Precision fermentation and the insulin precedent

Why Food Made by Microbes Wins First Where Animal Sources Are Scarce, Not Where Cows Are Plentiful

Precision fermentation uses engineered microbes, such as yeast, fungi, or bacteria, to make one specific protein that once came only from animals. This article is about futurism and about moving food and medicine from scarcity toward abundance. Its thesis is simple: the two biggest successes of this method so far, human insulin and the cheese enzyme chymosin, won because the animal source was scarce and only small amounts of the molecule were needed. Bulk milk proteins face the opposite situation, because cows already make them in huge volumes at low prices. Reading the insulin precedent correctly tells researchers, investors, and policy makers where abundance from microbes is likely to arrive first, and what has to change before it reaches everyday protein.

Two quiet victories most people never noticed

Insulin from bacteria instead of glands

For about sixty years, people with diabetes depended on insulin taken from the pancreas glands of cows and pigs. The Food and Drug Administration (FDA) history of insulin describes how fragile that supply was. By 1981, making one pound of insulin required 8,000 pounds of glands from 23,500 animals, and that pound was enough to treat only 750 patients for one year. Gland supply fell during the 1970s while meat prices swung widely, so the price and availability of a life-saving drug rose and fell with the slaughterhouse.

In 1978, scientists at City of Hope and Genentech produced human insulin in bacteria, and on October 28, 1982, the FDA approved Humulin after five months of review. It was the first approved medical product of any kind made with recombinant DNA. The supply problem that had shadowed diabetes care for decades stopped being a question of how many animals were killed.

Chymosin and the cheese already on your plate

Cheese makers had their own scarcity problem. Rennet, the enzyme mixture that curdles milk, traditionally came from the stomachs of young calves. In March 1990, the FDA affirmed that chymosin made by fermentation with a modified strain of the bacterium E. coli K-12 was generally recognized as safe, in response to a petition from Pfizer. The Los Angeles Times reported at the time that it was the first genetically engineered product approved for human food, and that one ounce of the enzyme could thicken 50 gallons of milk.

According to the McGill University Office for Science and Society, more than 80 percent of cheese in North America is now made with chymosin produced this way. Because the enzyme breaks down during cheese making, none of it remains in the finished product. One of the largest shifts in the history of food production happened with almost no public fight.

The pattern behind both wins

Insulin and chymosin share three features that are easy to miss.

• The animal source was scarce. Glands and calf stomachs are by-products of slaughter, so supply could not grow on demand.
• Each unit of product needed very little of the molecule. A small amount of chymosin curdles a large vat of milk, and a person needs only a small amount of insulin each day. Even an expensive microbial process could compete.
• The value per kilogram was high. When a molecule is rare and essential, buyers can pay for a new process while it is still improving.

Under those conditions, fermentation does not need to beat a cow. It only needs to beat a shortage.

Why bulk milk proteins are the hard case

Whey and casein reverse every one of those features. They are not scarce, they are needed by the kilogram rather than by the gram, and they sell at commodity prices. A 2025 Good Food Institute (GFI) review of cost models found wholesale casein at about 8 to 11 dollars per kilogram and whey proteins from about 1.2 to 17.7 dollars per kilogram depending on type and purity. Published production cost estimates for precision fermentation proteins ranged from under 20 dollars to about 14,000 dollars per kilogram, and the authors noted that public data are thin. A 2025 review in the scientific literature put recombinant milk protein costs at about 210 to 310 dollars per kilogram, compared with about 15 to 25 dollars for conventional dairy protein.

Food producers have shown that a microbe can make whey that matches the cow version. The FDA responded with no questions in 2020 to a notice for beta-lactoglobulin, the main whey protein, made by the fungus Trichoderma reesei. Safety and sameness were never the main barrier. Price is.

Where the insulin rule points next

If the pattern holds, the first wave of food abundance from fermentation will come from milk and egg molecules that are scarce in the animal source. The GFI review lists lactoferrin, a minor whey protein, at market prices of 250 to 1,000 dollars per kilogram, which makes it an attractive early target. A GFI Europe cost model for alpha-lactalbumin, another whey protein, found that a fermentation version may already compete in infant and sports nutrition, while general foods still need further cost reductions.

This is the insulin path again: start where the animal is a poor factory, learn to run the process well, and let scale and experience push costs down toward commodity products later. Every high-value product that sells also pays for strain improvements, operator training, and equipment that a later bulk protein can use.

The bottleneck is factories, not ideas

The constraint that most limits this path is physical capacity. A 2025 GFI report on contract manufacturers quotes the Illinois Fermentation and Agriculture Biomanufacturing (iFAB) Hub, which received a 51 million dollar federal grant in 2024: demand far exceeds capacity for pilot fermenters of about 1,000 liters and demonstration fermenters of about 20,000 to 75,000 liters, made worse by a shortage of trained workers. GFI also reports that companies often finish one round of testing and then cannot find open pilot capacity for the next round, which slows learning.

Feed is the other constraint. Synthesis Capital notes that most producers feed their microbes glucose from crops such as corn and wheat, and that this feedstock can make up more than half the cost of each kilogram of product. Food made by microbes still depends on farms until lower cost carbon sources work at scale.

Honest limits

• Public cost data are sparse and vary by orders of magnitude, so any single price claim should be treated with caution.
• The insulin comparison is an analogy. Medicines and foods face different rules, margins, and buyer expectations.
• Insulin abundance in production did not guarantee low retail prices for patients. Production abundance and fair access are separate problems.
• Rules on labeling, naming, and approval differ between countries and can change quickly.
• Nothing here is a recommendation to buy any product or invest in any company.

Lessons for abundance builders

The practical lesson is to ask, for any proposed microbe-made food, whether the animal source is scarce and how much of the molecule each serving needs. Where the answers are scarce and small, success may be close. Where the answers are plentiful and large, the real work is shared pilot plants, a trained workforce, and lower cost feedstock. Public and nonprofit funding for open pilot capacity may do more for food abundance than another startup chasing commodity whey.

Discussion questions, essay ideas, and learning related AI prompt ideas

• Explain why insulin and chymosin succeeded with fermentation long before milk proteins, using scarcity, dose, and value per kilogram.
• Compare the scarcity of animal glands in the 1970s with the current supply of whey, and describe what that comparison predicts.
• Argue whether public money should build shared pilot fermentation plants that any company or university can rent.
• Describe how the gap between abundant insulin production and high insulin prices could repeat with fermented foods, and how it could be avoided.
• Identify three molecules in milk or eggs that are scarce in the animal source and assess which might follow the insulin path next.
• Explain why chymosin entered most cheese with little public debate while newer fermented foods draw more attention.

See also

• Microbial protein
• Cultivated meat bans
• Why vertical farms fail
• Pig organs and organ scarcity
• Synthetic biology
• Biotechnology
• Post-scarcity economy