Characteristics of invertase partitioned in poly(ethylene glycol)/magnesium sulfate aqueous two-phase system

Abstract

The goal of this study was to determine some characteristics of Baker's yeast invertase partitioned with poly(ethylene glycol)/MgSO 4 aqueous two-phase system (ATPS). Under optimized conditions [PEG-3000 (15%, w/w) and MgSO 4 (23%, w/w) with 5% (w/w) MnCl 2 at pH 5.0] yeast invertase was partitioned by using an ATPS with purification factor of 6.2-fold and activity recovery of 217.7%, respectively. The yeast invertase was characterised with respect to its activity and stability at various pH and temperature ranges. Optimum pH and temperature were determined at pH 5.5 and 60 °C, respectively. The enzyme was very stable in the range of pH 4.0–7.0 and more than 95% of its initial activity was recovered. The yeast invertase was also stable at the temperature range of 4–50 °C and retained nearly about 98% of its initial activity at 50 °C. Kinetic parameters, K m and V max using sucrose as substrate were measured as 24.1 mM and 35.5 U, respectively. MnSO 4 and MnCl 2 efficiently enhanced the activity and also showed an activator effect for invertase. Relative activities were found as 151% and 156% for MnSO 4 and MnCl 2, respectively. The biochemical properties of the yeast invertase partitioned in an ATPS make the enzyme good candidates for several industrial applications.