Production of intracellular enzyme by Corynebacterium glutamicum T6-13 protoplasts immobilized in Ca-alginate gels

The glutamate dehydrogenase (GDH) (EC 1.4.1.4) productivity of the immobilized Corynebacterium glutamicum T6-13 protoplasts in Ca-alginate gels was investigated. GDH in Corynebacterium glutamicum T6-13 cells is an intracellular enzyme. The cells pretreated with 0.5 U/l-1 penicillin G were used for the preparation of protoplasts. Protoplasts were prepared by treating these cells with lysozyme at 30 degrees C for 14 h in 0.5 M NaCl solution and separating the protoplasts. Protoplasts were directly immobilized in 3% Ca-alginate gels (method I). The immobilized protoplasts could be also prepared by treating the immobilized whole cells with lysozyme (method II); this method was more convenient than method I. The GDH productivity of the immobilized protoplasts amounted to 205% of that of the free cells (intracellular). The immobilized protoplasts could be repeatedly used for at least 6 batches (18 days) and had good storage stability.