Denitrification versus respiratory ammonification: environmental controls of two competing dissimilatory NO3(-)/NO2(-) reduction pathways in Shewanella loihica strain PV-4.

ABSTRACT: Denitrification and respiratory ammonification are two competing, energy-conserving NO3(-)/NO2(-) reduction pathways that have major biogeochemical consequences for N retention, plant growth and climate. Batch and continuous culture experiments using Shewanella loihica strain PV-4, a bacterium possessing both the denitrification and respiratory ammonification pathways, revealed factors that determine NO3(-)/NO2(-) fate. Denitrification dominated at low carbon-to-nitrogen (C/N) ratios (that is, electron donor-limiting growth conditions), whereas ammonium was the predominant product at high C/N ratios (that is, electron acceptor-limiting growth conditions). pH and temperature also affected NO3(-)/NO2(-) fate, and incubation above pH 7.0 and temperatures of 30 °C favored ammonium formation. R

SUBMITTER: Yoon S 

PROVIDER: S-EPMC4409154 | biostudies-literature | 2015 May

REPOSITORIES: biostudies-literature