Engineering Commons^™

Storage Of Round And Square Switchgrass Bales: Effect Of Storage Time And Fungal Inoculation On Saccharification Efficiency, Noaa Frederick

Graduate Theses and Dissertations

To produce fermentable sugars from lignocellulosic biomass feedstock, severe pretreatment conditions are needed (either high acid concentration, temperature, or retention times). High severities can produce toxic byproducts which inhibit enzymatic hydrolysis or fermentation. In order to reduce pretreatment severities (and thus increase enzyme and fermentation efficiency), the white-rot fungus Pleurotus ostreastus was seeded into square and round bales of Kanlow switchgrass (Panicum virgastum L.) and left in the field over a period of 9 month. The laccase producing fungus is believed to selectively degrade lignin, a common plant structural polymer, which can function as an enzymatic inhibitor. Samples were taken …

Influence Of Ultrasonics In Ammonia Steeped Switchgrass For Enzymatic Hydrolysis, Melissa Tabada Montalbo-Lomboy, Gowrishankar Srinivasan, D. Raj Raman, Robert P. Anex Jr., David A. Grewell

Gowrishankar Srinivasan

The bioconversion of lignocellulosic materials into fuels is of great environmental and economic importance, because of the large amounts of feedstock (est. over 1 billion tons per year), the potentially low cost of this feedstock, and the potentially high net energy balance the overall process. Switchgrass (Panicum virgatum L.) is a candidate dedicated lignocellulosic feedstock in the US. However, lignocellulosic materials, including switchgrass, are hampered by the recalcitrance of lignocellulose to enzymatic degradation into fermentable sugars. Various types of pretreatment have been developed to overcome this recalcitrance. In this study, we examined sequential ammonia-steeping and ultrasound pretreatment of switchgrass. The …

Economic And Environmental Optimization In The Supply Of Switchgrass In Tennessee, Jia Zhong

Masters Theses

The low efficiency of collection, storage and transportation in the switchgrass supply chain has hindered the commercialization of a switchgrass-based biofuel industry, even given its ecological and environmental advantages in carbon sequestrate, soil quality, water use, and pollution pressure. Thus, designing a switchgrass-based supply chain balancing both environmental and economic performance is important to expedite the development of the cellulosic biofuel industry to meet the national energy plan.

The objectives of this study are to 1) determine economic cost and multiple environmental outcomes in feedstock supply chains and 2) identify the relation between the economic and environmental performances. The first …

Modeling Water Quality For Switchgrass Crop Production: Implications For Bioenergy Sustainability In East Tennessee, Zachariah Tzvi Seiden

Masters Theses

With passing of the US Energy Independence and Security Act (EISA) of 2007, there has been considerable research conducted on the sustainability of bioenergy crop production in the United States; switchgrass has shown particular potential for bioenergy production in East Tennessee. Many studies evaluating the environmental impact switchgrass has on runoff and water quality use the Soil and Water Assessment Tool (SWAT) for watershed modeling. Because SWAT is a lumped watershed model, it evaluates the result of hydrological processes for each hydrologic response unit (HRU), without accounting for the physical interactions between these HRUs. The Water Erosion Prediction Project (WEPP) …

Influence Of Ultrasonics In Ammonia Steeped Switchgrass For Enzymatic Hydrolysis, Melissa Tabada Montalbo-Lomboy, Gowrishankar Srinivasan, D. Raj Raman, Robert P. Anex Jr., David A. Grewell

Gowrishankar Srinivasan

The bioconversion of lignocellulosic materials into fuels is of great environmental and economic importance, because of the large amounts of feedstock (est. over 1 billion tons per year), the potentially low cost of this feedstock, and the potentially high net energy balance the overall process. Switchgrass (Panicum virgatum L.) is a candidate dedicated lignocellulosic feedstock in the US. However, lignocellulosic materials, including switchgrass, are hampered by the recalcitrance of lignocellulose to enzymatic degradation into fermentable sugars. Various types of pretreatment have been developed to overcome this recalcitrance. In this study, we examined sequential ammonia-steeping and ultrasound pretreatment of switchgrass. The …

Vulnerability Of Crops And Native Grasses To Summer Drying In The U.S. Southern Great Plains, Naama Raz-Yaseef, Dave P. Billesbach, Marc L. Fischer, Sebastien C. Biraud, Stacey A. Gunter, James A. Bradford, Margaret S. Torn

Biological Systems Engineering: Papers and Publications

The Southern Great Plains are characterized by a fine-scale mixture of different land-cover types, predominantly winter-wheat and grazed pasture, with relatively small areas of other crops, native prairie, and switchgrass. Recent droughts and predictions of increased drought in the Southern Great Plains, especially during the summer months, raise concern for these ecosystems. We measured ecosystem carbon and water fluxes with eddy-covariance systems over cultivated cropland for 10 years, and over lightly grazed prairie and new switchgrass fields for 2 years each. Growing-season precipitation showed the strongest control over net carbon uptake for all ecosystems, but with a variable effect: grasses …