Penicillin G → Penicillin G Potassium

Participants

Reaction Conditions

Reaction Steps

Culture treated as under A is incubated for about 72 seconds at 30° C. in the shaking machine until it attains a cell titre of >109 per ml of culture solution. 0.1 ml of this cell suspension is transferred into 10 ml of the following nutrient solution (nutrient solution B): 0.05% NaH2PO4, 0.20% K2HPO4, 0.05% MgSO4.7H2O, 0.02% CaCl2.2H2O, 0.005% MnSO4.4H2O, 0.005% (Fe)2SO4.7H2O, 0.10% (NH4)SO4, 0.0001% biotine, 0.10% Tween 80 and 0.10% BNC. After shaking for 18 hours at 30° C. diluted with fresh, preheated nutrient solution of the same composition to about 106 cells per ml, 1000 IU penicillin G are added and incubation for a further 7 hours is carried out. The antibioticum is then removed by centrifuging of the cells with washing with sterile, physiologic sodium chloride solution and the cells further incubated for 3 days in the above-mentioned medium with 0.2% sitosterol instead of BNC. The penicillin treatment is repeated once more and the cell suspension finally plated out on the same nutrient medium A plus 1.6% agar. After the propagation of the cells to visible colonies, the cells are transfered with the aid of the "replica stamp technique" on nutrient medium B plus 1.6% agar and those colonies are selected and used as strain cultures which are not able to continue to grow, or scarecly able, on this medium.

Provenance & Evidence