Optimal Production Conditions,Immobilization and Degradation to Simulated Oil Polluted Waste water of Lipase Produced by Paenibacillus polymyxa
Lipase,produced by the endophytic bacterium Paenibacillus polymyxa as experiment object isolated from healthy mulberry leaves was analyzed to explore the application potential in the field of oil wastewater purification.Based on the qualitative analysis of lipase by transparent circle method,factors affecting the enzyme production were studied to optimize the enzyme production conditions.Chitosan-glutaraldehyde was used as a carrier to immobilize the lipase,the degradation ability of the immobilized enzyme to simulated oil wastewater was analyzed.The results showed that the strain had producing characteristics of lipase.The optimal reaction temperature was 39 ℃,and the optimal reaction pH value was 7.0.Sucrose(60 g/L)and rapeseed cake powder(15 g/L)were the most suitable fermenta-tion media for the strain to produce enzyme.When the initial pH value of the medium was at 7.0,and the culture temperature was at 32 ℃,enzyme activity reached to the maximum 2 days after.And the lipase could be effectively immobilized on the chitosan-glutaraldehyde carrier.When degrading the simulated oil wastewater,degradability of free enzyme reached to 638.88 mg/mgprot at 48 h,and then declined.Degradability of immobilized enzyme reached 4 174.44 mg/mgprot at 36 h,and remained at a relatively constant level within 60 h.60 hours after,degradability of immobilized enzyme decreased significantly,however,it still maintained at a higher level compared to free enzyme.Endophytic bacterium P.polymyxa showed high abilities to produce lipase and degrade oil wastewater,which meant the strain had potential application prospects in the field of waste water purification.
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