Abstract

Twelve strains of Bacillus licheniformis isolated from traditionally fermented African locust bean (iru) were evaluated in respect to production of protease on skim milk agar. B. licheniformis LBBL-11 exhibited the highest proteolytic activity with a diameter of clear zone measuring 35.0 mm. Production of protease from B. licheniformis LBBL-11 was further studied by growing the strain on nutrient broth. Maximum protease production was 18.4 U/ml  at 48 hour of growth which coincided with the end of exponential phase. The protease from this Bacillus sphad optimum pH of 8.0 and was stable over a wide pH range of 5.0 - 11.0. The optimum temperature for the protease activity was 60^oC. The enzyme was 95% stable at 60^oC after 60 min of incubation. These properties indicate possible application of B. licheniformis LBBL-11 as potential starter culture for the fermentation of African locust bean under controlled conditions of temperature and pH.

Key words: Fermented locust bean, iru, protease, thermostable, Bacillus licheniformis