Shruthi B, Adithi G, Deepa N, Divyashree S, Sreenivasa M Y
Applied Mycology Lab, Department of Studies in Microbiology, University of Mysore, Mysuru, 570006, Karnataka, India.
Probiotics Antimicrob Proteins. 2024 Aug 24. doi: 10.1007/s12602-024-10342-z.
Though numerous bacteria have been used as probiotics by industries, at present, Saccharomyces boulardii and Saccharomyces cerevesiae are the only yeast probiotics which are industrially exploited. In view of this, yeast probiotics were isolated from traditional fermented foods and products collected from different parts of Karnataka, India. In this work, we have studied the probiotic attributes of ten yeast isolates isolated from different traditionally fermented foods and products. About 73 yeast isolates were initially isolated by serially diluting the samples and plating on the Potato Dextrose Agar (PDA) plates. The spot assay was performed to screen the yeast isolates against test pathogens. Ten isolates were selected based on their significant antimicrobial activity. These isolates were subjected to biochemical characterization and then assessed for probiotic properties. The ability of probiotics to endure at pH 2.0 and tolerate bile conditions (0.3%) are crucial attributes for the survival in the gastrointestinal tract (GIT). The yeast isolates were also assessed for cell surface hydrophobicity and autoaggregation capabilities. All the ten isolates showed endurance in GIT tract and > 40% of adhesion. The study further examined cholesterol assimilation, antioxidant and antagonistic properties of the yeasts. Subsequently, the molecular characterization was performed by isolating the DNA of yeast isolates by phenol-chloroform method and identified molecularly through sequencing of D1/D2 regions. The isolates tested negative for gelatinase and DNase and were non-haemolytic indicating they are safe for consumption. Among ten isolates, Meyerozyma guillermondii (MYSY23), Meyerozyma caribbica (MYSY22) and Meyerozyma guillermondii (MYSY19) showed significant results for all probiotic and functional characteristics with greater than 65% survivability in GIT tract and > 50% of antagonistic activity against test pathogens and also proved non-cytotoxic and safe. These findings suggest that yeasts with significant probiotic attributes could be recommended for various probiotic application.
尽管众多细菌已被工业用作益生菌，但目前，布拉氏酵母菌和酿酒酵母是仅有的两种被工业开发利用的酵母益生菌。鉴于此，从印度卡纳塔克邦不同地区收集的传统发酵食品和产品中分离出了酵母益生菌。在这项工作中，我们研究了从不同传统发酵食品和产品中分离出的10株酵母菌株的益生菌特性。最初通过对样品进行系列稀释并接种在马铃薯葡萄糖琼脂（PDA）平板上，分离出约73株酵母菌株。进行斑点试验以筛选酵母菌株对测试病原体的抗菌活性。基于其显著的抗菌活性选择了10株菌株。对这些菌株进行生化特性鉴定，然后评估其益生菌特性。益生菌在pH 2.0环境下的耐受性以及对胆汁条件（0.3%）的耐受能力是其在胃肠道（GIT）中存活的关键特性。还评估了酵母菌株的细胞表面疏水性和自聚集能力。所有10株菌株在胃肠道中均表现出耐受性且粘附率>40%。该研究进一步检测了酵母的胆固醇同化、抗氧化和拮抗特性。随后，通过酚-氯仿法分离酵母菌株的DNA进行分子特性鉴定，并通过D1/D2区域测序进行分子识别。这些菌株的明胶酶和DNA酶检测呈阴性且不溶血，表明它们食用安全。在10株菌株中，季也蒙毕赤酵母（MYSY23）、加勒比毕赤酵母（MYSY22）和季也蒙毕赤酵母（MYSY19）在所有益生菌和功能特性方面均表现出显著结果，在胃肠道中的存活率大于65%，对测试病原体的拮抗活性>50%，并且还证明无细胞毒性且安全。这些发现表明，具有显著益生菌特性的酵母可推荐用于各种益生菌应用。
