Characterization of an Extracellular Polyester Depolymerase of Cryptococcus Laurentii

Abstract

An understanding of the mechanisms by which synthetic polymers are degraded by biological systems would be of value in the design of both degradable and nondegradable polymers. Although much research has been carried out on the design of polymers for both characteristics, there has been relatively little work reported on the mechanism of degradation. A number of laboratories have reported on the range of polymers of varying molecular weights that are degradable by microorganisms (Kaplan et al. , 1979; Darby and Kaplan, 1968; Klausmeier, 1966; Fields and Rodriguez, 1975; Fields, et al. , 1974; Tokiwa, et al. , 1976). There have, in addition, been a number of other reports of degradation of polyesters by microorganisms and their enzymes, as well as by commercially available enzymes (Tokiwa and Suzuki, 1977, 1977a; Fukumura, 1966; Tabushi, et al. , 1975; Huang, et al. , 1979). Our laboratory has, for some time, been examining the microbial degradation of polycaprolactone (PCL). We have isolated a number of organisms capable of degrading PCL’s of varying molecular weights (Benedict et al. , 1983, 1983a), have examined the breakdown products, and proposed a mechanisms of depolymerization (Cook, et al. , 1981; Jarrett, et al. , 1984). We are now more carefully examining the enzyme systems involved in the process. This report describes the characteristics of a partially purified enzyme of C. laurentii.