Milk protein costs around 95 kg of CO2-equivalent emissions per kg of protein, which is apparently what was used in the production of this plastic [1]
[0] https://www.sciencedirect.com/science/article/pii/S002203022...
[1] https://ourworldindata.org/grapher/ghg-per-protein-poore
https://en.wikipedia.org/wiki/Whey_protein#Microbial_product...
It's not theoretical either. You can buy vegan dairy products made from this method today.
In addition, you'll need more cleaning/sterilization/mixing. I'd guess that it's lower, but I wonder how much lower.
And then there's the other products that generally get thrown into the mix to make up for things like missing fats. For example, a vegan cheese based on bacteria will often include coconut oil, probably to get the same fat profile.
Whey is an interesting product in general because it's a waste product of cheese making.
Feed efficiency is critical when doing these calculations as cows inherently need energy to survive not just produce milk. As such even if you use the same crop two different sources of protein can have wildly different levels of CO2 emissions embedded in their creation. https://en.wikipedia.org/wiki/Feed_conversion_ratio
You can't just throw in grass clippings into a vat and get whey. You can throw grass clippings into a cow to get milk (though, TBF, I dislike grassy milk).
That’s a lot of room for improvement which then means far less labor on growing crops.
And, as much as some powers try to convince us, not everything can be reduced to carbon footprint.
So it's not out of the question we could scale that up to meet plastics demand.
That was before multi-billion-dollar companies came up with marketing strategies that manipulated people into not understanding what milk was, instead making them believe that milk is whatever they tell people.
Usually, the reaction to this is "Well, language and the meaning of words change." ... Sure, but that argument comes in complete ignorance of the fact that it only happened, because people with too much money and power can manipulate millions into believing whatever these millions of people are supposed to believe.
Thus now anything can be milk, as long as some profit-oriented company decides that people shall call it milk.
This practise has become the norm to a degree that people will not only generally accept it, but also generally defend it. Pure madness.
"Almaund mylke" is all over medieval cookery manuscripts, among other options.
We’ve been using milk for non-animal products for longer than we’ve spelt milk with an i, and for longer than we’ve had companies, let alone multi-billion-dollar ones.
I'm not talking about grinding up nuts or grains and calling it milk, I'm talking about engineering yeasts to literally produce the proteins that milk has to create a product that isn't just milk-like, but is literally identical proteins.
You wouldn't call whey protein powder mixed in water milk.
You wouldn't call butter mixed with water milk.
You wouldn't call casein powder mixed with water milk.
Really, we should be calling the OG milk “cow milk” and let the good times roll.
Big milk have been pushing questionable health research and narratives for cow milk for quite some time.
All this coming from someone (me) who drinks 0,5L of cow milk every day.
Yes, yeast milk is milk too. Just like coconut milk.
Maybe but probably not zero, from parents article: "The use of such treated fertilizers will be most relevant for reducing the carbon footprint of milk in countries such as the United Kingdom, Ireland, and the Netherlands, where N fertilizer is a major contributor to the footprint."
In case you are unaware much of the nitrogen in plant matter (food for yeast or cows) comes from fertilizer. And that is extracted using the Haber process (see: https://en.wikipedia.org/wiki/Haber_process ). This runs on natural gas, because it's effectively a waste product of other hydrocarbons being extracted.
Does seem like a lot of carbon for a kg of plastic, though, how does that compare to normal plastic’s carbon footprint?
Why do you mix your units like that.
I'll edit a bit for clarity for you all who live in more consistent places.
If this is counting the methane emissions of the cow itself, that’s not a fair or complete accounting. The cow produces methane in her digestive system after eating grass, and the grass grows by, among other things, extracting CO2 from the air. Then the cow burps methane, the methane combines with atmospheric oxygen and breaks down to CO2 and water, and you have a closed loop; the cow cannot belch more carbon than she eats, and that carbon came from the air in the first place.