I suggest going back and giving the article a second read (or, doing additional research). While the headline may seems to be implying meat substitutes (such as soy, seaweed, etc), that's just a misdirection or misunderstanding.
The entire project is about growing cellular meat no different than what can be procured today. However, the essential difference is removing the 95% overhead factor. That is, when we consider a biological entity, such as cattle or poultry, there is a tremendous amount of 'waste' necessary to drive the engine aka body.
If we can remove all that, and just focus on muscle (meat), then animal husbandry would begin to resemble hydroponic, hot house tomatoes. Imagine identifying and isolating the core genetic compounds and merely supplying them with essential nutrients to organically "grow" meat?
That's is where tech is headed; think of the future as "meat robots".
Cellular agriculture - culturing meat cells in vats, instead of in bigger, dirtier, and less efficient factory farms.
This approaches the theoretical limit of feed efficiency, by cutting out all the bones, nerves, skin and stuff, before they consume any nutrients from feed - you just feed what you are going to eat (or sell).
Faster, cheaper, better (in some ways) - and much safer. Animal slaughter, meatpacking and fisheries have the highest rate of injury to workers of all industries. Animal diseases and food-borne illness/contamination safety could also be dramatically better controlled in a closed culture tank process than in a feedlot.
You are correct - I read the excerpt and assumed it was plant-based proteins.
But reading the article raised even more questions. The comment from the consultant seemed to hit it right on - people want simple and clean food, yet now these food scientists want to sell bioengineered food grown in a lab, with many dozens of ingredients. That’s quite a disconnect.
I also sense quite a bit of ideological blindness and arrogance from its inventors. Sure, they have money to burn, but trying to change people’s tastes due to one’s concern over “global warming” is a fool’s errand. They may find it easier to instead engineer humans’ and their tastes to enjoy eating plant protiens instead.
I always see things in terms of money - and in my view, such a project is one of many fantasy projects, founded in the vast sums of money which have pooled in silicon valley over the years, due to massive debt, blowing huge asset bubbles in tech, in manipulated interest rates and our fiat currency.