MFS-type efflux pump; part of the gene cluster that mediates the biosynthesis of mannosylerythritol lipids (MELs), surface-active substances that enhance the availability of water-insoluble substrates (PubMed:16885300, PubMed:24835306). Mannosylerythritol lipid production is responsible for hemolytic activity of Ustilago maydis (PubMed:16885300). MMF1 is directly involved in the secretion of MELs (PubMed:16885300, PubMed:24835306). Impairs the secretion of mannosylerythritol lipids (MELs). MELs not only have high potential as eco-friendly biosurfactants due to their excellent surface activity, but also have attracted considerable recent interest because of thei runique properties, including self-assembly, anti-tumor and cell differentiation induction activities, and moisturizing and hair-repairing properties. Belongs to the major facilitator superfamily.