Partitioning of β-glucosidase from Trichoderma reesei in poly(ethylene glycol) and potassium phosphate aqueous two-phase systems: Influence of pH and temperature

This study evaluates the influence of pH and temperature on the partition coefficient of β-glucosidase and total protein in order to determine the best conditions for the purification of the enzyme in poly(ethylene glycol) (PEG) 4000 (8%, w/w) and potassium phosphate salt (13%, w/w) aqueous two-phase systems. The partition coefficient increased with pH and temperature for the ranges investigated (i.e., pH: 6.0–7.5; temperature: 25–55 °C). Yield and selectivity were key criteria for the selection of the optimum separation condition for enzyme purification. The highest selectivity was achieved at a pH of 6.5 and a temperature of 25 °C. A β-glucosidase yield greater than 92% was obtained in the bottom phase for pH values less than 7.0 and temperatures below 35 °C.