This is for Erika to check out, tell me what you think!!!

1. Microbial Fuel Cell based on Exoelectrogenic Bacteria-Electrode Interface MEMS 2009 26 January 2009 Erika Parra UC Berkeley

2. Nature’s Solution: Organic Power 100W 850 W Prokaryote Up to 5 W/mL 15min 42km

3. Applications : Artificial Metabolism Honda’s Asimo MEMS  Robots Hollar, Pister (2001) Portable Remote sensors 2.5 mm Solar cell

5. Previous Work: Thylakoid Photo Fuel Cell Problem: Very low efficiency due to diffussion of electron transfer process Lam, Johnson and Lin, JMEMS, pp. 1243-1250, 2006 Electrodes V CATHODE Plant Thylakoids ANODE PMS e - e - e - e - e - e - H + H + H + H + H + PMS Fe(III) Fe(II) e -

6. Microbiology: Exoelectrogenic Bacteria Organic nanowire Geobacter sulfurreducens Extracellular Acceptors Intracellular Acceptors Cytoplasm Periplasm Extracellular e- Cytochromes NADH NAD+ Med Ox Med Red

7. Biofilm: Protein Nanowires Multiple and connected 5nm x 10  m Biofilms < 50  m Reguera and Lovley, Nature 435 , 1098-1101, 2005

8. Device: Fuel Cell O 2 H 2 O Anode Cathode PEM Bacterial biofilm Respiring on electrode H + e-

15. Future Work: MEMS for MFCs Potential System Energy Density Au Nanowire transport Biofilm connectivity Real-time activity Moving target 6.1 6.8 8.0 MJ/L Usable 60 1.9 15.3 Acetate in MFC 20 34.2 Gasoline Device Bacteria Δ H c º (HHV) 60 % Eff. 10.1 Hydrogen (liquid) MJ/L MJ/L

16. Conclusions… Biomimetic and Sustainable Approach to Energy Conversion Performance (first demonstration) V oc ≈ 600mV (1 V vs. O 2 ) I max ≈ 1.5 µA/mm 2 P max ≈ 0.1 µW/mm 2 Need higher resolution and real-time monitoring

17. Special Thanks… Team and Collaborators Supporters SPS Program IEEE Prof. Lin, Erika Parra, and Ryan Yang Mechanical Engineering Prof. Coates and Kelly Wrighton Plant and Microbial Biology Prof. Yang Chemistry