A plant peptide amidase from the flavedo of oranges is known; this can be obtained only in small quantities and is seasonal. The proposed new enzymes are microbial peptide amidases which can be obtained from micro-organisms recovered from soil samples in a “double screening” and grown. These microbial peptide amidases are particularly useful for (a) the production of peptides and N-terminal-protected amino acids, (b) racemate splitting of N-protected amino acid amides, (c) obtaining non-proteinogenous D-amino acids, and (d) obtaining new N&agr;-protected D-amino acid amides.