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Team:Bielefeld-CeBiTec/Results/rMFC/Construction
From 2014.igem.org
Module I - reverse microbial fuel cell (rMFC)
Construction of an electrobiochemical reactor
We planned to design a reactor system that is suitable to investigate the electrochemical behaviour in bioprocesses. That includes the possibility to characterize mediators and different electrode materials on the one hand and the electron uptake into the cells on the other.
During our research we discovered the H-cell reactor that seemed to meet with our needs. (Park et al., 1999)
We approached two different concepts to realize the reactor construction. One of our H-cell reactors was constructed with the possibilities given to us by the facillities of our university. We instructed the glass workshop to modify two glass bottles by adding a glass-flange. Besides that the technical workshop build the lids from stainless steel. This approach had the advantage that we could influenze the design and had to make precise design drawings especially for the connections in the lids.
The second H-cell reactor was a commercially available system by Adams & Chittenden scientific glass. The commercial system had a smaller volume and the benefit of a larger flange diameter. The necessary lids for that system were also custom design by our workshop. In figure one you can see both reactors in comparison.
Figure 2: 1 Custom designed lids that profide connections for: a pO2-electrode, a pH-electrode, an entrance for reference and working electode, air output, heating coils and acid/ base input for pH control, 2 Heating coils, 3 Clamps for the flange connection 4 Sealing rings.
Cyclic voltammetry - mediator characterization
During our experiments we used a Ag/AgCl reference electrode for measuring the working electrode potential. The counter electrode, which completes the cell circuit, was made from platinum wire. Platinum has the advantage that it is an inert conducter.
Cultivation - constant voltage
The first experiments in the H-cell reactor were performed under constant direct voltage. These experiments were performed to test the set up. We investigated if E. coli was able to grow in the needed voltage range and if the different mediators influence the cells if a small electric current is applied.
Chronoamperometry - current consumption
Figure 2: Overlay of the chronoamperometric measurements from cultivation A B and C.
Flow Cell
References
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Park, D. H.,Laivenieks, M., Guettler, M. V., Jain, M. K. & Zeikus, J.G. (1999) Microbial utilization of electrically reduced neutral red as the sole electron donor for growth and metabolic production. In: Appl. Environ. Microbiol., 65 (7), pp. 2912 - 2917.
