Polylactide Degradation in the Presence of Members of the Genus Bacillus

— Microorganisms of the genus Bacillus were shown to have different effects on the degradation of polylactide packaging material. The degradation experiment was carried out on an agar medium at a temperature of 55°C and pH 5.9 for 14 days. This is the first report on the abiotic hydrolysis significantly slowing down during incubation with B. licheniformis S8 and occurring in parallel with the main process, enzymatic hydrolysis. The latter involved sequential cleavage of monomer units from the end of the macromolecule and the formation of low molecular weight products used by microorganisms as a substrate; it contributed to a decrease in the mass of polylactide by 5.1%, while maintaining its molecular weight and decreasing the molecular-weight dispersity. In the presence of bacteria B. amyloliquefaciens , B. subtilis subsp. spizizenii , and B. subtilis subsp. inaquosorum , the mass of polymer sample did not decrease, but the molecular weight decreased significantly, similar to abiotic hydrolysis.