Anaerobic fermentation in Cyanidium caldarium.

Cyanidium caldarium cells kept anaerobically in the dark have no detectable gas exchange and form exclusively D-(-)-lactate at the expense of their starch content. The addition of acetate enhances both starch breakdown and lactate accumulation by a factor of two. During prolonged anaerobiosis Cyanidium is able to keep its energy charge at a low, but fairly constant level. The adenylate-kinase equilibrium, however, undergoes considerable changes, indicative of a regulatory mechanism which maintains a high energy charge particularly by accumlating AMP instead of ADP.