Production of β-Galactosidase from Cheese Whey Using Kluyveromyces marxianus CBS 6556

This work presents alternatives sources of carbon and nitrogen for production of beta-galactosidase by Kluyveromyces marxianus CBS 6556. The main goal was to evaluate the production of this enzyme in the presence of cheese whey and corn step liquor in shake flasks cultures. Preliminary results from an experimental design (2(5-1)) showed that Prodex-lac (R) and agitation weren't significant variables. For the purpose of optimizing the enzyme production, a new factorial design was used. The central composite rotational design (CCRD) had cheese whey (100 to 1,000 mL L-1), corn step liquor (0 to 18 g L-1) and temperature (25 to 45 degrees C) as independent variables. The optimum temperature for the enzyme production was found to be 31 degrees C when associated with 820 mL L-1 of cheese whey and 14.36 g L-1 of corn step liquor, after 24 hours of culture. In lower corn step liquor concentration (3.64 g L-1), the enzyme activity was 20.7% less, indicating that a nitrogen source is important to promote enzyme production.