Preparation Of Novel Carrier And Its Application In Pollutant Degradation And Sample Pretreatment

In recent years,compared to free enzyme,immobilized enzyme has attracted widespread attention in many branches fields for its'high activity,enhanced stability,and reusability,and more and more functional materials have begun to be explored for enzyme immobilization.There is no doubt that enhanced stability and improved activity have been achieved.However,for practical applications,the synthesis and modification of materials suffered from time-consuming,tedious operation,or consumption of hazardous solvent.Therefore,due to the combination of benefits in environmental friendliness,mechanical simplicity,lower energy consumption and ease of operation,three different functional materials for single-enzyme and dual-enzyme immobilized systems were proposed in this thesis.Then the activities,stabilities,and their applications of immobilized enzyme were investigated,respectively.1.The environmentall-friendly monolithic material-melamine sponge?MeS?coordinated with Fe³⁺was explored as laccase carrier.The 3D structure of MeS can enhance the enzyme loading amount up to 180 mg/g.The immobilized laccase also showed improved catalytic efficiency,enhanced stability and reusability.Then the immobilized laccase was successfully applied to the degradation of dyes and other micropollutants,which has shown higher efficiency than free laccase in the large-scale decolorization of dyes and showed up to almost 100%removal of2,4,6-trichlorophenol?2,4,6-TCP?and sulfisoxazole.2.We report a solvent-free approach based on mechanical grinding to prepare a magnetic zeolite imidazolate framework-8?ZIF-8?composite,which exhibited high lipase loading with 95 mg/g.To improve catalytic efficiency for water-insoluble substrate,the immobilized lipase with an appropriate water contact angel??ow?was explored as a stabilizer of Pickering emulsion on the oil-water interface.In this interfacial biocatalytic system,the immobilized lipase combined both emulsifier and catalytic property based on interfacial activation at the interface of both phases and showed 2.48 times higher catalytic efficiency than free lipase and strong tolerance for organic media.3.Hydrophilic MOFs?ZIF-90?were chosen as dual-enzyme carrier to construct a dual-microreactor with co-immobilized trypsin and?-chymotrypsin,and a stepwise immobilization method was presented to achieve the hierarchical distribution of the dual enzymes.First,a biomimetic method was introduced to prepare a ZIF-90composite encapsulated with?-chymotrypsin.Then the surface immobilization of trypsin was achieved though the biomacromolecules affinity towards the imidazole-containing surface arising from intermolecular hydrogen bonding and hydrophobic interactions.The activity,stability and reusability of immobilized?-chymotrypsin and trypsin were investigated,and the dual enzyme system was applied for the digestion of BSA.After a series of determinations,the dual-enzyme system showed better catalytic efficiency than free mixed?-chymotrypsin and trypsin.