Precision fermentation — feeding the planet with science?

It's a sci-fi cliche that, in the future, we'll eat synthetic food grown in vats. This idea repeats across decades, like in The Matrix:

In most of these stories, vat-grown food is a sludge that's nutritious but tastes horrible. Sometimes there's a story reason why it's not more appetizing, but the real reason is that it reflects our ambivalence about technology.

We rely on technology, but we don't trust it. We believe nature has some vital essence that humans can never capture; that the things we create will always be pale imitations. This is the old dualist idea that comes from religion, and it has a tenacious hold on us.

But technologies already exist that bridge the gap between humanity and nature. You probably eat and drink things that come out of vats, and they're not unappealing slime. They're flavorful foods and beverages like wine, beer, cheese, sourdough, chocolate, yogurt, pickles, soy sauce, or kimchi—all produced by fermentation.

Fermentation is the oldest biotechnology. We feed bacteria and yeast molecules they like — sugar, for example — and they convert them into molecules we like, like alcohol. People have been taking advantage of these microbes for as long as civilization has existed. It's a process that's neither purely natural nor purely technological.

Now that we know about DNA, we can improve this process to better serve our ends. We can take microbes, splice in genes for proteins or other organic compounds, let them grow and multiply, and collect the desired product. This is called precision fermentation, and it has the potential to transform the way we eat.

From insulin to CRISPR

Precision fermentation isn't a brand-new technology. It's existed for decades.

Traditional cheesemaking relies on a substance called rennet, which curdles milk so it can be separated into curds and whey. In the past, rennet was harvested from the stomachs of calves. However, since the 1990s, rennet (technically, its key enzyme, chymosin) has been made by yeast. Nearly all hard cheese is made this way.

The first use of precision fermentation is even older. In 1982, the FDA approved insulin produced by bacteria. This breakthrough replaced the old method of purifying insulin from cow and pig pancreases.

In the past, creating a genetically engineered organism was laborious and expensive. Insulin, rennet and the like were ideal because they're high-value products only needed in small quantities.

However, new technologies like CRISPR have made genetic engineering almost trivially easy. With this power, we're about to see an explosion of new uses. Some of them may soon be on supermarket shelves.

Cow-free ice cream and chicken-free eggs

In fact, foods made with precision fermentation are already on sale. Impossible Foods, the plant-based meat company, uses genetically engineered yeast to make heme, an iron-bearing protein that gives meat its color and savory taste.

We've also engineered microbes to produce dairy proteins, like whey or casein, identical to those in milk. In this way, we can make milk, cheese and yogurt that don't come from animals. A biotech company called Perfect Day was one of the first, but competitors are sprouting up.

The same goes for eggs. Microbes can produce ovalbumin, the protein in egg whites, without chickens. Another startup, The Every Company, makes animal-free egg whites for industrial baking and other uses.

The technology isn't limited to imitating existing foods. The Finnish company Solar Foods is pioneering a food product derived from hydrogen-eating bacteria. All the microbes need is water, carbon dioxide, electricity, and small amounts of trace elements. The end product, which the company calls Solein, is 70% protein and contains all the essential amino acids.

Of all the foods made with precision fermentation, Solein comes closest to the sci-fi vision. But it's not an edible goo. It's a nutritious, mild-tasting flour that can be blended into existing recipes. One can imagine how it could be a boon for poor or famine-stricken regions. Every town could have its own bioreactor, needing only water and solar panels to feed its people. When a Russian dictator is waging war on one of the world's breadbaskets, you can see the appeal.

Saving the planet from ourselves

The obvious advantage of this technology is that it's cruelty-free. We can eat the foods we enjoy without having to cage or kill animals.

However, the benefits to the planet could be even greater. By U.N. estimates, one-third of Earth's arable land is used to grow food for animals, with all the pollution and habitat destruction this entails.

Brazilian rainforests are cut down for cattle ranching. Water from the dwindling Colorado River is diverted to grow alfalfa for animal feed. Industrial feeding operations produce lakes of toxic manure. Animals crammed into crowded warehouses need heavy doses of antibiotics to keep disease in check, which breeds resistant bacteria.

And then there's the climate. Cows belch out methane, a potent greenhouse gas. Scientists estimate that one-seventh of all greenhouse gas emissions come from livestock.

As developing countries get richer, their growing middle classes will aspire to a Western diet. This means the demand for meat, dairy and eggs is only going to increase. There's no way we can satisfy it using conventional methods without ravaging the planet.

This is where precision fermentation comes in. In theory, it should be able to produce protein with less space, energy and water than livestock—even less than conventional crops like soy. According to George Monbiot:

One paper estimates that precision fermentation using methanol needs 1,700 times less land than the most efficient agricultural means of producing protein: soy grown in the US. This suggests it might use, respectively, 138,000 and 157,000 times less land than the least efficient means: beef and lamb production. Depending on the electricity source and recycling rates, it can also enable radical reductions in water use and greenhouse gas emissions.

A life-cycle analysis by Perfect Day asserts that precision fermentation could reduce the dairy industry's energy use by 60 percent, carbon emissions by 97 percent, and water consumption by 99 percent.

These are incredibly hopeful numbers—if they prove to be true. So far, that's the biggest if.

Capitalism versus transparency

The biotech companies bringing these products to market aren't objective. They want to make money, and eco-conscious consumers are their target audience. They have an incentive to exaggerate the environmental friendliness of their methods and to downplay the resources they consume.

Indeed, many of these companies keep their technology secret. Under capitalism, that's necessary to attract investors. You don't have a competitive advantage if anyone can copy you. However, it also means they lack transparency. We don't know what inputs they need to produce protein on a large scale, or what waste might result.

Dr. Julie Guthman, a professor of social sciences at the University of California, Santa Cruz, studies the social impacts of alternative food technology. Here's how she put it in a published paper:

Silicon Valley food tech entrepreneurs aspire to bring a new food system into being and convince their audiences that this food future is both better and achievable. Nevertheless, their representational practices make it difficult, if not impossible, for the public—or anyone really—to meaningfully assess the promises and their potential consequences, much less hold their proponents accountable to anything but pecuniary concerns.

Without hard data, we can't be sure how this technology compares to raising livestock. It's plausible that precision-fermented protein is better for the planet. But to do science, we need evidence, not just assumptions.