Biotechnological production of unnatural L-amino acids from D,L-5-monosubstituted hydantoins. II: L-α- and L-β-naphthylalanine

Resting cells of Arthrobacter sp. (DSM 3745) with the ability to form L-tryptophan from D,L-5-(3-indolymethyl)hydantoin were used for the bioconversion of D,L-5- alpha - and D,L-5- beta -naphthylmethyl-hydantoin (D,L-5- alpha - and D,L-5- beta -NMH) to the corresponding L-amino acids. Under the optimal reaction conditions of pH 9.7 and 40 degree C specific productivities of 0.2 ( alpha -naphthylalanine) and 0.6 ( beta -naphthylalanine) mM amino acid x g cell dry mass super(-1) x h super(-1) were obtained in a 0.1 M Na sub(2)CO sub(3)/NaHCO sub(3)-buffer in a stirred bioreactor.