Continuous laccase concentration in an aqueous two-phase system

An approach to describe continuous partitioning of Cerrena unicolor laccase in a PEG 6000-phosphate aqueous two-phase system was proposed. The laccase was separated from crude supernatant of C. unicolor-submerged culture, and all the experiments were carried out in 25 °C and pH 7 conditions. Masses of both phases and their compositions at phase equilibrium, as well as laccase activity concentrations at different mixing points, were measured in batch experiments. An empirical short-cut method was developed which allows for calculation of mass and volume fractions of the phases, laccase concentration factors, and laccase recoveries. Theoretical predictions were verified by several experiments carried out in a special mixer-settler unit with automatic substrate feed and continuous collection of separated phases. Required concentration of the laccase was possible to achieve in a one-step extraction process in the mixer-settler unit. The predictions of the short-cut method were compared to the results of experimental measurements of phase compositions, phase volume fractions, concentration factors and enzymatic yields at steady-state operation of the extraction unit. The values of experimental results lay well within the 10% error range of the predicted values.