All of the food you’ve ever eaten was made with sunlight captured by plants just a few months or years before you ate it. But some of the energy on your plate could soon come from sunlight captured by plants millions of years ago, thanks to plans to feed livestock with fossil fuels.
A biotechnology company called Calysta, based in Menlo Park, California, is set to announce the first ever large-scale factory that uses microbes to turn natural gas – methane – into a high-protein food for the animals we eat. The factory, which will be built in the US in collaboration with food-giant Cargill, will produce 200,000 tonnes of feed a year.
The methane-made food has already been approved in the European Union for feeding to farmed fish and livestock such as pigs. Calysta is seeking approval in the US, too – and not just for farm animals. “We want to take it all the way to cats and dogs, and potentially even humans,” says the head of Calysta, Alan Shaw.
In September, Calysta opened a small facility in Teesside in the UK to produce up to 100 tonnes a year of feed for farmed fish. Unibio, a rival biotech company based in London, opened a similar-sized facility in Denmark in October. Both companies want to rapidly scale up production.
Is turning fossil fuels into food for livestock a good idea? That depends on what you think is most important when it comes to protecting the environment.
If done on a large scale, the process would reduce the demand for land to grow food for livestock, as well as the demand for fish meal to feed to farmed fish. “You need millions of tonnes to have an impact,” says Shaw.
But it would also increase emissions of carbon dioxide, accelerating global warming. “Using fossil fuels as an energy source as opposed to sunlight is not very environmentally sound,” says Bob Rees, who studies greenhouse-gas emissions from agriculture at Scotland’s Rural College in Edinburgh, UK.
The technology might one day also feed explorers of other planets. For instance, SpaceX head Elon Musk’s plans for Mars exploration include generating methane and oxygen for making rocket fuel. Some could be used to make food, too. “We have been in touch with SpaceX,” says Shaw.
The process relies on microbes that feed on methane. These methane-munching methanotrophs essentially “burn” methane (CH 4) to get energy, producing CO 2 and water as waste products. Some of this energy is then used to combine other methane molecules to make more-complex carbon molecules – food, in other words.
This ability first evolved billions of years ago – it likely predates photosynthesis – and today methanotrophs can be found wherever there’s methane to feast on, from cold seeps on the sea floor to ponds and marshes.
Some biologists think that “dark food” from these methanotrophs plays a much bigger role in many ecosystems than thought.
Calysta is using a bacterium called Methylococcus capsulatus. The bacteria are grown in vats, fed methane, and are then dried and turned into pellets.
The idea was first explored in the 1980s by Norway’s state-owned oil company, Statoil, which in the 2000s built a plant capable of producing 10,000 tonnes of feed a year. But at the time, gas prices were high and the product had not been approved in the EU. The plant was closed, and the technology was sold to Calysta.
With approval now in place and natural gas prices lower, Shaw is betting that the technology is ready for the big time – and rival company Unibio thinks so, too.
Both companies are promoting the process as having environmental benefits. Shaw has said it “heralds a new era in the race to sustainably feed the world’s growing population”. Unibio’s website goes further, claiming a “52% cut in CO2 emissions”. So are they right?
Calysta commissioned a report on the environmental impact of methane-derived food from the Carbon Trust, which advises governments and companies on how to reduce emissions. The report compared how much land is needed, how much water is used and how much CO 2 is emitted by the various ways of producing feed.
It concluded that when methane from a fossil source is used, several times as much CO 2 is produced per tonne of feed than by almost all other ways of making feed. Only chicken blood meal has higher average CO 2 emissions per tonne of feed.
Unibio’s claim is based on the fact that after the feed has been made – but not eaten – only half as much CO₂ will have been emitted into the atmosphere than if the gas were just burned, or flared.
But this is only half the story: in the long term, just as much CO 2 will be released. “Any carbon that is fixed into a food substance is going to be released as CO 2 back into the atmosphere eventually,” says Rees. “That claim really does not make any sense at all.”
“It is true that animals respire CO₂ in their metabolism, just as humans do. Our calculation does not take this into consideration,” says the head of Unibio, Henrik Busch-Larsen. “We believe the CO₂ calculation compared to gas flaring is valid but acknowledge it has to been seen in the context mentioned above.”
In theory, carbon emissions could be greatly reduced by using methane from a renewable source, such as biogas from farm waste or landfill sites. This would reduce emissions to levels comparable to those for feeds made from wheat or soya, for instance.
“Feeds that have lower carbon emissions, lower land use and lower water use are absolutely needed,” says Tom Cumberlege of the Carbon Trust, one of the authors of the report.
The catch is that there are no big and cheap sources of biogas. “It’s just not going to happen,” says Shaw. The US factory will use natural gas from a conventional source, not from fracking.
On the plus side, the report concluded that Calysta’s feed has tiny water and land use requirements compared with all the other methods of producing feeds. Some may think this is even more important than cutting carbon emissions.
The technology cannot be expected to do everything, Shaw says. “I’m addressing a food security issue and saving the oceans and not cutting down rainforests for soya,” he says. “Taking fish out of the sea that you then feed to other fish, that is unsustainable.”
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