Problems in large scale culture of plnt cells

Large acale culture of plant cells for commercial applications like biochemical, artificail seed etc. Producation presents serveral problems which are summarised below.
1. Plant cells have much slower growth rates than bacteria anf fungi, therfore, larger reactores and longer fermentation times are necessary.
2. The long fermentation time increases the risk contamination.
3. Plant cells are rather sensitive to shear. Therefor, fementers with conventional mechanical stirring are not suitable for their culture. Bioreactors having specially designed mechanical stirrers airlift fermenters are far more suitable.