saturation carbon dioxide should be kept at non toxic concentrations by increasing the airflow through the fermentor so that the carbon dioxide concentration in the outlet gas is less than 5 more particular less than 2 5 the fermentation can be carried out in a batch a fed batch or a continuous fermentation process mode the process may be carried out by controlling various non growth limiting nutrients in their optimal concentrations dependent on the growth limiting nutrient of choice these growth non limiting nutrients may contain any relevant source of carbon nitrogen phosphor or sulphur or may contain oxygen of course the recovery of the impure clavulanic acid solution as formed by the fermentative process of the present invention as well as the subsequent conversion thereof into a pharmaceutically acceptable salt by methods known in the art do form an aspect of the present invention one of the most advantageous procedures is the conversion of the impure clavulanic acid into an amino salt thereof by adding the corresponding amino salt forming compound as for instance n n n u2032 n u2032 tetramethylethylenediamine 1 3 bis di methylamino 2 propanol t butylamine t octylamine benzhydrylamine and bis 2 dimethylamino ethyl ether and reacting said amine clavulanate with.