Bioelectrogenesis

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The electric eel uses electric shocks for both hunting and self-defense. Electric-eel.jpg
The electric eel uses electric shocks for both hunting and self-defense.

Bioelectrogenesis is the generation of electricity by living organisms, a phenomenon that belongs to the science of electrophysiology. In biological cells, electrochemically active transmembrane ion channel and transporter proteins, such as the sodium-potassium pump, make electricity generation possible by maintaining a voltage imbalance from an electrical potential difference between the intracellular and extracellular space. [1] The sodium-potassium pump simultaneously releases three sodium ions away from, and influxes two potassium ions towards, the intracellular space. This generates an electrical potential gradient from the uneven charge separation created. The process consumes metabolic energy in the form of ATP. [2] [3] [4]

Contents

Taxonomic distribution

Bioelectrogenesis in the form of creating voltages across membranes is universal in living cells, as this is central to the way that cells provide themselves with usable energy, chemiosmosis, and has been since at least the time of the last universal common ancestor (LUCA). The capability is accordingly found in archaeans, bacteria, and eukaryotes including animals, plants, and fungi. [4] [5] [6]

In fish

All fish, like other vertebrates, make use of electrical activity in their nerves and muscles. Some groups of fish have adapted this feature to provide additional capabilities, namely electroreception and the ability to stun prey. Electric fish include some Torpedinidae (electric rays) and Rajiformes (skates) of the class Chondrichthyes, and some Teleosts, in the Mormyriformes (elephant nose fish), Gymnotiformes (knifefish), Siluriformes (catfish), and the Uranoscopidae (stargazers). [7] [8] These fish produce electric currents through their electric organs, which are composed of electrocytes, modified muscle tissue which allows large concentrations of Na+ ions to pass through the cell membrane. [8] The cumulative effect of this process is an electric discharge. These fish are also usually electroreceptive, like a much larger number of species which are weakly electric, mainly for electrolocation of prey. [8] Electrogenesis may be utilized for electrolocation, self-defense, electrocommunication and sometimes the stunning of prey. [9]

In microbes

The first examples of bioelectrogenic microbial life were identified in brewer's yeast (Saccharomyces cerevisiae) by M. C. Potter in 1911, using an early iteration of a microbial fuel cell (MFC). It was founded that chemical action in the breakdown of carbon such as fermentation and carbon decomposition in yeast is linked to the production of electricity. [10]

Decomposition of organic or inorganic carbon by bacteria is paired with the release of electrons extracellularly towards electrodes, which generate electric currents. The microbe's released electrons are transferred by biocatalytic enzymes or redox-active compounds from the cell to the anode in the presence of a viable carbon source. This creates an electrical current as electrons move from anode to a physically separated cathode. [11] [12]

There are several mechanisms for extracellular electron transport. Some bacteria use nanowires in biofilm to transfer electrons towards the anode. The nanowires are made of pili that act as a conduit for the electrons to pass towards the anode. [13] [14]

Electron shuttles in the form of redox-active compounds like flavin, which is a cofactor, are also able to transport electrons. These cofactors are secreted by the microbe and reduced by redox participating enzymes such as Cytochrome C embedded on the microbe's cell surface. The reduced cofactors then transfer electrons to the anode and are oxidized. [15] [16]

In some cases, electron transfer is mediated by the cellular membrane embedded redox participating enzyme itself. Cytochrome C on the microbe's cell surface directly interacts with the anode to transfer electrons. [17] [18]

Electron hopping from one bacteria to another in biofilm towards an anode through their outer membrane cytochromes is also another electron transport mechanism. [19]

These bacteria that transfer electrons in the microbe's exterior environment are called exoelectrogens. [16]

Electrogenic bacteria are present in all ecosystems and environments. This includes environments under extreme conditions such as hydrothermal vents and highly acidic ecosystems, as well as common natural environments such as soil and lakes. Electrogenic microbes such as Pseudomonas aeruginosa are observed through identification in electrochemically active biofilms formed on MFC electrodes. [20] [21]

See also

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References

  1. ↑ Elbassiouny, A. A.; Lovejoy, N. R.; Chang, B. S. W. (2020-01-20). "Convergent patterns of evolution of mitochondrial oxidative phosphorylation (OXPHOS) genes in electric fishes". Philosophical Transactions of the Royal Society B: Biological Sciences. 375 (1790): 20190179. doi:10.1098/rstb.2019.0179. PMC   6939368 . PMID   31787042.
  2. ↑ Baptista, V. (December 2015). "Starting physiology: bioelectrogenesis". Advances in Physiology Education. 39 (4): 397–404. doi:10.1152/advan.00051.2015. PMID   26628666.
  3. ↑ Schoffeniels, E.; Margineanu, D. (1990). "Cell Membranes and Bioelectrogenesis". Molecular Basis and Thermodynamics of Bioelectrogenesis. Topics in Molecular Organization and Engineering. Vol. 5. pp. 30–53. doi:10.1007/978-94-009-2143-6_2. ISBN   978-94-010-7464-3.
  4. 1 2 Schoffeniels, E.; Margineanu, D. (1990). "Cell Membranes and Bioelectrogenesis". Molecular Basis and Thermodynamics of Bioelectrogenesis. Topics in Molecular Organization and Engineering. Vol. 5. pp. 30–53. doi:10.1007/978-94-009-2143-6_2. ISBN   978-94-010-7464-3.
  5. ↑ Muller, A. W. J. (1995). "Were the first organisms heat engines? A new model for biogenesis and the early evolution of biological energy conversion". Progress in Biophysics and Molecular Biology. 63 (2): 193–231. doi: 10.1016/0079-6107(95)00004-7 . PMID   7542789.
  6. ↑ Muller, A. W. J.; Schulze-Makuch, D. (2006). "Thermal energy and the origin of life". Origins of Life and Evolution of Biospheres. 36 (2): 77–189. Bibcode:2006OLEB...36..177M. doi:10.1007/s11084-005-9003-4. PMID   16642267. S2CID   22179552.
  7. ↑ Crampton, W. G. R. (2019). "Electroreception, electrogenesis and electric signal evolution". Journal of Fish Biology. 95 (1): 92–134. doi:10.1111/jfb.13922. PMID   30729523. S2CID   73442571.
  8. 1 2 3 Bullock, T. H.; Hopkins, C. D.; Ropper, A. N.; Fay, R. R. (2005). From Electrogenesis to Electroreception: An Overview. Springer. doi:10.1007/0-387-28275-0_2. ISBN   978-0-387-23192-1.
  9. ↑ Castelló, M. E.; Rodríguez-Cattáneo, A.; Aguilera, P. A.; Iribarne, L.; Pereira, A. C.; Caputi, Á. A. (1 May 2009). "Waveform generation in the weakly electric fish Gymnotus coropinae (Hoedeman): the electric organ and the electric organ discharge". Journal of Experimental Biology. The Company of Biologists. 212 (9): 1351–1364. doi:10.1242/jeb.022566. ISSN   1477-9145. PMID   19376956. S2CID   1364899.
  10. ↑ Potter, M. C. (1911). "Electrical effects accompanying the decomposition of organic compounds". Proceedings of the Royal Society of London. Series B, Containing Papers of a Biological Character. 84 (571): 260–276. doi:10.1098/rspb.1911.0073. JSTOR   80609.
  11. ↑ Raghavulu, S. V.; Modestra, J. A.; Amulya, K.; Reddy, C. N.; Venkata Mohan, S. (October 2013). "Relative effect of bioaugmentation with electrochemically active and non-active bacteria on bioelectrogenesis in microbial fuel cell". Bioresource Technology. 146: 696–703. doi:10.1016/j.biortech.2013.07.097. PMID   23988904.
  12. ↑ Velvizhi, G.; Mohan, S. V. (April 2012). "Electrogenic activity and electron losses under increasing organic load of recalcitrant pharmaceutical wastewater". International Journal of Hydrogen Energy. 37 (7): 5969–5978. doi:10.1016/j.ijhydene.2011.12.112.
  13. ↑ Malvankar, N. S.; Lovley, D. R. (June 2012). "Microbial nanowires: a new paradigm for biological electron transfer and bioelectronics". ChemSusChem. 5 (6): 1039–1046. doi:10.1002/cssc.201100733. PMID   22614997.
  14. ↑ Gorby, Y. A.; Yanina, S.; McLean, J. S.; Rosso, K. M.; Moyles, D.; Dohnalkova, A.; et al. (25 July 2006). "Electrically conductive bacterial nanowires produced by Shewanella oneidensis strain MR-1 and other microorganisms". Proceedings of the National Academy of Sciences. 103 (30): 11358–11363. doi:10.1073/pnas.0604517103. ISSN   0027-8424.
  15. ↑ Kotloski, N. J.; Gralnick, J. A. (January 2013). "Flavin electron shuttles dominate extracellular electron transfer by Shewanella oneidensis". mBio. 4 (1). doi:10.1128/mBio.00553-12. PMC   3551548 . PMID   23322638.
  16. 1 2 Kumar, R.; Singh, L.; Wahid, Z. A.; Din, M. F. (2015). "Exoelectrogens in microbial fuel cells toward bioelectricity generation: A review" (PDF). International Journal of Energy Research. 39 (8): 1048–1067. doi:10.1002/er.3305. S2CID   94764159.
  17. ↑ Bond, D.R.; Lovley, D. R. (March 2003). "Electricity production by Geobacter sulfurreducens attached to electrodes". Applied and Environmental Microbiology. 69 (3): 1548–1555. Bibcode:2003ApEnM..69.1548B. doi:10.1128/AEM.69.3.1548-1555.2003. PMC   150094 . PMID   12620842.
  18. ↑ Inoue, K.; Leang, C.; Franks, A. E.; Woodard, T. L.; Nevin, K. P.; Lovley, D. R. (2011). "Specific localization of the c-type cytochrome OmcZ at the anode surface in current-producing biofilms of Geobacter sulfurreducens". Environmental Microbiology Reports. 3 (2): 211–217. doi:10.1111/j.1758-2229.2010.00210.x. PMID   23761253.
  19. ↑ Bonanni, P. S.; Massazza, D.; Busalmen, J. P. (July 2013). "Stepping stones in the electron transport from cells to electrodes in Geobacter sulfurreducens biofilms". Physical Chemistry Chemical Physics. 15 (25): 10300–10306. Bibcode:2013PCCP...1510300B. doi:10.1039/c3cp50411e. PMID   23698325.
  20. ↑ Chabert, N.; Amin Ali, O.; Achouak, W. (December 2015). "All ecosystems potentially host electrogenic bacteria". Bioelectrochemistry. 106 (Pt A): 88–96. doi:10.1016/j.bioelechem.2015.07.004. PMID   26298511.
  21. ↑ García-Muñoz, J.; Amils, R.; Fernández, V. M.; De Lacey, A. L.; Malki, M. (June 2011). "Electricity generation by microorganisms in the sediment-water interface of an extreme acidic microcosm". International Microbiology. 14 (2): 73–81. doi:10.2436/20.1501.01.137. PMID   22069151.
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