Super Earths With Hydrogen Atmospheres!

[exchemist]

That is a good point, wasn't CO2 involved in that reaction in the paper? 

I think that was for a proposed carbon capture route, involving photosynthesis, wasn't it? (The alternative being to capture carbon from methane by the reverse of the metabolic route we are discussing.)

 

I find the web sources on the metabolism of terrestrial anaerobes rather hard to follow. Often it is not clear what the overall reaction scheme is. I did once find a clearer paper on all this but can't remember where I found it.

 

Anyway I take your general point: there do appear to be several possible pathways already established among these anaerobes, which give hope that they could be operating on planets reducing atmospheres, so long as there is liquid water and light.