This is very inefficient process. Nitrobacter can have 18 hour generation time. Found with Thiobacillus thiooxidans , bacterium that produces sulfuric acid. Ferrobacillus lives off the pH gradient created by acidic pH. This maintains very high proton gradient. Iron functions as electron supplier to get rid of protons.
Cells process an enormous amount of iron for very small yields of energy.
Use CO 2 and Calvin-Benson cycle to make all organic molecules. Several different varieties. Light not needed for this. Need lots of energy to drive this reaction, so need an extra step. Light is needed for this.