Bacterial beta-galactosidase, immobilized forms thereof, process for their preparation and use in the hydrolysis of lactose, and novel bacteria

摘要

A novel beta -galactosidase comprises an enzyme having a thermal stability such that when in purified form it has an activity half life of at least 11/2 hours at 55 DEG C, at least 1 hour at 60 DEG C and at least 10 minutes at 65 DEG C, as measured using ONPG as substrate, said enzyme being derived from a bacterium of species Bacillus stearothermophilus. There is also provided a process for the production of the novel beta -galactosidase, comprising culturing in a medium containing appropriate nutrients a micro-organism of species B. stearothermophilus having characteristics similar to or the same as the strains identified as NCIB 11407-11413, and which contains the beta -galactosidase of the invention. Additionally there is provided a process for the hydrolysis of lactose to a product comprising glucose and galactose which comprises contacting lactose with the beta -galactosidase of the invention e.g. at a temperature of at least 55 DEG C preferably at least 60 DEG C or especially about 65 DEG C.