Poster Presentation 3-64

Aerobic Biodegradation of 2,6-Dinitrotoluene in

Aqueous Solution by a Mixed Culture

Jan Paca¹, Jiri Barta¹, Rakesh Bajpai² and Marie Stiborova³

¹Department of Biotechnology, Institute of Chemical Technology,

Technicka 5, CZ-166 28 Prague, Czech Republic

²Department of Chemical Engineering

University of Missouri

Columbia, MO 65211, USA

³Charles University, CZ-128 40

Prague, Czech Republic

Telephone:  (573) 882-3708; Fax:  (573) 882-4940; E-mail:  bajpair@missouri.edu

A mixed culture enriched from aged TNT-contaminated soil from Synthesia Company (Pardubice, Czech Rep.) was used to study biodegradation of 2,6-dinitrotoluene (2,6DNT) in aqueous solution under aerobic conditions at 26°C.  The study was conducted in shake flasks containing basal salt medium.  The medium was supplemented with either glycerol or sodium succinate as primary carbon sources.  In one set of experiments, no carbon source other than 2,6DNT was added and nitrate was eliminated in order to force the cells to utilize 2,6DNT as a nitrogen source as well.  Initial concentrations of 2,6DNT in the aqueous solution ranged from 5.5 - 10.0 mg/L.  The cells were not able to grow on 2,6DNT as the sole carbon, nitrogen, and energy source.  The cell growth, as measured by optical density at 400 nm, was abundant in the carbon-supplemented media.  Aqueous phase optical density peaked in 1-2 days in glycerol- and succinate-supplemented media, then declined over the next week.  The concentration of 2,6DNT was reduced to non-detectable levels within seven days in the glycerol-supplemented medium.  The degradation rate of 2,6DNT was slower in the succinate-supplemented medium.  Based on the liquid chromatographic analyses of the samples, up to two intermediates were observed in the medium but significant accumulation took place in only one of the intermediates in the succinate medium.

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