Awotundun Theresa, Olanbiwoninu Afolake
Department of Microbiology and Biotechnology, Ajayi Crowther University, P. O. Box 1066, Oyo State, Nigeria.
Access Microbiol. 2025 Jan 28;7(1). doi: 10.1099/acmi.0.000883.v3. eCollection 2025.
Riboflavin (vitamin B) is a water-soluble compound that plays an important role in multiple cellular functions. This study evaluates the probiotic potential of riboflavin-overproducing strains isolated from fermented African locust beans. After strain improvement, ACU-I11MR and ACU-I163MR were selected due to their higher riboflavin production (0.01905±0.0005 mg l to 0.0259±0.0077 mg l and 0.0195±0.0054 mg l to 0.0267±0.0013 mg l, 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 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. ACU-I163MR, showing superior probiotic potential, could be a promising candidate for developing riboflavin-enriched -fermented functional foods.
核黄素（维生素B）是一种水溶性化合物，在多种细胞功能中发挥着重要作用。本研究评估了从发酵非洲刺槐豆中分离出的高产核黄素菌株的益生菌潜力。经过菌株改良后，选择了ACU-I11MR和ACU-I163MR，因为它们的核黄素产量更高（分别为0.01905±0.0005毫克/升至0.0259±0.0077毫克/升和0.0195±0.0054毫克/升至0.0267±0.0013毫克/升）。通过溶血试验、抗生素敏感性测试以及明胶酶和生物胺活性的缺失来确认它们的安全性。通过包括对低pH、胆盐、苯酚、温度和氯化钠的抗性；自聚集；细胞疏水性；生物膜形成；抗菌活性；以及酶和胞外多糖产生等试验来评估益生菌潜力。两株菌株均无溶血现象，明胶酶和生物胺活性均为阴性。它们在pH 2（存活率85.05%；87.09%）、1%胆盐（存活率88.82%；87.64%）和0.5%苯酚（存活率48.80%；59.52%）条件下分别表现出显著的活力。ACU-I11MR对12种抗生素中的9种敏感，而ACU-I163MR则100%敏感。这些菌株表现出较强的细胞表面黏附力和自聚集能力，并能抑制多种病原菌。它们能产生淀粉酶、蛋白酶和胞外多糖，并且在各种温度和氯化钠条件下都能生长。表现出卓越益生菌潜力的ACU-I163MR可能是开发富含核黄素的发酵功能性食品的有前途的候选菌株。
