Conditions for the production of bacterial alginate-specific lyase (A1-III) by Bacillus subtilis transformed with an inducible secretion vector pISA412 harboring the A1-III gene from a bacterium (Flavobacterium sp.) of strain A1 were studied. Galactose at around 3% was found as the most efficient carbon source in the pH region between 7.0-8.5. A higher amount of potassium phosphate was required to repress degradation of A1-III produced in medium. Under the most preferable culture conditions determined, production of the lyase reached approximately 0.3 mg/ml. The properties of A1-III purified from the medium were comparable with those of A1-III present in strain A1 in terms of molecular size, substrate specificity and in N-terminal amino acid sequence.