EFFECTS OF 6 DIFFERENT FUNCTIONAL-GROUPS AND THEIR POSITION ON THE BACTERIAL METABOLISM OF MONOSUBSTITUTED PHENOLS UNDER ANAEROBIC CONDITIONS

The biodegradability of phenol and all isomers of aminophenol (AP), ch lorophenol (CP), hydroxybenzoate (HE), dihydroxybenzene (DHB), methylp henol (MP), and nitrophenol (NP)were examined under denitrifying and m ethanogenic conditions. All isomers of CP and NP inhibited denitrifica tion, while each NP isomer was reduced to AP under methanogenic condit ions. All CPs were stoichiometrically mineralized to CH4. All AP isome rs were mineralized under denitrifying conditions, while only the 4-AP isomer was biodegraded under methanogenic conditions. Under denitrify ing conditions, the 1,3-DHB and 1,4-DHB isomers were mineralized, whil e the 1,2-DHB was persistent. 1,2-DHB was reductively dehydroxylated t o phenol under methanogenic conditions. All MPs were mineralized under both anaerobic conditions. 2-MP incubated under methanogenic conditio ns and the 4-MP incubated under denitrifying conditions underwent meth yl group oxidation to 2-hydroxybenzyl alcohol and 4-hydroxybenzoate, r espectively. All HE isomers incubated under both anaerobic conditions produced stoichiometric quantities of N-2 and CH4. These results sugge st that the anaerobic condition and the nature of the substituent can influence the metabolism and toxicity of phenolic compounds.