Biomedical Engineering Reference
In-Depth Information
43.
J Struct Funct Genomics
. 2006
Jun;7(2):101-8. Epub 2006 Dec
23. Economical parallel protein
expression screening and
scale-up in
Escherichia coli
.
Brodsky O, Cronin CN.
Department of Structural
Biology, Pfizer Global Research
and Development, 10628 Science
Center Drive, La Jolla, CA 92121.
A novel microfermentation and scale-up platform for
parallel protein production in
Escherichia coli
is
described. The vertical shaker device Vertiga, which
generates low-volume high density (A(600)
approximately 20)
Escherichia coli
cultures in
96-position deep-well plates without auxiliary
oxygen supplementation, has been coupled to a new
disposable shake flask design, the Ultra Yield flask,
that allows for equally high cell culture densities to
be obtained. The Ultra Yield flask, which
accommodates up to 1 l in culture volume, has a
baffled base and a more vertical wall construction
compared to traditional shake flask designs.
Experimental data is presented demonstrating that
the Ultra Yield flask generates, on average, an
equivalent amount of recombinant protein per unit
cell culture density as do traditional shake flask
designs but at a substantially greater amount per
unit volume. The combination of Vertiga and the
Ultra Yield flask provides a convenient and scalable
low-cost solution to parallel protein production in
Escherichia coli
.
44.
Appl Microbiol Biotechnol
. 2007
Feb; 74(2):324-30. Epub 2006
Nov 30. Study of the oxygen
transfer in a disposable flexible
bioreactor with surface aeration
in vibrated medium. Kilani J,
Lebeault JM. Laboratoire Génie
des Procédés Industriels UMR
CNRS 6067, Département Génie
Chimique, Université de
Technologie de Compiègne,
Centre de Recherche de
Royallieu, B. P 20529, 60205,
Compiègne Cedex, France.
The oxygen mass transfer is a critical design
parameter for most bioreactors. It can be described
and analyzed by means of the volumetric mass
transfer coefficient K
L
a. This coefficient is affected by
many factors such as geometrical and operational
characteristics of the vessels, type, media
composition, rheology, and microorganism's
morphology and concentration. In this study, we aim
to develop and characterize a new culture system
based on the surface aeration of a flexible, single-
used bioreactor fixed on a vibrating table. In this
context, the K(L)a was evaluated using a large
domain of operating variables such as vibration
frequency of the table, overpressure inside the
pouch, and viscosity of the liquid. A novel method
for K(L)a determination based on the equilibrium
state between oxygen uptake rate and oxygen
transfer rate of the system at given conditions was
also developed using resting cells of baker's fresh
yeast with a measured oxygen uptake rate of 21 mg
g(-1) h(-1) (at 30°C). The effect of the vibration
frequency on the oxygen transfer performance was
studied for frequencies ranging from 15 to 30 Hz,
and a maximal K(L)a of 80 h(-1) was recorded at 30
Hz. A rheological study of the medium added with
carboxymethylcellulose at different concentrations
and the effect of the liquid viscosity on K(L)a were
determined. Finally, the mixing time of the system
was also measured using the pH method.
