Isolation of Lignin from Pulp

Springer Series in Wood Science Methods in Lignin Chemistry (Edited by S.Y. Lin and C.W. Dence) 

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Poliin J, Bezuch B (1978) Enzymic isolation of lignin from wood and pulps Wood Sci Technol 12 149-158... 

Similarly to the isolation of LCC from wood, isolation of LCC from pulps can be performed using enzymatic hydrolysis. These preparations are usually called enzymatic residual lignins [46-49]. However, similarly to CEL, they contain significant amounts of LCC linkages proven by two-dimensional nuclear magnetic resonance (2D NMR) methods and therefore can be considered as LCC preparations [48,50,51]. Ball milling is not needed for the isolation of LCC from most chemical pulps, and as a result mechanical degradation can be avoided. 

Production The most important sources of crude C. are cotton and bast plants flax, ramie, jute, hemp (at present still very small amounts) for the textile industry and wood for the paper and pulp industry, in smaller amounts from bagasse. The isolation of C. from wood needs a series of processes in order to separate C. from lignin and polyoses. 

The isolation of chemicals from Kraft lignin, the polymer by-product of the Kraft pulping process for paper production, is an established industrial process [219]. There have been several studies on alternative degradation processes such as hydro-genolysis [220], biodegradation with white-rot fungi [221], and chemical oxidation [121,122,222]. These processes can in principle be used with residual lignin obtained from vine shoots employed for paper pulp production. 

The first step to obtain nanocellulose by acid hydrolysis constitutes a number of processes, known as pulping and bleaching, that involves the isolation of fibers from the breakdown of cellulose-lignin-poUosis complex without the destruction of fibrils [22,23]. 

The significance of phenoxy anions is well recognized in the isolation of kraft and other water-insoluble technical lignins by acid precipitation. The ioniza tion of phenoHc hydroxyl groups coupled with the reduction of molecular size renders native lignin soluble in the aqueous pulping solution, thus enabling its separation from the polysaccharide components of wood. 

Holocellulose Cellulosic material obtainable from wood after removal of lignin. The term therefore means total carbohydrates (cellulose and hemicellulose) present in the wood (Refs 1 2) Ritter (Ref 3) succeded in isolating holocellulose from wood pulp by repeated chlori-nations, followed by extraction with alcohol containing 3% of monoethanolamine. The resulting product was white but changed color on standing... 

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