Molecular characterisation of two anaerobic phenol-degrading enrichment cultures

The microbial composition of two phenol-degrading enrichment cultures was characterised using molecular techniques and by analysing their degradation capacity. The cultures originate from two different anaerobic bioreactors treating organic household waste at mesophilic and thermophilic temperature. The results showed that two unique community structures had developed, with the ability to partially or completely degrade phenol and 4-hydroxybenzoate. These compounds were degraded at temperature up to 48 °C in both cultures. Phylogenetic analysis confirmed the presence of one conceivable phenol degrader in each culture; one affiliated to subcluster Ih in the phylum Desulfotomaculum and the other to the family Syntrophorhabdaceae in the phylum delta Proteobacteria. This study confirms the importance of both these clusters for bacteria degrading aromatic compounds, especially phenols and phthalate isomers, under methanogenic conditions.