TNT transformation products are affected by the growth conditions of Raoultella terrigena

Abstract

High concentrations of 2,4,6-trinitrotoluene (TNT) and related nitroaromatic compounds are commonly found in soil and groundwater at former explosive plants. The bacterium, Raoultella terrigena strain HB, isolated from a contaminated site, converts TNT into the corresponding amino products. Radio-HPLC analysis with [(14)C]TNT identified aminodinitrotoluene, diaminonitrotoluene and azoxy-dimers as the main metabolites. Transformation rate and the type of metabolites that predominated in the culture medium and within the cells were significantly influenced by the culture conditions. The NAD(P)H-dependent enzymatic reduction of nitro-substituted compounds by cell-free extracts of R. terrigena was evaluated in vitro.

Microbial community structure and function of Nitrobenzene reduction biocathode in response to carbon source switchover

“…Comamonas (2.44%) and Pseudomonas (1.72%) were relatively enriched in the bBC compared to those in the gBC despite of they dominated in the initial inoculum (Table 2) The potential function of these dominant genera mentioned above was revealed as followed. Firstly, most of the dominant genera (Escherichia, Pseudomonas, Mycobacterium, Flavobacterium, Raoultella, Enterobacter and Desulfovibrio) were capable of reducing nitroaromatics to corresponding aromatic amines or mineralization of nitroraomatics (Comamonas, Pseudomonas and Alcaligenes) (Claus et al, 2006;Ma et al, 2007;Marvin-Sikkema and de Bont, 1994;Spain, 1995) regardless of the performance mode. Subsequently, most of the dominant genera (Pseudomonas, Escherichia, Rhodopseudomonas, Ochrobactrum, Desulfovibrio, Enterobacter, Comamonas and Corynebacterium) were identified with electrochemically activity (Logan, 2009;Rosenbaum et al, 2011;Xing et al, 2010) or dominated in the biocathode (Enterococcus, Pseudomonas and Paracoccus) (Virdis et al, 2011;Wang et al, 2011) regardless of some of them dominated in the initial inoculum.…”

“…For example, Dysgonomonas and Escherichia could ferment glucose with production of volatile acid under facultative anaerobic conditions were enriched in the initial inoculum. Enterococcus (38.42%) and Raoultella (11.09%) dominated in the gBC attributed to they could reduce nitroaromatics into corresponding aromatic amines under heterotrophic cultivation (Claus et al, 2006;Rafii et al, 2003). …”

Low temperature acclimation with electrical stimulation enhance the biocathode functioning stability for antibiotics detoxification

“…Importantly, the relative abundances of Aeromonas (r ¼ À0.79, P ¼ 0.019) and Vagococcus (r ¼ À0.66, P ¼ 0.075) showed a significant negative correlation to the maximal AMCl 2 yield under the opened circuit mode (pure anaerobic bioreduction). This result strongly suggests that the low temperature acclimation with electrical stimulation enhanced the CAP nitro group reduction with dominant cold-adapted nitroreductase-carrying bacteria under 10 C. Raoultella (62.06 ± 21.72%; P ¼ 0.005) and Enterococcus (9.00 ± 10.16%) obviously or relatively enriched in the S25-biocathode attributed to the fact that they could reduce nitroaromatics into corresponding aromatic amines with glucose as electron donor (Claus et al, 2007;Rafii et al, 2003). Factually, the relative abundance of Raoultella showed a significant positive correlation to the maximal AMCl 2 yield (r ¼ 0.81, P ¼ 0.014) under the opened circuit mode.…”

Preparation and application of novel catalytic-ceramic-filler in a coupled system for TNT manufacturing wastewater treatment

“…filtered out by the fillers. Then as HRT was increased from 2.0 h to 10.0 h, the CODcr removal increased slightly at near neutral pH, possibly because of the coagulation of Fe (OH) 2 and Fe (OH) 3 . It should be note that the removal of TNT and COD for ME changed slightly after 2 h, with or without aeration, it is likely that ME reactions mainly happened on strong acidic conditions which was also demonstrated by other researchers, resulting in the majority removal of TNT and COD.…”

“…In recent years, many researchers have been focusing on TNT contained wastewater treatment [3]. The applied processes mainly include adsorption [4], alkaline hydrolysis [5], photocatalytic [6], catalytic oxidation [7], fenton oxidation [8], vacuum distillation [9] and biological treatment [10], etc.…”