Carbon captured from industry could be channelled into the food聽chain 鈥� a process that might help to reduce the emissions from聽agriculture.
UK-based company Deep Branch Biotechnology has recently finished testing a method for turning carbon dioxide into animal feed. It is now teaming up聽with two CO2 emitters 鈥� one that generates electricity and one聽that produces cement 鈥� for trials over 18 months, in which it聽will convert the gas into up to 100聽kilograms of protein to be fed聽to fish and livestock.
The firm鈥檚 method relies on an聽edible strain of bacteria that consumes CO2. The bacteria grow and reproduce when fed the gas, and can be regularly harvested, while still maintaining a colony.
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Once dried out, around 70 per cent of the remaining material is聽protein. These microbes can generate everything they need from CO2 and the basic building blocks of life, says Peter Rowe at Deep Branch.
Around a third of all cropland is聽used to grow animal feed, according to the . And around 17 per cent of all fish caught globally are turned into feed for commercial fisheries, found an analysis by the .
The hope is that Deep Branch鈥檚 technology can be used to reduce these numbers and provide an extra incentive for CO2 to be captured from industry before it聽enters the atmosphere. The Intergovernmental Panel on Climate Change has said that carbon capture will be necessary to limit global warming to 1.5掳C.
鈥淓very little bit helps,鈥� says Ronald Hardy at the University of聽Idaho. However, he is sceptical this will be on a large enough scale to affect global emissions.
Deep Branch plans to build a larger production facility by 2021 so it can produce several tonnes of聽protein per year.
The idea of using bacteria to make protein for animal feed has聽been around since the 1970s, but it only recently became economically viable.
What has changed is that fishmeal聽鈥� a powder obtained from milling and drying fish parts聽鈥� has become more expensive. This has traditionally been used as a food source for fisheries, but production has failed聽to keep pace with growing human demand for fish.
Other firms are also exploring similar approaches to Deep Branch, such as Calysta in the US聽and Unibio in Denmark.
Both these companies use bacteria to produce protein to feed聽fish and livestock. However, rather than CO2鈥�, the microbes they聽use consume another greenhouse gas, methane.
Beyond animal feed, companies such as Climeworks in Switzerland use CO2 from the atmosphere to carbonate beer and soft drinks, and as dry ice for freezing food. They also fill greenhouses with the gas to boost plant photosynthesis and therefore growth.
