title = 'oxygen transfer correlation in high cell density culture of recombinant e. coli', abstract = 'a recombinant e. coli bl21 pet3a-t2m2 was cultivated in fed-batch cultures and cell mass increased to more than 70g/l.
the stock consistency in the dilution zone varies by mill, yet the typical range is 3.0-6.0 %bd consistency. lightnin's standard offer for agitation in this application is the vsa pillowblock agitator. for more information on high density storage, contact your local area sales representative and/or refer to the following reference information:
a viable cell density vcd of 40 x 106 cells/ml with high viability >96.8% was achieved and maintained for 13 days during the cell culture run figure 1 . perfusion was initiated on day 3 at 1 vvd volume of media per bioreactor volume per day and increased to 2 vvd on day 5. is the bioreactor volume.
on-line optical cell density probes, based on light backscatter have been used successfully to monitor cell cultures. 90 such measurements are generally linear with cell concentration only at high viabilities, and deviate significantly from linearity with decreasing culture viability, which commonly occur in the latter stages of fed-batch cultures.
3 pfu/cell would give higher cell-specic yield data not shown . any combination of cell density and moi that resulted in an overall cell density above 2 2.5 million cells/ml during aav production re-
high-density cultures 21.7 ± 1.8 × 10 6 cells/ml in the 3 l and 200 l bioreactors were evaluated to demonstrate the pco 2 difference from different bioreactor scales and sparger configurations, and the potential impact of that on culture ph.
the cells in perfusion mode, which ensures a consistent supply of nutrients and the removal of toxic byproducts. we achieved the very high vero cell density of approximately 43 million cells per ml, demonstrating great potential for vero-cell-based vaccine production using fibra-cel packed-bed vessels. introduction
high cell density and different studies have considered different values of dry cell weight like 50 g/l shokri and larsson, 2004; rozkov, 2001 and even values in ized bioreactor, high mechanical load on the agitation system and sensing and probing limitations should also be considered shiloach and fass, 2005 .
limitations of microcarriers in high density cell culture for a significant length of time, microcarriers have been used for high density cell culture. these microcarriers are added into stirred tank bioreactors and then adherent cells bound into them to grow and proliferate.
previous efforts have shown that high-density hd cell banking can be an effective means to reduce the number of seed-train steps required and also improve operational success in seed-train processes. tao et al. reported using hd cell banks containing 450 million viable cells/vial to directly inoculate a 20-l wave bag 2 . that study revealed that hd cell-bank use could eliminate several intermediate shake-flask expansion steps and reduce process times by up to nine days.
high cell density fed-batch cultivation of escherichia coli using exponential feeding combined with ph-stat. a new feeding strategy in fed-batch culture. exponential feeding combined with ph-stat is suggested to avoid the accumulation of substrate in culture broth.
achievement of a cell density up to 50 × 10 6 cells/ml is reported in the literature using perfusion based on hollow fiber device. 5 kyung et al. 31 have shown that high cell density of 10 8 hek293 cells/ml in suspension could be achieved using an internal hollow fiber module with cellulose ester membrane.
in high density perfusion reactors, variable cell density, and hence the metabolic demand, require constant adjustment of perfusion rates. the use of cell specific perfusion rate cspr control provides a constant environment to the cells resulting in consistent production.
in this experi- ment, the apparent viscosity of the culture broth of c. roseus increased with cell growth and exhibited 510 c.p at a high cell density of 19 g dry weight per liter. in contrast, a high cell density culture of about 30 g dry weight per liter was not as viscous as in the case of o. sativa cells about 10c.p .
high-density cell bank 4.5 ml, 50 to 100 × 106 cells/ml perfusion mode 1 to 10 l up to 2000 l batch mode high-cell density perfusion cultures 2 l addition of cryopreservation medium 1:1 culture expansion in perfusion mode 10 l test revival shake flasks aliquotation 4.5 ml medium reduction 2 l 2 ab a b fig 1.
scale up of high cell density process to large-scale bioreactors by providing sufficient oxygen supply and co 2 removal can be challenging in some cases, and requires proper selection of large-scale bioreactor operating parameters. 76 bioreactor operating parameters can be categorized into volume-dependent parameters, e.g., working volume, feed volume, agitation, aeration and volume-independent parameters, e.g., ph, dissolved oxygen, temperature. a general strategy for scale-up is to
suzuki 1996 obtained a high cell dry weight of 141 g/l by using ceramic filters, and the production rate was approximately 0.8 g/l/h. srivastava et al. 1992 described an ion exchange resin extraction-type lactic acid fermentation, with a cell density of 30 g/l. although,
the high cell density fermentation by fed-batch strategies is one of the most cost-effective means of achieving high yields for the production of heterologous proteins, which is widely used in the bio-industry. in fed-batch cultures, cell mass and productivity are maximized by controlling culture conditions such as the temperature and ph, the composition of the feed media, and the substrate feed rate.
high-density cell bank 4.5 ml, 50 to 100 × 106 cells/ml perfusion mode 1 to 10 l up to 2000 l batch mode high-cell density perfusion cultures 2 l addition of cryopreservation medium 1:1 culture expansion in perfusion mode 10 l test revival shake flasks aliquotation 4.5 ml medium reduction 2 l 2 aa a b fig 1.