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Page 27

Volume 2

Journal of Microbiology and Biotechnology Reports

Microbial Biotechnology 2018

September 17-18, 2018

Microbial Biotechnology & Vaccine Design

September 17-18, 2018 Lisbon, Portugal

5

th

World Congress on

Recycling waste CO

2

to valuable resources through microbial electrosynthesis

Pascal E Saikaly, Krishna P Katuri, Manal F Alqahtani, Bin Bian and Zhiping Lai

King Abdullah University of Science and Technology, Saudi Arabia

Anthropogenic and industrial activities have led to a rapid rise in the atmospheric CO

2

concentrations leading to increased

global warming. A new approach that has emerged in recent years is that of Microbial Electrosynthesis (MES), which relies on

chemolithoautotrophic bacteria that can uptake electrons directly or indirectly (via H2) from the cathode of an electrochemical

cell to catalyze the reduction of CO

2

into fuels or value-added chemicals. Gas-liquid mass transfer is one of the limiting factors in

MES, mainly because of the low solubility of gaseous CO

2

in solution. To overcome this limitation, we developed dual-function

electro-Catalytic and macro Porous Hollow-Fiber (CCPHF) cathodes that act as an electron donor for chemolithoautotrophs as

well as a diffusive material to facilitate direct delivery of CO

2

gas to chemolithoautotrophs through the pores in the hollow fibers.

Using the CCPHF cathode we observed a Faradic efficiency of 77% for the production of CH

4

from CO

2

through hydrogenotrophic

methanogens when CO

2

was delivered directly through the pores of the CCPHF cathode, compared to 3% when gaseous CO

2

was

bubbled into the solution. We also successfully demonstrated that the rates of product formation can be enhanced by using Carbon

Nanotubes (CNTs), which increases CO

2

adsorption capability and enhances microbe-electrode interactions. Modification of the

CCPHF cathodes with CNTs resulted in 70% increase in acetate production rate from CO

2

in MES using the homo acetogenic

bacterium Sporomusa ovata. The use of CCPHF cathodes in MES research is a significant breakthrough. The high specific surface

area of the CCPHF cathode maximizes the diffusion of CO

2

gas, and the high surface-area-to-volume ratio of the CCPHF cathode

architecture solves the issue of cathode packing density for large-scale applications. Most importantly, using CCPHF cathodes make

the MES process highly attractive for on-site carbon capture and utilization.

Biography

Pascal E Saikaly has received his Bachelors in Biology and Masters in Environmental Technology from the American University of Beirut, Lebanon. He has

completed his PhD in Environmental Engineering from the University of Cincinnati and pursued his training as a Post-doctorate at North Carolina State University.

He is currently working as an Associate Professor at King Abdullah University of Science and Technology. His research interests include microbial electrochemical

systems, membrane bioreactors, electro-microbiology and advanced materials for water and energy applications. He has more than 74 refereed journal articles.

pascal.saikaly@kaust.edu.sa

Pascal E Saikaly et al., J Microbio and Biotech Rept 2018, Volume 2