Pyridine degradation and heterocyclic nitrification by Bacillus coagulans

A gram-positive, pyridine-degrading microorganism identified as Bacillus coagulans has been isolated from contaminated soil by enrichment culture technique. Pyridine was used as sole source of carbon, nitrogen, and energy. Bacillus coagulans has a unique potential to reduce nitrogen from aromatic ring to ammonia and subsequently heterotrophically to nitrite and nitrate. The maximum degradation of pyridine was 94.1% within 72 h at 30 degrees C with a 7.57-h doubling time. The study suggests possible existence of aromatic degradation and heterotrophic nitrification in Bacillus coagulans.