A 2.7-kb HindIII fragment from Bacillus subtilis contains an open reading frame (ORF) encoding a protein with homology to an Escherichia coli phospho-beta-glucosidase B (PBG B). The B. subtilis gene was induced by aromatic beta-glucosides, as judged by Northern hybridization and could complement an E. coli bglB mutant. Immediately down-stream from this B. subtilis bglA gene, there was a partial ORF on the opposite strand which encoded a polypeptide with extensive homology to NADH dehydrogenase from an alkalophilic Bacillus. These genes were mapped to 340 degrees between hut and gnt on the B. subtilis chromosome. Disruption of these genes by insertion of a neomycin-resistance-encoding gene (neo) did not result in any phenotypic changes comparable to those found in E. coli mutants.