2,4,6-trinitrotoluene reduction by hydrogenase in Clostridium acetobutylicum
Watrous, Mary Margaret
Hughes, Joseph B.
Master of Science
Unique genetic modifications to C. acetobutylicum altered the level of hydrogenase expression, allowing study of the resulting effects on the 2,4,6-trinitrotoluene (TNT) reduction rates to be possible. A strain designed to over-express the hydrogenase gene resulted in maintained TNT reduction during late growth phases when it is not typically observed. Strains exhibiting under-expression of hydrogenase produced slower TNT rates of reduction correlating to the expected inhibition of each strain type. Hydrogenase activity, measured by hydrogen production, in Clostridium acetobutylicum correlates strongly (R2 = 0.89) to TNT reduction rates. Indications suggested that hydrogenase potentially played an integral role in catalysis of TNT transformation by reducing its nitro substituents to the corresponding hydroxylamines. A mechanistic pathway is proposed by which this transformation takes place and may enhance the understanding of commonly found hydrogenases in other microorganisms and their ability to transform nitroaromatic compounds.
Microbiology; Biochemistry; Environmental engineering