Tools for Metagenomic Analysis at Wastewater Treatment Plants:Application to a Foaming Episode

Metagenomic analysis is a powerful approach for wholesale characterizations of microbial populations like those that operate within municipal wastewater treatment plants. It is well known that many problems are associated with the overgrowth or undergrowth of specific bacterial genera. We describe a database of the combined metagenomes of activated sludge aeration basins from around the globe and use it as a reference to study the population of a foamy activated sludge aeration basin. We show that foam production is associated with blooms of mycolic acid producing genera, especially Mycobacterium. We confirm this bloom using the acid-fast stain, and we show that genes involved with mycolic acid production are enriched in the foam-producing sample. In addition, we show that this sample has unusual nitrifying populations. We suggest that low-cost DNA sequencing and publicly available tools for shotgun metagenomic analyses, including those described here, might broadly facilitate wastewater treatment plant operation.