Recycled fibers have become increasingly important as raw material in the pulp and
paper industry. Although utilization of secondary fibers has environmental and economical
advantages, unfortunately the deteriorated drainability of secondary fibers causes
decreased productivity. In this work, two commercial Trichoderma cellulase enzyme
preparations were used to improve pulp properties of recycled paper. A blend of various
cellulase components (Pergalase A40) was compared with
endoglucanase III (IndiAge Super L) based on their effect on drainage, water retention
value, fiber length distribution and paper properties (air permeability, tensile index,
burst index, tear index). Enzyme characteristics were investigated in order to establish
the industrial applicability. IndiAge Super L containing only EG III proved to be
more stable than Pergalase A40 against fluctuation of temperature and pH.
Experimental design (cross-classification) was used to examine the influence of enzyme
dosage and treatment time on drainage. The effects of enzymatic treatments on pulp
and paper properties showed that the type of enzyme component is probably very important.
Moreover, existence or absence of cellulose-binding domain might play a determinative
role. (C) 2003 Elsevier B.V. All rights reserved.