N-carbamoyl-D-p-hydroxyphenylglycine production using immobilized D-hydantoinase from recombinant E-coli

An immobilized D-hydantoinase was characterized and employed to produce N-carbamoyl-D-p-hydroxyphenylglycine (CpHPG) in a repeated batch process. The V-max and K-m of the immobilized D-hydantoinase at 50 degrees C were 6.28 mM min(-1) g(-1) biocatalyst and 71.6 mM, respectively. The product CpHPG did not inhibit the activity of D-hydantoinase. Optimal reaction temperature was 60 degrees C. A decrease in activity of immobilized D-hydantoinase due to thermal inactivation could be described as first-order decay; the deactivation energy was 23.97 Kcal mol(-1). Under process conditions (50 degrees C, 10% w/v substrate, and pH 8.5), the half-life of the immobilized D-hydantoinase was eight batches. The attrition of immobilized D-hydantoinase particles with a large amount of insoluble substrate particles during stirring resulted in fine biocatalyst particles. In addition to the thermal inactivation, the loss of fine biocatalyst particles during the recovery step contributed to the low operational stability. (C) 1996 by Elsevier Science Inc.