Xylanase

Function

Xylanases belong to the pentosanases, a group of enzymes that break down components of the cell wall matrix of plants (fibre).

• Xylanases break down xylan (also known as "wood gum") - a woody, gummy, mucous substance that accompanies the cellulose present in all plants. Wheat, for example, has a high content of xylan.
  Xylanes belong to the group of pentosanes (broken down by pentosanases. These again belong to the hemicelluloses (broken down by hemicellulases).

• Arabinofuranosidase is a special pentosanase which can break down various side chains of xylan molecules.

Application

Xylanases are usually used in conjunction with various other specific enzymes: 

• mainly as a baking enzyme to improve dough qualities (workability, stability) and to optimize the product (stabilizing of crust and volume) see also: baking mixtures.

• in the production of liquor and in the alcohol industry (xylanases unlock the mucilaginous substances in grain to utilize them for fermentation).

• in the manufacture of fruit juices and beverages.

Further applications:

• Feed additives
  These enzymes contribute to a better digestion of plant-derived feed by liberating the xylanes contained in plants.

• Starch production in textile and paper industry

Gene technology

Increasingly, the production of xylanases is performed with the aid of genetically modified micro-organisms. These genetically optimized organisms are predominantly cultures of fungi (Aspergillus and Trichoderma species), but also include some bacteria (Bacillus).

• In Europe alone, there are seven preparations of xylanases available that are produced with the aid of genetically modified micro-organisms. In several cases, these are preparations of combinations with other enzymes (e.g. glucanases, amylases).

• To date, one xylanase preparation that is manufactured with the aid of gene technology has been assessed by the European Food Safety Authority (EFSA) as a feed additive.

Labelling on food: Food enzymes are not regarded as ingredients and are not included on the list of ingredients. Therefore, labelling in regard to their production with genetically modified micro-organisms is not foreseen.

Labelling on feed: Enzyme additives are regarded as additives that must be declared on feed. However, additives that are produced in closed systems using genetically modified organisms are not subject as such to labelling requirements.