The enzymatic degradation and polymerization using an enzyme were carried out with respect to the establishment of a sustainable chemical recycling system for poly(epsilon -caprolactone) (PCL) which is a typical biodegradable synthetic plastic. The enzymatic transformation of PCL having an M-n of 110 000 using Candida antarctica lipase (lipase CA) in water-containing toluene at 40 degreesC afforded the corresponding cyclic dicaprolactone (DCL, 1,8-dioxacyclotetradecane-2,9-dione) in a yield of up to 97%. Thus the obtained DCL readily polymerized again using both the fresh and recovered lipase CAs.