Determination of Proteolytic Activities of Bacillus species Isolated From Traditional Fermented Oil Bean Seed (UGBA: Pentaclethra macrophylla, Benth)

Abstract

Eighty samples of traditional fermented “ugba” (Pentaclethra macrophylla, Benth) wraps collected from eight markets in Umuahia were analyzed for proteolytic activities (by zone of inhibition in mm) of Bacillus species using two protein-based substrates: Skim Milk Agar and Nutrient Agar supplemented with 1% gelatin. 51 isolates were identified as B. subtilis, 18 as B. licheniformis and 11 as B. pumilus with Ariam Market having the highest mean count (mm) of 1.93±0.16. B. subtilis had the highest proteolytic activity (28.00±0.55) on Skim Milk Agar (P=.05) but together with B. licheniformis had the same level of proteolytic activity (26.00±0.00 and 26.00±0.55 respectively at P=.05) which is higher than B. pumilis (13.00±0.55) on Nutrient agar supplemented with 1% gelatin. However, B. licheniformis and B. pumulis had better proteolytic activities (26.00±0.55 and 13.00±0.55: P=.05) respectively on Nutrient agar supplemented with 1% gelatin than on Skim Milk Agar. The two potential protease producers that showed higher proteolytic activity were incubated at high temperature and result showed that B. subtilis proteolytic activity was optimum at (29.00±0.71) at 50°C while that of B. licheniformis was optimum (28.00±0.00) at 40°C (P=.05). Antimicrobial susceptibility of the Bacillus species showed that the three Bacillus species were most sensitive to Chloramphenicol (21.00±0.51) without any statistical difference followed by Gentamycin (20.00±0.31) but completely resistant to Rifampicin (0.00±0.0; P=.05). B. subtilis showed better proteolytic activity at a higher temperature and will be better suited for production processes in industries where thermophilic temperatures are needed.