Biotechnology Commons^™

Evaluation Of The Over-Expression Of A Miscanthus X Giganteus Ppdk (C4ppdk1) In Switchgrass (Panicum Virgatum) For Improved Cold Temperature C4 Photosynthesis, Mathew Christian Halter

Masters Theses

Switchgrass (Panicum virgatum) has been proposed as a potential biofuel feedstock to aid in the displacement of petroleum-based combustible fuels over the course of the next several decades. Improving the yield potential of this perennial grass is therefore of economic interest. Increased net ethanol yields can be achieved in cellulosic feedstocks via two means: 1. Improved sugar release from digestible cell wall materials, 2. Increased overall biomass yield. The latter is the subject of this study.

As a C4 photosynthetic plant, switchgrass is highly productive in the hot, humid climate of the southeastern United States. By bypassing the …

Understanding The Transcriptional Regulation Of Secondary Cell Wall Biosynthesis In The Model Grass Brachypodium Distachyon, Pubudu Handakumbura

Doctoral Dissertations

Secondary cell wall synthesis occurs in specialized cell types following completion of cell enlargement. By virtue of mechanical strength provided by a wall thickened with cellulose, hemicelluloses, and lignin, these cells can function as water-conducting vessels and provide structural support. Several transcription factor families regulate genes encoding wall synthesis enzymes. Certain NAC and MYB proteins directly bind upstream of structural genes and other transcription factors. The most detailed model of this regulatory network is established predominantly for a eudicot, Arabidopsis thaliana. In grasses, both the patterning and the composition of secondary cell walls are distinct from that of eudicots. …

The Exometabolome Of Clostridium Thermocellum Reveals Overflow Metabolism At High Cellulose Loading, Evert K. Holwerda, Philip G. Thorne, Daniel G. Olson, Daniel Amador-Noguez, Nancy L. Engle, Timothy J. Tschaplinski, Johannes P. Van Dijken, Lee R. Lynd

Dartmouth Scholarship

BackgroundClostridium thermocellum is a model thermophilic organism for the production of biofuels from lignocellulosic substrates. The majority of publications studying the physiology of this organism use substrate concentrations of ≤10 g/L. However, industrially relevant concentrations of substrate start at 100 g/L carbohydrate, which corresponds to approximately 150 g/L solids. To gain insight into the physiology of fermentation of high substrate concentrations, we studied the growth on, and utilization of high concentrations of crystalline cellulose varying from 50 to 100 g/L by C. thermocellum. .

Identifying, Monitoring, Quantifying And Converting Algae To Bio-Fuels In Bio-Reactors, Alice C. Jernigan

Graduate Theses and Dissertations

Growing algae as a source for bio-fuels has become an area of interest due to concerns about global warming and the reliability and ecology of the production of fossil fuels. Dried algae harvested from a pilot water quality improvement technology at the Rockaway Wastewater Treatment Facility in New York were examined as a source of carbohydrates and lipids for the production of bio-fuels in bio-reactors. The length of storage time, storage conditions, sugar and lipid extraction processes, and fuel production were studied. The results show that if the algae is stored dry (0.015 g/g algae even after a year in …

Comparative Efficiency And Driving Range Of Light- And Heavy-Duty Vehicles Powered With Biomass Energy Stored In Liquid Fuels Or Batteries, Mark Laser, Lee R. R. Lynd

Dartmouth Scholarship

This study addresses the question, "When using cellulosic biomass for vehicular transportation, which field-to-wheels pathway is more efficient: that using biofuels or that using bioelectricity?" In considering the question, the level of assumed technological maturity significantly affects the comparison, as does the intended transportation application. Results from the analysis indicate that for light-duty vehicles, over ranges typical in the United States today (e.g., 560-820 miles), field-to-wheels performance is similar, with some scenarios showing biofuel to be more efficient, and others indicating the two pathways to be essentially the same. Over the current range of heavy-duty vehicles, the field-to-wheels efficiency is …