| In the process of oil exploitation,transportation,storage and processing,leakage and other safety accidents often occur in the process,which will lead to a large amount of oil into the soil environment,causing a large area of pollution to the soil environment.Microbial remediation is a commonly used technology for remediation of organic contaminated soil,so screening out high-efficiency petroleum hydrocarbon degrading bacteria is the key to the successful implementation of microbial remediation technology,which has important practical application value for soil remediation.In this paper,the oil contaminated soil in Northern Shaanxi Province is taken as the main research object,and crude oil is the only carbon source.On the basis of the traditional enrichment culture and lineation separation screening method,sponge and Teflon membrane are used as the adsorption medium to screen the oil hydrocarbon degradation bacteria with adsorption.Physiological and biochemical analysis and 16Sr RNA identification were carried out for the selected strains,and their growth,degradation characteristics and degradation genes were studied.The remediation of oil contaminated soil was studied through laboratory simulation,and the degradation characteristics of the selected degradation bacteria for petroleum hydrocarbons were studied.(1)With L9 as the screening medium and petroleum hydrocarbon as the sole carbon source,four strains of petroleum hydrocarbon degrading bacteria were isolated from the oil polluted soil in Northern Shaanxi Province by using the classical enrichment culture method(Y),adding adsorption medium sponge(H)and Teflon membrane(T)to L9medium.After 16S rRNA sequencing,four strains of petroleum hydrocarbon degrading bacteria were identified as Acinetobacter,hemolytic Acinetobacter,calcium acetate Acinetobacter and Acinetobacter.(2)Among the four strains,alkane primers and PAH primers were all expressed in four strains,and the best gene expression was found in one strain selected by classical enrichment culture and Teflon membrane as adsorption medium.When the DNA of the strain was diluted to 55,the two genes(?subunit dioxygenase gene controlled by one primer and alkane monooxygenase gene controlled by five primers)could still be detected).When the strain contains?-subunit dioxygenase gene alkane monooxygenase gene,the degradation of petroleum hydrocarbons is relatively good.(3)The degradation of petroleum hydrocarbons in the liquid phase of 500,1000 and2000mg/L was studied by using the degradation bacteria selected from different systems.The results showed that the strains screened from different systems had good degradation ability to the liquid petroleum hydrocarbons with the concentration of 500-2000mg/L.When the concentration of petroleum hydrocarbon is 500mg/L and the strain is in different systems,the degradation rate of petroleum hydrocarbon can reach over 85.6%.When the concentration of petroleum hydrocarbon is 1000mg/L,the degradation rate of petroleum hydrocarbon in different systems can reach over 92.8%.When the concentration of petroleum hydrocarbon is 2000mg/L,the degradation rate of petroleum hydrocarbon in different systems can reach over 93.5%.(4)According to the inoculation amount of 10~5 CFU/g soil and 10~8CFU/g soil,the selected petroleum degrading bacteria were inoculated into the oily soil(the initial concentration of petroleum hydrocarbon is 16080 mg/kg)for 120 days for remediation.Through the determination of petroleum hydrocarbon content,soil p H and microbial activity in the remediation process,it can be found that the inoculation amount is 105 The degradation rates of petroleum hydrocarbons were 15.2%,13.9%and 11.7%respectively when inoculated with three types of degradation bacteria,i.e.Y,T and H.When inoculated with 10~8 CFU/g soil,the degradation rates of petroleum hydrocarbons were 21.6%,19.3%and 18.8%respectively.The effect of 10~8 CFU/g is better than that of 10~5Cfu/g.The degradation ability of different strains to petroleum hydrocarbon in soil is Y>T>H.(5)The activities of soil microorganisms to metabolize petroleum hydrocarbons,alkanes and polycyclic aromatic hydrocarbons(PAHs)in the remediation of oil contaminated soil by Y,H and T degradation bacteria were measured.The relationship between soil microorganism and hydrocarbon metabolizing activity is:crude oil metabolizing activity>alkane metabolizing activity>polycyclic aromatic hydrocarbon metabolizing activity.(6)When the petroleum hydrocarbon is used as the substrate for metabolism,the soil microbial activity of inoculated degradation bacteria Y is higher than that of inoculated degradation bacteria T is higher than that of inoculated degradation bacteria H;when the polycyclic aromatic hydrocarbon is used as the substrate for metabolism,the soil microbial activity of inoculated degradation bacteria h is higher than that of inoculated degradation bacteria t is higher than that of inoculated degradation bacteria Y;the soil microbial activity of inoculated degradation bacteria y is higher than that of inoculated degradation bacteria T;the n-hexadecane is higher than that of inoculated degradation bacteria Y When the substrate was metabolized,the activity of soil microorganism inoculated with degradation bacterium T was higher than that inoculated with degradation bacterium Y and higher than that inoculated with degradation bacterium H;... |
PDF Full Text Request