New technology regulates pH

Using the developed MRS systems, the technical design and software for the autonomous regulation of pH in bioreactors could be illustrated. The green microalga Scenedesmus rubescens has a pH growth optimum of around pH 7 to pH 7.5. Cultivation in more basic or more acidic environments delays its growth and changes its metabolism. A system using pH sensors, signal converters and solenoid valves for controlled CO2 gassing was set up. A single-board computer (Raspberry Pi) together with a web server was used for control and data recording. The system flawlessly controlled the pH at a pre-specified value throughout the test period. The system can also be easily expanded to large systems and for other parameters. By using a single-board computer, the system requires only minimal space and energy, and it can also be purchased inexpensively.