Production of phytase under solid-state fermentation using Rhizopus oryzae: Novel strain improvement approach and studies on purification and characterization

► Linseed oil cake and wheat bran was used as mixed substrate for solid state fermentation (SSF). ► Marked enhancement in phytase production after statistical optimization and novel strain improvement approach. ► High pH and thermal stability, resistance to proteolysis, broad substrate specificity, and high catalytic efficiency. ► An improved HPLC method was introduced for phytic acid determination.