Engineering analysis of continuous production of <scp>L</scp>‐aspartic acid by immobilized <i>Escherichia coli</i> cells in fixed beds

Abstract

Abstract The reaction mechanism and decay behavior of aspartase activity for immobilized Escherichia coli cells were investigated by using a sectional packed column. Reaction within the immobilized cell column proceeded at zero‐order on substrate solutions ranging in concentration from 0.1 to 1.0 M , and the initial reaction rate was found to be 1.556 × 10 −2 mol/min/liter of immobilized cells. The effect of temperature on the reaction rate constant was investigated. The Arrhenius plot was straight line at temperatures below 43°C, and the activation energy for immobilized cells was calculated to be 12.36 kcal/mol. Asparatase activity in the immobilized cell column decayed exponentially and uniformly in all sections of a column. Its half‐life was approximately 120 days. The rate of formation of L ‐aspartic acid was shown to be independent of column dimensions.