Microbial Biofuel Cells

A microbial fuel cell schematic where bacteria in an anodic compartment can bring about oxidative conversions, while in the cathodic compartment, chemical and microbial reductive 

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Microbial biofuel cells were the earliest biofuel cell technology to be developed, as an alternative to conventional fuel cell technology. The concept and performance of several microbial biofuel cells have been summarized in recent review chapters." The most fuel-efficient way of utilizing complex fuels, such as carbohydrates, is by using microbial biofuel cells where the oxidation process involves a cascade of enzyme-catalyzed reactions. The two classical methods of operating the microbial fuel cells are (1) utilization of the electroactive metabolite produced by the fermentation of the fuel substrate " and (2) use of redox mediators to shuttle electrons from the metabolic pathway of the microorganism to the electrodes. ... 

In contrast to microbial biofuel cells, enzymatic biofuel cells utilize the redox enzymes rather than the whole microorganism as a biocatalyst. The redox enzyme, which is separated and purified from an organism, participates in the electron transfer chain that occurs between the substrate and the anode by oxidizing the fuel or between the substrate and the cathode as shown in Figure 1.10. 

Recently, a novel microbial fuel cell harvesting energy from the marine sediment—seawater interface has been reported. Also, a novel photosynthetic biofuel cell that is a hybrid between a microbial and enzymatic biofuel cell has been reported for the very first time. More recently, reports of an unconventional biomass-fueled ceramic fuel cell can also be found in the literature. A new concept of Gastrobots —hybrid robots that utilize operational power derived from microbial fuel cells—has been introduced. Finally, the generation of electrical power by direct oxidation of glucose was demonstrated in mediatorless microbial fuel cells, which produced currents up to 3 fiA/cm at unknown cell voltage. ... 

Biofuel cells — also referred to as biochemical, or bio-electrochemical fuel cells, exploit biocatalysts for the direct conversion of chemical energy to electrical energy. Based on the nature of the biocatalyst, biofuel cells are generally classified as enzymatic fuel cells and microbial fuel cells [i]. Enzymatic fuel cells use purified enzymes to catalyze the oxidation of substrates at the - anode and... 

Biofuel cells — Figure. Schematic illustration of identified electron transfer mechanisms in microbial fuel cells. Electron transfer via (a) cell membrane-bound cytochromes, (b) electrically conductive pili (nanowires), (c) microbial redox mediators, and (d) via oxidation of reduced secondary metabolites [v]... 

The concept of biofuel cells was briefly mentioned in Chapter 2, section 2.1.6, where microbial sensitisers were employed in photoelectrochemical devices. 

Scientists have studied the use of microbes as biofuei ceiis. A biofuel cell directly converts microbial metabolic energy into electric current. An electron mediator facilitates transfer of electrons to an electrode. An electron mediator is a compound that taps into the electron transport chain of cells and steals the electrons that are produced. 

Bernard O, Remond B Validation of a simple model accounting for light and temperature effect on microalgal growth. Bioresource Technology (Special Issue Biofuels -11 Algal Biofuels and Microbial Fuel Cell) 123 520—527, 2012. 

Rabaey, K., Lissens, G., Verstraete, W. (2005). Microbial fuel cells performances and perspectives. In P. Lens, P. Westerman, A. Haberbauer, A. Moreno (Eds.), Biofuels for fuel cells Renewable energy from biomass fermentation. London IWA Publishing. 

Rabaey, K., Boon, N., Hofte, M., and Verstraete, W. (2005) Microbial phenazine production enhances electron transfer in biofuel cells. Environ. Sci. Technol, 39 (9), 3401-3408. 

Rabaey K, Boon N, SicUiano SD, Verhaege M, Verstraete W. Biofuel cells select for microbial consortia that self-mediate electron transfer. Appl Environ Microbiol 2004 70 5373-5382. 

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