Immobilization of pectinase on polyethyleneimine-coated pulp fiber for treatment of whitewater from papermaking

After being coated with polyethyleneimine (PEI), pulp fiber was used as carrier for pectinase. When PEI concentration, enzyme concentration and pH of enzyme solution were 0.01% (w/v), 0.25% (v/v) and 7, respectively, the resultant immobilized enzyme exhibited the highest enzymatic activity as about 670 μg min−1 g−1. Higher thermo and pH stabilities than those of the free enzyme were achieved after immobilizing the enzyme on PEI-coated pulp fiber. Furthermore, the bound pectinase effectively decreased the cationic demand of whitewater in papermaking under the practical industrial conditions and still maintained high activity after operating repeatedly for 8 batches. The results presented that through a simple, facile and inexpensive method, pectinase can be effectively immobilized on pulp fiber and the immobilized pectinase showed the potential application in practical industrial treatment of whitewater in papermaking industry.