Production of Valuable Phenolic Compounds from Lignin by Biocatalysis: State-of-the-Art Perspective

Lignin, a major component of lignocellulose, is the only type of biomass that can provide aromatic monomers. Although lignin is abundant and found in quantities scalable for industrial processes, its role as an industrial feedstock is currently underutilized. This review summarizes the current technology used for the process of lignin deconstruction. Phenolic derivatives obtained from lignin deconstruction can be further transformed by various enzymatic reactions to increase their application value. Esterification and glycosylation are methods through which the hydrophobicity and hydrophilicity of phenolic compounds can be increased, respectively. Substituents on the aromatic ring of phenolic compounds can be modified by hydroxylation/monooxygenation, methylation, demethylation, and decarboxylation/carboxylation to adjust their function to fit various types of applications. The concepts and methods presented herein are green and sustainable technology that can convert low value biomass into value-added chemicals.