Modified pectin as imprinting substrate to immobilize pectinase via both adsorption and crosslinking

Abstract

A broad-spectrum substrate-imprinted adsorption and crosslinking double immobilized pectinase (SDP) was prepared using a universal modified pectin obtained through enzymatic hydrolysis as the imprinting substrate. Its structure was characterized by infrared spectroscopy, circular dichroism, and scanning electron microscopy. The results showed that 1) cross-linking increased the Schiff base in SDP, 2) immobilization barely changed the secondary structure such as α-helix and β-sheet of SDP, and 3) adhesives were evenly distributed on the surface after immobilization. Studies on the enzymatic properties of SDP showed that the substrate imprinting significantly improved heat resistance and neutralization resistance of SDP. For example, the relative activity of SDP at 35 to 75 °C and at pH 4.4 to 6.5 was 5% and 15% more than that of the adsorption and crosslinking double immobilized pectinase (DP), respectively. In addition, after 8 cycles of use, the relative enzyme activity of SDP still reached 39.5%. Moreover, use of SDP decreased the cation demand in whitewater by 10% compared with DP. Overall, the use of a broad-spectrum substrate for imprinting to obtain SDP provides a new idea and method for using pectinase in in complex systems such as juice clarification and wastewater treatment.