Different ionic specificities of ATP synthesis in extremely alkaliphilic sulfate-reducing and acetogenic bacteria

Ionic specificity of oxidative phosphorylation was studied in Natroniella a cetigena and Desulfonatronum lacustre, which are new alkaliphilic anaerobes that were isolated from soda lakes and have a pH growth optimum of 9.5-9.7 . The ability of their cells to synthesize ATP in response to the impositio n of artificial Delta pH(+) and Delta pNa(+) gradients was studied. As dist inct from other marine and freshwater sulfate reducers and extremely alkali philic anaerobes, D. lacustre uses a Na+-translocating ATPase for ATP synth esis. The alkaliphilic acetogen N. acetigena, which develops at a much high er Na+ concentration in the medium, generated primary Delta pH(+) for ATP s ynthesis. Thus, the high Na+ concentrations and alkaline pH values typical of soda lakes do not predetermine the type of bioenergetics of their inhabi tants.