Genetic diversity and antimicrobial activity of lactic acid bacteria in the preparation of traditional fermented potato product ‘tunta’

This research was supported by the Programa Nacional de Innovación para la Competitividad y Productividad (Innovate Perú), under the contract N° 223-FINCyT-IA-2013 and Fondo Nacional de Desarrollo Científico, Tecnológico y de Innovación Tecnológica (FON-DECYT), research project PROCYT N° 316-2011-CONCYTEC-OAJ from Peru.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy

Liquid-liquid equilibrium of water + PEG 8000 + magnesium sulfate or sodium sulfate aqueous two-phase systems at 35°C: experimental determination and thermodynamic modeling

Liquid-liquid extraction using aqueous two-phase systems is a highly efficient technique for separation and purification of biomolecules due to the mild properties of both liquid phases. Reliable data on the phase behavior of these systems are essential for the design and operation of new separation processes; several authors reported phase diagrams for polymer-polymer systems, but data on polymer-salt systems are still relatively scarce. In this work, experimental liquid-liquid equilibrium data on water + polyethylene glycol 8000 + magnesium sulfate and water + polyethylene glycol 8000 + sodium sulfate aqueous two-phase systems were obtained at 35°C. Both equilibrium phases were analyzed by lyophilization and ashing. Experimental results were correlated with a mass-fraction-based NRTL activity coefficient model. New interaction parameters were estimated with the Simplex method. The mean deviations between the experimental and calculated compositions in both equilibrium phases is about 2%