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Microbial gamma-aminobutyric acid synthesis: a promising approach for functional food and pharmaceutical applications
(Letters in Applied Microbiology, 2024) Fashogbon, Racheal Oluwayemisi; Samson, Oyindamola John; Awotundun, Theresa Abimbola; Olanbiwoninu, Afolake Atinuke; Adebayo-Tayo, Bukola Christiana
Gamma-aminobutyric acid (GABA) is a non-protein amino acid that is a main inhibitory neurotransmitter in the mammalian central nervous system. This mini-review emphasis on the microbial production of GABA and its potential benefits in various applications. Numerous microorganisms, including lactic acid bacteria, have been identified as efficient GABA producers. These microbes utilize glutamate decarboxylase enzymes to convert L-glutamate to GABA. Notable GABA-producing strains include Lactobacillus brevis, Lactobacillus plantarum, and certain Bifidobacterium species. Microbial GABA production offers numerous benefits over chemical synthesis, including cost-effectiveness, sustainability, and the potential for in situ production in fermented foods. Recent research has optimized fermentation conditions, genetic engineering approaches, and substrate utilization to enhance GABA yields. The benefits of GABA extend beyond its neurotransmitter role. Studies have shown its potential to reduce blood pressure, assuage anxiety, improve sleep quality, and improve cognitive function. These properties make microbial GABA production particularly attractive for developing functional foods, nutraceuticals, and pharmaceuticals. Future research directions include exploring novel GABA-producing strains, improving production efficiency, and investigating additional health benefits of microbially produced GABA.
Probiotic potential of riboflavin-overproducing Bacillus subtilis ACU-I163MR and ACU-I11MR, isolated from fermented African locust beans
(Microbiology Society, 2025) Awotundun, Theresa; Olanbiwioninu, Afolake Atinuke
Riboflavin (vitamin B2) is a water-soluble compound that plays an important role in multiple cellular functions. This study evaluates the probiotic potential of riboflavin-overproducing Bacillus subtilis strains isolated from fermented African locust beans. After strain improvement, B. subtilis ACU-I11MR and ACU-I163MR were selected due to their higher riboflavin production (0.01905±0.0005 mg l−1 to 0.0259±0.0077 mg l−1 and 0.0195±0.0054 mg l−1 to 0.0267±0.0013 mg l−1, respectively). Their safety was confirmed through haemolytic assay, antibiotic susceptibility tests and the absence of gelatinase and biogenic amine activity. Probiotic potential was assessed via in vitro assays including resistance to low pH, bile salts, phenol, temperature and NaCl; auto-aggregation; cell hydrophobicity; biofilm formation; antibacterial activity; and enzyme and exopolysaccharide production. Both strains were non-haemolytic and negative for gelatinase and biogenic amine activity. They showed significant viability at pH 2 (survival 85.05; 87.09%), 1% bile salts (survival 88.82; 87.64%) and 0.5% phenol (survival 48.80; 59.52%), respectively. ACU-I11MR was susceptible to 9 out of 12 antibiotics, while ACU-I163MR was 100% susceptible. The strains demonstrated strong cell surface adhesion and auto-aggregation and inhibited several pathogenic bacteria. They produce amylase, protease and exopolysaccharide and thrive under various temperature and NaCl conditions. B. subtilis ACU-I163MR, showing superior probiotic potential, could be a promising candidate for developing riboflavin-enriched Bacillus-fermented functional foods.
Antimicrobial Resistance of Tomato-Spoiling Microorganisms from Ajegunle Market, Oyo Town, Oyo State, Nigeria
(Ajayi Crowther Journal of Pure and Applied Sciences, 2025) Olanbiwoninu, Afolake Atinuke; Aponjolosun, Babalola Sunday; Obanisola, Peace Olayemi
Pathogenic bacteria and fungi associated with tomato spoilage have the tendency of harbouring antimicrobial resistance genes that can pose significant health threats to consumers, hence the need to ascertain their antibiotic sensitivity. Five spoilt tomato samples were purchased from five different tomato sellers in Ajegunle market, Oyo Town, Oyo State, Nigeria. Isolation was carried out using the pour plate method. The antibiogram of selected antibiotics and antifungal drugs against the bacteria and fungi isolates was determined using the diffusion disk technique. Colony count for bacteria ranged from 1.0 x 103 – 6.3 x 103 CFU/mL on Nutrient agar and 1.0 x 103 – 9.6 x 103 CFU/mL on MacConkey agar while the fungal count ranged from 2.2 x 105 – 5.1 x 105 CFU/mL on potato dextrose agar. The bacteria identified were Staphylococcus aureus, Aeromonas veronii, Bacillus cereus, B. brevis, B. pumilus, B. licheniformis, B. subtilis, Corynebacterium xerosis, Corynebacterium kutscheri and Lactobacillus casei with B. licheniformis being the most prevalent. Fungal isolates identified were: Saccharomyces cerevisiae, Rhizopus spp. and Fusarium spp. with Saccharomyces cerevisiae being the most prevalent. Most of the Gram-positive bacteria were resistant to Azithromycin (87.5%), Gentamycin (90.7%), Ofloxacin (93.7%) and Erythromycin (93.7%) while Aeromonas veronii was resistant to Gentamycin, Levofloxacin, Ofloxacin and Nitrofurantoin at 50% respectively, while Fusarium species showed resistance against Griseofulvin. The bacterial isolates' multi-antibiotic resistance (MAR) index ranged from 0.3 to 0.8. The resistance of the isolated microorganisms to commercial drugs could be risky to public health.
Mycological Assessment of Some Selected Fruits and Vegetables and Their Resistance Profile Against Some Antifungal Agents
(2025) Olanbiwoninu, Afolake Atinuke; Awotundun, Theresa Abimbola; Olayiwola, John Olusola; Fashogbon, Racheal Oluwayemisi
Fruits and vegetables offer distinct nutritional benefits and health-enhancing properties, driving their growing popularity. This research aimed to evaluate the mycological characteristics and investigate the antifungal resistance patterns of pathogens from selected fruits and vegetables. Samples, including watermelon, tomato, cucumber, and garden egg, were obtained from fruit markets and home gardens. They were subjected to microbiological analysis using standard procedures. The isolates were examined to determine their ability to cause disease, contribute to spoilage, and produce aflatoxins. Isolated pathogens were further subjected to antifungal sensitivity testing using the agar well diffusion method with three (3) antifungal agents. A total of eighteen (18) fungi were isolated from the genera Aspergillus (33.3 %), Candida (11.1 %), Cladosporium (5.6 %), Fusarium (5.6 %), Geotrichum (11.1 %), Penicillium (5.6 %), Pichia (16.6 %) and Saccharomyces (11.1 %). Isolates with haemolytic potential were 7, while 11 had spoilage potential, and 12 were pathogenic. Of the 12 pathogenic fungi, 9 (75%) were resistant to at least one antifungal agent while 3 (25%) showed no resistivity; however, among the Aspergillus spp., 5 (83%) were aflatoxigenic. The overall mycological quality of the analysed samples is low, improved hygienic practices should be encouraged among farmers, fruit and vegetable handlers and consumers.
Polyphasic characterisation of Bacillus subtilis strains for iru fermentation and vitamin bioenrichment
(2026) Awotundun, Theresa Abimbola; Greppi, Anna; Pugin, Benoit; Plüss, Serafina; Odunfa, Sunday Ayodele; Russo, Pasquale; Bokulich, Nicholas A; Olanbiwoninu, Afolake Atinuke
Bacillus subtilis plays a key role in traditional plant fermentations in Africa and Asia. Here, we characterised B. subtilis strains isolated from iru, a fermented condiment from Nigeria, and evaluated their potential as riboflavin- and folate-producers. Eighty-six Bacillus spp. were isolated through heat treatment and spore plating on nutrient agar. The isolates were phenotypically identified, assessed for enzymatic activity (proteases, amylases), and tested for safety (haemolysis, gelatinase, and biogenic amine production). Selected isolates were further screened for riboflavin and folate production in chemically defined media. Thirty-four strains were phenotypically identified as B. subtilis with riboflavin production ranging from 0.006 to 0.039 mg L−1, while nine produced folate between 0.300 and 1.940 mg L−1. These strains were submitted to the selective pressure of toxic analogues of riboflavin and folate in order to enhance their capability to synthesise these vitamins, with the best strain showing increases from 0.013 to 0.020 mg L−1 for riboflavin and 1.665 to 3.715 mg L−1 for folate. The most promising candidates were employed for lab-scale iru fermentation. In lab-scale iru fermentation using the improved strains, vitamin levels were enhanced by 38% for riboflavin (0.036 to 0.050 mg g−1 of iru) and 35% for folate (0.035 to 0.047 mg g−1 of iru), signifying that 10 g of iru fermented with these strains can provide 25% of daily riboflavin intake and 100% of folate intake. These results highlight the potential of selected B. subtilis strains as functional starter cultures for the dual purpose of iru fermentation and vitamin biofortification. Such strain selection and optimisation represent a promising biotechnological strategy to enhance the micronutrient profile of traditional fermented foods while preserving their sensory and cultural value.
Pre- and post-storage evaluation of nutritional profiles and aflatoxin contamination in maize, millet, and wheat in Oyo town
(Food Safety and Risk, 2026) Araoye, Martina Ivie; Awotundun, Theresa Abimbola; Oladipo, Iyabo Christianah; Olanbiwoninu, Afolake Atinuke
Cereal grains such as maize (Zea mays), millet (Pennisetum glaucum), and wheat (Triticum aestivum) are essential dietary staples in Nigeria, yet their nutritional quality and safety are often compromised by traditional storage practices. This study examined the impact of traditional storage on the nutritional quality and aflatoxin contamination of maize, millet, and wheat in Nigeria. Thirty grain samples (10 each) were collected, with one portion of each sample analysed immediately and the other stored for 7–8 months under traditional conditions. Proximate composition (protein, fat, ash, fibre, carbohydrate) and total aflatoxin levels were quantified using HPLC. Nutritional composition varied significantly (p < 0.05) between pre- and post-stored samples across all grains. Carbohydrate and protein contents generally declined after storage, while crude fibre and moisture showed variable trends. In maize, total aflatoxin content rose from 54.61 to 93.54 µg/kg pre-storage to 82.79–101.50 µg/kg post-storage. Millet ranged from 65.13 to 76.79 µg/kg to 81.89–99.24 µg/kg, while wheat increased from 56.22 to 58.20 µg/kg to 84.74–108.30 µg/kg. Aflatoxin B1 was the predominant toxin in all samples. These findings highlight the deterioration of nutritional quality and increased food safety risks in stored cereals, emphasising the need for improved storage systems, regular monitoring, and strict regulatory measures to safeguard consumer health.
Viruses That Heal: Harnessing Bacteriophages in the Era of Antibiotic Resistance
(Problems of Virology, 2026) Awotundun, Theresa Abimbola; Samson, Oyindamola John; Olanbiwoninu, Afolake Atinuke
The global rise in antimicrobial resistance (AMR) poses an urgent threat to public health, and novel alternatives to traditional antibiotics are needed. One of the most promising options is bacteriophages, viruses that infect and destroy bacteria. Once overshadowed by the discovery of antibiotics, phage therapy is now regaining attention, driven by advances in genomics, synthetic biology, and targeted medicine. This review examines the biology, diversity, and therapeutic use of bacteriophages in treating bacterial infections, especially those caused by multidrug-resistant pathogens. It also discusses how phages act through natural mechanisms, such as lytic enzymes (holins, endolysins, and muralysins), and highlights new genetic engineering techniques, such as CRISPR-Cas systems, phage recombineering, and synthetic genome reboots. In addition to clinical applications, we evaluate phages as biocontrol agents for food safety, environmental sanitation, and biofilm management. Additionally, the article explores key issues in phage therapy, including regulatory frameworks, formulation stability, dynamics of phage-host resistance, and the importance of rapid diagnosis. When properly integrated into modern health and biotechnology practices, bacteriophages offer significant potential and a sustainable solution to the global challenge of antimicrobial resistance.
Characterization, antioxidant and immunomodulatory potential on exopolysaccharide produced by wild type and mutant Weissella confusa strains
(Elsevier, 2018-05-30) Adebayo-Tayo, Bukola; Ishola, Racheal; Titiloye, Oyewunmi
Characterization, antioxidant and immunomodulatory potential of exopolysaccharide (EPS) produced by wild type and mutant Weissella confusa was investigated. The EPS production ranged from 5490.2 to 5580.7mg/L. Wild type Weissella confusa (WWCEPS) had the highest EPS production. Eight (8)sugar moieties were present in the EPS. Galactose had the highest EPS composition (34.6mg/100g and 33.5 mg/100g EPS) in Wild type Weissella confusa EPS (WWCEPS) and mutant Weissella confusa EPS (MWCEPS). Wild type Weissella confusa and mutant Weissella confusa EPS had antioxidant capacity. The scavenging assay for the antioxidant increased in a dose dependent (0.5–10 mg/mL) manner. Wild type Weissella confusa EPS had the highest 1,1-Diphemy 1-2-picryl-hydrazyl (DPPH) capacity, total antioxidant activity, hydrogen peroxide and reducing power activity (71%, 1.9%, 86.7% and 1.9%). The mice injected peritorially with mutant Weissella confusa EPS had the highest IgG and IgM (68–87mg/dL and 64–70 mg/dL). IgA of the mice treated with Wild type Weissella confusa EPS increased from 67 to 73 mg/dL Wild type and mutant Weissella confusa EPS had immunomodulatory activity on the treated mice.
Mutagenesis and Immobilization Effect on Exopolysaccharide Production by Weissella confusa and Lactobacillus delbrueckii
(Journal of Advances in Microbiology, 2018-04-27) Ishola, Racheal; Adebayo-Tayo, Bukola
Aims: This work aimed at investigating the effect of mutation and immobilization on EPS production and to characterize the EPS produced by L. delbrueckii and Weissella confusa. Study Design: To determine the effect of mutation using UV irradiation and immobilization using different matrixes on EPS production by the strains and to characterize the EPS produced. Methodology: Weissella confusa and Lactobacillus delbrueckii was exposed to UV irradiation and the wild and mutants strains was immobilized. The immobilized wild and mutants was used for EPS production. The produced EPS was characterized. Results: The LAB count that survived the UV irradiation reduced as the exposure time increases. The Wild L. delbrueckii produced more EPS (583.72 mg/L) than its mutant strain (581.42 mg/L). However, wild Weissella confusa and wild Lactobacillus delbrueckii produced more EPS than the mutant strain. Production of EPS by wild and mutant Weissella confusa immobilized in Sodium alginate (WWCNA and WWCNA), agar matrix (WWCAA and MWCAA) and polyurethane foam (WWCPF and MWCPF) ranged from 240.25 – 544.28 mg/L with WWCPF producing the highest (IWLDNA and IMLDNA), agar matrix (IWWCAA and IMLDAA) and polyurethane foam (WLDPF and MLDPF) ranged from 220.06 – 502.81 mg/L with IWLDPF producing the highest EPS. However, immobilization in agar matrix supported the least EPS production. Characterization of the EPS using FT-IR spectroscopy confirmed the presence of the different degrees of functional groups which indicates that they are polysaccharides, thus confirming the EPS. Un-immobilized Weissella confusa had the highest EPS production (558.72 mg/L and 583.61 mg/L) compared to the immobilized strains. Conclusion: Immobilization of mutant L. delbrueckii and Weissella confusa using polyurethane foam supported EPS production. EPS. Production of EPS by wild and mutant L. delbrueckii immobilized in Sodium alginate
Dr
(AU J.T., 2012-04-01) Fashogbon, Racheal; Adebayo-Tayo, Bukola
Production of bio-molecules is an important factor in assuring the proper consistency and texture of fermented foods. Lactic acid bacteria (LAB) isolated from fermented food were screened for lactic acid, diacetyl, hydrogen peroxide, pH development and Exopolysaccharide (EPS) production. Thirty-five strains of LAB were isolated and characterized from fermented dairy and non-dairy foods. The LAB species identified include: Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus cellobiosus, Lactobacillus delbruekii, Lactobacillus coryniformis, Lactobacillus casei, and Leuconostoc messenteroides. The most predominant species was Lactobacillus plantarum (34.29%). All the isolates were screened for lactic acid, hydrogen peroxide, diacetyl and pH and EPS production. Lactic acid production ranges within 0.11-1.96 mg/l in which the highest was produced by L. plantarum LPF2. L. plantarum LPF2 also produced the largest amount of diacetyl (1.92 mg/l). Hydrogen peroxide produce by the isolates ranges within 0.0002-.35 mg/l and L. fermentum LFBO1 produced the highest. The pH ranged within 3.2-6.5 in which L. plantarum LPF2 had the least. L. plantarum LPW7 and LPBO9, Leu. messenteroides LMWO2 and LMW4 bring the reduction of the pH of the fermentation medium to 3.8 at 36 hours. All the isolates were screened for EPS production on solid medium. The isolates were all creamy; four were highly mucoid, eight were mucoid while twenty-three were slightly mucoid. All the isolates are EPS producers, EPS production ranged within 120-1,390 mg/l in which the highest was produced by L. fermentum LF6.
Synergistic use of nanoparticles and probiotic lactic acid bacteria in combating pathogens: mechanisms, applications and safety considerations
(Nano Plus: Sci. Technol. Nanomater., 2026-04-20) Oladipo, Christianah; Sangodare, A; Ogunsona, S; Fashogbon, Racheal; Ohijeagbon, O
The increasing threat of antimicrobial resistance (AMR) necessitates interest in the development of novel, highly potent, and biologically compatible methods for pathogen control. The combination of Probiotic Lactic acid bacteria and nanoparticles creates two different approaches that work together to achieve strong antimicrobial effects. Lactic acid bacteria (LAB) function as natural antagonists that produce strong antimicrobial substances, that include organic acids and bacteriocins and hydrogen peroxide, to create an environment that prevents other pathogens from growing. The nanoparticles (NPs), which include silver and iron oxide and zinc oxide, liposomes, selenium exhibit strong antibacterial properties because they induce cell death through their membrane destruction capabilities and ion discharge mechanisms and reactive oxygen species (ROS) generation. The integration of probiotic LAB with nanoparticles offers enhanced antimicrobial at lower dosages. However, challenges related to nanotoxicology, stability of probiotic nanoparticle systems, and clinical safety remain critical considerations. This synergy approach represents a promising strategy for tackling AMR with potential applications in food safety and healthcare.
Green synthesis of selenium nanoparticles from Helianthus annuus leaf extracts: antioxidant and antimicrobial activities on foodborne pathogens
(Nano Plus: Sci. Technol. Nanomater, 2025-07-18) Fashogbon, Racheal; Akinade, K; Emozozo, O; Samson, Oyindamola; Adegbuyi, G; Oladipo, I
The increasing global demand for safer food and antibiotic resistant products has incited momentous interest in eco-friendly strategies for the control of foodborne pathogenic microbes. The conventional synthesis of selenium nanoparticles using chemicals is hazardous, energy-intensive, thereby raises environmental concerns. The green synthesis of Selenium nanoparticles (SeNPs) using Helianthus annuus provides a sustainable and effective platform for combating foodborne pathogens, owing to their low toxicity profile and multifaceted antimicrobial mechanisms. Helianthus annuus. This study, therefore, emphasized the green synthesis of selenium nanoparticles (SeNPs) from Helianthus annuus leaf extract using ethyl acetate (SeNPEa) and methanolic (SeNPM) extraction techniques, along with the antioxidant and antimicrobial activity of the resulting nanoparticles against foodborne pathogens. UV-Visible (UV-Vis), Fourier transform infrared (FT-IR), Energy Dispersive X-ray (EDX), Scanning Electron Microscopy (SEM), and X-ray Diffraction Techniques (XRD) were used to characterize the SeNPs. The antioxidant and antibacterial potential of the synthesized SeNPs were evaluated. The two extracts showed no cardiac glucosides, and the existence of flavonoids, tannins, saponins, and steroids was observed. The extract changed the colour of the Se salt solution, with SeNPEaHa and SeNPMHa showing a maximum UV-Vis absorbance at 269 nm and 275 nm, respectively. The SEM analysis shows that the size of the SeNPEaHa and SeNPMHa at 10 and 20 µm. The quantitative analysis using EDX showed a high selenium content of 74.60% in SeNPEaHa and 72.12% in SeNPMHa. The functional groups, such as hydroxyl, alcohol, phosphate, and amine, were accountable for the capping and stabilization of nanoparticle proteins. The DPPH radical scavenging activity and reducing power scavenging assay contents of SeNPEaHa and SeNPMHa increased in a dose-dependent manner and were higher than those of ascorbic acid, used as a control. The SeNPEaHa and SeNPMHa were susceptible to Escherichia coli 700728, Staphylococcus aureus 6571, and Staphylococcus epidermidis. This result confirmed that Helianthus annuus is a potential biomaterial for synthesizing SeNPs, which can be exploited for its antioxidant and antibacterial activities.
ENHANCEMENT OF SOURDOUGH BREAD USING PROBIOTIC LACTIC ACID BACTERIA ISOLATED FROM CORN STEEP LIQUOR
(Journal of Faculty of Food Engineering, Ştefan cel Mare University of Suceava, Romania, 2025-02-27) Fashogbon, Racheal; Popoola, Bukola; Samson, Oyindamola; Akinwunmi, Ismail; Ojo-Omoniyi, Olusola
Fermented Zea mays (OGI), an edible paste made from fermented grains specific to the region, is an integral part of the human diet. Corn steeping liquor (CSL) is an important by-product obtained from the wet milling of Zea mays. The present study was conducted to investigate the probiotic characteristics and in vitro antibacterial activity of lactic acid bacteria (LAB) obtained from CSL, as well as their impact on the quality of sourdough bread. A total of 46 LAB were isolated and evaluated for their probiotic potential. The probiotic potential of LAB was determined by evaluating their hemolytic capacity, bile salt resistance, phenol tolerance, antimicrobial and antioxidant activities. The lactic acid bacteria with the most promising probiotic potential were molecularly characterized and used for the production of sourdough bread (SDB). Conventional microbiological methods identified Lactobacillus plantarum (21%), Lactobacillus fermenti, and Leuconostoc mesenteroides (17%) as the predominant LAB species. Twelve LAB showed signs of gamma hemolysis. It is noteworthy that isolate CSL23 showed the highest bile tolerance, while isolates CSL15, CSL23, and CSL6 demonstrated the highest phenol tolerance. Isolates CSL15, CSL23, and CSL29 showed significant inhibition zones of 15.00 ± 0.18 mm, 20.5 ± 0.26 mm, and 22.60 ± 0.31 mm against four tested pathogens, in addition to effective antioxidant scavenging activity. Molecular identification revealed that LAB isolates CSL15, CSL23, and CSL29 were Lactiplantibacillus plantarum ROF4, Lactiplantibacillus plantarum ROF5, and Lactiplantibacillus plantarum ROF6, respectively. This finding indicates that all LAB strains belong to the same genus. Therefore, it is evident that the current study demonstrated that Lactiplantibacillus plantarum strains isolated from CSL have the potential to serve as promising probiotic starter cultures that could be used in the production of sourdough bread with improved functional properties.
Phytochemical and Antimicrobial Potentials of Aqueous Leaves Extracts of Helianthus annuus (Sunflower): A Natural Preservative in Food Industry
(Greener Journal of Agricultural Sciences, 2025-07-18) Fashogbon, Racheal; Aforijiku, Samuel; Adegbuyi, Gbemisola; Akinola, T
Helianthus annuus (sunflower) is an important plant that belongs to the family Asteraceae and usually used as oil in the food industry. This study investigates the phytochemical and antimicrobial potentials of aqueous leaf extracts from Helianthus annuus (AqHa). The H.annuus leaves were collected from botanical section of Ajayi Crowther University, Oyo and were taken to the laboratory and processed into aqueous extract using standard method. The Aqueous leaf extracts from Helianthus annuus (AqHa) were assessed for phytochemical attributes, Fourier transform infrared Spectroscopy (FTIR), antioxidant activity and antimicrobial potential against food pathogens using standard procedures. Phytochemical analysis of the assessed extracts revealed the presence of some plant metabolites including flavonoids, steroid, tannins and saponins while FTIR showed the presence of some key functional groups such as O-H stretch, H-bonded, O-H stretch, H-bonded, Methylene C-H stretch, Methyne C-H stretch and C=C Conjugated bonds. The peak at 2355.00 cm1 and 1735.60 cm1 were related to stretch vibration of Methylene C-H and C=C, respectively both denoting the presence of fat while the highest peak (3759.57 cm-1) was related to hydroxyl group. AqHa had the highest zone of inhibition (13 mm) against Staphylococcus aureus while the least (7 mm) inhibition was on Staphylococcus spp. The highest antioxidant activity was evaluated as Hydrogen peroxide scavenging assay (56 and 87%) and reducing power scavenging assay (49% and 83%). Aqueous leaf extracts from Helianthus annuus (AqHa) contains phytochemical compounds, had antioxidant activity and antimicrobial potentials on food pathogens, and could be used as an alternative in the development of plant based antimicrobials or as preservatives in food industries.
Screening and Molecular Identification of Biosurfactant-Producing Bacteria Isolated from Contaminated Soil and Vegetables in Ago-Iwoye, Nigeria
(ASRIC Journal on Natural Sciences, 2024) Samson, Oyindamola; Fashogbon, Racheal; Okonkwo, Chikezie; Adeyemi, Jamiu; Adekola, Hafees; Makanjuola, Stephen; Salisu, Titilola; Aina, Sulaiman; Kazeem, Muinal; Onajobi, Ismail
Biosurfactants play a crucial role in bioremediation processes, wherein bacteria producing these surfactants utilize contaminants or pollutants as energy and nutrient sources. This study aims to screen and molecularly identify bacteria recovered from soil contaminated by cassava effluent and various vegetables for biosurfactant production. Standard methods were used for bacterial counting, isolation, and identification. Blood hemolysis and oil spreading tests evaluated biosurfactant production. High producers were characterized by 16S rRNA sequencing. Mean values compared and significance tested using chi-square. The mean bacterial counts were 67.00±2.54 for Ago-Iwoye soil, 86.00±4.35 or Oru soil, 102.00±3.32 for Ago-Iwoye vegetables, and 109.00±4.83 for Oru vegetables. Isolates AS1, AS2, CSA34, CSA36, CSO48, CSO49 showed partial hemolysis (10.00 – 14.00 mm), while others exhibited complete hemolysis (Isolates FP11, LS15, CSO45). Isolate LS30 showed no hemolytic activity. Among the isolates tested, only LS15 and CSO45 exhibited positive oil spreading ability, with diameters of 5.00 ± 2.50 mm and 7.50 ± 3.54 mm, respectively. Staphylococcus aureus and Bacillus spp. proved to be the highest biosurfactant producer by showing better results. The molecular characterization of the identified isolate LS15 revealed a 100% match with Staphylococcus aureus 8 BWI (accession number KX456108.1), while isolate CSA45 was identified as Bacillus marasmi with 96.6% similarity (accession number NR_147397.1). Therefore, sustained attention to Staphylococcus spp. and Bacillus spp. is warranted, given their consistent success in screening tests as proficient biosurfactant producers.
Exploring Antimicrobial and Antioxidant Capacities of Molecularly Characterized Lactic Acid Bacteria strains from Fermented Zea mays (Ogi)
(ASRIC Journal on Natural Sciences, 2024-10-10) Fashogbon, Racheal; Awotundun, Theresa; Samson, Oyindamola; Nseobong, Micheal; Nudewenu, Sarah; Adebayo-Tayo, Bukola
Lactic Acid Bacteria (LAB) present during ogi fermentation exhibit notable functional traits, including antimicrobial and antioxidant capabilities. This study aims to assess the antimicrobial and antioxidant potentials of LAB strains isolated from Ogi samples. The LAB was isolated from fermented Ogi sourced from local markets using deMan, Rogosa, and Sharpe (MRS) agar. The isolates underwent biochemical and molecular characterization. Antimicrobial and antioxidant potentials, including 1,1-Diphenyl-2picryl-hydrazyl (DPPH) radical scavenging assay, reducing power scavenging assay, and total antioxidant activity, were investigated. Eighteen LAB strains were isolated, with Lactobacillus delbrueckii (33%), Lactobacillus plantarum (39%), Lactobacillus casei (11%), Streptococcus thermophiles (11%), and Lactobacillus fermentii (6%) being the most frequent. Notably, LABOG10, LABOG7, and LABOG14 exhibited significant inhibition against Staphylococcus aureus, E. coli, and Candida sp., respectively. The culture filtrates of these strains demonstrated potent scavenging activity. Through molecular characterization, it was determined that the three distinct isolates, namely Lactiplantibacillus plantarum (LABOG7 and LABOG14) and Streptococcus sanguinis (LABOG10), were all identified as Lactiplantibacillus plantarum. Specifically, LABOG7 and LABOG14 were designated as strains ROF1 and ROF2, respectively. The accession number OM491514.1 corresponds to the 16S rRNA sequence of Lactiplantibacillus plantarum strain ROF1, while OM491515.1 corresponds to the sequence of Lactiplantibacillus plantarum strain ROF2. LABOG10 was identified as Streptococcus sanguinis, designated as strain ROF3. Streptococcus sanquinis ROF3, Lactiplantibacillus plantarum strain ROF1, and Lactiplantibacillus plantarum strain ROF2 demonstrate significant inhibitory activity against selected pathogens. Moreover, their potent antioxidant properties suggest potential in preventing diseases associated with oxidative stress.
MOLECULAR AND BIOCHEMICAL CHARACTERIZATION OF AUTOCHTHONOUS CELLULOLYTIC MICROORGANISMS FROM THREE LANDFILL SITES IN LAGOS, SOUTHWEST NIGERIA
(Journal of Faculty of Food Engineering, Ştefan cel Mare University of Suceava, Romania, 2024-04-03) Ojo-Omoniyi, Olusola; Buraimoh, Maria; Jolaoluwa, Grace; Akindusoye, Opeyemi; Fashogbon, Racheal
This study was conducted to evaluate and identify native cellulolytic microorganisms to tropical sanitary landfill sites in Lagos, Southwest Nigeria as well as to provide insights into the potential of autochthonous microorganisms in solid waste management. Soil and leachate samples were obtained simultaneously (0 – 30 cm depth) at the same time from three waste dumpsites in Lagos, using aseptic procedures. Thereafter, composite soil samples and leachates were generated independently and transported to the laboratory for analysis. Microorganisms were isolated from both soil and leachate samples using the serial dilution technique on sterile nutrient agar (NA) and potato dextrose agar (PDA). Subsequently, cellulase-producing microbial species were identified using conventional and standard microbiological techniques as well as by cultivation on Starch-casein-agar. Pure cultures of isolates were inoculated on sterile filter paper placed on Starch - casein agar plate. Isolates were selected based on their metabolic capabilities to utilize the filter paper for growth. Screening for utilization of aromatic acids was carried out in 250 mL conical flasks containing composition: minimal agar medium (pH 7.2), 1.0 g/L aromatic acids (vanillic), 1.0 mL trace elements, phosphate buffer and Bromothymol blue as pH indicator. The DNA of some selected isolates with cellulolytic activity were extracted and sequenced using 16S rRNA sequencing, ITS, and bioinformatics tools. Consequently, among the bacterial species, Bacillus sp. had the highest cellulose degradative ability and was the most prevalent (50%) in occurrence among bacterial species while Aspergillus sp. emerged as the most commonly occurring fungal isolate (35.7%). Data of selected sequenced cellulolytic isolates were deposited at NCBI GeneBank with Accession numbers: KP843680.1 (Vibrio tubiashii), MK748310.1(Aspergillus aculeatinus), LC496490.1 (Aspergillus aculeatus), CP029751.1 (Staphylococcus aureus) and JX144699.1 (Bacillus mycoides). Environmental surveillance of these microorganisms with microbial synergistic capabilities, could transform solid waste management into a highly efficient biotechnological process that facilitates volume reduction, waste recycling and Bioenergy production.
Microbial gamma-aminobutyric acid synthesis: a promising approac h f or functional f ood and pharmaceutical applications
(Letters in Applied Microbiology, 2024-11-12) Fashogbon, Racheal; Samson, Oyindamola; Awotundun, Theresa; Olanbiwoninu, Afolake; Adebayo-Tayo, Bukola
Gamma-aminobutyric acid (GABA) is a non-protein amino acid that is a main inhibitory neurotransmitter in the mammalian central nervous system. This mini-review emphasis on the microbial production of GABA and its potential benefits in various applications. Numerous microorganisms, including lactic acid bacteria, have been identified as efficient GABA producers. These microbes utilize glutamate decarboxylase enzymes to convert L-glutamate to GABA. Notable GABA-producing strains include Lactobacillus brevis , Lactobacillus plant arum , and certain Bifidobacterium species. Microbial GABA production offers numerous benefits over chemical synthesis, including cost-effectiveness, sustainability, and the potential for in situ production in fermented foods. Recent research has optimized fermentation conditions, genetic engineering approaches, and substrate utilization to enhance GABA yields. T he benefits of GABA extend beyond its neurotransmitter role. Studies have shown its potential to reduce blood pressure, assuage anxiety, impro v e sleep quality, and improve cognitive function. These properties make microbial GABA production particularly attractive for developing functional foods, nutraceuticals, and pharmaceuticals. Future research directions include exploring novel GABA-producing strains, improving production efficiency, and investigating additional health benefits of microbially produced GABA.
Genotyping of ESBL-Producing E. coli from Food-producing Animals, Animal Food Products and Humans in South-West, Nigeria
(Ajayi Crowther Journal of Pure and Applied Sciences, 2022-10-10) Adefioye, Olusolabomi; Olaleye Eniola; Feruke-Bello, Yetunde; Fashogbon, Racheal; Akindele Ibukun; Olulowo Ojedele
Extended-spectrum beta-lactamase- (ESBL-) producing Escherichia coli strains are emerging globally in both humans and animals. The use of antibiotics in animal production and treatment has led to this phenomenon. This study aimed at determining the resistance patterns of E. coli isolates from humans, food-producing animals, and their food products in South-western Nigeria. The prevalence and distribution of antibiotic-resistant E. coli in three categories were evaluated: Animals (goats, pigs, poultry, cattle, sheep), Humans (butchers, meat sellers, animal farm workers, buyers), and Animal food products (milk, cheese, beef, chicken, yogurt) from selected animal farms in South-west Nigeria. Out of a total number of 280 samples that were collected, 216 E. coli strains were isolated. The prevalence of isolated E. coli from humans (96%) was higher than that from animals (89%) and about 38.8% were isolated from animal food products. Out of the 216 E. coli isolates that were obtained from the different sources, 60 (27.8%) were multiple drug-resistant and were also ESBL- positive. Seven resistance genes were amplified in the multi-drug resistant Escherichia coli isolates: TEM (61.7%), CTX-M-15 (51.7%), AAC-6-LB (43.3%), CTX-M-1 (38.3%), CTX-M-9 (33.3%), CTX-M-2 (21.7%) and SHV (11.7%). The results suggest the need for continuous surveillance of antibiotic resistance to curtail the spread of resistance bacteria.
Bacteriological Quality and the Antibiogram of Isolates from Raw Cow Milk Produced in Ibadan Metropolis Oyo State, Nigeria
(Nigerian Journal of Microbiology, 2023-06-12) Adediran, A; Aforijiku, Samuel; Adediran, A; Fashogbon, Racheal
This study aimed at evaluating the bacteriological quality as well as the antibiogram (antibiotic sensitivity profile) of organisms isolated from raw cow milk produced in Ibadan metropolis. Raw cow milk samples were collected from University of Ibadan Research farm, Bodija, Sabo and Akinyele cow settlement ibadan. Bacterial counts, isolation and phenotypic identification of bacterial isolated from the assessed raw cow milk were determined using standard procedures. Antibiotic sensitivity tests was carried out by disc diffusion method. The total bacterial counts and total coliform counts ranged between 0.9×106 to 4.5×106 CFU/ml and 0.4×106 to 4.2×106 CFU/ml, respectively. Fourty-two (42) bacterial isolates were identiifield as Staphylococcus aureus (16), Escherichia coli (8), Salmonella typhimurium (6), Shigella dysentriae (6), Enterobacter aerogenes (4) and Serretia marcescens (2). Based on the antibiogram, S. aureus, E. coli , S. typhi and S. dysentriae had 100% resistance to Tetracycline, Gentamycin and Nitrofurantoin while Serratia marcescens strains had 100% susceptibility to all the antibiotic except Nitrofurantoin which had 50% susceptibility and Tetracycline which had 100% resistance. All of the E.coli isolates were resistance to tetracycline. The raw cow milk samples analysed exceeded the WHO microbiological standard of 1.0×105 CFU/mL and 3.0×101 CFU/mL for total bacteria count and coliform count for raw milk respectively. The antibiogram studies revealed that some bacteria isolates were resistant to most of the antibiotics used. This may pose a high risk of milk borne illnesses among consumers and put them at risk of being infected with antibiotic resistant strains of pathogenic bacteria. There is utmost need for an awareness program with a follow up mechanism to educate dairy farmers and handlers on hygienic production practices and discourage the indiscriminate use of antibotics to have a wholesome milk.

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