THE BIODEGRADATION OF POLYMERS - RECENT RESULTS

After a general introduction including definition of biodegradability, the recent literature is briefly summarized. The results obtained in our laboratory for various polymers in three different composting units are then presented. They demonstrate that there is an urgent need for a quantitative method to characterize polymer biodegradation. For that purpose, a manometric method which allows the measurement of the oxygen consumed by the growing microorganisms has been developed. It has been tested with various inocula of increasing complexity: one Streptomyces sp., a mixture of three Streptomyces (badius, setonii and viridosporus), a compost extract or sewer sludge, growing in the presence of low molecular weight molecules as sole carbon source. Its performances and limitations are discussed. It is then applied to various polymer systems: polyesters and their constituent units, autoxidized polyethylene (APE) and its model compounds, polyvinyl alcohol (PVAl), starch and cellulose. The biodegradability of these polymers is characterized and their potential use as biodegradable materials for packaging, sanitary and agricultural uses is discussed.