Enzymatic polymerization for precision polymer synthesis

Our recent advances in enzymatic polymerization, defined as chemical polymer syntheses in vitro (in test tubes) via non-biosynthetic pathways catalyzed by an isolated enzyme, have been mainly reviewed. The major target macromolecules formed via the enzymatic polymerizations described in this article are polysaccharides, polyesters, and polyaromatics. For synthesis of polysaccharides and polyesters, hydrolases are used as catalysts; hydrolases catalyzing a bond-cleavage reaction by water induce the reverse reaction of hydrolysis, leading to polymer production by a bond-forming reaction in vitro. Specific enzyme catalysis provides a novel synthetic route with precise structure control not only for natural biopolymers such as cellulose, xylan, and chitin, but also for unnatural polysaccharides and polyesters, many of which are difficult to be synthesized by conventional methodologies. Oxidoreductases act as catalysts for oxidative polymerization of phenol, aniline, and their derivatives. A new class of phenolic polymers are synthesized without use of toxic formaldehyde under mild reaction conditions. Enzyme-model complexes also catalyze polymerizations for the synthesis of new high-performance polymeric materials.