This Small Business Innovation Research (SBIR) Phase I project will demonstrate the feasibility of a revolutionary, low-cost, real-time, amperometric sensor technology based on bio-electrochemical systems. The proposed device utilizes exo-electrogen microbes to detect levels of target substances, primarily nitrate and oxygen. The sensor takes advantage of highly specific biological processes and the capability of certain microbes to transfer electrical current directly to electrodes. Because of the nature of the design, the sensor is low cost, requires no additional power, and continuously self-regenerates. These capabilities will enable sensors to be deployed in remote locations to monitor nitrate and oxygen levels in a network spanning large geographical regions. The broader/commercial impacts of this research are in the environmental management, agricultural, and defense sectors. Nitrate levels in US waterways have increased dramatically in the past half-century. Nitrate in surface water run-off from agriculture activities is a particularly serious environmental problem, creating large anoxic dead zones and straining fisheries. Tracing this pollutant is difficult because existing sensors are very expensive or short-lived and cannot cover wide areas. Maintaining optimized levels of nitrate in sustainable precision agriculture not only reduces environmental impact, it is also a critical economic issue - nitrate monitoring in run-off from cropland can help to maximize yields while minimizing expensive fertilizer inputs. Finally, once proven for nitrates, the patented sensor concept has the potential to be adapted to other substances by utilizing additional capabilities of exo-electrogenic bacteria, thus producing a new class of amperometric sensors based on bio-electrochemical phenomena.
