Research On Functional Microbiome Construction And Degradation Kinetics Of Gasoline And Diesel Pollution

Due to the exploitation of petroleum and the rapid development of petroleum industry,petroleum resources,while providing economic benefits to human beings,also pose a threat to the natural environment(atmosphere,soil,surface and groundwater)in the ecosystem.The treatment and remediation of soil contaminated by gasoline and diesel oil,which are related to petroleum processing products,has attracted the attention of researchers particularly.As a new clean technology,bioremediation has the characteristics of low cost,easy operation and no secondary pollution,however,the technique is limited to the screening of high-efficient degrading strains,so it has not been widely and rapidly applied on a large scale presently.This study aimed at the limitation of soil bioremediation technology contaminated by gasoline and diesel and the main components of gasoline and diesel,n-Dodecane,iso-Octane,Cyclohexane,Methylcyclohexane,Toluene and so on five model compounds were selected as the sole carbon sources,combining with enzyme activity evaluation and traditional screening techniques,the strains of high efficient gasoline and diesel oil degradation were screened and the strains were compounded.The optimization of screening efficiency,compounding mode and microbial community function can provide theoretical and methodological basis for enhancing microbial remediation technology.Its main research contents include the following aspects:1.The soil contaminated by gasoline and diesel in Jinan Refinery,the contaminated area of tanker trucks transporting gasoline and diesel,and the soil contaminated by gasoline and diesel around a gas station in Jinan were studied.According to the Alpha species diversity,community Heatmap diagram analysis,variance analysis,Jinan refinery and gas station pollution diversity in soil samples was significantly higher than that of the tanker oil sludge samples.At the Phylum level,Actinobacteriota was the dominant species in the contaminated soil of oil refineries and gas stations,and Proteobacteria was the dominant species in the sludge of oil tanker trucks.At the Order level,the dominant species Corynebacteriales and Pseudomonadales in the oil sludge of oil tanker were significant,while the dominant species in the contaminated soil of gas station and oil refinery were not obvious,and all were Vicinamibacterales.2.The five model compounds of n-Dodecane,iso-Octane,Cyclohexane,Methylcyclohexane,Toluene were selected as the only carbon source,after screening,culturing,separating and purifying,nine degrading strains were obtained from contaminated soil by the method of enzyme activity determination:KJ-1 and KJ-2,were identified as n-Dodecane-degrading strains,which were identified as Acinetobacter sp.and Bacillus sp.with 3765mg·L^-1 n-dodecane degradation rates of 91.99%and 89.51%respectively.The optimal growth conditions of KJ-1 were temperature 30?,initial pH of inorganic salt medium 7.5,inoculation amount 10%,initial concentration of n-dodecane 3765mg·L^-1 and culture time 6 days.3.Two iso-Octane-degrading strains YXW-3 and YXW-4 were screened and identified as Pseudomonas aeruginosa sp.with the 500mg·L^-1 iso-Octane degradation rates of 86.69%and 85.53%respectively.One Cyclohexane-degrading strain HJW-1 was screened and identified as Bacillus sp.with the 500mg·L^-1 Cyclohexane degradation rate of 78.54%.Three Methyl cyclohexane-degrading strains JH-1,JH-4 and JH-5 were screened and JH-1,JH-4 identified as Pseudomonas sp.,and JH-5 identified as Enterococcus sp.,with the 500mg·L^-1 Methyl cyclohexane degradation rates of 63.25%,75.53%and 76.53%respectively.A toluene-degrading strain JB-1 was screened and identified as Bacillus sp.with the 433mg·L"1 toluene degradation rates of 84.69%.4.Different nine combinations of strains were selected,the degradation rate of gasoline and diesel oil was obtained quickly by using the method of enzyme activity determination,then the functional microbial flora of gasoline and diesel were constructed.By optimizing the combination form of bacterial strain,the microbial strains of gasoline and diesel oil were 92-2 and CY-1,respectively.The degradation rates of 748.70g·L^-1 gasoline and 827.90g·L^-1 diesel oil were 98.34%and 96.43%,respectively.5.Haldane equation was used to analyze the experimental data,and the growth kinetics model of functional bacteria 92-2 and CY-1 were obtained for gasoline and diesel oil respectively.By date fitting analysis of gasoline and diesel,kinetic model of degradation of 92-2 and CY-1 were established respectively.Growth Kinetics model of gasoline functional strain:?_x=0.32C_s/[5.7+C_s+C_s²/198]Growth Kinetics model of diesel functional strain:?_x=0.28C_s/[7.28+C_s+C_s²/261]Kinetic model of gasoline degradation by functional bacteria:?_s=0.39?_x+0.108 Kinetic model of diesel degradation by functional bacteria:?_s=0.38?_x+0.227...