Comparative evaluation of laccase mediated oxidized and unoxidized lignin of sugarcane bagasse for the synthesis of lignin-based formaldehyde resin

Abstract

Pretreatment using dilute acid is one of the strategies employed in a lignocellulosic biorefinery. The current study deals with the isolation, characterization, and oxidation of lignin from the enzymatic residue of acid pre-treated sugarcane bagasse. The study also focused on evaluating the reactivity of Laccase mediated oxidized lignin with the non-oxidized one for the preparation of lignin-based formaldehyde (LF) resin. In the current study, 100 % phenolic lignin was utilized for the synthesis of LF resin. Three different approaches (Alkaline hydrolysis, mild acidolysis & organosolv) have been employed to evaluate the effect of isolation method on the physicochemical properties of lignin. The isolation method had a bearing on the properties of lignin and its reactivity towards formaldehyde for the synthesis of LF resin. Alkali and organosolv lignin were found as promising candidates for the preparation of LF resin. Oxidized lignin exhibited better reactivity than the non-oxidized one.