Moesziomyces spp. cultivation using cheese whey: new yeast extract-free media, -galactosidase biosynthesis and mannosylerythritol lipids production

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 beta-galactosidase production by Moesziomyces spp. from different sugars (D-galactose, D-glucose and D-lactose), with D-galactose being the best beta-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.