Abstract
beta Galactosidase from Aspergillus oryzae was immobilized on an inexpensive bioaffinity support, (concanavalin A) Con A-cellulose. The mode of interaction between Con A-cellulose and beta galactosidase is shown by Fourier transform infrared spectroscopy. Con A-cellulose adsorbed and crosslinked beta galactosidase preparation retained 78% of the initial activity. Soluble and immobilized beta galactosidase showed the same pH-optimum at pH 4.6. The temperature-optimum was increased from 50 to 60 degrees C for the immobilized beta galactosidase. The immobilized enzyme had higher thermal stability at 60 degrees C. The crosslinked adsorbed enzyme retained 80 and 70% of the original enzyme activity in the presence of 3% calcium chloride and 3% galactose, respectively. Moreover, the adsorbed crosslinked and adsorbed beta galactosidase exhibited 84 and 75% enzyme activity even after their sixth repeated use, respectively. The crosslinked adsorbed enzyme retained 93% activity after I month storage while the native enzyme showed only 63% activity under similar incubation conditions. Immobilized beta galactosidase showed higher lactose hydrolysis from Solution in batch process it 60 degrees C as compared to its hydrolysis at 50 degrees C. The continuous hydrolysis of lactose was appreciably different at various flow rates. Thus, the reactor filled with crosslinked Con A-cellulose adsorbed beta galactosidase could be successfully employed for the continuous hydrolysis of lactose from milk and whey. (C) 2010 Elsevier B.V. All rights reserved.