Lipolytic activity of carotenogenic yeast isolated from the polish ecosystem

The production of lipolytic enzymes by 130 red yeast strains isolated from various environments in Poland was assessed. Based on two screening tests on Petri dishes, 12 yeast strains with the highest potential lipolytic activity were selected. All strains belonged to the genus Rhodotorula. Further analysis showed that the most efficient producer of extracellular lipases was Rhodotorula babjevae A-110 (CMIFS 163), with lipolytic activity ranging from 39.11 to 50.35 U/mL during batch cultures in flasks. After cultivating this strain in a 5-L laboratory bioreactor, the highest lipase activity (137.25 U/mL) was achieved after 48 h in a medium with sunflower oil. The Michaelis-Menten constant of the lipases was 4.55 × 10^-4 M. Maximum activity was observed at pH 7.5-8.0, with an optimal temperature of 37 °C at pH 8.0. Lipolytic enzymes were stable at 20, 30, and 40 °C, but butanol completely inactivated R. babjevae lipases. Following protein precipitation from the postculture liquid with ammonium sulfate, lipolytic activity reached 352.52 U/mL, 2.5-fold higher than in the supernatant after cultivation of R. babjevae in a bioreactor.