Fibers enzymes

Immobilization by chemical bonding gives strong, irreversible attachments to a solid support. The bonds are normally covalent but they can be electrostatic. Typical supports are functionalized glass and ceramic beads and fibers. Enzymes are sometimes cross-linked to form a gel. Occasionally, enz5anes can be flocculated while retaining catalytic activity. 

Felby C, Olesen PO, Hansen TT (1998) Laccase catalyzed bonding of wood fibers. Enzymes in fiber processing. ACS Symp Ser 687 88-98... 

Over time, the chronic acid load on our glands, organs, tissues, and blood can have serious health repercussions. To worsen the situation, acidic foods lack many of the vitamins, minerals, fiber, enzymes, and other nutritional components that help our bodies restore balance, which adds further strain to our already overwhelmed systems. We ll discuss which acidic foods to reduce or eliminate from your diet, as well as which ones are worth keeping, in chapter 4. 

Besides these conventional reactors with spherical immobilizates, urease has also been immobilized inside nylon tubing and pipette tips ( enzyme pipette , Sundaram and Jayonne, 1979), on nylon fibers ( enzyme brush , Raghavan et al., 1986), and on the surface of a magnetic stirrer (Guilbault and Starklov, 1975). The urease reaction was in each case carried out at optimal pH after removal of the immobilized enzyme NH3 was assayed electrochemically or photometrically according to Berthelot s method. 

Transmission electron microscopy Is also used to obtain Information about the shapes of purified viruses, fibers, enzymes, and other subcellular particles by using a technique, called metal shadowing. In which a thin layer of metal, such... 

Similar reactor configurations using flat membranes in place of hollow fibers have even been used with urease, uricase, glucose oxidase and creatinine kinase.49 An enzyme solution is, in this case, introduced into one of the membrane-separated chambers of a flat-membrane dialyzer. Operating the reactor at high feed flow rates leads to a reduction of mass transfer resistances, which can also be achieved using suitable turbulence promoters. The overall behavior of such systems appears to be similar to that of the hollow fiber enzyme reactors, except for an apparent higher efficiency.49... 

Kim SY, Zille A, Murkovic M et al (2007) Enzymatic polymerization on the surface of functionalized cellulose fibers. Enzyme Microb Technol 40 1782-1787... 

Enzyme degradation of leaf protein may occur during emshing and separation from the fiber. The amino acids produced by this enzyme action are soluble in the juice and may be lost unless all of the juice is recovered. 

In most cases, hoUow fibers are used as cylindrical membranes that permit selective exchange of materials across their waUs. However, they can also be used as containers to effect the controUed release of a specific material (2), or as reactors to chemically modify a permeate as it diffuses through a chemically activated hoUow-fiber waU, eg, loaded with immobilized enzyme (see Enzyme applications). 

In open fibers the fiber wall may be a permselective membrane, and uses include dialysis, ultrafiltration, reverse osmosis, Dorman exchange (dialysis), osmotic pumping, pervaporation, gaseous separation, and stream filtration. Alternatively, the fiber wall may act as a catalytic reactor and immobilization of catalyst and enzyme in the wall entity may occur. Loaded fibers are used as sorbents, and in ion exchange and controlled release. Special uses of hoUow fibers include tissue-culture growth, heat exchangers, and others. 

Neuropeptide Y. Neuropeptide Y [82785 5-3] (NPY) (255) is a 36-amiao acid peptide that is a member of a peptide family including peptide YY (PYY) [81858-94-8, 106338-42-5] (256) and pancreatic polypeptide (PPY) [59763-91-6] (257). In the periphery, NPY is present in most sympathetic nerve fibers, particulady around blood vessels and also in noradrenergic perivascular and selected parasympathetic nerves (66). Neurons containing NPY-like immunoreactivity ate abundant in the central nervous system, particulady in limbic stmctures. Coexistence with somatostatin and NADPH-diaphorase, an enzyme associated with NO synthesis, is common in the cortex and striatum. 

Films or membranes of silkworm silk have been produced by air-drying aqueous solutions prepared from the concentrated salts, followed by dialysis (11,28). The films, which are water soluble, generally contain silk in the silk I conformation with a significant content of random coil. Many different treatments have been used to modify these films to decrease their water solubiUty by converting silk I to silk II in a process found usehil for enzyme entrapment (28). Silk membranes have also been cast from fibroin solutions and characterized for permeation properties. Oxygen and water vapor transmission rates were dependent on the exposure conditions to methanol to faciUtate the conversion to silk II (29). Thin monolayer films have been formed from solubilized silkworm silk using Langmuir techniques to faciUtate stmctural characterization of the protein (30). ResolubiLized silkworm cocoon silk has been spun into fibers (31), as have recombinant silkworm silks (32). 

An important chemical finishing process for cotton fabrics is that of mercerization, which improves strength, luster, and dye receptivity. Mercerization iavolves brief exposure of the fabric under tension to concentrated (20—25 wt %) NaOH solution (14). In this treatment, the cotton fibers become more circular ia cross-section and smoother ia surface appearance, which iacreases their luster. At the molecular level, mercerization causes a decrease ia the degree of crystallinity and a transformation of the cellulose crystal form. These fine stmctural changes iacrease the moisture and dye absorption properties of the fiber. Biopolishing is a relatively new treatment of cotton fabrics, involving ceUulase enzymes, to produce special surface effects (15). 

Textile finishing includes various efforts to improve the properties of textile fabrics, whether for apparel, home, or other end uses. In particular, these processes are directed toward modifying either the fiber characteristics themselves or the gross textile end properties. Such modifications may be chemical or mechanical in nature. One modification that is not covered in this article relates to the dyeing of textiles and the dyestuffs employed for fibers however, areas that involve chemical finishing designed to modify the normal dye receptivity and the growing use of enzyme treatments are included. 

The dye is excited by light suppHed through the optical fiber (see Fiber optics), and its fluorescence monitored, also via the optical fiber. Because molecular oxygen, O2, quenches the fluorescence of the dyes employed, the iatensity of the fluorescence is related to the concentration of O2 at the surface of the optical fiber. Any glucose present ia the test solution reduces the local O2 concentration because of the immobilized enzyme resulting ia an iacrease ia fluorescence iatensity. This biosensor has a detection limit for glucose of approximately 100 ]lM , response times are on the order of a miaute. 

Historically, dietary fiber referred to iasoluble plant cell wall material, primarily polysaccharides, not digested by the endogenous enzymes of the human digestive tract. This definition has been extended to iaclude other nondigestible polysaccharides, from plants and other sources, that are iacorporated iato processed foods. Cellulose [9004-34-6] (qv) is fibrous however, lignin [9005-53-2] (qv) and many other polysaccharides ia food do not have fiberlike stmctures (see also Carbohydrates). 

Enzymatic stone-washing is performed either entirely without stones or sometimes by a combination of stones and enzymes. CeUulases are used to attack the surface of the cellulose fiber, but leave the interior intact. Denim garments are dyed with indigo blue, which stays on the surface of the yam. The ceUulase partiy hydrolyzes the surface of the fiber, and the indigo blue is partiy removed. Either neutral-type ceUulases acting at pH 6—8 or acid-type ceUulases acting at pH 4—5 are used for these processes. 

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