Properties of microbial photosynthetic systems Property Cyanobacteria Green and purple Purple nonsulfur bacteria bacteria Photo-pigment Chlorophyll Bcteriochlorophyll Bcteriochlorophyll O2 production Yes No No Electron donors H2O H2,H2S,S H2,H2S,S Carbon source C02 C02 Organic /CO2 Primary products of ATP NADPH ATP ATP energy conversionProperty Cyanobacteria Green and purple bacteria Purple nonsulfur bacteria Photo - pigment Chlorophyll Bcteriochlorophyll Bcteriochlorophyll O2 production Yes No No Electron donors H2O H2, H2S, S H2, H2S, S Carbon source CO2 CO2 Organic / CO2 Primary products of energy conversion ATP + NADPH ATP ATP Properties of microbial photosynthetic systems