Anais do Simpósio Latino Americano de Ciências de Alimentos
Anais do 14 SLACA - Simpósio Latino Americano de Ciência de Alimentos

Enzymes are immobilized to enhance their stability by hardening their structure and allowing recycling by making them insoluble. One of the immobilization methods is the formation of a covalent bond between the enzyme and an inert support. Thus, in this work, a commercial alkaline protease from Bacillus licheniformis (Protezyn APP 3000) was immobilized by covalent bonding in modified chitosan and its application in protein hydrolysis was evaluated. For this, the supports (5% m/v chitosan, 2.5% m/v chitosan and 2.5% m/v chitosan mixed with 2.5% m/v alginate) were prepared by dissolving the polymers in acetic acid, coagulating in sodium hydroxide and modifying with glutaraldehyde and ethylenediamine. Enzyme immobilization was performed in different solutions and reaction times. The best conditions observed were: 5% (m/v) chitosan support modified with glutaraldehyde only; immobilization solution with the enzyme diluted in distilled water and immobilization time of 2 h. Under these conditions, the amount of immobilized enzyme was 70%, efficiency was 34%, effectiveness was 48% and stability factor at 60 °C was 2.4 in relation to the free enzyme. Biochemical characterization indicated that the immobilized enzyme maintained the optimal pH and temperature of the free enzyme (pH 9 and 60 °C), but the immobilization expanded this range of action, resulting in a wide range of activity in adjacent conditions. When reused, the immobilized enzyme retained 47% of its initial activity after three cycles. Although the free enzyme showed greater hydrolytic activity on casein, hemoglobin and soy protein, the immobilized enzyme also showed a high performance on these proteins (78%, 75% and 82% of activity relative to the free enzyme, respectively), in addition to have been more efficient than the free enzyme in the hydrolysis of gelatin. Therefore, the immobilization conducted proved to be promising in the stabilization of a commercial protease that could still be optimized.