Enzymatic Hydrolysis Reaction Of Ester In Reverse Janus Emulsion Microreactor Of (PEG_（aq）+Na₂SO_4（aq）)/Oil System

Reverse Janus emulsions mix immiscible reactants at the micro-nano scale to create multiple reaction interfaces and shorter mass transfer distance.Thus,reverse Janus emulsions accelerate the enzymatic hydrolysis of esters,which is a typical heterogeneous reaction.In addition,reverse Janus emulsions with inner aqueous environments possess biocompatibility,which is ideal places for enzyme catalysis reactions.In the present thesis,a reverse Janus emulsion microreactor is prepared by an aqueous two-phase system(ATPS)composed of polymer(PEG)and inorganic salt(Na2SO4)as the inner phase,vegetable oil(VO)as the external phase,and mixed surfactants of Tween 80 and Span 80 as emulsifiers.The effect of PEG and Na2SO4 content on the reaction is investigated in the emulsion microreactor.The morphology and stability of the droplet,the distribution and activity of the enzyme in the aqueous phase are explored by changing the composition of initial ATPS.In addition,the external phase of the emulsion is replaced by liquid paraffin.The effect of the initial composition of the internal ATPS on the enzymatic hydrolysis of VO is studied.The specific research contents are as follows:1.The partial phase diagram in PEG8000(aq)/Na2SO4(aq)system is plotted.The initial composition of the ATPS is adjusted based on the phase diagram.The influence of mass fractions of PEG8000 and Na2SO4 on the volume ratio and composition of separated equilibrium ATPS is explored.The droplet morphology,emulsion stability,enzyme distribution and activity in the reverse Janus emulsion are regulated by adjusting the initial ratio of ATPS.The reaction kinetic in the reverse Janus emulsion microreactor is further regulated.2.The regulation of PEG4000 and Na2SO4 mass fractions on the catalytic effect of reverse Janus emulsion microreactor is studied.The effects of the change of the proportion of the internal aqueous phase on the morphology of droplets,the stability of the emulsion,the distribution and activity of enzymes in the internal aqueous phase in the emulsion microreactor are studied,so as to elucidate the reasons for the change of catalytic effect of the emulsion microreactor.3.A series of emulsion microreactors of PEG4000/Na2SO4/liquid paraffin systems are prepared.The stability of the emulsion,the distribution and activity of the inner aqueous phase enzyme are realized by adjusting the mass fractions of PEG4000 and Na2SO4.The conversion and the kinetic process of the ester hydrolysis in the emulsion microreactor are further regulated.In addition,the universality of the reverse Janus emulsion microreactor is studied by changing the type of grease in liquid paraffin.