Thermomyces lanuginosus CBS 395.62/b Strain as Rich Source of -Galactosidase Enzyme

Seventeen Thermomyces lanuginosus strains, cultivated on raffinose and sucrose, were ranked on the basis of -galactosidase activities. T. lanuginosus CBS 395.62/b strain showed the highest -galactosidase activity on both investigated carbohydrates. Several carbon sources were tested as potential inducers for the -galactosidase synthesis. On melibiose substrate -galactosidase activity was higher in the intracellular fraction than in the filtrate of the fermentation broth, although both values were very low and did not reach the value of 1 U/mL. Raffinose, sucrose and Lactosucrose proved to be inducers for -galactosidase production. The highest titer (about 30 U/mL) was achieved on 1 % sucrose and 0.45 % ammonium acetate. The optimum sucrose and ammonium acetate concentrations, at which about 90 U/mL -galactosidase activity was reached during an 8-day fermentation, were 3 and 0.9 %, respectively.