Controlled Construction Of Monolithic Enzymatic Micro-reactor For Environmental Catalysis

Enzyme immobilization is a technology that restrict enzyme in a confined space by supports which could be used in enzymatic process.Enzyme immobilization exerted merits such as enviromental friendly,high effectivity and selectivity which have been applied in environment protection,pharmecutical synthesis,fine chemical industry,etc.An effective immobilized enzyme should have to meet the needs of both catalytic function including activity,selectivity,stability,etc and non-catalytic function such as recyclability,controllability,etc.In this study,based on the crystallization-induced assembly of LPEI,the surface chemical/physical structure of monolithic supports was re-constructed by self-assembly and bio-mineralization.And two types of monolithic enzymatic micro-reactors:packed enzymatic micro-reactor and film enzymatic micro-reactor were constructed via physical adsorption and entrapment.The intrinsic relationship of catalytic function and non-catalytic function was further investigated,i.e.the influence of chemical and physical structure of enzyme-carrier on enzyme loading capacity,catalytic activity and stabilities.Finally,the high immobilization efficiency of enzyme,great catalytic activity and stabilities were achieved.Furthermore,the application research of these two monolithic enzymatic micro-reactors in wastewater treatment and CO₂ conversion were also conducted.The details of this study were summarized as follows:a)Based on cordierite honeycomb（cordierite-H）,the packed enzymatic micro-reactor was constructed.The horseradish peroxidase（HRP）was took as a model enzyme,and the effect of nano-porous LPEI layer and silica layer on enzymatic property was systematically studied.Furthermore,the catalytic function and non-catalytic function were co-optimized.As a result,the monolithic support after re-construction exhibited higher immobilization efficiency（83.75%）and activity recovery（55.33%）.After mineralization,the stabilities of the packed enzymatic micro-reactor were significantly improved.Moreover,the packed enzymatic micro-reactor was applied in dye degradation and the degradation efficiency of dye was up to 53.30%.b)Based on polyethylene（PE）film,the film enzymatic micro-reactor was constructed.The glucose oxidase（GOD）was took as a model enzyme,the influence of chemical/physical structure and reaction condition on enzymatic property was studied.Then the influence mechanism of gas-liquid-solid interace on enzymatic activity of enzymatic micro-reactor was revealed and finally the enzymactic activity was improved.After the formation of nano-fiberous LPEI layer,the permeability of film was not effect by the LPEI layer.Meanwhile,the activity of gas involved enzymatic reaction was significantly improved.In consequence,the immobilization efficiency and glucose coversion capacity（reach equilibrium）were 66.70%and 15.58μmol,respectively.Ultimately,the enzymatic micro-reactor for CO₂ conversion was constructed via the immobilization of carbonic anhydrase on the functionalized film.CO₂ could be conversed to Ca CO₃ effectively and the Ca CO₃ production capacity was up to 79 mg（cm²）^-1 in a minute.