Investigation of various agro-industrial wastes as carbon source for phytase production by Bacillus subtilis

In this study, phytase production by Bacillus subtilis ATCC 6633 is investigated using agro-industrial byproducts as the carbon source and key factors were optimized using one-factor-at-a-time method. The effect of various substrates including wheat bran, rice bran, corn husk, and light and dark soybean meal were studied. It was found that corn husk and wheat bran were the most effective carbon sources and the respective maximum phytase activities were 0.016 and 0.014 U/mL. A combination of corn husk and wheat bran at different concentrations was also explored to study the synergistic effect on phytase production. The highest activity of 0.012 U/mL was observed for the combination of 4% wheat bran and 1% corn husk, which was lower than the optimum phytase activity of the individual substrates. Hence, combining wheat bran and corn husk could not enhance phytase production. In addition, the effects of pH level and incubation temperature were assessed. It was found that pH 5 and temperature 35 °C were the most suitable levels showing the peaks of 0.017 and 0.014 U/mL for phytase activity, respectively. These findings provide a cost-effective approach to industrially produce phytase enzyme, supporting sustainable feed supplementation strategies.