杏吧原创

BACK IN 2014, bioengineer Ryan Pandya had a demoralising encounter with a bagel. It wasn鈥檛 so much the bagel itself as its filling, a 鈥渂land and runny鈥� substance made from soya which was supposed to resemble cream cheese. Pandya was a recent convert to veganism and was struggling to give up dairy products. But when life dealt him bad cream cheese, he made ice cream.

Today, Pandya鈥檚 company Perfect Day is at the vanguard of a food revolution. It makes and sells milk, but has no cows. Its farm is a bioreactor in which it cultivates microorganisms genetically engineered to secrete milk proteins. The proteins don鈥檛 resemble milk 鈥� they are milk, identical to the real thing. Perfect Day hasn鈥檛 quite cracked cream cheese yet, but has arguably gone one better: ice cream. It is the only such milk company to get a product on the market so far, but won鈥檛 be the last.

The past couple of years have been an absolute beanfeast for people like Pandya who want to give up animal products but also don鈥檛 want to give them up. Plant-based burgers from companies such as Impossible Foods and Beyond Meat have proved that vegan 鈥渕eat鈥� can get pretty close to the real thing. Cultured meat 鈥� actual muscle tissue grown from stem cells 鈥� is being and is inching closer to the mass market.

But between these two extremes, a third revolution has quietly been brewing. Quite literally. It is called 鈥減recision fermentation鈥�, which means using genetically engineered microorganisms to produce animal products. Milk is where most of the action is right now, but is by no means all there is on the menu: think of an animal product that isn鈥檛 meat, and somebody somewhere is working on brewing it up.

Of course, microbial fermentation is hardly a new food technology. Bread, cheese, yogurt, beer and wine were all invented millennia ago, and derive much of their taste and texture from the waste products of yeasts and bacteria eating their raw materials. Ditto sauerkraut, kimchi, miso, kombucha, tempeh and more.

In 1990, these traditional ferments were joined by a new technology, when the US Food and Drug Administration (FDA) , aka rennet, for making cheese. This enzyme curdles the milk protein casein, and was once exclusively harvested from the stomachs of unweaned veal calves. By the 1970s, there was a , so biotech companies raced to use genetic engineering to produce chymosin in bacteria or yeasts. Pfizer won. Today, about 90 per cent of rennet is made by genetically modified microorganisms.

This 1970s technology 鈥� clone the gene and stick it into a bacterium or yeast 鈥� is still the basis of precision fermentation, but is now coming into its own. 鈥淲hat can we actually make with fermentation?鈥� says Nate Crosser at the alternative proteins investment incubator Blue Horizon in Zurich, Switzerland. 鈥淭he answer is, essentially whatever we want. If an animal can make it, it鈥檚 likely that we can produce at least a relatively faithful facsimile with fermentation.鈥� Many companies are busy making good on that promise, developing all manner of animal products such as egg proteins, and various additives for cultured or plant-based meat, including fats, collagen and the blood protein heme.

But the real action is happening with milk. According to a for his former employer, the Good Food Institute (GFI) in San Francisco, about three quarters of precision fermentation companies are working on the white stuff. 鈥淭here is a real revolution going on here,鈥� says biotech investor Jim Mellon, a leading backer of precision fermentation and author of Moo鈥檚 Law: An investor鈥檚 guide to the new agrarian revolution. Many of the milk companies will follow Perfect Day and get products on the market this year, he predicts.

鈥淚f an animal can make it, it鈥檚 likely that we can make it too鈥�

Precision fermentation is part of a broader industry called cellular agriculture, which is best known for cultured meat and seafood. Firms like Perfect Day are often spoken about in the same breath, but their technologies are actually very different. 鈥淢ilk is simpler,鈥� says Josh Milburn at the University of Sheffield, UK, a philosopher who researches human-animal relations. For meat, the starting point is stem cells extracted from the animal, which are cultured in a growth medium to generate muscle plus sometimes fat and connective tissue. Milk, on the other hand, is just a mixture of biomolecules suspended in water, and hence a lot easier to recreate.

To a first approximation, milk is just six proteins 鈥� four caseins and two wheys 鈥� plus fats, sugars and minerals, all suspended in water. Right now, most of the fermented dairy companies are focusing on protein components of milk rather than whole milk. Perfect Day, for example, produces whey proteins in a fungus (Trichoderma reesei) for use as a food ingredient. This 鈥渘on-animal whey protein isolate鈥� is the 鈥渄airy鈥� component of three brands of vegan ice cream currently on sale via mail order in the US.

Maille O鈥橠onnell at the GFI has tasted one of them, made by a company called Brave Robot. 鈥淚 liked it,鈥� she says. 鈥淔riends who tried also said it really tasted like dairy ice cream in a way plant-based ice creams haven鈥檛 yet.鈥� It is competitively priced at $5.99 a pint (about half a litre). That is in stark contrast to cultured meat, where a few pieces of chicken can cost as much as a fancy steak dinner.

That is because fermentation is already a mature technology familiar to the food industry, so nobody has to invent new production processes and scale them up. Even better, nobody has to convince regulators that the foods are fit for human consumption, because they are made using microorganisms and processes that are already 鈥済enerally recognised as safe鈥�. When Perfect Day asked the FDA to approve its whey protein in 2020, the agency said yes right away.

Ice cream and beyond

In fact, says Milburn, cultured milk could theoretically be healthier than the real thing. It is produced without antibiotics or hormones and is less likely to be a carrier of food-borne infections. It can be made without lactose, which many people are intolerant to, can feature healthy fats and could be fortified with nutrients. 鈥淏ut this is all quite speculative at the moment,鈥� he says.

Ice cream is the only product on the market, but probably won鈥檛 be for long. Many other leading companies are focused on cheese. Formo in Germany and New Culture in San Francisco are concentrating on pizza toppings.

Formo ferments caseins and whey and then uses standard cheese-making to turn them into mozzarella and ricotta. Like many in the industry, its founders are driven by a desire to replace ethically and environmentally troubling animal products with guilt-free replicas. 鈥淚n the Western world, the demand for dairy products is kinda limitless,鈥� says CEO Raffael Wohlgensinger. Demand is rising in Asia too. All this is putting unsustainable pressure on the environment, but many consumers are loath to give up cheese. 鈥淭he biggest consumer pain point for flexitarians who want to get rid of animal products is cheese because plant-based products are not performing well,鈥� says Wohlgensinger.

Pizza toppings may not be everyone鈥檚 idea of the full-fat cheese experience, but Formo also has its eyes on a more sophisticated market. 鈥淲e really develop products for the cheese lovers, this is the market we鈥檙e going for,鈥� says Wohlgensinger. Formo is planning to unveil its prototypes at a tasting event in Berlin later this year, with the food prepared by Ricky Saward, head chef at Michelin-starred vegan restaurant Seven Swans. 鈥淲e focus on taste and texture. I鈥檓 very confident when I look at what we鈥檝e been able to achieve,鈥� says Wohlgensinger.

That, however, is a challenge because these cheeses derive much of their character from the whole milk, not just the protein. That would mean precision fermenting milk fat, which is the product of a complex metabolic pathway rather than a single gene. But it is work in progress. 鈥淭hat鈥檚 a definite technology development that is going on at the moment,鈥� says Wohlgensinger.

Gourmet cheeses also trade on a mysterious quality called terroir, which is a distillation of the geography, vegetation and climate where the milk was produced and fermented, plus the skill of the cheese-maker. That will be tough to replicate with bioreactor-created milk.

But such cheeses are a tiny sliver of the market, says Wohlgensinger, and if precision-fermented cheeses only eat into the mass-produced varieties it will be mission accomplished. Some food snobs will never be won over, but they should examine their consciences, says Milburn.

Animal welfare is a major issue in the dairy industry. Despite its carefully cultivated image of rural idyll, dairy farming routinely involves milking cows to exhaustion, repeatedly inseminating them, separating them from their offspring and disposing of male calves that are surplus to requirements. The dairy industry also has cow-sized environmental problems. Producing milk in a live animal is fantastically inefficient and the dairy industry alone is responsible for 4 per cent of our greenhouse gas emissions, according to the , which, as Wohlgensinger points out, is .

鈥淣o one has to convince regulators 鈥� these processes are already recognised as safe鈥�

But take the cows out of the equation and these problems vanish. Zero animals 鈥� aside from small biopsies to supply stem cells or DNA 鈥� means zero animal welfare issues. And a in Durham, North Carolina, estimated that the carbon footprint of milk made through fermentation could be as little as 1.2 per cent that of traditional milk production.

鈥淚 am very much an advocate of this technology,鈥� says Milburn, 鈥減rimarily because of my concerns about animal rights, but because of environmental impacts as well.鈥�

With ice cream on the market and cheese in development, the obvious next place to go is whole milk for drinking or putting in tea and coffee. That is a whole other challenge, however 鈥� not because of technological limitations, but because of what have been dubbed the 鈥溾��. In the EU, for example, the dairy industry has successfully lobbied law-makers to stop plant-based dairy substitutes made from oats and nuts from using the words 鈥渕ilk鈥� and 鈥測ogurt鈥�. Last year, the European Parliament voted to extend the ban to cover any 鈥渆vocation鈥� of the concept of dairy, but in May it after .

Similar barriers exist in the US, where the FDA defines milk as 鈥渢he lacteal secretion, practically free from colostrum, obtained by the complete milking of one or more healthy cows鈥�. US legislators are currently considering an of other dairy animals, and also to prohibit the application of the words 鈥渕ilk,鈥� 鈥測ogurt鈥� and 鈥渃heese鈥� to plant-based alternatives. The FDA already designates these alternatives as 鈥渘utritionally inferior鈥� and prohibits them from being stocked alongside traditional dairy products.

In the EU and UK, meanwhile, milk is defined as 鈥渢he normal mammary secretion obtained from one or more milkings without either addition thereto or extraction therefrom鈥�. 鈥淭his definition does exclude the products made via precision fermentation,鈥� says Sophie Clarke at trade body Dairy UK.

The dairy industry is right to be running scared, says Mellon. In the past two years, two of the US鈥檚 biggest dairy companies, Borden Dairy and Dean Foods, have gone bust, in part because of competition from alternative milks.

The industry has yet to start lobbying against precision fermentation, yet its aggressive pushback against plant-based alternatives is a taste of what companies like Formo can expect, says Lisa Jordan Powell at Sweet Briar College in Virginia.

Keeping abreast

But there is a market where something resembling whole milk might gain a toehold, and it has nothing to do with cows. According to the GFI, two precision fermentation firms in the US 鈥� Harmony in Boston and Helaina in New York 鈥� are working on human breast milk. Two other companies, Biomilq in North Carolina and Singapore鈥檚 TurtleTree, are eyeing the same market, but going down a different road, culturing human mammary gland cells and collecting the milk they make. This is closer to cultured meat technology than precision fermentation.

None has yet demonstrated a prototype and it isn鈥檛 clear which alternative breast is better. But the potential is huge, says Mellon . 鈥淚 don鈥檛 know how long it will take them to get on the market, but it鈥檚 not too many years off. And it鈥檚 a big market 鈥� we think over $50 billion.鈥�

Beyond that, name your animal product. Fats, collagen and blood are in development, mostly to add to cultured and plant-based meats to make their taste and texture more authentic (vegan black pudding, anyone?). Eggs too, despite whole ones being tricky because making a separate white and yolk is complex. A company called Clara Foods has already cracked the technology for fermenting egg white as a commercial bakery ingredient, although it isn鈥檛 yet on the market. Another company, MagicCaviar, has said it is working on a version of another type of egg 鈥� from fish. And there is a whole realm of non-food products out there waiting to be fermented (see 鈥�Alternative materials鈥�).

Ultimately, says Zak Weston at the GFI, success or failure will be determined by what always determines the fate of new foods: taste, price, accessibility and convenience. If precision fermentation can deliver on those, companies like Perfect Day will be creaming it in. As Milburn says, 鈥渢he proof of this pudding will be in the eating鈥�.