Editing Rennet (section)

=== 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 [[yeast]]s to make them produce [[recombinant protein|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.<ref name="Law 2010 100–101">{{cite book|last=Law|first=Barry A.|title=Technology of Cheesemaking|year=2010|publisher=WILEY-BLACKWELL|location=UK|isbn=978-1-4051-8298-0|pages=100–101|url=http://eu.wiley.com/WileyCDA/WileyTitle/productCd-1405182989.html}}</ref>

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]].<ref>{{cite news|title=FDA Approves 1st Genetically Engineered Product for Food|url=https://www.latimes.com/archives/la-xpm-1990-03-24-mn-681-story.html|access-date=1 May 2014|newspaper=[[Los Angeles Times]]|date=24 March 1990}}</ref><ref name=chymosinCase>Staff, National Centre for Biotechnology Education, 2006. [https://archive.today/20121223101343/http://www.ncbe.reading.ac.uk/NCBE/GMFOOD/chymosin.html Case Study: Chymosin]</ref>  In 1999, about 60% of US [[hard cheese]]s were made with FPC,<ref name="USDA">{{cite web |url=https://fpc.state.gov/6176.htm|title=Food Biotechnology in the United States: Science, Regulation, and Issues|publisher=U.S. Department of State|access-date=2006-08-14}}</ref> and it has up to 80% of the global market share for rennet.<ref>E. Johnson, J. A. Lucey (2006) [https://www.ncbi.nlm.nih.gov/pubmed/16537950 Major Technological Advances and Trends in Cheese]  J. Dairy Sci. 89(4): 1174–1178</ref> By 2017, FPC takes up 90% of the global market share for rennet.<ref name="johnson2017">{{cite journal | last=Johnson | first=M.E. | title=A 100-Year Review: Cheese production and quality | journal=Journal of Dairy Science | volume=100 | issue=12 | year=2017 | issn=0022-0302 | doi=10.3168/jds.2017-12979 | pages=9952–9965|pmid=29153182|url=https://www.journalofdairyscience.org/article/S0022-0302(17)31054-8/fulltext| doi-access=free }}</ref>

The most widely used FPC is produced either by the fungus ''[[Aspergillus niger]]'' and commercialized under the trademark CHY-MAX<ref>{{cite web|url=http://www.chr-hansen.com/products/product-areas/enzymes/our-product-offering.html|title=Enzymes for Cheese|work=Chr-Hansen.com|archive-url=https://web.archive.org/web/20111101092309/http://www.chr-hansen.com/products/product-areas/enzymes/our-product-offering.html|archive-date=2011-11-01|access-date=2012-07-30}}</ref> by the Danish company [[Chr. Hansen]], or produced by ''[[Kluyveromyces lactis]]'' and commercialized under the trademark Maxiren by the Dutch company DSM.<ref>{{cite web |url=http://www.dsm.com/le/en_US/foodspecialties/html/Products_Maxiren.htm |title=DSM Food Specialties — Product Page — Maxiren |website=DSM.com |access-date=2013-01-28 |url-status=dead |archive-url=https://web.archive.org/web/20120106010450/http://www.dsm.com/le/en_US/foodspecialties/html/Products_Maxiren.htm |archive-date=2012-01-06 }}</ref>

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.<ref name="Law 2010 100–101"/>

Cheeses produced with FPC can be certified kosher<ref>{{cite web|url=http://www.kashrut.com/articles/cheese/|title=Say Cheese!}}</ref><ref name=Chymax>{{cite web|url=https://www.thecheesemaker.com/pdf/Chymosin_Rennet_Specs.pdf|title=Chymax spec sheet}}</ref> and halal,<ref name=Chymax /> and are suitable for vegetarians if no animal-based alimentation was used during the chymosin production in the fermenter.{{Citation needed|date=January 2021}}