Table 4.

Comparison of plants cells with mammalian cells, yeasts and bacteria with regard to the characteristics calling for special considerations in bioreactor process development.^†

Characteristics	Plant cells	Mammalian cells	Yeasts	Bacteria
Size	20–50 μm in diameter and 100–500 μm in length	10–50 μm	3–5 μm	<1 μm
Shape	Spherical/cylindrical	Spherical	Spherical to ellipsoidal	Spherical
Cell aggregation	Aggregated to form cell clusters from <100 μm to over 2 mm	Single cells; not aggregated	Single cells; not aggregated	Single cells; not aggregated
Doubling time	20–100 h	24–48 h	2–3 h	30 min to 1 h
Shear sensitivity	High	Extremely high	Low	Low
Oxygen uptake rate	2–10 mmol/l/h	0.05–10 mmol/l/h	10–200 mmol/l/h	10–90 mmol/l/h
Required kLα value in bioreactor operation	10–50/h	0.25–10/h	100–1000/h	100–500/h
Protein localization	Intracellular/secreted	Secreted	Intracellular/secreted	Usually intracellular

k_L^α: Volumetric oxygen transfer coefficient.

Data adapted from [31].