132 research outputs found

    Isolation, Preliminary Characterization and Preliminary Assessment of Scale-Up Potential of Photosynthetic Microalgae for the Production of Both Biofuels and Bio-Active Molecules in the U.S. and Canada: Cooperative Research and Development Final Report, CRADA Number CRD-10-372

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    Combustion flue gases are a major contributor to carbon dioxide emissions into the Earth's atmosphere, a factor that has been linked to the possible global climate change. It is, therefore, critical to begin thinking seriously about ways to reduce this influx into the atmosphere. Using carbon dioxide from fossil fuel combustion as a feedstock for the growth, photosynthetic microorganisms can provide a large sink for carbon assimilation as well as a feedstock for the production of significant levels of biofuels. Combining microalgal farming with fossil fuel energy production has great potential to diminish carbon dioxide releases into the atmosphere, as well as contribute to the production of biofuels (e.g., biodiesel, renewable diesel and gasoline and jet fuel) as well as valuable co-products such as animal feeds and green chemicals. CO2 capture may be a regulatory requirement in future new coal or natural gas power plants and will almost certainly become an opportunity for commerce, the results of such studies may provide industries in the US and Canada with both regulatory relief and business opportunities as well as the ability to meet environmental and regulatory requirements, and to produce large volumes of fuels and co-products

    Synthesis, characterization, and reactivity of a heterobimetallic organometallic complex with a trans bidentate ligand for catalytic carbon-hydrogen bond activation

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    Our group is interested in exploiting cis-alkynyl transition metals to form trans-bidentate ligands in order to explore C—H activation. The p-cymene-supported ruthenium(II) complex (p-cym)Ru(PMe3)(C22-py)2 (where C2-2-py = 2-ethynylpyridine) has been prepared and characterized by NMR spectroscopy. We are interested in the interaction of palladium(II) acetate utilizing the Ru(II) center as a hinge in order to force the pyridine ligands to act as a trans-bidentate ligand. The synthesis and characterization of (p-cym)Ru(PMe3)(C22-py)2, reactivity with Pd(OAc)2, and comparisons to the previously reported Cp*2Ti(C2-2-py)2

    Hydrogen production from the catalytic supercritical water gasification of process water generated from hydrothermal liquefaction of microalgae

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    The integration of hydrothermal liquefaction (HTL) and hydrothermal gasification (HTG) is an option for enhanced energy recovery and potential biocrude upgrading. The yields and product distribution obtained from the HTL of Chlorella vulgaris have been investigated. High conversion of algae to biocrude as well as near complete gasification of the remaining organic components in the aqueous phase was achieved. The aqueous phase from HTL was upgraded through catalytic HTG under supercritical water conditions to maximise hydrogen production for biocrude hydrotreating. High yields of hydrogen were produced (∼30 mol H2/kg algae) with near complete gasification of the organics (∼98%). The amount of hydrogen produced was compared to the amounts needed for complete hydrotreating of the biocrude. A maximum of 0.29 g H2 was produced through HTG per gram of biocrude produced by HTL. The nutrient content of the aqueous phase was analysed to determine suitability of nutrient recovery for algal growth. The results indicate the successful integration of HTL and HTG to produce excess hydrogen and maintain nutrient recovery for algal growth

    Renewable Diesel from Algal Lipids: An Integrated Baseline for Cost, Emissions, and Resource Potential from a Harmonized Model

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    The U.S. Department of Energy's Biomass Program has begun an initiative to obtain consistent quantitative metrics for algal biofuel production to establish an 'integrated baseline' by harmonizing and combining the Program's national resource assessment (RA), techno-economic analysis (TEA), and life-cycle analysis (LCA) models. The baseline attempts to represent a plausible near-term production scenario with freshwater microalgae growth, extraction of lipids, and conversion via hydroprocessing to produce a renewable diesel (RD) blendstock. Differences in the prior TEA and LCA models were reconciled (harmonized) and the RA model was used to prioritize and select the most favorable consortium of sites that supports production of 5 billion gallons per year of RD. Aligning the TEA and LCA models produced slightly higher costs and emissions compared to the pre-harmonized results. However, after then applying the productivities predicted by the RA model (13 g/m2/d on annual average vs. 25 g/m2/d in the original models), the integrated baseline resulted in markedly higher costs and emissions. The relationship between performance (cost and emissions) and either productivity or lipid fraction was found to be non-linear, and important implications on the TEA and LCA results were observed after introducing seasonal variability from the RA model. Increasing productivity and lipid fraction alone was insufficient to achieve cost and emission targets; however, combined with lower energy, less expensive alternative technology scenarios, emissions and costs were substantially reduced

    Transcriptional Analysis of Lactobacillus brevis to N-Butanol and Ferulic Acid Stress Responses

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    The presence of anti-microbial phenolic compounds, such as the model compound ferulic acid, in biomass hydrolysates pose significant challenges to the widespread use of biomass in conjunction with whole cell biocatalysis or fermentation. Currently, these inhibitory compounds must be removed through additional downstream processing or sufficiently diluted to create environments suitable for most industrially important microbial strains. Simultaneously, product toxicity must also be overcome to allow for efficient production of next generation biofuels such as n-butanol, isopropanol, and others from these low cost feedstocks.This study explores the high ferulic acid and n-butanol tolerance in Lactobacillus brevis, a lactic acid bacterium often found in fermentation processes, by global transcriptional response analysis. The transcriptional profile of L. brevis reveals that the presence of ferulic acid triggers the expression of currently uncharacterized membrane proteins, possibly in an effort to counteract ferulic acid induced changes in membrane fluidity and ion leakage. In contrast to the ferulic acid stress response, n-butanol challenges to growing cultures primarily induce genes within the fatty acid synthesis pathway and reduced the proportion of 19:1 cyclopropane fatty acid within the L. brevis membrane. Both inhibitors also triggered generalized stress responses. Separate attempts to alter flux through the Escherichia coli fatty acid synthesis by overexpressing acetyl-CoA carboxylase subunits and deleting cyclopropane fatty acid synthase (cfa) both failed to improve n-butanol tolerance in E. coli, indicating that additional components of the stress response are required to confer n-butanol resistance.Several promising routes for understanding both ferulic acid and n-butanol tolerance have been identified from L. brevis gene expression data. These insights may be used to guide further engineering of model industrial organisms to better tolerate both classes of inhibitors to enable facile production of biofuels from lignocellulosic biomass
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