Biotechnology innovations for renewable energy: direct bioelectricity generation and novel biohydrog

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Biotechnology innovations for renewable energy
direct bioelectricity generation and novel
biohydrogen generation technologies. Bruce
Logan, Penn State University
Engineering Environmental Institute
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Energy is the single most critical challenge
facing humanity - Nobel Laureate Richard Smalley
Energy is the single most critical environmental
challenge facing humanity
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Oil and Fossil Fuels

• Existing (coal, oil shale) and new potential
  energy Carbon-based alternatives (methane
  hydrates, coal to gas) pose continued
  environmental challenges.
• A reduction in CO2 emissions is the main driver
  for renewable (CO2-neutral) energy production.

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Energy Utilization in the USA

• US energy use 97 quad
• US electricity generation 13 quad
• 5 used for WWW 0.6 quad
• Energy needed for H2 for transportation-
• Via electrolysis 12 quad Using new
  biomass process 1.2 quad

97 quad quadrillion BTUs 28,400 terawatt hours
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Energy production Needs to become more diverse
and CO2 neutral

• Solar
• Wind
• Biomass
• Combustion electricity
• Conventional biotechnology ethanol, methane,
  other value products
• Novel biotechnological approaches electricity
  and hydrogen

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Energy can be recovered in many forms via
biotechnological approaches

• Methane
• Value 0.43/kg-CH4
• Elevated temperatures required for bioreactors
• Need very long hydraulic detention times (big
  reactors)
• Hydrogen
• Value 6 /kg, 2.2 heat value of methane
• Produced-low yield from fermentation from sugars
• Produced from any biodegradable organic matter
  using the BEAMR process
• Electricity
• Directly generated using microbial fuel cells

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Renewable Energy Production

• Electricity production using microbial fuel cells
• Overcoming the fermentation barrier
• high-yield H2 production from biomass

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Electricity Production in an Aqueous Cathode
Microbial Fuel Cell
load
e-
e-
Fuel (wastes)
O2
bacteria
H
H2O
Oxidation products (CO2)
Anode
Cathode
Proton Exchange membrane
Source Liu et al., Environ. Sci. Technol., (2004)
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Demonstration of a Microbial Fuel Cell (MFC)
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How do electrons reach the electrode?
Carrier (oxidized)

• Early evidence was that bacteria produced their
  own mediators
• Pseudomonas spp. Produce mediators such as
  pyocyanin (Rabaey et al. 2004)
• Recent data suggests that Shewanella spp. use
  other methods

Carrier (reduced)
Fe (III)
Bacterium
Mediators produced by Pseudomonas spp. have
distinct colors. (Photo provided by Korneel
Rabaey, Ghent University, Belgium 2005).
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New finding bacteria use nano-wires
Electrode
Bacterium
e-
e-
e-

• Other bacteria can transfer electrons directly to
  the electrode
• Geobacter sulfureducens
• Alteromonas sp.
• Shewanella spp.

Yuri Goby (2005). Composition, reactivity and
regulation of extracellular metal-reducing
structures produced by dissimilatory
metal-reducing bacteria. Pres. DOE NABIR
meeting, April 20, 810 am, Warrenton, VA.
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Power densities in laboratory MFCs
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Acetate bacteria (Geobacter metallireducens)
Nafion membrane MFC
Proton exchange membrane (PEM)
Average Power 40 mW/m2 (vs 1 mW/m2 w/salt
bridge)
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Electrode spacing
Flat Plate, continuous flow MFC
Single chamber, continuous flow MFCs (SC MFC)
Source Min Logan, Environ. Sci. Technol. (2004)
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MFC- Air cathode systems

• - Increase power with air-cathode (oxygen does
  not need to be dissolved in water
• Remove proton exchange membrane (PEM)

load
e-
e-
Cathode
Anode
Fuel (wastes)
Oxidant (O2)
H
bacteria
Oxidation products (CO2)
Reduced oxidant (H2O)
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Electricity- Glucose
Power 494 mW/m2 (No PEM)
Power 250 mW/m2 (Nafion membrane)
Source Liu Logan, Environ. Sci. Technol. (2004)
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Reduced Electrode spacing Flow through the
Anode
Power 1540 mW/m2 (glucose)
Source Cheng et al. submitted, Environ. Sci.
Technol. (2005)
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MFC Reactors

• Aqueous-cathode MFCs
• Salt Bridge proton exchange system
• Membrane (Nafion)
• Direct air cathodes MFCs
• Single Chamber system for wastewater
• Flat plate system
• Small batch system for optimizing electricity
  generation

0.25 yr-- 0.3 mW/m2
0.5 yr-- 2 mW/m2
1 yr-- 45 mW/m2
1.5 yr-- 500 mW/m2
Current-- 1500 mW/m2
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A Path to Renewable Energy ProductionEnergy
Recovery from Agricultural wastes-
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A Path to Renewable Energy Production Energy
Recovery from Wastewater-
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Energy content of Wastewaters

• Electricity lost to water and wastewater
  treatment 0.6 quad (5 of all electricity)
• Energy in wastewater 0.5 quad
• 0.1 quad of energy in domestic wastewater
• 0.1 quad in food processing wastewater
• 0.3 quad in animal wastes

Wastewater has 9.3 more energy than treatment
consumes (Toronto WWTP, Shizas Bagley
(2003)
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Potential MFC Power density

• Solar energy 0.1 W/m2 (from 1 W/m2)
• WWTP Current performance of fixed film
  wastewater processes equivalent to a power
  density of 1 W/m2 total surface area
• MFC 1 m2 of top surface area
• Each top-m2 can contain 100 -500 m2 height
• If 6 m tall? 600-3000 m2 0.6-3 kW
• MFC 60 m diameter system1.7-8.5 MW

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Electricity- Domestic Wastewater
P26 mW/m2
P 464 mW/m2
Source Liu et al., Environ. Sci. Technol., (2004)
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Renewable Energy Production

• Electricity production using microbial fuel cells
• Overcoming the fermentation barrier
• high-yield H2 production from biomass

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Current sources for H2 Production
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Observation H2 production results primarily from
sugars

• Biogas
• 60 H2
• 40 CO2

Source Logan, VanGinkel Oh Environ. Sci.
Technol. (2002)
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H2 yields Increase by CO2 removal
H2 Yield increased by 43 with CO2 scrubbing
Source Park, Hyun, Oh, Logan Kim, Environ.
Sci. Technol. (2005)
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Observation Lots of waste products, and not
enough acetic acid (best for H2 production)
H2
Acetic
Biomass
Butyric
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Observation the fermentation barrier
Maximum 12 mol-H2/mol-hexose
C6H12O6 2 H2O ? 4 H2 2 C2H4O2 2 CO2
??????
C6H12O6 ? 2 H2 C4H8O2 2 CO2
How can we recover the remaining 8 to 10 mol/mol?
Maximum of 4 mol/mol (2 mol/mol in practice)
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Overcoming the Fermentation Barrier

• Bio-Electrochemically Assisted Microbial Reactor
  (BEAMR) Process developed with Ion Power, Inc.
  
• Acetate achieve 2.9 mol-H2/mol-acetate (Maximum
  of 4 mol/mol)
• Couple fermentation BEAMR process
• ? 8 to 9 mol-H2/mole glucose
• Not limited to glucose

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Essentials of the BEAMR Process

• Conventional MFC
• Anode potential -300 mV
• Cathode Potential 200 mV (804 mV theory)
• Circuit working voltage -(-300) 200 500 mV
• BEAMR Process No oxygen
• Anode potential -300 mV
• Cathode potential 0 mV
• Needed to make H2 410 mV (theory)
• Circuit (300 mV) augmented with gt110 mV gt410 mV

Anode C2H4O2 2 H2O ? 2 CO2 8 e- 8
H Cathode O2 4 H 4 e- 2 H2O
Anode C2H4O2 2 H2O ? 2 CO2 8 e- 8
H Cathode 8 H 8 e- ? 4 H2
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BEAMR Process
PS
H2
CO2
e-
e-
Anode
Cathode
Bacteria
H
No oxygen Cathode chamber is kept anaerobic
O2
PEM
Source Liu, Grot and Logan, Environ. Sci.
Technol. (2005)
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Potential Needed for Hydrogen Production
Minimum voltage needed is gt0.25 V (0.11 V theory)
Source Liu, Grot and Logan, Environ. Sci.
Technol. (2005)
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Hydrogen Recovery

• 60-78 Coulombic Efficiency (electron recovery)
• gt90 H2 recovery
• Overall
• 2.9 mol-H2/mol-acetate

Source Liu, Grot and Logan, Environ. Sci.
Technol. (2005)
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Observation 1 Industries currently throw away
a valuable resource (land application)
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Observation 2 Other countries are investing in
development and scale-up of hydrogen and
alternative energy processes
Large-scale biohydrogen reactor being tested at
Harbin University, China (Director Prof. Nanqi
Ren)
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CONCLUSIONS

• MFCs represent a biotechnological solution to
  electricity generation
• The BEAMR process can overcome the fermentation
  barrier and result in high yields of hydrogen
  from biomass.
• We must develop these technologies, or we risk
  following rather than leading in alternative
  energy development.

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Acknowledgements
Previous sponsors NSF EPA TSE (CTS
Program) USDA-DOE US Filter
Current research sponsors NSF (BES Program)
2004-2007 USDA (2003-2006)
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Thanks to students and researchers in my
laboratory at Penn State!

• Top row (left to right) Bruce Logan, Charles
  Winslow, Neinke Stein visiting researcher,
  Joshua Middaugh undergrad, Karl Shellenberger,
  Garret Estadt undergrad, David Jones
• Bottom row JungRae Kim, Huilian Ma postdoc.,
  Shaoan Cheng postdoc., Jenna Heilmann
  graduated, Yi Zuo, SangEun Oh postdoc.

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Questions ?
Email blogan_at_psu.edu Web page
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