Distribution, industrial applications, and enzymatic synthesis of D-amino acids

d-Amino acids exist widely in microbes, plants, animals, and food and can be applied in pharmaceutical, food, and cosmetics. Because of their widespread applications in industry, d-amino acids have recently received more and more attention. Enzymes including d-hydantoinase, N-acyl-d-amino acid amidohydrolase, d-amino acid amidase, d-aminopeptidase, d-peptidase, l-amino acid oxidase, d-amino acid aminotransferase, and d-amino acid dehydrogenase can be used for d-amino acids synthesis by kinetic resolution or asymmetric amination. In this review, the distribution, industrial applications, and enzymatic synthesis methods are summarized. And, among all the current enzymatic methods, d-amino acid dehydrogenase method not only produces d-amino acid by a one-step reaction but also takes environment and atom economics into consideration; therefore, it is deserved to be paid more attention.