Squalene was traditionally sourced from the livers of sharks, with approximately 3000 required to produce one ton of squalane.[4] Due to environmental concerns, olive oil, rice and sugarcane as non-animal sources have been commercialized, supplying about 40% of the industry total in 2014.[4] In manufacturing, farnesene is produced from fermentation of sugarcane sugars using genetically modified Saccharomyces cerevisiae yeast strains.[4] Farnesene is then dimerized to isosqualene and then hydrogenated to squalane.[4][5]