Abstract

A novel beta-propeller phytase producing thermophilic strain of Bacillus licheniformis was isolated. The culture conditions for production of phytase by B. licheniformis under shake flask culture were optimized to obtain high levels of phytase (0.267 U/ml). The optimum temperature and pH of the phytase from B. licheniformis (PhyC) were 55°C and 7.0, respectively. The enzyme exhibited good thermostability and pH stability in the presence of 1 mM CaCl₂. After treatment at 80°C, pH 7.0 for 10 min, the residual activity of PhyC was 57.36%. Over 80% of PhyC activity was retained after treatment by preincubation over a pH range of 6.5 to 9.0 for 1 h at 25°C. Substrate was very specific for sodium phytate and showed no activity on other phosphate esters. Its activity was greatly inhibited by EDTA and metal ions such as Cd²⁺, Mn²⁺, Cu²⁺ and Ba²⁺.

Key words: Bacillus licheniformis, phytase, production, optimization, characterization.