Just what is Microbial Electrosynthesis?
Microbial electrosynthesis (ME) technology represents a new form of photosynthesis that uses renewable solar energy to convert carbon dioxide emissions to fuels and other useful products. Like plant photosynthesis, carbon dioxide and water are combined to produce organic compounds with the release of oxygen.
Why is ME Technology much more efficient than biomass-based energy strategies?
One reason for this is that solar technologies that are used in ME harvest solar energy 100 times more effectively than plants. Furthermore, ME technology produces organic products directly. This is much more efficient than biomass-based approaches, in which the biomass must be further processed in order to produce fuel. Biomass processing requires additional energy inputs, consumes substantial water, and generates wastes.
Are there additional environmental benefits to ME Technology?
The ME technology does not require cultivatable land and avoids environmental degradation, such as pollution of water resources, associated with intensive agricultural processes. Water utilization is a tiny fraction of that required for growing biomass.
Why convert solar energy to fuels and other chemicals?
Sunlight is the most abundant source of renewable energy. Technologies for converting solar energy into electricity is well developed and can harvest solar energy much more effectively than photosynthesis. However, solar technologies only produce electricity when the sun is shining. Storing electricity is difficult. ME technology can convert the electrical energy into chemical energy in the form of fuels and chemicals. Fuels and chemicals are easily stored and can be distributed through existing infrastructure on an as needed basis.
How does ME Technology work?
ME technology is based on the discovery made at the University of Massachusetts that some microorganisms can feed on electricity. The microorganisms live on the surface of electrodes, consuming the electrons released from the electrode as their energy source. The microorganisms use carbon dioxide in the same way that humans use oxygen. The microorganisms “breathe in” in the carbon dioxide and convert it to organic compounds that the microorganisms then “breathe out”.
What can be made?
Anything that microbes are capable or producing. Acetic acid is the simplest example of a ME product, but other products, such as the transportation fuel butanol, have also already been produced. Other short-term product targets include the compounds such butanediol, a feedstock for plastics production.
Is solar energy the only way to power ME?
Any source of electrical power can be employed. Other attractive sources are electricity generated from wind and geothermal energy.
What else is Required?
A source of electrons, typically derived from water. Water quality is not important and using wastewater as an electron source for ME is a potential wastewater disposal solution. Sulfide, a common corrosive contaminant in fossil fuels, is an alternative electron source. Therefore, it is feasible to remediate sulfide waste while simultaneously sequestering carbon dioxide.
In this video, Professor Bruce E Logan from Pennsylvania State University shows us a microbial fuel cell, a device that can extract the energy from wastewater and turn it into electricity.