title: [Optimize conditions and activities for neutrophil lipase immobilized by nano-silica dioxide].
abstract: We used adsorption method to immobilize the lipase by using nano-silica dioxide as the carrier. And we also studied different immobilization conditions effects on the catalytic activity. We got optimize immobilization conditions which were as follow the lipase quantity of 28,300 U/g, temperature of 45 degrees C, pH of 7.5 and treated for 10 h. Under these conditions the immobilized lipase activity yield 3867 U/g carrier. The best reactive temperature for immobilized lipase was 45 degrees C and higher than 5 degrees C for free enzyme, and the optimal pH dropped to 5.5 compared that of free enzyme (pH 7.0). The immobilized lipase stability for thermal and pH are improved than free lipase. When temperature was below 70 degrees C the immobilized enzyme activity was over 70% than initial activity. The free lipase activity just kept original 30% at 50 degrees C. When pH was 5-8, the immobilized lipase activity was still more than 50% and the free lipase only remained 20%. When we used the immobilized neutrophil lipase catalyzing different oil to produce biodiesel such as soybean oil, rapeseed oil and waste oil, the esterification rate of rapeseed oil was the highest.
authors.affiliation: Key Laboratory of Applied Enzymology & Engineering, the Engineering Technology Research Center for Municipal Solid Waste and Resource Application of Anhui Province, Hefei University, Hefei 230022, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Jin
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Yang
authors.forename: Ke
authors.initials: K
authors.lastname: Wu
authors.forename: Hualin
authors.initials: H
authors.lastname: Wang
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Yu
mesh_terms: D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008049:Lipase / Q000737:chemistry / Q000378:metabolism*; D053768:Metal Nanoparticles / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013696:Temperature
chemical_list: D004800:Enzymes, Immobilized; D012822:Silicon Dioxide; D008049:Lipase