Electrobiome®: Microbial Production of Chemicals & Fuels from CO¬2


The inventors have developed an electrosynthetic microbiome, called the Electrobiome®, which converts CO2, water, and electricity into hydrogen (H2), formic acid, and acetic acid.  The Electrobiome® has been continually operating for more than four years and can operate with intermittent power, which demonstrates sustainability that far surpasses other electrosynthetic microbiomes.  Recent improvements to the Electrobiome® have led to a large leap in productivity.  For example, the new Electrobiome® platform can produce .78 g/L/hour, with indications that >2 g/L/hour and >30% energy efficiency are feasible.  In comparison, rates of 1.25 to 3.75 g/L/hour are achieved by the fermentation of sugar to bioethanol.  However, bioethanol production requires large amounts of arable land, petroleum, and several months of plant growth to generate sugar feedstock.  Microbial electrosynthesis with the Electrobiome® requires none of these.  The present system can also be used to produce acetic acid to then feed other microbes to synthesize fuels and chemicals, such as coupling the Electrobiome® producing acetic acid with heterotrophic algae that non-photosynthetically produce omega-3 fatty acids for human nutraceuticals, aquaculture, pet food, or as feedstock for the production of polyols and polyurethane.  Algae fed electrosynthetic acetic acid may also be used to produce starch, protein, and/or liquid hydrocarbon fuel; the latter generated by hydrothermal liquefaction or consolidated algal processing.

Overview: Markets for the Electrobiome® carbon-neutral products are sizeable and growing (annual global: H2 $118B in 2016, fatty acids to $13B by 2017) and the operation of the Electrobiome® is within range of cost competitiveness.  For example, with 35% energy efficiency it has produced 2 kg acetate plus 3 kg of H2 per m3catholyte per day from 350 kWh or $7 of electricity ($0.02 per kWh, the price of wind power in some US locations enabled with PTC/ITC/Treasury Grant).  This is $1 of acetate (bulk price $50 to $100 per metric ton as of 4/18/16) leaving $6 of electricity to produce 3 kg of H2 ($2/kg excluding pressurization and distribution – a US DOE target).  The H2 may be used directly as a stationary or transportation fuel, or for further chemical upgrades. 

Formic and acetic acids are used as food additives and preservatives, and to produce adhesives, plastics, paints, and dyes.  Considering using the acetic acid as algal feedstock: gasoline, diesel, or jet fuel may be produced by hydrothermal liquefaction of the algae for a minimum-selling price of $4.77 per gallon (~$1.60 per kg).  Since the at-pump price for fuel in the U.S. is approximately half of that, there is a growing interest in harvesting multiple products from algae, such as omega-3s which sell for >$100 per kg.  Growing algae with light requires large land areas or expensive photobioreactors due to low photosynthetic efficiency (1.2 to 2.7% of sunlight captured), whereas modern solar panels capture ~20% of sunlight.  Using solar electricity with the Electrobiome® would be far more efficient, and the Electrobiome® feeding heterotrophic algae could operate entirely without sunlight when using wind, nuclear, tidal, hydro, or geothermal power source.  Additionally, the Electrobiome® can be used to store stranded power in valuable chemicals and fuels, thereby valorizing lost electricity and CO2.


Advantages: Sustainable production of fuels, chemicals, and nutraceuticals from waste CO2 and renewable electricity with potential to lower raw material cost, reduce carbon footprint, and store stranded power in higher value products and liquid fuels.


Key Words: Electrosynthesis, Renewable fuels, Hydrogen, Acetic Acid, Omega-3s, CO2 utilization


Publications: LaBelle, Edward V., et al. “Energy efficiency and productivity enhancement of microbial electrosynthesis of acetate.”  Frontiers in Microbiology (2017), 8(756): 1-9.


May, Harold D., et al. “The bioelectrosynthesis of acetate.” Current Opinion in Biotechnology (2016), 42:225–233.


Ross, Daniel E., et al. “Comparative genomic analysis of Sulfurospirillum cavolei MES reconstructed from the metagenome of an electrosynthetic microbiome.” PloS ONE (2016), 11(3): e0151214.


Ross, Daniel E., et al. “Draft Genome Sequence of Sulfurospirillum sp. Strain MES, Reconstructed from the Metagenome of a Microbial Electrosynthesis System.” Genome Announcement (2015), vol 3., no. 1 e01336-14.


LaBelle, Edward V., et al. “Influence of acidic pH on hydrogen and acetate production by an electrosynthetic microbiome.” PloS ONE (2014), 9(10): e10993. 


Marshall, Christopher W., et al. "Long-term Operation of Microbial Electrosynthesis Systems Improves Acetate Production by Autotrophic Microbiomes. Environmental science & Technology (2013), 2013, 47:6023-6029.   


Marshall, Christopher W., et al. "Electrosynthesis of commodity chemicals by an autotrophic microbial community."  Applied and environmental microbiology78.23 (2012): 8412-8420.


Inventors:  H.D. May, E.V. LaBelle, C.W. Marshall

Patent Status: US 9879251, WO2018102070A2

MUSC-FRD Technology ID: P1305 and P1718


Patent Information:
For Information, Contact:
MUSC Foundation for Research Development
Harold May
Edward LaBelle
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