Chemosynthesis is the biological conversion of inorganic matter to create nutrients to sustain living organisms. One of the most widely known or popular examples is its use in the Giant Tube Worm, which uses an organ that contains chemosynthetic bacteria.

The chemosynthesis of hydrogen sulfide uses 12 hydrogen sulfides and 6 carbon dioxides to create a carbohydrate, 6 waters, and 12 sulphurs. Is it feasible that a bacteria or plant-like organism alter this process to further process that water into oxygen, and why would it do this?

  • $\begingroup$ To produce oxygen by chemical means, we need a powerful oxidizer (fluoride, chlorine-oxygen compounds, peroxides etc.). Such an oxidizer is normally not available in environment, and is often harmful to the bacteria when it comes in contact with it. $\endgroup$
    – Alexander
    Jul 27, 2018 at 23:58
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    $\begingroup$ Not without an outside powersource no, even green sulfur bacteria need the glow from radioactive rocks. $\endgroup$
    – John
    Jul 28, 2018 at 1:16
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    $\begingroup$ What problem are you trying to solve with chemosynthesis? $\endgroup$
    – RonJohn
    Jul 28, 2018 at 1:31

4 Answers 4


Frame Challenge

I won't answer how to produce oxygen because another answer already does that and because you could use water, carbon dioxide and ATP in order to produce glucose and oxygen using the reverse Krebs cycle.

I'll answer why a bacteria would do this.

  • Symbiosis: this bacteria needs the help of another bacteria which only lives in aerobic zones and feeds on glucose. These bacteria exchange food and air for protection or some mineral/amino acid which can't be gathered or produce by the first bacteria.
  • Predation: these bacteria eat another bacteria that only live in aerobic zones, so it uses its oxygen and glucose as a trap.

Is it feasible that a bacteria or plant-like organism alter this process to further process that water into oxygen, and why would it do this?

No. That would consume more energy than the organism gets from the process to start with.

The chemosynthetic process you describe is incomplete. Tube worm chemosynthesis consumes oxygen, in the reaction

18H2S + 6CO2 + 3O2 → C6H12O6 + 12H2O + 18S

Essentially, it produces the energy to fix carbon dioxide by burning some of the hydrogen sulfide, instead of getting that energy from sunlight.

Another sulfide-consuming chemosynthetic reaction which doesn't require external oxygen inputs is

3H2S + 6CO2 + 3H2O → C6H12O6 + 3SO3

Which works because hydrogen likes being bonded to oxygen more than it likes being bonded to sulfur, and sulfur likes being bonded to oxygen more than it likes being bonded to hydrogen, so organisms employing this strategy are essentially using CO2 as an oxidizer to burn H2S.

Theoretically, you could use some of the energy from these oxidation-reduction reactions between CO2 and H2S to split oxygen out of water instead of fixing CO2--but there is absolutely no reason for a chemosynthetic organism to do that. It's a waste of energy that doesn't create any useful products. If the organism could use the oxygen as an oxidizer, then it would do so, increasing the efficiency of its chemosynthetic process, and it would be better off generating the oxidized waste products more directly, which is exactly what sulfate-producing chemoautotrophs actually do. And if it can't, then it's just creating a dangerous poison for no reason.


One process that can separate the elements oxygen and hydrogen from water is the electrolysis and it only would be possible if this plant-like or bacteria is able to polarize the water in cathode and anode like a magnet or be sitting in the top of a natural magnet while receiving an electric charge.

We also know that is possible to produce Electricity through chemical reactions, as for example batteries or even by friction to create static electricity.

Also, Oxygenic photosynthesis, the process by which certain organisms use the energy of sunlight to convert carbon dioxide and water into sugar for food, with oxygen as a by-product is a good option as you have it and water as by-products of the Chemosynthesis.

I would say it is possible, just use your preferred combination of these elements to build your oxygen.


It is possible

In photosynthesis, photolysis enables water to be dissociated into hydrogen ions and oxygen. It is standard-issue on most photosynthetic plants in the light-dependent stage of photosynthesis, and therefore it is not a particular stretch for an organism to alter itself to have this type of functionality, especially through genetic modification, etc.

Insofar as why this would be a practical, or even useful modification, could be an interesting question. Such a process could, like in the light-dependent stages of photosynthesis, directly generate ATP by creating a proton gradient (by which ATP synthase can function), bypassing the production of glucose and its subsequent breaking down during cellular respiration. The mathematical practicality of this is unclear, but biology is not always most effective and hence such a process could potentially work.

  • $\begingroup$ Photolysis very explicitly is not a stage in chemosynthesis. $\endgroup$ May 25, 2023 at 18:00
  • $\begingroup$ @LoganR.Kearsley The question asks "Is it feasible that a bacteria or plant-like organism alter this process to further process that water into oxygen" - implying that the process does not need to remain within the ordinary confines of chemosynthesis. It is not a stretch to take a process from photosynthesis if it is appropriate for the confines of the question. No stage of chemosynthesis converts water to O2 anyways. $\endgroup$
    – dreamforge
    May 25, 2023 at 20:31

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