Degradation of 2-Methylnaphthalene by a Sulfate-Reducing Enrichment Culture of Mesophilic Freshwater Bacteria

A. S. Galushko, U. Kiesele-Lang, A. Kappler
2003 Polycyclic aromatic compounds (Print)  
Granules of expanded clay ("Lecaton") serving as a mineral filter bed in a groundwater purification plant (Lübeck, Metallhüttengelände) were investigated for the presence of mesophilic freshwater microorganisms able to degrade monomethylated naphthalenes under oxygen-and sulfate-reducing conditions. Microorganisms inhabiting the granules readily degraded 1-methylnaphthalene and 2-methylnaphthalene in the presence of oxygen. An enrichment culture of sulfate-reducing bacteria was obtained which
more » ... ew on 2-methylnaphthalene but not on 1-methylnaphthalene. The enriched bacteria were sensitive toward high concentrations of sulfide and 207 208 A. S. Galushko et al. 2-methylnaphthalene in the medium. Naphthyl-2-methylsuccinate and 2-naphthoate were major metabolites that accumulated in cells during growth of the enrichment culture. This finding proposed that the initial reactions of 2-methylnaphthalene metabolism included addition of fumarate to the methyl group of the compound and further degradation to 2-naphthoate, analogous to toluene metabolism under anoxic conditions. However, the addition reaction was specific for 2-methylnaphthalene because none of the bacteria present in the enrichment culture was able to grow on toluene. 2-Methylnaphthalene might be degraded through cooperation of aerobic and sulfate-reducing bacteria on the basis of 2-naphthoate production and its utilization, respectively.
doi:10.1080/10406630308058 fatcat:zynxdeqoxngvvhdfr5howygxfa