Browsing by Author "Ncube, T."
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- ItemCloning Cellulase Genes from Victoria Falls Rainforest Decaying Logs Metagenome(Sciendo, 2024) Nyathi, M,; Dhlamini, Z.; Ncube, T.The Victoria Falls rainforest is a protected site whose forest floors harbor a host of cellulolytic microorganisms involved in biomass degradation. This study collected decaying logs and soil from the rainforest for bioprospecting cellulases from their metagenomes. Metagenomic DNA was isolated from the compound sample. Degenerate cellulase primers were used to amplify cellulase genes in the metagenome. The resulting amplicons cloned into Z-competent Escherichia coli DH5α were analyzed by functional screening for the production of cellulase extracellularly. Functional screening of the clones resulted in one clone (Clone-i) testing positivefor extracellular cellulase production. Submerged fermentation of Clone-i was carried out for cellulase production. The cellulases were characterized to determine their activity’s optimum pH and temperature. The diversity of the cellulases produced by Clone-i was determined. Clone-i’s optimum enzyme activity was observed after 72 hours of incubation at 50°C and pH 5. Clone-i produced 80% more exoglucanases as compared to endoglucanases. The cel- lulolytic Clone-i’ isolate shows Victoria Falls rainforest’s potential as an enzyme bioprospecting site, reflecting that metagenomics is a valuable tool in microbial ecology.
- ItemA comparison of antibiotic resistance in microorganisms isolated from chicken and ostrich faeces in Bulawayo, Zimbabwe(International Formulae Group., 2007) Siwela, Andrew H.; Matsaure, Fradereck; Ncube, T.; Olonitola, Olayeni S.; Best, Geoffrey R.Samples of fresh faeces were obtained from a free-range chicken source, three commercial chicken farms and a commercial ostrich farm, all located around Bulawayo City, Zimbabwe, in order to determine the antibiotic resistance profile of selected bacterial isolates of interest in food-related human infections. Samples were prepared at various dilutions and plated on selective media for Coryneforms, Escherichia coli, Enterococcus faecalis and Pseudomonas. The targeted bacteria were isolated as pure cultures and tested for antibiotic resistance to ampicillin, chloramphenicol, oxytetracycline, sulphonamide, streptomycin and tetracycline. Isolates from the faeces of chickens and ostriches in the commercial farms were found to be generally more resistant to streptomycin, tetracycline and oxytetracycline as compared to those from the free- range chickens. This study emphasizes the need to monitor antibiotic resistance genes in the environment and to curb/curtail antibiotic use for growth promotion in farm animals, particularly in developing countries, as continued use will only add to the growing problem of microbial antibiotic resistance.
- ItemConsumer's views and use of labels on food items sold in Bulawayo urban province, Zimbabwe(African scholarly science communication trust., 2017-11) Ncube, T.; Makurunje, S; Dube, S.Food labels are a medium by which consumers acquire knowledge about packaged foods they are considering to purchase. The label makes the first impression about a product and has a great effect on the purchasing decision for consumers. In recent years, literate consumers have become interested in nutritional issues. Lifestyle, age, dietary and safety concerns have been the contributing factors to nutritional awareness by consumers. Nutritional labels can generally have a positive impact on food consumption and may save health-care costs for those consumers with health concerns. On the other hand, for those consumers who are illiterate, price may be more important in making purchase decisions. This study intended to investigate how consumers in Bulawayo Urban Province (Zimbabwe) view and use labels on packaged food items. Seventy-five randomly selected consumers were questioned about their perceptions, attitudes and use of label information using open ended structured questionnaires. The consumers were selected on the basis of being present at the supermarkets at the time of sampling. The respondents were interviewed at different times of the day to cater for employed and unemployed people. The results obtained indicate that the extent to which food labels are used depends on factors such as price of food products, individual health needs and gender. For consumers who use food labels to make their purchase decisions, not all the information on the label is considered. Items on the labels to which the consumers responded were brand, nutritional profile and mass of product in relation to the price. The label elements which were extensively used by consumers in this study are date mark (81.3%), weight of food (89.3%) and price (77.3%). The least used element is the nutritional panel (50.7%). About 44% of the consumers were not sure about the trustworthiness of the information given on food labels. Food labels are important to a greater extent for people with special dietary requirements, while the remainder of the studied population are influenced by price in their purchase decisions. Consumers seem not to understand some of the information on the food labels because of the difficulties in interpreting what is written.
- ItemMetagenome-assembled genomes provide insight into the microbial taxonomy and ecology of the Buhera soda pans, Zimbabwe(PLoS ONE, 2024-12-02) Mangoma, N.; Zhou, N.; Ncube, T.The use of metagenomics has substantially improved our understanding of the taxonomy, phylogeny and ecology of extreme environment microbiomes. Advances in bioinformatics now permit the reconstruction of almost intact microbial genomes, called metagenome-assembled genomes (MAGs), from metagenomic sequence data, allowing for more precise cell-level taxonomic, phylogenetic and functional profiling of uncultured extremophiles. Here, we report on the recovery and characterisation of metagenome-assembled genomes from the Buhera soda pans located in eastern Zimbabwe. This ecosystem has not been studied despite its unique geochemistry and potential as a habitat for unique microorganisms. Metagenomic DNA from the soda pan was sequenced using the DNA Nanoball Sequencing (DNBSEQR) technique. Sequence analysis, done on the Knowledgebase (KBase) platform, involved quality assessment, read assembly, contig binning, and MAG extraction. The MAGs were subjected to taxonomic placement, phylogenetic profiling and functional annotation in order to establish their possible ecological roles in the soda pan ecosystem. A total of 16 bacterial MAGs of medium to high quality were recovered, all distributed among five phyla dominated by Pseudomonadota and Bacillota. Of the ten MAGs that were taxonomically classified up to genus level, five of them belonged to the halophilic/ haloalkaliphilic genera Alkalibacterium, Vibrio, Thioalkalivibrio, Cecembia and Nitrincola, underscoring the importance of haloalkaliphiles in the Buhera soda pans. Functional profiling revealed the possession of diverse carbohydrate-metabolising pathways by the MAGs, with glycolysis and the pentose phosphate pathways appearing to be key pathways in this ecosystem. Several MAGs possessed pathways that implicated them in some key aspects of the nitrogen and sulphur cycle. Some MAGs harboured both sulphate reduction and respiratory pathways, suggesting a possible mechanism of ATP biosynthesis through sulphate respiration. This study demonstrates the feasibility of the recovery and taxonomic and functional annotation of high quality microbial genomes from extreme environments, making it possible to establish the ecological roles and biotechnological potential of uncultured microorganisms.
- ItemProduction of Cellulase by Solid State Fermentation of Brewery Spent Grains Using Aspergillus Niger FGSCa733(Zimbabwe Journal of Science & Technology, 2015) Ncube, T.; Moyo, N. P.; Sibanda, T.Brewery spent grains (BSG) is a waste product of the brewing process. BSG has been used as animal feed, production of value added products, substrate for growth of microorganisms and for extraction of proteins and acids. BSG is high in lignocellulosic matter and may be a candidate substrate for the production of lignocellulolytic enzymes (cellulases and xylanases). In this study, BSG was evaluated for use as a cheap and readily available substrate for the production of extracellular cellulase by Aspergillus niger FGSC A733 during solid state fermentation. The brewery spent grains were subjected to fermentation by Aspergillus niger FGSC A733 at different temperatures ranging from 30 - 40 °C and initial pH ranging from 4.0 - 6.0 for process optimization. Time course analysis was done to determine the optimum incubation period for maximum cellulase production. The effect of alkaline pre-treatment of the substrate on the production of cellulase was analyzed. Cellulase activity was determined by estimating the amount of reducing sugars produced by the enzymes using 3.5 dinitrosalycyclic acid (DNS). Maximum cellulase production was at 35 °C, pH 5.0 and an optimum incubation period of 72 hours. Under optimized conditions, a yield of 73.33 U of cellulase/gram of substrate was obtained. Pre-treatment of the spent grains resulted in a three-fold increase in the production of cellulase. BSG was found to be a suitable substrate for production of cellulase.
- ItemSurvival of Small and Medium Enterprises in Bulawayo Metropolitan Post Covid-19(International Journal of Social Science Research and Review., 2024-05) Nkomo, N.; Mpofu, Q.; Ncube, T.Small businesses are always confronted by a plethora of challenges even when the operating ‘landscape’ is normal. The advent of Covid-19 posed an additional and unconventional difficulty to the already constrained SMEs. The governments used various method to assist SMEs to pull through the pandemic. Post Covid-19 the SMEs are still struggling to generate revenue and reduce operating costs. The paper sought to establish challenges and measures put in place to address the challenges either by SMEs or the government. A qualitative research approach aligned with interpretivism research philosophy was adopted in this paper. The research subjects were selected using a convenient sampling technique. A total of 12 interviews were conducted with the managers and business owners of SMEs. The pertinent challenges faced by SMEs in the Bulawayo metropolitan are high cost of doing business, uncertainty, failure to settle international debits, and anti-business government policies. The SMEs reduce cost through operating from home, virtual meetings, renegotiating contracts with suppliers, staff retrenchment, processes automation, streamlining operation as well as inventory management. The findings also revealed that SMEs increased their revenue through sales promotions and bulky purchases discount, increasing the range of products or services as well as increasing brand awareness. This paper recommends that SMEs’ business should be engineered such that they are highly flexible to adapt and change both the nature of operations and the methods of operating. Business continuity through both succession planning and operational continuity should be at the apex of the priority list of business leaders.
- ItemYeast–insect interactions in southern Africa: Tapping the diversity of yeasts for modern bioprocessing(Wiley Online Library, 2024) Makopa, T.P.; Ncube, T.; Alwasel, S.; Boekhout, T.; Zhou, N.Yeast–insect interactions are one of the most interesting long‐standing relationships whose research has contributed to our understanding of yeast biodiversity and their industrial applications. Although insect‐derived yeast strains are exploited for industrial fermentations, only a limited number of such applications has been documented. The search for novel yeasts from insects is attractive to augment the currently domesticated and commercialized production strains. More specifically, there is potential in tapping the insects native to southern Africa. Southern Africa is home to a disproportionately high fraction of global biodiversity with a cluster of biomes and a broad climate range. This review presents arguments on the roles of the mutualistic relationship between yeasts and insects, the presence of diverse pristine environments and a long history of spontaneous food and beverage fermentations as the potential source of novelty. The review further discusses the recent advances in novelty of industrial strains of insect origin, as well as various ancient and modern‐day industries that could be improved by use yeasts from insect origin. The major focus of the review is on the relationship between insects and yeasts in southern African ecosystems as a potential source of novel industrial yeast strains for modern bioprocesses.