Biodegradation of resorcinol and catechol by denitrifying enrichment cultures

We examined the anaerobic degradation of catechol (1,2- dihydroxybenzene), resorcinol (1,3-dihydroxybenzene), and hydroquinone (1,4- dihydroxybenzene), which are widely used industrial reagents and central intermediates in the biodegradation of numerous aromatic compounds. Anaerobic denitrifying enrichments were established with sediments from an estuarine tidal strait in New Jersey, USA. The three dihydroxybenzene isomers were provided as a sole carbon source in separate enrichment series. Resorcinol- and catechol-degrading consortia used their respective substrates over repeated feedings. Initial loss of hydroquinone was observed, but activity could not be maintained. The degradation of resorcinol and catechol was coupled to denitrification and was dependent on nitrate or nitrite as an electron acceptor. Nitrate consumption and N₂ production corresponded to the stoichiometric values predicted for the oxidation of dihydroxybenzenes to CO₂.