Christopher Olivares

Chemical and Environmental Engineering

Biotransformation and Microbial Toxicity of 2.4-dinitroanisole (DNAN)
2,4-dinitroanisole (DNAN) is an insensitive munitions compound considered to replace conventional explosives like 2,4,6-trinitoluene (TNT) because it is more stable and safer to handle; however, little is known about the environmental fate of DNAN. As its use becomes more popular, releases to the environment may pose a threat to ecosystems and public health. We are currently studying studied how bacteria in wastewater sludge and in soils transform DNAN to study its environmental fate. Our objective is to find out what products are formed by the microorganisms, as well as to study their toxicity. To do so, we have performed biotransformation and toxicity batch bioassays, where we added an inoculum source (soil or sludge), the pollutant (DNAN), and a basal medium to give essential nutrients to the microorganisms. In general, we have found out that bacteria reduce the nitro groups to amines. Afterwards, these products coupled to form azo and hydrazine dimers. Microbial toxicity tests showed that DNAN was particularly inhibitory and more toxic than its main monomeric metabolites. While the transformation of DNAN to aromatic amines is a detoxification process, some intermediate products, such as polymerized aromatic amines, may still pose a toxicological concern. Globally, our results suggest that reductive biotransformation is an important fate of DNAN in anaerobic environments leading to the formation of aromatic amines as well as dimeric metabolites. These insights about the fate and biotransformation of DNAN will help to provide clues for the bioremediation of DNAN pollution.