Evaluation and Optimization of Extracellular Digestive Enzymes from Bacillus spp. Isolated from Curds

Abstract

Objective: The aim of the present study was to evaluate the digestive enzyme activity of the four spp. and to optimize the physical parameters. Methods:The enzymes were produced by submerged fermentation supplementing enzyme specific substrates. The fermentation broths were centrifuged and the supernatants were used as source of crude enzyme. Amylase activity was determined by 3, 5-dinitro salicylic acid method using starch as substrate while copper soap method was used to evaluate lipase activity. Further, protease activity was measured by Lowry's method; whereas, phytase activity was assayed using sodium phytate as substrate. All the enzymes were optimized for pH, temperature and substrate concentration. The total protein content per one mL of the crude enzyme in the supernatant was quantified by Lowry's method.Results: All the four tested isolates B. subtilis GS 1, B. cereus GS 3, B. cereus GS 199 and B. subtilis GS 547 showed high extracellular digestive enzyme activity at pH range 5 to 8 and temperature 20 to 50°C. Conclusion:The four tested B. subtilis GS 1, B. cereus GS 3, B. cereus GS 199 and B. subtilis GS 547 could be promising extracellular digestive enzyme producing isolates. Further, evaluation of in vivo efficacy and safety in animal models and clinical trials would be helpful in assisting digestive enzyme deficiencies using these extracellular enzyme preparations or whole cell bacteria.