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dc.contributor.authorPollard, PC
dc.contributor.editorMogens Henze
dc.date.accessioned2017-05-03T13:03:48Z
dc.date.available2017-05-03T13:03:48Z
dc.date.issued2006
dc.date.modified2009-12-09T07:39:29Z
dc.identifier.issn0043-1354
dc.identifier.doi10.1016/j.watres.2006.02.021
dc.identifier.urihttp://hdl.handle.net/10072/11494
dc.description.abstractAbstract: Nitrifying bacteria convert ammonia (NH3) to nitrate (NO3-) in a nitrification reaction. Methods to quantitatively separate the growth rate of these important bacterial populations from that of the dominant heterotrophic bacteria are important to our understanding of the nitrification process. The changing concentration of ammonia is often used as an indirect measure of nitrification but ammonification processes generate ammonia and confound this approach while heterotrophs remove nitrate via denitrification. Molecular probe methods can tell us what proportion of the microbial community is nitrifying bacteria but not their growth rate. The technique proposed here was able to quantify the growth rate of the nitrifying bacterial populations amidst complex ecological processes. The method incubates [methyl-3H] thymidine with water samples in the presence and absence of an inhibitor of nitrification - thiourea. The radioactively labeled DNA in the growing bacteria was extracted. The rate of incorporation of the label into the dividing bacterial DNA was used to determine bacterial growth rate. Total bacterial community growth rates in full-scale and pilot scale fixed-film nitrifying reactors and an activated sludge reactor were 2.1 x 108 cell.mL-1.d-1, 4.1 x 108 cell.mL-1.d-1 and 0.4 x 108 cell.mL-1.d-1 respectively; the growth rate of autotrophic nitrifying bacteria was 0.7 x 108 cell.mL-1.d-1, 2.6 x 108 cell.mL-1.d-1 and 0.01 x 108 cell.mL-1.d-1 respectively. Autotrophic nitrifying bacteria contributed 30 and 60% of the total bacterial community growth rate in the nitrifying reactors whereas only 2% was observed in the activated sludge reactor that was not designed to nitrify. The rates of ammonia loss from the nitrifying reactors corresponded to the rate of growth of the nitrifying bacteria. This method has the potential to more often identify factors that enhance or limit nitrifying processes in both engineered and natural aquatic environments.
dc.description.peerreviewedYes
dc.description.publicationstatusYes
dc.languageEnglish
dc.language.isoeng
dc.publisherPergamon Press
dc.publisher.placeOxford, UK
dc.publisher.urihttp://www.sciencedirect.com/science/journal/00431354
dc.relation.ispartofstudentpublicationN
dc.relation.ispartofpagefrom1569
dc.relation.ispartofpageto1576
dc.relation.ispartofedition2006
dc.relation.ispartofjournalWater Research
dc.relation.ispartofvolume40
dc.rights.retentionY
dc.subject.fieldofresearchcode270307
dc.titleA quantitative measure of nitrifying bacterial growth
dc.typeJournal article
dc.type.descriptionC1 - Articles
dc.type.codeC - Journal Articles
gro.facultyGriffith Sciences, Griffith School of Environment
gro.date.issued2006
gro.hasfulltextNo Full Text
gro.griffith.authorPollard, Peter C.


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