Abstract

Ustilago maydis FBD12 is a phytopathogenic fungus that grows in submerged environments and produces different metabolites, such as glycolipids (biosurfanctants), cyclic peptides, tryptophan derivatives, and enzymes. Biosurfactants are molecules with a high surface activity, as well as emulsifying properties. They are secondary metabolites whose main physiological role is to support the growth of microorganisms in water-immiscible substrates, through the reduction of the superficial tension of the interface. In the present study, the production of glycolipids by U. maydis FBD12 was investigated during its growth in fish and soy oils. The highest growth was observed at the 7^th day of incubation with 16.8 and 7.25 g/L of biomass in fish and soy oils, respectively. An amount of 18.3 mg/100mL of glycolipid extract was obtained for fish oil, with an antioxidant capacity of 350 µMol ET/mL and a reduction in the minimum inhibitory concentration (MIC) towards S. aureus and S. Typhimurium of 25%. MIC decreased in 75% forStaphylococcus aureus when lipase was added to the fish oil culture medium. For soy oil, 9.6 mg/100mL of glycolipids were obtained with an antioxidant capacity of 232.5 µMol ET/mL and a MIC reduction of 25% in soy oil, which decreased 50% with the addition of lipase.

Key words: Antimicrobials, biosurfactants, lipase, reductors sugars, secondary metabolites, Ustilago.