beta-Galactosidase production by Kluyveromyces marxianus cultured in shake flasks

beta-Galactosidase production by K. marxianus was studied in shake flasks. Enzyme production was strongly influenced by culture conditions determining oxygen transfer rates. Working volume turned out to be the most significant parameter affecting enzyme yields: the higher the volume, the higher the specific activity of the enzyme. The use of dehydrated whey (as the source of lactose) resulted in a large increase in the specific enzyme activity as compared with the use of pure lactose. This effect is likely due to a lower dissolved oxygen concentration along the fermentation. In the range of kL a between 40 and 90 h-1, enzyme activity did not seem to depend on kL a, whereas a drastic drop in the final specific enzyme activity was observed for kL a values above 90 h-1.