An intracellular beta-glucosidase was purified from cell extracts of Bacillus circulans subsp. alkalophilus by NAD affinity and high-performance anion-exchange chromatographies. The enzyme was active against a wide range of aryl-beta-glucosides and beta-linked disaccharides. The structural gene for beta-glucosidase was cloned in Escherichia coli. The beta-glucosidase gene consisted of an open r...