Frequently Asked Question

Regarding laboratory bioreactors
1) What are the applications of laboratory bioreactors?
Our laboratory bioreactors have options for both microbial fermentations and cell culture cultivation processes. These bioreactors can be used for education, production, and research & development.  Possible applications include the manufacture of yeasts, enzymes, bio-fertilizers, vaccines, probiotics, bioplastics, mammalian cells, cultured meat, etc.
2) Which volumes of laboratory bioreactors are available?
We offer three bioreactors with the following total volumes: 1-, 6- and 15- liters. Each of these is autoclavable.

3) How is temperature regulated in bioreactors?
Firstly, a jacket is inserted into the metallic bottom of the 6- and 15-liter bioreactors, through which water will flow, which is thermoregulated by the built-in thermostat. This is a safe and reliable method, and an easy solution for temperature control. 
In the twin 1-liter bioreactor on the other hand, the temperature control system is equipped with a Peltier element. This makes temperature control possible without the need to connect to a cooling water source. This also applies to the cooling of the condenser.      

4) How many peristaltic pumps are included in the basic configurations of bioreactors?
All laboratory bioreactors have configurable peristaltic pumps with variable speed. This mean that each pump can be configured to one of following titration functions: base, acid, or foam-level. The 6- and 15-liter bioreactors have four, but the 1-liter bioreactor has three variable speed peristaltic pumps.
Additionally, external peristaltic pump can be connected, controlled by a 4-20 mA signal. 
5) What parameters can be measured and controlled?
In the basic version the following variables can be controlled:
  • Temperature
  • pH
  • Dissolved oxygen
  • Antifoam levels.
Optional controllable variables include:
  • Overpressure
  • Methanol/ethanol concentration.
Optional measurable variables include:
  • Concentration of Oxygen, Carbon dioxide and other gasses in outlet gas flow
  • Redox
  • Conductivity
  • Dissolved carbon dioxide
  • Cell density (total cells, viable cells)
  • Ethanol/methanol concentration
  • Volumetric oxygen mass transfer coefficient kLa.
6) Can overpressure be controlled in bioreactors?
Yes, this can be added as an option in our 6- and 15-liter bioreactors. An autoclavable pressure sensor can be installed, as well as an electrically controlled valve that is connected after the outlet filter. Overpressure can be controlled up to 1.6 bar.

7) How is the volumetric oxygen mass transfer coefficient kLa measured and what information does this parameter contain?
The volumetric oxygen mass transfer coefficient – kLa, is the parameter that controls the rate of oxygen transitions from the gas phase into the liquid phase. kLa shows numerically how efficiently oxygen, which is introduced through a sparger in the vessel, is dissipated and distributed in the medium by the mixer. In principle, kLa can be used to calculate the oxygen uptake rate, which correlates with biomass growth. This means that by monitoring kLa the growth of microorganisms can be evaluated in real time.
To calculate kLa automatically the bioreactor must be equipped with Oxygen and Carbon dioxide gas analyzers.
8) What type of mixers are available?
There are two options – The standard Rushton turbines or pitched blade impellers. Additionally, mixers can also be customized for specific applications.
Standard Rushton turbine mixers are recommended for bacterial and yeast microorganisms, while pitched blade impellers are more suitable for shear-sensitive microorganisms and viscous fermentation media.      
All solutions are provided with magnetically coupled mixers.
9) What coupling drive is used for the mixers and what maximal mixing intensity can be achieved in laboratory bioreactors?
In all laboratory bioreactors mixers with magnetic coupling are used. The mixing intensity is ensured by applying high mixer rotation speeds and mixers with parameters corresponding to real Rushton standard turbines (sometimes manufacturers apply mixers with reduced blade heights to ensure high enough mixer rotation speed). The maximal mixing rotation speed in the 1-liter laboratory bioreactor is 2000 rpm, in the 6-liter – 1300 rpm, and in the 15-liter – 750 rpm.
10) Is oxygen enrichment available?
 Yes, oxygen enrichment is available in all models. In the basic version it uses two solenoid valves. Optional Thermal Mass Flow Controllers (TMFC) can be used to control the air and oxygen supply.
11) How is dissolved oxygen (DO) cascade control realized?
In all our laboratory bioreactors three DO cascades are available: mixer rotation speed, oxygen enrichment and substrate feeding. The number of cascades is selected before the process. In the feeding cascade, the initial feeding rate of the substrate is set according to the adjusted profile (if a fermentation has been run according to the adjusted profile before) or with a defined maximum substrate feeding limit (if there has not been a feed before).
12) How can fed-batch be implemented?
There are two options available.
  • In the basic version it is done by adjusting time dependent feeding rate profiles. Between two defined feeding points a step wise, linear, or exponential profile can be selected.
  • We also offer model-based feeding control. Using this method feeding rates are controlled automatically by a program which optimizes the dosage based on mathematical models
13) What types of sterilizable pH and DO sensors can be used?
Polarographic, optical and Hamilton ARC sensors can be used. ARC sensors send 4-20 mA signals directly to the PLC allowing simultaneous information management via Bluetooth in smartphones or PC installed programs. This program generates a report about all calibration procedures, sterilization numbers, predicted service life. The lifetime of these sensors is longer compared to other types.
14) What is the difference between microbiological and cell culture bioreactors?
  • Different mixing conditions. For cell culture bioreactors, a sensitive shear mixer (in our case pitched blade impeller) is used with lower maximal revolutions speed.
  • Instead of a ring sparger, a micro sparger is used, and gas supply is also overhead instead of underneath.
  • Usually, the bottom sparger mixes four gasses (Air, oxygen, nitrogen, and carbon dioxide). Conversely, in the overhead only two gasses are mixed (Air and carbon dioxide)
15) What software do laboratory bioreactors use?
The process control of bioreactors is based on Siemens Simatic S7-1500 controllers. It is characterized by its high reliability and includes international service in any country with a Siemens office.
16) What SCADA is used for process control and fermentation data processing?
The SCADA is our own user-friendly development. It is based on the ARC Informatique PC Vue industrial development package, which gives wide possibilities for process data management and reporting according to the requirements of 21 CFR Part 11 (document from US Food and Drugs administration).
17) Can the bioreactor be controlled remotely from outside the laboratory?
Yes, with the remote-control function integrated in the SCADA software the fermentation process can be managed using a laptop, tablet, or smartphone from outside the laboratory.
18) Can remote service of bioreactor be provided through internet?
Yes. Our bioreactors are connected to internet with the help of Tosibox. The Tosibox allows remote access to our customer’s bioreactors control systems through the Internet. It is used for remote maintenance and program updates. If the customer is in need of support, they can contact us and we simply connect remotely to the bioreactor control system so we can diagnose the problem and give advice on how to solve it.