Cometabolism of the Superphylum Patescibacteria with Anammox Bacteria in a Long-Term Freshwater Anammox Column Reactor

Abstract

Although the anaerobic ammonium oxidation (anammox) process has attracted attention regarding its application in ammonia wastewater treatment based on its efficiency, the physiological characteristics of anammox bacteria remain unclear because of the lack of pure-culture representatives. The coexistence of heterotrophic bacteria has often been observed in anammox reactors, even in those fed with synthetic inorganic nutrient medium. In this study, we recovered 37 draft genome bins from a long-term-operated anammox column reactor and predicted the metabolic pathway of coexisting bacteria, especially Patescibacteria (also known as Candidate phyla radiation). Genes related to the nitrogen cycle were not detected in Patescibacterial bins, whereas nitrite, nitrate, and nitrous oxide-related genes were identified in most of the other bacteria. The pathway predicted for Patescibacteria suggests the lack of nitrogen marker genes and its ability to utilize poly-N-acetylglucosamine produced by dominant anammox bacteria. Coexisting Patescibacteria may play an ecological role in providing lactate and formate to other coexisting bacteria, supporting growth in the anammox reactor. Patescibacteria-centric coexisting bacteria, which produce anammox substrates and scavenge organic compounds produced within the anammox reactor, might be essential for the anammox ecosystem.

New Insight Into the Interspecies Shift of Anammox Bacteria Ca. “Brocadia” and Ca. “Jettenia” in Reactors Fed With Formate and Folate

“…Intraspecific interactions also take place according to the principle of quorum sensing and cross-feeding (Ding et al, 2013;Lawson et al, 2017;Zhao et al, 2018;Tang et al, 2019;Kuenen, 2020). For example, an exchange with secondary metabolites, contributing to EPS production and degradation, and thus to aggregation, and participation in nitrite loop were found between anammox bacteria and bacteria of the phyla Armatimonadetes, Proteobacteria, Chloroflexi, and Chlorobi (Zhao et al, 2018), as well as co-metabolism with Patescibacteria group (Hosokawa et al, 2021). It is assumed that one of the possible ecological roles of the bacteria of the Patescibacteria group in the anammox reactor is to provide lactate and formate to other coexisting bacteria, supporting their growth (Hosokawa et al, 2021).…”

“…For example, an exchange with secondary metabolites, contributing to EPS production and degradation, and thus to aggregation, and participation in nitrite loop were found between anammox bacteria and bacteria of the phyla Armatimonadetes, Proteobacteria, Chloroflexi, and Chlorobi (Zhao et al, 2018), as well as co-metabolism with Patescibacteria group (Hosokawa et al, 2021). It is assumed that one of the possible ecological roles of the bacteria of the Patescibacteria group in the anammox reactor is to provide lactate and formate to other coexisting bacteria, supporting their growth (Hosokawa et al, 2021). All these bacteria along with other typical members of the anammox communities were found in the present study.…”

Wastewater Treatment: Current and Future Techniques

“…Among these techniques, anaerobic ammonium oxidation (anammox) has received researchers' attention for nitrogen removal purposes. Anammox is a microbial procedure in which ammonia is oxidized to nitrogen gas, with nitrite as the electron acceptor [13]. Hosokawa et al [13] studied the cometabolism of Patescibacteria with anammox in an anammox reactor.…”

“…Anammox is a microbial procedure in which ammonia is oxidized to nitrogen gas, with nitrite as the electron acceptor [13]. Hosokawa et al [13] studied the cometabolism of Patescibacteria with anammox in an anammox reactor. On the basis of their study, Patescibacteria might play an ecological role in supplying lactate and formate to other coexisting bacteria, supporting growth in the anammox reactor.…”

Bioelectrochemical sulfate reduction enhanced nitrogen removal from industrial wastewater containing ammonia and sulfate

“…However, due to coexisting SO 4 2− , hydrogen autotrophic sulfate reduction might be a competing reaction for hydrogen autotrophic denitrification. Anammox can remove NH 4 + without organic substrates by utilizing NH 4 + as an electron donor and nitrite (NO 2 − ) as an electron acceptor 5,6 . The main problem of Anammox process is that Anammox bacteria have a very slow growth rate and are sensitive to environmental factors 7,8 .…”