Anaerobic degradation of α-resorcylate by a nitrate-reducing bacterium, Thauera aromatica strain AR-1

A facultatively anaerobic bacterium growing with alpha-resorcylate (3,5-dihydroxybenzoate) and nitrate was isolated from activated sludge. Cells of strain AR-1 were Gram-negative, motile rods with a G+C content of the DNA of 66.4 +/- 0.3 mol%. Strain AR-1 was assigned to the species Thauera aromatica on the basis of 16S rRNA sequence analysis. It oxidized alpha-resorcylate (3,5-dihydroxybenzoate) completely to CO2 with concomitant reduction of nitrate to N-2. in the presence of nitrate, strain AR-1 grew with short-chain fatty acids, alcohols, and benzoate derivatives. Sugars, long-chain dicarboxylic acids, and phenolic compounds such as resorcinol and phloroglucinol were not degraded. Although strain AR-1 was able to grow aerobically with, e.g., benzoate no aerobic growth was found with alpha-resorcylate as substrate. Only nitrite or nitrous oxide was used as alternative electron accepters.