Power station partners with start up to turn carbon dioxide into fish feed

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Deep Branch Biotechnology wants to tackle two global challenges with one solution.

British electrical power generation company Drax has partnered with UK start-up Deep Branch Biotechnology to turn emissions into fish food. Helped via funding from Innovate UK, Deep Branch is looking to aquaculture as a test bed for sustainable protein production whilst also encouraging CO2 capture.

Protein
“The process of creating the protein we eat on our plates is extremely resource inefficient,” said Deep Branch CEO Peter Rowe. “It takes about 6 kilograms (kg) of feed to produce one kg of pork. Soy is one of the world’s most widely produced crops but more than 90% of it goes into animal feed.”

The partnership will see Deep Branch connect directly to a source of CO2, with the start-up taking up residence in Drax’s carbon capture usage and storage (CCUS) incubator space. Here, flue gas from one of Drax’s biomass power generation units will be fed into Deep Branch’s system, along with hydrogen, enabling a process known as gas fermentation to take place.

Fermentation
“Normally when people think of fermentation, they think about something like wine, where sugar is converted into alcohol with a yeast acting as the biological catalyst,” said Rowe. “Our process, however, uses CO2 and hydrogen instead of sugar. Rather than yeast, our proprietary bacterium acts as the biological catalyst and converts these gases into protein.”

The resulting product is single cell protein, which comes out as a milk-like liquid when harvested. It’s then dried into powder and 70% of what remains are proteins that can be used as a fishmeal replacement.

Microbes
One of the advantages of Deep Branch’s system is that rather than requiring energy to separate CO2, flue gas can be delivered directly to microbes, which can convert up to 70% of the captured CO2 into proteins. But for such a system to have a real impact it needs to be deployed at scale.

The process has been trialled in labs with ten kg of CO2 producing seven kg of protein. What this new partnership with Drax offers is the opportunity to test Deep Branch’s process and technology at grid-scale. And while Deep Branch is focusing on aquaculture for now, the concept could potentially reach much further through the food chain.

“Because Drax’s biomass units are carbon neutral at the point of generation, the process creates an extremely low-carbon protein,” explained Rowe. “If you divorce the negative environmental impacts of industries like agriculture from its growth then you can provide more whilst impacting less.”