Mutant E. coli appa phytase enzymes and natural variants thereof, nucleic acids encoding such phytase enzymes, vectors and host cells incorporating same and methods of making and using same

A recombinant phytase having modified phytase activity said recombinant phytase comprising a modification selected from the group of modifications consisting of

• i) a modification of at least one amino acid residue(s) corresponding to residue(s) 26, 43, 46, 54, 73, 113, 126, 184, 228, 384 or 410 of a mature E. Coli phytase designated EBC18B2 of FIG. 12;
• ii) a modification of at least one amino acid residue located within 5 residues either upstream or downstream in linear sequence from the amino acid residue(s)corresponding to residue(s) 26, 43, 46, 54, 73, 113, 126, 184, 228, 384 or 410 of a mature E. Coli phytase designated EBC18B2 of FIG. 12;
• and
• iii) a modification of at least one amino acid residue which has its alpha carbon located within 6 Å of the alpha carbon of amino acid residues selected group of residue(s) corresponding to residue(s) 26, 43, 46, 54, 73, 113, 126, 184, 228, 384 or 410 of a mature E. Coli phytase designated EBC18B2 of FIG. 12. (Please indicate any others residues).