Enzymatic hydrolysis of konjac glucomannan(KGM)by β-mannanase was studied at constant mass ratio of enzyme to substrate to investigate the reaction-diffusion mechanism.By using size exclusion chromatography(SEC),th...Enzymatic hydrolysis of konjac glucomannan(KGM)by β-mannanase was studied at constant mass ratio of enzyme to substrate to investigate the reaction-diffusion mechanism.By using size exclusion chromatography(SEC),the changes in molecular weight distribution of KGM were followed during the process of hydrolysis.When the ratio of enzyme to substrate was constant,the changes in molecular weight at different KGM concentrations were remarkably different,which showed that the reaction depended on the diffusion of enzyme.The changes in molecular weight showed a zero-order kinetics.Integrating the empirical reaction kinetics and diffusion characteristics,a reaction-diffusion model was established from a series of chromatographic results.But the degradation rate was shown to be greatly affected by the diffusion of enzyme as well as the concentration of substrate.This equation of reaction kinetics indicated the importance of diffusion,and the experimental data can be well predicted at semi dilute concentrations of KGM.展开更多
A simple method was presented for obtaining good approximate solutions of diffusionreaction boundary value problems in immobilized enzyme.Based on approximate solutions for diffusionreaction problems,the mathemati...A simple method was presented for obtaining good approximate solutions of diffusionreaction boundary value problems in immobilized enzyme.Based on approximate solutions for diffusionreaction problems,the mathematical expressions for calculating effectiveness factor of immobilized enzyme were proposed.Calculations of effectiveness factor were made with MichaelisMenten kinetic expression for spherical immobilized enzyme pellet.The results show that the agreement of approximate solution of effectiveness factor with numerical solution obtained by numerical method is satisfactory in a wider parameter range.The presented method for calculatin effectiveness factor of immobilized enzyme is simple and the calculation is fast.展开更多
For high viscosity bulk-copolymerization of octamethylcyclotetrasiloxane and amino-silicone monomer, a multisyphon flow physical model was established.Based on the free volume and chemical reaction kinetic theories, a...For high viscosity bulk-copolymerization of octamethylcyclotetrasiloxane and amino-silicone monomer, a multisyphon flow physical model was established.Based on the free volume and chemical reaction kinetic theories, a new computational model was developed to simulate the multisyphon flow model. As to the new model, the united influence of reaction and diffusion was reviewed and analyzed. The new model was used to simulate bulk- copolymerization of octamethylcyclotetrasiloxane and amino-silicone monomer and agreed well with the results.展开更多
文摘Enzymatic hydrolysis of konjac glucomannan(KGM)by β-mannanase was studied at constant mass ratio of enzyme to substrate to investigate the reaction-diffusion mechanism.By using size exclusion chromatography(SEC),the changes in molecular weight distribution of KGM were followed during the process of hydrolysis.When the ratio of enzyme to substrate was constant,the changes in molecular weight at different KGM concentrations were remarkably different,which showed that the reaction depended on the diffusion of enzyme.The changes in molecular weight showed a zero-order kinetics.Integrating the empirical reaction kinetics and diffusion characteristics,a reaction-diffusion model was established from a series of chromatographic results.But the degradation rate was shown to be greatly affected by the diffusion of enzyme as well as the concentration of substrate.This equation of reaction kinetics indicated the importance of diffusion,and the experimental data can be well predicted at semi dilute concentrations of KGM.
文摘A simple method was presented for obtaining good approximate solutions of diffusionreaction boundary value problems in immobilized enzyme.Based on approximate solutions for diffusionreaction problems,the mathematical expressions for calculating effectiveness factor of immobilized enzyme were proposed.Calculations of effectiveness factor were made with MichaelisMenten kinetic expression for spherical immobilized enzyme pellet.The results show that the agreement of approximate solution of effectiveness factor with numerical solution obtained by numerical method is satisfactory in a wider parameter range.The presented method for calculatin effectiveness factor of immobilized enzyme is simple and the calculation is fast.
文摘For high viscosity bulk-copolymerization of octamethylcyclotetrasiloxane and amino-silicone monomer, a multisyphon flow physical model was established.Based on the free volume and chemical reaction kinetic theories, a new computational model was developed to simulate the multisyphon flow model. As to the new model, the united influence of reaction and diffusion was reviewed and analyzed. The new model was used to simulate bulk- copolymerization of octamethylcyclotetrasiloxane and amino-silicone monomer and agreed well with the results.
