The anaerobic biodegradation of the high explosive octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) by an extremely thermophilic anaerobe Caldicellulosiruptor owensensis, sp. nov

The aims of this research were to investigate the biological degradation of the high explosive octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) at thermophilic anaerobic conditions, and its kinetic characterization. An extremely thermophilic, non-spore forming rod that degraded HMX under strictly anaerobic conditions was isolated from a xylanolytic enrichment culture obtained from an uncontaminated water sediment. A pure culture of the isolate optimally degraded HMX at ;The isolate was identified as a new species of an extremely thermophilic anaerobic bacterium by biochemical tests, volatile fatty acid profile, moles percent of guanine plus cytosine (mol% G+C), and 16S rRNA gene sequence analysis. Phylogenetic analysis indicated that the isolate was a member of the Caldicellulosiruptor cluster. The isolate was named Caldicellulosiruptor owensensis. The effect of culture conditions, such as temperature, pH, and nutrients on growth of the isolate and HMX degradation was studied. The isolate degraded HMX through a cometabolic pathway, utilizing various saccharides as substrate for growth, the optimal one being xylose.;A uniformly radiolabeled HMX (UL-...