Characterization of a Microbial Community in an Anammox Process Using Stored Anammox Sludge

Abstract

This study investigated a rapid start-up anaerobic ammonium oxidation (Anammox) process by inoculation with stored Anammox sludge and characterized the associated microbial communities. The Anammox process took only 43 days to start. A high nitrogen removal rate of 1.13 kg N m −3 d −1 and a nitrogen loading rate of 1.28 kg N m −3 d −1 were achieved. The ratio of ammonium removal to nitrite removal to nitrate production (1:1:0.2) was slightly lower than the theoretical value, which indicated nitrogen removal by denitrification in the reactor. Illumina high-throughput sequencing of sludge samples confirmed the co-existence of Anammox bacteria and denitrifying bacteria in the reactor and demonstrated that denitrifying bacteria play a role in nitrogen removal during the Anammox process. The dominant microbes in the reactor were Proteobacteria, Chlorobi, Chloroflexi, and Planctomycetes. However, only one species of Anammox bacteria, Candidatus jettenia, was identified and had an abundance of 4.92%. Our results illustrate the relationship between Anammox reactor performance and microbial community succession.

Metagenomic Insights Into Competition Between Denitrification and Dissimilatory Nitrate Reduction to Ammonia Within One-Stage and Two-Stage Partial-Nitritation Anammox Bioreactor Configurations

“…We focused the analysis of recovered MAGs on the genomic properties of high abundance populations that differed in abundance between reactor configurations to develop hypotheses of how the selective pressures imposed by the distinct reactor configurations may impact the microbial community structures and their potential functions. Previous studies of PNA bioreactors have observed microbial community structures over time, with some stability observed in bench scale reactors ( Chen et al, 2017 ) and conversely, community dynamics have been observed that correlated with changes in influent ammonia and nitrite concentrations ( Huang Q. et al, 2018 ). The community structure and potential function of PNA granules is also impacted by granule size, with nitrifiers being more abundant in smaller granules and larger granules harboring greater species diversity ( Luo et al, 2017 ).…”