Abstract:Global consumption of protein is projected to double by the middle of the 21st century1. However, protein production is one of the most energy intensive and environmentally damaging parts of the food supply system today. Electromicrobial production technologies that combine renewable electricity and CO2-fixing microbial metabolism could dramatically increase the energy efficiency of commodity chemical production2–5. Here we present a molecular-scale model that sets an upper limit on the performance of any orga… Show more
“…We have extended our theoretical framework for calculating the efficiency of EMP ( Salimijazi et al., 2020 ; Wise et al., 2021 ) to calculate the energy cost of lixiviant production from renewable electricity and CO 2 . Full derivations of the equations presented here can be found in the supplement to our original electromicrobial production efficiency theory article ( Salimijazi et al., 2020 ), and in our recent work on the electromicrobial production of protein with extends our theory to calculate the energy (electrical or solar) costs of producing a gram of product ( Wise et al., 2021 ).…”
Section: Resultsmentioning
confidence: 99%
“…The amount of electricity needed to produce a unit-mass of the lixiviant is, where eν elix is the amount of charge needed to synthesize a single lixiviant molecule from CO 2 (the fundamental charge, e , multiplied by the number of electrons needed for synthesis, ν elix ); Δ U cell is the potential difference across the bio-electrochemical cell; and N A is the Avogadro constant. A derivation of ( Equation 11 ) can be found in Wise et al., 2021 , building upon derivations in Salimijazi et al., 2020 . Figure 2 Schematic of the electromicrobial production of lixiviants for CO 2 mineralization (A) Single bio-electrochemical cell system where electricity is used to power in vivo CO 2 - and subsequent lixiviant synthesis.…”
Section: Resultsmentioning
confidence: 99%
“…For systems where CO 2 reduction is performed electrochemically, and the resulting reduction product (typically a C 1 compound such as formic acid) ( Appel et al., 2013 ; White et al., 2014 , 2015 ) is further reduced enzymatically, ν elix is substituted for the number of electrons needed to convert the C 1 product into the lixiviant, ν elix, add ( Salimijazi et al., 2020 ), where ν r is the number of primary reduction products (i.e., formic acid molecules) needed to synthesize a molecule of the final product, ν er is the number of electrons needed to reduce CO 2 to a primary reduction product (i.e., two in the case of formic acid), ν Cr is the number of carbon atoms per primary fixation product (i.e., one in the case of formic acid), ξ I2 is the Faradaic efficiency of the bio-electrochemical cell, ξ I1 is the Faradaic efficiency of the primary abiotic cell 1, ξ C is the carbon transfer efficiency from cell 1 to cell 2. A derivation of ( Equation 12 ) can be found in Wise et al., 2021 .…”
Section: Resultsmentioning
confidence: 99%
“…Electromicrobial production technologies already have lab-scale efficiencies that can exceed the theoretical upper limit efficiencies of most forms of photosynthesis ( Haas et al., 2018 ; Liu et al., 2016 ; Torella et al., 2015 ), and have even further room to improve ( Salimijazi et al., 2020 ; Wise et al., 2021 ). This means that electromicrobial production might be able to produce lixiviants for CO 2 mineralization from electricity and CO 2 without needing to compete for land with agriculture and wilderness.…”
Section: Resultsmentioning
confidence: 99%
“…EMP technologies ( Claassens et al., 2019 ; Lips et al., 2018 ; Prévoteau et al., 2020 ; Rabaey et al., 2011 ; Rabaey and Rozendal, 2010 ; Salimijazi et al., 2019 ) that combine biological and electronic components have been demonstrated at lab scale to have the energy to chemical conversion efficiencies exceeding all forms of terrestrial photosynthesis ( Haas et al., 2018 ; Liu et al., 2016 ), while theoretical predictions indicate that their efficiency could exceed all forms of photosynthesis ( Claassens et al., 2019 ; Leger et al., 2021 ; Salimijazi et al., 2020 ; Wise et al., 2021 ). Globally, photosynthesis has an average solar to biomass conversion of less than 1% ( Barstow, 2015 ).…”
“…We have extended our theoretical framework for calculating the efficiency of EMP ( Salimijazi et al., 2020 ; Wise et al., 2021 ) to calculate the energy cost of lixiviant production from renewable electricity and CO 2 . Full derivations of the equations presented here can be found in the supplement to our original electromicrobial production efficiency theory article ( Salimijazi et al., 2020 ), and in our recent work on the electromicrobial production of protein with extends our theory to calculate the energy (electrical or solar) costs of producing a gram of product ( Wise et al., 2021 ).…”
Section: Resultsmentioning
confidence: 99%
“…The amount of electricity needed to produce a unit-mass of the lixiviant is, where eν elix is the amount of charge needed to synthesize a single lixiviant molecule from CO 2 (the fundamental charge, e , multiplied by the number of electrons needed for synthesis, ν elix ); Δ U cell is the potential difference across the bio-electrochemical cell; and N A is the Avogadro constant. A derivation of ( Equation 11 ) can be found in Wise et al., 2021 , building upon derivations in Salimijazi et al., 2020 . Figure 2 Schematic of the electromicrobial production of lixiviants for CO 2 mineralization (A) Single bio-electrochemical cell system where electricity is used to power in vivo CO 2 - and subsequent lixiviant synthesis.…”
Section: Resultsmentioning
confidence: 99%
“…For systems where CO 2 reduction is performed electrochemically, and the resulting reduction product (typically a C 1 compound such as formic acid) ( Appel et al., 2013 ; White et al., 2014 , 2015 ) is further reduced enzymatically, ν elix is substituted for the number of electrons needed to convert the C 1 product into the lixiviant, ν elix, add ( Salimijazi et al., 2020 ), where ν r is the number of primary reduction products (i.e., formic acid molecules) needed to synthesize a molecule of the final product, ν er is the number of electrons needed to reduce CO 2 to a primary reduction product (i.e., two in the case of formic acid), ν Cr is the number of carbon atoms per primary fixation product (i.e., one in the case of formic acid), ξ I2 is the Faradaic efficiency of the bio-electrochemical cell, ξ I1 is the Faradaic efficiency of the primary abiotic cell 1, ξ C is the carbon transfer efficiency from cell 1 to cell 2. A derivation of ( Equation 12 ) can be found in Wise et al., 2021 .…”
Section: Resultsmentioning
confidence: 99%
“…Electromicrobial production technologies already have lab-scale efficiencies that can exceed the theoretical upper limit efficiencies of most forms of photosynthesis ( Haas et al., 2018 ; Liu et al., 2016 ; Torella et al., 2015 ), and have even further room to improve ( Salimijazi et al., 2020 ; Wise et al., 2021 ). This means that electromicrobial production might be able to produce lixiviants for CO 2 mineralization from electricity and CO 2 without needing to compete for land with agriculture and wilderness.…”
Section: Resultsmentioning
confidence: 99%
“…EMP technologies ( Claassens et al., 2019 ; Lips et al., 2018 ; Prévoteau et al., 2020 ; Rabaey et al., 2011 ; Rabaey and Rozendal, 2010 ; Salimijazi et al., 2019 ) that combine biological and electronic components have been demonstrated at lab scale to have the energy to chemical conversion efficiencies exceeding all forms of terrestrial photosynthesis ( Haas et al., 2018 ; Liu et al., 2016 ), while theoretical predictions indicate that their efficiency could exceed all forms of photosynthesis ( Claassens et al., 2019 ; Leger et al., 2021 ; Salimijazi et al., 2020 ; Wise et al., 2021 ). Globally, photosynthesis has an average solar to biomass conversion of less than 1% ( Barstow, 2015 ).…”
By the end of the century tens of gigatonnes of CO2 will need to be removed from the atmosphere every year to maintain global temperatures. Natural weathering of ultramafic rocks and subsequent mineralization reactions can convert atmospheric CO2 into ultra-stable carbonates. But, while natural weathering will eventually draw down all excess CO2, this process will need hundreds of thousands of years to do it. The CO2 mineralization process could be accelerated by weathering ultramafic rocks with biodegradable lixiviants like organic acids. But, in this article we show that if these lixiviants are produced from cellulosic biomass, the demand created by CO2 mineralization could monopolize the world's supply of biomass even if CO2 mineralization performance is high. In this article we demonstrate that electromicrobial production technologies that (EMP) combine renewable electricity and microbial metabolism could produce lixiviants for as little as $200 to $400 per tonne at solar electricity prices achievable within the decade. Furthermore, this allows the lixiviants needed to sequester a tonne of CO2 to produced for less than $100, even with modest CO2 mineralization performance.
Microbes which participate in extracellular electron uptake or H2 oxidation have an extraordinary ability to manufacture organic compounds using electricity as the primary source of metabolic energy. So-called electromicrobial production could be of particular value in the efficient production of hydrocarbon blends for use in aviation. Because of exacting standards for fuel energy density and the costs of new aviation infrastructure, liquid hydrocarbon fuels will be necessary for the foreseeable future, precluding direct electrification. Production of hydrocarbons using electrically-powered microbes employing fatty acid synthesis-based production of alkanes could be an efficient means to produce drop-in replacement jet fuels using renewable energy. Here, we calculate the upper limit electrical-to-energy conversion efficiency for a model jet fuel blend containing 85% straight-chain alkanes and 15% terpenoids. When using the Calvin cycle for carbon-fixation, the energy conversion efficiency is 38.4% when using extracellular electron uptake for electron delivery and 40.6% when using H2-oxidation. The efficiency of production of the jet fuel blend can be raised to 44.9% when using the Formolase formate-assimilation pathway and H2-oxidation, and to 50.1% with the Wood-Ljungdahl pathway. The production efficiency can be further raised by swapping the well-known ADO pathway for alkane termination with for the recently discovered MCH pathway. If these systems were were supplied with electricity with a maximally-efficient silicon solar photovoltaic, even the least efficient would exceed the maximum efficiency of all known forms of photosynthesis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
