Studies on enzymatic hydrolysis of synthetic aliphatic copolyesters

The rates of enzymatic hydrolysis of polyesters are in general influenced by a wide variety of parameters including molar mass, segmental mobility, chemical and stereochemical structure, surface area, morphology and crystallinity. In this study a series of high molar mass poly(butylenesuccinate-co-butylenesebacate)s, P(BS-co-BSe)s, were synthesized by melt polycondensation from 1,4-butanediol and dimethylesters of succinic and sebacic acids. Filmed samples were assayed to enzymatic degradation by lipase from Mucor miehei or Lipase from Rhizopus arrhizus and the relative normalised weight loss rates were compared. Changes in the degree of crystallinity show negligible effect on polyesters enzymatic degradation. The rate-determining factor of the enzymatic hydrolysis appears to be closely related to the polymer chain structure that strongly influences the activity of both lipases in P(BS-co-BSe) copolymers. High Performance Liquid Chromatography - Mass Spectrometry (HPLC-MS) was used to identify the oligomers, in which the copolyesters were hydrolyzed. Preliminary results point out the selectivity of the Lipases used, related to the chemical structure of the copolyesters synthesized.