Kinetic and Thermodynamic Characterization of two Polygalacturonases Isolated from the Digestive Juice of the Snail Limicolaria flammea

Polygalacturonases are extensively used in food industries for pectic substances degradation. In this paper, we investigate on thermal stability parameters of two Polygalacturonases previously isolated from digestive juice of the snail Limicolaria flammea for several industrial applications such as fruit juice clarification. Thermal inactivation was carried out in the temperature range of 55°C to 80°C from 15 to 120 min. All results were statistically analysed. The results shown that thermal inactivation of studied acid phosphatases follows first order kinetics. At their optimum temperatures, these enzymes showed high half-lives ranging from 462.06 to 630.10 min and D values from 1535.00 to 2093.64 min suggesting that these two enzymes had a large thermal stability. The high values of ΔG# (93.96 to 94.97 kJ/mol) reveal a better resistance to denaturation. The relatively high activation energies (from 120.35 to 129.13 kJ/mol) and average enthalpy values (from 117.67 to 126.44 kJ.mol−1) could corroborate the good stability of these biocatalyst. All these results suggest that Polygalacturonases from digestive juice of the snail Limicolaria flammea may be profitably exploited in future food industrial applications.