Feeding Cows Space Food Could Reduce Greenhouse Gases

Agriculture is one of the biggest contributors to greenhouse gas emissions and it's not just burping and farting cows that are to blame. Growing crops to feed livestock is also a major problem for raising our global temperature—it takes up large areas of land and alters how carbon gets recycled in the atmosphere.

One alternative might be to feed cows, pigs, and chickens the food that NASA scientists developed in the 1960s to sustain their astronauts: bacteria. Specifically, bacteria could replace most of the protein component of animal feed, the part that right now mainly comes from soybeans.

Using an environmental impact model called MAgPIE, scientists estimated that replacing just 2 percent of animal feed, or 13 percent of the total protein in it, with “microbial protein” could reduce greenhouse gas emissions by 7 percent and land use by 6 percent.

That might not sound like a lot but the land saved is the equivalent to all of China’s cropland, Benjamin Bodirsky, an economist working on climate models, told me over the phone. “If you think about it on a global scale it’s really large… for a single technology,” he said.

The key advantage is producers could grow a lot of bacteria—quickly—in a small space. Some methods, such as feeding the bacteria natural gas or hydrogen, wouldn’t require any cropland at all. Producers could grow several kilograms of bacteria in a single hour while only taking up one cubic meter of space. Compare that to 16 soybean plants in a square meter space that can take up to 100 days to grow big enough to harvest.

That’s exactly why NASA toyed with the idea in the 1960s—to easily grow enough bacteria onboard space missions to sustain its astronauts. The idea was pretty quickly quashed when several test subjects began throwing up violently after reacting badly to a byproduct of the process.

Although it didn’t work for humans, the Soviets realized it might for animals, and set up factories in the 1970s to make microbial protein. By using petroleum as the bacterial food source, the Soviets avoided making the byproduct that made humans sick and, because the microbial protein only made up a portion of the feed, animals found it easier to digest.

The way it works is a mix of bacteria species is grown in a giant industrial fermenter by feeding them natural gas, biogas, hydrogen, or sugarcane. Once there’s enough bacteria, they get dried out into a powder that can be added to the other animal feed components such as hay, grains, or minerals.

The method is pretty much the same now as it was in the 1970s, except then petroleum was the main food source for bacteria and the Soviets were just starting to experiment with using natural gas.

When I asked environmental engineer Ilje Pikaar why microbial production for livestock didn’t continue, he told me it wasn’t economically viable at the time. Soybeans were cheap to grow and oil became expensive.

But now the whole process is cheaper, thanks to advances in biotechnology including automation or knowing exactly how much bacteria is needed for each feed input. And with highly unstable soybean prices the idea of space food for cows is back on the table.

The biggest push for the resurgence of microbial proteins, according to Pikaar, is our realization of agricultural effects on climate change. “There is a general awareness that the current agriculture food supply chain will not be able to provide a sustainable solution in the long term,” he told me over the phone.

There are caveats, however. Although growing bacteria using natural gas or hydrogen would technically be landless, it would require huge amounts of natural gas or energy—about 12 percent of the world’s current natural gas consumption or the energy generated by 350,000 wind turbines (there are around 340,000 turbines in operation worldwide right now).

You could use sugarcane or silvergrass as your starting material and get similar land savings, said Bodirsky, but you would only reduce greenhouse gases by about 0.1 or 4 percent instead of 7. The silver lining of using sugarcane or silvergrass is you’d avoid a lot of the nitrogen pollution that comes with growing livestock feed.

The other hurdle, according to Bodirsky, is that farmers would need time to “get used to it.” “It matters how quickly they can turn it from some prototype to some cost-competitive, large-scale production,” he said. The companies Avecom in Belgium and Calysta in the United Kingdom are currently developing the technology for commercial production. Avecom is in the pilot stages but Calysta has already scaled up their operation and is marketing its bacteria food to the aquaculture industry.

Bodirksy warned that bacteria alone won’t solve all of our environmental problems. He argued humans need to eat less meat and find better ways of using fertilizer and dealing with animal waste. But, as it turns out, bacteria might be able to help with that too. NASA is now seeing whether it’s possible to feed bacteria human poo to produce nitrogen and methane that, in turn, could be used to grow microbial protein for human consumption.

Correction: This story originally stated there are around 530,000 turbines operating worldwide right now. It's actually 340,000. Motherboard regrets the error.