High cell-density culture of Escherichia coli

Whereas cell concentrations of 5-10 grams dry cell weight per liter (gDCW/l) are typical of batch cultures, fed-batch techniques can be used to achieve concentrations greater than 50 gDCW/l. Feeding strategies for fed-batch cultures include feed-back control as well as pre-determined feeding profiles. The volumetric yield of recombinant products can be improved by controlling the specific growth rate and the substrate concentration. Furthermore, inhibitory by-product formation can be minimized in fed-batch cultures. This review focuses on the use of fed-batch techniques to produce recombinant products in Escherichia coli. The modes of nutrient feeding that have been employed are discussed, and the factors important in attaining high cell concentrations as well as high specific yields of recombinant product are described.

Recombinant Protein Expression in High Cell Density Fed-Batch Cultures of Escherichia Coli

Biological reaction calorimetry: development of high sensitivity bio-calorimeters

Large-scale calorimetry and biotechnology

A review, with 83 refs., showing the application of the fundamentals of thermodn. to biochem. engineering. [on SciFinder (R)]

Quantitative calorimetry and biochemical engineering

Measurements of the heat produced by Saccharomyces cerevisiae CBS 426 were used in conjunction with elemental and enthalpic balances to control fed-batch fermentations. A proportional control using the ratio of carbon dioxide evolution rate to heat production resulted in high biomass yields and minimal ethanol production. For the special case where the carbon source contains no nitrogen, biomass production estimated from heat measurements agreed well with measured values. When the controller gain was set below the maximum specific cellular growth rate, stable control was achieved, even in response to large upsets in feed concentrations.

D. E. Martens

Papers

Calorimetric control of fed-batch fermentations.