NITRATE BIOSENSOR

This research topic targets a novel sensing approach for sparing the fossil energy resources massively used in agriculture. The production of nitrogen fertilizer alone consumes up to 5% of the global natural gas production. These fertilizers are applied in excess in the field and lost in the form of nitrates. Our group addresses this issue by developing sensors to determine the nitrate content in plants directly in the field by the farmers themselves to provide the information on the plants’ need to adjust the fertilizer input in real-time1. The democratization of the use of such sensors requires simple procedures for on-site nitrate quantification without sample preparation. To this end a redox enzyme that selectively reduces nitrate2 is contacted via artificial electron relays to single-use electrodes. The main interferences in this sensing concept when brought from the lab to field applications is oxygen from air. To overcome this issue, we develop universal oxygen scavengers that are compatible with biochemical and electrochemical processes. The principal challenge resides in designing an oxygen reduction reaction that results in fully inert products3. Enzymatic oxygen scavengers based on carbohydrate oxidation are most promising and we selected the enzymes catalase and pyranose oxidase to reduce oxygen with glucose to water. Such O2 scavenging systems maintain tiny volumes (down to 20 µL) under anaerobic conditions for hours, even when exposed to ambient air. The conditions of the systems such as pH value or biological activity are not affected by the oxygen reduction product4,5. We demonstrated that the oxygen scavenger system associated to the nitrate biosensing concept allow for fast, simple and reliable nitrate quantification on the field.
The impact of the nitrate biosensing method to spare fossil ressources and to eventually reduce CO2 emission was recently recognized by KlimaExpo.NRW who made it a priority topic to encourage and educate about climate protection6. The method is awaiting validation of a pending patent application7.

Nitrat Biosensor

  1. Plumeré N., Nachrichten aus der Chemie 2014, 62(7), 777-779.
    DOI: 10.1002/nadc.201490261

  2. Campbell W. H., Henig J., Plumeré N., Bioelectrochemistry, 2013, 93, 46-50.
    DOI: 10.1016/j.bioelechem.2012.07.002

  3. Plumeré N., Analytical and Bioanalytical Chemistry, 2013, 405(11), 3731-3738.
    DOI: 10.1007/s00216-013-6827-z

  4. Swoboda M., Henig J., Cheng H.-M., Brugger D., Haltrich D., Plumeré N., Schlierf M., ACS Nano, 2012, 6(7), 6364-6369.
    DOI: 10.1021/nn301895c

  5. Plumeré N., Henig J. and Campbell W. H., Analytical Chemistry, 2012, 84, 2141-2146.
    DOI: 10.1021/ac2020883

  6. Plumeré N.,Nitratsensor: Schluss mit Überdüngung - Feldanalytik in der Landwirtschaft.
    KlimaExpo.NRW Motor für den Fortschritt

  7. Plumeré N., Campbell W. H., Campbell E. R., Systems and Methods for Enzymatic Oxygen Removal.
    US2012211372 (A1) - 2012-08-23