Biooxidation kinetics of Leptospirillum Ferriphilum attached to a defined solid substrate

dc.contributor.advisorPetersen, Jochenen_ZA
dc.contributor.advisorMinnaar, Saneten_ZA
dc.contributor.advisorHarrison, STLen_ZA
dc.contributor.authorDuku, Porogoen_ZA
dc.date.accessioned2014-07-31T11:13:33Z
dc.date.available2014-07-31T11:13:33Z
dc.date.issued2011en_ZA
dc.descriptionIncludes abstract.
dc.descriptionIncludes bibliographical references.
dc.description.abstractBioleaching can be categorized as being either stirred tank type (i.e. bio-oxidation) or irrigation type (i.e. heap/dump bioleaching) yet studies investigating the kinetics of bioleaching systems mostly use empirical data determined from stirred tank type and initial rate experiments in batch cultures or using iso-potential devices. Rate equations deduced from such empirical data is then used to model both the stirred tank type and irrigation type bioleaching systems overlooking the possibility that there may be significant differences in their environments and therefore the kinetics. Tank bioleaching systems are well mixed suspension systems dominated by planktonic microorganisms (freely suspended in the liquid medium). Heap bioleaching systems on the contrary, are heterogeneous in nature with chemical and physical conditions changing over time and are dominated by sessile microorganisms (attached microorganisms to the surface of a solid). The heap bioleaching system is therefore highly complex compared to the stirred tank-type systems. Microbial growth in bioleaching systems significantly influence the overall bioleaching kinetics yet biological kinetic effects in sessile/ attached environments are not well understood. Heap and dump leaching account for about 20% of the world’s copper production and are becoming popular methods of copper production from leaching low grade ores. It is therefore important that the kinetics of irrigation type bioleaching systems are well understood. A strategy to determine the microbial kinetics of a sessile microbial population is enforced in this study. From this, empirical data determined from irrigation type environments can then be used to derive equations which can be used to accurately model heap bioleaching systems. Three sets of experiments were conducted to try and achieve this: i. planktonic experiments - investigating the microbial kinetics of a planktonic microbial population ii. attachment experiments - investigating the nature of growth of the microbial population to the surface of a solid substrate during attachment to create a sessile microbial population iii. sessile experiments - investigating the microbial kinetics of the sessile microbial population A pure culture of Leptospirillum ferriphilum (a mesophilic, ferrous iron oxidizing bioleachingmicroorganism) was used in this study. Planktonic experiments were conducted in a completely mixed, well aerated continuous stirred tank reactor (CSTR) with a 1 litre working volume, operating at a pH of about 1.3 and temperature of 37oC. Attachment and sessile experiments were conducted using a CSTR with similar conditions to the planktonic experimental, however the system was modified by introducing a packed bed vessel (PBR) attached as a closed loop to the CSTR. Solution drawn from the CSTR was then continuously pumped through the PBR and back to the CSTR.en_ZA
dc.identifier.apacitationDuku, P. (2011). <i>Biooxidation kinetics of Leptospirillum Ferriphilum attached to a defined solid substrate</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Chemical Engineering. Retrieved from http://hdl.handle.net/11427/5380en_ZA
dc.identifier.chicagocitationDuku, Porogo. <i>"Biooxidation kinetics of Leptospirillum Ferriphilum attached to a defined solid substrate."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Chemical Engineering, 2011. http://hdl.handle.net/11427/5380en_ZA
dc.identifier.citationDuku, P. 2011. Biooxidation kinetics of Leptospirillum Ferriphilum attached to a defined solid substrate. University of Cape Town.en_ZA
dc.identifier.risTY - Thesis / Dissertation AU - Duku, Porogo AB - Bioleaching can be categorized as being either stirred tank type (i.e. bio-oxidation) or irrigation type (i.e. heap/dump bioleaching) yet studies investigating the kinetics of bioleaching systems mostly use empirical data determined from stirred tank type and initial rate experiments in batch cultures or using iso-potential devices. Rate equations deduced from such empirical data is then used to model both the stirred tank type and irrigation type bioleaching systems overlooking the possibility that there may be significant differences in their environments and therefore the kinetics. Tank bioleaching systems are well mixed suspension systems dominated by planktonic microorganisms (freely suspended in the liquid medium). Heap bioleaching systems on the contrary, are heterogeneous in nature with chemical and physical conditions changing over time and are dominated by sessile microorganisms (attached microorganisms to the surface of a solid). The heap bioleaching system is therefore highly complex compared to the stirred tank-type systems. Microbial growth in bioleaching systems significantly influence the overall bioleaching kinetics yet biological kinetic effects in sessile/ attached environments are not well understood. Heap and dump leaching account for about 20% of the world’s copper production and are becoming popular methods of copper production from leaching low grade ores. It is therefore important that the kinetics of irrigation type bioleaching systems are well understood. A strategy to determine the microbial kinetics of a sessile microbial population is enforced in this study. From this, empirical data determined from irrigation type environments can then be used to derive equations which can be used to accurately model heap bioleaching systems. Three sets of experiments were conducted to try and achieve this: i. planktonic experiments - investigating the microbial kinetics of a planktonic microbial population ii. attachment experiments - investigating the nature of growth of the microbial population to the surface of a solid substrate during attachment to create a sessile microbial population iii. sessile experiments - investigating the microbial kinetics of the sessile microbial population A pure culture of Leptospirillum ferriphilum (a mesophilic, ferrous iron oxidizing bioleachingmicroorganism) was used in this study. Planktonic experiments were conducted in a completely mixed, well aerated continuous stirred tank reactor (CSTR) with a 1 litre working volume, operating at a pH of about 1.3 and temperature of 37oC. Attachment and sessile experiments were conducted using a CSTR with similar conditions to the planktonic experimental, however the system was modified by introducing a packed bed vessel (PBR) attached as a closed loop to the CSTR. Solution drawn from the CSTR was then continuously pumped through the PBR and back to the CSTR. DA - 2011 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2011 T1 - Biooxidation kinetics of Leptospirillum Ferriphilum attached to a defined solid substrate TI - Biooxidation kinetics of Leptospirillum Ferriphilum attached to a defined solid substrate UR - http://hdl.handle.net/11427/5380 ER -en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/5380
dc.identifier.vancouvercitationDuku P. Biooxidation kinetics of Leptospirillum Ferriphilum attached to a defined solid substrate. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Chemical Engineering, 2011 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/5380en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentCentre for Bioprocess Engineering Researchen_ZA
dc.publisher.facultyFaculty of Engineering and the Built Environment
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherBioprocess Engineeringen_ZA
dc.titleBiooxidation kinetics of Leptospirillum Ferriphilum attached to a defined solid substrateen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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