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Processing of proteins using supercritical fluids

Objective



Objectives and content
Supercritical carbon dioxide (scCO2) has many advantages
over conventional liquid solvents, being non-toxic,
cheap, and versatile. Its solvation power can be finely
adjusted with changes in temperature and pressure around
its critical point, at 31.06 . The properties of scCO2
are currently being explored for an array of industrial
processes, including extraction, microparticle formation
and chemical reactions. The low temperature environment
is theoretically ideal for proteins which denature at
high temperatures, but scCO2 is poor at dissolving both
polar and very large molecules. In addition, scCO2 has
been known to cause denaturing of proteins by virtue of
its high acidity when dissolved in water.
Recent work has demonstrated the use of non-toxic
polyfluoropolyether (PFPE) surfactants to stabilise a
microemulsion of an aqueous discrete phase dispersed
within a continuous phase of supercritical carbon
dioxide. The micelles of PFPE have been shown to
effectively solvate the test protein BSA within the
micelles of PFPE. This development is important, as work
on conventional reverse micellar solutions and water-inoil microemulsions for biotechnology has used toxic
surfactants and continuous phase organic solvents which
are unacceptable to the food and pharmaceutical
industries.
This project will develop supercritical fluid
technologies for the processing of proteins and peptides,
using CO2-philic surfactants including PFPE. The
following techniques will be explored;
Cell breaking using rapid pressurisationdepressurisation cycles of scCO2
Protein purification through fine tuning of the solvent
properties of scCO2-water microemulsions
Protein particle formation and encapsulation using
various supercritical fluid techniques
The CO2-philic surfactants will also be evaluated for
speeding the cell breaking process. Work on the
microemulsions is a high-risk area which is balanced by
the more medium technical risk areas of the project. A
particular challenge will be overcoming the high acidity
of the water domains within the micelles.
This project will combine the efforts of academic
institutions, encapsulation and supercritical fluid
extraction specialists, and end users within the enzyme
and pharmaceutical industries. The work will be
supported by state-of-the-art spectroscopic analytical
techniques and protein analysis, and will involve
requirements specification, evaluation of various
surfactants and protein solubilisation experiments,
development of each of the elements described above, and
a final testing programme.
The supercritical fluid technology will be developed with
wide industrial applications in mind, and the end user
partners will be able to use the developed technology
soon after project end to reduce the costs involved in
protein processing, and in the development of new,
encapsulated protein and peptide products.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

SMITHKLINE BEECHAM PLC
Address
New Horizons Court
TW8 9EP Brentford
United Kingdom

Participants (5)

Biocatalysts Ltd.
United Kingdom
Address
Main Avenue
CF37 5UT Pontypridd
INSTITUTO DE BIOLOGIA EXPERIMENTAL E TECNOLOGICA
Portugal
Address
Quinta Do Marques
2780-901 Oeiras
MICROLITHE SA
France
Address
111,Zone Industrielle Athélia Iii, Voie Atlas
13705 Marignane
Separex Chimie Fine SA
France
Address
Rue Jacques Monod
54250 Champigneulles
UNIVERSITY OF NOTTINGHAM
United Kingdom
Address
University Park
Nottingham