What is high cell density?

High-cell-density cultivation (HCDC) is required to improve microbial biomass and product formation substantially. An overview of HCDC is given for microorganisms including bacteria, archae and eukarya (yeasts). Problems encountered by HCDC and their possible solutions are discussed.

How do you increase cell density?

One approach to increase protein yield is to increase the total number of cells. In order to increase the number of cells, large bioreactors up to 25,000 liters would be used. A second approach is to increase the number of cells in the same volume, effectively increasing viable cell density.

How do you describe cell density?

Cell density refers to the number of cells per unit volume. Often cell density is denoted as viable cell density which is the number of living cells per unit volume.

Why is cell density important?

Cell density shows very little variation within a given cell type. This tight control indicates that maintenance of a cell type-specific cell density is important for cell function. Indeed, pathological conditions such as cellular senescence are accompanied by changes in cell density.

What is high density culture?

High density cell culture systems offer the advantage of production of bio-pharmaceuticals in compact bioreactors with high volumetric production rates; however, these systems are difficult to design and operate. First of all, the cells have to be retained in the bioreactor by physical means during perfusion.

How is cell density controlled?

Genetic, biochemical, and cell mosaic studies demonstrate that cells coordinate their multicellular behavior by transmission of intercellular signals. In turn, proper signaling insures that the appropriate cell density exists, thus controlling the progress of multicellular development in M.

What is cell seeding density?

The cell seeding density (cells/cm2), i.e. the number of cells in 1 cm2 of growth surface, allows to make the growth and cell proliferation data homogeneous and independent from the growth vessel used, while the total number of cells depends on the surface on which the cells are grown (trivially the greater the surface …

How large is a cell?

At 0.1 to 5.0 μm in diameter, prokaryotic cells are significantly smaller than eukaryotic cells, which have diameters ranging from 10 to 100 μm. The small size of prokaryotes allows ions and organic molecules that enter them to quickly diffuse to other parts of the cell.

What is density with example?

Density is a measure of how compact the mass in a substance or object is. The density of an object or substance can be calculated from this equation: density in kilograms per meter cubed is equal to mass in kilograms, divided by volume in meters cubed. Examples of dense materials include iron, lead, or platinum.

What is apoptosis in cells?

If cells are no longer needed, they commit suicide by activating an intracellular death program. This process is therefore called programmed cell death, although it is more commonly called apoptosis (from a Greek word meaning “falling off,” as leaves from a tree).

Which is the correct definition of cell density?

Cell density refers to the number of cells per unit volume. Often cell density is denoted as viable cell density which is the number of living cells per unit volume.

What does high cell density mean in fermentation?

From: Lee SY, High cell-density culture of Escherichia coli [J], Trends in Biotechnology, 1996 March: 14 (3):98-105. Industrial fermentation is the intentional use of fermentation by microorganisms such as bacteria and fungi to make products useful to humans.

How are cell mass and productivity maximized in high cell density cultures?

In fed-batch cultures, cell mass and productivity are maximized by adjusting culture conditions, including temperature and pH, the composition of the feed media, and the substrate feed rate. As one of the most critical factors to the success of high cell density culture, various nutrient feeding strategies have been developed.

How is the density of a material defined?

The density of a material is defined as its mass per unit volume: Rho = m/V. Different materials usually have different densities, so density is an important concept regarding buoyancy, metal purity and packaging. Cell density refers to the number of cells per unit volume.