Lignocellulose utilization process

Wood hydrolysis has been limited to cellulose degradation by cellulase enzymes. These en mes are typically low activity and highly inhibited by the glucose product. As mentioned above, mild acid pretreatment has been found to be an important first step in the biomass utilization process. The pretreatment is used both to break down the hemicellulose to sugars and to disrupt the lignocellulosic structure and tlie crystallinity of the cellulose. 

For lignocellulose utilization, fermentation and processing, scale-up is an obvious necessity. Scaling up usually turns out to be more complicated and refractory than anticipated. Time, money, ingenuity and well-trained, interdisciplinary workers are necessary to make the transition to a level of production that would be appealing to industry. 

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). 

NREL (National Renewable Energy Laboratory). Lignocellulosic biomass to ethanol process design and economics utilizing co-current dilute add prehydrolysis and enzymatic hydrolysis for com stover. Golden, CO US (2002). Report available on web http //www.mel.gov/ docs/ fy02osti/32438.pdf... 

Lignocelluloses are freely available in the environment as residues from crop plants and trees and there has been a great effort in recent years to develop effective and economic processes for their utilization. However, outside the mushroom industry, few cost-effective options have been identified. This led Wood (1) and Lynch (2) to echo the comments of Thaysen and Bunker... 

Recent work by the USDA and Kcnaf International (Texas) has demonstrated the potential of both growing and processing kcnaf fibers for newsprinl and other paper products in the United States. Another promising potential use for vegetable fibers is in the new lignocellulosic-hased composites under development in various parts of the industrialized world. Such products are already utilized in the automotive industry for automobile interior door and head liners and as trunk liners. 

Lignocellulosic Biomass to Ethanol Process Design and Economics Utilizing Co-Current... 

Aden, A., Ruth, M., Ibsen, K., Jechura, J., Neeves, K., et al., Lignocellulosic Biomass to Ethanol Process Design and Economics Utilizing Co-Current Dilute Acid Prehydrolysis and Enzymatic Hydrolysis for Corn Stover NREL Report No. TP-510-32438 available online at URL http //www.nrel.gov/publications/ National Renewable Energy Laboratory Golden, CO, June, 2002, 2002 p. 154. 

Chemical modification reactions continue to play a dominant role in improving the overall utilization of lignocellulosic materials [1,2]. The nature of modification may vary from mild pretreatment of wood with alkali or sulfite as used in the production of mechanical pulp fibers [3] to a variety of etherification, esterification, or copolymerization processes applied in the preparation of wood- [4], cellulose- [5] or lignin- [6] based materials. Since the modification of wood polymers is generally conducted in a heterogeneous system, the apparent reactivity would be influenced by both the chemical and the physical nature of the substrate as well as of the reactant molecules involved. 

Utilization of wood-biomass residues as well as waste polymers is the important direction of recent research activities. It is known that direct catalytic liquefaction of plant biomass can be used to produce liquid fuels and chemicals [1,2]. Co-pyrolysis and co-hydropyrolysis processes have the potential for the environmentally friendly transformation of lignocellulosic and plastic waste to valuable chemicals. 

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