Hydrolase-catalyzed synthesis of polyamides and polyester amides

Developments in enzymatic polymerization have been ongoing for decades. Various studies on the enzymatic synthesis of polyesters, polycarbonates, polysaccharides, polypeptides, and polyamides have been performed and some of them have been implemented on industrial scale. Lipases are the most used catalyst in the synthesis of polyesters and polyamides. Extensive studies on the kinetics and the mechanism of lipase-catalyzed synthesis of polyesters have been carried out already, but the enzymatic synthesis of polyamides has received less attention. Therefore, the current research aims to address this by focusing more on the enzymatic synthesis of polyamides in order to get a better understanding of its reaction mechanism.

Polyamides are widely used polymers in daily and industrial applications, due to their high mechanical strength and good thermal resistance. Synthesis of most polyamides involves the use of aggressive chemicals and high temperatures. Bio-catalytic approaches might be superior alternative synthesis routes, which can be performed under mild reaction conditions. In this research, the synthesis of aliphatic oligoamides (nylon-4,10, nylon-6,10, and nylon-8,10), aliphatic-aromatic oligoamides, and poly(ε-CL-co-β-lactam) was performed. These reactions were catalyzed by immobilized Fusarium solani pisi cutinase or Candida antarctica lipase B (CAL-B). Immobilized Fusarium solani pisi cutinase was prepared by two different methods: (1) physical adsorption on Lewatit (polymethyl methacrylate) beads and (2) cross-linked enzyme aggregates (CLEA).