Symbiotic degradation of polyethylene glycol (PEG) 20,000-phthalate polyester by phthalate ester- and PEG 20,000-utilizing bacteria

A newly isolated polyethylene glycol (PEG) 6000-utilizing bacterium, N6, was further acclimated to PEG 10,000, 15,000, and 20,000 in turn and finally assimilated PEG 20,000. Ethylene glycol (EG), diEG and PEG 200-20,000-phthalate (ph) polyesters were assimilated by cocultures of ph ester-utilizing Comamonas acidovorans N2 and either the PEG 20,000-utilizing strain N6 or the known symbiotic mixed culture E-l (S. terrae and Rhizobium sp.). The growth of PEG-utilizing bacteria on PEG and that of the coculture of strains N2 and N6 on PEG-ph polyester were optimized. The polymer was either degraded by growing cells or washed cells of C. acidovorans N2 and strain N6. The degradation pattern for PEG was considered to be the same as proposed previously, i.e., exogenous depolymerization initialized by oxidation of two terminal alcohol groups.