الفهرس 
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Abstract
throughout the present investigation, as the most abundant agricultural residues. The isolation and determination the quality of resulted hemicellulose from these lignocellulosic materials were studied. Also, chemical composition of crude and extracted of the major components from lignocellulosic residues were determined.
from these results the cellulose content for the three lignocellulosic materials were found to be 33.35, 35.64 and 37.74% for peanut pods, midrib and wood powder residues, respectively.
On other hand, the crude lignocellulosic materials contained amounts of hemicellulose reached its highest content (38,59 %) for peanut pods residue while midrib residue contained less amount i.e (36.03%). However, the hemicellulose from wood powder residue was found to be (31.98%).
The isolated hemicellulosic polymers contained a high percentage of hemicellulose components i.e. 71.30, 70.56 and 69.78 for midrib residue, wood powder residue and peanut pods residue, respectively.
The influence of various parameters i.e. pH, temperature, enzyme concentration and isolated hemicellulose concentration on the reaction activity and reaction velocity of hemicellulase enzyme were studied.
The hemicellulase enzymes showed its maximum activity at pH 4.8 for both xylan and isolated hemicellulose from midrib residue and the optimum activity amounted to 11.45 mM xylose /L/min for the first and 9.44 mM xylose /L/min for the second, respectively. On the other hand, the maximum reaction activities were found to be 9.56 and 7.38 mM xylose /L/min for both isolated hemicellulose from peanut pods and wood powder residues, at pH equalled to 5.0, respectively.
Also, the hemicellulase enzymes showed its maximum activity at temperature 55°C for xylan and isolated hemicellulose from peanut pods and wood powder residues while the maximum activity was 50°C for isolated hemicellulose from midrib residue.
On the other hand, the optimum enzyme concentration was 0.05mg/m1 for xylan as standard substrate and 0.07 mg/ml for other substrates under investigation.
The maximum reaction velocity and Michaeles constant for hemicellulase enzyme were determined by using xylan and isolated hemicellulose from different above-mentioned materials.
The maximum reaction velocity (Vmax) for hemicellulase enzyme by using xylan equalled 273.4 mg/ml, while the Michel’s constant (Km) was found to be 0.160 g/L. On the other hand, the (Vmax) valuse for this enzyme with isolated hemicellulose from peanut pods; midrib and wood powder residues were 253.3, 196.7 and 220.0 mg/ml, respectively. The Km values were found to be 0.125, 0.160 and 0.175 g/L for the isolated hemicellulose from above-mentioned materials.
Finally, the enzymatic succharification of isolated hemicellulose from different lignocellulosic wastes under investigation were determined.The maximum value of saccharification process was 86.6% for xylan as standard substrate at concentration of 25g/L after 48 h under optimum conditions of hemicellulase enzyme. On the other hand, the maximum values of saccharification for isolated hemicellulose from peanut pods, midrib and wood powder residues were 81.0, 81.2 and 79.6% respectively at substrate concentration of 35g/L and 45g/L for incubation period 96h under optimum conditions of hemicellulase enzymes.