Helena Schulz-Mirbach and Frederik Schmidt Receive the 2026 VAAM Doctoral Award
Two former doctoral researchers from the Max Planck Institute for Terrestrial Microbiology in Marburg have been awarded the 2026 VAAM Doctoral Prize, endowed with €2,000, by the German Society for General and Applied Microbiology (VAAM). The awarded research focuses on utilizing climate-damaging CO₂ as a valuable resource, enabling direct biological availability of nitrogen, and efficiently establishing novel metabolic pathways.
Microorganisms lie at the heart of global biogeochemical cycles, as their metabolic pathways make nitrogen (N₂) and CO₂ biologically accessible for life. Strategically manipulating these microbial capabilities at the genetic level could pave the way for environmentally friendly production methods of essential elements.
Central to microbial metabolism are enzymes—biological catalysts that rapidly convert specific substrates into products. In recognition of their pioneering work in this field, the German Society for General and Applied Microbiology (VAAM) has honored Helena Schulz-Mirbach and Frederik Schmidt with the 2026 Doctoral Prize.
To harness an enzyme in innovative bioproduction processes, a deep understanding of its functional principles and molecular reaction mechanisms is essential. This is precisely where Frederik Schmidt’s doctoral research began. "Nitrogenases are the only enzymes capable of fixing atmospheric molecular nitrogen (N₂) and converting it into bioavailable ammonium," he explains. His dissertation, conducted in Dr. Johannes Rebelein’s team, focused on the function of so-called iron nitrogenase—an enzyme notable not only for its ability to fix nitrogen but also for its strong activity in converting CO₂.
To investigate this surprising capability, Frederik Schmidt isolated the enzyme from the bacterium Rhodobacter capsulatus and analyzed the competitive conversion of nitrogen and CO₂ in test tubes. Together with Niels Oehlmann, Marcello Herzog, and Annelise Goldmann, he achieved the first-ever demonstration that iron nitrogenase efficiently converts CO₂ under normal atmospheric pressure and temperature conditions. The resulting products serve as valuable building blocks for producing various basic chemicals and biofuels. “Frederik Schmidt’s outstanding biochemical and structural studies provide crucial foundations for the optimization of CO₂ conversion by nitrogenases and open up new perspectives for sustainable biotechnologiscal processes,” says his supervisor, Johannes Rebelein.
The fixation of the greenhouse gas CO₂ was also central to Helena Schulz-Mirbach’s research. Since the core enzyme of natural CO₂ fixation, Rubisco, operates slowly and non-specifically, CO₂ is not captured as efficiently as theoretically possible. Therefore, synthetic biologists are actively searching for and developing new enzymes and artificial reaction sequences to improve CO₂ conversion. While such systems have already been successfully implemented in test tubes, their future sustainable biotechnological application—such as in bioreactors—requires living bacteria, like the model organism Escherichia coli.
In her doctoral thesis, Helena Schulz-Mirbach developed strategies and tools for establishing artificial CO₂ fixation pathways in complex cellular environments. To this end, she engineered bacterial strains whose growth was coupled with the desired reaction cascades. Of the hundreds of enzymes and metabolic pathways she tested, she isolated improved variants. "To accomplish this, I developed MEVIS, an intelligent system that uses machine learning and robotics to significantly reduce the time-consuming process of developing, selecting, and implementing traits," explains the researcher. Together with Philipp Wichmann and Ari Satanowski, she developed a new enzyme that could be relevant for CO₂ fixation and bioplastic production in the future. "Helena Schulz-Mirbach is a pioneer in synthetic biology, revolutionizing the development of new biotechnological processes through an elegant combination of high-throughput experiments and machine learning," says Tobias Erb, in whose lab Schulz-Mirbach conducted her doctoral research.Helena Schulz-Mirbach is currently continuing her research at Stanford University in the group of Prof. Mike Jewett, aiming to combine the insights from her doctoral work with extracellular approaches. Frederik Schmidt will begin his research at the University of Bern in May 2026, joining Prof. Rebecca Buller’s group to advance new knowledge in the practical application of enzymes in biocatalytic processes.