Bacillus halodurans was cultivated on wheat bran as a solid-state substrate and produced haloduracin, a bacteriocin, at about 245 AU per wheat bran. Supplementation of the bran with Lauria-Bertani broth decreased haloduracin production. However, production was stimulated by addition of Mg(2)SO(4) and K(2)HPO(4). The highest production was achieved at a wheat bran/moisture ratio of 1:1.8 and in the presence of 10% (w/w) Na(2)CO(3). Under optimum conditions, the organism produced about 3,000 AU per gram dry bran.