The resulting pretreated biomass stream contains major components (sugar, lignin, and so on) and minor components like organic extractives, water-soluble low molecular weight compounds such as furfural, hydroxymethylfurfural (HMF), and vanillin, as well as other larger degradation products [ 2].
The organic solvent extractives, the total water extractives, and the non-extractives (except protein) were measured by TAPPI methods [12, 13, 14, 15, 16, 17], with minor modifications as described previously [18].
The extractive agent, water, feeds the column on a scheduled basis of facilitate the separation.
Figure 1 characterizes the composition of the total extractives in water and ethanol extractions.
In general, the differential-TG (DTG) curves of lignocellulose biomass often show three main peaks: one reflects the evaporation of extractives or water at 100 200 °C, the others stand for degradation of cellulose and lignin at 300 350 and 300 500 °C, respectively.
For COD calculations, 90% degradation was assumed for soluble sugars, organic acids, ethanol, enzymes and 50% degradation for residual carbohydrates, extractives and water soluble lignin [ 47].
The combined pretreatment increased the removal percentage of xylan, lignin, extractives, and water up to 63.8, 40.2, 32.3 and 58.7 %, respectively.
As seen in Table 1, when compared with the composition of the untreated RS, alkali pretreatment alone could increase the cellulose content by 40.5%%, while the xylan, lignin, extractives, and water contents were reduced by 42.9, 23.4, 10.8, and 44.3 %, respectively.
Constituents measured were total ash (structural and non-structural), protein (structural and non-structural), sucrose, water extractives, ethanol extractives, starch, lignin, glucan, xylan, galactan, arabinan, fructan or mannan, and acetic acid.
Water extractive sugars accounted for over 20% total sugars recovered.
We conclude that there is a pressing need to institutionalize HIA in the developing world, as a consequence of current predictions of major extractive industry and water resources development, with China's investments in these sectors across Africa being particularly salient.
