Hydrogen producing bacteria - a small excerpt of what I worked on during my Bachelor Thesis

As I mentioned in an earlier post, I am a bachelor student studying biology. I missed writing something for @suesa's challenge(didn't stand a chance), but she encouraged me to write something anyway and introduce myself to the steemSTEM community. At the moment I am not working in any lab as I am about to finish my bachelor degree. There is just one homework paper left and I am through.

I was not sure what my post should be about and I haven't yet picked a paper for my homework. In the end I have decided to write about a small part of my bachelor thesis. So here we go :)

In my bachelor thesis I used to work on hydrogen producing bacteria namely E. coli. What's so interesting about hydrogen producing bacteria and why does anyone want to work on them? Simply said, it would be amazing to have bacteria that could produce large quantities of hydrogen! The reason is that hydrogen is considered a renewable energy resource and is hopefully able to replace fossil fuels in the future. Current methods used to produce hydrogen use up more energy than could be retrieved from the end product. The production also has a high cost and a negative impact on the environment. Using microorganism to produce hydrogen cheaply and environmental friendly would be awesome! The hydrogen could be used as fuel in electric cars that have a fuel cell. The tank could be filled up in a few minutes compared to electric cars with a battery, that have a long charging time. 

But as we say in Germany that is just "Zukunftsmusik". At the moment there is nothing more than basic research and we have not yet created any bacteria that fart any useful amount of hydrogen(pun intended). I wrote my bachelor thesis at the microbiology institute of my university and the group I worked in is in part researching the microbal hydrogen metabolism. As part of my research I was working on enzymes that catalyze the reduction of protons to hydrogen. Here is the reaction:

As you can see the reaction is reversible and most of the time microorganism are using up hydrogen instead of producing it. More about that later.

The enzymes involved in that reaction are called hydrogenases. Because this was a bachelor thesis I wasn't really working on the whole enzyme. I worked on a few sub units of hydrogenase 1 and 2 of E. coli. Here is a scheme of the hydrogenases in E. coli: 

Some of the subunits I worked on are HyaA and HybO, they are responsible for the electron transport from the large subunits to other parts of the organism. Where do the electrons come from? They come from the large subunit that is responsible for oxidizing hydrogen to protons and electrons. Wait a minute, are we not trying to achieve the opposite? Yes, but at this level we are just doing basic research. First we have to understand how hydrogenases work and under what conditions they're active. For example E. coli is producing hydrogen under fermentative growth wich happens in the absence of oxygen. This is important because hydrogenases are somewhat sensitiv to the presence of oxygen.

Right now scientists are working on fully understanding hydrogenases, how they mature and how the interact with each other and other components of the microorganisms. As you can see I only worked on just a small fraction of the research involved.

That's it for now. I might go further into detail in the future if you like :)