CHEMICAL AND PHYSICAL CHANGES OCCURRING IN POLYESTER POLYURETHANE DURING BIODEGRADATION

An account of the biodegradation of polyester polyurethane by a bacterium, tentatively identified as a species of Corynebacterium, is presented. This isolate reduced both the tensile strength and percentage elongation at break of the test material within three days of inoculation, in a mineral salts medium supplemented with yeast extract. FTIR studies showed that the degradation observed was due to the hydrolysis of the ester linkages. Degradation was not recorded, for any of these parameters, where the inoculated test material was incubated in the presence of a mineral-salts medium supplemented with glucose or in sterile controls. Extracellular esterase activity was detected in cell-free supernatants where the mineral-salts medium was supplemented with yeast extract. However, the addition of the test material did not enhance esterase activity or the viable cell number. It is considered that the test material was not being utilised for nutritional purposes and was degraded as a result of co-metabolism.