Alternative culture processes for laboratory scale-up (to 20 L) are described for both suspension and
anchorage-dependent cells. Systems range from simple multiple culture units such as the roller bottle, through
stirred suspension and microcarrier unit bioreactors, to highly sophisticated perfusion culture capable of
maintaining cells at densities of about 108/mL. Critical parameters in scale-up are discussed, and the advantages
and disadvantages of each culture system are critically evaluated.