All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
If these enzymes are extracted from animals that were slaughtered in accordance with the Sharee‘ah, then there is absolutely nothing wrong with eating the food products that contain such enzymes. But if such enzymes are extracted from dead animals, it is obligatory to avoid them because it is impermissible to eat dead animals or any product whose ingredients include dead animal extracts.
As for animal rennet, the scholars held different opinions regarding the ruling on eating the food made from rennet extracted from an animal that was not slaughtered in accordance with the Sharee‘ah. The opinion which Shaykhul-Islam Ibn Taymiyyah chose is that animal rennet is ritually pure and it is permissible in an absolute sense to eat cheese that is made from animal rennet. He said: “It was said that there is consensus of opinion among the Companions in this regard. If they make cheese – and cheese is made with rennet – there are two opinions in this regard, the most preponderant of which is that such cheese is lawful for consumption and the milk and animal rennet of dead animals are ritually pure, because when the Companions conquered the lands of Iraq, they ate from the cheese made by the Majoos (Magi); and this was something acceptable and common among them. What was reported that some of them disliked it requires scrutiny, as it was reported on the authority of some scholars of Hijaaz (Makkah and Madeenah), which calls for scrutiny. The people of Iraq were more knowledgeable of this matter since the Majoos lived in their lands, not in the lands of Hijaaz. This is proved by the authentic report that Salmaan Al-Faarisi, who was the deputy of ‘Umar ibn Al-Khattaab over Madaa’in (capital of Persia at the time) and used to call the Persians to Islam, was asked about animal fat, cheese, and fur. He replied, ‘The lawful is what Allah has made lawful in His Book, and the unlawful is what Allah has made unlawful in His Book. Whatever He has made no mention of is pardoned.’ [Abu Daawood narrated this Hadeeth as Marfoo’, i.e. attributed to the Prophet, sallallaahu ‘alayhi wa sallam]
It is known that the question was not about the cheese made by Muslims or by the People of the Book (Jews and Christians), which was a clear matter. Rather, the question was about the cheese made by the Majoos; so this proves that Salmaan used to issue his Fatwa that it was lawful for consumption.” [End of quote]
Allah Knows best.