Process for obtaining microorganisms containing peptide amidase, microorganisms obtained therewith, peptide amidases contained in them and use thereof

A process for the enzymatic cleavage of a C-terminal amino group from a peptide amide or from an N-terminally protected amino acid amide to form a peptide or N-terminally protected amino acid, said process comprising deamidating said peptide amide or N-terminally protected amino acid amide with a microbial peptide amidase, wherein said microbial peptide amidase:

• (a) selectively and hydrolytically splits off the free amino group on the C-terminal end of peptide amides;
• (b) does not split peptide bonds;
• (c) does not deamidate N-substituted amino acid amides;
• (d) has an optimum pH of 6.0±0.5;
• (e) is obtained by the process of cultivating Xanthomonas maltophilia microorganisms containing peptide amidase in nutrient media comprising a source for carbon, nitrogen and mineral salts, said process comprising the steps of:
• (i) incubating said microorganisms in a first nutrient medium containing amide nitrogen as a nitrogen source to produce colonies;
• (ii) inoculating said colonies onto a second nutrient medium containing N-acetyl-D,1-methionine amide;
• and
• (iii) incubating said colonies so that microorganisms which grow in both nutrient media are selected;
• and
• and wherein said peptide amidase has the N-terminal amino acid sequence of SEQ ID NO:1.