Elucidating the mechanisms associated with the anaerobic biotransformation of the emerging contaminant nitroguanidine

Erika E. Rios-Valenciana, Osmar Menezes, Jonathan Romero, Corey Blubaum, Mark J. Krzmarzick, Reyes Sierra-Alvarez, Jim A. Field

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Nitroguanidine (NQ) is a constituent of gas generators for automobile airbags, smokeless pyrotechnics, insecticides, propellants, and new insensitive munitions formulations applied by the military. During its manufacture and use, NQ can easily spread in soils, ground, and surface waters due to its high aqueous solubility. Very little is known about the microbial biotransformation of NQ. This study aimed to elucidate important mechanisms operating during NQ anaerobic biotransformation. To achieve this goal, we developed an anaerobic enrichment culture able to reduce NQ to nitrosoguanidine (NsoQ), which was further abiotically transformed to cyanamide. Effective electron donors for NQ biotransformation were lactate and, to a lesser extent, pyruvate. The results demonstrate that the enrichment process selected a sulfate-reducing culture that utilized lactate as its electron donor and sulfate as its electron acceptor while competing with NQ as an electron sink. A unique property of the culture was its requirement for exogenous nitrogen (e.g., from yeast extract or NH4Cl) for NQ biotransformation since NQ itself did not serve as a nitrogen source. The main phylogenetic groups associated with the NQ-reducing culture were sulfate-reducing and fermentative bacteria, namely Cupidesulfovibrio oxamicus (63.1% relative abundance), Dendrosporobacter spp. (12.0%), and Raoultibacter massiliens (10.9%). The molecular ecology results corresponded to measurable physiological properties of the most abundant members. The results establish the conditions for NQ anaerobic biotransformation and the microbial community associated with the process, improving our present comprehension of NQ environmental fate and assisting the development of NQ remediation strategies.

Original languageEnglish (US)
Article number119496
JournalWater research
Volume229
DOIs
StatePublished - Feb 1 2023

Keywords

  • Bioremediation
  • Insensitive munitions compounds
  • Lactate
  • Nitrosoguanidine
  • Propellant
  • Sulfate-reduction

ASJC Scopus subject areas

  • Environmental Engineering
  • Civil and Structural Engineering
  • Ecological Modeling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

Fingerprint

Dive into the research topics of 'Elucidating the mechanisms associated with the anaerobic biotransformation of the emerging contaminant nitroguanidine'. Together they form a unique fingerprint.

Cite this