Amino acid sequence alignment of fungal phytases or acid phosphatases around the mutated residues (indicated in boldface). Afum, A. fumigatus ATCC 13073 phytase; Anid, A. nidulans phytase; Ater, A. terreus 9A1 phytase; Anig, A. niger NRRL 3135 phytase; Mthe, Myceliophthora thermophila phytase; Plyc, Peniophora lycii phytase; Agro, Agrocybe pediades phytase; A2.5, A. niger pH 2.5 acid phosphatase; con1, consensus phytase-1. The amino acids thought to correlate with the low-pH phytase activity of the respective proteins and tested for pH optimum engineering of A. fumigatus and consensus phytases are boxed.