Search Results - kelly+nevin+lovley

With rapidly increasing proliferation and declining costs of renewable energy generation, methods of storing excess electricity become increasingly important. One such method was previously patented by Dr. Derek Lovley and Dr. Kelly Nevin. In their patented method, microorganisms use electricity to convert water and carbon dioxide into multi-carbon chemicals and fuels, akin to the reverse operation of a microbial fuel cell. This invention builds upon the inventors’ patent. Here, they created a genetically-modified strain of Geobacter sulfurreducens, whose electrical current consumption rate is more than 10x higher than the wild-type strain, greatly enhancing the conversion process. This new strain also provides a platform for producing a wide variety of high-value carbonaceous products previously not possible through this method.

Concerns of resource supply and climate change motivate the shift away from fuels and chemicals derived from fossil fuels towards domestic, sustainable production. The inventors’ patented technology presents a new way of doing this, using microorganisms that are able to take in CO2, water, and electricity and synthesize carbonaceous fuels and chemicals, akin to a reverse microbial fuel cell.

 

In “microbial electrosynthesis,” a term coined by the inventors, an anode and cathode are connected to a source of electrical power and separated by a permeable membrane. Electron-accepting microorganisms are coated on a cathode, where they reduce CO2 to multi-carbon products, while water is oxidized to oxygen at the anode. For example, the production of acetate would proceed as follows:

 

Anode: 4H₂O --> 8H⁺ + 8e^- + 2O₂

Cathode: 2CO₂ + 8H⁺ + 8e^- --> CH₃COOH + 2H₂O

Overall: 2CO₂ + 2H₂O --> CH₃COOH + 2O₂

 

In addition to acetate, production of ethanol, butanol, propanol, formate, and 2-oxobutyrate have been demonstrated.

Microbial fuel cells (MFCs) convert organic matter into electrical energy, and find applications in electricity generation and sensor powering for soil, salt and fresh water, and commercial waste environments. Typically, the anode chamber of the MFC must be kept under anaerobic conditions because of anoxic requirements for the bacteria. This both increases engineering costs and impedes proton transfer from the anode to the cathode.

 

Dr. Kelly Nevin Lovley and Dr. Derek Lovley patented an aerobic MFC anode electrode, allowing for the aerobic operation of an MFC. In their single-chambered design, an internal reservoir of fuel-bearing liquid is created at the anode. The anode is porous, allowing the fuel (e.g. acetate) to diffuse out and form a thick layer. At the outer layer of biofilm, oxygen will be reduced to water and the acetate fuel will be oxidized to CO2. This outer layer protects the inner layer from rapid oxidation, allowing the bacteria to generate current for weeks at a time.

Geobacter sulfurreducens is considered to be a leading candidate for use in microbial fuel cells (MFC). Geobacter clearly outperforms organisms such as Shewanella and Rhodopherax in growth characteristics and the ability to produce electric current. However, Geobacter-based microbial fuel cells still do not produce sufficient powder densities for practical applications.

UMass microbiologist Derek Lovley and his colleagues have developed a novel Geobacter strain "Neo" that has been specifically adapted to a fuel cell environment. By maintaining a high selection pressure in the microbes' environment, the original wild type strain was coerced to adapt by developing new characteristics appropriate for commercial MFC operation, including a 600% increase in current production.