We developed a new procedure for stereospecific conversion of various alpha-keto acids to the corresponding D-amino acids with four thermostable enzymes : D-amino acid aminotransferase, alanine racemase, L-alanine dehydrogenase and formate dehydrogenase. Optically pure D-enantiomers of glutamate, phenylalanine and tyrosine were obtained with high conversion rates.