Bio-degradation assays were performed for bio-based polymers under environmental conditions with controlled temperature and pH using pH Stat titration. Suspensions of PLA and PBS microparticles, produced by e.g. cryo-milling, were incubated with proteolytic and lipolytic enzymes. Rates of hydrolysis, as determined by counter-titration with a diluted base (NaOH), was recorded for two hours. The thermal profile of PLA hydrolysis by protease was investigated. All measurements were conducted under controlled laboratory conditions.

The columns headings are abbreviated and mean the following. Min: Duration of the titration in minutes; ml: Volume of added NaOH. Unless otherwise specified, c (NaOH) = 10 mM; pH: pH value of the suspension, set to 8.2; °C: Temperature of the suspension.