Enzymatic production of L-ornithine from L-arginine with recombinant thermophilic arginase

In this study, to develop a simple and efficient enzymatic production process for the environment-friendly synthesis of L-ornithine from L-arginine, the Escherichia coli BL21 (DE3) strain overexpressing arginase (ARG) from Bacillus ca/dove/ox was chosen as the potential biocatalyst. The biochemical properties of the recombinant ARG were characterized and compared with those of the native enzyme. The maximal conversion rate of L-arginine to L-ornithine was 87.1% with a final L-ornithine concentration of 112.3 g/L under the following optimal conditions: 170 g/L L-arginine, 12 g/L whole-cell biocatalyst, 10 mu M Mn2+, 60 degrees C, pH 9.0, and 4 h of incubation. When compared with a recent work, the biocatalytic process described in the present study achieved higher average L-ornithine synthesis rate of 26.2 g/L/h, and thus has great potential for large-scale production of L-ornithine. (C) 2014 Elsevier B.V. All rights reserved.