Even if you believe in patents in principle, I have a hard time seeing how this should be patentable. You're basically talking about a protein / enzyme that exists in nature already, not something new that somebody created. Personally I would stringently object to issuing patents for that sort of thing, IF i weren't already opposed to the whole idea of patents in general.
Like another commenter said... patents like this are just about supporting rent-seeking behavior, not advancing scientific progress.
Note that the protein is not patentable, but using it in a process is what's under the patent discussion.
As mentioned elsewhere in the thread, this process is also available for free for academic use, but costs money if a company makes a product that's sold for money.
Penicillin was not patentable, but a process for making and harvesting it easily was. Whether that's a good thing or not is certainly up for debate, although some interesting facts and opinions are documented in this article about penicillin: https://www.awesomestories.com/asset/view/Alexander-Fleming-...
Like another commenter said... patents like this are just about supporting rent-seeking behavior, not advancing scientific progress.