Stabilization and immobilization of Trypanosoma bruceiornithine decarboxylase for the biobased production of 1,4-diaminobutane

Abstract

Using the biorefinery concept, L-arginine could become widely available from biomass waste streams via the nitrogen storage polypeptide cyanophycin. In our pursuit to develop a route from biobased L-arginine to 1,4-diaminobutane, one of the monomers in nylon-4,6, we were previously successful in the stabilization and immobilization of Bacillus subtilisarginase. In the present study, we investigated the stabilization and immobilization of Trypanosoma bruceiornithine decarboxylase (EC 4.1.1.17) (TbODC) for its application in the decarboxylation of L-ornithine, the final step in the envisioned route towards 1,4-diaminobutane. The stability observed for TbODCin vitro was substantially improved upon addition of dithiothreitol (DTT), which not only has a stabilizing, but also an activating effect. For optimal TbODC performance, the pH should be controlled at pH 8 and the ionic strength should be kept to a minimum. The temperature for optimal productivity is 40 °C. Immobilization of TbODC on Sepabeads EC-HFA was most successful, leading to an almost three-fold improvement in operational stability as compared to the soluble enzyme. Overall, we demonstrated that by optimization of reaction conditions and covalent immobilization the productivity of TbODC was vastly improved, opening up possibilities for its application in the biobased production of 1,4-diaminobutane.