coagulants result in bitterness and low yield in cheese, especially when aged for a long time. Over the years, microbial coagulants have improved a lot, largely due to the characterization and purification of secondary enzymes responsible for bitter peptide formation/non-specific proteolytic breakdown in cheese aged for long periods. Consequently, it has become possible to produce several high-quality cheeses with microbial rennet. It is also suitable for the elaboration of vegan cheese, provided no animal-based ingredients are used in its production. Fermentation-produced chymosin Because of the above imperfections of microbial and animal rennets, many producers sought other replacements of rennet. With genetic engineering it became possible to isolate rennet genes from animals and introduce them into certain bacteria, fungi, or yeasts to make them produce recombinant chymosin during fermentation. The genetically modified microorganism is killed after fermentation and chymosin isolated from the fermentation broth, so that the fermentation-produced chymosin (FPC) used by cheese producers does not contain a GMO or any GMO DNA. FPC is identical to chymosin made by an animal, but is produced in a more efficient way. FPC products have been on the market since 1990 and, because the quantity needed per unit of milk can be standardized, are commercially viable alternatives to crude animal or plant rennets, as well as generally preferred to them in industrial production. Originally created by biotechnology company Pfizer, FPC was the first artificially-produced enzyme to be registered and allowed by the US Food and Drug Administration. In 1999, about 60% of US hard cheeses were made with FPC, and it has up to 80% of the global market share for rennet. By 2017, FPC takes up 90% of the global market share for rennet. The most widely used FPC is produced either by the fungus Aspergillus niger and commercialized under the trademark CHY-MAX by the Danish company Chr. Hansen, or produced by Kluyveromyces lactis and commercialized under the trademark Maxiren by the Dutch company DSM. FPC is chymosin B, so it is purer than animal rennet, which contains a multitude of proteins. FPC provides several benefits to the cheese producer compared with animal or microbial rennet: higher production yield, better curd texture, and reduced bitterness. Cheeses produced with FPC can be certified kosher and halal, and are suitable for vegetarians if no animal-based alimentation was used during the chymosin production in the fermenter. Nonrennet coagulation Many soft cheeses are produced without use