Acclimation of a methanogenic consortium to a mixture of hydroxylated aromatic compounds

Using an anaerobic model-soil column, a non acclimated methanogenic mixed culture was exposed to increasing loading rates of a mixture of hydroxylated aromatic compounds in the presence of citrate as growth substrate. The toxic mixture consisted of 2,4,6-trichlorophenol (TCP), 1-naphthol and 2-nitrophenol (2NP). The results showed that the period of methanogenic adaptation to this mixture of chemicals, as reflected by durable methane production, was relatively long (more than 200 days). TCP was transformed to 4-chlorophenol (4CP). The biotransformation of 2NP resulted in the formation of 2-aminophenol (2AP). The maximum degradation rates observed were 25 mg/l. d, 18 mg/1. d, 22 mg/1. d and 7 mg/l. d for 2NP, 1-naphthol, TCP and 4CP respectively. 1-Naphthol, TCP and 2NP degradations do not seem to be directly related to methane production.