Browsing by Author "Okoh, A.I."
Now showing 1 - 5 of 5
Results Per Page
Sort Options
Item Assessment of the desalination potentials of some algal/cyanobacterial strains isolated from Buffalo River in the Eastern Cape Province, South Africa.(University of Fort Hare, 2024) Mnikana-Cibi, Yolanda Blessings; Okoh, A.I.Water scarcity is a global disaster, especially in arid and semi-arid countries including South Africa. When compared to the global average, South Africa's average rainfall is very low. Furthermore, freshwater scarcity is expected to worsen over the next few decades as the human population and demands grow, and the development of sustainable, energy-efficient desalination technologies could make about 97% of the water in the oceans become a useable substitute. Biodesalination using cyanobacteria is an emerging approach that could be used to achieve this feat. As a source of nutrition for growth, algae and cyanobacteria absorb ions that have a negative impact on water quality, and cyanobacteria can grow in high salt concentrations while producing a low-salt environment. Both biosorption and bioaccumulation contribute to salt removal, with biosorption having the highest salt removal efficacy. This study explores the potential of desalination potential of freshwater and marine algal/cyanobacterial strains isolated from the Buffalo River in the Eastern Cape Province, South Africa. It supports sustainable development goals related to clean water, climate action, and environmental conservation. The standard culture-based method was used for the isolation of presumptive algal and cyanobacterial strains from water collected from the Buffalo River. The presumptive cyanobacterial isolates with desalination potential were then sent to Inqaba Biotech for identification. Identification was done based on Next-generation sequencing (NGS). In total, 25 species were identified, comprising 12 cyanobacteria (Anabaena sp., MAG: Pseudanabaena, Pseudanabaena sp., Nostoc minutum, Synechococcus lividus, Hydrococcus rivularis, Spirulina subsalsa, Chroococcus sp.,Cyanobacterium aponinum, MAG: Dolichospermum, Dolichospermum sp., Chamaesiphon minutus,), diatom (Nitzschia inconspicua), and 12 green algae (Coelastrella sp., Chlamydomonas sp., Chlorella vulgaris, Monoraphidium sp., Parachlorella kessleri, Chlorella sorokiniana, Tetradesmus obliquus, Monoraphidium sp., Picochlorum costavermella, Stichococcus bacillaris, Haematococcus lacustris) isolated from the buffalo River. Out of the 20 screened isolates, 5 non-axenic (25%) strains exhibited biodesalination potential of more than 40% salinity reduction. These 5 non-axenic cultures named: 3 Wimpy, 12 Grinika, 14 Grinika, 15 Ndevana, 20 Buffalo Pass were further investigated for optimisation of culture conditions for high algal biomass to improve the efficiency of the algae/cyanobacteria biodesalination. The optimum parameters investigated included carbon source, nitrogen source, pH, light source, and effects of different salinity concentration. Salinity reduction was achieved by up to 92% salinity reduction at salt concentrations of 20 ppt seawater. Both sucrose and nitrates were found to be the best carbon and nitrogen sources under high salinity conditions yielding 55.5% and 50.0 % respectively at the regulated optimum parameters of shaker speed (180 rpm), temperature (30 ± 3 °C), 40 Watts cool white, fluorescent bulbs, and pH 7.5. To prevent the release of salt and cyanotoxins produced by cyanobacteria reverting into the desalinated water, membrane filtration was used to safely separate and recover algal and cyanobacteria strains from desalinated water. Removal of cells from the desalinated water resulted in a significant salinity reduction. To address public health and safety concerns, an in vitro toxicology study was conducted using the CyQUANT LDH Cytotoxicity Assay Kit to assess the potential risks associated with desalinated water, which turned out to be negative. The use of cyanobacteria and photosynthetic organisms in the desalination of seawater has been proven in this study. Algal strains have been shown to produce significant biomass in seawater while at the same time reducing the salt content. Using optimal conditions for algal/cyanobacterial growth, such as light, carbon, and nitrogen sources enables cyanobacteria to grow at high densities and enables future biological processes for sustainable water treatment applications. However, energy sources were a major challenge in this study. Alternative methods should be investigated for the supply of artificial energy sources. Equally, more stringent monitoring of physiological changes caused by ionic stress should be investigated. Understanding how salinity affects cell growth and viability would enable scaling up cyanobacterial growth to meet the demands of water treatment scenarios.Item Enterococcus pathotypes as reservoirs of antibiotic resistance determinants in the Kat river and Fort Beaufort abstraction waters.(University of Fort Hare, 2014) Ntloko, Phindiwe; Okoh, A.I.In this study, 400 presumptive Enterococcus isolates previously recovered from Kat River and Fort Beaufort Abstraction water dam were subjected to molecular confirmation and pathotyping. Two hundred and seventy-four (68%) of these isolates were confirmed to be enterococci species. Confirmations studies were polymerase chain reaction (PCR) based, using enterococci specific primers targeting the tuf gene. The confirmed enterococci isolates were further differentiated into their pathotypes, the targets of which were: E. faecalis, E. avium, E. hirae, E. casseliflavarus and E. gallinarum using well documented species specific primer sequences. E. faecalis accounted for 20% of the isolates, followed by E. avium (16%), E. hirae (13%), E. casseliflavarus (5%) and E. gallinarum (3%). Furthermore, all the confirmed isolates were analysed for antibiotic susceptibilities using a panel of nine different antibiotics, namely vancomycin, linezolid, ciprofloxacin, ampicillin, gentamicin, chloramphenicol, tetracycline, erythromycin, penicillin, and those that were resistant were assayed for the presence of relevant antibiotic resistance genes. All the 274 isolates were found to harbour vanA resistance gene confirming their phenotypic resistance to the vancomycin. Similarly, 60% (109/180) of the isolates showed phenotypic resistance to erythromycin which was further confirmed by the presence of ermA genes in these isolates. The presence of antibiotic resistant bacteria in surface waters poses a risk to public health.Item General Microbiology: MIC 511, Honours Examinations June 2023(University of Fort Hare, 2023-06) Okoh, A.I.; Green, E.Item Incidence and diversity of SARS-CoV-2 from wastewater samples recovered from selected municipal wastewater treatment facilities in Buffalo City Metropolitan Municipality, Eastern Cape Province, South Africa.(University of Fort Hare, 2024) Mayoyo, Okuhle; Okoh, A.I.; Msolo, L.Wastewater surveillance has gained traction since the Severe Acute Respiratory Syndrome Coronavirus type 2 (SARS-CoV-2) induced global health crisis. SARS-CoV-2 is an enveloped Betacoronavirus that has evolved into numerous variants. The virus and its genomic variants contributed to COVID-19 transmission dynamics, disease severity, immune-response escape, and economic collapse in developing countries. This study elucidated the incidence and diversity of SARS-CoV-2 in municipal wastewaters in the Buffalo City Metropolitan Municipality (BCMM). Wastewater influent samples were aseptically collected monthly from ten wastewater treatment facilities in the municipality over a 12-month period from June 2021 to June 2022 to represent the four seasons of autumn, spring, summer and winter in South Africa. A total of 494 wastewater-influent samples were collected, and the total viral RNA was extracted from the samples following the standard operating protocols. The Quantitative Reverse Transcription Polymerase Chain Reaction (RT-qPCR) was utilised to screen for the nucleocapsid phosphoprotein-inducing gene of SARS-CoV-2. Subsequently, the TaqMan SARS-CoV-2 mutation panel genotyping-molecular-specific RT-PCR assay, targeting the single nucleotide polymorphisms (SNPs) (delH69V70, E484K, K417N, L452R, N501Y, P681H and P681R), was used to rapidly detect SARS-CoV-2 variants with the panel related to the B.1617.2 and the B.1.1.529 lineages of SARS-CoV-2 variants. About 71% (n = 351) of the 494 samples were positive for the nucleocapsid gene, indicating SARS-CoV-2 presence. The total viral load retrieved from all study sites in winter (2021) was a total concentration of 22.08 × 104 GC/mL, spring (2021) 13.09 × 104 GC/mL, summer (2021-2022) 7.61 × 104 GC/mL and autumn (2022) 29.30 × 104 GC/mL. The circulation of variants of concern (VOC) was ascertained as 93% of SARS-CoV-2 samples (n = 45) with viral loads ≥ 1000 GC/mL were positive for the target SNPs. The predominant amino acid mutation was the N501Y (22%), shared between Alpha (B.1.17), Beta (B.1.33, B.1.351) and Omicron lineages. The geospatial analysis revealed the EB WWTP, a combined sewer network, as the diverse SARS-CoV-2 genome hotspot. Nevertheless, the spike protein mutations linked to VOCs were circulating in other areas. Overall, a direct correlation was observed between SARS-CoV-2 signals in wastewater, VOC-linked SNPs and clinical cases in the region. A significant spike in all three factors was observed in September 2021, during the third epidemic. VOC Delta (B.1.617.2) was the predominant variant during this period. Furthermore, a more significant peak was in SARS-CoV-2 with a total viral load exceeding 20 × 104 GC/mL, L452R, N501Y and P681H were detected more frequently during this epidemic driven by BA.4 & BA.5. This finding emphasises the significance of wastewater-based epidemiology as a non-invasive populationbased surveillance strategy to monitor circulating pathogens and diseases. Quantitative Microbial Risk Assessment (QMRA) model was carried out to evaluate the potential occupational health risks of exposure to SARS-CoV-2 amongst wastewater treatment plant workers at different exposure scenarios. As expected, the P(i) values for wastewater treatment plant (WWTP) operators working for 6 hours without personal protective equipment (PPE) and inadvertently exposed to up to 20 mL of contaminated bioaerosol, droplets and fomites were 35.9 × 10-2 (winter 2021), 5.1 × 10-2 (spring 2021), 6.8 × 10-2 (summer 2021-2022), and 18.2 × 10-2 (autumn 2022). There was no significant correlation between the seasons and the potential health risks (p ≥ 0.05). Therefore, the potential health risks associated with the incidence of the SARS-CoV-2 genome in wastewater across the epidemiological seasons in the study WWTPs are low at a significance level of 95%. Nevertheless, the controversies in the literature regarding the viability of SARS-CoV-2 in the wastewater milieu accentuate the coronavirus as a public health concern and demand stringent precautionary measures in occupational settings. Irrevocably, the incidence of the SARS-CoV-2 genome in the municipal wastewaters of the BCCM is an indicator of the circulation of the virus in the metropolitan. The implication of occupational and environmental safety protocols is crucial to curb the dissemination of the pathogen, and wastewater-based epidemiology coupled with QMRA are imperative approaches that could be continuously employed as complementary tools for clinical surveillance. This surveillance strategy for communicable diseases is imperative for reaching the 2030 Agenda for Sustainable Development.Item Techniques in Microbiology: MIC 512, Honours Examinations June 2023(University of Fort Hare, 2023-05) Okoh, A.I.; Green, E.