The adsorption of Methylene Blue (MB) and Acid Orange 7 (AO7) dye onto Ananas Comosus Mixed Peels and Leaves (ACMPL) were carried out by conducting four different parameters such as initial concentration, pH, dosage of adsorbent, and contact time. Effect of initial concentration for both dyes showed that higher initial concentration would take longer contact time to attain equilibrium due to higher amount of adsorbate molecules. The effect of pH showed highest percentage removal for MB is at pH 9 which is 95.81%. Meanwhile for AO7 the highest percentage removal is 31.06% at pH 3. The percentage removal of MB had reached the equilibrium at dosage 0.5g while AO7 keep increasing with the increment of adsorbent dosage. The percentage removal of MB and AO7 had increased until hour 2.5 which was from 72.5% to 86.93% and 19.441% to 36.89% respectively and reached equilibrium at 3 hour contact time.
Cyclodextrin (CD) is a non-reducing maltooligosaccharides which able to form inclusion complexes with many hydrophobic molecules, changing their physical and chemical properties. With these properties, CD has been discovered to have numerous applications in food industries, pharmaceutical, agricultural and environmental engineering. CD is produced by the enzymatic reaction between cyclodextrin glucanotransferase (CGTase) and starch. Various enzyme immobilization techniques such as adsorption, entrapment, encapsulation and cross-linking have been applied to improve the production of CD. Some of the immobilization parameters such as contact time, agitation rate and pH of the immobilization solution play a vital role in enzyme immobilization process, in order to achieve high production of CD. In the present study, the CGTase from Bacillus licheniformis was immobilized on polyvinylidene difluoride (PVDF) hollow fiber membrane via adsorption technique. The efficiency of enzyme immobilization appears to be affected by various factors (immobilization parameters) such as contact time, agitation rate and pH. Therefore, the effect of contact time (6-72 h), agitation rate (50-250 rpm) and pH (3-10) on the immobilization of CGTase on PVDF hollow fiber membrane were investigated in this study. The immobilized CGTase exhibited the highest immobilization yield of 69.37% under the conditions of 24 h contact time, 100 rpm and pH 7.0. Therefore, the influence of the immobilization parameters during the enzyme immobilization process is vital in order to achieve the high production of CD. Hence, high immobilization yield contributed to the high production of CD which in turn may be beneficial for the industrial purposes.
The production of cyclodextrin (CD) over the years has been increasing due to the numerous applications in industries such as in food, cosmetic, pharmaceutical and agricultural industries. However, cyclodextrin glucanotransferase (CGTase) which involved in the enzymatic reaction on the production of CD is unstable and easily denatured at extreme conditions resulted in low CD production. Hence, the enzyme immobilization technique is introduced to overcome these problems and subsequently increase the production of CD. In the present study, the CGTase was immobilized on hollow fiber membrane to increase the production of CD during the reaction. The effect of reaction conditions (types of starch, concentration of starch, temperature and pH) of the immobilized enzyme on the production of CD were investigated. Among the three types of starch tested, the soluble potato starch was the most suitable substrate for the production of CD with 4.13 mg/mL. In addition, by using 3% (w/v) of the soluble potato starch, the production of CD was 5.22 mg/mL . The optimal reaction temperature and pH were found to be at 40°C and pH 6 with 5.21 mg/mL and 4.62 mg/ml of CD, respectively. The immobilized enzyme exhibited a 1.3-3-fold increase in CD production compared to the free enzyme. Therefore, the hollow fiber membrane is suitable to be used as a support for enzyme immobilization with the high production of CD.
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