Perfusion and batch-fed systems
Perfusion bioreactors appear to be positioned to become the next major revolution in bioprocessing and single-use equipment,
with perfusion equipment on track to compete head-to-head with conventional batch-fed bioreactors even at commercial GMP scale.
The study, however, showed that the industry's view of perfusion largely is dated.
Perfusion is not new. For example, perfusion bioreactors were widely used for hybridoma culture in the 1970s–1980s before
antibody manufacture switched to batch-fed, mammalian-cell bioreactor manufacture of recombinant antibodies. Perfusion bioreactors
were available from such companies as Endotronics, Cellex, Biosyn, and Biovest. Today, providers of perfusion bioreactors
include FiberCell Systems and Zellwerk (marketed in the US by Glen Mills).
Nearly all current bioprocessing today involves batch-fed bioreactors. Perfusion involves continuous slow feeding and removal
of spent media along with the desired product with the host cells retained within the bioreactor by being bound to bundles
of capillary fibers or other membranes or retained in suspension in the bioreactor by special filters. While batch-fed bioreactors
involve cells in dilute culture- media suspension, perfusion bioreactors grow cells at ≥100 to 1000 × times higher concentration,
with bioreactors commensurately smaller. Thus, using a small perfusion bioreactor over time with the same amount of culture
media may match or beat the product output of a much larger batch-fed bioreactor. For example, FiberCell Systems reports it
is developing desk-sized units that will have the equivalent recombinant-protein production capacity of conventional 2000–5000-L
bioreactors. Also, ATMI recently launched iCellis, the first large-scale perfusion bioreactor.
Although perfusion appears to be a viable new product candidate, the BioPlan survey shows that industry knowledge and attitudes
toward perfusion remain largely dated. Among a list of 17 problems commonly encountered in bioprocessing, respondents consistently
had more serious concerns with perfusion than with batch-fed systems. These issues included process complexity (66.1% of respondents
had serious concerns with perfusion systems compared with 4.9% for batch-fed) and contamination risks (63.9% had concerns
with perfusion compared with 3.8% for batch-fed systems) (1). These and other concerns for perfusion already are being resolved
as new bioreactors enter the market. As new products are launched in coming years, commercial-scale devices are likely to
capture significant interest as new upstream solutions.
Eric Langer is president of BioPlan Associates, tel. 301.921.5979, email@example.com
, and a periodic contributor to Outsourcing Outlook.
1. E.A. Langer, 8th Annual Report and Survey of Biopharmaceutical Manufacturing Capacity and Production, BioPlan Associates (Rockville, MD, April 2011),