Enabling technologies for in situ biomanufacturing using probiotic yeast

Saccharomyces boulardii (Sb) is a Generally Regarded As Safe (GRAS) probiotic yeast currently used to alleviate symptoms from various gastrointestinal diseases. Sb is a promising platform for probiotic and biotherapeutic engineering as it is the only probiotic eukaryote and carries with it a unique set of advantages compared to bacterial strains, including resistance to phage, high protein secretion abilities, and intrinsic resistance to antibiotics. While engineered Sb has not been studied as extensively as its close relative Saccharomyces cerevisiae (Sc), many genetic engineering tools developed for Sc have also shown promise in Sb. In this review, we address recent research to develop tools for genetic engineering, colonization modulation, biomarker sensing, and drug production in Sb. Ongoing efforts, especially those that overcome gut-specific challenges to engineered performance, are highlighted as they advance this chassis as a scalable platform for treating gastrointestinal diseases.