Labfors5 benchtop bioreactor
Introducing our newest piece of equipment; the Labfors5 benchtop bioreactor from Infors!
By Ailsa Townley, Cell Scientist
Over the past year we have been receiving increasing numbers of requests for larger final quantities of protein. Therefore, we have had to scale up the initial cell culture grows to meet this demand. This has meant expressing in many individual shake flasks and our microbial incubators were filling up fast. As such, we’ve invested in a benchtop bioreactor which gives us a single vessel with a 10L working volume in which we can produce large homogenous batches of E. coli expressed protein.
Not only will this bioreactor increase our cell culturing capacity, but it gives our scientists greater monitoring capabilities and control over the grow including the pH and dissolved oxygen levels. This should lead to more consistent outputs with repeat batches as well as an increased total protein yield.
Initial growth optimisation experiments have been carried out with some of our in-house tool proteins, an example of which is shown below.
Figure 1: Fermenter time course data
• Turbidity (Green / turquoise)
• Stirrer (Pink)
• pH (Lime)
• Dissolved Oxygen (Orange)
• Temperature (Purple)
In a controlled experiment with a standardised working volume, we compared expression of a HRV3C construct between shake flasks and the bioreactor. Using our standard flask method, we obtained a cell pellet yield of 11.25g per litre of culture. After purification, this resulted in a protein yield of 22.5mg per litre of culture. In the comparative bioreactor batch (with controlled pH and enhanced oxygenation), we were able to achieve higher cell densities, resulting in a cell pellet yield of 13.85g per litre of culture. Furthermore, the protein expression per gram of cell pellet increased. This led to an overall protein yield of 42.4mg per litre of culture, nearly double the protein yield obtained from the flask method.
Following optimisation of standard grow conditions, we have also been able to grow client proteins. We are now looking to further develop our procedures to include feeding and temperature variations which can be adapted to suit individual protein target needs.
In summary
We have established protocols and methods to successfully run the new Labfors5 benchtop bioreactor. This gives us an expanded capability that we are now able to offer to support our client projects. The controller is able to cope with multiple bioreactors, giving us the option to expand in the future if required.
