CO2fixation by anaerobic non-photosynthetic mixotrophy for improved carbon conversion.
Maximizing the conversion of biogenic carbon feedstocks into chemicals and fuels is essential for fermentation processes as feedstock costs and processing is commonly the greatest operating expense. Unfortunately, for most fermentations, over one-third of sugar carbon is lost to CO2due to the decarboxylation of pyruvate to acetyl-CoA and limitations in the reducing power of the bio-feedstock. Here we show that anaerobic, non-photosynthetic mixotrophy, defined as the concurrent utilization of organic (for example, sugars) and inorganic (for example, CO2) substrates in a single organism, can overcome these constraints to increase product yields and reduce overall CO2emissions. As a proof-of-concept, Clostridium ljungdahlii was engineered to produce acetone and achieved a mass yield 138% of the previous theoretical maximum using a high cell density continuous fermentation process. In addition, when enough reductant (that is, H2) is provided, the fermentation emits no CO2. Finally, we show that mixotrophy is a general trait among acetogens.
White Dog Labs, Inc., 15 Reads Way, New Castle, Delaware 19720, USA.
Shawn W
SW
Jones
Department of Chemical and Biomolecular Engineering and the Delaware Biotechnology Institute, University of Delaware, 15 Innovation Way, Newark, Delaware 19711, USA.
Alan G
AG
Fast
Department of Chemical and Biomolecular Engineering and the Delaware Biotechnology Institute, University of Delaware, 15 Innovation Way, Newark, Delaware 19711, USA.
Ellinor D
ED
Carlson
White Dog Labs, Inc., 15 Reads Way, New Castle, Delaware 19720, USA.
Carrissa A
CA
Wiedel
Department of Chemical and Biomolecular Engineering and Metabolic Engineering and Systems Biology Laboratory, University of Delaware, 150 Academy Street, Newark, Delaware 19716, USA.
Jennifer
J
Au
Department of Chemical and Biomolecular Engineering and Metabolic Engineering and Systems Biology Laboratory, University of Delaware, 150 Academy Street, Newark, Delaware 19716, USA.
Maciek R
MR
Antoniewicz
Department of Chemical and Biomolecular Engineering and the Delaware Biotechnology Institute, University of Delaware, 15 Innovation Way, Newark, Delaware 19711, USA.
Eleftherios T
ET
Papoutsakis
White Dog Labs, Inc., 15 Reads Way, New Castle, Delaware 19720, USA.
Bryan P
BP
Tracy
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