<p>Xylanase is an enzyme that catalyzes the reaction of xylan hydrolysis into xylose. The free enzyme can be used only once, therefore it needs to be made in the form of immobilization. This study aims to determine the optimum conditions for immobilization of xylanase using an acid-activated zeolite. The xylanase immobilization was performed on variations of shaking time (1-5) hours, variation of xylanase concentration (2 - 4 mg / mL) using 0.1 g zeolite at room temperature and a shaking rate of 100 rpm. The amount of xylanase adsorbed on the zeolite was determined by spectrophotometry using the Biuret reagent and the immobilized xylanase activity formed was determined spectrophotometrically using a DNS reagent The results showed that the optimum condition of xylanase immobilization at zeolite was achieved at 3 hrs shaking time and xylanase concentration 3.5 mg / mL with xylanase adsorbed of 156.5 mg/g zeolite and activity 26.67 units.</p>
Pillarization of layered double hydroxides with polyoxometalate K 4 [α-SiW 12 O 40 ]•nH 2 O at various times i.e. 3, 6, 9, 12, 24, 36 and 48 hours has been done. The pillared product was characterized by FT-IR spectrophotometer and XRD. The optimum pillared layered double hydroxides of polyoxometalate K 4 [α-SiW 12 O 40 ]•nH 2 O was used as adsorbent of procion red dye. The results of characterization using FT-IR spechtrophotometer is not yet show the optimum pillaration process. The characteritation using XRD the successfully of pillared layered double hydroxides of polyoxometalate K 4 [α-SiW 12 O 40 ]•nH 2 O showing the existence of diffraction angle 8.5 o with intensity 355. Furthermore, the pillared layered double hydroxides of polyoxometalate K 4 [α-SiW 12 O 40 ]•nH 2 O with time variation of 12 hours was applied as adsorbent of procion red dye. The results show the adsorption rate was 0.523 min-1 , the highest of absorption capacity at 70 o C was 10.8 mol/g, the higest energy of absorption 70 o C was 125 kJ/mol. The enthalpy (∆H) and entropy (∆S), decrease as the increasing consentration of procion red dye.
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