The production of extracellular, thermostable a-amylase by Bacillus coagulans B49 was studied in solid state fermentation (SSF). Significant levels of amylase were produced in wheat bran moistened with tap water [22707 (U/g dry bacterial bran)]/salt solution (25692 U). A marked improvement in enzyme production was achieved by optimization of SSF conditions (6700 U). Variations in the phase of a-amylase production and titres were observed depending on the culture vessels (Flask - 25 000 U at 72 h; reactor - 26350 U at 48 h) and conditions (static 24 24946 U at 72 h; shake flask - 25263 at 48 h). Maximum enzyme production (26350 U) was recorded in an aerated reactor. Catabolite repression was not evident in SSF even at high glucose concentrations. Cultivation in large trays yielded art enzyme titre of 17515 U at 96 h.