Production of high fructose syrup by using invertase that immobilization on Iraqi bentonite

Abstract

The using of immobilization between invertase and bentonite by glutaraldehyde resulted to immobilized 93% of the amount of total free enzyme, the pH optimum of free and immobilized enzyme was 5, the free enzyme was stable in the pH range from 3 to 7 by relative activity of the highest from 70% at pH 3, but it lost about 50% of the original ativity at pH 8, the immobilized enzyme showed higher stability in pH range from 3 to 8 by relative activity of the highest from 80% at pH 3, but it lost about 30% of the original ativity at pH 8, The results was showed that the optimum temperature for free and immobilized enzyme activity were 45 and 55 °C respectively, while it was observed that the free enzyme was stable at 50 °C for 30 minutes, after that, enzyme activity beginning decrease to lose more than 90% of its original activity at 70 °C, but immobilized enzyme was showed higher heat stable, it was stabile at 60 °C for 30 minutes, after that, enzyme activity beginning decrease to lose more than 80% of its original activity at 70 °C, the activity of immobilized enzyme was stabile for 21 days, but it lost 90% of its original activity after 30 days of storage at 4 °C, while free enzyme was stabile for 5 days, but the enzyme activity beginning decrease to lose all activity after 19 days of storage at 4 °C, and when determining the reaction time for production of high fructose syrup depending of release glucose percentage estimated from sucrose by immobilized enzyme activity, the results showed that the percentage of sucrose hydrolyzed was 32% after 10 minutes of reaction started, then it increase to be 71% after 20 minutes and up to 93% after 30 minutes and settled on this range up to the time of reaction (30 minutes), the results also showed the effect number of times used in immobilized enzyme activity (cycle number) that the immobilized enzyme was Keep all its activity after 26 consecutive used by 30 minute of on used, and after 50 consecutive used, immobilized enzyme was keep about 76% of its primary activity.