School of Pure and Applied Sciences

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Author: search.filters.author.Wanjala Paul Muyoma

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    Seasonal Population Trends of Microbial Communities in Oil Tainted Soils in Greater Port Harcourt Area, Nigeria
    (Science Publishing Group, 2024-02-20) Wanjala Paul Muyoma; Wafula, Eliud N.; et.al
    The utilization of oil in industries has devastating effect to the environment. Industrial effluents and oil spills are continuously contaminating the soil. Further, seasonality influences the distribution of pollutants in soil. Consequently, soil microbial biota and ecological processes are affected. This study assessed the effect of seasonality on soil fungal and bacterial communities in oil contaminated soils in 12 selected sites in Greater Port Harcourt Area. Standard analytical procedures were used to obtain bio-physicochemical data from the soil samples and t test was used to analyse data. The levels of total petroleum hydrocarbons (TPH) were above 5000 ppm (DPR recommended limit). There was significant difference (p ≤ 0.000) between the means of TPH in wet and dry seasons. Seasonality influenced % HUF and % HUB in the soils of urban, industrial and agricultural sites. Generally, the seasonality trends showed that there was a declining population of THB, HUB, TF, and HUF from the wet season to the dry season. However, the results show that there was a stable trend in % HUB as compared to oscillations observed in % HUF in oil tainted soils across a seasonal divide. We recommend characterization of the microorganism to identify the best candidate for bioremediation of oil tainted soils across a seasonal divide.
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    Isolation and Identification of Autochthonous Lactic Acid Bacteria from Commonly Consumed African Indigenous Leafy Vegetables in Kenya
    (BACTERIA MDPI, 2023-01-05) Wafula, Eliud N.; Wanjala Paul Muyoma; et.al
    African indigenous leafy vegetables (AILVs) are plants that have been part of the food systems in Sub-Saharan Africa (SSA) for a long time and their leaves, young shoots, flowers, fruits and seeds, stems, tubers, and roots are consumed. These vegetables are high in vitamins, miner als, protein, and secondary metabolites that promote health. This study aimed at isolating, char acterizing, and identifying dominant lactic acid bacteria (LAB) from naturally fermenting com monly consumed AILV in Kenya. A total of 57 LAB strains were isolated and identified based on phenotypic and 16S rRNA gene analyses from three AILVs (23 nightshade leaves, 19 cow peas leaves, and 15 vegetable amaranth). The highest microbial counts were recorded between 48 h and 96 h of fermentation in all AILVs ranging from approximately log 8 to log 9 CFU/mL with an average pH of 3.7. Fermentation of AILVs was dominated by twenty eight Lactobacillus spp. [Lactiplantibacillus plantarum (22), Limosilactobacillus fermentum (3), Lactiplantibacillus pentosus (2) and Lactiplantibacillus casei (1)], eleven Weissella spp. (Weissella cibaria (8), W. confusa (2), and W. muntiaci) six Leuconostoc spp. [Leuconostoc mesenteroides (3), Leuc. citreum (2) and Leuc. lactis (1)], six Pediococcus pentosaceus, four Enterococcus spp. [Enterococcus mundtii (2), E. faecalis (1) and E. durans (1)] and, finally, two Lactococcus garvieae. These bacteria strains are commonly used in food fermentation as starter cultures and as potential probiotics
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    Assessment of the impact of benzene, toluene, ethylbenzene, and xylene (BTEX) on soil microbial population in selected areas of Port Harcourt City, Nigeria
    (ELSEVIER, 2024-12-24) Wanjala Paul Muyoma; Wafula, Eliud N.
    Human activities are on the rise in these areas and consequently, the discharge of BTEX to the environment is on the rise. Benzene, toluene, ethylbenzene, and xylenes (BTEX), are known to cause cancer and mutagenesis. These elements are common in soil, water, and air samples from the environment, which raises the possibility of human exposure. The purpose of this study was to determine the concentrations of BTEX (benzene, toluene, ethylbenzene, and o-xylene) in soils, to determine the effects of BTEX concentrations on the population of fungi and bacteria in the soil, and to investigate the possible sources and spatial distribution of BTEX in the selected areas. The concentrations of BTEX were measured using a Gas Chromatograph (FID, ECD) in 9 contaminated and 3 control sites over 3 months. The spatial distribution of BTEX revealed that the highest concentrations were in the agricultural area (2.49±0.94 ppm) followed by industrial area (2.14 ±1.02 ppm) and the lowest in an urban area (1.32±0.44 ppm). BTEX assessment showed that the benzene concentration in all contaminated areas was above the recommended US EPA standard of 0.005 ppm (5 µg/kg). In addition, the mean concentrations of ethylbenzene were above the recommended U.S. EPA limit of 0.370 ppm in three areas; agricultural (0.76±0.61 ppm), in dustrial (0.89±0.68 ppm) and urban control (0.89±0.31 ppm). There was a significant difference in concentration of o-xylene between the study samples and control samples F (11, 24) = 5.374, P < 0.000. Pearson correlation showed a significant positive correlation between BTEX and total fungi (TF), r = 0.351. Pearson correlation also showed that o-xylene was significantly positively correlated with total fungi (TF), r = 0.331. The result showed a significant threat of benzene and ethylbenzene to soil health. Increased and regular monitoring is thus recommended to manage the increased concentrations of BTEX in future and reduce the adverse impacts of its effluence on soils and human health.