Characterization of microorganisms contributing to denitrification in tile drain biofilters in illinois

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Agricultural nitrates are thought to be a primary cause of the large hypoxic zone in the Gulf of Mexico. Subsurface woodchip biofilters developed at the University of Illinois remove on average 50-60% of nitrates from tile drains, and in some cases achieve complete removal during periods of low flow. Soil microorganisms that colonize the biofilters transform aqueous nitrate to inert nitrogen gas by the denitrification pathway. However, beyond this basic mechanism, understanding of how the biofilters function has previously been largely superficial. In particular, characterization of individual species contributing to denitrification and the overall microbial community could enable better monitoring, optimization, and control of biofilters. In this study, the type(s) of organisms contributing to denitrification were characterized using denitrification enzyme assays of woodchip samples under inhibition with either tetracycline (to inhibit bacteria) or cycloheximide (to inhibit fungi). Under tetracycline inhibition, denitrification was reduced almost to zero, suggesting that denitrification is mediated primarily by bacterial populations. However, under cycloheximide inhibition denitrification was also reduced to 30-40% of uninhibited levels. Because fungal denitrification should have resulted in activity in the presence of tetracycline, which was not observed, we hypothesize that the cycloheximide inhibition is indirect. For example, inhibiting fungal metabolism may block fungi from releasing organic substrate molecules to bacteria from the woodchips. Current work is focused on identification of particular species and characterization of the microbial community within biofilters using fluorescence in-situ hybridization (FISH) and automated ribosomal intergenic spacer analysis (ARISA).

Original languageEnglish (US)
Title of host publicationAmerican Society of Agricultural and Biological Engineers Annual International Meeting 2008, ASABE 2008
PublisherAmerican Society of Agricultural and Biological Engineers
Pages5605-5614
Number of pages10
Volume9
ISBN (Print)9781605605364
StatePublished - 2008
EventAmerican Society of Agricultural and Biological Engineers Annual International Meeting 2008 - Providence, RI, United States
Duration: Jun 29 2008Jul 2 2008

Other

OtherAmerican Society of Agricultural and Biological Engineers Annual International Meeting 2008
CountryUnited States
CityProvidence, RI
Period6/29/087/2/08

Keywords

  • Biofilter
  • Denitrification
  • Denitrifying enzyme assay
  • Inhibition

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)

Fingerprint Dive into the research topics of 'Characterization of microorganisms contributing to denitrification in tile drain biofilters in illinois'. Together they form a unique fingerprint.

  • Cite this

    Malia Appleford, J., Rodriguez, L. F., Cooke, R. A. C., Zhang, Y., Kent, A. D., & Zilles, J. (2008). Characterization of microorganisms contributing to denitrification in tile drain biofilters in illinois. In American Society of Agricultural and Biological Engineers Annual International Meeting 2008, ASABE 2008 (Vol. 9, pp. 5605-5614). American Society of Agricultural and Biological Engineers.