Construction And Degradation Characteristics Of A Crude Oil Microbial System

The pollution of crude oil has been a threat to the ecological environment and human health,and it can not be ignored.Microbial remediation technology is a way to be more economical,efficient and environmentally friendly.However,With the degradation of crude oil microbial single bacteria there is a single degradation of substances,difficult to screen,poor adaptability and other defects.The construction of crude oil degradation Composite microbial system is a kind of strategy to solve the environmental pollution after determining the functional microbial population,This strategy has many characteristics,such as large variety of functions,high economic efficiency and large data volume.Therefore,it is of great significance to screen out the stability of crude oil degradation microbial flora directly for the treatment of crude oil pollution or to further study its internal interaction.The experimental soil is sampled in soil contaminated by crude oil,and microbial flora was screened out.The results are as follows:(1)The use of crude oil as the sole carbon source enrichment and culture of six groups of microbial flora,the detection of a group of crude oil degradation rate of higher and the best functional stability of the composite system And its further study,this compound system named Composite microbial system T-3.(2)The degradation conditions of crude oil were optimized by combining single factor test and response surface method.The optimum conditions of crude oil degradation were as follows: temperature was 38.6℃,p H was 6.63,oil-bacteria liquid proportion was 1∶6.17.Under these condition,the degradation rate of crude oil was 34.21%,which was 1.36 times of that before optimization.(3)Two kinds of non-ionic surfactant of Tween-80 and Triton-100 can promote the degradation of composite microbial system for crude oil.And the larger the effect of Tween-80 on the degradation of crude oil.Under the condition of fermentation,The degradation rate of crude oil was 51.92% when the content of Tween-80 reached 0.30%,and the degradation rate of crude oil was about 51% higher than that under the optimum optimization conditions(4)By detecting the specific activity of two key dioxygenases and the activity of dehydrogenase in the process of crude oil degradation.The trend of three enzymes in the process of gradually weakening the trend is basically the same.(5)Through the plate separation and functional screening of the composite microbial system T-3,the strain with certain degradation function was obtained,and ten strains of bacteria were found to be distributed in Lysinibacillus and Citrobacter by the molecular identification of the 16 S r DNA,of which a large proportion of citric acid bacteria,which belongs to composite microbial system T-3 the kind of dominant bacteria.The degradation rate of crude oil was 51.92% by optimizing the degradation conditions of composite microbial system T-3.The results of preliminary diversity analysis showed that the composite microbial system T-3 was a microbial flora with the advantage of bacteria,with Lysinibacillus and Citrobacter,which was expected to be applied to the bioremediation of crude oil pollution.