Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Sep 21:13:162.
doi: 10.1186/s13068-020-01800-1. eCollection 2020.

Effects of biofilm transfer and electron mediators transfer on Klebsiella quasipneumoniae sp. 203 electricity generation performance in MFCs

Yating Guo #  1 , Guozhen Wang #  1 , Hao Zhang  1 , Hongyu Wen  1 , Wen Li  1
Affiliations

Effects of biofilm transfer and electron mediators transfer on Klebsiella quasipneumoniae sp. 203 electricity generation performance in MFCs

Yating Guo et al. Biotechnol Biofuels. .

Abstract

Background: Extracellular electron transfer (EET) is essential in improving the power generation performance of electrochemically active bacteria (EAB) in microbial fuel cells (MFCs). Currently, the EET mechanisms of dissimilatory metal-reducing (DMR) model bacteria Shewanella oneidensis and Geobacter sulfurreducens have been thoroughly studied. Klebsiella has also been proved to be an EAB capable of EET, but the EET mechanism has not been perfected. This study investigated the effects of biofilm transfer and electron mediators transfer on Klebsiella quasipneumoniae sp. 203 electricity generation performance in MFCs.

Results: Herein, we covered the anode of MFC with a layer of microfiltration membrane to block the effect of the biofilm mechanism, and then explore the EET of the electron mediator mechanism of K. quasipneumoniae sp. 203 and electricity generation performance. In the absence of short-range electron transfer, we found that K. quasipneumoniae sp. 203 can still produce a certain power generation performance, and coated-MFC reached 40.26 mW/m2 at a current density of 770.9 mA/m2, whereas the uncoated-MFC reached 90.69 mW/m2 at a current density of 1224.49 mA/m2. The difference in the electricity generation performance between coated-MFC and uncoated-MFC was probably due to the microfiltration membrane covered in anode, which inhibited the growth of EAB on the anode. Therefore, we speculated that K. quasipneumoniae sp. 203 can also perform EET through the biofilm mechanism. The protein content, the integrity of biofilm and the biofilm activity all proved that the difference in the electricity generation performance between coated-MFC and uncoated-MFC was due to the extremely little biomass of the anode biofilm. To further verify the effect of electron mediators on electricity generation performance of MFCs, 10 µM 2,6-DTBBQ, 2,6-DTBHQ and DHNA were added to coated-MFC and uncoated-MFC. Combining the time-voltage curve and CV curve, we found that 2,6-DTBBQ and 2,6-DTBHQ had high electrocatalytic activity toward the redox reaction of K. quasipneumoniae sp. 203-inoculated MFCs. It was also speculated that K. quasipneumoniae sp. 203 produced 2,6-DTBHQ and 2,6-DTBBQ.

Conclusions: To the best of our knowledge, the three modes of EET did not exist separately. K. quasipneumoniae sp.203 will adopt the corresponding electron transfer mode or multiple ways to realize EET according to the living environment to improve electricity generation performance.

Keywords: Biofilm; Electricity generation performance; Electron mediators; Extracellular electron transfer; Microbial fuel cells.

PubMed Disclaimer

Conflict of interest statement

Competing interestsThe authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
a MFC-coated and MFC-uncoated were incubated for 600 h of output voltage, and the anode medium was replaced when the output voltage droped. b Polarization curve and power density curve when the output voltage of the reaches its maximum value. c Nyquist plots from electrochemical impedance spectroscopy measurements of MFC-coated (black empty circle) and MFC-uncoated (red empty circle) scanned at 0.1 ~ 100 kHz at open-circuit potential (the inset on the right is the charge transfer resistance in the high frequency region of MFC-uncoated). d Cyclic voltammograms curve of coated-MFC and uncoated-MFC
Fig. 2
Fig. 2
Protein contents of coated-MFC and uncoated-MFC. a Anolyte suspension; b Anode biofilm
Fig. 3
Fig. 3
SEM images of anode biofilm of coated-MFC and uncoated-MFC, a coated-MFC: 1st cycle, b coated-MFC: 3rd cycle, c coated-MFC: 5th cycle d uncoated-MFC: 1st cycle, e uncoated-MFC: 3rd cycle, f uncoated-MFC: 5th cycle
Fig. 4
Fig. 4
Fluorescence intensity of live and dead cells of coated-MFC and uncoated-MFC
Fig. 5
Fig. 5
a CV of the supernatant of the anode on the 1–3 cycle, b Quinones electron mediators secreted by K. quasipneumoniae sp. 20
Fig. 6
Fig. 6
Effect of three quinone electron mediators secreted by K. quasipneumoniae sp. 203 on electricity generation performance of MFCs. a The output voltage–time; b Cyclic voltammogram curve
Fig. 7
Fig. 7
Schematic diagram of the anode chamber of MFCs. a coated-MFC, b uncoated-MFC
See this image and copyright information in PMC

References

    1. Singh S, Bairagi PK, Verma N. Candle soot-derived carbon nanoparticles: an inexpensive and efficient electrode for microbial fuel cells. Electrochim Acta. 2018;264:119–127. doi: 10.1016/j.electacta.2018.01.110. - DOI
    1. Bosire EM, Blank LM, Rosenbaum MA. Strain- and substrate-dependent redox mediator and electricity production by Pseudomonas aeruginosa. Appl Environ Microbiol. 2016;82:5026–5038. doi: 10.1128/AEM.01342-16. - DOI - PMC - PubMed
    1. Ma H. Bacterial electroactivity and viability depends on the carbon nanotube-coated sponge anode used in a microbial fuel cell. Bioelectrochemistry. 2018;122:26–31. doi: 10.1016/j.bioelechem.2018.02.008. - DOI - PubMed
    1. Shi L, Dong H, Reguera G, Beyenal H, Lu A, Liu J, Yu H, Fredrickson JK. Extracellular electron transfer mechanisms between microorganisms and minerals. Nat Rev Microbiol. 2016;14:651–662. doi: 10.1038/nrmicro.2016.93. - DOI - PubMed
    1. Shi M, Jiang Y, Shi L. Electromicrobiology and biotechnological applications of the exoelectrogens Geobacter and Shewanella spp. Sci China Technol Sci. 2019;62:1670–1678. doi: 10.1007/s11431-019-9509-8. - DOI

LinkOut - more resources