Enzyme activity recovery from secondary fiber treated with cellulase and xylanase

One of the major problems with implementing biotechnical processes in the recycled paper industry, such as enzyme-enhanced deinking and enzymatic enhancement of pulp drainage properties, is the cost of commercial enzyme preparations. Thus, several factorial studies were performed to determine if enzyme activity can be successfully removed from simulated recycled fiber (once-dried, bleached hardwood and softwood kraft fiber) treated with low concentrations (0.2% or 2.0% on oven-dry fiber) of cellulase or xylanase. Enzyme activity recovery was accomplished by washing treated fiber with dilute NaOH in combination with a low concentration of the nonionic surfactant Tween 80 under a variety of mild conditions. Various cellulase activities i.e., endoglucanase, exoglucanase, and filter paper, can be effectively recovered depending on the washing conditions, the cellulase charge, and the fiber type. Xylanase activity was effectively recovered from softwood, but not hardwood. The results suggest that enzyme activity recovery may be a possible means of decreasing the operating costs for biotechnical processes in the paper industry.