Adaptive laboratory evolution of maltose utilisation in wild Irish isolates of Saccharomyces eubayanus.

Adaptive laboratory evolution enabled Irish S. eubayanus strains to metabolize maltose through MAL locus duplication and MalR mutations, with W307L mutation fully restoring maltose utilization.

• Why it matters: Understanding maltose metabolism in wild Irish isolates of S. eubayanus addresses gaps in knowledge about their genetic potential for brewing applications and their evolutionary adaptation to maltose-rich environments.
• What they did: Ten Irish strains were studied, with two passaged in maltose medium; genetic changes such as MAL locus duplication and MalR mutations were identified, and CRISPR-Cas9 was used to validate their effects.
• The result: Maltose utilization depends on MAL gene copy number and gain-of-function MalR mutations, enabling potential engineering of wild strains for brewing and biotechnological processes.