Immobilization of Aspergillus niger xylanase on magnetic latex beads.

Xylanase from Pectinex 3XL was purified 70-fold by precipitation with an enteric polymer, Eudragit S-100. The purified xylanase was immobilized on magnetic latex beads via carbodi-imide coupling. The immobilized preparation showed 80% of the total activity bound to the beads. The pH optimum remained unchanged at 6.0 and the Km increased from 0.25 g/100 ml (free enzyme) to 0.39 g/100 ml on immobilization. Immobilization resulted in significant thermal stability at 60 degrees C. The time course of hydrolysis of xylan at 60 degrees C by free enzyme as well as immobilized enzyme was also studied.