photosynthetic heterotrophs - I cant remember their name.. (Aug/22/2008 )
I am planning to do research involving mutagens, and I need to find out the name of some species that can either be auto trophs or heterotrophs, depending on the situation. I am sure there is some specie that, when held in a jar, turns green only in the presence of sunlight, as it is heterotrophic when in the dark. I just cant remember the name, and I would be VERY grateful if someone reminded me, as my bio book is back home.
As concepts, there is no overlap in a Venn sense and in fact the definitions considered in the sense of primary metabolism are largely correct. There are certainly organisms (for example Euglena gracilis) that can express both. However, photosynthesis is its primary mode.
Could you possibly specify the reverse- a bacterium that primarily metabolizes organic molecules, but can go on to photosynthesis when there is no food? As for euglena, I have no idea.. I will have to do some studying. For instance, can euglena grow in low sunlight, provided there is sufficient food?
I ask such pointed questions with a purpose- creating a coal-eating bacteria. From coal, to protein. And so, this bacterium would have to be able to create its own amino acids and such..
you might also want to look at Rhodobacter capsulatus and related Rhodobacter species. Rhodobacter are quite metabolically versatile. Its phosphosynthetic apparatus is is primarily regulated by oxygen tension. Rhodobacter can switch from aerobic respiration to anoxygenic photosynthesis in the absence of oxygen.
What do you mean by "coal" and"coal eating"? This is not a single organic molecule. There is a huge database on bacterial and fungal metabolism of organic components in coal. Very little of it involving photosynthetic microbes.
Oh really?? It would be great if you could post some links. I suppose I could google it too.
The reason I would like to use photosynthetic microbes is that perhaps adding sunlight would increase the efficiency of the process between the times these microbes split. As in, not all the energy the bacteria need would come from the coal, and so the yield would be higher. I learned from biology that only about 5-10% of energy absorbed in an energy tier (on a food web) is passed on to higher tiers, and maybe coal could be used as a carbon source only.. (although there are probably cheaper sources of carbon)
At the same time, using a pure heterotroph would make the process a lot simpler, and this way could be done by anyone with a barrel and microbe samples, allowing for easy scaling.
To pereseblue:
I am still reading up on rhodobacter, and it seems like a good candidate. It grows in films, as well as individually I believe, reducing the need to pulverize the coal too much. It can fix it's own nitrogen, reducing the amount of growth solution necessary in each bio reactor, and it has many metabolic pathways that could be explored. At the same time, it does not synthesize its own amino acids, meaning they would have to be added.
Do you, by any chance, know where I could order some?
I am still reading up on rhodobacter, and it seems like a good candidate. It grows in films, as well as individually I believe, reducing the need to pulverize the coal too much. It can fix it's own nitrogen, reducing the amount of growth solution necessary in each bio reactor, and it has many metabolic pathways that could be explored. At the same time, it does not synthesize its own amino acids, meaning they would have to be added.
Do you, by any chance, know where I could order some?
Well one of the first places to look is ATCC collection. If you look under bacteria and search for "rhodobacter", you find the 47 isolates that they have.
EDIT: Just curious, why are you engineering a bacteria to eat coal? It sounds quite ambitious.
Please say more about the objective of this work. Anyone with a barrel and a microbe would render what useful product - carbon in what form?
And please remember this is a technical forum - not a place for environmental rants.
And please remember this is a technical forum - not a place for environmental rants.
With the appropriate bacteria it may be possible to turn coal into protein. I do not know if mammals are able to digest all types of microbes- this is another factor when choosing bacteria. Assuming most people do not want to eat bacteria just yet, this would be a process for turning coal into high-protein animal feedstock.
Thanks - so the idea is use of coal for production of feedstock protein. I suppose it is feasible but I sure wonder if photosynthetic operations or fermentation of agricultural byproducts would be more efficient and safe - prob more acceptable to folks as well.