Valorization of Agro-industrial Residue-Rice Straw for Manufacturing Better Quality Paper Using Cleaner, Ultrafiltered Xylano-Pectinolytic Enzymatic Pulping Strategy.

In this study, eco-friendly pulping of rice straw for manufacturing better quality paper is presented, using ultrafiltered xylanase and pectinase enzymes. The optimum conditions of ultrafiltered biopulping were, xylanase:pectinase dose 300:105 IU/g, treatment time 180 min, pulping consistency 10%, temperature 55 °C and pH 8.5. The ultrafiltered biopulping resulted in higher residual alkali content (29.17%). The kappa number, rejects, total solids reduced by 14.71%, 15.85%, 7.89%, respectively. In order to attain the approximately similar optical properties, as obtained with conventional pulping, ultrafiltered biopulping of rice straw resulted in 12% reduction in toxic pulping chemical and also improved the strength of handsheets with breaking length (16.08%), burst index (27.53%), tear index (4.36%), double fold (40%), gurley porosity (20.62%) and viscosity (11.30%). The ultrafiltered biopulping also reduced the consumption of bleaching chemical dose. The various strength related properties of biopulped (with 12% reduced alkali dose) and bleached rice straw pulp samples were significantly higher than 100% chemically treated pulp samples with breaking length (17.13%), burst index (21.16%), tear index (5.68%), double fold (39.58%), gurley porosity (25.81%) and viscosity (28.57%). This is the first report demonstrating the reduction of chemical dose in pulping and as well as in bleaching of rice straw along with production of better quality paper. [ABSTRACT FROM AUTHOR]