Co-Immobilization of pullulanase, glucoamylase and glucose isomerase together with cross-linked enzyme aggregates: Fructose conversion from three enzymes and starch in one step

Abstract

In this study, in order to obtain fructose syrup from starch, pullulanase (PUL), glucoamylase (GA) and glucose isomerase (GI) were immobilized together with cross-linked enzyme aggregates (CLEAs), and named as 'combi-CLEAs'. The values of Vmaxand Kmfrom the kinetic parameters of combi-CLEAs [(GA + PUL) + GI] were found as 12      U g-1 and 0.1157 mg ml-1 in optimum conditions, respectively. After 50 uses, it was observed that the remaining activity of combi-CLEAs [GA + PUL + GI] was preserved at 46%. The thermal stability of combi-CLEAs [GA + PUL) + GI] was observed to be 44% and 30%, respectively, at 60 and 80 ° C after 24 hours. At the end of 30 days, the storage stabilities of combi-CLEAs [(GA + PUL) + GI] was determined as 56% and 13% at the temperatures of 4 and 25°C, respectively.