Poly (y-glutamic acid), a novel polyanionic and multifunctional macromolecule synthesized by Bacillus species, has attracted considerable attention because of its eco-friendly, biodegradable and biocompatible characteristics. Recently, its application in a wide range of fields such as food, agriculture, medicine, hygiene, cosmetics and the environment has been explored. This book discusses the chemistry, food sources and health benefits of glutamic acid. Topics include the self-organization and stability of poly a-glutamic acid with cationic surfactants; metabolism and physiology of glutamate in chickens; different roles and applications of glutamic acid in the biomedical field; glutamic acid in food and its thermal degradation in acidic medium; application of a natural biopolymer poly (y-glutamic acid) as a bioflocculant and adsorbent for cationic dyes and chemical mutagens; and biodegradability of the y- and a-enantiomeric forms of the poly (glutamic acid) by bacillus licheniformis NCIMB 11709.