Mannosylerythritol lipids (MELs) are biosurfactants with excellent biochemical properties and a wide range of potential applications. However, high production costs, low productivity and unsatisfactory scale-up production have hampered commercial adoption. Herein, we report for the first time the β-galactosidase production by Moesziomyces spp. from different sugars (D-galactose, D-glucose and D-lactose), with D-galactose being the best β-galactosidase inducer, with 11.2 and 63.1 IU/mg biomass , for Moesziomyces aphidis 5535 T and Moesziomyces antarcticus 5048 T , respectively. The production of this enzyme allows to break down D-lactose and thus to produce MEL directly from D-lactose or cheese whey (a cheese industry by-product). Remarkably, when CW was used as sole media component (carbon and mineral source), in combination with waste frying oil, MEL productivities were very close (1.40 and 1.31 g MEL /L/day) to the ones obtained with optimized medium containing yeast extract (1.92 and 1.50 g MEL /g susbtrate ), both for M. antarcticus and M. aphidis . The low-cost, facile and efficient process which generates large amounts of MELs potentiates its industrialization. Supplementary Information The online version contains supplementary material available at 10.1007/s13399-022-02837-y.