Comprehensive characterization of filamentous bacteria from the phylum Chloroflexota in global resource recovery facilities

Members from the Chloroflexota phylum are diverse and highly abundant in activated sludge, mostly characterized by filamentous morphology and sometimes associated with bulking and foaming. However, some abundant genera are still uncharacterized. The MiDAS 4 global survey was used to analyse the abundance and distribution of these microorganisms. In addition, new fluorescence in situ hybridization probes were designed and revealed a high diversity in morphology. High-quality metagenome assembled genomes retrieved from the Danish wastewater treatment plants, were used for metabolic reconstruction. Genome annotation revealed their possible involvement in degradation of carbohydrates and utilization of different sugars, with the ability to ferment. FISH-Raman confirmed metabolic prediction of glycogen accumulation. These results are highlighting the importance of this abundant group of bacteria in nutrient transformation during wastewater treatment.