biostudies-literaturede Carvalho BTVlaams Instituut voor BiotechnologieVlaams Instituut voor Biotechnologie (VIB)e0032524https://www.ebi.ac.uk/biostudies/studies/S-EPMC11218656biostudies-literatureUnknown90(6)<i>Saccharomyces boulardii</i> has been a subject of growing interest due to its potential as a probiotic microorganism with applications in gastrointestinal health, but the molecular cause for its probiotic potency has remained elusive. The recent discovery that <i>S. boulardii</i> contains unique mutations causing high acetic acid accumulation and inhibition of bacterial growth provides a possible clue. The natural <i>S. boulardii</i> isolates Sb.P and Sb.A are homozygous for the recessive mutation <i>whi2</i>^S270* and accumulate unusually high amounts of acetic acid, which strongly inhibit bacterial growth. However, the homozygous <i>whi2</i>^S270* mutation also leads to acetic acid sensitivity and acid sensitivity in general. In the present study, we have constructApplied and environmental microbiologyEnhancing probiotic impact: engineering <i>Saccharomyces boulardii</i> for optimal acetic acid production and gastric passage tolerance.PMC11218656GC02-C06Thevelein JMSubotic AVermeire SVandecruys PDeleu Sde Carvalho BTfalseEnhancing probiotic impact: engineering <i>Saccharomyces boulardii</i> for optimal acetic acid production and gastric passage tolerance.<i>Saccharomyces boulardii</i> has been a subject of growing interest due to its potential as a probiotic microorganism with applications in gastrointestinal health, but the molecular cause for its probiotic potency has remained elusive. The recent discovery that <i>S. boulardii</i> contains unique mutations causing high acetic acid accumulation and inhibition of bacterial growth provides a possible clue. The natural <i>S. boulardii</i> isolates Sb.P and Sb.A are homozygous for the recessive mutation <i>whi2</i>^S270* and accumulate unusually high amounts of acetic acid, which strongly inhibit bacterial growth. However, the homozygous <i>whi2</i>^S270* mutation also leads to acetic acid sensitivity and acid sensitivity in general. In the present study, we have construct2024-01-01T00:00:00Z2024 Jun2026-05-07T14:19:12.247Z2025-04-04T23:54:49.584ZS-EPMC112186563875274810.1128/aem.00325-24