A novel strain of Bacillus fusiformis, producing high amounts of vanillin from isoeugenol, was isolated from soil. Using 60% (v/v) isoeugenol as substrate and solvent and at pH 4.0, 37 degrees C and 180 rpm, vanillin was produced at 32.5 g l(-1) over 72 h. The unused isoeugenol was reusable.