The Three SUB Architectures at a Glance
Single-use bioreactors (SUBs) eliminate CIP/SIP validation, reduce turnaround time by 4–8 hours per batch, and lower cross-contamination risk. As of 2026, three distinct architectures dominate the market: wave (rocking motion), stirred-tank, and fixed-bed systems. Each serves fundamentally different bioprocess needs.
Single-use bioreactor is any cultivation vessel in which the product-contact surfaces — bag, tubing, sensors, and filters — are discarded after a single batch. The reusable component is the controller and housing; the disposable component is the pre-sterilised (gamma-irradiated) bag assembly or cartridge.
The global single-use bioreactor market reached approximately $4.3 billion in 2025 and is projected to grow at ~9% CAGR through 2035. Stirred-tank systems account for roughly 57% of installed units, followed by wave/rocking at 9% and fixed-bed at 6%, with the remainder split across orbital shaken, air-lift, and hybrid designs.
Wave (Rocking Motion) Bioreactors
Wave bioreactors mix and aerate cell culture by rocking a pre-sterilised cellbag on a motorised platform, creating a wave motion across the liquid surface. Because there is no impeller or sparger, shear stress is extremely low — typically 0.1–1.0 Pa compared to 1–10 Pa in stirred-tank systems.
The main commercial platforms include the Sartorius BIOSTAT RM (formerly GE WAVE), the Cytiva ReadyToProcess WAVE 25, and the Eppendorf BioBLU Rocking. Working volumes range from 0.1 L up to approximately 200 L (Sartorius BIOSTAT RM 200), though most installations operate at 2–50 L.
Oxygen transfer occurs solely through the gas–liquid interface at the wave surface. This limits kLa to approximately 2–12 h−1, which can become restrictive above 5 × 106 cells/mL when air alone is used. Supplementing with oxygen-enriched gas extends the viable cell density ceiling but does not fundamentally change the mass-transfer mechanism.
Best applications for wave bioreactors
- Perfusion seed train — N−1 perfusion in a 25–50 L wave bag with integrated cell retention device (hollow fibre or floating filter) to generate high-density inocula for production bioreactors
- Shear-sensitive cells — primary T cells for CAR-T manufacturing, iPSCs, mesenchymal stem cells, endothelial cells
- Process development screening — early-stage clone evaluation and media optimisation at 1–10 L with minimal CapEx
- Viral seed stock production — low-volume, high-value viral seed stocks where gentle conditions preserve infectivity
| Platform | Max Working Volume | kLa Range (h−1) | Rocking Rate | Perfusion Capable |
|---|---|---|---|---|
| Sartorius BIOSTAT RM 200 | 200 L | 2–10 | 5–42 rpm | Yes (with retention device) |
| Cytiva ReadyToProcess WAVE 25 | 25 L | 4–12 | 6–40 rpm | Yes |
| Eppendorf BioBLU Rocking | 25 L | 3–8 | 5–35 rpm | Yes |
Single-Use Stirred-Tank Bioreactors
Single-use stirred-tank bioreactors (SU-STRs) are the workhorses of commercial biomanufacturing, accounting for approximately 57% of all SUB installations. They combine the proven mixing and oxygen-transfer performance of conventional stainless-steel stirred tanks with the operational simplicity of disposable product-contact surfaces.
A typical SU-STR consists of a pre-sterilised polyethylene bag fitted inside a rigid stainless-steel or plastic vessel. The bag contains a magnetically or bottom-driven impeller, a sparger (ring or microsparger), pH and DO sensor ports, and sampling lines. The rigid vessel provides mechanical support, temperature control (via jacket), and the drive coupling for the impeller.
Key commercial SU-STR platforms
| Platform | Vendor | Max Working Volume | Impeller Type | kLa (h−1) |
|---|---|---|---|---|
| Xcellerex XDR | Cytiva | 2,000 L | Pitched-blade, bottom-mount | 5–25 |
| BIOSTAT STR | Sartorius | 2,000 L | 3-blade segment, top-driven | 5–30 |
| Allegro STR | Pall/Cytiva | 2,000 L | Elephant-ear, bottom-mount | 10–40 |
| HyPerforma S.U.B. | Thermo Fisher | 2,000 L | Pitched blade, bottom-mount | 5–20 |
| HyPerforma DynaDrive | Thermo Fisher | 5,000 L | DynaDrive, bottom-mount | 8–35 |
| Mobius CellReady | MilliporeSigma | 200 L | Marine blade, bottom-mount | 5–15 |
SU-STRs achieve kLa values of 5–40 h−1 depending on sparger type, gas flow rate, and agitation speed. With a microsparger (15–50 µm pores), the Allegro STR reaches up to 40 h−1 at 2,000 L — comparable to stainless-steel vessels of similar volume. This makes SU-STRs suitable for high-density CHO cultures routinely exceeding 20–30 × 106 cells/mL.
Scalability is the defining advantage. Constant geometry parameters (H/D ratio, impeller D/T ratio, number of impellers) enable design-space transfer from 50 L bench scale to 2,000 L production using established criteria like constant P/V or constant tip speed. The largest SU-STR currently available — the Thermo Fisher HyPerforma DynaDrive — reaches 5,000 L working volume.
Scale-Up Calculator
Compare P/V, tip speed, kLa, and Re across source and target vessels. Covers five scale-up criteria side by side.
Fixed-Bed Bioreactors
Fixed-bed bioreactors immobilise adherent cells on a packed scaffold — typically non-woven polyethylene terephthalate (PET) fibres — inside a disposable cartridge. Media is recirculated vertically through the bed, delivering nutrients convectively while an external oxygenation loop (falling-film or sparger) supplies dissolved oxygen.
The dominant commercial platform is the Cytiva iCELLis system (originally Pall/ATMI). The iCELLis Nano provides 0.5–4 m² for process development, while the iCELLis 500+ scales to 66–500 m² in a stainless-steel housing with single-use flow paths. A 500 m² fixed bed is equivalent to approximately 2,940 roller bottles (1,700 cm² each) or 794 ten-tray CellSTACK systems.
Other fixed-bed platforms include the Univercells scale-X (0.075–600 m²) and the Eppendorf BioBLU packed-bed vessels. All share the core advantage: they eliminate the bead-to-bead transfer challenge of microcarrier suspension culture while maintaining single-use convenience.
Best applications for fixed-bed bioreactors
- Viral vector production — AAV, adenovirus, and lentiviral vector manufacturing in adherent HEK293 or A549 cells. The iCELLis has achieved up to 4.5 × 108 vg/cm² for AAV in A549 packaging cells.
- Vaccine manufacturing — Vero cell-based viral vaccines (influenza, rabies, polio) replacing roller bottles and cell factories
- Gene therapy — clinical and commercial-scale adherent cell culture without microcarrier handling
Worked Example — Replacing Roller Bottles with iCELLis
Current process: 1,000 roller bottles × 1,700 cm² = 1.7 × 106 cm² = 170 m² total surface area
iCELLis 500+ equivalent: Select the 200 m² cartridge (bed height 10 cm, 2-fold compaction)
Labour reduction: From ~40 operator-hours per batch (feeding and harvesting 1,000 bottles) to ~4 hours (single bioreactor run)
Footprint reduction: From 20–30 m² of incubator space to a single 2 m × 2 m skid
Surface area match: 200 m² / 170 m² = 1.18× — provides 18% headroom for process variability
Oxygen Transfer (kLa) Comparison
Oxygen transfer capacity is often the deciding factor between SUB types. SU-STRs deliver the highest kLa values (5–40 h−1) through direct sparging, while wave bioreactors rely on surface aeration alone (2–12 h−1). Fixed-bed systems achieve intermediate effective kLa (3–15 h−1) through external oxygenation loops.
For context, a CHO cell culture at 20 × 106 cells/mL with a specific oxygen uptake rate (qO2) of 0.3 × 10−9 mmol/cell/h has an OUR of approximately 6 mmol/L/h. With a maximum DO driving force of ~0.2 mmol/L (air-saturated medium at 37°C), the required kLa to meet this demand is OUR / ΔC* = 6 / 0.2 = 30 h−1. Only SU-STRs with microspargers routinely reach this threshold without oxygen enrichment.
Cost per Batch Analysis
Consumable cost per batch is the primary ongoing expense for single-use systems. The bag assembly (including tubing, sensors, filters, and sparger) accounts for 60–80% of the per-batch disposable spend, with the remainder from process sensors, sampling bags, and transfer lines.
| Volume / Scale | Wave (Bag Assembly) | SU-STR (Bag Assembly) | Fixed-Bed (Cartridge) |
|---|---|---|---|
| 50 L | $500–$1,500 | $800–$2,000 | $2,000–$4,000 (0.5 m²) |
| 200 L | $1,500–$3,500 | $3,000–$6,000 | $4,000–$7,000 (4 m²) |
| 500 L | $3,000–$5,000 | $5,000–$12,000 | $6,000–$10,000 (66 m²) |
| 1,000 L | N/A | $10,000–$25,000 | $8,000–$12,000 (200 m²) |
| 2,000 L | N/A | $15,000–$40,000 | $10,000–$15,000 (500 m²) |
At production scale, stainless-steel vessels become more economical above approximately 30 batches per year for a 2,000 L system, when the amortised CapEx plus CIP/SIP chemicals is lower than the cumulative bag cost. However, single-use systems avoid the $10–40 million facility CapEx for stainless-steel infrastructure, making them the default for CDMOs, clinical manufacturing, and multi-product facilities.
Fermentation Economics Calculator
Model upstream and downstream COGS per gram. Compare batch vs. fed-batch vs. continuous manufacturing modes.
Decision Framework: Choosing the Right SUB
The optimal single-use bioreactor depends on five factors: cell type (suspension vs. adherent), oxygen demand, target scale, shear sensitivity, and operating mode (batch, fed-batch, or perfusion). No single platform excels at everything.
Application-specific recommendations
| Application | Recommended SUB | Typical Scale | Key Reason |
|---|---|---|---|
| mAb fed-batch (CHO) | SU-STR | 200–2,000 L | High kLa, scalability, industry standard |
| AAV vector (adherent HEK293) | Fixed-bed | 66–500 m² | Replaces roller bottles, linear scalability |
| CAR-T manufacturing | Wave | 1–20 L | Low shear, closed system, small batch size |
| N−1 perfusion seed | Wave + retention | 5–50 L | High-density inoculum, simple perfusion setup |
| mAb perfusion production | SU-STR + ATF/TFF | 500–2,000 L | Sustained high VCD, good mass transfer |
| Viral vaccine (Vero, MDCK) | Fixed-bed or SU-STR + microcarriers | 200–500 m² or 50–200 L | Adherent cell support, scalable harvest |
| iPSC expansion | Wave | 0.5–10 L | Ultra-low shear preserves pluripotency |
| Process development | Wave or small SU-STR | 1–15 L | Low CapEx, rapid turnaround, easy operation |
Perfusion Calculator
Model perfusion bioreactor performance: cell retention, bleed rate, dilution rate, and steady-state VCD predictions.
Frequently Asked Questions
What is the maximum working volume for single-use bioreactors?
Single-use stirred-tank bioreactors are available up to 4,000–6,000 L (e.g., Thermo Fisher HyPerforma DynaDrive). Wave/rocking bioreactors max out at approximately 200 L working volume (Sartorius BIOSTAT RM 200). Fixed-bed systems like the Cytiva iCELLis 500+ provide up to 500 m² surface area, roughly equivalent to a 380 L microcarrier suspension in cell capacity.
Which single-use bioreactor type has the best oxygen transfer?
Single-use stirred-tank bioreactors (SU-STRs) deliver the highest kLa values, typically 5–40 h−1 depending on scale and sparger type. Wave bioreactors achieve 2–12 h−1 via surface aeration. Fixed-bed bioreactors use recirculating media oxygenated externally, achieving effective kLa of 3–15 h−1 through falling-film or external sparging.
Are single-use bioreactors suitable for microbial fermentation?
Standard single-use bioreactors are designed primarily for mammalian and insect cell culture. Most SU-STRs cannot reach the high agitation speeds (>500 RPM) and kLa values (>100 h−1) required for high-OUR microbial hosts like E. coli or Pichia. However, some newer systems such as the Thermo Fisher S.U.B. with high-flow spargers or specialised microbial SUBs can support moderate-density microbial cultures up to 20–30 g/L DCW.
How much does a single-use bioreactor bag cost per batch?
Single-use bag assemblies range from approximately $500–$2,000 for 50 L scale, $3,000–$8,000 for 200–500 L, and $15,000–$40,000 for 1,000–2,000 L production scale. Fixed-bed bioreactor cartridges (e.g., iCELLis) cost $5,000–$15,000 depending on surface area. These costs include the bag, tubing, sensors, and filters but exclude media and other consumables.
When should I choose a wave bioreactor over a stirred-tank SUB?
Choose a wave/rocking bioreactor when working with shear-sensitive cells (primary T cells, stem cells, endothelial cells), for perfusion seed train intensification at volumes up to 25–50 L, or for process development screening where low-shear conditions matter. Wave bioreactors also offer a smaller footprint per unit volume at bench scale and require less capital investment than SU-STR systems.
Related Tools
- Scale-Up Calculator — Compare five scale-up criteria side-by-side for stirred-tank bioreactors
- Perfusion Calculator — Model cell retention, bleed rate, and steady-state VCD for perfusion processes
- Fermentation Economics Calculator — Estimate COGS per gram for upstream and downstream processing
References
- Löffelholz, C., Kaiser, S.C., Kraume, M., Eibl, R. & Eibl, D. (2013). Dynamic single-use bioreactors used in modern liter- and m³-scale biotechnological processes: engineering characteristics and scaling up. Advances in Biochemical Engineering/Biotechnology, 138, 1–44. doi: 10.1007/10_2013_187
- Lennaertz, A., Knowles, S., Drugmand, J.-C. & Castillo, J. (2013). Viral vector production in the integrity® iCELLis® single-use fixed-bed bioreactor, from bench-scale to industrial scale. BMC Proceedings, 7(Suppl 6), P59. doi: 10.1186/1753-6561-7-S6-P59
- Dutta, D. et al. (2024). Bioprocess strategies for enhanced performance in single-use bioreactors for biomolecule synthesis: a biokinetic approach. Food Bioengineering, 3(4), e12104. doi: 10.1002/fbe2.12104
- Odeleye, A.O.O., Lye, G.J. & Micheletti, M. (2013). Engineering characterisation of single-use bioreactor technology for mammalian cell culture applications. BMC Proceedings, 7(Suppl 6), P91. doi: 10.1186/1753-6561-7-S6-P91