 The energy obtained from inorganic oxidation varies depending on the substrate and the reaction.For example, the oxidation of hydrogen sulfide to elemental sulfur produces far less energy (50.1 kcal/mol or 210.4 kJ/mol) than the oxidation of elemental sulfur to sulfate (149.8 kcal/mol or 629.2 kJ/mol).The majority of lithotrophs fix carbon dioxide through the Calvin cycle, an energetically expensive process.