Alkalbani Nadia S, Osaili Tareq M, Al-Nabulsi Anas A, Obaid Reyad S, Olaimat Amin N, Liu Shao-Quan, Ayyash Mutamed M
Department of Food Science, College of Agriculture and Veterinary Medicine, United Arab Emirates University (UAEU), Al Ain P.O. Box 15551, United Arab Emirates.
Department Clinical Nutrition and Dietetics, University of Sharjah, Sharjah P.O. Box 27272, United Arab Emirates.
J Fungi (Basel). 2022 May 23;8(5):544. doi: 10.3390/jof8050544.
This study is about the isolation of yeast from fermented dairy and non-dairy products as well as the characterization of their survival in in vitro digestion conditions and tolerance to bile salts. Promising strains were selected to further investigate their probiotic properties, including cell surface properties (autoaggregation, hydrophobicity and coaggregation), physiological properties (adhesion to the HT-29 cell line and cholesterol lowering), antimicrobial activities, bile salt hydrolysis, exopolysaccharide (EPS) producing capability, heat resistance and resistance to six antibiotics. The selected yeast isolates demonstrated remarkable survivability in an acidic environment. The reduction caused by in vitro digestion conditions ranged from 0.7 to 2.1 Log. Bile salt tolerance increased with the extension in the incubation period, which ranged from 69.2% to 91.1% after 24 h. The ability of the 12 selected isolates to remove cholesterol varied from 41.6% to 96.5%, and all yeast strains exhibited a capability to hydrolyse screened bile salts. All the selected isolates exhibited heat resistance, hydrophobicity, strong coaggregation, autoaggregation after 24 h, robust antimicrobial activity and EPS production. The ability to adhere to the HT-29 cell line was within an average of 6.3 Log CFU/mL after 2 h. Based on ITS/5.8S ribosomal DNA sequencing, 12 yeast isolates were identified as 1 strain for each and and 10 strains for .
本研究旨在从发酵乳制品和非乳制品中分离酵母，并对其在体外消化条件下的存活情况以及对胆盐的耐受性进行表征。筛选出有潜力的菌株，进一步研究其益生菌特性，包括细胞表面特性（自聚集、疏水性和共聚集）、生理特性（对HT-29细胞系的黏附及降胆固醇能力）、抗菌活性、胆盐水解、胞外多糖（EPS）产生能力、耐热性以及对六种抗生素的抗性。所选酵母菌株在酸性环境中表现出显著的生存能力。体外消化条件导致的菌数减少范围为0.7至2.1个对数级。胆盐耐受性随培养时间延长而增加，24小时后范围为69.2%至91.1%。12株所选菌株去除胆固醇的能力在41.6%至96.5%之间，且所有酵母菌株均表现出水解所筛选胆盐的能力。所有所选菌株均表现出耐热性、疏水性、较强的共聚集性、24小时后的自聚集性、强大的抗菌活性以及EPS产生能力。2小时后对HT-29细胞系的黏附能力平均为6.3 Log CFU/mL。基于ITS/5.8S核糖体DNA测序，12株酵母菌株被鉴定为1株为 ，1株为 ，10株为 。
