2020-01

International Journal of Biological Macromolecules (Issue : 01418130) (Volume : 142)

This study was aimed the covalently immobilization of Aspergillus niger amyloglucosidase (ANAG) onto activated carbon (AC) obtained from sesame seed shell. AC was firstly functionalized with ethylenediamine, and after then activated with glutaraldehyde. 99.80% immobilization yield and 99.83% activity yield were obtained as the result of optimization of immobilization conditions (pH and molarity of immobilization buffer, AC amount, and reaction time). The optimum pH (5.5) and the optimum temperature range (55–60
C) for ANAG were not affected by immobilization. After immobilization, Vmax value decreased from 1464.1 lmol D-glucose/L.min to 1342.3 lmol D-glucose/L.min, while Km value decreased from 116.3 g maltodextrin/L to 109.9 g maltodextrin/L. The immobilized enzyme retained 99.30% and 98.30% of its initial activity, respectively after twenty repeated uses and after twenty days of storage in 5 mL sodium phosphate buffer (0.1 M, pH 5.5) at +4
C in a refrigerator. Finally, glucose syrup was produced from maltodextrin solution having 1% (w/v) concentration by using the immobilized ANAG. Maltodextrin was completely converted to glucose after four hours. Consequently, it can be said that the immobilized ANAG obtained in this study can be used in the industrial production of glucose syrup.

2018-05

Analytical Letters (Issue : 17) (Volume : 51)

The preparation of activated carbon from sesame shells as raw precursor was investigated in the study by sequentially applying microwave and conventional heating methods assisted by zinc chloride activation. The optimizisation of experimental parameters including microwave power, microwave treatment time, conventional activation time, conventional activation temperature and zinc chloride concentration ratio for the microwave and conventional heating method was performed. The characterization of the prepared activated carbon was done by thermogravimetric and differential thermal measurements, infrared spectroscopy, scanning electron microscopy and specific surface area analyses. The maximum surface area of 1254 m2/g for the prepared activated carbon was obtained at a microwave power of 750 W, a microwave treatment time of 20 min, an activation time of 45 min, an activation temperature of 500°C and zinc chloride concentration ratio of 1:1. Methylene blue and iodine adsorption capacities for the prepared activated carbon were 103 and 1199 mg/g, respectively.