Study On Immobilization Techniques Of Jerusalem Artichoke Fructan Exohydrolase ?(Ht1-FEH?)

Jerusalem artichoke fructan exohydrolase ? has good ability for degrading fructan into fructose.However,the shortcomings of free enzyme limited its application due to poor stabilities,easy change and hard recovery.Compared with free enzyme,the immobilized enzyme has more advantages,especially for excellent stability,easy operation and recovery and low cost.In this paper,two methods were adopted for immobilized Jerusalem artichoke fructan exohydrolase(Ht1-FEH ?).First,we selected anion exchange resins D201 as carriers and glutaraldehyde as the crosslinking agent and immobilized by absorption-crosslinking method;Second,we selected sodium alginate as carriers and immobilized by embedding method.The optimum conditions for immobilized enzyme(Ht1-FEH?)were determined,and the properties of free enzyme(Ht1-FEH?)and immobilized enzyme(Ht1-FEH?)were compared.Based on our study,the method of absorption-crosslinking for immobilized enzyme has more advantages than embedding method.The main experimental results are as of follows:1.The optimum conditions for immobilized enzyme(Ht1-FEH ?)by absorption-crosslinking method were listed here:the weight of resins is 0.2g;the pH value of sodium acetate buffer is 4.5 and the amounts of enzyme is 0.1ml(the protein content is 0.34mg);the absorption time needs about 3 hours;the absorption temperature is 40?.the final concentration of glutaraldehyde solution is 0.125%and the cross-linking time needs about 2 hours and the temperature is 10?.The recovery of immobilized enzyme can reach to 73.53%under the above conditions.The properties of enzyme(Htl-FEH ?)was immobilized under the optimum conditions.We found that the optimum working temperature of immobilized enzyme(Ht1-FEH? at 40?,whereas the free enzyme(Ht1-FEH?I)at 35 ?.The optimum working pH of immobilized enzyme(Ht1-FEH?)was 6.5,whereas the free enzyme(Ht1-FEH?)was 6.0.2.The optimum conditions for immobilized enzyme(Ht1-FEH?)by embedding method were listed here:the optimum sodium alginate and calcium concentration is 2%and 1.5%,the optimum amounts of enzyme is 0.3ml(the protein content is 1.02mg),and the time of immobilization is 2h.Under these optimum conditions,the recovery of the immobilized enzyme can reach to 53.60%.The properties of enzyme(Htl-FEH ?)was immobilized under the optimum conditions,and found that the optimum working temperature of immobilized enzyme(Htl-FEH ?)at 35?,which is same with free enzyme(Htl-FEH?).The optimum working pH of immobilized enzyme(Htl-FEH ?)was 7.0,whereas the free enzyme(Htl-FEH?)was 6.0.3.Based on comparison of the results by these two immobilized method,we obtained the results:the immobilized enzyme(Htl-FEH ?)by absorption-crosslinking method has more advantages than by embedding method due to its recovery,operation and storage stability and could have potential in industry application.