Characterization of metabolites during biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) with municipal anaerobic sludge

The biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in liqu id cultures with municipal anaerobic sludge showed that at least two degrad ation routes were involved in the disappearance of the cyclic nitramine. In one route, RDX was reduced to give the familiar nitroso derivatives hexahy dro-1-nitroso-3,5dinitro-1,3,5-triazine (MNX) and hexahydro-1,3-dinitroso-5 -nitro-1,3,5-triazine (DNX), In the second route, two novel metabolites, me thylenedinitramine [(O2NNH)(2)CH2] and bis(hydroxymethyl)nitramine [(HOCH2) (2) NNO2], formed and were presumed to be ring cleavage products produced b y enzymatic hydrolysis of the inner C-N bonds of RDX, None of the above met abolites accumulated in the system, and they disappeared to produce nitrous oxide (N2O) as a nitrogen-containing end product and formaldehyde (HCHO), methanol (MeOH), and formic acid (HCOOH) that in turn disappeared to produc e CH4 and CO2 as carbon-containing end products.