Degradation of Mono-Fluorophenols by an Acclimated Activated Sludge

Abstract

Acclimated activated sludge was examined for its ability to degrade mono-fluorophenols as the sole carbon source in aerobic batch cultures. The acclimated activated sludge degraded fluorophenol efficiently. It degraded 100 mg/l 3-fluoropheno and 4-fluorophenol in 16 h with, respectively, 99.85% and 99.91% fluoride anion release and it degraded 50 mg/l 2-fluorophenol in 15 h with 99.26% fluoride anion release. The aerobic biodegradability of the mono-fluorophenols decreased in the order: 4-fluorophenol > 3-fluorophenol > 2-fluorophenol, resulting mainly from a different octanol/water partition coefficient and different steric parameter of the fluorophenols. The mechanism study revealed that the initial step in the aerobic biodegradation of mono-fluorophenols by the activated sludge 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.

Simultaneous partial nitrification and 2-fluorophenol biodegradation with aerobic granular biomass: Reactor performance and microbial communities

“…Besides, biodegradation of fluorophenols is scarcely reported. The related studies on aerobic biodegradation of fluorophenol are related to i) an acclimated activated sludge system operated in batch mode (Chaojie et al, 2007) and to ii) an aerobic granular reactor treating a readily biodegradable compound (acetate) and bioaugmented with an specific fluorophenol-degrading bacterial strain (Duque et al, 2015(Duque et al, , 2011.…”

The biodegradation vs. biotransformation of fluorosubstituted aromatics

“…No fluoropyrogallol was formed after induction with phenol alone, indicating that different phenol hydroxylases were induced in the presence or absence of 4-fluorophenol (Finkelstein et al 2000). 4-Fluorocatechol was detected as a metabolite in 4-fluorophenol degrading activated sludge (Chaojie et al 2007a), indicating mere partial transformation.…”

“…Degradation of both 2-fluorophenol and 3-fluorocatechol was furthermore reported to occur in acclimated activated sludge (Chaojie et al 2007a). The degradative pathway for 2-fluorophenol was suggested to proceed via 3-fluorocatechol and productive use of 2-fluoromuconic acid, because no unsubstituted catechol was found in the medium, 3-fluorocatechol was formed only transiently, and no accumulation of fluoromuconic acid was observed despite catechol 1, 2-dioxygenase activity in the culture.…”

“…Growth, however, could not be observed. A dienelactone and 2-fluoromuconic acid were identified as intermediates during degradation of 3-fluorocatechol by activated sludge (Chaojie et al 2007a). A two-component monooxygenase from Rhodococcus sp.…”

Isolation and characterization of a Rhodococcus strain able to degrade 2-fluorophenol

“…Aerobic biotransformation of 2-FP by several Rhodococcus strains (Bondar et al 1999;Finkelstein et al 2000), acclimated activated sludge (Chaojie et al 2007), Gloeophyllum striatum (Kramer et al 2004) and Penicillium strains (Hofrichter et al 1994;Marr et al 1996), has been reported. In all cases, 2-FP was degraded by cometabolism in the presence of other carbon sources.…”