Producing activated carbon from sesame stem and using it in the immobilization of Aspergillus niger glucoamlase

In this study, the experiments have been carried out in two stages. In the first step activated carbon obtained from sesame shell and activated carbon synthesis by microwave assisted chemical activation method using ZnCl2 activation. The effects of microwave power, microwave duration, different gases at microwave, activation temperature and raw material/chemical ratio parameters were examined in the activated carbon synthesis.The iodine number of the obtained activated carbones were determined and the higher ones were caracterized with BET surface area, SEM, TGA/TG and FTIR. Activated carbon with high BET surface area will be used for enzyme immobilization. In the second step, the covalent immobilization of Aspergillus niger amyloglucosidase on the obtained activated carbon functionalized with glutardialdehyde was studied. By optimizing the immobilization conditions, 100.00 % immobilization and activity yields obtained. Optimum pH (5.5) and optimum temperature range (55-60 oC) have not affected by immobilization. The Michaelis-Menten constants of free and immobilized enzyme were also determined by using Linewveaver -Burk plot. After immobilization, Vmax value has decreased from 1464.1 to 1342.3 μmol D-glucose / L.min, while Km value has decreased from 116.3 to 106.3 g maltodextrin / L. The immobilized enzyme didn't lose its initial activity after repeated twenty uses and after twenty days of storage. Maltodextrin was completely converted to glucose after two hours, by using an immobilized enzyme. Consequently, it can be said that immobilized Aspergillus niger amyloglucosidase obtained in the present study can be used in the industrial production of glucose syrup and in the other industrial applications.