Costs cellulose degradation

EC Ethyl cellulose Degradable, biocompatible, yproved by FDA for pharmaceutical yplication low cost... 

From an industrial perspective, the use of carbohydrate-active enzymes as cost effective, selective catalysts of biomass hydrolysis has been growing steadily over the last century (5). In particular, carbohydrases play key roles in the starch processing, animal feed, textile, and pulp and paper industries (5-7) (Table 1). The observation that enzymatic starch processing alone accounted for nearly 10% of the U.S. 1.4 billion enzyme market (1998 values) further underscores the importance of these catalysts (6). The use of (hemi)cellulose-degrading enzymes to saccharify biomass as a precursor to biofuels production and other bioreflnery purposes are of particular contemporary interest in the quest to reduce fossil fuel dependence (5,8,9). 

Various biomass sources as feedstock are a great opportunity and a major cost driver at the same time (Rude and Schirmer 2009). This refers mostly to the use of lignocellulosic biomass. In order to achieve economical and environmentally sustainable biofuel production, plant cellulose and hemiceUulose will have to be utilised more efficiently. This will require a better understanding of the cellulose-degrading multiprotein complex—the cellulosome (Kamm et al. 2011 Wackett 2008). 

As for the solid support, several polymer-supported amines were tested (Fig. 2). For either the pyrazole and isoxazole synthesis, the best results were given by aniline-functionalized cellulose, which has also the advantage of a relatively low cost. For the 2-aminopyrimidine library, polystyrene-based piperazine and piperidine gave products with a much higher purity compared with other secondary non-cyclic or primary amines, hi both cases, the resins could be reused for up to four times before degradation in their behavior was observed. This reusability could be further enhanced (up to 10 cycles for cellulose-based aniline) when the microwave-assisted protocols were used. 

At high concentrations, corrosion-resistant reactors and an effective acid recovery process are needed, raising the cost of the intermediate glucose. Dilute acid treatments minimize these problems, but a number of kinetic models indicate that the maximum conversion of cellulose to glucose under these conditions is 65 to 70 percent because subsequent degradation reactions of the glucose to HMF and lev-ulinic acid take place. The modem biorefinery is learning to exploit this reaction manifold, because these decomposition products can be manufactured as the primary product of polysaccharide hydrolysis (see below). 

Trimethylsilylcellulose has been prepared from cellulose and 1,1,1,3,3,3-hexamethyldisilazane in liquid ammonia in an autoclave.86 There were no by-product salts, no tedious purification, and no degradation of the polymer chain. Such a process might be run in an extruder. The cost of the reagent may be a drawback to widespread use. 

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