Valorisation of wheat straw into paper with improved quality characteristics using ultrafiltered xylano-pectinolytic pulping approach.

Abstract

This study has been conducted to assess the pulpability of ultrafiltered pectinase and xylanase in pulping of wheat straw. Best biopulping conditions were achieved using 107 and 250IU of pectinase and xylanase, respectively, per gram of wheat straw, 180min of treatment period, one gram: 10 m1 material to liquor ratio, 8.5 pH and 55°C temperature. Ultrafiltered enzymatic treatment improved the pulp yield (6.18%), brightness (17.83%), along with reduced rejections (61.01%) and kappa number (16.95%) as compared to chemically synthesized pulp. Biopulping of wheat straw saved 14% alkali dose, with nearly same optical properties, as obtained under 100% alkali dose. Bio-chemically pulped samples resulted an increase in breaking length, tear index, burst index, viscosity, double fold and Gurley porosity by 6.05%, 18.64%, 26.42%, 7.94%, 21.6% and 15.38%, respectively, in comparison to control pulp samples. Bleached-biopulped samples showed an improvement in breaking length, tear index, burst index, viscosity, double fold number, and Gurley porosity by 7.39%, 3.55%, 28.82%, 9.1%, 53.66%, and 30.95% respectively. Thus, biopulping of wheat straw with ultrafiltered enzymes lowers alkali consumption and also improves the paper quality. This is the first study reporting, eco-friendly biopulping, for producing better quality wheat straw pulp, using ultrafiltered enzymes.