icrobial Fuel CellThe future of Bio-energy…M Vishal .V. DoshiMs in Molecular Biology (Contd.),Skövde University,Skövde-54162,Sweden.
What is Microbial Fuel Cells (MFC) ?A microbial fuel cell (MFC) converts chemical energy, available in abio-convertible substrate, directly into electricity. To achieve this,bacteria are used as a catalyst to convert substrate into electrons.A typical microbial fuel cell consists of anode and cathodecompartments separated by a cation (positively charged ion)specific membrane. In the anode compartment, fuel is oxidizedby microorganisms, generating electrons and protons.In general, there are two types of microbial fuel cells: mediator andmediator-less microbial fuel cells.
Why Microbial Fuel Cells (MFC) ?• Unlimited supply of fuel• No reliance on foreign oil• Little or no pollutants• Much higher energy conversion %• No moving parts• No noise
Anode Chamber– Stores fuel--> Cathode Chamber– Exposed to air<-- Membrane - Allows for H+ passage^ Often Platinum CatalystV V
Examples of microbial-based fuel cellsMicrobe Substrate Mediator Anode VoltageE.coli Glucose MethyleneBluePt- C-cloth 625mVBacillussubtilisGlucose Thionine VitreousCarbon640mVE.coli Acetate Neutral red Graphitefelt250mVPseudomonasmethanicaMethane 1-Naphthol-2-Sulfonate indo-2,6dichlorophenolPt-black 550mVProteusvulgarisSucrose Thionine Carbon rod 350mV
Molecular BiologyA General layout of a MFC in which in the anodiccompartment the bacteria can bring aboutoxidative conversions while in the cathodiccompartment chemical and microbial reductiveprocesses can occur.(After Rabaey & Verstraete,2005)Mediator Shuttling ElectronsMediator-less
Molecular BiologyMediator-lessETC in Prokaryotes
Molecular BiologySummary of componentsproposed to be involvedin the electron transportfrom cells to the anode inMFCs using metalreducing microorganisms(Geobacter species).(Figure drawn withmodifications after Lovleyet al., 2004.)
Significant Factors AffectingMFC Operation Type of electrodes Surface area of electrodes Use of catalysts Conc. of hydrocarbon in anode chamber Agitation of hydrocarbon molecules Rate of replacement of hydrocarbons Types of microbes/enzymes Conc. of microbes/enzymes