Xylanase from Penicillium meleagrinum var. viridiflavum - a potential source for bamboo pulp bleaching

The effect of enzymatic process on pulp bleaching using a potential lignolytic fungus Penicillium meleagrinum has been investigated in order to minimize the consumption of chemicals in bleaching process. Xylanase enzyme extracted from P. meleagrinum was studied and the maximum xylanase production by P. meleagrinum was recorded as 5.74 U/mL at 30 degrees C and at 5.5 pH. The extracted xylanase was applied to the unbleached bamboo pulp alone or in combination with hydrogen peroxide to find out the efficacy of the enzyme on pulp bleaching. Xylanase pre-treatment can remove a considerable amount of lignin from unbleached pulp which can further be reduced by giving a treatment with 2% hydrogen peroxide. Xylanase pre-treated peroxide bleaching reduces lignin content from 10.55% to 3.25% in unbleached bamboo pulp. The kappa number of pulp decreases from 13.50 to 8.50 with the increase of pulp brightness 68-69%, viscosity 8.94 cP and crystallinity of the pulp cellulose to 62.05%. Scanning electron micrographs reveal uniform fibre with occasional pores and cracks on the surface. The results of the present study have been found encouraging which may aid in the development of new cleaner and alternative method of bleaching for pulp and paper industry. (C) 2015 Elsevier Ltd. All rights reserved.