H.Phototrophic,Chemolithotrophic,and Methanotrophic Proteobacteria 17.2 Purple Phototrophic Bacteria 17.3 The Nitrifying Bacteria 17.4 Sulfur-and Iron-Oxidizing Bacteria 17.5 Hydrogen-Oxidizing Bacteria 17.6 Methanotrophs and Methylotrophs CHEN FENG,MICROBIOLOGY,SJTUChen Feng, Microbiology, SJTU II. Phototrophic, Chemolithotrophic, and Methanotrophic Proteobacteria • 17.2 Purple Phototrophic Bacteria • 17.3 The Nitrifying Bacteria • 17.4 Sulfur- and Iron-Oxidizing Bacteria • 17.5 Hydrogen-Oxidizing Bacteria • 17.6 Methanotrophs and Methylotrophs