The plant cell wall contains significant quantities of renewable polymers in the form of cellulose, hemicellulose, and lignin. These three renewable polymers have the potential to complement or replace synthetic polymers in a variety of applications. Rapidly determining the quantities of these polysaccharides in lignocellulosic biomass is important yet difficult since plant biomass is recalcitrant and highly variable in composition. Part of this contribution outlines a novel compositional analysis protocol using infrared spectroscopy and multivariate regression techniques that is rapid and inexpensive. Multivariate regression models based on calibration mixtures can be used to discern between populations of lignocellulosic biomass or to predict cellulose, hemicellulose, and lignin quantities. Thus, the compositional analysis step can be expedited so that other processes, like fractionation of the lignocellulose polymers, can be tuned accordingly to maximize the value of the final product. Hybrid materials were also generated using a variety of polymerization techniques and post-polymerization modifications. A novel controlled/living radical polymerization initiator was synthesized (2-bromo-2-methylpropane hydrazide) containing a hydrazide functionality that was covalently linked to the reducing-end of dextran. Despite the rapid coupling of the hydrazide- based initiator to the reducing-end of dextran, the instability of the alkyl bromide bond resulted in several unsuccessful attempts at Cu(0)-mediated controlled/living radical polymerization. Recommendations were given to improve the stability of this compound; however, an alternative approach to synthesizing hybrid copolymers was also investigated in parallel. Hyperbranched polymers were synthesized using commercially available vinyl and divinyl monomers in the presence of a cobalt(II) complex that enabled control over the size, architecture, and mol% of pendant vinyl groups amenable to post-polymerization modification. Modifying the ratio of divinyl monomer to cobalt(II) complex provided a series of hyperbranched polymers with variable morphology and mol% pendant vinyl groups. The pendant vinyl bonds were subsequently converted to amines via thiol additions with cysteamine. These amine functionalized hyperbranched polymers were then used in a subsequent reductive amination reaction with the reducing-end of dextran to produce the amphiphilic core-shell copolymer poly(methyl methacrylate-co-ethylene glycol dimethacrylate)-b-dextran. These amphiphilic copolymers mimicked the colloidal behaviour of conventional block copolymer micelles without requiring difficult syntheses or tedious self-assembly steps. / Thesis (Master, Chemical Engineering) -- Queen's University, 2012-02-28 11:20:01.568

In the current era, oil deficit countries around the world seriously consider shifting dependence from conventional gasoline to renewable bio-ethanol fuel in the transport industry. Arguably, blending l0vol% dry ethanol with 90vol% unleaded gasoline enables ethanol fuel to penetrate the fuel market at relatively lower development costs. Despite creating an important market for the ethanol industry, fuels containing dry ethanol of differential proportions multiply the local risks associated with fuel combustion. Making a sale of one drop of ethanol fuel, for example, is intrinsically tied to the sale of more drops of imported gasoline. Furthermore, an increase (decrease) in conventional fuel prices directly influences a decline (increase) in daily sales of ethanol fuel. Blending bio-ethanol fuel with conventional gasoline in various proportions fails to address the multifaceted fossil fuel crisis in oil deficit countries. Although reducing bio-ethanol production costs can buffer fuel prices to a significant degree when blended in higher ratios, industrial competition for bio-feedstock is a serious limitation for bio-ethanol development in all parts of the globe. Nevertheless, advances in biotechnology may allow the use of a wide range of cheaper ethanol feedstocks (e.g. lignocellulose) leading to an important reduction in ethanol production costs. Temporal and spatial variability of lignocellulosic ethanol potentials in the sugar industry is investigated over southern Africa as a whole. The influence of extremely low (high) production of sugar cane on the potentials development of lignocellulosic ethanol plants is demonstrated in this work. Characterization of bioethanol fuel markets on the basis of blending with gasoline is undertaken at the subcontinental scale. The connectivity between development, consumption per capita, population growth, bio-ethanol energy demand, as well as the critical limits of land stock potentials is examined in this study. On the basis of the special influence that each of the processes indicated above have on bio-ethanol fuel development, an integrated approach toward optimizing the total value of bio-ethanol fuel in the region is formulated. This approach allows the investigation to determine whether critical and beyond critical conditions of land stock lead to a collapse of a human consumption type or whether bio-ethanol fuel development is a totally viable process. Finally, this work ascertains whether sustainable biofuel development is an oxymoron because human development demands a constantly growing fuel consumption per capita, or because of increasing the lower limit, with an infinite upper limit for human development, or as a product of the combined effects of increasing human population with a higher consumption rate per capita of non-growing and non-developing land stock units. / Thesis (Ph.D.)-University of KwaZulu Natal, Durban, 2004.

Escherichia coli has a proven track record for successful production of anything from small molecules like organic acids to large therapeutic proteins, and has thus important applications in both R&amp;D and commercial production. The versatility of this organism in combination with the accumulated knowledge of its genome, metabolism and physiology, has allowed for development of specialty strains capable of performing very specific tasks, opening up opportunities within new areas. The work of this thesis has been devoted to alter membrane transport proteins and the regulation of these, in order for E. coli to find further application within two such important areas. The first area was vaccine development, where it was investigated if E. coli could be a natural vehicle for live vaccine production. The hypothesis was that the introduction and manipulation of a protein surface translocation system from pathogenic E. coli would result in stable expression levels of Salmonella subunit antigens on the surface of laboratory E. coli. While different antigen combinations were successfully expressed on the surface of E. coli, larger proteins were affected by proteolysis, which manipulation of cultivation conditions could reduce, but not eliminate completely. The surface expressed antigens were further capable of inducing proinflammatory responses in epithelial cells. The second area was biorefining. By altering the regulation of sugar assimilation, it was hypothesized that simultaneous uptake of the sugars present in lignocellulose hydrolyzates could be achieved, thereby improving the yield and productivity of important bio-based chemicals. The dual-layered catabolite repression was identified and successfully removed in the engineered E. coli, and the compound (R)-3-hydroxybutyric acid was produced from simultaneous assimilation of glucose, xylose and arabinose. / <p>QC 20150508</p>

Bioethanol is an appealing alternative to petroleum-based liquid fuel due to drivers such as environmental regulations and government mandates. Second generation lignocellulosic feedstocks are abundant, but their resistance to hydrolysis continues to be problematic. Different pretreatments have been proposed to increase cellulose reactivity. Softwood pine autohydrolyzed at different severities was subjected to further treatment to increase fibre reactivity. Liquid hot water is most effective at removing barriers, with the highest increase in sugar yield after enzymatic hydrolysis. Alkaline (NaOH) is found to be the worst option compared to dilute acid and organosolv. In addition, higher chemical concentrations and longer treatment times do not guarantee higher enzymatic hydrolysis yield. Process modifications such as fiber washing and multistage enzymatic hydrolysis are observed to be effective at increasing yield. However, more research is required to bring the enzymatic hydrolysis yield to a level where commercialization is feasible.

Bioethanol is an appealing alternative to petroleum-based liquid fuel due to drivers such as environmental regulations and government mandates. Second generation lignocellulosic feedstocks are abundant, but their resistance to hydrolysis continues to be problematic. Different pretreatments have been proposed to increase cellulose reactivity. Softwood pine autohydrolyzed at different severities was subjected to further treatment to increase fibre reactivity. Liquid hot water is most effective at removing barriers, with the highest increase in sugar yield after enzymatic hydrolysis. Alkaline (NaOH) is found to be the worst option compared to dilute acid and organosolv. In addition, higher chemical concentrations and longer treatment times do not guarantee higher enzymatic hydrolysis yield. Process modifications such as fiber washing and multistage enzymatic hydrolysis are observed to be effective at increasing yield. However, more research is required to bring the enzymatic hydrolysis yield to a level where commercialization is feasible.

Thesis (M.Eng.(Chemical Engineering))--University of Pretoria, 2008. / Includes bibliographical references.

Thesis (M.S.)--Mississippi State University. Department of Agricultural Economics. / Title from title screen. Includes bibliographical references.

Diss. (sammanfattning) Karlstad : Karlstads universitet, 2009. / Härtill 5 uppsatser.

Thesis (Ph. D.)--University of Washington, 1991. / Vita. Includes bibliographical references (leaves [102]-109).

The application of anaerobic digestion (AD) as a sustainable waste management technology is growing worldwide, due to high energy prices as well as increasingly strict environmental regulations. The growth of the AD industry necessitates exploring new substrates for their utilisation in AD processes. The present work investigates the AD of two recalcitrant biomass: lignocelluloses and keratin-rich residues. The complex nature of these waste streams limits their biological degradation; therefore, suitable pre-processing is required prior to the AD process.In the first part of the study, the effects of organic solvent pre-treatments on bioconversion of lignocelluloses (straw and forest residues) to biogas were evaluated. Pre-treatment with N-methylmorpholine-N-oxide (NMMO) resulted in minor changes in the composition of the substrates, while their digestibility significantly increased. Furthermore, due to the high cost of the NNMO, the effect of pre-treatment with the recycled solvent was also explored. Since it was found that the presence of small traces of NMMO in the system after the treatment has inhibitory effects on AD, pre-treatments of forest residues using other organic solvents, i.e. acetic acid, ethanol, and methanol, were investigated too. Although pre-treatments with acetic acid and ethanol led to the highest methane yields, the techno-economical evaluation of the process showed that pre-treatment with methanol was the most viable economically, primarily due to the lower cost of methanol, compared to that of the other solvents.In the second part of the work, wool textile wastes were subjected to biogas production. Wool is mainly composed of keratin, an extremely strong and resistible structural protein. Thermal, enzymatic and combined treatments were, therefore, performed to enhance the methane yield. The soluble protein content of the pre-treated samples showed that combined thermal and enzymatic treatments had significantly positive effects on wool degradation, resulting in the highest methane yields, i.e. 10–20-fold higher methane production, compared to that obtained from the untreated samples.In the last part of this thesis work, dry digestion of wheat straw and wool textile waste, as well as their co-digestion were studied. The total solid (TS) contents applied in the digesters were between 6–30% during the investigations. The volumetric methane productivity was significantly enhanced when the TS was increased from 6 to 13–21%. This can be a beneficial factor when considering the economic feasibility of large-scale dry AD processes.