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SUMMARY: Poly(butylene adipate) (PBA) and poly(ethylene succinate) (PEgS) with a M -n of 2 000 were used as building blocks of poly(ester-urethane)s. Trimethylhexamethylene diisocyanate (TMDI), TMDI/2-methyl-1,5-pentanediamine (MPDA)/TMDI and 4,49-methylenediphenyl diisocyanate (MDI) were used to build diurethane units into the polymer with a final M -n of the order of 30 000. Oxygen consumption was measured during incubation of a pure strain of gram-positive non-sporulating bacteria isolated from an industrial compost for household refuse, in the presence of powder and films. The diurethane junction units and the diurethane model compounds are not assimilated on the time-scale of the present work. The relative biodegradability of PBA, PEgS and the various poly(ester-urethane)s has been assigned to the mobility of the polyester chain segments.

SUMMARY:This work has been performed using two pure strains of gram positive bacteria isolated from an industrial compost for household refuse and garden soil. These microorganisms have a stable phenotype, are easy to grow and were shown to be efficient degraders of various organic structures. It has been possible to get an insight both into fundamental mechanistic aspects of the degradation and into the fate of the studied derivatives in composts. Among others, measurement of oxygen consumption as a function of incubation time together with isolation and identification of degradation intermediates and residues has shown that short diester-amides derived from phenylalanine are assimilated without prior hydrolysis. Also the mineralization of typical polyesteramides are limited by the assimilation of the fragments resulting from the ester groups hydrolysis.

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