An anaerobic phthalate isomer-degrading strain (JTT) that we previously isolated was characterized. In addition, a strictly anaerobic, mesophilic, syntrophic phthalate isomer-degrading bacterium, designated strain JIT, was isolated and characterized in this study. Both were non-motile rods that formed spores. In both strains, the optimal growth was observed at temperatures around 37°C and neutral pH. In syntrophic co-culture with the hydrogenotrophic methanogen Methanospirillum hungatei, both strains could utilize two or three phthalate isomers for growth, and produce acetate and methane as end products. Strain JTT was able to grow on isophthalate, terephthalate, and a number of low-molecular weight aromatic compounds, such as benzoate, hydroquinone, 2-hydroxybenzoate, 3-hydroxybenzoate, 2,5-dihydroxybenzoate, 3-phenylpropionate in co-culture with M. hungatei. It could also grow on crotonate, hydroquinone and 2,5-dihydroxybenzoate in pure culture. Strain JIT utilized all of the three phthalate isomers as well as benzoate and 3-hydroxybenzoate for growth in co-culture with M. hungatei. No substrates were, however, found to support the axenic growth of strain JIT. Neither strain JTT nor strain JIT could utilize sulfate, sulfite, thiosulfate, nitrate, fumarate, Fe (III) or 4-hydroxybenzoate as electron acceptor. Phylogenetically, strains JTT and JIT were relatively close to the members of the genera Pelotomaculum and Cryptanaerobacter in 'Desulfotomaculum lineage I'. Physiological and chemotaxonomic characteristics indicated that the two isolates should be classified into the genus Pelotomaculum, creating two novel species for them. Here, we propose Pelotomaculum terephthalicum sp. nov. and Pelotomaculum isophthalicum sp. nov. for strain JTT and strain JIT, respectively. The type strains are strains JTT (= DSM 16121T = JCM 11824T = NBRC 100523T) and JIT (= JCM 12282T = BAA-1053T) for P. terephthalicum and P. isophthalicum, respectively.
- Anaerobic phthalate-oxidation
- Pelotomaculum isophthalicum sp. nov.
- Pelotomaculum terephthalicum sp. nov.
ASJC Scopus subject areas
- Molecular Biology