Yeast Extract is a concentrate of the water- soluble portion of Saccharomyces cerevisiae cells that have been autolyzed. . It is rich in vitamins, especially B-complexes, amino acids and other growth factors. It is used in many microbiological culture media formulations as an excellent growth source.Yeast extract is considered a non-animal product and is used extensively for many non-animal formulations of bacterial, fungal, mammalian and insect cell culture.