Microbial degradation of poly(aspartic acid) by two isolated strains of Pedobacter sp. and Sphingomonas sp.
Microbial degradation of thermally synthesized poly(aspartic acid) (PAA) was investigated. A PAA-P1 sample (Mn, 7500; Mw, 20,000; number of branched units/100 monomer units, 3.1) was completely degraded in natural river water within 15 days at 25 degrees C. A new PAA-degrading bacterium (strain KP-2: JCM10638) was isolated together with Sphingomonas sp. KT-1 (JCM10459) from river water, and identified as a member of Pedobacter. A Pedobacter isolate was capable of degrading high-molecular-weight PAA polymers of 5000 to 150,000, and a small amount of low-molecular-weight products of 250 to 5000 was accumulated as residues during the growth of the isolate on PAA. In contrast, the other isolate Sphingomonas sp. KT-1 degraded only low-molecular-weight PAA below 5000. A mixed culturing of Pedobacter sp. KP-2 with Sphingomonas sp. KT-1 resulted in a complete degradation of PAA-P1 sample, but a small amount of low molecular weight components was accumulated during the degradation of highly branched PAA-P2 and PAA-P3 samples.
Tabata
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Polymer Chemistry Laboratory, RIKEN Institute, Hirosawa, Wako-shi, Saitama 351-0198, Japan.
Abe
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Doi
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D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D005618:Fresh Water; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D010455:Peptides / Q000378:metabolism*; D020578:Sphingomonas / Q000378:metabolism*; D014871:Water Microbiology
D010455:Peptides; C017645:polyaspartate