Alkali-based lignin extraction from lignocellulosic material and upgradation of residual pulp as bio-packaging material towards sustainable biomass utilization

The current study explored the extraction of lignin from paddy straw and kans grass, while focusing on the yield and physico-chemical properties of lignin. Alkali-based lignin extraction from lignocellulosic biomass indicated a positive correlation between NaOH concentration and lignin yield. An increase in NaOH concentration from 0.50 % to 2.00 % resulted in increased yield of lignin from 129.16 to 447.07 mg/g and 222.79 to 551.37 mg/g of lignin from paddy straw and kans grass, respectively. The extracted lignin was characterized by FTIR and XRD, showed its chemical structure homogeneity with commercial lignin. Bio-packaging specimens were created using residual pulp and characterized for their physical and mechanical properties. The specimens of both the biomass were found to effectively withstand a load of 7.36 kg and 11.17 kg, respectively before crumpling. Further, the mass balance of the optimized process showed its industrial applicability for the fractionation and utilization of lignocellulosic biomass. [Display omitted] •Alkali-based lignin extraction process was optimized for paddy straw and kans grass.•Lignin yield of 0.42 g/g and 0.49 g/g was obtained from paddy straw and kans grass.•FTIR and XRD study showed structural similarities between extracted and soda lignin.•The residual pulp after lignin extraction was suitable for bio-packing material.