Study On The Behavior Of Alkaline Protease At Interfaces

In this paper,we had used the enzyme activity analysis,dynamic light scattering,interfacial tension and interfacial dilatational rheology to study the interfacial behavior of alkaline protease solution changed with the placement time increased.Also,we had used different adsorption models to fit the equilibrium surface tension of alkaline protease at air/water and hexane/water interfaces,while the adsorption of alkaline protease at the two different interfaces was compared.This paper first mainly described the changes of the enzyme activity,particle size,zeta potential,interfacial tension and interfacial dilatational rheology of alkaline protease solution with different mass fraction were studied.In this experiment,we mainly measured the changes of alkaline protease activity,particle size,zeta potential,interfacial tension and interfacial dilatational rheology with different concentrations.With the increase of the time and the mass fraction of the alkaline protease solution,the size of the protease molecules in the solution increased,the zeta potential decreased,the alkaline protease solution was unstable and the protease molecules in the solution tended to aggregate.The enzymatic activity of the alkaline protease solution decreases with the aggregation of alkaline protease molecules in the solution.With the aggregation of enzyme molecules in the bulk solution of alkaline protease,the kinetics of the diffusion of alkaline protease molecules from the bulk to the interface changed.The value of equilibrium interfacial tension of alkaline protease solution increased;also the time required for the adsorption reached equilibrium at the interface increased too.It decreased that the elasticity and mechanical strength of the interface membrane formed by the alkaline protease at the air/water interface.The second part of this paper mainly studied the adsorption of alkaline protease solution with different concentrations at air/water interface and hexane/water interface.In this part,the adsorption of alkaline protease solution with different concentrations at air/water and hexane/water interface was compared by measuring the interfacial tension and interfacial dilatational rheology and fitting the equilibrium interfacial tension of alkaline protease at air/water and hexane/water interfaces with different adsorption models.First,the change of the interfacial tension of alkaline protease solutions with drop age at air/water interface and hexane/water interface was measured.Secondly,the equilibrium interfacial tension of alkaline protease solutions at the air/water and hexane/water interface was fitted with different adsorption models.In addition,the change of modulus of alkaline protease solutions with different mass fraction at air/water and hexane/water interface was determined in a certain frequency,further studied and compared the interface properties of alkaline protease at air/water and hexane/water interface.