my question is inspired by @Renan comment in this question Can a naturally occurring milk river exist? and so i think i want to incorporate it for my blood river from my old question what organs or modification needed to have plants that drink liquid blood? since it look more awesome and more believable, my original one is to gruesome.

but i want to know can bacteria/microorganism make such thing or not biologically or scientifically, since i am not knowledgeable about biology or microbiology. and i dont mean sucking other animal blood and then pouring it out, since it kinda feel similar to my original one. and so what i mean is the bacteria/microorganism producing the blood like bone marrow do for example, except they are small like bacteria, and excrete it or something like that for a reason.

and i dont mean dye material that make the water look red, but real red blood (blue or other color is also fine if red cant do)

also i mean bacteria/microorganism that is outside of creature body rather than the one that only remain inside other creature.

if possible, please also include how to contain such bacteria/microorganism, like temperature, or salinity, etc, since i dont want it to spread to entire world but only exist in this certain region.

feel free to correct my grammar and the tag to the appropriate one.

  • $\begingroup$ Don't you think that whatever hints you get here, to be comfortable writing that scenario will mean you have to read between one and half a dozen technical texts at or above senior high-school level? Why not just read the books first? $\endgroup$ Aug 9, 2020 at 18:36
  • $\begingroup$ @RobbieGoodwin i dont get what you mean? beside each country have different standard regarding above senior high school level, for example i was one of the highest rank in english but even i notice how english speaker in internet consider mine as horrible (at least thats what they always bring up when they argue with me). besides if i understand microorganism and advance biology i may not even ask here or making the question at all. also i am not scientist or smart like some genius i am just average person that fascinate by history. beside the answer explanation seem easier to understand. $\endgroup$
    – Li Jun
    Aug 10, 2020 at 4:59
  • $\begingroup$ @RobbieGoodwin and before you think or accuse me of not even try to search, i did using google to check but no result so far for me. $\endgroup$
    – Li Jun
    Aug 10, 2020 at 5:00

3 Answers 3


Blood cells are unicellular, by definition. Bacteria are unicellular organisms so they can't produce blood cells unless they divide into blood cells via mitosis which is a catch 22 because it means they needed to be blood cells to begin or some kind of cell that can undergo mitosis and then turn into a blood cell. In humans (all mammals, apparently), these are stem cells since blood cells lose their nucleus so they can't divide undergo mitosis anyways.

Multi-cellular micro-organisms? They can make whatever you want them to...I guess.

Blood also contains more than just blood cells. Mainly plasma and other junk which microorganisms, including bacteria could synthesize if you really wanted them to.

For such a concentrated mass of blood to exist though is a problem. For it to be the product of microorganisms thriving in it, they have to be getting something out of making it. Otherwise it would be like alcohol where they make it but it is just a waste product that is killing them at the same time. It would almost have to be an ecosystem of some kind which starts to preclude it from being just blood.

If the organisms aren't actually living in the blood, and just producing it then it is probably a waste product and you have to wonder why they make so much of it. You would need almost entire mountains of these things seeping the waste blood out of the ground and having it collect in rivers to flow.

And in both cases you have to wonder where they are getting all the resources to pump this blood out, especially in the case where they are living in it at the same time since they would be surrounded by blood, and not the stuff used to make blood.

It's almost easier to make them be trees or something and have an excuse that there's too much iron in the ground so the trees have to process it somehow in a way that it doesn't just go back into the soil around them, and preferably travel far away from the tree.

  • 1
    $\begingroup$ There's also the issue that blood contains many different kinds of cells. Both red and white, at the simplest. $\endgroup$
    – Mary
    Aug 8, 2020 at 16:14

The organisms would play the role of the red blood cells.

red tide


These red tide microorganisms are red because of accessory photosynthetic pigments. They are like blood in that blood cells consist of little envelopes of biological material containing pigment molecules, and the micro-organisms making up this red tide are that as well. The micro-organisms are of course much more robust and independent than red blood cells. Red blood cells are dependent on the organism for protection ,energy etc but each of the micro-organisms in the red tide is a formidable solo act, fully capable of going it alone in the hard world.

Could you have a microbe which was red because it produced hemoglobin? Sure. Bacteria have been engineered to make recombinant hemoglobin. Legumes use hemoglobin (leg hemoglobin) to protect their commensal nitrogen fixers from oxygen. I could imagine something like an anaerobic photosynthesizer which protected itself from oxygen with hemoglobin in the same way, and it would be red.

No-one is going to take a transfusion of these red cells. But they might be tasty like meat - that leghemoglobin mentioned above is used to give the new plant burgers their meaty taste.


Definitely not normal Bacteria:

I'm going to narrow my focus on how a bacteria could replicate the iconic part of blood that makes it "blood." The red blood cell. Actual whole blood is a complex mixture that would require a matrix of replicating pluripotent eukaryotic stem cells and other additional factors a little more complex than can be dealt with here.

By definition, bacteria are prokaryotic organisms. They are genetically simple (yes, that's a loaded term) and don't have a nucleus. Their existence is driven by replication. Most (with a few exceptions) are tiny compared to eukaryotic cells. So how would a simple prokaryotic organism make a complex eukaryotic cell?

This is not as bad of a question as it seems on first glance. Red blood cells in humans don't have a nucleus. There are very few cells that don't. They can't replicate on their own and derive from nucleated red cells that have their nuclei removed. Most bacteria other than Mycobacteria have cell walls to cope with osmotic pressure from their environment. Mycobacteria are often intracellular parasites and tend to have even simpler genomes than most bacteria because they are depending on their hosts for biosynthesis. So how does a tiny, super-simple cell become something immense and complex? There are also some big bacteria but these tend to be highly specialized to exotic environments. For something as small and simple as most bacteria to make a red blood cell, they would need to work as a team. Many bacteria can organize themselves into multicellular structures that seem to carry out more complex tasks, but are generally not considered truly multicellular.

The biggest barrier in all this to having bacteria making blood is energy. The bacteria would not have the genome to make blood, or the manufacturing capacity to do so, but most critically there is no energetic advantage to making these huge, expensive, non-replicating red cells. Even if the bacteria could, they would need to be kept in a bioreactor of some sort with massive inputs of nutrients. Scientists certainly make genetically engineered bacteria that can produce large amounts of simple excreted materials, but the advantage is that the organism survives because the scientist "rewards" the species with survival for producing what they want.

If you need to go as far as having a bioreactor to produce red blood cells, you're better off growing pluripotent stem cells in culture, then forcing them to mature into red blood cells through maturation signals. It wouldn't (won't?) surprise me when scientists start using just this approach to produce blood outside the body for transfusion purposes. Specialized cells lacking surface antigens to minimize antibody interactions will probably replace blood donations eventually.

So you can have animals making blood (Maybe even unicellular ones, but at that point they're essentially stem cells). You can have bacteria making something that looks like blood but isn't. You can have bioreactors that crank out the cells for blood, and you could probably have bacteria make a lot of the plasma components for blood. I don't see how the bacteria could or would make blood on their own.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .