Whole community transcriptome of a sequencing batch reactor transforming 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one (NTO)

Abstract

Two sequencing batch reactors (SBRs) were run to bio-mineralize 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one (NTO) in lab scale settings. The reactors were shown to reproducibly biotransform these munitions under aerobic and anaerobic conditions during the operations of these SBRs. Complete removal (100% biotransformation) of DNAN (initially 17.7 ± 5.4 mg L) and NTO (initially 15.0 ± 7.1 mg L) was observed in an anaerobic SBR when Luria-Bertani (LB) broth was present. In contrast, an aerobic SBR degraded only 58 ± 22% of DNAN (initially 19.7 ± 6.2 mg L) and 45 ± 24% of NTO (initially 9.7 ± 6.3 mg L) when either LB or glucose was also added indicating that anaerobic conditions are more favorable for biotransformation of these munitions. Transcriptomic analysis of the DNAN and NTO degrading anaerobic SBR revealed upregulation of a putative nitroreductase, hydroxylaminophenol mutases, 4-hydroxylphenyl acetate associated genes, and quinone oxioreductases. Major Bacterial populations included Bacteroidales, Campylobacterales, Enterobacteriales, Pseudomonadales, Burkholderiales and Clostridiales. Results from this study can be used to inform investigation of munition degrading organisms and the functional genes responsible.

A review of treatment methods for insensitive high explosive contaminated wastewater

“…Bioreactors have been used to successfully degrade DNAN and NTO in synthetic wastewater with aerobic removal efficiencies of 58 ± 22% and 45 ± 24%, respectively when using purely aerobic methods ( Weidhaas et al., 2018 ). In addition, specific strains of microbial organism have been identified that are able to degrade DNAN completely despite the presence of other IHE ( Karthikeyan and Spain, 2016 ).…”

“…There have also been reports of DNAN, NTO and nitroguanadine (NQ) being degraded from mixed solution ( Richard and Weidhaas, 2014 ). Biodegradation systems that use multiple, sequenced reactors have shown more promise in removing IHE from wastewater with removal rates of up to 100% when using aerobic/anaerobic sequences ( Weidhaas et al., 2018 ). Alternative methods for increasing the removal efficiency of IHE from wastewater include the use of electron donors such as sodium pyruvate which was shown to increase the removal rate of NTO from solution in waster to 93.5% in an anaerobic-aerobic system ( Madeira et al., 2017 ).…”

“…Suitability limited to larger facilities 14 (Weidhaas et al, 2018) 15 (Madeira et al, 2017) 16 (Platten et al, 2010(Platten et al, , 2013 17 (Karthikeyan and Spain, 2016) Kapoor, 2001), RDX (Morley and Fatemi, 2010) and DNAN (Boddu et al, 2009). When a carbon filter has been totally saturated with contaminant and can no longer adsorb any more material it is not completely spent.…”

Right on target: using plants and microbes to remediate explosives

“…Toward the identification of microbial genes responsible for DNAN detoxification, transcriptome analysis on microbial populations fed DNAN and NTO reported the upregulation of nitroreductase, hydroxylaminophenol mutase, 4-hydroxylphenyl acetate-associated genes, and quinone oxidoreductases (Weidhaas et al 2018).…”

“…To profile the communities involved in NTO biodegradation, a metagenomic approach used enrichment cultures supplemented with molasses, methanol, or thiosulfate and identified predominately Pseudomonadaceae, Clostridiaceae and Sporolactobacillaceae (Eberly et al 2016). The subsequent, whole community, transcriptome profiling on batch reactors dosed with NTO and DNAN revealed the upregulation of many genes implicated in the classic detoxification of xenobiotics (Weidhaas et al 2018). Among these was N-ethylmaleimide reductase, a member of the OYE family; other OYE homologs are able to transform nitrate ester and nitroaromatic explosives (Williams et al 2004).…”