Yeasts as Living Objects: Yeast Nutrition

Abstract

Yeasts, like other living organisms, require sources of carbon, nitrogen, phosphorus, trace elements, and growth factors (Phaff et al. 1979). Yeasts cannot grow anaerobically, and so require oxygen. All wild-type yeasts utilize glucose, man-nose, and fructose. Different species may also utilize numerous other sugars and organic acids. Some yeasts can utilize nitrates, others only ammonium salts. They can utilize a wide range of organic nitrogen compounds, including both L- and D-amino acids (LaRue and Spencer 1966). All yeasts require trace elements. Some species can synthesize the growth factors they require, and many cannot, and these must be supplied. Cyniclomyces guttulatus probably requires the most amino acids and vitamins, and an atmosphere high in Co₂, (10–15%); its normal habitat is the cecum of the rabbit, and it is not easy to cultivate in the laboratory.