Self-regulating degradation technology for the biodegradation of poly(lactic acid)

The enzymatic degradation of aliphatic polyesters is often hindered by the decrease of pH with time. The phenomenon is caused by the formation of the monomer and other oligomers in the aqueous medium, which are weak acids and partially dissociate. The effect is especially pronounced during the degradation of poly(lactic acid) (PLA). Although lactic acid is a weak acid, its formation and dissociation can drastically reduce the pH and denature the enzyme. An approach is proposed in this work in which the degradation medium controls its own pH and keeps it neutral. The technology assures that manual work or expensive feedback-controlled instrumentation are not required during degradation. The concept of the self-regulating degradation technology relies on parallel solubility and acid–base equilibria. The material creating the equilibria and leading to self-regulation is calcium carbonate, which is cheap and available in large quantities. Accordingly, the technology developed can be scaled up to industrial volumes. Moreover, computational tools have been developed that facilitate the analysis and close control of enzyme-catalyzed degradation of aliphatic polyesters in self-regulating media.