Compared microbiology of granular sludge under autotrophic, mixotrophic and heterotrophic denitrification conditions

N. Fernandez, R. Sierra-Alvarez, R. Amils, J. A. Field, J. L. Sanz

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Water contamination by nitrate is a wideworld extended phenomena. Biological autotrophic denitrification has a real potential to face this problem and presents less drawbacks than the most extended heterotrophic denitrification. Three bench-scale UASB reactors were operated under autotrophic (R1, H2S as electron donor), mixotrophic (R2, H2S plus p-cresol as electron donors) and heterotrophic (R3, p-cresol as electron donor) conditions using nitrate as terminal electron acceptor. 16S rDNA genetic libraries were built up to compare their microbial biodiversity. Six different bacteria phyla and three archaeal classes were observed. Proteobacteria was the main phyla in all reactors standing out the presence of denitrifiers. Microorganisms similar to Thiobacillus denitrificans and Acidovorax sp. performed the autotrophic denitification. These OTUs were displaced by chemoheterotrophic denitrifiers, especially by Z./mr?otoacter-like and Offoi/wa-like OTUs. Other phyla were Bacteroidetes, Chloroflexi, Firmicutes and Actinobacteria that- as well as Archaea members- were implicated in the degradation of organic matter, as substrate added as coming from endogenous sludge decay under autotrophic conditions. Archaea diversity remained low in all the reactors being Methanosaeta concilil the most abundant one.

Original languageEnglish (US)
Pages (from-to)1227-1236
Number of pages10
JournalWater Science and Technology
Issue number6
StatePublished - 2009


  • Autotrophic Denitrification
  • Denetic Library
  • Granular Sludge
  • Heterotrophic Denitrification
  • Microbial Biodiversity
  • UASB Reactor

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology


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