Effects of dissolved oxygen and pH on nitrous oxide production rates in autotrophic partial nitrification granules

Rathnayake M L D Rathnayake; Mamoru Oshiki; Satoshi Ishii; Takahiro Segawa; Hisashi Satoh; Satoshi Okabe

doi:10.1016/j.biortech.2015.08.054

Effects of dissolved oxygen and pH on nitrous oxide production rates in autotrophic partial nitrification granules

Bioresour Technol. 2015 Dec:197:15-22. doi: 10.1016/j.biortech.2015.08.054. Epub 2015 Aug 21.

Authors

Rathnayake M L D Rathnayake¹, Mamoru Oshiki², Satoshi Ishii³, Takahiro Segawa⁴, Hisashi Satoh⁵, Satoshi Okabe⁶

Affiliations

¹ Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Sapporo 060-8628, Japan. Electronic address: englashi@gmail.com.
² Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Sapporo 060-8628, Japan; Department of Civil Engineering, Nagaoka National College of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan. Electronic address: oshiki@nagaoka-ct.ac.jp.
³ Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Sapporo 060-8628, Japan; Department of Soil, Water, and Climate, BioTechnology Institute, University of Minnesota, 140 Gortner Laboratory of BioChemistry, 1449 Gortner Avenue, St. Paul, MN 55108-1095, USA. Electronic address: ishi0040@umn.edu.
⁴ Transdisciplinary Research Integration Center, National Institute of Polar Research, 10-3 Midori-cho, Tachikawa, Tokyo 190-8518, Japan. Electronic address: segawa@nipr.ac.jp.
⁵ Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Sapporo 060-8628, Japan. Electronic address: qsatoh@eng.hokudai.ac.jp.
⁶ Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Sapporo 060-8628, Japan. Electronic address: sokabe@eng.hokudai.ac.jp.

PMID: 26318242
DOI: 10.1016/j.biortech.2015.08.054

Abstract

The effects of dissolved oxygen (DO) and pH on nitrous oxide (N2O) production rates and pathways in autotrophic partial nitrification (PN) granules were investigated at the granular level. N2O was primarily produced by betaproteobacterial ammonia-oxidizing bacteria, mainly Nitrosomonas europaea, in the oxic surface layer (<200μm) of the autotrophic PN granules. N2O production increased with increasing bulk DO concentration owing to activation of the ammonia (i.e., hydroxylamine) oxidation in this layer. The highest N2O emissions were observed at pH 7.5, although the ammonia oxidation rate was unchanged between pH 6.5 and 8.5. Overall, the results of this study suggest that in situ analyses of PN granules are essential to gaining insight into N2O emission mechanisms in a granule.

Keywords: 16S rRNA gene deep sequencing; Autotrophic partial nitrification granule; Dissolved oxygen effect; N(2)O emissions; N(2)O microsensor.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Bioreactors / microbiology*
Hydrogen-Ion Concentration
Nitrification
Nitrosomonas europaea / metabolism*
Nitrous Oxide / analysis
Nitrous Oxide / chemistry
Nitrous Oxide / metabolism*
Oxygen / chemistry*

Substances

Nitrous Oxide
Oxygen