Biomass as a Renewable Resource

India and southern Africa but many well-forested developed countries still use significant amounts of wood for burning. 

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Obviously, the photosynthetic potential of plants with respect to the production of biomass as a renewable resource in sustainable production cycles has found actual attention and has been defined in many recent national and international research programs. A special variant of such endeavors has been formulated as New Phytotechnology by the Austrian group of Othmar Ruthner and coworkers [7] and this will be dealt with in the following section. 

To really appreciate the rationale behind current studies of microbial xylanases, it is necessary to consider a broad view that takes into account not just their intrinsic interest, but also their undoubted commercial potential. The structural polysaccharides cellulose and hemicellulose together account for greater than 50% of plant biomass and are consequently the most abundant terrestrial organic molecules. The value of plant biomass as a renewable resource is thus immediately apparent (23). 

Summing up, it is the production and supply of biomass rather than the demand for fuel or materials which limits the use of biomass as a renewable resource. In this context it is important to note that chemical production requires far lower amounts of carbon than fuel production. For example, in the United States, the chemical products segment consumed just over 3% of the total US petroleum consumption in 2007 (FitzPatrick et al., 2010). This opens an economic opportunity for the development of bio-sourced chemical products since the value of the chemical industry is comparable to the fuel industry, but requires only a fraction of the biomass (FitzPatrick etal.,2010). 

Xylan-type polysaccharides are the main hemicellulose components of secondary cell walls constituting about 20-30% of the biomass of dicotyl plants (hardwoods and herbaceous plants). In some tissues of monocotyl plants (grasses and cereals) xylans occur up to 50% [6j. Xylans are thus available in huge and replenishable amoimts as by-products from forestry, the agriculture, wood, and pulp and paper industries. Nowadays, xylans of some seaweed represent a novel biopolymer resource [4j. The diversity and complexity of xylans suggest that many useful by-products can be potentially produced and, therefore, these polysaccharides are considered as possible biopolymer raw materials for various exploitations. As a renewable resource, xylans are... 

Biomass is a renewable resource from which various useful chemicals and fuels can be produced. Glycerol, obtained as a co-product of the transesterification of vegetable oils to produce biodiesel, is a potential building block to be processed in biorefineries (1,2). Attention has been recently paid to the conversion of glycerol to chemicals, such as propanediols (3, 4), acrolein (5, 6), or glyceric acid (7, 8). 

An overview of cellulose-based chemicals and fuels systems is presented in Figure 1. In this cyclic system, demand for fuels and chemicals leads to the organization of factors of production (land, labor, capital, etc.) for the generation of biomass for use as a renewable resource. The plant culture activity is called silviculture if trees are the desired biomass or agriculture if herbaceous plants are grown... 

The potential for carbon capture and sequestration (CCS) and precombustion decarbonization expand possibilities for the sustainable use of conventional fossil energy carbonthis area during the 2009-2015 term may be gasification related. Currently, Task 27 - Near-Term Market Routes to Hydrogen by Co-utilization of Biomass as a Renewable Energy Source with Eossil Euels addresses many of these issues. This task seeks to advance the development... 

As a general rule, it is best if feedstocks come from renewable sources rather than depletable resources. A biomass feedstock, for example, can be obtained as a renewable resource grown by plants on land, whereas a petroleum-based feedstock is obtained from depletable crude oil resources. However, the environmental trade-offs between these two sources may be more complex than they first appear in that the petroleum feedstock may be simply pumped from a few wells in Saudi Arabia, whereas the biomass may require large areas of land, significant quantities of fertilizer, and large volumes of irrigation water for its production. Another important decision is whether or not the feedstock should be made entirely from virgin materials or at least in part from recycled material. 

In summary, much work has been done utilizing the hydroxyl groups present on lignin with the production of numerous materials with potential industrial uses. The above results and the ready availability of vast quantities of lignin encourage further development of lignin as a renewable resource feedstock. As our sources for synthetic and oil-based feedstocks decreases, the renewable biomass must be considered as an alternative. 

Depletion of fossil oil resources and concern about environmental pollution, especially heavy metals and greenhouse gases, have brought biomass into focus as a renewable source of raw materials for large-scale chemicals and energy production (1). The biomass refinery of the future will require a powerful toolbox of processes for converting complex plant matter into useful commodity and specialty products. 

There are four principal ways in which biomass is used as a renewable energy resource. The first, and most common, is as a fuel used direcdy for space and process heat and for cooking. The second is as a fuel for electric power generation. The third is by gasification into a fuel used on the site. The fourth is by conversion into a Hquid fuel that provides the portability needed for transportation and other mobile appHcations of energy. Figure 7 shows the varied pathways which can be followed to convert biomass feedstocks to useful fuels or electricity. 

Use of Biomass for Hydrogen Production or as a Renewable Carbon Resource... 

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