Pseudomonas putida utilized methyl parathion as sole carbon and (or) p
hosphorus source. The bacterium elaborated the enzyme organophosphorus
acid anhydrase, which hydrolyzed methyl parathion to p-nitrophenol. p
-Nitrophenol was further degraded to hydroquinone and 1,2,4-benzenetri
ol. The final ring compound, 1,2,4-benzenetriol, was cleaved by benzen
etriol oxygenase to maleyl acetate.