Study On The Catalytic Effect Of Cyclodextrin On Enzyme

As a kind of efficient and environmentally friendly catalyst,enzyme has been widely used in food,chemical and other industrial fields.However,the instability and high cost of enzyme restrict its industrial application.Various methods have been used to improve the stability and activity of enzyme,and the additive method is attractive because of its high efficiency and simplicity.The external hydrophilic and internal hydrophobic cavity structure of ?-cyclodextrin(?-CD)can form an inclusion complex with enzyme,which would change the physical and chemical properties of enzyme,thus influence its catalytic performance.In this study,the effects of ?-CD on enzyme catalysis were explored with lipase and snail enzyme as research objects.The reaction mechanism was explored by spectroscopy.The main research contents were as follows:1.Effect of ?-CD on catalytic performance of lipase(1)The hydrolysis reaction of hemp seed oil to prepare fatty acids was studied.When ?-CD was used as an additive,the catalytic activity of Candida sp.99-125 and Lipozyme TLIM were increased significantly(p<0.05).In the Candida sp.99–125 group,the composition of linolenic acid(18.27%,w/w)in the free fatty acids was increased under the action of ?-CD compared with the control(15.18%,w/w,p < 0.05).This indicated that ?-CD could not only improve the catalytic activity but also affect the hydrolytic selectivity of lipase Candida sp.99–125.(2)The effect of ?-CD on the thermal stability of Candida sp.99-125 lipase had been investigated by olive oil emulsification method.After reacting 60 min,the residual activity of Candida sp.99–125(55.56%,p < 0.05)was increased significantly in ?-CD-treated group compared with the control group(38.28%).This indicated that the thermal stability of Candida sp.99-125 lipase was significantly increased.At the same time,?-CD could increase the recycling rate of Candida sp.99-125 lipase.Under the same batch,the hydrolysis activity of the experimental group was significantly higher than that of the control group.(3)Spectral analysis(ultraviolet spectroscopy and fluorescence spectroscopy)showed the maximum absorption peak decreased in a regular manner with increasing concentrations of ?-CD.This indicated that ?-CD interacted with Candida sp.99-125 lipase to form a clathrate,which changed the microenvironment and spatial conformation of lipase.2.Effect of ?-CD on the catalytic activity of snail enzyme(1)In order to obtain the snail enzyme with the highest yield and activity,the snails were pretreated with starvation.The results showed that the activity of snail enzyme was the highest after 3 days of starvation,and the enzyme activity was 267.63U/g.The effect of ?-CD on snail enzyme activity and thermal stability found that ?-CD concentrations had no significant effect on the activity of snail enzyme,but the thermal stability was significantly improved.(2)Spectroscopic analysis showed that the ultraviolet and fluorescence spectra intensity of snail enzyme decreased with the concentrations of ?-CD increased.This indicated that ?-CD interacted with the side chain or amino acid residue of the enzyme molecule,which changed the spatial conformation of the snail enzyme and ultimately affected its catalytic performance.This study preliminarily explored the effects of ?-CD on lipase and snail enzyme activity and thermal stability,and investigated its interaction mechanism by spectroscopy.The role of ?-CD in lipase catalyzed hydrolysis of hemp seed oil further was also explored,which provided a theoretical basis for expanding the industrial production of enzymes.