Immobilization by Polyurethane of Pseudomonas dacunhae Cells Containing l -Aspartate β-Decarboxylase Activity and Application to l -Alanine Production

Abstract

Whole cells of Pseudomonas dacunhae containing L-aspartate 0-decarboxylase activity were immobilized by mixing a cell suspension with a liquid isocyanate-capped polyurethane prepolymer (Hypol; W. R. Grace & Co., Lexington, Mass.). The immobilized cell preparation was used to convert L-aspartic acid to L-alanine. Properties of the immobilized P. dacunhae cells containing aspartate 0-decarboxylase activity were investigated with batch reactors. Retention of enzyme activity was observed to be as much as 100% when cell lysis was allowed to occur before immobilization. The pH and temperature optima were determined to be 5.5 and 45°C, respectively. Immobilized P. dacunhae L-aspartate ,-decarboxylase activity was stabilized by the addition of 0.1 mM pyridoxal-5-phosphate and 0.1 mM a-ketoglutaric acid to a 1.7 M ammonium aspartate (pH 5.5) substrate solution. Under conditions of semicontinuous use in a batch reactor, a 2.5% loss in immobilized Laspartate ,(-decarboxylase activity was observed over a 31-day period.

Improving the activity and synergistic catalysis of l-aspartate β-decarboxylase by arginine introduction on the surface

“…The biosynthesis of L-alanine uses L-aspartic acid as the substrate and L-aspartate β-decarboxylase (ASD) as the key enzyme. [1][2][3] ASD belongs to the PLP (5′-pyridoxal phosphate)-dependent decarboxylase family and catalyzes the decarboxylation of L-aspartic acid into L-alanine. It invariably exhibits activity in an acidic environment.…”

Characterization and rational modification of aspartate 4‐decarboxylase from Acinetobacter radioresistens for the production of l‐alanine

“…The culture medium of Pseudomonas dacunhae was used as the catalyst to convert 40 g of solid L-aspartic acid to L-alanine (Chibata et al, 1965). In 1984, P. dacunhae cells were immobilized by carrageenan for the production of L-alanine (Fusee & Weber, 1984). Senuma et al (1989) optimized the immobilized reactor and adopted a high-pressure column reactor to improve production efficiency and realized the industrial production of D-aspartic acid.…”