Characterisation of a thermostable and proteolysis resistant phytase from Penicillium polonicum MF82 associated with the marine sponge Phorbas sp.

Abstract

Phytases are widely used in human and animal nutrition, aquaculture, soil amendment, and in the production of lower myo-inositol phosphates for clinical purposes. Some of these applications, especially feed industry require robust enzymes. Since the marine environments are less studied compared to terrestrial environments, we evaluated the extracellular phytase activity of 110 marine derived filamentous fungal (MDFF) strains previously isolated from sponge and sediment samples of the Turkey. MDFF strains were qualitatively screened for their extracellular phytase activities and P. polonicum MF82 phytase was further characterized following partial purification. Optimum pH and temperature were determined as 5.5 and 60 °C respectively. A significant relative phytase activity was observed in the presence of urea and acetone. However, there was no phytase activity followed by the treatment with Triton X-100 and Tween 80. Characterization studies revealed that P. polonicum MF82 phytase has superior properties for industrial use including wide pH and temperature range for activity, high optimum activity temperature, high thermal and pH stability, resistance to many enzyme inhibitors including various heavy metals, denaturants, detergents, proteases and organic solvents. Phytase extracellularly produced by P. polonicum MF82 strain presents a good candidate for commercial applications. This study demonstrates that the MDFF strains are prolific sources for phytase and presents the first report about the production and characterization of the phytase from a marine-derived P. polonicum strain.