多级孔Cr_(2)O_(3)固定化酶的制备及其应用研究

Preparation and Application of Immobilized Enzymes Based on Cr_(2)O_(3) with Hierarchical Porous Structure

针对酶在固相载体上固载后催化活性降低和底物传质阻力增大等问题,基于Cr-MOF前驱体,采用“自牺牲模板”策略设计制备得到两种具有介孔-微孔结构的多级孔Cr_(2)O_(3)(MHCr_(2)O_(3))材料,分别为MHCr_(2)O_(3)-400和MHCr_(2)O_(3)-600。以“聚多巴胺(PDA)”仿生膜对这两种材料表面进行功能化修饰后用以负载辣根过氧化物酶(HRP)构筑得到HRP@PDA@MHCr_(2)O_(3)固定化酶。负载后酶分子的热稳定性和重复使用性显著提高,70℃时1 h后HRP@PDA@MHCr_(2)O_(3)-400和HRP@PDA@MHCr_(2)O_(3)-600仍分别能保持98.0%和92.7%的催化活性,而相同条件下游离酶仅能保持不足20%的催化活性。经过10次重复使用,固定化酶仍能保持接近100%的催化活性。将固定化酶用于模拟浮选废水中苯胺黑药和丁铵黑药的降解时,在30 min内浓度为30 mg/L的苯胺黑药降解率可达70%以上,浓度为30 mg/L的丁胺黑药降解率可达60%以上。

In view of the problems such as the reduction of the catalytic activity and the increase of the mass transfer resistance of the substrate when the enzyme is immobilized on the solid phase carrier,two kinds of MOF-derived hierarchical porous Cr_(2)O_(3)materials with mesoporous and microporous structure(MHCr_(2)O_(3)-400 and MHCr_(2)O_(3)-600)were prepared based on thermolysis of Cr-MOF using the"self-sacrificing template"strategy.The surface of such materials were functionally modified with"polydopamine(PDA)"bionic membrane for entrapping horseradate peroxidase(HRP).The thermal stability and reusability of the enzyme molecules were significantly improved after loading.After 1 h incubation at 70℃,HRP@PDA@MHCr_(2)O_(3)-400 and HRP@PDA@MHCr_(2)O_(3)-600 retained 98.0%and 92.7%of the initial activity compared with less than 20%retained by free HRP.After 10 cycles,the catalytic activity was still close to 100%.When immobilized enzyme was used for degradation of aniline aerofloat and ammonium dibutyl dithiophosphate in wastewater,the degradation rate of aniline aerofloat at 30 mg/L and ammonium dibutyl dithiophosphate at 30 mg/L could reach more than 70%and 60%respectively within 30 min.