Cross-linked cell aggregates of Trigonopsis variabilis:: D-amino acid oxidase catalyst for oxidation of cephalosporin C

Trigonopsis variabilis CBS 4095 was treated with alkali (pH 11, 30 min), heated (65degreesC, 60 s) and immobilized. Glutaraldehyde, polyethyleneimine and a cross-linking reagent formed by reaction of polyethyleneimine with glutaraldehyde were used for stabilization of D-amino acid oxidase in the cells, as well as for aggregation and binding of the cells. A specific activity of 82-98 U of D-amino acid oxidase per g dry mass was produced with a yield of about 20%. The half-life time of 142 repeated conversion cycles corresponds to a productivity of 130 kg cephalosporin C oxidized per kg catalyst dry mass.