S. Jarudilokkul et al., Lysozyme extraction from egg white using reverse micelles in a Graesser contactor: Mass transfer characterization, BIOTECH BIO, 69(6), 2000, pp. 618-626
The gentle mixing characteristics of a Graesser contactor can help to avoid
the formation of stable emulsions, which is one advantage of this type of
contactor when used with reversed micellar extraction. In this study, the p
erformance of the Graesser contactor in lysozyme extraction from hen egg wh
ite is investigated. The concentration profile of lysozyme in the aqueous a
nd organic phases indicated that, while substantial axial mixing occurred i
n the contactor, the extraction yield was in the range of 97% to 99%. The n
umber of mass transfer units (N-ox) was determined using a diffusion model,
and the influence of aqueous-to-organic phase flow ratio, rotor speed, and
total throughput on contactor performance was studied. It was found that t
he diffusion model could describe quite well the extraction of lysozyme fro
m hen egg white using reversed micelles. The optimal conditions for the ext
raction at steady state were found to be a rotor speed of 5 rpm, an aqueous
-to-organic phase flow ratio of 60:20 mL/min, and a total throughput of 80
mL/min. In addition, back-extraction was also performed using the conventio
nal method (1.5 M KBr at pH 11.5) in the contactor. It was found that this
mass transfer was not well described by a diffusion model, although 85% of
the lysozyme could be recovered with the operating conditions used: a rotor
speed of 10 rpm, and an aqueous-to-organic flow rate of 10:10 mL/ min. (C)
2000 John Wiley & Sons, Inc.