Building a biofuel-boosting Swiss Army knife

Researchers at Michigan State University have built a molecular Swiss Army knife that streamlines the molecular machinery of cyanobacteria, also known as blue-green algae, making biofuels and other green chemical production from these organisms more viable.

The team has done in a year what has taken millions of years to evolve. In the current issue of Plant Cell, they describe how they fabricated a synthetic protein that not only improves the assembly of the carbon-fixing factory of cyanobacteria, but also provides a proof of concept for a device that could potentially improve plant photosynthesis or be used to install new metabolic pathways in bacteria.

"The multifunctional protein we've built can be compared to a Swiss Army knife," said Raul Gonzalez-Esquer, MSU doctoral researcher and the paper's lead author. "From known, existing parts, we've built a new protein that does several essential functions."

Gonzalez-Esquer and his colleagues modernized the factory by updating the carboxysome, a particularly complex BMC that requires a series of protein-protein interactions involving at least six gene products to form a metabolic core that takes CO2 out of the atmosphere and converts it into sugar. To streamline this process, the team created a hybrid protein in cyanobacteria, organisms that have many potential uses for making green chemicals or biofuels.

The new protein replaces four gene products, yet still supports photosynthesis. Reducing the number of genes needed to build carboxysomes should facilitate the transfer of carboxysomes into plants. This installation should help plants' ability to fix carbon dioxide. Improving their capacity to remove CO2 from the atmosphere makes it a win-win, Gonzalez-Esquer said.