Hexahydro-1,3,5-Trinitro-1,3,5-Triazine (RDX) Serves as a Carbon and Energy Source for a Mixed Culture Under Anaerobic Conditions

Abstract

We studied the anaerobic biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in a mineral medium by a mixed culture. RDX degradation activity was maintained for more than a year with only the addition of RDX. We observed a steady increase in the protein concentration of the culture from 4.8 microg mL(-1) to more than 24.4 microg mL(-1), a >400% increase. There was only a slight increase in protein in the RDX unamended control bottles containing live culture, increasing from 4.8 microg mL(-1) to 7.8 microg mL(-1). Radiolabeled (14)C-RDX confirmed mineralization of the cyclic nitramine to (14)CO(2). After 164 days, 35% of the radiolabel was recovered as 14CO2. This is the first report demonstrating the mineralization of RDX when it serves as a growth substrate for a mixed culture.