Theses and Dissertations

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    Cashew Wastes Biomass in Tanzania Auditing and Characterization: A potential bioresource for production of value-added products
    (2025-06-27) Mwema, Hadija; Kassuwi, Shaaban; Mosha, Prosper; Mshandete, Anthony
    Cashew waste biomass presents a valuable resource for production of value-added products. This study evaluated potential for valorization of cashew wastes (husks, apples and leaves) generated in Mtwara, Tanzania through integrating quantitative and laboratory analysis methods. Chemical composition of cashew waste analyzed were nitrogen, phosphorus, pH, moisture content, total organic matter, ash content, crude fiber, and conductivity. Nitrogen contents of cashew waste including husks, apples and leaves ranged between 1.46 – 2.58%, phosphorus was 0.03 – 0.38%, moisture content between 5.63-23.10%, and pH ranged between 4.44 -5.91. Solid wastes were characterized by crude fiber content in the range of 0.32-0.49 g, ash content between 6.65 – 14.24% and total organic matter content between 95-97%. Results showed that the annual generation of cashew wastes was estimated at 458,874 tons. Out of these, 66% were dried cashew apples, 33% cashew nut shells and 1% cashew husks. These wastes can be transformed into food, feed, bio-energy and bio-based products using bioconversion technologies in integrated and sustainable manner. A scheme for utilization of cashew waste into value added products has been proposed which contributes to environmental preservation. This approach offers a circular economic growth and aligns with global sustainable development goals by responsible consumption and production.
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    Molecular Diversity of Bacteria from a Municipal Dumpsite: Implications to Public Health
    (The Nelson Mandela African Institution of Science and Technology, 2016) Mwaikono, Kilaza Samson
    Despite known risks of inappropriate disposal of solid wastes; most cities in developing countries dispose waste in open dumpsite where humans, animals and microbes interact. This study was done in Arusha municipal dumpsite, Tanzania to investigate the abundance and diversity of bacteria, compare the faecal microbiota of pigs scavenging on dumpsite and indoor reared pigs, and also determine the resistance profile of enteric bacteria from the dumpsite. Domestic wastes, solid biomedical wastes, sludge from the river near the dumpsite and faecal materials of pigs were sampled. Total DNA was extracted and the variable region four (v4) of the 16S rRNA gene was sequenced using high throughput Illumina MiSeq platform. The quality control of sequences and the statistical analyses was performed using Mothur platform. A total of 8,469,294 quality sequences were generated. The mean of bacterial species per sample was 8,243. Diversity was high with an average InvSimpson index of 44.2. Thirty-five bacterial phyla dominated by Firmicutes (38%), Proteobacteria (35%), Bacteroidetes (13%) and Actinobacteria (3%) were found. Overall, 76,862 operational taxonomic units (OTUs) dominated by Acinetobacter (12.1%), Clostridium sensu stricto (4.8%), Proteinclasticum and Lactobacillus (each 3.4%), Enterococcus (2.9%) and Escherichia/Shigella (1.7%) were revealed. There was a significant difference in faecal microbiota between scavenging and indoor reared pigs. Pathogenic genera like Brucella, Rickettsia and Listeria were exclusive to scavenging pigs. In solid biomedical waste, 36.2% of OTUs were related to dehalogenation, 11.6% degraders of aromatic hydrocarbons, 8.5% chlorophenol degradation and Atrazine metabolism 8.3%, and bacteria related to pathogens were 34%. Escherichia/ Shigella, Bacilli and Proteiniclasticum were predominant enteric bacteria. Some bacteria in scavenging pigs had 99% sequence similarity to pathogenic Escherichia furgosonii, Shigella sonnei, Enterococcus faecium and Escherichia coli O154:H4. Over 50% of the isolates were multidrug resistant. The study provides a comprehensive report on diversity of bacteria in Arusha municipal dumpsite. The high species richness shows the complexity of this man-made ecosystem, and calls for further research to assess for a link between human diseases and the dumpsite. This would provide insight into proper disposal of the waste, as well as, limit the risks to human health associated with the dumpsites.
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    Status, physiognomies and economic viability of hydroponic lettuce production in selected areas of Sothern TANZANIA and Central UGANDA
    (2023-08) Gumisiriza, Margaret
    There is an increasing interest and research in soilless farming due to its ability to enhance food production amidst challenges presented by urbanization. However, the adoption of this technology is still very limited in East Africa. This main objective of the research was to study the appropriateness of hydroponics as a feasible urban cropping system for improved vegetable production and accessibility in Uganda. An assessment on status of hydroponics in Northern Tanzania and Central Uganda was carried out using google questionnaires and face-face interviews which revealed limited uptake of the technology majorly due to the high initial costs required. An experiment was set up in central Uganda to evaluate the performance of red and green leafy lettuce produced using a non-greenhouse and non-circulating hydroponic system. Parameters assessed included; plant height, root length, number of leaves, leaf width, fresh weight and dry matter content. Data was analyzed using 2 sample T-test under origin software. A significant difference was noted at harvest for dry matter content (P=0.02, P=0.01), fresh weight (P=0.03, P=0.02) and root length (P=0.01, P=0.02) between red and green lettuce grown under soil and hydroponics in that order at P < 0.05. An economic analysis was done on the system to assess its profitability. Budgeting techniques results showed: Net present value (16.37$), Internal rate of return (12.57%), Profitability index (1.1) and non-discounted payback period (4,5) for annual crop production. Net present value was sensitive to changes in discount rate and unit price while revenue varied with a change in quantities sold and unit price. Regression analysis showed that a variation in the unit price of lettuce was stronger and negatively affected the quantity sold (R=0.91) than the influence the same independent variable on revenue earned (R=0.84). Based on the study results, hydroponics has the potential to act as a suitable alternative in vegetable production system and improve accessibility to vegetables across urban areas in a cost-effective manner. This will also assist in contributing to sustatinable develeopment goals; 3 (good health and wellbeing) and 11 (sustainable cities and communities). There is need to study the perfomance of other vegetables as well as various factors that can improve crop perfomance using the hydroponic system inorder to boost; crop yield, adoption of the system and hence vegetable accessibility and food security. Policy makers and governments should put more efforts in training farming communities about hydroponics.