Transforming lignin into biocompatible aliphatic acids via oxidative dearomatization using a polyoxometalate catalyst

Oxidative chemical catalysis holds the promise of derivatizing lignin into bioavailable organic molecules that can act as supplementary carbon sources in fermentation processes. Here, we demonstrate the oxidative valorization of technical lignin, biorefinery lignin, and raw lignocellulosic biomass using a cholinium phosphotungstate catalyst. The resulting product stream consists predominantly of low-molecular-weight aliphatic acids, including formic, acetic, and oxalic acids, achieving high overall conversion of the starting biopolymers. Under optimized conditions, up to ∼500 and ∼1,250 mg of carboxylic acids were produced per gram of biorefinery lignin and raw biomass, respectively. The oxidized streams were evaluated for microbial bioavailability, and multiple microorganisms exhibited robust growth. These results establish a viable pathway for converting lignin and crude lignocellulose into bioavailable products by leveraging phosphotungstate-mediated oxidation, enabling the valorization of previously underutilized carbon fractions in biorefinery processes.