Growth of a photosynthetic bacterium anaerobically in darkness, supported by "oxidant-dependent" sugar fermentation.

Rhodopseudomonas capsulata can obtain energy for growth from light (anaerobically) and can also grow heterotrophically in darkness using alternative energy conversion modes, namely, aerobic respiration or an unusual type of anaerobic catabolism of sugars. Dark anaerobic growth with fructose as sole carbon and energy source is dependent on the presence of an "accessory" oxidant such as trimethylamine-N-oxide, is accompanied by production of lactate and other classical fermentation products, and yields cells with a high content of photosynthetic pigments and polyhydroxybutyrate.