An acclimated activated sludge was examined for its ability to degrade meta-fluorophenol as sole carbon source in aerobic batch cultures. The mechanism study revealed that the initial step in the aerobic biodegradation of meta-fluorophenol was their transformation to fluorocatechol. Following transformation of the fluorophenol to fluorocatechol, ring cleavage by catechol 1,2-dioxygenases proceeded via an ortho-cleavage pathway, then defluorination occurred. (c) 2006 Elsevier B.V. All rights reserved.