At a facility in Nebraska, White Dog Labs' massive fermenters will soon hold bacteria by the ton, each of which will be busily converting sugar into more of themselves. After being dried out and filtered, the bacteria will be a protein-rich food source with a salty, mildly buttery taste.

"It's actually pretty good on popcorn," says Bryan Tracy, CEO of Newark-based White Dog Labs. But these bacteria aren't meant for humans, at least not yet. Instead, they are bound for the gullet of farm-raised salmon.

Tracy's company has recently signed a deal with Cargill, a major supplier of fish feed, for his company's bacterial food, called ProTyton. It's helping White Dog Labs build that facility, which is located inside an ethanol plant in Sutherland, Nebraska. It's slated to be producing ProTyton, mainly for Cargill, by mid-2020.

The single-celled feed is both a critical source of protein for salmon, and, in its live form, can aid in digestion for people and their pets.

The deal promises to give White Dogs Labs a small role in satisfying the rising global demand for meat. Because wild-caught fish can't meet that pressure, farm-raised fish promise to be one potential solution.

"Yes, we want to be a part of that solution space, to sustain the health of our planet," Tracy says.

At the same time, he knows that Cargill isn't buying ProTyton because it fits a narrative of sustainability. They have to be economically viable, competitive with other protein sources.

There are more opportunities to come. The Nebraska plant is expected to be just one-tenth the size of White Dog Labs' full-scale production in coming years. Tracy also plans to expand the company into the pet-food markets and eventually into human health.

The public is increasingly aware of how our microbiome - the diverse types of bacteria that inhabit our body - shapes our health. Tracy believes that's creating opportunities for companies like his to offer digestive supplements to the millions of Americans who struggle with symptoms like abdominal pain and constipation.

First, though, come the fish.

Bacteria as opportunity

Bryan Tracy sees bacteria differently than most people. Instead of a pathogen to exterminate, they're a resource to cultivate.

"If I wiped out all the bacteria from your body, you'd die, because we are degenerates," he says.

[caption id="attachment_169104" align="alignleft" width="500"] Bryan Tracy, CEO of White Dog Labs presenting new tech for developing bacteria-based proteins. | Photo by Eric Crossan[/caption]

It's a provocative word, but he chooses it with care. We're degenerates because we can't make all the essential compounds we need to live. We need bacteria.

Tracy started out working with microorganisms as an undergrad at North Carolina State University while working at the large biotechnology company Novozymes.

Bacteria are like little factories, he explains, turning an input (usually sugar) into a finished product, which is sometimes another chemical and sometimes the bacteria itself. In yogurt, bacteria turn the sugar in milk (called lactose) into lactic acid, causing the milk to partially clot.

Globally, ethanol production is the largest industrial use of microorganisms. Tracy began his entrepreneurial work in the field, co-founding a company called Elcriton. It genetically engineered bacteria that made biofuels and other chemicals. But the decline in oil prices sapped the economic imperative of oil alternatives.

In 2011, White Dog Labs acquired Elcriton, which continues to produce technology to make some biochemicals. But the company has shifted its priority focus to animal nutrition products.

The latest opportunity to harness microorganisms is fueled by the rising global middle class. As their incomes rise, so does their demand for meat. Most wild sources of fish are fully exploited, so farm-raised fish, called aquaculture, can satisfy much of that demand.

"Much of the shrimp, salmon and catfish eaten in the U.S. will be from aquaculture," Dave Robb, sustainability manager for Cargill's aqua nutrition business, said in an email interview. "Aquaculture provides a predictable source of seafood, like livestock - and crop-farming."

However, much of the industry has kept their stocks fed with wild-caught fish.

"You're catching fish to feed fish you're farming," Tracy says. "That's not sustainable."

Cargill says it is working to improve sustainable management of its fisheries to provide long-term sources of fishmeal and pair them with land-based food like ProTyton.

Some of the most popular fish, including salmon, are carnivores with high protein demand. That's where Tracy's company comes in. So what is ProTyton, exactly?

A single-celled food joins Cargill's "˜portfolio'

The bacteria grown by White Dog Labs is called clostridia, and it's one of the most recent varieties to be domesticated, so to speak. Earlier strains of bacteria, like E. coli, were mainly chosen because they thrive in a lab, though the advent of DNA sequencing has helped scientists learn what actually grows in our guts, Tracy says.

[caption id="attachment_169103" align="alignright" width="501"] The final product that wil be incorporated into Cargill's fish feed. | Photo by Eric Crossan[/caption]

"We're going against the grain but have a strong scientific basis to justify doing this," he says. "We have an awesome opportunity to explore those organisms in the past that were unculturable."

For its uses in fish feed, clostridia were chosen for their high protein content.

Once they are removed from storage tanks and dried out, clostridia resemble corn meal, though somewhat finer. Clostridia is about 80% protein, making it a particularly nutritious element in a salmon's diet.

As it will make up perhaps 5% to 10% of salmon feed by weight, ProTyton is somewhere between a spice and a main course. But the proper culinary analogy is with baking, Tracy says. As a baker mixes together flour, butter and sugar to make a cake, Cargill will use ProTyton as one ingredient among several to create a feed that's most efficiently converted to fish.

Cargill is pursuing multiple innovative fish-food partnerships. In June, it announced a deal with the French firm InnovaFeed, which feeds farming byproducts to grow black soldier fly larvae to create an insect-based fish food. This larger "portfolio of nutrients," as Cargill calls it, helps protect its customers (Cargill sells fish food but doesn't directly raise fish) from sudden price movements, Jeff Kazin, director of risk management and sourcing for Cargill's aqua nutrition business, said in an email.

But innovation doesn't necessarily lead to business success.

Some of these advances that aim to make the industry more sustainable will, in the short term, lead to higher prices, said Robb, the Cargill sustainability manager.

"But if the value chains, and ultimately the consumers, truly value sustainability over the traditional focus of cheap food at high volume, the industry will be able to change," he wrote.

One option is to charge more for sustainable salmon. A company called Verlasso is commanding higher prices for salmon it says is farmed in a more environmentally conscious way.

Perhaps the most tantalizing part of the White Dog Labs story is its potential scope. Fish are only the beginning.

From fish to humans

Enlisting bacteria as a nutritional supplement has promise in pet food and human medicine, though the model is different from fish feed.

Farmers choose fish food to maximize weight gain, though pet owners choose food for very different reasons. But clostridia could be promising for humans and pets, as well.

Though its high protein content is helpful for animal feed, clostridia produce butyric acid, which has a number of digestive benefits. In these applications, clostridia will be a live supplement.

Tracy says he doesn't plan on selling bacteria as a medicine. Instead, he's looking at a niche of savvy customers who see the benefits clostridia could offer.

"I'm saying I know a healthy gut would have a lot of this so here you go," he says of clostridia.

That said, this bacterium has promising applications for human health, including the prevention of Clostridium difficile infections, which kill an estimated 29,300 Americans per year.

For all their reputation, bacteria are exemplars of sustainability. Give them some basic building blocks and a carbon source and they can make their own food. Harnessing them as  microscopic bacterial factories may be again helping scientists push the boundaries of sustainability. 

Clostridia's benefits - its high protein content for fish and digestive benefits for pets and people - could help push boundaries in humanity's long collaboration with bacteria. 

By Dan Linehan
Contributing Writer