银纳米粒子在木瓜蛋白酶固定化中的应用

Application of Silver Nanoparticles in Immobilization of Papain

通过超声条件下正硅酸四乙酯与γ-氨丙基三乙氧基硅烷的同步水解,一步制备了带氨基的二氧化硅微球,并在其表面沉积了银纳米粒子.以此负载银的二氧化硅微球作为载体固定木瓜蛋白酶,研究了银纳米粒子负载量对木瓜酶固定化的影响,考察了固定化木瓜蛋白酶的性能.结果表明,当载体的银负载量为0.68%时,固定木瓜蛋白酶活回收率达到最高,比使用未负载银的载体提高了188%;该固定酶比游离酶具有更好的热稳定性,在重复使用20次后仍保持原有酶活的43%,4℃下储存2个月后酶活基本没有下降.

Silica spheres with amine groups were synthesized in a one-step process by synchronous hydrolysis of tetraethylorthosilicate （TEOS） and N-（2-aminoethyl）-3-aminopropy-triethoxysilane （APTES） under a ultrasound condition, and then silver nanoparticles were deposited on the surface of spheres. These silica spheres coated with silver nanoparticles were used as the carrier in immobilization of papain. The influence of silver nanoparticles on immobilized papain was studied. The highest activity recovery rate was obtained using carrier with 0.68% silver nanoparticles, and it increased 188% than that using the carrier without silver nanoparticles. The performance of the fixed enzyme was also examined. This immobilized papain was more resistant to heat than free enzyme. It maintained 43% activity after using by 20 times repeatedly, and the activity dropped exiguously after it was preserved at 4℃ for 2 months.