Okay, I’ll throw in my two cents to this question. First of all, this is not going to be a happy cow and I really hope that you don’t have a farm in real life. Honestly, there’s a reason that nobody’s even bothered to attempt biological PTFE synthesis, largely because of the amount of wince-inducing enzymes I’m going to have to use for the synthesis pathway. Sadly, this setup certainly fails the ‘reality-check’ tag.
Curiously, it’s possible to construct a pathway to PTFE of which the only real diet change would be the addition of fluorite. I’ve sketched out this pathway below, which might be good to refer back to as we walk through it. Essentially, to get PTFE we need tetrafluoroethylene (TFE). TFE is made from chloroform and hydrofluoric acid (HF). To get HF, we need fluorite and a strong acid - sulfuric acid is what’s used industrially, but I’m going to argue that hydrochloric acid (HCl) could work alongside a catalyst to simplify the pathway. To get chloroform, we can mix ethanol and bleach. Of course, bleach isn’t a great food for living things so we should also synthesize that from ozone and NaCl.
The majority of the starting ingredients can already be synthesized biologically from normal feed, specifically ethanol, NaCl, and HCl. Ozone could be obtained in parts-per-billion quantities from normal air, which means that the only base ingredient we need to add to their normal food is fluorite.
Now, we should note that there are a couple immediate problems with this pathway. First of all, many of these reactions don’t occur at room temperature and instead require 500+K to occur. However, if we invoke the mystical power of enzymes we can reduce that activation energy to something like internal body temperature.
I use “mystical” to describe enzymes here, but they’re not magic or handwavium - just biological catalysts. Catalysts reduce the activation energy of a reaction by organizing, stabilizing, and orienting the molecules in such a way that it’s no longer brute-force random noise (high temperatures) that allow a reaction to go to completion, but instead a choreographed dance.
Second of all, most of these ingredients are awful. I’ve compiled here a list of the warnings on Wikipedia about various chemicals we’re using:
Ozone is one of the greatest oxidisers we know of, which is why it’s so dangerous. We can smell it at ~1-2 ppb (parts per billion), and it’ll start to damage us at ~100 ppb, with an LC50 of ~50 ppm (parts per million). Given these restrictions on the concentration of one of our reactants, this may be a very slow reaction even when operating at near-lethal concentrations.
Bleach is used to kill things. Plain and simple. We use it in bio labs to get things really really clean, and after we do so we usually label them “not to be used with sensitive organisms”. Here’s the warnings from Wikipedia:
“... ingestion of bleaches can cause damage to the esophagus and stomach, possibly leading to death. On contact with the skin or eyes, they may cause irritation, drying, and potentially burns. Inhalation of bleach fumes can damage the lungs.”
Chloroform is also pretty terrible for humans - that’s why we pass out when we sniff it, and why it can kill us if we consume more than a thimbleful of it. Here’s some Wikipedia warnings:
”Prolonged dermal exposure can result in the development of sores as a result of defatting.” “Accidental splashing into the eyes has caused irritation.” “... causes depression of the central nervous system (CNS), ultimately producing deep coma” “use of chloroform [for anesthesia] has been discontinued because it caused deaths due to respiratory failure and cardiac arrhythmias”
Acids are not great for humans. They won’t melt you (well, most of them) but they can quickly ruin your day. Here, we’re talking about some of the worst. Sulfuric acid is pretty terrible stuff and hard to synthesize, so I opted for the tamer hydrochloric acid (HCl). It’s possible that you could synthesize sulfuric acid biologically, but HCl and an enzyme will probably work just as well together. However, it’s worth noting that HCl is still pretty terrible. We humans synthesize this stuff naturally for digestion in the stomach, where it constantly eats away at our mucus linings and causes heartburn and ulcers when it escapes.
But neither of those acids compare to hydrofluoric acid (HF). This stuff has been described as “movie acid” because it’ll eat through, like, everything. Metals, organics, whatever. The first video that pops up when you search for HF is “flesh eating acid”. The OP didn’t include HF in his acid cows because even PTFE is permeable to it. Please sir, may I borrow a little of that unobtanium?
Finally, tetrafluoroethylene (TFE) is not fun stuff either. I couldn’t find any specific hazards associated with it besides “weak carcinogenic effects” but it’s given 3/4 for health hazard, 4/4 for flammability, and 3/4 for reactivity by the NFPA, better known as the “fire diamond”.
And all of the above assumes that you’ve managed to insert suitable genes for these various, custom-designed enzymes into their genetic code in such a way that they’re properly duplicated, transcribed, and translated. Most enzymes (proteins) aren’t stable under strong acids, instead hydrolyzing into individual amino acids... which also aren’t stable under low pH. Also, DNA falls apart under low pH.
Fun, right? Your genetic engineers probably hate you and have all quit. You’ve turned your cows into essentially fume hoods for synthetic chemistry, and they’re unlikely to be much more than a pile of chemicals after a while. And they all have cancer. Oh, and while they were alive, you fed them rocks.
Cool question, murderer!
- a vegan somewhere, probably
You can pick whatever tissue you want to line with PTFE. I initially thought that the stomach would be a good choice for this because it’s already dealing with acids, but the substances we’re working with are so far beyond “normal” acids that the 5-6 pH unit difference body tissue and stomach tissue is blown out of the water by the ~20 pH unit difference between body/stomach tissue and fluoroantimonic acid. If your genetic engineers have succeeded at all of the above, they’ll have no problem turning the cow’s head or hooves into acid cauldrons. Which really begs the question of why we’re using cows at all.
So, the problems listed above arose from the creation of a single cow. You’re interested in making 264 million of them. I can not express strongly enough how much I would advise against this course of action. Problem #1 being that we’d actually run out of rocks to feed them. We’d also run out of ozone and have to synthesize that artificially, which the environmentalists will not be happy about because it’s a major pollutant at ground level. Heck, we’d even put a dent in the world ethanol supply.
Biologically synthesized PTFE fails the ‘reality-check’ really hard. However, there are some options if you’re willing to be a little flexible.
Biological silica production is a real thing. Diatoms make their frustules out of glass by secreting silica nanospheres which they then glue together. Glass is vulnerable to erosion by fluoroantimonic acid, but so is our stomach mucus vulnerable to normal HCl -we just secrete it continuously. I’m also confident your genetic engineers would be happier to insert eukaryotic diatom genes into a eukaryotic cow than archaeal bacterial ones.
As pointed out in a comment, waxes might also be a way to store these acids. Again, they’re not immune to the results but constant secretion might also solve that problem. In fact, they’d probably react with the acids themselves and substitute fluorines in place of the hydrogens, which would create a structure very similar to PTFE anyway. Even better, cows already produce fats which would simply need to be elongated/saturated, or you could borrow some honeybee genes (wow, same kingdom even! Maybe you’ll be able to re-hire some of your old engineers now that you’re making such reasonable requests) and do wax production directly.
(Shoutout to the Answer Sandbox for some help developing this answer!)