Provided is an α-
amylase which has excellent amylolytic activity at low temperatures and further has excellent stability at low pHs and / or in the presence of a chelating agent. α-
Amylase mutants A1, B1, C1, D1, and E1 derived from the following parent amylases: an α-
amylase A having at least 90%
sequence identity to the
amino acid sequence of SEQ ID NO: 4; an α-
amylase B having at least 90%
sequence identity to the
amino acid sequence of SEQ ID NO: 6; an α-amylase C having at least 90%
sequence identity to the
amino acid sequence of SEQ ID NO: 8; an α-amylase D having at least 90% sequence identity to the amino acid sequence of SEQ ID NO: 10; and an α-amylase E having at least 90% sequence identity to the amino acid sequence of SEQ ID NO: 12, respectively, wherein the mutants A1 to E1 each comprises deletion of amino acid residues at two positions selected from the group consisting of positions corresponding to positions 178 to 181 according to the
numbering of SEQ ID NO: 1, and substitution of amino acid residues at three or more positions selected from the group consisting of positions corresponding to positions 178, 181, 238, 239, 240, 126, 129, and 201 according to the
numbering of SEQ ID NO: 2, the substitution including at least the following a) to e): a) in A1, 178H, 181E or 181Q, and 239Q; b) in B1, 178H, 181E or 181Q, and 239Q; c) in C1, 178H, 181E or 181Q, 238F, and 239Q; d) in D1, substitution at three or more positions selected from the group consisting of 178H, 181E or 181Q, 238F, and 239Q; and e) in E1, substitution at three or more positions selected from the group consisting of 178H, 181E or 181Q, 238F, 239Q, and 240F.