Voltage, organism, oxygen, automation, and validation: the five questions that will help you choose the right bioreactor or fermenter for your process.
When comparing bioreactor specifications, the most notable figure is usually the nominal volume. However, it is the factor that has the least impact on a project’s success.
A well-chosen system is defined by five factors: how much usable volume you need, what organism you’re growing, how much oxygen your culture requires, what level of control you need, and what validation your industry will require.
At Techmi Group, we manufacture bioreactors and fermenters ranging in size from 0.25 L to 30,000 L. In this article, we address the five questions and highlight which equipment in our lineup meets each one—from the laboratory to the industrial plant.
1. What is your actual workload, and what stage of scaling are you in?
A tank’s nominal volume is not its usable volume. Foam, aeration, and headspace limit how much medium you can load. The Techmi Bio 500 operates between 200 and 400 L; the Techmi Bio 1000, between 800 and 900 L; and solid-state fermenters operate at 30% to 50% fill. Always size based on working volume.
The second part of the question is where you are in the scaling process, because each stage requires a different team:
- Development and laboratory (0.25 to 10 L). The Techmi Bio Lab with a glass tank is the starting point. If you need to compare conditions, the dual-tank version runs two cultures in parallel or separately, and the multi-vessel station allows you to screen strains and optimize media with independent control of each vessel.
- Pilot scale (20, 30, and 50 L). The Techmi Bio Pilot and Techmi Bio Pharma, made of 316L stainless steel, replicate fermentation under conditions similar to those found in industrial settings. This is the first step in a scale-up process.
- Small- to medium-scale production (500 to 1,000 L). These systems can be used both for production and as an intermediate step toward larger volumes. The Bio 1000 is available in a dual-fermenter configuration.
- Producción industrial (hasta 30.000 L). El fermentador industrial Techmi Bio 30.000 L se diseña a medida del proceso.
- Industrial production (up to 30,000 L). The Techmi Bio 30,000 L industrial fermenter is custom-designed for the specific process.
Laboratory → Pilot Plant → Industrial Production
If your process is going to scale up, it’s a good idea to define the entire chain from the start. A fermentation scale-up train incorporates fermenters ranging from 20 to 30,000 L, so that each stage is designed to feed into the next, eliminating the need to redesign between stages. If you’d like to learn more, check out our article “Why Is Choosing the Right Bioreactor Important for the Future of Your Bioprocesses?”
2. What organism are you culturing, and what does it require from the team?
Bacteria, yeast, filamentous fungi, and cells all have different requirements. The viscosity of the broth, sensitivity to shear, and tendency to form foam determine the type of agitation, sealing, and defoaming strategy.
For example, the Techmi Bio Lab is used to culture microorganisms such as Bacillus subtilis, Trichoderma harzianum, Bradyrhizobium japonicum, and Rhizobium phaseoli, which are used in enzymes, bio-inputs, and biofertilizers.
The design decisions that vary depending on the organism are as follows:
- Tank material: Glass with an oval bottom and a water jacket for laboratory use (0.25 to 10 L); 316L stainless steel for capacities of 20 L and above.
- Agitation system. The Bio Lab agitates at speeds ranging from 50 to 2,000 rpm with an accuracy of ±1 rpm. For 20- to 50-liter units, you can choose between a direct top drive or a bottom magnetic coupling, which prevents the shaft from passing through the tank wall—an advantage when the culture is long and the risk of contamination must be minimized.
- Type of fermentation. If your organism grows better on a solid substrate than in a liquid medium, you’ll need a different type of reactor.
For solid-state fermentation, the Techmi Bio Fes FSS is a horizontal stirred-tank fermenter with internal axial and radial flow blades that rotates at speeds between 0 and 22 rpm using a reversible motor. It controls temperature, agitation speed, and humidity; is manufactured from 316L stainless steel; and is available in sizes ranging from 10 to 1,000 L, as well as in custom sizes. It is the ideal choice for the sporulation of Trichoderma, enzymes, probiotics, and biofertilizers on grains, cereal husks, or other agricultural byproducts.
The fundamental question is simple: Is your organism cultured in liquid or on a solid medium? The type of equipment you should look for depends on the answer.
3. How much oxygen does your crop need at peak demand?
Oxygen transfer is the most common bottleneck when an aerobic process is scaled up from the laboratory to the plant. The rate at which you can supply dissolved oxygen to the broth is expressed as follows:
OTR = kLa · (C* – CL)
Where C* is the solubility of oxygen under operating conditions and CL is the concentration of dissolved oxygen in the broth. The coefficient kLa depends on agitation, air flow rate, pressure, tank geometry, and the properties of the medium.
The system should not be designed to meet the crop’s average demand, but rather its peak demand, which typically occurs at the end of the exponential phase or during fed-batch feeding.
When evaluating a bioreactor, check three things:
- Agitation range. Our scale-up systems operate at 50 to 1,000 rpm depending on the tank size, and the Bio Lab reaches 2,000 rpm in the laboratory.
- Operating pressure. In large-scale fermenters, it can be set up to 3 bar, which increases oxygen solubility.
- Dissolved oxygen (DO) control. The scaling trains control it from 0 to 100% with an accuracy of ±0.1%.
Always ask the manufacturer for the maximum OTR or kLa of the equipment under your process conditions, and measure it on a small scale before scaling up. The dual-tank Bio Lab is designed, among other uses, for studies of kinetics, oxygen transfer (kLa), and scaling, so you can obtain baseline data before deciding on the size of the final equipment.
4. What level of automation do you need?
Automation is not just an extra: it determines batch-to-batch reproducibility and the amount of manual labor required for each fermentation. The appropriate level depends on the stage:
- Laboratory. The Bio Lab and the dual-tank Bio Lab feature integrated control of temperature, pH, dissolved oxygen, and agitation, with four peristaltic pumps for dispensing acid, base, defoamer, and medium. They support batch and fed-batch processes, and their color touchscreen records data with traceability. The multi-vessel station adds independent control per vessel and storable process recipes.
- Pilot unit. The 20- to 50-liter units feature a Siemens PLC with a 10-inch touchscreen, PID control with auto-tuning, and setpoints based on segmented curves. They include level and foam alarms with automatic replenishment and addition of defoamer, an event log, batch reports, and password management.
- Industrial. The 500- and 1,000-liter units feature five electrodes for automatic control, peristaltic feed pumps, an automatically lifting lid, and a Siemens S7-1200 series PLC. Industrial and solid-phase fermenters include remote monitoring and custom automation.
Before making your choice, answer three questions: Is your process batch or fed-batch? Do you need complete traceability of the data for each batch for an audit? And should the equipment integrate with the SCADA system or with your plant’s control system? An “yes” to the second or third question means you’ll need a higher level of automation than a simple desktop controller can provide.
5. What validation and documentation does your industry require?
An agricultural bio-input is not validated in the same way as a pharmaceutical process, and the cost of getting the regulatory level wrong becomes apparent at the end of the project, when the equipment has already been installed.
When it comes to design, here are the points you should review:
- 316L stainless steel and the absence of dead corners in the tank, which facilitate cleaning and reduce the risk of contamination.
- Special sampling and discharge valves, both in the tank and in the transfer lines.
- In-place cleaning and sterilization (CIP/SIP) in the scaling lines.
- Built to GMP standards. Techmi Bio Pharma, with a capacity of 20 to 50 L, is designed for laboratories and processes that require GMP compliance.
In documentation and qualification, define—starting with the URS, not at the end—what your auditor or client will ask of you: the equipment documentation package, factory and site acceptance tests (FAT and SAT), and installation, operational, and performance qualifications (IQ, OQ, and PQ). If your process is pharmaceutical, also verify how the control system manages data integrity: user access with passwords, event and alarm logging, and traceability for each batch.
Always ask the manufacturer, in writing, what documentation they provide and what regulations apply to each specific piece of equipment.
Which model in the lineup corresponds to each stage?
Overview of the Techmi Group’s range of bioreactors and fermenters by scale and application.
| Team | Scale | Primary use | Control and Automation |
|---|---|---|---|
| Techmi Bio Lab | 0.25 to 10 L (glass) | R&D, process development, enzymes, and bio-inputs | Agitation at 50 to 2,000 rpm, four peristaltic pumps, batch and fed-batch |
| Bio Lab with two tanks | 0.25 to 10 L | Parallel comparative tests, kLa studies, and scaling | Temperature ±0.1 °C, pH, DO, and agitation, recording, and traceability |
| Station with multiple cups | Several glasses of small volume | Strain screening and medium optimization | Independent control per cup, 0 to 1,000 rpm, programmable recipes |
| Techmi Bio Pilot | 20, 30, and 50 L (316L) | Scaling, parameter determination, seed amplification | Siemens PLC, 10″ display, PID with auto-tuning, batch reports |
| Techmi Bio Pharma | 20, 30, and 50 L (316L) | Processes that require GMP, pharmaceutical, and biotechnology standards | Curves by section, level and foam alarms, event log |
| Techmi Bio 500 | 500 L (200 to 400 L of working volume) | Small-scale production and intermediate handling of trains | Five electrodes, PLC Siemens S7-1200, cover with automatic lift |
| Techmi Bio 1000 | 1,000 L (800 to 900 L of working volume) | Small or medium-scale production, dual-tank version with two tanks | Five electrodes, PLC Siemens S7-1200, cover with automatic lift |
| Fermentation scale-up trains | 20 to 30,000 L | Complete production line for scaling with CIP/SIP | Temperature ±0.1 °C, pH 2 to 12 (±0.01), DO 0 to 100%, up to 3 bar |
| Industrial 30.000 L | Up to 30,000 L, custom-made | Large-scale industrial production | Automation and custom workflow, remote monitoring |
| Bio Fes FSS | 10 to 1,000 L and custom sizes (solids) | Solid-state fermentation of fungi | Temperature, humidity, and speed (0 to 22 rpm), SCADA and remote monitoring |
Checklist para tu URS
Before requesting a quote, make sure your specifications meet the following requirements:
- Workload (non-nominal) and the stage of the scaling chain in which the equipment will be used.
- Organism, type of fermentation (submerged or solid-state), and requirements for agitation, shear, and foam.
- Peak oxygen demand (OUR) and the OTR or kLa values guaranteed by the manufacturer.
- Operating mode (batch or fed-batch), level of automation, data logging, and SCADA integration.
- Materials, hygienic design, CIP/SIP, and applicable regulations (GMP or other).
- Required documentation and qualifications: FAT, SAT, IQ, OQ, and PQ.
- Required documentation and qualifications: FAT, SAT, IQ, OQ, and PQ.
Answering these questions before requesting a quote helps prevent oversizing the equipment, reduces the number of design iterations, and shortens the path to the first production run.
Because choosing the right bioreactor isn’t about choosing the largest one—it’s about choosing the one that best suits your process, today and at every scale.
Are you considering purchasing a bioreactor, or do you need to scale up an existing process? Our team can review your situation and help you determine the right solution for each stage. Email us at info@techmigroup.com or contact us.