Novel approach: Lignin extraction from sequentially pretreated sugarcane trashes to produce prospective nanolignin/PVA biosurfactants

A sustainable and eco-friendly approach for utilizing sugarcane trash (SCT) biomass is currently under development. The SCT was subjected to a sequential pretreatment process involving microwave irradiation and autoclave heating before extracting alkali lignin. Nanolignin was then synthesized from the extracted lignin. The particle size of the synthesized nanolignin ranged between 65 and 84 nm, according to morphological characterization. This nanolignin was then transformed into a nanolignin/polyvinyl alcohol (PVA) biosurfactant via an eco-friendly solvent. The surface tension and functional groups of the biosurfactant were evaluated. The yield of lignin obtained from SCT varied between 25 % and 28 %, with the same purity of 70 %. The physical, chemical, and morphological characteristics of isolated lignin are comparable, making it possible to produce nanolignin for biosurfactant synthesis. The presence of aryl–O stretching (1200 cm⁻¹) and 1,4–disubstituted CH bending (800 cm⁻¹) peaks of absorbance in the infrared spectra indicated that the grafting of nanolignin into PVA occurred in the phenolic group of lignin. The biosurfactant nanolignin from autoclave treatment has a low surface tension of 42.20 mN/m, making it a more environmentally friendly additive in lignocellulose hydrolysis.