Lactobacillus is a genus of gram-positive anaerobic bacteria, named as such because most of its members convert lactose to lactic acid. They are common and usually benign inhabitants of the bodies of humans and other animals - for example present in the gastrointestinal tract and the vagina. The production of lactic acid makes their environment acidic which inhibits the growth of some harmful bacteria. Industrially some lactobacillus species are used for the production of yoghurt and cheese. Several members of the genus have had their genome sequenced.