Valorization of wheat straw into paper by ultrafiltered enzymatic bleaching approach.

In this study, the potential of ultrafiltered xylano-pectinolytic enzymatic bleaching approach was investigated, for manufacturing wheat straw-based paper. The enzymatic step was found to be most effective, with xylanase-pectinase dose of 4-1.7 IU/g pulp and time period of 180 min. The absorption spectra of the pulp free filtrate samples obtained after treatment of the pulp with ultrafiltered enzymes showed the removal of more impurities, in comparison to the treatment with crude enzymes. Microscopic analysis also showed the removal of lignin impurities in enzymatically bleached pulp samples. This bleaching approach using enzymes resulted in 27% reduction in ClO2 dose. Ultrafiltered enzymes treated pulp samples also showed improved quality-related parameters, and Gurley porosity, burst index, breaking length, double fold, tear index, and viscosity increased by 19.05, 13.70, 8.18, 29.27, 4.41, and 13.27%, respectively. The lignin content, TDS, TSS, BOD and COD values also decreased in the effluent samples obtained after enzymatic bleaching plus 73% chemical bleaching dose. The BOD and COD values of the effluent samples improved by 23.01 and 23.66%, respectively. Thus, indicating the potential of ultrafiltered xylano-pectinolytic enzymes in reducing pollution during bleaching of wheat straw. This is the first study, mentioning the efficacy of ultrafiltered enzymes in the bleaching of wheat straw-based paper with better optical-strength-related properties and effluent characteristics.

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

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 250 IU of pectinase and xylanase, respectively, per gram of wheat straw, 180 min 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.

Production of eco-friendly and better-quality sugarcane bagasse paper using crude xylanase and pectinase biopulping strategy.

This research aimed to investigate the efficiency of crude xylanase-pectinase in pulping of sugarcane bagasse. Optimum biopulping was obtained, using xylanase-pectinase dose 200-60 IU/g, bagasse/liquid ratio 1:10 and 1.0% Tween 80 concentration at 55 °C temperature, pH 8.5 and period of treatment 180 min. Treatment of sugarcane bagasse samples with these enzymes generated pulp with lower rejections (58.76%), total solids (12.64%), kappa number (47.77%), higher screened pulp yield (10.66%), along with enhanced optical and physical properties, in comparison with a chemical pulp. Bagasse biopulping resulted in a 13% decrease in alkali dose to obtain the optical and physical properties similar to those achieved under the 100% alkali dose. The breaking length, burst factor, tear index, double fold, gurley porosity and viscosity were improved by 15.19, 37.64, 2.47, 37.77, 35 and 23.17%, respectively, after bleaching treatment of biopulped samples. Thus, enzymatic pulping is an eco-friendly environmentally sustainable approach, since it reduces the use of pulping chemicals and simultaneously improves the paper quality. This is the first report, showing pulping of sugarcane bagasse, with crude xylanase-pectinase, produced by an isolate.

An eco-friendly biocatalytic process for producing better quality paper from sugarcane bagasse using ultrafiltered enzymes concoction.

In the current study, pretreatment of sugarcane bagasse has been carried out with ultrafiltered xylano-pectinolytic enzymes, before conventional chemical bleaching process. Optimized enzymatic dose (4 IU xylanase and 1.2 IU pectinase per g of oven dried pulp) and retention time (180 min) were determined on the basis of maximum decrement in kappa number (from 20.93 to 15.32), release of maximum sugars (7.4 mg/g) as well as attainment of maximum brightness (25.1% ISO), whiteness (from - 57.3 to - 41.9) and minimum yellowness (from 48.7 to 35.3) of the pulp samples. Enzymatically treated samples also showed release of phenolic, lignin and hydrophobic compounds in their filtrates. Nearly 30% decrement in the exhaustion of bleaching chemical dose was detected as compared to control samples. The physical properties such as tear index, burst index, double fold number, breaking length, gurley porosity and viscosity of enzymo-chemically treated bagasse pulp samples were improved by 6.68%, 33.86%, 22.92%, 13.43%, 17.5% and 9.64%, respectively. Additionally, a decrement of 36.75% and 28.29% in the values of BOD and COD of the effluents was also noted, which demonstrated the fact that, inclusion of enzymes in chemical based protocols of paper and pulp industries could be a highly beneficial and eco-friendly approach in upcoming decades. This is the first report mentioning the effect of ultrafiltered xylano-pectinolytic enzymes concoction on sugarcane bagasse pulp.

Eco-friendly Bleaching of Agrowaste Wheat Straw Using Crude Alkalo-Thermotolerant Cellulase-Free Xylano-Pectinolytic Enzymes.

The aim of this study was to evaluate the potential of xylanase-pectinase enzymes in bleaching of wheat straw pulp, just to cut down the toxic wastes, in order to manage the environmental pollution. The appropriate parameters of bleaching were evaluated, and best conditions were xylanase and pectinase dose of 5.0 and 1.66 IU/g of pulp, respectively, along with material to liquid ratio of 1:7.5 (g/ml), temperature 55 °C, treatment time 3 h, Tween-80 1%, and pH 8.5. The release of reducing sugar and other non-cellulosic impurities, phenolic-hydrophobic-lignin was maximum at best bleaching conditions. Prebleaching of wheat straw pulp using these enzymes showed 14.75% decline in kappa number. Enzymatic bleaching plus 100% chemical bleaching also led to 27.90% reduction in yellowness. Using this methodology, the consumption of active chlorine was reduced up to 25%, along with an increase in burst index (7.98%), tear index (3.42%), breaking length (5.30%), viscosity (11.22%), gurley porosity (12.50%), and double-fold number (23.08%), which exhibits a remarkable enhancement in all the properties of pulp treated with enzymes. Microscopic images also confirm the effectiveness of enzymatic treatment in bleaching of wheat straw pulp. BOD and COD values of effluent also decreased by 20.74 and 17.87%, respectively. This research focussing on producing better grade paper using an eco-friendly approach would certainly benefit the paper and pulp industry. This is the first report, depicting bleaching capability of xylanase-pectinase enzymes for soda-anthraquinone pulp of wheat straw.