Development of Electro-Microbial Carbon Capture and Conversion Systems

Handle URI:
http://hdl.handle.net/10754/625040
Title:
Development of Electro-Microbial Carbon Capture and Conversion Systems
Authors:
Al Rowaihi, Israa S. ( 0000-0002-6953-8787 )
Abstract:
Carbon dioxide is a viable resource, if used as a raw material for bioprocessing. It is abundant and can be collected as a byproduct from industrial processes. Globally, photosynthetic organisms utilize around 6’000 TW (terawatt) of solar energy to fix ca. 800 Gt (gigaton) of CO2 in the planets largest carbon-capture process. Photosynthesis combines light harvesting, charge separation, catalytic water splitting, generation of reduction equivalents (NADH), energy (ATP) production and CO2 fixation into one highly interconnected and regulated process. While this simplicity makes photosynthetic production of commodity interesting, yet photosynthesis suffers from low energy efficiency, which translates in an extensive footprint for solar biofuels production conditions that store < 2% of solar energy. Electron transfer processes form the core of photosynthesis. At moderate light intensity, the electron transport chains reach maximum transfer rates and only work when photons are at appropriate wavelengths, rendering the process susceptible to oxidative damage, which leads to photo-inhibition and loss of efficiency. Based on our fundamental analysis of the specialized tasks in photosynthesis, we aimed to optimize the efficiency of these processes separately, then combine them in an artificial photosynthesis (AP) process that surpasses the low efficiency of natural photosynthesis. Therefore, by combining photovoltaic light harvesting with electrolytic water splitting or CO2 reduction in combination with microbiological conversion of electrochemical products to higher valuable compounds, we developed an electro-microbial carbon capture and conversion setups that capture CO2 into the targeted bioplastic; polyhydroxybutyrate (PHB). Based on the type of the electrochemical products, and the microorganism that either (i) convert products formed by electrochemical reduction of CO2, e.g. formate (using inorganic cathodes), or (ii) use electrochemically produced H2 to reduce CO2 into higher compounds (autotrophy), three AP setups were designed: one-pot, two-pot, and three-pot setups. We evaluated the kinetic (microbial uptake and conversion, electrochemical reduction) and thermodynamics (efficiencies) of the separate processes, and the overall process efficiency of AP compared to photosynthesis. We address the influence of several parameters on efficiencies and time-space yields, e.g. salinity, pH, electrodes, media, partial pressures of H2 and CO2. These data provide a valuable basis to establish a highly efficient and continuous AP process in the future.
Advisors:
Eppinger, Jorg ( 0000-0001-7886-7059 )
Committee Member:
Tester, Mark A. ( 0000-0002-5085-8801 ) ; Takanabe, Kazuhiro ( 0000-0001-5374-9451 ) ; Banat, Ibrahim M.
KAUST Department:
Biological and Environmental Sciences and Engineering (BESE) Division
Program:
Bioscience
Issue Date:
May-2017
Type:
Dissertation
Appears in Collections:
Dissertations

Full metadata record

DC FieldValue Language
dc.contributor.advisorEppinger, Jorgen
dc.contributor.authorAl Rowaihi, Israa S.en
dc.date.accessioned2017-06-15T11:22:56Z-
dc.date.available2017-06-15T11:22:56Z-
dc.date.issued2017-05-
dc.identifier.urihttp://hdl.handle.net/10754/625040-
dc.description.abstractCarbon dioxide is a viable resource, if used as a raw material for bioprocessing. It is abundant and can be collected as a byproduct from industrial processes. Globally, photosynthetic organisms utilize around 6’000 TW (terawatt) of solar energy to fix ca. 800 Gt (gigaton) of CO2 in the planets largest carbon-capture process. Photosynthesis combines light harvesting, charge separation, catalytic water splitting, generation of reduction equivalents (NADH), energy (ATP) production and CO2 fixation into one highly interconnected and regulated process. While this simplicity makes photosynthetic production of commodity interesting, yet photosynthesis suffers from low energy efficiency, which translates in an extensive footprint for solar biofuels production conditions that store < 2% of solar energy. Electron transfer processes form the core of photosynthesis. At moderate light intensity, the electron transport chains reach maximum transfer rates and only work when photons are at appropriate wavelengths, rendering the process susceptible to oxidative damage, which leads to photo-inhibition and loss of efficiency. Based on our fundamental analysis of the specialized tasks in photosynthesis, we aimed to optimize the efficiency of these processes separately, then combine them in an artificial photosynthesis (AP) process that surpasses the low efficiency of natural photosynthesis. Therefore, by combining photovoltaic light harvesting with electrolytic water splitting or CO2 reduction in combination with microbiological conversion of electrochemical products to higher valuable compounds, we developed an electro-microbial carbon capture and conversion setups that capture CO2 into the targeted bioplastic; polyhydroxybutyrate (PHB). Based on the type of the electrochemical products, and the microorganism that either (i) convert products formed by electrochemical reduction of CO2, e.g. formate (using inorganic cathodes), or (ii) use electrochemically produced H2 to reduce CO2 into higher compounds (autotrophy), three AP setups were designed: one-pot, two-pot, and three-pot setups. We evaluated the kinetic (microbial uptake and conversion, electrochemical reduction) and thermodynamics (efficiencies) of the separate processes, and the overall process efficiency of AP compared to photosynthesis. We address the influence of several parameters on efficiencies and time-space yields, e.g. salinity, pH, electrodes, media, partial pressures of H2 and CO2. These data provide a valuable basis to establish a highly efficient and continuous AP process in the future.en
dc.language.isoenen
dc.subjectArtificial Photosynthesisen
dc.subjectElectrolysisen
dc.subjectCarbon capture Electro-microbialen
dc.subjectPolyhydroxyalkanoate (PHB)en
dc.subjectBioprocessingen
dc.titleDevelopment of Electro-Microbial Carbon Capture and Conversion Systemsen
dc.typeDissertationen
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Divisionen
thesis.degree.grantorKing Abdullah University of Science and Technologyen_GB
dc.contributor.committeememberTester, Mark A.en
dc.contributor.committeememberTakanabe, Kazuhiroen
dc.contributor.committeememberBanat, Ibrahim M.en
thesis.degree.disciplineBioscienceen
thesis.degree.nameDoctor of Philosophyen
dc.person.id123816en
All Items in KAUST are protected by copyright, with all rights reserved, unless otherwise indicated.