The main bioreactor types are stirred-tank (the workhorse of cell culture), single-use/disposable, airlift, packed-bed, and wave/rocking systems – each suited to different scales and processes. Paul Industries installs bioreactors and the WFI, clean steam, and sanitary piping utilities they run on.
Common bioreactor types
| Type | Typical use |
|---|---|
| Stirred-tank (STR) | The standard for microbial and mammalian cell culture at most scales |
| Single-use / disposable | Faster changeover, no CIP/SIP between batches; clinical and flexible manufacturing |
| Airlift | Low-shear mixing via gas sparging; shear-sensitive cultures |
| Packed-bed / fixed-bed | Adherent cells on a matrix; cell and gene therapy |
| Wave / rocking | Small-to-mid single-use culture, seed trains |
Bioreactors and their utilities
Whatever the type, a bioreactor depends on clean utilities – WFI, clean steam for SIP (on stainless systems), sanitary piping, and controls. Single-use systems reduce cleaning but still need supporting infrastructure. Paul Industries builds and integrates that infrastructure.
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Perfusion vs fed batch: what the vessel has to do differently
Type selection is usually discussed as a choice of vessel geometry, but the operating mode decides more of the hardware than the geometry does. Fed batch grows a culture in one charge, feeds it, and harvests once. Perfusion holds cell density steady by continuously removing spent medium through a cell retention device and replacing it, running the same vessel for weeks.
The hardware consequences separate quickly. A perfusion vessel is smaller for a given output, because productivity comes from density and run length rather than from volume. It needs a retention device, tangential flow filtration or an acoustic or centrifugal separator, and that device is a consumable with its own fouling behaviour. It needs medium feed and permeate removal running continuously, which means two more pump loops, two more balances or flow meters, and a control strategy that holds the bleed rate against a density measurement rather than against a clock.
Fed batch puts the burden elsewhere: larger working volume for the same output, a larger jacket and heat removal duty, larger seed train, and a harvest step sized to move the whole batch at once. Sterility risk is concentrated into a short window. In perfusion it is spread across a long campaign, so every connection made during the run has to be genuinely closed.
The practical rule is that perfusion trades vessel size for connection count and control complexity. A plant that cannot maintain a closed transfer for six weeks should not choose it because the vessel looked cheaper.
What the type choice does to installed cost
Choosing single use over stainless moves cost from capital into consumables, and the published figures show how far. Our cost guide records a single use bioreactor at 2,000 L priced at over $2,000,000 at the largest single use scale commonly offered, and comparative analyses placing single use skids at 50 to 66 percent lower upfront capital than a stainless equivalent.
That upfront advantage reverses over a long enough campaign, because a consumable bag and its assemblies are bought again every run while a stainless vessel is cleaned. Where the crossover sits depends on batch frequency, scale and product life, which is why there is no universal answer to the question. The figures above and the facility level comparison behind them are on our bioreactor cost guide. One constraint is worth naming with them: microbial culture in single use is limited near 1,000 L by heat transfer, so above that scale the comparison stops being a free choice.
What to require when you specify a bioreactor type
A specification that names only a type and a volume leaves the decisions that matter open. Fix these before a vendor list is drawn up.
- Cell line and culture mode, since mammalian suspension, microbial fermentation and adherent culture point at different vessel families before any vendor is involved.
- Working volume and total volume stated separately, together with the minimum working volume the vessel must control at, which decides seed train design.
- Oxygen transfer requirement expressed as a target rather than an impeller description, so vendors compete on delivering it.
- Maximum shear tolerance of the culture, stated explicitly, because it is the constraint that rules out otherwise suitable configurations.
- Heat removal duty at peak metabolic rate, with the cooling medium and its supply temperature named.
- Gassing strategy: sparger type, gas species, mass flow ranges and whether overlay is independently controlled.
- Turndown ratio required across the campaign, since a vessel that cannot control at low volume forces an extra seed step.
- For single use, the bag film and its extractables and leachables documentation, plus a named second supplier or a written acceptance of single sourcing.
- For stainless, the cleaning and sterilization route: spray device coverage, drainability, and whether SIP is by plant steam connection or a dedicated generator.
- Scale up intent, including which parameter is held constant on transfer to the next scale, because that decision constrains geometry at every scale.
Frequently asked questions
What is the difference between stainless steel and single-use bioreactors?
Stainless bioreactors are permanent, cleaned and sterilized in place via CIP/SIP, and favored at large scale and high batch frequency. Single-use bioreactors use pre-sterilized disposable bags, cutting cleaning, cross-contamination risk and changeover time, and suit multi-product or smaller-scale operations. The choice balances capital against consumable cost.
What is a stirred-tank bioreactor?
A stirred-tank bioreactor is the most common design, a jacketed vessel with one or more impellers that mix media, distribute gas and control temperature. It handles microbial and mammalian cultures across scales. Impeller type and speed are matched to the cells’ shear tolerance and oxygen demand.
What is an airlift bioreactor?
An airlift bioreactor circulates and mixes culture using injected gas rather than a mechanical impeller, creating flow between a riser and downcomer. With no stirrer, it delivers gentle, low-shear mixing suited to shear-sensitive cells, though oxygen transfer and mixing control are less flexible than stirred tanks.
When would you choose a wave or rocking bioreactor?
Wave or rocking bioreactors mix a single-use bag on a rocking platform, giving very low shear and simple operation. They suit seed-train expansion, small-to-mid mammalian and stem-cell cultures, and rapid product changeover. They do not scale as large as stirred tanks but excel at flexible, low-volume work.
What is a packed-bed bioreactor used for?
A packed-bed bioreactor immobilizes cells on a fixed matrix while media perfuses through, achieving high cell density with low shear. It suits adherent cell cultures and some perfusion processes. The trade-off is more complex scale-up and monitoring compared with suspension stirred-tank systems.
What is a perfusion bioreactor?
A perfusion bioreactor continuously feeds fresh media and removes spent media while retaining cells, sustaining high viable-cell density and prolonged production. It contrasts with batch and fed-batch modes. Perfusion needs a cell-retention device and tighter process control but boosts productivity per volume.
What is the difference between batch, fed-batch and continuous bioreactors?
Batch runs a fixed charge to completion. Fed-batch adds nutrients over time to extend growth and yield, the most common biopharma mode. Continuous, including perfusion, feeds and harvests steadily for extended runs. Mode selection depends on product stability, titer goals and regulatory strategy.
What is a photobioreactor?
A photobioreactor cultivates photosynthetic organisms such as algae and cyanobacteria using controlled light alongside gas exchange and mixing. Designs include tubular, flat-panel and column formats. They serve biofuel, nutraceutical and specialty-chemical production where light delivery, not just aeration, drives growth.
Which bioreactor type suits mammalian cell culture?
Mammalian cells are shear-sensitive, so stirred tanks with low-shear impellers, wave/rocking systems, or perfusion designs are common. Single-use formats dominate at clinical and mid scale for their low cross-contamination risk. The choice depends on cell line, titer target and production scale.
How does scale affect bioreactor type selection?
Small development and seed stages favor benchtop, wave or single-use systems for speed and flexibility. Large commercial production often favors stainless stirred tanks where consumable economics and volume demand it. Single-use currently scales to roughly a couple thousand liters, beyond which stainless typically takes over.
What materials are stainless bioreactors made from?
Stainless bioreactors use 316L stainless steel for product-contact surfaces, typically electropolished to a controlled Ra finish per ASME BPE for cleanability. Jackets may be carbon or stainless steel. Elastomer seals and gaskets are USP-Class-VI compatible. Passivation restores the passive chromium-oxide layer.
What is the difference between microbial and mammalian bioreactors?
Microbial fermentation, bacteria and yeast, demands high oxygen transfer, vigorous agitation and strong cooling for fast, robust cells. Mammalian bioreactors run gentler agitation, lower shear and tighter gas and pH control for fragile cells. Impeller design, aeration and cooling capacity differ accordingly.
Can single-use and stainless bioreactors be mixed in one facility?
Yes, and hybrid facilities are now the common case rather than a compromise. Single-use dominates at smaller working volumes and in multi-product or clinical facilities where changeover speed matters and cleaning validation is the burden you most want to avoid. Stainless earns its place at large commercial volumes where consumable cost would otherwise dominate, and for utilities. The engineering attention belongs at the transitions, where a welded line meets a disposable assembly, because that connection is the hardest part to validate.
What determines the right impeller for a bioreactor?
Impeller choice, Rushton for gas dispersion, marine or pitched-blade for gentle axial flow, balances oxygen transfer against shear. Microbial cultures tolerate high-shear Rushton designs; fragile mammalian cells need low-shear impellers. Number, size and speed are set by the culture’s oxygen demand and shear sensitivity.
How do I choose the right bioreactor type for my process?
Work from the organism and the scale, in that order. Mammalian cell culture needs gentle mixing and careful shear control, which points to stirred tanks with large low-shear impellers or to rocking and wave designs at small scale. Microbial fermentation is robust but oxygen-hungry and generates far more heat, so it needs aggressive agitation, high gas transfer and real cooling capacity. Then scale decides single-use against stainless, since the consumable cost of disposables rises directly with volume and batch count.
What are the main types of bioreactors?
Stirred tank remains the workhorse across both mammalian and microbial work, with an impeller providing mixing and gas dispersion. Airlift and bubble column designs use rising gas rather than mechanical agitation, giving low shear at the cost of control. Wave and rocking bioreactors are single-use systems suited to seed train and small-scale culture. Packed bed and hollow fiber designs support adherent cells. Perfusion is a mode of operation rather than a vessel type and can be applied to several of these.
What is a stirred-tank bioreactor used for?
Most production culture and fermentation, because it gives the best combination of mixing, gas transfer and control across a wide range of scales. An impeller disperses sparged gas and keeps cells and nutrients suspended, while baffles prevent vortexing. The design compromise is shear: the same agitation that improves oxygen transfer damages shear-sensitive mammalian cells, so impeller type, tip speed and sparger design are selected against the organism rather than for maximum mixing.
What is the difference between single-use and stainless bioreactors?
Single-use replaces the cleanable wetted path with a pre-sterilized disposable assembly, so cleaning validation disappears and is replaced by extractables and leachables assessment plus a supply chain dependency. Capital cost is far lower and changeover is fast. Stainless carries higher capital and full CIP and SIP infrastructure, but the consumable cost is near zero, which is why it wins at large volumes and high batch counts. The crossover depends on working volume and annual batches rather than on preference.
Do you install bioreactor utilities?
Yes, and the utilities are usually where bioreactor projects actually run into trouble. A bioreactor needs Water for Injection or Purified Water at a defined flow and temperature, clean steam for sterilization with condensate that clears, process gases, and a CIP supply and return whose demand is frequently larger than the process draw. We define the required flow, temperature and pressure at every connection during design and confirm the existing systems can deliver them simultaneously, rather than discovering it at commissioning.
What is an airlift bioreactor and where is it used?
It circulates culture using injected gas rather than a mechanical impeller, creating a loop between a riser and a downcomer. It suits shear-sensitive cultures and removes the seal and shaft cleaning problems of an agitated vessel, at the cost of less control over mixing.
What is a fixed-bed versus a fluidised-bed arrangement?
In a fixed bed the carrier material stays stationary while medium flows through it. In a fluidised bed the carriers are suspended by the upward flow, which improves mass transfer and mixing at the cost of carrier attrition and a narrower operating window.
What is a hollow fibre bioreactor used for?
It grows cells in the extracapillary space around semi-permeable fibres carrying medium, achieving very high cell density in a small footprint. It is common for producing small volumes of concentrated product rather than for large-scale manufacturing.
What is a wave or rocking bioreactor?
A single-use bag on a rocking platform where the wave motion provides mixing and gas transfer without an impeller. It is widely used for seed train expansion because it is fast to set up and has no cleaning requirement.
How does bioreactor type affect facility design?
Stainless vessels bring clean steam, cleaning circuits and drainage. Single-use brings consumable storage, waste volume and different utility demands. The choice changes the building as much as it changes the equipment.
What is a fed-batch process and how does it differ from batch?
Batch runs to completion on the medium charged at the start. Fed-batch adds nutrient during the run to extend productivity without diluting the culture. Fed-batch needs feed vessels, accurate addition control and the preparation capacity behind them.
Batch bioreactor or fed batch bioreactor: how do the two modes differ?
A batch bioreactor is charged with all its medium at the start, inoculated, and run until the culture exhausts a nutrient or reaches the harvest point; nothing is added except gas and pH agents. A fed batch bioreactor starts the same way but receives controlled feeds of concentrated nutrients during the run, which keeps substrate levels in the optimal window, avoids inhibition from high starting concentrations, and typically reaches several times the cell density and product titer. Most commercial mammalian cell culture today runs fed-batch, with perfusion gaining ground for continuous processes.
Is a fermenter the same as a bioreactor?
In practice the words overlap, but the convention is that a fermenter bioreactor grows microbial cultures (bacteria, yeast or fungi) that tolerate high agitation, high oxygen transfer and fast growth, while a bioreactor for cell culture grows mammalian or insect cells, which are shear-sensitive, grow slowly and need gentler mixing, fine-bubble sparging and tighter control of dissolved CO2. The mechanical design differs accordingly: a microbial fermenter has Rushton turbines, baffles and high-power drives; a cell-culture vessel has pitched-blade or marine impellers, lower tip speeds and often a larger headspace for overlay gassing.
When is a stainless steel bioreactor still the right choice over single-use?
A stainless steel bioreactor makes sense above roughly 2,000 L, where single-use bags are not offered or become unwieldy; for microbial fermentation, where oxygen demand and heat removal exceed what a bag can deliver; for processes with solvents or high-temperature steps that attack bag films; and for long campaigns of the same product, where the consumable cost of bags outweighs the capital and cleaning validation of a fixed vessel. The trade is CIP/SIP infrastructure, cleaning validation and changeover time against bag cost and supply-chain risk.
What are hollow fiber and fixed bed bioreactors used for?
Both hold cells in place while medium flows past them, which suits adherent cells and continuous harvest. A hollow fiber bioreactor grows cells in the space around thousands of semi-permeable fibers, with medium flowing through the fiber lumen, reaching tissue-like cell densities in a small footprint; it is common for antibody production from hybridomas and for cell therapy and exosome work. A fixed bed bioreactor packs a chamber with carriers (polyester strips, macrocarriers or structured sheets) that adherent cells attach to, with medium recirculated through the bed; it is widely used for viral vector and vaccine production where cells need a surface to grow on.
Install or integrate a bioreactor
Paul Industries is a single-source supplier, installer, and validator – one accountable partner from design through documented startup. Tell us about your project and we will scope it.
Which bioreactor type is right for your process?
Choose on scale, product and cleaning strategy. Stirred-tank remains the default for most commercial mammalian and microbial work. Single-use removes cleaning validation and changeover time and suits multi-product and clinical-scale facilities, at the cost of consumables and extractables documentation. Airlift, wave and packed-bed systems solve specific shear or perfusion problems. Paul Industries installs, connects and supports qualification for all of them.