The beta-galactosidase gene from Bacillus subtilis KL88 was cloned into Escherichia coli and the gene product characterized for its potential use in the dairy industry. The two recombinant plasmids that we obtanied encoded a beta-galactosidase with the same catalytic and:thermal characteristics as the native beta-galactosidase from B. subtilis. The recombinant beta-galactosidases exhibited high activity at low temperature (10 degrees C), with maximum activity at 50 degrees C and an optimum pH of 6.0. Its molecular weight was estimated to be 90 Kd. The restriction maps of the recombinant plasmids were constructed. The beta-galactosidase gene was located in a 2.3 Kb fragment.