Studi Kinetika Hidrolisis Enzimatik Pati Singkong: Pengaruh Perbandingan Alfa-Amilase dan Glukoamilase Terhadap Gula Reduksi

Abstract

The kinetic study on enzymatic hydrolysis of cassava starch (Manihot esculenta) was studied. This hydrolysis experiment was carried out cassava starch at concentration of 200 g/L, using a test jar, with stirrer and water bath. The cassava starch was hydrolyazed by α-amylase and glucoamylase at 100 rpm, 90°C and pH 4.5. The effect of ratio of two enzymes, α-amylase and glucoamylase (1:1, 1:2, 1:3, 2:1 and 3:1) on the kinetic hydrolysis of cassava starch was studied, Increasing the ratio of α-amylase and glucoamide has an effect on the increase of reducing sugar concentration. The ratio of mass of α-amylase and glucoamide 1: 3, yields the maximum reduction sugar concentration was 93.45 g/L. The larger the mass of glucoamylase, the greater this enzyme in producing reducing sugars. This suggests that glucoamylase activity is more dominant in degrading the cassava starch or α-amylase unable to access the starch granule component, this enzyme can only hydrolyze the α-1,4 glycoside bond, which is far from the end of the chain and branch point, unlike glucoamylase capable hydrolyzes α-1,4 and α-1,6 complete glycoside bonds. Hydrolysis of cassava starch, using a mixture of α-amylase and glucoamylase at a ratio of 1: 1, substrate concentration  200 g/L, at temperature (60-90 °C), and pH 4.5, showed 1^st order reaction with reaction rate constant , k is 0.086; 0.106; 0.128 and 0.194 hours-1, respectively,  whereas the activation energy, Ea = 26.28 J / mol