bioREACTOR 8

Temperature control
The temperature of the bioreactor block is recorded via an internal Pt100 sensor and can be controlled externally via a thermostat. To avoid evaporation loss, the headspace of the reaction vessels can be cooled down with an reflux cooler. The evaporated water condenses and rests in the reaction vessel. The bioREACTOR with pH and DO sensors can be used at temperatures from 10°C up to 50°C. Temperatures from 0°C up to 65°C are possible without sensors.

Working volume
The working volume of the culture vessels is between 8 and 15 milliliters. This allows repeated sampling without strong reduction of the fermentation volume but also enough capacity for adding pH correction agents or substrates.

Real-time measurement of pH and DO
pH and dissolved oxygen can be measured in real time during the entire duration of the experiment using a non-invasive optical sensor system. For this, the bottom of the culture vessels are equipped with small sensor spots (pH and O₂ sensitive luminescent dyes). The fluorometric measurement is provided by stimulation with light and measurement of the decay time (DLR=Dual Lifetime Referencing Principle, PreSens GmbH). The measuring range lies between 4.0 and 7.5 for the pH and between 0 and 50 % for the dissolved oxygen.

Reaction vessels (disposables)
The disposable culture vessels equipped with sensor points are made of polystyrene and sterile-packed in a set of 2. This allows a time saving and easy equipping of the bioREACTOR. The special geometry of the culture vessels with baffles in combination with the used stirring elements lead to a very good mixing of the medium and to high oxygen transfer rates.

Gas supply
The continuous gas supply of the bioREACTOR can be realized via a gas mixing station. Depending on the used gases (O₂, N₂, air) aerobic and anaerobic cultivations are possible. The gas transfer into the medium of the culture vessels is done passively through the gas inducing, inductive driven magnetic stirring elements. The gas tranfer rate can be adjusted via the stirring speed.

Stirring bar monitoring
In rare cases, very high cell densities or a high proportion of solids in the medium can cause individual stirring elements to fail. This will be detected in a few seconds and the stirrers will be restarted automatically. Therewith, the stirrer monitoring guarantees a secure experimental run.

Intelligent software
The stand-alone software enables parallel operation of several bioREACTOR 8 and/or bioREACTOR 48 units. At the same time, already finished runs can be compared with new running experiments.

Autoclavability and sterility
All parts that come into contact with the medium are autoclavable or sterile-packed disposable materials. The gassing unit with the fixed stirring elements is completely autoclavable In addition, the complete bioreactor block is sterilisable with ethanol. The disposable culture vessels are sterile packed and were disposed after the experiment. During the experiment, the sterile headspace gassing avoids cross and external contaminations.

Scalability
The precisely defined geometry of the stirring bodies, the precisely characterized process engineering parameters and the power and oxygen input (_kLa > 0.4 ^s-1) through the magnetic stirring bodies, which is comparable to that of conventional stirred tank reactors, enable simple scaling of the results to the liter scale.

Automation
The bioREACTOR can be operated as a desktop device (stand-alone) or fully automated by integration into a pipetting robot. The integration allows pH control, adding of substrates and taking samples out of the reaction vessels. Therewith feeding strategies can be analysed, an online measurement of the optical density (OD) can be made or samples for additional tests can be taken out of the vessels.