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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A Petrographic Characterization of the Leatherwood Coal Bed in Eastern Kentucky

Johnston, Michelle N. 01 January 2014 (has links)
The Eastern Kentucky Coal Field is located in the central portion of the Appalachian Basin. The Pennsylvanian Breathitt Formation in this region is characterized by numerous sequences of bituminous coal-bearing sedimentary rocks. These coals have distinct maceral compositions due to variations in depositional environments. Coal characterization is an important method for determining conditions that influenced peat accumulation and overall depositional settings of mires. This study focuses on the characterization of the maceral composition of the Middle Pennsylvanian-age Leatherwood coal bed. It utilizes petrographical, palynological, and geochemical analyses to describe specific depositional environments and associated peat accumulation conditions. Petrographic analyses indicate that these coals have relatively high liptinite and varying inertinite content, along with trace amounts of mineral matter. Vitrinite, mainly in the form of collotelinite, is the most dominant maceral group. Geochemical data reveal low ash and sulfur content. Ancillary palynological data shows the palynomorph assemblage to be dominated by tree fern and large lycopsid tree spores, with lesser amounts of small lycopsid tree, small fern, and cordaites and calamites spores. The petrographic, geochemical and palynological data indicate that both domed, ombrotrophic, and planar, rheotrophic mire conditions, with limited local detrital influx, contributed to the formation of the Leatherwood coal.
2

Enzymes and Feedstocks for Sustainable Biomass Utilisation

Mottiar, Yaseen 15 August 2012 (has links)
Modern biorefineries provide a framework for the sustainable conversion of biomass to biofuels and biochemicals. In light of the recalcitrance of lignin in woody feedstocks, the native shrub eastern leatherwood is proposed as a model hypolignified species. Xylem tissue of this low-lignin plant contained syringyl-rich lignin that was more easily hydrolysed and did not appear to be localised in the middle lamellae. Also, leatherwood cellulose was less crystalline and the xylan was highly acetylated. While viable low-lignin plants will enable the sustainable utilisation of woody feedstocks, high-value bioproducts are needed to economise future biorefineries. The carbohydrate oxidoreductases galactose oxidase and glucooligosaccharide oxidase were studied for use in the oxidation and derivatisation of plant-derived polysaccharides for the production of such high-value bioproducts. The carbohydrate-binding module of galactose oxidase was necessary for recombinant protein production. Also, a mutant library of glucooligosaccharide oxidase variants was produced to generate enzymes with novel activity.
3

Enzymes and Feedstocks for Sustainable Biomass Utilisation

Mottiar, Yaseen 15 August 2012 (has links)
Modern biorefineries provide a framework for the sustainable conversion of biomass to biofuels and biochemicals. In light of the recalcitrance of lignin in woody feedstocks, the native shrub eastern leatherwood is proposed as a model hypolignified species. Xylem tissue of this low-lignin plant contained syringyl-rich lignin that was more easily hydrolysed and did not appear to be localised in the middle lamellae. Also, leatherwood cellulose was less crystalline and the xylan was highly acetylated. While viable low-lignin plants will enable the sustainable utilisation of woody feedstocks, high-value bioproducts are needed to economise future biorefineries. The carbohydrate oxidoreductases galactose oxidase and glucooligosaccharide oxidase were studied for use in the oxidation and derivatisation of plant-derived polysaccharides for the production of such high-value bioproducts. The carbohydrate-binding module of galactose oxidase was necessary for recombinant protein production. Also, a mutant library of glucooligosaccharide oxidase variants was produced to generate enzymes with novel activity.

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