Cyberlindnera jadinii and Kluyveromyces lactis, two fungi used in food processes, have potential probiotic effects on gut inflammation

ABSTRACT Many strains have been used and selected by the food industry for their capacities to ferment, produce flavors, or produce heterologous molecules. Very little is known about the diversity of foodborne yeasts and their potential effect on gut microbiota and gut health. We initiated a complete characterization of five strains belonging to five species with a long history of safe use in food: Cyberlindnera jadinii, Debaryomyces hansenii, Kazachstania unispora, Kluyveromyces lactis, and Pichia membranifaciens, with a focus on their capacity to protect against gut inflammation using an in vivo dextran sodium sulfate-induced colitis model in mice. C. jadinii and K. lactis living cells showed a clear reduction in mouse sensitivity to colitis in vivo. Interestingly, we observed that C. jadinii had the capacity to survive transit in the gut, while K. lactis did not. We demonstrated that C. jadinii was unable to efficiently adhere to epithelial cells and did not survive more than 24 to 48 h in the gut. Transcriptomic analysis using NanoString technology suggested a potential role of IL-8 through Mif and Fkbp5 in the effect of C. jadinii on the immune system. Bacterial and fungal microbiota characterization showed a modification of both microbiota after C. jadinii treatment, with a significant increase in positive microorganisms and a decrease in pathobionts. Altogether, these data suggest that both C. jadinii and K. lactis strains have potential as probiotic yeast strains to fight against inflammation in the gut, but further studies are needed to understand the mechanisms by which these strains act on gut health.IMPORTANCEThe food industry has always used many strains of microorganisms including fungi in their production processes. These strains have been widely characterized for their biotechnological value, but we still know very little about their interaction capacities with the host at a time when the intestinal microbiota is at the center of many pathologies. In this study, we characterized five yeast strains from food production which allowed us to identify two new strains with high probiotic potential and beneficial effects in a model of intestinal inflammation.