Farmers will supply the raw ingredients for the emerging cellulosic ethanol industry. The long-term relationship between a farmer and a processing firm is expected to be contractual. A processing firm has an incentive to sign long-term contracts to ensure a cost-efficient level of raw ingredient supply. However, farmers generally prefer to operate with either no contract or a short-term contract in order to maintain options for adjustments in future acreage allocations due to changes in relative prices. Of interest in this research is to understand the incentives of farmers and calculating the efficient level of the “inflexibility premium”, which a processing firm must provide to a farmer when a long term contract is signed. A stochastic dynamic programming model is solved and with the help of Microsoft Excel numerically evaluated to illustrate the marginal inflexibility premium is increasing with contract length and the level of price variability, and is decreasing with the size of acreage adjustment costs.

This study investigated the impacts of U.S. biofuel production and barge navigation impediments on agricultural transportation and markets. Both past and future impacts of U.S. biofuel production levels mandated by the Renewable Fuel Standards of the Energy Policy Act of 2005 (RFS1) and the Energy Independence and Security Act of 2007 (RFS2) were examined. Examination of barge navigations impediments included analysis of the impact of lock failure and low water levels on rivers due to drought, on agricultural transportation, and on consumer welfare. All scenarios were simulated using the International Grain Transportation Model, a price endogenous mathematical programming model. The results showed that RFS-associated (RFS1 and RFS2) U.S. corn ethanol production increased the total corn supply and diverted corn from non-ethanol consumption, reduced regional grain transportation volumes, and contributed to a rise in corn prices. The results of the forward-looking scenarios indicated that grain exports and transport volumes were increased. Exports from Gulf ports increased by 41%, while grain movements by rail increased by 60%. Additional investments in the expansion of the grain handling capacities of Gulf ports and the railroad industry are needed in the near future unless a large increase in biofuel production occurs. The results of navigation impediment scenarios indicated that both lock failures and low water levels on rivers adversely affect U.S. grain exports. The Gulf ports were most negatively impacted, relative to Pacific Northwest and Atlantic ports. Truck and barge freight volume declined while rail freight volume increased. Because trucks deliver grain from grain elevators to barge locations, truck volume also decreased in response to the decline in barge volume. The scenarios imposed welfare losses on society with most accruing to consumers, while the barge industry lost $10-154 million in revenue. The low water levels were more expensive than the lock failures. Major rehabilitation of the locks is needed to avoid lock failures and more dredging of the shallow parts of the river system is required because of frequent droughts.

Maternal consumption of alcohol during pregnancy is associated with alterations in fetal development that negatively impact the offspring causing neurochemical and neurobehavioural dysfunction termed fetal alcohol spectrum disorders; the most severe outcome is fetal alcohol syndrome. Changes in maternal and fetal hypothalamic-pituitary-adrenal (HPA) axis activation, induction of cytochrome P450 2E1 (CYP2E1) enzyme activity and alterations in micronutrient status, including folate, following chronic ethanol exposure (CEE) are key contributors to the neuroendocrine and neurobehavioural effects observed in offspring. This study tested the following hypotheses: Maternal consumption of ethanol throughout pregnancy can: alter maternal and fetal HPA axis function and induce CYP2E1 enzyme activity in the third-trimester-equivalent; decrease folate status in the maternal-fetal unit, which can be mitigated by folic acid supplementation; and cause neurobehavioural deficits in offspring at low-moderate dose of maternal ethanol consumption. These hypotheses were tested in the guinea pig, a well established model of ethanol neurobehavioural teratogenicity. CEE had no effect on maternal HPA axis function at any gestational day (GD). Fetal cortisol was unaffected by CEE, but did increase with gestational age in both CEE and control. CEE increased maternal and GD 65 fetal liver CYP2E1 enzyme activity. Maternal supplementation with folic acid did not mitigate CEE fetal growth restriction, but did increase maternal red blood cell (RBC) folate at term. At term, maternal supplementation prevented the CEE-induced decrease in fetal liver folate, did not affect fetal RBC folate, and did not mitigate the nutritional-deficit-induced decrease in fetal hippocampal folate. Maternal consumption of 5% (v/v) ethanol decreased offspring birth weight, increased spontaneous locomotor activity, increased preference for ethanol, and delayed learning on day two of Morris water maze testing in young adult offspring. These data indicate that, in the guinea pig: there is a threshold blood ethanol concentration for HPA axis activation; CEE can induce CYP2E1 in the GD 65 fetus; folic acid supplementation is not protective in this model of CEE; and low-moderate CEE can cause neurobehavioural perturbations in offspring. / Thesis (Ph.D, Pharmacology & Toxicology) -- Queen's University, 2012-05-31 14:38:44.391

Bioprocesses carried out for the production of fuels and other value-added co-products require effective process control strategies. The objective of this research is to apply Titrimetric Off-Gas Analysis (TOGA) for the on-line estimation of fermentation end products using Clostridium thermocellum. The hydrogen ion production, gaseous H2 and CO2, soluble H2 and CO2, as well as ethanol in the liquid phase and vapour phase, were monitored. All parameters, except the dissolved gases, showed good correlation with concurrent off-line analysis. The resulting mass and electron balances were close to theoretical values, and not significantly different from those determined using off-line analysis. Liquid-to-gas mass transfer limitations caused supersaturation of H2(aq) for a wide-range of operating conditions, and on average, ranged between 8-14 times the expected value at thermodynamic equilibrium. The supersaturation of CO2(aq) was conditional, and could be alleviated by increased sparging at agitation such that no significant mass transfer limitation was present. Simultaneous data on ethanol, CO2, and H2 could be obtained with the MIMS probe placed adjacent to the liquid surface in the reactor headspace. From this data, a metabolic model was proposed for the on-line estimation of formate and acetate using a mass balance and an electron balance. The model estimated formate concentrations with reasonable accuracy. Acetate predictions agreed with the qualitative trends, but the concentrations were inaccurate in comparison with off-line analysis. It was demonstrated that the sensor could provide on-line information on all major end-products synthesized by C. thermocellum. In conclusion, TOGA is a valuable instrument for the on-line monitoring and study of fermentation processes for cellulosic biofuels production

Despite the long-term economic and environmental benefits of cellulosic biofuel production, low rates of cellulose utilization and products syntheses are major techno-economical barriers to the commercialization. Optimized medium composition and low-cost nutrient source could greatly enhance the feasibility of large-scale biofuels synthesis by direct cellulose fermentation using a consolidated bioprocessing (CBP) approach. This study developed an improved growth medium for Clostridium thermocellum, an excellent cadidate for CBP that utilizes cellulose to produce ethanol, hydrogen, and other value-added biochemicals. An experimental design to determine the importance of nutrient components and concentrations on H2 and ethanol production from cellulose by C. thermocellum initially considered seven growth nutrients. Three most significant components - α-cellulose, yeast extract, and magnesium chloride were investigated in detail for their influence on rates and yields of H2 and ethanol production during cellulose fermentation by C. thermocellum. To explore individual and interactive effects of these nutrients on ethanol and hydrogen (H2) production, a central composite face-centered design and the response surface methodology was applied to predict optimum nutrient compositions for H2 and ethanol production. Experimental verification of predicted optima produced about 3-fold and 4-fold more H2 and ethanol respectively compared with the reference medium. These small-scale results were successfully verified in large-volume (7L), atmospheric cultures. Irrespective of culture conditions, relative improvement in rates and productivities of H2 and ethanol in optimized medium compared with reference medium were consistent with small-volume cultures. Various ethanol distillery co-products were tested for their potentials to replace expensive medium ingredients. Medium prepared with these co-products show excellent ability to suppport cell-growth and production of ethanol and H2 at concentrations equivalent to those generated from the reagent grade medium. Utilization of these low-cost nutrient sources to replace expensive reagent ingredients may potentially contribute to the viability of both grain-based ethanol and cellulosic biofuels. With medium optimization, scale-up and use of low-cost nutrient sources, this study represents one of the very few systematic research approaches to improve direct bioconversion of cellulosic biomass into biofuels.

Consolidated bioprocessing, a method that involves cellulase production, substrate hydrolysis, and fermentation all in one step, requires lower energy input and aims at achieving reduced biofuel production costs than traditional processes. It is an economically appealing strategy for the efficient production of biofuels such as ethanol or H2. At present, the yields of fermentative hydrogen and ethanol production are less than the theoretical maximum and vary between anaerobic Clostridia due to the presence of highly branched metabolic pathways. With the recent advancements in ‘Omic technologies, the selected cellulolytic species, in this case, C. termitidis, was extensively studied to identify the key enzymes that are involved in hydrogen and ethanol synthesis pathways in both the genome and proteome under different culture conditions. Metabolic characterization involving growth and end-product synthesis patterns were performed on 2 g L-1 cellobiose and α-cellulose under batch conditions to determine its metabolic potential for hydrogen and/or ethanol production. Initial characterization has shown the ability of C. termitidis to produce hydrogen, ethanol, and various other end-products on the two susbtrates. Continous N2 sparging in the pH-controlled bioreactors with cellobiose and α-cellulose showed a consistent increase in the H2 synthesis and lowered ethanol production compared to batch studies, with the H2 yields of 1.03 and 1.34 mol product per mol hexose equivalent added, respectively. Shotgun 2-D proteome analyses were performed to compare cellulose versus cellobiose grown cultures across exponential and stationary phases of growth. Most of the glycolytic proteins were detected in the proteome with some exceptions and no significant change was observed across both growth conditions. Hydrogen synthesis was regulatd via PFOR and ferredoxin-dependent hydrogenase, where as ethanol synthesis was regulated primarily via bifunctional AdhE activity. Proteomic analyses of C. termitidis cultured on hexose sugars in the absence of xylose suggested possible sequential utilization of xylose and cellobiose for the first time. Putative proteins consistent with xylose fermentation were observed at high levels. The hypothesis that C. termitidis can sequentially utilize xylose and cellobiose was further validated using batch fermentations tests on pure (xylose, cellobiose, xylan) and mixed substrates (xylose + cellobiose).

No abstract available. / Thesis (M. Sc.)-University of Durban-Westville, 1994.

Type 2 diabetes is now recognized as a worldwide epidemic. Pancreatic beta-cell decompensation in the presence of insulin resistance is a major mechanism for the development of type 2 diabetes and may be triggered by mitochondrial dysfunction. Alcoholism is a known risk factor for type 2 diabetes. Excessive or chronic alcohol consumption leads to increased oxidative stress and mitochondrial dysfunction in beta-cells. Prohibitin is a multifunctional protein that also regulates mitochondrial biogenesis and function. Although it has anti-oxidant effects in some cell types, its role in pancreatic beta-cells is not known. This study has investigated the effects of prohibitin in ethanol treated pancreatic beta-cells using RINm5F and INS-1E cell lines. Prohibitin was found to be expressed in pancreatic beta-cells with localization to the nucleus and the perinuclear area. Ethanol increased the expression of prohibitin and induced its translocation from the nucleus to the mitochondria. Ethanol, through its metabolism by alcohol dehydrogenase (ADH), increased oxidative stress and altered mitochondrial membrane potential, decreased the activity of mitochondrial respiratory complexes I and IV, and uncoupled energy production with resulting reduction in ATP production. This was associated with activation of the proinflammatory enzyme c-Jun N-terminal kinase and proapoptotic proteins Bax and caspase-3, leading to beta-cell apoptosis. Ethanol also reduced glucose induced insulin secretion without alteration of the beta-cell transcription factors PDX-1 and MafA. Treatment with exogenous prohibitin or cellular overexpression of endogenous prohibitin attenuated ADH activity, prevented the deleterious effects of ethanol on mitochondrial function and reduced apoptosis, whereas prohibitin knockdown enhanced ethanol-induced apoptosis. In addition, prohibitin per se increased PDX-1 and MafA levels. Through the above mechanisms, prohibitin restored glucose induced insulin secretion in ethanol exposed beta-cells. In brief, ethanol causes mitochondrial dysfunction and induces apoptosis in beta-cells, which result in a reduction of insulin secretion; whereas prohibitin prevents mitochondrial dysfunction, apoptosis, and -cell failure by stabilizing mitochondrial complexes I and IV and inhibiting ADH activity during ethanol metabolism. In addition, prohibitin in itself increases the levels of beta-cell transcription factors. As a consequence, prohibitin maintains normal pancreatic beta-cell function and could be useful in diabetes prevention and treatment.

The physical properties and the stability of alcohol containing emulsions made with sodium caseinate using two types of oil, canola oil and coconut oil, were investigated. The region of emulsion stability was presented on ternary phase diagrams. Emulsion stability was limited to emulsion compositions in the range of sodium caseinate solutions between 32-68 %wt, oil contents between 10-53 %wt and ethanol concentrations from 8 to 32 %wt. The type of oil had a minor effect on emulsion stability, but stability was sensitive to ethanol content and casein/oil ratio. Emulsions were classified as Newtonian fluids, with high ethanol content (> 20 %wt) being low viscosity and those of low ethanol content (< 20 %wt) being of high viscosity. Analysis of emulsion droplet sizes showed that the presence of ethanol affected the average droplet size. From lipid oxidation determinations, there was no clear correlation between casein/oil ratio and concentration of lipid hydroperoxides

Acquired Immunodeficiency Syndrome (AIDS) was first reported in the United States in 1981 and has since become a major worldwide epidemic. The typical course of HIV disease begins with a primary infection followed by a relatively long latency phase and finally ends in the advance phase also called AIDS. There are two aspects considered the most important in HIV pathogenesis, namely viral replication and CD4 + T cell depletion. During the latency phase, tumor necrosis factor (TNF ) has been shown to play a predominant role in HIV-1 replication and disease progression. Since ethanol is also an important risk factor and has been implicated in HIV-1 replication, we investigate the effects of ethanol on TNF inducible signaling associated with HIV-1 replication in human CD4 + T cells. We demonstrate that clinically relevant ethanol concentrations significantly potentiate TNF inducible NF B. Although ethanol effectively collaborated with TNF , by itself it does not have a direct effect on NF activation. The ethanol dependent potentiation of TNF inducible NF B nuclear translocation is observed to involve the enhanced degradation of I B . Additionally, the ethanol mediated potentiation of TNF inducible NF B activation is abrogated by the known antioxidant pyrrolidinedithiocarbamate (PDTC), suggesting an important mechanistic role for reactive oxygen species (ROS) in this process. In correspondence with its effect on NF B, ethanol is also able to significantly enhance HIV-1 long terminal repeat (HIV-1-LTR) dependent transcription induced by TNF . Apoptosis has been proposed as a critical mechanism for CD4 + T cell depletion in HIV pathogenesis. Ceramide, a sphingolipid metabolite, is a common apoptotic transducer involved in CD4 + T cell apoptosis. In the current study, we show that ceramide potently induces CD4 + T cell apoptosis through activating caspase 3, which may further increase Fas Ligand expression to amplify the apoptotic signaling. Interestingly, the apoptotic effect of ceramide is completely blocked by pretreatment with zinc and the underneath mechanism is suggested to be a direct inhibition of caspase 3 activity by zinc. Survival factors are equally important in the regulation of apoptotic process. We demonstrate that PI3-kinase/Akt pathway is indispensable for the survival of CD4 + T cells. Further, Akt kinase is significantly inactivated and downregulated in oxidative stress induced CD4 + T cell apoptosis. N-acetyl-cysteine (NAC) can rescue CD4 + T cell from H2O2 induced caspase 3 activation and apoptosis, while depletion of glutathione (GSH) exacerbate it. Overall, this work identifies several mechanisms underlying CD4 + T cell apoptosis and provides molecular basis for the role of ethanol as a cofactor that can adversely affect HIV-1 infection and pathogenesis.