UMD Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/3

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.

More information is available at Theses and Dissertations at University of Maryland Libraries.

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    Effect of Air on Rumen Gas Production
    (2021) Rha, Rachel Youngah; Kohn, Richard A; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Ruminants may swallow air as they eat and ruminate throughout the day. However, it is unclear as to how the introduction of oxygen impacts fermentation pathways, bacteria, and yeast within this mostly anaerobic environment. Therefore, the focus of this thesis was to study air’s impact on rumen fermentation and to determine if probiotics could offset air’s impact on digestibility. An in vitro analysis of air and probiotics indicated the main effect of air decreased digestibility, the main effect of probiotics had variable effects, and probiotics had significant interactions with air. The interactions suggested yeast employing a potential alternative pathway with the introduction of oxygen. Utilizing published literature, a static and dynamic mathematical model was built to further analyze digestibility, gas composition, and uptake of oxygen within the rumen. Future studies will further develop this model with in vivo studies to further interpretation and understanding of rumen fermentation’s complex system.
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    BUTANOL PRODUCTION FROM GLYCEROL BY Clostridium pasteurianum IN DEFINED CULTURE MEDIA- A PHENOTYPIC APPROACH.
    (2009) Ramos Sanchez, David Leonardo; Wang, Nam S; Chemical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The fluctuations in oil prices have stimulated the production of renewable biofuels, in particular the production of bioethanol and biodiesel. The production of biodiesel has expanded almost six fold in the past years. The ten wt% of the biodiesel process results in crude glycerol. Once a valuable product, nowadays glycerol is considered a waste and a surplus material. Its current low price makes it an attractive substrate for a fermentation process. Molecular genetics have unveiled new insights about solvent production in Clostridia. It has been recognized that endospore development and solvent formation share a regulatory mechanism. The solvent production, particularly the butanol fermentation of glycerol by Clostridium pasteurianum was studied. Taking advantage of the characteristics of the sporulation phenotype, the study of the butanol fermentation was approached. A relation between spore formation and butanol production was found in C. pasteurianum by applying molecular genetics concepts.