title: Anaerobic biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by Acetobacterium malicum strain HAAP-1 isolated from a methanogenic mixed culture.
abstract: In previous work, we studied the anaerobic biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by a methanogenic mixed culture that biodegrades RDX by using H2 as the sole electron donor. Strain HAAP-1 was isolated after enriching for the homoacetogens in a mineral medium containing RDX and an H2-CO2 (80:20) headspace. Strain HAAP-1 degraded 29.0 microM RDX in <14 days and formed 13.0 mM acetate when grown in a mineral medium with an H2-CO2 headspace. Methylenedinitramine was observed as a transient intermediate, indicating ring cleavage had occurred. In live cultures containing an N2-CO2 headspace, RDX was not degraded, and no acetate was formed. The 16S rRNA gene sequence for strain HAAP-1, consisting of 1485 base pairs, had a 99.2% and 99.1% sequence similarity to Acetobacterium malicum and A. wieringae, respectively. This is the first report of RDX degradation by a homoacetogen growing autotrophically and extends the number of genera known to carry out this transformation.
authors.affiliation: Engineer Research & Development Center, Army Corps of Engineers, Construction Engineering Research Laboratory, P.O. Box 9005, 2902 Newmark Drive, Champaign, IL 61821-9005, USA. Neal.R.Adrian@erdc.usace.army.mil
authors.forename: Neal R
authors.initials: NR
authors.lastname: Adrian
authors.forename: Clint M
authors.initials: CM
authors.lastname: Arnett
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D045855:Acetobacterium / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D000693:Anaerobiosis; D001426:Bacterial Proteins / Q000032:analysis; D001673:Biodegradation, Environmental; D018533:Biomass; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000737:chemistry / Q000302:isolation & purification; D005557:Formaldehyde / Q000378:metabolism; D020459:Genes, rRNA / Q000235:genetics; D006859:Hydrogen / Q000378:metabolism; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D014227:Triazines / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D014227:Triazines; D005557:Formaldehyde; D006859:Hydrogen; D019342:Acetic Acid; C009160:cyclonite