Biocontainment Strategies for In Vivo Applications of Saccharomyces Boulardii
International Conference on Microbiome Engineering
2023
6th International Conference on Microbiome Engineering
Poster Session
Poster Presentation Session A
Friday, December 8, 2023 - 4:50pm to 6:00pm
The human gastrointestinal tract is a complex and dynamic environment, playing a crucial role in human health. Microorganisms engineered to express a therapeutic activity have emerged as a novel modality to manage numerous diseases. Such advanced microbiome therapeutics (AMTs) must be contained within the treated individual. Hence safe and robust biocontainment strategies are required to prevent the proliferation of microbes outside the treated individual. Here we present the first biocontainment strategy for a probiotic yeast, demonstrating a multi-layered strategy combining an auxotrophic and environmental-sensitive strategy. We knocked out the genes THI6 and BTS1, causing thiamine auxotrophy and increased sensitivity to cold, respectively. The biocontained Saccharomyces boulardii showed restricted growth in the absence of thiamine above 1 ng/ml and exhibited a severe growth defect at temperatures below 20°C. The biocontained strain was well tolerated and viable in mice and demonstrated equal efficiency in peptide production as the ancestral non-biocontained strain. In combination, the data support that thi6â and bts1â enable biocontainment of S. boulardii, which could be a relevant chassis for future yeast-based AMTs.