Stabilization of D-amino-acid oxidase from Trigonopsis variabilis by manganese dioxide

Stabilization of immobilized D-amino-acid oxidase was achieved as follows. Yeast Trigonopsis variabilis producing D-amino-acid oxidase was used to dea minate cephalosporin C to glutaryl-7-aminocephalosporanic acid. Permeabiliz ed cells were co-immobilized with manganese dioxide by entrapment in (poly) acrylamide gel so that hydrogen peroxide, liberated in the reaction, could be partially deactivated and both the enzyme and the substrate could be sta bilized. Activity of entrapped cells was determined by HPLC and enzyme flew microcalorimetry. The process was evaluated in terms of activity, immobili zation yield, storage stability and oxo-product Formation by immobilized pr eparations. The storage stability of immobilized bicatalysts with MnO2 was nearly doubled and production of 2-oxoadipyl-7-aminocephalosporanic acid wa s 2-3-fold higher than by entrapped cells without MnO2. Glutaryl-7-aminocep halosporanic acid can be easily obtained from the resulting ore-product by a non-enzymic reaction via externally added hydrogen peroxide.