Uses of Paper Industry Cellulase Free Xylanases
Making paper from wood requires separation of wood fibres from each other (pulping) and then reforming them into a sheet. In trees, the wood fibres are glued together due to lignin, which needs to be degraded to get chemical pulp (alternatively mechanical pulp can be obtained by tearing the wood fibres apart). From the chemical pulp, the residual lignin is removed by bleaching to get a brighter pulp. Since chlorine is conventionally used in bleaching, effluents from' bleaching often contain toxic chlorinated compounds, which is an environmental hazard. Therefore, new techniques are being developed for pulp bleaching, where endoxylanases (cellulase free) are used (lignin-xylan complexes are found both in hardwood and softwood and can be degraded by cellulase free xylanases; presence of cellulase is avoided, since it may destroy the fibres).