Clostridium phytofermentans bacteria. Coloured scanning electron micrograph (SEM) of Clostridium phytofermentans bacteria A gram-positive, anaerobic, rod shaped prokaryote (bacterium). C. phytofermentans is a spore-forming bacterium that naturally occurs amongst decomposing plant and animal matter. Strains of this species appear able to produce ethanol, acetate, carbon dioxide, and hydrogen gas by fermentation of cellulose so may have potential in the production of biofuels. Magnification: x10000 when printed 10 centimetres wide.