Relating Carbon and Nitrogen Isotope Effects to Reaction Mechanisms during Aerobic or Anaerobic Degradation of RDX (Hexahydro-1,3,5-Trinitro-1,3,5-Triazine) by Pure Bacterial Cultures

• DOI: 10.1128/aem.00073-16
• Publication Date: 2016-03-26T01:25:16Z
• Authors: Mark E. Fuller; Linnea Heraty; Charles W. Condee; Simon Vainberg; Neil C. Sturchio; J. K. Böhlke; Paul B. Hatzinger
• Keywords: Degradation; Isotope Analysis; Isotopes of nitrogen

ABSTRACT Kinetic isotopic fractionation of carbon and nitrogen during RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) biodegradation was investigated with pure bacterial cultures under aerobic anaerobic conditions. Relatively large bulk enrichments in 15 N were observed via ring cleavage (ε = −12.7‰ ± 0.8‰) nitro reduction −9.9‰ 0.7‰), comparison to smaller effects denitration −2.4‰ 0.2‰). 13 C enrichment negligible −0.8‰ 0.5‰) but larger degradation −4.0‰ 0.8‰), modest variability among genera. Dual-isotope ε C/ε analyses indicated that the three pathways could be distinguished isotopically from each other abiotic mechanisms. Compared initial δ value +9‰, values NO 2 − released ranged −7‰ +2‰ −42‰ −24‰ biodegradation. Numerical reaction models isotope production much than, systematically related to, different bacteria. Apparent intrinsic N-NO consistent an pathway experiments more complex processes formation associated cleavage. These results indicate potential for analysis residual differentiation further efforts examine composition products (e.g., x ) environment are warranted. IMPORTANCE This work provides first systematic evaluation organic explosive by pathways. It also data on nitrite produced Both these lead better understanding fate help improve monitoring remediation technologies.