Methods and systems to achieve clean fuel processing systems in which carbon dioxide emissions (1) from sources (2) may be processed in at least one processing reactor (4) containing a plurality of chemoautotrophic bacteria (5) which can convert the carbon dioxide emissions into biomass (6) which may then be used for various products (21) such as biofuels, fertilizer, feedstock, or the like. Sulfate reducing bacteria (13) may be used to supply sulfur containing compounds to the chemoautotrophic bacteria (5).