Résumé
Some of the regulatory features of the Bacillus subtilis beta- mannanase operon [man A] have been investigated. The results proved that man A is extremely sensitive to cell growth state as a modulator, glucose, as a catabolite repressor and galactomannan as an inducer. It seems likely that catabolite repression of man A is mediated by two routes, one of which is commonly responsive to readily metabolizable carbon sources while the other is specific to glucose. At optimized physiological condition, the maximum enzyme yield [34 U/ml] was achieved within 4 hours. It was also demonstrated that mutated sporulation genes may block spore formation without affecting enzyme production. This would allow an extended enzyme production phase especially in continuous culture