Major nutritional type Sources of energy, hydrogen/electrons, and carbon Representative microorganisms Photoautotroph (Photolithotroph) Light energy, inorganic hydrogen/electron(H/e- ) donor, CO2 carbon source Algae, Purple and green bacteria, Cyanobacteria Photoheterotroph (Photoorganotroph) Light energy, inorganic H/e- donor, Organic carbon source Purple nonsulfur bacteria, Green sulfur bacteria Chemoautotroph (Chemolithotroph) Chemical energy source (inorganic), Inorganic H/e￾donor, CO2 carbon source Sulfur-oxdizing bacteria, Hydrogen bacteria, Nitrifying bacteria Chemoheterotroph (Chenoorganotroph) Chemical energy source (organic), Organic H/e￾donor, Organic carbon source Most bacteria, fungi, protozoa Nutritional types of microorganismsMajor nutritional type Sources of energy, hydrogen/electrons, and carbon Representative microorganisms Photoautotroph (Photolithotroph) Light energy, inorganic hydrogen/electron(H/e- ) donor, CO2 carbon source Algae, Purple and green bacteria, Cyanobacteria Photoheterotroph (Photoorganotroph) Light energy, inorganic H/e- donor, Organic carbon source Purple nonsulfur bacteria, Green sulfur bacteria Chemoautotroph (Chemolithotroph) Chemical energy source (inorganic), Inorganic H/e￾donor, CO2 carbon source Sulfur-oxdizing bacteria, Hydrogen bacteria, Nitrifying bacteria Chemoheterotroph (Chenoorganotroph) Chemical energy source (organic), Organic H/e￾donor, Organic carbon source Most bacteria, fungi, protozoa Nutritional types of microorganisms