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oai:repository.unam.edu.na:11070/42412026-03-28T22:01:13Zcom_11070_3405com_11070_3311com_11070_3304col_11070_3414

Uzabakiriho, Jean Damascene Ginindza, Thembakazi 2026-03-25T13:40:04Z 2026-03-25T13:40:04Z 2025 http://hdl.handle.net/11070/4241 A thesis submitted in fulfilment of the requirements for the Degree of Master of Science in Microbiology The growing challenges of population expansion, climate change, rising food costs, and unpredictable rainfall patterns have intensified the need for sustainable agricultural practices that boost crop productivity while minimising environmental impacts. One promising strategy involves the combined use of plant growth-promoting endophytic bacteria (PGPEB) with the environmentally friendly hydroponic technique to enhance plant growth and functional quality. This study investigated the influence of seed bacterization with three PGPEB strains, Kosakonia cowanii (KC), Bacillus licheniformis (BL), and Cupriavidus metallidurans (CM), previously isolated from Myrothamnus flabellifolius, on the productivity, nutraceutical accumulation, and antimicrobial activity of okra (Abelmoschus esculentus L. Moench) under hydroponic (Kratky method) conditions. Okra seeds were soaked in single and combined bacterial inocula, germinated under dark conditions, and cultivated in a randomised complete block design with three plants per pot, four replications, and eight treatments. Results revealed significant improvements (P < 0.001) in seed germination percentage and seedling vigour index among inoculated treatments compared to controls, with KC and CM demonstrating strong individual and synergistic effects. BL was notably more effective when used in combination with other bacteria. Furthermore, methanolic extracts of okra pods from bacterized plants exhibited enhanced nutraceutical properties, including elevated total phenolic content (TPC), antioxidant activity (up to 91% DPPH inhibition), and increased inhibition of α-amylase (92%) and αglucosidase (88%), key enzymes linked to diabetes management. Thin-layer chromatography confirmed the presence of carotenes, while polysaccharides were detected across all treatments. Antimicrobial assays revealed substantial activity against pathogens such as Mycobacterium avium, Salmonella typhi, Candida albicans, and Staphylococcus aureus, with the strongest effects observed in methanolic extracts of BL-CM consortia. These findings underscore the potential of PGPEB consortia as eco-friendly bio-stimulants to enhance okra seedling establishment, yield functional bioactive compounds, and contribute to sustainable agriculture and novel nutraceutical and antimicrobial development. Further exploration of PGPEB-based biofertilizers may offer solutions for addressing chronic diseases and rising antibiotic resistance en University of Namibia Plant Growth-Promoting Endophytic Bacteria (PGPEB) Hydroponics Okra (Abelmoschus esculentus) Seed germination Seedling vigour index Nutraceuticals Antioxidant Antidiabetic Antimicrobial activity Namibia University of Namibia Seed bacterization with plant growth-promoting endophytes: Impact on Okra productivity, nutraceuticals and antimicrobial properties Thesisopen.access