Biomass, definition

Hemicellulose [9034-32-6] is the least utilized component of the biomass triad comprising cellulose (qv), lignin (qv), and hemiceUulose. The term was origiaated by Schulze (1) and is used here to distinguish the nonceUulosic polysaccharides of plant cell walls from those that are not part of the wall stmcture. Confusion arises because other hemicellulose definitions based on solvent extraction are often used in the Hterature (2—4). The term polyose is used in Europe to describe these nonceUulosic polysaccharides from wood, whereas hemicellulose is used to describe the alkaline extracts from commercial pulps (4). The quantity of hemicellulose in different sources varies considerably as shown in Table 1. 

Chemurgy is defined as that branch of appHed chemistry devoted to industrial utilization of organic raw materials, especially from farm products. A more modem and general definition for chemurgy is the use of renewable resources particularly biomass, usually plant or microbial material, for materials and energy (see Fuels frombiomass Fuels fromwaste). 

Biomass concentration is obtained from definition as substrate is utilised it is converted to cells or biomass ... 

Cell growth and metabolic activities are similarly described as a simple chemical reaction. It is also necessary to establish a definite formula for dry cell matter. The elemental composition of certain strains of microorganism is defined by an empirical formula CHaO/3Ns. The general biochemical reaction for biomass production is based on consumption of organic substrate, as shown below. Substrate oxidation is simplified in the following biochemical oxidation ... 

From the above biomass production, calculate the yield coefficients. Based on definition, the yield of biomass on glucose means how much biomass is produced per gram of glucose utilised in a cell. The yield of biomass on glucose is calculated as follows ... 

An important benefit of the isotopic approach is that below-ground biomass values are not required. The 13C natural abundance isotopic carbon budget approach is based on C3 plants having lower 13C value than C4 plants (Ehleringer 1991 Clay et al. 2006) and that the signatures can be tracked by placing C3 plant residue into a soil derived from C4 plants or vice versa. In these calculations, several definitions are needed. These definitions include... 

The impact of the root to shoot ratios on calculated maintenance requirements is important because root to shoot ratios are highly variable and almost always underestimate below-ground biomass. Amos and Walters (2006) reported that the net below-ground C deposition in com at physiological maturity was 29% 13% of the shoot biomass (leaves, stems, and husks) in 41 studies. The use of these values is further complicated by the use of different definitions for root to shoot ratio. Converting Amos and Walters (2006) units to units used by Johnson et al. (2006) would reduce the reported values from 0.29 to 0.15 (harvest index 50%). 

Renewable electricity (RES-E) Electricity generated from renewable non-fossil energy sources, i.e., wind, solar, geothermal, wave, tidal, hydropower, biomass, landfill gas, sewage treatment plant gas and biogas (this corresponds to the definition in Directive 2001/77/EC on renewables, Article 2). 

Using our definition for alkalinity or ANC whereby any decrease (increase) in concentrations of base cations (e.g., K+, Ca2+, Fe2+, etc.) or any increase (decrease) in concentrations of "acid anions" (e.g., NO3, HPO2, SOf, etc.) is accompanied by a decrease (increase) in alkalinity. Thus, as illustrated in Fig. 5.17 net synthesis of terrestrial biomass (e.g., on the forest and forest floor, where more cations than anions are taken up by the plants (trees), is accompanied by a release of H+ to the environment. 

The role of biomass in the natural carbon cycle is not well understood, and in the light of predictions of a future atmospheric energy balance crisis caused by carbon dioxide accumulation, in turn the result of an exponential increase in the consumption of carbon fuel, the apparent lack of concern by scientists and policy makers is most troubling. Yet there is no other single issue before us in energy supply which will require action long before the worst effects of excess production will be apparent. The only satisfactory model is the action taken by the R D community with respect to the SST in nitric oxide potential and chloro-halocarbon emissions, when it was realised that the stratospheric ozone layer was vulnerable to interference. Almost all other responses to pollution" have been after definitive effects have become apparent. 

The definition of the yield coefficient may now be used to derive an expression for the biomass concentration, since by substituting ... 

Several hypotheses of the possible relationship between the deposition of the cherty iron formation and the activity of various primitive organisms have been defined and repeatedly proofs have been offered to support the occurrence of definite biota. In fact, some indication is available for the assumption, that life was abundant at the time and place of deposition of the BIF and that iron formations themselves were deposited as a result of biological processes. It is presumed in this context, that iron-bacteria reacted with the oxygen acceptor Fe2 + in solution and then deposited the trivalent and/or trivalentdivalent iron as precipitated compounds along with other residues resulting from biomass. All these components... 

Accordingly, biomass has become increasingly popular again. The reasons are simple. Biomass is, per definition, renewable and sustainable if the amount utilized equals the amount that is naturally replenished, for instance, by replanting in the case of wood utilization (Figure 16.1). Broadly speaking, biomass can be utilized as (1) a source of renewable chemicals and materials and (2) an energy source. 

Because the Evening Primrose is a biannual, the stem shoots up only in the second year of growth. In the first year, a taproot is put down. In the second year a sprout shoots up. Producing a biomass material only every other year is a definite drawback to its use as a biofuel however, the density of its xylem material is significantly greater than that of the other candidate plants, actually giving the evening primrose a competitive output. 

By definition, biomass corresponds to any organic matter available on a recurring basis (see Figure 1.1). The two most obvious types of biomass are wood and... 

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