Production of a recombinant xylanase in plants and its potential for pulp biobleaching applications

The purpose of this study was to produce recombinant xylanase in transgenic plants and to test its potential application for pulp bleaching. The xynII xylanase gene from Trichoderma reesei was inserted into the Arabidopsis genome. Many transgenic plants produced biologically active XYNII and accumulated in leaves at level of 1.4–3.2% of total soluble proteins. The bleaching ability of XYNII on Kraft pulp was demonstrated by a reduction in the kappa number and the residual lignin contents. The bleaching efficiency of transgenic plant produced XYNII was similar to commercial xylanase on unbleached Kraft pulp. The effect of xylanase treatment on Kraft pulp was also investigated by SEM. Clear physical change on the pulp fiber surface was observed and was related to the amount xylan removed and microfibrils were visible on the fiber surface. This report demonstrates the potential application of plant produced recombinant xylanase for pulp and paper bleaching.