Methanogenic diversity in anaerobic bioreactors under extremely high ammonia levels

Baris Calli*, Bulent Mertoglu, Bulent Inanc, Orhan Yenigun

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

91 Citations (Scopus)


To evaluate the effects of high free ammonia nitrogen on methanogens, five laboratory scale UASB reactors seeded with different sludges were operated for 450 days. Throughout the experimental period, free ammonia concentration was gradually elevated up to 750 mg/l. Changes in methanogenic population were investigated by using 16S rDNA/rRNA based molecular methods such as denaturing gradient gel electrophoresis (DGGE), fluorescent in situ hybridization (FISH), cloning and DNA sequencing. Generally, in all of the reactors, moderately high COD removal was achieved in the range of 77-96%. However, in three of the reactors, propionate degradation and in one of them, acetate removal was influenced more severely. In no way, neither of the phases was inhibited in reactor 4 (R4), which was seeded with a biomass concentrated from a landfill leachate. On the other hand, as free ammonia level elevated, instead of a community shift, single coccus shaped Methanosarcina cells previously predominant at low free ammonia concentrations turned into stringent multicellular units, in all of the reactors.

Original languageEnglish
Pages (from-to)448-455
Number of pages8
JournalEnzyme and Microbial Technology
Issue number4
Publication statusPublished - 1 Sept 2005
Externally publishedYes


Authors would like to acknowledge the financial support of Bogazici University Research Fund, (Project No.: 01Y101D) and TUBITAK (ICTAG A034 and A036).

FundersFunder number
Bogazici University Research Fund01Y101D


    • DGGE
    • FISH
    • Free ammonia
    • Methanosarcina
    • Propionate


    Dive into the research topics of 'Methanogenic diversity in anaerobic bioreactors under extremely high ammonia levels'. Together they form a unique fingerprint.

    Cite this