Denitrifying bacteria active in woodchip bioreactors at low-temperature conditions

Jeonghwan Jang, Emily L. Anderson, Rodney T. Venterea, Michael J. Sadowsky, Carl J. Rosen, Gary W. Feyereisen, Satoshi Ishii

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Woodchip bioreactor technology removes nitrate from agricultural subsurface drainage by using denitrifying microorganisms. Although woodchip bioreactors have demonstrated success in many field locations, low water temperature can significantly limit bioreactor efficiency and performance. To improve bioreactor performance, it is important to identify the microbes responsible for nitrate removal at low temperature conditions. Therefore, in this study, we identified and characterized denitrifiers active at low-temperature conditions by using culture-independent and -dependent approaches. By comparative 16S rRNA (gene) analysis and culture isolation technique, Pseudomonas spp., Polaromonas spp., and Cellulomonas spp. were identified as being important bacteria responsible for denitrification in woodchip bioreactor microcosms at relatively low temperature conditions (15∘C). Genome analysis of Cellulomonas sp. strain WB94 confirmed the presence of nitrite reductase gene nirK. Transcription levels of this nirK were significantly higher in the denitrifying microcosms than in the non-denitrifying microcosms. Strain WB94 was also capable of degrading cellulose and other complex polysaccharides. Taken together, our results suggest that Cellulomonas sp. denitrifiers could degrade woodchips to provide carbon source and electron donors to themselves and other denitrifiers in woodchip bioreactors at low-temperature conditions. By inoculating these denitrifiers (i.e., bioaugmentation), it might be possible to increase the nitrate removal rate of woodchip bioreactors at low-temperature conditions.

Original languageEnglish (US)
Article number635
JournalFrontiers in Microbiology
Volume10
Issue numberAPR
DOIs
StatePublished - 2019

Bibliographical note

Funding Information:
This work was supported by Minnesota Department of Agriculture (Project No. 108837) and the Minnesota’s Discovery, Research and InnoVation Economy (MnDRIVE) initiative of the University of Minnesota. EA was supported, in part, by the USDA North Central Region Sustainable Agriculture Research and Education (NCR-SARE) Graduate Student Grant Program.

Publisher Copyright:
Copyright © 2019 Jang, Anderson, Venterea, Sadowsky, Rosen, Feyereisen and Ishii. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

Keywords

  • Cellulomonas
  • Denitrification
  • Drainage
  • Nitrate removal
  • Woodchip bioreactor

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