Improvement of enzyme transport in wood chips for thermomechanical pulp refining

Wood chips, macerated wood chips and coarse wood fibers were compressed and allowed to decompress in enzyme solutions prior to mechanical refining. Electrical consumption in refining was monitored in order to investigate potential energy savings during refining. Wood treated with Celluclast® 1.5 L showed a reduction in refining energy up to a 36%. Canadian Standard Freeness was used to track degree of refining. Decompressing in the enzyme solution gave a 15% reduction in energy consumption compared to having the already decompressed substrate treated with enzymes. This indicated that improving the transportation of enzymes into wood chips would further enhance the enzyme effect on refining. In this study, confocal laser scanning microscopy (CLSM) was used to track a dyed dextran of 70k molecular weight (the size of some of the larger enzymes) which was used as molecular probe to investigate the potential added penetration of enzymes induced by compression/decompression in the selected chip sizes.