Search Results - derek+lovley

The present invention reports the conductive properties of Geobacter sulfurreducens pili (geopili) and their use in nanotechnology applications. More specifically the present invention provides methods for culturing cells of G. sulfurreducens to produce conductive pili, as well as methods for their isolation and for their modification in order to produce biological nanowires or biological/inorganic hybrid devices with different functionalities.  The invention provides applications for cells expressing native or modified pili as well as for the isolated native or modified pili.

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.

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.

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.

In bioremediation, geobacter sulfurreducens can render toxic uranium and halogenated compounds safe through reduction. For MFCs, geobacter can transfer electrons to the surface of an electrode, resulting in electric current production. MFC technology possesses many advantages over other fuel cell technologies, especially in its low costs, long lifetime, sustainability, and environmental safety.

However, these two applications are limited because wild-type geobacter sulfurreducens has a limited range of carbonaceous sources that it is able to oxidize to produce electrons (e.g. acetate, hydrogen, and some aromatic compounds). 

In this patented invention, Dr. Lovley’s lab group has genetically engineered novel strains of Geobacter sulfurreducens that can utilize oxygen-rich molecules (i.e., sugars and glycerol) to generate electricity. These energy-dense molecules are present in large quantities in the waste streams of sewage treatment, biodiesel production, and agricultural processes. This invention vastly expands the economic and environmental benefits and applications of bioremediation and MFCs.