LOCATION OF XYLANASE AND MANNANASE ACTION IN KRAFT FIBERS

The effects of the fibre surface on the action of xylanase and mannana se on pine and birch kraft pulps, and the location of enzymatic action in the fibres were studied using sequential enzymatic treatment and m echanical peeling. The enzymatic hydrolysis of the outer surface of th e fibres was only partial in spire of the goon accessibility of the su rface material. The relatively high content of lignin in the surface m aterial probably limited the action of the enzymes either physically o r chemically. The intensities of the action of xylanase and mannanase at the outer surfaces of the pulp fibres were, however; different. The location of the mannanase action was more concentrated on the surface of the pine fibres whereas the xylanase action was distributed almost uniformly between the surface and the inner cell walls of both pine a nd birch fibres. The difference in the location of action of rite enzy mes was probably due, at least in part, to their different molecule si zes and structures and consequently, different mobilities in the fibre s.