alphaamülaasid

Alphaamülaasid are enzymes that catalyze the hydrolysis of internal alpha-1,4-glycosidic bonds in starch and related polymers, yielding maltose, maltotriose and dextrins. They are endo-acting, breaking the polysaccharide chain at internal sites rather than from the ends. Alpha-1,6-bonds remain largely intact, producing dextrins that can be further degraded by other enzymes. Most alphaamülaasid belong to glycoside hydrolase family 13 (GH13).

Natural sources include mammals (salivary and pancreatic amylases) and a broad range of plants and microorganisms. Industrial production relies on microorganisms such as Bacillus spp. and Aspergillus spp., with thermostable variants from Bacillus licheniformis and Bacillus amyloliquefaciens. Recombinant forms are common in modern biotechnology, enabling optimization of pH, temperature, and substrate specificity for specific processes.

Biochemically, alphaamülaasid require calcium ions for structural stability and often chlorine or other ions for activation depending on the source. They use a retaining double-displacement mechanism with two essential catalytic residues (aspartate and glutamate). Typical products are maltose, maltotriose, and limit dextrins; they can further act with other enzymes to deconstruct branched starch.

Applications span starch processing, brewing, baking, and biofuel production, as well as detergents and animal feed processing. In food technology, alphaamülaasid are used to liquefy starch, improve dough handling, and modify texture. In research and industry, engineered variants with altered thermostability, pH optima, and substrate range are common; production is largely via fermentation of selected microorganisms or recombinant expression.