The ruling on extracting proteins from the skins of carrion and pigs

The questioner:
Honorable Shaykh, may Allah preserve you. Currently, in some modern industrial countries, proteins are being extracted, along with other nutritional elements, from human solid waste to be added back to food, whether by creation.

The Shaykh:
Repeat the question.

The questioner:
Currently, in some modern industrial countries, proteins are being extracted, along with other elements.

The Shaykh:
From what are the proteins extracted? From what? Hmm? The skins of what?

The questioner:
Yes.

The Shaykh:
The skins of carrion and the skins of pigs.

The questioner:
If Allah wills.

The Shaykh:
This is not permissible. These are forbidden; nothing may be taken from them. All their parts are ritually impure. Yes. Hmm?

The questioner:
I hear. I am speaking about the skins of sheep and cows and their bones.

The Shaykh:
If they are slaughtered according to the law, all their parts are lawful. If slaughtered according to the law, all of it is lawful, its meat and all its parts. As for what is not slaughtered according to the law, it is forbidden. Yes.