Isolation and characterization of an ether-type polyurethane-degrading micro-organism and analysis of degradation mechanism by Alternaria sp.
OBJECTIVE
To degrade ether-type polyurethane (ether-PUR), ether-PUR-degrading micro-organism was isolated. Moreover, ether-PUR-degrading mechanisms were analysed using model compounds of ether-PUR.


RESULTS
A fungus designated as strain PURDK2, capable of changing the configuration of ether-PUR, has been isolated. This isolated fungus was identified as Alternaria sp. Using a scanning electron microscope, the grid structure of ether-PUR was shown to be melted and disrupted by the fungus. The degradation of ether-PUR by the fungus was analysed, and the ether-PUR was degraded by the fungus by about 27.5%. To analyse the urethane-bond degradation by the fungus, a degraded product of ethylphenylcarbamate was analysed using GC/MS. Aniline and ethanol were detected by degradation with the supernatant, indicating that the fungus secreted urethane-bond-degrading enzyme(s). PURDK2 also degraded urea bonds when diphenylmethane-4,4'-dibutylurea was used as a substrate.


CONCLUSIONS
The enzyme(s) from PURDK2 degraded urethane and urea bonds to convert the high molecular weight structure of ether-PUR to small molecules; and then the fungus seems to use the small molecules as an energy source.


CONCLUSIONS
Ether-PUR-degrading fungus, strain PURDK2, was isolated, and the urethane- and urea-bonds-degrading enzymes from strain PURDK2 could contribute to the material recycling of ether-PUR.
Matsumiya
Y
Y
Department of Bioscience and Technology, College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, Japan.
Murata
N
N
Tanabe
E
E
Kubota
K
K
Kubo
M
M
D000528:Alternaria / Q000145:classification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D004271:DNA, Fungal / Q000235:genetics; D004987:Ethers / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D048448:Phenylcarbamates / Q000378:metabolism; D011140:Polyurethanes / Q000378:metabolism*; D014508:Urea / Q000031:analogs & derivatives / Q000378:metabolism
D004271:DNA, Fungal; D004987:Ethers; D048448:Phenylcarbamates; D011140:Polyurethanes; D014508:Urea