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The Science and Engineering for a Biobased Industry and Economy
S.E. Nokes, C. Lee, C. Crofcheck, M. Montross
Department of Biosystems and Agricultural Engineering
The Land Grant University System, Resource Limitation, and the Impending Biological Revolution. A need for biofuels and other biobased products has been recognized as a national priority. The objectives of this project address research relating directly to SAAESD Goal 1 F (biobased products) and H (processing agricultural coproducts); research will influence Goal 5 B (rural community development and revitalizing rural economies) indirectly.
The importance and extent of the problem is characterized by the fact that the U.S. must drastically reduce its dependence on petroleum. This is not the fetish of a small proportion of the population; the U.S. society as a whole recognizes the need to reduce its dependence on petroleum as a source of fuels, chemicals and other materials. If this research work is not conducted, the technical capability necessary to switch from a petroleum-based economy to a bioresource-based one will not be developed.
The technical feasibility of the research is reinforced by the fact that this research will be conducted by professional researchers who currently are part of the Land Grant University system. As outlined in this project description, the Land Grant University system provides a unique capability to enable research for biobased products by providing a world class research network. Replacing petroleum products with those originating from biological sources will require significant fundamental and applied research efforts.
Outcomes or projected Impacts: -The committee has served and will continue to serve as a resource for: Bioresearch and Development Initiative (BRDI), Biomass, Research and Development Board working groups, SBIR panel Biofuels 8.8, USDA/DOE Biomass Initiative Project Review Teams, NRI 71.2 panel and reviewers for the Sun Grant Initiative. -The multi-state membership will contribute to the implementation of the REE energy science strategic plan. -Multi-state membership will contribute to identification of funding priorities and shaping policy of Federal agencies -Research as a result of this project will create technology adopted by industry with at least two licensed technology per year. -Research will enable reduced dependency on foreign-based fuels and chemicals.
2010 Project Description
We have found a promising strain of Scenedesmus, which has a high growth rate at a pH less than 7. Chlorella vulgaris and Scenedesmus have been tested with varying amounts of sulfuric acid. Small amounts (6 ppm) appear to have little effect on the culture growth. Intermediate amounts (60 ppm) inhibit growth, but the algae appear to have the ability to recover. Higher amounts (90 ppm) will kill the culture. The influence of strain selection and media components are also currently under way.
There have been three major outputs from this project. The first is pertaining to grant writing. Our involvement in this multistate research project enabled us to compete for a large multiinstitutional grant, which is pending, and also to be awarded a large grant based on the work performed as part of this multistate project. The second output is the dissemination of knowledge through presentations, publications, and course lectures. The third is a set of laboratory techniques and equipment developed specifically for this research which will allow our lab to further explore these questions.
We currently have several potential set-ups for running algae studies. In our environmental chambers we have the ability to run with constant temperature and consistent lighting (16 h days, 8 h nights). This set-up is used for media development, strain selection, and inoculum preparation with cultures up to 400 mL and capacity of 123 flasks. We also have a varying temperature chamber, where the temperature of the cultures is varied using a circulating water bath through the metal base of the chamber. This system has consistent lighting (16 h days, 8 h nights) and uses cultures up to 400 mL with a capacity of up to 27 flasks. We also have a ventilated and constantly stirred system for use with lower flow rates, which also requires stirring. This set-up is also used with simulated flue gas experiments that need to be properly ventilated. This system utilizes cultures up to 400 mL with a capacity of up to 27 flasks. We also have a pilot-scale, continuously harvested system, which is currently under renovation. This system will be able to run a 60 L culture.
Clostridium thermocellum is a cellulolytic anaerobic bacterium that can directly convert cellulosic feedstock into ethanol. However, ethanol yield of this organism is low due to the reallocation of carbon to other fermentation products (lactate, acetate, formate), as well as gases (carbon dioxide, and hydrogen). C. thermocellum at elevated pressure (7.0 MPa, and 13.0 MPa) increased the ethanol: acetate ratio by more than 100-fold compared to that under atmospheric pressure. The observed effect has been attributed to the increased concentration of hydrogen in the culture broth. Hydrogen is hypothesized to inhibit hydrogenase.
To separate the increased hydrogen inhibition effect from the additional effect seen at pressure, our current work focuses on the effect of exogenous hydrogen and other hydrogenase inhibitors on the product formation of C. thermocellum. Preliminary batch experiments have shown that the ethanol: acetate ratio increased in the presence of exogenous hydrogen and hydrogenase inhibitors. Continuous fermentations will be carried out in a chemostat under treatments of different inhibitors at various pressures. The ability to control product selectivity by environmentally manipulating carbon and electron flows offers a novel approach to directing microbial metabolism.
Sharma, B., Nokes, S., Montross, M., and L. Vaillancourt. 2010. A real-time polymerase chain reaction protocol for quantifying growth of Fusarium graminearum during solid substrate cultivation on corn stover. Journal of Biotech Research, 2010. 2:144-155.
Dhamagadda, V. S., S.E. Nokes, H.J. Strobel, and M.D. Flythe. 2010. Investigation of the metabolic inhibition observed in solid substrate cultivation of Clostridium thermocellum on cellulose. Bioresource Technology. 101(15): 6039-6044.