German scientists show how microbe transforms industrial waste gases into ethanol

In Germany, scientists wondered how do you turn toxic waste into fuel? Ask the microbe. A team of scientists from the Max Planck Institute for Marine Microbiology, together with a colleague from the Max Planck Institute of Molecular Cell Biology and Genetics, experimentally demonstrates the molecular tricks used by the gas-converting microbe Clostridium autoethanogenum to transform industrial waste gases into ethanol—a finding with enormous implications for sustainable fuel and chemical production.

First isolated from rabbit droppings, Clostridium autoethanogenum can thrive on pure carbon monoxide, a deadly gas for most organisms, including human beings. This extraordinary microbe consumes the poison to build cellular materials from the carbon and derives its energy through successive chemical reactions. These reactions can help to produce valuable chemicals and fuels, perfect for driving sustainable biotechnology.

While the organism is currently widely used in industrial plants to produce ethanol, the exact mechanism behind its ethanol production remains unclear. A key step suspected in the reaction was the reduction of acetate to acetaldehyde. However, some scientists did not believe this was possible to carry out for organisms. This study, published in Nature Chemical Biology, now settles this dispute and solves the mystery.