Galactanases

Galactanases are enzymes that catalyze the hydrolysis of galactan polysaccharides, breaking beta-1,4-galactosidic bonds to release galactose or shorter galacto-oligosaccharides. They act on galactans found in plant cell walls and on galactose-rich side chains in galactomannans such as guar and locust bean gum, as well as other galactose-containing polysaccharides in nature.

These enzymes can be endo-acting, cleaving internal bonds to rapidly reduce polymer size, or exo-acting, removing galactose units from the non-reducing ends. Substrates include linear beta-1,4-galactan and galactomannans with galactose substitutions, as well as related pectic or hemicellulosic polysaccharides that contain galactose-rich regions.

Galactanases are produced by a variety of microorganisms, notably bacteria and fungi, and are often secreted extracellularly to facilitate access to environmental polysaccharides. They are categorized within the broader group of glycoside hydrolases, with different enzymes showing varying substrate specificities and mechanisms across multiple enzyme families.

Applications and significance of galactanases lie in the processing and valorization of galactan-containing polysaccharides. They are used in biomass conversion and the refinement of plant-derived gums, in the production of galacto-oligosaccharides for potential prebiotic use, and in research on plant cell-wall structure and polysaccharide degradation. As components of enzymatic suites, galactanases contribute to the tailored modification of hemicelluloses for industrial and biotechnological purposes.