Study of the transgalactosylation activity of ß-galactosidase from a new strain Kluyveromyces lactis 3

Beta-galactosidase (EC.3.2.1.23) is an important enzyme industrially used for the hydrolysis of lactose from milk and milk whey for several applications. Lately, the importance of this enzyme was enhanced by its galactosyltransferase activity, which is responsible for synthesis of transgalactosylated oligosaccharides that act as prebiotics with several beneficial effects on the consumers. ß-Galactosidase production by Kluyveromyces lactis 3 was studied in shake flask culture. The highest enzymatic activity was obtained at 10-th hour of the fermentation. The optimum temperature for transferase activity was 50°C. When incubated with 30% lactose in 50 mM phosphate buffer (pH 6.0) the enzyme can synthesize up to 41% galacto-oligosaccharides (GalOS). β-Galactosidase from strain Kluyveromyces lactis 3 produces mainly oligosaccharides with degree of polymerization (DP) 6 at 40°C and with DP 3 at 50°C.