| NSF Org: |
TI Translational Impacts |
| Recipient: |
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| Initial Amendment Date: | November 13, 2013 |
| Latest Amendment Date: | November 13, 2013 |
| Award Number: | 1346424 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Prakash Balan
pbalan@nsf.gov (703)292-5341 TI Translational Impacts TIP Directorate for Technology, Innovation, and Partnerships |
| Start Date: | January 1, 2014 |
| End Date: | December 31, 2014 (Estimated) |
| Total Intended Award Amount: | $225,000.00 |
| Total Awarded Amount to Date: | $225,000.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
15 Reads Way New Castle DE US 19720-1600 (302)220-4760 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
150 S College Ave Newark DE US 19716-7200 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | STTR Phase I |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.084 |
ABSTRACT
This Small Business Technology Transfer Research Phase I project aims to enhance fermentation yield of four carbon (C4) chemicals by instating mixotrophic fermentation. In order to realize the most cost effective fermentation for commodity chemical and biofuel production, the process should achieve maximum conversion of feedstock. In carbohydrate fermentations, CO2 and H2 are commonly evolved, which negatively impacts yield of desired products. We hypothesize that mixotrophic fermentation can recapture that yield loss. We define mixotrophic fermentation as the simultaneous consumption of organic and inorganic substrates. Improvements in yield from mixotrophic fermentation can be very significant. Moreover, certain clostridial organisms in theory can perform such fermentation, but relatively little is known about this. Moreover, the genetic tools to manipulate these microorganisms are underdeveloped. Consequently, this Phase I STTR will develop a genetic toolbox for these microorganisms, interrogate their ability for simultaneous substrate utilization of both carbohydrate and gas, and demonstrate the potential to produce C4 chemicals from mixotrophic fermentation.
The broader impact/commercial potential of this project is to develop renewable and domestic chemical production and transportation fuel technologies that are cheaper, greener and more sustainable. Project outcomes, have the potential to increase product yield 10 ? 50%, which greatly reduces production-operating expense. The potential to utilize CO2 in the fermentation, minimizes the carbon footprint of the process. Lastly, process sustainability is enhanced since a greater diversity of feedstocks can be concurrently used such as complex carbohydrates, five and six carbon sugar monomers, biodiesel waste, hydrolyzed biomass, syngas, waste gas, and activated methane molecules. Overall, the project has the commercial potential to improve the triple bottom line of many chemical companies. Furthermore, this project could significantly enhance scientific and technological understanding of microbial physiology and metabolism during gas and carbohydrate fermentation.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
It is of major importance to the United States to develop renewable and domestic chemical production and transportation fuel technologies. Additionally, chemical companies are constantly looking for ways to improve business sustainability by reducing carbon footprints along with cost of manufacturing. Mixotrophic fermentation can be a step-change improvement in microbial fermentation for the production of numerous intermediate and commodity chemicals. By mixotrophic fermentation, we mean the simultaneous consumption of both a carbohydrate (sugar) and a gaseous substrate, where the gaseous substrate can be evolved from the sugar fermentation itself and/or be provided exogenously. By utilizing both sugar and gases as feedstock, mass yields of products can be increased 10 – 100% over yields from sugar alone, and all CO2 gas from the entire process can be captured and assimilated into valuable chemicals, which translates into a 10 – 50% reduction in operating expenses for any commodity or intermediate chemical production process. Consequently, the commercial and environmental implications are tremendous.
The form of mixotrophy described above can theoretically be performed by acetogenic bacteria that have both a sugar utilization pathway, namely glycolysis, and a gas utilization pathway, namely the Wood-Ljungdahl pathway (WLP). For greater detail, we recommend reviewers read our invited review in Current Opinion in Biotechnology[1]. A major question that has yet to be answered in the literature, is if both of these pathways can simultaneously function at considerable rates, or if there are carbon catabolite repression (CCR) elements that prevent both pathways from operating in tandem? As a result of our Phase I research, we clearly demonstrated that mixotrophic fermentation is occurring natively in several acetogenic bacteria.
In addition, we demonstrated the ability to metabolically engineer these acetogenic bacteria by introducing desired elements of butanoate metabolism to produce non-native C3 and C4 chemicals. When these engineered strains were grown under mixotrophic conditions, products of interest were produced at mass yields 40% greater than what is theoretically possible on sugar alone. This provides a more efficient use of the sugar feedstock and as a direct result provides a significant economic advantage to mixotrophic fermentation and has drawn considerable interest in the industry and literature.
[1] Fast, AG, Schmidt, ED, Jones, SW, & Tracy, BP. 2014. “Aetogenic mixotrophy: novel options for yield improvement in biofuels and biochemical production.” Curr Opin Biotechnol doi: 10.1016/j.copbio.2014.11.014.
Last Modified: 02/02/2015
Modified by: Bryan P Tracy
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