Laccase-mediated oxidation of small organics: bifunctional roles for versatile applications

• The diverse laccase-catalyzed oxidation reactions with small organics are classified into two types: catabolic and anabolic.
• These bifunctional actions are readily found in laccase-driven in vivo metabolic pathways.
• Biological functions of the in vivo metabolisms can inspire discovery of new application areas for in vitro bifunctional reactions of laccases and small organics.

Laccases have been widely used in several biotechnological areas, including organic synthesis, bioremediation, and pulp/textile bleaching. In most applications, the enzymatic actions start with single-electron oxidation of small organics followed by formation of the corresponding radicals. These radicals are subsequently involved in either oxidative coupling (i.e., bond formation) or bond cleavage of target organics. These bifunctional actions – catabolic versus anabolic – are readily identifiable in in vivo metabolic processes involving laccases. Here, we characterize the bifunctionality of laccase-mediated oxidation of small organics and present the view that knowledge of the biological functions of these metabolic processes in vivo can illuminate potential biotechnological applications of this bifunctionality.