Genetically engineered microbial biosensors have yet to realize commercial success in environmental applications due, in part, to difficulties associated with transducing and transmitting traditional bioluminescent information. Bioelectrochemical systems (BESs) output a direct electric signal that can be incorporated into devices for remote environmental monitoring. Here, we describe a BES-based biosensor with genetically encoded specificity for a toxic metal. By placing an essential component of the metal reduction (Mtr) pathway of Shewanella oneidensis under the control of an arsenic-sensitive promoter, we have genetically engineered a strain that produces increased current in response to arsenic when inoculated into a BES. Our BES-based biosensor has a detection limit of ~40. μM arsenite with a linear range up to 100. μM arsenite. Because our transcriptional circuit relies on the activation of a single promoter, similar sensing systems may be developed to detect other analytes by the swap of a single genetic part.
Bibliographical noteFunding Information:
The authors would like to thank Spencer Chen, Steven Chen, Charlie Chung, Danielle Huang, Rafael Lizarralde, Jim Mathew, Claire Paduano, Shweta Patro, Chie Shu, Mark Simpson, and Tina Su for assisting with benchwork; Drs. Shivaun Archer, Matthew DeLisa, Gene Madsen, and Xiling Shen of Cornell University for providing strains and laboratory resources; and Ali Awan, Elliot Friedman, Taylor Stevenson, and Dr. Didi Waraho for providing helpful advice on experimental methods. In addition, the authors appreciate the work of Maneesh Gupta, Daniel Levine, Kelvin Luu, Paras Sanghavi, Manuel Valdez, Lydia Wang, and Robert Zhang of the 2012 Cornell iGEM Drylab team. The authors declare no conflicts of interest. This work was financially supported by the Oil Sands Leadership Initiative as part of the 2012 International Genetically Engineered Machines Competition, by an NSF CAREER grant ( 0939882 ) to Largus T. Angenent and by an Office of Naval Research grant ( N00014-12-1-0309 ) to Jeffrey A. Gralnick.
- Bioelectrochemical system (BES)
- Continuous monitoring
- Microbial biosensor
- Synthetic biology