Microbial communities in anammox reactors: a review

ABSTRACT

The anammox (anaerobic ammonium oxidation) process has been used to remove nitrogen from wastewaters and is considered a promising approach due to its advantages over conventional processes (nitrification and denitrification). The development of molecular biology tools has allowed for great advances in describing the microbial communities in anammox reactors, which is important to understand the complex reactions and interactions that occur inside these systems. This study presents a review of the microbial diversity studies in anammox reactors. Several researchers have investigated the microbial community composition in anammox reactors, in order to elucidate the roles that the different microbial groups (besides the anammox bacteria) play in these systems. The microbial communities of anammox reactors appear to be affected by several factors, such as the configuration of the reactors, the biomass growth mode inside of the reactors, operational conditions and type of inoculum used for start-up. However, independent of reactors characteristics, some microbial groups such as Proteobacteria and Chloroflexi have always been found with Planctomycetes in anammox reactors. Moreover, other microbial groups such as Chlorobi, Acidobacteria and Bacteroidetes are often detected in these systems. Identifying the roles and interactions of such microorganisms inside anammox reactors is a great challenge for future studies.

KEYWORDS:

• Anaerobic ammonium oxidation (anammox)
• nitrogen removal
• microbial communities
• molecular biology
• next-generation sequencing

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Alyne Duarte Pereira http://orcid.org/0000-0001-9364-0573

Angela Cabezas http://orcid.org/0000-0001-5460-019X

Claudia Etchebehere http://orcid.org/0000-0003-2495-205X

Carlos Augusto de Lemos Chernicharo http://orcid.org/0000-0001-7226-8266

Juliana Calábria de Araújo http://orcid.org/0000-0002-5497-8675

Additional information

Funding

This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico do Brasil (CNPq) [grant number 481405/2013-5], Fundação de Amparo à Pesquisa de Minas Gerais (FAPEMIG) [grant number APQ-02669-14] and Coordenação de Aperfeiçoamento de Pessoal de nível Superior (CAPES) [grant number 486/2014].