Scientists identified mutations that improved the ability of yeast to use xylose for biofuel production. By studying a specially engineered yeast strain, they found specific genetic changes that boosted xylose fermentation. Mutations in two genes, PBS2 and PHO13, were crucial for enhancing xylose utilization. Additionally, deleting the PHO13 gene alone improved xylose metabolism in yeast strains using a different xylose utilization pathway. These findings shed light on the genetic factors that influence xylose utilization in yeast, which is essential for efficient biofuel production from biomass.