Phenolic Compounds Derived from Plant Metabolism and Lignin: Biotransformation and Technological Applications

Abstract In the context of increasing energy scarcity and the environmental impact of conventional energy pathways, alternative sources are under active investigation. Plants serve as excellent models for understanding adaptive metabolic mechanisms, producing bioactive aromatic compounds (AC) and phenolic compounds (PC). These secondary metabolites, which are also integral components of lignin, are crucial for plant survival in the face of climate change and as potential new products, including petrochemical substitutes. Thus, primary and secondary plant metabolites, along with the non-glycosidic lignin fraction composed of AC and PC, constitute valuable substrates for synthesizing novel materials, polymers, and phenolic derivatives via chemical or biological transformations. Phenolic compounds such as ferulic, p -coumaric, and caffeic acids, as well as vanillin (VN) together with the related metabolite shikimic acid, have direct applications in the pharmaceutical, cosmetic, and food-additive industries. These compounds also serve as substrates for microorganisms and their enzymes in bioprocesses aimed at producing higher-value products. This review addresses the chemical and biotransformation of these compounds by microorganisms and enzymes, highlighting their potential as substitutes for fine chemicals derived from petroleum. Graphical abstract