Alpha-amylase variants stabilized against dimerization and/or multimerization, method for the production thereof, and detergents and cleansers containing these alpha-amylase variants

An α-amylase variant of the α-amylase of Bacillus sp. A 7-7 (DSM 12368) according to positions +1 to 484 of SEQ ID NO. 2 and having α-amylase activity, the variant having a plurality of amino acid substitutions with respect to the α-amylase starting molecule,

• wherein the α-amylase variant differs from the α-amylase starting molecule by substitution of a plurality of predetermined starting amino acid residues at the surface of the molecule making a neutral or positively polar or charged contribution to the electrostatic potential of said molecule with more negatively polar or negatively charged substituted amino acid residues, thereby providing increased stability to aggregate formation,
• wherein the amino acid substitutions are chosen from the following substitutions:
• Starting
• Substituted
• amino
• amino
• acid
• acid
• Arg (R)
• K, Y, C, H, G, A, V, L, I, M, F,
• W, P, S, T, N, Q, E or D
• Lys (K)
• Y, C, H, G, A, V, L, I, M, F, W,
• P, S, T, N, Q, E or D
• Trp (W)
• P, S, T, N, Q, E or D
• Pro (P)
• S, T, N, Q, E or D
• Ser (S)
• T, N, Q, E or D
• Thr (T)
• N, Q, E or D
• Asn (N)
• Q, E or D
• Gln (Q)
• E or D
• wherein said starting amino acid residues are selected from the following positions:
• 83, 94, 118, 154, 172, 176, 260, 283, 302, 320, 323, 376, 400, 419, 422,
• 439, 444, 445, 459, and 463,
• in each case indicated in the numbering of the mature protein according to SEQ ID NO. 2,
• wherein the amino acid substitutions are limited to two or more of the listed positions, and
• wherein the number of substitutions is up to 20.