蛋黄-壳结构Fe3O4@SiO2@PMO磁性微球的制备及对漆酶的固定化

以蛋黄-壳结构的Fe₃O₄@SiO₂@PMO磁性微球作为载体, 采用交联法对漆酶进行固定, 考察了戊二醛浓度等对固定效果的影响, 并对固定后漆酶的活性进行了研究. 结果表明, 蛋黄-壳结构的磁性微球负载漆酶仅需6 h, 磁性微球对漆酶的固载量高达475 mg/g. 固定后漆酶的稳定性显著提高, 在pH=2.5~4.5的强酸性条件下, 固定后漆酶酶活仍可保持70%以上, 即使温度升高至60 ℃, 固定后漆酶的相对酶活仍保持65%以上. 这说明漆酶经所合成的材料固定后, 其耐酸和耐热能力都明显优于游离漆酶. 包覆的Fe₃O₄粒子使得材料很容易经磁铁分离法回收, 固定后漆酶经磁分离循环使用10次后仍然能保留85%的酶活, 具有良好的可操作性和稳定性, 有效降低了漆酶的使用成本.

Preparation of Yolk-shell Fe3O4@SiO2@PMO Magnetic Microspheres for Laccase Immobilization†

Yolk-shell Fe₃O₄@SiO₂@PMO magnetic microspheres were prepared and used to immobilize laccase using glutaraldehyde as the crosslinking agent. The influence of some experimental factors, such as glutaraldehyde concentration, crosslinking time and immobilization time, on laccase immobilization were investigated. The largest immobilization amount of laccase in the Fe₃O₄@SiO₂@PMO microspheres is 475 mg/g. After immobilization, the laccase could survive in harsh environment, showing relative enzyme activities of 70% and 65% at pH=2.5—4.5 and 60 ℃, respectively. This means immobilization on Fe₃O₄@SiO₂@PMO could afford higher stability than bare laccase. Besides, immobilized laccase could be recycled easily via simply magnetic separation, with activity retention of 85% even after 10 times recycle.