P83: Production of phytase by microbial submerged fermentation and optimization of process conditions

Phytase is an important enzyme, which breaks down phytate, which is the major phosphorus source in plants. Phytate causes malnutrition in animals and humans by binding several divalent minor nutrients in the bodies and results in some health problems such as iron deficiency, tooth decay and bone weakness. Therefore, phytase has been used in diets as feed additive to increase the minor nutrient absorption for years. Moreover, phytase is also used in monogastritic animals' diets to decrease excessive phosphorus excretion in manure to prevent the reverse effects on the environment. However, the current production by solid state fermentation cannot meet the demand and limiting the use due to high cost. Therefore, this project is undertaken to increase phytase production in submerged fermentation, which is commercially more viable approach. In this study, the microbial strains reported in the literature were screened for the best yielded strain and Aspergillus ficuum was selected as the best producer. Moreover, growth parameters were optimized in 2-L bioreactors for the selected producer by surface response methodology as 33^oC, 4.5 pH, and 0.9 vvm. Currently the medium composition optimization is in progress.