WHOLE-CELL ENZYME MICROENCAPSULATION OF ESCHERICHIA-COLI WITH OXYGEN-DEPENDENT INDUCIBLE NAR PROMOTER

As a means of integrating cell growth and immobilization, Escherichia coli with the cloned nar promoter on the pBR322 plasmid, which is maxi mally induced under anaerobic conditions in the presence of nitrate, w as immobilized in liquid-core alginate capsules and cultured to a high cell density. The total beta-galactosidase activity obtained by immob ilized cells was about 6 fold greater than that obtained by free cells . Using the immobilized beta-galactosidase in the whole cells, the sub strate lactose was hydrolyzed to glucose and galactose stably with a c onversion efficiency of more than 80% for 15 repeated batches at 30 de grees C for 5 days.