OCHROBACTRUM-ANTHROPI NCIMB-40321 - A NEW BIOCATALYST WITH BROAD-SPECTRUM L-SPECIFIC AMIDASE ACTIVITY

Of 125 microorganisms that were able to use alpha-hydroxy acid amides as sole nitrogen source, Ochrobactrum anthropi NCIMB 40321 was selected for its ability to hydrolyse racemic amides L-selectively. The substrate specificity of whole O. anthropi cells is remarkably wide and ranges from alpha-H-alpha-amino-, alpha-alkyl-alpha-amino, N-hydroxy-alpha-amino acid amides to alpha-hydroxy-acid amides. After 50% conversion, both the L-acids formed and the remaining D-amides were present in >99% enantiomeric excess, and ammonia accumulated in stoichiometric amounts. Using mandelic acid amide as a model substrate, the hydrolysis was optimized. Optimal rates were observed at pH 8.5 at 50-degrees-C. At higher temperatures the initial rate was even higher; however, fairly rapid inactivation occurred.