Hydrolysis of D‐galactosides in an open tubular lactase reactor

Abstract

Lactose (β‐galactosidase) was attached to the inner surface of nylon tubing. Tubes of various lengths were used to bring about the hydrolysis of o‐nitrophenyl‐β‐D‐galactoside and of lactose in skim milk. The results with the former substrate were analyzed in the light of a theoretical treatment of Kobayashi and Laidler (Biotechnol. Bioeng., 16, 99, 1974), with the conclusion that the reaction is intermediate between diffusion‐free and completely diffusion‐controlled behavior. The results with skim milk show that with a single 46 m tube and continuous circulation, 90% of the lactose is removed within 20 hr. A battery of ten such tubes, with single passage, at a flow rate of 2 cm/sec, would remove more than 99% of the lactose in less than 40 min.