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

Recycling of printed Xerographic paper using Aspergillus assiutensis enzyme cocktail: an integrated approach to sustainable development

To overcome the human and animal survivability risk, sustainable development is the only option on earth that can be achieved through the maximum use of renewable environmental resources. Recycling of waste paper is an emerging waste management approach to conserve natural resources. Herein, we studied enzyme-mediated process to recycle the xerographic paper by using the crude fungal extract from indigenously isolated fungi identified as Aspergillus assiutensis. The fungal enzyme cocktail has been characterized for the production of multiple enzymes namely cellulase, amylase, xylanase, pectinase, and protease. All these enzymes have pH optima in the acidic range and except cellulase and all the enzymes are stable from 10 to 80 C. In the zymogram analysis, pectinase, xylanase, amylase, and cellulase were detected at 68 kDa, ~ 54 kDa, 38 kDa, and 30 kDa, respectively. Also, the presence of protease was confirmed by the clear zone at 68, 31, and 16 kDa. A 26% decrease in the kappa number and reduction in Hex A of the pulp was observed on the treatment of the pulp with enzyme as compared to the control pulp without any treatment. The physical and chemical properties of the pulp were also improved by enzyme-mediated pulping as compared to the control The physiochemical parameter of the effluent like TDS was reduced (397 ppm) significantly in comparison to chemical deinking process and it was within the permissible limit. BOD and alkalinity were reduced when the enzymes and chemical dosage were used in combination. These results indicate that chemi-enzymatic deinking is most promising to reduce or remove the pollution parameters including ink and this approach can be used in the paper and pulp industry for sustainable development.

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.