A Highly Efficient Ferulic Acid Decarboxylase from Capronia coronata: Characterization and Biocatalytic Applications

Ferulic acid decarboxylases (FDCs) are versatile biocatalysts that catalyze reversible (de)carboxylation of unsaturated aromatic and aliphatic compounds, holding significant potential for applications in biocatalytic decarboxylation reactions and in CO2 conversion into chemicals. In this study, we characterized the FDC from Capronia coronata (CcFDC) with a focus on its activity, kinetic properties, substrate specificity, and carboxylation potential. The enzyme exhibited a high turnover frequency (TOF) of 1857 min⁻¹ and a total turnover number (TTN) of 110,013 for trans-cinnamic acid, suggesting strong productivity for decarboxylation to yield biostyrene. Substrate profiling revealed a broad substrate scope, with CcFDC demonstrating activity toward several cinnamic acid derivatives and lignin-derived compounds. Molecular docking studies supported these findings by identifying key structural features that influence substrate binding and activity. Importantly, CcFDC was shown to facilitate the carboxylation of styrene and furoic acids under mild conditions using bicarbonate as a carbon source, leading to detectable amounts of carboxylation products, suggesting a potential biocatalyst to mediate conversion of CO2 into commodity chemicals.