Algae are small climate savers. Already extremely efficient in their natural photosynthesis outdoors, they bind ten times more carbon dioxide (CO₂) than land plants. In bioreactors with appropriate sensors, control technology and automation, the efficiency of algae can be increased to hundreds of times that of land plants. Therefore, they hold considerable potential for a climate-neutral circular economy. With the PhotoBionicCell research project, we are demonstrating a possible approach for the industrial biologization of tomorrow.
The bioreactor can be used to automatically cultivate algae and control their growth. For this purpose, the algae liquid is pumped upwards into the surface collectors, where it is distributed in a uniform flow and then flows back into the cultivator. During this circulation, the algae cells convert sunlight, carbon dioxide and water into oxygen and chemical energy carriers or organic valuable substances by means of photosynthesis in their chloroplasts. In this way, the biomass is cultivated in a closed cycle that is highly efficient and saves resources.
In order to create the best possible conditions for the microorganisms, the interaction of proven control technology with the latest automation components comes into play. A holistic gassing concept ensures that the carbon dioxide extracted from the air is evenly distributed in the circulating biofluid.
A major challenge with bioreactors is to accurately determine the amount of biomass. For this purpose, our developers rely on a quantum technology sensor from the start-up Q.ANT. This provides precise and real-time information about the growth of the organisms. The algae are fed to it automatically and continuously by Festo microfluidics. The quantum sensor isable to optically detect individual cells so that the amount of biomasscan be determined exactly. In addition, it examines the cells for their vitality. Only then is it possible to react to process events in advance and to regulate them.
Depending on the nutrients supplied to the algal biomass, fatty acids, color pigments and surfactants are formed as products of their metabolic processes. They serve as starting materials for the production of medicines, foodstuffs, plastics, cosmetics or fuels. Unlike petroleum-based products, biologically based end products can usually be biodegraded and - in keeping with an overall circular economy - recycled in a climate-neutral process.
For the work on PhotoBionicCell, our researchers focused on the cultivation of the blue-green algae Synechocystis. It produces color pigments, omega-3 fatty acids and polyhydroxybutyric acid (PHB). The resulting PHB can be processed into a filament for 3D printing by adding other substances. With this modern production technology, complex shapes of sustainable plastic components or packaging can be produced in a short time. In the PhotoBionicCell, for example, specific fastening clips made of the bioplastic are installed.
Many laboratory analyses have been done manually up to now. This is time-consuming and can lead to errors. By automating such laboratory systems, all necessary data could be read directly and in real time in the future, and researchers could better concentrate on their core tasks.
PhotoBionicCell is completed by a specially developed software. Your dashboard allows you to map multiple photobioreactors with current data and live images. This allows manual parameter changes and the corresponding evaluations to be made around the clock, even remotely. This allows users to react to changes in the bioreactor at any time and, for example, initiate product harvesting at the optimal time.
The digitized laboratory is supplemented by an augmented reality application. A tablet can be used to augment reality to visualize technical processes, process parameters and information about processes inside the bioreactor.
Our developers also use artificial intelligence (AI) methods to analyze the data. Thus, the bioreactor can be optimized either to propagate the algal cultures or to maintain predetermined growth parameters with minimal energy input. It could also be used to predict the durability of valves and other components. The use of digital twins created with the help of AI would also be conceivable. In the future, they could be used to simulate and virtually map complete life cycles of bioreactors. The expected cell growth of a wide variety of microorganisms could then also be estimated with great accuracy even before the physical construction of a real system.
In addition to optimization of laboratory facilities with automation and digitalization, so-called artificial photosynthesis offers another promising perspective for even more efficient cultivation of biomass. With our project partner Max Planck Institute for Terrestrial Microbiology Marburg, we have developed an automated dispenser to improve individual enzymes of photosynthesis. To do this, thousands of variants of an enzyme have to be tested. Compared to manual pipetting, the new automatic dispenser works much faster and eliminates errors. In addition, the automatic machine can be adapted to new tasks in seconds.
But it is not only individual building blocks of photosynthesis that can be optimized. The scientists are working on digitally optimizing entire metabolic pathways. This approach is called synthetic biology. A computer-optimized metabolic pathway is packaged into synthetically produced cells called droplets. These have a diameter of around 90 micrometers and contain all the necessary enzymes and biocatalysts. This enables them - like their biological models - to fix carbon dioxide using light energy.
Even though we are still in the middle of the development process, the potential for the future is already apparent today. If expertise in automation and basic research come together, the path to carbon-neutral production on an industrial scale will be implemented much faster. Therefore, we are doing research in the field of biologization.