Tannin activity lignins

Tannins are a heterogeneons gronp of phenolic componnds that precipitate proteins. Both tannins and lignins play an important role in the decomposition of labile plant constitnents by com-plexing with proteins, exhibiting antibiotic activity, and forming an association with cellnlose and hemicellulose (Boultin and Boon, 1991). 

Many contaminants in wastewater today, such as dissolved dyestuffs, lignins, detergents, proteins, fatty acids, tannins, and so on, possess surface-active properties that decrease surface tension and oxygen transfer rate, but increase the demand for dissolved oxygen. Particularly, the sharp reduction in surface tension of water by these pollutants seems to be a basic cause of increasing the susceptibility of aquatic life to the surfactant poison. 

UF, urea-formaldehyde resin MUF, melamine fortified UF resin MF/MUF, melamine and melamine-urea resins (MF resins are only used mixed/coreacted with UF resins MUPF, melamine-urea-phenol-formaldehyde resin PF/PUF, phenol and phenol-urea-formaldehyde resin (P)RF, resoreinol-(phenol-)formaldehyde resin PMDI, polymeric methylenediisocyanate PVAc, polyvinylacetate adhesive old nat.adhesives, old (historic) natural adhesives (e.g., starch, glutin, casein adhesives) nat.adhesives, natural adhesives (e.g., tannins, lignins, carbohydrates) inorg.adhesives, inorganic adhesives (e.g., cement, gypsum) activation activation constituents of wood to function as adhesives (i.e., lignin). 

Phenolic compounds are widespread products of secondary metabolism of lichen, and antioxidant activity is most frequently associated with their presence. Lichen phenolics are mainly depsides, depsidones and dibenzofurans, whereas vascular plant phenolics include tannins, lignins and flavonoids. Orsellinic acid is the basic unit in the biosynthesis of hchen phenolics. Lichen phenols are generally secreted by the fungal partner and deposited as crystals on the surface of the ceU wall of the fungal hyphae. Lichen phenols are primarily acetate-polymalonate derived with the exception of pulvinic acid derivates which are synthesised via... 

The most noteworthy limitation to this approach is the complexity and multi-functionality that exist in these waste streams. For example, a bleached kraft pulp mill is estimated to produce greater than 400 compounds including tannins, resins, and lignin degradation products (5). However, as only a relatively small number of chemical transformations offer benefits to an end-user, i.e. polymerisation, selective oxidation or reduction, C-H bond activation, and carbon-halogen bond cleavage, the problem is simplified to some extent. 

Particleboards Wood particles, shives of flax flakes, saw dust, bagasse, hemp, kenaf, jute, cereal straw, coconut coir, corn and cotton stalks, rice husks, vetiver roots, and other fiber sources Urea, melamine, phenol formaldehyde resin, isocyanate, resorcinol, vinyl polyacetate resins and natural polymers, tannins, protein, casein, soybeans, modified starch, lignin activated by enzymatic system polylactic and polyhydroxyhutyric acid... 

---