Immobilization of hydantoin cleaving enzymes from Arthrobacter aurescens DSM 3747 — Effect of the coupling method on the stability of the L-N-carbamoylase

Abstract

Different coupling methods were tested for the immobilization of the N-carbamoyl-L-aminoacid amidohydrolase (L-N-carbamoylase) partially purified from Arthrobacter aurescens DSM 3747. The operational stability of the immobilized biocatalyst was measured using both consecutive batch reactions and continuously operated fixed bed reactors, while the stability of the free L-N-carbamoylase was investigated using an enzyme membrane reactor. The long term stability of the enzyme was markedly enhanced by all immobilization methods and carriers tested. In consecutive batch reactions the operational stability remained relatively low and significant differences in biocatalysts stability were not observed between the different immobilization methods used. In contrast there were significant differences in the stability when the biotransformations were carried out using fixed bed reactors. As a result of this comparison the determination of the operational stability of the air-sensitive L-N-carbamoylase on a batch-to-batch basis seems not to be useful.