Automation of Upstream Bioprocessing
Another important aspect of microfermentations is automation. While the BioLector provides most of the fermentation parameters online, detecting target proteins or substrate concentrations online is not always possible. Therefore, it is useful to combine the BioLector with an automated liquid-handling platform.
The Robolector includes pipetting robots and the BioLector (Figure 3). RoboLector software provides signal-triggered manipulation of the fermentation process in the BioLector.
At a predefined set point, e.g., a certain biomass concentration or DOT level, the system is able to add inducers or substrates to each individual well or to take samples out of them. Sampled fermentation broths can immediately be cooled down to -10ºC in a cooling station placed on the liquid-handling platform. The system can also further process the samples or disrupted cells in a centrifuge to recover the supernatant for further downstream processing or analysis.
The RoboLector platform was recently evaluated in an induction-profiling experiment with E. coli in which inducer concentrations of IPTG and induction times were varied. The results showed that maximum space-time yields could be achieved at low inducer concentrations of 50 mM IPTG and induction times between 3.5 to 4.0 hours.
The BioLector facilitates high-throughput fermentations with online monitoring of all relevant fermentation parameters in shaken microtiter plates. The development of new flower-shaped well geometries, realized in the Flowerplate, provide unlimited oxygen transfer conditions (OTR up to 0.2 mol/L/h) for most microbial fermentation applications, thus, avoiding the need for active pH control due to the production of organic acids under micro-aerobic conditions.
RoboLector allows for the automation of upstream bioprocessing with standard liquid-handling systems. In addition, its use makes it possible for fermentations to be conducted automatically in a high-throughput screening environment.