glukoamylase

Glukoamylase, also known as glucoamylase or amyloglucosidase, is an exoglucosidase enzyme that cleaves starch and related alpha-linked polysaccharides from the non-reducing ends. It hydrolyzes both alpha-1,4 and alpha-1,6 glycosidic bonds to release glucose, enabling complete conversion of starch to glucose under suitable conditions. Unlike endoacting enzymes such as alpha-amylase, glucoamylase works progressively from chain ends, producing free glucose rather than a mix of dextrins.

The enzyme is produced by several microorganisms and some yeasts. Industrial preparations commonly come from fungal sources such as Aspergillus species, and from certain bacteria; these preparations may be produced commercially as liquid or solid forms and can be used alone or in combination with other starch-degrading enzymes. Some glucoamylases contain carbohydrate-binding modules that help them interact with solid starch granules, enhancing efficiency in processing starch.

Applications are broad within starch processing and fermentation. Glukoamylase is used to convert starch into glucose syrups and high-fructose syrups, a key step in sweetener production. It also supports ethanol production, brewing, and distillation by providing liberated glucose for fermentation. In animal feed and nutrition, it improves digestibility by increasing available glucose. In practice, glucoamylase is often employed after an initial stage of alpha-amylase action, working to finish hydrolysis and maximize glucose yield.

Optimum conditions vary by source and preparation, but many fungal glucoamylases operate best in mildly acidic environments (roughly pH 4–5) at moderately elevated temperatures (often around 50–60°C). Industrial variants may be engineered for greater thermostability or acid tolerance.