Some Properties of Extracellular Protease from Bacillus licheniformis Lbbl-11 Isolated from “iru”, A Traditionally Fermented African Locust Bean Condiment

Thirty-five Bacillus isolates were obtained from traditionally fermented locust bean ( ̈iru ̈) in Akure, South-western part of Nigeria. Twelve of the bacillus isolates were identified as Bacillus licheniformis, twentyone as Bacillus subtilis and two as Bacillus cereus according to physiological and biochemical properties. The B. licheniformis isolates were selected for this study due to scarcity of reports on its use as starter culture for the fermentation of African locust bean. The B. licheniformis isolates were screened for proteolytic activity on skim milk agar. B. licheniformis isolate LBBL-11 exhibited the highest proteolytic activity with an average area of clear zone measuring 960 mm . This particular isolate was studied for protease production in an optimized 2 medium. Studies revealed that protease production by B. licheniformis LBBL-11 increased exponentially from 18 hour to 42 hour but reached a maximum at 48 hour. Studies on the physicochemical properties of the protease showed that the optimum temperature for the protease activity was 60°C. The enzyme was found to be 95% stable at 60°C after 60 minutes of incubation while at 70°C, it was about 60% stable. The optimum pH of the protease was 8.0 and the enzyme was stable over a wide range of pH 5.0-11.0 though a decrease of about 30% and 18% if its original activity was observed at pH 5.0 and 6.0 respectively. B. licheniformis LBBL-11 is a promising Bacillus species that can be used as a starter culture for the production of fermented locust bean condiment ( ̈iru ̈) under controlled conditions.