PRODUCTION OF OPTICALLY PURE L-ALANINE BY IMMOBILIZED PSEUDOMONAS SP.BA2 CELLS

The conditions for immobilizing the new L-aminoacylase-producing bacte rial strain, Pseudomonas sp. BA2, by entrapment in kappa-carrageenan g el, were investigated. The optimal gel concentration and cell load wer e determined. The addition of CoCl2 and N-acetyl-L-alanine to the immo bilizing matrix enhanced L-aminoacylase activity. The enzymatic proper ties of immobilized Pseudomonas sp. BA2 were investigated. Enzyme acti vity in immobilized cells was optimal at a pH of 6.5 using 0.15 mol dm (-3) Tris-maleate buffer at 45 degrees C. The presence of 0.7 mmol dm( -3) CoCl2 in the enzymatic reaction mixture improved L-aminoacylase ac tivity. The immobilized cell preparation was used for the production o f L-alanine from N-acetyl-DL-alanine in a batch reactor. Conversions o f 100% were obtained using substrate concentrations ranging from 20 to 200 mmol dm(-3). The reactor production was 0.74 mol h(-1) g cell(-1) dm(-3) which is noticeably higher than that previously reported in th e literature. (C) 1998 Society of Chemical Industry.