Partial Purification and Characterization of Microbial Phytases from Pseudomonas chlororaphis, Bacillus megaterium, and Agrobacterium radiobacter

Phytases are enzymes that hydrolyze the phosphate groups in phytic acid to release soluble phosphate. Among phytases, microbial phytases are preferred due to their high activity, low cost, and environmentally friendly properties. In this study, microbial phytases were obtained from Pseudomonas chlororaphis C37-A, Bacillus megaterium M-3, and Agrobacterium radiobacter A-16 isolates. The phytase enzymes were partially purified using ammonium sulfate precipitation, and their optimum pH and temperature conditions were subsequently determined The most suitable ammonium sulfate precipitation range in the partial purification process was determined as 60-80% for isolate M-3 and 40-60% for isolates C37-A and A-16.The specific activities and purification folds of the enzymes in these precipitation ranges were measured as 34.28EU/mg and 3.94 for M-3, 27.25EU/mg and 1.91 for C37-A, and 23.24EU/mg and 2.11 for A-16, respectively. SDS-PAGE analysis showed that the molecular weights of the enzymes were approximately 45 kDa. When tested for enzymatic performance, phytase obtained from P. chlororaphis C37-A showed its highest activity at 50°C and pH 8.0, while B. megaterium M-3 showed the best activity at 50°C and pH 6.0. The enzyme obtained from A. radiobacter A-16 reached the highest activity at 30°C and pH 6.0. These findings suggest that the phytase enzyme from P. chlororaphis prefers slightly alkaline conditions, whereas phytases from B. megaterium and A. radiobacter function better in mildly acidic environments. Overall, the varying environmental tolerances of these isolates support their potential use in developing microbial biofertilizers, especially for soils that are poor in phosphorus.