Cellulose deconstruction

However, further cellulose deconstruction is considerably more difficult after acid hydrolysis. Commercial processes for acid hydrolysis of cellulose were known in the early part of the twentieth century.434 The use of either low- or high-acid concentrations has disadvantages. 

Lignocellulosic biomass is a valuable and plentiful feedstock commodity and its high cellulose and hemicellulose content (about 80% of total) provides considerable potential for inexpensive sugars production. However, enzymatic deconstruction of these polysaccharides remains a costly prospect. Strides in cellulase cost reduction have been made, yet further improvements are needed to reach the goal of 0.10/gal of EtOH expected to enable this new industry. Strategies to reach this goal will combine reduction in the cost to produce the needed enzymes as well as efforts to increase enzyme efficiency (specific activity). As this work proceeds, the more easily attained achievements will be made first, and thus the overall difficulty increases with time. 

Under proper conditions, biomass deconstruction will generate streams of monomeric or oligomeric carbohydrates, with glucose and xylose (from cellulose/starch or hemicel-... 

Zhang Q, Jerome F (2013) Mechanocatalytic deconstruction of cellulose an emerging taitry into biorefinery. ChemSusChem 6(ll) 2042-2044... 

The classical endo-exo deconstruction model of pure cellulose is undergoing revision in light of the recent discovery of a family of copper-dependent polysaccharide mono-oxygenases from the GH61 family (Table 4.1) (Harris et al., 2010 Quinlan et al., 2011). These enzymes represent a novel mechanism to deconstruct cellulose in that they cleave cellulose oxidatively, unlike traditional acid/base catalyzed enzyme systems. Family GH61 enzymes can also provide powerful synergistic benefits to cocktails of traditional GH5, GH6, and GH7 enzyme mixtures (Harris et al., 2010). 

Dumesic and collaborators developed a process for the catalytic upgrading of levulinic acid to 5-nonanone, with the intermediate formation of y-valerolactone (Fig. 13.3). Levulinic acid can be obtained inexpensively and in high yields via acid hydrolysis of waste cellulosic materials. The process starts with the deconstruction of solid cellulose in an aqueous solution of sulfuric acid yielding an equimolar mixture of levulinic acid and formic acid. The formic... 

NMR spectroscopy is a well-established analytical technique in biofuel research. Over the past few decades, lignocellulosic biomass and its conversion to supplement or displace non-renewable feedstocks has attracted increasing interest. The application of solid-state NMR spectroscopy has long been seen as an important tool in the study of cellulose and lignocellulose structure, biosynthesis, and deconstruction, especially considering the limited number of effective solvent systems and the significance of plant cell wall three-dimensional microstructure and component interaction to conversion yield and rate profiles. The article by Foston reviews common and recent applications of solid-state NMR spectroscopy methods that provide insight into the structural and dynamic processes of cellulose that control bulk properties and biofuel conversion. 

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