>700 (belonging to 100 genera) species
||Fonseca G. G., Gombert A. K., Heinzle E., Wittmann C. Physiology of the yeast Kluyveromyces marxianus during batch and chemostat cultures with glucose as the sole carbon source. FEMS Yeast Research, 7: 422–435, 2007 p.422 left columnPubMed ID17233766
||Kurtzman CPFell JW (1998) The Yeasts, A Taxonomic Study. Elsevier, Amsterdam.
||p.422 left column:"The number of described yeast species increases every year and in the last compendium edited by Kurtzman & Fell (primary source), more than 700 different species belonging to 100 genera are reported. In spite of this immense spectrum, industrial or biotechnological applications are still limited to a very small number of species, mainly belonging to the genera Saccharomyces, Kluyveromyces, Hansenula, Pichia and Yarrowia (de Winde, 2003). Among these, Saccharomyces cerevisiae occupies an outstanding position, as it is not only the most widely employed yeast but also the most utilized microorganism in the biotechnological industry."