Solar Thermal Energy Cycle Based on Sulfur and Sulfide Oxidizing Bacteria

New solar energy technologies for the production of biomass for the purpose of synthesizing methane, hydrogen and proteins could be based on the solar generation of the inorganic energy source (Fe2+, metal sulfides) of chemoautotrophic bacteria (Thiobacilli). The resulting energy cycle is identical with the life sustaining processes coupled to black smokers in the deep sea with the difference that solar energy replaces geothermal energy. Progress and difficulties are discussed for energy and fuel generation on the basis of a solar driven sulfur cycle involving sulfate reduction using solar energy and sulfide oxidation by Thiobacillus ferrooxidans. The rate determining steps for catalysis of sulfate reduction and interfacial oxidation of sulfides are discussed. The potential advantages of this energy cycle for space exploration, terrestrial carbon dioxide fixation and technologies for energy and material production are outlined.