Methane-guzzling bacteria could feed fish, pets, even people

The small tank of pink liquid bubbling away on a lab counter looks a little like a vat of Pepto-Bismol.

Even if you didn't know if was full of Methylococcus capsulatus, a type of bacteria, you probably wouldn't be tempted to make a meal of the frothy soup. But it could make a tasty treat for a salmon.

"These are the organisms themselves — single cells — growing in very high density, so there's lots and lots of cells in that tank," says Lori Giver, vice-president of biological engineering at Calysta, a biotechnology company based in Menlo Park near San Francisco.

Normally, she says, you'd find these microbes in the wild munching on methane from decomposing vegetation. "They've evolved over the years to use that as their sole source of carbon," Giver says.

In this lab researchers pipe methane into the tank to feed the bacteria. Then they kill them with heat and dry them, creating a fine pink powder.

The company shapes the powder into pellets, and there you have it: fish food.

"The problem with aquaculture" says Alan Shaw, Calysta's president and CEO, "is you have to feed fish other fish before we can eat them. That's not sustainable … we're basically tapping this planet dry."

Calysta's fish food is more than 70 per cent protein. And the bonus: the bacteria dine on methane that can be captured from garbage dumps or fracking operations.

"There's a lot of waste methane," Shaw says. "If we can trap that … every ton of methane we can sequester, we're actually saving the planet as well."

Calysta hopes to make a lot of money in the process. Even though this bacteria-based fish food isn't yet approved in North America, it is in Europe.

Companies like Monsanto are putting billions of dollars into research. In less than 10 years, the microbiology culture market is expected to reach $8 billion, Shaw says.

"Carbon is getting cheap, inorganic carbon is flooding the marketplace … the possibilities of this are really becoming endless," says industrial microbiologist David Bressler of the University of Alberta.

"Agriculture is facing a monumental challenge: how to feed nine billion people in the next decades."

By using bacteria, Bressler says, "we can create high-value protein without overburdening the environment."

These microbes can feed not just fish but livestock, pets, and even people. Bressler's lab is turning yeast and bacteria into food products like Omega-3s and sweeteners.

But many people think the only safe place for bacteria in food is in yogurt or cheese. That means the companies Bressler works for, whose names he keeps confidential, have to overcome the perception that such products are gross or even harmful.

"This is an important discussion at the forefront of the industry," Bressler says. "It's at the core of everything we do." 

He acknowledges there are potential risks because microbiologists are no longer limited to naturally available strains of bacteria. 

"What's changed now in the last five to 10 years through genomics is that we understand biochemical pathways in a way that allows us to write DNA," Bressler says. 

This raises the potential dangers of genetically modifying microbes.

"The problem you get in any new area, though, is that you get a lot of people that jump in. Early companies in any space tend to make a lot of claims that they can't validate," Bressler says.

He says some weeding out needs to take place in order to protect consumer confidence in these kinds of new products.

"As we look at each modification, each organism … do we understand what we're doing, are we doing it in a controlled setting and are we sure we're doing it in an ethical way?"