Screening and identification of highly active electricity-generating microorganisms in microbial fuel cells, enhancement of electricity-generating performance and research on electron transfer mechanism

Subjects: Biology >> Bioengineering submitted time 2017-09-20

骆健美

Abstract： Microbial Fuel Cells (MFCs for short) are bioreactors that use electricity-producing microorganisms as catalysts to directly convert chemical energy in organic matter (inorganic matter) into electrical energy. application prospects. The research group started and ran MFCs with sludge from Tianjin TEDA sewage treatment plant as inoculum. Multiple isolates were isolated from anode-enriched biofilms. Among them, isolates P2-A-1 and P2-A-5 showed high electrochemical activity, which were identified as Tolumonas osonensis and Kocuria rhizophila, respectively. This is the first report on the electricity production performance of this species. In addition to the optimization of electricity production conditions, the permeabilization of cells is an effective means to improve the output power of MFCs. Chemical treatment increases the adhesion efficiency of bacteria to electrodes, reduces the internal resistance of MFCs, increases cell permeability and Cell membrane fluidity increases the content of the key electron carrier CoQ10. By constructing membrane-encapsulated MFCs, cyclic voltammetry scanning of anolyte and GC-MS composition analysis, the extracellular electron transfer mechanism of the strain was clarified. Taking the model electrogenic microorganism Pseudomonas aeruginosa as the object, a series of endogenous and exogenous global transcription factors were introduced into Pseudomonas aeruginosa by global transcription mechanism engineering, and the idea of ​​metabolic engineering was used to enhance the generation of intracellular electrons and the production of extracellular electrons. Electron transfer, to explore new strategies and methods for the construction of high-yielding electroactive engineered strains. Among them, the introduction of exogenous global transcription factor IrrE can significantly improve the electrical performance and environmental stress tolerance of Pseudomonas aeruginosa. Further analysis found that the introduction of this transcription factor had a significant impact on the expression levels of genes related to central metabolic pathways, biofilm-related genes, mediator synthesis-related genes, quorum sensing systems, and general stress response-related genes. This indicates that IrrE plays a global regulatory role in host organisms. The results of the project are of great significance for enriching the diversity of electricity-producing microorganisms and improving the output power of microbial fuel cells.

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