MOLECULAR DESIGN OF BIODEGRADABLE FUNCTIONAL POLYMERS .5. ENZYMATIC DEGRADATION OF POLYCARBOXYLATES CONTAINING VINYL ALCOHOL BLOCKS, AS BIODEGRADABLE SEGMENT

Poly(sodium carboxylate)s containing vinyl alcohol blocks were prepare d, and their microbial degradability and the poly(vinyl alcohol) (PVA) dehydrogenase activity as a function of vinyl alcohol block length in the polymer chain were analyzed. A clear relationship between the bio chemical oxygen demand (BOD) biodegradability using the activated slud ge and the relative activity of PVA dehydrogenase of a PVA-assimilatin g strain, Alcaligenes faecalis KK314, was observed. A vinyl alcohol bl ock length of about 7 monomer units corresponds to the minimum chain l ength of the vinyl alcohol block length which acts as a biodegradable segment in the poly[(disodium fumarate)-co-(vinyl alcohol)]. The enzym atic cleavability of polycarboxylates containing vinyl alcohol blocks was estimated using the cell-free extracts of a PVA-assimilating micro bial strain, A. faecalis KK314, as the PVA-cleaving enzyme source for both PVA dehydrogenase and hydrolase. The molecular weight of the poly carboxylates was reduced depending on the vinyl alcohol block length, and a similar molecular weight reduction tendency was observed with re spect to the BOD values and PVA dehydrogenase activities.