Aspergillus oryzae lipase-mediated in vitro enzymatic degradation of poly (2,2′-dimethyltrimethylene carbonate-co-ε-caprolactone)

Abstract

The amino acid sequence and spatial structure of lipases from different sources often result in significant differences in the active sites, which exhibit differential activity when interacting with a particular polymer, as reflected in the rate of degradation of the polymer. The research of the degradation properties of enzymes for specific polymers can therefore be a helpful guide in production. In this study, a series of copolymer poly(2,2′-dimethyltrimethylene carbonate-co-ε-caprolactone) P(DTC-co-CL) was prepared and the in vitro enzymatic degradation behavior of the resultant copolymers was performed in the lipase solutions (from Aspergillus oryzae, ≥100,000 U/g), and the effect of the CL content in composition on the degradation behavior of P(DTC-co-CL) was investigated. The results showed that lipase significantly can accelerate the degradation rate of P(DTC-co-CL), and the mass loss of P(DTC-co-CL) strongly depended on the CL content due to the prior cleavage of ester bonds under the catalysis activity of lipase enzymes. For the copolymers containing 85 mol% CL, 37.9% of mass loss and 75.2% remaining CL content were observed after degradation of 15 days. Samples with 75 mol% DTC content can maintain good dimensional stability after the degradation, indicating that the introduction of DTC was beneficial to maintain the morphology. The results showed that P(DTC-co-CL) had adjustable degradation properties and well form-stability, which was a promising candidate for biomedical applications.