As you already know, Earth’s ecosystems are in a closed-loop. Researchers from the University of Birmingham have created a closed loop hydrogen energy eco-system based on two types of bacteria and a twist of fuel cell technology. How did they do that?
According to an article from the August issue of “Microbiology Today”, they combined two types of bacteria to produce hydrogen by two different means. One bacteria feeds with the other’s leftovers, each producing hydrogen in its own way. The final “dejections” are to be used in scavaging precious metals from spent automotive catalysts, to make fuel cells that produce electricity and transform hydrogen and oxygen into water.
According to Dr. Mark Redwood from the University of Birmingham, “There are special and yet prevalent circumstances under which micro-organisms have no better way of gaining energy than to release hydrogen into their environment. Microbes such as heterotrophs, cyanobacteria, microalgae and purple bacteria all produce biohydrogen in different ways“
The researchers are studying the producing of hydrogen because it has the highest energy density (much more than petrol), and it produces no pollution.
Methane is used as a source for the much-precious hydrogen. Methane is 25% more potent than carbon dioxide in creating the greenhouse effect. The primary and most useful source of methane comes from landfills.
In the lack of oxygen the bacteria that helps fermentation uses carbohydrates like sugar to produce hydrogen and acids. There is one more bacteria type: the purple bacteria, that generates energy by photosynthesis (the energy of light, the same ways green plants do), and produces hydrogen in order to help it divide de acids coming from the other bacteria. These two reactions fit together as the purple bacteria can use the acids produced by the fermentation bacteria. Professor Lynne Macaskie’s Unit of Functional Bionanomaterials at the University of Birmingham has created two bioreactors that provide the ideal conditions for these two types of bacteria to produce hydrogen.
“By working together the two types of bacteria can produce much more hydrogen than either could alone,” said Dr Mark Redwood. “A significant challenge for the development of this process to a productive scale is to design a kind of photobioreactor that is cheap to construct and able to harvest light from a large area. A second issue is connecting the process with a reliable supply of sugary feedstock.”
“In a final twist, the hydrogenase enzymes in the leftover bacteria can be used to scavenge precious metals from spent automotive catalysts to help make fuel cell that converts hydrogen into electricity,” said Professor Lynne Macaskie. “So nothing is wasted and an important new application can be found for today’s waste mountain in tomorrow’s non-fossil fuel transport and energy.”
So this is a way we could get rid of harmful gases that our landfills emanate. Bacteria could help us in providing energy to move around, even if the process of photosynthesis is not an efficient one. The other way of doing it more nicely and without biohazards would be to generate hydrogen and use it as a solar energy collector (sun -> solar panel -> electrolysis -> hydrogen). Having greater energy per liter than petrol, and being much more clean than a battery, it is a more viable way of doing the world a long-term good. Recycling is another story, and the landfill gas capturing and hydrogen producing fits much more like a small-sized patch for both the planet’s energy needs and global warming cautions.