Dependency of climate change and carbon cycle on CO2 emission pathways

International Nuclear Information System (INIS)

Nohara, Daisuke; Yoshida, Yoshikatsu; Misumi, Kazuhiro; Ohba, Masamichi

2013-01-01

Previous research has indicated that the response of globally average temperature is approximately proportional to cumulative CO 2 emissions, yet evidence of the robustness of this relationship over a range of CO 2 emission pathways is lacking. To address this, we evaluate the dependency of climate and carbon cycle change on CO 2 emission pathways using a fully coupled climate–carbon cycle model. We design five idealized pathways (including an overshoot scenario for cumulative emissions), each of which levels off to final cumulative emissions of 2000 GtC. The cumulative emissions of the overshoot scenario reach 4000 GtC temporarily, subsequently reducing to 2000 GtC as a result of continuous negative emissions. Although we find that responses of climatic variables and the carbon cycle are largely independent of emission pathways, a much weakened Atlantic meridional overturning circulation (AMOC) is projected in the overshoot scenario despite cessation of emissions. This weakened AMOC is enhanced by rapid warming in the Arctic region due to considerable temporary elevation of atmospheric CO 2 concentration and induces the decline of surface air temperature and decrease of precipitation over the northern Atlantic and Europe region. Moreover, the weakened AMOC reduces CO 2 uptake by the Atlantic and Arctic oceans. However, the weakened AMOC contributes little to the global carbon cycle. In conclusion, although climate variations have been found to be dependent on emission pathways, the global carbon cycle is relatively independent of these emission pathways, at least superficially. (letter)

Genome-scale consequences of cofactor balancing in engineered pentose utilization pathways in Saccharomyces cerevisiae.

Directory of Open Access Journals (Sweden)

Amit Ghosh

Full Text Available Biofuels derived from lignocellulosic biomass offer promising alternative renewable energy sources for transportation fuels. Significant effort has been made to engineer Saccharomyces cerevisiae to efficiently ferment pentose sugars such as D-xylose and L-arabinose into biofuels such as ethanol through heterologous expression of the fungal D-xylose and L-arabinose pathways. However, one of the major bottlenecks in these fungal pathways is that the cofactors are not balanced, which contributes to inefficient utilization of pentose sugars. We utilized a genome-scale model of S. cerevisiae to predict the maximal achievable growth rate for cofactor balanced and imbalanced D-xylose and L-arabinose utilization pathways. Dynamic flux balance analysis (DFBA was used to simulate batch fermentation of glucose, D-xylose, and L-arabinose. The dynamic models and experimental results are in good agreement for the wild type and for the engineered D-xylose utilization pathway. Cofactor balancing the engineered D-xylose and L-arabinose utilization pathways simulated an increase in ethanol batch production of 24.7% while simultaneously reducing the predicted substrate utilization time by 70%. Furthermore, the effects of cofactor balancing the engineered pentose utilization pathways were evaluated throughout the genome-scale metabolic network. This work not only provides new insights to the global network effects of cofactor balancing but also provides useful guidelines for engineering a recombinant yeast strain with cofactor balanced engineered pathways that efficiently co-utilizes pentose and hexose sugars for biofuels production. Experimental switching of cofactor usage in enzymes has been demonstrated, but is a time-consuming effort. Therefore, systems biology models that can predict the likely outcome of such strain engineering efforts are highly useful for motivating which efforts are likely to be worth the significant time investment.

Bacterial carbon utilization in vertical subsurface flow constructed wetlands.

Science.gov (United States)

Tietz, Alexandra; Langergraber, Günter; Watzinger, Andrea; Haberl, Raimund; Kirschner, Alexander K T

2008-03-01

Subsurface vertical flow constructed wetlands with intermittent loading are considered as state of the art and can comply with stringent effluent requirements. It is usually assumed that microbial activity in the filter body of constructed wetlands, responsible for the removal of carbon and nitrogen, relies mainly on bacterially mediated transformations. However, little quantitative information is available on the distribution of bacterial biomass and production in the "black-box" constructed wetland. The spatial distribution of bacterial carbon utilization, based on bacterial (14)C-leucine incorporation measurements, was investigated for the filter body of planted and unplanted indoor pilot-scale constructed wetlands, as well as for a planted outdoor constructed wetland. A simple mass-balance approach was applied to explain the bacterially catalysed organic matter degradation in this system by comparing estimated bacterial carbon utilization rates with simultaneously measured carbon reduction values. The pilot-scale constructed wetlands proved to be a suitable model system for investigating microbial carbon utilization in constructed wetlands. Under an ideal operating mode, the bulk of bacterial productivity occurred within the first 10cm of the filter body. Plants seemed to have no significant influence on productivity and biomass of bacteria, as well as on wastewater total organic carbon removal.

Generation, capture, and utilization of industrial carbon dioxide.

Science.gov (United States)

Hunt, Andrew J; Sin, Emily H K; Marriott, Ray; Clark, James H

2010-03-22

efficiency and lower per capita consumption, and replacing fossil energy sources with sources such as wind, wave, and solar, respectively). "Low carbon" is of inherently less value to the chemical and plastics industries at least in terms of raw materials although a version of (2), the use of biomass, does apply, especially if we use carbon sources that are renewable on a human timescale. There is however, another renewable, natural source of carbon that is widely available and for which greater utilization would help restore material balance and the natural cycle for carbon in terms of resource and waste. CO(2), perhaps the most widely discussed and feared chemical in modern society, is as fundamental to our survival as water, and like water we need to better understand the human as well as natural production and consumption of CO(2) so that we can attempt to get these into a sustainable balance. Current utilization of this valuable resource by the chemical industry is only 90 megatonne per year, compared to the 26.3 gigatonne CO(2) generated annually by combustion of fossil fuels for energy generation, as such significant opportunities exist for increased utilization of CO(2) generated from industrial processes. It is also essential that renewable energy is used if CO(2) is to be utilized as a C1 building block.

Engineering Escherichia coli to grow constitutively on D-xylose using the carbon-efficient Weimberg pathway

Science.gov (United States)

Rossoni, Luca; Carr, Reuben; Baxter, Scott; Cortis, Roxann; Thorpe, Thomas; Eastham, Graham; Stephens, Gill

2018-01-01

Bio-production of fuels and chemicals from lignocellulosic C5 sugars usually requires the use of the pentose phosphate pathway (PPP) to produce pyruvate. Unfortunately, the oxidation of pyruvate to acetyl-coenzyme A results in the loss of 33 % of the carbon as CO2, to the detriment of sustainability and process economics. To improve atom efficiency, we engineered Escherichia coli to utilize d-xylose constitutively using the Weimberg pathway, to allow direct production of 2-oxoglutarate without CO2 loss. After confirming enzyme expression in vitro, the pathway expression was optimized in vivo using a combinatorial approach, by screening a range of constitutive promoters whilst systematically varying the gene order. A PPP-deficient (ΔxylAB), 2-oxoglutarate auxotroph (Δicd) was used as the host strain, so that growth on d-xylose depended on the expression of the Weimberg pathway, and variants expressing Caulobacter crescentus xylXAB could be selected on minimal agar plates. The strains were isolated and high-throughput measurement of the growth rates on d-xylose was used to identify the fastest growing variant. This strain contained the pL promoter, with C. crescentus xylA at the first position in the synthetic operon, and grew at 42 % of the rate on d-xylose compared to wild-type E. coli using the PPP. Remarkably, the biomass yield was improved by 53.5 % compared with the wild-type upon restoration of icd activity. Therefore, the strain grows efficiently and constitutively on d-xylose, and offers great potential for use as a new host strain to engineer carbon-efficient production of fuels and chemicals via the Weimberg pathway. PMID:29458683

Application of a systematic methodology for sustainable carbon dioxide utilization process design

DEFF Research Database (Denmark)

Plaza, Cristina Calvera; Frauzem, Rebecca; Gani, Rafiqul

than carbon capture and storage. To achieve this a methodology is developed to design sustainable carbon dioxide utilization processes. First, the information on the possible utilization alternatives is collected, including the economic potential of the process and the carbon dioxide emissions...... emission are desired in order to reduce the carbon dioxide emissions. Using this estimated preliminary evaluation, the top processes, with the most negative carbon dioxide emission are investigated by rigorous detailed simulation to evaluate the net carbon dioxide emissions. Once the base case design...

Pathway To Low-Carbon Lignite Utilization; U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL) Cooperative Agreement No. DE-FE0024233

Energy Technology Data Exchange (ETDEWEB)

Kay, John [Univ. of North Dakota, Grand Forks, ND (United States); Stanislowski, Joshua [Univ. of North Dakota, Grand Forks, ND (United States); Tolbert, Scott [Univ. of North Dakota, Grand Forks, ND (United States); Fiala, Nathan [Univ. of North Dakota, Grand Forks, ND (United States); Patel, Nikhil [Univ. of North Dakota, Grand Forks, ND (United States); Laumb, Jason [Univ. of North Dakota, Grand Forks, ND (United States)

2017-05-31

Utilities continue to investigate ways to decrease their carbon footprint. Carbon capture and storage (CCS) can enable existing power generation facilities to maintain operations and address carbon reduction. Subtask 2.1 – Pathway to Low-Carbon Lignite Utilization focused on several research areas in an effort to find ways to decrease the cost of capture across both precombustion and postcombustion platforms. Two postcombustion capture solvents were tested, one from CO₂ Solutions Inc. and one from ARCTECH, Inc. The CO₂ Solutions solvent had been evaluated previously, and the company had incorporated the concept of a rotating packed bed (RPB) to replace the traditional packed columns typically used. In the limited testing performed at the Energy & Environmental Research Center (EERC), no CO₂ reduction benefit was seen from the RPB; however, if the technology could be scaled up, it may introduce some savings in capital expense and overall system footprint. Rudimentary tests were conducted with the ARCTECH solvent to evaluate if it could be utilized in a spray tower configuration contactor and capture CO₂, SO₂, and NO_x. This solvent after loading can be processed to make an additional product to filter wastewater, providing a second-tier usable product. Modeling of the RPB process for scaling to a 550-MW power system was also conducted. The reduced cost of RPB systems combined with a smaller footprint highlight the potential for reducing the cost of capturing CO₂; however, more extensive testing is needed to truly evaluate their potential for use at full scale. Hydrogen separation membranes from Commonwealth Scientific and Industrial Research Organisation (CSIRO) were evaluated through precombustion testing. These had also been previously tested and were improved by CSIRO for this test campaign. They are composed of vanadium alloy, which is less expensive than the palladium alloys that are

Measures for carbon dioxide problem and utilization of energy

International Nuclear Information System (INIS)

Kojima, Toshinori

1992-01-01

As global environment problems, there are water, expansion of deserts, weather, tropical forests, wild animals, ocean pollution, nuclear waste contamination, acid rain, ozone layer and so on, and population, foods, energy, and resources are the problems surrounding them. It is clear that these origins are attributed to the development and consumption largely dependent on the intention of developed countries and the population problem of developing countries. In this report, the discharge of carbon dioxide that causes greenhouse effect and its relation with energy are discussed. The increase of carbon dioxide concentration, its release from fossil fuel, the destruction of forests, the balance of carbon on the earth, the development of new energy such as solar energy, the transport of new energy, secondary energy system and the role of carbon dioxide, the transfer to low carbon fuel and the carbon reduction treatment of fuel, the utilization of unused energy and energy price, the efficiency of energy utilization, the heightening of efficiency of energy conversion, energy conservation and the breakaway from energy wasteful use culture, and the recovery, preservation and use of discharged carbon dioxide are described. (K.I.)

Transporter engineering in biomass utilization by yeast.

Science.gov (United States)

Hara, Kiyotaka Y; Kobayashi, Jyumpei; Yamada, Ryosuke; Sasaki, Daisuke; Kuriya, Yuki; Hirono-Hara, Yoko; Ishii, Jun; Araki, Michihiro; Kondo, Akihiko

2017-11-01

Biomass resources are attractive carbon sources for bioproduction because of their sustainability. Many studies have been performed using biomass resources to produce sugars as carbon sources for cell factories. Expression of biomass hydrolyzing enzymes in cell factories is an important approach for constructing biomass-utilizing bioprocesses because external addition of these enzymes is expensive. In particular, yeasts have been extensively engineered to be cell factories that directly utilize biomass because of their manageable responses to many genetic engineering tools, such as gene expression, deletion and editing. Biomass utilizing bioprocesses have also been developed using these genetic engineering tools to construct metabolic pathways. However, sugar input and product output from these cells are critical factors for improving bioproduction along with biomass utilization and metabolic pathways. Transporters are key components for efficient input and output activities. In this review, we focus on transporter engineering in yeast to enhance bioproduction from biomass resources. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Branching points for transition pathways: assessing responses of actors to challenges on pathways to a low carbon future

International Nuclear Information System (INIS)

Foxon, Timothy J.; Pearson, Peter J.G.; Arapostathis, Stathis; Carlsson-Hyslop, Anna; Thornton, Judith

2013-01-01

This paper describes initial analysis of branching points on a set of transition pathways to a UK low carbon electricity future by 2050. As described in other papers in this special issue, we are exploring and analysing a set of core transition pathways, based on alternative governance patterns in which the ‘logics’ of market actors, government actors and civil society actors, respectively dominate. This core pathway analysis is enhanced by analyses of branching points within and across the pathways, which informs how competition between different logics plays out at key decision points. Branching points are defined as key decision points at which choices made by actors, in response to internal or external stresses or triggers, determine whether and in what ways the pathway is followed. A set of initial branching points for our three core transition pathways is identified through project and stakeholder workshops, and drawing on analysis of actors’ choices and responses at past branching points in energy system transitions. The potential responses of the actors are identified at these branching points, and risk mitigation strategies are formulated for the dominant actors to reinforce that pathway, as well as opportunities for actors to move away from the pathway. - Highlights: Transition Pathways is analysing three potential pathways to a low carbon future. ► Stresses lead to branching points, where actors make choices, creating pathways. ► These choices may lead to path-dependency. ► Differences in governance logics within transition pathways are also analysed. ► Studying branching points adds theoretical understanding and policy relevance to TP.

NapA Mediates a Redox Regulation of the Antioxidant Response, Carbon Utilization and Development in Aspergillus nidulans

Directory of Open Access Journals (Sweden)

Ariann E. Mendoza-Martínez

2017-03-01

Full Text Available The redox-regulated transcription factors (TFs of the bZIP AP1 family, such as yeast Yap1 and fission yeast Pap1, are activated by peroxiredoxin proteins (Prxs to regulate the antioxidant response. Previously, Aspergillus nidulans mutants lacking the Yap1 ortholog NapA have been characterized as sensitive to H2O2 and menadione. Here we study NapA roles in relation to TFs SrrA and AtfA, also involved in oxidant detoxification, showing that these TFs play different roles in oxidative stress resistance, catalase gene regulation and development, during A. nidulans life cycle. We also uncover novel NapA roles in repression of sexual development, normal conidiation, conidial mRNA accumulation, and carbon utilization. The phenotypic characterization of ΔgpxA, ΔtpxA, and ΔtpxB single, double and triple peroxiredoxin mutants in wild type or ΔnapA backgrounds shows that none of these Prxs is required for NapA function in H2O2 and menadione resistance. However, these Prxs participate in a minor NapA-independent H2O2 resistance pathway and NapA and TpxA appear to regulate conidiation along the same route. Using transcriptomic analysis we show that during conidial development NapA-dependent gene expression pattern is different from canonical oxidative stress patterns. In the course of conidiation, NapA is required for regulation of at least 214 genes, including ethanol utilization genes alcR, alcA and aldA, and large sets of genes encoding proteins involved in transcriptional regulation, drug detoxification, carbohydrate utilization and secondary metabolism, comprising multiple oxidoreductases, membrane transporters and hydrolases. In agreement with this, ΔnapA mutants fail to grow or grow very poorly in ethanol, arabinose or fructose as sole carbon sources. Moreover, we show that NapA nuclear localization is induced not only by oxidative stress but also by growth in ethanol and by carbon starvation. Together with our previous work, these results show

Production of Odd-Carbon Dicarboxylic Acids in Escherichia coli Using an Engineered Biotin-Fatty Acid Biosynthetic Pathway.

Science.gov (United States)

Haushalter, Robert W; Phelan, Ryan M; Hoh, Kristina M; Su, Cindy; Wang, George; Baidoo, Edward E K; Keasling, Jay D

2017-04-05

Dicarboxylic acids are commodity chemicals used in the production of plastics, polyesters, nylons, fragrances, and medications. Bio-based routes to dicarboxylic acids are gaining attention due to environmental concerns about petroleum-based production of these compounds. Some industrial applications require dicarboxylic acids with specific carbon chain lengths, including odd-carbon species. Biosynthetic pathways involving cytochrome P450-catalyzed oxidation of fatty acids in yeast and bacteria have been reported, but these systems produce almost exclusively even-carbon species. Here we report a novel pathway to odd-carbon dicarboxylic acids directly from glucose in Escherichia coli by employing an engineered pathway combining enzymes from biotin and fatty acid synthesis. Optimization of the pathway will lead to industrial strains for the production of valuable odd-carbon diacids.

Estimating environmental co-benefits of U.S. low-carbon pathways using an integrated assessment model with state-level resolution.

Science.gov (United States)

Ou, Yang; Shi, Wenjing; Smith, Steven J; Ledna, Catherine M; West, J Jason; Nolte, Christopher G; Loughlin, Daniel H

2018-04-15

There are many technological pathways that can lead to reduced carbon dioxide emissions. However, these pathways can have substantially different impacts on other environmental endpoints, such as air quality and energy-related water demand. This study uses an integrated assessment model with state-level resolution of the energy system to compare environmental impacts of alternative low-carbon pathways for the United States. One set of pathways emphasizes nuclear energy and carbon capture and storage, while another set emphasizes renewable energy, including wind, solar, geothermal power, and bioenergy. These are compared with pathways in which all technologies are available. Air pollutant emissions, mortality costs attributable to particulate matter smaller than 2.5 μm in diameter, and energy-related water demands are evaluated for 50% and 80% carbon dioxide reduction targets in 2050. The renewable low-carbon pathways require less water withdrawal and consumption than the nuclear and carbon capture pathways. However, the renewable low-carbon pathways modeled in this study produce higher particulate matter-related mortality costs due to greater use of biomass in residential heating. Environmental co-benefits differ among states because of factors such as existing technology stock, resource availability, and environmental and energy policies.

Variable Responses to Carbon Utilization between Planktonic and Biofilm Cells of a Human Carrier Strain of Salmonella enterica Serovar Typhi.

Directory of Open Access Journals (Sweden)

Kalaivani Kalai Chelvam

Full Text Available Salmonella enterica serovar Typhi (S. Typhi is a foodborne pathogen that causes typhoid fever and infects only humans. The ability of S. Typhi to survive outside the human host remains unclear, particularly in human carrier strains. In this study, we have investigated the catabolic activity of a human carrier S. Typhi strain in both planktonic and biofilm cells using the high-throughput Biolog Phenotype MicroArray, Minimum Biofilm Eradication Concentration (MBEC biofilm inoculator (96-well peg lid and whole genome sequence data. Additional strains of S. Typhi were tested to further validate the variation of catabolism in selected carbon substrates in the different bacterial growth phases. The analyzes of the carbon utilization data indicated that planktonic cells of the carrier strain, S. Typhi CR0044 could utilize a broader range of carbon substrates compared to biofilm cells. Pyruvic acid and succinic acid which are related to energy metabolism were actively catabolised in the planktonic stage compared to biofilm stage. On the other hand, glycerol, L-fucose, L-rhamnose (carbohydrates and D-threonine (amino acid were more actively catabolised by biofilm cells compared to planktonic cells. Notably, dextrin and pectin could induce strong biofilm formation in the human carrier strain of S. Typhi. However, pectin could not induce formation of biofilm in the other S. Typhi strains. Phenome data showed the utilization of certain carbon substrates which was supported by the presence of the catabolism-associated genes in S. Typhi CR0044. In conclusion, the findings showed the differential carbon utilization between planktonic and biofilm cells of a S. Typhi human carrier strain. The differences found in the carbon utilization profiles suggested that S. Typhi uses substrates mainly found in the human biliary mucus glycoprotein, gallbladder, liver and cortex of the kidney of the human host. The observed diversity in the carbon catabolism profiles among

The role of utilities in developing low carbon, electric megacities

International Nuclear Information System (INIS)

Kennedy, Chris; Stewart, Iain D.; Facchini, Angelo; Mele, Renata

2017-01-01

Development of electric cities, with low carbon power supply, is a key strategy for reducing global CO2 emissions. We analyze the role of electric utilities as important actors to catalyze the transition to electric cites, drawing upon data for the world's 27 megacities. Progress towards the ideal electric city is most advanced for Paris, Rio de Janeiro, Sao Paulo and Buenos Aires for low carbon electricity, while Indian megacities have relatively high use of carbon-intensive electricity as a percentage of total energy use. There is wide variety in the structure of markets for electricity provision in megacities, with a dominant, public utility being the most common model. We review literature on electricity sector business models and broadly propose future models dependent on the predominance of locally dispersed generation and the nature of the ownership of the electric grid within the city. Where a high proportion of electricity can be provided by locally distributed supply within a city, the role of utilities could predominantly become that of enabler of exchange with the grid, but new pricing structures are required. A further challenge for utilities in enabling the electric city is to provide a higher level of resilience to events that disrupt power supply. - Highlights: • Amongst 27 megacities, Paris, Rio, Sao Paulo and Buenos Aires are most progressed low carbon electric cities. • Indian megacities have relatively high use of electricity as a percentage of total energy use. • Wide variety in electricity market structure in megacities; dominant, public utility the most common model. • Utilities could become enablers of exchange with the grid, but new pricing models required.

Turning sunlight into stone: the oxalate-carbonate pathway in a tropical tree ecosystem

Directory of Open Access Journals (Sweden)

G. Cailleau

2011-07-01

Full Text Available An African oxalogenic tree, the iroko tree (Milicia excelsa, has the property to enhance carbonate precipitation in tropical oxisols, where such accumulations are not expected due to the acidic conditions in these types of soils. This uncommon process is linked to the oxalate-carbonate pathway, which increases soil pH through oxalate oxidation. In order to investigate the oxalate-carbonate pathway in the iroko system, fluxes of matter have been identified, described, and evaluated from field to microscopic scales. In the first centimeters of the soil profile, decaying of the organic matter allows the release of whewellite crystals, mainly due to the action of termites and saprophytic fungi. In addition, a concomitant flux of carbonate formed in wood tissues contributes to the carbonate flux and is identified as a direct consequence of wood feeding by termites. Nevertheless, calcite biomineralization of the tree is not a consequence of in situ oxalate consumption, but rather related to the oxalate oxidation inside the upper part of the soil. The consequence of this oxidation is the presence of carbonate ions in the soil solution pumped through the roots, leading to preferential mineralization of the roots and the trunk base. An ideal scenario for the iroko biomineralization and soil carbonate accumulation starts with oxalatization: as the iroko tree grows, the organic matter flux to the soil constitutes the litter, and an oxalate pool is formed on the forest ground. Then, wood rotting agents (mainly termites, saprophytic fungi, and bacteria release significant amounts of oxalate crystals from decaying plant tissues. In addition, some of these agents are themselves producers of oxalate (e.g. fungi. Both processes contribute to a soil pool of "available" oxalate crystals. Oxalate consumption by oxalotrophic bacteria can then start. Carbonate and calcium ions present in the soil solution represent the end products of the oxalate-carbonate

B-Cell-Specific Diversion of Glucose Carbon Utilization Reveals a Unique Vulnerability in B Cell Malignancies.

Science.gov (United States)

Xiao, Gang; Chan, Lai N; Klemm, Lars; Braas, Daniel; Chen, Zhengshan; Geng, Huimin; Zhang, Qiuyi Chen; Aghajanirefah, Ali; Cosgun, Kadriye Nehir; Sadras, Teresa; Lee, Jaewoong; Mirzapoiazova, Tamara; Salgia, Ravi; Ernst, Thomas; Hochhaus, Andreas; Jumaa, Hassan; Jiang, Xiaoyan; Weinstock, David M; Graeber, Thomas G; Müschen, Markus

2018-04-05

B cell activation during normal immune responses and oncogenic transformation impose increased metabolic demands on B cells and their ability to retain redox homeostasis. While the serine/threonine-protein phosphatase 2A (PP2A) was identified as a tumor suppressor in multiple types of cancer, our genetic studies revealed an essential role of PP2A in B cell tumors. Thereby, PP2A redirects glucose carbon utilization from glycolysis to the pentose phosphate pathway (PPP) to salvage oxidative stress. This unique vulnerability reflects constitutively low PPP activity in B cells and transcriptional repression of G6PD and other key PPP enzymes by the B cell transcription factors PAX5 and IKZF1. Reflecting B-cell-specific transcriptional PPP-repression, glucose carbon utilization in B cells is heavily skewed in favor of glycolysis resulting in lack of PPP-dependent antioxidant protection. These findings reveal a gatekeeper function of the PPP in a broad range of B cell malignancies that can be efficiently targeted by small molecule inhibition of PP2A and G6PD. Copyright © 2018 Elsevier Inc. All rights reserved.

Pathways for implementing REDD+. Experiences from carbon markets and communities

Energy Technology Data Exchange (ETDEWEB)

Zhu, X; Ravnkilde Moeller, L; Lopez, T De; Romero, M Z

2011-07-01

This issue of Carbon Market Perspectives on 'Pathways for implementing REDD+: Experience from carbon markets and communities' discusses the role of carbon markets in scaling up investments for REDD+ in developing countries. Nine articles authored by experienced negotiators on REDD+, carbon market actors, project developers and other leading experts share experiences and make suggestions on the key elements of a future international REDD+ regime: Architecture and underlying principles, measuring, reporting and verification (MRV), private-sector involvement, the rights of indigenous people and local communities, biodiversity conservation and environmental integrity. The articles are grouped under three main topics: the lessons of existing REDD+ projects; the future REDD+ regime and the role of carbon markets; and experiences and ideas about the involvement of indigenous people and local communities. (LN)

Lipid Biomarkers and Molecular Carbon Isotopes for Elucidating Carbon Cycling Pathways in Hydrothermal Vents

Science.gov (United States)

Zhang, C. L.; Dai, J.; Campbell, B.; Cary, C.; Sun, M.

2003-12-01

Increasing molecular evidence suggests that hydrothermal vents in mid-ocean ridges harbor large populations of free-living bacteria, particularly the epsilon Proteobacteria. However, pathways for carbon metabolism by these bacteria are poorly known. We are addressing this question by analyzing the lipid biomarkers and their isotope signatures in environments where the epsilon Proteobacteria are likely predominant. Solid materials were collected from hydrothermal vents in the East Pacific Rise and at the Guaymas Basin in the Gulf of California. Fatty acids extracted from these samples are dominated by 16:0 (27-41%), 18:0 (16-48%), 18:1 (11-42%), 16:1 (7-12%), and 14:0 (5-28%). In addition, 15:0 and anteiso-15:0 are significantly present (2-3%) in samples from the Guaymas Basin. The isotopic compositions of these fatty acids range from -15.0\\permil to -33.1\\permil with the most positive values occurring only in monounsaturated fatty acids (16:1 and 18:1). We are currently unable to assign these biomarkers to any of the epsilon Proteobacteria because biomarkers are poorly known for these organisms isolated from the vents. However, no polyunsaturated fatty acids were detected in these samples, which are consistent with the absence of vent animals at the sampling sites. Signature biomarkers of 20:1 and cy21:0, which are characteristic of the thermophilic chemolithoautotrophs such as Aquificales, are also absent in these samples. These results imply that the deeply branched Aquificales species do not constitute the major microbial community in these vent environments. The large range of molecular isotopic compositions suggests that these lipids are synthesized from various carbon sources with different isotopic compositions or through different biosynthetic pathways, or both. We are currently measuring the isotopic compositions of the total organic carbon in the bulk samples and will determine the fractionations between lipid biomarkers and the total organic carbon

Pathways for implementing REDD+. Experiences from carbon markets and communities

Energy Technology Data Exchange (ETDEWEB)

Zhu, X.; Ravnkilde Moeller, L.; Lopez, T. De; Romero, M.Z.

2011-07-01

This issue of Carbon Market Perspectives on 'Pathways for implementing REDD+: Experience from carbon markets and communities' discusses the role of carbon markets in scaling up investments for REDD+ in developing countries. Nine articles authored by experienced negotiators on REDD+, carbon market actors, project developers and other leading experts share experiences and make suggestions on the key elements of a future international REDD+ regime: Architecture and underlying principles, measuring, reporting and verification (MRV), private-sector involvement, the rights of indigenous people and local communities, biodiversity conservation and environmental integrity. The articles are grouped under three main topics: the lessons of existing REDD+ projects; the future REDD+ regime and the role of carbon markets; and experiences and ideas about the involvement of indigenous people and local communities. (LN)

Managing carbon regulatory risk in utility resource planning: Current practices in the Western United States

International Nuclear Information System (INIS)

Barbose, Galen; Wiser, Ryan; Phadke, Amol; Goldman, Charles

2008-01-01

Concerns about global climate change have substantially increased the likelihood that future policy will seek to minimize carbon dioxide emissions. As such, even today, electric utilities are making resource planning and investment decisions that consider the possible implications of these future carbon regulations. In this article, we examine the manner in which utilities assess the financial risks associated with future carbon regulations within their long-term resource plans. We base our analysis on a review of the most recent resource plans filed by 15 electric utilities in the Western United States. Virtually all of these utilities made some effort to quantitatively evaluate the potential cost of future carbon regulations when analyzing alternate supply- and demand-side resource options for meeting customer load. Even without federal climate regulation in the US, the prospect of that regulation is already having an impact on utility decision-making and resource choices. That said, the methods and assumptions used by utilities to analyze carbon regulatory risk, and the impact of that analysis on their choice of a particular resource strategy, vary considerably, revealing a number of opportunities for analytic improvement. Though our review focuses on a subset of US electric utilities, this work holds implications for all electric utilities and energy policymakers who are seeking to minimize the compliance costs associated with future carbon regulations

CO2 Reduction Catalyzed by Nitrogenase: Pathways to Formate, Carbon Monoxide, and Methane.

Science.gov (United States)

Khadka, Nimesh; Dean, Dennis R; Smith, Dayle; Hoffman, Brian M; Raugei, Simone; Seefeldt, Lance C

2016-09-06

The reduction of N2 to NH3 by Mo-dependent nitrogenase at its active-site metal cluster FeMo-cofactor utilizes reductive elimination of Fe-bound hydrides with obligatory loss of H2 to activate the enzyme for binding/reduction of N2. Earlier work showed that wild-type nitrogenase and a nitrogenase with amino acid substitutions in the MoFe protein near FeMo-cofactor can catalytically reduce CO2 by two or eight electrons/protons to carbon monoxide (CO) and methane (CH4) at low rates. Here, it is demonstrated that nitrogenase preferentially reduces CO2 by two electrons/protons to formate (HCOO(-)) at rates >10 times higher than rates of CO2 reduction to CO and CH4. Quantum mechanical calculations on the doubly reduced FeMo-cofactor with a Fe-bound hydride and S-bound proton (E2(2H) state) favor a direct reaction of CO2 with the hydride ("direct hydride transfer" reaction pathway), with facile hydride transfer to CO2 yielding formate. In contrast, a significant barrier is observed for reaction of Fe-bound CO2 with the hydride ("associative" reaction pathway), which leads to CO and CH4. Remarkably, in the direct hydride transfer pathway, the Fe-H behaves as a hydridic hydrogen, whereas in the associative pathway it acts as a protic hydrogen. MoFe proteins with amino acid substitutions near FeMo-cofactor (α-70(Val→Ala), α-195(His→Gln)) are found to significantly alter the distribution of products between formate and CO/CH4.

An optimization model for carbon capture & storage/utilization vs. carbon trading: A case study of fossil-fired power plants in Turkey.

Science.gov (United States)

Ağralı, Semra; Üçtuğ, Fehmi Görkem; Türkmen, Burçin Atılgan

2018-06-01

We consider fossil-fired power plants that operate in an environment where a cap and trade system is in operation. These plants need to choose between carbon capture and storage (CCS), carbon capture and utilization (CCU), or carbon trading in order to obey emissions limits enforced by the government. We develop a mixed-integer programming model that decides on the capacities of carbon capture units, if it is optimal to install them, the transportation network that needs to be built for transporting the carbon captured, and the locations of storage sites, if they are decided to be built. Main restrictions on the system are the minimum and maximum capacities of the different parts of the pipeline network, the amount of carbon that can be sold to companies for utilization, and the capacities on the storage sites. Under these restrictions, the model aims to minimize the net present value of the sum of the costs associated with installation and operation of the carbon capture unit and the transportation of carbon, the storage cost in case of CCS, the cost (or revenue) that results from the emissions trading system, and finally the negative revenue of selling the carbon to other entities for utilization. We implement the model on General Algebraic Modeling System (GAMS) by using data associated with two coal-fired power plants located in different regions of Turkey. We choose enhanced oil recovery (EOR) as the process in which carbon would be utilized. The results show that CCU is preferable to CCS as long as there is sufficient demand in the EOR market. The distance between the location of emission and location of utilization/storage, and the capacity limits on the pipes are an important factor in deciding between carbon capture and carbon trading. At carbon prices over $15/ton, carbon capture becomes preferable to carbon trading. These results show that as far as Turkey is concerned, CCU should be prioritized as a means of reducing nation-wide carbon emissions in an

Functional group diversity is key to Southern Ocean benthic carbon pathways.

Directory of Open Access Journals (Sweden)

David K A Barnes

Full Text Available High latitude benthos are globally important in terms of accumulation and storage of ocean carbon, and the feedback this is likely to have on regional warming. Understanding this ecosystem service is important but difficult because of complex taxonomic diversity, history and geography of benthic biomass. Using South Georgia as a model location (where the history and geography of benthic biology is relatively well studied we investigated whether the composition of functional groups were critical to benthic accumulation, immobilization and burial pathway to sequestration-and also aid their study through simplification of identification. We reclassified [1], [2] morphotype and carbon mass data to 13 functional groups, for each sample of 32 sites around the South Georgia continental shelf. We investigated the influence on carbon accumulation, immobilization and sequestration estimate by multiple factors including the compositions of functional groups. Functional groups showed high diversity within and between sites, and within and between habitat types. Carbon storage was not linked to a functional group in particular but accumulation and immobilization increased with the number of functional groups present and the presence of hard substrata. Functional groups were also important to carbon burial rate, which increased with the presence of mixed (hard and soft substrata. Functional groups showed high surrogacy for taxonomic composition and were useful for examining contrasting habitat categorization. Functional groups not only aid marine carbon storage investigation by reducing time and the need for team size and speciality, but also important to benthic carbon pathways per se. There is a distinct geography to seabed carbon storage; seabed boulder-fields are hotspots of carbon accumulation and immobilization, whilst the interface between such boulder-fields and sediments are key places for burial and sequestration.

Production of Odd-Carbon Dicarboxylic Acids in Escherichia coli Using an Engineered Biotin–Fatty Acid Biosynthetic Pathway

Energy Technology Data Exchange (ETDEWEB)

Haushalter, Robert W. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Bioscience Division; Phelan, Ryan M. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Bioscience Division; Hoh, Kristina M. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Bioscience Division; Su, Cindy [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Bioscience Division; Wang, George [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Bioscience Division; Baidoo, Edward E. K. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Bioscience Division; Keasling, Jay D. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Bioscience Division

2017-03-14

Dicarboxylic acids are commodity chemicals used in the production of plastics, polyesters, nylons, fragrances, and medications. Bio-based routes to dicarboxylic acids are gaining attention due to environmental concerns about petroleum-based production of these compounds. Some industrial applications require dicarboxylic acids with specific carbon chain lengths, including odd-carbon species. Biosynthetic pathways involving cytochrome P450-catalyzed oxidation of fatty acids in yeast and bacteria have been reported, but these systems produce almost exclusively even-carbon species. Here in this paper we report a novel pathway to odd-carbon dicarboxylic acids directly from glucose in Escherichia coli by employing an engineered pathway combining enzymes from biotin and fatty acid synthesis. Optimization of the pathway will lead to industrial strains for the production of valuable odd-carbon diacids.

Estimating environmental co-benefits of U.S. low-carbon pathways using an integrated assessment model with state-level resolution

Energy Technology Data Exchange (ETDEWEB)

Ou, Yang; Shi, Wenjing; Smith, Steven J.; Ledna, Catherine M.; West, J. Jason; Nolte, Christopher G.; Loughlin, Daniel H.

2018-04-01

There are many technological pathways that can lead to reduced carbon dioxide (CO₂) emissions. However, these pathways can have substantially different impacts on other environmental endpoints, such as air quality and energy-related water demand. This study uses an integrated assessment model with state-level resolution of the U.S. energy system to compare environmental impacts of alternative low-carbon pathways. One set of pathways emphasizes nuclear energy and carbon capture and storage (NUC/CCS), while another set emphasizes renewable energy (RE). These are compared with pathways in which all technologies are available. Air pollutant emissions, mortality costs attributable to particulate matter less than 2.5 microns in diameter (PM2.5), and energy-related water demands are evaluated for 50% and 80% CO₂ reduction targets in the U.S. in 2050. The RE low-carbon pathways require less water withdrawal and consumption than the NUC/CCS pathways because of the large cooling demands of nuclear power and CCS. However, the NUC/CCS low-carbon pathways produce greater health benefits, mainly because the NUC/CCS assumptions result in less primary PM2.5 emissions from residential wood combustion. Environmental co-benefits differ among states because of factors such as existing technology stock, resource availability, and environmental and energy policies. An important finding is that biomass in the building sector can offset some of the health co-benefits of the low-carbon pathways even though it plays only a minor role in reducing CO₂ emissions.

Formic Acid Manufacture: Carbon Dioxide Utilization Alternatives

Directory of Open Access Journals (Sweden)

Marta Rumayor

2018-06-01

Full Text Available Carbon dioxide (CO2 utilization alternatives for manufacturing formic acid (FA such as electrochemical reduction (ER or homogeneous catalysis of CO2 and H2 could be efficient options for developing more environmentally-friendly production alternatives to FA fossil-dependant production. However, these alternatives are currently found at different technological readiness levels (TRLs, and some remaining technical challenges need to be overcome to achieve at least carbon-even FA compared to the commercial process, especially ER of CO2, which is still farther from its industrial application. The main technical limitations inherited by FA production by ER are the low FA concentration achieved and the high overpotentials required, which involve high consumptions of energy (ER cell and steam (distillation. In this study, a comparison in terms of carbon footprints (CF using the Life Cycle Assessment (LCA tool was done to evaluate the potential technological challenges assuring the environmental competitiveness of the FA production by ER of CO2. The CF of the FA conventional production were used as a benchmark, as well as the CF of a simulated plant based on homogeneous catalysts of CO2 and H2 (found closer to be commercial. Renewable energy utilization as PV solar for the reaction is essential to achieve a carbon-even product; however, the CF benefits are still negligible due to the enormous contribution of the steam produced by natural gas (purification stage. Some ER reactor configurations, plus a recirculation mode, could achieve an even CF versus commercial process. It was demonstrated that the ER alternatives could lead to lower natural resources consumption (mainly, natural gas and heavy fuel oil compared to the commercial process, which is a noticeable advantage in environmental sustainability terms.

Algae Cultivation for Carbon Capture and Utilization Workshop Summary Report

Energy Technology Data Exchange (ETDEWEB)

None, None

2017-05-01

The Algae Cultivation for Carbon Capture and Utilization Workshop Summary Report summarizes a workshop hosted by the U.S. Department of Energy's Bioenergy Technologies Office on May 23–24, 2017, in Orlando, Florida. The event gathered stakeholder input through facilitated discussions focused on innovative technologies and business strategies for growing algae on waste carbon dioxide resources.

Pathways and bioenergetics of anaerobic carbon monoxide fermentation

NARCIS (Netherlands)

Diender, Martijn; Stams, Fons; Machado de Sousa, Diana

2015-01-01

Carbon monoxide can act as a substrate for different modes of fermentative anaerobic metabolism. The trait of utilizing CO is spread among a diverse group of microorganisms, including members of bacteria as well as archaea. Over the last decade this metabolism has gained interest due to the

Structure and Mechanism of PhnP, a Phosphodiesterase of the Carbon-Phosphorus Lyase Pathway

DEFF Research Database (Denmark)

He, Shu-Mei; Wathier, Matthew; Podzelinska, Kateryna

2011-01-01

PhnP is a phosphodiesterase that plays an important role within the bacterial carbon-phosphorus lyase (CP-lyase) pathway by recycling a "dead-end" intermediate, 5-phospho-α-d-ribosyl 1,2-cyclic phosphate, that is formed during organophosphonate catabolism. As a member of the metallo-β-lactamase s......PhnP is a phosphodiesterase that plays an important role within the bacterial carbon-phosphorus lyase (CP-lyase) pathway by recycling a "dead-end" intermediate, 5-phospho-α-d-ribosyl 1,2-cyclic phosphate, that is formed during organophosphonate catabolism. As a member of the metallo...

Effective utilization technology of carbon dioxide. CO sub 2 no yuko riyo gijutsu

Energy Technology Data Exchange (ETDEWEB)

Ibusuki, T. (National Research Inst. for pollution and Resources, Tsukuba (Japan))

1991-03-12

As carbon dioxide-related environmental measures, method was explained to chemically convert and utilize carbon dioxide. Synthesis is possible of methanol, carbon monoxide, different carbohydrates, etc. by catalytic hydrogenation of carbon dioxide, using hydrogen produced by the electrolysis of water. Task consists of heightening in both convertibility and selectivity, and abundant supply of low cost hydrogen. Methane, alcohol, etc. can be synthesized by electrochemical reducion of carbon dioxide. Because of effectively inserting multiple electron, discssion is being made of catalyst, intergrated with electrode, and electron transmitter. The photoelectrochemical reduction of carbon dioxide can be also made by utilizing photoelectric current, generated upon photoradiation on the semiconductive electrode. However, task consists of heightening in both efficiency and selectivity. Photochemical reduction of carbon dioxide, actually made by green plant, consists of oxidationlike decomposition of water and reduction of carbon dioxide. Both those reactions are skillfully separated by intermediation of very quick electron transmission system. Reduction is being studied with semiconductor, metallic colloid, enzyme, metallic complex and other various catalysts. 10 refs., 3 figs., 4 tabs.

Pathways of human development and carbon emissions embodied in trade

Science.gov (United States)

Steinberger, Julia K.; Timmons Roberts, J.; Peters, Glen P.; Baiocchi, Giovanni

2012-02-01

It has long been assumed that human development depends on economic growth, that national economic expansion in turn requires greater energy use and, therefore, increased greenhouse-gas emissions. These interdependences are the topic of current research. Scarcely explored, however, is the impact of international trade: although some nations develop socio-economically and import high-embodied-carbon products, it is likely that carbon-exporting countries gain significantly fewer benefits. Here, we use new consumption-based measures of national carbon emissions to explore how the relationship between human development and carbon changes when we adjust national emission rates for trade. Without such adjustment of emissions, some nations seem to be getting far better development `bang' for the carbon `buck' than others, who are showing scant gains for disproportionate shares of global emissions. Adjusting for the transfer of emissions through trade explains many of these outliers, but shows that further socio-economic benefits are accruing to carbon-importing rather than carbon-exporting countries. We also find that high life expectancies are compatible with low carbon emissions but high incomes are not. Finally, we see that, despite strong international trends, there is no deterministic industrial development trajectory: there is great diversity in pathways, and national histories do not necessarily follow the global trends.

Pathways of organic carbon oxidation in three continental margin sediments

DEFF Research Database (Denmark)

Canfield, Donald Eugene; Jørgensen, Bo Barker; Fossing, Henrik

1993-01-01

We have combined several different methodologies to quantify rates of organic carbon mineralization by the various electron acceptors in sediments from the coast of Denmark and Norway. Rates of NH4+ and Sigma CO2 liberation sediment incubations were used with O2 penetration depths to conclude...... that O2 respiration accounted for only between 3.6-17.4% of the total organic carbon oxidation. Dentrification was limited to a narrow zone just below the depth of O2 penetration, and was not a major carbon oxidation pathway. The processes of Fe reduction, Mn reduction and sulfate reduction dominated...... organic carbon mineralization, but their relative significance varied depending on the sediment. Where high concentrations of Mn-oxide were found (3-4 wt% Mn), only Mn reduction occurred. With lower Mn oxide concentrations more typical of coastal sediments, Fe reduction and sulfate reduction were most...

Diagenetic pathways in deposits of cool- and cold-water carbonate factories

Science.gov (United States)

Frank, T. D.; James, N. P.

2017-12-01

This investigation integrates sedimentological, petrographic, and geochemical observations from modern and ancient heterozoan carbonate deposits that formed at temperate to polar latitudes with the aim of evaluating diagenetic pathways characteristic of these systems. These factories operate under conditions distinct from those of photozoan counterparts. Lower temperatures, higher trophic resources, lower carbonate saturation states, and strong seasonality govern not only the nature of carbonate communities, but also how deposits translate into the rock record. In these settings, carbonate production is entirely biogenic, assemblages are of low diversity, and there are no significant calcareous phototrophs. Aragonitic taxa may be present in living communities, but allochems rapidly disappear via dissolution. Carbonate producers are not capable of building rigid frameworks, so their deposits accumulate as sands and gravels and are prone to winnowing and reworking. Low production rates lead to long seafloor residence times (1000s of years) for grains, which undergo physical reworking, dissolution, and repeated infestation by endolithic borers. Microborings remain empty, increasing grain susceptibility to disintegration. Intergranular cementation on the seafloor is rare and restricted to hardgrounds. Periods of subaerial exposure do not leave traces of meteoric alteration. Results show that the deposits of heterozoan carbonate factories tend enter the geologic record as taphonomic remnants, namely reworked, unconsolidated sands and gravels with low diagenetic potential. During burial, physical and chemical compaction produce limestones with tightly packed, grain-supported fabrics, often with grains in sutured contact. Significant cementation is associated with the deep burial realm. Results reveal a dramatically different diagenetic pathway than is typical for deposits of tropical photozoan factories, in which significant recrystallization and lithification occur on

NMR studies of stock process water and reaction pathways in hydrothermal carbonization of furfural residue

Directory of Open Access Journals (Sweden)

Fen Yue

2018-04-01

Full Text Available Hydrothermal carbonization (HTC is a valuable approach to convert furfural residue (FR into carbon material. The prepared biochars are usually characterized comprehensively, while the stock process water still remains to be studied in detail. Herein, a NMR study of the main components in stock process water generated at different HTC reaction conditions was reported. Various qualitative and quantitative NMR techniques (1H and 13C NMR, 1H–1H COSY and 1H13C HSQC etc. especially 1D selective gradient total correlation spectroscopy (TOCSY NMR were strategically applied in the analysis of HTC stock process water. Without separation and purification, it was demonstrated that the main detectable compounds are 5-hydroxymethylfurfural, formic acid, methanol, acetic acid, levulinic acid, glycerol, hydroxyacetone and acetaldehyde in this complicate mixture. Furthermore, the relationship between the concentration of major products and the reaction conditions (180–240 °C at 8 h, and 1–24 h at 240 °C was established. Finally, reasonable reaction pathways for hydrothermal conversion of FR were proposed based on this result and our previously obtained characteristics of biochars. The routine and challenging NMR methods utilized here would be an alternative other than HPLC or GC for biomass conversion research and can be extended to more studies. Keywords: NMR, Hydrothermal carbonization, Furfural residue, Stock process water

Production of carbon-13-labeled cadaverine by engineered Corynebacterium glutamicum using carbon-13-labeled methanol as co-substrate.

Science.gov (United States)

Leßmeier, Lennart; Pfeifenschneider, Johannes; Carnicer, Marc; Heux, Stephanie; Portais, Jean-Charles; Wendisch, Volker F

2015-12-01

Methanol, a one-carbon compound, can be utilized by a variety of bacteria and other organisms as carbon and energy source and is regarded as a promising substrate for biotechnological production. In this study, a strain of non-methylotrophic Corynebacterium glutamicum, which was able to produce the polyamide building block cadaverine as non-native product, was engineered for co-utilization of methanol. Expression of the gene encoding NAD+-dependent methanol dehydrogenase (Mdh) from the natural methylotroph Bacillus methanolicus increased methanol oxidation. Deletion of the endogenous aldehyde dehydrogenase genes ald and fadH prevented methanol oxidation to carbon dioxide and formaldehyde detoxification via the linear formaldehyde dissimilation pathway. Heterologous expression of genes for the key enzymes hexulose-6-phosphate synthase and 6-phospho-3-hexuloisomerase of the ribulose monophosphate (RuMP) pathway in this strain restored growth in the presence of methanol or formaldehyde, which suggested efficient formaldehyde detoxification involving RuMP key enzymes. While growth with methanol as sole carbon source was not observed, the fate of 13C-methanol added as co-substrate to sugars was followed and the isotopologue distribution indicated incorporation into central metabolites and in vivo activity of the RuMP pathway. In addition, 13C-label from methanol was traced to the secreted product cadaverine. Thus, this synthetic biology approach led to a C. glutamicum strain that converted the non-natural carbon substrate methanol at least partially to the non-native product cadaverine.

Reprogramming One-Carbon Metabolic Pathways To Decouple l-Serine Catabolism from Cell Growth in Corynebacterium glutamicum.

Science.gov (United States)

Zhang, Yun; Shang, Xiuling; Lai, Shujuan; Zhang, Yu; Hu, Qitiao; Chai, Xin; Wang, Bo; Liu, Shuwen; Wen, Tingyi

2018-02-16

l-Serine, the principal one-carbon source for DNA biosynthesis, is difficult for microorganisms to accumulate due to the coupling of l-serine catabolism and microbial growth. Here, we reprogrammed the one-carbon unit metabolic pathways in Corynebacterium glutamicum to decouple l-serine catabolism from cell growth. In silico model-based simulation showed a negative influence on glyA-encoding serine hydroxymethyltransferase flux with l-serine productivity. Attenuation of glyA transcription resulted in increased l-serine accumulation, and a decrease in purine pools, poor growth and longer cell shapes. The gcvTHP-encoded glycine cleavage (Gcv) system from Escherichia coli was introduced into C. glutamicum, allowing glycine-derived 13 CH 2 to be assimilated into intracellular purine synthesis, which resulted in an increased amount of one-carbon units. Gcv introduction not only restored cell viability and morphology but also increased l-serine accumulation. Moreover, comparative proteomic analysis indicated that abundance changes of the enzymes involved in one-carbon unit cycles might be responsible for maintaining one-carbon unit homeostasis. Reprogramming of the one-carbon metabolic pathways allowed cells to reach a comparable growth rate to accumulate 13.21 g/L l-serine by fed-batch fermentation in minimal medium. This novel strategy provides new insights into the regulation of cellular properties and essential metabolite accumulation by introducing an extrinsic pathway.

Transcriptome Analysis of Polyhydroxybutyrate Cycle Mutants Reveals Discrete Loci Connecting Nitrogen Utilization and Carbon Storage in Sinorhizobium meliloti.

Science.gov (United States)

D'Alessio, Maya; Nordeste, Ricardo; Doxey, Andrew C; Charles, Trevor C

2017-01-01

the cell. The impact of carbon storage on cellular metabolism would be reflected in global transcription patterns. By investigating the transcriptomic effects of genetically disrupting genes involved in the PHB carbon storage cycle, we revealed a relationship between intracellular carbon storage and nitrogen metabolism. This work demonstrates the utility of combining transcriptome sequencing with metabolic pathway mutations for identifying underlying gene regulatory mechanisms.

Evaluation of lead/carbon devices for utility applications : a study for the DOE Energy Storage Program.

Energy Technology Data Exchange (ETDEWEB)

Walmet, Paula S. (MeadWestvaco Corporation,North Charleston, SC)

2009-06-01

This report describes the results of a three-phase project that evaluated lead-based energy storage technologies for utility-scale applications and developed carbon materials to improve the performance of lead-based energy storage technologies. In Phase I, lead/carbon asymmetric capacitors were compared to other technologies that used the same or similar materials. At the end of Phase I (in 2005) it was found that lead/carbon asymmetric capacitors were not yet fully developed and optimized (cost/performance) to be a viable option for utility-scale applications. It was, however, determined that adding carbon to the negative electrode of a standard lead-acid battery showed promise for performance improvements that could be beneficial for use in utility-scale applications. In Phase II various carbon types were developed and evaluated in lead-acid batteries. Overall it was found that mesoporous activated carbon at low loadings and graphite at high loadings gave the best cycle performance in shallow PSoC cycling. Phase III studied cost/performance benefits for a specific utility application (frequency regulation) and the full details of this analysis are included as an appendix to this report.

Biocompatible yogurt carbon dots: evaluation of utilization for medical applications

Science.gov (United States)

Dinç, Saliha; Kara, Meryem; Demirel Kars, Meltem; Aykül, Fatmanur; Çiçekci, Hacer; Akkuş, Mehmet

2017-09-01

In this study, carbon dots (CDs) were produced from yogurt, a fermented milk product, via microwave-assisted process (800 W) in 30 min without using any additional chemical agents. Yogurt CDs had outstanding nitrogen and oxygen ratios. These dots were monodisperse and about 2 nm sized. The toxicological assessments of yogurt carbon dots in human cancer cells and normal epithelial cells and their fluorescence imaging in living cell system were carried out. Yogurt carbon dots had intense fluorescent signal under confocal microscopy and good fluorescence stability in living cell system. The resulting yogurt carbon dots exhibited high biocompatibility up to 7.1 mg/mL CD concentration which may find utilization in medical applications such as cellular tracking, imaging and drug delivery. Yogurt carbon dots have potential to be good diagnostic agents to visualize cancer cells which may be developed as a therapeutic carrier.

Estimating environmental co-benefits of U.S. low-carbon pathways using the GCAM-USA integrated assessment model

Data.gov (United States)

U.S. Environmental Protection Agency — There are many technological pathways that can lead to reduced carbon dioxide (CO2) emissions. However, these pathways can have substantially different impacts on...

Evaluation of energy efficiency of various biogas production and utilization pathways

International Nuclear Information System (INIS)

Poeschl, Martina; Ward, Shane; Owende, Philip

2010-01-01

The energy efficiency of different biogas systems, including single and co-digestion of multiple feedstock, different biogas utilization pathways, and waste-stream management strategies was evaluated. The input data were derived from assessment of existing biogas systems, present knowledge on anaerobic digestion process management and technologies for biogas system operating conditions in Germany. The energy balance was evaluated as Primary Energy Input to Output (PEIO) ratio, to assess the process energy efficiency, hence, the potential sustainability. Results indicate that the PEIO correspond to 10.5-64.0% and 34.1-55.0% for single feedstock digestion and feedstock co-digestion, respectively. Energy balance was assessed to be negative for feedstock transportation distances in excess of 22 km and 425 km for cattle manure and for Municipal Solid Waste, respectively, which defines the operational limits for respective feedstock transportation. Energy input was highly influenced by the characteristics of feedstock used. For example, agricultural waste, in most part, did not require pre-treatment. Energy crop feedstock required the respect cultivation energy inputs, and processing of industrial waste streams included energy-demanding pre-treatment processes to meet stipulated hygiene standards. Energy balance depended on biogas yield, the utilization efficiency, and energy value of intended fossil fuel substitution. For example, obtained results suggests that, whereas the upgrading of biogas to biomethane for injection into natural gas network potentially increased the primary energy input for biogas utilization by up to 100%; the energy efficiency of the biogas system improved by up to 65% when natural gas was substituted instead of electricity. It was also found that, system energy efficiency could be further enhanced by 5.1-6.1% through recovery of residual biogas from enclosed digestate storage units. Overall, this study provides bases for more detailed assessment

Carbon metabolic pathways in phototrophic bacteria and their broader evolutionary implications

Directory of Open Access Journals (Sweden)

Kuo-Hsiang eTang

2011-08-01

Full Text Available Photosynthesis is the biological process that converts solar energy to biomass, bio-products and biofuel. It is the only major natural solar energy storage mechanism on Earth. To satisfy the increased demand for sustainable energy sources and identify the mechanism of photosynthetic carbon assimilation, which is one of the bottlenecks in photosynthesis, it is essential to understand the process of solar energy storage and associated carbon metabolism in photosynthetic organisms. Researchers have employed physiological studies, microbiological chemistry, enzyme assays, genome sequencing, transcriptomics, and 13C-based metabolomics/fluxomics to investigate central carbon metabolism and enzymes that operate in phototrophs. In this report, we review diverse CO2 assimilation pathways, acetate assimilation, carbohydrate catabolism, the TCA cycle and some key and/or unconventional enzymes in central carbon metabolism of phototrophic microorganisms. We also discuss the reducing equivalent flow during photoautotrophic and photoheterotrophic growth, evolutionary links in the central carbon metabolic network, and correlations between photosynthetic and non-photosynthetic organisms. Considering the metabolic versatility in these fascinating and diverse photosynthetic bacteria, many essential questions in their central carbon metabolism still remain to be addressed.

Pathways and bioenergetics of anaerobic carbon monoxide fermentation.

OpenAIRE

Martijn eDiender; Alfons J.M. Stams; Alfons J.M. Stams; Diana Z. Sousa

2015-01-01

Carbon monoxide can act as a substrate for different modes of fermentative anaerobic metabolism. The trait of utilizing CO is spread among a diverse group of microorganisms, including members of bacteria as well as archaea. Over the last decade this metabolism has gained interest due to the potential of converting CO rich gas, such as synthesis gas, into bio-based products. Three main types of fermentative CO metabolism can be distinguished: hydrogenogenesis, methanogenesis and acetogenesis, ...

Evaluating The Performance of Asphalt Concrete Mixes by Utilizing Carbon Black as Asphalt Modifier

Directory of Open Access Journals (Sweden)

Aliaa Faleh Al.ani

2018-02-01

Full Text Available Carbon black produced from several factories in Iraq is expected to provide a reinforcing agent for asphalt paving materials. Carbon black has many characteristics that distinguish  it from conventional mineral fillers, as well as their different function in pavement mixtures. Theory and exercise advanced  in the inclusive utilize of carbon black as a reinforcing agent for rubber has led to concept of asphalt reinforcement. The very fine particles of micro filler added in different contents will be dispersed in asphalt cement improving the mechanical properties of asphalt concrete mixes. In this Four percentages rates were utilized; 0, 3, 6, and 9 percent adding to asphalt grade (60-70. Mixes of asphalt concrete were destined at their optimum asphalt content (OAC then experienced to assess their engineering characteristics that contain moisture of damage, permanent deformation, modulus of resilient and characteristics of fatigue. These characteristics have been assessed utilizing indirect tensile strength, uniaxial repeated loading and repeated flexural beam tests. Mixtures improved with carbon black were existed to have amended permanent deformation and fatigue characteristics, else exhibited high resilient modulus and lower moisture susceptibility. Result showed that a rate changed from 3 to 9 percent has shown an increase in resilient modulus for increment of carbon black and modulus of resilient for mixes with 9 percent carbon black was 1.4 times that for mixes with 0 percent carbon black. The altering of carbon black from a range (3-9 percent has modified the fatigue property of the asphalt concrete mixes as determined by flexural test, Significantly, to modify the asphalt concrete manner taken the  percent of carbon black 6, and to produce the mixes more durable , higher resistance to distresses by adding the local knowledge.

Response to Comment on "Dilution limits dissolved organic carbon utilization in the deep ocean"

KAUST Repository

Arrieta, J M; Mayol, E.; Hansman, R. L.; Herndl, G. J.; Dittmar, T.; Duarte, Carlos M.

2015-01-01

Our recent finding that dilution limits dissolved organic carbon (DOC) utilization in the deep ocean has been criticized based on the common misconception that lability equates to rapid and complete utilization. Even when considering

The kinetics of Scenedesmus obliquus microalgae growth utilizing carbon dioxide gas from biogas

International Nuclear Information System (INIS)

Thiansathit, Worrarat; Keener, Tim C.; Khang, Soon-Jai; Ratpukdi, Thunyalux; Hovichitr, Patcharee

2015-01-01

Microalgae Scenedesmus obliquus was cultured in a laboratory photobioreactor to determine the efficacy of using biogas as a carbon source for the microalgae's growth. The biogas contained ∼60% CH 4 and ∼40% CO 2 , and was derived from an anaerobic digester operating from animal wastes, and an anaerobic reactor utilizing high strength wastewater. The results showed that biogas is a viable carbon source for microalgae growth and that significant portions of the biogas' CO 2 can be utilized for algae growth, resulting in a biogas having a high concentration of methane. This paper develops the kinetic expressions for the algae's growth by assuming an autocatalytic reaction between carbon substrate and microalgae. The maximum specific growth rate and biomass productivity of S. obliquus were 0.56 d −1 and 0.145 g L −1 d −1 respectively. The biomass contained 51.8% carbon and higher heating value (HHV) was 22.9 MJ kg −1 . - Highlights: • Biogas is a viable carbon source for microalgae growth. • Biomass production rate and characteristics were assessed. • Scenedesmus obliquus can adjust to grow with high concentration of CO 2 in the carbon source

Carbon dioxide utilization in a microalga-based biorefinery: Efficiency of carbon removal and economic performance under carbon taxation.

Science.gov (United States)

Wiesberg, Igor Lapenda; Brigagão, George Victor; de Medeiros, José Luiz; de Queiroz Fernandes Araújo, Ofélia

2017-12-01

Coal-fired power plants are major stationary sources of carbon dioxide and environmental constraints demand technologies for abatement. Although Carbon Capture and Storage is the most mature route, it poses severe economic penalty to power generation. Alternatively, this penalty is potentially reduced by Carbon Capture and Utilization, which converts carbon dioxide to valuable products, monetizing it. This work evaluates a route consisting of carbon dioxide bio-capture by Chlorella pyrenoidosa and use of the resulting biomass as feedstock to a microalgae-based biorefinery; Carbon Capture and Storage route is evaluated as a reference technology. The integrated arrangement comprises: (a) carbon dioxide biocapture in a photobioreactor, (b) oil extraction from part of the produced biomass, (b) gasification of remaining biomass to obtain bio-syngas, and (c) conversion of bio-syngas to methanol. Calculation of capital and operational expenditures are estimated based on mass and energy balances obtained by process simulation for both routes (Carbon Capture and Storage and the biorefinery). Capital expenditure for the biorefinery is higher by a factor of 6.7, while operational expenditure is lower by a factor of 0.45 and revenues occur only for this route, with a ratio revenue/operational expenditure of 1.6. The photobioreactor is responsible for one fifth of the biorefinery capital expenditure, with footprint of about 1000 ha, posing the most significant barrier for technical and economic feasibility of the proposed biorefinery. The Biorefinery and Carbon Capture and Storage routes show carbon dioxide capture efficiency of 73% and 48%, respectively, with capture cost of 139$/t and 304$/t. Additionally, the biorefinery has superior performance in all evaluated metrics of environmental impacts. Copyright © 2017 Elsevier Ltd. All rights reserved.

Energy utilization and carbon dioxide emission in the fresh, paste, whole-peeled, diced, and juiced tomato production processes

International Nuclear Information System (INIS)

Karakaya, Ahmet; Ozilgen, Mustafa

2011-01-01

Energy utilization and carbon dioxide emission during the production of fresh, peeled, diced, and juiced tomatoes are calculated. The energy utilization for production of raw and packaging materials, transportation, and waste management are also considered. The energy utilization to produce one-ton retail packaged fresh tomatoes is calculated to be 2412.8 MJ, whereas when the tomatoes are converted into paste, the energy utilization increases almost twofold; processing the same amount into the peeled or diced-tomatoes increases the energy utilization seven times. In case of juice production, the increase is five times. The carbon dioxide emission is determined by the source of energy used and is 189.4 kg/t of fresh tomatoes in the case of retail packaging, and did not change considerably when made into paste. The carbon dioxide emission increased twofold with peeled or diced-tomatoes, and increased threefold when juiced. Chemical fertilizers and transportation made the highest contribution to energy utilization and CO 2 emission. The difference in energy utilization is determined mainly by water to dry solids ratio of the food and increases with the water content of the final product. Environmentally conscious consumers may prefer eating fresh tomatoes or alternatively tomato paste, to minimize carbon dioxide emission. -- Highlights: → Energy utilization for producing one-ton retail packaged fresh tomatoes was 2412.8 MJ → Energy utilization was 2 folds with paste, 7 times with peeled or diced-tomatoes, 5 times with juice. → Energy utilization increases with water content of the final product. → Transportation, packaging, evaporation and chemicals are the major energy consumers. → Carbon dioxide emission is determined by the source of energy.

Energy Utilization Evaluation of Carbon Performance in Public Projects by FAHP and Cloud Model

Directory of Open Access Journals (Sweden)

Lin Li

2016-07-01

Full Text Available With the low-carbon economy advocated all over the world, how to use energy reasonably and efficiently in public projects has become a major issue. It has brought many open questions, including which method is more reasonable in evaluating the energy utilization of carbon performance in public projects when the evaluation information is fuzzy; whether an indicator system can be constructed; and which indicators have more impact on carbon performance. This article aims to solve these problems. We propose a new carbon performance evaluation system for energy utilization based on project processes (design, construction, and operation. Fuzzy Analytic Hierarchy Process (FAHP is used to accumulate the indicator weights and cloud model is incorporated when the indicator value is fuzzy. Finally, we apply our indicator system to a case study of the Xiangjiang River project in China, which demonstrates the applicability and efficiency of our method.

Effect of electrode mass ratio on aging of activated carbon based supercapacitors utilizing organic electrolytes

Science.gov (United States)

Cericola, D.; Kötz, R.; Wokaun, A.

2011-03-01

The accelerated degradation of carbon based supercapacitors utilizing 1 M Et4NBF4 in acetonitrile and in propylene carbonate as electrolyte is investigated for a constant cell voltage of 3.5 V as a function of the positive over total electrode mass ratio. The degradation rate of the supercapacitor using acetonitrile as a solvent can be decreased by increasing the mass of the positive electrode. With a mass ratio (positive electrode mass/total electrode mass) of 0.65 the degradation rate is minimum. For the capacitor utilizing propylene carbonate as a solvent a similar effect was observed. The degradation rate was smallest for a mass ratio above 0.5.

Bioprospecting and evolving alternative xylose and arabinose pathway enzymes for use in Saccharomyces cerevisiae.

Science.gov (United States)

Lee, Sun-Mi; Jellison, Taylor; Alper, Hal S

2016-03-01

Bioprospecting is an effective way to find novel enzymes from strains with desirable phenotypes. Such bioprospecting has enabled organisms such as Saccharomyces cerevisiae to utilize nonnative pentose sugars. Yet, the efficiency of this pentose catabolism (especially for the case of arabinose) remains suboptimal. Thus, further pathway optimization or identification of novel, optimal pathways is needed. Previously, we identified a novel set of xylan catabolic pathway enzymes from a superior pentose-utilizing strain of Ustilago bevomyces. These enzymes were used to successfully engineer a xylan-utilizing S. cerevisiae through a blended approach of bioprospecting and evolutionary engineering. Here, we expanded this approach to xylose and arabinose catabolic pathway engineering and demonstrated that bioprospected xylose and arabinose catabolic pathways from U. bevomyces offer alternative choices for enabling efficient pentose catabolism in S. cerevisiae. By introducing a novel set of xylose catabolic genes from U. bevomyces, growth rates were improved up to 85 % over a set of traditional Scheffersomyces stipitis pathway genes. In addition, we suggested an alternative arabinose catabolic pathway which, after directed evolution and pathway engineering, enabled S. cerevisiae to grow on arabinose as a sole carbon source in minimal medium with growth rates upwards of 0.05 h(-1). This pathway represents the most efficient growth of yeast on pure arabinose minimal medium. These pathways provide great starting points for further strain development and demonstrate the utility of bioprospecting from U. bevomyces.

Quantification of the "global" authigenic carbonate δ13C value and implications for carbon cycling

Science.gov (United States)

Loyd, S. J.

2017-12-01

Relationships among early Earth ocean chemistry, atmospheric chemistry and the evolution/radiation of life have been inferred from carbon isotope compositions (δ13C) of marine carbonates. Under steady-state conditions, the isotope compositions of marine carbonates reflect both the amount and δ13C of carbon entering and leaving the oceans. Recently the traditional "two-output" (marine carbonate and organic matter) mass-balance equation has been modified to include a third, authigenic carbonate output term. However, the formation mechanisms of authigenic carbonates remain poorly understood, particularly from a global prospective. The utility of the new mass-balance approach will be limited until authigenic carbonates are better characterized (e.g., through δ13C analyses). Authigenic carbonates form largely as a result of 1) the respiratory degradation of organic matter (e.g., sulfate reduction), 2) the oxidation of methane and 3) the production of methane. These major reaction pathways can produce authigenic carbonates with highly variable δ13C compositions (δ13Cac). Spatiotemporal variation in the extent and prevalence of different pathways therefore exert a first order control on "global" δ13Cac. Here, values are compiled from new and existing data sets and a modern, global δ13Cac is calculated. When calculated as an average of all data or an averaged mean of individual sites, this value is very similar to normal marine sedimentary organic matter. This finding suggests that marine sediments behave largely as closed systems in the context of organic matter degradation and carbonate authigenesis. In addition, the lack of significant difference between authigenic and organic δ13C implies that these two mass-balance output terms can be considered collectively in more recent time intervals. It may be appropriate to separate these two terms when characterizing more ancient settings when redox characteristics promoted more reducing organic matter degradation

Carbon emissions associated with the procurement and utilization of forest harvest residues for energy, northern Minnesota, USA

Science.gov (United States)

Grant M. Domke; Dennis R. Becker; Anthony W. D' Amato; Alan R. Ek; Christopher W. Woodall

2012-01-01

Interest in the use of forest-derived biomass for energy has prompted comparisons to fossil fuels and led to controversy over the atmospheric consequences of its utilization. Much of the debate has centered on the carbon storage implications of utilizing whole trees for energy and the time frame necessary to offset the carbon emissions associated with fixed-life...

Energy utilization, carbon dioxide emission, and exergy loss in flavored yogurt production process

International Nuclear Information System (INIS)

Sorgüven, Esra; Özilgen, Mustafa

2012-01-01

This paper investigates the impact of food production processes on the environment in terms of energy and exergy utilization and carbon dioxide emission. There are three different energy utilization mechanisms in food production: Utilization of solar energy by plants to produce agricultural goods; feed consumption by herbivores to produce meat and milk; fossil fuel consumption by industrial processes to perform mixing, cooling, heating, etc. Production of strawberry-flavored yogurt, which involves these three mechanisms, is investigated here thermodynamically. Analysis starts with the cultivation of the ingredients and ends with the transfer of the final product to the market. The results show that 53% of the total exergy loss occurs during the milk production and 80% of the total work input is consumed during the plain yogurt making. The cumulative degree of perfection is 3.6% for the strawberry-flavored yogurt. This value can rise up to 4.6%, if renewable energy resources like hydropower and algal biodiesel are employed instead of fossil fuels. This paper points the direction for the development of new technology in food processing to decrease waste of energy and carbon dioxide accumulation in the atmosphere. -- Highlights: ► Energy and exergy utilization and carbon dioxide emission during strawberry-flavored yogurt production. ► Cumulative degree of perfection of strawberry-flavored yogurt is 3.6%. ► 53% of the total exergy loss occurs during the milk production. ► 80% of the total work input is consumed during the plain yogurt making.

Pathways of carbon oxidation in continental margin sediments off central Chile

DEFF Research Database (Denmark)

Thamdrup, B; Canfield, Donald Eugene

1996-01-01

Rates and oxidative pathways of organic carbon mineralization were determined in sediments at six stations on the shelf and slope off Concepcion Bay at 36.5 degrees S. The depth distribution of C oxidation rates was determined to 10 cm from accumulation of dissolved inorganic C in 1-5-d incubations...... the shelf was rich in NO3- and depleted of O2. Sediments at the four shelf stations were covered by mats of filamentous bacteria of the genera Thioploca and Beggiatoa. Carbon oxidation rates at these sites were extremely high near the sediment surface (>3 micromol cm-3 d-1) and decreased exponentially...... C oxidation between 0 and 10 cm. Carbon oxidation through Fe reduction contributed a further 12-29% of the depth-integrated rate, while the remainder of C oxidation was through SO4(2-) reduction. The depth distribution of Fe reduction agreed well with the distribution of poorly crystalline Fe oxides...

De Novo Biosynthesis of Glutarate via α-Keto Acid Carbon Chain Extension and Decarboxylation Pathway in Escherichia coli.

Science.gov (United States)

Wang, Jian; Wu, Yifei; Sun, Xinxiao; Yuan, Qipeng; Yan, Yajun

2017-10-20

Microbial based bioplastics are promising alternatives to petroleum based synthetic plastics due to their renewability and economic feasibility. Glutarate is one of the most potential building blocks for bioplastics. The recent biosynthetic routes for glutarate were mostly based on the l-lysine degradation pathway from Pseudomonas putida that required lysine either by feeding or lysine overproduction via genetic manipulations. Herein, we established a novel glutarate biosynthetic pathway by incorporation of a "+1" carbon chain extension pathway from α-ketoglutarate (α-KG) in combination with α-keto acid decarboxylation pathway in Escherichia coli. Introduction of homocitrate synthase (HCS), homoaconitase (HA) and homoisocitrate dehydrogenase (HICDH) from Saccharomyces cerevisiae into E. coli enabled "+1" carbon extension from α-KG to α-ketoadipate (α-KA), which was subsequently converted into glutarate by a promiscuous α-keto acid decarboxylase (KivD) and a succinate semialdehyde dehydrogenase (GabD). The recombinant E. coli coexpressing all five genes produced 0.3 g/L glutarate from glucose. To further improve the titers, α-KG was rechanneled into carbon chain extension pathway via the clustered regularly interspersed palindromic repeats system mediated interference (CRISPRi) of essential genes sucA and sucB in tricarboxylic acid (TCA) cycle. The final strain could produce 0.42 g/L glutarate, which was increased by 40% compared with the parental strain.

Carbon balance studies of glucose metabolism in rat cerebral cortical synaptosomes

Energy Technology Data Exchange (ETDEWEB)

Bauer, U; Brand, K

1982-07-01

Synaptosomes were isolated from rat cerebral cortex and incubated with (U-/sup 14/C)-, (1-/sup 14/C)- or (6-/sup 14/C)glucose. Glucose utilization and the metabolic partitioning of glucose carbon in products were determined by isotopic methods. From the data obtained a carbon balance was constructed, showing lactate to be the main product of glucose metabolism, followed by CO/sup 2/, amino acids and pyruvate. Measuring the release of /sup 14/CO/sup 2/ from glucose labelled in three different positions allowed the construction of a flow diagram of glucose carbon atoms in synaptosomes, which provides information about the contribution of the various pathways of glucose metabolism. Some 2% of glucose utilized was calculated to be degraded via the pentose phosphate pathway. Addition of chlorpromazine, imipramine or haloperidol at concentrations of 10(-5) M reduced glucose utilisation by 30% without changing the distribution pattern of radioactivity in the various products.

Utilization of corn cob biochar in a direct carbon fuel cell

Science.gov (United States)

Yu, Jinshuai; Zhao, Yicheng; Li, Yongdan

2014-12-01

Biochar obtained from the pyrolysis of corn cob is used as the fuel of a direct carbon fuel cell (DCFC) employing a composite electrolyte composed of a samarium doped ceria (SDC) and a eutectic carbonate phase. An anode layer made of NiO and SDC is utilized to suppress the cathode corrosion by the molten carbonate and improves the whole cell stability. The anode off-gas of the fuel cell is analyzed with a gas chromatograph. The effect of working temperature on the cell resistance and power output is examined. The maximum power output achieves 185 mW cm-2 at a current density of 340 mA cm-2 and 750 °C. An anode reaction scheme including the Boudouard reaction is proposed.

Utilization of Ethanolamine as Carbon Dioxide Absorber For

OpenAIRE

Yusuf, Asdiana Irma; Zakir, Muhammad; Maming, Maming

2015-01-01

Utilization of ethanolamine as carbon dioxide absober for estimating of coral age from langkai island via LSC (Liquid Scintillation Counting) method has been done. Focus is to analyze coral reefs taken from Langkai island surface which is relatively far from the influence of human activities. Chemical preparation was carried out by using a mixture of NaOH with H2O2 30% followed by a mixture of HClO4 with H2O2 30%, and finally with HCl solution to produce a clean sample with 8.6% weight reduct...

Hyperthermophilic Archaeon Thermococcus kodakarensis Utilizes a Four-Step Pathway for NAD+ Salvage through Nicotinamide Deamination.

Science.gov (United States)

Hachisuka, Shin-Ichi; Sato, Takaaki; Atomi, Haruyuki

2018-06-01

Many organisms possess pathways that regenerate NAD + from its degradation products, and two pathways are known to salvage NAD + from nicotinamide (Nm). One is a four-step pathway that proceeds through deamination of Nm to nicotinic acid (Na) by Nm deamidase and phosphoribosylation to nicotinic acid mononucleotide (NaMN), followed by adenylylation and amidation. Another is a two-step pathway that does not involve deamination and directly proceeds with the phosphoribosylation of Nm to nicotinamide mononucleotide (NMN), followed by adenylylation. Judging from genome sequence data, the hyperthermophilic archaeon Thermococcus kodakarensis is supposed to utilize the four-step pathway, but the fact that the adenylyltransferase encoded by TK0067 recognizes both NMN and NaMN also raises the possibility of a two-step salvage mechanism. Here, we examined the substrate specificity of the recombinant TK1676 protein, annotated as nicotinic acid phosphoribosyltransferase. The TK1676 protein displayed significant activity toward Na and phosphoribosyl pyrophosphate (PRPP) and only trace activity with Nm and PRPP. We further performed genetic analyses on TK0218 (quinolinic acid phosphoribosyltransferase) and TK1650 (Nm deamidase), involved in de novo biosynthesis and four-step salvage of NAD + , respectively. The ΔTK0218 mutant cells displayed growth defects in a minimal synthetic medium, but growth was fully restored with the addition of Na or Nm. The ΔTK0218 ΔTK1650 mutant cells did not display growth in the minimal medium, and growth was restored with the addition of Na but not Nm. The enzymatic and genetic analyses strongly suggest that NAD + salvage in T. kodakarensis requires deamination of Nm and proceeds through the four-step pathway. IMPORTANCE Hyperthermophiles must constantly deal with increased degradation rates of their biomolecules due to their high growth temperatures. Here, we identified the pathway that regenerates NAD + from nicotinamide (Nm) in the

Overcoming Barriers to Successfully Commercializing Carbon Dioxide Utilization

International Nuclear Information System (INIS)

Kant, Marvin

2017-01-01

The successful transition to a low-carbon economy hinges on innovative solutions and collaborative action on a global scale. Sustainable entrepreneurship is thereby recognized as a key driver in the creation and transformation of ecologically and socially sustainable economic systems. The purpose of this article is to contribute to this topic by understanding commercialization barriers for strong sustainability-oriented new technology ventures and to derive recommendations to overcome them. A qualitative multilevel approach is applied to identify barriers and drivers within the internal dynamic capabilities of the organization and within the organization’s external stakeholders. A model of barriers has been developed based on semi-structured interviews with new carbon dioxide utilization ventures and associated industry players in Canada, the USA, and the European Economic Area. Resulting recommendations to facilitate the (re-)design of a dedicated support system are proposed on four levels: (a) actors, (b) resources, (c) institutional settings, and (d) the coordination of the support system.

Overcoming Barriers to Successfully Commercializing Carbon Dioxide Utilization

Energy Technology Data Exchange (ETDEWEB)

Kant, Marvin, E-mail: marvin.kant@tu-berlin.de [Department of Entrepreneurship and Innovation Management, Technische Universität Berlin, Berlin (Germany)

2017-09-13

The successful transition to a low-carbon economy hinges on innovative solutions and collaborative action on a global scale. Sustainable entrepreneurship is thereby recognized as a key driver in the creation and transformation of ecologically and socially sustainable economic systems. The purpose of this article is to contribute to this topic by understanding commercialization barriers for strong sustainability-oriented new technology ventures and to derive recommendations to overcome them. A qualitative multilevel approach is applied to identify barriers and drivers within the internal dynamic capabilities of the organization and within the organization’s external stakeholders. A model of barriers has been developed based on semi-structured interviews with new carbon dioxide utilization ventures and associated industry players in Canada, the USA, and the European Economic Area. Resulting recommendations to facilitate the (re-)design of a dedicated support system are proposed on four levels: (a) actors, (b) resources, (c) institutional settings, and (d) the coordination of the support system.

Overcoming Barriers to Successfully Commercializing Carbon Dioxide Utilization

Directory of Open Access Journals (Sweden)

Marvin Kant

2017-09-01

Full Text Available The successful transition to a low-carbon economy hinges on innovative solutions and collaborative action on a global scale. Sustainable entrepreneurship is thereby recognized as a key driver in the creation and transformation of ecologically and socially sustainable economic systems. The purpose of this article is to contribute to this topic by understanding commercialization barriers for strong sustainability-oriented new technology ventures and to derive recommendations to overcome them. A qualitative multilevel approach is applied to identify barriers and drivers within the internal dynamic capabilities of the organization and within the organization’s external stakeholders. A model of barriers has been developed based on semi-structured interviews with new carbon dioxide utilization ventures and associated industry players in Canada, the USA, and the European Economic Area. Resulting recommendations to facilitate the (re-design of a dedicated support system are proposed on four levels: (a actors, (b resources, (c institutional settings, and (d the coordination of the support system.

Least cost pathways to a low carbon electricity system for Australia: impacts of transmission augmentation and extension

Science.gov (United States)

Dargaville, R. J.

2016-12-01

Designing the pathway to a low carbon energy system is complex, requiring consideration of the variable nature of renewables at the hourly timescale, emission intensity and ramp rate constraints of dispatchable technologies (both fossil and renewable) and transmission and distribution network limitations. In this work, an optimization framework taking into account these considerations has been applied to find the lowest cost ways to reduce carbon emissions by either 80% or 100% in 2050 while keeping the system operating reliably along the way. Technologies included are existing and advanced coal and gas technologies (with and without carbon capture and storage), rooftop PV, utility scale PV, concentrating solar thermal, hydro with and without pumped storage, bioenergy, and nuclear. In this study we also also the optimisation to increase transmission capacity along existing lines, and to extend key trunk lines into currently unserved areas. These augementations and extensions come at a cost. The otpimisation chooses these options when the benefits of accessing high quality renewable energy resources outweights the costs. Results show that for the 80% emission reduction case, there is limited need for transmission capacity increase, and that the existing grid copes well with the increased flows due to conversion to distrubuted renewable energy resources. However, in the 100% case the increased reliance on renewables means that signficant transmission augmentation is beneficial to the overall cost. This strongly suggests that it is important to understand the long term emission target early so that infrastructure investments can be optimised.

C1-Pathways in Methyloversatilis universalis FAM5: Genome Wide Gene Expression and Mutagenesis Studies

Directory of Open Access Journals (Sweden)

Nathan M. Good

2015-04-01

Full Text Available Methyloversatilis universalis FAM5 utilizes single carbon compounds such as methanol or methylamine as a sole source of carbon and energy. Expression profiling reveals distinct sets of genes altered during growth on methylamine vs methanol. As expected, all genes for the N-methylglutamate pathway were induced during growth on methylamine. Among other functions responding to the aminated source of C1-carbon, are a heme-containing amine dehydrogenase (Qhp, a distant homologue of formaldehyde activating enzyme (Fae3, molybdenum-containing formate dehydrogenase, ferredoxin reductase, a set of homologues to urea/ammonium transporters and amino-acid permeases. Mutants lacking one of the functional subunits of the amine dehydrogenase (ΔqhpA or Δfae3 showed no growth defect on C1-compounds. M. universalis FAM5 strains with a lesion in the H4-folate pathway were not able to use any C1-compound, methanol or methylamine. Genes essential for C1-assimilation (the serine cycle and glyoxylate shunt and H4MTP-pathway for formaldehyde oxidation showed similar levels of expression on both C1-carbon sources. M. universalis FAM5 possesses three homologs of the formaldehyde activating enzyme, a key enzyme of the H4MTP-pathway. Strains lacking the canonical Fae (fae1 lost the ability to grow on both C1-compounds. However, upon incubation on methylamine the fae1-mutant produced revertants (Δfae1R, which regained the ability to grow on methylamine. Double and triple mutants (Δfae1RΔfae3, or Δfae1RΔfae2 or Δfae1RΔfae2Δfae3 constructed in the revertant strain background showed growth similar to the Δfae1R phenotype. The metabolic pathways for utilization of methanol and methylamine in Methyloversatilis universalis FAM5 are reconstructed based on these gene expression and phenotypic data.

Compound-Specific Carbon, Nitrogen, and Hydrogen Isotopic Ratios for Amino Acids in CM and CR Chondrites and their use in Evaluating Potential Formation Pathways

Science.gov (United States)

Elsila, Jamie E.; Charnley, Steven B.; Burton, Aaron S.; Glavin, Daniel P.; Dworkin, Jason P.

2012-01-01

Stable hydrogen, carbon, and nitrogen isotopic ratios (oD, 013C, and olSN) of organic compounds can revcal information about their origin and formation pathways. Several formation mechanisms and environments have been postulated for the amino acids detected in carbonaceous chondrites. As each proposed mechanism utilizes different precursor molecules, the isotopic signatures of the resulting amino acids may indicate the most likely of these pathways. We have applied gas chromatography with mass spectrometry and combustion isotope ratio mass spectrometry to measure the compound-specific C, N, and H stable isotopic ratios of amino acids from seven CM and CR carbonaceous chondrites: CM1I2 Allan Hills (ALH) 83100, CM2 Murchison, CM2 Lewis Cliff (LEW) 90500, CM2 Lonewolf Nunataks (LON) 94101, CRZ Graves Nunataks (GRA) 95229, CRZ Elephant Moraine (EET) 92042, and CR3 Queen Alexandra Range (QUE) 99177. We compare the isotopic compositions of amino acids in these meteorites with predictions of expected isotopic enrichments from potential formation pathways. We observe trends of decreasing ODC and increasing oD with increasing carbon number in the aH, (l-NH2 amino acids that correspond to predictions made for formation via Streckercyanohydrin synthesis. We also observe light ODC signatures for -alanine, which may indicate either formation via Michael addition or via a pathway that forms primarily small, straight-chain, amine-terminal amino acids (n-ro-amino acids). Higher deuterium enrichments are observed in amethyl amino acids, indicating formation of these amino acids or their precursors in cold interstellar or nebular environments. Finally, individual amino acids are more enriched in deuterium in CR chondrites than CM chondrites, reflecting different parent-body chemistry.

Response to Comment on "Dilution limits dissolved organic carbon utilization in the deep ocean"

KAUST Repository

Arrieta, Jesus

2015-12-18

Our recent finding that dilution limits dissolved organic carbon (DOC) utilization in the deep ocean has been criticized based on the common misconception that lability equates to rapid and complete utilization. Even when considering the redefinition of recalcitrant DOC recently proposed by Jiao et al., the dilution hypothesis best explains our experimental observations.

Active pore space utilization in nanoporous carbon-based supercapacitors: Effects of conductivity and pore accessibility

Science.gov (United States)

Seredych, Mykola; Koscinski, Mikolaj; Sliwinska-Bartkowiak, Malgorzata; Bandosz, Teresa J.

2012-12-01

Composites of commercial graphene and nanoporous sodium-salt-polymer-derived carbons were prepared with 5 or 20 weight% graphene. The materials were characterized using the adsorption of nitrogen, SEM/EDX, thermal analysis, Raman spectroscopy and potentiometric titration. The samples' conductivity was also measured. The performance of the carbon composites in energy storage was linked to their porosity and electronic conductivity. The small pores (<0.7) were found as very active for double layer capacitance. It was demonstrated that when double layer capacitance is a predominant mechanism of charge storage, the degree of the pore space utilization for that storage can be increased by increasing the conductivity of the carbons. That active pore space utilization is defined as gravimetric capacitance per unit pore volume in pores smaller than 0.7 nm. Its magnitude is affected by conductivity of the carbon materials. The functional groups, besides pseudocapacitive contribution, increased the wettability and thus the degree of the pore space utilization. Graphene phase, owing to its conductivity, also took part in an insitu increase of the small pore accessibility and thus the capacitance of the composites via enhancing an electron transfer to small pores and thus imposing the reduction of groups blocking the pores for electrolyte ions.

Controlled deposition and utilization of carbon on Ni-YSZ anodes of SOFCs operating on dry methane

International Nuclear Information System (INIS)

Jiao, Yong; Zhang, Liqin; An, Wenting; Zhou, Wei; Sha, Yujing; Shao, Zongping; Bai, Jianping; Li, Si-Dian

2016-01-01

Solid oxide fuel cells (SOFCs) are promising power-generation systems to utilize methane or methane-based fuels with a high energy efficiency and low environmental impact. A successive multi-stage process is performed to explore the operation of cells using dry methane or the deposited carbon from methane decomposition as fuel. Stable operation can be maintained by optimizing the fuel supply and current density parameters. An electrochemical impedance analysis suggests that the partial oxidization of Ni can occur at anodes when the carbon fuel is consumed. The stability of cells operated on pure methane is investigated in three operating modes. The cell can run in a comparatively stable state with continuous power output in an intermittent methane supply mode, where the deposition and utilization of carbon is controlled by balancing the fuel supply and consumption. The increase in the polarization resistance of the cell might originate from the small amount of NiO and residual carbon at the anode, which can be removed via an oxidation-and-reduction maintenance process. Based on the above strategy, this work provides an alternative operating mode to improve the stability of direct methane SOFCs and demonstrates the feasibility of its application. - Highlights: • A new strategy to control the deposition and utilization of carbon was developed. • A stable fuel cell operation was obtained with an intermittent fuel supply mode. • Polarization resistance increased due to small amount of NiO and residual carbon.

Kenya's Climate Change Action Plan. Low Carbon Climate Resilient Development Pathway

Energy Technology Data Exchange (ETDEWEB)

Murphy, D.; Sawyer, D.; Stiebert, S.; McFatridge, S. [International Institute for Sustainable Development IISD, Winnipeg, Manitoba (Canada); Wuertenberger, L.; Van Tilburg, X.; Hekkenberg, M. [Energy research Centre of the Netherlands ECN, Policy Studies, Amsterdam (Netherlands); Owino, T.; Battye, W. [ClimateCare, Nairobi (Kenya); Mutia, T. [Regional Institute for Social Enterprise Kenya RISE, Nairobi (Kenya); Olum, P. [Climate Change Consultant (Kenya)

2012-12-15

Kenya Vision 2030 - the long-term development blueprint for the country - aims to transform Kenya into 'a newly industrialising, middle-income country providing a high quality of life to all its citizens in a clean and secure environment'. A low carbon climate resilient development pathway, as set out in this Climate Change Action Plan, can help meet Vision 2030 goals through actions that address both sustainable development and climate change. This pathway can also help the Government achieve the Millennium Development Goals and other internationally agreed development goals without compromising the environment and its natural resources. As Kenya realizes its development aspirations, there will be gains and risks. A growing population and economy with migration to cities will mean increases in greenhouse gas (GHG) emissions. Resulting environmental and social conditions, including increased competition over resources, could intensify vulnerability to climate risks. Transitioning to a low carbon climate resilient development pathway can address future risks thereby improving Kenya's ability to prosper under a changing climate while reducing the emissions intensity of a growing economy. Moving forward on the 2010 National Climate Change Response Strategy will help Kenya transition to a low carbon climate resilient development pathway that puts people and livelihoods at the forefront. The strategy recognized the importance of climate change and development, and this Climate Change Action Plan is the logical next step. A yearlong multistakeholder participatory process involving the public sector, private sector and civil society resulted in this Action Plan that identifies priority climate change actions for Kenya for the short, medium and long term. The Government of Kenya takes climate change and its impact on development seriously. Climate change is considered a crosscutting issue that will be mainstreamed in the planning process both at the national

A generic methodology for the design of sustainable carbon dioxide utilization processes using superstructure optimization

DEFF Research Database (Denmark)

Frauzem, Rebecca; Gani, Rafiqul

, including as an extractive agent or raw material. Chemical conversion, an important element of utilization, involves the use of carbon dioxide as a reactant in the production of chemical compounds [2]. However, for feasible implementation, a systematic methodology is needed for the design of the utilization......, especially chemical conversion, processes. To achieve this, a generic methodology has been developed, which adopts a three-stage approach consisting in (i) process synthesis, (ii) process design, and (iii) innovative and sustainable design [3]. This methodology, with the individual steps and associated...... methods and tools, has been developed and applied to carbon dioxide utilization networks. This work will focus on the first stage, process synthesis, of this three-stage methodology; process synthesis is important in determining the appropriate processing route to produce products from a selection...

Pathways and bioenergetics of anaerobic carbon monoxide fermentation.

Directory of Open Access Journals (Sweden)

Martijn eDiender

2015-11-01

Full Text Available Carbon monoxide can act as a substrate for different modes of fermentative anaerobic metabolism. The trait of utilizing CO is spread among a diverse group of microorganisms, including members of bacteria as well as archaea. Over the last decade this metabolism has gained interest due to the potential of converting CO rich gas, such as synthesis gas, into bio-based products. Three main types of fermentative CO metabolism can be distinguished: hydrogenogenesis, methanogenesis and acetogenesis, generating hydrogen, methane and acetate, respectively. Here, we review the current knowledge on these three variants of microbial CO metabolism with an emphasis on the potential enzymatic routes and bio-energetics involved.

Pathways and Bioenergetics of Anaerobic Carbon Monoxide Fermentation.

Science.gov (United States)

Diender, Martijn; Stams, Alfons J M; Sousa, Diana Z

2015-01-01

Carbon monoxide can act as a substrate for different modes of fermentative anaerobic metabolism. The trait of utilizing CO is spread among a diverse group of microorganisms, including members of bacteria as well as archaea. Over the last decade this metabolism has gained interest due to the potential of converting CO-rich gas, such as synthesis gas, into bio-based products. Three main types of fermentative CO metabolism can be distinguished: hydrogenogenesis, methanogenesis, and acetogenesis, generating hydrogen, methane and acetate, respectively. Here, we review the current knowledge on these three variants of microbial CO metabolism with an emphasis on the potential enzymatic routes and bio-energetics involved.

LPA, HGF, and EGF utilize distinct combinations of signaling pathways to promote migration and invasion of MDA-MB-231 breast carcinoma cells

International Nuclear Information System (INIS)

Harrison, Susan MW; Knifley, Teresa; Chen, Min; O’Connor, Kathleen L

2013-01-01

Various pathways impinge on the actin-myosin pathway to facilitate cell migration and invasion including members of the Rho family of small GTPases and MAPK. However, the signaling components that are considered important for these processes vary substantially within the literature with certain pathways being favored. These distinctions in signaling pathways utilized are often attributed to differences in cell type or physiological conditions; however, these attributes have not been systematically assessed. To address this question, we analyzed the migration and invasion of MDA-MB-231 breast carcinoma cell line in response to various stimuli including lysophosphatidic acid (LPA), hepatocyte growth factor (HGF) and epidermal growth factor (EGF) and determined the involvement of select signaling pathways that impact myosin light chain phosphorylation. LPA, a potent stimulator of the Rho-ROCK pathway, surprisingly did not require the Rho-ROCK pathway to stimulate migration but instead utilized Rac and MAPK. In contrast, LPA-stimulated invasion required Rho, Rac, and MAPK. Of these three major pathways, EGF-stimulated MDA-MB-231 migration and invasion required Rho; however, Rac was essential only for invasion and MAPK was dispensable for migration. HGF signaling, interestingly, utilized the same pathways for migration and invasion, requiring Rho but not Rac signaling. Notably, the dependency of HGF-stimulated migration and invasion as well as EGF-stimulated invasion on MAPK was subject to the inhibitors used. As expected, myosin light chain kinase (MLCK), a convergence point for MAPK and Rho family GTPase signaling, was required for all six conditions. These observations suggest that, while multiple signaling pathways contribute to cancer cell motility, not all pathways operate under all conditions. Thus, our study highlights the plasticity of cancer cells to adapt to multiple migratory cues

Investigating Pathways of Nutrient and Energy Flows Through Aquatic Food Webs Using Stable Isotopes of Carbon and Nitrogen

Energy Technology Data Exchange (ETDEWEB)

Hadwen, W. L.; Bunn, S. E. [Australian Rivers Institute, Griffith School of Environment, Griffith University, Nathan Campus, Brisbane, Queensland (Australia)

2013-05-15

Carbon and nitrogen stable isotopes can provide valuable insights into pathways of nutrient and energy flows in aquatic ecosystems. Carbon stable isotopes are principally used to trace pathways of organic matter transfer through aquatic food webs, particularly with regard to identifying the dominant sources of nutrition for aquatic biota. Stable isotopes of carbon have been widely used to answer one of the most pressing questions in aquatic food web ecology - to what degree do in-stream (autochthonous) and riparian (allochthonous) sources of energy fuel riverine food webs? In conjunction with carbon stable isotopes, nitrogen stable isotopes have been used to determine the trophic position of consumers and to identify the number of trophic levels in aquatic food webs. More recently, stable nitrogen isotopes have been recommended as indicators of anthropogenic disturbances. Specifically, agricultural land uses and/or sewage effluent discharge have been shown to significantly increase {delta}{sup 15}N signatures in primary producers and higher order consumers in freshwater, estuarine and marine environments. Together, carbon and nitrogen stable isotopes can be used to examine natural food web functions as well as the degree to which human modifications to catchments and aquatic environments can influence aquatic ecosystem function. (author)

Carbon isotopes of dissolved inorganic carbon reflect utilization of different carbon sources by microbial communities in two limestone aquifer assemblages

Directory of Open Access Journals (Sweden)

M. E. Nowak

2017-08-01

Full Text Available Isotopes of dissolved inorganic carbon (DIC are used to indicate both transit times and biogeochemical evolution of groundwaters. These signals can be complicated in carbonate aquifers, as both abiotic (i.e., carbonate equilibria and biotic factors influence the δ13C and 14C of DIC. We applied a novel graphical method for tracking changes in the δ13C and 14C of DIC in two distinct aquifer complexes identified in the Hainich Critical Zone Exploratory (CZE, a platform to study how water transport links surface and shallow groundwaters in limestone and marlstone rocks in central Germany. For more quantitative estimates of contributions of different biotic and abiotic carbon sources to the DIC pool, we used the NETPATH geochemical modeling program, which accounts for changes in dissolved ions in addition to C isotopes. Although water residence times in the Hainich CZE aquifers based on hydrogeology are relatively short (years or less, DIC isotopes in the shallow, mostly anoxic, aquifer assemblage (HTU were depleted in 14C compared to a deeper, oxic, aquifer complex (HTL. Carbon isotopes and chemical changes in the deeper HTL wells could be explained by interaction of recharge waters equilibrated with post-bomb 14C sources with carbonates. However, oxygen depletion and δ13C and 14C values of DIC below those expected from the processes of carbonate equilibrium alone indicate considerably different biogeochemical evolution of waters in the upper aquifer assemblage (HTU wells. Changes in 14C and 13C in the upper aquifer complexes result from a number of biotic and abiotic processes, including oxidation of 14C-depleted OM derived from recycled microbial carbon and sedimentary organic matter as well as water–rock interactions. The microbial pathways inferred from DIC isotope shifts and changes in water chemistry in the HTU wells were supported by comparison with in situ microbial community structure based on 16S rRNA analyses. Our findings

Preliminary assessment of a method utilizing carbon dioxide and steelmaking slags to produce precipitated calcium carbonate

International Nuclear Information System (INIS)

Eloneva, Sanni; Said, Arshe; Fogelholm, Carl-Johan; Zevenhoven, Ron

2012-01-01

Highlights: ► An NH 4 -salt-based method utilizes CO 2 and steelmaking slags to produce pure CaCO 3 . ► It was determined if its economic potential warrants moving forward. ► Despite small solvent losses, the method was found to have economical potential. ► The method has significant CO 2 emissions reduction potential. ► Scaling up the reactor will allow for a more detailed design for the process. -- Abstract: One of the options that can contribute to the reduction of carbon dioxide emissions for climate change mitigation is the so-called CO 2 sequestration by mineral carbonation, or CO 2 mineral sequestration. Steel manufacturing could benefit from this option by utilizing its own by-products, i.e. steelmaking slags to combine with CO 2 . We have recently studied a method, where aqueous solution of ammonium salt (e.g. ammonium acetate, ammonium nitrate and ammonium chloride) is used to extract calcium selectively from the steel converter slag, followed by precipitation of pure calcium carbonate by bubbling CO 2 through the produced solution. The ammonium salt solution is recovered and re-used. The purpose of this research was to determine if the economic potential of the method warrants moving forward to large-scale application. Despite the small solvent losses, the method was found to have economical potential. In addition, it has significant CO 2 emission reduction potential as well. Scaling up the reactor from the small laboratory scale will allow more detailed design for the process to be made followed by a full economical evaluation including all of the important operational and capital investment costs.

Systematic framework for carbon dioxide capture and utilization processes to reduce the global carbon dioxide emissions

DEFF Research Database (Denmark)

Frauzem, Rebecca; Plaza, Cristina Calvera; Gani, Rafiqul

information-data on various carbon dioxide emission sources and available capture-utilization technologies; the model and solution libraries [2]; and the generic 3-stage approach for determining more sustainable solutions [3] through superstructure (processing networks) based optimization – adopted for global...... need to provide, amongst other options: useful data from in-house databases on carbon dioxide emission sources; mathematical models from a library of process-property models; numerical solvers from library of implemented solvers; and, work-flows and data-flows for different benefit scenarios...... to be investigated. It is useful to start by developing a prototype framework and then augmenting its application range by increasing the contents of its databases, libraries and work-flows and data-flows. The objective is to present such a prototype framework with its implemented database containing collected...

Dilution limits dissolved organic carbon utilization in the deep ocean

KAUST Repository

Arrieta, Jesus

2015-03-19

Oceanic dissolved organic carbon (DOC) is the second largest reservoir of organic carbon in the biosphere. About 72% of the global DOC inventory is stored in deep oceanic layers for years to centuries, supporting the current view that it consists of materials resistant to microbial degradation. An alternative hypothesis is that deep-water DOC consists of many different, intrinsically labile compounds at concentrations too low to compensate for the metabolic costs associated to their utilization. Here, we present experimental evidence showing that low concentrations rather than recalcitrance preclude consumption of a substantial fraction of DOC, leading to slow microbial growth in the deep ocean. These findings demonstrate an alternative mechanism for the long-term storage of labile DOC in the deep ocean, which has been hitherto largely ignored. © 2015, American Association for the Advancement of Science. All rights reserved.

Dilution limits dissolved organic carbon utilization in the deep ocean

KAUST Repository

Arrieta, J M; Mayol, Eva; Hansman, Roberta L.; Herndl, Gerhard J.; Dittmar, Thorsten; Duarte, Carlos M.

2015-01-01

Oceanic dissolved organic carbon (DOC) is the second largest reservoir of organic carbon in the biosphere. About 72% of the global DOC inventory is stored in deep oceanic layers for years to centuries, supporting the current view that it consists of materials resistant to microbial degradation. An alternative hypothesis is that deep-water DOC consists of many different, intrinsically labile compounds at concentrations too low to compensate for the metabolic costs associated to their utilization. Here, we present experimental evidence showing that low concentrations rather than recalcitrance preclude consumption of a substantial fraction of DOC, leading to slow microbial growth in the deep ocean. These findings demonstrate an alternative mechanism for the long-term storage of labile DOC in the deep ocean, which has been hitherto largely ignored. © 2015, American Association for the Advancement of Science. All rights reserved.

Carbon dioxide utilization via carbonate-promoted C-H carboxylation.

Science.gov (United States)

Banerjee, Aanindeeta; Dick, Graham R; Yoshino, Tatsuhiko; Kanan, Matthew W

2016-03-10

Using carbon dioxide (CO2) as a feedstock for commodity synthesis is an attractive means of reducing greenhouse gas emissions and a possible stepping-stone towards renewable synthetic fuels. A major impediment to synthesizing compounds from CO2 is the difficulty of forming carbon-carbon (C-C) bonds efficiently: although CO2 reacts readily with carbon-centred nucleophiles, generating these intermediates requires high-energy reagents (such as highly reducing metals or strong organic bases), carbon-heteroatom bonds or relatively acidic carbon-hydrogen (C-H) bonds. These requirements negate the environmental benefit of using CO2 as a substrate and limit the chemistry to low-volume targets. Here we show that intermediate-temperature (200 to 350 degrees Celsius) molten salts containing caesium or potassium cations enable carbonate ions (CO3(2-)) to deprotonate very weakly acidic C-H bonds (pKa > 40), generating carbon-centred nucleophiles that react with CO2 to form carboxylates. To illustrate a potential application, we use C-H carboxylation followed by protonation to convert 2-furoic acid into furan-2,5-dicarboxylic acid (FDCA)--a highly desirable bio-based feedstock with numerous applications, including the synthesis of polyethylene furandicarboxylate (PEF), which is a potential large-scale substitute for petroleum-derived polyethylene terephthalate (PET). Since 2-furoic acid can readily be made from lignocellulose, CO3(2-)-promoted C-H carboxylation thus reveals a way to transform inedible biomass and CO2 into a valuable feedstock chemical. Our results provide a new strategy for using CO2 in the synthesis of multi-carbon compounds.

Distribution of δ-aminolevulinic acid biosynthetic pathways among phototrophic and related bacteria

International Nuclear Information System (INIS)

Avissar, Y.J.; Beale, S.I.; Ormerod, J.G.

1989-01-01

Two biosynthetic pathways are known for the universal tetrapyrrole precursor, δ-aminolevulinic acid (ALA): condensation of glycine and succinyl-CoA to form ALA with the loss of C-1 of glycine as CO 2 , and conversion of the intact carbon skeleton of glutamate to ALA in a process requiring tRNA Glu , ATP, Mg 2+ , NADPH, and pyridoxal phosphate. The distribution of the two ALA biosynthetic pathways among various bacterial genera was determined, using cell-free extracts obtained from representative organisms. Evidence for the operation of the glutamate pathway was obtained by the measurement of RNase-sensitive label incorporation from glutamate into ALA using 3,4-[ 3 H]glutamate and 1-[ 14 C]glutamate as substrate. The glycine pathway was indicated by RNase-insensitive incorporation of level from 2-[ 14 C]glycine into ALA. The distribution of the two pathways among the bacteria tested was in general agreement with their previously phylogenetic relationships and clearly indicates that the glutamate pathway is the more ancient process, whereas the glycine pathway probably evolved much later. The glutamate pathway is the more widely utilized one among bacteria, while the glycine pathway is apparently limited to the α subgroup of purple bacteria (including Rhodobacter, Rhodospirillum, and Rhizobium). E. coli was found ALA via the glutamate pathway. The ALA-requiring hemA mutant of E. coli was determined to lack the dehydrogenase activity that utilizes glutamyl-tRNA as a substrate

Microbial carbon pump and its significance for carbon sequestration in soils

Science.gov (United States)

Liang, Chao

2017-04-01

Studies of the decomposition, transformation and stabilization of soil organic carbon have dramatically increased in recent years due to growing interest in studying the global carbon cycle as it pertains to climate change. While it is readily accepted that the magnitude of the organic carbon reservoir in soils depends upon microbial involvement because soil carbon dynamics are ultimately the consequence of microbial growth and activity, it remains largely unknown how these microbe-mediated processes lead to soil carbon stabilization. Here, two pathways, ex vivo modification and in vivo turnover, were defined to jointly explain soil carbon dynamics driven by microbial catabolism and/or anabolism. Accordingly, a conceptual framework consisting of the raised concept of the soil "microbial carbon pump" (MCP) was demonstrated to describe how microbes act as an active player in soil carbon storage. The hypothesis is that the long-term microbial assimilation process may facilitate the formation of a set of organic compounds that are stabilized (whether via protection by physical interactions or a reduction in activation energy due to chemical composition), ultimately leading to the sequestration of microbial-derived carbon in soils. The need for increased efforts was proposed to seek to inspire new studies that utilize the soil MCP as a conceptual guideline for improving mechanistic understandings of the contributions of soil carbon dynamics to the responses of the terrestrial carbon cycle under global change.

Evolution and Adaptation of Phytoplankton Photosynthetic Pathways to perturbations of the geological carbon system

Science.gov (United States)

Rickaby, R. E.; Young, J. N.; Hermoso, M.; Heureux, A.; McCLelland, H.; Lee, R.; Eason Hubbard, M.

2012-12-01

The ocean and atmosphere carbon system has varied greatly over geological history both in response to initial evolutionary innovation, and as a driver of adaptive change. Here we establish that positive selection in Rubisco, the most abundant enzyme on the Earth responsible for all photosynthetic carbon fixation, occurred early in Earth's history, and basal to the radiation of the modern marine algal groups. Our signals of positive selection appear to be triggered by changing intracellular concentrations of carbon dioxide (CO2) due to the emergence of carbon concentrating mechanisms between 1.56 and 0.41 Ba in response to declining atmospheric CO2 . We contend that, at least in terms of carbon, phytoplankton generally were well poised to manage subsequent abrupt carbon cycle perturbations. The physiological pathways for optimising carbon acquisition across a wide range of ambient carbon dioxide concentrations had already been established and were genetically widespread across open ocean phytoplankton groups. We will further investigate some case studies from the Mesozoic and Cenozoic abrupt carbon cycle excursions using isotopic tools to probe the community photosynthetic response and demonstrate the flexibility of phytoplankton photosynthesis in the face of major perturbations. In particular, an unprecedented resolution record across the Toarcian (Early Jurassic) carbon isotope excursion in the Paris Basin reveals a selection and evolution towards a community reliant solely on diffusive carbon dioxide supply for photosynthesis at the height of the excursion at 1500-2500 ppm CO2. The continued flourishing of the phytoplankton biological pump throughout this excursion was able to remove the excess carbon injected into the water column in less than 45 kyrs.

Carbon Dioxide Utilization by the Five-Membered Ring Products of Cyclometalation Reactions

Science.gov (United States)

Omae, Iwao

2016-01-01

In carbon dioxide utilization by cyclometalated five-membered ring products, the following compounds are used in four types of applications: 1. 2-Phenylpyrazole iridium compounds, pincer phosphine iridium compounds and 2-phenylimidazoline iridium compounds are used as catalysts for both formic acid production from CO2 and H2, and hydrogen production from the formic acid. This formic acid can be a useful agent for H2 production and storage for fuel cell electric vehicles. 2. Other chemicals, e.g., dimethyl carbonate, methane, methanol and CO, are produced with dimethylaminomethylphenyltin compounds, pincer phosphine iridium compounds, pincer phosphine nickel compound and ruthenium carbene compound or 2-phenylpyridine iridium compounds, and phenylbenzothiazole iridium compounds as the catalysts for the reactions with CO2. 3. The five-membered ring intermediates of cyclometalation reactions with the conventional substrates react with carbon dioxide to afford their many types of carboxylic acid derivatives. 4. Carbon dioxide is easily immobilized at room temperature with immobilizing agents such as pincer phosphine nickel compounds, pincer phosphine palladium compounds, pincer N,N-dimethylaminomethyltin compounds and tris(2-pyridylthio)methane zinc compounds. PMID:28503084

pathways to deep decarbonization - 2014 report

International Nuclear Information System (INIS)

Sachs, Jeffrey; Guerin, Emmanuel; Mas, Carl; Schmidt-Traub, Guido; Tubiana, Laurence; Waisman, Henri; Colombier, Michel; Bulger, Claire; Sulakshana, Elana; Zhang, Kathy; Barthelemy, Pierre; Spinazze, Lena; Pharabod, Ivan

2014-09-01

The Deep Decarbonization Pathways Project (DDPP) is a collaborative initiative to understand and show how individual countries can transition to a low-carbon economy and how the world can meet the internationally agreed target of limiting the increase in global mean surface temperature to less than 2 degrees Celsius (deg. C). Achieving the 2 deg. C limit will require that global net emissions of greenhouse gases (GHG) approach zero by the second half of the century. This will require a profound transformation of energy systems by mid-century through steep declines in carbon intensity in all sectors of the economy, a transition we call 'deep decarbonization.' Successfully transition to a low-carbon economy will require unprecedented global cooperation, including a global cooperative effort to accelerate the development and diffusion of some key low carbon technologies. As underscored throughout this report, the results of the DDPP analyses remain preliminary and incomplete. The DDPP proceeds in two phases. This 2014 report describes the DDPP's approach to deep decarbonization at the country level and presents preliminary findings on technically feasible pathways to deep decarbonization, utilizing technology assumptions and timelines provided by the DDPP Secretariat. At this stage we have not yet considered the economic and social costs and benefits of deep decarbonization, which will be the topic for the next report. The DDPP is issuing this 2014 report to the UN Secretary-General Ban Ki-moon in support of the Climate Leaders' Summit at the United Nations on September 23, 2014. This 2014 report by the Deep Decarbonization Pathway Project (DDPP) summarizes preliminary findings of the technical pathways developed by the DDPP Country Research Partners with the objective of achieving emission reductions consistent with limiting global warming to less than 2 deg. C., without, at this stage, consideration of economic and social costs and benefits. The DDPP is a knowledge

Metabolic engineering of a glycerol-oxidative pathway in Lactobacillus panis PM1 for utilization of bioethanol thin stillage: potential to produce platform chemicals from glycerol.

Science.gov (United States)

Kang, Tae Sun; Korber, Darren R; Tanaka, Takuji

2014-12-01

Lactobacillus panis PM1 has the ability to produce 1,3-propanediol (1,3-PDO) from thin stillage (TS), which is the major waste material after bioethanol production, and is therefore of significance. However, the fact that L. panis PM1 cannot use glycerol as a sole carbon source presents a considerable problem in terms of utilization of this strain in a wide range of industrial applications. Accordingly, L. panis PM1 was genetically engineered to directly utilize TS as a fermentable substrate for the production of valuable platform chemicals without the need for exogenous nutrient supplementation (e.g., sugars and nitrogen sources). An artificial glycerol-oxidative pathway, comprised of glycerol facilitator, glycerol kinase, glycerol 3-phosphate dehydrogenase, triosephosphate isomerase, and NADPH-dependent aldehyde reductase genes of Escherichia coli, was introduced into L. panis PM1 in order to directly utilize glycerol for the production of energy for growth and value-added chemicals. A pH 6.5 culture converted glycerol to mainly lactic acid (85.43 mM), whereas a significant amount of 1,3-propanediol (59.96 mM) was formed at pH 7.5. Regardless of the pH, ethanol (82.16 to 83.22 mM) was produced from TS fermentations, confirming that the artificial pathway metabolized glycerol for energy production and converted it into lactic acid or 1,3-PDO and ethanol in a pH-dependent manner. This study demonstrates the cost-effective conversion of TS to value-added chemicals by the engineered PM1 strain cultured under industrial conditions. Thus, application of this strain or these research findings can contribute to reduced costs of bioethanol production. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Carbon Capture and Utilization in the Industrial Sector.

Science.gov (United States)

Psarras, Peter C; Comello, Stephen; Bains, Praveen; Charoensawadpong, Panunya; Reichelstein, Stefan; Wilcox, Jennifer

2017-10-03

The fabrication and manufacturing processes of industrial commodities such as iron, glass, and cement are carbon-intensive, accounting for 23% of global CO 2 emissions. As a climate mitigation strategy, CO 2 capture from flue gases of industrial processes-much like that of the power sector-has not experienced wide adoption given its high associated costs. However, some industrial processes with relatively high CO 2 flue concentration may be viable candidates to cost-competitively supply CO 2 for utilization purposes (e.g., polymer manufacturing, etc.). This work develops a methodology that determines the levelized cost ($/tCO 2 ) of separating, compressing, and transporting carbon dioxide. A top-down model determines the cost of separating and compressing CO 2 across 18 industrial processes. Further, the study calculates the cost of transporting CO 2 via pipeline and tanker truck to appropriately paired sinks using a bottom-up cost model and geo-referencing approach. The results show that truck transportation is generally the low-cost alternative given the relatively small volumes (ca. 100 kt CO 2 /a). We apply our methodology to a regional case study in Pennsylvania, which shows steel and cement manufacturing paired to suitable sinks as having the lowest levelized cost of capture, compression, and transportation.

Scenario analysis of China's emissions pathways in the 21st century for low carbon transition

International Nuclear Information System (INIS)

Wang Tao; Watson, Jim

2010-01-01

China's growing demand for energy - and its dependence on coal - has seen its carbon emissions increase more than 50% since 2000. Within the debate about mitigating global climate change, there is mounting pressure for emerging economies like China to take more responsibility for reducing their carbon emissions within a post-2012 international climate change policy framework. For China, this leads to fundamental questions about how feasible it is for the country to shift away from its recent carbon intensive pattern of growth. This paper presents some general results of scenarios that have been developed to investigate how China might continue to develop within a cumulative carbon emissions budget. The results show how changes in the key sectors of the Chinese economy could enable China to follow four different low carbon development pathways, each of which complies with a cumulative emissions constraint. Each scenario reflects different priorities for governmental decision making, infrastructure investments and social preferences. Having compared the key features of each scenario, the paper concludes with some implications for Chinese government policy.

Pathways to a low-carbon economy for the UK with the macro-econometric E3MG model

International Nuclear Information System (INIS)

Dagoumas, A.S.; Barker, T.S.

2010-01-01

This paper examines different carbon pathways for achieving deep CO 2 reduction targets for the UK using a macro-econometric hybrid model E3MG, which stands for Energy-Economy-Environment Model at the Global level. The E3MG, with the UK as one of its regions, combines a top-down approach for modeling the global economy and for estimating the aggregate and disaggregate energy demand and a bottom-up approach (Energy Technology subModel, ETM) for simulating the power sector, which then provides feedback to the energy demand equations and the whole economy. The ETM submodel uses a probabilistic approach and historical data for estimating the penetration levels of the different technologies, considering their economic, technical and environmental characteristics. Three pathway scenarios (CFH, CLC and CAM) simulate the CO 2 reduction by 40%, 60% and 80% by 2050 compared to 1990 levels respectively and are compared with a reference scenario (REF), with no reduction target. The targets are modeled as the UK contribution to an international mitigation effort, such as achieving the G8 reduction targets, which is a more realistic political framework for the UK to move towards deep reductions rather than moving alone. This paper aims to provide modeling evidence that deep reduction targets can be met through different carbon pathways while also assessing the macroeconomic effects of the pathways on GDP and investment.

Glyphosate Utilization as the Source of Carbon: Isolation and Identification of new Bacteria

Directory of Open Access Journals (Sweden)

M. Mohsen Nourouzi

2011-01-01

Full Text Available Mixed bacteria from oil palm plantation soil (OPS were isolated to investigate their ability to utilize glyphosate as carbon source. Results showed that approximately all of the glyphosate was converted to aminomethyl-phosphonic acid (AMPA (99.5%. It is worthy to note that mixed bacteria were able to degrade only 2% of AMPA to further metabolites. Two bacterial strains i.e. Stenotrophomonas maltophilia and Providencia alcalifaciens were obtained from enrichment culture. Bacterial isolates were cultured individually on glyphosate as a sole carbon source. It was observed that both isolates were able to convert glyphosate to AMPA.

Sustainable process design with process intensification - Development and implementation of a framework for sustainable carbon dioxide capture and utilization processes

DEFF Research Database (Denmark)

Frauzem, Rebecca

. The developed framework adopts a 3-stage approach for sustainable design, which is comprised of: (1) synthesis, (2) design, and (3) innovation. In the first stage, the optimal processing route is obtained from a network via a superstructure-based approach. This stage incorporates a structured database...... and are designed and simulated in detail: 1. Dimethyl ether from methanol via combined reforming 2. Dimethyl ether from methanol via direct hydrogenation 3. Dimethyl carbonate via ethylene carbonate and methanol from combined reforming 4. Dimethyl carbonate via ethylene carbonate and methanol from direct...... hydrogenation. Through the analysis of the processes, it can be seen that the methanol distillation and the dimethyl carbonate downstream separation contribute to largeamounts of the utility consumption and therefore costs. Therefore, the reductionof the utility consumption of the methanol distillation...

Microbial-induced remediation of Zn2+ pollution based on the capture and utilization of carbon dioxide

Directory of Open Access Journals (Sweden)

Qiwei Zhan

2016-01-01

Conclusions: The TG-DSC results showed that weight loss of the precipitates occurred around 253°C. The FTIR and TG-DSC results were in accord with the XRD and EDS results and proved again that the precipitates were basic zinc carbonate. This work thus demonstrates a new method for processing Zn2+ pollution based on the utilization of carbon dioxide.

An Integrative Approach to Energy Carbon and Redox Metabolism In Cyanobacterium Synechocystis

Energy Technology Data Exchange (ETDEWEB)

Dr. Ross Overbeek

2003-06-30

The main objectives for the first year were to produce a detailed metabolic reconstruction of synechocystis sp.pcc6803 especially in interrelated arrears of photosynthesis respiration and central carbon metabolism to support a more complete understanding and modeling of this organism. Additionally, IG, Inc. provided detailed bioinformatic analysis of selected functional systems related to carbon and energy generation and utilization, and of the corresponding pathways functional roles and individual genes to support wet lab experiments by collaborators.

Isolation and characterization of yeasts capable of efficient utilization of hemicellulosic hydrolyzate as the carbon source.

Science.gov (United States)

Cassa-Barbosa, L A; Procópio, R E L; Matos, I T S R; Filho, S A

2015-09-28

Few yeasts have shown the potential to efficiently utilize hemicellulosic hydrolyzate as the carbon source. In this study, microorganisms isolated from the Manaus region in Amazonas, Brazil, were characterized based on their utilization of the pentoses, xylose, and arabinose. The yeasts that showed a potential to assimilate these sugars were selected for the better utilization of lignocellulosic biomass. Two hundred and thirty seven colonies of unicellular microorganisms grown on hemicellulosic hydrolyzate, xylose, arabinose, and yeast nitrogen base selective medium were analyzed. Of these, 231 colonies were subjected to sugar assimilation tests. One hundred and twenty five of these were shown to utilize hydrolyzed hemicellulose, xylose, or arabinose as the carbon source for growth. The colonies that showed the best growth (N = 57) were selected, and their internal transcribed spacer-5.8S rDNA was sequenced. The sequenced strains formed four distinct groups in the phylogenetic tree, and showed a high percentage of similarity with Meyerozyma caribbica, Meyerozyma guilliermondii, Trichosporon mycotoxinivorans, Trichosporon loubieri, Pichia kudriavzevii, Candida lignohabitans, and Candida ethanolica. The discovery of these xylose-fermenting yeasts could attract widespread interest, as these can be used in the cost-effective production of liquid fuel from lignocellulosic materials.

Pentose pathway in human liver

International Nuclear Information System (INIS)

Magnusson, I.; Chandramouli, V.; Schumann, W.C.; Kumaran, K.; Wahren, J.; Landau, B.R.

1988-01-01

[1- 14 C]Ribose and [1- 14 C]glucose were given to normal subjects along with glucose loads (1 g per kg of body weight) after administration of diflunisal and acetaminophen, drugs that are excreted in urine as glucuronides. Distributions of 14 C were determined in the carbons of the excreted glucoronides and in the glucose from blood samples drawn from hepatic veins before and after glucagon administration. Eighty percent or more of the 14 C from [1- 14 C]ribose incorporated into the glucuronic acid moiety of the glucuronides was in carbons 1 and 3, with less than 8% in carbon 2. In glucuronic acid from glucuronide excreted when [2- 14 C]glucose was given, 3.5-8.1% of the 14 C was in carbon 1, 2.5-4.3% in carbon 3, and more than 70% in carbon 2. These distributions are in accord with the glucuronides sampling the glucose unit of the glucose 6-phosphate pool that is a component of the pentose pathway and is intermediate in glycogen formation. It is concluded that the glucuronic acid conjugates of the drugs can serve as a noninvasive means of sampling hepatic glucose 6-phosphate. In human liver, as in animal liver, the classical pentose pathway functions, not the L-type pathway, and only a small percentage of the glucose is metabolized via the pathway

Metabolism of Hydrocarbons in n-Alkane-Utilizing Anaerobic Bacteria.

Science.gov (United States)

Wilkes, Heinz; Buckel, Wolfgang; Golding, Bernard T; Rabus, Ralf

2016-01-01

The glycyl radical enzyme-catalyzed addition of n-alkanes to fumarate creates a C-C-bond between two concomitantly formed stereogenic carbon centers. The configurations of the two diastereoisomers of the product resulting from n-hexane activation by the n-alkane-utilizing denitrifying bacterium strain HxN1, i.e. (1-methylpentyl)succinate, were assigned as (2S,1'R) and (2R,1'R). Experiments with stereospecifically deuterated n-(2,5-2H2)hexanes revealed that exclusively the pro-S hydrogen atom is abstracted from C2 of the n-alkane by the enzyme and later transferred back to C3 of the alkylsuccinate formed. These results indicate that the alkylsuccinate-forming reaction proceeds with an inversion of configuration at the carbon atom (C2) of the n-alkane forming the new C-C-bond, and thus stereochemically resembles a SN2-type reaction. Therefore, the reaction may occur in a concerted manner, which may avoid the highly energetic hex-2-yl radical as an intermediate. The reaction is associated with a significant primary kinetic isotope effect (kH/kD ≥3) for hydrogen, indicating that the homolytic C-H-bond cleavage is involved in the first irreversible step of the reaction mechanism. The (1-methylalkyl)succinate synthases of n-alkane-utilizing anaerobic bacteria apparently have very broad substrate ranges enabling them to activate not only aliphatic but also alkyl-aromatic hydrocarbons. Thus, two denitrifiers and one sulfate reducer were shown to convert the nongrowth substrate toluene to benzylsuccinate and further to the dead-end product benzoyl-CoA. For this purpose, however, the modified β-oxidation pathway known from alkylbenzene-utilizing bacteria was not employed, but rather the pathway used for n-alkane degradation involving CoA ligation, carbon skeleton rearrangement and decarboxylation. Furthermore, various n-alkane- and alkylbenzene-utilizing denitrifiers and sulfate reducers were found to be capable of forming benzyl alcohols from diverse alkylbenzenes

Identification of Biodegradation Pathways in a Multi-Process Phytoremediation System (MPPS) Using Natural Abundance 14C Analysis of PLFA

Science.gov (United States)

Cowie, B. R.; Greenberg, B. M.; Slater, G. F.

2008-12-01

Optimizing remediation of petroleum-contaminated soils requires thorough understanding of the mechanisms and pathways involved in a proposed remediation system. In many engineered and natural attenuation systems, multiple degradation pathways may contribute to observed contaminant mass losses. In this study, biodegradation in the soil microbial community was identified as a major pathway for petroleum hydrocarbon removal in a Multi-Process Phytoremediation System (MPPS) using natural abundance 14C analysis of Phospholipid Fatty Acids (PLFA). In contaminated soils, PLFA were depleted in Δ14C to less than -800‰, directly demonstrating microbial uptake and utilization of petroleum derived carbon (Δ14C = -992‰) during bioremediation. Mass balance indicated that more than 80% of microbial carbon was derived from petroleum hydrocarbons and a maximum of 20% was produced from metabolism of modern carbon sources. In contrast, in a nearby uncontaminated control soil, the microbial community maintained a nearly modern 14C signature, suggesting preferential degradation of more labile, recent carbon. Mass balance using δ13C and Δ14C of soil CO2 demonstrated that mineralization of petroleum carbon contributed 60-65% of soil CO2 at the contaminated site. The remainder was derived from atmospheric (27-30%) and decomposition of non- petroleum natural organic carbon (5-10%). The clean control exhibited substantially lower CO2 concentrations that were derived from atmospheric (55%) and natural organic carbon (45%) sources. This study highlights the value of using multiple carbon isotopes to identify degradation pathways in petroleum- contaminated soils undergoing phytoremediation and the power of natural abundance 14C to detect petroleum metabolism in natural microbial communities.

Avoiding, transforming, transitioning: pathways to sustainable low carbon passenger transport in developing countries

DEFF Research Database (Denmark)

Meza, Maria Josefina Figueroa; Fulton, Lewis; Tiwari, Geetam

2013-01-01

This review examines conditions affecting road passenger transport in developing countries that can be instrumental to building a pathway for reducing carbon emissions while concurrently meeting sustainable development goals. By contrasting present and future status of these conditions a vision...... in motorized travel are also necessary from OECD countries; the focus there is given to what level of pricing and regulatory interventions could change behavior. The articulation of detailed visions can help clarify and prioritize areas where policy efforts can have great impact. Strong actions are necessary...

Nitrogen reduction pathways in estuarine sediments: Influences of organic carbon and sulfide

Science.gov (United States)

Plummer, Patrick; Tobias, Craig; Cady, David

2015-10-01

Potential rates of sediment denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA) were mapped across the entire Niantic River Estuary, CT, USA, at 100-200 m scale resolution consisting of 60 stations. On the estuary scale, denitrification accounted for ~ 90% of the nitrogen reduction, followed by DNRA and anammox. However, the relative importance of these reactions to each other was not evenly distributed through the estuary. A Nitrogen Retention Index (NIRI) was calculated from the rate data (DNRA/(denitrification + anammox)) as a metric to assess the relative amounts of reactive nitrogen being recycled versus retained in the sediments following reduction. The distribution of rates and accompanying sediment geochemical analytes suggested variable controls on specific reactions, and on the NIRI, depending on position in the estuary and that these controls were linked to organic carbon abundance, organic carbon source, and pore water sulfide concentration. The relationship between NIRI and organic carbon abundance was dependent on organic carbon source. Sulfide proved the single best predictor of NIRI, accounting for 44% of its observed variance throughout the whole estuary. We suggest that as a single metric, sulfide may have utility as a proxy for gauging the distribution of denitrification, anammox, and DNRA.

Photosynthetic carbon fixation pathways in Zostera marina and three Florida seagrasses

Energy Technology Data Exchange (ETDEWEB)

Beer, S.; Wetzel, R.G.

1982-06-01

The photosynthetic carbon fixation pathways of four seagrass species, Zostera marina L. from Alaska and Thalassia testudinum Banks ex Konig, Syringodium filiforme Kutz. and Halodule wrightii Aschers. from the Gulf of Mexico, were investigated with a /sup 14/C pulse-chase technique. All species were found to be principally of the C/sub 3/ type. However, Thalassia and Halodule had higher initial incorporation rates into organic acids than is typical for terrestrial C/sub 3/ plants. Of 11 seagrass species investigated thus far for C/sub 3/ or C/sub 4/ metabolism using this technique, 10 were found to be principally of the C/sub 3/ type while only one exhibited C/sub 4/ metabolism.

The carbon storage regulator (Csr) system exerts a nutrient-specific control over central metabolism in Escherichia coli strain Nissle 1917.

Science.gov (United States)

Revelles, Olga; Millard, Pierre; Nougayrède, Jean-Philippe; Dobrindt, Ulrich; Oswald, Eric; Létisse, Fabien; Portais, Jean-Charles

2013-01-01

The role of the post-transcriptional carbon storage regulator (Csr) system in nutrient utilization and in the control of the central metabolism in E. coli reference commensal strain Nissle 1917 was investigated. Analysis of the growth capabilities of mutants altered for various components of the Csr system (csrA51, csrB, csrC and csrD mutations) showed that only the protein CsrA - the key component of the system - exerts a marked role in carbon nutrition. Attenuation of CsrA activity in the csrA51 mutant affects the growth efficiency on a broad range of physiologically relevant carbon sources, including compounds utilized by the Entner-Doudoroff (ED) pathway. Detailed investigations of the metabolomes and fluxomes of mutants and wild-type cells grown on carbon sources representative of glycolysis and of the ED pathway (glucose and gluconate, respectively), revealed significant re-adjusting of central carbon metabolism for both compounds in the csrA51 mutant. However, the metabolic re-adjusting observed on gluconate was strikingly different from that observed on glucose, indicating a nutrient-specific control of metabolism by the Csr system.

Manganese Electrocatalysts with Bulky Bipyridine Ligands: Utilizing Lewis Acids To Promote Carbon Dioxide Reduction at Low Overpotentials.

Science.gov (United States)

Sampson, Matthew D; Kubiak, Clifford P

2016-02-03

Earth-abundant manganese bipyridine (bpy) complexes are well-established molecular electrocatalysts for proton-coupled carbon dioxide (CO2) reduction to carbon monoxide (CO). Recently, a bulky bipyridine ligand, 6,6'-dimesityl-2,2'-bipyridine (mesbpy), was utilized to significantly lower the potential necessary to access the doubly reduced states of these manganese catalysts by eliminating their ability to dimerize after one-electron reduction. Although this Mn mesbpy catalyst binds CO2 at very low potentials, reduction of a resulting Mn(I)-COOH complex at significantly more negative potentials is required to achieve fast catalytic rates. Without reduction of Mn(I)-COOH, catalysis occurs slowly via a alternate catalytic pathway-protonation of Mn(I)-COOH to form a cationic tetracarbonyl complex. We report the use of Lewis acids, specifically Mg(2+) cations, to significantly increase the rate of catalysis (by over 10-fold) at these low overpotentials (i.e., the same potential as CO2 binding). Reduction of CO2 occurs at one of the lowest overpotentials ever reported for molecular electrocatalysts (η = 0.3-0.45 V). With Mg(2+), catalysis proceeds via a reductive disproportionation reaction of 2CO2 + 2e(-) → CO and CO3(2-). Insights into the catalytic mechanism were gained by using variable concentration cyclic voltammetry, infrared spectroelectrochemistry, and bulk electrolysis studies. The catalytic Tafel behavior (log turnover frequency vs overpotential relationship) of [Mn(mesbpy)(CO)3(MeCN)](OTf) with added Mg(2+) is compared with those of other commonly studied CO2 reduction catalysts.

Technology roadmap study on carbon capture, utilization and storage in China

International Nuclear Information System (INIS)

Zhang, Xian; Fan, Jing-Li; Wei, Yi-Ming

2013-01-01

Carbon capture, utilization and storage (CCUS) technology will likely become an important approach to reduce carbon dioxide (CO 2 ) emissions and optimize the structure of energy consumption in China in the future. In order to provide guidance and recommendations for CCUS Research, Development and Demonstration in China, a high level stakeholder workshop was held in Chongqing in June 2011 to develop a technology roadmap for the development of CCUS technology. This roadmap outlines the overall vision to provide technically viable and economically affordable technological options to combat climate change and facilitate socio-economic development in China. Based on this vision, milestone goals from 2010 to 2030 are set out in accordance with the technology development environment and current status in China. This study identifies the critical technologies in capture, transport, utilization and storage of CO 2 and proposes technical priorities in the different stages of each technical aspect by evaluating indices such as the objective contribution rate and technical maturity, and gives recommendations on deployment of full-chain CCUS demonstration projects. Policies which would support CCUS are also suggested in this study. - Highlights: • A technology roadmap for CCUS development in China from 2010 to 2030 is presented. • Sound data and analysis in combination with expert workshops are used. • Critical technologies in CCUS are identified. • Priority actions of all stages are identified and proposed. • Guidance and recommendations for CCUS RD and D are provided

Energetic-environmental-economic assessment of the biogas system with three utilization pathways: Combined heat and power, biomethane and fuel cell.

Science.gov (United States)

Wu, Bin; Zhang, Xiangping; Shang, Dawei; Bao, Di; Zhang, Suojiang; Zheng, Tao

2016-08-01

A typical biogas system with three utilization pathways, i.e., biogas upgrading, biogas combined heat and power (CHP), biogas solid oxide fuel cells (SOFCs) were designed. It was assessed from the viewpoint of energy, environment and economy by using energy efficiency, green degree and net present value index respectively. The assessment considered the trade-off relationships among these indexes, which is more comprehensive than previous systematic evaluation work only included single or two of the pathway(s) by using one or two of the index(es). Assessment results indicated that biogas upgrading pathway has the highest systematic energy efficiency (46.5%) and shortest payback period (8.9year) with the green degree production is the lowest (9.29gd/day). While for biogas SOFC pathway, although the green degree production is the highest (21.77gd/day), the payback period is longer (14.5year) and the energy efficiency is 13.6% lower than the biogas upgrading pathway. Copyright © 2016 Elsevier Ltd. All rights reserved.

Developing pathways to low carbon land-based passenger transport in Great Britain by 2050

International Nuclear Information System (INIS)

Bristow, Abigail L.; Tight, Miles; Pridmore, Alison; May, Anthony D.

2008-01-01

The key aim of this paper is to examine strategic pathways to low carbon personal transport in Britain and to compare these with the current trajectory of transport policy. A 2050 baseline was established using trend information, forecasts and best evidence from the literature on response to policy intervention. A range of strategies are tested including: technological development, pricing, public transport and soft measures. We conclude that even dramatic technological advance cannot meet the more stringent targets for carbon reduction in the absence of considerable behavioural change. The most promising combinations of measures involve clear price signals to encourage both a reduction in the use of motorised transport and the development and purchase of more efficient vehicles; decarbonisation of public transport and facilitating measures to enhance access whilst reducing the need for motorised travel

Implementation of an acute venous thromboembolism clinical pathway reduces healthcare utilization and mitigates health disparities.

Science.gov (United States)

Misky, Gregory J; Carlson, Todd; Thompson, Elaina; Trujillo, Toby; Nordenholz, Kristen

2014-07-01

Acute venous thromboembolism (VTE) is prevalent, expensive, and deadly. Published data at our institution identified significant VTE care variation based on payer source. We developed a VTE clinical pathway to standardize care, decrease hospital utilization, provide education, and mitigate disparities. Target population for our interdisciplinary pathway was acute medical VTE patients. The intervention included order sets, system-wide education, follow-up phone calls, and coordinated posthospital care. Study data (n = 241) were compared to historical data (n = 234), evaluating outcomes of hospital admission, length of stay (LOS), and reutilization, stratified by payer source. A total of 241 patients entered the VTE clinical care pathway: 107 with deep venous thrombosis (44.4%) and 134 with a pulmonary embolism (55.6%). Within the pathway, uninsured VTE patients were admitted at a lower rate than insured patients (65.9 vs 79.1%; P = 0.032). LOS decreased from 4.4 to 3.1 days (P historical patients (9.4%, P = 0.254). Individual cost of care decreased from $7610 to $5295 (P cost, particularly among uninsured patients. Results of this novel study demonstrate a model for improving transitional care coordination with local community health clinics and delivering care to vulnerable populations. Other disease populations may benefit from the development of a similar model. © 2014 Society of Hospital Medicine.

Prediction method of unburnt carbon for coal fired utility boiler using image processing technique of combustion flame

International Nuclear Information System (INIS)

Shimoda, M.; Sugano, A.; Kimura, T.; Watanabe, Y.; Ishiyama, K.

1990-01-01

This paper reports on a method predicting unburnt carbon in a coal fired utility boiler developed using an image processing technique. The method consists of an image processing unit and a furnace model unit. temperature distribution of combustion flames can be obtained through the former unit. The later calculates dynamics of the carbon reduction from the burner stages to the furnace outlet using coal feed rate, air flow rate, chemical and ash content of coal. An experimental study shows that the prediction error of the unburnt carbon can be reduced to 10%

Bicarbonate-based cultivation of Dunaliella salina for enhancing carbon utilization efficiency.

Science.gov (United States)

Kim, Ga-Yeong; Heo, Jina; Kim, Hee-Sik; Han, Jong-In

2017-08-01

In this study, bicarbonate was proposed as an alternative carbon source to overcome exceedingly low CO 2 fixation efficiency of conventional microalgae cultivation system. 5gL -1 of sodium bicarbonate was found to well support the growth of Dunaliella salina, showing 2.84-fold higher specific growth rate than a bicarbonate-free control. This bicarbonate-fed cultivation also could yield biomass productivity similar to that of CO 2 -based system as long as pH was controlled. While the supplied CO 2 , because of its being a gas, was mostly lost and only 3.59% of it was used for biomass synthesis, bicarbonate was effectively incorporated into the biomass with 91.40% of carbon utilization efficiency. This study showed that the bicarbonate-based microalgae cultivation is indeed possible, and can even become a truly environment-friendly and workable approach, provided that a CO 2 mineralization technology is concomitantly established. Copyright © 2017 Elsevier Ltd. All rights reserved.

Insight into climate change from the carbon exchange of biocrusts utilizing non-rainfall water.

Science.gov (United States)

Ouyang, Hailong; Hu, Chunxiang

2017-05-31

Biocrusts are model ecosystems of global change studies. However, light and non-rainfall water (NRW) were previously few considered. Different biocrust types further aggravated the inconsistence. So carbon-exchange of biocrusts (cyanobacteria crusts-AC1/AC2; cyanolichen crust-LC1; chlorolichen crust-LC2; moss crust-MC) utilizing NRW at various temperatures and light-intensities were determined under simulated and insitu mesocosm experiments. Carbon input of all biocrusts were negatively correlated with experimental temperature under all light-intensity with saturated water and stronger light with equivalent NRW, but positively correlated with temperature under weak light with equivalent NRW. LCPs and R/Pg of AC1 were lowest, followed in turn by AC2, LC2 and MC. Thus AC1 had most opportunities to use NRW, and 2.5 °C warming did cause significant changes of carbon exchange. Structural equation models further revealed that air-temperature was most important for carbon-exchange of ACs, but equally important as NRW for LC2 and MC; positive influence of warming on carbon-input in ACs was much stronger than the latter. Therefore, temperature effect on biocrust carbon-input depends on both moisture and light. Meanwhile, the role of NRW, transitional states between ACs, and obvious carbon-fixation differences between lichen crusts should be fully considered in the future study of biocrusts responding to climate change.

Comparative genomic analysis of carbon and nitrogen assimilation mechanisms in three indigenous bioleaching bacteria: predictions and validations

Science.gov (United States)

Levicán, Gloria; Ugalde, Juan A; Ehrenfeld, Nicole; Maass, Alejandro; Parada, Pilar

2008-01-01

Background Carbon and nitrogen fixation are essential pathways for autotrophic bacteria living in extreme environments. These bacteria can use carbon dioxide directly from the air as their sole carbon source and can use different sources of nitrogen such as ammonia, nitrate, nitrite, or even nitrogen from the air. To have a better understanding of how these processes occur and to determine how we can make them more efficient, a comparative genomic analysis of three bioleaching bacteria isolated from mine sites in Chile was performed. This study demonstrated that there are important differences in the carbon dioxide and nitrogen fixation mechanisms among bioleaching bacteria that coexist in mining environments. Results In this study, we probed that both Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans incorporate CO2 via the Calvin-Benson-Bassham cycle; however, the former bacterium has two copies of the Rubisco type I gene whereas the latter has only one copy. In contrast, we demonstrated that Leptospirillum ferriphilum utilizes the reductive tricarboxylic acid cycle for carbon fixation. Although all the species analyzed in our study can incorporate ammonia by an ammonia transporter, we demonstrated that Acidithiobacillus thiooxidans could also assimilate nitrate and nitrite but only Acidithiobacillus ferrooxidans could fix nitrogen directly from the air. Conclusion The current study utilized genomic and molecular evidence to verify carbon and nitrogen fixation mechanisms for three bioleaching bacteria and provided an analysis of the potential regulatory pathways and functional networks that control carbon and nitrogen fixation in these microorganisms. PMID:19055775

High utilization platinum deposition on single-walled carbon nanotubes as catalysts for direct methanol fuel cell

International Nuclear Information System (INIS)

Wang, J.J.; Yin, G.P.; Zhang, J.; Wang, Z.B.; Gao, Y.Z.

2007-01-01

This research aims to enhance the activity of Pt catalysts, thus to lower the loading of Pt metal in fuel cell. Highly dispersed platinum supported on single-walled carbon nanotubes (SWNTs) as catalyst was prepared by ion exchange method. The homemade Pt/SWNTs underwent a repetition of ion exchange and reduction process in order to achieve an increase of the metal loading. For comparison, the similar loading of Pt catalyst supported on carbon nanotubes was prepared by borohydride reduction method. The catalysts were characterized by using energy dispersive analysis of X-ray (EDAX), transmission electron micrograph (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectrum (XPS). Compared with the Pt/SWNTs catalyst prepared by borohydride method, higher Pt utilization was achieved on the SWNTs by ion exchange method. Furthermore, in comparison to the E-TEK 20 wt.% Pt/C catalyst with the support of carbon black, the results from electrochemical measurement indicated that the Pt/SWNTs prepared by ion exchange method displayed a higher catalytic activity for methanol oxidation and higher Pt utilization, while no significant increasing in the catalytic activity of the Pt/SWNTs catalyst obtained by borohydride method

Complex carbon cycling processes and pathways in a tropical coastal marine environment (Saco do Mamangua, RJ - Brazil)

Science.gov (United States)

Giorgioni, M.; Jovane, L.; Millo, C.; Sawakuchi, H. O.; Bertassoli, D. J., Jr.; Gamba Romano, R.; Pellizari, V.; Castillo Franco, D.; Krusche, A. V.

2016-12-01

The Saco do Mamangua is a narrow and elongated gulf located along the southeastern coast of Brazil, in the state of Rio de Janeiro (RJ). It is surrounded by high relieves, which form a peculiar environment called riá, with little river input and limited water exchange with the Atlantic Ocean. These features make the Saco do Mamangua an ideal environment to study sedimentary carbon cycling under well-constrained boundary conditions in order to investigate if tropical coastal environments serve dominantly as potential carbon sinks or sources. In this work we integrate geochemical data from marine sediments and pore waters in the Saco do Mamangua with mapping of benthic microbial communities, in order to unravel the biogeochemical carbon cycling linked to the production of biogenic methane. Our results reveal that carbon cycling occurs in two parallel pathways. The Saco do Mamangua receives organic carbon both by surface runoff and by primary production in the water column. A large part of this organic carbon is buried within the sediment resulting in the production of biogenic methane, which gives rise to methane seepages at the sea floor. These methane seeps sustain methanotrophic microbial communities in the sediment pore water, but also escapes into the atmosphere by ebullition. Consequently, the sediments of Saco do Mamangua acts simultaneously as carbon sink and carbon source. Future work will allow us to accurately quantify the actual carbon fluxes and calculate the net carbon balance in the local environment.

Proteogenomic Characterization of Monocyclic Aromatic Hydrocarbon Degradation Pathways in the Aniline-Degrading Bacterium Burkholderia sp. K24.

Directory of Open Access Journals (Sweden)

Sang-Yeop Lee

Full Text Available Burkholderia sp. K24, formerly known as Acinetobacter lwoffii K24, is a soil bacterium capable of utilizing aniline as its sole carbon and nitrogen source. Genomic sequence analysis revealed that this bacterium possesses putative gene clusters for biodegradation of various monocyclic aromatic hydrocarbons (MAHs, including benzene, toluene, and xylene (BTX, as well as aniline. We verified the proposed MAH biodegradation pathways by dioxygenase activity assays, RT-PCR, and LC/MS-based quantitative proteomic analyses. This proteogenomic approach revealed four independent degradation pathways, all converging into the citric acid cycle. Aniline and p-hydroxybenzoate degradation pathways converged into the β-ketoadipate pathway. Benzoate and toluene were degraded through the benzoyl-CoA degradation pathway. The xylene isomers, i.e., o-, m-, and p-xylene, were degraded via the extradiol cleavage pathways. Salicylate was degraded through the gentisate degradation pathway. Our results show that Burkholderia sp. K24 possesses versatile biodegradation pathways, which may be employed for efficient bioremediation of aniline and BTX.

Proteogenomic Characterization of Monocyclic Aromatic Hydrocarbon Degradation Pathways in the Aniline-Degrading Bacterium Burkholderia sp. K24

Science.gov (United States)

Yun, Sung Ho; Choi, Chi-Won; Yi, Yoon-Sun; Kim, Jonghyun; Chung, Young-Ho; Park, Edmond Changkyun; Kim, Seung Il

2016-01-01

Burkholderia sp. K24, formerly known as Acinetobacter lwoffii K24, is a soil bacterium capable of utilizing aniline as its sole carbon and nitrogen source. Genomic sequence analysis revealed that this bacterium possesses putative gene clusters for biodegradation of various monocyclic aromatic hydrocarbons (MAHs), including benzene, toluene, and xylene (BTX), as well as aniline. We verified the proposed MAH biodegradation pathways by dioxygenase activity assays, RT-PCR, and LC/MS-based quantitative proteomic analyses. This proteogenomic approach revealed four independent degradation pathways, all converging into the citric acid cycle. Aniline and p-hydroxybenzoate degradation pathways converged into the β-ketoadipate pathway. Benzoate and toluene were degraded through the benzoyl-CoA degradation pathway. The xylene isomers, i.e., o-, m-, and p-xylene, were degraded via the extradiol cleavage pathways. Salicylate was degraded through the gentisate degradation pathway. Our results show that Burkholderia sp. K24 possesses versatile biodegradation pathways, which may be employed for efficient bioremediation of aniline and BTX. PMID:27124467

Proteomic analysis of carbon concentrating chemolithotrophic bacteria Serratia sp. for sequestration of carbon dioxide.

Science.gov (United States)

Bharti, Randhir K; Srivastava, Shaili; Thakur, Indu Shekhar

2014-01-01

A chemolithotrophic bacterium enriched in the chemostat in presence of sodium bicarbonate as sole carbon source was identified as Serratia sp. by 16S rRNA sequencing. Carbon dioxide sequestering capacity of bacterium was detected by carbonic anhydrase enzyme and ribulose-1, 5- bisphosphate carboxylase/oxygenase (RuBisCO). The purified carbonic anhydrase showed molecular weight of 29 kDa. Molecular weight of RuBisCO was 550 kDa as determined by fast protein liquid chromatography (FPLC), however, sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) showed presence of two subunits whose molecular weights were 56 and 14 kDa. The Western blot analysis of the crude protein and purified sample cross reacted with RuBisCO large-subunit polypeptides antibodies showed strong band pattern at molecular weight around 56 kDa regions. Whole cell soluble proteins of Serratia sp. grown under autotrophic and heterotrophic conditions were resolved by two-dimensional gel electrophoresis and MALDI-TOF/MS for differential expression of proteins. In proteomic analysis of 63 protein spots, 48 spots were significantly up-regulated in the autotrophically grown cells; seven enzymes showed its utilization in autotrophic carbon fixation pathways and other metabolic activities of bacterium including lipid metabolisms indicated sequestration potency of carbon dioxide and production of biomaterials.

Proteomic analysis of carbon concentrating chemolithotrophic bacteria Serratia sp. for sequestration of carbon dioxide.

Directory of Open Access Journals (Sweden)

Randhir K Bharti

Full Text Available A chemolithotrophic bacterium enriched in the chemostat in presence of sodium bicarbonate as sole carbon source was identified as Serratia sp. by 16S rRNA sequencing. Carbon dioxide sequestering capacity of bacterium was detected by carbonic anhydrase enzyme and ribulose-1, 5- bisphosphate carboxylase/oxygenase (RuBisCO. The purified carbonic anhydrase showed molecular weight of 29 kDa. Molecular weight of RuBisCO was 550 kDa as determined by fast protein liquid chromatography (FPLC, however, sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE showed presence of two subunits whose molecular weights were 56 and 14 kDa. The Western blot analysis of the crude protein and purified sample cross reacted with RuBisCO large-subunit polypeptides antibodies showed strong band pattern at molecular weight around 56 kDa regions. Whole cell soluble proteins of Serratia sp. grown under autotrophic and heterotrophic conditions were resolved by two-dimensional gel electrophoresis and MALDI-TOF/MS for differential expression of proteins. In proteomic analysis of 63 protein spots, 48 spots were significantly up-regulated in the autotrophically grown cells; seven enzymes showed its utilization in autotrophic carbon fixation pathways and other metabolic activities of bacterium including lipid metabolisms indicated sequestration potency of carbon dioxide and production of biomaterials.

Robust Control of PEP Formation Rate in the Carbon Fixation Pathway of C4 Plants by a Bi-functional Enzyme

Directory of Open Access Journals (Sweden)

Hart Yuval

2011-10-01

Full Text Available Abstract Background C4 plants such as corn and sugarcane assimilate atmospheric CO2 into biomass by means of the C4 carbon fixation pathway. We asked how PEP formation rate, a key step in the carbon fixation pathway, might work at a precise rate, regulated by light, despite fluctuations in substrate and enzyme levels constituting and regulating this process. Results We present a putative mechanism for robustness in C4 carbon fixation, involving a key enzyme in the pathway, pyruvate orthophosphate dikinase (PPDK, which is regulated by a bifunctional enzyme, Regulatory Protein (RP. The robust mechanism is based on avidity of the bifunctional enzyme RP to its multimeric substrate PPDK, and on a product-inhibition feedback loop that couples the system output to the activity of the bifunctional regulator. The model provides an explanation for several unusual biochemical characteristics of the system and predicts that the system's output, phosphoenolpyruvate (PEP formation rate, is insensitive to fluctuations in enzyme levels (PPDK and RP, substrate levels (ATP and pyruvate and the catalytic rate of PPDK, while remaining sensitive to the system's input (light levels. Conclusions The presented PPDK mechanism is a new way to achieve robustness using product inhibition as a feedback loop on a bifunctional regulatory enzyme. This mechanism exhibits robustness to protein and metabolite levels as well as to catalytic rate changes. At the same time, the output of the system remains tuned to input levels.

Dehydrogenation of Ethylbenzene with Carbon Dioxide as Soft Oxidant over Supported Vanadium-Antimony Oxide Catalyst

Energy Technology Data Exchange (ETDEWEB)

Hong, Do Young; Vislovskiy, Vladislav P.; Yoo, Jin S.; Chang, Jong San [Korea Research Institute of Chemical Technology, Daejeon (Korea, Republic of); Park, Sang Eon [Inha University, Incheon (Korea, Republic of); Park, Min Seok [Mongolia International University, Ulaanbaatar (Mongolia)

2005-11-15

This work presents that carbon dioxide, which is a main contributor to the global warming effect, could be utilized as a selective oxidant in the oxidative dehydrogenation of ethylbenzene. The dehydrogenation of ethylbenzene over alumina-supported vanadium-antimony oxide catalyst has been studied under different atmospheres such as inert nitrogen, steam, oxygen or carbon dioxide as diluent or oxidant. Among them, the addition of carbon dioxide gave the highest styrene yield (up to 82%) and styrene selectivity (up to 97%) along with stable activity. Carbon dioxide could play a beneficial role of a selective oxidant in the improvement of the catalytic behavior through the oxidative pathway.

Methane Carbon Isotopic Composition Reveals Changing Production Pathways Across a Gradient of Permafrost Thaw

Science.gov (United States)

Rocci, K.; Burke, S. A.; Clariza, P.; Malhotra, A.; McCalley, C. K.; Verbeke, B. A.; Werner, S. L.; Roulet, N. T.; Varner, R. K.

2017-12-01

Methane (CH4) emission in areas of discontinuous permafrost may increase with warming temperatures resulting in a positive feedback to climate change. Characterizing the production pathways of CH4, which may be inferred by measuring carbon isotopes, can help determine underlying mechanistic changes. We studied CH4 flux and isotopic composition of porewater (δ13C-CH4) in a sub-arctic peatland in Abisko, Sweden to understand controls on these factors across a thaw gradient during four growing seasons. Methane chamber flux measurements and porewater samples were collected in July 2013, and over the growing seasons of 2014 to 2016. Samples were analyzed on a Gas Chromatograph with a Flame Ionization Detector for CH4 concentrations and a Quantum Cascade Laser for carbon isotopes. Increased emission rates and changing isotopic signatures were observed across the thaw gradient throughout the growing season. While CH4 flux increased with increases in temperature and shallower water table, δ13C-CH4 exhibited a seasonal pattern that did not correlate with measured environmental variables, suggesting dependence on other factors. The most significant controlling factor for both flux and isotopic signature was plant community composition, specifically, the presence of graminoid species. Graminoid cover increases with thaw stage so both CH4 emissions and δ13C-CH4 are likely to increase in a warmer world, suggesting a shift toward the acetoclastic pathway of methane production.

Utilization of Activated Carbon Prepared from Aceh Coffee Grounds as Bio-sorbent for Treatment of Fertilizer Industrial Waste Water

Science.gov (United States)

Mariana, M.; Mahidin, M.; Mulana, F.; Aman, F.

2018-05-01

The people of Aceh are well known as coffee drinkers. Therefore, a lot of coffee shops have been established in Aceh in the past decade. The growing of coffee shops resulting to large amounts of coffee waste produced in Aceh Province that will become solid waste if not wisely utilized. The high carbon content in coffee underlined as background of this research to be utilized those used coffee grounds as bio-sorbent. The preparation of activated carbon from coffee grounds by using carbonization method that was initially activated with HCl was expected to increase the absorption capacity. The prepared activated carbon with high reactivity was applied to adsorb nitrite, nitrate and ammonia in wastewater outlet of PT. PIM wastewater pond. Morphological structure of coffee waste was analyzed by using Scanning Electron Microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The result showed that the adsorption capacity of iodine was equal to 856.578 mg/g. From the characterization results, it was concluded that the activated carbon from coffee waste complied to the permitted quality standards in accordance with the quality requirements of activated carbon SNI No. 06-3730-1995. Observed from the adsorption efficiency, the bio-sorbent showed a tendency of adsorbing more ammonia than nitrite and nitrate of PT. PIM wastewater with ammonia absorption efficiency of 56%.

The Glycerate and Phosphorylated Pathways of Serine Synthesis in Plants: The Branches of Plant Glycolysis Linking Carbon and Nitrogen Metabolism.

Science.gov (United States)

Igamberdiev, Abir U; Kleczkowski, Leszek A

2018-01-01

Serine metabolism in plants has been studied mostly in relation to photorespiration where serine is formed from two molecules of glycine. However, two other pathways of serine formation operate in plants and represent the branches of glycolysis diverging at the level of 3-phosphoglyceric acid. One branch (the glycerate - serine pathway) is initiated in the cytosol and involves glycerate formation from 3-phosphoglycerate, while the other (the phosphorylated serine pathway) operates in plastids and forms phosphohydroxypyruvate as an intermediate. Serine formed in these pathways becomes a precursor of glycine, formate and glycolate accumulating in stress conditions. The pathways can be linked to GABA shunt via transamination reactions and via participation of the same reductase for both glyoxylate and succinic semialdehyde. In this review paper we present a hypothesis of the regulation of redox balance in stressed plant cells via participation of the reactions associated with glycerate and phosphorylated serine pathways. We consider these pathways as important processes linking carbon and nitrogen metabolism and maintaining cellular redox and energy levels in stress conditions.

Resourceful utilization technology for natural gas

International Nuclear Information System (INIS)

Matsumura, Y.

1994-01-01

This paper is a description of new applications that will contribute in increasing the demand for natural gas. First, technical issues to turn natural gas into a more resourceful fuel (efficient transportation and storage, integrated utilization of energies, uses as non-fuel), and also pitch-based high performance carbon materials and utilization techniques in the field of energy (isotropic carbon fiber, activated carbon fiber, spherical carbon micro-beads, high modulus carbon fiber). (TEC)

Comparative genomic analysis of carbon and nitrogen assimilation mechanisms in three indigenous bioleaching bacteria: predictions and validations

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Ehrenfeld Nicole

2008-12-01

Full Text Available Abstract Background Carbon and nitrogen fixation are essential pathways for autotrophic bacteria living in extreme environments. These bacteria can use carbon dioxide directly from the air as their sole carbon source and can use different sources of nitrogen such as ammonia, nitrate, nitrite, or even nitrogen from the air. To have a better understanding of how these processes occur and to determine how we can make them more efficient, a comparative genomic analysis of three bioleaching bacteria isolated from mine sites in Chile was performed. This study demonstrated that there are important differences in the carbon dioxide and nitrogen fixation mechanisms among bioleaching bacteria that coexist in mining environments. Results In this study, we probed that both Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans incorporate CO2 via the Calvin-Benson-Bassham cycle; however, the former bacterium has two copies of the Rubisco type I gene whereas the latter has only one copy. In contrast, we demonstrated that Leptospirillum ferriphilum utilizes the reductive tricarboxylic acid cycle for carbon fixation. Although all the species analyzed in our study can incorporate ammonia by an ammonia transporter, we demonstrated that Acidithiobacillus thiooxidans could also assimilate nitrate and nitrite but only Acidithiobacillus ferrooxidans could fix nitrogen directly from the air. Conclusion The current study utilized genomic and molecular evidence to verify carbon and nitrogen fixation mechanisms for three bioleaching bacteria and provided an analysis of the potential regulatory pathways and functional networks that control carbon and nitrogen fixation in these microorganisms.

Kinetics of inorganic carbon utilization by microalgal biofilm in a flat plate photoreactor

Energy Technology Data Exchange (ETDEWEB)

Lin, Y.H.; Leu, J.Y.; Lan, C.R.; Lin, P.H.P.; Chang, F.L. [Development Center for Biotechnology, Taipei (Taiwan). Dept. for Environmental Program

2003-11-01

A kinetic model was developed to describe inorganic carbon utilization by microalgae biofilm in a flat plate photoreactor. The model incorporates the fundamental mechanisms of diffusive mass transport and biological reaction of inorganic carbon by microalgal biofilm. An advanced numerical technique, the orthogonal collocation method and Gear's method, was employed to solve this kinetic model. The model solutions included the concentration profiles of inorganic carbon in the microalgal biofilm, the growths of suspended microalgae and microalgal biofilm, the effluent concentrations of inorganic carbon, and the flux of inorganic carbon from bulk liquid into biofilm. The batch kinetic test was independently conducted to determine biokinetic parameters used in the microalgal biofilm model simulation while initial thickness of microalgal biofilm were assumed. A laboratory-scale flat plate photoreactor with a high recycle flow rate was set up and conducted to verify the model. The volume of photoreactor is 60 l which yields a hydraulic retention time of 1.67 days. The model-generated inorganic carbon and the suspended microalgae concentration curves agreed well with those obtained in the laboratory-scale test. The fixation efficiencies of HCO{sub 3}{sup -} and CO{sub 2} are 98.5% and 90% at a steady-state condition, respectively. The concentration of suspended microalgal cell reached up to 12 mg/l at a maximum growth rate while the thickness of microalgal biofilm was estimated to be 104 pm at a steady-state condition. The approaches of experiments and model simulation presented in this study could be employed for the design of a flat plate photoreactor to treat CO{sub 2} by microalgal biofilm in a fossil-fuel power plant.

Regulation of energy partitioning and alternative electron transport pathways during cold acclimation of lodgepole pine is oxygen dependent.

Science.gov (United States)

Savitch, Leonid V; Ivanov, Alexander G; Krol, Marianna; Sprott, David P; Oquist, Gunnar; Huner, Norman P A

2010-09-01

Second year needles of Lodgepole pine (Pinus contorta L.) were exposed for 6 weeks to either simulated control summer ['summer'; 25 °C/250 photon flux denisty (PFD)], autumn ('autumn'; 15°C/250 PFD) or winter conditions ('winter'; 5 °C/250 PFD). We report that the proportion of linear electron transport utilized in carbon assimilation (ETR(CO2)) was 40% lower in both 'autumn' and 'winter' pine when compared with the 'summer' pine. In contrast, the proportion of excess photosynthetic linear electron transport (ETR(excess)) not used for carbon assimilation within the total ETR(Jf) increased by 30% in both 'autumn' and 'winter' pine. In 'autumn' pine acclimated to 15°C, the increased amounts of 'excess' electrons were directed equally to 21  kPa O2-dependent and 2  kPa O2-dependent alternative electron transport pathways and the fractions of excitation light energy utilized by PSII photochemistry (Φ(PSII)), thermally dissipated through Φ(NPQ) and dissipated by additional quenching mechanism(s) (Φ(f,D)) were similar to those in 'summer' pine. In contrast, in 'winter' needles acclimated to 5 °C, 60% of photosynthetically generated 'excess' electrons were utilized through the 2  kPa O2-dependent electron sink and only 15% by the photorespiratory (21  kPa O2) electron pathway. Needles exposed to 'winter' conditions led to a 3-fold lower Φ(PSII), only a marginal increase in Φ(NPQ) and a 2-fold higher Φ(f,D), which was O2 dependent compared with the 'summer' and 'autumn' pine. Our results demonstrate that the employment of a variety of alternative pathways for utilization of photosynthetically generated electrons by Lodgepole pine depends on the acclimation temperature. Furthermore, dissipation of excess light energy through constitutive non-photochemical quenching mechanisms is O2 dependent.

Models of Plankton Community Changes during a Warm Water Anomaly in Arctic Waters Show Altered Trophic Pathways with Minimal Changes in Carbon Export

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Maria Vernet

2017-05-01

Full Text Available Carbon flow through pelagic food webs is an expression of the composition, biomass and activity of phytoplankton as primary producers. In the near future, severe environmental changes in the Arctic Ocean are expected to lead to modifications of phytoplankton communities. Here, we used a combination of linear inverse modeling and ecological network analysis to study changes in food webs before, during, and after an anomalous warm water event in the eastern Fram Strait of the West Spitsbergen Current (WSC that resulted in a shift from diatoms to flagellates during the summer (June–July. The model predicts substantial differences in the pathways of carbon flow in diatom- vs. Phaeocystis/nanoflagellate-dominated phytoplankton communities, but relatively small differences in carbon export. The model suggests a change in the zooplankton community and activity through increasing microzooplankton abundance and the switching of meso- and macrozooplankton feeding from strict herbivory to omnivory, detritivory and coprophagy. When small cells and flagellates dominated, the phytoplankton carbon pathway through the food web was longer and the microbial loop more active. Furthermore, one step was added in the flow from phytoplankton to mesozooplankton, and phytoplankton carbon to higher trophic levels is available via detritus or microzooplankton. Model results highlight how specific changes in phytoplankton community composition, as expected in a climate change scenario, do not necessarily lead to a reduction in carbon export.

Enhancing substrate utilization and power production of a microbial fuel cell with nitrogen-doped carbon aerogel as cathode catalyst.

Science.gov (United States)

Tardy, Gábor Márk; Lóránt, Bálint; Lóka, Máté; Nagy, Balázs; László, Krisztina

2017-07-01

Catalytic efficiency of a nitrogen-doped, mesoporous carbon aerogel cathode catalyst was investigated in a two-chambered microbial fuel cell (MFC) applying graphite felt as base material for cathode and anode, utilizing peptone as carbon source. This mesoporous carbon aerogel containing catalyst layer on the cathode increased the maximum power density normalized to the anode volume to 2.7 times higher compared to the maximum power density obtained applying graphite felt cathode without the catalyst layer. At high (2 and 3) cathode/anode volume ratios, maximum power density exceeded 40 W m -3 . At the same time, current density and specific substrate utilization rate increased by 58% resulting in 31.9 A m -3 and 18.8 g COD m -3  h -1 , respectively (normalized to anode volume). Besides the increase of the power and the rate of biodegradation, the investigated catalyst decreased the internal resistance from the range of 450-600 to 350-370 Ω. Although Pt/C catalyst proved to be more efficient, a considerable decrease in the material costs might be achieved by substituting it with nitrogen-doped carbon aerogel in MFCs. Such cathode still displays enhanced catalytic effect.

Carbon deposition thresholds on nickel-based solid oxide fuel cell anodes I. Fuel utilization

Science.gov (United States)

Kuhn, J.; Kesler, O.

2015-03-01

In the first of a two part publication, the effect of fuel utilization (Uf) on carbon deposition rates in solid oxide fuel cell nickel-based anodes was studied. Representative 5-component CH4 reformate compositions (CH4, H2, CO, H2O, & CO2) were selected graphically by plotting the solutions to a system of mass-balance constraint equations. The centroid of the solution space was chosen to represent a typical anode gas mixture for each nominal Uf value. Selected 5-component and 3-component gas mixtures were then delivered to anode-supported cells for 10 h, followed by determination of the resulting deposited carbon mass. The empirical carbon deposition thresholds were affected by atomic carbon (C), hydrogen (H), and oxygen (O) fractions of the delivered gas mixtures and temperature. It was also found that CH4-rich gas mixtures caused irreversible damage, whereas atomically equivalent CO-rich compositions did not. The coking threshold predicted by thermodynamic equilibrium calculations employing graphite for the solid carbon phase agreed well with empirical thresholds at 700 °C (Uf ≈ 32%); however, at 600 °C, poor agreement was observed with the empirical threshold of ∼36%. Finally, cell operating temperatures correlated well with the difference in enthalpy between the supplied anode gas mixtures and their resulting thermodynamic equilibrium gas mixtures.

Carbon dioxide conversion over carbon-based nanocatalysts.

Science.gov (United States)

Khavarian, Mehrnoush; Chai, Siang-Piao; Mohamed, Abdul Rahman

2013-07-01

The utilization of carbon dioxide for the production of valuable chemicals via catalysts is one of the efficient ways to mitigate the greenhouse gases in the atmosphere. It is known that the carbon dioxide conversion and product yields are still low even if the reaction is operated at high pressure and temperature. The carbon dioxide utilization and conversion provides many challenges in exploring new concepts and opportunities for development of unique catalysts for the purpose of activating the carbon dioxide molecules. In this paper, the role of carbon-based nanocatalysts in the hydrogenation of carbon dioxide and direct synthesis of dimethyl carbonate from carbon dioxide and methanol are reviewed. The current catalytic results obtained with different carbon-based nanocatalysts systems are presented and how these materials contribute to the carbon dioxide conversion is explained. In addition, different strategies and preparation methods of nanometallic catalysts on various carbon supports are described to optimize the dispersion of metal nanoparticles and catalytic activity.

Pathways for Off-site Corporate PV Procurement

Energy Technology Data Exchange (ETDEWEB)

Heeter, Jenny S [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-09-06

Through July 2017, corporate customers contracted for more than 2,300 MW of utility-scale solar. This paper examines the benefits, challenges, and outlooks for large-scale off-site solar purchasing through four pathways: power purchase agreements, retail choice, utility partnerships (green tariffs and bilateral contracts with utilities), and by becoming a licensed wholesale seller of electricity. Each pathway differs based on where in the United States it is available, the value provided to a corporate off-taker, and the ease of implementation. The paper concludes with a discussion of future pathway comparison, noting that to deploy more corporate off-site solar, new procurement pathways are needed.

Amending the Structure of Renewable Carbon from Biorefinery Waste-Streams for Energy Storage Applications.

Science.gov (United States)

Ho, Hoi Chun; Goswami, Monojoy; Chen, Jihua; Keum, Jong K; Naskar, Amit K

2018-05-29

Biorefineries produce impure sugar waste streams that are being underutilized. By converting this waste to a profitable by-product, biorefineries could be safeguarded against low oil prices. We demonstrate controlled production of useful carbon materials from the waste concentrate via hydrothermal synthesis and carbonization. We devise a pathway to producing tunable, porous spherical carbon materials by modeling the gross structure formation and developing an understanding of the pore formation mechanism utilizing simple reaction principles. Compared to a simple hydrothermal synthesis from sugar concentrate, emulsion-based synthesis results in hollow spheres with abundant microporosity. In contrast, conventional hydrothermal synthesis produces solid beads with micro and mesoporosity. All the carbonaceous materials show promise in energy storage application. Using our reaction pathway, perfect hollow activated carbon spheres can be produced from waste sugar in liquid effluence of biomass steam pretreatment units. The renewable carbon product demonstrated a desirable surface area of 872 m 2 /g and capacitance of up to 109 F/g when made into an electric double layer supercapacitor. The capacitor exhibited nearly ideal capacitive behavior with 90.5% capacitance retention after 5000 cycles.

A thermodynamic solution model for calcium carbonate: Towards an understanding of multi-equilibria precipitation pathways.

Science.gov (United States)

Donnet, Marcel; Bowen, Paul; Lemaître, Jacques

2009-12-15

Thermodynamic solubility calculations are normally only related to thermodynamic equilibria in solution. In this paper, we extend the use of such solubility calculations to help elucidate possible precipitation reaction pathways during the entire reaction. We also estimate the interfacial energy of particles using only solubility data by a modification of Mersmann's approach. We have carried this out by considering precipitation reactions as a succession of small quasi-equilibrium states. Thus possible equilibrium precipitation pathways can be evaluated by calculating the evolution of surface charge, particle size and/or interfacial energy during the ongoing reaction. The approach includes the use of the Kelvin's law to express the influence of particle size on the solubility constant of precipitates, the use of Nernst's law to calculate surface potentials from solubility calculations and relate this to experimentally measured zeta potentials. Calcium carbonate precipitation and zeta potential measurements of well characterised high purity calcite have been used as a model system to validate the calculated values. The clarification of the change in zeta potential on titration illustrates the power of this approach as a tool for reaction pathway prediction and hence knowledge based tailoring of precipitation reactions.

Molecular mechanisms behind the adjustment of phototrophic light-harvesting and mixotrophic utilization of cellulosic carbon sources in Chlamydomonas reinhardtii

OpenAIRE

Blifernez-Klassen, Olga

2012-01-01

Plants, green algae and cyanobacteria perform photosynthetic conversion of sunlight into chemical energy in a permanently changing natural environment, where the efficient utilization of light and inorganic carbon represent the most critical factors. Photosynthetic organisms have developed different acclimation strategies to adapt changing light conditions and insufficient carbon source supply in order to survive and to assure optimal growth and protection. This thesis provides further insigh...

The 380 kb pCMU01 plasmid encodes chloromethane utilization genes and redundant genes for vitamin B12- and tetrahydrofolate-dependent chloromethane metabolism in Methylobacterium extorquens CM4: a proteomic and bioinformatics study.

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Sandro Roselli

Full Text Available Chloromethane (CH3Cl is the most abundant volatile halocarbon in the atmosphere and contributes to the destruction of stratospheric ozone. The only known pathway for bacterial chloromethane utilization (cmu was characterized in Methylobacterium extorquens CM4, a methylotrophic bacterium able to utilize compounds without carbon-carbon bonds such as methanol and chloromethane as the sole carbon source for growth. Previous work demonstrated that tetrahydrofolate and vitamin B12 are essential cofactors of cmuA- and cmuB-encoded methyltransferases of chloromethane dehalogenase, and that the pathway for chloromethane utilization is distinct from that for methanol. This work reports genomic and proteomic data demonstrating that cognate cmu genes are located on the 380 kb pCMU01 plasmid, which drives the previously defined pathway for tetrahydrofolate-mediated chloromethane dehalogenation. Comparison of complete genome sequences of strain CM4 and that of four other M. extorquens strains unable to grow with chloromethane showed that plasmid pCMU01 harbors unique genes without homologs in the compared genomes (bluB2, btuB, cobA, cbiD, as well as 13 duplicated genes with homologs of chromosome-borne genes involved in vitamin B12-associated biosynthesis and transport, or in tetrahydrofolate-dependent metabolism (folC2. In addition, the presence of both chromosomal and plasmid-borne genes for corrinoid salvaging pathways may ensure corrinoid coenzyme supply in challenging environments. Proteomes of M. extorquens CM4 grown with one-carbon substrates chloromethane and methanol were compared. Of the 49 proteins with differential abundance identified, only five (CmuA, CmuB, PurU, CobH2 and a PaaE-like uncharacterized putative oxidoreductase are encoded by the pCMU01 plasmid. The mainly chromosome-encoded response to chloromethane involves gene clusters associated with oxidative stress, production of reducing equivalents (PntAA, Nuo complex, conversion of

Using program impact pathways to understand and improve program delivery, utilization, and potential for impact of Helen Keller International's homestead food production program in Cambodia.

Science.gov (United States)

Olney, Deanna K; Vicheka, Sao; Kro, Meng; Chakriya, Chhom; Kroeun, Hou; Hoing, Ly Sok; Talukder, Aminzzaman; Quinn, Victoria; Iannotti, Lora; Becker, Elisabeth; Roopnaraine, Terry

2013-06-01

Evidence of the impact of homestead food production programs on nutrition outcomes such as anemia and growth is scant. In the absence of information on program impact pathways, it is difficult to understand why these programs, which have been successful in increasing intake of micronutrient-rich foods, have had such limited documented impact on nutrition outcomes. To conduct a process evaluation of Helen Keller International's (HKI's) homestead food production program in Cambodia to assess whether the program was operating as planned (in terms of design, delivery, and utilization) and to identify ways in which the program might need to be strengthened in order to increase its potential for impact. A program theory framework, which laid out the primary components along the hypothesized program impact pathways, was developed in collaboration with HKI and used to design the research. Semistructured interviews and focus group discussions with program beneficiaries (n = 36 and 12, respectively), nonbeneficiaries (n = 12), and program implementers (n = 17 and 2, respectively) and observations of key program delivery points, including health and nutrition training sessions (n = 6), village model farms (n = 6), and household gardens of beneficiaries (n = 36) and nonbeneficiaries (n = 12), were conducted to assess the delivery and utilization of the primary program components along the impact pathways. The majority of program components were being delivered and utilized as planned. However, challenges with some of the key components posited to improve outcomes such as anemia and growth were noted. Among these were a gap in the expected pathway from poultry production to increased intake of eggs and poultry meat, and some weaknesses in the delivery of the health and nutrition training sessions and related improvements in knowledge among the village health volunteers and beneficiaries. Although the program has been successful in delivering the majority of the program

Disruption of the folate pathway in zebrafish causes developmental defects

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Lee Marina S

2012-04-01

Full Text Available Abstract Background Folic acid supplementation reduces the risk of neural tube defects and congenital heart defects. The biological mechanisms through which folate prevents birth defects are not well understood. We explore the use of zebrafish as a model system to investigate the role of folate metabolism during development. Results We first identified zebrafish orthologs of 12 human folate metabolic genes. RT-PCR and in situ analysis indicated maternal transcripts supply the embryo with mRNA so that the embryo has an intact folate pathway. To perturb folate metabolism we exposed zebrafish embryos to methotrexate (MTX, a potent inhibitor of dihydrofolate reductase (Dhfr an essential enzyme in the folate metabolic pathway. Embryos exposed to high doses of MTX exhibited developmental arrest prior to early segmentation. Lower doses of MTX resulted in embryos with a shortened anterior-posterior axis and cardiac defects: linear heart tubes or incomplete cardiac looping. Inhibition of dhfr mRNA with antisense morpholino oligonucleotides resulted in embryonic lethality. One function of the folate pathway is to provide essential one-carbon units for dTMP synthesis, a rate-limiting step of DNA synthesis. After 24 hours of exposure to high levels of MTX, mutant embryos continue to incorporate the thymidine analog BrdU. However, additional experiments indicate that these embryos have fewer mitotic cells, as assayed with phospho-histone H3 antibodies, and that treated embryos have perturbed cell cycles. Conclusions Our studies demonstrate that human and zebrafish utilize similar one-carbon pathways. Our data indicate that folate metabolism is essential for early zebrafish development. Zebrafish studies of the folate pathway and its deficiencies could provide insight into the underlying etiology of human birth defects and the natural role of folate in development.

[Impact of Land Utilization Pattern on Distributing Characters of Labile Organic Carbon in Soil Aggregates in Jinyun Mountain].

Science.gov (United States)

Li, Rui; Jiang, Chang-sheng; Hao, Qing-ju

2015-09-01

Four land utilization patterns were selected for this study in Jinyun mountain, including subtropical evergreen broad-leaved forest (abbreviation: forest), sloping farmland, orchard and abandoned land. Soil samples were taken every 10 cm in the depth of 60 cm soil and proportions of large macroaggregates (> 2 mm), small macroaggregates (0. 25-2 mm), microaggregates (0. 053 - 0. 25 mm) and silt + clay (organic carbon and labile organic carbon in each aggregate fraction and analyze impacts of land uses on organic carbon and labile organic carbon of soil aggregates. LOC content of four soil aggregates were significantly reduced with the increase of soil depth; in layers of 0-60 cm soil depth, our results showed that LOC contents of forest and abandoned land were higher than orchard and sloping farmland. Reserves of labile organic carbon were estimated by the same soil quality, it revealed that forest (3. 68 Mg.hm-2) > abandoned land (1. 73 Mg.hm-2) > orchard (1. 43 Mg.hm-2) >sloping farmland (0.54 Mg.hm-2) in large macroaggregates, abandoned land (7.77, 5. 01 Mg.hm-2) > forest (4. 96, 2.71 Mg.hm-2) > orchard (3. 33, 21. 10 Mg.hm-2) > sloping farmland (1. 68, 1. 35 Mg.hm-2) in small macroaggregates and microaggregates, and abandoned land(4. 32 Mg.hm-2) > orchard(4. 00 Mg.hm-2) > forest(3. 22 Mg.hm-2) > sloping farmland (2.37 Mg.hm-2) in silt + clay, forest and abandoned land were higher than orchard and sloping farmland in other three soil aggregates except silt + clay. It was observed that the level of organic carbon and labile organic carbon were decreased when bringing forest under cultivation to orchard or farmland, and augments on organic carbon and labile organic carbon were found after exchanging farmland to abandoned land. The most reverses of forest and abandoned land emerged in small macroaggregates, orchard and sloping farmland were in microaggregates. That was, during the transformations of land utilization pattern, soil aggregates with bigger size were

Isolation and characterization of a bacterium which utilizes polyester polyurethane as a sole carbon and nitrogen source.

Science.gov (United States)

Nakajima-Kambe, T; Onuma, F; Kimpara, N; Nakahara, T

1995-06-01

Various soil samples were screened for the presence of microorganisms which have the ability to degrade polyurethane compounds. Two strains with good polyurethane degrading activity were isolated. The more active strain was tentatively identified as Comamonas acidovorans. This strain could utilize polyester-type polyurethanes but not the polyether-type polyurethanes as sole carbon and nitrogen sources. Adipic acid and diethylene glycol were probably the main degradation products when polyurethane was supplied as a sole carbon and nitrogen source. When ammonium nitrate was used as nitrogen source, only diethylene glycol was detected after growth on polyurethane.

An Integrative Approach to Energy, Carbon, and Redox Metabolism in the Cyanobacterium Synechocystis sp. PCC 6803. Special Report

Energy Technology Data Exchange (ETDEWEB)

Overbeek, R.

2003-06-30

The main objectives for the first year were to produce a detailed metabolic reconstruction of synechocystis sp. PCC 6803 especially in interrelated areas of photosynthesis, respiration, and central carbon metabolism to support a more complete understanding and modeling of this organism. Additionally, Integrated Genomics, Inc., provided detailed bioinformatic analysis of selected functional systems related to carbon and energy generation and utilization, and of the corresponding pathways, functional roles and individual genes to support wet lab experiments by collaborators.

Economics of carbon dioxide capture and utilization-a supply and demand perspective.

Science.gov (United States)

Naims, Henriette

2016-11-01

Lately, the technical research on carbon dioxide capture and utilization (CCU) has achieved important breakthroughs. While single CO 2 -based innovations are entering the markets, the possible economic effects of a large-scale CO 2 utilization still remain unclear to policy makers and the public. Hence, this paper reviews the literature on CCU and provides insights on the motivations and potential of making use of recovered CO 2 emissions as a commodity in the industrial production of materials and fuels. By analyzing data on current global CO 2 supply from industrial sources, best practice benchmark capture costs and the demand potential of CO 2 utilization and storage scenarios with comparative statics, conclusions can be drawn on the role of different CO 2 sources. For near-term scenarios the demand for the commodity CO 2 can be covered from industrial processes, that emit CO 2 at a high purity and low benchmark capture cost of approximately 33 €/t. In the long-term, with synthetic fuel production and large-scale CO 2 utilization, CO 2 is likely to be available from a variety of processes at benchmark costs of approx. 65 €/t. Even if fossil-fired power generation is phased out, the CO 2 emissions of current industrial processes would suffice for ambitious CCU demand scenarios. At current economic conditions, the business case for CO 2 utilization is technology specific and depends on whether efficiency gains or substitution of volatile priced raw materials can be achieved. Overall, it is argued that CCU should be advanced complementary to mitigation technologies and can unfold its potential in creating local circular economy solutions.

DES/CCHP: The best utilization mode of natural gas for China’s low carbon economy

International Nuclear Information System (INIS)

Li, Yajun; Xia, Yan

2013-01-01

In this paper, through the analysis of the great challenges faced by China’s energy industry in the development of low carbon economy, it is advisable that China increase the proportion of natural gas (NG) in primary energy as the main strategy of energy conservation and CO 2 reduction in the advancement of industrialization and urbanization. In the near future, NG will become one of the major energy suppliers for new towns and industrial parks, and work for electric peak shaving when used in distributed energy system/combined cold, heat and power (DES/CCHP). However, as an efficient approach to improve the energy utilization efficiency, DES/CCHP cannot only increase the current energy efficiency from 33% to 50.3% (the world’s average), but also reduce the cost of terminal supplies of power, cold, steam and hot water. It will become one of the most important means to control CO 2 emissions in the next 20 years, and is essential to China’s low carbon industrialization and urbanization. - Highlights: ► China’s high economic growth has lead to a huge amount of carbon emissions. ► Climate change calls for a low carbon economy in China. ► The pressure of carbon emission reduction requires China reduce the excessive dependency on coal and oil. ► Natural gas used in distributed energy system/combined cold, heat and power (NG DES/CCHP) is low in carbon emission. ► NG DES/CCHP is the optimal energy supplier for a low carbon economy in China.

The role of mass transport pathway in wormholelike mesoporous carbon for supercapacitors.

Science.gov (United States)

Liang, Yeru; Liang, Fengxue; Li, Zhenghui; Wu, Dingcai; Yan, Fangyu; Li, Siyu; Fu, Ruowen

2010-09-28

In the present paper, we demonstrate the importance of the role of a mass transport pathway (MTP) in wormholelike mesoporous carbon (WMC) through studying the ion diffusion behaviors within two different wormholelike mesopore networks with and without MTP. Our results reveal that the introduction of MTP is very helpful in improving ion diffusion properties. The as-prepared WMC with a MTP of ca. 9.7 nm exhibits notably better electric double layer performance as compared to the conventional WMC without a MTP. For example, even at the quick sweep rate of 50 mV s(-1), the surface specific capacitance of the former is 21.6 microF cm(-2), which is almost 4 times as high as that of the latter (5.5 microF cm(-2)).

CO2 Reduction Catalyzed by Nitrogenase: Pathways to Formate, Carbon Monoxide, and Methane

OpenAIRE

Khadka, Nimesh; Dean, Dennis R.; Smith, Dayle; Hoffman, Brian M.; Raugei, Simone; Seefeldt, Lance C.

2016-01-01

The reduction of N2 to NH3 by Mo-dependent nitrogenase at its active-site metal cluster FeMo-cofactor utilizes reductive elimination (re) of Fe-bound hydrides with obligatory loss of H2 to activate the enzyme for binding/reduction of N2. Earlier work showed that wild type nitrogenase and a nitrogenase having amino acid substitutions in the MoFe protein near FeMo-cofactor can catalytically reduce CO2 by 2 or 8 electrons/protons to carbon monoxide (CO) and methane (CH4) at low rates. Here, it i...

Photosynthetic carbon metabolism in seagrasses C-labeling evidence for the c(3) pathway.

Science.gov (United States)

Andrews, T J; Abel, K M

1979-04-01

The delta(13)C values of several seagrasses were considerably less negative than those of terrestrial C(3) plants and tended toward those of terrestrial C(4) plants. However, for Thalassia hemprichii (Ehrenb.) Aschers and Halophila spinulosa (R. Br.) Aschers, phosphoglycerate and other C(3) cycle intermediates predominated among the early labeled products of photosynthesis in (14)C-labeled seawater (more than 90% at the earliest times) and the labeling pattern at longer times was brought about by the operation of the C(3) pathway. Malate and aspartate together accounted for only a minor fraction of the total fixed label at all times and the kinetic data of this labeling were not at all consistent with these compounds being early intermediates in seagrass photosynthesis. Pulse-chase (14)C-labeling studies further substantiated these conclusions. Significant labeling of photorespiratory intermediates was observed in all experiments. The kinetics of total fixation of label during some steady-state and pulse-chase experiments suggested that there may be an intermediate pool of inorganic carbon of variable size closely associated with the leaves, either externally or internally. Such a pool may be one cause for the C(4)-like carbon isotope ratios of seagrasses.

Sequestration and utilization of carbon dioxide by chemical and biological methods for biofuels and biomaterials by chemoautotrophs: Opportunities and challenges.

Science.gov (United States)

Thakur, Indu Shekhar; Kumar, Manish; Varjani, Sunita J; Wu, Yonghong; Gnansounou, Edgard; Ravindran, Sindhu

2018-05-01

To meet the CO 2 emission reduction targets, carbon dioxide capture and utilization (CCU) comes as an evolve technology. CCU concept is turning into a feedstock and technologies have been developed for transformation of CO 2 into useful organic products. At industrial scale, utilization of CO 2 as raw material is not much significant as compare to its abundance. Mechanisms in nature have evolved for carbon concentration, fixation and utilization. Assimilation and subsequent conversion of CO 2 into complex molecules are performed by the photosynthetic and chemolithotrophic organisms. In the last three decades, substantial research is carry out to discover chemical and biological conversion of CO 2 in various synthetic and biological materials, such as carboxylic acids, esters, lactones, polymer biodiesel, bio-plastics, bio-alcohols, exopolysaccharides. This review presents an over view of catalytic transformation of CO 2 into biofuels and biomaterials by chemical and biological methods. Copyright © 2018 Elsevier Ltd. All rights reserved.

Utilization of carbon/carbon composites in nuclear simulation fuel rods

International Nuclear Information System (INIS)

Polidoro, H.A.; Otani, S.; Rezende, M.C.; Ferreira, S.R.; Otani, C.

1988-01-01

Thermo-hydraulic problems, in nuclear plants are normally analysed by using electrically heated rods. Carbon/carbon composites were used to make heating elements for testing by indirect heating up to a heat flux of 100 W/cm 2 . It is easy to verify that this value can be exceed if the choice of the complementary materials for insulator and cladding were improved. The swaging process used to reduce the cladding diameter prevented the fabrication of graphite heater rods. (author) [pt

Microbial mineralization of ring-substituted anilines through an ortho-cleavage pathway.

Science.gov (United States)

Zeyer, J; Wasserfallen, A; Timmis, K N

1985-08-01

Moraxella sp. strain G is able to utilize as sole source of carbon and nitrogen aniline, 4-fluoroaniline, 2-chloroaniline, 3-chloroaniline, 4-chloroaniline (PCA), and 4-bromoaniline but not 4-iodoaniline, 4-methylaniline, 4-methoxyaniline, or 3,4-dichloroaniline. The generation time on PCA was 6 h. The pathway for the degradation of PCA was investigated by analysis of catabolic intermediates and enzyme activities. Mutants of strain G were isolated to enhance the accumulation of specific pathway intermediates. PCA was converted by an aniline oxygenase to 4-chlorocatechol, which in turn was degraded via a modified ortho-cleavage pathway. Synthesis of the aniline oxygenase was inducible by various anilines. This enzyme exhibited a broad substrate specificity. Its specific activity towards substituted anilines seemed to be correlated more with the size than with the electron-withdrawing effect of the substituent and was very low towards anilines having substituents larger than iodine or a methyl group. The initial enzyme of the modified ortho-cleavage pathway, catechol 1,2-dioxygenase, had similar characteristics to those of corresponding enzymes of pathways for the degradation of chlorobenzoic acid and chlorophenol, that is, a broad substrate specificity and high activity towards chlorinated and methylated catechols.

Pathway Distiller - multisource biological pathway consolidation.

Science.gov (United States)

Doderer, Mark S; Anguiano, Zachry; Suresh, Uthra; Dashnamoorthy, Ravi; Bishop, Alexander J R; Chen, Yidong

2012-01-01

One method to understand and evaluate an experiment that produces a large set of genes, such as a gene expression microarray analysis, is to identify overrepresentation or enrichment for biological pathways. Because pathways are able to functionally describe the set of genes, much effort has been made to collect curated biological pathways into publicly accessible databases. When combining disparate databases, highly related or redundant pathways exist, making their consolidation into pathway concepts essential. This will facilitate unbiased, comprehensive yet streamlined analysis of experiments that result in large gene sets. After gene set enrichment finds representative pathways for large gene sets, pathways are consolidated into representative pathway concepts. Three complementary, but different methods of pathway consolidation are explored. Enrichment Consolidation combines the set of the pathways enriched for the signature gene list through iterative combining of enriched pathways with other pathways with similar signature gene sets; Weighted Consolidation utilizes a Protein-Protein Interaction network based gene-weighting approach that finds clusters of both enriched and non-enriched pathways limited to the experiments' resultant gene list; and finally the de novo Consolidation method uses several measurements of pathway similarity, that finds static pathway clusters independent of any given experiment. We demonstrate that the three consolidation methods provide unified yet different functional insights of a resultant gene set derived from a genome-wide profiling experiment. Results from the methods are presented, demonstrating their applications in biological studies and comparing with a pathway web-based framework that also combines several pathway databases. Additionally a web-based consolidation framework that encompasses all three methods discussed in this paper, Pathway Distiller (http://cbbiweb.uthscsa.edu/PathwayDistiller), is established to allow

Carbon-On-Carbon Manufacturing

Science.gov (United States)

Mungas, Gregory S. (Inventor); Buchanan, Larry (Inventor); Banzon, Jr., Jose T. (Inventor)

2017-01-01

The presently disclosed technology relates to carbon-on-carbon (C/C) manufacturing techniques and the resulting C/C products. One aspect of the manufacturing techniques disclosed herein utilizes two distinct curing operations that occur at different times and/or using different temperatures. The resulting C/C products are substantially non-porous, even though the curing operation(s) substantially gasify a liquid carbon-entrained filler material that saturates a carbon fabric that makes up the C/C products.

The association between donor genetic variations in one-carbon metabolism pathway genes and hepatitis B recurrence after liver transplantation.

Science.gov (United States)

Lu, Di; Zhuo, Jianyong; Yang, Modan; Wang, Chao; Linhui, Pan; Xie, Haiyang; Xu, Xiao; Zheng, Shusen

2018-04-05

Hepatitis B recurrence adversely affects patients' survival after liver transplantation. This study aims to find association between donor gene variations of one carbon metabolism and post-transplant hepatitis B recurrence. This study enrolled 196 patients undergoing liver transplantation for HBV related end-stage liver diseases. We detected 11 single nucleotide polymorphisms (SNP) of 7 one-carbon metabolism pathway genes (including MTHFR, MTR, MTRR, ALDH1L1, GART, SHMT1 and CBS) in donor livers and analyzed their association with HBV reinfection after liver transplantation. Hepatitis B recurrence was observed in 19 of the 196 patients (9.7%) undergoing liver transplantation. Hepatitis B recurrence significantly affected post-transplant survival in the 196 patients (p = 0.018), and correlate with tumor recurrence in the subgroup of HCC patients (n = 99, p = 0.006). Among the 11 SNPs, donor liver mutation in rs1979277 (G > A) was adversely associated with post-transplant hepatitis B recurrence (p = 0.042). In the subgroup of HCC patients, survival analysis showed donor liver mutations in rs1801133 (G > A) and rs1979277 (G > A) were risk factors for hepatitis B recurrence (p B recurrence in non-HCC patients (n = 97, p > 0.05). Hepatitis B recurrence impaired post-transplant survival. Donor liver genetic variations in one-carbon metabolism pathway genes were significantly associated with post-transplant hepatitis B recurrence. Copyright © 2017. Published by Elsevier B.V.

Comparative TEA for Indirect Liquefaction Pathways to Distillate-Range Fuels via Oxygenated Intermediates

Energy Technology Data Exchange (ETDEWEB)

Tan, Eric; Snowden-Swan, Lesley J.; Talmadge, Michael; Dutta, Abhijit; Jones, Susanne; Ramasamy, Karthikeyan; Gray, Michael; Dagle, Robert; Padmaperuma, Asanga; Gerber, Mark; Sahir, Asad; Tao, Ling; Zhang, Yanan

2017-03-03

This paper presents a comparative techno-economic analysis of five conversion pathways from biomass to gasoline-, jet-, and diesel-range hydrocarbons via indirect liquefaction with specific focus on pathways utilizing oxygenated intermediates (derived either via thermochemical or biochemical conversion steps). The four emerging pathways of interest are compared with one conventional pathway (Fischer-Tropsch) for the production of the hydrocarbon blendstocks. The processing steps of the four emerging pathways include: biomass-to-syngas via indirect gasification, gas cleanup, conversion of syngas to alcohols/oxygenates, followed by conversion of alcohols/oxygenates to hydrocarbon blendstocks via dehydration, oligomerization, and hydrogenation. We show that the emerging pathways via oxygenated intermediates have the potential to be cost competitive with the conventional Fischer-Tropsch process. The evaluated pathways and the benchmark process generally exhibit similar fuel yields and carbon conversion efficiencies. The resulting minimum fuel selling prices are comparable to the benchmark at approximately $3.60 per gallon-gasoline equivalent, with potential for two new pathways to be more economically competitive. Additionally, the coproduct values can play an important role in the economics of the processes with oxygenated intermediates derived via syngas fermentation. Major cost drivers for the integrated processes are tied to achievable fuel yields and conversion efficiency of the intermediate steps, i.e., the production of oxygenates/alcohols from syngas and the conversion of oxygenates/alcohols to hydrocarbon fuels.

Pyrolysis of chromium rich tanning industrial wastes and utilization of carbonized wastes in metallurgical process.

Science.gov (United States)

Tôrres Filho, Artur; Lange, Liséte Celina; de Melo, Gilberto Caldeira Bandeira; Praes, Gustavo Eduardo

2016-02-01

Pyrolysis is the thermal degradation of organic material in oxygen-free or very lean oxygen atmosphere. This study evaluates the use of pyrolysis for conversion of leather wastes from chromium tanning processes into Carbonized Leather Residues (CLR), and the utilization of CLR in metallurgical processes through the production of iron ore pellets. CLR was used to replace mineral coal in proportions of 10% and 25% on fixed carbon basis content in the mixtures for pellets preparation. Experimental conversions were performed on a pilot scale pyrolysis plant and a pelletizing reactor of the "pot grate" type. The results demonstrated the technical feasibility of using the charcoal product from animal origin as an energy source, with recovery of up to 76.47% of chromium contained in CLR in the final produced of iron ore pellets. Pellets with 25% replacement of fixed carbon in the coal showed an enhanced compressive strength, with an average value of 344kgfpellet(-1), compared to 300kgfpellet(-1) for standard produced pellets. Copyright © 2015. Published by Elsevier Ltd.

Metabolic Pathways Involved in Carbon Dioxide Enhanced Heat Tolerance in Bermudagrass

Directory of Open Access Journals (Sweden)

Jingjin Yu

2017-09-01

Full Text Available Global climate changes involve elevated temperature and CO2 concentration, imposing significant impact on plant growth of various plant species. Elevated temperature exacerbates heat damages, but elevated CO2 has positive effects on promoting plant growth and heat tolerance. The objective of this study was to identify metabolic pathways affected by elevated CO2 conferring the improvement of heat tolerance in a C4 perennial grass species, bermudagrass (Cynodon dactylon Pers.. Plants were planted under either ambient CO2 concentration (400 μmol⋅mol-1 or elevated CO2 concentration (800 μmol⋅mol-1 and subjected to ambient temperature (30/25°C, day/night or heat stress (45/40°C, day/night. Elevated CO2 concentration suppressed heat-induced damages and improved heat tolerance in bermudagrass. The enhanced heat tolerance under elevated CO2 was attributed to some important metabolic pathways during which proteins and metabolites were up-regulated, including light reaction (ATP synthase subunit and photosystem I reaction center subunit and carbon fixation [(glyceraldehyde-3-phosphate dehydrogenase, GAPDH, fructose-bisphosphate aldolase, phosphoglycerate kinase, sedoheptulose-1,7-bisphosphatase and sugars of photosynthesis, glycolysis (GAPDH, glucose, fructose, and galactose and TCA cycle (pyruvic acid, malic acid and malate dehydrogenase of respiration, amino acid metabolism (aspartic acid, methionine, threonine, isoleucine, lysine, valine, alanine, and isoleucine as well as the GABA shunt (GABA, glutamic acid, alanine, proline and 5-oxoproline. The up-regulation of those metabolic processes by elevated CO2 could at least partially contribute to the improvement of heat tolerance in perennial grass species.

Utilization of oil palm fronds in producing activated carbon using Na2CO3 as an activator

Science.gov (United States)

Maulina, S.; Anwari, FN

2018-02-01

Oil Palm Frond is a waste in palm oil plantations that have the potential to be processed into more valuable products. This possibility is because of the presence of cellulose, hemicellulose, and lignin in oil palm fronds. Therefore, this study aimed to utilize oil palm fronds in manufacturing of activated carbon through pyrolysis and impregnation that meets the requirements of the Industrial National Standard 06-3730-1995. The palm-fringed oil palm fronds were pyrolyzed in reactors at 150°C, 200°C, and 250°C for 60 minutes. Subsequently, the charcoal produced from the pyrolysis was smoothed with a ball mill, sieved with a size of 140 meshes, and impregnated using a Sodium Carbonate (Na2CO3) for 24 hours at a concentration of 0 %, 2.5%, 5%, and 7.5 % (w/v). The activated carbon has 35.13% of charcoal yield, 8.6% of water content, 14.25% of ash content, 24.75% of volatile matter, 72.75% of fixed carbon, and 492.29 of iodine number. Moreover, SEM analysis indicated that activated carbon porous are coarse and distributed.

New Pathways and Metrics for Enhanced, Reversible Hydrogen Storage in Boron-Doped Carbon Nanospaces

Energy Technology Data Exchange (ETDEWEB)

Pfeifer, Peter [University of Missouri; Wexler, Carlos [University of Missouri; Hawthorne, M. Frederick [University of Missouri; Lee, Mark W. [University of Missouri; Jalistegi, Satish S. [University of Missouri

2014-08-14

This project, since its start in 2007—entitled “Networks of boron-doped carbon nanopores for low-pressure reversible hydrogen storage” (2007-10) and “New pathways and metrics for enhanced, reversible hydrogen storage in boron-doped carbon nanospaces” (2010-13)—is in support of the DOE's National Hydrogen Storage Project, as part of the DOE Hydrogen and Fuel Cells Program’s comprehensive efforts to enable the widespread commercialization of hydrogen and fuel cell technologies in diverse sectors of the economy. Hydrogen storage is widely recognized as a critical enabling technology for the successful commercialization and market acceptance of hydrogen powered vehicles. Storing sufficient hydrogen on board a wide range of vehicle platforms, at energy densities comparable to gasoline, without compromising passenger or cargo space, remains an outstanding technical challenge. Of the main three thrust areas in 2007—metal hydrides, chemical hydrogen storage, and sorption-based hydrogen storage—sorption-based storage, i.e., storage of molecular hydrogen by adsorption on high-surface-area materials (carbons, metal-organic frameworks, and other porous organic networks), has emerged as the most promising path toward achieving the 2017 DOE storage targets of 0.055 kg H2/kg system (“5.5 wt%”) and 0.040 kg H2/liter system. The objective of the project is to develop high-surface-area carbon materials that are boron-doped by incorporation of boron into the carbon lattice at the outset, i.e., during the synthesis of the material. The rationale for boron-doping is the prediction that boron atoms in carbon will raise the binding energy of hydro- gen from 4-5 kJ/mol on the undoped surface to 10-14 kJ/mol on a doped surface, and accordingly the hydro- gen storage capacity of the material. The mechanism for the increase in binding energy is electron donation from H2 to electron-deficient B atoms, in the form of sp2 boron-carbon bonds. Our team is proud to have

Methane-rich water induces cucumber adventitious rooting through heme oxygenase1/carbon monoxide and Ca(2+) pathways.

Science.gov (United States)

Cui, Weiti; Qi, Fang; Zhang, Yihua; Cao, Hong; Zhang, Jing; Wang, Ren; Shen, Wenbiao

2015-03-01

Methane-rich water triggered adventitious rooting by regulating heme oxygenase1/carbon monoxide and calcium pathways in cucumber explants. Heme oxygenase1/carbon monoxide (HO1/CO) and calcium (Ca(2+)) were reported as the downstream signals in auxin-induced cucumber adventitious root (AR) formation. Here, we observed that application of methane-rich water (MRW; 80% saturation) obviously induced AR formation in IAA-depleted cucumber explants. To address the universality, we checked adventitious rooting in soybean and mung bean explants, and found that MRW (50 and 10% saturation, respectively) exhibited the similar inducing results. To further determine if the HO1/CO system participated in MRW-induced adventitious rooting, MRW, HO1 inducer hemin, its activity inhibitor zinc protoporphyrin IX (ZnPP), and its catalytic by-products CO, bilirubin, and Fe(2+) were used to detect their effects on cucumber adventitious rooting in IAA-depleted explants. Subsequent results showed that MRW-induced adventitious rooting was blocked by ZnPP and further reversed by 20% saturation CO aqueous solution. However, the other two by-products of HO1, bilirubin and Fe(2+), failed to induce AR formation. Above responses were consistent with the MRW-induced increases of HO1 transcript and corresponding protein level. Further molecular evidence indicted that expression of marker genes, including auxin signaling-related genes and cell cycle regulatory genes, were modulated by MRW alone but blocked by the cotreatment with ZnPP, the latter of which could be significantly rescued by the addition of CO. By using the Ca(2+)-channel blocker and Ca(2+) chelator, the involvement of Ca(2+) pathway in MRW-induced adventitious rooting was also suggested. Together, our results indicate that MRW might serve as a stimulator of adventitious rooting, which was partially mediated by HO1/CO and Ca(2+) pathways.

Selection criteria utilized for hyperbaric oxygen treatment of carbon monoxide poisoning.

Science.gov (United States)

Hampson, N B; Dunford, R G; Kramer, C C; Norkool, D M

1995-01-01

Medical directors of North American hyperbaric oxygen (HBO) facilities were surveyed to assess selection criteria applied for treatment of acute carbon monoxide (CO) poisoning within the hyperbaric medicine community. Responses were received from 85% of the 208 facilities in the United States and Canada. Among responders, 89 monoplace and 58 multiplace chamber facilities treat acute CO poisoning, managing a total of 2,636 patients in 1992. A significant majority of facilities treat CO-exposed patients with coma (98%), transient loss of consciousness (LOC) (77%), ischemic changes on electrocardiogram (91%), focal neurologic deficits (94%), or abnormal psychometric testing (91%), regardless of carboxyhemoglobin (COHb) level. Although 92% would use HBO for a patient presenting with headache, nausea, and COHb 40%, only 62% of facilities utilize a specified minimum COHb level as the sole criterion for HBO therapy of an asymptomatic patient. When COHb is used as an independent criterion to determine HBO treatment, the level utilized varies widely between institutions. Half of responding facilities place limits on the delay to treatment for patients with only transient LOC. Time limits are applied less often in cases with persistent neurologic deficits. While variability exists, majority opinions can be derived for many patient selection criteria regarding the use of HBO in acute CO poisoning.

Five phosphonate operon gene products as components of a multi-subunit complex of the carbon-phosphorus lyase pathway

DEFF Research Database (Denmark)

Jochimsen, Bjarne; Lolle, Signe; McSorley, Fern R.

2011-01-01

Organophosphonate utilization by Escherichia coli requires the 14 cistrons of the phnCDEFGHIJKLMNOP operon, of which the carbon-phosphorus lyase has been postulated to consist of the seven polypeptides specified by phnG to phnM. A 5,660-bp DNA fragment encompassing phnGHIJKLM is cloned, followed...

Engineering an Obligate Photoautotrophic Cyanobacterium to Utilize Glycerol for Growth and Chemical Production.

Science.gov (United States)

Kanno, Masahiro; Atsumi, Shota

2017-01-20

Cyanobacteria have attracted much attention as a means to directly recycle carbon dioxide into valuable chemicals that are currently produced from petroleum. However, the titers and productivities achieved are still far below the level required in industry. To make a more industrially applicable production scheme, glycerol, a byproduct of biodiesel production, can be used as an additional carbon source for photomixotrophic chemical production. Glycerol is an ideal candidate due to its availability and low cost. In this study, we found that a heterologous glycerol respiratory pathway enabled Synechococcus elongatus PCC 7942 to utilize extracellular glycerol. The engineered strain produced 761 mg/L of 2,3-butanediol in 48 h with a 290% increase over the control strain under continuous light conditions. Glycerol supplementation also allowed for continuous cell growth and 2,3-butanediol production in diurnal light conditions. These results highlight the potential of glycerol as an additional carbon source for photomixotrophic chemical production in cyanobacteria.

Utilization of calcium carbonate particles from eggshell waste as coating pigments for ink-jet printing paper.

Science.gov (United States)

Yoo, Sukjoon; Hsieh, Jeffery S; Zou, Peter; Kokoszka, John

2009-12-01

The effective treatment and utilization of biowaste have been emphasized in our society for environmental and economic concerns. Recently, the eggshell waste in the poultry industry has been highlighted because of its reclamation potential. This study presents an economical treatment process to recover useful bioproducts from eggshell waste and their utilization in commercial products. We developed the dissolved air floatation (DAF) separation unit, which successfully recovered 96% of eggshell membrane and 99% of eggshell calcium carbonate (ECC) particles from eggshell waste within 2 h of operation. The recovered ECC particles were utilized as coating pigments for ink-jet printing paper and their impact on the ink density and paper gloss were investigated. The addition of the ECC particles as coating pigments enhances the optical density of cyan, magenta and yellow inks while decreasing the black ink density and the gloss of the coated paper.

Bulk segregant analysis by high-throughput sequencing reveals a novel xylose utilization gene from Saccharomyces cerevisiae.

Directory of Open Access Journals (Sweden)

Jared W Wenger

2010-05-01

Full Text Available Fermentation of xylose is a fundamental requirement for the efficient production of ethanol from lignocellulosic biomass sources. Although they aggressively ferment hexoses, it has long been thought that native Saccharomyces cerevisiae strains cannot grow fermentatively or non-fermentatively on xylose. Population surveys have uncovered a few naturally occurring strains that are weakly xylose-positive, and some S. cerevisiae have been genetically engineered to ferment xylose, but no strain, either natural or engineered, has yet been reported to ferment xylose as efficiently as glucose. Here, we used a medium-throughput screen to identify Saccharomyces strains that can increase in optical density when xylose is presented as the sole carbon source. We identified 38 strains that have this xylose utilization phenotype, including strains of S. cerevisiae, other sensu stricto members, and hybrids between them. All the S. cerevisiae xylose-utilizing strains we identified are wine yeasts, and for those that could produce meiotic progeny, the xylose phenotype segregates as a single gene trait. We mapped this gene by Bulk Segregant Analysis (BSA using tiling microarrays and high-throughput sequencing. The gene is a putative xylitol dehydrogenase, which we name XDH1, and is located in the subtelomeric region of the right end of chromosome XV in a region not present in the S288c reference genome. We further characterized the xylose phenotype by performing gene expression microarrays and by genetically dissecting the endogenous Saccharomyces xylose pathway. We have demonstrated that natural S. cerevisiae yeasts are capable of utilizing xylose as the sole carbon source, characterized the genetic basis for this trait as well as the endogenous xylose utilization pathway, and demonstrated the feasibility of BSA using high-throughput sequencing.

Feed in summer, rest in winter: microbial carbon utilization in forest topsoil.

Science.gov (United States)

Žifčáková, Lucia; Větrovský, Tomáš; Lombard, Vincent; Henrissat, Bernard; Howe, Adina; Baldrian, Petr

2017-09-18

Evergreen coniferous forests contain high stocks of organic matter. Significant carbon transformations occur in litter and soil of these ecosystems, making them important for the global carbon cycle. Due to seasonal allocation of photosynthates to roots, carbon availability changes seasonally in the topsoil. The aim of this paper was to describe the seasonal differences in C source utilization and the involvement of various members of soil microbiome in this process. Here, we show that microorganisms in topsoil encode a diverse set of carbohydrate-active enzymes, including glycoside hydrolases and auxiliary enzymes. While the transcription of genes encoding enzymes degrading reserve compounds, such as starch or trehalose, was high in soil in winter, summer was characterized by high transcription of ligninolytic and cellulolytic enzymes produced mainly by fungi. Fungi strongly dominated the transcription in litter and an equal contribution of bacteria and fungi was found in soil. The turnover of fungal biomass appeared to be faster in summer than in winter, due to high activity of enzymes targeting its degradation, indicating fast growth in both litter and soil. In each enzyme family, hundreds to thousands of genes were typically transcribed simultaneously. Seasonal differences in the transcription of glycoside hydrolases and auxiliary enzyme genes are more pronounced in soil than in litter. Our results suggest that mainly fungi are involved in decomposition of recalcitrant biopolymers in summer, while bacteria replace them in this role in winter. Transcripts of genes encoding enzymes targeting plant biomass biopolymers, reserve compounds and fungal cell walls were especially abundant in the coniferous forest topsoil.

Direct Carbon Fuel Cell System Utilizing Solid Carbonaceous Fuels

Energy Technology Data Exchange (ETDEWEB)

Turgut Gur

2010-04-30

This 1-year project has achieved most of its objective and successfully demonstrated the viability of the fluidized bed direct carbon fuel cell (FB-DCFC) approach under development by Direct Carbon technologies, LLC, that utilizes solid carbonaceous fuels for power generation. This unique electrochemical technology offers high conversion efficiencies, produces proportionately less CO{sub 2} in capture-ready form, and does not consume or require water for gasification. FB-DCFC employs a specialized solid oxide fuel cell (SOFC) arrangement coupled to a Boudouard gasifier where the solid fuel particles are fluidized and reacted by the anode recycle gas CO{sub 2}. The resulting CO is electrochemically oxidized at the anode. Anode supported SOFC structures employed a porous Ni cermet anode layer, a dense yttria stabilized zirconia membrane, and a mixed conducting porous perovskite cathode film. Several kinds of untreated solid fuels (carbon and coal) were tested in bench scale FBDCFC prototypes for electrochemical performance and stability testing. Single cells of tubular geometry with active areas up to 24 cm{sup 2} were fabricated. The cells achieved high power densities up to 450 mW/cm{sup 2} at 850 C using a low sulfur Alaska coal char. This represents the highest power density reported in the open literature for coal based DCFC. Similarly, power densities up to 175 mW/cm{sup 2} at 850 C were demonstrated with carbon. Electrical conversion efficiencies for coal char were experimentally determined to be 48%. Long-term stability of cell performance was measured under galvanostatic conditions for 375 hours in CO with no degradation whatsoever, indicating that carbon deposition (or coking) does not pose any problems. Similar cell stability results were obtained in coal char tested for 24 hours under galvanostatic conditions with no sign of sulfur poisoning. Moreover, a 50-cell planar stack targeted for 1 kW output was fabricated and tested in 95% CO (balance CO{sub 2

Tin-Containing Silicates: Identification of a Glycolytic Pathway via 3-Deoxyglucosone

DEFF Research Database (Denmark)

Tolborg, Søren; Meier, Sebastian; Sádaba, I.

2016-01-01

a cascade of four to five sequential steps. Currently, there is a limited understanding of the competing glycolytic pathways within these systems. Here we identify dehydration of glucose to 3-deoxyglucosone as an important pathway that occurs in addition to retro-aldol reaction of hexoses when using tin......-containing silicates. It is possible to influence the relative carbon flux through these pathways by controlling the amount of alkali metal salts present in the reaction mixture. In the absence of added potassium carbonate, at least 15–30% carbon flux via 3-deoxyglucosone is observed. Addition of just a few ppm...

Micrometeorological Technique for Monitoring of Geological Carbon Capture, Utilization and Storage: Methodology, Workflow and Resources

Science.gov (United States)

Burba, G. G.; Madsen, R.; Feese, K.

2013-12-01

The eddy covariance (EC) method is a micrometeorological technique for direct high-speed measurements of the transport of gases and energy between land or water surfaces and the atmosphere [1]. This method allows for observations of gas transport scales from 20-40 times per second to multiple years, represents gas exchange integrated over a large area, from hundreds of square meters to tens of square kilometres, and corresponds to gas exchange from the entire surface, including canopy, and soil or water layers. Gas fluxes, emission and exchange rates are characterized from single-point in situ measurements using permanent or mobile towers, or moving platforms such as automobiles, helicopters, airplanes, etc. Presently, over 600 eddy covariance stations are in operation in over 120 countries [1]. EC is now recognized as an effective method in regulatory and industrial applications, including CCUS [2-10]. Emerging projects utilize EC to continuously monitor large areas before and after the injections, to locate and quantify leakages where CO2 may escape from the subsurface, to improve storage efficiency, and for other CCUS characterizations [5-10]. Although EC is one of the most direct and defensible micrometeorological techniques measuring gas emission and transport, and complete automated stations and processing are readily available, the method is mathematically complex, and requires careful setup and execution specific to the site and project. With this in mind, step-by-step instructions were created in [1] to introduce a novice to the EC method, and to assist in further understanding of the method through more advanced references. In this presentation we provide brief highlights of the eddy covariance method, its application to geological carbon capture, utilization and storage, key requirements, instrumentation and software, and review educational resources particularly useful for carbon sequestration research. References: [1] Burba G. Eddy Covariance Method

Designing management strategies for carbon dioxide storage and utilization under uncertainty using inexact modelling

Science.gov (United States)

Wang, Yu; Fan, Jie; Xu, Ye; Sun, Wei; Chen, Dong

2017-06-01

Effective application of carbon capture, utilization and storage (CCUS) systems could help to alleviate the influence of climate change by reducing carbon dioxide (CO2) emissions. The research objective of this study is to develop an equilibrium chance-constrained programming model with bi-random variables (ECCP model) for supporting the CCUS management system under random circumstances. The major advantage of the ECCP model is that it tackles random variables as bi-random variables with a normal distribution, where the mean values follow a normal distribution. This could avoid irrational assumptions and oversimplifications in the process of parameter design and enrich the theory of stochastic optimization. The ECCP model is solved by an equilibrium change-constrained programming algorithm, which provides convenience for decision makers to rank the solution set using the natural order of real numbers. The ECCP model is applied to a CCUS management problem, and the solutions could be useful in helping managers to design and generate rational CO2-allocation patterns under complexities and uncertainties.

Effect of large aspect ratio of biomass particles on carbon burnout in a utility boiler

Energy Technology Data Exchange (ETDEWEB)

D. Gera; M.P. Mathur; M.C. Freeman; Allen Robinson [Fluent, Inc./NETL, Morgantown, WV (United States)

2002-12-01

This paper reports on the development and validation of comprehensive combustion sub models that include the effect of large aspect ratio of biomass (switchgrass) particles on carbon burnout and temperature distribution inside the particles. Temperature and carbon burnout data are compared from two different models that are formulated by assuming (i) the particles are cylindrical and conduct heat internally, and (ii) the particles are spherical without internal heat conduction, i.e., no temperature gradient exists inside the particle. It was inferred that the latter model significantly underpredicted the temperature of the particle and, consequently, the burnout. Additionally, some results from cofiring biomass (10% heat input) with pulverized coal (90% heat input) are compared with the pulverized coal (100% heat input) simulations and coal experiments in a tangentially fired 150 MW{sub e} utility boiler. 26 refs., 7 figs., 4 tabs.

Comprehensive evaluation of one-carbon metabolism pathway gene variants and renal cell cancer risk.

Directory of Open Access Journals (Sweden)

Todd M Gibson

Full Text Available Folate and one-carbon metabolism are linked to cancer risk through their integral role in DNA synthesis and methylation. Variation in one-carbon metabolism genes, particularly MTHFR, has been associated with risk of a number of cancers in epidemiologic studies, but little is known regarding renal cancer.Tag single nucleotide polymorphisms (SNPs selected to produce high genomic coverage of 13 gene regions of one-carbon metabolism (ALDH1L1, BHMT, CBS, FOLR1, MTHFR, MTR, MTRR, SHMT1, SLC19A1, TYMS and the closely associated glutathione synthesis pathway (CTH, GGH, GSS were genotyped for 777 renal cell carcinoma (RCC cases and 1,035 controls in the Central and Eastern European Renal Cancer case-control study. Associations of individual SNPs (n = 163 with RCC risk were calculated using unconditional logistic regression adjusted for age, sex and study center. Minimum p-value permutation (Min-P tests were used to identify gene regions associated with risk, and haplotypes were evaluated within these genes.The strongest associations with RCC risk were observed for SLC19A1 (P(min-P = 0.03 and MTHFR (P(min-P = 0.13. A haplotype consisting of four SNPs in SLC19A1 (rs12483553, rs2838950, rs2838951, and rs17004785 was associated with a 37% increased risk (p = 0.02, and exploratory stratified analysis suggested the association was only significant among those in the lowest tertile of vegetable intake.To our knowledge, this is the first study to comprehensively examine variation in one-carbon metabolism genes in relation to RCC risk. We identified a novel association with SLC19A1, which is important for transport of folate into cells. Replication in other populations is required to confirm these findings.

Ensemble Modeling for Robustness Analysis in engineering non-native metabolic pathways.

Science.gov (United States)

Lee, Yun; Lafontaine Rivera, Jimmy G; Liao, James C

2014-09-01

Metabolic pathways in cells must be sufficiently robust to tolerate fluctuations in expression levels and changes in environmental conditions. Perturbations in expression levels may lead to system failure due to the disappearance of a stable steady state. Increasing evidence has suggested that biological networks have evolved such that they are intrinsically robust in their network structure. In this article, we presented Ensemble Modeling for Robustness Analysis (EMRA), which combines a continuation method with the Ensemble Modeling approach, for investigating the robustness issue of non-native pathways. EMRA investigates a large ensemble of reference models with different parameters, and determines the effects of parameter drifting until a bifurcation point, beyond which a stable steady state disappears and system failure occurs. A pathway is considered to have high bifurcational robustness if the probability of system failure is low in the ensemble. To demonstrate the utility of EMRA, we investigate the bifurcational robustness of two synthetic central metabolic pathways that achieve carbon conservation: non-oxidative glycolysis and reverse glyoxylate cycle. With EMRA, we determined the probability of system failure of each design and demonstrated that alternative designs of these pathways indeed display varying degrees of bifurcational robustness. Furthermore, we demonstrated that target selection for flux improvement should consider the trade-offs between robustness and performance. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Fungi, bacteria and soil pH: the oxalate-carbonate pathway as a model for metabolic interaction.

Science.gov (United States)

Martin, Gaëtan; Guggiari, Matteo; Bravo, Daniel; Zopfi, Jakob; Cailleau, Guillaume; Aragno, Michel; Job, Daniel; Verrecchia, Eric; Junier, Pilar

2012-11-01

The oxalate-carbonate pathway involves the oxidation of calcium oxalate to low-magnesium calcite and represents a potential long-term terrestrial sink for atmospheric CO(2). In this pathway, bacterial oxalate degradation is associated with a strong local alkalinization and subsequent carbonate precipitation. In order to test whether this process occurs in soil, the role of bacteria, fungi and calcium oxalate amendments was studied using microcosms. In a model system with sterile soil amended with laboratory cultures of oxalotrophic bacteria and fungi, the addition of calcium oxalate induced a distinct pH shift and led to the final precipitation of calcite. However, the simultaneous presence of bacteria and fungi was essential to drive this pH shift. Growth of both oxalotrophic bacteria and fungi was confirmed by qPCR on the frc (oxalotrophic bacteria) and 16S rRNA genes, and the quantification of ergosterol (active fungal biomass) respectively. The experiment was replicated in microcosms with non-sterilized soil. In this case, the bacterial and fungal contribution to oxalate degradation was evaluated by treatments with specific biocides (cycloheximide and bronopol). Results showed that the autochthonous microflora oxidized calcium oxalate and induced a significant soil alkalinization. Moreover, data confirmed the results from the model soil showing that bacteria are essentially responsible for the pH shift, but require the presence of fungi for their oxalotrophic activity. The combined results highlight that the interaction between bacteria and fungi is essential to drive metabolic processes in complex environments such as soil. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

Biodegradation and utilization of 4-n-nonylphenol by Aspergillus versicolor as a sole carbon and energy source

International Nuclear Information System (INIS)

Krupiński, Mariusz; Janicki, Tomasz; Pałecz, Bartłomiej; Długoński, Jerzy

2014-01-01

Highlights: • A. versicolor is able to degrade 4-n-NP as the sole source of carbon and energy. • 4-n-NP removal by A. versicolor was accompanied by the formation of metabolites. • Radioactive experiments show complete 4-n-NP mineralization by A. versicolor. • 4-n-NP initiates heat production in the A. versicolor spores. - Abstract: 4-n-Nonylphenol (4-n-NP) is an environmental pollutant with endocrine-disrupting activities that is formed during the degradation of nonylphenol polyethoxylates, which are widely used as surfactants. Utilization of 4-n-NP by the filamentous fungus Aspergillus versicolor as the sole carbon and energy source was investigated. By means of gas chromatography–mass spectrometry, we showed that in the absence of any carbon source other than 4-n-NP in the medium, A. versicolor completely removed the xenobiotic (100 mg L −1 ) after 3 d of cultivation. Moreover, mass spectrometric analysis of intracellular extracts led to the identification of eight intermediates. The mineralization of the xenobiotic in cultures supplemented with 4-n-NP [ring- 14 C(U)] as a growth substrate was also assessed. After 3 d of incubation, approximately 50% of the initially applied radioactivity was recovered in the form of 14 CO 2 , proving that this xenobiotic was completely metabolized and utilized by A. versicolor as a carbon source. Based on microscopic analysis, A. versicolor is capable of germinating spores under such conditions. To confirm these observations, a microcalorimetric method was used. The results show that even the highest amount of 4-n-NP initiates heat production in the fungal samples, proving that metabolic processes were affected by the use of 4-n-NP as an energetic substrate

Biodegradation and utilization of 4-n-nonylphenol by Aspergillus versicolor as a sole carbon and energy source

Energy Technology Data Exchange (ETDEWEB)

Krupiński, Mariusz; Janicki, Tomasz [Department of Industrial Microbiology and Biotechnology, University of Lodz, Banacha 12/16, 90-237 Łódź (Poland); Pałecz, Bartłomiej [Department of Physical Chemistry, University of Lodz, Pomorska 165, 90-236 Łódź (Poland); Długoński, Jerzy, E-mail: jdlugo@biol.uni.lodz.pl [Department of Industrial Microbiology and Biotechnology, University of Lodz, Banacha 12/16, 90-237 Łódź (Poland)

2014-09-15

Highlights: • A. versicolor is able to degrade 4-n-NP as the sole source of carbon and energy. • 4-n-NP removal by A. versicolor was accompanied by the formation of metabolites. • Radioactive experiments show complete 4-n-NP mineralization by A. versicolor. • 4-n-NP initiates heat production in the A. versicolor spores. - Abstract: 4-n-Nonylphenol (4-n-NP) is an environmental pollutant with endocrine-disrupting activities that is formed during the degradation of nonylphenol polyethoxylates, which are widely used as surfactants. Utilization of 4-n-NP by the filamentous fungus Aspergillus versicolor as the sole carbon and energy source was investigated. By means of gas chromatography–mass spectrometry, we showed that in the absence of any carbon source other than 4-n-NP in the medium, A. versicolor completely removed the xenobiotic (100 mg L{sup −1}) after 3 d of cultivation. Moreover, mass spectrometric analysis of intracellular extracts led to the identification of eight intermediates. The mineralization of the xenobiotic in cultures supplemented with 4-n-NP [ring-{sup 14}C(U)] as a growth substrate was also assessed. After 3 d of incubation, approximately 50% of the initially applied radioactivity was recovered in the form of {sup 14}CO{sub 2}, proving that this xenobiotic was completely metabolized and utilized by A. versicolor as a carbon source. Based on microscopic analysis, A. versicolor is capable of germinating spores under such conditions. To confirm these observations, a microcalorimetric method was used. The results show that even the highest amount of 4-n-NP initiates heat production in the fungal samples, proving that metabolic processes were affected by the use of 4-n-NP as an energetic substrate.

LFTR: in search of the ideal pathway to thorium utilization-development program and current status

International Nuclear Information System (INIS)

Soon, Benjamin

2015-01-01

Thorium has gained substantial attention as a potential energy source that could rival and eventually replace fossil fuels as humanity's primary energy source. This could not have come at a more opportune time as concerns about global climate change from CO 2 emissions and the approaching spectre of finite fossil fuel resources create serious challenges for the continuation of our advanced industrial societies, which are reliant on readily available and affordable energy. Thorium also potentially represents the catalyst with which the nuclear industry could reinvent itself and finally gain widespread public acceptance. There are many opinions on how to utilize thorium as a fuel, but the question of what constitutes an 'ideal' pathway has mostly been under-emphasized. Many specific characteristics of the thorium fuel cycle can differ significantly depending on the conditions and methodologies of utilization; characteristics such as safety, efficiency, waste profile and volume, and fissile protection can vary greatly according to reactor design and utilization philosophy. With thorium, we have been given an opportunity to start over, a blank slate. Therefore, in imagining the 'Thorium Economy' to come, it behoves the scientific and engineering communities to consider the most 'elegant' solution physically possible-what constitutes the 'ideal' and is it possible to reconcile it with what is both economically and technically practical? The characteristics desired of an 'ideal' nuclear reactor, in the areas of safety, efficiency, economy, and sustainability, and the 5 key design choices that could enable such a reactor will be discussed. This will be followed by an overview of the Liquid Fluoride Thorium Reactor, a 2-fluid Molten Salt Reactor currently under development by Flibe Energy in the United States. LFTR is a direct descendant of the MSRE, which was developed at Oak Ridge National Laboratory (ORNL) in the

Metabolite profile analysis reveals functional effects of 28-day vitamin B-6 restriction on one-carbon metabolism and tryptophan catabolic pathways in healthy men and women.

Science.gov (United States)

da Silva, Vanessa R; Rios-Avila, Luisa; Lamers, Yvonne; Ralat, Maria A; Midttun, Øivind; Quinlivan, Eoin P; Garrett, Timothy J; Coats, Bonnie; Shankar, Meena N; Percival, Susan S; Chi, Yueh-Yun; Muller, Keith E; Ueland, Per Magne; Stacpoole, Peter W; Gregory, Jesse F

2013-11-01

Suboptimal vitamin B-6 status, as reflected by low plasma pyridoxal 5'-phosphate (PLP) concentration, is associated with increased risk of vascular disease. PLP plays many roles, including in one-carbon metabolism for the acquisition and transfer of carbon units and in the transsulfuration pathway. PLP also serves as a coenzyme in the catabolism of tryptophan. We hypothesize that the pattern of these metabolites can provide information reflecting the functional impact of marginal vitamin B-6 deficiency. We report here the concentration of major constituents of one-carbon metabolic processes and the tryptophan catabolic pathway in plasma from 23 healthy men and women before and after a 28-d controlled dietary vitamin B-6 restriction (restriction yielded increased cystathionine (53% pre- and 76% postprandial; P restriction yielded lower kynurenic acid (22% pre- and 20% postprandial; P restriction and multilevel partial least squares-discriminant analysis supported this conclusion. Thus, plasma concentrations of creatine, cystathionine, kynurenic acid, and 3-hydroxykynurenine jointly reveal effects of vitamin B-6 restriction on the profiles of one-carbon and tryptophan metabolites and serve as biomarkers of functional effects of marginal vitamin B-6 deficiency.

Non-Smad pathways in TGF-β signaling

OpenAIRE

Zhang, Ying E

2009-01-01

Transforming growth factor-β utilizes a multitude of intracellular signaling pathways in addition to Smads to regulate a wide array of cellular functions. These non-canonical, non-Smad pathways are activated directly by ligand-occupied receptors to reinforce, attenuate, or otherwise modulate downstream cellular responses. These non-Smad pathways include various branches of MAP kinase pathways, Rho-like GTPase signaling pathways, and phosphatidylinositol-3-kinase/AKT pathways. This review focu...

Solid oxide fuel cell bi-layer anode with gadolinia-doped ceria for utilization of solid carbon fuel

Energy Technology Data Exchange (ETDEWEB)

Kellogg, Isaiah D. [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, 290A Toomey Hall, 400 West 13th Street, Rolla, MO 65409 (United States); Department of Materials Science and Engineering, Missouri University of Science and Technology, 223 McNutt Hall, 1400 N. Bishop, Rolla, MO 65409 (United States); Koylu, Umit O. [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, 290A Toomey Hall, 400 West 13th Street, Rolla, MO 65409 (United States); Dogan, Fatih [Department of Materials Science and Engineering, Missouri University of Science and Technology, 223 McNutt Hall, 1400 N. Bishop, Rolla, MO 65409 (United States)

2010-11-01

Pyrolytic carbon was used as fuel in a solid oxide fuel cell (SOFC) with a yttria-stabilized zirconia (YSZ) electrolyte and a bi-layer anode composed of nickel oxide gadolinia-doped ceria (NiO-GDC) and NiO-YSZ. The common problems of bulk shrinkage and emergent porosity in the YSZ layer adjacent to the GDC/YSZ interface were avoided by using an interlayer of porous NiO-YSZ as a buffer anode layer between the electrolyte and the NiO-GDC primary anode. Cells were fabricated from commercially available component powders so that unconventional production methods suggested in the literature were avoided, that is, the necessity of glycine-nitrate combustion synthesis, specialty multicomponent oxide powders, sputtering, or chemical vapor deposition. The easily-fabricated cell was successfully utilized with hydrogen and propane fuels as well as carbon deposited on the anode during the cyclic operation with the propane. A cell of similar construction could be used in the exhaust stream of a diesel engine to capture and utilize soot for secondary power generation and decreased particulate pollution without the need for filter regeneration. (author)

Global zero-carbon energy pathways using viable mixes of nuclear and renewables

International Nuclear Information System (INIS)

Hong, Sanghyun; Bradshaw, Corey J.A.; Brook, Barry W.

2015-01-01

Highlights: • A proper mix of nuclear power and renewables achieves sustainable energy future. • A high nuclear share provides cost and land effectiveness compared to nuclear-free. • Only-renewable mix will increase negative economic and environmental impacts. • A deployment of advanced reactor technologies is essential to overcome limitations. - Abstract: What are the most viable global pathways for a major expansion of zero-carbon emissions electricity sources given the diversity of regional technical, socio-political and economic constraints? We modelled a range of zero-emissions energy scenarios across nations that were designed to meet projected final energy demand in 2060, and optimised to derive the best globally aggregated results in terms of minimising costs and land use (a surrogate for environmental impacts). We found that a delayed energy transition to a zero-emissions pathway will decrease investment costs (−$3,431 billion), but increase cumulative CO 2 emissions (additional 696 Gt). A renewable-only scenario would convert >7.4% of the global land area to energy production, whereas a maximum nuclear scenario would affect <0.4% of land area, including mining, spent-fuel storage, and buffer zones. Moreover, a nuclear-free pathway would involve up to a 50% greater cumulative capital investment compared to a high nuclear penetration scenario ($73.7 trillion). However, for some nations with a high current share of renewables and a low projected future energy demand (e.g., Norway), pursuit of a higher nuclear share is suboptimal. In terms of the time frame for replacement of fossil fuels, achieving a global nuclear share of about 50% by 2060 would be a technically and economically plausible target if progressing at a pace of the average historical growth of nuclear power penetration in France from 1970 to 1986 (0.28 MWh person −1 year -1 ). For effective climate-change mitigation, a high penetration of nuclear in association with a nationally

Heterologous Production of an Energy-Conserving Carbon Monoxide Dehydrogenase Complex in the Hyperthermophile Pyrococcus furiosus

Directory of Open Access Journals (Sweden)

Gerrit Jan Schut

2016-01-01

Full Text Available Carbon monoxide (CO is an important intermediate in anaerobic carbon fixation pathways in acetogenesis and methanogenesis. In addition, some anaerobes can utilize CO as an energy source. In the hyperthermophilic archaeon Thermococcus onnurineus, which grows optimally at 80°C, CO oxidation and energy conservation is accomplished by a respiratory complex encoded by a 16-gene cluster containing a carbon monoxide dehydrogenase, a membrane-bound [NiFe]-hydrogenase and a Na+/H+ antiporter module. This complex oxidizes CO, evolves CO2 and H2, and generates a Na+ motive force that is used to conserve energy by a Na+-dependent ATP synthase. Herein we used a bacterial artificial chromosome to insert the 13.2 kb gene cluster encoding the CO-oxidizing respiratory complex of T. onnurineus into the genome of the heterotrophic archaeon, Pyrococcus furiosus, which grows optimally at 100°C. P. furiosus is normally unable to utilize CO, however, the recombinant strain readily oxidized CO and generated H2 at 80°C. Moreover, CO also served as an energy source and allowed the P. furiosus strain to grow with a limiting concentration of sugar or with peptides as the carbon source. Moreover, CO oxidation by P. furiosus was also coupled to the re-utilization, presumably for biosynthesis, of acetate generated by fermentation. The functional transfer of CO utilization between Thermococcus and Pyrococcus species demonstrated herein is representative of the horizontal gene transfer of an environmentally-relevant metabolic capability. The transfer of CO utilizing, hydrogen-producing genetic modules also has applications for biohydrogen production and a CO-based industrial platform for various thermophilic organisms.

Carbon isotope fractionation by anoxygenic phototrophic bacteria in euxinic Lake Cadagno

DEFF Research Database (Denmark)

Posth, Nicole Rita Elisabeth; Bristow, L. A.; Cox, R. P.

2017-01-01

carbon (POC) in the Lake Cadagno chemocline. This large fractionation between the DIC and POC was also found in culture experiments carried out with anoxygenic phototrophic bacteria isolated from the lake. In the Lake Cadagno chemocline, anoxygenic phototrophic bacteria controlled the bulk C......Anoxygenic phototrophic bacteria utilize ancient metabolic pathways to link sulfur and iron metabolism to the reduction of CO2. In meromictic Lake Cadagno, Switzerland, both purple sulfur (PSB) and green sulfur anoxygenic phototrophic bacteria (GSB) dominate the chemocline community and drive...

Virginia Solar Pathways Project: Economic Study of Utility-Administered Solar Programs: Soft Costs, Community Solar, and Tax Normalization Considerations

Energy Technology Data Exchange (ETDEWEB)

Reiter, Emerson [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lowder, Travis [National Renewable Energy Lab. (NREL), Golden, CO (United States); Mathur, Shivani [National Renewable Energy Lab. (NREL), Golden, CO (United States); Mercer, Megan [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-06-23

This report presents economic considerations for solar development in support of the Virginia Solar Pathways Project (VSPP), an effort funded by the U.S. Department of Energy (DOE) SunShot Initiative that seeks to develop a collaborative utility-administered solar strategy for the Commonwealth of Virginia. The results presented are intended to be considered alongside the results of other studies conducted under the VSPP that evaluate the impacts of solar energy on the electric distribution, transmission, and generation systems in Virginia.

Enhanced recovery pathways optimize health outcomes and resource utilization: A meta-analysis of randomized controlled trials in colorectal surgery

DEFF Research Database (Denmark)

Adamina, Michel; Kehlet, Henrik; Tomlinson, George A

2011-01-01

in costs that threatens the stability of health care systems. Enhanced recovery pathways (ERP) have been proposed as a means to reduce morbidity and improve effectiveness of care. We have reviewed the evidence supporting the implementation of ERP in clinical practice. Methods Medline, Embase...... of health care processes. Thus, while accelerating recovery and safely reducing hospital stay, ERPs optimize utilization of health care resources. ERPs can and should be routinely used in care after colorectal and other major gastrointestinal procedures....

Charting the Emergence of Corporate Procurement of Utility-Scale PV

Energy Technology Data Exchange (ETDEWEB)

Heeter, Jenny S. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Cook, Jeffrey J. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bird, Lori A. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-09-01

Through July 2017, corporate customers contracted for more than 2,300 MW of utility-scale solar. This paper examines the benefits, challenges, and outlooks for large-scale off-site solar purchasing through four pathways: PPAs, retail choice, utility partnerships (green tariffs and bilateral contracts with utilities), and by becoming a licensed wholesale seller of electricity. Each pathway differs based on where in the United States it is available, the value provided to a corporate off-taker, and the ease of implementation. The paper concludes with a discussion of future pathway comparison, noting that to deploy more corporate off-site solar, new procurement pathways are needed.

Synergistic Processing of Biphenyl and Benzoate: Carbon Flow Through the Bacterial Community in Polychlorinated-Biphenyl-Contaminated Soil

Science.gov (United States)

Leewis, Mary-Cathrine; Uhlik, Ondrej; Leigh, Mary Beth

2016-02-01

Aerobic mineralization of PCBs, which are toxic and persistent organic pollutants, involves the upper (biphenyl, BP) and lower (benzoate, BZ) degradation pathways. The activity of different members of the soil microbial community in performing one or both pathways, and their synergistic interactions during PCB biodegradation, are not well understood. This study investigates BP and BZ biodegradation and subsequent carbon flow through the microbial community in PCB-contaminated soil. DNA stable isotope probing (SIP) was used to identify the bacterial guilds involved in utilizing 13C-biphenyl (unchlorinated analogue of PCBs) and/or 13C-benzoate (product/intermediate of BP degradation and analogue of chlorobenzoates). By performing SIP with two substrates in parallel, we reveal microbes performing the upper (BP) and/or lower (BZ) degradation pathways, and heterotrophic bacteria involved indirectly in processing carbon derived from these substrates (i.e. through crossfeeding). Substrate mineralization rates and shifts in relative abundance of labeled taxa suggest that BP and BZ biotransformations were performed by microorganisms with different growth strategies: BZ-associated bacteria were fast growing, potentially copiotrophic organisms, while microbes that transform BP were oligotrophic, slower growing, organisms. Our findings provide novel insight into the functional interactions of soil bacteria active in processing biphenyl and related aromatic compounds in soil, revealing how carbon flows through a bacterial community.

(13)C metabolic flux analysis in neurons utilizing a model that accounts for hexose phosphate recycling within the pentose phosphate pathway.

Science.gov (United States)

Gebril, Hoda M; Avula, Bharathi; Wang, Yan-Hong; Khan, Ikhlas A; Jekabsons, Mika B

2016-02-01

Glycolysis, mitochondrial substrate oxidation, and the pentose phosphate pathway (PPP) are critical for neuronal bioenergetics and oxidation-reduction homeostasis, but quantitating their fluxes remains challenging, especially when processes such as hexose phosphate (i.e., glucose/fructose-6-phosphate) recycling in the PPP are considered. A hexose phosphate recycling model was developed which exploited the rates of glucose consumption, lactate production, and mitochondrial respiration to infer fluxes through the major glucose consuming pathways of adherent cerebellar granule neurons by replicating [(13)C]lactate labeling from metabolism of [1,2-(13)C2]glucose. Flux calculations were predicated on a steady-state system with reactions having known stoichiometries and carbon atom transitions. Non-oxidative PPP activity and consequent hexose phosphate recycling, as well as pyruvate production by cytoplasmic malic enzyme, were optimized by the model and found to account for 28 ± 2% and 7.7 ± 0.2% of hexose phosphate and pyruvate labeling, respectively. From the resulting fluxes, 52 ± 6% of glucose was metabolized by glycolysis, compared to 19 ± 2% by the combined oxidative/non-oxidative pentose cycle that allows for hexose phosphate recycling, and 29 ± 8% by the combined oxidative PPP/de novo nucleotide synthesis reactions. By extension, 62 ± 6% of glucose was converted to pyruvate, the metabolism of which resulted in 16 ± 1% of glucose oxidized by mitochondria and 46 ± 6% exported as lactate. The results indicate a surprisingly high proportion of glucose utilized by the pentose cycle and the reactions synthesizing nucleotides, and exported as lactate. While the in vitro conditions to which the neurons were exposed (high glucose, no lactate or other exogenous substrates) limit extrapolating these results to the in vivo state, the approach provides a means of assessing a number of metabolic fluxes within the context of hexose phosphate recycling in the PPP from a

Predicting mercury retention in utility gas cleaning systems with SCR/ESP/FGD combinations or activated carbon injection

Energy Technology Data Exchange (ETDEWEB)

Krishnakumar, Balaji; Naik, Chitralkumar V.; Niksa, Stephen [Niksa Energy Associates LLC, Belmont, CA (United States); Fujiwara, Naoki [Idemitsu Kosan Co., Ltd, Chiba (Japan). Coal and Environment Research Lab.

2013-07-01

This paper presents validations of the Hg speciation predicted by NEA's MercuRator trademark package with an American field test database for 28 full-scale utility gas cleaning systems. It emphasizes SCR/ESP/FGD combinations and activated carbon injection because these two applications present the best long- term prospects for Hg control by coal-burning utilities. Validations of the extents of Hg{sup 0} oxidation across SCRs and of Hg retention in wet FGDs gave correlation coefficients greater than 0.9 for both units. A transport-based FGD analysis correctly assessed the potential for Hg{sup 0} re-emission in one limestone wet FGD. Among the ten stations in the SCR/ESP/FGD validations, the simulations correctly identified 3 of 4 of the relatively high Hg emissions rates; all four of the sites with moderate emissions rates; and both sites with the lowest emission rates. The validations for ACI applications demonstrated that Hg removals can be accurately estimated for the full domain of coal quality, LOI, and ACI rates for both untreated and brominated carbon sorbents. The predictions for ACI depict the test-to-test variations in most cases, and accurately describe the impact of ACI configuration and sorbent type. ACI into FFs is the most effective configuration, although ACI into ESPs often removes 90% or more Hg, provided that there is sufficient residence time and Cl in the flue gas. Brominated sorbents perform better than untreated carbons, unless SO{sub 3} condensation inhibits Hg adsorption.

Form of inorganic carbon utilized for photosynthesis in Chlorella vulgaris 11h cells

International Nuclear Information System (INIS)

Miyachi, Shigetoh; Shiraiwa, Yoshihiro

1979-01-01

The rate of photosynthetic 14 CO 2 fixation in Chlorella vulgaris 11h cells in the presence of 0.55 mM NaH 14 CO 3 at pH 8.0 (20 0 C) was greatly enhanced by the addition of carbonic anhydrase (CA). However, when air containing 400 ppm 14 CO 2 was bubbled through the algal suspension, the rate of 14 CO 2 fixation immediately after the start of the bubbling was suppressed by CA. These effects of CA were observed in cells which had been grown in air containing 2% CO 2 (high-CO 2 cells) as well as those grown in ordinary air (containing 0.04% CO 2 , low-CO 2 cells). We therefore concluded that, irrespective of the CO 2 concentration given to the algal cells during growth, the active species of inorganic carbon absorbed by Chlorella cells is free CO 2 and they cannot utilize bicarbonate. The effects observed in the high-CO 2 cells were much more pronounced than those in the low-CO 2 cells. This difference was accounted for by the difference in the affinity for CO 2 in photosynthesis between the high- and low-CO 2 cells. (author)

A Commercialization Roadmap for Carbon-Negative Energy Systems

Science.gov (United States)

Sanchez, D.

2016-12-01

The Intergovernmental Panel on Climate Change (IPCC) envisages the need for large-scale deployment of net-negative CO2 emissions technologies by mid-century to meet stringent climate mitigation goals and yield a net drawdown of atmospheric carbon. Yet there are few commercial deployments of BECCS outside of niche markets, creating uncertainty about commercialization pathways and sustainability impacts at scale. This uncertainty is exacerbated by the absence of a strong policy framework, such as high carbon prices and research coordination. Here, we propose a strategy for the potential commercial deployment of BECCS. This roadmap proceeds via three steps: 1) via capture and utilization of biogenic CO2 from existing bioenergy facilities, notably ethanol fermentation, 2) via thermochemical co-conversion of biomass and fossil fuels, particularly coal, and 3) via dedicated, large-scale BECCS. Although biochemical conversion is a proven first market for BECCS, this trajectory alone is unlikely to drive commercialization of BECCS at the gigatonne scale. In contrast to biochemical conversion, thermochemical conversion of coal and biomass enables large-scale production of fuels and electricity with a wide range of carbon intensities, process efficiencies and process scales. Aside from systems integration, primarily technical barriers are involved in large-scale biomass logistics, gasification and gas cleaning. Key uncertainties around large-scale BECCS deployment are not limited to commercialization pathways; rather, they include physical constraints on biomass cultivation or CO2 storage, as well as social barriers, including public acceptance of new technologies and conceptions of renewable and fossil energy, which co-conversion systems confound. Despite sustainability risks, this commercialization strategy presents a pathway where energy suppliers, manufacturers and governments could transition from laggards to leaders in climate change mitigation efforts.

Metabolite Profile Analysis Reveals Functional Effects of 28-Day Vitamin B-6 Restriction on One-Carbon Metabolism and Tryptophan Catabolic Pathways in Healthy Men and Women123

Science.gov (United States)

da Silva, Vanessa R.; Rios-Avila, Luisa; Lamers, Yvonne; Ralat, Maria A.; Midttun, Øivind; Quinlivan, Eoin P.; Garrett, Timothy J.; Coats, Bonnie; Shankar, Meena N.; Percival, Susan S.; Chi, Yueh-Yun; Muller, Keith E.; Ueland, Per Magne; Stacpoole, Peter W.; Gregory, Jesse F.

2013-01-01

Suboptimal vitamin B-6 status, as reflected by low plasma pyridoxal 5′-phosphate (PLP) concentration, is associated with increased risk of vascular disease. PLP plays many roles, including in one-carbon metabolism for the acquisition and transfer of carbon units and in the transsulfuration pathway. PLP also serves as a coenzyme in the catabolism of tryptophan. We hypothesize that the pattern of these metabolites can provide information reflecting the functional impact of marginal vitamin B-6 deficiency. We report here the concentration of major constituents of one-carbon metabolic processes and the tryptophan catabolic pathway in plasma from 23 healthy men and women before and after a 28-d controlled dietary vitamin B-6 restriction (restriction yielded increased cystathionine (53% pre- and 76% postprandial; P restriction yielded lower kynurenic acid (22% pre- and 20% postprandial; P restriction and multilevel partial least squares-discriminant analysis supported this conclusion. Thus, plasma concentrations of creatine, cystathionine, kynurenic acid, and 3-hydroxykynurenine jointly reveal effects of vitamin B-6 restriction on the profiles of one-carbon and tryptophan metabolites and serve as biomarkers of functional effects of marginal vitamin B-6 deficiency. PMID:23966327

Facile Synthesis of Carbon-Coated Spinel Li4Ti5O12/Rutile-TiO2 Composites as an Improved Anode Material in Full Lithium-Ion Batteries with LiFePO4@N-Doped Carbon Cathode.

Science.gov (United States)

Wang, Ping; Zhang, Geng; Cheng, Jian; You, Ya; Li, Yong-Ke; Ding, Cong; Gu, Jiang-Jiang; Zheng, Xin-Sheng; Zhang, Chao-Feng; Cao, Fei-Fei

2017-02-22

The spinel Li 4 Ti 5 O 12 /rutile-TiO 2 @carbon (LTO-RTO@C) composites were fabricated via a hydrothermal method combined with calcination treatment employing glucose as carbon source. The carbon coating layer and the in situ formed rutile-TiO 2 can effectively enhance the electric conductivity and provide quick Li + diffusion pathways for Li 4 Ti 5 O 12 . When used as an anode material for lithium-ion batteries, the rate capability and cycling stability of LTO-RTO@C composites were improved in comparison with those of pure Li 4 Ti 5 O 12 or Li 4 Ti 5 O 12 /rutile-TiO 2 . Moreover, the potential of approximately 1.8 V rechargeable full lithium-ion batteries has been achieved by utilizing an LTO-RTO@C anode and a LiFePO 4 @N-doped carbon cathode.

C1 Metabolism in Corynebacterium glutamicum: an Endogenous Pathway for Oxidation of Methanol to Carbon Dioxide

Science.gov (United States)

Witthoff, Sabrina; Mühlroth, Alice

2013-01-01

Methanol is considered an interesting carbon source in “bio-based” microbial production processes. Since Corynebacterium glutamicum is an important host in industrial biotechnology, in particular for amino acid production, we performed studies of the response of this organism to methanol. The C. glutamicum wild type was able to convert 13C-labeled methanol to 13CO2. Analysis of global gene expression in the presence of methanol revealed several genes of ethanol catabolism to be upregulated, indicating that some of the corresponding enzymes are involved in methanol oxidation. Indeed, a mutant lacking the alcohol dehydrogenase gene adhA showed a 62% reduced methanol consumption rate, indicating that AdhA is mainly responsible for methanol oxidation to formaldehyde. Further studies revealed that oxidation of formaldehyde to formate is catalyzed predominantly by two enzymes, the acetaldehyde dehydrogenase Ald and the mycothiol-dependent formaldehyde dehydrogenase AdhE. The Δald ΔadhE and Δald ΔmshC deletion mutants were severely impaired in their ability to oxidize formaldehyde, but residual methanol oxidation to CO2 was still possible. The oxidation of formate to CO2 is catalyzed by the formate dehydrogenase FdhF, recently identified by us. Similar to the case with ethanol, methanol catabolism is subject to carbon catabolite repression in the presence of glucose and is dependent on the transcriptional regulator RamA, which was previously shown to be essential for expression of adhA and ald. In conclusion, we were able to show that C. glutamicum possesses an endogenous pathway for methanol oxidation to CO2 and to identify the enzymes and a transcriptional regulator involved in this pathway. PMID:24014532

Substrate specificity of glucose dehydrogenase and carbon source utilization pattern of pantoea dispersa strain P2 and its radiation induced mutants

International Nuclear Information System (INIS)

Lee, Young Keun; Murugesan, Senthilkumar

2009-01-01

Mineral phosphate solubilizing pantoea dispersa strain P2 produced 5.5 mM and 42.6 mM of gluconic acid on 24 h and 72 h incubation, respectively. Strain P2 exhibited glucose dehydrogenase (GDH) specific activity of 0.32 IU mg -1 protein. We have studied the substrate specificity of GDH as well as carbon source utilization pattern of strain P2. GDH of strain P2 did not use ribose as substrate. Utilization of lactose with specific activity of 0.65 IU mg -1 protein indicated that the enzyme belongs to GDH type B isozyme. Arabinose, galactose, ribose, sucrose and xylose did not induce the synthesis of GDH enzyme while mannose induced the synthesis of GDH with highest specific activity of 0.58 IU mg -1 protein. Through radiation mutagenesis, the substrate specificity of GDH was modified in order to utilize side range of sugars available in root exudates. Ribose, originally not a substrate for GDH of strain P2 was utilized as substrate by mutants P2-M5 with specific activity of 0.44 and 0.57 IU mg -1 protein, respectively. Specific activity of GDH on the media containing lactose and galactose was also improved to 1.2 and 0.52 IU mg -1 protein in P2-M5 and P2-M6 respectively. Based on the carbon source availability in root exudate, the mutants can be selected and utilized as efficient biofertilizer under P-deficient soil conditions

Convective Influence and Transport Pathways Controlling the Tropical Distribution of Carbon Monoxide at 100 Hpa

Science.gov (United States)

Jensen, Eric; Bergman, John; Pfister, Leonard; Ueyama, Rei; Kinnison, Doug

2014-01-01

Trajectory calculations with convective influence diagnosed from geostationary-satellite cloud measurements are used to evaluate the relative importance of different Tropical Tropopause Layer (TTL) transport pathways for establishing the distribution of carbon monoxide (CO) at 100 hPa as observed by the Microwave Limb Sounder (MLS) on board the Aura satellite. Carbon monoxide is a useful tracer for investigating TTL transport and convective influence because the CO lifetime is comparable to the time require for slow ascent through the TTL (a couple of months). Offline calculations of TTL radiative heating are used to determine the vertical motion field. The simple trajectory model does a reasonable job of reproducing the MLS CO distributions during Boreal wintertime and summertime. The broad maximum in CO concentration over the Pacific is primarily a result of the strong radiative heating (indicating upward vertical motion) associated with the abundant TTL cirrus in this region. Sensitivity tests indicate that the distinct CO maximum in the Asian monsoon anticyclone is strongly impacted by extreme convective systems with detrainment of polluted air above 360 K potential temperature. The relative importance of different CO source regions will also be discussed.

Biological conversion of carbon dioxide and hydrogen into liquid fuels and industrial chemicals.

Science.gov (United States)

Hawkins, Aaron S; McTernan, Patrick M; Lian, Hong; Kelly, Robert M; Adams, Michael W W

2013-06-01

Non-photosynthetic routes for biological fixation of carbon dioxide into valuable industrial chemical precursors and fuels are moving from concept to reality. The development of 'electrofuel'-producing microorganisms leverages techniques in synthetic biology, genetic and metabolic engineering, as well as systems-level multi-omic analysis, directed evolution, and in silico modeling. Electrofuel processes are being developed for a range of microorganisms and energy sources (e.g. hydrogen, formate, electricity) to produce a variety of target molecules (e.g. alcohols, terpenes, alkenes). This review examines the current landscape of electrofuel projects with a focus on hydrogen-utilizing organisms covering the biochemistry of hydrogenases and carbonic anhydrases, kinetic and energetic analyses of the known carbon fixation pathways, and the state of genetic systems for current and prospective electrofuel-producing microorganisms. Copyright © 2013 Elsevier Ltd. All rights reserved.

Microarray and bioinformatic analyses suggest models for carbon metabolism in the autotroph Acidithiobacillus ferrooxidans

Energy Technology Data Exchange (ETDEWEB)

C. Appia-ayme; R. Quatrini; Y. Denis; F. Denizot; S. Silver; F. Roberto; F. Veloso; J. Valdes; J. P. Cardenas; M. Esparza; O. Orellana; E. Jedlicki; V. Bonnefoy; D. Holmes

2006-09-01

Acidithiobacillus ferrooxidans is a chemolithoautotrophic bacterium that uses iron or sulfur as an energy and electron source. Bioinformatic analysis was used to identify putative genes and potential metabolic pathways involved in CO2 fixation, 2P-glycolate detoxification, carboxysome formation and glycogen utilization in At. ferrooxidans. Microarray transcript profiling was carried out to compare the relative expression of the predicted genes of these pathways when the microorganism was grown in the presence of iron versus sulfur. Several gene expression patterns were confirmed by real-time PCR. Genes for each of the above predicted pathways were found to be organized into discrete clusters. Clusters exhibited differential gene expression depending on the presence of iron or sulfur in the medium. Concordance of gene expression within each cluster, suggested that they are operons Most notably, clusters of genes predicted to be involved in CO2 fixation, carboxysome formation, 2P-glycolate detoxification and glycogen biosynthesis were up-regulated in sulfur medium, whereas genes involved in glycogen utilization were preferentially expressed in iron medium. These results can be explained in terms of models of gene regulation that suggest how A. ferrooxidans can adjust its central carbon management to respond to changing environmental conditions.

Utilization of carbon and nitrogen sources by Streptomyces ...

African Journals Online (AJOL)

We tested a number of carbon and nitrogen compounds for their effect on the production of an antibacterial antibiotic by Streptomyces kananmyceticus M27. Dextrose was found to be the most suitable carbon source, though maltose, sucrose, and soluble starch gave moderate yields. (NH4)H2PO4 and yeast extract were ...

CARBON DIOXIDE AS A FEEDSTOCK.

Energy Technology Data Exchange (ETDEWEB)

CREUTZ,C.; FUJITA,E.

2000-12-09

This report is an overview on the subject of carbon dioxide as a starting material for organic syntheses of potential commercial interest and the utilization of carbon dioxide as a substrate for fuel production. It draws extensively on literature sources, particularly on the report of a 1999 Workshop on the subject of catalysis in carbon dioxide utilization, but with emphasis on systems of most interest to us. Atmospheric carbon dioxide is an abundant (750 billion tons in atmosphere), but dilute source of carbon (only 0.036 % by volume), so technologies for utilization at the production source are crucial for both sequestration and utilization. Sequestration--such as pumping CO{sub 2} into sea or the earth--is beyond the scope of this report, except where it overlaps utilization, for example in converting CO{sub 2} to polymers. But sequestration dominates current thinking on short term solutions to global warming, as should be clear from reports from this and other workshops. The 3500 million tons estimated to be added to the atmosphere annually at present can be compared to the 110 million tons used to produce chemicals, chiefly urea (75 million tons), salicylic acid, cyclic carbonates and polycarbonates. Increased utilization of CO{sub 2} as a starting material is, however, highly desirable, because it is an inexpensive, non-toxic starting material. There are ongoing efforts to replace phosgene as a starting material. Creation of new materials and markets for them will increase this utilization, producing an increasingly positive, albeit small impact on global CO{sub 2} levels. The other uses of interest are utilization as a solvent and for fuel production and these will be discussed in turn.

Analysis of preference for carbon source utilization among three strains of aromatic compounds degrading Pseudomonas.

Science.gov (United States)

Karishma, M; Trivedi, Vikas D; Choudhary, Alpa; Mhatre, Akanksha; Kambli, Pranita; Desai, Jinal; Phale, Prashant S

2015-10-01

Soil isolates Pseudomonas putida CSV86, Pseudomonas aeruginosa PP4 and Pseudomonas sp. C5pp degrade naphthalene, phthalate isomers and carbaryl, respectively. Strain CSV86 displayed a diauxic growth pattern on phenylpropanoid compounds (veratraldehyde, ferulic acid, vanillin or vanillic acid) plus glucose with a distinct second lag-phase. The glucose concentration in the medium remained constant with higher cell respiration rates on aromatics and maximum protocatechuate 3,4-dioxygenase activity in the first log-phase, which gradually decreased in the second log-phase with concomitant depletion of the glucose. In strains PP4 and C5pp, growth profile and metabolic studies suggest that glucose is utilized in the first log-phase with the repression of utilization of aromatics (phthalate or carbaryl). All three strains utilize benzoate via the catechol 'ortho' ring-cleavage pathway. On benzoate plus glucose, strain CSV86 showed preference for benzoate over glucose in contrast to strains PP4 and C5pp. Additionally, organic acids like succinate were preferred over aromatics in strains PP4 and C5pp, whereas strain CSV86 co-metabolizes them. Preferential utilization of aromatics over glucose and co-metabolism of organic acids and aromatics are found to be unique properties of P. putida CSV86 as compared with strains PP4 and C5pp and this property of strain CSV86 can be exploited for effective bioremediation. © FEMS 2015. All rights reserved.

Fragmentation Pathways of Lithiated Hexose Monosaccharides

Science.gov (United States)

Abutokaikah, Maha T.; Frye, Joseph W.; Tschampel, John; Rabus, Jordan M.; Bythell, Benjamin J.

2018-05-01

We characterize the primary fragmentation reactions of three isomeric lithiated D-hexose sugars (glucose, galactose, and mannose) utilizing tandem mass spectrometry, regiospecific labeling, and theory. We provide evidence that these three isomers populate similar fragmentation pathways to produce the abundant cross-ring cleavage peaks (0,2A1 and 0,3A1). These pathways are highly consistent with the prior literature (Hofmeister et al. J. Am. Chem. Soc. 113, 5964-5970, 1991, Bythell et al. J. Am. Soc. Mass Spectrom. 28, 688-703, 2017, Rabus et al. Phys. Chem. Chem. Phys. 19, 25643-25652, 2017) and the present labeling data. However, the structure-specific energetics and rate-determining steps of these reactions differ as a function of precursor sugar and anomeric configuration. The lowest energy water loss pathways involve loss of the anomeric oxygen to furnish B1 ions. For glucose and galactose, the lithiated α-anomers generate ketone structures at C2 in a concerted reaction involving a 1,2-migration of the C2-H to the anomeric carbon (C1). In contrast, the β-anomers are predicted to form 1,3-anhydroglucose/galactose B1 ion structures. Initiation of the water loss reactions from each anomeric configuration requires distinct reactive conformers, resulting in different product ion structures. Inversion of the stereochemistry at C2 has marked consequences. Both lithiated mannose forms expel water to form 1,2-anhydromannose B1 ions with the newly formed epoxide group above the ring. Additionally, provided water loss is not instantaneous, the α-anomer can also isomerize to generate a ketone structure at C2 in a concerted reaction involving a 1,2-migration of the C2-H to C1. This product is indistinguishable to that from α-glucose. The energetics and interplay of these pathways are discussed. [Figure not available: see fulltext.

Inorganic Carbon Utilization of the Freshwater Red Alga Compsopogon coeruleus (Balbis Montagne (Compsopogonaceae, Rhodophyta Evaluated by in situ Measurement of Chlorophyll Fluorescence

Directory of Open Access Journals (Sweden)

Shao-Lun Liu

2004-09-01

Full Text Available To explore the inorganic carbon utilization of the freshwater red alga Compsopogon coeruleus, photosynthetic rates in response to increasing of bicarbonate concentration, the addition of alkaline HEPES buffer (pH 8.8, acid HEPES buffer (pH 4.0 and the extracellular carbonic anhydrase inhibitor (acetazolamide, AZ, respectively, were examined in situ by using a submersible pulse amplitude modulated (PAM fluorometer. Among the treatments, adding acid HEPES buffer significantly reduced photosynthetic rates of the alga, while others showed no effect. Accordingly, we concluded that C. coeruleus had less or no inorganic carbon (Ci limitation in its natural habitat. The alga might have higher affinity for bicarbonate and directly uptake bicarbonate as main Ci source without the aid of extracellular carbonic anhydrase.

Genome-Wide Survey of Pseudomonas aeruginosa PA14 Reveals a Role for the Glyoxylate Pathway and Extracellular Proteases in the Utilization of Mucin

Science.gov (United States)

Flynn, Jeffrey M.; Phan, Chi

2017-01-01

ABSTRACT Chronic airway infections by the opportunistic pathogen Pseudomonas aeruginosa are a major cause of mortality in cystic fibrosis (CF) patients. Although this bacterium has been extensively studied for its virulence determinants, biofilm growth, and immune evasion mechanisms, comparatively little is known about the nutrient sources that sustain its growth in vivo. Respiratory mucins represent a potentially abundant bioavailable nutrient source, although we have recently shown that canonical pathogens inefficiently use these host glycoproteins as a growth substrate. However, given that P. aeruginosa, particularly in its biofilm mode of growth, is thought to grow slowly in vivo, the inefficient use of mucin glycoproteins may be relevant to its persistence within the CF airways. To this end, we used whole-genome fitness analysis, combining transposon mutagenesis with high-throughput sequencing, to identify genetic determinants required for P. aeruginosa growth using intact purified mucins as a sole carbon source. Our analysis reveals a biphasic growth phenotype, during which the glyoxylate pathway and amino acid biosynthetic machinery are required for mucin utilization. Secondary analyses confirmed the simultaneous liberation and consumption of acetate during mucin degradation and revealed a central role for the extracellular proteases LasB and AprA. Together, these studies describe a molecular basis for mucin-based nutrient acquisition by P. aeruginosa and reveal a host-pathogen dynamic that may contribute to its persistence within the CF airways. PMID:28507068

Use of nuclear techniques for mutation and selection of fungi for high protein yield utilizing carbon from inexpensive agricultural waste

International Nuclear Information System (INIS)

Georgopulos, S.

1976-12-01

The report briefly describes work carried out on the following subjects: Determination of protein in fungal strains (including Fusarium and Aspergillus niger); induction and selection of mutants (Aspergillus niger) giving higher yields of biomass and/or higher protein content; ability of fungi (Candida tropicalis) to utilize water extracts of carob bean pods; growth of Fusarium monoliforme at the expense of carob sugars; the use of alternate oxidase-negative mutants (of Ustilago maydis), for better utilization of substrates for growth (electron transport pathways in reoxidation of reduced coenzymes); kinetics of batch and continuous cultivation of Fusarium moniliforme (cultivated on aqueous carob extracts)

Gene discovery for enzymes involved in limonene modification or utilization by the mountain pine beetle-associated pathogen Grosmannia clavigera.

Science.gov (United States)

Wang, Ye; Lim, Lynette; Madilao, Lina; Lah, Ljerka; Bohlmann, Joerg; Breuil, Colette

2014-08-01

To successfully colonize and eventually kill pine trees, Grosmannia clavigera (Gs cryptic species), the main fungal pathogen associated with the mountain pine beetle (Dendroctonus ponderosae), has developed multiple mechanisms to overcome host tree chemical defenses, of which terpenoids are a major component. In addition to a monoterpene efflux system mediated by a recently discovered ABC transporter, Gs has genes that are highly induced by monoterpenes and that encode enzymes that modify or utilize monoterpenes [especially (+)-limonene]. We showed that pine-inhabiting Ophiostomale fungi are tolerant to monoterpenes, but only a few, including Gs, are known to utilize monoterpenes as a carbon source. Gas chromatography-mass spectrometry (GC-MS) revealed that Gs can modify (+)-limonene through various oxygenation pathways, producing carvone, p-mentha-2,8-dienol, perillyl alcohol, and isopiperitenol. It can also degrade (+)-limonene through the C-1-oxygenated pathway, producing limonene-1,2-diol as the most abundant intermediate. Transcriptome sequencing (RNA-seq) data indicated that Gs may utilize limonene 1,2-diol through beta-oxidation and then valine and tricarboxylic acid (TCA) metabolic pathways. The data also suggested that at least two gene clusters, located in genome contigs 108 and 161, were highly induced by monoterpenes and may be involved in monoterpene degradation processes. Further, gene knockouts indicated that limonene degradation required two distinct Baeyer-Villiger monooxygenases (BVMOs), an epoxide hydrolase and an enoyl coenzyme A (enoyl-CoA) hydratase. Our work provides information on enzyme-mediated limonene utilization or modification and a more comprehensive understanding of the interaction between an economically important fungal pathogen and its host's defense chemicals.

Fructose Alters Intermediary Metabolism of Glucose in Human Adipocytes and Diverts Glucose to Serine Oxidation in the One–Carbon Cycle Energy Producing Pathway

Directory of Open Access Journals (Sweden)

Vijayalakshmi Varma

2015-06-01

Full Text Available Increased consumption of sugar and fructose as sweeteners has resulted in the utilization of fructose as an alternative metabolic fuel that may compete with glucose and alter its metabolism. To explore this, human Simpson-Golabi-Behmel Syndrome (SGBS preadipocytes were differentiated to adipocytes in the presence of 0, 1, 2.5, 5 or 10 mM of fructose added to a medium containing 5 mM of glucose representing the normal blood glucose concentration. Targeted tracer [1,2-13C2]-d-glucose fate association approach was employed to examine the influence of fructose on the intermediary metabolism of glucose. Increasing concentrations of fructose robustly increased the oxidation of [1,2-13C2]-d-glucose to 13CO2 (p < 0.000001. However, glucose-derived 13CO2 negatively correlated with 13C labeled glutamate, 13C palmitate, and M+1 labeled lactate. These are strong markers of limited tricarboxylic acid (TCA cycle, fatty acid synthesis, pentose cycle fluxes, substrate turnover and NAD+/NADP+ or ATP production from glucose via complete oxidation, indicating diminished mitochondrial energy metabolism. Contrarily, a positive correlation was observed between glucose-derived 13CO2 formed and 13C oleate and doses of fructose which indicate the elongation and desaturation of palmitate to oleate for storage. Collectively, these results suggest that fructose preferentially drives glucose through serine oxidation glycine cleavage (SOGC pathway one-carbon cycle for NAD+/NADP+ production that is utilized in fructose-induced lipogenesis and storage in adipocytes.

Utilization of the cyanobacteria Anabaena sp CH1 in biological carbon dioxide mitigation processes

Energy Technology Data Exchange (ETDEWEB)

Chiang, C.L.; Lee, C.M.; Chen, P.C. [Hungkuang University, Taichung (Taiwan)

2011-05-15

Before switching totally to alternative fuel stage, CO{sub 2} mitigation process has considered a transitional strategy for combustion of fossil fuels inevitably. In comparison to other CO{sub 2} mitigation options, such as oceanic or geologic injection, the biological photosynthetic process would present a far superior and sustainable solution under both environmental and social considerations. The utilization of the cyanobacteria Anabaena sp. CH1 in carbon dioxide mitigation processes is analyzed in our research. It was found that an original developed photobioreactor with internal light source exhibits high light utilization. Anabaena sp. CH1 demonstrates excellent CO{sub 2} tolerance even at 15% CO{sub 2} level. This enables flue gas from power plant to be directly introduced to Anabaena sp. CH1 culture. Double light intensity and increased 47% CO{sub 2} bubble retention time could enhance CO{sub 2} removal efficiencies by 79% and 67%, respectively. A maximum CO{sub 2} fixation rate of 1.01 g CO{sub 2} L{sup -1} day{sup -1} was measured experimentally.

Overview of CO2 valorization pathways. Final document

International Nuclear Information System (INIS)

Tridant Bel, Jean-Philippe; Pairin, Cecile; Darcet, Cecile; Thybaud, Nathalie; Lebain, David; David, Marc; Morin, Dominique; Bigeon, Philippe; Mansilla, Christine; Amouroux, Jacques; De Witte, Marc; Ungerer, Philippe; Jarrin, Jacques; Blancheton, Jean-Paul; Rene, Francois; Farret, Regis; Gimenez, Michel; Sassi, William; Clin, Francois; Clodic, Denis; Desnost, Carole; Gresser, Robert; Yacono, Charles

2010-06-01

Reducing the emissions of the main anthropogenic greenhouse gases, such as carbon dioxide, is one of the major challenges of this century. The growth in energy demand does not allow, at the present time, the use of fossil fuels to be avoided. As a consequence, carbon capture and storage (CCS) is a solution with great potential and is the subject of many pilot projects. In this field, France is now well positioned, despite a strongly de-carbonated electricity. As a complement to these actions, it is also possible to reuse the CO 2 molecule, considering it as a raw material, as a source of carbon. CO 2 recovery in order to produce chemical compounds is then similar to recycling and would involve an environmental benefit and an economic opportunity at the same time. In this context, the French Agency for Energy and Environment (ADEME) and the French public authorities (MEEDDM, MSR, etc.) asked ALCIMED to better understand the different pathways of CO 2 recycling and to identify the main development opportunities of such technologies in France. The results of the study also relied on the knowledge and experience of a steering committee composed of key figures from the institutional and industrial sectors. A cross-sectional analysis of the literature and telephone interviews with experts (industrial and institutional) conducted to the identification of 12 pathways of carbon dioxide recycling, that have been divided into three segments: the use of CO 2 without processing, chemical processing and biological processing. The technological, economic and environmental factors have been evaluated for each pathway, and key stakeholders and related projects have been complemented. A first analysis has been then conducted in order to compare the different pathways to each other. In addition, ALCIMED and the members of the steering committee of this study have led a first discussion on the position of France in regard to carbon dioxide recycling, putting in light industrial and

Integrated In Silico Analysis of Pathway Designs for Synthetic Photo-Electro-Autotrophy.

Directory of Open Access Journals (Sweden)

Michael Volpers

Full Text Available The strong advances in synthetic biology enable the engineering of novel functions and complex biological features in unprecedented ways, such as implementing synthetic autotrophic metabolism into heterotrophic hosts. A key challenge for the sustainable production of fuels and chemicals entails the engineering of synthetic autotrophic organisms that can effectively and efficiently fix carbon dioxide by using sustainable energy sources. This challenge involves the integration of carbon fixation and energy uptake systems. A variety of carbon fixation pathways and several types of photosystems and other energy uptake systems can be chosen and, potentially, modularly combined to design synthetic autotrophic metabolism. Prior to implementation, these designs can be evaluated by the combination of several computational pathway analysis techniques. Here we present a systematic, integrated in silico analysis of photo-electro-autotrophic pathway designs, consisting of natural and synthetic carbon fixation pathways, a proton-pumping rhodopsin photosystem for ATP regeneration and an electron uptake pathway. We integrated Flux Balance Analysis of the heterotrophic chassis Escherichia coli with kinetic pathway analysis and thermodynamic pathway analysis (Max-min Driving Force. The photo-electro-autotrophic designs are predicted to have a limited potential for anaerobic, autotrophic growth of E. coli, given the relatively low ATP regenerating capacity of the proton pumping rhodopsin photosystems and the high ATP maintenance of E. coli. If these factors can be tackled, our analysis indicates the highest growth potential for the natural reductive tricarboxylic acid cycle and the synthetic pyruvate synthase-pyruvate carboxylate -glyoxylate bicycle. Both carbon fixation cycles are very ATP efficient, while maintaining fast kinetics, which also results in relatively low estimated protein costs for these pathways. Furthermore, the synthetic bicycles are highly

Requirement of carbon dioxide for initial growth of facultative methylotroph, Acidomonas methanolica MB58.

Science.gov (United States)

Mitsui, Ryoji; Katayama, Hiroko; Tanaka, Mitsuo

2015-07-01

The facultative methylotrophic bacterium Acidomonas methanolica MB58 can utilize C1 compounds via the ribulose monophosphate pathway. A large gene cluster comprising three components related to C1 metabolism was found in the genome. From upstream, the first was an mxa cluster encoding proteins for oxidation of methanol to formaldehyde; the second was the rmp cluster encoding enzymes for formaldehyde fixation; and the third was the cbb gene cluster encoding proteins for carbon dioxide (CO2) fixation. Examination of CO2 requirements for growth of A. methanolica MB58 cells demonstrated that it did not grow on any carbon source under CO2-free conditions. Measurement of ribulose-1,5-bisphosphate carboxylase activity and RT-PCR analysis demonstrated enzymatic activity was detected in A. methanolica MB58 at growth phase, regardless of carbon sources. However, methanol dehydrogenase and 3-hexlose-6-phosphate synthase expression was regulated by methanol or formaldehyde; it were detected during growth and apparently differed from ribulose-1,5-bisphosphate carboxylase expression. These results suggested that A. methanolica MB58 may be initially dependent on autotrophic growth and that carbon assimilation was subsequently coupled with the ribulose monophosphate pathway at early- to mid-log phases during methylotrophic growth. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Pathways to deep decarbonization - 2015 report

International Nuclear Information System (INIS)

Ribera, Teresa; Colombier, Michel; Waisman, Henri; Bataille, Chris; Pierfederici, Roberta; Sachs, Jeffrey; Schmidt-Traub, Guido; Williams, Jim; Segafredo, Laura; Hamburg Coplan, Jill; Pharabod, Ivan; Oury, Christian

2015-12-01

In September 2015, the Deep Decarbonization Pathways Project published the Executive Summary of the Pathways to Deep Decarbonization: 2015 Synthesis Report. The full 2015 Synthesis Report was launched in Paris on December 3, 2015, at a technical workshop with the Mitigation Action Plans and Scenarios (MAPS) program. The Deep Decarbonization Pathways Project (DDPP) is a collaborative initiative to understand and show how individual countries can transition to a low-carbon economy and how the world can meet the internationally agreed target of limiting the increase in global mean surface temperature to less than 2 degrees Celsius (deg. C). Achieving the 2 deg. C limit will require that global net emissions of greenhouse gases (GHG) approach zero by the second half of the century. In turn, this will require a profound transformation of energy systems by mid-century through steep declines in carbon intensity in all sectors of the economy, a transition we call 'deep decarbonization'

Substrate specificity of glucose dehydrogenase and carbon source utilization pattern of pantoea dispersa strain P2 and its radiation induced mutants

Energy Technology Data Exchange (ETDEWEB)

Lee, Young Keun; Murugesan, Senthilkumar [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

2009-06-15

Mineral phosphate solubilizing pantoea dispersa strain P2 produced 5.5 mM and 42.6 mM of gluconic acid on 24 h and 72 h incubation, respectively. Strain P2 exhibited glucose dehydrogenase (GDH) specific activity of 0.32 IU mg{sup -1} protein. We have studied the substrate specificity of GDH as well as carbon source utilization pattern of strain P2. GDH of strain P2 did not use ribose as substrate. Utilization of lactose with specific activity of 0.65 IU mg{sup -1} protein indicated that the enzyme belongs to GDH type B isozyme. Arabinose, galactose, ribose, sucrose and xylose did not induce the synthesis of GDH enzyme while mannose induced the synthesis of GDH with highest specific activity of 0.58 IU mg{sup -1} protein. Through radiation mutagenesis, the substrate specificity of GDH was modified in order to utilize side range of sugars available in root exudates. Ribose, originally not a substrate for GDH of strain P2 was utilized as substrate by mutants P2-M5 with specific activity of 0.44 and 0.57 IU mg{sup -1} protein, respectively. Specific activity of GDH on the media containing lactose and galactose was also improved to 1.2 and 0.52 IU mg{sup -1} protein in P2-M5 and P2-M6 respectively. Based on the carbon source availability in root exudate, the mutants can be selected and utilized as efficient biofertilizer under P-deficient soil conditions.

Primary Metabolic Pathways and Metabolic Flux Analysis

DEFF Research Database (Denmark)

Villadsen, John

2015-01-01

his chapter introduces the metabolic flux analysis (MFA) or stoichiometry-based MFA, and describes the quantitative basis for MFA. It discusses the catabolic pathways in which free energy is produced to drive the cell-building anabolic pathways. An overview of these primary pathways provides...... the reader who is primarily trained in the engineering sciences with atleast a preliminary introduction to biochemistry and also shows how carbon is drained off the catabolic pathways to provide precursors for cell mass building and sometimes for important industrial products. The primary pathways...... to be examined in the following are: glycolysis, primarily by the EMP pathway, but other glycolytic pathways is also mentioned; fermentative pathways in which the redox generated in the glycolytic reactions are consumed; reactions in the tricarboxylic acid (TCA) cycle, which produce biomass precursors and redox...

Evaluating glymphatic pathway function utilizing clinically relevant intrathecal infusion of CSF tracer.

Science.gov (United States)

Yang, Lijun; Kress, Benjamin T; Weber, Harris J; Thiyagarajan, Meenakshisundaram; Wang, Baozhi; Deane, Rashid; Benveniste, Helene; Iliff, Jeffrey J; Nedergaard, Maiken

2013-05-01

Neurodegenerative diseases such as Alzheimer's are associated with the aggregation of endogenous peptides and proteins that contribute to neuronal dysfunction and loss. The glymphatic system, a brain-wide perivascular pathway along which cerebrospinal fluid (CSF) and interstitial fluid (ISF) rapidly exchange, has recently been identified as a key contributor to the clearance of interstitial solutes from the brain, including amyloid β. These findings suggest that measuring changes in glymphatic pathway function may be an important prognostic for evaluating neurodegenerative disease susceptibility or progression. However, no clinically acceptable approach to evaluate glymphatic pathway function in humans has yet been developed. Time-sequenced ex vivo fluorescence imaging of coronal rat and mouse brain slices was performed at 30-180 min following intrathecal infusion of CSF tracer (Texas Red- dextran-3, MW 3 kD; FITC- dextran-500, MW 500 kD) into the cisterna magna or lumbar spine. Tracer influx into different brain regions (cortex, white matter, subcortical structures, and hippocampus) in rat was quantified to map the movement of CSF tracer following infusion along both routes, and to determine whether glymphatic pathway function could be evaluated after lumbar intrathecal infusion. Following lumbar intrathecal infusions, small molecular weight TR-d3 entered the brain along perivascular pathways and exchanged broadly with the brain ISF, consistent with the initial characterization of the glymphatic pathway in mice. Large molecular weight FITC-d500 remained confined to the perivascular spaces. Lumbar intrathecal infusions exhibited a reduced and delayed peak parenchymal fluorescence intensity compared to intracisternal infusions. Lumbar intrathecal contrast delivery is a clinically useful approach that could be used in conjunction with dynamic contrast enhanced MRI nuclear imaging to assess glymphatic pathway function in humans.

Toxicity and efficacy of carbon nanotubes and graphene: the utility of carbon-based nanoparticles in nanomedicine.

Science.gov (United States)

Zhang, Yongbin; Petibone, Dayton; Xu, Yang; Mahmood, Meena; Karmakar, Alokita; Casciano, Dan; Ali, Syed; Biris, Alexandru S

2014-05-01

Carbon-based nanomaterials have attracted great interest in biomedical applications such as advanced imaging, tissue regeneration, and drug or gene delivery. The toxicity of the carbon nanotubes and graphene remains a debated issue although many toxicological studies have been reported in the scientific community. In this review, we summarize the biological effects of carbon nanotubes and graphene in terms of in vitro and in vivo toxicity, genotoxicity and toxicokinetics. The dose, shape, surface chemistry, exposure route and purity play important roles in the metabolism of carbon-based nanomaterials resulting in differential toxicity. Careful examination of the physico-chemical properties of carbon-based nanomaterials is considered a basic approach to correlate the toxicological response with the unique properties of the carbon nanomaterials. The reactive oxygen species-mediated toxic mechanism of carbon nanotubes has been extensively discussed and strategies, such as surface modification, have been proposed to reduce the toxicity of these materials. Carbon-based nanomaterials used in photothermal therapy, drug delivery and tissue regeneration are also discussed in this review. The toxicokinetics, toxicity and efficacy of carbon-based nanotubes and graphene still need to be investigated further to pave a way for biomedical applications and a better understanding of their potential applications to humans.

Synthesis and utilization of carbon nanotubes for fabrication of electrochemical biosensors

International Nuclear Information System (INIS)

Lawal, Abdulazeez T.

2016-01-01

Graphical abstract: Carbon nanotubes. - Highlights: • This review discusses synthesis and applications of carbon nanotubes sensors. • The review summarizes contributions of carbon nanotube to electrochemical biosensor. • Good electrical conductivity makes carbon nanotubes a good material for biosensors. • Carbon nanotubes promotes electron transfer that aids biosensing of biomolecules. - Abstract: This review summarizes the most recent contributions in the fabrication of carbon nanotubes-based electrochemical biosensors in recent years. It discusses the synthesis and application of carbon nanotubes to the assembly of carbon nanotube-based electrochemical sensors, its analytical performance and future expectations. An increasing number of reviews and publications involving carbon nanotubes sensors have been reported ever since the first design of carbon nanotube electrochemical biosensors. The large surface area and good electrical conductivity of carbon nanotubes allow them to act as “electron wire” between the redox center of an enzyme or protein and an electrode's surface, which make them very excellent material for the design of electrochemical biosensors. Carbon nanotubes promote the different rapid electron transfers that facilitate accurate and selective detection of cytochrome-c, β-nicotinamide adenine dinucleotide, hemoglobin and biomolecules, such as glucose, cholesterol, ascorbic acid, uric acid, dopamine pesticides, metals ions and hydrogen peroxide.

Synthesis and utilization of carbon nanotubes for fabrication of electrochemical biosensors

Energy Technology Data Exchange (ETDEWEB)

Lawal, Abdulazeez T., E-mail: abdul.lawal@yahoo.com

2016-01-15

Graphical abstract: Carbon nanotubes. - Highlights: • This review discusses synthesis and applications of carbon nanotubes sensors. • The review summarizes contributions of carbon nanotube to electrochemical biosensor. • Good electrical conductivity makes carbon nanotubes a good material for biosensors. • Carbon nanotubes promotes electron transfer that aids biosensing of biomolecules. - Abstract: This review summarizes the most recent contributions in the fabrication of carbon nanotubes-based electrochemical biosensors in recent years. It discusses the synthesis and application of carbon nanotubes to the assembly of carbon nanotube-based electrochemical sensors, its analytical performance and future expectations. An increasing number of reviews and publications involving carbon nanotubes sensors have been reported ever since the first design of carbon nanotube electrochemical biosensors. The large surface area and good electrical conductivity of carbon nanotubes allow them to act as “electron wire” between the redox center of an enzyme or protein and an electrode's surface, which make them very excellent material for the design of electrochemical biosensors. Carbon nanotubes promote the different rapid electron transfers that facilitate accurate and selective detection of cytochrome-c, β-nicotinamide adenine dinucleotide, hemoglobin and biomolecules, such as glucose, cholesterol, ascorbic acid, uric acid, dopamine pesticides, metals ions and hydrogen peroxide.

Comparison of plants with C3 and C4 carbon fixation pathways for remediation of polycyclic aromatic hydrocarbon contaminated soils

OpenAIRE

Sivaram, Anithadevi Kenday; Logeshwaran, Panneerselvan; Subashchandrabose, Suresh R.; Lockington, Robin; Naidu, Ravi; Megharaj, Mallavarapu

2018-01-01

The phytoremediation technique has been demonstrated to be a viable option for the remediation of polycyclic aromatic hydrocarbons (PAHs) contaminated sites. This study evaluated the potential applicability of plants with C3 and C4 carbon fixation pathways for the phytoremediation of recalcitrant high molecular weight (HMW) PAHs contaminated soil. A 60 and 120-day greenhouse study was conducted which showed higher degradation of HMW PAHs in soil grown with C4 plants when compared to C3 plants...

A collaborative project on the effects of coal quality on NO{sub x} emissions and carbon burnout in pulverised coal-fired utility boilers

Energy Technology Data Exchange (ETDEWEB)

Tilley, H.A.; O`Connor, M.; Stephenson, P.L.; Whitehouse, M.; Richards, D.G.; Hesselmann, G.; MacPhail, J.; Lockwood, F.C.; Williamson, J.; Williams, A.; Pourkashanian, M. [ETSU, Harwell (United Kingdom)

1998-12-01

This paper describes a UK Department of Trade and Industry-supported collaborative project entitled `The Effects of Coal Quality on Emission of Oxides of Nitrogen (NO{sub x}) and Carbon Burnout in Pulverised Coal-fired Utility Boilers`. The project involved extensive collaboration between the UK power generators, boiler and burner manufacturers and research groups in both industry and academia, together with several of the world`s leading computational fluid dynamics (CFD) `software houses`. The prime objectives of the project were to assess the relationship between NO{sub x} emissions and carbon burnout and to develop and validate predictive tools for assessing coals. Experimental work was carried out on various laboratory-scale apparatus and on single burner test facilities ranging from 160 kW{sub th} to 40 MW{sub th} in size and measurements were obtained from full-scale 500 MW{sub e} utility boiler trials. This data and basic coal data were then used to develop mathematical models to predict full-scale boiler performance with respect to NO{sub x} emissions and carbon-in-ash. Results showed good correlations for NO{sub x} and carbon burnout when comparing data from full-scale and large-scale rig trials. Laboratory-scale tests were found to be useful but the influence of burner aerodynamics was more difficult to quantify. Modelling showed that predicted NO{sub x} emissions were encouragingly close to measured emissions but predicting carbon burnout was less successful. 24 refs., 4 figs., 6 tabs.

Vertically aligned carbon nanotubes/carbon fiber paper composite to support Pt nanoparticles for direct methanol fuel cell application

Science.gov (United States)

Zhang, Jing; Yi, Xi-bin; Liu, Shuo; Fan, Hui-Li; Ju, Wei; Wang, Qi-Chun; Ma, Jie

2017-03-01

Vertically aligned carbon nanotubes (VACNTs) grown on carbon fiber paper (CFP) by plasma enhanced chemical vapor deposition is introduced as a catalyst support material for direct methanol fuel cells (DMFCs). Well dispersed Pt nanoparticles on VACNTs surface are prepared by impregnation-reduction method. The VACNTs on CFP possess well-maintained alignment, large surface area and good electrical conductivity, which leading to the formation of Pt particles with a smaller size and enhance the Pt utilization rate. The structure and nature of resulting Pt/VACNTs/CFP catalysts for methanol oxidation are investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD) and scanning electron microscope (SEM). With the aid of VACNTs, well-dispersed Pt catalysts enable the reversibly rapid redox kinetic since electron transport efficiently passes through a one-dimensional pathway, which leads to enhance the catalytic activity and Pt utilization rate. Compared with the Pt/XC-72/CFP electrode, the electrochemical measurements results display that the Pt/VACNTs/CFP catalyst shows much higher electrocatalytic activity and better stability for methanol oxidation. In addition, the oxidation current from 200 to 1200 s decayed more slowly for the Pt/VACNTs/CFP than that of the Pt/XC-72/CFP catalysts, indicating less accumulation of adsorbed CO species. All those results imply that the Pt/VACNTs/CFP has a great potential for applications in DMFCs.

Towards an understanding of the molecular regulation of carbon allocation in diatoms: the interaction of energy and carbon allocation.

Science.gov (United States)

Wagner, Heiko; Jakob, Torsten; Fanesi, Andrea; Wilhelm, Christian

2017-09-05

In microalgae, the photosynthesis-driven CO 2 assimilation delivers cell building blocks that are used in different biosynthetic pathways. Little is known about how the cell regulates the subsequent carbon allocation to, for example, cell growth or for storage. However, knowledge about these regulatory mechanisms is of high biotechnological and ecological importance. In diatoms, the situation becomes even more complex because, as a consequence of their secondary endosymbiotic origin, the compartmentation of the pathways for the primary metabolic routes is different from green algae. Therefore, the mechanisms to manipulate the carbon allocation pattern cannot be adopted from the green lineage. This review describes the general pathways of cellular energy distribution from light absorption towards the final allocation of carbon into macromolecules and summarizes the current knowledge of diatom-specific allocation patterns. We further describe the (limited) knowledge of regulatory mechanisms of carbon partitioning between lipids, carbohydrates and proteins in diatoms. We present solutions to overcome the problems that hinder the identification of regulatory elements of carbon metabolism.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'. © 2017 The Author(s).

Utilization of carbon 13-labelled stable isotopes for studying drug toxicity on cellular metabolism

International Nuclear Information System (INIS)

Herve, M.; Wietzerbin, J.; Tran-Dinh, S.

1994-01-01

A new approach for studying the effects of two drugs, amphotericine B (AMB), an anti-fungal antibiotic, and 2-deoxy-D-glucose (DG), on the glucose metabolism in brewer yeast cells (Saccharomyces cerevisiae), is presented; AMB interacts with the membrane sterols, inducing formation of pores through which ions and small molecules can pass. DG may enter in the cytosol, where it is phosphoryled by hexokinase into deoxy-D-glucose 6-phosphate (DG6P) which disappears very slowly. DG slows down the glycolysis process and induces the formation of new substances. This paper shows the advantages of utilizing carbon 13-labelled substrates combined to the NMR-13C and NMR-1H techniques. 6 figs., 5 refs

The effects of coal quality on NO{sub x} emissions and carbon burnout in pulverised coal-fired utility boilers

Energy Technology Data Exchange (ETDEWEB)

O`Connor, M. [National Power plc, Swindon (United Kingdom)

1999-04-01

A comprehensive study is reported on the impact of coal quality on nitrogen oxides emissions and carbon burnout in utility boilers, with the aim of assessing their relationship and developing predictive tools for assessing coals. Experimental work was carried out on various laboratory-scale apparatus and on single burner test facilities ranging from 160 kW{sub th} to 40 MW{sub th} in size and measurements were obtained from full-scale 500 MW{sub e} utility boiler trials. This data and basic coal data were then used to develop mathematical models to predict full-scale boiler performance with respect to NO{sub x} emissions and carbon burnout. Power station trials demonstrated that coal quality effects nitrogen oxides and burnout. The variability in boiler conditions also impacted on these factors. Lower nitrogen and higher volatile coals generally produced less NO{sub x}. Volatile content was the most important generic coal property for predicting burnout. Modelling rig tests, using data from advanced laboratory-scale tests, were found to be just as successful as using rig tests for predicting NO{sub x} performance of different coals. Laboratory-scale tests were found to be successful in providing accurate predictions of burnout for the coals studied. Mathematical models, however, were found to be less successful in this area and further work to develop this is required. A major achievement was CFD solutions of full-scale utility boiler furnaces in a single mesh. 32 refs., 15 figs., 33 tabs., 2 apps.

METABOLIC ENGINEERING TO DEVELOP A PATHWAY FOR THE SELECTIVE CLEAVAGE OF CARBON-NITROGEN BONDS

Energy Technology Data Exchange (ETDEWEB)

John J. Kilbane II

2004-10-01

The objective of the project is to develop biochemical pathways for the selective cleavage of C-N bonds in molecules found in petroleum. The initial phase of the project was focused on the isolation or development of an enzyme capable of cleaving the C-N bond in aromatic amides, specifically 2-aminobiphenyl. The objective of the second phase of the research will be to construct a biochemical pathway for the selective removal of nitrogen from carbazole by combining the carA genes from Sphingomonas sp. GTIN11 with the gene(s) encoding an appropriate deaminase. The objective of the final phase of the project will be to develop derivative C-N bond cleaving enzymes that have broader substrate ranges and to demonstrate the use of such strains to selectively remove nitrogen from petroleum. During the first year of the project (October, 2002-September, 2003) enrichment culture experiments resulted in the isolation of microbial cultures that utilize aromatic amides as sole nitrogen sources, several amidase genes were cloned and were included in directed evolution experiments to obtain derivatives that can cleave C-N bonds in aromatic amides, and the carA genes from Sphingomonas sp. GTIN11, and Pseudomonas resinovorans CA10 were cloned in vectors capable of replicating in Escherichia coli. During the second year of the project (October, 2003-September, 2004) enrichment culture experiments succeeded in isolating a mixed bacterial culture that can utilize 2-aminobiphenyl as a sole nitrogen source, directed evolution experiments were focused on the aniline dioxygenase enzyme that is capable of deaminating aniline, and expression vectors were constructed to enable the expression of genes encoding C-N bond cleaving enzymes in Rhodococcus hosts. The construction of a new metabolic pathway to selectively remove nitrogen from carbazole and other molecules typically found in petroleum should lead to the development of a process to improve oil refinery efficiency by reducing the

BIOGENIC VS. ABIOGENIC ISOTOPE SIGNATURES OF REDUCED CARBON COMPOUNDS: A LESSON FROM HYDROTHERMAL SYNTHESIS EXPERIMENTS

International Nuclear Information System (INIS)

Horita, J.

2001-01-01

With growing interest in and demonstrated cases of inorganic hydrothermal synthesis of reduced or organic carbon compounds from CO and CO(sub 2), it becomes crucial to establish geochemical criteria to distinguish reduced/organic carbon compounds of abiogenic origin from those of biogenic origin with overwhelming abundances on the surface and in subsurface of the Earth. Chemical and isotopic compositions, particularly(sup 13)C/(sup 12)C ratios, of reduced/organic carbon compounds have been widely utilized for deducing the origins and formation pathways of these compounds. An example is isotopic and C(sub 1)/(C(sub 2)+C(sub 3)) ratios of natural gases, which have been used to distinguish bacterial, thermogenic, and possible abiogenic origins. Another example is that ancient graphitic carbon with(delta)(sup 13)C values c-25per thousand has been considered of biogenic origin. Although these criteria could be largely valid, growing data including those from our hydrothermal experiments suggest that a great caution must be exercised

Toxicological Investigation of Acute Carbon Monoxide Poisoning in Four Occupants of a Fuming Sport Utility Vehicle

Directory of Open Access Journals (Sweden)

Martin Nnoli

2014-11-01

Full Text Available Background: This toxicological investigation involves a report on the death of four occupants of a sport utility vehicle on one of the major busy Federal roads of Nigeria where they were held for up to three hours in a traffic jam while the car was steaming. Methods: Autopsy was executed using the standard procedure and toxicological analysis was done using simple spectrophotometric method to establish the level of carboxyhaemoglobin (HbCO in peripheral blood in the four occupants. Results: The autopsy report indicated generalized cyanosis, sub-conjuctival hemorrhages, marked laryngo-trachea edema with severe hyperemia with frothy fluid discharges characteristic of carbon monoxide poisoning. Toxicological report of the level of HbCO in part per million (ppm in the peripheral blood of the four occupants was A= 650 ppm; B= 500 ppm; C= 480 ppm, and D= 495 ppm against the maximum permissible level of 50 ppm. Conclusion: The sudden death of the four occupants was due to excessive inhalation of the carbon monoxide gas from the exhaust fumes leaking into the cabin of the car. The poor road network, numerous potholes, and traffic jam in most of roads in Nigeria could have exacerbated a leaky exhaust of the smoky second hand SUV car leading to the acute carbon monoxide poisoning.

Utilization of HTGR on active carbon recycling energy system

Energy Technology Data Exchange (ETDEWEB)

Kato, Yukitaka, E-mail: yukitaka@nr.titech.ac.jp

2014-05-01

A new energy transformation concept based on carbon recycling, called as active carbon recycling energy system, ACRES, was proposed for a zero carbon dioxide emission process. The ACRES is driven availably by carbon dioxide free primary energy. High temperature gas cooled reactor (HTGR) is a candidate of the energy sources for ACRES. A smart ironmaking system with ACRES (iACRES) is one of application examples. The contribution of HTGR on iACRES was discussed thermodynamically in this study. A carbon material is re-used cyclically as energy carrier media in ACRES. Carbon monoxide (CO) had higher energy densities than hydrogen and was compatible with conventional process. Thus, CO was suitable recycling media for ACRES. Efficient regeneration of CO was a key technology for ACRES. A combined system of hydrogen production by water electrolysis and CO{sub 2} hydrogen reduction was candidate. CO{sub 2} direct electrolysis was also one of the candidates. HTGR was appropriate heat source for both water and CO{sub 2} electrolysises, and CO{sub 2} hydrogen reduction. Thermodynamic energy balances were calculated for both systems with HTGR for an ironmaking system. The direct system showed relatively advantage to the combined system in the stand point of enthalpy efficiency and simplicity of the process. One or two plants of HTGR are corresponding with ACRES system for one unit of conventional blast furnace. The proposed ACRES system with HTGR was expected to form the basis of a new energy industrial process that had low CO{sub 2} emission.

Stable carbon isotope ratios: implications for the source of sediment carbon and for phytoplankton carbon assimilation in Lake Memphremagog, Quebec

International Nuclear Information System (INIS)

LaZerte, B.D.

1983-01-01

The stable carbon isotope (SCI) ratio of the sediment of Lake Memphremagog, Quebec is compared with that ot terrestrial sources and the phytoplankton to determine the relative proportion of allochthonous carbon incorporated into the sediments. Approximately 40-50% of the organic carbon in the main basins' pelagic sediment was terrestrial in origin, whereas up to 100% was terrestrial in littoral areas. The SCI method of determining the organic carbon source of sediments appears more reliable than the C/N method. A comparison of the SCI fractionation of the phytoplankton with laboratory cultures under different degrees of carbon limitation indicates that the phytoplankton of Lake Memphremagog are not carbon limited and fix carbon primarily by the C 3 pathway

Simultaneous genome-wide inference of physical, genetic, regulatory, and functional pathway components.

Directory of Open Access Journals (Sweden)

Christopher Y Park

2010-11-01

Full Text Available Biomolecular pathways are built from diverse types of pairwise interactions, ranging from physical protein-protein interactions and modifications to indirect regulatory relationships. One goal of systems biology is to bridge three aspects of this complexity: the growing body of high-throughput data assaying these interactions; the specific interactions in which individual genes participate; and the genome-wide patterns of interactions in a system of interest. Here, we describe methodology for simultaneously predicting specific types of biomolecular interactions using high-throughput genomic data. This results in a comprehensive compendium of whole-genome networks for yeast, derived from ∼3,500 experimental conditions and describing 30 interaction types, which range from general (e.g. physical or regulatory to specific (e.g. phosphorylation or transcriptional regulation. We used these networks to investigate molecular pathways in carbon metabolism and cellular transport, proposing a novel connection between glycogen breakdown and glucose utilization supported by recent publications. Additionally, 14 specific predicted interactions in DNA topological change and protein biosynthesis were experimentally validated. We analyzed the systems-level network features within all interactomes, verifying the presence of small-world properties and enrichment for recurring network motifs. This compendium of physical, synthetic, regulatory, and functional interaction networks has been made publicly available through an interactive web interface for investigators to utilize in future research at http://function.princeton.edu/bioweaver/.

Negative Emissions: Where Will the Carbon Come From?

Science.gov (United States)

Aines, R. D.; McCoy, S. T.

2017-12-01

The need for energy technologies that remove carbon dioxide from the air grows with each year of delay in acting to address climate change. The most commonly mentioned approach for achieving that, bioenergy with carbon capture and storage (BECCS), today is largely a modeler's concept, not a technology. Thus, in the near term how can we confidently discuss the scale of biomass for energy with a net reduction in CO2 concentrations in the absence of examples? As a first step toward achieving that research objective, this talk frames the likely ways in which net reductions in CO2 concentrations can be achieved from a lifecycle perspective, and the pathways through which biomass can be converted to fuels and materials while removing CO2 from the atmosphere. We will address questions such as: What pathways exist for converting biomass into transportation fuels, electricity, and materials? How can we capture and manage the carbon dioxide emissions from these kinds of activities? And, what are the tradeoffs between pathways? We have conducted preliminary analyses of some of the common biofuel production pathways, such as ethanol from corn with and without carbon capture. These pathways are still uniformly carbon positive, that is to say, they do not achieve the goal of reducing atmospheric CO2, even if they result in lower emissions than do petroleum-based fuels. More advanced pathways appear to have the capacity for minor atmospheric reductions, including those for drop-in replacement transportation fuels and some long-lived materials. Targets and options for improving these technologies to the point that they can, in fact, be carbon negative will be discussed, including pre-processing of the biomass near the production site to reduce transportation emissions, finding ways to manage small CO2 sources associated with processing, and uses of biochar. We will end with a summary of near-term RD&D needs to advance carbon-negative pathways and the associated technologies. This

Carbon footprint of forest and tree utilization technologies in life cycle approach

Science.gov (United States)

Polgár, András; Pécsinger, Judit

2017-04-01

In our research project a suitable method has been developed related the technological aspect of the environmental assessment of land use changes caused by climate change. We have prepared an eco-balance (environmental inventory) to the environmental effects classification in life-cycle approach in connection with the typical agricultural / forest and tree utilization technologies. The use of balances and environmental classification makes possible to compare land-use technologies and their environmental effects per common functional unit. In order to test our environmental analysis model, we carried out surveys in sample of forest stands. We set up an eco-balance of the working systems of intermediate cutting and final harvest in the stands of beech, oak, spruce, acacia, poplar and short rotation energy plantations (willow, poplar). We set up the life-cycle plan of the surveyed working systems by using the GaBi 6.0 Professional software and carried out midpoint and endpoint impact assessment. Out of the results, we applied the values of CML 2001 - Global Warming Potential (GWP 100 years) [kg CO2-Equiv.] and Eco-Indicator 99 - Human health, Climate Change [DALY]. On the basis of the values we set up a ranking of technology. By this, we received the environmental impact classification of the technologies based on carbon footprint. The working systems had the greatest impact on global warming (GWP 100 years) throughout their whole life cycle. This is explained by the amount of carbon dioxide releasing to the atmosphere resulting from the fuel of the technologies. Abiotic depletion (ADP foss) and marine aquatic ecotoxicity (MAETP) emerged also as significant impact categories. These impact categories can be explained by the share of input of fuel and lube. On the basis of the most significant environmental impact category (carbon footprint), we perform the relative life cycle contribution and ranking of each technologies. The technological life cycle stages examined

A Synthetic Alternative to Canonical One-Carbon Metabolism.

Science.gov (United States)

Bouzon, Madeleine; Perret, Alain; Loreau, Olivier; Delmas, Valérie; Perchat, Nadia; Weissenbach, Jean; Taran, Frédéric; Marlière, Philippe

2017-08-18

One-carbon metabolism is an ubiquitous metabolic pathway that encompasses the reactions transferring formyl-, hydroxymethyl- and methyl-groups bound to tetrahydrofolate for the synthesis of purine nucleotides, thymidylate, methionine and dehydropantoate, the precursor of coenzyme A. An alternative cyclic pathway was designed that substitutes 4-hydroxy-2-oxobutanoic acid (HOB), a compound absent from known metabolism, for the amino acids serine and glycine as one-carbon donors. It involves two novel reactions, the transamination of l-homoserine and the transfer of a one-carbon unit from HOB to tetrahydrofolate releasing pyruvate as coproduct. Since canonical reactions regenerate l-homoserine from pyruvate by carboxylation and subsequent reduction, every one-carbon moiety made available for anabolic reactions originates from CO 2 . The HOB-dependent pathway was established in an Escherichia coli auxotroph selected for prototrophy using long-term cultivation protocols. Genetic, metabolic and biochemical evidence support the emergence of a functional HOB-dependent one-carbon pathway achieved with the recruitment of the two enzymes l-homoserine transaminase and HOB-hydroxymethyltransferase and of HOB as an essential metabolic intermediate. Escherichia coli biochemical reprogramming was achieved by minimally altering canonical metabolism and leveraging on natural selection mechanisms, thereby launching the resulting strain on an evolutionary trajectory diverging from all known extant species.

Pathways Utilized for Antenatal Health Seeking Among Women in ...

African Journals Online (AJOL)

Background: Ghana's maternal mortality ratio has been declining over the last two decades but at a rather slow pace. Poor access to effective maternity care is identified as one of the key challenges of maternity care. The current study mapped out the pathways to pregnancy care seeking among urban-dwelling adult women ...

Compound-Specific Isotopic Analysis of Meteoritic Amino Acids as a Tool for Evaluating Potential Formation Pathways

Science.gov (United States)

Elsila, Jamie E.; Burton, Aaron S.; Callahan, Michael C.; Charnley, Steven B.; Glavin, Daniel P.; Dworkin, Jason P.

2012-01-01

Measurements of stable hydrogen, carbon, and nitrogen isotopic ratios (delta D, delta C-13, delta N-15) of organic compounds can reveal information about their origin and formation pathways. Several formation mechanisms and environments have been postulated for the amino acids detected in carbonaceous chondrites. As each proposed mechanism utilizes different precursor molecules, the isotopic signatures of the resulting amino acids may point towards the most likely of these proposed pathways. The technique of gas chromatography coupled with mass spectrometry and isotope ratio mass spectrometry provides compound-specific structural and isotopic information from a single splitless injection, enhancing the amount of information gained from small amounts of precious samples such as carbonaceous chondrites. We have applied this technique to measure the compound-specific C, N, and H isotopic ratios of amino acids from seven CM and CR carbonaceous chondrites. We are using these measurements to evaluate predictions of expected isotopic enrichments from potential formation pathways and environments, leading to a better understanding of the origin of these compounds.

A new infusion pathway monitoring system utilizing electrostatic induced potential.

Science.gov (United States)

Maki, Hiromichi; Yonezawa, Yoshiharu; Ogawa, Hidekuni; Ninomiya, Ishio; Sada, Kouji; Hamada, Shingo; Hahn, Alien W; Caldwell, W Morton

2006-01-01

We have developed a new infusion pathway monitoring system employing linear integrated circuits and a low-power 8-bit single chip microcomputer. The system is available for hospital and home use and it constantly monitors the intactness of the pathway. The sensor is an electro-conductive polymer electrode wrapped around the infusion polyvinyl chloride infusion tube. This records an AC (alternating current) voltage induced on the patient's body by electrostatic coupling from the normal 100 volt, 60 Hz AC power line wiring field in the patient's room. If the injection needle or infusion tube becomes detached, then the system detects changes in the induced AC voltage and alerts the nursing station, via the nurse call system or PHS (personal handy phone System).

Low Carbon Development Pathways in Indian Agriculture

Directory of Open Access Journals (Sweden)

Wang Sonam Wangyel

2017-01-01

Full Text Available Indian agriculture sector is a significant emitter of Green House Gas (GHG, which is projected to increase by 47% between 2011 and 2020. In response to this, India has committed itself to voluntarily reduce its emissions intensity (emissions per unit GDP between 20 to 25 percent below 2005 levels by 2020. This would require rapid and significant scaling up of mitigation efforts including the agriculture sector, which remains a challenge, as mitigation is not a priority in Indian agriculture. The study found out that in-spite of numerous mitigation technologies that are readily available for takeoff, the scale of adoption and deployment is far from sufficient to meet the emission targets set by the Government of India, mainly due to lack of financial incentives, capacity building of farmers, and an enabling policy at different levels. This study identified a suite of feasible interventions for promoting low carbon agriculture such as: low tillage systems as it has negative costs due to savings on tillage and fuel; introduction of superior livestock breeds to reduce numbers (especially unproductive cattle and increase yield; use of livestock wastes to produce energy for cooking and heating through bio-gas technology can not only reduce methane emission but also save electricity costs for the households and; introduction of carbon credits and exploration of domestic carbon markets. An enabling policy environment must be created for these interventions to take off.

Crystallization Pathways in Biomineralization

Science.gov (United States)

Weiner, Steve; Addadi, Lia

2011-08-01

A crystallization pathway describes the movement of ions from their source to the final product. Cells are intimately involved in biological crystallization pathways. In many pathways the cells utilize a unique strategy: They temporarily concentrate ions in intracellular membrane-bound vesicles in the form of a highly disordered solid phase. This phase is then transported to the final mineralization site, where it is destabilized and crystallizes. We present four case studies, each of which demonstrates specific aspects of biological crystallization pathways: seawater uptake by foraminifera, calcite spicule formation by sea urchin larvae, goethite formation in the teeth of limpets, and guanine crystal formation in fish skin and spider cuticles. Three representative crystallization pathways are described, and aspects of the different stages of crystallization are discussed. An in-depth understanding of these complex processes can lead to new ideas for synthetic crystallization processes of interest to materials science.

SU-E-J-37: Feasibility of Utilizing Carbon Fiducials to Increase Localization Accuracy of Lumpectomy Cavity for Partial Breast Irradiation

International Nuclear Information System (INIS)

Zhang, Y; Hieken, T; Mutter, R; Park, S; Yan, E; Brinkmann, D; Pafundi, D

2015-01-01

Purpose To investigate the feasibility of utilizing carbon fiducials to increase localization accuracy of lumpectomy cavity for partial breast irradiation (PBI). Methods Carbon fiducials were placed intraoperatively in the lumpectomy cavity following resection of breast cancer in 11 patients. The patients were scheduled to receive whole breast irradiation (WBI) with a boost or 3D-conformal PBI. WBI patients were initially setup to skin tattoos using lasers, followed by orthogonal kV on-board-imaging (OBI) matching to bone per clinical practice. Cone beam CT (CBCT) was acquired weekly for offline review. For the boost component of WBI and PBI, patients were setup with lasers, followed by OBI matching to fiducials, with final alignment by CBCT matching to fiducials. Using carbon fiducials as a surrogate for the lumpectomy cavity and CBCT matching to fiducials as the gold standard, setup uncertainties to lasers, OBI bone, OBI fiducials, and CBCT breast were compared. Results Minimal imaging artifacts were introduced by fiducials on the planning CT and CBCT. The fiducials were sufficiently visible on OBI for online localization. The mean magnitude and standard deviation of setup errors were 8.4mm ± 5.3 mm (n=84), 7.3mm ± 3.7mm (n=87), 2.2mm ± 1.6mm (n=40) and 4.8mm ± 2.6mm (n=87), for lasers, OBI bone, OBI fiducials and CBCT breast tissue, respectively. Significant migration occurred in one of 39 implanted fiducials in a patient with a large postoperative seroma. Conclusion OBI carbon fiducial-based setup can improve localization accuracy with minimal imaging artifacts. With increased localization accuracy, setup uncertainties can be reduced from 8mm using OBI bone matching to 3mm using OBI fiducial matching for PBI treatment. This work demonstrates the feasibility of utilizing carbon fiducials to increase localization accuracy to the lumpectomy cavity for PBI. This may be particularly attractive for localization in the setting of proton therapy and other scenarios

SU-E-J-37: Feasibility of Utilizing Carbon Fiducials to Increase Localization Accuracy of Lumpectomy Cavity for Partial Breast Irradiation

Energy Technology Data Exchange (ETDEWEB)

Zhang, Y; Hieken, T; Mutter, R; Park, S; Yan, E; Brinkmann, D; Pafundi, D [Mayo Clinic, Rochester, MN (United States)

2015-06-15

Purpose To investigate the feasibility of utilizing carbon fiducials to increase localization accuracy of lumpectomy cavity for partial breast irradiation (PBI). Methods Carbon fiducials were placed intraoperatively in the lumpectomy cavity following resection of breast cancer in 11 patients. The patients were scheduled to receive whole breast irradiation (WBI) with a boost or 3D-conformal PBI. WBI patients were initially setup to skin tattoos using lasers, followed by orthogonal kV on-board-imaging (OBI) matching to bone per clinical practice. Cone beam CT (CBCT) was acquired weekly for offline review. For the boost component of WBI and PBI, patients were setup with lasers, followed by OBI matching to fiducials, with final alignment by CBCT matching to fiducials. Using carbon fiducials as a surrogate for the lumpectomy cavity and CBCT matching to fiducials as the gold standard, setup uncertainties to lasers, OBI bone, OBI fiducials, and CBCT breast were compared. Results Minimal imaging artifacts were introduced by fiducials on the planning CT and CBCT. The fiducials were sufficiently visible on OBI for online localization. The mean magnitude and standard deviation of setup errors were 8.4mm ± 5.3 mm (n=84), 7.3mm ± 3.7mm (n=87), 2.2mm ± 1.6mm (n=40) and 4.8mm ± 2.6mm (n=87), for lasers, OBI bone, OBI fiducials and CBCT breast tissue, respectively. Significant migration occurred in one of 39 implanted fiducials in a patient with a large postoperative seroma. Conclusion OBI carbon fiducial-based setup can improve localization accuracy with minimal imaging artifacts. With increased localization accuracy, setup uncertainties can be reduced from 8mm using OBI bone matching to 3mm using OBI fiducial matching for PBI treatment. This work demonstrates the feasibility of utilizing carbon fiducials to increase localization accuracy to the lumpectomy cavity for PBI. This may be particularly attractive for localization in the setting of proton therapy and other scenarios

The mitigating effect of calcification-dependent of utilization of inorganic carbon of Chara vulgaris Linn on NH4-N toxicity.

Science.gov (United States)

Wang, Heyun; Ni, Leyi; Xie, Ping

2013-09-01

Increased ammonium (NH4-N) concentrations in water bodies have been reported to adversely affect the dominant species of submersed vegetation in meso-eutrophic waters worldwide. However calcareous plants were lowly sensitive to NH4-N toxicity. In order to make clear the function of calcification in the tolerance of calcareous plants to NH4-N stress, we studied the effects of increased HCO3(-) and additional NH4-N on calcification and utilization of dissolve inorganic carbon (DIC) in Chara vulgaris Linn in a 7-d sub-acute experiment (light:dark 12:12h) carried out in an open experimental system in lab. Results revealed that calcification was dependent of utilization of dissolve inorganic carbon. Additional HCO3(-) significantly decreased the increase of pH while additional NH4-N did not. And additional HCO3(-) significantly improved calcification while NH4-N did in versus in relation to the variation of DIC concentration. However, addition of both HCO3(-) and NH4-N increased utilization of DIC. This resulted in calcification to utilization of DIC ratio decreased under additional NH4-N condition while increased under additional HCO3(-) conditions in response to the variation of solution pH. In the present study, external HCO3(-) decreased the increase of solution pH by increasing calcification, which correspondingly mitigated the toxic effect of high NH4-N. And we argue that the mitigating effect of increased HCO3(-) on NH4-N toxicity is dependent of plant calcification, and it is a positive feedback mechanism, potentially leading to the dominance of calcareous plants in meso-eutrophic water bodies. Copyright © 2013 Elsevier Ltd. All rights reserved.

Utilization Of Carbon Nanotubes In Electromagnetic Wave Detectors

Directory of Open Access Journals (Sweden)

Muhammad Hanis Zakariah

2017-08-01

Full Text Available Direct detection of hydrocarbon by an active source using electromagnetic (EM energy termed seabed logging (SBL has shown very promising results. However, currently available electromagnetic wave technology has a number of challenges include sensitivity and frequency matching. This paper presents development of the carbon nanotubes (CNTs as electromagnetic wave detector due to outstanding properties of carbon nanotubes. They are currently one of the desired materials for advanced technologies. Two types of detectors were developed in this work, carbon nanotube-based (D1 and without nanotube-based (D2 detectors. Various configuration and arrangement for each type of detector were investigated to determine the one with the highest detection measurement and stability of frequency stability of detection system. It was found that 20 turn-coils coil placed at its centre gives the maximum detection of induction voltage, 39.61 mV. However, the 20 turn- coils with CNTs which gives 36.50 mV is the preferred EM detectors due to the stability in frequency of the detection system.

Chemoprevention utility of silibinin and Cdk4 pathway inhibition in Apc−/+ mice

International Nuclear Information System (INIS)

Karim, Baktiar O; Rhee, Ki-Jong; Liu, Guosheng; Zheng, Dongfeng; Huso, David L

2013-01-01

Colorectal cancer (CRC) is the second leading cause of death from cancer in the United States. Colorectal cancers have a prolonged latency following initiation that may span decades providing ample time for implementing a chemoprevention strategy that could block or reverse the progression to CRC. Cdk4 pathway alterations have been linked to a number of cancers including CRC. In these experiments we focused on the Cdk4 pathway and its role in intestinal tumorigenesis as a possible target in chemoprevention strategies. We evaluated the effect of Cdk4 blockade on the prevention of intestinal tumor formation by crossing Cdk4 −/− mice to Apc −/+ mice. In addition, we tested the effect of the dietary compound silibinin on the Cdk4 pathway in Apc −/+ mice and HT-29 colon cancer cells in culture. Cdk4 −/− mice backcrossed to Apc −/+ mice reduced intestinal adenoma formation compared to Apc −/+ controls. Silibinin effectively targeted the Cdk4 pathway causing hypophosphorylation of the retinoblastoma protein, inhibited cell growth, and induced apoptosis. As a result silibinin blocked the development of intestinal adenomas by 52% in this genetic model (Apc −/+ mice) of early events in colorectal cancer formation. No toxic abnormalities were detected in mice which received silibinin. Modification of the Cdk4 pathway using a natural plant-derived compound such as silibinin may be a useful chemopreventive strategy for colorectal carcinomas

Funding pathways to a low-carbon transition

Science.gov (United States)

Foulds, Chris; Christensen, Toke Haunstrup

2016-07-01

The framing of funding programmes can sustain existing ways of conceptualizing particular problems, as well as create new ones. Yet, without more prominent roles for social sciences and humanities, the techno-economic conceptualization of energy consumers could hinder long-term low-carbon aspirations.

Microbial methane from in situ biodegradation of coal and shale: A review and reevaluation of hydrogen and carbon isotope signatures

Science.gov (United States)

Vinson, David S.; Blair, Neal E.; Martini, Anna M.; Larter, Steve; Orem, William H.; McIntosh, Jennifer C.

2017-01-01

Stable carbon and hydrogen isotope signatures of methane, water, and inorganic carbon are widely utilized in natural gas systems for distinguishing microbial and thermogenic methane and for delineating methanogenic pathways (acetoclastic, hydrogenotrophic, and/or methylotrophic methanogenesis). Recent studies of coal and shale gas systems have characterized in situ microbial communities and provided stable isotope data (δD-CH4, δD-H2O, δ13C-CH4, and δ13C-CO2) from a wider range of environments than available previously. Here we review the principal biogenic methane-yielding pathways in coal beds and shales and the isotope effects imparted on methane, document the uncertainties and inconsistencies in established isotopic fingerprinting techniques, and identify the knowledge gaps in understanding the subsurface processes that govern H and C isotope signatures of biogenic methane. We also compare established isotopic interpretations with recent microbial community characterization techniques, which reveal additional inconsistencies in the interpretation of microbial metabolic pathways in coal beds and shales. Collectively, the re-assessed data show that widely-utilized isotopic fingerprinting techniques neglect important complications in coal beds and shales.Isotopic fingerprinting techniques that combine δ13C-CH4 with δD-CH4 and/or δ13C-CO2have significant limitations: (1) The consistent ~ 160‰ offset between δD-H2O and δD-CH4 could imply that hydrogenotrophic methanogenesis is the dominant metabolic pathway in microbial gas systems. However, hydrogen isotopes can equilibrate between methane precursors and coexisting water, yielding a similar apparent H isotope signal as hydrogenotrophic methanogenesis, regardless of the actual methane formation pathway. (2) Non-methanogenic processes such as sulfate reduction, Fe oxide reduction, inputs of thermogenic methane, anaerobic methane oxidation, and/or formation water interaction can cause the apparent carbon

Carbon Alloys-Multi-functionalization

Energy Technology Data Exchange (ETDEWEB)

Yasuda, Eiichi [MSL, Tokyo Institute of Technology, Yokohama 226-8503 (Japan)], E-mail: yasuda.e.aa.@m.titech.ac.jp; Enami, Takashi; Hoteida, Nobuyuki [MSL, Tokyo Institute of Technology, Yokohama 226-8503 (Japan); Lanticse-Diaz, L.J. [University of the Philippines (Philippines); Tanabe, Yasuhiro [Nagoya University (Japan); Akatsu, Takashi [MSL, Tokyo Institute of Technology, Yokohama 226-8503 (Japan)

2008-02-25

Last decade after our proposal of the 'Carbon Alloys' concept, many different kinds of Carbon Alloys, such as carbon nanotubes, carbon nanofibers, graphene sheet with magnetism, semi-conducting BCN compounds, graphite intercalation compounds, exfoliated carbon fiber, etc. have been found and developed. To extend the concept further, it is important to make it into intelligent materials by incorporating multiple functions. One example of the multi-functionalization is the development of homo-atomic Carbon Alloys from glassy carbon (GC) that exhibits high electrical conductivity and low gas permeability after treatment at critical conditions. Glassy carbon underwent metamorphosis to graphite spheres at HIP condition, and improved resistance to oxidation after alloying with Ta. The other one is shape utilization of the nano-sized carbon by understanding the effect of its large surfaces or interfaces in nanotechnology treatment. Recently carbon nanofiber was produced by polymer blend technology (PB) which was proposed by Prof. A. Oya during the Carbon Alloy project and progressed into intelligent carbon nanofiber (CNF) materials. CNF is combined into the polymer composites which is a candidate material for the bipolar separator in fuel cell. The superior properties, i.e., high electrical conductivity, high modulus, high strength, etc., of the CNF is being utilized in the preparation of this polymer composite.

Bioreactors for fixation and effective utilization of carbon dioxide gas. Tansan gas no koteiter dot yuko riyo no tame no bio reactor

Energy Technology Data Exchange (ETDEWEB)

Miyamoto, K. (Osaka University, Osaka (Japan). Faculty of Pharmaceutical Science); Benemann, J. (California University, CA (USA))

1991-06-01

As for a preventive countermeasure against the global warming, experiments and studies have been conducted on the bioreactors to fix carbon dioxide gas recovered from the concentric and large scale generating sources such as thermal power plamts in a form of carbohydrate by means of the culture of microbial algae. By using the Vertical Tube Reactors (VTR) culturing apparatus, a variety of microbial algae were cultivated and experiments were performed on the relationship of biomass productivity and absorption rate of carbon dioxide gas indoors and outdoors. Consequently, it was found that when the flow rate of carbon dioxide gas is adjusted to make the biomass productivity of filament type Nostoc maximum,the inlet and outlet concentrations of carbon dioxide gas were 0.7% and 0.05% respectively with the absorption rate of more than 90%. From the standpoint of fixation and effective utilization of carbon dioxide gas, the above rate of removal is one of the important parameters and it will be necessary in future to compare the rates of removal of carbon dioxide gas among various types of bioreactors as a function of operating condition. 9 refs., 6 figs., 2 tabs.

Carbon activity meter

International Nuclear Information System (INIS)

Roy, P.; Krankota, J.L.

1975-01-01

A carbon activity meter utilizing an electrochemical carbon cell with gaseous reference electrodes having particular application for measuring carbon activity in liquid sodium for the LMFBR project is described. The electrolyte container is electroplated with a thin gold film on the inside surface thereof, and a reference electrode consisting of CO/CO 2 gas is used. (U.S.)

Moving from Outsider to Insider: Peer Status and Partnerships between Electricity Utilities and Residential Consumers

Science.gov (United States)

Morris, Peter; Buys, Laurie; Vine, Desley

2014-01-01

An electricity demand reduction project based on comprehensive residential consumer engagement was established within an Australian community in 2008. By 2011, both the peak demand and grid supplied electricity consumption had decreased to below pre-intervention levels. This case study research explored the relationship developed between the utility, community and individual consumer from the residential customer perspective through qualitative research of 22 residential households. It is proposed that an energy utility can be highly successful at peak demand reduction by becoming a community member and a peer to residential consumers and developing the necessary trust, access, influence and partnership required to create the responsive environment to change. A peer-community approach could provide policymakers with a pathway for implementing pro-environmental behaviour for low carbon communities, as well as peak demand reduction, thereby addressing government emission targets while limiting the cost of living increases from infrastructure expenditure. PMID:24979234

Preparation of hollow mesoporous carbon spheres and their performances for electrochemical applications

Science.gov (United States)

Ariyanto, T.; Zhang, G. R.; Kern, A.; Etzold, B. J. M.

2018-03-01

Hollow carbon materials have received intensive attention for energy storage/conversion applications due to their attractive properties of high conductivity, high surface area, large void and short diffusion pathway. In this work, a novel hollow mesoporous material based on carbide-derived carbon (CDC) is presented. CDC is a new class of carbon material synthesized by the selective extraction of metals from metal carbides. With a two-stage extraction procedure of carbides with chlorine, firstly hybrid core-shell carbon particles were synthesized, i.e. mesoporous/graphitic carbon shells covering microporous/amorphous carbon cores. The amorphous cores were then selectively removed from particles by a careful oxidative treatment utilizing its low thermal characters while the more stable carbon shells remained, thus resulting hollow particles. The characterization methods (e.g. N2 sorption, Raman spectroscopy, temperature-programmed oxidation and SEM) proved the successful synthesis of the aspired material. In electric double-layer capacitor (EDLC) testing, this novel hollow core material showed a remarkable enhancement of EDLC’s rate handling ability (75% at a high scan rate) with respect to an entirely solid-mesoporous material. Furthermore, as a fuel cell catalyst support the material showed higher Pt mass activity (a factor of 1.8) compared to a conventional carbon support for methanol oxidation without noticeably decreasing activity in a long-term testing. Therefore, this carbon nanostructure shows great promises as efficient electrode materials for energy storage and conversion systems.

Chemical Rescue of Enzymes: Proton Transfer in Mutants of Human Carbonic Anhydrase II

Science.gov (United States)

Maupin, C. Mark; Castillo, Norberto; Taraphder, Srabani; Tu, Chingkuang; McKenna, Robert; Silverman, David N.; Voth, Gregory A.

2011-01-01

In human carbonic anhydrase II (HCA II) the mutation of position 64 from histidine to alanine (H64A) disrupts the rate limiting proton transfer (PT) event, resulting in a reduction of the catalytic activity of the enzyme as compared to the wild-type. Potential of mean force (PMF) calculations utilizing the multistate empirical valence bond (MS-EVB) methodology for H64A HCA II give a PT free energy barrier significantly higher than that found in the wild-type enzyme. This high barrier, determined in the absence of exogenous buffer and assuming no additional ionizable residues in the PT pathway, indicates the likelihood of alternate enzyme pathways that utilize either ionizable enzyme residues (self-rescue) and/or exogenous buffers (chemical rescue). It has been shown experimentally that the catalytic activity of H64A HCA II can be chemically rescued to near wild type levels by the addition of the exogenous buffer 4-methylimidazole (4MI). Crystallographic studies have identified two 4MI binding sites, yet site specific mutations intended to disrupt 4MI binding have demonstrated these sites to be non-productive. In the present work MS-EVB simulations show that binding of 4MI near Thr199 in the H64A HCA II mutant, a binding site determined by NMR spectroscopy, results in a viable chemical rescue pathway. Additional viable rescue pathways are also identified where 4MI acts as a proton transport intermediary from the active site to ionizable residues on the rim of the active site, revealing a probable mode of action for the chemical rescue pathway PMID:21452838

Carbon Isotope Chemistry in Molecular Clouds

Science.gov (United States)

Robertson, Amy N.; Willacy, Karen

2012-01-01

Few details of carbon isotope chemistry are known, especially the chemical processes that occur in astronomical environments like molecular clouds. Observational evidence shows that the C-12/C-13 abundance ratios vary due to the location of the C-13 atom within the molecular structure. The different abundances are a result of the diverse formation pathways that can occur. Modeling can be used to explore the production pathways of carbon molecules in an effort to understand and explain the chemical evolution of molecular clouds.

UTILIZATION OF PINEAPPLE WASTE AS CARBON SOURCE

Directory of Open Access Journals (Sweden)

Abdullah Moch Busairi

2012-02-01

Full Text Available The liquid pineapple waste contains mainly sucrose, glucose, fructose and other nutrients. It therefore can potentially be used as carbon source for organic acid fermentation.  The objective of this work is to evaluate the use of pineapple waste as substrate for lactic acid fermentation under variables of aerobic, anaerobic condition and pH controlling. Initial results showed that the liquid pineapple waste can be used as carbon source for lactic acid fermentation using Lactobacillus delbrueckii. In the anaerobic condition growth of bacteria and lactic acid production better than aerobic condition. In the anaerobic condition and the controlled pH  the production of lactic acid are found to be 54.79 g/l  (78.27% yield at  40oC, pH 6, 50 rpm and 70 g/l sugar concentration.  In contrast, only 13.87g/l lactic acid produced if the fermentation pH was not controlled even though the fermentation parameters were kept at the same conditions

Predicting pathway cross-talks in ankylosing spondylitis through investigating the interactions among pathways.

Science.gov (United States)

Gu, Xiang; Liu, Cong-Jian; Wei, Jian-Jie

2017-11-13

Given that the pathogenesis of ankylosing spondylitis (AS) remains unclear, the aim of this study was to detect the potentially functional pathway cross-talk in AS to further reveal the pathogenesis of this disease. Using microarray profile of AS and biological pathways as study objects, Monte Carlo cross-validation method was used to identify the significant pathway cross-talks. In the process of Monte Carlo cross-validation, all steps were iterated 50 times. For each run, detection of differentially expressed genes (DEGs) between two groups was conducted. The extraction of the potential disrupted pathways enriched by DEGs was then implemented. Subsequently, we established a discriminating score (DS) for each pathway pair according to the distribution of gene expression levels. After that, we utilized random forest (RF) classification model to screen out the top 10 paired pathways with the highest area under the curve (AUCs), which was computed using 10-fold cross-validation approach. After 50 bootstrap, the best pairs of pathways were identified. According to their AUC values, the pair of pathways, antigen presentation pathway and fMLP signaling in neutrophils, achieved the best AUC value of 1.000, which indicated that this pathway cross-talk could distinguish AS patients from normal subjects. Moreover, the paired pathways of SAPK/JNK signaling and mitochondrial dysfunction were involved in 5 bootstraps. Two paired pathways (antigen presentation pathway and fMLP signaling in neutrophil, as well as SAPK/JNK signaling and mitochondrial dysfunction) can accurately distinguish AS and control samples. These paired pathways may be helpful to identify patients with AS for early intervention.

The emergence and early evolution of biological carbon-fixation.

Science.gov (United States)

Braakman, Rogier; Smith, Eric

2012-01-01

The fixation of CO₂ into living matter sustains all life on Earth, and embeds the biosphere within geochemistry. The six known chemical pathways used by extant organisms for this function are recognized to have overlaps, but their evolution is incompletely understood. Here we reconstruct the complete early evolutionary history of biological carbon-fixation, relating all modern pathways to a single ancestral form. We find that innovations in carbon-fixation were the foundation for most major early divergences in the tree of life. These findings are based on a novel method that fully integrates metabolic and phylogenetic constraints. Comparing gene-profiles across the metabolic cores of deep-branching organisms and requiring that they are capable of synthesizing all their biomass components leads to the surprising conclusion that the most common form for deep-branching autotrophic carbon-fixation combines two disconnected sub-networks, each supplying carbon to distinct biomass components. One of these is a linear folate-based pathway of CO₂ reduction previously only recognized as a fixation route in the complete Wood-Ljungdahl pathway, but which more generally may exclude the final step of synthesizing acetyl-CoA. Using metabolic constraints we then reconstruct a "phylometabolic" tree with a high degree of parsimony that traces the evolution of complete carbon-fixation pathways, and has a clear structure down to the root. This tree requires few instances of lateral gene transfer or convergence, and instead suggests a simple evolutionary dynamic in which all divergences have primary environmental causes. Energy optimization and oxygen toxicity are the two strongest forces of selection. The root of this tree combines the reductive citric acid cycle and the Wood-Ljungdahl pathway into a single connected network. This linked network lacks the selective optimization of modern fixation pathways but its redundancy leads to a more robust topology, making it more

The emergence and early evolution of biological carbon-fixation.

Directory of Open Access Journals (Sweden)

Rogier Braakman

Full Text Available The fixation of CO₂ into living matter sustains all life on Earth, and embeds the biosphere within geochemistry. The six known chemical pathways used by extant organisms for this function are recognized to have overlaps, but their evolution is incompletely understood. Here we reconstruct the complete early evolutionary history of biological carbon-fixation, relating all modern pathways to a single ancestral form. We find that innovations in carbon-fixation were the foundation for most major early divergences in the tree of life. These findings are based on a novel method that fully integrates metabolic and phylogenetic constraints. Comparing gene-profiles across the metabolic cores of deep-branching organisms and requiring that they are capable of synthesizing all their biomass components leads to the surprising conclusion that the most common form for deep-branching autotrophic carbon-fixation combines two disconnected sub-networks, each supplying carbon to distinct biomass components. One of these is a linear folate-based pathway of CO₂ reduction previously only recognized as a fixation route in the complete Wood-Ljungdahl pathway, but which more generally may exclude the final step of synthesizing acetyl-CoA. Using metabolic constraints we then reconstruct a "phylometabolic" tree with a high degree of parsimony that traces the evolution of complete carbon-fixation pathways, and has a clear structure down to the root. This tree requires few instances of lateral gene transfer or convergence, and instead suggests a simple evolutionary dynamic in which all divergences have primary environmental causes. Energy optimization and oxygen toxicity are the two strongest forces of selection. The root of this tree combines the reductive citric acid cycle and the Wood-Ljungdahl pathway into a single connected network. This linked network lacks the selective optimization of modern fixation pathways but its redundancy leads to a more robust topology

Carbon transfer from dissolved organic carbon to the cladoceran Bosmina: a mesocosm study

Directory of Open Access Journals (Sweden)

Tang Yali

2017-01-01

Full Text Available A mesocosm study illuminated possible transfer pathways for dissolved organic carbon from the water column to zooplankton. Organic carbon was added as 13C enriched glucose to 15 mesocosms filled with natural lake water. Stable isotope analysis and phospholipid fatty acids-based stable isotope probing were used to trace the incorporation of 13C into the cladoceran Bosmina and its potential food items. Glucose-C was shown to be assimilated into phytoplankton (including fungi and heterotrophic protists, bacteria and Bosmina, all of which became enriched with 13C during the experiment. The study suggests that bacteria play an important role in the transfer of glucose-C to Bosmina. Furthermore, osmotic algae, fungi and heterotrophic protists might also contribute to the isotopic signature changes observed in Bosmina. These findings help to clarify the contribution of dissolved organic carbon to zooplankton and its potential pathways.

Synergy between methylerythritol phosphate pathway and mevalonate pathway for isoprene production in Escherichia coli.

Science.gov (United States)

Yang, Chen; Gao, Xiang; Jiang, Yu; Sun, Bingbing; Gao, Fang; Yang, Sheng

2016-09-01

Isoprene, a key building block of synthetic rubber, is currently produced entirely from petrochemical sources. In this work, we engineered both the methylerythritol phosphate (MEP) pathway and the mevalonate (MVA) pathway for isoprene production in E. coli. The synergy between the MEP pathway and the MVA pathway was demonstrated by the production experiment, in which overexpression of both pathways improved the isoprene yield about 20-fold and 3-fold, respectively, compared to overexpression of the MEP pathway or the MVA pathway alone. The (13)C metabolic flux analysis revealed that simultaneous utilization of the two pathways resulted in a 4.8-fold increase in the MEP pathway flux and a 1.5-fold increase in the MVA pathway flux. The synergy of the dual pathway was further verified by quantifying intracellular flux responses of the MEP pathway and the MVA pathway to fosmidomycin treatment and mevalonate supplementation. Our results strongly suggest that coupling of the complementary reducing equivalent demand and ATP requirement plays an important role in the synergy of the dual pathway. Fed-batch cultivation of the engineered strain overexpressing the dual pathway resulted in production of 24.0g/L isoprene with a yield of 0.267g/g of glucose. The synergy of the MEP pathway and the MVA pathway also successfully increased the lycopene productivity in E. coli, which demonstrates that it can be used to improve the production of a broad range of terpenoids in microorganisms. Copyright © 2016 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Effect of temperature on the reaction pathway of calcium carbonate formation via precursor phases

Science.gov (United States)

Purgstaller, Bettina; Mavromatis, Vasileios; Konrad, Florian; Dietzel, Martin

2016-04-01

It has been earlier postulated that some biogenic and sedimentary calcium carbonate (CaCO3) minerals (e.g. calcite and aragonite) are secondary in origin and have originally formed via a metastable calcium carbonate precursor phase (e.g. amorphous CaCO3, [1-2]). Such formation pathways are likely affected by various physicochemical parameters including aqueous Mg and temperature. In an effort to improve our understanding on the formation mechanism of CaCO3 minerals, precipitation experiments were carried out by the addition of a 0.6 M (Ca,Mg)Cl2 solution at distinct Mg/Ca ratios (1/4 and 1/8) into a 1 M NaHCO3 solution under constant pH conditions(8.3 ±0.1). The formation of CaCO3 was systematically examined as a function of temperature (6, 12, 18 and 25 ±0.3° C). During the experimental runs mineral precipitation was monitored by in situ Raman spectroscopy as well as by continuous sampling and analyzing of precipitates and reactive solutions. The results revealed two pathways of CaCO3 formation depending on the initial Mg/Ca ratio and temperature: (i) In experiments with a Mg/Ca ratio of 1/4 at ≤ 12° C as well as in experiments with a Mg/Ca ratio of 1/8 at ≤ 18° C, ikaite (CaCO3 6H2O) acts as a precursor phase for aragonite formation. (ii) In contrast higher temperatures induced the formation of Mg-rich amorphous CaCO3 (Mg-ACC) which was subsequently transformed to Mg-rich calcite. In situ Raman spectra showed that the transformation of Mg-ACC to Mg-calcite occurs at a higher rate (˜ 8 min) compared to that of ikaite to aragonite (> 2 h). Thus, the formation of aragonite rather than of Mg-calcite occurs due to the slower release of Ca2+and CO32- ions into the Mg-rich reactive solution during retarded ikaite dissolution. This behavior is generally consistent with the observation that calcite precipitation is inhibited at elevated aqueous Mg/Ca ratios. [1] Addadi L., Raz S. and Weiner S. (2003) Advanced Materials 15, 959-970. [2] Rodriguez-Blanco J. D

Current and Future United States Light-Duty Vehicle Pathways: Cradle-to-Grave Lifecycle Greenhouse Gas Emissions and Economic Assessment

Energy Technology Data Exchange (ETDEWEB)

Elgowainy, Amgad [Argonne National Laboratory, Argonne, Illinois 60439, United States; Han, Jeongwoo [Argonne National Laboratory, Argonne, Illinois 60439, United States; Ward, Jacob [United States Department of Energy, Washington, D.C. 20585, United States; Joseck, Fred [United States Department of Energy, Washington, D.C. 20585, United States; Gohlke, David [Argonne National Laboratory, Argonne, Illinois 60439, United States; Lindauer, Alicia [United States Department of Energy, Washington, D.C. 20585, United States; Ramsden, Todd [National Renewable Energy Laboratory, Golden, Colorado 80401, United States; Biddy, Mary [National Renewable Energy Laboratory, Golden, Colorado 80401, United States; Alexander, Mark [Electric Power Research Institute, Palo; Barnhart, Steven [FCA US LLC, Auburn Hills, Michigan 48326, United States; Sutherland, Ian [General Motors, Pontiac, Michigan 48340, United States; Verduzco, Laura [Chevron Corporation, Richmond, California 94802, United States; Wallington, Timothy J. [Ford Motor Company, Dearborn, Michigan 48121, United States

2018-01-30

This article presents a cradle-to-grave (C2G) assessment of greenhouse gas (GHG) emissions and costs for current (2015) and future (2025-2030) light-duty vehicles. The analysis addressed both fuel cycle and vehicle manufacturing cycle for the following vehicle types: gasoline and diesel internal combustion engine vehicles (ICEVs), flex fuel vehicles, compressed natural gas (CNG) vehicles, hybrid electric vehicles (HEVs), hydrogen fuel cell electric vehicles (FCEVs), battery electric vehicles (BEVs), and plug-in hybrid electric vehicles (PHEVs). Gasoline ICEVs using current technology have C2G emissions of ~450 gCO2e/mi (grams of carbon dioxide equivalents per mile), while C2G emissions from HEVs, PHEVs, H2 FCEVs, and BEVs range from 300-350 gCO2e/mi. Future vehicle efficiency gains are expected to reduce emissions to ~350 gCO2/mi for ICEVs and ~250 gCO2e/mi for HEVs, PHEVs, FCEVs, and BEVs. Utilizing low-carbon fuel pathways yields GHG reductions more than double those achieved by vehicle efficiency gains alone. Levelized costs of driving (LCDs) are in the range $0.25-$1.00/mi depending on time frame and vehicle-fuel technology. In all cases, vehicle cost represents the major (60-90%) contribution to LCDs. Currently, HEV and PHEV petroleum-fueled vehicles provide the most attractive cost in terms of avoided carbon emissions, although they offer lower potential GHG reductions. The ranges of LCD and cost of avoided carbon are narrower for the future technology pathways, reflecting the expected economic competitiveness of these alternative vehicles and fuels.

The self-renewal signaling pathways utilized by gastric cancer stem cells.

Science.gov (United States)

Fu, Ying; Li, Hui; Hao, Xishan

2017-04-01

Gastric cancer is a leading cause of cancer-related mortality worldwide. Cancer stem cells are the source of tumor recurrence and metastasis. Self-renewal is a marker of cancer stem cells and also the basis of long-lasting survival and tumor progression. Although the mechanism of gastric cancer stem cell self-renewal is not clear, there are several signaling pathways and environmental factors known to be involved. This mini review describes recent developments in the self-renewal signaling pathway of gastric cancer stem cell research. Advancements made in this field of research will likely support the development of novel therapeutic strategies for gastric cancer.

Waste-to-wheel analysis of anaerobic-digestion-based renewable natural gas pathways with the GREET model

International Nuclear Information System (INIS)

Han, J.; Mintz, M.; Wang, M.

2011-01-01

In 2009, manure management accounted for 2,356 Gg or 107 billion standard cubic ft of methane (CH 4 ) emissions in the United States, equivalent to 0.5% of U.S. natural gas (NG) consumption. Owing to the high global warming potential of methane, capturing and utilizing this methane source could reduce greenhouse gas (GHG) emissions. The extent of that reduction depends on several factors - most notably, how much of this manure-based methane can be captured, how much GHG is produced in the course of converting it to vehicular fuel, and how much GHG was produced by the fossil fuel it might displace. A life-cycle analysis was conducted to quantify these factors and, in so doing, assess the impact of converting methane from animal manure into renewable NG (RNG) and utilizing the gas in vehicles. Several manure-based RNG pathways were characterized in the GREET (Greenhouse gases, Regulated Emissions, and Energy use in Transportation) model, and their fuel-cycle energy use and GHG emissions were compared to petroleum-based pathways as well as to conventional fossil NG pathways. Results show that despite increased total energy use, both fossil fuel use and GHG emissions decline for most RNG pathways as compared with fossil NG and petroleum. However, GHG emissions for RNG pathways are highly dependent on the specifics of the reference case, as well as on the process energy emissions and methane conversion factors assumed for the RNG pathways. The most critical factors are the share of flared controllable CH 4 and the quantity of CH 4 lost during NG extraction in the reference case, the magnitude of N 2 O lost in the anaerobic digestion (AD) process and in AD residue, and the amount of carbon sequestered in AD residue. In many cases, data for these parameters are limited and uncertain. Therefore, more research is needed to gain a better understanding of the range and magnitude of environmental benefits from converting animal manure to RNG via AD.

Waste-to-wheel analysis of anaerobic-digestion-based renewable natural gas pathways with the GREET model.

Energy Technology Data Exchange (ETDEWEB)

Han, J.; Mintz, M.; Wang, M. (Energy Systems)

2011-12-14

In 2009, manure management accounted for 2,356 Gg or 107 billion standard cubic ft of methane (CH{sub 4}) emissions in the United States, equivalent to 0.5% of U.S. natural gas (NG) consumption. Owing to the high global warming potential of methane, capturing and utilizing this methane source could reduce greenhouse gas (GHG) emissions. The extent of that reduction depends on several factors - most notably, how much of this manure-based methane can be captured, how much GHG is produced in the course of converting it to vehicular fuel, and how much GHG was produced by the fossil fuel it might displace. A life-cycle analysis was conducted to quantify these factors and, in so doing, assess the impact of converting methane from animal manure into renewable NG (RNG) and utilizing the gas in vehicles. Several manure-based RNG pathways were characterized in the GREET (Greenhouse gases, Regulated Emissions, and Energy use in Transportation) model, and their fuel-cycle energy use and GHG emissions were compared to petroleum-based pathways as well as to conventional fossil NG pathways. Results show that despite increased total energy use, both fossil fuel use and GHG emissions decline for most RNG pathways as compared with fossil NG and petroleum. However, GHG emissions for RNG pathways are highly dependent on the specifics of the reference case, as well as on the process energy emissions and methane conversion factors assumed for the RNG pathways. The most critical factors are the share of flared controllable CH{sub 4} and the quantity of CH{sub 4} lost during NG extraction in the reference case, the magnitude of N{sub 2}O lost in the anaerobic digestion (AD) process and in AD residue, and the amount of carbon sequestered in AD residue. In many cases, data for these parameters are limited and uncertain. Therefore, more research is needed to gain a better understanding of the range and magnitude of environmental benefits from converting animal manure to RNG via AD.

Pathways to Aggression in Urban Elementary School Youth

Science.gov (United States)

Ozkol, Hivren; Zucker, Marla; Spinazzola, Joseph

2011-01-01

This study examined the pathways from violence exposure to aggressive behaviors in urban, elementary school youth. We utilized structural equation modeling to examine putative causal pathways between children's exposure to violence, development of posttraumatic stress symptoms, permissive attitudes towards violence, and engagement in aggressive…

Nano-risk Science: application of toxicogenomics in an adverse outcome pathway framework for risk assessment of multi-walled carbon nanotubes.

Science.gov (United States)

Labib, Sarah; Williams, Andrew; Yauk, Carole L; Nikota, Jake K; Wallin, Håkan; Vogel, Ulla; Halappanavar, Sabina

2016-03-15

A diverse class of engineered nanomaterials (ENMs) exhibiting a wide array of physical-chemical properties that are associated with toxicological effects in experimental animals is in commercial use. However, an integrated framework for human health risk assessment (HHRA) of ENMs has yet to be established. Rodent 2-year cancer bioassays, clinical chemistry, and histopathological endpoints are still considered the 'gold standard' for detecting substance-induced toxicity in animal models. However, the use of data derived from alternative toxicological tools, such as genome-wide expression profiling and in vitro high-throughput assays, are gaining acceptance by the regulatory community for hazard identification and for understanding the underlying mode-of-action. Here, we conducted a case study to evaluate the application of global gene expression data in deriving pathway-based points of departure (PODs) for multi-walled carbon nanotube (MWCNT)-induced lung fibrosis, a non-cancer endpoint of regulatory importance. Gene expression profiles from the lungs of mice exposed to three individual MWCNTs with different physical-chemical properties were used within the framework of an adverse outcome pathway (AOP) for lung fibrosis to identify key biological events linking MWCNT exposure to lung fibrosis. Significantly perturbed pathways were categorized along the key events described in the AOP. Benchmark doses (BMDs) were calculated for each perturbed pathway and were used to derive transcriptional BMDs for each MWCNT. Similar biological pathways were perturbed by the different MWCNT types across the doses and post-exposure time points studied. The pathway BMD values showed a time-dependent trend, with lower BMDs for pathways perturbed at the earlier post-exposure time points (24 h, 3d). The transcriptional BMDs were compared to the apical BMDs derived by the National Institute for Occupational Safety and Health (NIOSH) using alveolar septal thickness and fibrotic lesions

Gluconeogenesis from labeled carbon: estimating isotope dilution

International Nuclear Information System (INIS)

Kelleher, J.K.

1986-01-01

To estimate the rate of gluconeogenesis from steady-state incorporation of labeled 3-carbon precursors into glucose, isotope dilution must be considered so that the rate of labeling of glucose can be quantitatively converted to the rate of gluconeogenesis. An expression for the value of this isotope dilution can be derived using mathematical techniques and a model of the tricarboxylic acid (TCA) cycle. The present investigation employs a more complex model than that used in previous studies. This model includes the following pathways that may affect the correction for isotope dilution: 1) flux of 3-carbon precursor to the oxaloacetate pool via acetyl-CoA and the TCA cycle; 2) flux of 4- or 5-carbon compounds into the TCA cycle; 3) reversible flux between oxaloacetate (OAA) and pyruvate and between OAA and fumarate; 4) incomplete equilibrium between OAA pools; and 5) isotope dilution of 3-carbon tracers between the experimentally measured pool and the precursor for the TCA-cycle OAA pool. Experimental tests are outlined which investigators can use to determine whether these pathways are significant in a specific steady-state system. The study indicated that flux through these five pathways can significantly affect the correction for isotope dilution. To correct for the effects of these pathways an alternative method for calculating isotope dilution is proposed using citrate to relate the specific activities of acetyl-CoA and OAA

A Nanopore-Structured Nitrogen-Doped Biocarbon Electrocatalyst for Oxygen Reduction from Two-Step Carbonization of Lemna minor Biomass

Science.gov (United States)

Guo, Chaozhong; Li, Zhongbin; Niu, Lidan; Liao, Wenli; Sun, Lingtao; Wen, Bixia; Nie, Yunqing; Cheng, Jing; Chen, Changguo

2016-05-01

So far, the development of highly active and stable carbon-based electrocatalysts for oxygen reduction reaction (ORR) to replace commercial Pt/C catalyst is a hot topic. In this study, a new nanoporous nitrogen-doped carbon material was facilely designed by two-step pyrolysis of the renewable Lemna minor enriched in crude protein under a nitrogen atmosphere. Electrochemical measurements show that the onset potential for ORR on this carbon material is around 0.93 V (versus reversible hydrogen electrode), slightly lower than that on the Pt/C catalyst, but its cycling stability is higher compared to the Pt/C catalyst in an alkaline medium. Besides, the ORR at this catalyst approaches to a four-electron transfer pathway. The obtained ORR performance can be basically attributed to the formation of high contents of pyridinic and graphitic nitrogen atoms inside this catalyst. Thus, this work opens up the path in the ORR catalysis for the design of nitrogen-doped carbon materials utilizing aquatic plants as starting precursors.

Electrocatalysis of oxygen reduction on nitrogen-containing multi-walled carbon nanotube modified glassy carbon electrodes

International Nuclear Information System (INIS)

Vikkisk, Merilin; Kruusenberg, Ivar; Joost, Urmas; Shulga, Eugene; Tammeveski, Kaido

2013-01-01

Highlights: ► Pyrolysis in the presence of urea was used for nitrogen doping of carbon nanotubes. ► N-doped carbon nanotubes were used as catalysts for the oxygen reduction reaction. ► N-doped carbon material showed a high catalytic activity for ORR in alkaline media. ► N-containing CNT material is an attractive cathode catalyst for alkaline membrane fuel cells. - Abstract: The electrochemical reduction of oxygen was studied on nitrogen-doped multi-walled carbon nanotube (NCNT) modified glassy carbon (GC) electrodes employing the rotating disk electrode (RDE) method. Nitrogen doping was achieved by simple pyrolysis of the carbon nanotube material in the presence of urea. The surface morphology and composition of the NCNT samples were investigated by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The SEM images revealed a rather uniform distribution of NCNTs on the GC electrode substrate. The XPS analysis showed a successful doping of carbon nanotubes with nitrogen species. The RDE results revealed that in alkaline solution the N-doped nanotube materials showed a remarkable electrocatalytic activity towards oxygen reduction. At low overpotentials the reduction of oxygen followed a two-electron pathway on undoped carbon nanotube modified GC electrodes, whereas on NCNT/GC electrodes a four-electron pathway of O 2 reduction predominated. The results obtained are significant for the development of nitrogen-doped carbon-based cathodes for alkaline membrane fuel cells.

Silicon Utilizing Microbial Bioactivities in the Biosphere

Science.gov (United States)

Sen, M. M.; Das, S.

2012-12-01

Diatoms are unicellular eukaryotic algae and an important member of the silicon utilizing organisms, that generate ~20% of the ~100 billion metric tons of organic carbon produced through photosynthesis on Earth each year. Fragilariopsis is a dominating psychrophilic diatom genus in polar sea ice. The two species Fragilariopsis cylindrus and Fragilariopsis curta are able to grow and divide below freezing temperature. Antifreeze proteins (AFPs), involved in cold adaptation in several psychrophilic organisms, are widespread in this two polar species. Achanthes minutissima isolated as dominant diatom has degradable effects involving petroleum hydocarbons. Phaeodactylum tricornutum, have antibacterial activity and the fatty acid, eicosapentaenoic acid (EPA), has been identified as one compound responsible for this activity. Other antibacterial compounds are monounsaturated fatty acid (9Z)-hexadecenoic acid (palmitoleic acid; C16:1 n-7) and the relatively unusual polyunsaturated fatty acid (6Z, 9Z, 12Z)-hexadecatrienoic acid (HTA; C16:3 n-4). Both are active against Gram-positive bacteria and many Gram-negative pathogen. Palmitoleic acid is active at micro-molar concentrations, kills bacteria rapidly, and is highly active against multidrug-resistant Staphylococcus aureus. Domoic acid -a neurotoxin produced by Pseudo-nitzschia accumulates in marine invertebrates. Evidences of sea lion (Zalophus californianus) and human poisoning following consumption of contaminated blue mussels (Mytilus edulis) is mainly due to this toxin. Among the most prominent features described in human beings was memory impairment which led to the name Amnesic Shellfish Poisoning [ASP]. Silicon utilizing organisms can act as a bioindicator of environmental contamination, thus a rapid change in phytochelatins to both the increase in and the withdrawal of environmental Cd stress was found in Thalassiosira nordenskioeldii. Some of them also can produce biofuels particularly diatoms have significant

Comparative Genomics of Regulation of Fatty Acid and Branched-chain Amino Acid Utilization in Proteobacteria

Energy Technology Data Exchange (ETDEWEB)

Kazakov, Alexey E.; Rodionov, Dmitry A.; Arkin, Adam Paul; Dubchak, Inna; Gelfand, Mikhail S.; Alm, Eric

2008-10-31

Bacteria can use branched-chain amino acids (ILV, i.e. isoleucine, leucine, valine) and fatty acids (FA) as sole carbon and energy sources convering ILV into acetyl-CoA, propanoyl-CoA and propionyl-CoA, respectively. In this work, we used the comparative genomic approach to identify candidate transcriptional factors and DNA motifs that control ILV and FA utilization pathways in proteobacteria. The metabolic regulons were characterized based on the identification and comparison of candidate transcription factor binding sites in groups of phylogenetically related genomes. The reconstructed ILV/FA regulatory network demonstrates considerable variability and involves six transcriptional factors from the MerR, TetR and GntR families binding to eleven distinct DNA motifs. The ILV degradation genes in gamma- and beta-proteobacteria are mainly regulated by anovel regulator from the MerR family (e.g., LiuR in Pseudomonas aeruginosa) (40 species), in addition, the TetR-type regulator LiuQ was identified in some beta-proteobacteria (8 species). Besides the core set of ILV utilization genes, the LiuR regulon in some lineages is expanded to include genes from other metabolic pathways, such as the glyoxylate shunt and glutamate synthase in the Shewanella species. The FA degradation genes are controlled by four regulators including FadR in gamma-proteobacteria (34 species), PsrA in gamma- and beta-proteobacteria (45 species), FadP in beta-proteobacteria (14 species), and LiuR orthologs in alpha-proteobacteria (22 species). The remarkable variability of the regulatory systems associated with the FA degradation pathway is discussed from the functional and evolutionary points of view.

Reactivity of Single-Walled Carbon Nanotubes in the Diels-Alder Cycloaddition Reaction: Distortion-Interaction Analysis along the Reaction Pathway.

Science.gov (United States)

Li, Yingzi; Osuna, Sílvia; Garcia-Borràs, Marc; Qi, Xiaotian; Liu, Song; Houk, Kendall N; Lan, Yu

2016-08-26

Diels-Alder cycloaddition is one of the most powerful tools for the functionalization of single-walled carbon nanotubes (SWCNTs). Density functional theory at the B3-LYP level of theory has been used to investigate the reactivity of different-diameter SWCNTs (4-9,5) in Diels-Alder reactions with 1,3-butadiene; the reactivity was found to decrease with increasing SWCNT diameter. Distortion/interaction analysis along the whole reaction pathway was found to be a better way to explore the reactivity of this type of reaction. The difference in interaction energy along the reaction pathway is larger than that of the corresponding distortion energy. However, the distortion energy plots for these reactions show the same trend. Therefore, the formation of the transition state can be determined from the interaction energy. A lower interaction energy leads to an earlier transition state, which indicates a lower activation energy. The computational results also indicate that the original distortion of the SWCNTs leads to an increase in the reactivity of the SWCNTs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enterobacter sp. LU1 as a novel succinic acid producer - co-utilization of glycerol and lactose.

Science.gov (United States)

Podleśny, Marcin; Jarocki, Piotr; Wyrostek, Jakub; Czernecki, Tomasz; Kucharska, Jagoda; Nowak, Anna; Targoński, Zdzisław

2017-03-01

Succinic acid is an important C4-building chemical platform for many applications. A novel succinic acid-producing bacterial strain was isolated from goat rumen. Phylogenetic analysis based on the 16S rRNA sequence and physiological analysis indicated that the strain belongs to the genus Enterobacter. This is the first report of a wild bacterial strain from the genus Enterobacter that is capable of efficient succinic acid production. Co-fermentation of glycerol and lactose significantly improved glycerol utilization under anaerobic conditions, debottlenecking the utilization pathway of this valuable biodiesel waste product. Succinic acid production reached 35 g l -1 when Enterobacter sp. LU1 was cultured in medium containing 50 g l -1 of glycerol and 25 g l -1 of lactose as carbon sources. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Fermentation of Xylose Causes Inefficient Metabolic State Due to Carbon/Energy Starvation and Reduced Glycolytic Flux in Recombinant Industrial Saccharomyces cerevisiae

Science.gov (United States)

Matsushika, Akinori; Nagashima, Atsushi; Goshima, Tetsuya; Hoshino, Tamotsu

2013-01-01

In the present study, comprehensive, quantitative metabolome analysis was carried out on the recombinant glucose/xylose-cofermenting S. cerevisiae strain MA-R4 during fermentation with different carbon sources, including glucose, xylose, or glucose/xylose mixtures. Capillary electrophoresis time-of-flight mass spectrometry was used to determine the intracellular pools of metabolites from the central carbon pathways, energy metabolism pathways, and the levels of twenty amino acids. When xylose instead of glucose was metabolized by MA-R4, glycolytic metabolites including 3- phosphoglycerate, 2- phosphoglycerate, phosphoenolpyruvate, and pyruvate were dramatically reduced, while conversely, most pentose phosphate pathway metabolites such as sedoheptulose 7- phosphate and ribulose 5-phosphate were greatly increased. These results suggest that the low metabolic activity of glycolysis and the pool of pentose phosphate pathway intermediates are potential limiting factors in xylose utilization. It was further demonstrated that during xylose fermentation, about half of the twenty amino acids declined, and the adenylate/guanylate energy charge was impacted due to markedly decreased adenosine triphosphate/adenosine monophosphate and guanosine triphosphate/guanosine monophosphate ratios, implying that the fermentation of xylose leads to an inefficient metabolic state where the biosynthetic capabilities and energy balance are severely impaired. In addition, fermentation with xylose alone drastically increased the level of citrate in the tricarboxylic acid cycle and increased the aromatic amino acids tryptophan and tyrosine, strongly supporting the view that carbon starvation was induced. Interestingly, fermentation with xylose alone also increased the synthesis of the polyamine spermidine and its precursor S-adenosylmethionine. Thus, differences in carbon substrates, including glucose and xylose in the fermentation medium, strongly influenced the dynamic metabolism of MA-R4

Clinical utility of polymorphisms in one-carbon metabolism for breast cancer risk prediction

Directory of Open Access Journals (Sweden)

Shaik Mohammad Naushad

2011-01-01

Full Text Available This study addresses the issues in translating the laboratory derived data obtained during discovery phase of research to a clinical setting using a breast cancer model. Laboratory-based risk assessment indi-cated that a family history of breast cancer, reduced folate carrier 1 (RFC1 G80A, thymidylate synthase (TYMS 5’-UTR 28bp tandem repeat, methylene tetrahydrofolate reductase (MTHFR C677T and catecholamine-O-methyl transferase (COMT genetic polymorphisms in one-carbon metabolic pathway increase the risk for breast cancer. Glutamate carboxypeptidase II (GCPII C1561T and cytosolic serine hydroxymethyl transferase (cSHMT C1420T polymorphisms were found to decrease breast cancer risk. In order to test the clinical validity of this information in the risk prediction of breast cancer, data was stratified based on number of protective alleles into four categories and in each category sensitivity and 1-specificity values were obtained based on the distribution of number of risk alleles in cases and controls. Receiver operating characteristic (ROC curves were plotted and the area under ROC curve (C was used as a measure of discriminatory ability between cases and controls. In subjects without any protective allele, aberrations in one-carbon metabolism showed perfect prediction (C=0.93 while the predictability was lost in subjects with one protective allele (C=0.60. However, predictability increased steadily with increasing number of protective alleles (C=0.63 for 2 protective alleles and C=0.71 for 3 protective alleles. The cut-off point for discrimination was >4 alleles in all predictable combinations. Models of this kind can serve as valuable tools in translational re-search, especially in identifying high-risk individuals and reducing the disease risk either by life style modification or by medical intervention.

Ameliorating mitochondrial dysfunction restores carbon ion-induced cognitive deficits via co-activation of NRF2 and PINK1 signaling pathway

Directory of Open Access Journals (Sweden)

Yang Liu

2018-07-01

Full Text Available Carbon ion therapy is a promising modality in radiotherapy to treat tumors, however, a potential risk of induction of late normal tissue damage should still be investigated and protected. The aim of the present study was to explore the long-term cognitive deficits provoked by a high-linear energy transfer (high-LET carbon ions in mice by targeting to hippocampus which plays a crucial role in memory and learning. Our data showed that, one month after 4 Gy carbon ion exposure, carbon ion irradiation conspicuously resulted in the impaired cognitive performance, neurodegeneration and neuronal cell death, as well as the reduced mitochondrial integrity, the disrupted activities of tricarboxylic acid cycle flux and electron transport chain, and the depressed antioxidant defense system, consequently leading to a decline of ATP production and persistent oxidative damage in the hippocampus region. Mechanistically, we demonstrated the disruptions of mitochondrial homeostasis and redox balance typically characterized by the disordered mitochondrial dynamics, mitophagy and glutathione redox couple, which is closely associated with the inhibitions of PINK1 and NRF2 signaling pathway as the key regulators of molecular responses in the context of neurotoxicity and neurodegenerative disorders. Most importantly, we found that administration with melatonin as a mitochondria-targeted antioxidant promoted the PINK1 accumulation on the mitochondrial membrane, and augmented the NRF2 accumulation and translocation. Moreover, melatonin pronouncedly enhanced the molecular interplay between NRF2 and PINK1. Furthermore, in the mouse hippocampal neuronal cells, overexpression of NRF2/PINK1 strikingly protected the hippocampal neurons from carbon ion-elicited toxic insults. Thus, these data suggest that alleviation of the sustained mitochondrial dysfunction and oxidative stress through co-modulation of NRF2 and PINK1 may be in charge of restoration of the cognitive

Dilution limits dissolved organic carbon utilization in the deep ocean

NARCIS (Netherlands)

Arrieta, J.M.; Mayol, E.; Hansman, R.L.; Herndl, G.J.; Dittmar, T.; Duarte, C.M.

2015-01-01

Oceanic dissolved organic carbon (DOC) is the second largest reservoir of organic carbon in the biosphere. About 72% of the global DOC inventory is stored in deep oceanic layers for years to centuries, supporting the current view that it consists of materials resistant to microbial degradation. An

Utilization of xylose as a carbon source for mixotrophic growth of Scenedesmus obliquus.

Science.gov (United States)

Yang, Suling; Liu, Guijun; Meng, Youting; Wang, Ping; Zhou, Sijing; Shang, Hongzhong

2014-11-01

Mixotrophic cultivation is one potential mode for microalgae production, and an economically acceptable and environmentally sustainable organic carbon source is essential. The potential use of xylose for culturing Scenedesmus obliquus in a mixotrophic mode and physiological features of xylose-grown S. obliquus were studied. S. obliquus had a certain xylose tolerance, and was capable of utilizing xylose for growth. At a xylose concentration of 4gL(-1), the maximal cell density was 2.2gL(-1), being 2.9-fold of that under photoautotrophic condition and arriving to the level of mixotrophic growth using 4gL(-1) glucose. No changes in cellular morphology of the cells grown with or without xylose were detected. Fluorescence emission from photosystem II (PS II) relative to photosystem I (PS I) was decreased in mixotrophic cells, implying that the PSII activity was decreased. The biomass lipid content was enhanced and carbohydrate concentration was decreased, in relation to photoautotrophic controls. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mainstreaming Low-Carbon Climate-Resilient growth pathways into investment decision-making - lessons from development financial institutions on approaches and tools

International Nuclear Information System (INIS)

Cochran, Ian; Eschalier, Claire; Deheza, Mariana

2015-01-01

The integration or 'mainstreaming' of the transition to a low-carbon climate-resilient future as a prism through which to make financial decisions poses a broad number of operational challenges. This background paper for the March 31 event is drawn from the report currently underway by CDC Climat Research supported by the Group Agence Francaise de Developpement and the Group Caisse des depots entitled 'Mainstreaming Low-Carbon Climate-Resilient Growth Pathways into International Finance Institutions' Activities: Identifying standards and tools and a typology for integration into operational decision-making'. Drawing from existing studies of current practice among mainly public development finance institutions (DFIs), this paper presents three families of tools and metrics used by DFIs to integrate climate change into investment decision-making. It presents a number of examples of how institutions have mainstreamed these issues into upstream strategic and downstream assessment processes. This paper also identifies the further challenge of moving from a system of tools and indicators that focus principally on climate finance tracking - important to foster trust and progress on international cooperation - to a means of aligning activities across financial institutions and the entire economy with the transition to a low-carbon climate-resilient economic model necessary to achieve the 2 deg. C commitment. (authors)

Underground coal gasification with extended CO2 utilization as economic and carbon neutral approach to address energy and fertilizer supply shortages in Bangladesh

Science.gov (United States)

Nakaten, Natalie; Islam, Rafiqul; Kempka, Thomas

2014-05-01

The application of underground coal gasification (UCG) with proven carbon mitigation techniques may provide a carbon neutral approach to tackle electricity and fertilizer supply shortages in Bangladesh. UCG facilitates the utilization of deep-seated coal seams, not economically exploitable by conventional coal mining. The high-calorific synthesis gas produced by UCG can be used for e.g. electricity generation or as chemical raw material for hydrogen, methanol and fertilizer production. Kempka et al. (2010) carried out an integrated assessment of UCG operation, demonstrating that about 19 % of the CO2 produced during UCG may be mitigated by CO2 utilization in fertilizer production. In the present study, we investigated an extension of the UCG system by introducing excess CO2 storage in the gas deposit of the Bahkrabad gas field (40 km east of Dhaka, Bangladesh). This gas field still holds natural gas resources of 12.8 million tons of LNG equivalent, but is close to abandonment due to a low reservoir pressure. Consequently, applying enhanced gas recovery (EGR) by injection of excess carbon dioxide from the coupled UCG-urea process may mitigate carbon emissions and support natural gas production from the Bahkrabad gas field. To carry out an integrated techno-economic assessment of the coupled system, we adapted the techno-economic UCG-CCS model developed by Nakaten et al. (2014) to consider the urea and EGR processes. Reservoir simulations addressing EGR in the Bakhrabad gas field by utilization of excess carbon dioxide from the UCG process were carried out to account for the induced pressure increase in the reservoir, and thus additional gas recovery potentials. The Jamalganj coal field in Northwest Bangladesh provides favorable geological and infrastructural conditions for a UCG operation at coal seam depths of 640 m to 1,158 m. Excess CO2 can be transported via existing pipeline networks to the Bahkrabad gas field (about 300 km distance from the coal deposit) to be

System-based identification of toxicity pathways associated with multi-walled carbon nanotube-induced pathological responses

Energy Technology Data Exchange (ETDEWEB)

Snyder-Talkington, Brandi N. [Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States); Dymacek, Julian [Lane Department of Computer Science and Electrical Engineering, West Virginia University, Morgantown, WV 26506-6070 (United States); Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, WV 26506-9300 (United States); Porter, Dale W.; Wolfarth, Michael G.; Mercer, Robert R. [Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States); Pacurari, Maricica [Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, WV 26506-9300 (United States); Denvir, James [Department of Biochemistry and Microbiology, Marshall University, Huntington, WV 25755 (United States); Castranova, Vincent [Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States); Qian, Yong, E-mail: yaq2@cdc.gov [Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States); Guo, Nancy L., E-mail: lguo@hsc.wvu.edu [Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, WV 26506-9300 (United States)

2013-10-15

The fibrous shape and biopersistence of multi-walled carbon nanotubes (MWCNT) have raised concern over their potential toxicity after pulmonary exposure. As in vivo exposure to MWCNT produced a transient inflammatory and progressive fibrotic response, this study sought to identify significant biological processes associated with lung inflammation and fibrosis pathology data, based upon whole genome mRNA expression, bronchoaveolar lavage scores, and morphometric analysis from C57BL/6J mice exposed by pharyngeal aspiration to 0, 10, 20, 40, or 80 μg MWCNT at 1, 7, 28, or 56 days post-exposure. Using a novel computational model employing non-negative matrix factorization and Monte Carlo Markov Chain simulation, significant biological processes with expression similar to MWCNT-induced lung inflammation and fibrosis pathology data in mice were identified. A subset of genes in these processes was determined to be functionally related to either fibrosis or inflammation by Ingenuity Pathway Analysis and was used to determine potential significant signaling cascades. Two genes determined to be functionally related to inflammation and fibrosis, vascular endothelial growth factor A (vegfa) and C-C motif chemokine 2 (ccl2), were confirmed by in vitro studies of mRNA and protein expression in small airway epithelial cells exposed to MWCNT as concordant with in vivo expression. This study identified that the novel computational model was sufficient to determine biological processes strongly associated with the pathology of lung inflammation and fibrosis and could identify potential toxicity signaling pathways and mechanisms of MWCNT exposure which could be used for future animal studies to support human risk assessment and intervention efforts. - Highlights: • A novel computational model identified toxicity pathways matching in vivo pathology. • Systematic identification of MWCNT-induced biological processes in mouse lungs • MWCNT-induced functional networks of lung

System-based identification of toxicity pathways associated with multi-walled carbon nanotube-induced pathological responses

International Nuclear Information System (INIS)

Snyder-Talkington, Brandi N.; Dymacek, Julian; Porter, Dale W.; Wolfarth, Michael G.; Mercer, Robert R.; Pacurari, Maricica; Denvir, James; Castranova, Vincent; Qian, Yong; Guo, Nancy L.

2013-01-01

The fibrous shape and biopersistence of multi-walled carbon nanotubes (MWCNT) have raised concern over their potential toxicity after pulmonary exposure. As in vivo exposure to MWCNT produced a transient inflammatory and progressive fibrotic response, this study sought to identify significant biological processes associated with lung inflammation and fibrosis pathology data, based upon whole genome mRNA expression, bronchoaveolar lavage scores, and morphometric analysis from C57BL/6J mice exposed by pharyngeal aspiration to 0, 10, 20, 40, or 80 μg MWCNT at 1, 7, 28, or 56 days post-exposure. Using a novel computational model employing non-negative matrix factorization and Monte Carlo Markov Chain simulation, significant biological processes with expression similar to MWCNT-induced lung inflammation and fibrosis pathology data in mice were identified. A subset of genes in these processes was determined to be functionally related to either fibrosis or inflammation by Ingenuity Pathway Analysis and was used to determine potential significant signaling cascades. Two genes determined to be functionally related to inflammation and fibrosis, vascular endothelial growth factor A (vegfa) and C-C motif chemokine 2 (ccl2), were confirmed by in vitro studies of mRNA and protein expression in small airway epithelial cells exposed to MWCNT as concordant with in vivo expression. This study identified that the novel computational model was sufficient to determine biological processes strongly associated with the pathology of lung inflammation and fibrosis and could identify potential toxicity signaling pathways and mechanisms of MWCNT exposure which could be used for future animal studies to support human risk assessment and intervention efforts. - Highlights: • A novel computational model identified toxicity pathways matching in vivo pathology. • Systematic identification of MWCNT-induced biological processes in mouse lungs • MWCNT-induced functional networks of lung

Trading coalbed methane for carbon dioxide

International Nuclear Information System (INIS)

Greenberger, L.S.

1991-01-01

This article discusses a proposal for reducing methane emissions in coal mining activities and at the same time reducing the burden on utilities to cut carbon dioxide emissions. Emission credits would be issued to mines that recover the methane for use. These credits could then be bought by utilities and exchanged for the right to emit carbon dioxide

Short-term utilization of carbon by the soil microbial community under future climatic conditions in a temperate heathland

DEFF Research Database (Denmark)

Reinsch, Sabine; Michelsen, Anders; Sárossy, Zsuzsa

2014-01-01

An in-situ13C pulse-labeling experiment was carried out in a temperate heath/grassland to study the impacts of elevated CO2 concentration (510ppm), prolonged summer droughts (annual exclusion of 7.6±0.8%) and increased temperature (~1°C) on belowground carbon (C) utilization. Recently assimilated C...... (13C from the pulse-label) was traced into roots, soil and microbial biomass 1, 2 and 8 days after pulse-labeling. The importance of the microbial community in C utilization was investigated using 13C enrichment patterns in different microbial functional groups on the basis of phospholipid fatty acid...... (PLFA) biomarker profiles. Climate treatments did not affect microbial abundance in soil or rhizosphere fractions in terms of total PLFA-C concentration. Elevated CO2 significantly reduced the abundance of gram-negative bacteria (17:0cy), but did not affect the abundance of decomposers (fungi...

Inkjet printed ambipolar transistors and inverters based on carbon nanotube/zinc tin oxide heterostructures

International Nuclear Information System (INIS)

Kim, Bongjun; Jang, Seonpil; Dodabalapur, Ananth; Geier, Michael L.; Prabhumirashi, Pradyumna L.; Hersam, Mark C.

2014-01-01

We report ambipolar field-effect transistors (FETs) consisting of inkjet printed semiconductor bilayer heterostructures utilizing semiconducting single-walled carbon nanotubes (SWCNTs) and amorphous zinc tin oxide (ZTO). The bilayer structure allows for electron transport to occur principally in the amorphous oxide layer and hole transport to occur exclusively in the SWCNT layer. This results in balanced electron and hole mobilities exceeding 2 cm 2 V −1 s −1 at low operating voltages ( 10). This work provides a pathway for realizing solution processable, inkjet printable, large area electronic devices, and systems based on SWCNT-amorphous oxide heterostructures

Pathways to Mesoporous Resin/Carbon Thin Films with Alternating Gyroid Morphology

Energy Technology Data Exchange (ETDEWEB)

Zhang, Qi [Department; Matsuoka, Fumiaki [Department; Suh, Hyo Seon [Institute; Materials; Beaucage, Peter A. [Department; Xiong, Shisheng [Institute; Materials; Smilgies, Detlef-M. [Cornell; Tan, Kwan Wee [Department; School; Werner, Jörg G. [Department; Nealey, Paul F. [Institute; Materials; Wiesner, Ulrich B. [Department

2017-12-19

Three-dimensional (3D) mesoporous thin films with sub-100 nm periodic lattices are of increasing interest as templates for a number of nanotechnology applications, yet are hard to achieve with conventional top-down fabrication methods. Block copolymer self-assembly derived mesoscale structures provide a toolbox for such 3D template formation. In this work, single (alternating) gyroidal and double gyroidal mesoporous thin-film structures are achieved via solvent vapor annealing assisted co-assembly of poly(isoprene-block-styrene-block-ethylene oxide) (PI-b-PS-b-PEO, ISO) and resorcinol/phenol formaldehyde resols. In particular, the alternating gyroid thin-film morphology is highly desirable for potential template backfilling processes as a result of the large pore volume fraction. In situ grazing-incidence small-angle X-ray scattering during solvent annealing is employed as a tool to elucidate and navigate the pathway complexity of the structure formation processes. The resulting network structures are resistant to high temperatures provided an inert atmosphere. The thin films have tunable hydrophilicity from pyrolysis at different temperatures, while pore sizes can be tailored by varying ISO molar mass. A transfer technique between substrates is demonstrated for alternating gyroidal mesoporous thin films, circumventing the need to re-optimize film formation protocols for different substrates. Increased conductivity after pyrolysis at high temperatures demonstrates that these gyroidal mesoporous resin/carbon thin films have potential as functional 3D templates for a number of nanomaterials applications.

Rhodococcus erythropolis DCL14 Contains a Novel Degradation Pathway for Limonene

Science.gov (United States)

van der Werf, Mariët J.; Swarts, Henk J.; de Bont, Jan A. M.

1999-01-01

Strain DCL14, which is able to grow on limonene as a sole source of carbon and energy, was isolated from a freshwater sediment sample. This organism was identified as a strain of Rhodococcus erythropolis by chemotaxonomic and genetic studies. R. erythropolis DCL14 also assimilated the terpenes limonene-1,2-epoxide, limonene-1,2-diol, carveol, carvone, and (−)-menthol, while perillyl alcohol was not utilized as a carbon and energy source. Induction tests with cells grown on limonene revealed that the oxygen consumption rates with limonene-1,2-epoxide, limonene-1,2-diol, 1-hydroxy-2-oxolimonene, and carveol were high. Limonene-induced cells of R. erythropolis DCL14 contained the following four novel enzymatic activities involved in the limonene degradation pathway of this microorganism: a flavin adenine dinucleotide- and NADH-dependent limonene 1,2-monooxygenase activity, a cofactor-independent limonene-1,2-epoxide hydrolase activity, a dichlorophenolindophenol-dependent limonene-1,2-diol dehydrogenase activity, and an NADPH-dependent 1-hydroxy-2-oxolimonene 1,2-monooxygenase activity. Product accumulation studies showed that (1S,2S,4R)-limonene-1,2-diol, (1S,4R)-1-hydroxy-2-oxolimonene, and (3R)-3-isopropenyl-6-oxoheptanoate were intermediates in the (4R)-limonene degradation pathway. The opposite enantiomers [(1R,2R,4S)-limonene-1,2-diol, (1R,4S)-1-hydroxy-2-oxolimonene, and (3S)-3-isopropenyl-6-oxoheptanoate] were found in the (4S)-limonene degradation pathway, while accumulation of (1R,2S,4S)-limonene-1,2-diol from (4S)-limonene was also observed. These results show that R. erythropolis DCL14 metabolizes both enantiomers of limonene via a novel degradation pathway that starts with epoxidation at the 1,2 double bond forming limonene-1,2-epoxide. This epoxide is subsequently converted to limonene-1,2-diol, 1-hydroxy-2-oxolimonene, and 7-hydroxy-4-isopropenyl-7-methyl-2-oxo-oxepanone. This lactone spontaneously rearranges to form 3-isopropenyl-6-oxoheptanoate. In

Carbon Source-Dependent Inducible Metabolism of Veratryl Alcohol and Ferulic Acid in Pseudomonas putida CSV86

Science.gov (United States)

Mohan, Karishma

2017-01-01

ABSTRACT Pseudomonas putida CSV86 degrades lignin-derived metabolic intermediates, viz., veratryl alcohol, ferulic acid, vanillin, and vanillic acid, as the sole sources of carbon and energy. Strain CSV86 also degraded lignin sulfonate. Cell respiration, enzyme activity, biotransformation, and high-pressure liquid chromatography (HPLC) analyses suggest that veratryl alcohol and ferulic acid are metabolized to vanillic acid by two distinct carbon source-dependent inducible pathways. Vanillic acid was further metabolized to protocatechuic acid and entered the central carbon pathway via the β-ketoadipate route after ortho ring cleavage. Genes encoding putative enzymes involved in the degradation were found to be present at fer, ver, and van loci. The transcriptional analysis suggests a carbon source-dependent cotranscription of these loci, substantiating the metabolic studies. Biochemical and quantitative real-time (qRT)-PCR studies revealed the presence of two distinct O-demethylases, viz., VerAB and VanAB, involved in the oxidative demethylation of veratric acid and vanillic acid, respectively. This report describes the various steps involved in metabolizing lignin-derived aromatic compounds at the biochemical level and identifies the genes involved in degrading veratric acid and the arrangement of phenylpropanoid metabolic genes as three distinct inducible transcription units/operons. This study provides insight into the bacterial degradation of lignin-derived aromatics and the potential of P. putida CSV86 as a suitable candidate for producing valuable products. IMPORTANCE Pseudomonas putida CSV86 metabolizes lignin and its metabolic intermediates as a carbon source. Strain CSV86 displays a unique property of preferential utilization of aromatics, including for phenylpropanoids over glucose. This report unravels veratryl alcohol metabolism and genes encoding veratric acid O-demethylase, hitherto unknown in pseudomonads, thereby providing new insight into the

Achievement report of projects in fiscal 2000 for measures on technologies to fix and utilize effectively carbon dioxide. Development of program system technologies to fix and utilize effectively carbon dioxide - researches on key technologies (Developing technology to fix carbon dioxide electrochemically); 2000 nendo program hoshiki nisanka tanso koteika yuko riyo gijutsu kaihatsu (kiban gijutsu kenkyu) seika hokokusho (kokaiyo). Nisanka tanso no denki kagakuteki koteika gijutsu no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

With an objective to prevent global warming, research and development has been made on a carbon dioxide fixation technology using electrochemical means. This paper summarizes the achievements in fiscal 2000. In the research of a technology to return carbon dioxide to hydrocarbon such as methane electrochemically utilizing the high concentration carbon dioxide-methanol system, basic studies were performed on electrolytic reduction of CO2 using a methanol solvent system, and experimental studies were executed on high-speed reduction of carbon dioxide using gas diffusion electrodes. In the basic property experiment on diamond electrodes, high carbon dioxide reduction activity was obtained by having copper carried in the diamond electrode. In the CO2 electrolytic reduction experiment on three-phase interface using a copper net electrode, CO, ethylene, and methane were produced, while the electrode has retained the activity for an extended period of time, and the CO2 conversion rate reached about 66%. In structuring an electrochemical carbon dioxide fixation system, specifications for the CO2 electrolytic reduction equipment were determined, design, manufacturing, and electrode materials were selected, supporting electrolytes were discussed, and the entire system flow and liquid resistance were discussed. (NEDO)

Beneficial Use of Carbon Dioxide in Precast Concrete Production

Energy Technology Data Exchange (ETDEWEB)

Shao, Yixin [McGill Univ., Montreal, QC (Canada)

2014-06-26

The feasibility of using carbon dioxide as feedstock in precast concrete production is studied. Carbon dioxide reacts with calcium compounds in concrete, producing solid calcium carbonates in binding matrix. Two typical precast products are examined for their capacity to store carbon dioxide during the production. They are concrete blocks and fiber-cement panels. The two products are currently mass produced and cured by steam. Carbon dioxide can be used to replace steam in curing process to accelerate early strength, improve the long-term durability and reduce energy and emission. For a reaction within a 24-hour process window, the theoretical maximum possible carbon uptake in concrete is found to be 29% based on cement mass in the product. To reach the maximum uptake, a special process is developed to promote the reaction efficiency to 60-80% in 4-hour carbon dioxide curing and improve the resistance to freeze-thaw cycling and sulfate ion attack. The process is also optimized to meet the project target of $10/tCO₂ in carbon utilization. By the use of self-concentrating absorption technology, high purity CO₂ can be produced at a price below $40/t. With low cost CO₂ capture and utilization technologies, it is feasible to establish a network for carbon capture and utilization at the vicinity of carbon sources. If all block produces and panel producers in United States could adopt carbon dioxide process in their production in place of steam, carbon utilization in these two markets alone could consume more than 2 Mt CO₂/year. This capture and utilization process can be extended to more precast products and will continue for years to come.

The air quality and health co-benefits of alternative post-2020 pathways for achieving peak carbon targets in Jiangsu, China

Science.gov (United States)

Liu, M.; Bi, J.; Huang, Y.; Kinney, P. L.

2016-12-01

Jiangsu, which has three national low-carbon pilot cities, is set to be a model province in China for achieving peak carbon targets before 2030. However, according to local planning of responding to climate change, carbon emissions are projected to keep going up before 2020 even the strictest measures are implemented. In other words, innovative measures must be in action after 2020. This work aimed at assessing the air quality and health co-benefits of alternative post-2020 measures to help remove barriers of policy implementation through tying it to local incentives for air quality improvement. To achieve the aim, we select 2010 as baseline year and develop Bussiness As Usual (BAU) and Traditional Carbon Reduction (TCR) scenarios before 2020. Under BAU, only existing climate and air pollution control policies are considered; under TCR, potential climate policies in local planning and existing air pollution control policies are considered. After 2020, integrated gasification combined cycle (IGCC) plant with carbon capture and storage (CCS) technology and large-scale substitution of renewable energy seem to be two promising pathways for achieving peak carbon targets. Therefore, two additional scenarios (TCR-IGCC and TCR-SRE) are set after 2020. Based on the projections of future energy balances and industrial productions, we estimate the pollutant emissions and simulate PM2.5 and ozone concentrations by 2017, 2020, 2030 and 2050 using CMAQ. Then using health impact assessment approach, the premature deaths are estimated and monetized. Results show that the carbon peak in Jiangsu will be achieved before 2030 only under TCR-IGCC and TCR-SRE scenarios. Under three policy scenarios, Jiangsu's carbon emission control targets would have substantial effects on primary air pollutant emissions far beyond those we estimate would be needed to meet the PM2.5 concentration targets in 2017. Compared with IGCC with CCS, large-scale substitutions of renewable energy bring

Utilization of biodiesel by-product as substrate for high-production of β-farnesene via relatively balanced mevalonate pathway in Escherichia coli.

Science.gov (United States)

You, Shengping; Yin, Qingdian; Zhang, Jianye; Zhang, Chengyu; Qi, Wei; Gao, Lan; Tao, Zhiping; Su, Rongxin; He, Zhimin

2017-11-01

Farnesene has been identified as suitable jet fuel substitutes and metabolic engineering for microbial production of farnesene is an alternative and attractive route. In this study, due to accumulation of toxic intermediate isopentenyl pyrophosphate (IPP), an engineered Escherichia coli strain harboring heterologous mevalonate pathway produced only 4.11mg/L β-farnesene. Through higher-level expression of isopentenyl diphosphate isomerase and farnesyl diphosphate synthase to minimize the accumulated IPP, another engineered strain with relatively balanced mevalonate pathway was constructed and had the highest production of β-farnesene to date (8.74g/L) by Escherichia coli in a lab bioreactor. Furthermore, this is the first report on utilization of biodiesel by-product (simple purification) as substrate for high-production of β-farnesene by the engineered strain optimized and β-farnesene concentration reached 2.83g/L in a lab bioreactor. Therefore, the engineered strain optimized could be used as a platform host for high-production of other terpenoids using biodiesel by-product as substrate. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pathways to deep decarbonization in India

DEFF Research Database (Denmark)

Shukla, P.; Dhar, Subash; Pathak, Minal

This report is a part of the global Deep Decarbonisation Pathways (DDP) Project. The analysis consider two development scenarios for India and assess alternate roadmaps for transiting to a low carbon economy consistent with the globally agreed 2°C stabilization target. The report does not conside...

UTILIZATION OF LOW NOx COAL COMBUSTION BY-PRODUCTS

Energy Technology Data Exchange (ETDEWEB)

J.Y. Hwang; X. Huang; M.G. McKimpson; R.E. Tieder; A.M. Hein; J.M. Gillis; D.C. Popko; K.L. Paxton; Z. Li; X. Liu; X. Song; R.I. Kramer

1998-12-01

Low NO{sub x} combustion practices are critical for reducing NO{sub x} emissions from power plants. These low NO{sub x} combustion practices, however, generate high residual carbon contents in the fly ash produced. These high carbon contents threaten utilization of this combustion by-product. This research has successfully developed a separation technology to render fly ash into useful, quality-controlled materials. This technology offers great flexibility and has been shown to be applicable to all of the fly ashes tested (more than 10). The separated materials can be utilized in traditional fly ash applications, such as cement and concrete, as well as in nontraditional applications such as plastic fillers, metal matrix composites, refractories, and carbon adsorbents. Technologies to use beneficiated fly ash in these applications are being successfully developed. In the future, we will continue to refine the separation and utilization technologies to expand the utilization of fly ash. The disposal of more than 31 million tons of fly ash per year is an important environmental issue. With continued development, it will be possible to increase economic, energy and environmental benefits by re-directing more of this fly ash into useful materials.

Radiation damage in carbon-carbon composites

International Nuclear Information System (INIS)

Burchell, T.D.; Eartherly, W.P.; Nelson, G.E.

1992-01-01

Graphite and carbon-carbon composite materials are widely used in plasma facing applications in current Tokamak devices such as TFTR and DIIID in the USA, JET, Tore Supra and TEXTOR in Europe, and JT-60U in Japan. Carbon-carbon composites are attractive choices for Tokamak limiters and diverters because of their low atomic number, high thermal shock resistance, high melting point, and high thermal conductivity. Next generation machines such as the International Thermonuclear Experimental Reactor (ITER) will utilize carbon-carbon composites in their first wall and diverter. ITER will be an ignition machine and thus will produce substantial neutron fluences from the D-T fusion reaction. The resultant high energy neutrons will cause carbon atom displacements in the plasma facing materials which will markedly affect their structure and physical properties. The effect of neutron damage on graphite has been studied for over forty years. Recently the effects of neutron irradiation on the fusion relevant graphite GraphNOL N3M was reviewed. In contrast to graphite, relatively little work has been performed to elucidate the effects of neutron irradiation on carbon-carbon composites. The results of our previous irradiation experiments have been published elsewhere. Here the irradiation induced dimensional changes in 1D, 2D, and 3D carbon-carbon composites are reported for fluences up to 4.7 dpa at an irradiation temperature of 600 degree C

Current and Future United States Light-Duty Vehicle Pathways: Cradle-to-Grave Lifecycle Greenhouse Gas Emissions and Economic Assessment.

Science.gov (United States)

Elgowainy, Amgad; Han, Jeongwoo; Ward, Jacob; Joseck, Fred; Gohlke, David; Lindauer, Alicia; Ramsden, Todd; Biddy, Mary; Alexander, Mark; Barnhart, Steven; Sutherland, Ian; Verduzco, Laura; Wallington, Timothy J

2018-02-20

This article presents a cradle-to-grave (C2G) assessment of greenhouse gas (GHG) emissions and costs for current (2015) and future (2025-2030) light-duty vehicles. The analysis addressed both fuel cycle and vehicle manufacturing cycle for the following vehicle types: gasoline and diesel internal combustion engine vehicles (ICEVs), flex fuel vehicles, compressed natural gas (CNG) vehicles, hybrid electric vehicles (HEVs), hydrogen fuel cell electric vehicles (FCEVs), battery electric vehicles (BEVs), and plug-in hybrid electric vehicles (PHEVs). Gasoline ICEVs using current technology have C2G emissions of ∼450 gCO 2 e/mi (grams of carbon dioxide equivalents per mile), while C2G emissions from HEVs, PHEVs, H 2 FCEVs, and BEVs range from 300-350 gCO 2 e/mi. Future vehicle efficiency gains are expected to reduce emissions to ∼350 gCO 2 /mi for ICEVs and ∼250 gCO 2e /mi for HEVs, PHEVs, FCEVs, and BEVs. Utilizing low-carbon fuel pathways yields GHG reductions more than double those achieved by vehicle efficiency gains alone. Levelized costs of driving (LCDs) are in the range $0.25-$1.00/mi depending on time frame and vehicle-fuel technology. In all cases, vehicle cost represents the major (60-90%) contribution to LCDs. Currently, HEV and PHEV petroleum-fueled vehicles provide the most attractive cost in terms of avoided carbon emissions, although they offer lower potential GHG reductions. The ranges of LCD and cost of avoided carbon are narrower for the future technology pathways, reflecting the expected economic competitiveness of these alternative vehicles and fuels.

Current and Future United States Light-Duty Vehicle Pathways: Cradle-to-Grave Lifecycle Greenhouse Gas Emissions and Economic Assessment

Energy Technology Data Exchange (ETDEWEB)

Elgowainy, Amgad [Argonne National Laboratory, Argonne, Illinois 60439, United States; Han, Jeongwoo [Argonne National Laboratory, Argonne, Illinois 60439, United States; Ward, Jacob [United States Department of Energy, Washington, D.C. 20585, United States; Joseck, Fred [United States Department of Energy, Washington, D.C. 20585, United States; Gohlke, David [Argonne National Laboratory, Argonne, Illinois 60439, United States; Lindauer, Alicia [United States Department of Energy, Washington, D.C. 20585, United States; Ramsden, Todd [National Renewable Energy Laboratory, Golden, Colorado 80401, United States; Biddy, Mary [National Renewable Energy Laboratory, Golden, Colorado 80401, United States; Alexander, Mark [Electric Power Research Institute, Palo; Barnhart, Steven [FCA US LLC, Auburn Hills, Michigan 48326, United States; Sutherland, Ian [General Motors, Pontiac, Michigan 48340, United States; Verduzco, Laura [Chevron Corporation, Richmond, California 94802, United States; Wallington, Timothy J. [Ford Motor Company, Dearborn, Michigan 48121, United States

2018-01-30

This article presents a cradle-to-grave (C2G) assessment of greenhouse gas (GHG) emissions and costs for current (2015) and future (2025–2030) light-duty vehicles. The analysis addressed both fuel cycle and vehicle manufacturing cycle for the following vehicle types: gasoline and diesel internal combustion engine vehicles (ICEVs), flex fuel vehicles, compressed natural gas (CNG) vehicles, hybrid electric vehicles (HEVs), hydrogen fuel cell electric vehicles (FCEVs), battery electric vehicles (BEVs), and plug-in hybrid electric vehicles (PHEVs). Gasoline ICEVs using current technology have C2G emissions of ~450 gCO2e/mi (grams of carbon dioxide equivalents per mile), while C2G emissions from HEVs, PHEVs, H2 FCEVs, and BEVs range from 300–350 gCO2e/mi. Future vehicle efficiency gains are expected to reduce emissions to ~350 gCO2/mi for ICEVs and ~250 gCO2e/mi for HEVs, PHEVs, FCEVs and BEVs. Utilizing low-carbon fuel pathways yields GHG reductions more than double those achieved by vehicle efficiency gains alone. Levelized costs of driving (LCDs) are in the range $0.25–$1.00/mi depending on timeframe and vehicle-fuel technology. In all cases, vehicle cost represents the major (60–90%) contribution to LCDs. Currently, HEV and PHEV petroleum-fueled vehicles provide the most attractive cost in terms of avoided carbon emissions, although they offer lower potential GHG reductions The ranges of LCD and cost of avoided carbon are narrower for the future technology pathways, reflecting the expected economic competitiveness of these alternative vehicles and fuels.

Pathways of carbon and energy metabolism of the epibiotic community associated with the deep-sea hydrothermal vent shrimp Rimicaris exoculata.

Science.gov (United States)

Hügler, Michael; Petersen, Jillian M; Dubilier, Nicole; Imhoff, Johannes F; Sievert, Stefan M

2011-01-07

The shrimp Rimicaris exoculata dominates the faunal biomass at many deep-sea hydrothermal vent sites at the Mid-Atlantic Ridge. In its enlarged gill chamber it harbors a specialized epibiotic bacterial community for which a nutritional role has been proposed. We analyzed specimens from the Snake Pit hydrothermal vent field on the Mid-Atlantic Ridge by complementing a 16S rRNA gene survey with the analysis of genes involved in carbon, sulfur and hydrogen metabolism. In addition to Epsilon- and Gammaproteobacteria, the epibiotic community unexpectedly also consists of Deltaproteobacteria of a single phylotype, closely related to the genus Desulfocapsa. The association of these phylogenetic groups with the shrimp was confirmed by fluorescence in situ hybridization. Based on functional gene analyses, we hypothesize that the Gamma- and Epsilonproteobacteria are capable of autotrophic growth by oxidizing reduced sulfur compounds, and that the Deltaproteobacteria are also involved in sulfur metabolism. In addition, the detection of proteobacterial hydrogenases indicates the potential for hydrogen oxidation in these communities. Interestingly, the frequency of these phylotypes in 16S rRNA gene clone libraries from the mouthparts differ from that of the inner lining of the gill chamber, indicating potential functional compartmentalization. Our data show the specific association of autotrophic bacteria with Rimicaris exoculata from the Snake Pit hydrothermal vent field, and suggest that autotrophic carbon fixation is contributing to the productivity of the epibiotic community with the reductive tricarboxylic acid cycle as one important carbon fixation pathway. This has not been considered in previous studies of carbon fixation and stable carbon isotope composition of the shrimp and its epibionts. Furthermore, the co-occurrence of sulfur-oxidizing and sulfur-reducing epibionts raises the possibility that both may be involved in the syntrophic exchange of sulfur compounds

North and south: Regional footprints on the transition pathway towards a low carbon, global economy

International Nuclear Information System (INIS)

Cranston, G.R.; Hammond, G.P.

2010-01-01

Environmental or 'ecological' footprints are indicators of resource consumption and waste absorption transformed on the basis of biologically productive land area required per capita with prevailing technology. They represent a partial measure of the extent to which the planet, its regions, or nations are moving along a sustainable development pathway. Such footprints vary between countries at different stages of economic development and varying geographic characteristics. A correlation equation for national environmental footprints is used, alongside international projections of population growth and gross regional income, to estimate the relative contributions of the peoples of the industrialised North and populous South that would be needed in order to secure climate-stabilising carbon reductions out to about 2100. The four so-called 'marker scenarios' produced by the Intergovernmental Panel on Climate Change are used to estimate the degree of energy efficiency improvement and carbon mitigation that is feasible. The present footprint projections suggest that a reduction in the consumption of biophysical assets across both the developing and industrialised world is indeed possible. However, the developing world's footprint is shown to overshoot that of the industrialised countries by around 2010-2015. It then levels out and starts to fall, on the most optimistic scenario, by about 2050. In order to achieve global sustainability in the 21st Century a serious commitment to environmental protection is required in both the industrialised North and the 'majority South'. That implies balancing population growth, economic well-being, and environmental impacts in the interests of all the people and wildlife on 'Spaceship Earth'.

Carbon dioxide sequestration by direct mineral carbonation with carbonic acid

Energy Technology Data Exchange (ETDEWEB)

O' Connor, William K.; Dahlin, David C.; Nilsen, David N.; Walters, Richard P.; Turner, Paul C.

2000-01-01

The Albany Research Center (ARC) of the U.S. Dept. of Energy (DOE) has been conducting a series of mineral carbonation tests at its Albany, Oregon, facility over the past 2 years as part of a Mineral Carbonation Study Program within the DOE. Other participants in this Program include the Los Alamos National Laboratory, Arizona State University, Science Applications International Corporation, and the DOE National Energy Technology Laboratory. The ARC tests have focused on ex-situ mineral carbonation in an aqueous system. The process developed at ARC utilizes a slurry of water mixed with a magnesium silicate mineral, olivine [forsterite end member (Mg2SiO4)], or serpentine [Mg3Si2O5(OH)4]. This slurry is reacted with supercritical carbon dioxide (CO2) to produce magnesite (MgCO3). The CO2 is dissolved in water to form carbonic acid (H2CO3), which dissociates to H+ and HCO3 -. The H+ reacts with the mineral, liberating Mg2+ cations which react with the bicarbonate to form the solid carbonate. The process is designed to simulate the natural serpentinization reaction of ultramafic minerals, and for this reason, these results may also be applicable to in-situ geological sequestration regimes. Results of the baseline tests, conducted on ground products of the natural minerals, have been encouraging. Tests conducted at ambient temperature (22 C) and subcritical CO2 pressures (below 73 atm) resulted in very slow conversion to the carbonate. However, when elevated temperatures and pressures are utilized, coupled with continuous stirring of the slurry and gas dispersion within the water column, significant reaction occurs within much shorter reaction times. Extent of reaction, as measured by the stoichiometric conversion of the silicate mineral (olivine) to the carbonate, is roughly 90% within 24 hours, using distilled water, and a reaction temperature of 185?C and a partial pressure of CO2 (PCO2) of 115 atm. Recent tests using a bicarbonate solution, under identical reaction

Carbon dioxide sequestration by direct mineral carbonation with carbonic acid

Energy Technology Data Exchange (ETDEWEB)

O' Connor, W.K.; Dahlin, D.C.; Nilsen, D.N.; Walters, R.P.; Turner, P.C.

2000-07-01

The Albany Research Center (ARC) of the US Department of Energy (DOE) has been conducting a series of mineral carbonation tests at its Albany, Oregon, facility over the past 2 years as part of a Mineral Carbonation Study Program within the DOE. The ARC tests have focused on ex-situ mineral carbonation in an aqueous system. The process developed at ARC utilizes a slurry of water mixed with a magnesium silicate mineral, olivine [forsterite and member (mg{sub 2}SiO{sub 4})], or serpentine [Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 4}]. This slurry is reacted with supercritical carbon dioxide (CO{sub 2}) to produce magnesite (MgCO{sub 3}). The CO{sub 2} is dissolved in water to form carbonic acid (H{sub 2}CO{sub 3}), which dissociates to H{sup +} and HCO{sub 3}{sup {minus}}. The H{sup +} reacts with the mineral, liberating Mg{sup 2+} cations which react with the bicarbonate to form the solid carbonate. The process is designed to simulate the natural serpentinization reaction of ultramafic minerals, and for this reason, these results may also be applicable to in-situ geological sequestration regimes. Results of the baseline tests, conducted on ground products of the natural minerals, have been encouraging. Tests conducted at ambient temperature (22 C) and subcritical CO{sub 2} pressures (below 73 atm) resulted in very slow conversion to the carbonate. However, when elevated temperatures and pressures are utilized, coupled with continuous stirring of the slurry and gas dispersion within the water column, significant reaction occurs within much shorter reaction times. Extent of reaction, as measured by the stoichiometric conversion of the silicate mineral (olivine) to the carbonate, is roughly 90% within 24 hours, using distilled water, and a reaction temperature of 185 C and a partial pressure of CO{sub 2} (P{sub CO{sub 2}}) of 115 atm. Recent tests using a bicarbonate solution, under identical reaction conditions, have achieved roughly 83% conversion of heat treated serpentine

Ameliorating mitochondrial dysfunction restores carbon ion-induced cognitive deficits via co-activation of NRF2 and PINK1 signaling pathway.

Science.gov (United States)

Liu, Yang; Yan, Jiawei; Sun, Cao; Li, Guo; Li, Sirui; Zhang, Luwei; Di, Cuixia; Gan, Lu; Wang, Yupei; Zhou, Rong; Si, Jing; Zhang, Hong

2018-07-01

Carbon ion therapy is a promising modality in radiotherapy to treat tumors, however, a potential risk of induction of late normal tissue damage should still be investigated and protected. The aim of the present study was to explore the long-term cognitive deficits provoked by a high-linear energy transfer (high-LET) carbon ions in mice by targeting to hippocampus which plays a crucial role in memory and learning. Our data showed that, one month after 4 Gy carbon ion exposure, carbon ion irradiation conspicuously resulted in the impaired cognitive performance, neurodegeneration and neuronal cell death, as well as the reduced mitochondrial integrity, the disrupted activities of tricarboxylic acid cycle flux and electron transport chain, and the depressed antioxidant defense system, consequently leading to a decline of ATP production and persistent oxidative damage in the hippocampus region. Mechanistically, we demonstrated the disruptions of mitochondrial homeostasis and redox balance typically characterized by the disordered mitochondrial dynamics, mitophagy and glutathione redox couple, which is closely associated with the inhibitions of PINK1 and NRF2 signaling pathway as the key regulators of molecular responses in the context of neurotoxicity and neurodegenerative disorders. Most importantly, we found that administration with melatonin as a mitochondria-targeted antioxidant promoted the PINK1 accumulation on the mitochondrial membrane, and augmented the NRF2 accumulation and translocation. Moreover, melatonin pronouncedly enhanced the molecular interplay between NRF2 and PINK1. Furthermore, in the mouse hippocampal neuronal cells, overexpression of NRF2/PINK1 strikingly protected the hippocampal neurons from carbon ion-elicited toxic insults. Thus, these data suggest that alleviation of the sustained mitochondrial dysfunction and oxidative stress through co-modulation of NRF2 and PINK1 may be in charge of restoration of the cognitive impairments in a mouse

One carbon metabolism in SAR11 pelagic marine bacteria.

Directory of Open Access Journals (Sweden)

Jing Sun

Full Text Available The SAR11 Alphaproteobacteria are the most abundant heterotrophs in the oceans and are believed to play a major role in mineralizing marine dissolved organic carbon. Their genomes are among the smallest known for free-living heterotrophic cells, raising questions about how they successfully utilize complex organic matter with a limited metabolic repertoire. Here we show that conserved genes in SAR11 subgroup Ia (Candidatus Pelagibacter ubique genomes encode pathways for the oxidation of a variety of one-carbon compounds and methyl functional groups from methylated compounds. These pathways were predicted to produce energy by tetrahydrofolate (THF-mediated oxidation, but not to support the net assimilation of biomass from C1 compounds. Measurements of cellular ATP content and the oxidation of (14C-labeled compounds to (14CO(2 indicated that methanol, formaldehyde, methylamine, and methyl groups from glycine betaine (GBT, trimethylamine (TMA, trimethylamine N-oxide (TMAO, and dimethylsulfoniopropionate (DMSP were oxidized by axenic cultures of the SAR11 strain Ca. P. ubique HTCC1062. Analyses of metagenomic data showed that genes for C1 metabolism occur at a high frequency in natural SAR11 populations. In short term incubations, natural communities of Sargasso Sea microbial plankton expressed a potential for the oxidation of (14C-labeled formate, formaldehyde, methanol and TMAO that was similar to cultured SAR11 cells and, like cultured SAR11 cells, incorporated a much larger percentage of pyruvate and glucose (27-35% than of C1 compounds (2-6% into biomass. Collectively, these genomic, cellular and environmental data show a surprising capacity for demethylation and C1 oxidation in SAR11 cultures and in natural microbial communities dominated by SAR11, and support the conclusion that C1 oxidation might be a significant conduit by which dissolved organic carbon is recycled to CO(2 in the upper ocean.

Ecological carbon sequestration via wood harvest and storage (WHS): Can it be a viable climate mitigation and adaptation strategy for the Amazon?

Science.gov (United States)

Zeng, N.

2015-12-01

A carbon sequestration strategy is proposed in which forests are sustainably managed to optimal carbon productivity, and a fraction of the wood is selectively harvested and stored to prevent decomposition under anaerobic, dry or cold conditions. Because a large flux of CO2 is constantly assimilated into the world's forests via photosynthesis, cutting off its return pathway to the atmosphere forms an effective carbon sink. The live trees serve as a 'carbon scrubber' or 'carbon remover' that provides continuous sequestration (negative emissions). The stored wood is a semi-permanent carbon sink, but also serves as a 'biomass/bioenergy reserve' that could be utilized in the future. We discuss the particular relevance of this strategy to the Amazon which is under the double threat of climate change and deforestation. As an alternative to REDD, we propose mixed-use of peripheral Amazon basin while keeping the core of the Amazon intact. We argue that this may be a more practical solution in light of the likely climate change impact and human activities.

Assessment of self-organizing maps to analyze sole-carbon source utilization profiles.

Science.gov (United States)

Leflaive, Joséphine; Céréghino, Régis; Danger, Michaël; Lacroix, Gérard; Ten-Hage, Loïc

2005-07-01

The use of community-level physiological profiles obtained with Biolog microplates is widely employed to consider the functional diversity of bacterial communities. Biolog produces a great amount of data which analysis has been the subject of many studies. In most cases, after some transformations, these data were investigated with classical multivariate analyses. Here we provided an alternative to this method, that is the use of an artificial intelligence technique, the Self-Organizing Maps (SOM, unsupervised neural network). We used data from a microcosm study of algae-associated bacterial communities placed in various nutritive conditions. Analyses were carried out on the net absorbances at two incubation times for each substrates and on the chemical guild categorization of the total bacterial activity. Compared to Principal Components Analysis and cluster analysis, SOM appeared as a valuable tool for community classification, and to establish clear relationships between clusters of bacterial communities and sole-carbon sources utilization. Specifically, SOM offered a clear bidimensional projection of a relatively large volume of data and were easier to interpret than plots commonly obtained with multivariate analyses. They would be recommended to pattern the temporal evolution of communities' functional diversity.

Calcium Carbonate Precipitation for CO2 Storage and Utilization: A Review of the Carbonate Crystallization and Polymorphism

Directory of Open Access Journals (Sweden)

Ribooga Chang

2017-07-01

Full Text Available The transformation of CO2 into a precipitated mineral carbonate through an ex situ mineral carbonation route is considered a promising option for carbon capture and storage (CCS since (i the captured CO2 can be stored permanently and (ii industrial wastes (i.e., coal fly ash, steel and stainless-steel slags, and cement and lime kiln dusts can be recycled and converted into value-added carbonate materials by controlling polymorphs and properties of the mineral carbonates. The final products produced by the ex situ mineral carbonation route can be divided into two categories—low-end high-volume and high-end low-volume mineral carbonates—in terms of their market needs as well as their properties (i.e., purity. Therefore, it is expected that this can partially offset the total cost of the CCS processes. Polymorphs and physicochemical properties of CaCO3 strongly rely on the synthesis variables such as temperature, pH of the solution, reaction time, ion concentration and ratio, stirring, and the concentration of additives. Various efforts to control and fabricate polymorphs of CaCO3 have been made to date. In this review, we present a summary of current knowledge and recent investigations entailing mechanistic studies on the formation of the precipitated CaCO3 and the influences of the synthesis factors on the polymorphs.

Highly stable rice-straw-derived charcoal in 3700-year-old ancient paddy soil: evidence for an effective pathway toward carbon sequestration.

Science.gov (United States)

Wu, Mengxiong; Yang, Min; Han, Xingguo; Zhong, Ting; Zheng, Yunfei; Ding, Pin; Wu, Weixiang

2016-01-01

Recalcitrant charcoal application is predicted to decelerate global warming through creating a long-term carbon sink in soil. Although many studies have showed high stability of charcoal derived from woody materials, few have focused on the dynamics of straw-derived charcoal in natural environment on a long timescale to evaluate its potential for agricultural carbon sequestration. Here, we examined straw-derived charcoal in an ancient paddy soil dated from ~3700 calendar year before present (cal. year BP). Analytical results showed that soil organic matter consisted of more than 25% of charcoal in charcoal-rich layer. Similarities in morphology and molecular structure between the ancient and the fresh rice-straw-derived charcoal indicated that ancient charcoal was derived from rice straw. The lower carbon content, higher oxygen content, and obvious carbonyl of the ancient charcoal compared with fresh rice straw charcoal implied that oxidation occurred in the scale of thousands years. However, the dominant aromatic C of ancient charcoal indicated that rice-straw-derived charcoal was highly stable in the buried paddy soil due to its intrinsic chemical structures and the physical protection of ancient paddy wetland. Therefore, it may suggest that straw charcoal application is a potential pathway for C sequestration considering its longevity.

Compilation of carbon-14 data

International Nuclear Information System (INIS)

Paasch, R.A.

1985-01-01

A review and critical analysis was made of the original sources of carbon-14 in the graphite moderator and reflector zones of the eight Hanford production reactors, the present physical and chemical state of the carbon-14, pathways (other than direct combustion) by which the carbon-14 could be released to the biosphere, and the maximum rate at which it might be released under circumstances which idealistically favor the release. Areas of uncertainty are noted and recommendations are made for obtaining additional data in three areas: (1) release rate of carbon-14 from irradiated graphite saturated with aerated water; (2) characterization of carbon-14 deposited outside the moderator and reflector zones; and (3) corrosion/release rate of carbon-14 from irradiated steel and aluminum alloys

Feasibility Analyses of Developing Low Carbon City with Hybrid Energy Systems in China: The Case of Shenzhen

Directory of Open Access Journals (Sweden)

Xun Zhang

2016-05-01

Full Text Available As the largest carbon emission source in China, the power sector grows rapidly owing to the country’s unprecedented urbanization and industrialization processes. In order to explore a low carbon urbanization pathway by reducing carbon emissions of the power sector, the Chinese government launched an international low carbon city (ILCC project in Shenzhen. This paper presents a feasibility analysis on the potential hybrid energy system based on local renewable energy resources and electricity demand estimation over the three planning stages of the ILCC project. Wind power, solar power, natural gas and the existing power grid are components considered in the hybrid energy system. The simulation results indicate that the costs of energy in the three planning stages are 0.122, 0.105 and 0.141 $/kWh, respectively, if external wind farms and pumped storage hydro stations (PSHSs exist. The optimization results reveal that the carbon reduction rates are 46.81%, 62.99% and 75.76% compared with the Business as Usual scenarios. The widely distributed water reservoirs in Shenzhen provide ideal conditions to construct PSHS, which is crucial in enhancing renewable energy utilization.

Assessing carbon dioxide removal through global and regional ocean alkalinization under high and low emission pathways

Science.gov (United States)

Lenton, Andrew; Matear, Richard J.; Keller, David P.; Scott, Vivian; Vaughan, Naomi E.

2018-04-01

Atmospheric carbon dioxide (CO2) levels continue to rise, increasing the risk of severe impacts on the Earth system, and on the ecosystem services that it provides. Artificial ocean alkalinization (AOA) is capable of reducing atmospheric CO2 concentrations and surface warming and addressing ocean acidification. Here, we simulate global and regional responses to alkalinity (ALK) addition (0.25 PmolALK yr-1) over the period 2020-2100 using the CSIRO-Mk3L-COAL Earth System Model, under high (Representative Concentration Pathway 8.5; RCP8.5) and low (RCP2.6) emissions. While regionally there are large changes in alkalinity associated with locations of AOA, globally we see only a very weak dependence on where and when AOA is applied. On a global scale, while we see that under RCP2.6 the carbon uptake associated with AOA is only ˜ 60 % of the total, under RCP8.5 the relative changes in temperature are larger, as are the changes in pH (140 %) and aragonite saturation state (170 %). The simulations reveal AOA is more effective under lower emissions, therefore the higher the emissions the more AOA is required to achieve the same reduction in global warming and ocean acidification. Finally, our simulated AOA for 2020-2100 in the RCP2.6 scenario is capable of offsetting warming and ameliorating ocean acidification increases at the global scale, but with highly variable regional responses.

Historical emissions critical for mapping decarbonization pathways

Science.gov (United States)

Majkut, J.; Kopp, R. E.; Sarmiento, J. L.; Oppenheimer, M.

2016-12-01

Policymakers have set a goal of limiting temperature increase from human influence on the climate. This motivates the identification of decarbonization pathways to stabilize atmospheric concentrations of CO2. In this context, the future behavior of CO2 sources and sinks define the CO2 emissions necessary to meet warming thresholds with specified probabilities. We adopt a simple model of the atmosphere-land-ocean carbon balance to reflect uncertainty in how natural CO2 sinks will respond to increasing atmospheric CO2 and temperature. Bayesian inversion is used to estimate the probability distributions of selected parameters of the carbon model. Prior probability distributions are chosen to reflect the behavior of CMIP5 models. We then update these prior distributions by running historical simulations of the global carbon cycle and inverting with observationally-based inventories and fluxes of anthropogenic carbon in the ocean and atmosphere. The result is a best-estimate of historical CO2 sources and sinks and a model of how CO2 sources and sinks will vary in the future under various emissions scenarios, with uncertainty. By linking the carbon model to a simple climate model, we calculate emissions pathways and carbon budgets consistent with meeting specific temperature thresholds and identify key factors that contribute to remaining uncertainty. In particular, we show how the assumed history of CO2 emissions from land use change (LUC) critically impacts estimates of the strength of the land CO2 sink via CO2 fertilization. Different estimates of historical LUC emissions taken from the literature lead to significantly different parameterizations of the carbon system. High historical CO2 emissions from LUC lead to a more robust CO2 fertilization effect, significantly lower future atmospheric CO2 concentrations, and an increased amount of CO2 that can be emitted to satisfy temperature stabilization targets. Thus, in our model, historical LUC emissions have a

A Methodology for a Sustainable CO2 Capture and Utilization Network

DEFF Research Database (Denmark)

Frauzem, Rebecca; Fjellerup, Kasper; Gani, Rafiqul

2015-01-01

hydrogenation highlights the application. This case study illustrates the utility of the utilization network and elements of the methodology being developed. In addition, the conversion process is linked with carbon capture to evaluate the overall sustainability. Finally, the production of the other raw...... of Climate Change. New York: Cambridge University Press, 2007. [2] J. Wilcox, Carbon Capture. New York: Springer, 2012....

Effects of Crack and Climate Change on Service Life of Concrete Subjected to Carbonation

Directory of Open Access Journals (Sweden)

Xiao-Yong Wang

2018-04-01

Full Text Available Carbonation is among the primary reasons for the initiation of the corrosion of steel rebar in reinforced concrete (RC structures. Due to structural loading effects and environmental actions, inevitable cracks have frequently occurred in concrete structures since the early ages. Additionally, climate change, which entails increases in CO2 concentration and environmental temperature, will also accelerate the carbonation of concrete. This article presents an analytical way of predicting the service life of cracked concrete structures considering influences of carbonation and climate change. First, using a hydration model, the quantity of carbonatable materials and concrete porosity were calculated. Carbonation depth was evaluated considering properties of concrete materials and environmental conditions. Second, the influence of cracks on CO2 diffusivity was examined. Carbonation depth for cracked concrete was evaluated using equivalent CO2 diffusivity. The effects of climate change, for example, growing CO2 concentration and environmental temperature, were considered using different schemes of carbonation models. Third, different climate change scenarios (such as Representative Concentration Pathways (RCP 2.6, RCP 4.5, RCP 8.5 and upper 90% confidence interval of RCP 8.5 and time slices (such as 2000 and 2050 were used for case studies. By utilizing the Monte Carlo method, the influences of various climate change scenarios on the service life loss of concrete structures were highlighted.

Organic carbon dynamics in mangrove ecosystems: a review

NARCIS (Netherlands)

Kristensen, E.; Bouillon, S.; Dittmar, T.; Marchand, C.

2008-01-01

Our current knowledge on production, composition, transport, pathways and transformations of organic carbon in tropical mangrove environments is reviewed and discussed. Organic carbon entering mangrove foodwebs is either produced autochthonously or imported by tides and/or rivers. Mangrove litter

Transcriptome-based analysis on carbon metabolism of Haematococcus pluvialis mutant under 15% CO2.

Science.gov (United States)

Li, Ke; Cheng, Jun; Lu, Hongxiang; Yang, Weijuan; Zhou, Junhu; Cen, Kefa

2017-06-01

To elucidate the mechanism underlying the enhanced growth rate in the Haematococcus pluvialis mutated with 60 Co-γ rays and domesticated with 15% CO 2 , transcriptome sequencing was conducted to clarify the carbon metabolic pathways of mutant cells. The CO 2 fixation rate of mutant cells increased to 2.57gL -1 d -1 under 15% CO 2 due to the enhanced photosynthesis, carbon fixation, glycolysis pathways. The upregulation of PetH, ATPF0A and PetJ related to photosynthetic electron transport, ATP synthase and NADPH generation promoted the photosynthesis. The upregulation of genes related to Calvin cycle and ppdK promoted carbon fixation in both C3 and C4 photosynthetic pathways. The reallocation of carbon was also enhanced under 15% CO 2 . The 19-, 14- and 3.5-fold upregulation of FBA, TPI and PK genes, respectively, remarkably promoted the glycolysis pathways. This accelerated the conversion of photosynthetic carbon to pyruvate, which was an essential precursor for astaxanthin and lipids biosynthesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

The utility of the historical record in assessing future carbon budgets

Science.gov (United States)

Millar, R.; Friedlingstein, P.; Allen, M. R.

2017-12-01

It has long been known that the cumulative emissions of carbon dioxide (CO2) is the most physically relevant determiner of long-lived anthropogenic climate change, with an approximately linear relationship between CO2-induced global mean surface warming and cumulative emissions. The historical observational record offers a way to constrain the relationship between cumulative carbon dioxide emission and global mean warming using observations to date. Here we show that simple regression analysis indicates that the 1.5°C carbon budget would be exhausted after nearly three decades of current emissions, substantially in excess of many estimates from Earth System Models. However, there are many reasons to be cautious about carbon budget assessments from the historical record alone. Accounting for the uncertainty in non-CO2 radiative forcing using a simple climate model and a standard optimal fingerprinting detection attribution technique gives substantial uncertainty in the contribution of CO2 warming to date, and hence the transient climate response to cumulative emissions. Additionally, the existing balance between CO2 and non-CO2 forcing may change in the future under ambitious mitigation scenarios as non-CO2 emissions become more (or less) important to global mean temperature changes. Natural unforced variability can also have a substantial impact on estimates of remaining carbon budgets. By examining all warmings of a given magnitude in both the historical record and past and future ESM simulations we quantify the impact unforced climate variability may have on estimates of remaining carbon budgets, derived as a function of estimated non-CO2 warming and future emission scenario. In summary, whilst the historical record can act as a useful test of climate models, uncertainties in the response to future cumulative emissions remain large and extrapolations of future carbon budgets from the historical record alone should be treated with caution.

Novel Pathway for Alcoholic Fermentation of 8-Gluconolactone in the Yeast Saccharomyces bulderi

NARCIS (Netherlands)

Dijken, van J.P.; Tuijl, van A.; Luttik, M.A.H.; Middelhoven, W.J.; Pronk, J.T.

2002-01-01

Under anaerobic conditions, the yeast Saccharomyces bulderi rapidly ferments -gluconolactone to ethanol and carbon dioxide. We propose that a novel pathway for -gluconolactone fermentation operates in this yeast. In this pathway, -gluconolactone is first reduced to glucose via an NADPH-dependent

Carbon Dioxide Utilization (CO2U) ICEF Roadmap 2.0. Draft October 2017

Energy Technology Data Exchange (ETDEWEB)

Sandalow, D; Aines, R; Friedmann, J; McCormick, C; McCoy, S

2017-10-02

Last year, experts from CO₂ Sciences, Columbia University and Valence Strategic came together to develop a roadmap. That document, Carbon Dioxide Utilization ICEF Roadmap 1.0, released at the UNFCCC Marrakesh Climate Change Conference in 2016, surveyed the commercial and technical landscape of CO₂ conversion and use. The document provided extensive background and analysis and has helped to provide a foundation for additional studies, including this one.This roadmap is meant to complement and expand upon the work of its predecessor. Based in part on a workshop at Columbia University’s Center on Global Energy Policy in July 2017, it explores three distinct categories of CO₂-based products, the technologies that can be harnessed to convert CO2 to these products, and the associated research and development needs. It also explores the complicated topic of life cycle analysis—critically important when considering the climate impacts of CO₂ conversion and use—as well as policy tools that could be used to promote CO₂-based products.

Liberating energy from carbon introduction to decarbonization

CERN Document Server

Muradov, Nazim

2014-01-01

Liberating Energy from Carbon analyzes energy options in a carbon-constrained world. Major strategies and pathways to decarbonizing the carbon-intensive economy are laid out with a special emphasis on the prospects of achieving low-risk atmospheric CO2 levels. The opportunities and challenges in developing and bringing to market novel low and zero-carbon technologies are highlighted from technical, economic and environmental viewpoints. This book takes a unique approach by treating carbon in a holistic manner?tracking its complete transformation chain from fossil fuel sources to the unique pro

Carbon fixation and isotope discrimination by a crassulacean plant: dependence on the photoperiod.

Science.gov (United States)

Lerman, J C; Queiroz, O

1974-03-22

Variations of more than 1 percent are observed in the carbon-13 to carbon-12 ratio of extracts of leaves of the succulent Kalanchoe blossfeldiana when the photoperiod is changed from long to short days. This indicates that the mechanism of carbon fixation switches from the Calvin (C(3)) pathway to the Hatch-Slack (C(4)) pathway of primary enzymic operation. The variations observed in the isotope compositions are tentatively explained by a model.

Hybrid capacitors utilizing halogen-based redox reactions at interface between carbon positive electrode and aqueous electrolytes

Science.gov (United States)

Yamazaki, Shigeaki; Ito, Tatsuya; Murakumo, Yuka; Naitou, Masashi; Shimooka, Toshiharu; Yamagata, Masaki; Ishikawa, Masashi

2016-09-01

We propose novel hybrid capacitors (HCs) with electrolyte-involved redox reactions of bromide or iodide species by pretreatment of an activated carbon positive electrode. The treatment is simple; impregnation of pores at an activated carbon fiber cloth (ACFC) as a positive electrode with bromine- or iodine-containing water before cell assembly. The treated positive electrode is applied to a HC cell with a non-treated negative electrode of ACFC and its electrochemical performance is investigated by galvanostatic cycling and leakage current tests. Few studies on such "electrolytic" charge storage systems have provided acceptable capacitor performance because of inevitable self-discharge caused by diffusion of charged species form an electrode to the other one through an electrolyte. Nevertheless, our electrolyte-redox-based HCs show excellent performance without undesirable diffusion of charged species. Moreover, the present HC utilizing a bromide redox system fulfills a practical cell voltage of 1.8 V in spite of an aqueous electrolyte system. This high voltage provides excellent energy density, which is 5 times higher than that in a conventional aqueous electric double-layer capacitor (EDLC), and 1.2 times higher even than that in a 2.7 V-class non-aqueous EDLC, while keeping high charge-discharge rate capability.

Process characteristics for microwave assisted hydrothermal carbonization of cellulose.

Science.gov (United States)

Zhang, Junting; An, Ying; Borrion, Aiduan; He, Wenzhi; Wang, Nan; Chen, Yirong; Li, Guangming

2018-07-01

The process characteristics of microwave assisted hydrothermal carbonization of cellulose was investigated and a first order kinetics model based on carbon concentration was developed. Chemical properties analysis showed that comparing to conventional hydrothermal carbonization, hydrochar with comparable energy properties can be obtained with 5-10 times decrease in reaction time with assistance of microwave heating. Results from kinetics study was in great agreement with experimental analysis, that they both illustrated the predominant mechanism of the reaction depend on variations in the reaction rates of two co-existent pathways. Particularly, the pyrolysis-like intramolecular dehydration reaction was proved to be the predominant mechanism for hydrochar generation under high temperatures. Finally, the enhancement effects of microwave heating were reflected under both soluble and solid pathways in this research, suggesting microwave-assisted hydrothermal carbonization as a more attracting method for carbon-enriched hydrochar recovery. Copyright © 2018 Elsevier Ltd. All rights reserved.

Forensic utility of the carbon isotope ratio of PVC tape backings

Science.gov (United States)

Stern, L. A.; Thompson, A. H.; Mehltretter, A. H.; McLaskey, V.; Parish, A.; Aranda, R.

2008-12-01

Forensic interest in adhesive tapes with PVC-backings (polyvinyl chloride, electrical tapes) derives from their use in construction of improvised explosive devices, drug packaging and in a variety of other illicit activities. Due to the range of physical characteristics and chemical compositions of such tapes, traditional microscopic and chemical analysis of the tape backings and adhesives offer a high degree of discrimination between tapes from different manufacturers and products. To evaluate whether carbon isotope ratios may be able to increase discrimination of electrical tapes, particularly with regards to different tapes of the same product, we assessed the PVC-backings of 87 rolls of black electrical tape for their δ13C values. The adhesive on these tapes was physically removed with hexane, and plasticizers within the PVC tape backings were removed by three-20 minute extractions with chloroform. The δ13C values of the PVC tape backings ranged between -23.8 and -41.5 (‰ V-PDB). The carbon isotopic variation within a product (identical brand and product identification) is significant, based on five products with at least 3 rolls (ranges of 7.4‰ (n=3), 10.0‰ (n=6), 4.2‰ (n=16), 3.8‰ (n=6), and 11.5‰ (n=8), respectively). There was no measurable carbon isotope variation in regards to the following: a) along the length of a roll (4 samples from 1 roll); b) between the center and edge of a strip of tape (1 pair); c) between rolls assumed to be from the same lot of tape (2 pairs); d) between different rolls from the same batch of tape (same product purchased at the same time and place; 5 pairs); and e) between samples of a tape at room temperature, heated to 50° C and 80° C for 1 week. For each sample within the population of 87 tapes, carbon isotopes alone exclude 80 to 100% of the tapes as a potential match, with an average exclusion power of 92.5%, using a window of ± 0.4‰. Carbon isotope variations originate from variations in starting

Wildland fire emissions, carbon, and climate: Seeing the forest and the trees - A cross-scale assessment of wildfire and carbon dynamics in fire-prone, forested ecosystems

Science.gov (United States)

Rachel A. Loehman; Elizabeth Reinhardt; Karin L. Riley

2014-01-01

Wildfires are an important component of the terrestrial carbon cycle and one of the main pathways for movement of carbon from the land surface to the atmosphere. Fires have received much attention in recent years as potential catalysts for shifting landscapes from carbon sinks to carbon sources. Unless structural or functional ecosystem shifts occur, net carbon balance...

Oxygen entry through multiple pathways in T-state human hemoglobin.

Science.gov (United States)

Takayanagi, Masayoshi; Kurisaki, Ikuo; Nagaoka, Masataka

2013-05-23

The heme oxygen (O2) binding site of human hemoglobin (HbA) is buried in the interior of the protein, and there is a debate over the O2 entry pathways from solvent to the binding site. As a first step to understand HbA O2 binding process at the atomic level, we detected all significant multiple O2 entry pathways from solvent to the binding site in the α and β subunits of the T-state tetramer HbA by utilizing ensemble molecular dynamics (MD) simulation. By executing 128 independent 8 ns MD trajectories in O2-rich aqueous solvent, we simulated the O2 entry processes and obtained 141 and 425 O2 entry events in the α and β subunits of HbA, respectively. We developed the intrinsic pathway identification by clustering method to achieve a persuasive visualization of the multiple entry pathways including both the shapes and relative importance of each pathway. The rate constants of O2 entry estimated from the MD simulations correspond to the experimentally observed values, suggesting that O2 ligands enter the binding site through multiple pathways. The obtained multiple pathway map can be utilized for future detailed analysis of HbA O2 binding process.

The Emissions Scenarios Portal: Visualizing Low-Carbon Pathways for the 21st Century

Science.gov (United States)

Hennig, R. J.; Friedrich, J.; Ge, M.; Mountford, H.; Fransen, T.; Altamirano, J. C.; Thanawala, Z.; Arcipowska, A.

2017-12-01

The Emissions Scenarios Portal (ESP) is a newly developed exploration tool for 21st century low-carbon pathways and investigation of the Nationally Determined Contributions (NDC's) that countries have put forward under the Paris Agreement. It is open to the public and aims to help achieve the goal of limiting global temperature increase to well below 2 degrees Celsius above pre-industrial levels by enhancing access to high-quality, up-to-date scenario information. It can guide users to set ambitious, realistic emission mitigation goals and understand what these goals imply for different sectors of the economy. Data will be integrated from a wide variety of economic and energy-system models with results from both national models as well as globally integrated assessment models (IAM's) and countries biennial update reports (BUR's). This information can support policy and investment decision making that will lead to a low carbon future. It is designed to help find answers to questions such as "Are the NDC's enough to put the world on a 2DC track?", "What do NDC's imply for different sectors of the economy under different assumptions?" or "What are good ways to increase ambition beyond NDC's?". The portal strives to achieve both inter-comparability across a wide range of different models and nationally reported scenarios, as well as flexibility to allow modelers to bring out the strengths and purpose of their model on the platform. Furthermore, it aims to enhance standardized and transparent reporting of emissions scenarios and relevant metadata, assumptions and results to improve understanding, accessibility and impact of the scenarios. On the data side, these rivaling objectives present interesting challenges for both the collection and communication of the data and in this presentation we will present some of our ideas for tackling these. This project will be part of Climate Watch, a new data platform developed jointly by the World Resources Institute and the NDC

Prioritizing Popular Proteins in Liver Cancer: Remodelling One-Carbon Metabolism.

Science.gov (United States)

Mora, María Isabel; Molina, Manuela; Odriozola, Leticia; Elortza, Félix; Mato, José María; Sitek, Barbara; Zhang, Pumin; He, Fuchu; Latasa, María Uxue; Ávila, Matías Antonio; Corrales, Fernando José

2017-12-01

Primary liver cancer (HCC) is recognized as the fifth most common neoplasm and the second leading cause of cancer death worldwide. Most risk factors are known, and the molecular pathogenesis has been widely studied in the past decade; however, the underlying molecular mechanisms remain to be unveiled, as they will facilitate the definition of novel biomarkers and clinical targets for more effective patient management. We utilize the B/D-HPP popular protein strategy. We report a list of popular proteins that have been highly cocited with the expression "liver cancer". Several enzymes highlight the known metabolic remodeling of liver cancer cells, four of which participate in one-carbon metabolism. This pathway is central to the maintenance of differentiated hepatocytes, as it is considered the connection between intermediate metabolism and epigenetic regulation. We designed a targeted selective reaction monitoring (SRM) method to follow up one-carbon metabolism adaptation in mouse HCC and in regenerating liver following exposure to CCl 4 . This method allows systematic monitoring of one-carbon metabolism and could prove useful in the follow-up of HCC and of chronically liver-diseased patients (cirrhosis) at risk of HCC. The SRM data are available via ProteomeXchange in PASSEL (PASS01060).

Nanotubes on Display: How Carbon Nanotubes Can Be Integrated into Electronic Displays

KAUST Repository

Opatkiewicz, Justin

2010-06-22

Random networks of single-walled carbon nanotubes show promise for use in the field of flexible electronics. Nanotube networks have been difficult to utilize because of the mixture of electronic types synthesized when grown. A variety of separation techniques have been developed, but few can readily be scaled up. Despite this issue, when metallic percolation pathways can be separated out or etched away, these networks serve as high-quality thinfilm transistors with impressive device characteristics. A new article in this issue illustrates this point and the promise of these materials. With more work, these devices can be implemented in transparent displays in the next generation of hand-held electronics. © 2010 American Chemical Society.

Biological Conversion of Sugars to Hydrocarbons Technology Pathway

Energy Technology Data Exchange (ETDEWEB)

Davis, R.; Biddy, M.; Tan, E.; Tao, L.; Jones, S.

2013-03-01

This technology pathway case investigates the biological conversion of biomass-derived sugars to hydrocarbon biofuels, utilizing data from recent literature references and information consistent with recent pilot-scale demonstrations at NREL. Technical barriers and key research needs have been identified that should be pursued for the pathway to become competitive with petroleum-derived gasoline-, diesel-, and jet-range hydrocarbon blendstocks.

Activated Carbon, Carbon Nanofiber and Carbon Nanotube Supported Molybdenum Carbide Catalysts for the Hydrodeoxygenation of Guaiacol

Directory of Open Access Journals (Sweden)

Eduardo Santillan-Jimenez

2015-03-01

Full Text Available Molybdenum carbide was supported on three types of carbon support—activated carbon; multi-walled carbon nanotubes; and carbon nanofibers—using ammonium molybdate and molybdic acid as Mo precursors. The use of activated carbon as support afforded an X-ray amorphous Mo phase, whereas crystalline molybdenum carbide phases were obtained on carbon nanofibers and, in some cases, on carbon nanotubes. When the resulting catalysts were tested in the hydrodeoxygenation (HDO of guaiacol in dodecane, catechol and phenol were obtained as the main products, although in some instances significant amounts of cyclohexane were produced. The observation of catechol in all reaction mixtures suggests that guaiacol was converted into phenol via sequential demethylation and HDO, although the simultaneous occurrence of a direct demethoxylation pathway cannot be discounted. Catalysts based on carbon nanofibers generally afforded the highest yields of phenol; notably, the only crystalline phase detected in these samples was Mo2C or Mo2C-ζ, suggesting that crystalline Mo2C is particularly selective to phenol. At 350 °C, carbon nanofiber supported Mo2C afforded near quantitative guaiacol conversion, the selectivity to phenol approaching 50%. When guaiacol HDO was performed in the presence of acetic acid and furfural, guaiacol conversion decreased, although the selectivity to both catechol and phenol was increased.

Utilization of ancient permafrost carbon in headwaters of Arctic fluvial networks

NARCIS (Netherlands)

Mann, Paul J.; Eglinton, Timothy I.; McIntyre, Cameron P.; Zimov, Nikita; Davydova, Anna; Vonk, Jorien E.; Holmes, Robert M.; Spencer, Robert G M

2015-01-01

Northern high-latitude rivers are major conduits of carbon from land to coastal seas and the Arctic Ocean. Arctic warming is promoting terrestrial permafrost thaw and shifting hydrologic flowpaths, leading to fluvial mobilization of ancient carbon stores. Here we describe 14 C and 13 C

Small molecule inhibitors of the Candida albicans budded-to-hyphal transition act through multiple signaling pathways.

Directory of Open Access Journals (Sweden)

John Midkiff

Full Text Available The ability of the pathogenic yeast Candida albicans to interconvert between budded and hyphal growth states, herein termed the budded-to-hyphal transition (BHT, is important for C. albicans development and virulence. The BHT is under the control of multiple cell signaling pathways that respond to external stimuli, including nutrient availability, high temperature, and pH. Previous studies identified 21 small molecules that could inhibit the C. albicans BHT in response to carbon limitation in Spider media. However, the studies herein show that the BHT inhibitors had varying efficacies in other hyphal-inducing media, reflecting their varying abilities to block signaling pathways associated with the different media. Chemical epistasis analyses suggest that most, but not all, of the BHT inhibitors were acting through either the Efg1 or Cph1 signaling pathways. Notably, the BHT inhibitor clozapine, a FDA-approved drug used to treat atypical schizophrenia by inhibiting G-protein-coupled dopamine receptors in the brain, and several of its functional analogs were shown to act at the level of the Gpr1 G-protein-coupled receptor. These studies are the first step in determining the target and mechanism of action of these BHT inhibitors, which may have therapeutic anti-fungal utility in the future.

The Aspergillus nidulans acuL gene encodes a mitochondrial carrier required for the utilization of carbon sources that are metabolized via the TCA cycle.

Science.gov (United States)

Flipphi, Michel; Oestreicher, Nathalie; Nicolas, Valérie; Guitton, Audrey; Vélot, Christian

2014-07-01

In Aspergillus nidulans, the utilization of acetate as sole carbon source requires several genes (acu). Most of them are also required for the utilization of fatty acids. This is the case for acuD and acuE, which encode the two glyoxylate cycle-specific enzymes, isocitrate lyase and malate synthase, respectively, but also for acuL that we have identified as AN7287, and characterized in this study. Deletion of acuL resulted in the same phenotype as the original acuL217 mutant. acuL encodes a 322-amino acid protein which displays all the structural features of a mitochondrial membrane carrier, and shares 60% identity with the Saccharomyces cerevisiae succinate/fumarate mitochondrial antiporter Sfc1p (also named Acr1p). Consistently, the AcuL protein was shown to localize in mitochondria, and partial cross-complementation was observed between the S. cerevisiae and A. nidulans homologues. Extensive phenotypic characterization suggested that the acuL gene is involved in the utilization of carbon sources that are catabolized via the TCA cycle, and therefore require gluconeogenesis. In addition, acuL proves to be co-regulated with acuD and acuE. Overall, our data suggest that AcuL could link the glyoxylate cycle to gluconeogenesis by exchanging cytoplasmic succinate for mitochondrial fumarate. Copyright © 2014 Elsevier Inc. All rights reserved.

Membrane/mediator-free rechargeable enzymatic biofuel cell utilizing graphene/single-wall carbon nanotube cogel electrodes.

Science.gov (United States)

Campbell, Alan S; Jeong, Yeon Joo; Geier, Steven M; Koepsel, Richard R; Russell, Alan J; Islam, Mohammad F

2015-02-25

Enzymatic biofuel cells (EBFCs) utilize enzymes to convert chemical energy present in renewable biofuels into electrical energy and have shown much promise in the continuous powering of implantable devices. Currently, however, EBFCs are greatly limited in terms of power and operational stability with a majority of reported improvements requiring the inclusion of potentially toxic and unstable electron transfer mediators or multicompartment systems separated by a semipermeable membrane resulting in complicated setups. We report on the development of a simple, membrane/mediator-free EBFC utilizing novel electrodes of graphene and single-wall carbon nanotube cogel. These cogel electrodes had large surface area (∼ 800 m(2) g(-1)) that enabled high enzyme loading, large porosity for unhindered glucose transport and moderate electrical conductivity (∼ 0.2 S cm(-1)) for efficient charge collection. Glucose oxidase and bilirubin oxidase were physically adsorbed onto these electrodes to form anodes and cathodes, respectively, and the EBFC produced power densities up to 0.19 mW cm(-2) that correlated to 0.65 mW mL(-1) or 140 mW g(-1) of GOX with an open circuit voltage of 0.61 V. Further, the electrodes were rejuvenated by a simple wash and reloading procedure. We postulate these porous and ultrahigh surface area electrodes will be useful for biosensing applications, and will allow reuse of EBFCs.

Prokaryotic Heme Biosynthesis: Multiple Pathways to a Common Essential Product.

Science.gov (United States)

Dailey, Harry A; Dailey, Tamara A; Gerdes, Svetlana; Jahn, Dieter; Jahn, Martina; O'Brian, Mark R; Warren, Martin J

2017-03-01

The advent of heme during evolution allowed organisms possessing this compound to safely and efficiently carry out a variety of chemical reactions that otherwise were difficult or impossible. While it was long assumed that a single heme biosynthetic pathway existed in nature, over the past decade, it has become clear that there are three distinct pathways among prokaryotes, although all three pathways utilize a common initial core of three enzymes to produce the intermediate uroporphyrinogen III. The most ancient pathway and the only one found in the Archaea converts siroheme to protoheme via an oxygen-independent four-enzyme-step process. Bacteria utilize the initial core pathway but then add one additional common step to produce coproporphyrinogen III. Following this step, Gram-positive organisms oxidize coproporphyrinogen III to coproporphyrin III, insert iron to make coproheme, and finally decarboxylate coproheme to protoheme, whereas Gram-negative bacteria first decarboxylate coproporphyrinogen III to protoporphyrinogen IX and then oxidize this to protoporphyrin IX prior to metal insertion to make protoheme. In order to adapt to oxygen-deficient conditions, two steps in the bacterial pathways have multiple forms to accommodate oxidative reactions in an anaerobic environment. The regulation of these pathways reflects the diversity of bacterial metabolism. This diversity, along with the late recognition that three pathways exist, has significantly slowed advances in this field such that no single organism's heme synthesis pathway regulation is currently completely characterized. Copyright © 2017 American Society for Microbiology.

Kyoto : implications for utility regulation

International Nuclear Information System (INIS)

Dunsky, P.

2003-01-01

The author provided a historical perspective of energy use and the role of carbon in the western hemisphere by displaying a series of graphs showing carbon intensity of energy, carbon emissions from energy, and the long path to green power. The 1990s represented a decade of progress. Almost three times as much wind capacity as nuclear capacity was added worldwide in 2001. The main challenge for the 21st century will be to bring under-developed countries into the fold while perpetuating the economic and human progress of the twentieth century. It was emphasized that environmental damage caused by utilities must be reversed. The contemporary context for the Kyoto Protocol was reviewed. Canada's commitment under the Kyoto Protocol is to reduce greenhouse gas emissions by 6 per cent below 1990 levels. The challenge for utility regulators to meet this commitment was examined. The costs are not entirely excessive. Some of the regulatory issues were discussed, namely revising a broad rate making framework, cost recovery and others. The Kyoto compliance plan was also reviewed with reference to internal options, external options, identification of regulatory barriers, and consideration of greenhouse gas credit markets. figs

Quantitative iTRAQ-based secretome analysis reveals species-specific and temporal shifts in carbon utilization strategies among manganese(II)-oxidizing Ascomycete fungi

Energy Technology Data Exchange (ETDEWEB)

Zeiner, Carolyn A.; Purvine, Samuel O.; Zink, Erika M.; Paša-Tolić, Ljiljana; Chaput, Dominique L.; Wu, Si; Santelli, Cara M.; Hansel, Colleen M.

2017-09-01

Fungi generate a wide range of extracellular hydrolytic and oxidative enzymes and reactive metabolites, collectively known as the secretome, that synergistically drive plant litter decomposition in the environment. While secretome studies of model organisms have greatly expanded our knowledge of these enzymes, few have extended secretome characterization to environmental isolates or directly compared temporal patterns of enzyme utilization among diverse species. Thus, the mechanisms of carbon (C) degradation by many ubiquitous soil fungi remain poorly understood. Here we use a combination of iTRAQ proteomics and custom bioinformatic analyses to compare the protein composition of the secretomes of four manganese(II)-oxidizing Ascomycete fungi over a three-week time course. We demonstrate that although the fungi produce a similar suite of extracellular enzymes, they exhibit striking differences in the regulation of these enzymes among species and over time, revealing species-specific and temporal shifts in C utilization strategies as they degrade the same substrate. Specifically, our findings suggest that Paraconiothyrium sporulosum AP3s5-JAC2a and Alternaria alternata SRC1lrK2f employ sequential enzyme secretion patterns concomitant with decreasing resource availability, Stagonospora sp. SRC1lsM3a preferentially degrades proteinaceous substrate before switching to carbohydrates, and Pyrenochaeta sp. DS3sAY3a utilizes primarily peptidases to aggressively attack carbon sources in a concentrated burst. This work highlights the diversity of operative metabolic strategies among cellulose-degrading Ascomycetes and enhances our understanding of their role in C turnover in the environment.

Relationship between Water and Carbon Utilization under Different Straw Mulching and Plant Density of Summer Maize in North China Plain

Science.gov (United States)

Liu, Quanru; Du, Shoujian; Yin, Honglian; Wang, Juan

2018-03-01

To explore the relationship between water and carbon utilization and key factors to keep high water use efficiency (WUE), a 2-yr experiment was conduct by covering 0 and 0.6 kg m-2 straw to the surface of soil with plant densities of 1.0 × 105, 7.5 × 104, and 5.5 × 104 plants ha-1 in North China Plain during summer maize growing seasons of the 2012 and 2013. Results showed that straw mulching not only increased grain yield (GY), WUE, and carbon efficient ratio (CER) but also inhibited CO2 emission significantly. WUE positively correlated with CER, GY and negative correlated with evapotranspiration (ET) and CO2 emission. CER had the larger direct effect on WUE compared with ET and CO2 emission. The results indicate that straw mulching management in summer maize growing seasons could make sense for inhibiting CO2 emission.

Funding pathways to a low-carbon transition

DEFF Research Database (Denmark)

Foulds, Chris; Christensen, Toke Haunstrup

2016-01-01

The framing of funding programmes can sustain existing ways of conceptualizing particular problems, as well as create new ones. Yet, without more prominent roles for social sciences and humanities, the techno-economic conceptualization of energy consumers could hinder long-term low-carbon aspirat......The framing of funding programmes can sustain existing ways of conceptualizing particular problems, as well as create new ones. Yet, without more prominent roles for social sciences and humanities, the techno-economic conceptualization of energy consumers could hinder long-term low...

Starch and starch hydrolysates are favorable carbon sources for bifidobacteria in the human gut.

Science.gov (United States)

Liu, Songling; Ren, Fazheng; Zhao, Liang; Jiang, Lu; Hao, Yanling; Jin, Junhua; Zhang, Ming; Guo, Huiyuan; Lei, Xingen; Sun, Erna; Liu, Hongna

2015-03-01

Bifidobacteria are key commensals in human gut, and their abundance is associated with the health of their hosts. Although they are dominant in infant gut, their number becomes lower in adult gut. The changes of the diet are considered to be main reason for this difference. Large amounts of whole-genomic sequence data of bifidobacteria make it possible to elucidate the genetic interpretation of their adaptation to the nutrient environment. Among the nutrients in human gut, starch is a highly fermentable substrate and can exert beneficial effects by increasing bifidobacteria and/or being fermented to short chain fatty acids. In order to determine the potential substrate preference of bifidobacteria, we compared the glycoside hydrolase (GH) profiles of a pooled-bifidobacterial genome (PBG) with a representative microbiome (RM) of the human gut. In bifidobacterial genomes, only 15% of GHs contained signal peptides, suggesting their weakness in utilization of complex carbohydrate, such as plant cell wall polysaccharides. However, compared with other intestinal bacteria, bifidobacteiral genomes encoded more GH genes for degrading starch and starch hydrolysates, indicating that they have genetic advantages in utilizing these substrates. Bifidobacterium longum subsp. longum BBMN68 isolated from centenarian's faeces was used as a model strain to further investigate the carbohydrate utilization. The pathway for degrading starch and starch hydrolysates was the only complete pathway for complex carbohydrates in human gut. It is noteworthy that all of the GH genes for degrading starch and starch hydrolysates in the BBMN68 genome were conserved in all studied bifidobacterial strains. The in silico analyses of BBMN68 were further confirmed by growth experiments, proteomic and real-time quantitative PCR (RT-PCR) analyses. Our results demonstrated that starch and starch hydrolysates were the most universal and favorable carbon sources for bifidobacteria. The low amount of these

DEVELOPMENT OF ACTIVATED CARBONS FROM COAL COMBUSTION BY-PRODUCTS

Energy Technology Data Exchange (ETDEWEB)

Harold H. Schobert; M. Mercedes Maroto-Valer; Zhe Lu

2003-09-30

The increasing role of coal as a source of energy in the 21st century will demand environmental and cost-effective strategies for the use of coal combustion by-products (CCBPs), mainly unburned carbon in fly ash. Unburned carbon is nowadays regarded as a waste product and its fate is mainly disposal, due to the present lack of efficient routes for its utilization. However, unburned carbon is a potential precursor for the production of adsorbent carbons, since it has gone through a devolatilization process while in the combustor, and therefore, only requires to be activated. Accordingly, the principal objective of this work was to characterize and utilize the unburned carbon in fly ash for the production of activated carbons. The unburned carbon samples were collected from different combustion systems, including pulverized utility boilers, a utility cyclone, a stoker, and a fluidized bed combustor. LOI (loss-on-ignition), proximate, ultimate, and petrographic analyses were conducted, and the surface areas of the samples were characterized by N2 adsorption isotherms at 77K. The LOIs of the unburned carbon samples varied between 21.79-84.52%. The proximate analyses showed that all the samples had very low moisture contents (0.17 to 3.39 wt %), while the volatile matter contents varied between 0.45 to 24.82 wt%. The elemental analyses show that all the unburned carbon samples consist mainly of carbon with very little hydrogen, nitrogen, sulfur and oxygen In addition, the potential use of unburned carbon as precursor for activated carbon (AC) was investigated. Activated carbons with specific surface area up to 1075m{sup 2}/g were produced from the unburned carbon. The porosity of the resultant activated carbons was related to the properties of the unburned carbon feedstock and the activation conditions used. It was found that not all the unburned carbon samples are equally suited for activation, and furthermore, their potential as activated carbons precursors could be

The carbon footprint of cataract surgery.

Science.gov (United States)

Morris, D S; Wright, T; Somner, J E A; Connor, A

2013-04-01

Climate change is predicted to be one of the largest global health threats of the 21st century. Health care itself is a large contributor to carbon emissions. Determining the carbon footprint of specific health care activities such as cataract surgery allows the assessment of associated emissions and identifies opportunities for reduction. To assess the carbon footprint of a cataract pathway in a British teaching hospital. This was a component analysis study for one patient having first eye cataract surgery in the University Hospital of Wales, Cardiff. Activity data was collected from three sectors, building and energy use, travel and procurement. Published emissions factors were applied to this data to provide figures in carbon dioxide equivalents (CO2eq). The carbon footprint for one cataract operation was 181.8 kg CO2eq. On the basis that 2230 patients were treated for cataracts during 2011 in Cardiff, this has an associated carbon footprint of 405.4 tonnes CO2eq. Building and energy use was estimated to account for 36.1% of overall emissions, travel 10.1% and procurement 53.8%, with medical equipment accounting for the most emissions at 32.6%. This is the first published carbon footprint of cataract surgery and acts as a benchmark for other studies as well as identifying areas for emissions reduction. Within the procurement sector, dialogue with industry is important to reduce the overall carbon footprint. Sustainability should be considered when cataract pathways are designed as there is potential for reduction in all sectors with the possible side effects of saving costs and improving patient care.

Composite carbon foam electrode

Science.gov (United States)

Mayer, Steven T.; Pekala, Richard W.; Kaschmitter, James L.

1997-01-01

Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivty and power to system energy.

Pathways analysis and radiation-dose estimates for radioactive residues at formerly utilized MED/AEC sites

Energy Technology Data Exchange (ETDEWEB)

Gilbert, T.L.; Chee, P.C.; Knight, M.J.; Peterson, J.M.; Roberts, C.J.; Robinson, J.E.; Tsai, S.Y.H.; Yuan, Y.C.

1983-03-01

Methods of analysis are developed for estimating the largest individual radiation dose that could result from residual radioactivity at sites identified by the Formerly Utilized Sites Remedial Action Program (FUSRAP) of the US Department of Energy. Two unique aspects of the methods are (1) a systematic structuring of the radiation pathways analysis into source terms, source-to-exposure analysis, and exposure-to-dose analysis, and (2) the systematic use of data on the average concentrations of naturally occurring radionuclides in soil, food, and the human body in order to assess the validity of model calculations and obtain more realistic values. The methods are applied to a typical FUSRAP site in order to obtain generic source-to-dose (D/S) conversion factors for estimating the radiation dose to the maximally exposed individual from a known concentration of radionuclides in the soil. The D/S factors are used to derive soil guidelines, i.e., the limiting concentrations of radionuclides at a typical FUSRAP site that are unlikely to result in individual dose limits that exceed generally accepted radiation protection standards. The results lead to the conclusion that the soil guidelines should not exceed 17, 75, and 300 pCi/g for Ra-226, U-238, and Th-230, respectively.

Pathways analysis and radiation-dose estimates for radioactive residues at formerly utilized MED/AEC sites

International Nuclear Information System (INIS)

Gilbert, T.L.; Chee, P.C.; Knight, M.J.; Peterson, J.M.; Roberts, C.J.; Robinson, J.E.; Tsai, S.Y.H.; Yuan, Y.C.

1983-03-01

Methods of analysis are developed for estimating the largest individual radiation dose that could result from residual radioactivity at sites identified by the Formerly Utilized Sites Remedial Action Program (FUSRAP) of the US Department of Energy. Two unique aspects of the methods are (1) a systematic structuring of the radiation pathways analysis into source terms, source-to-exposure analysis, and exposure-to-dose analysis, and (2) the systematic use of data on the average concentrations of naturally occurring radionuclides in soil, food, and the human body in order to assess the validity of model calculations and obtain more realistic values. The methods are applied to a typical FUSRAP site in order to obtain generic source-to-dose (D/S) conversion factors for estimating the radiation dose to the maximally exposed individual from a known concentration of radionuclides in the soil. The D/S factors are used to derive soil guidelines, i.e., the limiting concentrations of radionuclides at a typical FUSRAP site that are unlikely to result in individual dose limits that exceed generally accepted radiation protection standards. The results lead to the conclusion that the soil guidelines should not exceed 17, 75, and 300 pCi/g for Ra-226, U-238, and Th-230, respectively

Catalytic Upgrading of Sugars to Hydrocarbons Technology Pathway

Energy Technology Data Exchange (ETDEWEB)

Biddy, M.; Jones, S.

2013-03-01

This technology pathway case investigates the catalytic conversion of solubilized carbohydrate streams to hydrocarbon biofuels, utilizing data from recent efforts within the National Advanced Biofuels Consortium (NABC) in collaboration with Virent, Inc. Technical barriers and key research needs that should be pursued for the catalytic conversion of sugars pathway to be competitive with petroleum-derived gasoline-, diesel-, and jet-range hydrocarbon blendstocks have been identified.

Thermophilic anaerobic acetate-utilizing methanogens and their metabolism

DEFF Research Database (Denmark)

Mladenovska, Zuzana

Six strains of thermophilic anaerobic acetate-utilizing methanogens were isolated from different full-scale thermophilic biogas plants in China and Denmark. The strain isolated from the Chinese biogas plant was designated KN-6P and the isolates from the Danish full-scale biogas plants were......, utilizing the substrates acetate, methanol and methylamines but not hydrogen/carbon dioxide. Strain Methanosarcina sp. SO-2P was able to grow mixotrophically on methanol and hydrogen/carbon dioxide with methane formation from hydrogen and carbon dioxide occurring after methanol depletion. All six...... designated HG-1P, LVG-4P R1-1P, SO-2P and V-1P. The isolates were characterized morphologically and physiologically, and their immunological and phylogenetic relatedness to already known isolated strains were established. All isolated strains were identified as organisms belonging to genus Methanosarcina...

Non-riverine pathways of terrigenous carbon to the ocean

Science.gov (United States)

Dittmar, T.

2007-12-01

The extent and nature of non-riverine fluxes of carbon from land to ocean are poorly understood. Tidal pumping from highly productive coastal environments, atmospheric deposition and submarine groundwater discharge can be significant transport mechanisms for carbon to the ocean. Evidence is mounting that tidally-induced porewater fluxes ("outwelling") of dissolved organic matter (DOM) from mangroves and salt marshes alone may be similar in magnitude as the global riverine flux of DOM. Tidal pumping of dissolved inorganic carbon (DIC) might exceed organic carbon fluxes by far, but the existing knowledge on DIC outwelling is too scarce for a first global estimate. Results from two case studies on the biogeochemistry of DOM outwelling are presented, from the mangroves in Northern Brazil and the salt marshes in the Northern Gulf of Mexico. Ongoing research in the Northern Gulf of Mexico indicates that outwelling and groundwater inputs probably exceed riverine DOM fluxes in this region. Similar observations were made in Northern Brazil. There, the fate of mangrove-derived DOM could be traced from its source in the mangrove sediments to the outer North Brazil shelf by using a combination of isotopic and molecular approaches. Reversed-phase liquid chromatography / mass spectrometry (LC/MS) provided a multifaceted array of information that mirrors the molecular complexity of DOM. Statistical analyses on these data revealed significant differences between mangrove and open-ocean DOM which successively disappeared by irradiating the samples with natural sunlight. Nuclear magnetic resonance analyses yielded concurrent results. Ultrahigh-resolution Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) is the only technique capable of resolving and identifying individual elemental compositions in these complex mixtures. We applied this technique for characterizing mangrove-derived DOM and to assess the molecular changes that occur in the initial stages of

Calcium Carbonate Precipitation for CO{sub 2} Storage and Utilization: A Review of the Carbonate Crystallization and Polymorphism

Energy Technology Data Exchange (ETDEWEB)

Chang, Ribooga; Kim, Semin; Lee, Seungin; Choi, Soyoung; Kim, Minhee; Park, Youngjune, E-mail: young@gist.ac.kr [Carbon and Energy Systems, School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju (Korea, Republic of)

2017-07-10

The transformation of CO{sub 2} into a precipitated mineral carbonate through an ex situ mineral carbonation route is considered a promising option for carbon capture and storage (CCS) since (i) the captured CO{sub 2} can be stored permanently and (ii) industrial wastes (i.e., coal fly ash, steel and stainless-steel slags, and cement and lime kiln dusts) can be recycled and converted into value-added carbonate materials by controlling polymorphs and properties of the mineral carbonates. The final products produced by the ex situ mineral carbonation route can be divided into two categories—low-end high-volume and high-end low-volume mineral carbonates—in terms of their market needs as well as their properties (i.e., purity). Therefore, it is expected that this can partially offset the total cost of the CCS processes. Polymorphs and physicochemical properties of CaCO{sub 3} strongly rely on the synthesis variables such as temperature, pH of the solution, reaction time, ion concentration and ratio, stirring, and the concentration of additives. Various efforts to control and fabricate polymorphs of CaCO{sub 3} have been made to date. In this review, we present a summary of current knowledge and recent investigations entailing mechanistic studies on the formation of the precipitated CaCO{sub 3} and the influences of the synthesis factors on the polymorphs.

Impact of dissolution and carbonate precipitation on carbon storage in basalt

Science.gov (United States)

Wells, R. K.; Xiong, W.; Tadeoye, J.; Menefee, A.; Ellis, B. R.; Skemer, P. A.; Giammar, D.

2016-12-01

The spatial evolution of silicate mineral dissolution, carbonate precipitation, and the transport of fluids influence the viability of carbon storage in basalt reservoirs. Dissolution of natural basalt and subsequent carbonate precipitation in systems with different transport processes operating were characterized using static and flow-through (5 mL/hr) experiments at 50, 100, and 150 °C, and 100 bar CO2. Intact samples and cores with milled pathways that simulate fractures were tested. Spatial and mineralogical patterns in dissolution and precipitation were analyzed using optical and electron microscopy, microCT scanning, and surface roughness data. Precipitates and fluid chemistry were analyzed using Raman spectroscopy, SEM-EDS, and ICP-MS. Analysis of the bulk solution and surface topography suggests dissolution of olivine and pyroxene grains begins within hours of the start of the experiments. In flow-through experiments, total effluent cation concentrations reach a peak concentration within a few hours then drop towards a steady state within a few days. In static experiments, the initial rate of cation release is faster than it is after several weeks. In both cases Ca2+, Mg2+, and Fe2+ are the dominant cations in solution in the initial stages of reaction. Lower concentrations of Na2+, K+, and Al3+, and the preservation of feldspar and matrix grains after several weeks of reaction indicate the slow reactivity of these minerals. As the reaction progresses, the surface roughness increases steadily with cavities developing at the sites of olivine and pyroxene grains. Post-reaction analysis of basalt samples reacted at static conditions with milled pathways reveals that both siderite and amorphous silica precipitated within diffusion-limited zones as early as 4-6 weeks. Siderite abundance varies with distance along the pathway with the highest concentration of carbonates 1-2 cm below the fracture opening. Siderite precipitates are large enough to fill fracture

Metabolic Characteristics of a Glucose-Utilizing Shewanella oneidensis Strain Grown under Electrode-Respiring Conditions.

Directory of Open Access Journals (Sweden)

Gen Nakagawa

Full Text Available In bioelectrochemical systems, the electrode potential is an important parameter affecting the electron flow between electrodes and microbes and microbial metabolic activities. Here, we investigated the metabolic characteristics of a glucose-utilizing strain of engineered Shewanella oneidensis under electrode-respiring conditions in electrochemical reactors for gaining insight into how metabolic pathways in electrochemically active bacteria are affected by the electrode potential. When an electrochemical reactor was operated with its working electrode poised at +0.4 V (vs. an Ag/AgCl reference electrode, the engineered S. oneidensis strain, carrying a plasmid encoding a sugar permease and glucose kinase of Escherichia coli, generated current by oxidizing glucose to acetate and produced D-lactate as an intermediate metabolite. However, D-lactate accumulation was not observed when the engineered strain was grown with a working electrode poised at 0 V. We also found that transcription of genes involved in pyruvate and D-lactate metabolisms was upregulated at a high electrode potential compared with their transcription at a low electrode potential. These results suggest that the carbon catabolic pathway of S. oneidensis can be modified by controlling the potential of a working electrode in an electrochemical bioreactor.

Fundamental study of low-NOx combustion fly ash utilization

International Nuclear Information System (INIS)

Suuberg, Eric M.; Hurt, Robert H.

1998-01-01

This study is principally concerned with characterizing the organic part of coal combustion fly ashes. High carbon fly ashes are becoming more common as by-products of low-NOx combustion technology, and there is need to learn more about this fraction of the fly ash. The project team consists of two universities, Brown and Princeton, and an electrical utility, New England Power. A sample suite of over fifty fly ashes has been gathered from utilities across the United States, and includes ashes from a coals ranging in rank from bituminous to lignite. The characterizations of these ashes include standard tests (LOI, Foam Index), as well as more detailed characterizations of their surface areas, porosity, extractability and adsorption behavior. The ultimate goal is, by better characterizing the material, to enable broadening the range of applications for coal fly ash re-use beyond the current main market as a pozzolanic agent for concretes. The potential for high carbon-content fly ashes to substitute for activated carbons is receiving particular attention. The work performed to date has already revealed how very different the surfaces of different ashes produced by the same utility can be, with respect to polarity of the residual carbon. This can help explain the large variations in acceptability of these ashes as concrete additives

Improvement of Carbon Dioxide Sweep Efficiency by Utilization of Microbial Permeability Profile Modification to Reduce the Amount of Oil Bypassed During Carbon Dioxide Flood

Energy Technology Data Exchange (ETDEWEB)

Schmitz, Darrel [Mississippi State Univ., Mississippi State, MS (United States); Brown, Lewis [Mississippi State Univ., Mississippi State, MS (United States); Lynch, F. Leo [Mississippi State Univ., Mississippi State, MS (United States); Kirkland, Brenda L. [Mississippi State Univ., Mississippi State, MS (United States); Collins, Krystal M. [Mississippi State Univ., Mississippi State, MS (United States); Funderburk, William K. [Mississippi State Univ., Mississippi State, MS (United States)

2010-12-31

The objective of this project was to couple microbial permeability profile modification (MPPM), with carbon dioxide flooding to improve oil recovery from the Upper Cretaceous Little Creek Oil Field situated in Lincoln and Pike counties, MS. This study determined that MPPM technology, which improves production by utilizing environmentally friendly nutrient solutions to simulate the growth of the indigenous microflora in the most permeable zones of the reservoir thus diverting production to less permeable, previously unswept zones, increased oil production without interfering with the carbon dioxide flooding operation. Laboratory tests determined that no microorganisms were produced in formation waters, but were present in cores. Perhaps the single most significant contribution of this study is the demonstration that microorganisms are active at a formation temperature of 115°C (239°F) by using a specially designed culturing device. Laboratory tests were employed to simulate the MPPM process by demonstrating that microorganisms could be activated with the resulting production of oil in coreflood tests performed in the presence of carbon dioxide at 66°C (the highest temperature that could be employed in the coreflood facility). Geological assessment determined significant heterogeneity in the Eutaw Formation, and documented relatively thin, variably-lithified, well-laminated sandstone interbedded with heavily-bioturbated, clay-rich sandstone and shale. Live core samples of the Upper Cretaceous Eutaw Formation from the Heidelberg Field, MS were quantitatively assessed using SEM, and showed that during MPPM permeability modification occurs ubiquitously within pore and throat spaces of 10-20 μm diameter. Testing of the MPPM procedure in the Little Creek Field showed a significant increase in production occurred in two of the five production test wells; furthermore, the decline curve in each of the production wells became noticeably less steep. This project greatly

The effect of carbon tax on carbon emission abatement and GDP: a case study

Science.gov (United States)

Liu, Xiao; Leung, Yee; Xu, Yuan; Yung, Linda Chor Wing

2017-10-01

Carbon tax has been advocated as an effective economic instrument for the abatement of CO2 emission by various countries, including China, the world's biggest carbon emission country. However, carbon emission abatement cannot be done while ignoring the impact on economic growth. A delicate balance needs to be achieved between the two to find an appropriate pathway for sustainable development. This paper applies a multi-objective optimization approach to analyze the impact of levying carbon tax on the energy-intensive sectors of Guangdong province in China under the constraint of emission reduction target. This approach allows us to evaluate carbon emission minimization while maximizing GDP. For policy analysis, we construct five scenarios for evaluation and optimal choice. The results of the analysis show that a lower initial carbon tax rate is not necessarily better, and that a carbon tax is an effective means to reduce CO2 emissions while maintaining a certain level of GDP growth.

Carbon filter property detection with thermal neutron technique

International Nuclear Information System (INIS)

Deng Zhongbo; Han Jun; Li Wenjie

2003-01-01

The paper discussed the mechanism that the antigas property of the carbon filter will decrease because of its carbon bed absorbing water from the air while the carbon filter is being stored, and introduced the principle and method of detection the amount of water absorption with thermal neutron technique. Because some certain relation between the antigas property of the carbon filter and the amount of water absorption exists, the decrease degree of the carbon filter antigas property can be estimated through the amount of water absorption, offering a practicable facility technical pathway to quickly non-destructively detect the carbon filter antigas property

Hydrogen fuel : well-to-pump pathways for 2050

Energy Technology Data Exchange (ETDEWEB)

Molburg, J. [Argonne National Lab., IL (United States); Mintz, M.; Folga, S.; Gillette, J.

2002-07-01

The authors discussed the topic of hydrogen fuels, and began the presentation by stating that the carbon intensity of world primary energy has been falling and hydrogen intensity has been rising. The declines in carbon can be explained by efficiency gains and fuel switches. There are several alternatives to gasoline fuel for vehicles, such as hydrogen, compressed natural gas, compressed natural gas/hydrogen. Emissions of greenhouse gases in the atmosphere represent a growing concern. The authors discussed four hydrogen pathways that have been modeled. They indicated that both natural gas pathways required additional natural gas transmission and storage. To better illustrate the hydrogen pathway, a conceptual representation of hydrogen pipeline loop supporting local hydrogen delivery was displayed. Some hydrogen distribution assumptions for centralized hydrogen production were examined. A cost modeling procedure was described, with the following topics: defining paths, determining tank-in fuel requirement, size pathway components, estimating component costs, and calculating pathway costs. The results indicated that the natural gas-based pathways were sensitive to feedstock cost, while coal and nuclear were not. Some of the conclusions that were arrived at were: (1) on a well-to-pump basis, with current technologies, the unit cost of hydrogen is expected to be 2 to 3 time that of gasoline, (2) the mpge of hydrogen-fueled vehicles must be more than double gasoline, and (3) hydrogen transport and production are the largest components of all pathways. For the future, the focus has to be on transition, including total and unit costs through study time frame, penetration of hydrogen blends, and niche markets. One must compare apples to apples, i e cost of infrastructure components over time, and learning curves. Pathways and scenarios must be re-examined, to include issues such as truck, rail marine market penetration; and hydrogen carrier pathways. Disruptive

Utilization of Cacao Pod Husk (Theobroma cacao l.) as Activated Carbon and Catalyst in Biodiesel Production Process from Waste Cooking Oil

Science.gov (United States)

Rachmat, Devita; Johar Mawarani, Lizda; Dewi Risanti, Doty

2018-01-01

Cocoa pod husk (Theobroma cacao l.) is a waste from cocoa beans processing. In this research we employ cocoa pod husk as activated carbon to decrease the value of FFA (Free Fatty Acid) in waste cooking oil and as K2CO3 catalyst in biodiesel production process from waste cooking oil. Cocoa pod husk was crusched and grounded into powder that passed thorugh 60 mesh-screen. As activated carbon, cocoa pod husk was firstly carbonized at three variant temperatures i.e 250°C, 300°C and 350°C. The activation process was done using HCl 2M as activator. Based on the results of XRD and FTIR, the carbonization at all variant temperatures does not cause a significant changes in terms of crystallite structure and water content. The pore of activated carbon started to form in sample that was carbonized at 350°C resulting in pore diameter of 5.14644 nm. This result was supported by the fact that the ability of this activated carbon in reducing the FFA of waste cooking oil was the most pronounced one, i.e. up to 86.7% of FFA. It was found that the performance of cocoa pod husk’s activated carbon in reducing FFA is more effective than esterification using H2SO4 which can only decrease 80.8%. On the other hand, the utilization as K2CO3 catalyst was carried out by carbonization at temperature 650°C and extraction using aquadest solvent. The extraction of cocoa pod husk produced 7.067% K2CO3 catalyst. According to RD results the fraction of K2CO3 compound from the green catalysts is the same as the commercial (SAP, 99%) that is ≥ 60%. From the obtained results, the best yield percentage was obtained using K2CO3 catalyst from cacao pod husk extract, i.e. 73-85%. To cope with biodiesel conversion efficiency, a two-step process consisting pretreatment with activated carbon carbonized at 350°C and esterification with K2CO3 from cocoa pod husk catalyst was developed. This two-step process could reach a high conversion of 85%. From the results it was clear that the produced

Carbon Nanotube Templated Microfabrication of Porous Silicon-Carbon Materials

Science.gov (United States)

Song, Jun; Jensen, David; Dadson, Andrew; Vail, Michael; Linford, Matthew; Vanfleet, Richard; Davis, Robert

2010-10-01

Carbon nanotube templated microfabrication (CNT-M) of porous materials is demonstrated. Partial chemical infiltration of three dimensional carbon nanotube structures with silicon resulted in a mechanically robust material, precisely structured from the 10 nm scale to the 100 micron scale. Nanoscale dimensions are determined by the diameter and spacing of the resulting silicon/carbon nanotubes while the microscale dimensions are controlled by lithographic patterning of the CNT growth catalyst. We demonstrate the utility of this hierarchical structuring approach by using CNT-M to fabricate thin layer chromatography (TLC) separations media with precise microscale channels for fluid flow control and nanoscale porosity for high analyte capacity.

Development of a Method to Isolate Glutamic Acid from Foodstuffs for a Precise Determination of Their Stable Carbon Isotope Ratio.

Science.gov (United States)

Kobayashi, Kazuhiro; Tanaka, Masaharu; Yatsukawa, Yoichi; Tanabe, Soichi; Tanaka, Mitsuru; Ohkouchi, Naohiko

2018-01-01

Recent growing health awareness is leading to increasingly conscious decisions by consumers regarding the production and traceability of food. Stable isotopic compositions provide useful information for tracing the origin of foodstuffs and processes of food production. Plants exhibit different ratios of stable carbon isotopes (δ 13 C) because they utilized different photosynthetic (carbon fixation) pathways and grow in various environments. The origins of glutamic acid in foodstuffs can be differentiated on the basis of these photosynthetic characteristics. Here, we have developed a method to isolate glutamic acid in foodstuffs for determining the δ 13 C value by elemental analyzer-isotope-ratio mass spectrometry (EA/IRMS) without unintended isotopic fractionation. Briefly, following acid-hydrolysis, samples were defatted and passed through activated carbon and a cation-exchange column. Then, glutamic acid was isolated using preparative HPLC. This method is applicable to measuring, with a low standard deviation, the δ 13 C values of glutamic acid from foodstuffs derived from C3 and C4 plants and marine algae.

Molecular Basis of Microbial One-Carbon Metabolism 2008 Gordon Research Conference (July 20-25, 2008)

Energy Technology Data Exchange (ETDEWEB)

Stephen W. Ragsdale

2009-08-12

One-carbon (C-1) compounds play a central role in microbial metabolism. C-1 compounds include methane, carbon monoxide, CO2, and methanol as well as coenzyme-bound one-carbon compounds (methyl-B12, CH3-H4folate, etc). Such compounds are of broad global importance because several C-1 compounds (e.g., CH4) are important energy sources, some (e.g., CO2 and CH4) are potent greenhouse gases, and others (e.g., CH2Cl2) are xenobiotics. They are central in pathways of energy metabolism and carbon fixation by microbes and many are of industrial interest. Research on the pathways of one-carbon metabolism has added greatly to our understanding of evolution, structural biology, enzyme mechanisms, gene regulation, ecology, and applied biology. The 2008 meeting will include recent important findings in the following areas: (a) genomics, metagenomics, and proteomic studies that have expanded our understanding of autotrophy and C-1 metabolism and the evolution of these pathways; (b) redox regulation of carbon cycles and the interrelationship between the carbon cycle and other biogeochemical cycles (sulfur, nitrogen, oxygen); (c) novel pathways for carbon assimilation; (d) biotechnology related to C-1 metabolism; (e) novel enzyme mechanisms including channeling of C-1 intermediates during metabolism; and (f) the relationship between metal homeostasis and the global carbon cycle. The conference has a diverse and gender-balanced slate of speakers and session leaders. The wide variety of disciplines brought to the study of C-1 metabolism make the field an excellent one in which to train young researchers.

In Silico Analysis of Putrefaction Pathways in Bacteria and Its Implication in Colorectal Cancer

Directory of Open Access Journals (Sweden)

Harrisham Kaur

2017-11-01

Full Text Available Fermentation of undigested proteins in human gastrointestinal tract (gut by the resident microbiota, a process called bacterial putrefaction, can sometimes disrupt the gut homeostasis. In this process, essential amino acids (e.g., histidine, tryptophan, etc. that are required by the host may be utilized by the gut microbes. In addition, some of the products of putrefaction, like ammonia, putrescine, cresol, indole, phenol, etc., have been implicated in the disease pathogenesis of colorectal cancer (CRC. We have investigated bacterial putrefaction pathways that are known to be associated with such metabolites. Results of the comprehensive in silico analysis of the selected putrefaction pathways across bacterial genomes revealed presence of these pathways in limited bacterial groups. Majority of these bacteria are commonly found in human gut. These include Bacillus, Clostridium, Enterobacter, Escherichia, Fusobacterium, Salmonella, etc. Interestingly, while pathogens utilize almost all the analyzed pathways, commensals prefer putrescine and H2S production pathways for metabolizing the undigested proteins. Further, comparison of the putrefaction pathways in the gut microbiomes of healthy, carcinoma and adenoma datasets indicate higher abundances of putrefying bacteria in the carcinoma stage of CRC. The insights obtained from the present study indicate utilization of possible microbiome-based therapies to minimize the adverse effects of gut microbiome in enteric diseases.

Efficiency and CO[sub 2] emission analysis of pathways by which methane can provide transportation services

Energy Technology Data Exchange (ETDEWEB)

Crane, P; Scott, D S [Victoria Univ., BC (Canada). Inst. for Integrated Energy Systems Victoria Univ., BC (Canada). Dept. of Mechanical Engineering

1992-07-01

Methane is expected to have an increasingly important role as an energy source in the future. As a result, methane will become a major energy source for the transportation sector. Future energy systems will also be selected for efficiency and environmental gentility. Six candidate pathways by which the energy for service transportation can be provided, using methane as the sole energy source, are proposed and are compared with the use of gasoline from petroleum. These pathways involve methanol, methane and hydrogen used in spark ignition engines and solid polymer fuel cells. The energy conversion processes in each pathway are analysed based on the second law of thermodynamics. Two performance criteria are used: total exergy input to the pathway and total carbon dioxide produced along the pathway. All results are normalized to a unit of transportation service, in this case 1 km of city driving. A surprising result is that the methanol spark ignition engine pathway is the least efficient and produces the greatest amount of carbon dioxide, of the pathways examined. Hydrogen and fuel cell pathways are found to be optimal using the criteria of this paper. (author)

Combination of Asymmetric Supercapacitor Utilizing Activated Carbon and Nickel Oxide with Cobalt Polypyridyl-Based Dye-Sensitized Solar Cell

International Nuclear Information System (INIS)

Bagheri, Narjes; Aghaei, Alireza; Ghotbi, Mohammad Yeganeh; Marzbanrad, Ehsan; Vlachopoulos, Nick; Häggman, Leif; Wang, Michael; Boschloo, Gerrit; Hagfeldt, Anders; Skunik-Nuckowska, Magdalena; Kulesza, Pawel J.

2014-01-01

Highlights: • Dye Solar Cell and supercapacitor are integrated into a single device capable of generation and storage of energy. • The solar cell part of the device utilizes the Co-based electrolyte and nickel/PEDOT counter electrode. • A cobalt-doped nickel oxide together with activated carbon is used in the capacitor part of the device. • The integrated photocapacitor is characterized by the capacitance of 32 F g −1 and the total efficiency of 0.6%. - Abstract: A dye-sensitized solar cell (DSC) based on the metal-free organic sensitizer and the cobalt (II, III) polypyridyl electrolyte was integrated here within an asymmetric supercapacitor utilizing cobalt-doped nickel oxide and activated carbon as positive and negative electrodes, respectively. A low cost nickel foil served as intermediate (auxiliary) bifunctional electrode separating two parts of the device and permitting the DSC electrolyte regeneration at one side and charge storage within cobalt-doped nickel oxide at the other. The main purpose of the research was to develop an integrated photocapacitor system capable of both energy generation and its further storage. Following irradiation at the 100 mW cm −2 level, the solar cell generated an open-circuit voltage of 0.8 V and short-circuit current of 8 mA cm −2 which corresponds to energy conversion efficiency of 4.9%. It was further shown that upon integration with asymmetric supercapacitor, the photogenerated energy was directly injected into porous charge storage electrodes thus resulting in specific capacitance of 32 F g −1 and energy density of 2.3 Wh kg −1 . The coulumbic and total (energy conversion and charge storage) efficiency of photocapacitor were equal to 54% and 0.6%, respectively

Improved tensile and buckling behavior of defected carbon nanotubes utilizing boron nitride coating – A molecular dynamic study

Energy Technology Data Exchange (ETDEWEB)

Badjian, H.; Setoodeh, A.R., E-mail: setoodeh@sutech.ac.ir

2017-02-15

Synthesizing inorganic nanostructures such as boron nitride nanotubes (BNNTs) have led to immense studies due to their many interesting functional features such as piezoelectricity, high temperature resistance to oxygen, electrical insulation, high thermal conductivity and very long lengths as physical features. In order to utilize the superior properties of pristine and defected carbon nanotubes (CNTs), a hybrid nanotube is proposed in this study by forming BNNTs surface coating on the CNTs. The benefits of such coating on the tensile and buckling behavior of single-walled CNTs (SWCNTs) are illustrated through molecular dynamics (MD) simulations of the resulted nanostructures during the deformation. The AIREBO and Tersoff-Brenner potentials are employed to model the interatomic forces between the carbon and boron nitride atoms, respectively. The effects of chiral indices, aspect ratio, presence of mono-vacancy defects and coating dimension on coated/non-coated CNTs are examined. It is demonstrated that the coated defective CNTs exhibit remarkably enhanced ultimate strength, buckling load capacity and Young's modulus. The proposed coating not only enhances the mechanical properties of the resulted nanostructure, but also conceals it from few external factors impacting the behavior of the CNT such as humidity and high temperature.

Pathways to deep decarbonization - Interim 2014 Report

International Nuclear Information System (INIS)

2014-01-01

The interim 2014 report by the Deep Decarbonization Pathways Project (DDPP), coordinated and published by IDDRI and the Sustainable Development Solutions Network (SDSN), presents preliminary findings of the pathways developed by the DDPP Country Research Teams with the objective of achieving emission reductions consistent with limiting global warming to less than 2 deg. C. The DDPP is a knowledge network comprising 15 Country Research Teams and several Partner Organizations who develop and share methods, assumptions, and findings related to deep decarbonization. Each DDPP Country Research Team has developed an illustrative road-map for the transition to a low-carbon economy, with the intent of taking into account national socio-economic conditions, development aspirations, infrastructure stocks, resource endowments, and other relevant factors. The interim 2014 report focuses on technically feasible pathways to deep decarbonization

Possible Roles of Fluoride and Carbonate in Biochemical Carbonated Apatite Formation

Science.gov (United States)

Meouch, Orysia; Omelon, Sidney

2016-04-01

Marine phosphorites are predominantly composed of carbonated fluorapatite (CFA = Ca10-a-b-cNaaMgb(PO4)6-x(CO3)x-y-z(CO3.F)y(SO4)zF2, where x=y+a+2c, and c represents the number of Ca vacancies, with a P2O5 content that ranges from 18-40 %. Sulphur-oxidizing bacteria of the Beggiatoa genus concentration phosphorous as intracellular polyphosphate ((PO3-)n) which is depolymerized into inorganic orthophosphate (Pi). Consequently, an increase in pore water Pi concentration favours carbonated apatite precipitation. The carbonate and fluoride that is characteristic of phosphorite CFA is also located in the vertebrate skeleton. This similarity suggests a biochemical pathway for CFA precipitation. Preliminary Raman spectroscopy and powder x-ray diffraction results that suggest a role for fluoride, and possibly carbonate, in the biochemical depolymerisation of polyphosphates with alkaline phosphatase will be presented.

Conservation of PHO pathway in ascomycetes and the role of Pho84

Indian Academy of Sciences (India)

In budding yeast, Saccharomyces cerevisiae, the phosphate signalling and response pathway, known as PHO pathway, monitors phosphate cytoplasmic levels by controlling genes involved in scavenging, uptake and utilization of phosphate. Recent attempts to understand the phosphate starvation response in other ...

Microbial utilization of low molecular weight organic substrates in soil depends on their carbon oxidation state

Science.gov (United States)

Gunina, Anna; Smith, Andrew; Jones, Davey; Kuzyakov, Yakov

2017-04-01

Removal of low molecular weight organic substances (LMWOS), originating from plants and microorganisms, from soil solution is regulated by microbial uptake. In addition to the concentration of LMWOS in soil solution, the chemical properties of each substance (e.g. C oxidation state, number of C atoms, number of -COOH groups) can affect their uptake and subsequent partitioning of C within the soil microbial community. The aim of this study was to trace the initial fate of three dominant classes of LMWOS in soil (sugars, carboxylic and amino acids), including their removal from solution and utilization by microorganisms, and to reveal the effect of substance chemical properties on these processes. Soil solution, spiked at natural abundance levels with 14C-labelled glucose, fructose, malate, succinate, formate, alanine or glycine, was added to the soil and 14C was traced in the dissolved organic carbon (DOC), CO2, cytosol and soil organic carbon (SOC) over 24 hours. The half-life time of all LMWOS in the DOC (T1 /2-solution) varied between 0.6-5.0 min showing extremely fast initial uptake of LMWOS. The T1 /2-solution of substances was dependent on C oxidation state, indicating that less oxidized organic substances (with C oxidation state "0") were retained longer in soil solution than oxidized substances. The LMWOS-C T1 /2-fast, characterizing the half-life time of 14C in the fast mineralization pool, ranged between 30 and 80 min, with the T1 /2-fast of carboxylic acids (malic acid) being the fastest and the T1 /2-fast of amino acids (glycine) being the slowest. An absence of correlation between T1 /2-fast and either C oxidation state, number of C atoms, or number of -COOH groups suggests that intercellular metabolic pathways are more important for LMWOS transformation in soil than their basic chemical properties. The CO2 release during LMWOS mineralization accounted for 20-90% of 14C applied. Mineralization of LMWOS was the least for sugars and the greatest for

Molecular dynamics simulation of carbon nanostructures: The C60 buckminsterfullerene

International Nuclear Information System (INIS)

Laszlo, Istvan; Zsoldos, Ibolya

2012-01-01

Molecular dynamics calculations can reveal the physical and chemical properties of various carbon nanostructures or can help to devise the possible formation pathways. In our days the most well-known carbon nanostructures are the fullerenes, the nanotubes, and the graphene. The fullerenes and nanotubes can be thought of as being formed from graphene sheets, i.e., single layers of carbon atoms arranged in a honeycomb lattice. Usually the nature does not follow the mathematical constructions. Although the first time the C 60 and the C 70 were produced by laser irradiated graphite, the fullerene formation theories are based on various fragments of carbon chains and networks of pentagonal and hexagonal rings. In the present article various formation pathways for the buckminsterfullerene C 60 molecule will be presented. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Following Carbon Isotopes from Methane to Molecules

Science.gov (United States)

Freeman, K. H.

2017-12-01

Continuous-flow methods introduced by Hayes (Matthews and Hayes, 1978; Freeman et al., 1990; Hayes et al., 1990) for compound-specific isotope analyses (CSIA) transformed how we study the origins and fates of organic compounds. This analytical revolution launched several decades of research in which researchers connect individual molecular structures to diverse environmental and climate processes affecting their isotopic profiles. Among the first applications, and one of the more dramatic isotopically, was tracing the flow of natural methane into cellular carbon and cellular biochemical constituents. Microbial oxidation of methane can be tracked by strongly 13C-depleted organic carbon in early Earth sedimentary environments, in marine and lake-derived biomarkers in oils, and in modern organisms and their environments. These signatures constrain microbial carbon cycling and inform our understanding of ocean redox. The measurement of molecular isotopes has jumped forward once again, and it is now possible to determine isotope abundances at specific positions within increasingly complex organic structures. In addition, recent analytical developments have lowered sample sensitivity limits of CSIA to picomole levels. These new tools have opened new ways to measure methane carbon in the natural environment and within biochemical pathways. This talk will highlight how molecular isotope methods enable us to follow the fate of methane carbon in complex environments and along diverse metabolic pathways, from trace fluids to specific carbon positions within microbial biomarkers.

Renewable energy and low carbon economy transition in India

DEFF Research Database (Denmark)

Shukla, P.R.; Dhar, Subash; Fujino, Junichi

2010-01-01

that aligns India’s emissions to an optimal 450 ppmv CO2-eq. stabilization global response. The second emissions pathway assumes an underlying sustainable development pattern. A low carbon future will be good for renewable energy under both the development pathways, though the share of renewable energy...

The Aedes aegypti toll pathway controls dengue virus infection.

Directory of Open Access Journals (Sweden)

Zhiyong Xi

2008-07-01

Full Text Available Aedes aegypti, the mosquito vector of dengue viruses, utilizes its innate immune system to ward off a variety of pathogens, some of which can cause disease in humans. To date, the features of insects' innate immune defenses against viruses have mainly been studied in the fruit fly Drosophila melanogaster, which appears to utilize different immune pathways against different types of viruses, in addition to an RNA interference-based defense system. We have used the recently released whole-genome sequence of the Ae. aegypti mosquito, in combination with high-throughput gene expression and RNA interference (RNAi-based reverse genetic analyses, to characterize its response to dengue virus infection in different body compartments. We have further addressed the impact of the mosquito's endogenous microbial flora on virus infection. Our findings indicate a significant role for the Toll pathway in regulating resistance to dengue virus, as indicated by an infection-responsive regulation and functional assessment of several Toll pathway-associated genes. We have also shown that the mosquito's natural microbiota play a role in modulating the dengue virus infection, possibly through basal-level stimulation of the Toll immune pathway.

The diversification value of nuclear power as part of a utility technology mix when gas and carbon prices are uncertain

International Nuclear Information System (INIS)

Roques, Fabien A.; Nuttall, William J.; Newbery, David M.; Neufville, Richard de; Connors, Stephen

2005-01-01

Despite recent revived interest, the prospects for new nuclear power investment in liberalized electricity industries without government support do not seem promising. The objective of this paper is twofold. First it aims to identify the specific features of nuclear power technology that makes it an unattractive choice. The second objective is to estimate the value to a utility of a nuclear investment as a hedge against uncertain gas and carbon prices. A stylized 5-plant Real Option utility model shows that while the nuclear option value represents about 18% of the net present value (NPV) of the nuclear plant investment in the case where electricity and gas prices are uncorrelated, it reduces to nearly zero for correlation factors between electricity and gas price greater than 30%. These results suggest that the private diversification incentives in electricity markets might not be aligned with the social value of a diverse fuel-mix at the country level. (Author)

Nitrogen-fixing methane-utilizing bacteria

NARCIS (Netherlands)

Bont, de J.A.M.

1976-01-01

Methane occurs abundantly in nature. In the presence of oxygen this gas may be metabolized by bacteria that are able to use it as carbon and energy source. Several types of bacteria involved in the oxidation of methane have been described in literature. Methane-utilizing bacteria have in

Corn cob biochar increases soil culturable bacterial abundance without enhancing their capacities in utilizing carbon sources in Biolog Eco-plates

Institute of Scientific and Technical Information of China (English)

JIANG Lin-lin; HAN Guang-ming; LAN Yu; LIU Sai-nan; GAO Ji-ping; YANG Xu; MENG Jun; CHEN Wen-fu

2017-01-01

Biochar has been shown to influence soil microbial communities in terms of their abundance and diversity.However,the relationship among microbial abundance,structure and C metabolic traits is not well studied under biochar application.Here it was hypothesized that the addition of biochar with intrinsic properties (i.e.,porous structure) could affect the proliferation of culturable microbes and the genetic structure of soil bacterial communities.In the meantime,the presence of available organic carbon in biochar may influence the C utilization capacities of microbial community in Biolog Eco-plates.A pot experiment was conducted with differenct biochar application (BC) rates:control (0 t ha-1),BC1 (20 t ha-1) and BC2 (40 t ha-1).Culturable microorganisms were enumerated via the plate counting method.Bacterial diversity was examined using denaturing gradient gel electrophoresis (DGGE).Microbial capacity in using C sources was assessed using Biolog Eco-plates.The addition of biochar stimulated the growth of actinomyces and bacteria,especially the ammonifying bacteria and azotobacteria,but had no significant effect on fungi proliferation.The phylogenetic distribution of the operational taxonomic units could be divided into the following groups with the biochar addition:Firmicutes,Acidobacteria,Gemmatimonadetes,Actinobacteria,Cyanobacteria and α-,β-,γ-and δ-Proteobacteria (average similarity ＞95％).Biochar application had a higher capacity utilization for L-asparagine,Tween 80,D-mannitol,L-serine,γ-hydroxybutyric acid,N-acetyI-D-glucosamine,glycogen,itaconic acid,glycyl-L-glutamic acid,α-ketobutyricacid and putrescine,whereas it had received decreased capacities in using the other 20 carbon sources in Biolog Eco-plates.Redundancy analysis (RDA) revealed that the physico-chemical properties,indices of bacterial diversity,and C metabolic traits were positively correlated with the appearance of novel sequences under BC2 treatment.Our study indicates that the

Improved fermentative L-cysteine overproduction by enhancing a newly identified thiosulfate assimilation pathway in Escherichia coli.

Science.gov (United States)

Kawano, Yusuke; Onishi, Fumito; Shiroyama, Maeka; Miura, Masashi; Tanaka, Naoyuki; Oshiro, Satoshi; Nonaka, Gen; Nakanishi, Tsuyoshi; Ohtsu, Iwao

2017-09-01

Sulfate (SO 4 2- ) is an often-utilized and well-understood inorganic sulfur source in microorganism culture. Recently, another inorganic sulfur source, thiosulfate (S 2 O 3 2- ), was proposed to be more advantageous in microbial growth and biotechnological applications. Although its assimilation pathway is known to depend on O-acetyl-L-serine sulfhydrylase B (CysM in Escherichia coli), its metabolism has not been extensively investigated. Therefore, we aimed to explore another yet-unidentified CysM-independent thiosulfate assimilation pathway in E. coli. ΔcysM cells could accumulate essential L-cysteine from thiosulfate as the sole sulfur source and could grow, albeit slowly, demonstrating that a CysM-independent thiosulfate assimilation pathway is present in E. coli. This pathway is expected to consist of the initial part of the thiosulfate to sulfite (SO 3 2- ) conversion, and the latter part might be shared with the final part of the known sulfate assimilation pathway [sulfite → sulfide (S 2- ) → L-cysteine]. This is because thiosulfate-grown ΔcysM cells could accumulate a level of sulfite and sulfide equivalent to that of wild-type cells. The catalysis of thiosulfate to sulfite is at least partly mediated by thiosulfate sulfurtransferase (GlpE), because its overexpression could enhance cellular thiosulfate sulfurtransferase activity in vitro and complement the slow-growth phenotype of thiosulfate-grown ΔcysM cells in vivo. GlpE is therefore concluded to function in the novel CysM-independent thiosulfate assimilation pathway by catalyzing thiosulfate to sulfite. We applied this insight to L-cysteine overproduction in E. coli and succeeded in enhancing it by GlpE overexpression in media containing glucose or glycerol as the main carbon source, by up to ~1.7-fold (1207 mg/l) or ~1.5-fold (1529 mg/l), respectively.

Life Cycle Greenhouse Gas Analysis of Multiple Vehicle Fuel Pathways in China

Directory of Open Access Journals (Sweden)

Tianduo Peng

2017-11-01

Full Text Available The Tsinghua University Life Cycle Analysis Model (TLCAM is applied to calculate the life cycle fossil energy consumption and greenhouse gas (GHG emissions for more than 20 vehicle fuel pathways in China. In addition to conventional gasoline and diesel, these include coal- and gas-based vehicle fuels, and electric vehicle (EV pathways. The results indicate the following. (1 China’s current dependence on coal and relative low-efficiency processes limits the potential for most alternative fuel pathways to decrease energy consumption and emissions; (2 Future low-carbon electricity pathways offer more obvious advantages, with coal-based pathways needing to adopt carbon dioxide capture and storage technology to compete; (3 A well-to-wheels analysis of the fossil energy consumption of vehicles fueled by compressed natural gas and liquefied natural gas (LNG showed that they are comparable to conventional gasoline vehicles. However, importing rather than domestically producing LNG for vehicle use can decrease domestic GHG emissions by 35% and 31% compared with those of conventional gasoline and diesel vehicles, respectively; (4 The manufacturing and recovery of battery and vehicle in the EV analysis has significant impact on the overall ability of EVs to decrease fossil energy consumption and GHG emissions from ICEVs.

Technique for production of graphite-carbon products

Energy Technology Data Exchange (ETDEWEB)

Antonov, A.N.; Bentsianovskaya, I.A.; Filatova, V.A.; Nabokov, V.S.; Nestor, V.P.; Zil' bergleyt, I.M.

1982-01-01

The technique for producing carbon-graphite products that includes filtration under a pressure of 0.1-015 MPa (through graphite stock) of an aqueous carbon material with the addition of surfactant, drying, and subsequent thermal treatment, is simplified and made less lengthy. Oxidized graphite is utilized with a prior addition of 1-10% water-soluble organic substance into the suspension -molasses, hemicellulose, sugar or polyacrylamide. A 0.03-1.5% suspension of oxidized graphite is utilized, with a particle size of 0.02-0.1 mkm. Thermal processing is done in a carbon fill, at a rate of 10-20 degrees/hour to 700-800/sup 0/, maintained 2-3 hours.

Fly ashes from Polish power plants and combined heat and power plants and conditions of their application for carbon dioxide utilization

Energy Technology Data Exchange (ETDEWEB)

Uliasz-Bochenczyk, A.; Mokrzycki, E. [Polish Academy of Science, Krakow (Poland). Mineral & Energy Economic Research Institute

2006-09-15

Poland has large resources of hard coal and brown coal. Therefore power industry is mostly based on these two original energy carriers. The power plants producing heat and electrical energy create combustion byproducts. These products include: fly ashes, slags, carbon dioxide and other gaseous compounds. In year 2003 fly ashes emission from hard coal combustion in Poland reached 37 000 tons and over 15 000 tons from brown coal combustion. Fly ashes are widely used in the economy. They are used in building materials industry, in road building and geotechnics. CO{sub 2} emission in Poland in 2003 originating from hard coal combustion was almost 91 million tons and from brown coal combustion-almost 58 million tons. High emissions of CO{sub 2} originating from power engineering processes of coal combustion are deleterious to the natural environment, contributing to the greenhouse effect. Presently there are carried out studies aimed at limiting CO{sub 2} emission coming from industrial processes. Fly ash properties are determined by qualitative characteristics of combusted coal, its chemical composition and combustion technology. Chemical composition of Polish fly ashes is very diversified. Fly ashes with high calcium oxide content can be used for carbon dioxide fixation. Fly ash carbonation is a complicated process however safe for natural environment. Polish fly ashes coming from power engineering, conditions of their use for the carbon dioxide utilization as well as their quantitative and qualitative characteristics are the subjects of this paper.

Carbon Dioxide Emission Pathways Avoiding Dangerous Ocean Impacts

OpenAIRE

Kvale, K.; Zickfeld, K.; Bruckner, T.; Meissner, K. J.; Tanaka, K.; Weaver, A. J.

2012-01-01

Anthropogenic emissions of greenhouse gases could lead to undesirable effects on oceans in coming centuries. Drawing on recommendations published by the German Advisory Council on Global Change, levels of unacceptable global marine change (so-called guardrails) are defined in terms of global mean temperature, sea level rise, and ocean acidification. A global-mean climate model [the Aggregated Carbon Cycle, Atmospheric Chemistry and Climate Model (ACC2)] is coupled with an economic module [tak...

Principles of Carbon Catabolite Repression in the Rice Blast Fungus: Tps1, Nmr1-3, and a MATE–Family Pump Regulate Glucose Metabolism during Infection

Science.gov (United States)

Hartline, David; Quispe, Cristian F.; Madayiputhiya, Nandakumar; Wilson, Richard A.

2012-01-01

Understanding the genetic pathways that regulate how pathogenic fungi respond to their environment is paramount to developing effective mitigation strategies against disease. Carbon catabolite repression (CCR) is a global regulatory mechanism found in a wide range of microbial organisms that ensures the preferential utilization of glucose over less favourable carbon sources, but little is known about the components of CCR in filamentous fungi. Here we report three new mediators of CCR in the devastating rice blast fungus Magnaporthe oryzae: the sugar sensor Tps1, the Nmr1-3 inhibitor proteins, and the multidrug and toxin extrusion (MATE)–family pump, Mdt1. Using simple plate tests coupled with transcriptional analysis, we show that Tps1, in response to glucose-6-phosphate sensing, triggers CCR via the inactivation of Nmr1-3. In addition, by dissecting the CCR pathway using Agrobacterium tumefaciens-mediated mutagenesis, we also show that Mdt1 is an additional and previously unknown regulator of glucose metabolism. Mdt1 regulates glucose assimilation downstream of Tps1 and is necessary for nutrient utilization, sporulation, and pathogenicity. This is the first functional characterization of a MATE–family protein in filamentous fungi and the first description of a MATE protein in genetic regulation or plant pathogenicity. Perturbing CCR in Δtps1 and MDT1 disruption strains thus results in physiological defects that impact pathogenesis, possibly through the early expression of cell wall–degrading enzymes. Taken together, the importance of discovering three new regulators of carbon metabolism lies in understanding how M. oryzae and other pathogenic fungi respond to nutrient availability and control development during infection. PMID:22570632

Construction of cellulose-utilizing Escherichia coli based on a secretable cellulase.

Science.gov (United States)

Gao, Dongfang; Luan, Yaqi; Wang, Qian; Liang, Quanfeng; Qi, Qingsheng

2015-10-09

The microbial conversion of plant biomass into value added products is an attractive option to address the impacts of petroleum dependency. The Gram-negative bacterium Escherichia coli is commonly used as host for the industrial production of various chemical products with a variety of sugars as carbon sources. However, this strain neither produces endogenous cellulose degradation enzymes nor secrets heterologous cellulases for its poor secretory capacity. Thus, a cellulolytic E. coli strain capable of growth on plant biomass would be the first step towards producing chemicals and fuels. We previously identified the catalytic domain of a cellulase (Cel-CD) and its N-terminal sequence (N20) that can serve as carriers for the efficient extracellular production of target enzymes. This finding suggested that cellulose-utilizing E. coli can be engineered with minimal heterologous enzymes. In this study, a β-glucosidase (Tfu0937) was fused to Cel-CD and its N-terminal sequence respectively to obtain E. coli strains that were able to hydrolyze the cellulose. Recombinant strains were confirmed to use the amorphous cellulose as well as cellobiose as the sole carbon source for growth. Furthermore, both strains were engineered with poly (3-hydroxybutyrate) (PHB) synthesis pathway to demonstrate the production of biodegradable polyesters directly from cellulose materials without exogenously added cellulases. The yield of PHB reached 2.57-8.23 wt% content of cell dry weight directly from amorphous cellulose/cellobiose. Moreover, we found the Cel-CD and N20 secretion system can also be used for the extracellular production of other hydrolytic enzymes. This study suggested that a cellulose-utilizing E. coli was created based on a heterologous cellulase secretion system and can be used to produce biofuels and biochemicals directly from cellulose. This system also offers a platform for conversion of other abundant renewable biomass to biofuels and biorefinery products.

Rule Mining Techniques to Predict Prokaryotic Metabolic Pathways

KAUST Repository

Saidi, Rabie

2017-08-28

It is becoming more evident that computational methods are needed for the identification and the mapping of pathways in new genomes. We introduce an automatic annotation system (ARBA4Path Association Rule-Based Annotator for Pathways) that utilizes rule mining techniques to predict metabolic pathways across wide range of prokaryotes. It was demonstrated that specific combinations of protein domains (recorded in our rules) strongly determine pathways in which proteins are involved and thus provide information that let us very accurately assign pathway membership (with precision of 0.999 and recall of 0.966) to proteins of a given prokaryotic taxon. Our system can be used to enhance the quality of automatically generated annotations as well as annotating proteins with unknown function. The prediction models are represented in the form of human-readable rules, and they can be used effectively to add absent pathway information to many proteins in UniProtKB/TrEMBL database.

Rule Mining Techniques to Predict Prokaryotic Metabolic Pathways

KAUST Repository

Saidi, Rabie; Boudellioua, Imene; Martin, Maria J.; Solovyev, Victor

2017-01-01

It is becoming more evident that computational methods are needed for the identification and the mapping of pathways in new genomes. We introduce an automatic annotation system (ARBA4Path Association Rule-Based Annotator for Pathways) that utilizes rule mining techniques to predict metabolic pathways across wide range of prokaryotes. It was demonstrated that specific combinations of protein domains (recorded in our rules) strongly determine pathways in which proteins are involved and thus provide information that let us very accurately assign pathway membership (with precision of 0.999 and recall of 0.966) to proteins of a given prokaryotic taxon. Our system can be used to enhance the quality of automatically generated annotations as well as annotating proteins with unknown function. The prediction models are represented in the form of human-readable rules, and they can be used effectively to add absent pathway information to many proteins in UniProtKB/TrEMBL database.

Carbon flows through a benthic food web: Integrating biomass, isotope and tracer data

NARCIS (Netherlands)

Van Oevelen, D.; Soetaert, K.E.R.; Middelburg, J.J.; Herman, P.M.J.; Moodley, L.; Hamels, I.; Moens, T.; Heip, C.H.R.

2006-01-01

The herbivorous, detrital and microbial pathways are major components of marine food webs. Although it is commonly recognized that these pathways can be linked in several ways, elucidating carbon transfers between or within these pathways remains a challenge. Intertidal flat communities are driven

Energy consumption and GHG emissions of six biofuel pathways by LCA in China

Energy Technology Data Exchange (ETDEWEB)

Ou, Xunmin [School of Public Policy and Management (SPPM), Tsinghua University, Beijing 100084 (China); China Automotive Energy Research Center (CAERC), Tsinghua University, Beijing 100084 (China); Institute of Energy, Environment and Economy (3E), Tsinghua University, Beijing 100084 (China); Zhang, Xiliang; Chang, Shiyan; Guo, Qingfang [China Automotive Energy Research Center (CAERC), Tsinghua University, Beijing 100084 (China); Institute of Energy, Environment and Economy (3E), Tsinghua University, Beijing 100084 (China)

2009-11-15

This paper presents life-cycle-analysis (LCA) energy consumption (EC) and greenhouse gas (GHG) emissions of China's current six biofuel pathways, which are: corn-derived ethanol (CE); cassava-derived ethanol (KE); sweet sorghum-derived ethanol (SE); soybean-derived bio-diesel (SB); jatropha fruit-derived bio-diesel (JB); and used cooking oil (UCO)-derived bio-diesel (UB). The tool utilized here is the WTW (Well-to-Wheels) module of Tsinghua-CA3EM model covering the entire lifecycle including: raw materials cultivation (or feedstock collection); fuel production; transportation and distribution; and application in automobile engines, compared with Conventional Petroleum-based gasoline and diesel Pathways (CPP). The results indicate: (1) the fossil energy inputs are about 1.0-1.5 times the energy contained in the fuel for the CE, SE and SB pathways, but 0.5-0.9 times for the KE, UB and JB pathways; (2) compared with CPP, the JB, KE and UB pathways can reduce both fossil fuel consumption and GHG emissions; the CE and SB pathways can only reduce fossil fuel consumption, but increase GHG emission; the SE pathway increases not only fossil fuel consumption but also GHG emission; and (3) the main factors inducing high EC and GHG emission levels include: high EC levels during the fuel production stage and high fertilizer application rates during the planting of raw feedstocks. Conclusions are that of the aforementioned biofuel pathways in China: (1) only the JB, KE and UB pathways have energy-saving merits as indicated by the LCA energy inputs and outputs; (2) compared with CPP, all but the SE pathway reduces fossil fuel consumption. However, the SB and CE pathway increase GHG emission; (3) all six displace petroleum by utilizing more coal; and (4) feedstock productivity levels must be increased, and there must be a reduction in fertilizer utilization and EC consumption during the cultivation and transportation stages in order to achieve the goals of energy balance and

Energy consumption and GHG emissions of six biofuel pathways by LCA in China

International Nuclear Information System (INIS)

Ou Xunmin; Zhang Xiliang; Chang Shiyan; Guo Qingfang

2009-01-01

This paper presents life-cycle-analysis (LCA) energy consumption (EC) and greenhouse gas (GHG) emissions of China's current six biofuel pathways, which are: corn-derived ethanol (CE); cassava-derived ethanol (KE); sweet sorghum-derived ethanol (SE); soybean-derived bio-diesel (SB); jatropha fruit-derived bio-diesel (JB); and used cooking oil (UCO)-derived bio-diesel (UB). The tool utilized here is the WTW (Well-to-Wheels) module of Tsinghua-CA3EM model covering the entire lifecycle including: raw materials cultivation (or feedstock collection); fuel production; transportation and distribution; and application in automobile engines, compared with Conventional Petroleum-based gasoline and diesel Pathways (CPP). The results indicate: (1) the fossil energy inputs are about 1.0-1.5 times the energy contained in the fuel for the CE, SE and SB pathways, but 0.5-0.9 times for the KE, UB and JB pathways; (2) compared with CPP, the JB, KE and UB pathways can reduce both fossil fuel consumption and GHG emissions; the CE and SB pathways can only reduce fossil fuel consumption, but increase GHG emission; the SE pathway increases not only fossil fuel consumption but also GHG emission; and (3) the main factors inducing high EC and GHG emission levels include: high EC levels during the fuel production stage and high fertilizer application rates during the planting of raw feedstocks. Conclusions are that of the aforementioned biofuel pathways in China: (1) only the JB, KE and UB pathways have energy-saving merits as indicated by the LCA energy inputs and outputs; (2) compared with CPP, all but the SE pathway reduces fossil fuel consumption. However, the SB and CE pathway increase GHG emission; (3) all six displace petroleum by utilizing more coal; and (4) feedstock productivity levels must be increased, and there must be a reduction in fertilizer utilization and EC consumption during the cultivation and transportation stages in order to achieve the goals of energy balance and GHG

Identification of the Entner-Doudoroff pathway in an antibiotic-producing actinomycete species

DEFF Research Database (Denmark)

Gunnarsson, Nina; Mortensen, Uffe Hasbro; Sosio, M.

2004-01-01

the primary metabolic pathways of the poorly characterized antibiotic-producing actinomycete Nonomuraea sp. ATCC 39727. Surprisingly, it was found that Nonomuraea sp. ATCC 39272 predominantly metabolizes glucose via the Entner-Doudoroff (ED) pathway. This represents the first time that the ED pathway has been...... to design metabolic engineering strategies towards construction of more efficient producers of specific metabolites. In this context, methods that allow rapid and reliable mapping of the central carbon metabolism are valuable. In the present study, a C-13 labelling-based method was used to identify...... recognized as the main catabolic pathway in an actinomycete. The Nonomuraea genes encoding the key enzymes of the ED pathway were subsequently identified, sequenced and functionally described....

Carbon dioxide (CO 2 ) utilizing strain database | Saini | African ...

African Journals Online (AJOL)

Culling of excess carbon dioxide from our environment is one of the major challenges to scientific communities. Many physical, chemical and biological methods have been practiced to overcome this problem. The biological means of CO2 fixation using various microorganisms is gaining importance because database of ...

Clinical pathways for primary care: current use, interest and perceived usability.

Science.gov (United States)

Waters, Richard C; Toy, Jennifer M; Drechsler, Adam

2018-02-26

Translating clinical evidence to daily practice remains a challenge and may improve with clinical pathways. We assessed interest in and usability of clinical pathways by primary care professionals. An online survey was created. Interest in pathways for patient care and learning was assessed at start and finish. Participants completed baseline questions then pathway-associated question sets related to management of 2 chronic diseases. Perceived pathway usability was assessed using the system usability scale. Accuracy and confidence of answers was compared for baseline and pathway-assisted questions. Of 115 participants, 17.4% had used clinical pathways, the lowest of decision support tool types surveyed. Accuracy and confidence in answers significantly improved for all pathways. Interest in using pathways daily or weekly was above 75% for the respondents. There is low utilization of, but high interest in, clinical pathways by primary care clinicians. Pathways improve accuracy and confidence in answering written clinical questions.

Hybrid Composites Based on Carbon Fiber/Carbon Nanofilament Reinforcement

Directory of Open Access Journals (Sweden)

Mehran Tehrani

2014-05-01

Full Text Available Carbon nanofilament and nanotubes (CNTs have shown promise for enhancing the mechanical properties of fiber-reinforced composites (FRPs and imparting multi-functionalities to them. While direct mixing of carbon nanofilaments with the polymer matrix in FRPs has several drawbacks, a high volume of uniform nanofilaments can be directly grown on fiber surfaces prior to composite fabrication. This study demonstrates the ability to create carbon nanofilaments on the surface of carbon fibers employing a synthesis method, graphitic structures by design (GSD, in which carbon structures are grown from fuel mixtures using nickel particles as the catalyst. The synthesis technique is proven feasible to grow nanofilament structures—from ethylene mixtures at 550 °C—on commercial polyacrylonitrile (PAN-based carbon fibers. Raman spectroscopy and electron microscopy were employed to characterize the surface-grown carbon species. For comparison purposes, a catalytic chemical vapor deposition (CCVD technique was also utilized to grow multiwall CNTs (MWCNTs on carbon fiber yarns. The mechanical characterization showed that composites using the GSD-grown carbon nanofilaments outperform those using the CCVD-grown CNTs in terms of stiffness and tensile strength. The results suggest that further optimization of the GSD growth time, patterning and thermal shield coating of the carbon fibers is required to fully materialize the potential benefits of the GSD technique.

Transport properties for carbon chain sandwiched between heteroatom-doped carbon nanotubes with different doping sites

International Nuclear Information System (INIS)

Liu, Wenjiang; Deng, Xiaoqing; Cai, Shaohong

2016-01-01

The First-principles calculation is used to investigate the transport properties of a carbon chain connected with N-and/or B-doped caped carbon nanotube acting as electrodes. The I-V curves of the carbon chain are affected by the N/B doping sites, and rectifying behavior can be obtained distinctly when the carbon chain is just connected onto two doping atom sites (N- chain-B), and a weak rectification occurs when N (B) doping at other sites. Interestingly, the spin-filtering effects exist in the junction when it is doped at other sites, undoped system, or N-terminal carbon chains. However, no this behavior is found in N-chain-B and B-chain-B systems. The analysis on the transmission spectra, PDOS, LDOS, spin density, and the electron transmission pathways give an insight into the observed results for the system.

Transport properties for carbon chain sandwiched between heteroatom-doped carbon nanotubes with different doping sites

Energy Technology Data Exchange (ETDEWEB)

Liu, Wenjiang [Big Data and Information Engineering College of Guizhou University, Guiyang 550025 (China); Guizhou University of Finance and Economics, Guiyang 550025 (China); Deng, Xiaoqing, E-mail: xq-deng@163.com, E-mail: caish@mail.gufe.edu.cn [School of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China); Cai, Shaohong, E-mail: xq-deng@163.com, E-mail: caish@mail.gufe.edu.cn [Guizhou University of Finance and Economics, Guiyang 550025 (China)

2016-07-15

The First-principles calculation is used to investigate the transport properties of a carbon chain connected with N-and/or B-doped caped carbon nanotube acting as electrodes. The I-V curves of the carbon chain are affected by the N/B doping sites, and rectifying behavior can be obtained distinctly when the carbon chain is just connected onto two doping atom sites (N- chain-B), and a weak rectification occurs when N (B) doping at other sites. Interestingly, the spin-filtering effects exist in the junction when it is doped at other sites, undoped system, or N-terminal carbon chains. However, no this behavior is found in N-chain-B and B-chain-B systems. The analysis on the transmission spectra, PDOS, LDOS, spin density, and the electron transmission pathways give an insight into the observed results for the system.

Utilization of spent dregs for the production of activated carbon for CO2 adsorption

Directory of Open Access Journals (Sweden)

Serafin Jarosław

2017-06-01

Full Text Available The objective of this work was preparation of activated carbon from spent dregs for carbon dioxide adsorption. A saturated solution of KOH was used as an activating agent. Samples were carbonized in the furnace at the temperature of 550°C. Textural properties of activated carbons were obtained based on the adsorption-desorption isotherms of nitrogen at −196°C and carbon dioxide at 0°C. The specific surface areas of activated carbons were calculated by the Brunauer – Emmett – Teller equation. The volumes of micropores were obtained by density functional theory method. The highest CO2 adsorption was 9.54 mmol/cm3 at 0°C – and 8.50 mmol/cm3 at 25°C.

Quantitative trait loci and metabolic pathways

Science.gov (United States)

McMullen, M. D.; Byrne, P. F.; Snook, M. E.; Wiseman, B. R.; Lee, E. A.; Widstrom, N. W.; Coe, E. H.

1998-01-01

The interpretation of quantitative trait locus (QTL) studies is limited by the lack of information on metabolic pathways leading to most economic traits. Inferences about the roles of the underlying genes with a pathway or the nature of their interaction with other loci are generally not possible. An exception is resistance to the corn earworm Helicoverpa zea (Boddie) in maize (Zea mays L.) because of maysin, a C-glycosyl flavone synthesized in silks via a branch of the well characterized flavonoid pathway. Our results using flavone synthesis as a model QTL system indicate: (i) the importance of regulatory loci as QTLs, (ii) the importance of interconnecting biochemical pathways on product levels, (iii) evidence for “channeling” of intermediates, allowing independent synthesis of related compounds, (iv) the utility of QTL analysis in clarifying the role of specific genes in a biochemical pathway, and (v) identification of a previously unknown locus on chromosome 9S affecting flavone level. A greater understanding of the genetic basis of maysin synthesis and associated corn earworm resistance should lead to improved breeding strategies. More broadly, the insights gained in relating a defined genetic and biochemical pathway affecting a quantitative trait should enhance interpretation of the biological basis of variation for other quantitative traits. PMID:9482823

TRWG developmental pathway for biospecimen-based assessment modalities

Energy Technology Data Exchange (ETDEWEB)

Translational Research Working Group; Srivastava, Sudhir; Gray, Joe W.; Reid, Brian J.; Grad, Oren; Greenwood, Addison; Hawk, Ernest T.

2008-09-03

The Translational Research Working Group (TRWG) was created as a national initiative to evaluate the current status of NCI's investment in translational research and envision its future. The TRWG conceptualized translational research as a set of six developmental processes or pathways focused on various clinical goals. One of those pathways describes the development of biospecimen-based assays that utilize biomarkers for the detection, diagnosis, prognosis, and assessment of response to cancer treatment. The biospecimen-based assessment modality (BM) pathway was conceived not as comprehensive description of the corresponding real-world processes, but rather as a tool designed to facilitate movement of a candidate assay through the translational process to the point where it can be handed off for definitive clinical testing. This paper introduces the pathway in the context of prior work and discusses key challenges associated with the biomarker development process in light of the pathway.

An Examination of the Carbon Isotope Effects Associated with Amino Acid Biosynthesis

Science.gov (United States)

Scott, James H.; O'Brien, Diane M.; Emerson, David; Sun, Henry; McDonald, Gene D.; Salgado, Antonio; Fogel, Marilyn L.

2006-12-01

Stable carbon isotope ratios (δ13C) were determined for alanine, proline, phenylalanine, valine, leucine, isoleucine, aspartate (aspartic acid and asparagine), glutamate (glutamic acid and glutamine), lysine, serine, glycine, and threonine from metabolically diverse microorganisms. The microorganisms examined included fermenting bacteria, organotrophic, chemolithotrophic, phototrophic, methylotrophic, methanogenic, acetogenic, acetotrophic, and naturally occurring cryptoendolithic communities from the Dry Valleys of Antarctica. Here we demonstrated that reactions involved in amino acid biosynthesis can be used to distinguish amino acids formed by life from those formed by nonbiological processes. The unique patterns of δ13C imprinted by life on amino acids produced a biological bias. We also showed that, by applying discriminant function analysis to the δ13C value of a pool of amino acids formed by biological activity, it was possible to identify key aspects of intermediary carbon metabolism in the microbial world. In fact, microorganisms examined in this study could be placed within one of three metabolic groups: (1) heterotrophs that grow by oxidizing compounds containing three or more carbon-to-carbon bonds (fermenters and organotrophs), (2) autotrophs that grow by taking up carbon dioxide (chemolitotrophs and phototrophs), and (3) acetoclastic microbes that grow by assimilation of formaldehyde or acetate (methylotrophs, methanogens, acetogens, and acetotrophs). Furthermore, we demonstrated that cryptoendolithic communities from Antarctica grouped most closely with the autotrophs, which indicates that the dominant metabolic pathways in these communities are likely those utilized for CO2 fixation. We propose that this technique can be used to determine the dominant metabolic types in a community and reveal the overall flow of carbon in a complex ecosystem.