Nitrobacter's genus of mostly rod-shaped, gram-negative, and chemoautotrophic bacteria. Nitrobacter plays an important role in nitrogen cycle by oxidizing nitrite into nitrate in soil. Unlike plants, where electron transfer in photosynthesis provides the energy for carbon fixation, Nitrobacter use energy from the oxidation of nitrite ions, NO2-, into nitrate ions, NO3- to fulfill their carbon requirements. Nitrobacter have an optimum pH between 7.3 and 7.5, and will die in temperatures exceedin… (More on Nitrobacter)