In a double-win for the environment, a team of researchers have managed to turn greenhouse gas emissions into an ingredient that could be used to feed livestock—potentially bypassing the need for vast tracts of farmland to grow crops. If developed at scale, their invention could help to sequester harmful emissions, while perhaps significantly reducing the pressure of global food systems on the land.
The study explores the concept of “synthetic nutrition” the researchers explain, “where all essential nutrients can be produced artificially, efficiently, and with a small footprint.”
The starting point for this impressive-sounding feat is an abundant resource: carbon dioxide. Thanks to growing innovations, researchers are finding ways to use CO2 as an industrial waste product, and break it down into parts that are then used as building blocks to make other useful ingredients.
In fact, the researchers on the new Chem Catalysis study were inspired by the work of another team who recently found a way to produce starch from CO2, using methanol as an intermediate ingredient. They were curious about whether they could push this combination, using a fleet of enzymes, to make another important macronutrient: a protein substitute for use in animal feed.
Usually, such proteins are derived from crops like soybeans, produced at industrial scales that can have huge impacts on the landscape and biodiversity, driving pollution and expelling emissions. Artificially manufacturing such essential proteins instead, has the potential to decouple feed from the land.
The researchers describe how they used CO2 (which in the future when they upscale will be extracted from the air and from industrial waste streams), then combined it with renewable hydrogen to make methanol, in a process powered by wind and solar energy. Once they had this raw material, they applied a series of synthetic enzymes in an eight-step process, in finely-tuned combinations that eventually produced an amino acid called L-alanine. This ingredient is crucial for making proteins, and could be the animal feed substitute that they were looking for. It may even be useful in one day producing cultured meat, the researchers believe.
Importantly, they managed to use up the majority of the raw materials in their manufacturing process to make the amino acids, meaning that if scaled up, they should be able to produce high ingredient yields efficiently.
There are other ways to synthesise L-alanine, but these involve emissions-intensive processes requiring petroleum products, or the fermentation of glucose, which carries its own footprint. This new method bypasses the problem by repurposing a “climate-damaging waste stream” and powering the process with green energy, the team explains.
Most extraordinarily, it totally decouples production from the land: “Compared to plant cultivation, much less land is needed to produce the same amount of L-alanine if the energy for this is obtained from solar plants or wind power,” the researchers say.
It’s still very early days for this discovery, and the process needs to be moved from a lab environment and scaled up. But in all likelihood, the applications for synthetic nutrition will grow.
“Estimations show that the demand for animal protein will increase by almost 50% in 2050,” the researchers write. “However, animal foods produce more greenhouse gases, so alternative sources have to take their place.”
Sieber et. al. “Cell-free enzymatic L-alanine synthesis from green methanol.” Chem Catalysis. 2023.
Post updated 15 May at 06:30 MST.