Effect of immobilized polygalacturonase from Mucor circinelloides ITCC-6025 on wine fermentation

Pectinases are among the most widely distributed enzymes in bacteria, fungi, and plants. Almost all the commercial preparations of pectinases are produced from fungal sources. Mucor circinelloides ITCC-6025 produced polygalacturonase when grown in Riviere's medium containing pectin (methyl ester) as the sole source of carbon. Immobilization of purified polygalacturonase was done on silica gel with 86% efficiency. The enzyme took 60 Min to bind maximally on the support. The immobilized enzyme showed maximum activity at a temperature of 45°C (4.57 U/mg) and pH 5.4. The immobilized enzyme was reused for four cycles as it retained almost 55% of its activity. The immobilized enzyme treatment increased the formation of higher alcohols and phenolics during the course of wine formation from apple and plum juices, whereas there was a decrease in the amount of carbohydrates. The enzyme treatment also resulted in clarification of wine; there was an increase in transmittance at 650 nm (201.78% in the case of apple wine and 223.4% in the case of plum wine) as compared to the control (untreated wine).