School of Pure and Applied Sciences

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Antibacterial Potency of Allium sativum, Psidium guajava, Zingiber officinale Roots against the Food Poisoning Strains (Escherichia coli 0157:H7 and Staphylococcus aureus)
(Tanzania Journal of Science, 2022-12-16) Mauti, Godfrey O.
Escherichia coli 0157:H7 and Staphylococcus aureus are notorious food poisoning bacteria of great effect on human health. This study determined the phytochemical constituents of ethanolic, vacuum liquid chromatography (VLC) filtrates of Allium sativum (garlic), Psidium guajava (guava), Zingiber officinale (ginger) and their antibacterial activities on E. coli 0157:H7 and S. aureus. In a laboratory-based controlled experiment, the antibacterial and inhibitory activities of the VLC filtrates in doses of 0.01, 0.02, 0.04, and 0.08g/mL were investigated on E. coli 0157:H7 and S. aureus using the agar well diffusion method and compared with a standard antibiotic. The indices of the zone of inhibition on the agar plates were subjected to analysis of variance (p = 0.01). Phytochemical analysis revealed a high concentration of glycosides, steroids, tannins, terpenoids, and the absence of flavonoids in A. sativum. P. guajava root contained a high concentration of glycosides, steroids, tannins, and terpenoids. Z. officinale possessed a high concentration of alkaloids, glycosides, flavonoids, steroids, and terpenoids. Statistically, 0.02 g/mL of Z. officinale (12.0 mm) showed a significant result to 0.04g/mL of A. sativum (14mm) at p = 0.0049 and a higher inhibition index to 0.08g/mL of P. guajava. Inhibition by 0.02g/mL of P. guajava (8.8mm) was advanced than 0.04g/mL of A. sativum (6.3 mm) on S. aureus. Recommendable inhibition of 29.3 mm and 24.0 mm on E. coli 0157:H7 and S. aureus, respectively, were expressed by 0.08 g/mL Z. officinale, which was significant to the standard 0.04 g/mL of Neomycin (Positive control) at p = 0.0067. This study indicated a reliable antibacterial activity by Z. officinale than A. sativum and P. guajava, which might have been due to the high concentration of alkaloids and flavonoids. Nevertheless, A. sativum, P. guajava, and Z. officinale are normally used as fruit and food additives in the human diet, thus can be combined to prevent food poisoning by E. coli 0157:H7 and S. aureus and their exotoxins.
Antimicrobial Activity and Characteristics of Bacteriocin Producing Bacillus subtilis against Mastitis Pathogens
(American Journal of Food Science and Technology, 2021-04-20) Wafula, Eliud N.; et.al
The use of drugs and antibiotics has increased the resistance of pathogenic bacteria in both animals and humans. This has been a significant problem and therefore triggers the investigation of novel antimicrobial agents produced by a bacterial strain of low virulence and having antimicrobial activity with a wide range of clinical significance. The use of bacteriocin has been extensively used in food industries, animals, and pharmaceutical industries. This is because it has been linked to antimicrobial activity, which has specific self-protection mechanisms. This study sought to evaluate antimicrobial activity and characteristics of bacteriocin producing Bacillus subtilis against Mastitis pathogens. For the screening of the isolates for bacteriocin properties against mastitis pathogens, antimicrobial activity was done using well diffusion methods on the nutrient agar. The results were obtained after 24hours and 48hours. Physiochemical characterization of the bacteriocin from Bacillus subtilis was determined at different temperatures of 60°C to 121°C for 15 minutes and monitor the effect of the temperature. The bacteriocin was also prepared at different pH (3-9) and incubated at room temperature; each sample's residual activity was determined against the indicator organisms. Metal ions (Cu2+, Zn2+, and Fe2+) on crude bacteriocin activity were determined to assess the residual antimicrobial activity by agar well diffusion assay. The results showed that bacteriocins from Bacillus subtilis were effective against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumonia. Physiochemical characterization showed that bacteriocin from different isolates had no inhibition from pH 3-5 and varied inhibition from pH 6-9 across the test organisms' isolates. On the temperature, crude bacteriocins at a temperature of 50°C to 60°C showed no activity loss based on initial activity. As temperature increases to 70°C to 80°C, there is reduced the bacteriocin activity of about 20%. 100°C had a 40% loss of the bacteriocin activity and 121°C with more than 50% loss of the activity. On metal ions, Cu2+, Fe2+, Zn2+ had a varied effect on bacteriocin activity against test organisms.
Application of Asymmetric-GARCH Type Models to The Kenyan Exchange Rates
(EJ-MATH, European Journal of Mathematics and Statistics, 2023-08-31) Wagala , Adolphus; et.al.
Modelling and forecasting the volatility of a financial time series has become essential in many economic and financial applications like portfolio optimization and risk management. The symmetric-GARCH type models can capture volatility and leptokurtosis. However, the models fail to capture leverage effects, volatility clustering, and the thick tail property of high-frequency financial time series. The main objective of this study was to apply the asymmetric-GARCH type models to Kenyan exchange to overcome the shortcomings of symmetric-GARCH type models. The study compared the asymmetric Conditional Heteroskedasticity class of models: EGARCH, TGARCH, APARCH, GJR-GARCH, and IGARCH. Secondary data on the exchange rate from January 1993 to June 2021 were obtained from the Central Bank of Kenya website. The best fit model is determined based on parsimony of the Akaike Information Criterion (AIC), Bayesian Information Criterion (BIC), Log Likelihood criterion, and minimisation of prediction production errors (Mean error [ME] and Root Mean Absolute error [RMAE]). The optimal variance equation for the exchange rates data was APARCH (1,1) - ARMA (3,0) model with a skewed normal distribution (AIC = -4.6871, BIC = -4.5860). Volatility clustering was present in exchange rate data with evidence of the leverage effect. Estimated Kenya’s exchange rate volatility narrows over time, indicating sustained exchange rate stability
Assessment of Ni Toxicity to Fungi and Bacteria in Oil Tainted Soils in Greater Port Harcourt Area, Nigeria
(J. Appl. Sci. Environ. Manage., 2021-07-01) Wanjala M. P, et al.
Intensified urbanization and industrialization are rapidly triggering the release of pollutants to the environment. This study determined the extent of soil contamination with Nickel (Ni) in oil mining areas and its effect on the levels of Ni tolerance by fungi and bacteria. The total CFUs/g of soil were enumerated after a culture period of 7 days at 28°C and LC50 was determined using probit and regression analysis. The mean values of Ni were 1.38±0.23 in industrial area, 1.41±0.36 ppm in agricultural area and 1.02±0.64 in urban area. The mean values of Total Petroleum Hydrocarbon (TPH) were 4,405.46 ppm in industrial area, 55.65 ppm in agricultural area and 1,304.53 ppm in urban area. Nickel’s peak concentration indicating growth of both fungi and bacteria at 150 ppm. There was significant difference (p ≤ 0.000) in the mean levels of LC50 for fungi among the study sites. There was no significant correlation between the concentration of TPH in soil and LC50 of fungi (r = -0.169) and bacteria (r = 0.042). In conclusion, TPH influenced the levels of fungi and bacteria tolerance to Ni in soils. Moreover, it was observed that LC50 can be a reliable method for monitoring chemically resistant microorganisms directly in the environment to improve the use of microorganisms for the bioremediation of oil contaminated soils and in monitoring of antibiotic resistant microorganisms in natural ecosystems
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.
Characterization of Chemically Activated Carbons Produced from Coconut and Palm Kernel Shells Using SEM and FTIR Analyses
(Science Publishing Group, 2021-06-30) Wanjala , Paul Muyoma
Chemically activated carbons generated from coconut (CS) and palm kernel (PKS) shells soaked with 1M solution of K2CO3 and NaHCO3 at 1000°C using the Carbolite Muffle Furnace were examined using scanning electron microscopy (SEM) and Fourier Transformation Infrared Spectroscopy (FTIR). Results from the FTIR analyses revealed that the coconut and palm kernel shells manufactured were successfully chemically activated. Several chemical compounds and functional groups, such as hydroxyl groups, carbonyl groups, ethers, alkanes, alkenes, and aromatic groups, were detected in chemically activated carbon produced from palm kernels and coconut shells as proof of the lignocellulose structure in them. Chemically activated carbon made from coconut shells exhibited nine distinct spectra, while palm kernel shells exhibited six distinct spectra. The pores were larger in the chemically activated carbons produced at a higher temperature (1000°C), demonstrating that temperature is an essential process parameter in the development of surface porosity in chemically activated carbons. The chemical carbonization activation methods used provided porosity, a large surface area, and precise morphology for absorption in both the coconut and palm kernel shells, indicating that they can be turned to high-performance adsorbents. Both organic and inorganic contaminants can be removed from the environment using the chemically activated carbons produced.
Characterization of culturable microbial community in oil contaminated soils in Greater Port Harcourt Area, Nigeria
(Academic Journals, 2020-09-17) Wanjala , Muyoma Paul
The study investigated microbial population dynamics in soils of Greater Port Harcourt Area, Nigeria. The study involved the quantification of petroleum pollutants and the enumeration and characterization of culturable fungi and bacteria. Gas Chromatograph FID method was used to quantify total petroleum hydrocarbons (TPH) in the soil while morphological and biochemical tests were used to characterize the microorganisms. The highest TPH was 9,759.37±883.36 ppm which exceeded the Department of Petroleum Resources’ (DPRs’) intervention value of 5,000 ppm. The percentage of hydrocarbon utilizing fungi (% HUF) ranged between 1.93±0.57 and 66.55±5.60 which were observed in sites A1 (Aluu) and CA (Agricultural control), respectively. The percentage of hydrocarbon utilizing bacteria (% HUB) ranged between 0.12±0.01 and 7.89±1.25 which was observed in sites A3 (Emuoha) and CU (Urban control), respectively. The most prevalent bacterial species includes Bacillus subtilis, Micrococcus lylae, Staphylococcus aureus, Bacillus cereus and Alcaligen faecalis. The most prevalent HUB isolate was Bacillus subtilis. The most prevalent fungal isolates were Aspergillus niger, Aspergillus flavus and Candida torulopsis. A. niger was the most prevalent among the HUF isolates which was identified in 12 sites. It was concluded that the study sites harboured TPH degrading microorganisms that are appropriate for bioremediation of TPH polluted sites.
DETERMINANTS OF CORPORATE CASH HOLDINGS: EVIDENCE FROM PRIVATE MANUFACTURING FIRMS IN KENYA
(International Journal of Advanced Research in Management and Social Sciences, 2015-06) Orwa, George O.; Kariuki, Samuel Nduati; Namusonge, Gregory S.
Cash is an important requirement to ensure continued operations, yet excessive cash holdings might result in many problems which include; higher opportunity costs of holding cash, cash abuse, a tool for obtaining the controlled self-interests and the higher agency costs. The study established thatthere is a negative and insignificant linear relationship between growth opportunities and corporate cash holdings. The study also revealed that leverage is a significant positive determinant of corporate cash holdings in line with the precautionary motive. In regard to firm size, the study findings indicate that firm size positively determines corporate cash holding. Further, the study revealed that there is a negative linear relationship between likelihood of financial distress and cash holdings.The findings also confirmed a positive relationship between cash flow variability and corporate cash holdings.The study therefore concludes that; leverage, firm size, likelihood of financial distress and cash flow variability determine corporate cash holdings among private manufacturing firms in Kenya
Effect of lactic acid bacteria fermentation on nutrients and anti-nutrients of African black nightshade and African spider plant
(ELSEVIER, 2023-06-23) Wafula, Eliud N.; et .all
African black nightshade is a leafy vegetable consumed in many parts of Africa. African spi- der plant is also a very important indigenous leafy vegetable consumed all around Africa. Both the African black nightshade and African spider plant are popular despite their te- dious preparation techniques which involve boiling and discarding the first water or a lengthy boiling duration to remove bitterness. However, this preparation technique reduces heat-labile and water-soluble nutrients. Fermentation can be a better alternative process- ing technique since it has been observed that fermented products have better nutritional content and increased safety. However, there is still limited literature on the effect of fermentation on the nutrients and anti-nutrients content of these vegetables. This study aimed to ferment African black nightshade and African spider plant using Lactobacillus fermentum and Lactococcus lactis cultures and determined the effect of the fermentation on their nutrients and anti-nutrients content. Both vegetables were submerged in a 3% sugar and 3% salt brine solution. Total ash, crude proteins and crude fibres significantly increased in starter culture inoculated vegetables. However, both β-carotene and ascorbic acid were slightly reduced in all fermented batches. Anti-nutrients were significantly re- duced in all fermented batches. In conclusion, lactic acid fermentation of these vegetables demonstrated the ability to maintain or increase nutrients while reducing of anti-nutrients.
Effect of lactic acid bacteria fermentation on nutrients and anti-nutrients of African black nightshade and African spider plant
(ELSEVIER, 2023-06-14) Wafula, Eliud Nalianya; et.al
African black nightshade is a leafy vegetable consumed in many parts of Africa. African spi der plant is also a very important indigenous leafy vegetable consumed all around Africa. Both the African black nightshade and African spider plant are popular despite their te dious preparation techniques which involve boiling and discarding the first water or a lengthy boiling duration to remove bitterness. However, this preparation technique reduces heat-labile and water-soluble nutrients. Fermentation can be a better alternative process ing technique since it has been observed that fermented products have better nutritional content and increased safety. However, there is still limited literature on the effect of fermentation on the nutrients and anti-nutrients content of these vegetables. This study aimed to ferment African black nightshade and African spider plant using Lactobacillus fermentum and Lactococcus lactis cultures and determined the effect of the fermentation on their nutrients and anti-nutrients content. Both vegetables were submerged in a 3% sugar and 3% salt brine solution. Total ash, crude proteins and crude fibres significantly increased in starter culture inoculated vegetables. However, both β-carotene and ascorbic acid were slightly reduced in all fermented batches. Anti-nutrients were significantly re duced in all fermented batches. In conclusion, lactic acid fermentation of these vegetables demonstrated the ability to maintain or increase nutrients while reducing of anti-nutrients
Effect of Lactic Acid Fermentation on Phytochemical Content, Antioxidant Capacity, Sensory Acceptability and Microbial Safety of African Black Nightshade and African Spider Plant Vegetables
(BACTERIA MDPI, 2023-02-11) Wafula, Eliud N.; et.al
Traditional preparation of African indigenous vegetables (AIVs) such as African black nightshade (Solanum nigrum) and African spiderplant (Cleome gynandra) involves either boiling and discarding the first water or lengthy boiling. Fermentation is considered a better alternative processing technique due to the enhanced retention of phytochemical contents and sensory properties. However, little is known about the impact of lactic acid fermentation on the phytochemical content, antioxidant capacity, sensory acceptability and microbial safety of the African black nightshade and African spiderplant. This study aimed to ferment AIVs using combined starter cultures (Lactobacillus fermentum and Lactococcus lactis) and further determine their effect on the phytochemical content (phenolic compoundsandflavonoids), antioxidantcapacity, sensory acceptability and microbial safety of the vegetables. There was a marked increase in phenol and flavonoid contents in all fermented vegetables (p < 0.05). The starter-culture-inoculated African black nightshade, while flavonoid content was 10.6 mg/g QE (quercetin equivalent) in the same. Starter-culture-inoculated AIVs presented significantly higher antioxidant capacity with a 60–80% radical scavenging activity compared to levels in uninoculated batches (p < 0.05). Fermented vegetables were more liked than the boiled vegetables and were microbiologically safe. In conclusion, lactic fermentation of AIVs increased phytochemical contents (phenolic compounds and flavonoids), maintained antioxidant capacity and improved product safety and sensory acceptability. Therefore, fermentation and consumption of the African indigenous vegetables are to be encouraged
Evaluating the Predictive Ability of Seasonal Autoregressive Integrated Moving Average (SARIMA) Models When Applied to Food and Beverages Price Index in Kenya
(EJ-MATH, European Journal of Mathematics and Statistics, 2022-04-08) Wagala, Adolphus; Wanjuki, Teddy M.
Price instability has been a major concern in most economies. Kenya's commodity markets have been characterized by high price volatility affecting investment and consumer behaviour due to uncertainty on future prices. Therefore, precise forecasting models can help consumers plan for their expenditure and government policymakers formulate price control measures. Due to the seasonality of Kenya's food and beverage price indices, the current study postulates that the Seasonal Autoregressive Integrated Moving Average (SARIMA) model can best be the best fit model for the data. The study used secondary data on Kenya's monthly food and beverage prices index from January 1991 to February 2020 to examine the predictive ability of the possible SARIMA models based on the minimisation of the Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC). A first-order differenced SARIMA (1,1,1) (0,1,1)12 minimized these model evaluation criteria (AIC = 1818.15, BIC =1833.40). The cross validation test results of 6, 12, 18, 24, 30, and 36 step-ahead forecasts demonstrated that SARIMA models are unstable for use in forecasting over a long-time period with a tendency of increasing prediction errors with an increase in the forecast period. It is anticipated that the findings of the current study will provide necessary valuable information to the policymakers and stakeholders to understand future trends in commodity price.
Evaluation of the Effects of Cadmium in Soil on the LC50 of Soil Bacteria and Fungi for Environmental Monitoring
(J. Appl. Sci. Environ. Manage., 2021-05-07) WANJALA, MP;
Contamination of soil with heavy metals by is currently of global concern. Cadmium (Cd) is one of the metals of concern. In the current study, LC50 of Cd to soil bacteria and fungi was used to assess the impact of anthropogenic activity in development of Cd tolerance in soil microorganisms. Levels of Bio-physicochemical parameters in soil were determined. Results show that the concentration of Total Petroleum Hydrocarbon (TPH) and Cd in soil ranged between 5.09±0.33 to 9261.94±287.67, and 0.023±0.015 to 0.057±0.012 ppm respectively. There was significant difference (p = 0.001) in LC50 for fungi between the study and control samples. Pearson correlation showed that there was significant relationship (r = 0.30) between LC50 for bacteria and TPH. There was significant difference (p = 0.017) in LC50 values among the study and control samples for fungi. Anthropogenic activities influenced the concentrations of TPH soil but did not influence levels of Cd.
Extracts of Jamun seeds inhibited the growth of human (Hep‑2) cancer cells
(Journal of Cancer Research and Therapeutics | Published by Wolters Kluwer - Medknow, 2023-04-07) . Mauti , Godfrey O
Introduction: In the last century, the human laryngeal epithelioma has become a life‑threatening disease leading to a high rate of mortality worldwide. The current investigation is focusing on the antiproliferative effect of Eugenia jambolana seed extracts against Hep‑2 cancer cells. Methods: The active compounds from the seeds of E. jambolana were extracted by the decoction extraction method using acetone, ethanol, and methanol. The filtrates from the different solvents were subjected to liquid‑liquid separation before drying by a rotary evaporator. In various doses, the crude extracts and carcinoma were subjected to a methylthiazolyl diphenyl tetrazolium bromide assay. Cell viability was determined under ultraviolet visualization at an absorbance of 540 nm. The data of the viable cells were subjected to analysis of variance at P ≤ .01. Results: Crude compounds of E. jambolana seeds extracted by acetone, methanol, and methanol extract had an anticarcinoma effect. Among the extracts, methanol extract possessed a recommendable anti‑carcinoma effect compared to acetone and ethanol crude extracts. At a concentration of 125 µg/mL, the crude extracts of methanol, acetone, and ethanol destroyed 49.57, 35.01, and 27.67 carcinomas, respectively. The concentration of 31.25 µg/mL of acetone extract and 125 µg/mL of ethanolic extract affected 28.11 and 27.67 carcinomas, respectively. Conclusions: E. jambolana seeds possess anticarcinoma potency and thus can be administered in the reduction of proliferative carcinoma. The study recommended further studies which will involve the elution of pure compounds from the methanol extract of E. jambolana that possess antitumour and antiproliferative activity against Hep‑2 cell lines.
Fermentation of African nightshade leaves with lactic acid bacterial starter cultures
(International Journal of Food Microbiology, 2021-01-04) Wafula, Eliud N.; et.al
The interest in the consumption of African indigenous leafy vegetables increased in African countries, e.g. Kenya, within the last years. One example of African indigenous leafy vegetables is African nightshade (Solanum sca brum) which is nutritious, rich in proteins and micronutrients and therefore could contribute to a healthy diet. African nightshade has several agricultural advantages. However, the most important disadvantage is the fast perishability which leads to enormous post-harvest losses. In this study, we investigated the fermentation of African nightshade as a post-harvest processing method to reduce post-harvest losses. The two lactic acid bac terial starter strains Lactiplantibacillus plantarum BFE 5092 and Limosilactobacillus fermentum BFE 6620 were used to inoculate fermentations of African nightshade leaves with initial counts of 106–107 cfu/ml. Uninoculated controls were conducted for each fermentation trial. Fermentations were performed both in Kenya and in Ger many. The success of the inoculated starter cultures was proven by the measurement of pH values and deter mination of lactic acid concentration. Lactobacilli strains dominated the microbiota of the starter inoculated samples in contrast to the non-inoculated controls. This was supported by classical culture-dependent plating on different microbiological media as well as by the culture-independent molecular biological methods denaturing gradient gel electrophoresis and 16S rRNA gene high-throughput amplicon sequencing. We could demonstrate that the use of the selected starter cultures for fermentation of African nightshade leaves led to controlled and reliable fermentations with quick acidification. Thus, controlled fermentation with appropriate starter cultures is a promising method for post-harvest treatment of African nightshade leaves.
Forecasting Commodity Price Index of Food and Beverages in Kenya Using Seasonal Autoregressive Integrated Moving Average (SARIMA) Models
(EJ-MATH, European Journal of Mathematics and Statistics, 2021-12-01) Wagala, Adolphus; Muriithi , Dennis K.
Price stability is the primary monetary policy objective in any economy since it protects the interests of both consumers and producers. As a result, forecasting is a common practice and a vital aspect of monetary policymaking. Future predictions guide monetary and fiscal policy tools that that be used to stabilize commodity prices. As a result, developing an accurate and precise forecasting model is critical. The current study fitted and forecasted the food and beverages price index (FBPI) in Kenya using seasonal autoregressive integrated moving average (SARIMA) models. Unlike other ARIMA models like the autoregressive (AR), Moving Average (MA), and non-seasonal ARMA models, the SARIMA model accounts for the seasonal component in a given time series data better forecasts. The study relied on secondary data obtained from the KNBS website on monthly food and beverage price index in Kenya from January 1991 to February 2020. R-statistical software was used to analyze the data. The parameter estimation was done using the Maximum Likelihood Estimation method. Competing SARIMA models were compared using the Mean Absolute Error (MAE), Mean Absolute Scaled Error (MASE),.and Mean Absolute Percentage Error (MAPE). A first-order differenced SARIMA (1,1,1) (0,1,1)12 minimized these model evaluation criteria (AIC = 1818.15, BIC =1833.40). The forecasting ability evaluation statistics MAE = 2.00%, MAPE = 1.62% and MASE = 0.87%. The 24-step ahead forecasts showed that the FPBI is unstable with an overall increasing trend. Therefore, the monetary policy committee ought to control inflation through monetary or fiscal policy, strengthening food security and trade liberalization.
IDENTIFICATION AND CHARACTERIZATION OF LACTIC ACID BACTERIA ISOLATED FROM SPONTANEOUSLY FERMENTED AFRICAN NIGHTSHADE (SOLANUM SCABRUM) LEAVES
(Journal of microbiology,Biotechnology and Food science (JMBFS), 2025-10-01) Wafula, Eliud N.; et.al
African nightshade (Solanum scabrum) is one of the most commonly consumed indigenous leafy vegetables in most parts of Sub-Saharan Africa. The vegetable is an excellent source of beta-carotene, vitamin A, C, E, iron, iodine, zinc, potassium, and protein, making it one of the most essential foods in addressing the malnutrition challenge among people experiencing poverty. This study focused on isolating, characterizing, and identifying dominant lactic acid bacteria (LAB) in naturally fermenting African nightshade leaves. The identification of LAB involved morphological, phenotypic, and molecular methods, including 16S rRNA gene sequencing. A total of 24 LAB strains were isolated and identified through phenotypic and 16S rRNA gene analyses. African nightshade fermentation was dominated by five genera of lactic acid bacteria: Lactiplantibacillus plantarum (38%), Leuconostoc spp (33%), Levilactobacillus brevis (13%), Weissella spp (13%) and Lactococcus lactis (3%). The findings reveal a rich and diverse community of LAB in fermented African nightshade, underscoring its potential as a natural reservoir of beneficial microorganisms. These LAB strains could have significant commercial and industrial potential, especially as starter cultures and probiotics in the production of fermented foods.
Impact of Nitrogen Fertilizer Use on Soil Ecosystem Integrity in the Greater Port Harcourt Region, Nigeria
(Science Publishing Group, 2021-10-05) Wanjala , Muyoma Paul
Fertilizers are used to increase crop yields in agriculture but can affect the integrity of soil ecosystems if misused. The present study was conducted to observe the impact of inorganic fertilizers in selected soils in Greater Port Harcourt Area on soil microbial population, in addition, the association between soil microbial population and Lethal Concentration 50 (LC50) was observed. Microbial communities and LC50 values were determined using normal analytical procedures. The study showed various fertilizer types that altered soil microbial population and LC50 values. For agricultural areas the maximum NPKB mean value was 0.70±0.76 ppm which was higher than the mean value of the control location of 0.23±0.00 ppm. Urea tolerant fungi’s (UREAF's) LC50 mean value was 0.43±0.09 ppm in the agricultural area as compared to the control with a mean value of 0.46±0.00 ppm. Industrial and urban areas had significantly different mean values of 0.29 ± 0.19 ppm and 0.18±0.01 ppm and 0.23 ± 0.06 ppm and 0.23 ± 0.060.17 ± 0.010.17 ± 0.010.17 ± 0.01 ppm respectively (p = 0.001). This research concluded that the application of UREA and NPK fertilizers in study area soils lowered the pH of soils in A1, A2 and A3 agricultural sites. Application of UREA and NPK fertilizers in soils of the study areas increased the population of microorganisms in threshold concentrations but was detrimental for NPK and UREA fertilizers at concentrations of 1.50% or above. Further findings showed that microorganisms were more tolerant of NPK and UREA fertilizers in agricultural areas compared to urban and industrial areas which showed higher LC50 values. This research concludes that fertilizers used in the study areas were related to soil microorganisms developing tolerance to NPK and UREA. Farmers should observe application of the recommended professional quantities of fertilizers to ensure the sustenance of the soil ecosystem integrity.
Isolation and Characterization of Bacillus velezensis from Lake Bogoria as a Potential Biocontrol of Fusarium solani in Phaseolus vulgaris L.
(BACTERIA MDPI, 2022-11-17) Wafula, Eliud N.; et.al
The common bean (Phaseolus vulgaris L.) is a significant vegetable crop, grown because it is a rich source of protein, carbohydrates, and vitamin B complex. Fusarium solani and Rhizoctonia solani are the most widely known pathogens contributing to large yield losses for this crop. The use of cultural and chemical control practices has been ineffective. Therefore, a sustainable, affordable, and effective control method is urgently required. In this study, we aimed to isolate and characterize Bacillus velezensis from Lake Bogoria as a potential biocontrol agent for Fusarium solani. Bacteria were isolated from soil and sediments using the serial dilution technique. Molecular characterization was performed using the 16S rRNA gene. A total of 13 bacteria were isolated from soil and sediments. Based on the partial sequences, BLAST analysis showed two isolates, B20 (Bacillus velezensis strain QH03-23) and B30 (Bacillus velezensis strain JS39D), belonging to Bacillus velezensis. Other isolates were identified as Bacillus tequilensis, Brevibacillus brevis, Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus licheniformis. The effectiveness of their antifungal properties was determined via co-culturing, and wefoundmycelial inhibition rates of 28.17% (for B20) and 33.33% (for B30) for the Fusarium solani isolates. The characterization of the Bacillus velezensis strain revealed that they were Gram-positive and grew well at pH 7.0 and 8.5, although growth was recorded at pH 5.0 and 10.0. In terms of temperature, the optimal temperature conditions were 30−35 ◦C, with an optimum salinity of 0–0.5 M NaCl. When these isolates were tested for their ability to produce secondary metabolites, they were found to produce phosphate, pectinase, chitinase, protease, indole-3- acetic acid (IAA), and hydrogen cyanide (HCD), making them potential biocontrol agents.
Isolation and Characterization of Bacteria from Lakes Olbolosat and Oloiden, Kenya
(African Journal of Microbiology Research, 2021-01-26) Wafula, Eliud N.; et.al
There is still unexplored reservoir of microorganisms from sediments and water within Lakes Olbolosat and Oloiden using culture dependent technique. The current study compares bacterial diversity within Lake Olbolosat a freshwater lake and Lake Oloiden a saline alkaline lake. Out of 60 isolates obtained from sediments and water samples, 35 were from Lake Olbolosat and 25 from Lake Oloiden. Microbial count ranged between 0-1.75× 105 cfu/ml from both lakes. There was a significant difference between bacterial density and sampling points (p<0.001, F=6.667), 58 were Gram-positive and 2 Gram-negative. Fifty-five isolates that were rod-shaped, 3 were cocci and 2 filamentous. There was excellent growth of isolates at an optimum growth pH range of 6-10, a temperature range of 25-30°C and a salinity range of 0-5%. There was significant difference at p<0.001 for bacterial growth within physiological parameters. The isolates utilized skimmed milk, starch, olive oil, cellulose powder and xylan, hence the production of extracellular enzymes. There was antimicrobial activity against Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli, Staphylococcus aureus and Candida albicans by bacterial isolates. BLAST analysis of partial sequences showed there were 4 different phyla. Firmicutes scored 77% closely affiliated with 20 strains, Actinobacteria scored 15% closely affiliated with 4 strains, Proteobacteria and Bacteroidetes scored 4% affiliated with 1 strain each. Novel bacteria from this study could provide insights into their diversity and biotechnological applications.