In the last issue, we described the characteristics of commercial production, reaction volume, batch run and cell density in perfusion culture, which will be continued in this article.

Schematic diagram of the perfusion culture process (image from the Internet)

high cell density Perfusion is able to maintain high cell densities, e.g. 100e6/ml, during the "steady state" phase, and cell viability is usually maintained above 90%. The expression amount can reach more than 15g/L. (As shown below)

(Pictures from the internet)

}Features of perfusion culture

Homeostatic operation: Can make the medium in the system be renewed continuously to meet the cell's demand for nutrients in time, and at the same time remove harmful metabolites, such as lactate and ammonium, to give the cells a stable and high-quality The system also removes harmful metabolites such as lactic acid and ammonium, providing cells with a stable and high-quality growth environment.

Reduced culture scale: High cell density, high cell viability, and high throughput make it possible to achieve replenishment batch culture mass production output with the size of a small-scale bioreactor, which allows the miniaturization of the culture scale and increases the flexibility of operation.

Improve product quality: The most notable advantage is that the protein products can be separated in time along with the culture medium, and the residence time in the reactor is short, which is less subject to the degradation of the various hydrolytic enzymes in the culture system, and is conducive to the improvement of the protein amount.

Improve yield and reduce cost: Compare with flow-through batch, the production cost is reduced by about 20%.

There are of course some shortcomings in perfusion culture. Perfusion culture consumes a lot of medium and requires specialized equipment, and the risk of bacterial contamination increases with prolonged culture. However, continuous perfusion culture is still one of the most popular methods of mammalian cell culture for the production of secreted recombinant proteins, chimeric antibodies, humanized antibodies and other genetically engineered antibodies in recent years.

(Customer application site)