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Cellulose is an organic compound with the formula (C6H10O5)n, a polysaccharide consisting of

a linear chain of several hundred to many thousands of (1!") lin#ed $%glucose units& Cellulose

is an important structural component of the primary cell wall of green plants, many forms of

algae and the oomycetes& 'ome species of  acteria secrete it to form iofilms&Cellulose is the

most aundant organic polymer on arth& *he cellulose content of cotton fier is +0, that of

wood is "0-50 and that of dried hemp is appro.imately "5&Cellulose is mainly used to produce paperoard and paper & 'maller /uantities are converted into

a wide variety of derivative products such as cellophane and rayon& Conversion of cellulose from

energy crops into iofuels such as cellulosic ethanol is under investigation as an alternative fuel

source& Cellulose for industrial use is mainly otained from wood pulp and cotton&

'ome animals, particularly ruminants and termites, can digest cellulose with the help of

symiotic micro%organisms that live in their guts, such as *richonympha& n humans, cellulose

acts as a hydrophilic ul#ing agent for feces and is often referred to as a dietary fier &

HistoryCellulose was discovered in 1232 y the 4rench chemist nselme ayen, who isolated it from

 plant matter and determined its chemical formula&

 The arrangement of

cellulose and other

polysaccharides in a

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A triple strand of cellulose

showing the hydrogen

bonds (cyan lines)

between glucose strands

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Structure and properties

Cellulose has no taste, is odorless, is hydrophilic with the contact angle of 70-30,8139 is insolule

in water  and most organic solvents, is chiral and is  iodegradale& t can e ro#en down

chemically into its glucose units y treating it with concentrated acids at high temperature&

Cellulose is derived from $ %glucose units, which condense through (1!")%glycosidic onds& 

*his lin#age motif contrasts with that for :(1!")%glycosidic onds present in starch, glycogen,

and other carohydrates& Cellulose is a straight chain polymer; unli#e starch, no coiling or

 ranching occurs, and the molecule adopts an e.tended and rather stiff rod%li#e conformation,

aided y the e/uatorial conformation of the glucose residues& *he multiple hydro.yl groups on

the glucose from one chain form hydrogen onds with o.ygen atoms on the same or on a

neighor chain, holding the chains firmly together side%y%side and forming microfibrils with

high tensile strength& *his confers tensile strength in cell walls, where cellulose microfirils are

meshed into a polysaccharide matrix&

A triple strand of cellulose showing the hydrogen bonds (cyan lines) between

glucose strands

Cotton bres represent the purest natural form of cellulose, containing more than

9! of this polysaccharide.

Compared to starch, cellulose is also much more crystalline& <hereas starch undergoes a

crystalline to amorphous transition when heated eyond 60-=0 >C in water (as in coo#ing),

cellulose re/uires a temperature of 370 >C and pressure of 75 ?a to ecome amorphous in

water&81"9

'everal different crystalline structures of cellulose are #nown, corresponding to the location of

hydrogen onds etween and within strands& @atural cellulose is cellulose , with structures : 

and & Cellulose produced y acteria and algae is enriched in : while cellulose of higher plants

consists mainly of & Cellulose in regenerated cellulose fiers is cellulose & *he conversion of

cellulose to cellulose is irreversile, suggesting that cellulose is metastale and cellulose

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is stale& <ith various chemical treatments it is possile to produce the structures cellulose

and cellulose A&8159

?any properties of cellulose depend on its chain length or  degree of polymeriBation, the numer

of glucose units that ma#e up one polymer molecule& Cellulose from wood pulp has typical chain

lengths etween 300 and 1=00 units cotton and other plant fiers as well as acterial cellulosehave chain lengths ranging from 200 to 10,000 units&869 ?olecules with very small chain length

resulting from the rea#down of cellulose are #nown as cellode.trins in contrast to long%chain

cellulose, cellode.trins are typically solule in water and organic solvents&

lant%derived cellulose is usually found in a mi.ture with hemicellulose, lignin, pectin and other

sustances, while acterial cellulose is /uite pure, has a much higher water content and higher

tensile strength due to higher chain lengths&869;332"

Cellulose is solule in 'chweiBerDs reagent, cupriethylenediamine (C$),

cadmiumethylenediamine (Cado.en),  N%methylmorpholine N%o.ide, and lithium chloride E

dimethylacetamide&8169 *his is used in the production of regenerated celluloses (such as viscose 

and cellophane) from dissolving pulp& Cellulose is also solule in many #inds of  ionic li/uids&81=9

Cellulose consists of crystalline and amorphous regions& Fy treating it with strong acid, the

amorphous regions can e ro#en up, therey producing nanocrystalline cellulose, a novel

material with many desirale properties&8129 Gecently, nanocrystalline cellulose was used as the

filler phase in io%ased polymer  matrices to produce nanocomposites with superior thermal and

mechanical properties&81+9

"rocessing

Assay

iven a cellulose%containing material, the carohydrate portion that does not dissolve in a 1=&5

solution of sodium hydro.ide at 70 >C is α cellulose, which is true cellulose8clarification needed 9&

cidification of the e.tract precipitates β cellulose& *he portion that dissolves in ase ut does

not precipitate with acid is γ cellulose8citation needed 9&

Cellulose can e assayed using a method descried y Ipdegraff in 1+6+, where the fier is

dissolved in acetic and nitric acid to remove lignin, hemicellulose, and .ylosans& *he resulting

cellulose is allowed to react with anthrone in sulfuric acid& *he resulting coloured compound is

assayed spectrophotometrically at a wavelength of appro.imately 635 nm&

n addition, cellulose is represented y the difference etween acid detergent fier ($4) and

acid detergent lignin ($J)&

#iosynthesis

n vascular plants cellulose is synthesiBed at the  plasma memrane  y rosette terminal comple.es

(G*Cs)& *he G*Cs are he.americ protein structures, appro.imately 75 nm in diameter, that

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contain the cellulose synthase enBymes that synthesise the individual cellulose chains&8709 ach

G*C floats in the cellDs plasma memrane and spins a microfiril into the cell wall&

G*Cs contain at least three different cellulose synthases, encoded y CesA genes, in an un#nown

stoichiometry&8719 'eparate sets of CesA genes are involved in primary and secondary cell wall

 iosynthesis& *here are #nown to e aout seven sufamilies in the CesA superfamily& *hesecellulose synthases use I$%glucose to form the (1!")%lin#ed cellulose&8779

Cellulose synthesis re/uires chain initiation and elongation, and the two processes are separate&

CesA glucosyltransferase initiates cellulose polymeriBation using a steroid  primer, sitosterol%

 eta%glucoside, and I$%glucose&8739 Cellulose synthase utiliBes I$%$%glucose precursors to

elongate the growing cellulose chain&  cellulase may function to cleave the primer from the

mature chain&

Cellulose is also synthesised y animals, particularly in the tests of ascidians (where the cellulose

was historically termed tunicine) although it is also a minor component of mammalian 

connective tissue&87"9

#rea$down (cellulolysis)

Cellulolysis is the process of rea#ing down cellulose into smaller polysaccharides called

cellode.trins or completely into glucose units this is a hydrolysis reaction& Fecause cellulose

molecules ind strongly to each other, cellulolysis is relatively difficult compared to the

 rea#down of other polysaccharides&8759 However, this process can e significantly intensified in

a proper solvent, e&g& in an ionic li/uid& 8769 ?ost mammals have only very limited aility to

digest dietary fires such as cellulose& 'ome ruminants li#e cows and sheep contain certain

symiotic anaeroic acteria (li#e Cellulomonas) in the flora of the rumen, and these acteria

 produce enBymes called cellulases that help the microorganism to rea# down cellulose the rea#down products are then used y the acteria for proliferation& *he acterial mass is later

digested y the ruminant in its digestive system (stomach and small intestine)& 'imilarly, lower

termites contain in their hindguts certain flagellate  protoBoa which produce such enBymes higher 

termites contain acteria for the Ko& 'ome termites may also produce cellulase of their own& 87=9 

4ungi, which in nature are responsile for recycling of nutrients, are also ale to rea# down

cellulose&

*he enBymes utiliBed to cleave the glycosidic lin#age in cellulose are glycoside hydrolases 

including endo%acting cellulases and e.o%acting glucosidases& 'uch enBymes are usually secreted

as part of multienByme comple.es that may include doc#erins and carohydrate%indingmodules&8729

%emicellulose

&ain article' %emicellulose

Hemicellulose is a polysaccharide related to cellulose that comprises aout 70 of the iomass

of most plants& n contrast to cellulose, hemicellulose is derived from several sugars in addition

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to glucose, especially .ylose  ut also including mannose, galactose, rhamnose, and arainose&

Hemicellulose consists of shorter chains - around 700 sugar units& 4urthermore, hemicellulose is

 ranched, whereas cellulose is unranched&

eriaties

*he hydro.yl groups (%OH) of cellulose can e partially or fully reacted with various reagents to

afford derivatives with useful properties li#e mainly cellulose esters and cellulose ethers (%OG)&

n principle, though not always in current industrial practice, cellulosic polymers are renewale

resources&

ster derivatives include;

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Applications

See also' dissoling pulp and pulp (paper)

 This section does not cite any references or sources. "lease help

improe this section by adding citations to reliable sources. *nsourced

material may be challenged and remoed. (January 2015)

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Cellulose for industrial use is mainly otained from wood pulp and cotton&869 *he #raft process is

used to separate cellulose from lignin, another maKor component of plant matter&

• "aper products' Cellulose is the ma+or constituent of paper, paperboard, andcard stoc$.

• ibers' Cellulose is the main ingredient of te-tiles made from cotton, linen,and other plant bers. t can be turned into rayon, an important ber that hasbeen used for te-tiles since the beginning of the /th century. #othcellophane and rayon are $nown as 0regenerated cellulose bers01 they areidentical to cellulose in chemical structure and are usually made fromdissoling pulp ia iscose. A more recent and enironmentally friendlymethod to produce a form of rayon is the 2yocell process.

• Consumables' &icrocrystalline cellulose (345i) and powdered cellulose(345ii) are used as inactie llers in drug tablets6/97 and as thic$eners andstabili8ers in processed foods. Cellulose powder is, for e-ample, used in

raft:s "armesan cheese to preent ca$ing inside;of the pac$age.

• Science' Cellulose is used in the laboratory as a stationary phase for thinlayer chromatography. Cellulose bers are also used in li<uid ltration,sometimes in combination with diatomaceous earth or other ltration media,to create a lter bed of inert material.

• 3nergy crops'

&ain article' 3nergy crop

 The ma+or combustible component of non;food energy crops is cellulose, with

lignin second. =on;food energy crops produce more usable energy than

edible energy crops (which hae a large starch component), but still compete

with food crops for agricultural land and water resources. 6>7 Typical non;food

energy crops include industrial hemp (though outlawed in some countries),

switchgrass, Miscanthus, Salix  (willow), and Populus (poplar) species.

A strand of cellulose (conformation ?), showing the hydrogen bonds (dashed) within

and between cellulose molecules.

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• #iofuel' T*;@>, a strain of Clostridium bacteria found in 8ebra waste, canconert nearly any form of cellulose into butanol fuel.6>@76>/7

• #uilding material' %ydro-yl bonding of cellulose in water produces asprayable, moldable material as an alternatie to the use of plastics andresins. The recyclable material can be made water; and re;resistant. tproides sucient strength for use as a building material. 6>>7 Celluloseinsulation made from recycled paper is becoming popular as anenironmentally preferable material for building insulation. t can be treatedwith boric acid as a re retardant.

• &iscellaneous' Cellulose can be conerted into cellophane, a thin transparentlm. t is the base material for the celluloid that was used for photographicand moie lms until the mid;@9>s. Cellulose is used to ma$e water;solubleadhesies and binders such as methyl cellulose and carbo-ymethyl cellulose which are used in wallpaper paste. Cellulose is further used to ma$ehydrophilic and highly absorbent sponges. Cellulose is the raw material in themanufacture of nitrocellulose (cellulose nitrate) which is used in smo$elessgunpowder.

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