AUTHOR=Youn Hye-Young , Kim Dong-Hyeon , Kim Hyeon-Jin , Bae Dongryeoul , Song Kwang-Young , Kim Hyunsook , Seo Kun-Ho 

TITLE=Survivability of Kluyveromyces marxianus Isolated From Korean Kefir in a Simulated Gastrointestinal Environment

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.842097

DOI=10.3389/fmicb.2022.842097

ISSN=1664-302X

ABSTRACT=<p><italic>Kluyveromyces marxianus</italic> accounts for &gt; 90% of the yeast population of kefir, and recently, its probiotic potential has been actively explored with a focus on its health benefits and safety. Herein, the survivability of five kefir-isolated <italic>K. marxianus</italic> strains (Km A1–A5) in a simulated gastrointestinal (GI) environment was evaluated and compared with those of commercial probiotic yeast, <italic>Saccharomyces boulardii</italic> MYA-796. To further explore the potential to survive in the host GI tract, biochemical activities, hydrophobicity assay, biofilm formation, auto-aggregation analysis, and phenol tolerance of the strains were assessed. <italic>K. marxianus</italic> A4 exhibited the best survivability among all tested strains, including the clinically proven probiotic yeast strain <italic>S. boulardii</italic> MYA-796 (<italic>p</italic> = 0.014) in the artificial GI tract ranging from pH 2.0 to 7.5. In addition, the five <italic>K. marxianus</italic> strains and <italic>S. boulardii</italic> MYA-796 displayed different assimilation of lactose, xylitol, D-sorbitol, and DL-lactate, indicating that <italic>K. marxianus</italic> metabolized a wide range of substances and, thus, might be more feasible to nourish themselves in the host GI tract for survival. <italic>K. marxianus</italic> strains showed a greater hydrophobicity of cell surface, abilities to biofilm formation and auto-aggregation, and phenol tolerance than <italic>S. boulardii</italic> MYA-796, suggesting greater potential for survival in the host GI tract.</p>