Gelatin-Immobilized Manganese Peroxidase with Novel Catalytic Characteristics and Its Industrial Exploitation for Fruit Juice Clarification Purposes

In the present study, glutaraldehyde (GLA) activated gelatin hydrogel was used as a solid support to encapsulate the manganese peroxidase (MnP; E.C. 1.11.1.13) produced by Ganoderma lucidum IBL-05 under pre-optimized growth environment. Through gelatin-assisted immobilization, a maximal of 83.2 +/- 2.91 % immobilization yield was achieved at optimum conditions of gelatin; 20.0 % (w/v), GLA 0.25 % (v/v) after 2 h activation time using 0.6 mg/mL of enzyme concentration. In contrast to aqueous form, the insolubilized MnP presented its maximum activity at pH 6.0 and 60 A degrees C. Inevitably, enzyme immobilization significantly (P < 0.05) increased the thermal stability profile of in-house isolated MnP. At 60 A degrees C, maximum activity of free MnP decreased to 14.2 A +/- 1.4 %, whereas immobilized MnP retained 70.18 A +/- 3.2 % of its original activity after 120 min. To explore the industrial applicability of MnP, the immobilized MnP was tested for apple and orange fruit juice clarification features in a packed bed reactor system. The immobilized MnP showed commendable results in the de-bittering's of investigated fruit juices, decreasing 42.7 % of the original apple juice color and 36.3 of its turbidity. Whereas, the color and turbidity reduction characteristics of orange juice were 51.5 and 43.6 %, respectively. After six consecutive cycles, the immobilized-MnP was able to retain more than 60.0 % of its initial activity. Collectively, catalytic, thermo-stability and clarity amelioration features of the gel-entrapped MnP suggest a high potential of enzymatic treatment for biotechnological exploitability.