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

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

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 abu ...

into

xylose Xylose ( , , "wood") is a sugar first isolated from wood, and named for it. Xylose is classified as a monosaccharide of the aldopentose type, which means that it contains five carbon atoms and includes an aldehyde functional group. It is deriv ...

, 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 embryophyte, terrestrial plant cell walls. Cellulose is crystalline, strong, an ...

, one of the major components of plant

cell walls A cell wall is a structural layer that surrounds some cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, and functi ...

: : Endohydrolysis of (1→4)-β-D-xylosidic linkages in xylans Xylanase plays a major role in

micro-organism A microorganism, or microbe, is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells. The possible existence of unseen microbial life was suspected from antiquity, with an early attestation in ...

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.;

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

s 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; it has Symbol (chemistry), 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 ...

-free bleaching of wood pulp prior to the

papermaking Papermaking is the manufacture of paper and cardboard, which are used widely for printing, writing, and packaging, among many other purposes. Today almost all paper is Pulp and paper industry, made using industrial machinery, while handmade pape ...

process, and the increased digestibility of

silage Silage is fodder made from green foliage crops which have been preserved by fermentation (food), fermentation to the point of souring. It is fed to cattle, sheep and other ruminants. The fermentation and storage process is called ''ensilage'', ' ...

(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 Decomposition, decomposing plant and food waste, recycling organic materials, and man ...

). Apart from its use in the

pulp and paper industry The pulp and paper industry comprises companies that use wood, specifically pulpwood, as raw material and produce pulp, paper, paperboard, and other cellulose-based products. Manufacturing process In the manufacturing process, pulp is intr ...

, 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 conditioners 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 Biofuel is a fuel that is produced over a short time span from Biomass (energy), biomass, rather than by the very slow natural processes involved in the formation of fossil fuels such as oil. Biofuel can be produced from plants or from agricu ...

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