Anaerobic transformation of 2,4,6-trinitrotoluene by Clostridium acetobutylicum
Khan, Tariq A.
Hughes, Joseph B.
Master of Science
In this work, rapid TNT ($>$150 mg/L) transformation by Clostridium acetobutylicum via a reductive pathway to monoaminonitrotoluenes, diaminonitrotoluenes, and on to undetectable end products was observed. The maximum velocities were greatest for TNT reduction, followed by 2A46DNT, 4A26DNT, and 24DA6NT. Initial reduction was preferred at the para position. The measured TNT transformation rates were considerably higher than those observed by others. The transformation of hydroxylamino intermediates was rate limiting. Rates and extents of transformation of TNT and its metabolites were affected by the organism's growth phase. When TNT was added in the early acidogenic phase, rapid transformation to undetectable compounds occurred. When added at the end of exponential growth, TNT and its intermediates were recalcitrant. The decline in transformation was putatively due to ferrodoxin and electron transfer inactivity. The results show potential for this organism to remediate TNT contamination, as in an ex situ bioslurry reactor amended with soluble glucose (sugar).
Environmental science; Chemical engineering; Microbiology; Biology; Engineering