Study On The Selection Of Petroleum Degradation Enzyme And The Degradation Characteristics Of Immobilized Enzyme

Petroleum pollution is becoming increasingly searious.Biological remediation of petroleum sites become a new research focus because of its efficiency of remediation and no secondary pollution.The addition of microbial agents to contaminated sites,including exogenous microorganisms and laboratory-enhanced indigenous microorganisms is helpful for remediation.But the microorganisms need some time to adapt to the environment and growth,which may cause a delay of remedation.In order to shorten the time of starting the remedation,simultaneous addition of biological enzymes and microorganisms is carried out.The main contents of this paper are the selection of biological enzymes,the immobilization of biological enzymes and the optimization of synergistic degradation of enzymes.The laccase was selected as the assistant enzyme to promote the degradation of degrading bacteria Dietizas sp.C-1.The optimum conditions were as follows:the glucose was used as the carbon source,the aspartic acid was used as the nitrogen source,the initial culture medium had a pH of 5,the whole culture temperature was 30?,and the revolving speed was 180 rpm.Under the optimized conditions,the laccase activity was the highest after 120h incubation time.The organic resin was selected as the immobilization material and the optimum immobilization conditions were determined.The optimum immobilization conditions were as follows:the additional volumn is 5mL enzyme solution(460U/L)per gram of carrier,the pH value was 6,and the fixed time was 6h.The stability of the laccase was oboviously improved after immobilization.The synergistic degradation efficiency of the enzyme reached to 40%.Analysis of organic matter showed that the content of saturated and aromatic components in oil was decreased by synergistic degradation of enzyme.In summary,the immobilized laccase can promote degradation of petroleum by Dietizas sp.C-1,shorten the starting time of bioremediation and improving the degradation efficiency.It is a feasible way to strengthen the bioremediation of petroleum contaminated sites that dosing degrading bacteria and biological enzymes synchronously.