乳酸菌产生的胞外多糖因其潜在的健康益处和在功能性食品中的应用而受到关注。这项研究探索了从乳制品中分离和表征一种新型的胞外多糖产生菌株。目的是评估其益生菌潜力并研究所产生的胞外多糖的性质。从牛黄油中分离出的菌株被鉴定为屎肠球菌PCH.25,证明了胞外多糖的生产。该研究的新颖性在于对该菌株及其胞外多糖的全面表征,揭示独特的特性,在食品中具有潜在的应用,化妆品,和制药行业。屎肠球菌PCH.25菌株表现出较强的耐酸性,孵育2小时后,pH2的存活率为92.24%。它还表现出显著的自动聚集(24小时后85.27%)和共同聚集能力,抗生素敏感性,没有溶血活性,表明了它的益生菌潜力。该菌株产生的胞外多糖对单核细胞增生李斯特菌显示出杀菌活性(MIC和MBC=1.8mg/ml)和抗氧化特性(22.8%)。化学分析显示由葡萄糖和果糖单体组成的杂多糖,各种官能团有助于其生物活性。胞外多糖的物理表征表明,热稳定性高达270°C,负ζ电位(-27mV),平均粒径为235nm。扫描电子显微镜和能量色散X射线分析显示,主要由碳和氧组成的无孔结构,具有无定形的性质。这些发现表明,来自屎肠球菌PCH.25的胞外多糖具有作为天然抗菌和抗氧化聚合物用于功能性食品的潜力,化妆品,和药物。
Exopolysaccharides produced by lactic acid bacteria have gained attention for their potential health benefits and applications in functional foods. This study explores the isolation and characterization of a novel exopolysaccharide-producing strain from dairy products. The aim was to evaluate its probiotic potential and investigate the properties of the produced exopolysaccharide. A strain identified as Enterococcus faecium PCH.25, isolated from cow butter, demonstrated exopolysaccharide production. The study\'s novelty lies in the comprehensive characterization of this strain and its exopolysaccharide, revealing unique properties with potential applications in food, cosmetic, and pharmaceutical industries. The E. faecium PCH.25 strain exhibited strong acid tolerance, with a 92.24% viability rate at pH 2 after 2 h of incubation. It also demonstrated notable auto-aggregation (85.27% after 24 h) and co-aggregation abilities, antibiotic sensitivity, and absence of hemolytic activity, suggesting its probiotic potential. The exopolysaccharide produced by this strain showed bactericidal activity (MIC and MBC = 1.8 mg/ml) against Listeria monocytogenes and antioxidant properties (22.8%). Chemical analysis revealed a heteropolysaccharide composed of glucose and fructose monomers, with various functional groups contributing to its bioactivities. Physical characterization of the exopolysaccharide indicated thermal stability up to 270 °C, a negative zeta-potential (-27 mV), and an average particle size of 235 nm. Scanning electron microscopy and energy dispersive X-ray analysis revealed a smooth, nonporous structure primarily composed of carbon and oxygen, with an amorphous nature. These findings suggest that the exopolysaccharide from E. faecium PCH.25 has potential as a natural antibacterial and antioxidant polymer for use in functional foods, cosmetics, and pharmaceuticals.