Properties of crude beta-galactosidase of Mucor hemiclonus and its application in lactose hydrolysis of some dairy by-products

ABSTRACT

Biochemical studies on the properties of acetone precipitated extracellular beta-galactosidase of M. humicolus indicated that the enzyme is notably thermostable expressing maximum activity at 60° and pH 3.0. The reaction progress with time was linear up to 30 minutes of incubation. The enzyme could effectively hydrolyze lactose present in some dairy by-products. Thus upon using enzyme level of 0.9 unit/ml the enzyme could hydrolyze 28.8%, 32.4%, 62.4%, 18.2% and 43.1% of lactose present in milk, whey, 1 1 diluted whey, whey permeate and 1 1 diluted whey permeate respectively, after 8 hr at 30°. At 40° and at the same enzyme level the percentage of lactose hydrolyzed reached 60.0%, 63.6%, 69.6% and 70.0% in whey permeate, whey, diluted permeate and diluted whey respectively. At the same temp. [40°] and by increasing enzyme concen. to 1.8 unit/ml, the lactose hydrolysis reached 64.4%, 84.0%, 77.0% and 86.8% of lactose present in the four substrates respectively. The results are discussed in the light of the application feasibility of this enzyme