Our planet is home to seven billion people. By 2050, the world's population will have ballooned to over nine billion. How to feed these people means figuring out how to feed the animals that become food.

Biotechnology company Calysta, headquartered in Menlo Park, Calif., thinks one solution involves harvesting edible protein from microbes that eat methane.

Today the company announced a partnership with Cargill, a food and agriculture company based in Minneapolis, Minn., and plans to build a gas fermentation facility on Cargill's property in Memphis, Tenn. Once the plant begins operations in late 2018, it will produce 22,000 tons of FeedKind protein. By 2020, the company wants to raise that to 220,500 tons.

"The first customers are expected to be feed manufacturers serving the fish farming industry," a spokesperson at Calysta told Seeker.

Worldwide demand for farmed fish is up. According to the Earth Policy Institute, farmed fish production by-passed beef in 2013 and it continues to rise. Feeding farmed fish remains an enormous challenge because some of the favorites, like salmon, eat only fish. But it takes two pounds of fishmeal to make one pound of salmon. Knowing this, producers have already begun to supplement feeds with vegetable matter, like soy, but it doesn't agree with a salmon's belly and can cause inflammation that leads to disease.

Calysta's FeedKind protein could be one way to feed not only farmed fish, but also cows, pigs and even household pets.

If the idea of creating food from microbes, specifically Methylococcus capsulatus bacteria, that eat methane — a gas normally associated with landfills, cow burps and manure, sounds unpalatable — you're not alone. But consider for a moment that methane is a carbon compound and that humans are carbon-based lifeforms. We are carbon; we eat carbon.

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Instead of raising these organisms on industrial-scale farms that require thousands of acres of land and millions of gallons of water, Calysta will grow these microbes in bioreactor vats. The gas fermentation technology was originally invented by Statoil, a Norwegian oil and gas company, but then in 2014, Calysta bought the patents to that technology and has been refining the process ever since.

Here's how it works: the microbes, which have not been genetically modified, are added to the bioreactors along with methane, air and other microbes that eat up any of the waste products not essential to the process. Ammonia is also added because it reacts with the carbon and hydrogen in the methane in a way that produces the amino acids that make up the proteins.

As the microbes eat away at the methane, they mature, multiply and divide as single-celled creatures are wont to do. Eventually they're ready to be harvested and at that time, each organism is more than 70 percent protein by weight. Not bad. After harvest, they're dried, powered and turned into pellets.

Feeding these pellets to farmed fish and livestock has already been approved in the European Union, and this past September Calysta set up a factory in Teesside, U.K., but Calysta will have to get the same approval in the United States. Until then, the plant in Memphis will sell FeedKind pellets to fish farmers in Asia and Europe.

At the moment, the environmental benefits of producing FeedKind protein has mixed results. The cheapest source of methane doesn't come from renewable sources, such landfills, farms with excess manure or anaerobic digesters. It comes from the natural gas industry.

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An assessment conducted by Carbon Trust, an independent firm in London, U.K, that helps businesses develop low carbon strategies, showed that that FeedKind protein has a carbon footprint that's higher than other feeds meant for farmed fish.

"However carbon is not the only thing to bear in mind," said Tom Cumberlege, senior consultant at Carbon Trust.

When he and his fellow analysts looked at how much water and land FeedKind protein required, it was a different story.

"It has a very favorable low water footprint compared to a lot of other feeds that go into fish food," Cumberlege said. "Land use is minimal because essentially it's a factory as opposed to fields used to grow crops."

In additional to assessing the current scenario, Cumberlege and his team also looked at the FeedKind's potential environmental impact. If they sourced natural gas from renewable sources and got electricity from renewable energy sources, they carbon footprint would be even with conventional feeds. And still the land and water use would be lower.

They could take it one step farther, too. Carbon capture technology.

"If carbon capture storage becomes more of a credible technology, than this could be become a negative footprint," said Cumberlege.

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