Variants of B. licheniformis alpha-amylase advantageously exhibit improved enzymatic performance. Suitable variants include those with an altered charge distribution on the surface of the enzyme or with altered active site residues. Structural modeling can inform the choice of amino acid modifications so that modified amino acids correspond to residues found in more active alpha amylases, for example. Compositions comprising the variants are useful in methods of cleaning surfaces, laundering textiles, desizing, treating starch, e.g., liquefaction and saccharification, and hydrolyzing biofilms off various substrates.
