Na⁺‐driven ATP synthesis in <i>Methanobacterium thermoautotrophicum</i> can be modulated with sodium ion concentrations in the growth medium

Abstract

Methane formation by nongrowing cells of Methanobacterium thermoautotrophicum ΔH can be enhanced with sodium ions only when the cells were originally grown in the presence of a low (5 mM) concentration of NaCl. ATP synthesis in the cells driven by an artificially imposed Na + gradient can be modulated by changing the sodium ion concentration in the growth medium while H + gradient‐driven ATP synthesis does not depend on it. Stimulation of the entire ATPase activity with Na + in permeabilized cells depends also on the Na + concentration in the growth medium. The results obtained might indicate the presence of an inducible Na + ‐translocating ATPase in Methanobacterium thermoautotrophicum .