3)Two strains of highly efficient oil-degrading bacteria were isolated from oilcontaminated soil and the two strains were identified by molecular biology as Dietzia sp.OS33 and Rhodococcus sp.OS62-1.The optimal growth p H of the two strains was 8.0,the p H tolerance range was 4.0?11.0,the salt tolerance of OS33 was 8% and OS62-1 was5%.The optimal nitrogen source was ammonium sulfate and sodium nitrate mixed nitrogen source.The surface hydrophobicity of OS33 and OS62-1 was 68.1% and 45.3% respectively.