Ammonia-oxidizing bacteria and nitrite-oxidizing bacteria (AOB and NOB) catalyze nitrification and are key drivers of the nitrogen cycle. As nitrification is an important step of nitrogen removal from sewage, AOB and NOB are essential bacteria in most wastewater treatment plants. However, both groups are understudied as most nitrifiers are uncultured and the few cultured strains are hard to maintain in the lab. Studying these recalcitrant organisms is a challenge, and the still limited knowledge of their biology sharply contrasts the immense ecological importance of nitrification. To help fill in information gaps, this project seeks to use a novel method, based on Raman microspectroscopy, to tentatively identify AOB and NOB microcolonies in unfixed activated sludge based on their high cytochrome content. There is evidence of a high microdiversity of nitrifiers in activated sludge in wastewater treatment plants, which suggests a hitherto overlooked extent of niche partitioning among these organisms, which may result from a high genomic plasticity and novel, ecologically relevant biological traits.
Proposer’s Name: Michael Wagner