UMP Scholarship Collection:

Encephalartos lanatus-associated bacteria and extracellular enzyme activities improve soil nutrition in nutrient-deficient grassland ecosystems.

2026-04-01T10:04:06Z

Title: Encephalartos lanatus-associated bacteria and extracellular enzyme activities improve soil nutrition in nutrient-deficient grassland ecosystems. Authors: Sigasa, Memory.; Magadlela, Anathi.; P´erez-Fern´andez, María A.; Otang-Mbeng, Wilfred.; Suinyuy, Terence N. Abstract: Encephalartos lanatus, commonly called ‘Olifants River Cycad’, is slow-growing and thrives in nutrient-deficient and acidic grassland soils. Like other Encephalartos spp., E. lanatus possess coralloid roots that host nutrient cycling microbes that may enhance soil and plant health and landscape productivity. However, identification of these microbes and their role in soil nutrient improvement have been documented for forest and savanna woodland Encephalartos spp., with limited knowledge on grassland species. The knowledge gap challenges the development of a holistic conservation strategy for grassland cycads. This study identified E. lanatus coralloid roots, rhizosphere, and bulk soils bacterial communities, and assessed the nutrient status and enzyme activities of both soils. Bulk and rhizosphere soils, and E. lanatus coralloid roots were sampled from a > 300 E. lanatus plant population growing in a rocky grassland at Botshabelo in Middleburg, Mpumalanga for nutrient analysis, enzyme activity assays, and bacterial identification. Nutrient concentration was higher in rhizosphere (20.54±3.40) than bulk (17.47±3.24) soils but not significantly different (p = 0.55). Concentration of magnesium and manganese were significantly higher (p < 0.05) in rhizosphere than bulk soils. Nitrogen, phosphorus, potassium and calcium were higher in rhizosphere than bulk soils but did not differ significantly (p > 0.05). Acid phosphatase and nitrate reductase enzyme activities were significantly (p < 0.05) higher in rhizosphere than bulk soils. Nutrient cycling bacteria of the genera Bacillus, Burkholderia, Enterobacter, Paraburkholderia, Pseudomonas and Rhizobium characterised coralloid roots, rhizosphere and bulk soils bacterial communities. The high nitrogen, phosphorus and potassium concentrations in rhizosphere as compared to bulk soils suggest that nutrient cycling bacteria in the coralloid roots, rhizosphere and bulk soils, and increased enzyme activities may be contributing to improving soil and E. lanatus health and productivity in nutrient-poor grassland ecosystem. This underscores the role of E. lanatus in soil nutrient improvement and the need to develop holistic conservation approaches for grassland cycads. I Description: Published version

Effect of hydrocolloids on the quality and functional characteristics of banana gluten-free pasta.

2025-11-17T13:29:36Z

Title: Effect of hydrocolloids on the quality and functional characteristics of banana gluten-free pasta. Authors: Dibakoane, Siphosethu Richard. Abstract: Unripe banana flour pasta products are not preferred by consumers due to their high cooking losses, darker colour, and stickiness caused by low protein levels in the flour. To address these challenges, this study assessed the combined effect of three types of hydrocolloids, namely egg white (EW), guar gum (GG), and xanthan gum (XG), on the quality and functional characteristics of banana flour–based pasta. The pasta samples were made using distilled water (36.1 – 40.1%), wheat flour (60.6%), banana flour (36.0%) with varying levels of hydrocolloids (18 – 22% and 0.5 – 4.5%). The samples were dried overnight and stored in sealed and airtight plastics pending further analysis. One-way analysis of variance (ANOVA) and response surface regression analysis were used to analyse relationships between inclusion levels of hydrocolloids and the quality and functional characteristics of the pasta. The cooking time, and hardness of the pasta showed linear and quadratic increases (p<0.05) in response to incremental levels of the hydrocolloids. However, the cooking loss showed a linear decrease (p<0.05) in response to incremental levels of the hydrocolloids. The adhesiveness of the pasta showed linear increase (p<0.05) in response to incremental levels of EW and XG, whilst that of pasta containing GG showed linear decrease (p<0.05). The colour parameters of the uncooked pasta showed linear and quadratic increases (p<0.05) in response to incremental levels of the hydrocolloids. However, the colour of the cooked pasta, except for lightness showed a linear and quadratic decrease (p<0.05) in response to incremental levels of the hydrocolloids. The pasting properties of pasta containing EW showed a linear decrease (p<0.05) in response to incremental levels of EW. In contrast, the pasting properties of pasta containing GG and XG showed a linear increase (p<0.05) in response to incremental levels of the hydrocolloids. Moreover, xanthan gum was the only hydrocolloid that significantly influenced (p<0.05) the gel texture of the paste. The findings of the present study demonstrated that hydrocolloids can enhance the quality and functional characteristics of banana flour-based pasta. However, the influence of hydrocolloids dependent on the type (source) and their inclusion levels. To optimize quality and functional characteristics texture of the banana flour pasta, inclusion levels of EW should be 19% while those of GG and XG should be 2 – 3%. The findings of study could be used to enhance the quality and functional characteristics of other gluten-free pasta products to improve food security and consumer acceptability. Description: Dissertation (Master(Agriculture and Natural Sciences))--University of Mpumalanga, 2025

Nutraceutical properties of wild fruit plants in Mpumalanga.

2025-11-17T08:35:09Z

Title: Nutraceutical properties of wild fruit plants in Mpumalanga. Authors: Chauke, Sinorita. Abstract: Nutraceuticals have emerged as reliable substances for managing health conditions by providing both nutrition and phytotherapy. Wild fruit plants, with a long history of use by local communities for nutritional and medicinal purposes, represent promising candidates for nutraceutical development. This study aimed to explore the nutraceutical properties of wild fruit plants harvested from Bushbuckridge local municipality, Mpumalanga Province, South Africa. A comprehensive literature survey on wild fruit plants in Mpumalanga Province identified five key studies documenting a total of 83 wild fruit plant species from 61 genera and 31 families. The review highlighted research gaps, including the need to explore under-documented regions and variations in the cultural use of these plants across different ethnic groups. Based on their medicinal and nutritional uses, frequency of citation, and research gaps, six wild fruit plants were selected for further investigation: Carissa spinarum L., Diospyros mespiliformis Hochst. ex A.DC., Euclea crispa (Thunb.) Gürke, Ficus thonningii Blume, Strychnos spinosa Lam., and Strychnos madagascariensis Poir. The antimicrobial activity of the leaves of these plant species were tested against the bacterial skin pathogens Klebsiella pneumoniae and Pseudomonas aeruginosa. Using disc diffusion, the hexane extracts of D. mespiliformis and E. crispa had an inhibition zone of 28 mm against P. aeruginosa. The microdilution assay also revealed that the methanol extract of D. mespiliformis exhibited the strongest activity against both pathogens, with a minimum inhibitory concentration (MIC) ranging from 0.781 to 1.563 mg/mL. The antioxidant potential of the plant leaves was determined using 2,2-diphenyl-1-picryhydrazyl (DPPH) and Ferric Reducing Antioxidant Power (FRAP) assays. The methanol extract of E. crispa demonstrated potent antioxidant activity, with a half-maximal inhibitory concentration (IC50) of 1.42 μg/mL, comparable to standard ascorbic acid. Other species, including C. spinarum and S. spinosa, also showed promising antioxidant activity, highlighting their potential to mitigate oxidative stress-related conditions. The nutritional and mineral compositions of F. thonningii fruits and the pulp, peel, and seeds of D. mespiliformis and S. spinosa were analysed. The proximate analysis of the fruits revealed significant protein and fibre content. The elemental analysis of the leaves and fruit showed a wide range of minerals present in the leaves and fruit. Notably, S. spinosa peels contained 44.21% fibre, while its leaves were rich in manganese (1,728 mg/kg). Elemental analysis identified essential minerals like calcium, iron, and magnesium, but also detected heavy metals, such as arsenic, cadmium, and chromium, in the fruits, posing potential toxicity risks. The study demonstrates that wild fruit plants possess significant nutraceutical potential due to their antimicrobial, antioxidant, and nutritional properties. These findings validate their traditional uses and underscore their potential role in addressing food insecurity, managing health disorders, and developing nutraceutical products. Description: Dissertation (Master of Science)--University of Mpumalanga, 2025

The ecology of encephalartos lanatus in Middelburg district, Mpumalanga Province (South Africa).

2025-11-14T15:04:38Z

Title: The ecology of encephalartos lanatus in Middelburg district, Mpumalanga Province (South Africa). Authors: Sigasa, Nonele Memory. Abstract: Cycads are long-lived, slow-growing gymnosperms that were once widely distributed but today are limited to the tropical and subtropical regions of the world. Cycads are of conservation importance because of their unique ecology. First, they are the only gymnosperms that provide an important ecosystem service of nutrient cycling, such as nitrogen fixation, through their association with nitrogen-fixing bacteria present in specialized coralloid roots that are similar to root nodules in legumes. Second, they have unique life histories based on their growth. They are a group of dioecious gymnosperms that occur in various life stages within a population. Third, they are the most threatened plant group on Earth, with over 50 % of the more than 300 species facing a high risk of extinction. The extinction is well noted for the African Encephalartos species, which are threatened by habitat loss through transformation, frequent fires, over-exploitation for landscaping and medicinal purposes, reproduction failures and other natural courses like herbivory and poor dispersal, which all affect the population health and structure. There is little knowledge on the ecology of Encephalartos cycads, and their extinction will lead to a decline in ecosystem services, and also. information about the diversity of nitrogen-fixing bacteria and other associated microbes in the roots and soils of Encephalartos species, and knowledge of their contribution to soil nutrient improvement is limited. This study, therefore, aimed to investigate the effects of disturbances/threats to E. lanatus health and population structure. Additionally, the study investigates the associated roots and soil microbes and the effects of E. lanatus on soil nutrient status. Encephalartos lanatus in a protected area in Botshabelo, Mpumalanga, is prone to fire, herbivory, and habitat conversion, and therefore serves as a model species for the aim of the study. The effects of fire and herbivory on E. lanatus health and population structure were assessed by counting and measuring all plants (seedlings, juveniles, adults, coning) in burnt and unburnt plots in Botshabelo. The plants were sexed based on the presence of live cones, remnants of cones from a previous season, or seedlings under the adult plant. Cone damage was assessed by counting and recording cones that were completely or partially damaged by fire and/or herbivores. For soil nutrient status, soil samples were collected from the rhizosphere of a total of 20 adult E. lanatus plants (10 each from burnt and unburnt plots), and 20 control samples were collected 5 m away from each target plant, and analyzed for soil nutrients (nitrogen [N], phosphorus [P], potassium [K], calcium [Ca], magnesium [Mg], manganese [Mn], copper [Cu], zinc [Zn], pH, acid saturation, total cation exchange, exchangeable acidity, and organic carbon [C]), enzyme activities using ꞵ-(D)-glucosaminidase, ꞵ-glucosidase, and phosphatase (alkaline & acid). Furthermore, the rhizosphere and non-rhizosphere soils, together with coralloid roots, were analyzed for N-fixing, N-cycling, and P-solubilizing bacteria and other associated microbes. The data obtained for the effect of fire and herbivory on population structure was analyzed using analysis of covariance (ANCOVA) and analysis of variance (ANOVA) in RStudio. A two-sample t-test in Statistix 10 software was used to analyse the differences in nutrient concentration and enzyme activities in the rhizosphere and non-rhizosphere soils. The coralloid roots, rhizosphere and non-rhizosphere soils were analysed for their microbial composition. The study revealed that the population follows a “J” structure with a greater (P < 0.01) number of adults compared to any other life stage, and E. lanatus populations that were affected by fire produced a higher number of cones and were more prone to baboon damage than the cones in the unburnt sections. Rhizosphere soils had a significantly higher concentration (P < 0.05) of Mg and Mn than non-rhizosphere soils. In addition, both the rhizosphere and non-rhizosphere soils had significantly similar concentrations (P > 0.05) of N, P, K, Ca, Cu, Zn, pH, acid saturation, total cation exchange, exchangeable acidity, and organic C. Specifically, ten bacteria families were identified in the E. lanatus rhizosphere, non-rhizosphere soils, and coralloid roots. The Burkholderiaceae and Rhizobiaceae were the most dominant microbial families in both soils. The enzymes ꞵ-(D)-glucosaminidase and alkaline phosphatase were higher in the rhizosphere than in the non-rhizosphere soils but not significant (P > 0.05). In contrast, acid phosphatase, nitrate reductase and beta-glucosidase were significantly higher (P < 0.05) in the rhizosphere than in the non-rhizosphere soils. In conclusion, the study provides evidence that E. lanatus face challenges in their natural habitat. However, E. lanatus have developed coping mechanisms to withstand the harsh environment and host N-fixing, N-cycling and P-solubilizing microbes that assist the plants to thrive in nutrient-poor conditions. Generally, the current findings show that the identified N-fixing and nutrient-cycling bacteria, and their associated enzymes in E. lanatus coralloid roots, rhizosphere, and non-rhizosphere soils account for soil nutrient status improvement in the E. lanatus nutrient-poor ecosystem. Description: Dissertation (Master(Agriculture and Natural Sciences))--University of Mpumalanga, 2025