Research On Degradation Of Lubricating Oil And Remediation Of Contaminated Soil Based On Acinetobacter Pittii

The problem of traditional lubricating oil pollution still exists and continues to increase.In recent years,with the development of the country's industrial layout and the improvement of environmental protection awareness,a large number of enterprises have moved into industrial parks,the land and oil pollution of the old sites has become a new problem.In response to government and business needs,this paper uses Chongqing's typical petroleum hydrocarbon contaminated soil as a sample to isolate a highly efficient lubricant degrading bacteria;the response surface method is used to optimize the degradation conditions of the strain,and the result is to introduce green fluorescent protein particles(GFP)into degradation Strains,using the constructed genetically engineered bacteria to carry out small-scale and pilot-scale bioremediation experiments,and achieved good treatment results.The main research conclusions are as follows:(1)Collect typical lubricating oil-contaminated soil from Chongqing,domesticate it for one month,and then use microbial breeding technology,combined with 24-well plate method,etc.,to isolate a highly efficient lubricating oil-degrading strain R13;through physiology and biochemistry Experiments and 16S r RNA sequence analysis identified the strain as Acinetobacter pittii.(2)Taking A.pittii R13 as the material basis and lubricating oil as the model substrate,the parameters of cell growth and substrate degradation were optimized by single factor experimental research and response surface method.At 33?,p H 7.1,rotation speed 176 rpm,inoculation amount Under 7.2%conditions,A.pittii R13 has good growth and lubricant degradation characteristics;under optimized conditions,the degradation characteristics of A.pittii on different initial lubricant concentrations were studied,and it was found that this strain can achieve 10,000 mg/L The total degradation of lubricating oil show high petroleum hydrocarbon degradation ability.(3)Based on the wild-type A.pittii R13,using transgenic technology,the plasmid carrying the green fluorescent protein(GFP)gene was imported from A.pitti R13 by electro transformation to construct a genetically engineered strain that can realize luminescence monitoring,and Through genetic stability experiments,after 16 days of testing,the cells still have strong fluorescence characteristics,confirming that the strain has good genetic stability;compared with wild-type strains,the characteristics of genetic engineering bacteria for degrading lubricants and degrading ability were investigated Unaffected by the transferred genes,it lays an experimental foundation for the study of lubricating oil contaminated soil remediation.(4)Using genetically engineered strains as exogenous microorganisms,small-scale and pilot-scale bioremediation experiments have been carried out.Through small-scale experiments to determine the effect of surfactant Tween 80,oxygen generator H₂O₂,nutrients and other bioremediation additives on the degradation efficiency of lubricating oil-contaminated soil.Based on this,an outdoor pilot-scale remediation study was carried out.The results showed that the degradation rate of lubricating oil contaminated soil by adding exogenous bacteria can reach 73.32%during the mid-high temperature(25-40°C)remediation period in summer;The second stage of remediation were carried out in the medium and low temperature(10-25?)environment in winter,and finally the lubricating oil contaminated soil with an initial concentration of 12650 mg/kg was reconditioned to an oil content of 495 mg/kg,which was lower than the soil pollution risk control standard(GB36600-2018)The first-class screening value of construction landed stipulated in the standard of 826 mg/kg.At the same time,the soil microbial count results also showed that the genetically engineered bacteria effectively promoted the degradation of lubricating oil during the restoration process,and did not inhibit the normal growth and metabolism of wild bacteria in the contaminated soil,and had no adverse effects on the soil ecological environment.