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dc.contributor.authorRamdhani, Nishani
dc.date.accessioned2008-07-16T12:46:59Z
dc.date.available2008-07-16T12:46:59Z
dc.date.issued2005
dc.identifier.otherDIT112619
dc.identifier.urihttp://hdl.handle.net/10321/311
dc.descriptionThesis (M.Tech.: Biotechnology)-Dept. of Biotechnogy, Durban Institute of Technology, 2005 xvi, 85 leaves : ill. ; 31 cmen_US
dc.description.abstractAtmospheric nitrogen pollution is on the increase and human activities are directly or indirectly responsible for the generation of the various nitrogen polluting compounds. This can lead to the two major problems of eutrophication and groundwater pollution. Therefore, the removal of nutrients such as nitrogen and phosphorus from wastewater is important. Nitrogen removal from wastewater is achieved by a combination of nitrification and denitrification. Thus, there is a need to identify and characterise heterotrophic denitrifying bacteria involved in denitrification in wastewater treatment systems. The aim of this study, therefore, was to characterise heterotrophic denitrifying bacteria through detailed biochemical and molecular analysis, to facilitate the understanding of their functional role in wastewater treatment systems. Drysdale (2001) isolated heterotrophic denitrifiers to obtain a culture collection of 179 isolates. This culture collection was used to screen for nitrate and nitrite reduction using the colorimetric biochemical nitrate reduction test. The isolates were thereafter Gram stained to assess their gram reaction, cellular and colonial morphology. Based on these results identical isolates were discarded and a culture collection of approximately 129 isolates remained. The genetic diversity of the culture collection was investigated by the analysis of polymerase chain reaction (PCR)-amplified 16S ribosomal DNA (rDNA) fragments on polyacrylamide gels using denaturing gradient gel electrophoresis (DGGE). Thus DNA fragments of the same length but different nucleotide sequences were effectively separated and microbial community profiles of eight predominant isolates were created. Batch experiments were conducted on these eight isolates, the results of which ultimately confirmed their characterisation and placed them into their four functional groups i.e. 3 isolates were incomplete denitrifiers, 2 isolates were true denitrifiers, 2 isolates were sequential denitrifiers and 1 isolate was an exclusive nitrite reducer.en_US
dc.language.isoenen_US
dc.subjectBiotechnology--Dissertations, Academicen_US
dc.subjectSewage--Purificationen_US
dc.subjectSanitary microbiologyen_US
dc.subjectSewage--Microbiologyen_US
dc.subjectBacteria, denitrifyingen_US
dc.subjectDenitrificationen_US
dc.titleFunctional characterisation of heterotrophic denitrifying bacteria in wastewater treatment systemsen_US
dc.typeThesisen_US
dc.dut-rims.pubnumDUT-000023


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