wi with th MFC FC Winnie Christ Ziyan Phoebe Energy crisis - - PowerPoint PPT Presentation

Mor

• re Fres

esh h wa water er & & Clea ean n en ener ergy gy

wi with th MFC FC

Electr ctricit icity Col

• li Enables

South China Agricultural University, Canton, China

Christ Ziyan Winnie Phoebe

Energy resources

New energy  Clean  Renewable  Low-cost

Energy crisis

Non-renewable Pollutant

Ice layer

3% Fresh water

The “water planet” is short of fresh water

97% Sea water

Oceans

water

70% Earth surface

0.007% Used directly

Sea water

+ + + +

• Anode

Cathode

Sea water desalination based on Electrodialysis

Problem: High energy consumption

H2O

H+

e-

PEM

Anode Chamber Cathode Chamber Anode Chamber Cathode Chamber

PEM

Anode Chamber Cathode Chamber

O2

PEM

Anode Chamber Cathode Chamber

+

• +
• +

+ -

• +

+

AEM CEM

e-

Introduction of MFC and MDC

Microbial Desalination Cells Microbial Fuel Cells

MDCs = MFCs + disalination chamber Fresh water

PEM: proton exchange membrane AEM: anion exchange membrane; CEM: cation exchange membrane

Low power output restrains the wide usage of MFC/MDC!

Des esigns ns and nd Re Results lts

• f
• f ou
• ur pr

r proj

• ject

ect

NaAD

e-

NAD+ NADH

NAD synthetase

(Electron carrier)

Production of electron carrier NADH in cells

TCA

NADH

Aerobic

ArcA

ArcA

Pi

Anaerobic TCA

NADH

• P

ArcB

Two strategies to increase NADH in our project

NAD+

NaAD

nadE NADH

e-

NAD+ NAD+ NAD+ NADH NADH NADH

e- e-e-

NAD synthetase Over-expression Strong TCA NADH

ArcA

Pi

ArcA-P

Anaerobic (in MFC/MDC) TCA NADH

ArcA-P Knock-out

e- e-

ArcB

arcA gene is knocked-out by λ-Red recombination

Construct for nadE over-expression

875 bp 2953 bp 2755 bp 897 bp 2068 bp Xba I - Spe I

The nadE is over-expressed driven by different promoters

W: Weak Promoter mRNA level S: Strong Promoter W S W S Protein level

Anode chamber Cathode chamber

Our MFC device

Proton exchange membrane (PEM)

The arcA knock-out strain produces more electric change

The nadE over-expression strain produces higher voltage

R =10 kΩ

Genetically modified strains produce more electric charge

R =10 kΩ

Weak Strong

Microbial Desalination Cells

Comparison of electrodialysis and MDCs

Electrodialysis

+ + + +

• Fresh

water

PEM

Anode Chamber Cathode Chamber

• +
• +
• +

+ +

• AEM

CEM

e-

Fresh water

Desalination Chamber

AEM CEM

Our MDCs device

C D

Flow of dilute (D) and concentrate (C) water in MDCs

Four-chamber air-cathode MDCs

Diluant effluent Concentrate effluent Anode chamber Cathode chamber Desalination chamber

Schematic design of stacks in MDCs

C D

Promising desalination rate is achieved in our MDCs

Con

• nclusio

clusion

Electri ctricit city Coli li

 Eight biobricks were submitted to iGEM database  Genetic modification of microbes is a promising way to improve electricity yield  Our MFC-based MDC system is able to turn seawater to fresh water

TCA NADH

Fut uture ure di direction ection

 If organic wastewater can be used as energy source by microbes in MFC/MDC, our project will further benefit the environment.  If the arcA is controlled by an inducible promoter, the ΔarcA mutant would be rescued under low nutrient condition.

TCA NADH

ArcA-P Knock-out

Inducer

Inducible Promoter

Carbon Starvation

ArcA-P

Human Practice

Exhibition

Teach-In

Internet Public Platform Expert Interview

Online Survey Visiting Meet-up

• Exhibition Broad
• Microscope Area
• Photo Model
• Signature wall

Scientific Exhibition in Guangdong Science Center

Exhibition

High School Teach-In

Teach-In

• Lectures
• Discussions on synthetic biology

Internet Public Platform Internet Public Platform

• MFCs/ MDCs research status
• Bi-Language (Chinese and English)
• Public Awareness

Expert Interview

Online Survey

• Ideas and Thoughts exchanging
• Talks with desalination companies

Visiting Meet-up

All the way down to Boston…… Guangzhou Beijing San Francisco Boston

Te Team Members bers

Te Team Members bers Dry Lab

Acknowledgements

• Prof. Chen
• Prof. Deng
• Prof. Wen
• Dr. Hu
• Prof. Hao

Thank you for attention !