YEAST β-MANNANASE ACTIVITY

The aim of the research was to determine the mannan-degrading activity of yeasts cultures isolated from various sources and select strains with high β-mannanase activity. As a result of screening of 245 yeast strains, which are the representatives of 7 genera and 14 species, the active producers of extracellular β-mannanase were identified. To increase β-mannanase activity, the cultures were grown under submerged conditions using guar gum galactomannan as a carbon source and an inducer. β-Mannanase activity was determined by dinitrosalicylic method. The most active biosynthetic species were Cryptococcus albidus, C. gastricus, C. magnus, C. terreus, C. laurentii, Saccharomyces cerevisiae, Williopsis californica, Metschnikowia pulcherrima, Pichia anomala and P. guilliermondii. The activity in culture supernatant was ranged from 0.2 to 75 U/ml. α-Galactosidase activity was found in two strains (Debaryomyces polymorphus UCM Y-152 and Debaryomyces hansenii var. fabryi UCM Y-2400). None of the tested cultures demonstrated both β-mannanase and α-galactosidase activity, that is, they are unable to attack both the main and side chains of galactomannan.