Browsing by Author "Wafula, Eliud N."

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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.
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.
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 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
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.
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.
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.
Isolation and Characterization of Bacteriocin-Producing Lactic Acid Bacteria from Mbithi: A Kenyan Traditional Fermented Porridge
(Journal of Harbin Engineering University, 2025-02-23) Wafula, Eliud N.; et.al
Introduction: Mbithi is a non-alcoholic, spontaneously fermented product that remains a traditional food cuisine in Kenya, valued for its nutritional properties. Lactic acid bacteria (LAB) are utilized in the food business as a starting culture, with their preservation properties linked to their ability to produce bacteriocins. Due to their eco-friendly properties, LAB's bacteriocins offer a viable solution to the health risks associated with chemical preservatives in the food industry. Objectives: This study presents results on isolating and characterizing bacteriocin-producing lactic acid bacteria from Mbithi. Methods: Lactic acid bacteria (LAB) were isolated using MRS and M17 agar. These isolates were then phenotypically characterized, including biochemical and physical tests. The isolates were screened for antimicrobial activity by agar well-diffusion assay, while genotypic characterization was performed based on the 16S rRNA gene sequence. Results: A total of 50 LAB strains were extracted. Of the fifty (50) isolates, 47 (94%) were selected due to their demonstration of gram-positive characteristics and catalase activity. Furthermore, 12 isolates were heterofermentative for they fermented glucose, whereas (35) isolates did not metabolize glucose (homofermentative). The results on salinity, acidity, and temperature demonstrated that most of the isolates tolerated the salinity with 6.5% of NaCl, acidic at pH 2.0 and pH 2.5 and temperature of 45°C. Nonetheless, none of the isolates withstood a temperature of 10℃. From the inhibition tests, we identified 10 candidate isolates, including three isolates—FP2 24, FP2 28, and FP22—that exhibited antagonism against all evaluated indicator pathogenic microorganisms. The three isolates exhibited inhibitory activity against E. coli, Bacillus subtilis, and Staphylococcus aureus, with inhibition zones of 21±1.41, 26±1.41, and 21±1.41, respectively, and a P-value of less than (P<0.05, P=0.000). The phylogenetic and Blast analyses indicated that the isolates were categorized into five clusters: Lactiplantibacillus, Levilactobacillus, Pediococcus, Weisella, and Leuconostoc, with the majority clustering within the Lactiplantibacillus genus, with similarities ranging from (95.1%-100%). Conclusions: The findings revealed potential isolates showing antagonistic activity against pathogenic indicators, suggesting their possible production of secondary metabolites. Despite this research presenting promising outcomes, further characterization is requested to get insights on probiotics properties for the usage of the isolates in preservatives in the food industry domains.
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
Isolation and Identification of Bacteriocin-Producing Bacillus spp from Rastrineobola argentea (Omena) with Activity against Bovine Mastitis Bacterial Pathogens
(Journal of Food Security, 2021-04-19) Wafula, Eliud N.; et.al
Rampant use of antibiotics has increased resistance of pathogenic bacteria in both animals and humans. This has triggered the investigation of novel antimicrobial agents produced by a bacterial strain of low virulence with antimicrobial activity with a wide range of clinical significance. This study sought to extract bacteriocins from Bacillus spp that were isolated and identified from Omena (Rastrineobola argentea) and to evaluate the in vitro antimicrobial effect of the obtained bacteriocin against bovine mastitis pathogens. Samples were collected from Lake Victoria using a completely randomized design method followed by isolation of the bacteriocin producing Bacillus spp. Characterization and identification of isolates was done by Gram staining, morphology and Biochemical tests which included catalase, nitrate reduction, methyl Red,-Voges-Proskauer, indole, motility and hydrogen sulphide, growth on Simmons citrate agar, triple sugar iron agar and starch hydrolysis. Antimicrobial activity was done using disc diffusion methods on the nutrient agar and zone of the inhibition measured after 24hours. An analytical profile index system (API 50CH BE, Biomerieux, Inc, France), was also used for identification. Molecular characterization was done by extracting genomic DNA using Qiagen DNA isolation Kit (Qiagen Germany) using the manufacturer's instructions. The gene encoding the 16S rRNA was amplified by PCR using universal bacterial primers pair combination of forwarding primer 27F forward (5′-AGA GTT TGA TCC TGG CTC AG-3′) and 1492R reverse, (5′-GGT TAC CTT GTT ACG ACT T-3′) about Escherichia coli gene sequence. A total of 60 pure isolates were obtained from Omena samples from Lake. Victoria. Morphological characteristics showed varied colour, form, shape and elevation of the pure colonies. About 54 isolates (90%) were gram-positive with spores, while 6 (10%) were gram-negative. Biochemical tests showed varied results among the bacterial isolates. 28 isolates showed antimicrobial activity on E. coli and S. aureus with inhibition measuring between 17-30mm. Analytical profile index system also showed that 20 isolates (71%) were identified as Bacillus subtilis, three isolates (11%) identified as Bacillus pumilus and five isolates (18%) Bacillus mycoides. The Blast analysis of the partial sequences showed100% of the strains of genus Bacillus within the Firmicutes in the domain bacteria. Twenty (20) isolates belong to Bacillus subtilis, Bacillus mycoides represent 18% (5 isolates) while Bacillus pumilus constituted 11% (3 isolates). This study contributes to understanding the use of bacteriocin in the control of diseases in dairy animal farming in Kenya.
Lactic Acid Bacteria from African Fermented Cereal-Based Products: Potential Biological Control Agents for Mycotoxins in Kenya
(Hindawi Journal of Toxicology, 2022-02-22) Wafula, Eliud N.; et.al
is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Cereals play an important role in global food security. Data from the UN Food and Agriculture Organization projects increased consumption of cereals from 2.6 billion tonnes in 2017 to approximately 2.9 billion tonnes by 2027. However, cereals are prone to contamination by toxigenic fungi, which lead to mycotoxicosis. e current methods for mycotoxin control involve the use of chemical preservatives. However, there are concerns about the use of chemicals in food preservation due to their effects on the health, nutritional quality, and organoleptic properties of food. erefore, alternative methods are needed that are affordable and simple to use. e fermentation technique is based on the use of microorganisms mainly to impart desirable sensory properties and shelf-life extension. e lactic acid bacteria (LAB) are generally regarded as safe (GRAS) due to their long history of application in food fermentation systems and ability to produce antimicrobial compounds (hydroxyl fatty acids, organic acids, phenyllactic acid, hydrogen peroxide, bacteriocins, and carbon dioxide) with a broad range of antifungal activity. Hence, LAB can inhibit the growth of mycotoxin-producing fungi, thereby preventing the production of mycotoxins. Fermentation is also an efficient technique for improving nutrient bioavailability and other functional properties of cereal-based products. is review seeks to provide evidence of the potential of LAB from African fermented cereal-based products as potential biological agents against mycotoxin-producing fungi.
MICROBIAL, CHEMICAL AND SENSORY PROPERTIES OF PINEAPPLE AND BEETROOT JUICE BLEND FERMENTED USING MIXED PROBIOTIC LACTIC ACID BACTERIA CULTURES (LACTOBACILLUS PLANTARUM AND L. RHAMNOSUS)
(African journal of food, Agriculture,Nutrition and development ajfand, 2025-11-06) Wafula, Eliud N.; et.al
The rising demand for functional foods has increased interest in probiotic products beyond traditional dairy sources, particularly among individuals with lactose intolerance, dairy allergies, or those adhering to plant-based diets. Fruit juices such as pineapple and beetroot offer promising non-dairy alternatives for delivering probiotic cultures. This study aimed to analyze the microbial, physicochemical, nutritional, and sensory acceptability profiles of pineapple and beetroot juice blends fermented with a mixed culture of probiotic lactic acid bacteria (Lactobacillus plantarum and Lactobacillus rhamnosus). Juice blends were prepared in varying pineapple-to-beetroot ratios: 90:10 (P90:B10), 80:20 (P80:B20) and 70:30 (P70:B30), alongside 100% pineapple (control-P) and 100% beetroot (Br) juices. All blends were pasteurized and inoculated with the probiotic cultures and fermented for 28 days, except the control-P and 100% Br treatment, which underwent spontaneous fermentation. Lactic acid bacteria (LAB) count analysis showed that all inoculated blends maintained probiotic viability (>7 log CFU/mL) for up to 21 days, with the P90:B10 blend maintaining viability up to 28 days. Yeast or mold growth was not detected in the probiotic blends up to day 21, whereas the control-P and 100%Br treatment exceeded yeast and mold count limits by day 14. Physicochemical analysis for all treatments revealed a significant increase in titratable acidity, accompanied by a decrease in pH and sugar content over the fermentation period in the inoculated blends (P90:B10, P80:B20, P70:B30). Significant differences P < 0.05 in vitamin C content were observed between the control-P and all other treatments on day 1. Among the three blends, P90:B10 achieved the highest overall consumer acceptability. Fermenting pineapple-beetroot juice blends with L. plantarum and L. rhamnosus mixed culture is a feasible approach to producing a safe, palatable, and nutritionally beneficial non-dairy probiotic beverage. The P90:B10 blend was optimal in supporting probiotic viability and achieving desirable consumer sensory attributes and, therefore, would be recommended for future commercialization as a probiotic non-dairy product.
Phenotypic and genotypic characterization of lactic acid bacteria isolated from spontaneously fermented vegetable amaranth
(African Journal of Food Science, 2021-05-25) Wafula, Eliud N.; et.al
Lactic acid bacteria (LAB) are Gram-positive, non-spore-forming, catalase-negative cocci or rod-shaped bacteria that produce lactic acid as a major fermentation product. They are also involved in the production of fermented foods. They have applications in industry and human health, such as food preservation and probiotics. The aim of this research was to isolate, characterize, and classify indigenous lactic acid bacteria from fermented vegetable amaranth, a leafy vegetable native to Africa. The isolates' 16S rRNA gene was amplified using bacterial universal primers 27F and 1492R. From fermented vegetable amaranth, a total of 15 LAB were isolated were grouped into the genera Lactobacillus, Lactococcus, and Weissella based on 16S rRNA gene analyses. Lactobacillus plantarum dominated vegetable amaranth fermentation, accounting for 60% of all isolates.
Potential Role of African Fermented Indigenous Vegetables in Maternal and Child Nutrition in Sub-Saharan Afric
(Hindawi International Journal of Food Science, 2021-12-15) Wafula, Eliud N.; et.al
Hunger and malnutrition continue to affect Africa especially the vulnerable children and women in reproductive age. However, Africa has indigenous foods and associated traditional technologies that can contribute to alleviation of hunger, malnutrition, and communicable and noncommunicable diseases. The importance of African indigenous vegetables is undeniable, only that they are season-linked and considered as “food for poor” despite their high nutritional contents. The utilization of African indigenous vegetables (AIVs) is hindered by postharvest losses and antinutrients affecting the bioavailability of nutrients. In Africa, fermentation is among the oldest food processing technologies with long history of safe use. Apart from extending shelf life and improving food organoleptic properties, fermentation of African indigenous vegetables (AIVs) is known to improve food nutritional values such as proteins, minerals, vitamins, and other beneficial phytochemicals. It can also increase bioavailability of various vitamins, minerals, and phytochemicals and increase synthesis of vital blood pressure regulators thus protecting against cardiovascular diseases and cancer and further helping fight certain malnutrition deficiencies. Some lactic acid bacteria (LAB) involved in food fermentation are known to produce exopolysaccharides with cholesterol-lowering, immunomodulator, antioxidant, and anticancer properties. Fermented foods (vegetables) are superior in quality and safety since most microorganisms involved in fermentation are good starter cultures that can inhibit the growth of foodborne pathogens and detoxify harmful compounds in foods. Thus, fermented foods can boost growth and well-being in children and women due to their higher nutritional contents. Therefore, fermentation of AIVs can contribute to the attainment of food and nutrition security especially among women and children who rely on these vegetables as a staple source of micronutrients and income. These benefits have a positive impact on the implementation of the second sustainable development goals and African Union agenda 2063. This review is aimed at shedding light on the potential of African fermented indigenous vegetables in combating maternal and child malnutrition in Sub-Sahara Africa
Prokaryotic diversity and composition within equatorial lakes Olbolosat and Oloiden in Kenya (Africa)
(ELSEVIER :www.sciencedirect.com/journal/current-research-in-microbial-sciences, 2021-12-26) Wafula, Eliud N.; et.al
Total community 16S rDNA was used to determine the diversity and composition of bacteria and archaea within lakes Olbolosat and Oloiden in Kenya. The V3-V4 hypervariable region of the 16S rRNA gene was targeted since it’s highly conserved and has a higher resolution for lower rank taxa. High throughput sequencing was performed on 15 samples obtained from the two lakes using the Illumina Miseq platform. Lakes Olbolosat and Oloiden shared 280 of 10,523 Amplicon Sequence Variants (ASVs) recovered while the four sample types (water, mi crobial mats, dry and wet sediments) shared 4 ASVs. The composition of ASVs in lake Olbolosat was highly dependent on Cu+, Fe2+, NH4+, and Mn2+, while L. Oloiden was dependent on Mg2+, Na+, Ca2+, and K+. All the alpha diversity indices except Simpson were highest in the dry sediment sample (EC1 and 2) both from lake Oloiden. The abundant phyla included Proteobacteria (33.8%), Firmicutes (27.3%), Actinobacteriota (21.2%), Chloroflexi (6.8%), Cyanobacteria (3.8%), Acidobacteriota (2.8%), Planctomycetota (1.9%) and Bacteroidota (1.1%). Analysis of similarity (ANOSIM) revealed a significant difference in ASV composition between the two lakes (r =0.191, p =0.048), and between the sample types (r =0.6667, p =0.001). The interaction network for prokaryotic communities within the two lakes displayed Proteobacteria to be highly positively connected with other microbes. PERMANOVA results suggest that temperature controls the functioning of the two ecosystems.
Screening and Identification of Diesel Biodegrading Bacteria Isolated From Petroleum Hydrocarbon Contaminated Garage Soils of Kericho County, Kenya
(International Journal of Microbiology, 2025-12-24) Wafula, Eliud N.; et.al
Despite the benefits of petroleum hydrocarbon as essential raw energy sources in many industries, they cause major global environmental pollution. Petroleum hydrocarbons pollutants are highly toxic and recalcitrant, making them dangerous and persistent over long periods in an ecosystem. However, oil contaminated soil is enriched with microorganisms that can uti lize petroleum products and hydrocarbons for their growth, nutrition, and metabolic activities. This study aimed to isolate and characterize hydrocarbons-degrading bacteria capable of degrading hydrocarbons in soil samples obtained from oil-polluted garage sites in Kericho County, Kenya. One hundred and ten (110) bacterial isolates were isolated after enrichment, with 67 of the isolates (60.9%) having visible petroleum diesel-degrading capability. The bacteria were characterized based on pheno typic characteristics and 16S rRNA gene sequence analyses. Forty-nine of the isolates were Gram negative rods, and majority (56) of the isolates reacted positively for catalase and negatively for oxidase (38), methyl red (59), and Voges Proskauer (65); 50.9% of the isolates tested positive for citrate utilization. More than half of the isolated bacteria (69.7%) demonstrated strong evidence of diesel degradation. Bacteria with moderate diesel degradation demonstration accounted for 18.2% of the isolates, while isolates with substantial diesel residues contributed 12.1%. Following 16S rRNA gene sequence analysis, the bacterial strains were identified as belonging to the genera Acinetobacter (8), Pseudarthrobacter (4), Corynebacterium (2), Gordonia (2), Athrobacter (2), Microbacterium (2), Acidivorax (1), Pseudoxanthomonas (1), Priestia (1), Cellulosimicrobium (1), Cupriavidus (1), Paenarthrobacter (1), Exiguobacterium (1), Shewanella (1), Stutzerimonas (1), and Pseudomonas (1). This study has demonstrated that garage soils with petroleum hydrocarbon contamination in Kericho County harbor a rich and diverse indigenous population of microbes with the ability to biodegrade diesel. The findings suggest potential application of these bacterial strains to facilitate the biodegradation of petroleum hydrocarbons.
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.
Taxonomical, functional, and cytopathological characterization of Bacillus spp. from Lake Magadi, Kenya, against Rhizoctonia solani Kühn in Phaseolus vulgaris L
(Journal of Basic Microbiology, 2023-05-24) Wafula, Eliud N.
A decline in common bean production and the ineffectiveness of synthetic chemical products in managing plant pathogens has led to exploiting Kenyan soda lakes as an alternative search for biocontrol agents. This study aimed to identify phylogenetically Bacillus spp. from Lake Magadi and their antagonistic activity against Rhizoctonia solani under in vitro and in vivo conditions. The 16 S ribosomal RNA (rRNA) subunit sequences of six bacterial strains isolated from Lake Magadi showed diversity similar to the Bacillus genus; Bacillus velezensis, Bacillus subtilis, and Bacillus pumilus. In vitro, antagonism showed varied mycelium inhibition rates of fungi in the coculture method. Enzymatic assays showed the varied ability of isolates to produce phosphatase, pectinase, chitinase, protease, indole‐3‐acetic acid (IAA), and hydrogen cyanide (HCD). The in vivo assay showed M09 (B. velezensis) with the lowest root mortality and incidence of postemergence wilt. Pre‐emergence wilt incidence was recorded as lowest in M10 (B. subtilis). Isolate M10 had the highest phenylalanine ammonia‐ lyase (PAL) for defense enzymes, while polyphenol oxidase (PPO) and peroxidase were recorded as highest in M09. For the phenolic content, M10 recorded the highest phenolic content. In conclusion, Lake Magadi harbors Bacillus spp, which can be used as a potential biocontrol of R. solani.