There is a large global effort to improve microbial fuel cell (MFC) techniques and advance their translational potential toward practical, real-world applications. Significant performance breakthroughs cannot be achieved through naturally existing species without the power of genetic engineering techniques, whether by maximizing a specific organism's electrogenic potential, stitching together genes involved in electrogenesis from various organisms, or developing a bacterial electrogenic consortium.
Although substantial research has been conducted on genetic engineering of microbial metabolic pathways for biofuel generation, genetic approaches for higher electricity generation remain quite limited. This is mainly due to limitations in current screening methods for bacterial electrical properties, even though microbial biofuel-producing capacity can be assessed with well-established microarray techniques that monitor gene expression under different growth conditions and detect specific DNA mutations.
Microbial screening arrays for bioelectricity generation require much more complicated device configurations and fabrication than general microbial microarrays. They often need an active feeding system and dual chambers separated by a proton exchange membrane, whereas standard microbial microarrays typically use only one chamber and do not require electrical measurements. Recently developed MFC arrays also have complex architectures with many tubing and channel connections that operate with external pumps, constraining the number of distinct wells on the array to only 24.
If a 24-well MFC array were designed with a two-chamber configuration requiring individual anolyte and catholyte inlets and outlets, 96 tubing ports and fluidic pathways would need to be implemented and operated by several multichannel syringe or peristaltic pumps. Electrical contacts for characterization of each MFC unit further increase the complexity of the device architecture. In addition, each MFC unit requires a long start-up time for bacterial accumulation and acclimation as biofilms adhere to the anode.
These limitations motivated us to develop a new conceptual MFC array that significantly improves high-throughput and rapid power assessment with a compact and simple device design. Currently, we are developing a paper-based microbial sensor array as a high-throughput, rapid screening tool for microbial electricity generation studies.