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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

African mead biotechnology and indigenous knowledge systems in iQhilika process development

Cambray, Garth Anton January 2005 (has links)
While the production of mead, a fermented honey beverage, has declined in popularity around the world in recent centuries, a substantial mead industry continues to exist in Africa with an estimated annual production of 1 to 1.7 billion litres. This is largely an ‘invisible industry’, and has functioned outside the formal economy due to proscription of indigenous beverages during colonial times. The traditional African mead industry is, however, also now under pressure due to the environmental degradation of scarce natural ingredients, urbanisation and loss of indigenous knowledge systems (IKS) and, with time, the beverage will likely follow the declining trend of mead consumption observed elsewhere. An analysis of early reports of African mead production suggested that the Khoi-San, among the earliest inhabitants of the continent, are the originators of the mead making techniques which use fibrous plant materials derived from specific plant species, to facilitate mead fermentation in some way. The Eastern Cape represents a region with a large body of Khoi-San IKS preserved in their descendants among the Afrikaans and Xhosa populations. A survey to establish a baseline of mead-making technology in the Eastern Cape was undertaken, and involved interviewing traditional mead makers across an area of roughly 100 000 km2, showing that the mead, iQhilika(Xhosa) Kari (Khoi-San/Afrikaans), is produced using a very similar process throughout the region. This involves the roots of a Trichodiadema sp. plant (imoela – Xhosa, karimoer – Afrikaans/Khoi-San), honey, extract of brood and/or pollen and water. Various other fruit sugar sources were also found to be added at times producing seasonal beverages with unique organoleptic properties. A model traditional iQhilika production operation was investigated in order to describe the main features of the process. Biomass immobilised on Trichodiadema root segments was found to be distributed evenly through the profile of the bioreactor resulting in a well mixed fermentation and a productivity of 0.74 g EtOH/l/h. In the initial stages of fermentation, the ethanol yield was highest in the mid-regions of the bioreactor, but with time the regions closer to the surface, which had atmospheric contact had a higher yield. This phenomenon was attributed to aerobic fatty acid synthesis which allowed the yeast close to the surface to function more efficiently despite rising ethanol concentrations. The mead contained 44.25 g/l (7 % volume) ethanol produced in a fermentation time of 43.5 h. Yeast biomass in the traditional process was either immobilised in the form of flocs or attached to the Trichodiadema intonsum support. Electron microscopy revealed that the cells were covered in a layer of extra-cellular polymeric substance apparently assisting the immobilization, and which was populated by a consortium of yeasts and bacteria. Yeasts isolated from iQhilika brewed in two regions separated by 350 km were found to be very closely related Saccharomyces cerevisiae strains as determined by molecular genetic analysis. The traditional beverage was found to contain populations of Lactic acid bacteria (LAB), which are known spoilage organisms in other beverages. Spoilage characteristics of these organisms matched descriptions of spoilage provided by the IKS survey. Other possibly beneficial LAB, which may contribute useful flavour compounds, were also found to be present in the system. The basic functional aspects of the traditional process were used to design a continuous bench-scale tower bioreactor and process development was based on the IKS survey. This consisted of a packed bed bioreactor, consisting of 2 mm3 T. intonsum root segments, immobilising a novel Saccharomyces cerevisiae strain isolated from a traditional batch of iQhilika. The bioreactor performed well with a yield of close to the theoretical maximum and an ethanol productivity of 3.45 g EtOH/l/h. The parameters of the 5.6 l/d bench-scale bioreactor were used to design a full-scale production bioreactor with a planned maximum output of 330 l/d. This bioreactor had a productivity of 0.19 g EtOH/l/h. The organoleptic properties of the product produced were considered by a taste panel to be better than those of the product of the bench-scale tower bioreactor. This research was based on the development of IKS which imposed a number of constraints and obligations on the project to ensure environmental, and social, in addition to financial viability of the scale-up operation. Makana Meadery was established in partnership with Rhodes University as an empowerment company which, in addition to undertaking the commercialisation of the iQhilika process, would also develop methods for the production of scarce ingredients traditionally unsustainably sourced from fragile ecosystems, provide beekeeping training and the manufacture of beehives.
2

Indigenous knowledges: a genealogy of representations and applications in developing contexts of environmental education and development in southern Africa

Shava, Soul January 2009 (has links)
This study was developed around concerns about how indigenous knowledges have been represented and applied in environment and development education. The first phase of the study is a genealogical analysis after Michel Foucault. This probes representations and applications of plant-based indigenous knowledge in selected anthropological, botanical and environmental education texts in southern Africa. The emerging insights were deepened using a Social (Critical) Realism vantage point after Margaret Archer to shed light on agential issues in environmental education and development contexts. Here her morphogenetic/morphostatic analysis of social transformation or reproduction is used to trace changes in indigenous knowledge representations and applications over time (from the pre-colonial into the post-colonial era). The second phase uses the same perspectives and tools to extend the analysis of power/knowledge relationships into the interface of indigenous communities and modern institutions in two case study settings in the Eastern Cape of South Africa. This study reveals colonially-derived hegemonic processes of modern/Western scientific institutional representations/interpretations of the knowledges of indigenous communities. It also tracks a continuing trajectory of their dominating and prescriptive mediating control over local knowledges from the pre-colonial context through into the post-colonial period in southern Africa. The analysis reveals how this hegemony is sustained through the deployment of institutional strategies of representation that transform local knowledges into the disciplinary knowledge discourses of modern scientific institutions. These representational strategies therefore generate/reproduce and validate disciplinary discourses about the other, constructing disciplinary 'regimes of truth'. In this way modern institutions appropriate and displace indigenous/local knowledges, silence the voices of local communities and regulate individual and community agency within a continuing subjugation of indigenous knowledges. This study reveals how working within modern institutions and disciplinary knowledges in participative education and development interactions can serve to implicate indigenous researchers in these institutional hegemonic processes. The study also notes evidence of a continued resistance to hegemonic Western knowledge discourses as indigenous communities have sustained many knowledge practices alongside Western knowledge discourses. There is also evidence of a recent emergence of counter-hegemonic indigenous knowledge discourses in environmental education and development practices in southern Africa. It is noted that these have been contingent upon the changing political terrain in southern Africa as this has opened the way for alternative discourses to the dominant conventional Western knowledges in formal education and development contexts. The counterhegemonic discourses invert power/knowledge relations, decentre hegemonic discourses and reposition indigenous knowledges in formal education and development contexts. This study suggests the need to foreground indigenous knowledges as a process of knowledge decolonisation that gives contextual and epistemic relevance to environmental education and development processes. This calls for a need for new strategies to transform existing institutions by creating enabling spaces for the representational inclusion of indigenous knowledges in formal/conventional knowledge discourses and their application in social contexts. This opens up possibilities for plural knowledge representations and for their integrative and reciprocal co-engagement in situated contexts of environmental education and development in southern Africa.

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