Lignocellulosic residues

The next generation of biofuel processes should differ from the first in (a) utilizing the whole plant as a feedstock and (b) the use of non-food perennial crops (woody biomass and tall grasses) and lignocellulosic residues and wastes (woodchips from forest thinning and harvest residues, surplus straw from agriculture). 

Figure 1, Multistage hydrolysis of autohydrolyzed-extracted lignocellulosic residue, 2.0% on lignocellulosic residue each stage 20 min at 190°C...

The GC internal standard is usually hexacosane (C26) and/or tetracosane (C24) For complex samples, such as those represented by lignocellulose residues, it is advisable to add both of these internal standards The amount of each internal standard (C26 and/or C24) to be added is 0 5 mg/20 mg of extractive-free wood, 0 25mg/20mg of extractive-free straw, and lmg/5mg of milled wood lignin (Note 6)... 

Silylation the final CH2C12 solution of the thioacidolysis sample is again carefully dried over Na2S04, 5-10/d of this dried organic solution is trimethylsilylated (TMS) at room temperature with 50/i of N,0 bis (trimethylsilyl) trifluoroacetamide (BSTFA) and 5 1 of GC-grade pyridine in a 200-/d reaction vial fitted with a Teflon-lined screwcap For soluble lignin samples, the silylation is complete within a few minutes, for lignocellulose residues, silylation is complete within 2 to 4h In both cases and with well-dried samples, silylations performed in the aforementioned vials are stable for several days (at least 48 h)... 

The possible development of LA into a cross-over chemical between carbohydrates and petrochemicals has recently spurred the development of more efficient procedures for its production. Most start from cheap starting materials such as lignocellulose residues and waste paper in acidic medium at approx. 200 °C the theoretical yield of such a procedure is 0.71 kg kg-1 (see Fig. 8.36). In a patent application for a two-stage procedure the claimed yields were 62-87% of the theory, depending on the raw material [195]. A much simpler, extrusion-based procedure has been described but even when fitted with a second stage the yield was not better than 66% of the theory [196]. Efficient DSP is not trivial and the chromatographic separation that has been described [197] is obviously not compatible with the aimed-for commodity status of LA. Alternatively, the LA can be esterified in situ [197]. 

Aznar, M.P. Corella, J. Delgado, J. Lahoz J. (1993) Improved Steam Gasification of Lignocellulosic Residues in a Fluidized Bed with Commercial Steam Reforming Catlysts. Ind. Eng. Chem. Res., 32, 1-10. 

Saddler JN, Ramos LP, BreuU C (1993) Steam pretreatment of lignocellulosic residues. In Saddler JN (ed) Bioconversion of forest and agricultural plant residues. CAB International, Wallingford, p 73... 

Kirk-Othmer Encyclopedia of Chemical Technology 2006, 2/, 446. (d) Nicol, S. Life after death for empty shells. New Scientist 1991,129, 46. (e) Villas-Boas, S. G. Esposito, E. Mitchell, D. A. Microbial conversion of lignocellulosic residues for production of animal feeds. Animal Feed Science and Technology 2002, 98, 1. 

Sanchez C. (2009). Lignocellulosic residues biodegradation and bioconversion by fungi. 

In view of the projected large-scale usage of cellulase enzymes in bioconversion of lignocellulosic residues, there is a continuous renewed interest in search of novel sources of cellulases which produce these enzymes with desired novel properties that cause rapid hydrolysis of cellulose. Several research groups, including those from National Renewable Energy Laboratory (NREL), Genencor, Novozymes, etc., have reported improvements in one or more of these properties, especially with respect to thermal stability (Mousdale, 2010). It is pertinent to mention here that such an... 

TABLE 5 Microbial Strains Coproducing Cellulases and Xylanases on Lignocellulosic Residues... 

Early efforts for the efficient conversion of biomass into monomers were concentrated on the acidic transformation and on the fermentation of sugars obtained from sucrose, or from glucose after depolymerization of starch materials (potato, com). During the last two decades, however, more attention has been focused on other constituents of plant materials, such as cellulose and lignocellulosic residues. The current trend is indeed to avoid competition with food, offering new routes to C6 and C5 carbohydrates, for further transformation into value-added platform molecules. 

MODIFICATIONS REACTIONS NEW ADSORBENTS FROM LIGNOCELLULOSIC RESIDUES... 

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