Cellulose is the most plentiful biopolymer on the planet, and as such, is a large potential energy source. Converting cellulose into ethanol first requires the disruption of the crystallinity of cellulose fibers and subsequent hydrolysis into glucose. The glucose can then be fermented, producing ethanol. The conversion of cellulose fibers to glucose is an energy intensive and costly step, which is a barrier to industrial production of cellulosic ethanol. The use of enzymes to facilitate this conversion is a promising approach. In the present study, the action of individual enzymes and combinations of enzymes from the Hypocrea jecorina secretome on bacterial cellulose fibers has been studied, to better understand their individual and synergistic action. I have used a custom Surface Plasmon Resonance imaging (SPRi) device to measure changes in the thickness of cellulose fiber coverage of a thioglucose-functionalized gold substrate upon exposure to enzymes. The cellulose fibers were deposited using a Langmuir-Blodgett technique, resulting in non-uniform cellulose coverage of the substrate. By defining local Regions of Interest (ROIs) of the cellulose-covered gold film, and by measuring the SPR curves at elevated temperature for the ROIs as a function of time, we are able to determine the rate and extent of degradation of the cellulose fibers within individual ROIs. We have fit the change in SPR angle over time after exposure to enzyme to an exponential decay function that allows us to determine the average time constant of action of these enzymes on the deposited cellulose fibers. We have used the above procedure to measure the average time constants of action and the average degradation fraction (the change in average thickness divided by the initial average thickness) of cellulose fibers exposed to CBH-1, CBH-2, and EG-1, as well as combinations of these enzymes. We have measured an increase in the average degradation fraction and a decrease in the average time constants of action for cellulose fibers exposed to 23 μg/mL CBH-2 compared to fibers exposed to the same concentration of CBH-1. Additionally, for concurrent exposure of CBH-1 and EG-1 (with individual concentrations of 23 μg/mL), as well as concurrent introduction of CBH-1, CBH-2 and EG-1, we observed increases in the average degradation fraction and decreases in average time constants relative to the values measured for the individual enzymes. These measurements allow us to determine the relative activity of these enzymes and they demonstrate cooperativity and complementarity of action of the different enzymes.

The development of forest-based biorefineries has the potential to both provide a source of sustainable, low carbon fuel and increase the value drawn from wood residues to help revitalize the forest sector. There has been significant progress toward developing forest biorefining technologies, supported to some extent through government programs, though there are still several barriers to development. Realization of commercial-scale facilities however, will likely be limited by logistical constraints associated with maintaining a consistent supply of woody feedstock and the high capital cost of constructing the facility. To address this issue, mill clusters with sufficient processing capacity were located and evaluated for their suitability to house a forest biorefinery. Existing single-entity mill clusters in Canada were identified according to a set of criteria, and provide the basis for the analysis to determine feedstock supply costs and potential availability. The optimal biorefinery sites within each cluster were identified using a transportation module developed for this study and evaluated according to other factors that would affect the suitability of the site for a large scale forest biorefinery, such as access to markets, other available feedstocks and energy sources. There were four mill clusters identified in eastern Canada that have the potential to support a commercial forest biorefinery. A facility that is centrally located within one of the identified clusters would expect to have a feedstock cost ranging from approximately $95 to $110 per odt. A series of key informant interviews were carried out to further assess the cluster approach to forest biorefinery development. Interviewees generally agreed that the identified locations could potentially support a commercial biorefinery and suggested there are currently significant volumes of underutilized wood in these regions. Forest biorefinery development in the cluster regions, especially where there is mixed forest, should be further pursued. / Thesis (Master, Geography) -- Queen's University, 2013-12-30 17:39:57.326

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Hemicellulose, a plant cell wall polysaccharide composed amongst other 6-carbon sugars of xylose, a 5-carbon fermentable sugar, has various side-chains which hinder breakdown by the hydrolytic enzyme xylanase. We executed a screen of a metagenomic library established from heat treated saw dust to isolate novel genes for plant cell wall esterases and isolated two clones that potentially could be utilised as acetyl xylan esterases: HEL12 and HEL37 from Citrobacter farmeri and Bacillus vallismortis respectively are confirmed short-chain acetyl xylan esterases (C2-C4) with an optimal temperature of 30°C and 35°C and pH 8.0. HEL12 (33kDa) and HEL37 (25kDa) are small, dextrous acetyl xylan esterases with HEL37: Km of 1.621mM for p-nitrophenyl acetate and Km of 3.571mM for the substrate p-nitrophenyl palmitate with a Vmax of 2.462 mMol/min/mg protein and Vmax of 0.4363 mMol/min/mg protein respectively. In addition HEL12 was active on other substrates with a Km of 1.321mM protein for p-nitrophenyl acetate and Km of 1.692mM for the substrate p-nitrophenyl butyrate with a Vmax of 3.812 and Vmax of 1.523 mMol/min/mg protein respectively. Both enzymes were assayed on various acetylated polymers including acetylated xylan to indicate their ability to hydrolyse plant lignocellulosic polymers. / AFRIKAANSE OPSOMMING: Met die herwinde interisering in die energie krisis, is “herwinbare energie” vinnig besig om die nuwe modewoord te raak tussen verskeie industriële bedrywighede. Hemicellulose, ‘n plant sel wand polisakkaride opgemaak uit xilose, ‘n 5-koolstof fermenteerbare suiker, het verskillende sykettings wat ‘n hindernis veroorsaak in die hidrolase van die komponent deur xilanase ensieme. HEL12 en HEL37 van bakterieë Citrobacter farmeri en Bacillus vallismortis afsonderlik, is deel van die hidrolitiese groep van ensieme wat die hidrolisasie van ester sy-bindings op die xilaan suikerstring kataliseer. Die ensieme was primêr geassesseer vir aktiwiteit deur middel van sintetiese substraat 4-nitrofeniel asetaat. HEL12 en HEL37 was gevind om kort-ketting asetiel xilaan esterase (C2-C4) te wees, met ‘n optimale temperatuur van 30°C en 35°C afsonderlik, beide met ‘n optimale pH van 8.0. Met ‘n geskatte gewig van omtrent +- 30kDa is beide die ensieme van die kleiner meer behendige asetiel xilaan esterase, met HEL37: Km = 1.621 op 4-nitrofeniel asetaat en Km = 3.571 op substraat 4-nitrofeniel palmetaat, en Vmax = 2.462 met ‘n Vmax = 0.4363 afsonderlik, en HEL12: Km = 1.321 op 4-nitrofeniel asetaat en Km = 1.692 op sustraat 4-nitrofeniel buteraat met ‘n Vmax = 3.812 en Vmax = 1.523 afsonderlik.

Promoter effects on SBA-15 supported iron Fischer-Tropsch catalysts were investigated for their potential to improve high temperature catalyst performance. FTS catalysts promoted by manganese (0.15%-1.4%), copper (0.15%-1%), and potassium (0.5%-3%), with all percentages stated on the basis of mass percentage of final catalysts, were prepared and tested at 430°C and ambient pressure in a fixed bed reactor. Manganese showed the ability to promote the FT reaction, increasing both the CO conversion and the average chain length of hydrocarbon products. Compared to the unpromoted catalyst composed only of iron supported on SBA-15, 1.4%Mn (mass) promotion of 15% (mass) iron on SBA-15 improved CO conversion from 29% to 32%, increased alpha from 0.21 to 0.34, decreased carbon dioxide selectivity from 76% to 50%, increased C2-C4 selectivity from 9.6% to 30% and increased C5+ selectivity from 0.21% to 2.2%. Copper promotion gave increased conversion, but did not significantly affect alpha or carbon dioxide selectivity. Potassium promotion in the range of 0.5% to 3% by mass, on the other hand, had a negative effect on CO conversion at all concentrations tested.

Please read the summary in the front matter of this document. / Dissertation (MBA)--University of Pretoria, 2010. / Business Management / unrestricted

Magister Economicae - MEcon / Against the backdrop of rising fuel prices and increasing transport fuel demand, biofuel production, driven by the potential to contribute to energy security, climate change mitigation and rural development has experience rapid growth in recent years. Apart from a few private initiatives, South Africa has no commercialized biofuel industry to date. The concerns are that economic, environmental and socio economic issues can be a hindrance to the success of the industry. In response to these concerns this research intends to ascertain whether biofuel production could offer a viable economic alternative to fossil fuels in South Africa. For decision makers it is hard to find reliable reference material and solid guidance. Uncertainty over the potential risks and benefits has left potential investors unsure whether biofuel production could be a viable investment opportunity. The aim of this study was to determine if the benefits derived from biofuel production are significant enough to justify the substantial investment required. The findings reveal that in the absence of clear government strategies and the availability of low cost feedstocks the production of biofuel cannot be viewed as viable. The results show that bioethanol from grain sorghum and sugarcane are not economically viable since the results turn out to be negative in terms of both net present values (NPV) and internal rate of return (IRR) calculations, thus rendering a viable payback (PBP) period as unattainable. Similarly, the NPV and IRR for biodiesel from soya beans and sunflower is negative and the PBP also unattainable. Sensitivity analyses indicate that these crops (except for sunflowers) could only become viable if there were to be a substantial reduction in feedstock prices. All other changes in parameters would not render any of the production plant viable.

Biofuels were recently seen as a solution for the predicaments of our age; the “energy crisis” and the” climate change”. Today biofuels derived from food crops are a subject of debate for food hunger of the world’s poor and one of the main reasons of increased food prices. Latest studies also show that biofuels have no significant reduction in energy consumption and emissions. Today many attentions have been focused on biofuels extracted from biomass of different residual material such as agriculture residuals. Sweden produces biogas from different sources and also is one of the main users of Brazil’s bioethanol. In this report we aim to study two biofuel alternatives for Sweden transportation fleet; biogas from sugar beet residues in Sweden and imported bioethanol from sugarcanes from Brazil. The study is based on a life-cycle assessment (LCA) of the two mentioned biofuels. Three main units of agriculture, industrial production process and transportation is studied in the life cycle of the mentioned fuels. Based on energy inputs and emissions biogas from sugar beets in Sweden is a better alternative for Sweden transportation fleet. Bioethanol from Brazil is a crop-based fuel and highly energy consuming in the agricultural operations and industrial production process. Biogas fuel production requires increase in production capacity and technological developments.

Excess nitrogen and phosphorus in discharged wastewaters can lead to downstream eutrophication, ecosystem damage, and impaired water quality that may affect human health. Chemical-based and physical-based technologies are available to remove these nutrients; however, they often consume significant amounts of energy and chemicals, greatly increasing treatment costs. Algae are capable of removing these pollutants through biomass assimilation, and if harvested, can be utilized as a feedstock for biomethane or biodiesel production. Currently, difficulties in harvesting, concentrating, and dewatering algae have limited the development of an economically feasible treatment and production process. When algae are grown as surface-attached biofilms, the biomass is naturally concentrated and more easily harvested, leading to less expensive removal from treated water, and less expensive downstream processing for biofuel production. In this study, a novel algal biofilm production and harvesting system was designed, built, and tested. Key growth parameters were optimized in order to maximize biomass production and nutrient uptake from wastewater. Compared to suspended algae systems, the attached algal biofilm design of this study led to increased biomass production and greater treatment of domestic wastewater. An efficient and inexpensive algal biofilm harvesting technique was also developed in order to obtain a concentrated biosolids product, resulting in improved water quality and a feedstock suitable for further processing in the production of biofuels.

Growing demand for energy worldwide has increased interest in the production of renewable fuels, with microalgae representing a promising feedstock. The large-scale feasibility of microalgae based biofuels has previously been evaluated through technoeconomic and environmental impact assessments, with limited work performed on resource requirements. This study presents the use of a modular engineering system process model, founded on literature, to evaluate the nutrient (nitrogen and phosphorus) and carbon dioxide resource demand of five large-scale microalgae to biofuels production systems. The baseline scenario, representative of a near-term large-scale production system includes process models for growth, dewater, lipid extraction, anaerobic digestion, and biofuel conversion. Optimistic and conservative process scenarios are simulated to represent practical best and worst case system performance to bound the total resource demand of large-scale production. Baseline modeling results combined with current US nutrient availability from fertilizer and wastewater are used to perform a scalability assessment. Results show nutrient requirements represent a major barrier to the development of microalgae based biofuels to meet the US Department of Energy 2030 renewable fuel goal of 30% of transportation fuel, or 60 billion gallons per year. Specifically, results from the baseline and optimistic fuel production systems show wastewater sources can provide sufficient nutrients to produce 3.8 billion gallons and 13 billion gallons of fuel per year, corresponding to 6% and 22% of the DOE goal, respectively. High resource demand necessitates nutrient recovery from the lipid-extracted algae, thus limiting its use as a value-added co-product. Discussion focuses on system scalability, comparison of results to previous resource assessments, and model sensitivity of nutrient and carbon dioxide resource requirements to system parameter inputs.

No description available.