Meta tags:

Headings (most frequently used words):

lignin, degradation, by, contents, history, composition, and, structure, biological, function, delignification, biosynthesis, biodegradation, pyrolysis, chemical, analysis, see, also, references, further, reading, external, links, fungi, bacteria,

Text of the page (most frequently used words):
the (162), #lignin (112), and (91), wood (35), doi (32), from (31), paper (25), plant (22), are (20), edit (18), degradation (17), pmid (17), for (17), with (14), been (14), retrieved (13), cell (13), peroxidases (13), lignins (12), bibcode (12), also (11), acid (11), alcohol (11), have (11), which (11), this (10), chemistry (10), 978 (10), isbn (10), 1016 (10), original (10), enzymes (10), its (10), most (10), plants (9), pulp (9), 2001 (9), pyrolysis (9), used (9), bacteria (9), water (9), may (8), cellulose (8), structural (8), formation (8), john (8), archived (8), not (8), that (8), has (8), can (8), some (8), wikipedia (7), non (7), polymers (7), other (7), timber (7), products (7), biomass (7), kraft (7), biodegradation (7), fungal (7), issn (7), pdf (7), compounds (7), organic (7), encyclopedia (7), composition (7), fungi (7), main (7), but (7), phenolic (7), using (6), was (6), sulfite (6), process (6), structure (6), wiley (6), biosynthesis (6), journal (6), presence (6), s2cid (6), production (6), 2016 (6), bacterial (6), rot (6), 2007 (6), wall (6), these (6), laccases (6), function (6), page (5), see (5), hemicellulose (5), log (5), chemicals (5), history (5), monolignols (5), links (5), ralph (5), nmr (5), vane (5), decay (5), characterization (5), their (5), 2018 (5), white (5), 1002 (5), syringyl (5), article (5), only (5), chemical (5), lignols (5), more (5), many (5), important (5), derived (5), components (5), radical (5), coniferyl (5), contents (4), search (4), about (4), commons (4), list (4), all (4), papermaking (4), international (4), tar (4), derivatives (4), cross (4), industry (4), environmental (4), free (4), types (4), reactions (4), 2005 (4), hydroxide (4), 1021 (4), analytical (4), pmc (4), 108 (4), first (4), microbial (4), dissolved (4), matter (4), analysis (4), polymer (4), based (4), species (4), technology (4), well (4), lignol (4), woody (4), material (4), solution (4), red (4), soluble (4), form (4), such (4), described (4), peroxidase (4), oxidize (4), both (4), polymerisation (4), walls (4), vascular (4), hide (4), move (4), sidebar (4), toggle (3), view (3), contact (3), inc (3), articles (3), 2023 (3), different (3), phenylpropanoids (3), fiber (3), lumber (3), building (3), smoke (3), ethanol (3), fiberboard (3), board (3), straw (3), pulping (3), thermal (3), tissue (3), bark (3), lignans (3), classes (3), new (3), state (3), tmah (3), thermochemolysis (3), ibiod (3), biodeterioration (3), during (3), growth (3), tetramethylammonium (3), food (3), applied (3), tissues (3), 7037 (3), 1974 (3), flavor (3), precursors (3), 2024 (3), peter (3), 2003 (3), phenols (3), 1983 (3), 221 (3), involved (3), molecular (3), structures (3), current (3), xylem (3), 14356007 (3), ullmann (3), industrial (3), step (3), angiosperms (3), sinapyl (3), mass (3), applications (3), quantitation (3), type (3), highly (3), oxidative (3), studied (3), klason (3), range (3), characteristic (3), source (3), redox (3), especially (3), where (3), ligninolytic (3), activity (3), even (3), three (3), than (3), guaiacyl (3), present (3), one (3), biological (3), precursor (3), less (3), removed (3), delignification (3), sulfide (3), related (3), support (3), thus (3), between (3), hydroxyphenylpropenol (3), sometimes (3), called (3), tools (3), languages (2), table (2), developers (2), conduct (2), privacy (2), policy (2), under (2), terms (2), site (2), wikimedia (2), use (2), last (2), edited (2), categories (2), cs1 (2), maint (2), multiple (2), names (2), authors (2), unsourced (2), statements (2), short (2), description (2), wikidata (2), japan (2), united (2), states (2), control (2), forestry (2), category (2), recycling (2), reclaimed (2), forest (2), engineered (2), bamboo (2), dry (2), distillation (2), wooden (2), sawdust (2), ties (2), oil (2), black (2), gas (2), cellulosic (2), birch (2), pulpwood (2), paperboard (2), corrugated (2), cardboard (2), fuel (2), charcoal (2), oriented (2), strand (2), joist (2), laminated (2), truss (2), beam (2), uses (2), mill (2), indonesia (2), india (2), canada (2), impact (2), strength (2), units (2), materials (2), parchment (2), seed (2), laid (2), hemp (2), francis (2), timothy (2), palm (2), leaf (2), acids (2), external (2), occurrence (2), ludwig (2), sons (2), york (2), 1971 (2), sarkanen (2), eds (2), further (2), reading (2), 2010 (2), advances (2), solid (2), off (2), line (2), 004 (2), wheat (2), mushroom (2), agricultural (2), hedges (2), oxidation (2), 0016 (2), february (2), cupric (2), oxide (2), glasser (2), simulation (2), model (2), softwood (2), 1995 (2), 1277 (2), november (2), research (2), 2020 (2), detection (2), insoluble (2), symposium (2), vol (2), 105816 (2), symbionts (2), shipworms (2), 2015 (2), 405940 (2), marine (2), hernes (2), photochemical (2), brian (2), robert (2), quality (2), 2017 (2), microbiology (2), evolution (2), phenolics (2), enzyme (2), phanerochaete (2), chrysosporium (2), 4611 (2), science (2), 661 (2), gonzalo (2), 011 (2), biotechnology (2), academic (2), lentinula (2), edodes (2), polysaccharide (2), resistance (2), cellular (2), 216 (2), what (2), link (2), cite (2), weinheim (2), germany (2), vch (2), 2011 (2), july (2), king (2), 2009 (2), role (2), 471 (2), biology (2), reveals (2), bio (2), 2021 (2), volume (2), monolignol (2), spectrometry (2), modeling (2), aspen (2), candolle (2), 1813 (2), kirk (2), othmer (2), references (2), spectroscopy (2), owing (2), substance (2), ratio (2), vanillyl (2), therefore (2), trace (2), aquatic (2), systems (2), ratios (2), information (2), degraded (2), reaction (2), shown (2), test (2), groups (2), digested (2), although (2), breakdown (2), two (2), guaiacol (2), smoked (2), cooking (2), methoxy (2), sub (2), like (2), via (2), several (2), including (2), community (2), mineral (2), lack (2), degrade (2), terrestrial (2), dyps (2), versatile (2), dyp (2), found (2), contrast (2), intracellular (2), secreted (2), heme (2), lignocellulose (2), whereas (2), manganese (2), dye (2), wide (2), general (2), substrates (2), varies (2), example (2), aryl (2), because (2), linked (2), coupling (2), low (2), radicals (2), catalysed (2), lignan (2), through (2), glucose (2), after (2), investigated (2), proposed (2), lignosulfonates (2), they (2), aqueous (2), sodium (2), making (2), mainly (2), cells (2), polysaccharides (2), plays (2), crosslinking (2), hydrophobic (2), citation (2), needed (2), amounts (2), monomers (2), common (2), paracoumaryl (2), heterogeneous (2), degree (2), according (2), carbon (2), algae (2), earth (2), appearance (2), upload (2), file (2), changes (2), read (2), norsk (2), bahasa (2), create (2), account (2), donate (2), menu (2), add, topic, mobile, cookie, statement, statistics, code, legal, safety, contacts, disclaimers, text, available, additional, apply, you, agree, registered, trademark, profit, organization, foundation, creative, attribution, sharealike, license, rendered, parsoid, september, 2026, utc, hidden, october, dietary, https, org, index, php, title, oldid, 1375869160, yale, lux, israel, latvia, czech, republic, bnf, data, france, national, gnd, authority, databases, wikiproject, yakisugi, woodworking, processing, preservation, drying, natural, mulch, woods, green, destructive, certified, masts, framing, tanbark, split, rail, fence, brandy, potash, dugout, canoe, clapboard, billet, bavin, axe, historical, woodchips, wool, flour, tall, ramial, chipped, liquor, barkdust, tannin, sandalwood, pitch, pine, pyroligneous, methanol, lye, liquid, dyes, nano, rayon, fibers, pellet, firewood, firelog, biochar, fuelwood, plastic, composite, insulated, panel, plywood, particle, mdf, masonite, hardboard, parallel, lvl, veneer, glued, utility, pole, treenail, stud, sill, siding, shingle, railroad, rafter, purlin, post, plate, plank, panelling, molding, house, cabin, lath, flooring, flitch, cruck, cls, bressummer, batten, money, watercolor, clothing, papier, mâché, blueprint, europe, soda, organosolv, chlorine, bleaching, deinking, hollander, beater, conical, refiner, calender, machine, manufacture, wet, quantity, surface, sizes, grammage, density, specifications, crop, kaolinite, china, clay, writing, wallpaper, transfer, tracing, security, graph, genkō, yōshi, ruled, rolling, origami, newsprint, inkjet, filteration, electrical, insulation, correction, carbonless, copy, cartridge, display, construction, butcher, bond, blotting, bible, wax, rosin, photographic, asphalt, coated, wove, wasli, toilet, towel, onionskin, ingres, glassine, crêpe, bristol, cardstock, blue, air, acidic, stone, xuan, mummy, rag, pith, rice, washi, samarkand, saa, hanji, daluang, mulberry, lokta, dung, cotton, manila, banana, tsien, tsuen, hsuin, dard, hunter, thomas, carter, barrett, scholars, charles, fenerty, friedrich, gottlob, keller, matthias, koops, damjing, cai, lun, vellum, papyrus, tapa, amate, barkcloth, slips, ancestors, engineering, rhododendrin, examples, suberins, stilbenoids, allylbenzenes, flavonoids, chalcones, coumarins, cinnamaldehydes, furanochromones, chromones, hydroxycinnamic, tecnaro, website, freudenberg, nash, 1968, berlin, springer, verlag, constitution, landucci, larry, boca, raton, taylor, 244, 57444, 486, 137, cultivated, apricot, ascomycete, 185, 2004, 175, hypocrea, sulphurea, prunus, armeniaca, oyster, 2716, 11409955, jf001409a, 2709, pleurotus, ostreatus, effect, agaricus, bisporus, s0165, 2370, 00156, 2001jaap, 69v, mann, dale, 1979, 1807, 90028, 1979gecoa, 1803h, 1803, geochimica, cosmochimica, acta, ertel, 1982, capillary, chromatography, 178, 0003, 2700, ac00239a007, 174, wolfgang, heidemarie, computer, simrel, 95157574, 1515, hfsg, holzforschung, lange, lapierre, sandermann, 1287, 12228544, 157483, 1104, physiology, elicitor, induced, spruce, stress, similarity, early, developmental, harkin, 1966, service, note, fpl, 0148, 2012, tappi, 222, wittkowski, reiner, ruther, joachim, drinda, heike, rafiei, taghanaki, foroozan, 1992, acs, series, 490, 243, 8412, 1346, 232, goodell, barry, chambers, james, ward, doyle, murphy, cecelia, eileen, mancilio, lucca, bonjy, kikuti, perez, gonzalez, gabriel, shipway, reuben, 2024ibibi, 19205816g, 192, report, digestive, system, boring, mollusks, dittmar, thorsten, reasons, behind, long, term, stability, 388, b978, 00007, 369, biogeochemistry, researchgate, persistence, soil, ecosystem, property, 3291, 1029, 2002jc001421, 2003jgrc, 3291h, geophysical, implications, fate, terrigenous, environments, pellerin, saraceno, johnfranco, spencer, bergamaschi, leachate, alters, trihalomethane, 954, 20400590, 0047, 2425, 2134, jeq2009, 0487, 2010jenvq, 946p, 946, cerisy, tristan, 28363966, 5440714, 1128, aem, 00289, 2017apenm, 83e, 289c, fermenting, bacterium, resist, tien, degrading, hymenomycete, burds, 8767248, 17787736, 1126, 1983sci, 661t, colpa, dana, habib, mohamed, fraaije, marco, 119, 27544286, 11370, 88943b84, 8228, 4612, 8315, daac2b3b31ae, hdl, jbiotec, 110, 236, sariaslani, sima, 2013, oxford, 841913543, oclc, 407679, gadd, geoffrey, 2006, fungus, loss, unmasking, suberin, 2006ibibi, 14v, oak, quercus, alba, shiitake, approach, 956, 12568554, jf020932h, 947, davin, lewis, primary, dirigent, sites, 415, 16023847, copbio, 407, opinion, samuels, rensing, douglas, mansfield, dharmawardhana, ellis, 2002, machinery, differentiation, secondary, pinus, contorta, var, latifolia, 20529001, 12430016, 1007, s00425, 002, 0884, 2002plant, 72a, planta, importance, abengoa, folkedahl, bruce, barbara, tokay, 2000, 527, 30673, a04_099, book, ragnar, henriksson, lindström, wimby, blechschmidt, heinemann, 2014, a18_545, pub4, higson, smith, nnfcc, renewable, factsheet, bhuiyan, nazmul, selvaraj, gopalan, wei, yangdou, 159, 19649200, 2637510, 1559, 2316, 4161, psb, 7688, 2009plsib, 158b, 158, signaling, behavior, lignification, defense, wardrop, 1969, 240, 1071, bt9690229, 229, aust, bot, eryngium, esau, katharine, 1977, 24520, anatomy, arms, karen, camp, pamela, saunders, college, pub, 050003, chabannes, 282, 11722770, 1046, 1365, 313x, 01159, 271, transgenic, tobacco, differential, individual, transformations, spatial, patterns, deposition, subcellular, levels, situ, isikgor, furkan, becer, remzi, 4559, 1759, 9954, 1039, c5py00263j, 1602, 01684, arxiv, 4497, lignocellulosic, sustainable, platform, intersci, 1003, 11423146, s0031, 9422, 00109, 2001pchem, 993r, 993, phytochemistry, elucidation, cad, comt, deficient, kuroda, ozawa, ueno, april, sago, metroxylon, sagu, 27962271, 11308334, jf001126i, 1840, agric, chem, institute, dialogue, newsletters, number, properties, glossary, nomenclature, laigeng, cheng, xiao, fei, leshkevich, jacqueline, umezawa, toshiaki, harding, scott, chiang, vincent, 1586, 11449052, 139549, 1105, tpc, 010111, 1567, regulated, novel, gene, encoding, dehydrogenase, letourneau, dane, volmer, dietrich, 188, 236200196, 34293221, 0277, mas, 21716, 144, reviews, methods, advanced, review, hsiang, hui, solomon, eitan, avni, coughlin, fall, mathematical, phenomena, washington, referenced, specified, martone, estevez, ruel, denny, somerville, jan, 17409200, 19167225, 0960, 9822, cub, 2008, 031, 2009cbio, 169m, 169, discovery, seaweed, convergent, architecture, britannica, boerjan, baucher, june, 549, 14503002, 1146, annurev, arplant, 031902, 134938, 519, annu, rev, biol, sjöström, 1993, 647480, press, fundamentals, 417, paris, deterville, theorie, elementaire, botanique, exposition, des, principes, classification, naturelle, art, decrire, etudier, les, vegetaux, lebo, stuart, gargulak, jerry, mcnally, 23896, 0471238961, 12090714120914, a01, pub2, saake, bodo, lehnen, 3527306732, a15_305, pub3, coal, carboniferous, period, models, examined, complexity, spectra, poorly, resolved, challenging, break, down, vacuum, high, temperature, characterize, cinnamyl, variable, sources, angiosperm, gymnosperm, carboxylic, aldehyde, forms, reveal, diagenetic, higher, indicating, increases, value, indicate, cleavage, occurred, alkyl, side, chain, soft, technique, computational, thioglycolysis, hydrochloric, wiesner, brilliant, color, develops, coniferaldehyde, phloroglucinol, conventional, method, standardized, procedures, thermally, residue, termed, asl, quantified, intensity, carbohydrate, analyzed, liquors, there, sugar, furfural, hydroxymethylfurfural, ultraviolet, yields, ones, substituted, those, fire, impart, aroma, taste, methyl, dimethylphenol, produced, smokehouse, ham, barbecue, foods, hardwood, syringol, combustion, ingests, organ, cecum, typhlosole, alteromonas, group, environment, either, biotically, abiotically, alteration, oftentimes, latter, assists, former, addition, absence, light, factors, affect, associations, biodegradability, employed, aliphatic, furans, solubilized, inhibit, yet, quite, extensive, lakes, rivers, streams, inputs, enter, waterways, extensively, though, 1930, characterized, express, any, four, litter, others, ability, involves, facilitate, aspect, accessory, produce, required, ceriporiopsis, subvermispora, include, copper, decolorizing, exhibit, catalytic, substrate, unknown, synthetic, mediators, vivo, decolourizing, proteins, dna, resists, immune, base, catalyzed, hydrolysis, degradability, susceptible, fewer, bonds, lower, potential, minimizes, accessibility, leading, reduced, digestibility, steric, hindrance, known, whether, participates, weight, oxidants, might, catalyses, often, said, undergo, uncatalyzed, alternative, theory, invokes, unspecified, laccase, initial, stages, byoxidative, oxidases, begins, synthesis, shared, pathway, attached, renders, them, once, transported, commences, much, understood, century, study, anabolism, apoplast, membrane, toxic, phenylpropanoid, phenylalanine, amino, glycosylated, cytosol, given, prevalent, biopolymer, feedstock, biofuel, sequestrants, lignosulfonate, concrete, superplasticizers, reducers, treatment, emulsion, stabilizers, humectants, dispersants, achieved, chips, various, dominant, way, usually, burned, power, accurately, depolymerizes, odoriferous, salts, delignify, cogenerates, retains, consequently, brownish, strong, product, organosulfur, dimethyl, hydrosulfide, heavily, focused, removal, roughly, remainder, being, component, lesser, amount, fraction, recovered, mills, yield, blankenstein, finally, confers, disease, accumulating, pathogen, infiltration, accessible, conferring, mechanical, extension, whole, commonly, noted, strengthening, composed, lignified, fibres, sclerenchyma, covalently, crucial, part, conducting, nutrients, stems, obstacle, absorption, makes, possible, efficiently, supporting, idea, restricted, transport, bryophytes, permeable, hydrophilic, fills, spaces, sclereid, vessel, elements, tracheids, pectin, grasses, mostly, while, palms, contain, small, incomplete, modified, prominent, exceed, 000, rich, subunits, difficult, measure, since, depending, means, isolation, aromatic, masses, relative, vary, typically, classified, gives, rise, upon, converted, gymnosperms, collection, handful, heterogeneity, arises, diversity, phenylpropene, dimethoxy, hydroxyphenyl, crosslink, sample, hydrogen, ash, oxygen, difference, corresponding, approximately, formula, suggest, ancestor, pre, adapted, synthesize, finding, suggests, alga, supports, joints, segments, calcified, calliarthron, mentioned, swiss, botanist, who, fibrous, tasteless, weak, alkaline, solutions, named, lignine, latin, word, meaning, abundant, exceeded, constitutes, fossil, chitin, lignum, precipitated, class, complex, key, particularly, lend, rigidity, easily, chemically, made, linking, idealized, phytoestrogen, item, projects, printable, version, download, print, export, switch, legacy, parser, get, shortened, url, permanent, here, actions, english, talk, tiếng, việt, oʻzbekcha, ўзбекча, українська, türkçe, ไทย, svenska, sunda, српски, srpski, slovenščina, slovenčina, srpskohrvatski, српскохрватски, русский, română, português, polski, bokmål, nynorsk, nederlands, melayu, मराठी, മലയാളം, latviešu, lietuvių, 한국어, қазақша, ქართული, jawa, 日本語, italiano, íslenska, ido, հայերեն, magyar, hrvatski, עברית, galego, français, suomi, فارسی, euskara, eesti, español, esperanto, ελληνικά, deutsch, dansk, čeština, català, bosanski, български, беларуская, تۆرکجه, العربية, subsection, top, personal, special, pages, recent, portal, learn, help, contribute, random, events, navigation, jump, content,

Text of the page (random words):
ch to legacy parser print export download as pdf printable version in other projects wikimedia commons wikidata item appearance move to sidebar hide from wikipedia the free encyclopedia structural phenolic polymer in plant cell walls this article is about the wood polymer for the phytoestrogen see lignan idealized structure of lignin from a softwood lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants 1 lignins are particularly important in the formation of cell walls especially in wood and bark because they lend rigidity and do not rot easily chemically lignins are polymers made by the cross linking of phenolic precursors 2 history edit lignin was first mentioned in 1813 by the swiss botanist a p de candolle who described it as a fibrous tasteless material insoluble in water and alcohol but soluble in weak alkaline solutions and which can be precipitated from solution using acid 3 he named the substance lignine which is derived from the latin word lignum 4 meaning wood it is one of the most abundant organic polymers on earth exceeded only by cellulose and chitin lignin constitutes 30 of terrestrial non fossil organic carbon 5 on earth and 20 to 35 of the dry mass of wood 6 lignin is present in red algae which suggest that the common ancestor of plants and red algae may have been pre adapted to synthesize lignin this finding also suggests that the original function of lignin may have been structural as it plays this role in the red alga calliarthron where it supports joints between calcified segments 7 composition and structure edit the composition of lignin varies from species to species an example of composition from an aspen 8 sample is 63 4 carbon 5 9 hydrogen 0 7 ash mineral components and 30 oxygen by difference 9 corresponding approximately to the formula c 31 h 34 o 11 n lignin is a collection of highly heterogeneous polymers derived from a handful of precursor lignols heterogeneity arises from the diversity and degree of crosslinking between these lignols the lignols that crosslink are of three main types all derived from phenylpropene coniferyl alcohol 3 methoxy 4 hydroxyphenylpropenol its radical g is sometimes called guaiacyl sinapyl alcohol 3 5 dimethoxy 4 hydroxyphenylpropenol its radical s is sometimes called syringyl and paracoumaryl alcohol 4 hydroxyphenylpropenol its radical h is sometimes called 4 hydroxyphenyl citation needed the relative amounts of the precursor monomers lignols or monolignols vary according to the plant source 5 lignins are typically classified according to their syringyl guaiacyl s g ratio lignin from gymnosperms is derived from the coniferyl alcohol which gives rise to g upon pyrolysis in angiosperms some of the coniferyl alcohol is converted to s thus lignin in angiosperms has both g and s components 10 11 lignin s molecular masses exceed 10 000 u it is hydrophobic as it is rich in aromatic subunits the degree of polymerisation is difficult to measure since the material is heterogeneous different types of lignin have been described depending on the means of isolation 12 the three common monolignols paracoumaryl alcohol h coniferyl alcohol g sinapyl alcohol s many grasses have mostly g while some palms have mainly s 13 all lignins contain small amounts of incomplete or modified monolignols and other monomers are prominent in non woody plants 14 biological function edit lignin fills the spaces in the cell wall between cellulose hemicellulose and pectin components especially in vascular and support tissues xylem tracheids vessel elements and sclereid cells citation needed lignin plays a crucial part in conducting water and aqueous nutrients in plant stems the polysaccharide components of plant cell walls are highly hydrophilic and thus permeable to water whereas lignin is more hydrophobic the crosslinking of polysaccharides by lignin is an obstacle for water absorption to the cell wall thus lignin makes it possible for the plant s vascular tissue to conduct water efficiently 15 lignin is present in all vascular plants 16 but not in bryophytes supporting the idea that the original function of lignin was restricted to water transport it is covalently linked to hemicellulose and therefore cross links different plant polysaccharides conferring mechanical strength to the cell wall and by extension the plant as a whole 17 its most commonly noted function is the support through strengthening of wood mainly composed of xylem cells and lignified sclerenchyma fibres in vascular plants 18 19 20 finally lignin also confers disease resistance by accumulating at the site of pathogen infiltration making the plant cell less accessible to cell wall degradation 21 delignification edit in pulp mills like this one in blankenstein germany using the kraft or the sulfite process lignin is removed from lignocellulose to yield pulp for papermaking the pulp and paper industry is heavily focused on the removal of lignin from woody and some related plants roughly 30 of wood is lignin the remainder being cellulose the main component of paper and a lesser amount of hemicellulose only a fraction of the lignin recovered in paper making is used a wide range of low volume applications have been proposed where the form but not the quality is important 22 delignification is achieved by cooking wood chips in a solution of various chemicals in the kraft process which is the dominant technology an aqueous solution of sodium sulfide and sodium hydroxide is used lignin removed in this way is usually burned to power the paper mill the sulfide or more accurately the hydrosulfide sh depolymerizes the lignin a characteristic of the kraft process is the formation of dimethyl sulfide and related odoriferous organosulfur compounds in sulfite pulping sulfite salts are used to delignify this technology cogenerates lignosulfonates paper from the kraft process retains some lignin and is consequently brownish less strong than the kraft product is sulfite paper which is white 23 many applications have been proposed for the lignosulfonates 24 they are used as dispersants humectants emulsion stabilizers and sequestrants water treatment 25 lignosulfonate has been investigated as a water reducers or superplasticizers for concrete given that it is the most prevalent biopolymer after cellulose lignin has been investigated as a feedstock for biofuel production 26 27 biosynthesis edit lignin biosynthesis begins in the cytosol with the synthesis of glycosylated monolignols from the amino acid phenylalanine these first reactions are shared with the phenylpropanoid pathway the attached glucose renders them water soluble and less toxic once transported through the cell membrane to the apoplast the glucose is removed and the polymerisation commences 28 much about its anabolism is not understood even after more than a century of study 5 initial stages in the formation of lignin from coniferyl alcohol the reaction is catalysed byoxidative enzymes peroxidases or oxidases lignan is a precursor to lignin the polymerisation step that is a radical radical coupling is catalysed by oxidative enzymes both peroxidase and laccase enzymes are present in the plant cell walls and it is not known whether one or both of these groups participates in the polymerisation low molecular weight oxidants might also be involved the oxidative enzyme catalyses the formation of monolignol radicals these radicals are often said to undergo uncatalyzed coupling to form the lignin polymer 29 an alternative theory invokes an unspecified biological control 1 biodegradation edit in contrast to other bio polymers e g proteins dna and even cellulose lignin resists degradation it is immune to both acid and base catalyzed hydrolysis the degradability varies with species and plant tissue type for example syringyl s lignin is more susceptible to degradation by fungal decay as it has fewer aryl aryl bonds and a lower redox potential than guaiacyl units 30 31 because it is cross linked with the other cell wall components lignin minimizes the accessibility of cellulose and hemicellulose to microbial enzymes e g steric hindrance leading to a reduced digestibility of biomass 15 some ligninolytic enzymes include heme peroxidases such as lignin peroxidases manganese peroxidases versatile peroxidases and dye decolourizing peroxidases as well as copper based laccases lignin peroxidases oxidize non phenolic lignin whereas manganese peroxidases only oxidize the phenolic structures dye decolorizing peroxidases or dyps exhibit catalytic activity on a wide range of lignin model compounds but their in vivo substrate is unknown in general laccases oxidize phenolic substrates but some fungal laccases have been shown to oxidize non phenolic substrates in the presence of synthetic redox mediators 32 33 lignin degradation by fungi edit well studied ligninolytic enzymes are found in phanerochaete chrysosporium 34 and other white rot fungi some white rot fungi such as ceriporiopsis subvermispora can degrade the lignin in lignocellulose but others lack this ability most fungal lignin degradation involves secreted peroxidases many fungal laccases are also secreted which facilitate degradation of phenolic lignin derived compounds although several intracellular fungal laccases have also been described an important aspect of fungal lignin degradation is the activity of accessory enzymes to produce the h 2 o 2 required for the function of lignin peroxidase and other heme peroxidases 32 lignin degradation by bacteria edit bacteria lack most of the enzymes employed by fungi to degrade lignin and lignin derivatives aliphatic acids furans and solubilized phenolics inhibit the growth of bacteria 35 yet bacterial degradation can be quite extensive 36 especially in aquatic systems such as lakes rivers and streams where inputs of terrestrial material e g leaf litter can enter waterways the ligninolytic activity of bacteria has not been studied extensively even though it was first described in 1930 many bacterial dyps have been characterized bacteria do not express any of the plant type peroxidases lignin peroxidase mn peroxidase or versatile peroxidases but three of the four classes of dyp are only found in bacteria in contrast to fungi most bacterial enzymes involved in lignin degradation are intracellular including two classes of dyp and most bacterial laccases 33 in the environment lignin can be degraded either biotically via bacteria or abiotically via photochemical alteration and oftentimes the latter assists in the former 37 in addition to the presence or absence of light several of environmental factors affect the biodegradability of lignin including bacterial community composition mineral associations and redox state 38 39 in shipworms the lignin it ingests is digested by alteromonas like sub group bacteria symbionts in the typhlosole sub organ of its cecum 40 pyrolysis edit pyrolysis of lignin during the combustion of wood or charcoal production yields a range of products of which the most characteristic ones are methoxy substituted phenols of those the most important are guaiacol and syringol and their derivatives their presence can be used to trace a smoke source to a wood fire in cooking lignin in the form of hardwood is an important source of these two compounds which impart the characteristic aroma and taste to smoked foods such as barbecue the main flavor compounds of smoked ham are guaiacol and its 4 5 and 6 methyl derivatives as well as 2 6 dimethylphenol these compounds are produced by thermal breakdown of lignin in the wood used in the smokehouse 41 chemical analysis edit main article lignin characterization the conventional method for lignin quantitation in the pulp industry is the klason lignin and acid soluble lignin test which is standardized procedures the cellulose is digested thermally in the presence of acid the residue is termed klason lignin acid soluble lignin asl is quantified by the intensity of its ultraviolet spectroscopy the carbohydrate composition may be also analyzed from the klason liquors although there may be sugar breakdown products furfural and 5 hydroxymethylfurfural 42 a solution of hydrochloric acid and phloroglucinol is used for the detection of lignin wiesner test a brilliant red color develops owing to the presence of coniferaldehyde groups in the lignin 43 thioglycolysis is an analytical technique for lignin quantitation 44 lignin structure can also be studied by computational simulation 45 thermochemolysis chemical break down of a substance under vacuum and at high temperature with tetramethylammonium hydroxide tmah or cupric oxide 46 has also been used to characterize lignins the ratio of syringyl lignol s to vanillyl lignol v and cinnamyl lignol c to vanillyl lignol v is variable based on plant type and can therefore be used to trace plant sources in aquatic systems woody vs non woody and angiosperm vs gymnosperm 47 ratios of carboxylic acid ad to aldehyde al forms of the lignols ad al reveal diagenetic information with higher ratios indicating a more highly degraded material 30 31 increases in the ad al value indicate an oxidative cleavage reaction has occurred on the alkyl lignin side chain which has been shown to be a step in the decay of wood by many white rot and some soft rot fungi 30 31 48 49 50 lignin and its models have been well examined by 1 h and 13 c nmr spectroscopy owing to the structural complexity of lignins the spectra are poorly resolved and quantitation is challenging 51 see also edit carboniferous period coal formation references edit 1 2 saake bodo lehnen ralph 2007 lignin ullmann s encyclopedia of industrial chemistry weinheim wiley vch doi 10 1002 14356007 a15_305 pub3 isbn 978 3527306732 lebo stuart e jr gargulak jerry d mcnally timothy j 2001 lignin kirk othmer encyclopedia of chemical technology kirk othmer encyclopedia of chemical technology john wiley sons inc doi 10 1002 0471238961 12090714120914 a01 pub2 isbn 978 0 471 23896 6 archived from the original on 2020 04 10 retrieved 2007 10 14 de candolle m a p 1813 theorie elementaire de la botanique ou exposition des principes de la classification naturelle et de l art de decrire et d etudier les vegetaux paris deterville see p 417 e sjöström 1993 wood chemistry fundamentals and applications academic press isbn 978 0 12 647480 0 1 2 3 w boerjan j ralph m baucher june 2003 lignin biosynthesis annu rev plant biol 54 1 519 549 doi 10 1146 annurev arplant 54 031902 134938 pmid 14503002 lignin encyclopedia britannica 2023 10 05 retrieved 2023 10 26 martone pt estevez jm lu f ruel k denny mw somerville c ralph j jan 2009 discovery of lignin in seaweed reveals convergent evolution of cell wall architecture current biology 19 2 169 75 bibcode 2009cbio 19 169m doi 10 1016 j cub 2008 12 031 issn 0960 9822 pmid 19167225 s2cid 17409200 in the referenced article the species of aspen is not specified only that it was from canada hsiang...