Lactic acid bacterium F. sanfranciscensis impairs fitness of yeast M. humilis in a synthetic wheat sourdough medium.

F. sanfranciscensis impairs the fitness of M. humilis in a synthetic wheat sourdough medium, with co-culture reducing M. humilis growth compared to monoculture.

• Why it matters: Understanding microbial interactions in sourdough starters is crucial for controlling bread quality and ecosystem stability, especially given the presumed trophic relationship between these species.
• What they did: Researchers co-cultured M. humilis and F. sanfranciscensis in a controlled synthetic medium, using flow cytometry to measure cell viability and analyzing metabolite consumption, including amino acids and sugars.
• The result: F. sanfranciscensis was found to consume less maltose in co-culture and produce amino acids, indicating that their interaction is likely neutral or competitive, with strain identity influencing dominance and metabolite profiles.