Microbial Fuel CellsUsing microorganisms to generate energyWhat it is!Converts chemical energy to electrical energy by the catalytic reaction of microorganismsExact same principle as a voltaic cell, only using the respiration of bacteria to generate electricityNeed of MFCMicrobial Fuel Cell!"#$o very great issues are daunting scientists today%the fuel crisis and bio $aste disposal #he ans$er to both these problems may be provided by our planet&s smallest creatures " bacteria'&Microbial Fuel Cell& MFC! can help convert bio%$aste into electricityMicrobial Fuel Cell"masticatedscience'$ordpress'comMicrobial Fuel cell isbio-electrochemicalfuel cell $here the anode reaction is controlled by microorganisms''Anode respiratory bacteria'have the ability to convert bio%$aste to electrons'MediatedMethylene )lue, thionine, or humic acidMediator acts as electrolyteFacilitates e% transfer from microbial cells to the electrodeMediator is necessary because most microbes are electrochemically inactive*t+s ,ust sciencemediator crosses the outer membrane-ccepts e% that $ould normally be ta.en up by /0e% laden mediator exits cell and transports e% to anodeafter e% deposition, mediator returns to original oxidi1ed stateC20300/22 4 2530/ %%%6 20C/0 4 7834 4 78e% #he bio9lm is attached to the anode-naerobic conditions force bacteria to respire anaerobically duh!:' ;hanthini 0< Feb 0=2=Source: http://parts.mit.edu/igem07/images/2/2d/Fuelcell.JPGMicrobial Fuel ells:' ;hanthini 0< Feb 0=2=a!odecathodeMicrobial Fuel ellsSource: http://parts.mit.edu/igem07/images/2/2d/Fuelcell.JPG:' ;hanthini 0< Feb 0=2="! a!ode a!d a cathode are co!!ected b# a! e$ter!al electrical circuit% a!d separated i!ter!all# b# a! io! e$cha!ge membra!e. :' ;hanthini 0< Feb 0=2=Microbes gro&i!g i! the a!odic chamber metaboli'e a carbo! substrate (glucose i! this case) to produce e!erg# a!d h#droge!. :' ;hanthini 0< Feb 0=2=*#droge! ge!erated is reduced i!toh#droge! io!s (proto!) a!d electro!s.

+*,2-+ . 2*2- / 2*0--* . 2-2 . 1*2 or

+*,2-+ / *0*2*2--* . 2-2 . 2*2:' ;hanthini 0< Feb 0=2=2lectro!s are tra!s3erred to the a!odic electrode% a!d the! to the e$ter!al electrical circuit. 4he proto!s mo5e to the cathodic compartme!t 5ia the io! e$cha!ge cha!!el a!d complete the circuit.:' ;hanthini 0< Feb 0=2=4he electro!s a!d proto!s liberated i! the reactio! recombi!e i! the cathode.63 o$#ge! is to be used as a! o$idi'i!g age!t% &ater &ill be 3ormed."! electrical curre!t is 3ormed 3rom the pote!tial di33ere!ce o3 the a!ode a!d cathode% a!d po&er is ge!erated.:' ;hanthini 0< Feb 0=2=4he a!ode a!d cathode electrodes are composed o3 graphite% carbo! paper or carbo! cloth. 4he a!odic chamber is 3illed &ith the carbo! substrate 3or the microbes to metaboli'e to gro& a!d produce e!erg#. 4he p* a!d bu33eri!g properties o3 the a!odic chamber ca! be 5aried to ma$imi'e microbial gro&th% e!erg# productio!% a!d electric pote!tial.:' ;hanthini 0< Feb 0=2=4he a!ode a!d cathode electrodes are composed o3 graphite% carbo! paper or carbo! cloth. 4he cathodic chamber ma# be 3illed &ith air i! &hich case o$#ge! is the o$ida!t.:' ;hanthini 0< Feb 0=2=7aborator# substrates are acetate% glucose% or lactate. 8eal &orld substrates i!clude &aste&ater a!d la!d3ills.Substrate co!ce!tratio!% t#pe% a!d 3eed rate ca! greatl# a33ect the e33icie!c# o3 a cell.:' ;hanthini 0< Feb 0=2=Microbes should be a!aerobic (3erme!tati5e t#pe) because a!odic chamber must be 3ree o3 o$#ge!. Microbes tested are: E. coli Proteus vulgaris Streptococcus lactis Staphylococcus aureus Psuedomonas methanica Lactobacillus plantarium(Ma!# o3 these species are 9!o&! huma! pathoge!s% a!d pose a pote!tial sa3et# ha'ard.):' ;hanthini 0< Feb 0=2=Microbes should be a!aerobic (3erme!tati5e t#pe) because a!odic chamber must be 3ree o3 o$#ge!. Some bacteria% li9eClostridium cellulolyticum% are able to use cellulose as a substrate to produce a! electrical output bet&ee! ,1.0:;