Simplify the following text for a Grade 9 native English-speaking person.
Original: Vegetarian alternatives to rennet are available ; most are produced by fermentation of the fungus Mucor miehei , but others have been extracted from various species of the Cynara thistle family .
Simplified: Most of these are produced by fermentation of the fungus called Mucor miehei . However , others have been extracted from various species of the Cynara thistle family .