Many Jews who only eat kosher meat still eat cheese not marked as
kosher. The prohibition on non-kosher cheese is to a certain extent
based on the use of animal enzymes to make the cheese. I am interested
to know, in this context, how most cheese in the United States is
actually prepared.

-That is, what percentage of cheese in the US is made exclusively using
enzymes that are bioengineered vs. those that include animal derived
enzymes?

-Are cheeses in restaurants more/less likely to have animal enzymes?

-Are specific types/ darker cheeses more likely to have animal enzymes?

-Are there any US regulations that would prevent/hamper use of animal
enzymes in cheese preparation?

-And, less importantly, Is there really any difference between cheese
in the US and say South America or Europe?

Thank you for your answers.

This article may be of interest to you:

http://www.natural-connection.com/resource/tnc_reference_library/cheese.html