Integration and intensification of bioseparations : a role for pellicular solid phases in combinatorial cell disruption and fluidised bed adsorption
The development of a rapid and simplified primary capture step for the direct
selective recovery of intracellular proteins from particulate-containing yeast disruptate
in the circumvention of problems associated with conventional fluidised bed/expanded
bed adsorption has been undertaken. A protoype pellicular adsorbent, designed for
intensified fluidised bed adsorption processes, was assembled by the three-phase
emulsification coating of porous agarose upon a zirconia-silica solid core.
The adsorbent, designated ZSA, was subj ected to physical and biochemical
comparison with the performance of two commercial adsorbents (Streamline and
Macrosorb K4AX). Bed expansion qualities and hydrodynamic characteristics (N, Daxl
and Bo) of ZSA demonstrated a marked robustness in the face of elevated velocities (up
to 550 cm/h) and biomass loading (up to 30% ww/v) disrupted yeast cells. Cibracron
Blue derivatives of the pellicular prototype (ZSA-CB), evaluated in the batch and
fluidised bed recovery of glyceraldehyde 3-phosphate dehydrogenase (G3PDH) from
unclarified yeast disruptates, exhibited superior capacities and adsortionldesorption
performances to the commercial derivatives.
These advanced physical and biochemical properties facilitated a demonstration
of the direct coupling of bead-milling and fluidised bed adsorption in a fully integrated
process for the accelerated recovery of G3PDH from yeast. The practical feasibility and
generic applicability of the direct integration in the same time frame of cell disruption
with the capture of intracellular products has been demonstrated. The application of a
multi-fluidised bed system (MFBS), where each bed is sequentially operated on-line to
the disrupter to achieve a repetitive operation of this cycle was proposed and studied.
The generic application of such pellicular adsorbents and integrated processes to
the recovery of labile, intracellular products has been assessed.