Genome-Centered Metagenomics Analysis Reveals the Symbiotic Organisms Possessing Ability to Cross-Feed with Anammox Bacteria in Anammox Consortia

Abstract

Although using anammox communities for efficient wastewater treatment has attracted much attention, the pure anammox bacteria are difficult to obtain, and the potential roles of symbiotic bacteria in anammox performance are still elusive. Here, we combined long-term reactor operation, genome-centered metagenomics, community functional structure, and metabolic pathway reconstruction to reveal multiple potential cross-feedings during anammox reactor start-up according to the 37 recovered metagenome-assembled genomes (MAGs). We found Armatimonadetes and Proteobacteria could contribute the secondary metabolites molybdopterin cofactor and folate for anammox bacteria to benefit their activity and growth. Chloroflexi-affiliated bacteria encoded the function of biosynthesizing exopolysaccharides for anammox consortium aggregation, based on the partial nucleotide sugars produced by anammox bacteria. Chlorobi-affiliated bacteria had the ability to degrade extracellular proteins produced by anammox bacteria to amino acids to affect consortium aggregation. Additionally, the Chloroflexi-affiliated bacteria harbored genes for a nitrite loop and could have a dual role in anammox performance during reactor start-up. Cross-feeding in anammox community adds a different dimension for understanding microbial interactions and emphasizes the importance of symbiotic bacteria in the anammox process for wastewater treatment.

Exploring the effects of operational mode and microbial interactions on bacterial community assembly in a one-stage partial-nitritation anammox reactor using integrated multi-omics

“…The recovered abundant and/or active heterotrophs in the PNA reactor were denitrifying bacteria and provided extra nitrite/ammonium for anammox bacteria via the nitrite/ammonium loop, which was also identified in previous works [17, 20, 68]. Therefore, the assemblages of bacteria may be selected not only by the operational modes but also by the key metabolism process in the studied system.…”

Genome of a Novel Bacterium “Candidatus Jettenia ecosi” Reconstructed From the Metagenome of an Anammox Bioreactor

“…Numerous studies of anammox bioreactors revealed complex microbial communities comprising, in addition to dominant anammox planctomyctes, a number of such physiological groups, as fermentative bacteria, nitrifiers, denitrifiers, methanogens, and others (Hu et al, 2012; Gonzalez-Martinez et al, 2015a; Speth et al, 2016; Mardanov et al, 2017; Park et al, 2017; Zhao Y. et al, 2018). In order to get deeper insights into microbial community composition and reveal minor community members for which MAGs were not assembled, we analyzed raw pyrosequencing reads.…”

“…Filamentous bacteria of the phylum Chloroflexi usually account for a significant part of the microbial community of anammox-based bioreactors (Kindaichi et al, 2012; Chu et al, 2015; Wang et al, 2017) and were also detected in this study both by metagenomics and FISH analysis (Figures 2A,B). It is hypothesized that in anammox bioreactor communities Chloroflexi are involved in the degradation of organics from dead cells, or they can be involved in the synthesis or degradation of extracellular polymeric matrix (Ni et al, 2012; Speth et al, 2016; Zhao Y. et al, 2018). Due to their filamentous structure, they play an important role in the formation of biofilms (Kindaichi et al, 2012; Zhao Y. et al, 2018).…”

Island biogeography on a micro-scale: Larger anammox granules not only harbor higher species diversity but also support more functional diversity

“…Although the microbial ecology of anammox granules was studied in previous studies [22,23,25,49,50], the size-fractioned anammox granule system proposed here delineates the interactions among granules with different sizes from micro-scale view for the first time. In a recent study, the crossfeeding among microorganisms was investigated based on metagenomics analysis [50]. However, the present study touched another dimension to demonstrate the interactions between granules based on more comprehensive data (metagenomics and metatranscriptomics).…”