Microbial rennet
A coagulant made by moulds or other microbes rather than taken from animals, used for vegetarian cheese.
Also: fungal rennet, vegetarian rennet, microbial coagulant
Microbial rennet is an enzyme that sets milk like calf rennet but is produced by growing moulds, most often Rhizomucor miehei, in fermentation tanks. It is widely used in India, the Middle East and elsewhere, and is the reason so many cheeses sold in India carry the green vegetarian mark. It is cheaper than animal rennet and acceptable to vegetarians and many religious authorities. Its enzymes cut protein a little less precisely than chymosin, so in long-aged cheeses it can sometimes produce bitterness, which is why makers of very old cheeses prefer calf rennet or fermentation-produced chymosin. Strictly, chymosin made by fermentation is a separate product, though both are often sold as vegetarian rennet.