department of

physics and astronomy

Microbe Power What can bacteria teach us about Energy,

the Environment, and Nanotechnology?

Moh El-Naggar

Physics and Astronomy, University of Southern California

Physics Instant Update: Workshop for High School Physics Teachers 06/24/2009

department of

physics and astronomy

A Los Angeles/SC High School Bioenergy Challenge?

•! Microbial Fuel Cells can be assembled with simple, inexpensive components. Can be built for high schools at USC.

•! Testing can be done with simple voltmeters

•! Proposing an annual workshop to train a teacher and ‘star’ student from each high school in building fuel cells.

•! Schools come back and compete a year later!

Interested? Contact me: mnaggar@usc.edu

department of

physics and astronomy

A resource for teaching Biophysics

http://www.bionumbers.org

department of

physics and astronomy

How it all started

Antony van Leeuwenhoek (1632-1723)

“For me, this was among all the marvels

that I discovered in nature the most

marvelous of all, and I must say, that for my

part, no more pleasant sight has met my eye

than this of so many thousand living

creatures in one small drop of water.”

http://www.ucmp.berkeley.edu/history/leeuwenhoek.html

department of

physics and astronomy

Bioenergy Environmental

Cleanup Uranium(VI)

Uranium(IV)

Nanotechnology

semiconductive nanotubes

magnetic nanoparticles

Lovley et al.1991. Nature 350:413-416.

Gorby et al. 1992 Environ. Sci.

Technol. 26:205-207.

Gorby et al, PNAS 103, 11358-11363 (2006)"

Ji-Hoon Lee et al. PNAS 104 20410-2041 (2007)

http://mfc-muri.usc.edu

Look what bacteria can do for us

department of

physics and astronomy

How they do it: Working with Electrons

Electron Donor "

(for food)"

Electron Acceptor "

(for breathing)"

•! e- flow along the cell membrane, through a series of carriers

•! H+ translocated across the membrane, charging a bio capacitor

•! Capacitor used to drive the synthesis of biologically useful energy i.e. ATP

department of

physics and astronomy

Shewanella oneidensis MR-1"Myers & Nealson, Science 240: 1319-1321, 1988"

e- donors!

Formate"

Lactate"

Pyruvate"

Amino Acids"

H2"

e- acceptors!

O2"

NO3-, NO2

-"

Mn(IV)"Mn(III)"Fe(III)"

Fumarate"DMSO"

S2O32-"

U(VI)"Cr(VI), Tc, As...."

S. oneidensis MR-1 growing on Fe2O3 (Pacific Northwest National Lab)"

•! Isolated in 1987

•! Very versatile: many donors & acceptors

•! Can “breathe solids”

How they do it: Metabolic Versatility

department of

physics and astronomy

Breathing Manganese – take 1

Howard Harris (USC)

department of

physics and astronomy

Breathing Manganese- take 2

Howard Harris (USC)

department of

physics and astronomy

Why this is remarkable: Extracellular Electron Transfer

•! Dissolved electron acceptors are accessible to intracellular machinery

•! But what about solids?

•! Opens up many possibilities: e.g. Bioenergy in Microbial Fuel Cells

Heidelberg et al, Nature Biotech. 20, 1118-1123, 2002"

MtrB 1776

MtrA 1777

MtrC 1778 OmcA 1779

…..

department of

physics and astronomy

How MFCs Work

•! Key feature here is ability to transfer electrons directly to anode"

•! Wide range of power densities reported: 16 - 4300 mW/m2"

•! Low power, but can live off any fuels in the natural environment!"

Anode (e.g. Shewanella w/ Lactate)"

Lactate- + 2H2O Acetate- + HCO3- + 5H+ + 4e-"

Cathode"

O2 + 4H+ + 4e- 2H2O"

department of

physics and astronomy

Microbial Fuel Cells

Bioengineered Fuel Cells: Optimization via Genetic Approaches and Multi-Scale Modeling"http://mfc-muri.usc.edu"

Nealson Lab (USC) Prakash Lab (USC)

department of

physics and astronomy

Bacterial Nanowires: A mechanism for direct

extracellular electron transport

Tapping mode AFM of S. oneidensis

MR-1 with bacterial nanowires and

membrane vesicles

Reductive transformation of hydrous

ferric oxide to Fe3O4 associated with

bacterial nanowires

Gorby et al, PNAS 103, 11358-11363 (2006)"Y.A. Gorby, J. McLean, A. Korenevsky, K. Rosso, M.Y. El-Naggar, and T.J. Beveridge. Geobiology 6, 232-241 (2008)

department of

physics and astronomy

Scanning Tunneling Microscopy

STM confirms the electrical conductivity of the bionanowires

How STM works Bacterial

Nanowire

Gorby et al, PNAS 103, 11358-11363 (2006)"

http://www.nisenet.org/ (Nanoscale Informal Science Education)

department of

physics and astronomy

department of

physics and astronomy

What are they made of?

Deleting the genes responsible for certain proteins (electron transfer proteins)

results in non-conductive appendages

Gorby et al, PNAS 103, 11358-11363 (2006)"

department of

physics and astronomy

Interfacing Biology and Nanotechnology

Measuring individual bacterial nanowires from Shewanella

department of

physics and astronomy

Implications for microbial fuel cells

MFC anode before biofilm After biofilm formation and MFC

operation with Shewanella

Pacific Northwest National Lab

department of

physics and astronomy

Microbe Power

Feeding

Feeding

department of

physics and astronomy

What if it worked?

You think it’s easy running corporate R&D? It

was just fine, as long as the guy didn’t have

anything….The goddamn thing is just a germ

in a box! ……We can’t get into the face of our

fuel suppliers, telling them that we’re replacing

them with sugar water! We own our fuel

suppliers! It’d be like sawing off our own foot!

NATURE |Vol. 441| 18 May 2006

From Distraction, a science-fiction novel by

Bruce Sterling

department of

physics and astronomy

Thank you!