Bitew Dagnew, Damtew Bogale, Tesfaye Anteneh, Andualem Berhanu
Department of Biology, College of Natural and Computational Science, Mizan-Tepi University, Ethiopia.
Department of Industrial Biotechnology, Institute of Biotechnology, University of Gondar, Ethiopia.
Heliyon. 2024 Nov 22;10(23):e40520. doi: 10.1016/j.heliyon.2024.e40520. eCollection 2024 Dec 15.
Traditional fermented foods and beverages are important sources of probiotic microbes. The purpose of this study was to isolate yeast from Ethiopian fermented beverages and assess their probiotic activity in an setting. Yeast isolation, identification, and probiotic trait screening were conducted in accordance with established protocols. Eleven isolates were obtained. Of them, GB1D5, RTj3D3 and DMTD2 were low hydrogen sulfide producers and were selected. The D1/2 genotyping of selected isolates revealed that they were strains of . All strains grew well at low pH, body temperature, bile salt concentrations (0.3-0.6 (w/v)) and survived at simulated gastrointestinal conditions with survival percentages of 12.8 ± 4.9 to 14.4 ± 5.0 % and 5.3 ± 1.7-5.9 ± 1.8 %, respectively. They demonstrated surface hydrophobicity ranging from 61.3 to 68.7 %; and 80.7-86 % auto-aggregation percentages after 24 h of incubation. They also showed hydroxyl radical scavenging activity ranging between 91.6 and 92.3 % and mild inhibitory activity against (ATCC 893614) and (ATCC 892760). The PCA revealed that two strains (DMTD2 and RTj3D3) have a strong association with most probiotic properties, which affirms their promising candidacy. Safety assessments indicated that they were resistant to antibacterial antibiotics, susceptible to antifungals, and negative for protease, gelatinase, biogenic amine production, and hemolytic activity. All these suggest that they are promising candidates for the production of food containing probiotics. Examining their performance in vivo circumstances is recommended.
传统发酵食品和饮料是益生菌微生物的重要来源。本研究的目的是从埃塞俄比亚发酵饮料中分离酵母，并在体外环境中评估其益生菌活性。酵母的分离、鉴定和益生菌特性筛选按照既定方案进行。共获得11株分离株。其中，GB1D5、RTj3D3和DMTD2产硫化氢量较低，被选中。对所选分离株的D1/2基因分型显示它们是某种菌株。所有菌株在低pH值、体温、胆汁盐浓度（0.3 - 0.6（w/v））下生长良好，并在模拟胃肠道条件下存活，存活百分比分别为12.8±4.9%至14.4±5.0%和5.3±1.7%至5.9±1.8%。它们表现出61.3%至68.7%的表面疏水性；孵育24小时后自动聚集百分比为80.7%至86%。它们还表现出91.6%至92.3%的羟自由基清除活性以及对某种菌（ATCC 893614）和另一种菌（ATCC 892760）的轻度抑制活性。主成分分析显示，两株菌（DMTD2和RTj3D3）与大多数益生菌特性有很强的关联，这证实了它们有成为优良候选菌株的潜力。安全性评估表明它们对抗菌抗生素有抗性，对抗真菌药物敏感，且蛋白酶、明胶酶、生物胺产生和溶血活性均为阴性。所有这些表明它们是生产含益生菌食品的有前途的候选菌株。建议在体内环境中检验它们的性能。
