Enzyme mass transfer coefficient in a sieve plate extraction column

Abstract

The extraction of α-amyloglucosidase was investigated in a sieve plate column using the aqueous two-phase systems formed by sodium sulphate-polyethylene glycol(PEG)-water. The effects of phase flow rate, number of orifices, orifice size, number of plates and phase composition on the fractional dispersed phase hold-up ϵ D and volumetric mass transfer coefficient K D a were investigated in a 60 mm internal diameter sieve plate extraction column operated in a semi-batch manner. It was found that the total hold-up ϵ T, dynamic hold-up ϵ D and volumetric mass transfer coefficient K D a increased with an increase in PEG-rich dispersed phase velocity, number of orifices and orifice size, and decreased with increasing phase concentrations. The total hold-up ϵ T and volumetric mass transfer coefficient K D a decreased, while the fractional dispersed phase hold-up ϵ D increased, with an increase in the plate spacing. Rational correlations were developed for phase hold-ups and mass transfer coefficients. The contributions to mass transfer during the formation, rise and coalescence of drops were also calculated. It was found that a significant amount of mass transfer occurs during the rise and coalescence stages, while during drop formation it is negligible. Correlations were developed for true mass transfer coefficients ( k D) r and ( k D) c.