Degradation of CL-20 by white-rot fungi.
In previous studies, we found that the emerging energetic chemical, CL-20 (C6H6N12O12, 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane), can be degraded following its initial denitration using both aerobic and anaerobic bacteria. The C and N mass balances were not determined due to the absence of labeled starting compounds. The present study describes the degradation of the emerging contaminant by Phanerochaete chrysosporium using ring-labeled [15N]-CL-20 and [14C]-CL-20. Ligninolytic cultures degraded CL-20 with the release of nitrous oxide (N2O) in amounts corresponding to 45% of the nitrogen content of CL-20. When ring-labeled [15N]-CL-20 was used, both 14N14NO and 15N14NO were observed, likely produced from -NO2 and N-NO2, respectively. The incubation of uniformly labeled [14C]-CL-20 with fungi led to the production of 14CO2 (> 80%). Another ligninolytic fungus, Irpex lacteus, was also able to degrade CL-20, but as for P. chrysosporium, no early intermediates were observed. When CL-20 was incubated with manganese peroxidase (MnP), we detected an intermediate with a [M-H]- mass ion at 345 Da (or 351 and 349 Da when using ring-labeled and nitro-labeled [15N]-CL-20, respectively) matching a molecular formula of C6H6N10O8. The intermediate was thus tentatively identified as a doubly denitrated CL-20 product. The concomitant release of nitrite ions (NO2-) with CL-20 degradation by MnP also supported the occurrence of an initial denitration prior to cleavage and decomposition.
Fournier
Diane
D
Biotechnology Research Institute, National Research Council of Canada, Environmental Chemistry Group, 6100 Royalmount Avenue, Montreal, Que., Canada H4P 2R2.
Monteil-Rivera
Fanny
F
Halasz
Annamaria
A
Bhatt
Manish
M
Hawari
Jalal
J
D000814:Aniline Compounds / Q000378:metabolism; D001372:Aza Compounds / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002250:Carbon Radioisotopes / Q000737:chemistry; D002412:Cations; D008401:Gas Chromatography-Mass Spectrometry; D006571:Heterocyclic Compounds / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism; D009578:Nitrobenzenes / Q000378:metabolism; D009609:Nitrous Oxide / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D020075:Phanerochaete / Q000378:metabolism*; D012989:Soil Pollutants / Q000378:metabolism*; D013997:Time Factors
C482139:2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaaza-isowurtzitane; D000814:Aniline Compounds; D001372:Aza Compounds; D002250:Carbon Radioisotopes; D002412:Cations; D006571:Heterocyclic Compounds; D009573:Nitrites; D009578:Nitrobenzenes; D012989:Soil Pollutants; D010544:Peroxidases; C051129:manganese peroxidase; C015384:nitramine; D009609:Nitrous Oxide