氧化硅介孔泡沫材料固定木瓜蛋白酶的研究

以氧化硅介孔泡沫材料(Siliceous Mesocellular Foam, MCF)为载体对木瓜蛋白酶进行了固定, 并对固定化酶的性能和影响因素以及酶的稳定性作了系统的研究. 结果表明, 木瓜蛋白酶在MCF上能获得较大的负载量（334mg/g MCF）. 固定化木瓜蛋白酶的最适反应温度较游离酶提高了10℃, 最适pH向碱性方向偏移0.5个单位. 固定化木瓜蛋白酶的米氏常数（Km）为6.99×10^-3mol/L, 在八批次操作后酶活保留65.1%. 在4℃条件下放置60d后, 固定化酶的剩余活性仍保持75%以上, 而游离酶的活性只有初始活性的53.6%. 与游离酶相比, 固定化木瓜蛋白酶的pH稳定性、热稳定性、操作稳定性和储藏稳定性都有明显改善, 有利于酶的重复使用和储藏. 介孔泡沫材料是一种良好的木瓜蛋白酶固定载体.

Immobilization of Papain on Siliceous Mesocellular Foam

Siliceous mesocellular foam (MCF) was employed as carriers in the immobilization of papain, and the properties and the stabilities of the immobilized enzyme were investigated in detail. The results show that the amount of papain immobilized on MCF material reaches 334 mg/g MCF. The optimal pH and reaction temperature of the immobilized papain are 7.5 and 50℃, respectively. The Michaelis constant (Km) of immobilized papain is disclosed as 6.99×10^-3mol/L by the Lineweaver-Burk plot at 37℃. The immobilized papain with 65.1% of the activity remaines after repeating the catalysis of casein for 8 times. After stored at 4℃ for 60d, the immobilized papain retaines 75% of the activity, while the free papain only retains 53.6%.The pH, thermal, operational, storage stabilities of the immobilized enzyme are improved due to the large pore microenvironment and the shield of the mesopores of MCF, which can be considered as excellent supports for papain immobilization.