Growth and extracellular enzyme production by strains of Bacillus species isolated from fermenting African locust bean, iru

Adeiubigbe, E.Y. & Odunfa, S.A. 1990. Growth and extracellular enzyme production by strains of Bacillus species isolated from fermenting African locust bean, iru. Journal of Applied Bacteriology69, 662–671. Seven strains of Bacillus subtilis group, isolated from fermented African locust bean (iru), were screened for proteolytic activity. Three strains (BS2, BL2 and BP2), which were found to be highly proteolytic, were compared on the basis of growth and extracellular enzyme production in media with and without locust bean. AH had their optimum pH for growth between 7.0 and 9.0. The three strains produced varied amounts of amylase, polygalacturonase, galac-lanase and sucrase. The amounts of amylase and polygalacturonases produced by strain BS2 were significantly higher (at α= 0.5) than those of strains BL2 and BP2. None of the strains produced pectinmethylesterase in nutrient broth with or without African locust bean. Although the three strains were lipolytic on tributyrin agar plates, only trace amounts of lipase were detected titrimetrically in broth medium containing African locust bean. The three strains produced varying levels of sucrase and galactanases. Phytase activity was not detected in the broth culture of strain BS2. The presence of African locust bean in culture medium generally enhanced the production of extracellular enzymes significantly (at α= 0.05) in the three strains.