Access to digitised archival collections in National Heritage and Cultural study Centre and International Library of African Music
- Authors: Barbra, Kakumba
- Date: 2021-04
- Subjects: Archives -- Access control , Archival materials -- Access control
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22356 , vital:52030
- Description: The study investigated access to digitised archival collections in two selected institutions in the Eastern Cape Province, South Africa. This study is significant because it sought to generate insights on adaptability of technology in archives and library operations, and accessibility thereof. This is important for monitoring the accessibility of digitised archival collections at institutions to improve their operations and maximize the global visibility. This study adopted qualitative research methodology. The researcher followed a rigorous methodological path that began with a thorough literature review and the careful and thoughtful posing of research questions and objectives. A purposive sample was chosen from National Heritage and Cultural Studies Centre (NAHECS) and International library of African Music (ILAM) (staff members) and interviewed through face-to-face interviews. The collected data was analysed thematically. The study established that, the type of materials digitised at NAHECS and ILAM are bound books, fragile papers, photographic prints, slides, audio-visual materials,artefacts and documents such as personal letters of early travellers,missionary’s records,traders writing personal file and political parties documents. Secondly, the study established that end users of digitised materials are researchers, students, archivist, librarians, international and local community, composers, musicians, and historians. It also emerged that awareness programmes used to increase public knowledge about access to digitised content in the two study sites include conferences, social media, and television advertisements. However, there are challenges faced in providing access to digitised materials at NAHECS and ILAM. Some of these challenges include lack of funding, unavailability of resources, lack of awareness, and information insecurity. These challenges have made access to digitised archival materials difficult. Based on these findings, it is recommended that archives facilities should be well resourced and archivists be continually trained on access to digitised archival materials. , Thesis (M Bibl) -- Faculty of Social Sciences and Humanities, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Barbra, Kakumba
- Date: 2021-04
- Subjects: Archives -- Access control , Archival materials -- Access control
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22356 , vital:52030
- Description: The study investigated access to digitised archival collections in two selected institutions in the Eastern Cape Province, South Africa. This study is significant because it sought to generate insights on adaptability of technology in archives and library operations, and accessibility thereof. This is important for monitoring the accessibility of digitised archival collections at institutions to improve their operations and maximize the global visibility. This study adopted qualitative research methodology. The researcher followed a rigorous methodological path that began with a thorough literature review and the careful and thoughtful posing of research questions and objectives. A purposive sample was chosen from National Heritage and Cultural Studies Centre (NAHECS) and International library of African Music (ILAM) (staff members) and interviewed through face-to-face interviews. The collected data was analysed thematically. The study established that, the type of materials digitised at NAHECS and ILAM are bound books, fragile papers, photographic prints, slides, audio-visual materials,artefacts and documents such as personal letters of early travellers,missionary’s records,traders writing personal file and political parties documents. Secondly, the study established that end users of digitised materials are researchers, students, archivist, librarians, international and local community, composers, musicians, and historians. It also emerged that awareness programmes used to increase public knowledge about access to digitised content in the two study sites include conferences, social media, and television advertisements. However, there are challenges faced in providing access to digitised materials at NAHECS and ILAM. Some of these challenges include lack of funding, unavailability of resources, lack of awareness, and information insecurity. These challenges have made access to digitised archival materials difficult. Based on these findings, it is recommended that archives facilities should be well resourced and archivists be continually trained on access to digitised archival materials. , Thesis (M Bibl) -- Faculty of Social Sciences and Humanities, 2021
- Full Text:
- Date Issued: 2021-04
Poppehysie
- Authors: Arendse, Ashwin Albert
- Date: 2021-04
- Subjects: Kaaps , Creative writing (Higher education) -- South Africa , Diaries -- Authorship , Afrikaans poetry -- 21st century , African literature -- History and criticism
- Language: Afrikaans
- Type: thesis , text , Masters , MA
- Identifier: http://hdl.handle.net/10962/178259 , vital:42925
- Description: My thesis, is geskryf in Swartlandse Kaaps, ’n streeksvariant van Kaaps. Die poems is free verses wat afspeel tien ie backdrop van Malmesbury en Stellenbosch se “Coloured areas” mette analysis van dialect en ideolect wat eie is annie mense wat ampe altyd feature innie stories wat ek vertel. Die thesis explore die liefde asse konsep. Dit kyk na hoe die desperate need vi absent liefde ’n toxic relationship feed tussen ’n jong couple ennie destructive impact van liefde oppe pesoon wie nooit geleer was hoe om lief te wies vi annes ie. Dan kyk ek oek na hoe die previous generations, dit van my ma en pa liefde reject et asse unaffordable excess inne community wat brutal en harsh is. Antonio Gramsci se konsep vannie organic intellectual, dien asse philosophical underpinning virrie thesis d.w.s die hoofkarakter dien asse orator virrie intellectual en cultural insights wattie everyman in sy community nie self kan express ie. Die organic intellectual express díe thoughts innie cultural taal van sy social class. Die thesis explore stories soes it vetel wôd dee mense soes my oupa en mense wattie altyd aware is dat hulle stories in hulle in hettie. In dai way val it tot some degree binne die terrain van oral traditions. Die thesis wil dip into die collective conscious vanne social group wat die worst aspects van liewe in Syd-Afrika experience et. Ek voel free verse is ie ideal form van expression vi my in regards tot die skryf van die thesis, omdat ek daamee die line successfully kan blur tussen ie ‘language of the people’ en my eie individual leaning toward poetic language en forms. In terms van style draw ek op vorige digbundels in Kaaps, most notably op Nathan Trantraal se baie controlled, free verse digbundel, ‘Alles het niet kom wôd,’en Ronelda S. Kamfer se technique van ‘oorvertel’, in haa digbundel ‘grond/Santekraam’. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Arendse, Ashwin Albert
- Date: 2021-04
- Subjects: Kaaps , Creative writing (Higher education) -- South Africa , Diaries -- Authorship , Afrikaans poetry -- 21st century , African literature -- History and criticism
- Language: Afrikaans
- Type: thesis , text , Masters , MA
- Identifier: http://hdl.handle.net/10962/178259 , vital:42925
- Description: My thesis, is geskryf in Swartlandse Kaaps, ’n streeksvariant van Kaaps. Die poems is free verses wat afspeel tien ie backdrop van Malmesbury en Stellenbosch se “Coloured areas” mette analysis van dialect en ideolect wat eie is annie mense wat ampe altyd feature innie stories wat ek vertel. Die thesis explore die liefde asse konsep. Dit kyk na hoe die desperate need vi absent liefde ’n toxic relationship feed tussen ’n jong couple ennie destructive impact van liefde oppe pesoon wie nooit geleer was hoe om lief te wies vi annes ie. Dan kyk ek oek na hoe die previous generations, dit van my ma en pa liefde reject et asse unaffordable excess inne community wat brutal en harsh is. Antonio Gramsci se konsep vannie organic intellectual, dien asse philosophical underpinning virrie thesis d.w.s die hoofkarakter dien asse orator virrie intellectual en cultural insights wattie everyman in sy community nie self kan express ie. Die organic intellectual express díe thoughts innie cultural taal van sy social class. Die thesis explore stories soes it vetel wôd dee mense soes my oupa en mense wattie altyd aware is dat hulle stories in hulle in hettie. In dai way val it tot some degree binne die terrain van oral traditions. Die thesis wil dip into die collective conscious vanne social group wat die worst aspects van liewe in Syd-Afrika experience et. Ek voel free verse is ie ideal form van expression vi my in regards tot die skryf van die thesis, omdat ek daamee die line successfully kan blur tussen ie ‘language of the people’ en my eie individual leaning toward poetic language en forms. In terms van style draw ek op vorige digbundels in Kaaps, most notably op Nathan Trantraal se baie controlled, free verse digbundel, ‘Alles het niet kom wôd,’en Ronelda S. Kamfer se technique van ‘oorvertel’, in haa digbundel ‘grond/Santekraam’. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
- Full Text:
- Date Issued: 2021-04
Mapping the pyrroloiminoquinone diversity produced by latrunculid sponges using tandem mass spectrometry-driven molecular networking
- Authors: Kalinski, Jarmo-Charles J
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178468 , vital:42942
- Description: Access restricted until April 2023. , Thesis (PhD) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Kalinski, Jarmo-Charles J
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178468 , vital:42942
- Description: Access restricted until April 2023. , Thesis (PhD) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-04
The impact of bank concentration on bank stability: evidence from the South African Banking Sector
- Magaga, Zizipo https://orcid.org/0000-0001-7008-1908
- Authors: Magaga, Zizipo https://orcid.org/0000-0001-7008-1908
- Date: 2021-04
- Subjects: Banks and banking, Central -- South Africa , Capital market -- South Africa , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/29462 , vital:77969
- Description: Motivated by the debate on the concentration-stability nexus, this study investigated the impact of bank concentration on bank stability in South Africa. The study used yearly panel data for the period 2000 to 2021. The fixed and random effects and the Hausman test to choose the best model were used. Based on the results of the Hausman test, the random effects model was appropriate for this study whereby all the banks in question have random intercepts that vary as time changes. The results also reveal that all the relationships were statistically significant. In addition, the results lead to the conclusion that bank concentration and interest rate negatively impact bank stability. However, bank size and liquidity showed positive impact on bank stability. The study recommends policy makers to establish regulations that restrict excessive risk taking in the banking sector. Also, policy makers should put policies that favour an environment where banks can easily obtain funds through capital markets as this will encourage their growth thereby resulting in banking sector stability. , Thesis (MCom (Economics)) -- Faculty of Management and Commerce, 2023
- Full Text:
- Date Issued: 2021-04
- Authors: Magaga, Zizipo https://orcid.org/0000-0001-7008-1908
- Date: 2021-04
- Subjects: Banks and banking, Central -- South Africa , Capital market -- South Africa , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/29462 , vital:77969
- Description: Motivated by the debate on the concentration-stability nexus, this study investigated the impact of bank concentration on bank stability in South Africa. The study used yearly panel data for the period 2000 to 2021. The fixed and random effects and the Hausman test to choose the best model were used. Based on the results of the Hausman test, the random effects model was appropriate for this study whereby all the banks in question have random intercepts that vary as time changes. The results also reveal that all the relationships were statistically significant. In addition, the results lead to the conclusion that bank concentration and interest rate negatively impact bank stability. However, bank size and liquidity showed positive impact on bank stability. The study recommends policy makers to establish regulations that restrict excessive risk taking in the banking sector. Also, policy makers should put policies that favour an environment where banks can easily obtain funds through capital markets as this will encourage their growth thereby resulting in banking sector stability. , Thesis (MCom (Economics)) -- Faculty of Management and Commerce, 2023
- Full Text:
- Date Issued: 2021-04
The application of the doctrine of common purpose to the joint possession of firearms
- Authors: Mnono, Zimbini
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Firearms--Law and legislation
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/51197 , vital:43225
- Description: According to the South African criminal justice system, where two or more people in a joint unlawful enterprise associate to commit a crime with only one participant carrying a firearm, the principles of joint possession are used to secure successful prosecution of the participants for joint possession of the firearm. However, up to date, the State is yet to see a conviction based on the application of these principles. S v Khambule marks the first case in which the doctrine of common purpose was used to secure a conviction of multiple accused for the crime of joint possession of firearms. The case has become outdated law following the Supreme Court of Appeal decision in S v Mbuli where the court found that the doctrine could not be applied to circumstance crimes such as joint possession of firearms. Both cases have received enormous criticism from academics and in subsequent judgments. One main criticism relates to whether the failure to apply the doctrine of common purpose is consistent with the current law and constitutional freedoms, such as the right to be free from all forms of violence and the right to equal benefit of the law. The purpose of the dissertation is to evaluate the jurisprudence on the application of the doctrine of common purpose to the joint possession of firearms. The evaluation includes an analysis of the principles of joint possession in the context of constitutional rights as well as contributions made by academics such as Burchell. The commonpurpose doctrine does not extend to joint possession of firearms. This is as a result of firstly, the absence of causation from the definitional elements of the crime; secondly, the mental aspect of possession; thirdly, the principles of joint possession as the basis of liability for joint possession of firearms; and lastly due to the nature of the crime of joint possession of firearms, being a circumstance crime. The paper recommends the extension of the doctrine of common purpose to joint possession of firearms. The recommendation is based on the following arguments. Firstly, the mental aspect of possession relates to the description of the article and not fault. Secondly, the doctrine is and has always been intended to criminalise joint wrongdoings. Thirdly, the extension of the doctrine of common purpose to joint possession of firearms is consistent with the presumption of possession in terms of the Firearm Controls Act. Lastly, the expansion enhances constitutional rights and fulfils the duty of the State to make South Africa less vulnerable to firearms. , Thesis (LLM) -- Faculty of Law, Criminal and Procedural Law, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Mnono, Zimbini
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Firearms--Law and legislation
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/51197 , vital:43225
- Description: According to the South African criminal justice system, where two or more people in a joint unlawful enterprise associate to commit a crime with only one participant carrying a firearm, the principles of joint possession are used to secure successful prosecution of the participants for joint possession of the firearm. However, up to date, the State is yet to see a conviction based on the application of these principles. S v Khambule marks the first case in which the doctrine of common purpose was used to secure a conviction of multiple accused for the crime of joint possession of firearms. The case has become outdated law following the Supreme Court of Appeal decision in S v Mbuli where the court found that the doctrine could not be applied to circumstance crimes such as joint possession of firearms. Both cases have received enormous criticism from academics and in subsequent judgments. One main criticism relates to whether the failure to apply the doctrine of common purpose is consistent with the current law and constitutional freedoms, such as the right to be free from all forms of violence and the right to equal benefit of the law. The purpose of the dissertation is to evaluate the jurisprudence on the application of the doctrine of common purpose to the joint possession of firearms. The evaluation includes an analysis of the principles of joint possession in the context of constitutional rights as well as contributions made by academics such as Burchell. The commonpurpose doctrine does not extend to joint possession of firearms. This is as a result of firstly, the absence of causation from the definitional elements of the crime; secondly, the mental aspect of possession; thirdly, the principles of joint possession as the basis of liability for joint possession of firearms; and lastly due to the nature of the crime of joint possession of firearms, being a circumstance crime. The paper recommends the extension of the doctrine of common purpose to joint possession of firearms. The recommendation is based on the following arguments. Firstly, the mental aspect of possession relates to the description of the article and not fault. Secondly, the doctrine is and has always been intended to criminalise joint wrongdoings. Thirdly, the extension of the doctrine of common purpose to joint possession of firearms is consistent with the presumption of possession in terms of the Firearm Controls Act. Lastly, the expansion enhances constitutional rights and fulfils the duty of the State to make South Africa less vulnerable to firearms. , Thesis (LLM) -- Faculty of Law, Criminal and Procedural Law, 2021
- Full Text:
- Date Issued: 2021-04
The effect of various substrate pretreatment methods on the enzymatic degradability of a Eucalyptus sp. – a potential feedstock for producing fermentable sugars
- Authors: Thoresen, Mariska
- Date: 2021-04
- Subjects: Cellulose , Cellulase , Enzymes , Hydrolysis , Eucalyptus , Biomass energy
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178580 , vital:42952 , DOI 10.21504/10962/178580
- Description: Over the past few years, there has been a global urgency to make the transition from conventional fossil fuels to renewable energy in order to meet the world’s increasing energy demands. Lignocellulosic biomass is currently at the forefront of intensive biofuel research due to its renewable nature. Lignocellulose valorisation into value added products such as bio-ethanol is a multistep process. The first step requires the biomass to go through a recalcitrance-reducing step (pretreatment), after which, enzymatic hydrolysis is required to break down the polysaccharides into simple sugars for fermentation. However, the recalcitrant structure of biomass and the low hydrolytic activities of the enzymes (glycoside hydrolases) on the substrate pose major technical and economic obstacles to the biomass conversion process. Since this process remains more expensive compared to petroleum-based fuels, lignocellulose has been intensively investigated in terms of its cost efficiency and effective decomposition. Although improvements to this process are ongoing, with some of the first commercial facilities producing cellulosic ethanol in 2013 and 2014, there is still a deep sense of urgency to render the facilities more economically feasible. Some important factors that determine the yield and rate of enzymatic hydrolysis include the type of enzymes used, enzyme recognition with the substrate, substrate composition and crystallinity. In this context, the major focus of this study was to develop a deeper understanding of how enzymes co-operate (synergise) at a molecular level using model substrates. This knowledge was then used as a basis for understanding how these enzymes synergise on more natural, complex substrates. This study specifically focused on how different pretreatments affect the chemical and structural properties of Eucalyptus. Lastly, we wanted to develop an effective method of enzyme recycling as a means to reduce the high process costs in biomass saccharification. Enhancing cellulose hydrolysis through enzyme synergy is essential for achieving higher hydrolysis rates, and numerous research efforts have focused on trying to elucidate the enzyme mechanisms required to design optimal enzyme cocktails. Despite the extensive amount of research carried out over the past few years, little is known about the enzymatic machinery underpinning the synergistic interactions between bacterial and fungal cellulases - neither is it understood why only a limited number of Cellobiohydrolases (CBHs) and Endoglucanases (EGs) exhibit synergism. Therefore, the first part of the study evaluated and compared the synergistic relationships between cellulases from different GH families and microbial sources (cross-synergism), i.e. cellobiohydrolase I (CBHI) from Hypocrea jecorina (Cel7A), CBHI from Trichoderma longibrachiatum (Cel7A), CBHI from Clostridium stercorarium (Cel48A), CBHII from a microbial source, CBHII from Clostridium thermocellum (Cel5A), endoglucanases (EG) from Bacillus amyloliquefaciens (Cel5A), EG from Thermotaga maritima (Cel5A), EG from Trichoderma reesei and a β-glucosidase from Aspergillus niger (Novozyme 188). An aim of this study was to provide insights into how the molecular mechanisms of different GH families govern synergism. The results showed that cellulases from different GH families and microbial sources exhibit different substrate specificities, which influence their synergistic interactions with other enzymes. Based on these observations, this study agreed with evidence that not all endo- and exo-cellulase interactions are synergistic, and that the extent of synergism is dependent on the composition of the cellulase systems from various sources and their compatibility in the cellulase cocktail. From the enzymes assessed in this study, an optimal enzyme cocktail (CelMix) was formulated which was composed of Egl 68%, Cel7A 17%, Cel6A 6%, βgl 9%. This method of screening for maximal compatibility between exo- and endo-cellulases from different GH families constituted a critical step towards a better understanding of the specific interactions between the enzymes of interest and how they synergise at the molecular level. Consequently, this information may assist in the design of improved synergistic cellulose-degrading cocktails for industrial-scale biomass degradation. The enzyme synergy studies provided a basis for the second part of this study, where it was assessed how these optimised enzyme cocktails would perform on complex substrates. It is well-known that lignocellulosic substrates are highly recalcitrant to microbial degradation, and although extensive research has been performed to understand biomass recalcitrance, the key features of biomass which hinder enzymatic hydrolysis are yet to be elucidated. In this study, we explored the effect of eight (8) different pretreatment methods on the enzymatic hydrolysis of a Eucalyptus sp. – a potential feedstock for biofuel production. This study was performed to increase our understanding of the relationship between biomass architecture and hydrolysis yield potential. Our results demonstrated that pretreatments induce changes at a micro- and macro-level in the cell walls of Eucalyptus, and that cellulose accessibility, cellulose crystallinity and the changes in the lignin S/G ratio played an important role in the enzymatic activity on the biomass. Thus, this study provided insight into important cellulose structural features related to biomass recalcitrance arising from various pretreatment methods, which may ultimately be used for the development of more efficient conversion technologies for better, more competitive bio-refineries. Lastly, a simple and yet effective method for desorbing the adsorbed cellulases on lignocellulosic substrates was established for better understanding cellulase adsorption and desorption in order to develop an effective enzyme recycling strategy. Various reagents were assessed to determine how effective they were in promoting enzyme desorption. Tris-HCl buffer (pH 9.0; 0.05 M) was the most effective method for promoting enzyme desorption and retained a substantial amount of hydrolytic activity after elution. However, minor activity loss was observed due to irreversible binding, which was further confirmed by SDS-PAGE analysis. With this information available, the feasibility of recovering the enzymes from the solid fraction after enzymatic hydrolysis of steam pretreated Eucalyptus was evaluated by two different approaches, i.e.: i) re-adsorption of the entire hydrolysed insoluble biomass fraction (no desorption) to fresh biomass (recycling approach 1 - RA1) and ii) re-adsorption of alkaline elution desorbed enzymes from hydrolysed biomass to fresh biomass (recycling approach 2 - RA2). The recycling performance of RA1 and RA2 achieved > 95% of the initial sugar liberation for three continuous rounds, whilst successfully reducing enzyme loadings by 50% and 40% for RA1 and RA2, respectively. This study presented a simple and effective pathway for improving the economic feasibility of fermentable sugar production for biofuels. In conclusion, this study has contributed to expanding our knowledge and providing new insights into factors relating to the biomass conversion process, including enzyme synergism, pretreatment methods and enzyme recycling strategies. Ultimately, the knowledge and information gained from this study can be used as a platform for the development of more efficient conversion technologies for better, more competitive bio-refineries. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Thoresen, Mariska
- Date: 2021-04
- Subjects: Cellulose , Cellulase , Enzymes , Hydrolysis , Eucalyptus , Biomass energy
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178580 , vital:42952 , DOI 10.21504/10962/178580
- Description: Over the past few years, there has been a global urgency to make the transition from conventional fossil fuels to renewable energy in order to meet the world’s increasing energy demands. Lignocellulosic biomass is currently at the forefront of intensive biofuel research due to its renewable nature. Lignocellulose valorisation into value added products such as bio-ethanol is a multistep process. The first step requires the biomass to go through a recalcitrance-reducing step (pretreatment), after which, enzymatic hydrolysis is required to break down the polysaccharides into simple sugars for fermentation. However, the recalcitrant structure of biomass and the low hydrolytic activities of the enzymes (glycoside hydrolases) on the substrate pose major technical and economic obstacles to the biomass conversion process. Since this process remains more expensive compared to petroleum-based fuels, lignocellulose has been intensively investigated in terms of its cost efficiency and effective decomposition. Although improvements to this process are ongoing, with some of the first commercial facilities producing cellulosic ethanol in 2013 and 2014, there is still a deep sense of urgency to render the facilities more economically feasible. Some important factors that determine the yield and rate of enzymatic hydrolysis include the type of enzymes used, enzyme recognition with the substrate, substrate composition and crystallinity. In this context, the major focus of this study was to develop a deeper understanding of how enzymes co-operate (synergise) at a molecular level using model substrates. This knowledge was then used as a basis for understanding how these enzymes synergise on more natural, complex substrates. This study specifically focused on how different pretreatments affect the chemical and structural properties of Eucalyptus. Lastly, we wanted to develop an effective method of enzyme recycling as a means to reduce the high process costs in biomass saccharification. Enhancing cellulose hydrolysis through enzyme synergy is essential for achieving higher hydrolysis rates, and numerous research efforts have focused on trying to elucidate the enzyme mechanisms required to design optimal enzyme cocktails. Despite the extensive amount of research carried out over the past few years, little is known about the enzymatic machinery underpinning the synergistic interactions between bacterial and fungal cellulases - neither is it understood why only a limited number of Cellobiohydrolases (CBHs) and Endoglucanases (EGs) exhibit synergism. Therefore, the first part of the study evaluated and compared the synergistic relationships between cellulases from different GH families and microbial sources (cross-synergism), i.e. cellobiohydrolase I (CBHI) from Hypocrea jecorina (Cel7A), CBHI from Trichoderma longibrachiatum (Cel7A), CBHI from Clostridium stercorarium (Cel48A), CBHII from a microbial source, CBHII from Clostridium thermocellum (Cel5A), endoglucanases (EG) from Bacillus amyloliquefaciens (Cel5A), EG from Thermotaga maritima (Cel5A), EG from Trichoderma reesei and a β-glucosidase from Aspergillus niger (Novozyme 188). An aim of this study was to provide insights into how the molecular mechanisms of different GH families govern synergism. The results showed that cellulases from different GH families and microbial sources exhibit different substrate specificities, which influence their synergistic interactions with other enzymes. Based on these observations, this study agreed with evidence that not all endo- and exo-cellulase interactions are synergistic, and that the extent of synergism is dependent on the composition of the cellulase systems from various sources and their compatibility in the cellulase cocktail. From the enzymes assessed in this study, an optimal enzyme cocktail (CelMix) was formulated which was composed of Egl 68%, Cel7A 17%, Cel6A 6%, βgl 9%. This method of screening for maximal compatibility between exo- and endo-cellulases from different GH families constituted a critical step towards a better understanding of the specific interactions between the enzymes of interest and how they synergise at the molecular level. Consequently, this information may assist in the design of improved synergistic cellulose-degrading cocktails for industrial-scale biomass degradation. The enzyme synergy studies provided a basis for the second part of this study, where it was assessed how these optimised enzyme cocktails would perform on complex substrates. It is well-known that lignocellulosic substrates are highly recalcitrant to microbial degradation, and although extensive research has been performed to understand biomass recalcitrance, the key features of biomass which hinder enzymatic hydrolysis are yet to be elucidated. In this study, we explored the effect of eight (8) different pretreatment methods on the enzymatic hydrolysis of a Eucalyptus sp. – a potential feedstock for biofuel production. This study was performed to increase our understanding of the relationship between biomass architecture and hydrolysis yield potential. Our results demonstrated that pretreatments induce changes at a micro- and macro-level in the cell walls of Eucalyptus, and that cellulose accessibility, cellulose crystallinity and the changes in the lignin S/G ratio played an important role in the enzymatic activity on the biomass. Thus, this study provided insight into important cellulose structural features related to biomass recalcitrance arising from various pretreatment methods, which may ultimately be used for the development of more efficient conversion technologies for better, more competitive bio-refineries. Lastly, a simple and yet effective method for desorbing the adsorbed cellulases on lignocellulosic substrates was established for better understanding cellulase adsorption and desorption in order to develop an effective enzyme recycling strategy. Various reagents were assessed to determine how effective they were in promoting enzyme desorption. Tris-HCl buffer (pH 9.0; 0.05 M) was the most effective method for promoting enzyme desorption and retained a substantial amount of hydrolytic activity after elution. However, minor activity loss was observed due to irreversible binding, which was further confirmed by SDS-PAGE analysis. With this information available, the feasibility of recovering the enzymes from the solid fraction after enzymatic hydrolysis of steam pretreated Eucalyptus was evaluated by two different approaches, i.e.: i) re-adsorption of the entire hydrolysed insoluble biomass fraction (no desorption) to fresh biomass (recycling approach 1 - RA1) and ii) re-adsorption of alkaline elution desorbed enzymes from hydrolysed biomass to fresh biomass (recycling approach 2 - RA2). The recycling performance of RA1 and RA2 achieved > 95% of the initial sugar liberation for three continuous rounds, whilst successfully reducing enzyme loadings by 50% and 40% for RA1 and RA2, respectively. This study presented a simple and effective pathway for improving the economic feasibility of fermentable sugar production for biofuels. In conclusion, this study has contributed to expanding our knowledge and providing new insights into factors relating to the biomass conversion process, including enzyme synergism, pretreatment methods and enzyme recycling strategies. Ultimately, the knowledge and information gained from this study can be used as a platform for the development of more efficient conversion technologies for better, more competitive bio-refineries. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-04
Anisotropic copper oxide nanorods decorated with gold and palladium nanoparticles and their enzymatic properties
- Authors: Sicwetsha, Simbongile
- Date: 2021-04
- Subjects: Nanoparticles , Artificial enzyme , Copper oxide , Peroxidase activity
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178547 , vital:42949
- Description: The synthesis of spherical CuO nanoparticles (CuONPs), copper oxide nanorods (CuONRs), CuONRs decorated with gold (CuONRs@Au1.0NPs), CuONRs decorated with palladium (CuONRs@Pd1.0NPs) and CuONRs decorated with gold and palladium (CuONRs@Au0.5/Pd 0.5NPs) was carried out. The successful preparation of these nanomaterials was confirmed using UV-vis, DLS (zeta potential), XRD, TEM and EDS. The nanoparticles were found to possess intrinsic peroxidase-like activity. The peroxidase-like activity of the nanoparticles was dependent on pH, temperature and enzyme substrate concentration. The investigation of the steady-state kinetic parameters showed that the peroxidase-like activity of the nanomaterials followed the Michaelis-Menten kinetics behaviour. The spherical CuONPs showed the Km = 1.12 mM and 1.14 mM for H2O2 and TMB respectively. The CuONRs showed the Km = 40.04 mM and 2.91 mM for H2O2 and TMB respectively. The CuONRs@Au1.0NPs showed the Km = 3.05 mM and 6.49 mM for H2O2 and TMB respectively. The CuONRs@Pd1.0NPs showed the Km = 0.13 mM and 2.59 mM for H2O2 and TMB respectively. The CuONRs@Au0.5/Pd0.5NPs showed the Km = 2.66 mM and Km = 19.70 mM for H2O2 and TMB respectively. The nanomaterials interact with hydrogen peroxide to produce hydroxyl radicals (OH·). Therefore, the production of reactive oxygen species (ROS) was investigated and detected using 1,3-diphenylisobenzofuran (DPBF) as a radical scavenger. The prepared nanomaterials were used in biosensing for the colorimetric detection of glucose. The LOD and LOQ for spherical CuONPs was 0.73 μM and 2.42 μM, for CuONRs was 0.13 μM and 0.42 μM, CuONRs@Au1.0NPs was 7.19 μM and 21.78 μM, for CuONRs@Pd1.0 NPs was 19.65 μM and 59.54 μM, and for CuONRs@Au0.5/Pd0.5NPs was 10.46 μM and 31.71 μM. , Thesis (MSc) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Sicwetsha, Simbongile
- Date: 2021-04
- Subjects: Nanoparticles , Artificial enzyme , Copper oxide , Peroxidase activity
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178547 , vital:42949
- Description: The synthesis of spherical CuO nanoparticles (CuONPs), copper oxide nanorods (CuONRs), CuONRs decorated with gold (CuONRs@Au1.0NPs), CuONRs decorated with palladium (CuONRs@Pd1.0NPs) and CuONRs decorated with gold and palladium (CuONRs@Au0.5/Pd 0.5NPs) was carried out. The successful preparation of these nanomaterials was confirmed using UV-vis, DLS (zeta potential), XRD, TEM and EDS. The nanoparticles were found to possess intrinsic peroxidase-like activity. The peroxidase-like activity of the nanoparticles was dependent on pH, temperature and enzyme substrate concentration. The investigation of the steady-state kinetic parameters showed that the peroxidase-like activity of the nanomaterials followed the Michaelis-Menten kinetics behaviour. The spherical CuONPs showed the Km = 1.12 mM and 1.14 mM for H2O2 and TMB respectively. The CuONRs showed the Km = 40.04 mM and 2.91 mM for H2O2 and TMB respectively. The CuONRs@Au1.0NPs showed the Km = 3.05 mM and 6.49 mM for H2O2 and TMB respectively. The CuONRs@Pd1.0NPs showed the Km = 0.13 mM and 2.59 mM for H2O2 and TMB respectively. The CuONRs@Au0.5/Pd0.5NPs showed the Km = 2.66 mM and Km = 19.70 mM for H2O2 and TMB respectively. The nanomaterials interact with hydrogen peroxide to produce hydroxyl radicals (OH·). Therefore, the production of reactive oxygen species (ROS) was investigated and detected using 1,3-diphenylisobenzofuran (DPBF) as a radical scavenger. The prepared nanomaterials were used in biosensing for the colorimetric detection of glucose. The LOD and LOQ for spherical CuONPs was 0.73 μM and 2.42 μM, for CuONRs was 0.13 μM and 0.42 μM, CuONRs@Au1.0NPs was 7.19 μM and 21.78 μM, for CuONRs@Pd1.0 NPs was 19.65 μM and 59.54 μM, and for CuONRs@Au0.5/Pd0.5NPs was 10.46 μM and 31.71 μM. , Thesis (MSc) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-04
Pedagogic videos as a foreign language learning resource in textbooks used in the German studies section of a South African university: A digital multimodal discourse perspective
- Authors: Schafli, Sasha-Lee
- Date: 2021-04
- Subjects: Language and languages Study and teaching Audio-visual aids , Educational technology , Media programs (Education) , German language Study and teaching Foreign speakers Audio-visual aids , Visual learning , Rhodes University , German language Discourse analysis , Digital multimodal discourse analysis
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/177087 , vital:42789 , http://doi.org/10.21504/10962/177087
- Description: Video is a prominent teaching and learning tool within foreign language (FL) textbook media packages in the 21st century. While studies undertaken in the Global North highlight that video materials in the FL classroom have the potential to influence learning and cultural knowledge acquisition, there is a lack of research on the manner in which pedagogically designed videos influence adult FL learning and cultural knowledge acquisition in a South African context. In this study, I explore the opportunities and challenges in terms of language learning and cultural knowledge acquisition that arise from three pedagogic videos in the Menschen A1 textbook which is used in teaching students registered for the German Studies 1 course at Rhodes University. I compare and contrast two sets of data to examine the relationship between pedagogic video and student knowledge acquisition: the results of a digital multimodal discourse analysis (DMDA) of these videos, and questionnaires and transcriptions collected from semi-structured group interviews with German Studies 1 students. These questionnaires and transcriptions were analysed thematically. Findings in terms of the language learning experience indicate that actor over-exaggeration and visual aids assist students when learning German at this level with this type of video. However, these visual aids can be distracting and confusing without balanced representation and contextual information. Differences between videos in terms of speech rate seem to affect students’ perceptions of their ability to comprehend the videos. Students reported forming only positive impressions of German culture(s) on the basis of the videos. In general, students find Germans portrayed as friendly and helpful in the videos. The results of this investigation provide recommendations for the optimal use of this type of teaching and learning resource, for example, teachers/ lecturers/ facilitators should allow for focus group discussions on cultural discourse to occur in order to balance stereotype formation and should consider the speech rate of videos for language learning. , Thesis (MA) -- Faculty of Humanities, Linguistics and Applied Language Studies, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Schafli, Sasha-Lee
- Date: 2021-04
- Subjects: Language and languages Study and teaching Audio-visual aids , Educational technology , Media programs (Education) , German language Study and teaching Foreign speakers Audio-visual aids , Visual learning , Rhodes University , German language Discourse analysis , Digital multimodal discourse analysis
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/177087 , vital:42789 , http://doi.org/10.21504/10962/177087
- Description: Video is a prominent teaching and learning tool within foreign language (FL) textbook media packages in the 21st century. While studies undertaken in the Global North highlight that video materials in the FL classroom have the potential to influence learning and cultural knowledge acquisition, there is a lack of research on the manner in which pedagogically designed videos influence adult FL learning and cultural knowledge acquisition in a South African context. In this study, I explore the opportunities and challenges in terms of language learning and cultural knowledge acquisition that arise from three pedagogic videos in the Menschen A1 textbook which is used in teaching students registered for the German Studies 1 course at Rhodes University. I compare and contrast two sets of data to examine the relationship between pedagogic video and student knowledge acquisition: the results of a digital multimodal discourse analysis (DMDA) of these videos, and questionnaires and transcriptions collected from semi-structured group interviews with German Studies 1 students. These questionnaires and transcriptions were analysed thematically. Findings in terms of the language learning experience indicate that actor over-exaggeration and visual aids assist students when learning German at this level with this type of video. However, these visual aids can be distracting and confusing without balanced representation and contextual information. Differences between videos in terms of speech rate seem to affect students’ perceptions of their ability to comprehend the videos. Students reported forming only positive impressions of German culture(s) on the basis of the videos. In general, students find Germans portrayed as friendly and helpful in the videos. The results of this investigation provide recommendations for the optimal use of this type of teaching and learning resource, for example, teachers/ lecturers/ facilitators should allow for focus group discussions on cultural discourse to occur in order to balance stereotype formation and should consider the speech rate of videos for language learning. , Thesis (MA) -- Faculty of Humanities, Linguistics and Applied Language Studies, 2021
- Full Text:
- Date Issued: 2021-04
Evaluation of water quality, selected metals and endocrine-disrupting compounds in the rivers and municipal wastewaters of Eastern Cape province, South Africa
- Authors: Farounbi, Adebayo Ibikunle
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177327 , vital:42810 , DOI 10.21504/10962/177327
- Description: South Africa is developing with increasing population, and so is the demand for use and access to water resources. Surface water is critical to the country because it provides about 77% of the needed water resources. Low rainfall (about 450 mm annually) with little runoffs to boost the rivers aggravates the problems of surface waters. Expansion of industrial and agricultural activities coupled with the population pressure had an impact on water quality, availability and the state of aquatic ecosystems in the country. Water management is a challenge in South Africa because of the socio-economic pressure and other factors such as mine wastewater, eutrophication, salinisation, and emerging contaminants. This research investigated some water quality parameters of Bloukrans, Buffalo, Swartkops and Tyhume Rivers in Eastern Cape Province of South Africa for three seasons. The parameters investigated include the physicochemical properties, functional groups of organic compounds, presence of endocrine-disrupting compounds and heavy metals in the rivers and wastewater effluents from wastewater treatment plants (WWTPs) released into these rivers. The aims were to determine the concentrations of these parameters in the rivers and wastewater effluents, compare the concentration levels with recommended values for aquatic lives, domestic and agricultural purposes, thereby contributing to the effective management of water in South Africa. Water samples were collected for analyses at upstream, midstream and downstream reaches of the rivers. In contrast, wastewater influent and effluent samples were obtained from wastewater treatment plants releasing effluents to the rivers. Some physicochemical parameters were studied onsite with specialised meters while others analysed in the laboratory with ultraviolet (UV) spectroscopy. Chemical functional groups in the samples were determined with Fourier-transformed infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopies. The Endocrine-disrupting compounds and heavy metals were determined with liquid chromatography coupled to a mass spectrometer (LC-MS/MS) and inductively coupled plasma with a mass spectrometer (ICP-MS) respectively. Method validation and calibration for all the spectrometry yielded good linearity (r2 > 0.99). The results showed high oxygen demand above the concentration recommended by the South Africa Department of water affairs and forestry (DWAF) for Alice and Uitenhage wastewater effluents, midstream and downstream river samples. Phosphate concentrations were higher than the recommended level in wastewater effluents. Sulphate concentration in the Bloukrans River was higher than the recommended value. The pH values of rivers at midstream and downstream reaches were higher than 8.0 except in Bloukrans River, where it was around 7.0. The functional group analyses show the presence of substituted aromatic compounds, alkyl halides, chlorobenzenes, vinylidenes, amides, amines, urethanes, cycloalkanes, acetonitriles, methenamine, imidazole and phenolic compounds among others, in the samples. The presence of these functional groups in the water samples is an indication of pollution by volatile organic compounds, persistent organic pollutants and pharmaceuticals. Results of LC-MS/MS analysis show that endocrine-disrupting compounds (EDCs) were present in the rivers and wastewaters samples. Descriptive statistics showed the mean concentrations of the EDCs in the samples as nonylphenol > dichlorophenol > bisphenol A > triclosan > octylphenol > imidazole > atrazine > triazole > estrone > estradiol. The results of the heavy metal analysis show that chromium had the highest mean concentration in the samples. The mean metals concentrations in the samples were in the order of Cr > Ni > Mn > Cu > As > Pb > Cd > Hg > Zn. The results showed an increase in the concentrations of metals in the rivers over the years. The chromium, manganese, nickel, copper, zinc, arsenic, cadmium, lead and mercury concentrations in the lower reaches of the rivers and wastewater effluents were higher than the values recommended by the United Nations Environmental Programme (UNEP) and DWAF. Improvement is necessary in wastewater treatment and adequate legislation on chemical usage. Some chemicals banned in developed countries, such as atrazine, were encountered in this study. , Thesis (PhD) -- Faculty of Science, Institute of Water Research, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Farounbi, Adebayo Ibikunle
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177327 , vital:42810 , DOI 10.21504/10962/177327
- Description: South Africa is developing with increasing population, and so is the demand for use and access to water resources. Surface water is critical to the country because it provides about 77% of the needed water resources. Low rainfall (about 450 mm annually) with little runoffs to boost the rivers aggravates the problems of surface waters. Expansion of industrial and agricultural activities coupled with the population pressure had an impact on water quality, availability and the state of aquatic ecosystems in the country. Water management is a challenge in South Africa because of the socio-economic pressure and other factors such as mine wastewater, eutrophication, salinisation, and emerging contaminants. This research investigated some water quality parameters of Bloukrans, Buffalo, Swartkops and Tyhume Rivers in Eastern Cape Province of South Africa for three seasons. The parameters investigated include the physicochemical properties, functional groups of organic compounds, presence of endocrine-disrupting compounds and heavy metals in the rivers and wastewater effluents from wastewater treatment plants (WWTPs) released into these rivers. The aims were to determine the concentrations of these parameters in the rivers and wastewater effluents, compare the concentration levels with recommended values for aquatic lives, domestic and agricultural purposes, thereby contributing to the effective management of water in South Africa. Water samples were collected for analyses at upstream, midstream and downstream reaches of the rivers. In contrast, wastewater influent and effluent samples were obtained from wastewater treatment plants releasing effluents to the rivers. Some physicochemical parameters were studied onsite with specialised meters while others analysed in the laboratory with ultraviolet (UV) spectroscopy. Chemical functional groups in the samples were determined with Fourier-transformed infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopies. The Endocrine-disrupting compounds and heavy metals were determined with liquid chromatography coupled to a mass spectrometer (LC-MS/MS) and inductively coupled plasma with a mass spectrometer (ICP-MS) respectively. Method validation and calibration for all the spectrometry yielded good linearity (r2 > 0.99). The results showed high oxygen demand above the concentration recommended by the South Africa Department of water affairs and forestry (DWAF) for Alice and Uitenhage wastewater effluents, midstream and downstream river samples. Phosphate concentrations were higher than the recommended level in wastewater effluents. Sulphate concentration in the Bloukrans River was higher than the recommended value. The pH values of rivers at midstream and downstream reaches were higher than 8.0 except in Bloukrans River, where it was around 7.0. The functional group analyses show the presence of substituted aromatic compounds, alkyl halides, chlorobenzenes, vinylidenes, amides, amines, urethanes, cycloalkanes, acetonitriles, methenamine, imidazole and phenolic compounds among others, in the samples. The presence of these functional groups in the water samples is an indication of pollution by volatile organic compounds, persistent organic pollutants and pharmaceuticals. Results of LC-MS/MS analysis show that endocrine-disrupting compounds (EDCs) were present in the rivers and wastewaters samples. Descriptive statistics showed the mean concentrations of the EDCs in the samples as nonylphenol > dichlorophenol > bisphenol A > triclosan > octylphenol > imidazole > atrazine > triazole > estrone > estradiol. The results of the heavy metal analysis show that chromium had the highest mean concentration in the samples. The mean metals concentrations in the samples were in the order of Cr > Ni > Mn > Cu > As > Pb > Cd > Hg > Zn. The results showed an increase in the concentrations of metals in the rivers over the years. The chromium, manganese, nickel, copper, zinc, arsenic, cadmium, lead and mercury concentrations in the lower reaches of the rivers and wastewater effluents were higher than the values recommended by the United Nations Environmental Programme (UNEP) and DWAF. Improvement is necessary in wastewater treatment and adequate legislation on chemical usage. Some chemicals banned in developed countries, such as atrazine, were encountered in this study. , Thesis (PhD) -- Faculty of Science, Institute of Water Research, 2021
- Full Text:
- Date Issued: 2021-04
Detection and effects of selected pharmaceutical compounds from selected water bodies in the Eastern Cape Province, South Africa
- Authors: Setshedi, Koketso Josinah
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/177074 , vital:42788
- Description: Theses embargoed. Release date March 2023. , Thesis (MSc) -- Faculty of Pharmacy, Department of Pharmaceutical Chemistry, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Setshedi, Koketso Josinah
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/177074 , vital:42788
- Description: Theses embargoed. Release date March 2023. , Thesis (MSc) -- Faculty of Pharmacy, Department of Pharmaceutical Chemistry, 2021
- Full Text:
- Date Issued: 2021-04