Anaerobic metabolism of resorcyclic acids (m-dihydroxybenzoic acids) and resorcinol (1,3-benzenediol) in a fermenting and in a denitrifying bacterium

The anaerobic metabolism of 2,4- and 2,6-dihydroxybenzoic acid (beta- and gamma-resorcyclic acid) and 1,3-benzenediol (resorcinol) was investigated in a fermenting coculture of a Clostridium sp. with a Campylobacter sp. and in a newly isolated denitrifying gram-negative bacterium. The enzymes of this pathway were searched for and partly characterized in vitro. It is shown that resorcyclic acids are decarboxylated in both organisms by specific enzymes, 2,4- or 2,6-dihydroxybenzoic acid decarboxylase. It is concluded that two different pathways of anaerobic 1,3-benzenediol metabolism exist.