改性菠萝皮渣纤维素固定化菠萝蛋白酶研究

为了探究改性纤维素作为固定化酶载体的可行性,在离子液体中用L-丝氨酸对提取的菠萝皮渣纤维素进行均相改性,并将改性菠萝皮渣纤维素用于固定化菠萝蛋白酶。采用傅里叶变换红外光谱仪、热重分析仪以及X射线衍射光谱仪对菠萝皮渣纤维素、改性菠萝皮渣纤维素以及固定化酶进行了表征。结果表明,菠萝皮渣纤维素被成功改性,晶体结构从纤维素Ⅰ型转变为纤维素Ⅱ型;菠萝蛋白酶成功地固定在改性菠萝皮渣纤维素上,且固定化酶较改性菠萝皮渣纤维素的热稳定性得到提升。对酶的固定化工艺和酶学特性进行研究,结果表明,固定化酶的优化制备工艺为菠萝皮渣纤维素与离子液体的质量比为3∶100,L-丝氨酸与菠萝皮渣纤维素的质量比为1∶1,戊二醛溶液体积分数为1%,交联时间为1.0 h。与游离菠萝蛋白酶相比,固定化菠萝蛋白酶具有更好的温度稳定性和酸环境稳定性。

Study on Immobilization of Bromelain by Modified Pineapple Peel Residue Cellulose

In order to explore the feasibility of modified cellulose as immobilization enzyme carrier,the extracted pineapple peel residue cellulose was uniformly modified with L-serine in ionic liquid and used to immobilize bromelain.The pineapple peel residue cellulose,modified pineapple peel residue cellulose and the immobilized enzyme were compared and characterized by Fourier transform infrared spectroscopy,thermogravimetric analyzer and X-ray diffraction spectrum.The results showed that the pineapple peel residue cellulose was successfully modified,the crystal structure was changed from celluloseⅠto celluloseⅡ.Bromelain was successfully immobilized on the modified pineapple peel residue cellulose,and the thermal stability of immobilized enzyme was higher than that of modified pineapple peel residue cellulose.The immobilization process and enzyme characteristics of the bromelain were studied.The results showed that the optimum preparation process of immobilized enzyme was that the mass ratio of pineapple peel residue cellulose to ionic liquidBmim]Cl was 3∶100,the mass ratio of L-serine to pineapple peel residue cellulose was 1∶1,the glutaraldehyde solution volume fraction was 1%,and the cross linking time was 1.0 h.Compared with free bromelain,immobilized bromelain had better temperature stability and acid environment stability.