Picric acid (2,4,6-Trinitrophenol), a derivative of phenol, is a yellow solid. Picric acid is mainly used in manufacture of explosives and as an intermediate in dye manufacturing. Both 2,4,6-trinitrophenol and 2,4-dinitrophenol are found in the waste streams released into the environment by aniline production plants. The three nitro groups of picric acid create a highly positive redox potential that is susceptible to reductive rather than oxidative processes. An initial reductive attack on the aromatic ring converts picric acid to the hydride-TNP Meisenheimer complex. In Rhodococcus (opacus) erythropolis HL PM-1 ([http://www.ncbi.nlm.nih.gov/pubmed/1444408|Lenke et al., 1992]), Nocardioides sp. strain CB 22-2 ([http://www.ncbi.nlm.nih.gov/pubmed/10103224|Behrend and Heesche-Wagner, 1999]) and Nocardioides simplex (formerly Arthrobacter) FJ2-1A, ([http://www.ncbi.nlm.nih.gov/pubmed/10217752|Ebert et al., 1999]) elimination of nitrite is thought to proceed through this intermediate. However, [http://www.ncbi.nlm.nih.gov/pubmed/9973345|Rieger et al. (1999)] states this elimination requires an unlikely C-3 to C-2 hydrogen migration. Studies show that C-2 protonation of the hydride species occurs readily at physiological pH and suggests the protonated hydride complex is the reactive intermediate for nitrite elimination to 2-dinitrophenol. Reduction of the aromatic nucleus in 2,4-DNP forms the hydride-DNP Meisenheimer complex. A second pathway involves a two component enzyme system which catalyzes two hydration reactions of picric acid to form a dihydride Meisenheimer-complex ([http://www.ncbi.nlm.nih.gov/pubmed/11882715|Heiss et al. 2002]). The nitro form of this dihydride complex remains as a dead-end metabolite; the aci form undergoes elimination of nitrite, after which the two metabolic pathways of picric acid merge ([http://www.ncbi.nlm.nih.gov/pubmed/11995829|Ebert et al., 2001]). The enzyme catalyzing denitration of the dihydride Meisenheimer-complex of picric acid to form the hydride Meisenheimer-complex of 2,4-dinitrophenol and also the hydrolase enzyme for subsequent reaction have been recently purified ([http://www.ncbi.nlm.nih.gov/pubmed/15128543|Hofmann et al., 2004]). It has been known for more than a decade that 4,6-dinitrohexanoate undergoes further mineralization, with a minor amount remaining as a dead-end metabolite ([http://www.ncbi.nlm.nih.gov/pubmed/1444407|Lenke et al., 1992]). However the further metabolites have not yet been identified.