固载过氧化氢酶微球清除家庭漂白后残留过氧化氢的研究

Removal of residual hydrogen peroxide after bleaching by microspheres containing catalase

利用仿生矿化法制备了固载过氧化氢酶的碳酸钙微球,研究了该载酶微球的包封情况、在苛刻环境中的稳定性和清除漂白纱布后残留过氧化氢的效果。结果表明,该载酶微球粒径约11μm,孔径为5.53 nm,能有效封装住过氧化氢酶;在过氧化氢酶质量浓度为0.15 mg/m L的条件下,该微球对过氧化氢酶具有最高负载量为24.26 mg/g,此时酶包封率为98%,酶活力保留率为72%。该载酶微球与游离酶相比提升了热稳定性(80℃条件下仍能保留38.99%的相对酶活力)、改变了过氧化氢酶对不同pH环境耐受能力的趋势(最适酶活力pH值由pH 8偏移至pH 11),提升了耐表面活性剂性质(在十二烷基硫酸钠环境中仍保留了85.82%的相对酶活力)。且该载酶微球能在25 min完全清除漂白纱布后残留的过氧化氢。

Calcium carbonate microspheres containing catalase were prepared by the method of bionic mineralization.The size and pore size of the enzyme-carrying microspheres were measured;the encapsulation efficiency,loading capacity and stability of the enzyme-carrying microspheres in harsh environments were studied;11 relative enzym e activity/%the removal of residual hydrogen peroxide from the gauze after bleaching was studied.The results show that the enzymecarrying microspheres have a particle size of approximately 11μm.From the nitrogen adsorption-desorption isotherm and pore size distribution diagram,it can be seen that CAT@CaCO_(3) microspheres have uniformly distributed pores(approximately 5.53 nm),which can well encapsulate catalase(approximately diameter 6 nm×10 nm),allowing the substrate H_(2)O_(2) and the product H2O to diffuse freely.Under the condition that the mass concentration of catalase is 0.15 mg/m L,the microsphere has a maximum load of 24.26 mg/g for catalase.Meanwhile,the enzyme encapsulation rate is 98%,and the enzyme activity retention rate is 72%,indicative of the mildness of the method of enzyme immobilization.Compared with free enzymes,the enzyme-carrying microspheres have improved thermal stability(38.99%of relative enzyme activity can still be retained at 80℃)and have changed the trend of catalase tolerance to different pH environments(the optimal pH for the enzyme activity shifts from pH 8 to pH 11).This phenomenon may be ascribedto the mineralization and fixation of calcium carbonate changing the conformation of the enzyme.To a certain extent,the conformation of CAT is changed,resulting in a different tendency of p H tolerance from free enzymes.In addition,the anti-surfactant performance of the enzyme-carrying microspheres is improved(85.82%of relative enzyme activity remains in the presence of sodium lauryl sulfate).The reasons might be that the calcium carbonate mineral shell can stabilize the three-dimensional structure of the enzyme during the process of immobilizing the enzyme,resulting in the enhanced stability of the immobilized enzyme.Finally,the enzyme-carrying microspheres can completely remove the residual hydrogen peroxide from the gauze after bleaching within 25 min,which has a faster removal rate than the free enzyme(35 min).