CEE Seminar - Biological phosphorus removal through the lens of microbial ecosystems biology

Biological wastewater treatment systems are ideal models with which to study "eco-systems biology" of microbial communities. Polyphosphate accumulating bacteria are used world-wide to remove phosphorus from wastewater but the most abundant phylogenetically defined group (Candidatus Accumulibacter) cannot be cultured in isolation. I will describe advances in our understanding of Accumulibacter ecophysiology based on comparative genomics and genome-enabled analyses of expressed genes by transcriptomics. Co-expression analysis identified ecologically relevant trend categories including genes with increased transcript abundance upon anaerobic acetate contact or oxygen contact, and genes with differential transcript abundance under low and high phosphorus concentrations, consistent with batch cycle phases. Our recent work focuses on drivers influencing genome-scale evolution and ecological dynamics. Multiple distinct Accumulibacter species co-exist in full scale wastewater treatment plants and lab-scale systems. I will discuss new evidence for the role of phage in modulating Accumulibacter abundances in lab-scale systems, as well as the ecological trade-offs within the genus.