Photofermentation

Photofermentation is the fermentative conversion of an organic substrate into biohydrogen, carried out by a diverse group of photosynthetic bacteria through a series of biochemical reactions involving three steps similar to anaerobic conversion. Photofermentation differs from dark fermentation because it only proceeds in the presence of light. For example, photofermentation using the purple non-sulfur bacterium Rhodobacter sphaeroides, or many other purple non-sulfur bacteria, can convert small molecular fatty acids into hydrogen and other products.