Endo-1,4-β-xylanase (EC 3.2.1.8, systematic name 4-β-D-xylan xylanohydrolase) is any of a class of

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

s that degrade the linear polysaccharide

xylan Xylan (; ) ( CAS number: 9014-63-5) is a type of hemicellulose, a polysaccharide consisting mainly of xylose residues. It is found in plants, in the secondary cell walls of dicots and all cell walls of grasses. Xylan is the third most abundan ...

into xylose, thus breaking down

hemicellulose A hemicellulose (also known as polyose) is one of a number of heteropolymers (matrix polysaccharides), such as arabinoxylans, present along with cellulose in almost all terrestrial plant cell walls.Scheller HV, Ulvskov Hemicelluloses.// Annu Rev ...

, one of the major components of plant cell walls: : Endohydrolysis of (1→4)-β-D-xylosidic linkages in xylans Xylanase plays a major role in

micro-organism A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...

s thriving on plant sources for the degradation of plant matter into usable nutrients. Xylanases are produced by fungi, bacteria, yeast, marine algae, protozoans, snails, crustaceans, insect, seeds, etc.; mammals do not produce xylanases. However, the principal commercial source of xylanases is filamentous fungi. Commercial applications for xylanase include the

chlorine Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine i ...

-free bleaching of wood pulp prior to the papermaking process, and the increased digestibility of

silage Silage () is a type of fodder made from green foliage crops which have been preserved by fermentation to the point of acidification. It can be fed to cattle, sheep and other such ruminants (cud-chewing animals). The fermentation and storage ...

(in this aspect, it is also used for fermentative

composting Compost is a mixture of ingredients used as plant fertilizer and to improve soil's physical, chemical and biological properties. It is commonly prepared by decomposing plant, food waste, recycling organic materials and manure. The resulting m ...

). Apart from its use in the pulp and paper industry, xylanases are also used as food additives to poultry; in wheat flour for improving dough handling and quality of baked product

for the extraction of coffee, plant oils, and starch; in the improvement of nutritional properties of agricultural silage and grain feed; and in combination with pectinase and cellulase for clarification of fruit juices and degumming of plant fiber sources such as flax, hemp, jute, and ramie. A good quantity of scientific literature is available on key features of xylanase enzymes in biotechnology ranging from their screening in microbial sources to production methods, characterization, purification and applications in commercial sector. High resilience to heating is required for some applications of xylanase, which can be achieved through selection of suitable microbial enzymes or by cyclization of the termini by SpyCatcher, SpyTag/SpyCatcher reaction. Additionally, xylanase is the key ingredient in the

dough conditioner A dough conditioner, flour treatment agent, improving agent or bread improver is any ingredient or chemical added to bread dough to strengthen its texture or otherwise improve it in some way. Dough conditioners may include enzymes, yeast nutrients ...

s s500 and us500 manufactured by . These enzymes are used to improve the dough's workability and absorption of water. In the future, xylanase may be used for the production of biofuel from unusable plant material. *

Synonyms

Endo-(1→4)-β-xylan 4-xylanohydrolase, endo-1,4-xylanase, endo-1,4-β-xylanase, β-1,4-xylanase, endo-1,4-β-D-xylanase, 1,4-β-xylan xylanohydrolase, β-xylanase, β-1,4-xylan xylanohydrolase, β-D-xylanase

Synonyms

References

Further reading