Anaerobic biotransformation of pyridine in estuarine sediments

The potential for biotransformation of pyridine in sediments from the Tsengwen River was examined. Along the river, from a freshwater (0.0% salinity) to an oceanic (3.7% salinity) environment, sediment was collected from five sampling stations. Sediment slurries were incubated in an anaerobic mineral salts medium that was amended with sulfate or sulfate plus Fe(OH)3 or MnO2. In sulfate amended sediment slurries, pyridine was removed only in the sediment slurries collected from the oceanic site. Amendment of amorphous Fe(OH)3 or MnO2 in addition to sulfate greatly facilitated the onset of pyridine removal in the sediment slurries collected from the freshwater site but not in the sediment slurries collected from the more saline sites. Addition of BESA or molybdate into Fe(OH)3 amended sediment slurries sometimes enhanced pyridine removal and sometimes inhibited pyridine removal. In MnO2 amended sediment slurries, addition of BESA enhanced pyridine removal, while addition of molybdate inhibited pyridine removal.