Population Analysis of Cyanobacteria in Rotating Algal Biofilm Reactors

Algal biofilms have numerous applications in wastewater treatment and bioproduct production. The Sustainable Waste-to-Bioproducts Engineering Center at Utah State University is working to develop rotating algal biofilm reactors (RABRs) to remove excess nitrogen and phosphorus from wastewater effluent while producing biomass for downstream production. Genetic analysis of algal biofilms on various RABRs was performed to gain improved understanding of the biofilm populations. This analysis focuses on a pilot-scale RABR and how it compares to several other RABRs. Additionally, old methods of genetic analysis filtered out important cyanobacterial populations. A new method was developed to identify the cyanobacteria within the biofilms. Analysis indicated higher diversity in the pilot RABR and trickling filter biofilms. Furthermore, I showed that the pilot RABR had consistent diversity over time. Several key biofilm organisms were identified including Synechococcus, Chlorella, and multiple varieties of Proteobacteria. I also developed an analysis using a software package called DADA2 that was better at detecting cyanobacteria within the algal biofilms, however the analysis did have lower taxonomic specificity.