THE BIODEGRADATION OF LOW-MOLECULAR-WEIGHT URETHANE COMPOUNDS BY A STRAIN OF EXOPHIALA-JEANSELMEI

To further analyze the biodegradation of polyurethane polymers, we inv estigated the biodegradation of low-molecular-weight N-tolylcarbamate model compounds with structures closely resembling the urethane linkag es found in polyurethanes based on tolylene-diisocyanate (TDI), Soil m icroflora were screened for microorganisms that were able to utilize t oluene-2,4-dicarbamic acid, diethyl ester (compound 1) as the sole sou rce of carbon, and the soil fungus Exophiala jeanselmei strain REN-11A was selected as the most effective strain, Several N-tolylcarbamate c ompounds were used, and it was found that REN-11A was able to degrade compound 1, as well as the related compound toluene-2,6-dicarbamic aci d, diethyl ester, very efficiently, Further investigation showed that compound 1 was biodegraded to tolylene-2,4-diamine via the aromatic am ine intermediates carbamic acid, (3-amino-4-methylphenyl)-, ethyl este r and carbamic acid, (5-amino-2-methylphenyl)-, ethyl ester.