Energy Boost for Synthetic Cells

An artificial cell uses oxygen to generate energy for carbon fixation

An international team at the Max Planck Institute for Terrestrial Microbiology have built from the bottom-up a “synthetic-biological battery” that reduces the dependence of chemical reaction networks on external energy sources. Coupled to a synthetic carbon-fixing cycle (CETCH), the combined system derives both energy and carbon from two primary components of our atmosphere—oxygen and carbon dioxide (CO₂). This study marks a step forward toward a fully self-energising artificial cell for sustainable carbon transformations.

In a nutshell:

• Researchers at the Max Planck Institute for Terrestrial Microbiology have developed a synthetic biological energy supply: a tailor-made artificial respiratory chain mimicking the mitochondria.
• The synthetic biological battery makes it possible to recover energy that would otherwise be lost in wasteful oxidative reactions, thereby reducing dependence on external energy sources.
• When integrated with the synthetic CETCH cycle for carbon capture, the synthetic biological battery accelerates oxidative reaction steps and CO₂ uptake
• Illustrating the impact of fundamental research, the insights inspired new technologies, such as the development of a stable membrane-based biosensor platform by the spinoff DynaPore.

In synthetic biology, researchers develop cell-free systems: miniature factories that perform specific tasks without requiring a living cellular environment. These systems aim to be autonomous and self-sustaining, emulating the efficiency of natural biological processes.

A key innovation in this field is the CETCH cycle—a synthetic reaction network, essentially a chemical engine—that converts carbon dioxide into organic matter. This process mirrors photosynthesis in plants, where the greenhouse gas CO₂ is fixed and transformed into valuable compounds. Scientists have already integrated feed-forward loops, biochemical circuits that enable the system to produce its own enzymes. However, a major challenge to achieving true autonomy remains the supply of energy. For a system to be genuinely self-sustaining, it must generate its own energy rather than rely on external sources.

Minimal respiratory chain speeds up cell-free metabolic processes

An international team led by Professor Tobias Erb engineered an integrated synthetic-biological “battery” modelled after the natural respiratory chain—the cellular machinery responsible for energy production. Cells use oxygen to generate energy, creating an electrical potential across the cell membrane that powers biosynthesis. However, even in simple organisms such as bacteria, this process involves more than 50 components.

“Cellular respiration is incredibly complex and closely integrated with the cell’s natural metabolism, making it difficult to repurpose for new applications,” says Dr. Owen Jarman, first author of the study. “That’s why I set out to use synthetic biology to redesign cellular respiration specifically for our artificial CO₂-fixation system.” The researchers equipped empty artificial cell compartments with a minimal, carefully selected set of respiratory components. “Once we coupled this customised respiratory system to our artificial CO₂ metabolic pathways, we observed faster CO₂ conversion,” reports Owen Jarman. “We also demonstrated that more energy could be directed toward the CO₂ conversion process.”

Thus by implementing the tailored energy modules, the external energy dependencies of metabolic processes were effectively reduced. The team could also demonstrate that the energy module can power other essential biological functions, such as the machinery that reads DNA to synthesise proteins. Futhermore, by using multiple entry points, the system allows the use of multipurpose feedstocks, such as formate, further streamlining cell-free designs.

Basic research inspired new sensor technologies

Although the engineered cell compartments were developed for CO₂ fixation, their potential applications extend beyond this purpose. Currently, Owen Jarman explores how insights from this fundamental research can be translated into practical technologies. He co-founded the spin-off project DynaPore, which develop electronic chips that hold stable membranes, enabling the creation of novel biosensors and diagnostic tools based on monitoring impedance changes across synthetic membranes. “This example demonstrates how fundamental research can lead to new technologies with applications in unexpected fields,” states Tobias Erb, project supervisor. “It also highlights the transformative potential of synthetic biology.”

Together with Professor Petra Schwille, Director at the Max Planck Institute of Biochemistry, Tobias Erb leads the SynCell nExUs network, which aims to strengthen research collaborations across Europe. “From carbon capture to innovative technology development, synthetic cell research offers promising pathways to address some of today’s most pressing challenges,” states Tobias Erb.