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Xylanase
Endo-1,4-β-xylanase (, systematic name 4-β-D-xylan xylanohydrolase) is any of a class of enzymes that degrade the linear polysaccharide xylan into xylose, thus breaking down hemicellulose, 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-organisms 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-free bleaching of wood pulp prior to the papermaking process, and the increased digestibility of silage (in this aspect, it is also used for fermentative composting). Apart from its use in the pulp and paper industry, xylanases are also used as food additives to poultry ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bleaching Of Wood Pulp
Bleaching of wood pulp is the chemical processing of wood pulp to lighten its color and whiten the pulp. The primary product of wood pulp is paper, for which whiteness (similar to, but distinct from brightness) is an important characteristic. These processes and chemistry are also applicable to the bleaching of non-wood pulps, such as those made from bamboo or kenaf. Paper brightness Brightness is the amount of incident light reflected from paper under specified conditions, usually reported as the percentage of light reflected, so a higher number means a brighter or whiter paper. In the US, the TAPPI T 452 or T 525 standards are used. The international community uses ISO standards. The table shows how the two systems rate high-brightness papers, but there is no simple way to convert between the two systems because the test methods are so different. The ISO rating is higher and can be over 100. This is because contemporary white paper incorporates fluorescent whiten ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 abundant polysaccharide on Earth, after cellulose and chitin. Composition Xylans are polysaccharides made up of β-1,4-linked xylose (a pentose sugar) residues with side branches of α-arabinofuranose and/or α-glucuronic acids. On the basis of substituted groups xylan can be categorized into three classes i) glucuronoxylan (GX) ii) neutral arabinoxylan (AX) and iii) glucuronoarabinoxylan (GAX). In some cases contribute to cross-linking of cellulose microfibrils and lignin through ferulic acid residues. Occurrence Plant cell structure Xylans play an important role in the integrity of the plant cell wall and increase cell wall recalcitrance to enzymatic digestion; thus, they help plants to defend against herbivores and pathogens (b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 agricultural, domestic or industrial Biodegradable waste, bio waste. Biofuels are mostly used for transportation, but can also be used for heating and electricity. Biofuels (and bioenergy, bio energy in general) are regarded as a renewable energy source. The use of biofuel has been subject to criticism regarding the "food vs fuel" debate, varied assessments of their Sustainable biofuel, sustainability, and ongoing deforestation and biodiversity loss as a result of biofuel production. In general, biofuels emit fewer greenhouse gas emissions when burned in an engine and are generally considered carbon-neutral fuels as the carbon emitted has been captured from the atmosphere by the crops used in production. However, life-cycle assessments of biofue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, mineral salts, oxidants and reductants, bleaching agents and emulsifiers. They are food additives combined with flour to improve baking functionality. Flour treatment agents are used to increase the speed of dough rising and to improve the strength and workability of the dough. Examples Examples of dough conditioners include ascorbic acid, distilled monoglycerides, citrate ester of monoglycerides, diglycerides, ammonium chloride, enzymes, diacetyl tartaric acid ester of monoglycerides or DATEM, potassium bromate, potassium iodate, calcium salts such as calcium iodate, L-cystine, L-cysteine HCl, glycerol monostearate, azodicarbonamide, sodium stearoyl lactylate, sucrose palmitate or other sucrose esters, polyoxyethylene sor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SpyCatcher
''Spycatcher: The Candid Autobiography of a Senior Intelligence Officer'' (1987) is a memoir written by Peter Wright, former MI5 officer and assistant director, and co-author Paul Greengrass. Wright drew on his experiences and research into the history of the British intelligence community. Published first in Australia, the book was banned in England (but not Scotland) due to its allegations about government policy and incidents. These efforts ensured the book's notoriety, and it earned considerable profit for Wright. In 2021 and 2023, the Cabinet Office was still blocking or redacting freedom of information requests for files on the ''Spycatcher'' affair despite the rule that documents should be released after 30 years. Information belonging to the security services is absolutely exempted from the Freedom of Information Act. Content In ''Spycatcher'', Wright says that one of his assignments was to unmask a Soviet mole in MI5, who he says was Roger Hollis, a former ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 introduced into a paper machine where it is shaped into a paper web and water is extracted through pressing and drying stages. Pressing involves removing water from the sheet by applying force. This process employs a specialized type of felt, distinct from traditional felt, to absorb the water. In contrast, hand-made paper uses a blotter sheet for this purpose. Drying involves eliminating water from the paper sheets through air or heat. Historically, this was achieved by hanging the sheets to dry, similar to laundry. In modern papermaking, various heated drying mechanisms are employed, with the steam-heated can dryer being the most prevalent on paper machines. History Papermaking as a craft is ancient, and for centuries it used various fibers, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaerobic Digestion
Anaerobic digestion is a sequence of processes by which microorganisms break down biodegradable material in the absence of oxygen. The process is used for industrial or domestic purposes to Waste management, manage waste or to produce fuels. Much of the Fermentation (biochemistry), fermentation used industrially to produce food and drink products, as well as home fermentation, uses anaerobic digestion. Anaerobic digestion occurs naturally in some soils and in lake and oceanic basin sediments, where it is usually referred to as "anaerobic activity". This is the source of Methane#Occurrence, marsh gas methane as discovered by Alessandro Volta in 1776. Anaerobic digestion comprises four stages: * Hydrolysis *Acidogenesis *Acetogenesis *Methanogenesis The digestion process begins with bacterial hydrolysis of the input materials. Insoluble organic polymers, such as carbohydrates, are broken down to soluble derivatives that become available for other bacteria. Acidogenesis, Acidogen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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'', ''ensiling'', or ''silaging''. The exact methods vary, depending on available technology, local tradition and prevailing climate. Silage is usually made from grass crops including maize, sorghum or other cereals, using the entire green plant (not just the grain). Specific terms may be used for silage made from particular crops: ''oatlage'' for oats, ''haylage'' for alfalfa (''haylage'' may also refer to high dry matter silage made from hay). History Using the same technique as the process for making sauerkraut, green fodder was preserved for animals in parts of Germany since the start of the 19th century. This gained the attention of French agriculturist Auguste Goffart of Sologne, near Orléans. He published a book in 1877 which describ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 molecules known as product (chemistry), products. Almost all metabolism, metabolic processes in the cell (biology), cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme, pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts include Ribozyme, catalytic RNA molecules, also called ribozymes. They are sometimes descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 paper survives as a specialized craft and a medium for paper art, artistic expression. In papermaking, a dilute suspension consisting mostly of separate cellulose fibres in water is drained through a sieve-like screen, so that a mat of randomly interwoven fibres is laid down. Water is further removed from this sheet by pressing, sometimes aided by suction or vacuum, or heating. Once dry, a generally flat, uniform and strong sheet of paper is achieved. Before the invention and current widespread adoption of automated machinery, all paper was made by hand, formed or laid one sheet at a time by specialized laborers. Even today those who make paper by hand use tools and technologies quite similar to those existing hundreds of years ago, as origin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidizing agent, oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the revised Electronegativity#Pauling electronegativity, Pauling scale, behind only oxygen and fluorine. Chlorine played an important role in the experiments conducted by medieval Alchemy, alchemists, which commonly involved the heating of chloride Salt (chemistry), salts like ammonium chloride (sal ammoniac) and sodium chloride (common salt), producing various chemical substances containing chlorine such as hydrogen chloride, mercury(II) chloride (corrosive sublimate), and . However, the nature of fre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Evolution of mammalian auditory ossicles, middle ear bones. These characteristics distinguish them from reptiles and birds, from which their ancestors Genetic divergence, diverged in the Carboniferous Period over 300 million years ago. Around 6,640 Neontology#Extant taxon, extant species of mammals have been described and divided into 27 Order (biology), orders. The study of mammals is called mammalogy. The largest orders of mammals, by number of species, are the rodents, bats, and eulipotyphlans (including hedgehogs, Mole (animal), moles and shrews). The next three are the primates (including humans, monkeys and lemurs), the Artiodactyl, even-toed ungulates (including pigs, camels, and whales), and the Carnivora (including Felidae, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
