Influence of carbon source and inoculum type on anaerobic biomass adhesion on polyurethane foam in reactors fed with acid mine drainage.

PubMed

Rodriguez, Renata P; Zaiat, Marcelo

2011-04-01

This paper analyzes the influence of carbon source and inoculum origin on the dynamics of biomass adhesion to an inert support in anaerobic reactors fed with acid mine drainage. Formic acid, lactic acid and ethanol were used as carbon sources. Two different inocula were evaluated: one taken from an UASB reactor and other from the sediment of a uranium mine. The values of average colonization rates and the maximum biomass concentration (C(max)) were inversely proportional to the number of carbon atoms in each substrate. The highest C(max) value (0.35 g TVS g(-1) foam) was observed with formic acid and anaerobic sludge as inoculum. Maximum colonization rates (v(max)) were strongly influenced by the type of inoculum when ethanol and lactic acid were used. For both carbon sources, the use of mine sediment as inoculum resulted in a v(max) of 0.013 g TVS g(-1) foam day(-1), whereas 0.024 g TVS g(-1) foam day(-1) was achieved with anaerobic sludge. Copyright © 2011 Elsevier Ltd. All rights reserved.

Time-based comparative transcriptomics in engineered xylose-utilizing Saccharomyces cerevisiae identifies temperature-responsive genes during ethanol production.

PubMed

Ismail, Ku Syahidah Ku; Sakamoto, Takatoshi; Hasunuma, Tomohisa; Kondo, Akihiko

2013-09-01

Agricultural residues comprising lignocellulosic materials are excellent sources of pentose sugar, which can be converted to ethanol as fuel. Ethanol production via consolidated bioprocessing requires a suitable microorganism to withstand the harsh fermentation environment of high temperature, high ethanol concentration, and exposure to inhibitors. We genetically enhanced an industrial Saccharomyces cerevisiae strain, sun049, enabling it to uptake xylose as the sole carbon source at high fermentation temperature. This strain was able to produce 13.9 g/l ethanol from 50 g/l xylose at 38 °C. To better understand the xylose consumption ability during long-term, high-temperature conditions, we compared by transcriptomics two fermentation conditions: high temperature (38 °C) and control temperature (30 °C) during the first 12 h of fermentation. This is the first long-term, time-based transcriptomics approach, and it allowed us to discover the role of heat-responsive genes when xylose is the sole carbon source. The results suggest that genes related to amino acid, cell wall, and ribosomal protein synthesis are down-regulated under heat stress. To allow cell stability and continuous xylose uptake in order to produce ethanol, hexose transporter HXT5, heat shock proteins, ubiquitin proteins, and proteolysis were all induced at high temperature. We also speculate that the strong relationship between high temperature and increased xylitol accumulation represents the cell's mechanism to protect itself from heat degradation.

Effect of carbon sources on the growth and ethanol production of native yeast Pichia kudriavzevii ITV-S42 isolated from sweet sorghum juice.

PubMed

Díaz-Nava, L E; Montes-Garcia, N; Domínguez, J M; Aguilar-Uscanga, M G

2017-07-01

The importance of non-Saccharomyces yeast species in fermentation processes is widely acknowledged. Within this group, Pichia kudriavzevii ITV-S42 yeast strain shows particularly desirable characteristics for ethanol production. Despite this fact, a thorough study of the metabolic and kinetic characteristics of this strain is currently unavailable. The aim of this work is to study the nutritional requirements of Pichia kudriavzevii ITV-S42 strain and the effect of different carbon sources on the growth and ethanol production. Results showed that glucose and fructose were both assimilated and fermented, achieving biomass and ethanol yields of 0.37 and 0.32 gg -1 , respectively. Glycerol was assimilated but not fermented; achieving a biomass yield of 0.88 gg -1 . Xylose and sucrose were not metabolized by the yeast strain. Finally, the use of a culture medium enriched with salts and yeast extract favored glucose consumption both for growth and ethanol production, improving ethanol tolerance reported for this genre (35 g L -1 ) to 90 g L -1 maximum ethanol concentration (over 100%). Furthermore Pichia kudriavzevii ITV-S42 maintained its fermentative capacity up to 200 g L -1 initial glucose, demonstrating that this yeast is osmotolerant.

Land-use change and greenhouse gas emissions from corn and cellulosic ethanol

PubMed Central

2013-01-01

Background The greenhouse gas (GHG) emissions that may accompany land-use change (LUC) from increased biofuel feedstock production are a source of debate in the discussion of drawbacks and advantages of biofuels. Estimates of LUC GHG emissions focus mainly on corn ethanol and vary widely. Increasing the understanding of LUC GHG impacts associated with both corn and cellulosic ethanol will inform the on-going debate concerning their magnitudes and sources of variability. Results In our study, we estimate LUC GHG emissions for ethanol from four feedstocks: corn, corn stover, switchgrass, and miscanthus. We use new computable general equilibrium (CGE) results for worldwide LUC. U.S. domestic carbon emission factors are from state-level modelling with a surrogate CENTURY model and U.S. Forest Service data. This paper investigates the effect of several key domestic lands carbon content modelling parameters on LUC GHG emissions. International carbon emission factors are from the Woods Hole Research Center. LUC GHG emissions are calculated from these LUCs and carbon content data with Argonne National Laboratory’s Carbon Calculator for Land Use Change from Biofuels Production (CCLUB) model. Our results indicate that miscanthus and corn ethanol have the lowest (−10 g CO2e/MJ) and highest (7.6 g CO2e/MJ) LUC GHG emissions under base case modelling assumptions. The results for corn ethanol are lower than corresponding results from previous studies. Switchgrass ethanol base case results (2.8 g CO2e/MJ) were the most influenced by assumptions regarding converted forestlands and the fate of carbon in harvested wood products. They are greater than miscanthus LUC GHG emissions because switchgrass is a lower-yielding crop. Finally, LUC GHG emissions for corn stover are essentially negligible and insensitive to changes in model assumptions. Conclusions This research provides new insight into the influence of key carbon content modelling variables on LUC GHG emissions associated with the four bioethanol pathways we examined. Our results indicate that LUC GHG emissions may have a smaller contribution to the overall biofuel life cycle than previously thought. Additionally, they highlight the need for future advances in LUC GHG emissions estimation including improvements to CGE models and aboveground and belowground carbon content data. PMID:23575438

Characterization of an Arxula adeninivorans alcohol dehydrogenase involved in the metabolism of ethanol and 1-butanol.

PubMed

Kasprzak, Jakub; Rauter, Marion; Riechen, Jan; Worch, Sebastian; Baronian, Kim; Bode, Rüdiger; Schauer, Frieder; Kunze, Gotthard

2016-05-01

In this study, alcohol dehydrogenase 1 from Arxula adeninivorans (Aadh1p) was identified and characterized. Aadh1p showed activity with short and medium chain length primary alcohols in the forward reaction and their aldehydes in the reverse reaction. Aadh1p has 64% identity with Saccharomyces cerevisiae Adh1p, is localized in the cytoplasm and uses NAD(+) as cofactor. Gene expression analysis showed a low level increase in AADH1 gene expression with ethanol, pyruvate or xylose as the carbon source. Deletion of the AADH1 gene affects growth of the cells with 1-butanol, ethanol and glucose as the carbon source, and a strain which overexpressed the AADH1 gene metabolized 1-butanol more rapidly. An ADH activity assay indicated that Aadh1p is a major enzyme for the synthesis of ethanol and the degradation of 1-butanol in A. adeninivorans. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Source apportionment of carbonaceous aerosol in Sao Paulo using 13C and 14C measurements

NASA Astrophysics Data System (ADS)

Oyama, Beatriz; Andrade, Maria de Fatima; Holzinger, Rupert; Röckmann, Thomas; Meijer, Harro A. J.; Dusek, Ulrike

2016-04-01

The Metropolitan Area of Sao Paulo is affected by high aerosol concentrations, which contain a large fraction of organic material. Up to date, not much is known about the composition and origin of the organic aerosol in this city. We present the first source apportionment of the carbonaceous aerosol fraction in Sao Paulo, using stable (13C) and radioactive carbon isotopes (14C). 14C provides a clear-cut distinction between fossil sources, which contain no 14C, and contemporary sources such as biofuels, biomass burning, or biogenic sources, which contain a typical contemporary 14C/12C ratio. 13C can be used to distinguish C3 plants, such as maize and sugarcane, from C4 plants. This can help to identify a possible impact of sugarcane field burning in the rural areas of Sao Paulo State on the aerosol carbon in the city. In the first part of the study, we compare two tunnel studies: Tunnel 1 is frequented only by light duty vehicles, which run mainly on mixtures of gasoline with ethanol (gasohol, 25% ethanol and 85% gasoline) or hydrated ethanol (5% water and 95% ethanol). Tunnel 2 contains a significant fraction of heavy-duty diesel vehicles, and therefore the fraction of biofuels in the average fleet is lower. Comparison of 14C in organic and elemental carbon (OC and EC) shows that in both tunnels there is no significant contribution of biofuels to EC. Combusting ethanol-gasoline fuels in a vehicle engine does apparently not result in significant EC formation from ethanol. Biofuels contribute around 45% to OC in Tunnel 1 an only 20% in Tunnel 2, reflecting a strong impact of diesel vehicles in Tunnel 2. In the second part of the study we conduct a source apportionment of ambient aerosol carbon collected in a field study during winter (July-August) 2012. Ambient EC has two main sources, vehicular emissions and biomass burning. We estimate a contribution of vehicular sources to EC of roughly 90% during weekdays and 80% during weekends, using the 14C values measured in the tunnel studies. The absolute concentration of biomass burning EC is roughly 0.5 μg/m3 both during weekend and weekdays, whereas vehicular EC concentrations almost double during weekdays, increasing from 1.8 to 3.7 μg/m3 on average. OC concentrations are dominated by secondary carbon from vehicular emissions, both on weekdays and during weekends, however primary OC from biomass burning and contemporary secondary OC (from both biogenic and biomass burning emissions) are important fractions as well. Overall, primary biomass burning contributes between 10 and 30% to the carbonaceous aerosol in Sao Paulo. 13C measurements indicate that sugarcane burning could account for up to 15% of OC in the Sao Paulo metropolitan area.

BIODEGRADABILITY OF ALKYLATES AS A SOLE CARBON SOURCE IN THE PRESENCE OF ETHANOL OR BTEX

EPA Science Inventory

The biodegradability of alkylate compounds in serum bottles was investigated in the presence and absence of ethanol or benzene, toluene, ethylbenzene, and p-xylene (BTEX). The biomass was acclimated to three different alkylates, 2,3-dimethylpentane, 2,4-dimethylpentane, an...

L-arabinose fermenting yeast

DOEpatents

Zhang, Min; Singh, Arjun; Knoshaug, Eric; Franden, Mary Ann; Jarvis, Eric; Suominen, Pirkko

2010-12-07

An L-arabinose utilizing yeast strain is provided for the production of ethanol by introducing and expressing bacterial araA, araB and araD genes. L-arabinose transporters are also introduced into the yeast to enhance the uptake of arabinose. The yeast carries additional genomic mutations enabling it to consume L-arabinose, even as the only carbon source, and to produce ethanol. Methods of producing ethanol include utilizing these modified yeast strains. ##STR00001##

Carbon source-dependent effects of anaerobic soil disinfestation on soil microbiome and suppression of rhizoctonia solani AG-5 and pratylenchus penetrans

USDA-ARS?s Scientific Manuscript database

The effect of carbon source on efficacy of anaerobic soil disinfestation (ASD) toward suppression of apple root infection by Rhizoctonia solani AG-5 and Pratylenchus penetrans was examined. Orchard grass (GR), rice bran (RB), ethanol (ET), composted steer manure (CM) and Brassica juncea seed meal (S...

Carbon nanotube-like materials in the exhaust from a diesel engine using gas oil/ethanol mixing fuel with catalysts and sulfur.

PubMed

Suzuki, Shunsuke; Mori, Shinsuke

2017-08-01

Particulate matter from a diesel engine, including soot and carbon nanomaterials, was collected on a sampling holder and the structure of the materials was studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). As a result of employing gas oil/ethanol mixing fuel with sulfur and ferrocene/molybdenum as catalyst sources, formation of carbon nanotubes (CNT)-like materials in addition to soot was observed in the exhaust gas from a diesel engine. It was revealed that CNT-like materials were included among soot in our system only when the following three conditions were satisfied simultaneously: high ethanol fraction in fuel, high sulfur loading, and presence of catalyst sources in fuel. This study confirmed that if at least one of these three conditions was not satisfied, CNT-like materials were not observed in the exhaust from a diesel engine. These experimental results shown in this work provide insights into understanding CNT-like material formation mechanism in a diesel engine. Recent papers reported that carbon nanotube-like materials were included in the exhaust gas from engines, but conditions for carbon nanotube-like material formation have not been well studied. This work provides the required conditions for carbon nanotube-like material growth in a diesel engine, and this will be helpful for understanding the carbon nanotube-like material formation mechanism and taking countermeasures to preventing carbon nanotube-like material formation in a diesel engine.

Enhanced cyclic stability of SnS microplates with conformal carbon coating derived from ethanol vapor deposition for sodium-ion batteries

NASA Astrophysics Data System (ADS)

Li, Xiang; Liu, Jiangwen; Ouyang, Liuzhang; Yuan, Bin; Yang, Lichun; Zhu, Min

2018-04-01

Carbon coated SnS microplates (SnS@C MPs) were prepared via a facile chemical vapor deposition method using SnS2 nanoflakes as precursor and ethanol vapor as carbon source. The carbon coating restrains the growth of SnS during the heat treatment. Furthermore, it improves the electronic conductivity as well as accommodates volume variations of SnS during the sodiation and desodiation processes. Therefore, the rate capability and cycle performance of the SnS@C MPs as anode materials for sodium-ion batteries are remarkably enhanced compared with the bare SnS and the SnS2 precursor. At current densities of 0.1, 0.2, 0.5, 1 and 2 A g-1, the optimized SnS@C MPs exhibit stable capacities of 602.9, 532.1, 512.2, 465.9 and 427.2 mAh g-1, respectively. At 1 A g-1, they show a reversible capacity of 528.8 mAh g-1 in the first cycle, and maintain 444.7 mAh g-1 after 50 cycles, with capacity retention of 84.1%. The carbon coating through chemical vapor deposition using ethanol vapor as carbon sources is green, simple and cost-effective, which shows great promise to improve the reversible Na+ storage of electrode materials.

Use of natural gas, methanol, and ethanol fuel emulsions as environmentally friendly energy carriers for mobile heat power plants

NASA Astrophysics Data System (ADS)

Likhanov, V. A.; Lopatin, O. P.

2017-12-01

The need for using environmentally friendly energy carriers for mobile heat power plants (HPPs) is grounded. Ecologically friendly sources of energy, such as natural gas as well as renewable methyl and ethyl alcohols, are investigated. In order to develop, determine, and optimize the composition of environmentally friendly energy carriers for an HPP, the latter has been tested when working on diesel fuel (DF), compressed natural gas (CNG), and methanol and ethanol fuel emulsions (MFE, EFE). It has been experimentally established that, for the application of environmentally friendly energy carriers for a 4Ch 11.0/12.5 diesel engine of a mobile fuel and power plant, it is necessary to maintain the following ratio of components when working on CNG: 80% gas and 20% DF primer portion. When working on an alcohol mixture, emulsions of the following composition were used: 25% alcohol (methanol or ethanol), 0.5% detergent-dispersant additive succinimide C-5A, 7% water, and 67.5% DF. When this diesel passed from oil DF to environmentally friendly energy sources, it allowed for the reduction of the content of exhaust gases (EG) (1) when working on CNG with recirculation of exhaust gases (EGR) (recirculation was used to eliminate the increased amount of nitric oxides by using CNG): carbon black by 5.8 times, carbon dioxide by 45.9%, and carbon monoxide by 23.8%; (2) when working on MFE: carbon black by 6.4 times, nitrogen oxides by 29.6%, carbon dioxide by 10.1%, and carbon oxide by 47.6%; (3) when working on EFE: carbon black by 4.8 times; nitrogen oxides by 40.3%, carbon dioxide by 26.6%, and carbon monoxide by 28.6%. The prospects of use of environmentally friendly energy carriers in diesels of mobile HPPs, such as natural gas, ethanol, and methanol, has been determined.

Graphene Synthesis by Plasma-Enhanced CVD Growth with Ethanol

DOE PAGES

Campo, Teresa; Cotto, María; Márquez, Francisco; ...

2016-03-01

A modified route to synthesize graphene flakes is proposed using the Chemical Vapor Deposition (CVD) technique, by using copper substrates as supports. The carbon source used was ethanol, the synthesis temperature was 950°C and the pressure was controlled along the whole process. In this CVD synthesis process the incorporation of the carbon source was produced at low pressure and 950°C inducing the appearance of a plasma blue flash inside the quartz tube. Apparently, the presence of this plasma blue flash is required for obtaining graphene flakes. The synthesized graphene was characterized by different techniques, showing the presence of non-oxidized graphenemore » with high purity.« less

Impact of external carbon dose on the removal of micropollutants using methanol and ethanol in post-denitrifying Moving Bed Biofilm Reactors.

PubMed

Torresi, Elena; Escolà Casas, Mònica; Polesel, Fabio; Plósz, Benedek G; Christensson, Magnus; Bester, Kai

2017-01-01

Addition of external carbon sources to post-denitrification systems is frequently used in wastewater treatment plants to enhance nitrate removal. However, little is known about the fate of micropollutants in post-denitrification systems and the influence of external carbon dosing on their removal. In this study, we assessed the effects of two different types and availability of commonly used carbon sources -methanol and ethanol- on the removal of micropollutants in biofilm systems. Two laboratory-scale moving bed biofilm reactors (MBBRs), containing AnoxKaldnes K1 carriers with acclimated biofilm from full-scale systems, were operated in continuous-flow using wastewater dosed with methanol and ethanol, respectively. Batch experiments with 22 spiked pharmaceuticals were performed to assess removal kinetics. Acetyl-sulfadiazine, atenolol, citalopram, propranolol and trimethoprim were easily biotransformed in both MBBRs (biotransformations rate constants k bio between 1.2 and 12.9 L g biomass -1  d -1 ), 13 compounds were moderately biotransformed (rate constants between 0.2 and 2 L g biomass -1  d -1 ) and 4 compounds were recalcitrant. The methanol-dosed MBBR showed higher k bio (e.g., 1.5-2.5-fold) than in the ethanol-dosed MBBR for 9 out of the 22 studied compounds, equal k bio for 10 compounds, while 3 compounds (i.e., targeted sulfonamides) were biotransformed faster in the ethanol-dosed MBBR. While biotransformation of most of the targeted compounds followed first-order kinetics, removal of venlafaxine, carbamazepine, sulfamethoxazole and sulfamethizole could be described with a cometabolic model. Analyses of the microbial composition in the biofilms using 16S rRNA amplicon sequencing revealed that the methanol-dosed MBBR contained higher microbial richness than the one dosed with ethanol, suggesting that improved biotransformation of targeted compounds could be associated with higher microbial richness. During continuous-flow operation, at conditions representative of full-scale denitrification systems (hydraulic residence time = 2 h), the removal efficiencies of micropollutants were below 35% in both MBBRs, with the exception of atenolol and trimethoprim (>80%). Overall, this study demonstrated that MBBRs used for post-denitrification could be optimized to enhance the biotransformation of a number of micropollutants by accounting for optimal carbon sources and extended residence time. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bioethanol production by heterologous expression of Pdc and AdhII in Streptomyces lividans.

PubMed

Lee, Jae Sun; Chi, Won-Jae; Hong, Soon-Kwang; Yang, Ji-Won; Chang, Yong Keun

2013-07-01

Two genes from Zymomonas mobilis that are responsible for ethanol production, pyruvate decarboxylase (pdc) and alcohol dehydrogenase II (adhII), were heterologously expressed in the Gram-positive bacterium Streptomyces lividans TK24. An examination of carbon distribution revealed that a significant portion of carbon metabolism was switched from biomass and organic acid biosynthesis to ethanol production upon the expression of pdc and adhII. The recombinant S. lividans TK24 produced ethanol from glucose with a yield of 23.7% based on the carbohydrate consumed. The recombinant was able to produce ethanol from xylose, L-arabinose, mannose, L-rhamnose, galactose, ribose, and cellobiose with yields of 16.0, 25.6, 21.5, 33.6, 30.6, 14.6, and 33.3%, respectively. Polymeric substances such as starch and xylan were directly converted to ethanol by the recombinant with ethanol yields of 18.9 and 8.8%, respectively. The recombinant S. lividans TK24/Tpet developed in this study is potentially a useful microbial resource for ethanol production from various sources of biomasses, especially microalgae.

High value added lipids produced by microorganisms: a potential use of sugarcane vinasse.

PubMed

Fernandes, Bruna Soares; Vieira, João Paulo Fernandes; Contesini, Fabiano Jares; Mantelatto, Paulo Eduardo; Zaiat, Marcelo; Pradella, José Geraldo da Cruz

2017-12-01

This review aims to present an innovative concept of high value added lipids produced by heterotrophic microorganisms, bacteria and fungi, using carbon sources, such as sugars, acids and alcohols that could come from sugarcane vinasse, which is the main byproduct from ethanol production that is released in the distillation step. Vinasse is a rich carbon source and low-cost feedstock produced in large amounts from ethanol production. In 2019, the Brazilian Ministry of Agriculture, Livestock and Food Supply estimates that growth of ethanol domestic consumption will be 58.8 billion liters, more than double the amount in 2008. This represents the annual production of more than 588 billion liters of vinasse, which is currently used as a fertilizer in the sugarcane crop, due to its high concentration of minerals, mainly potassium. However, studies indicate some disadvantages such as the generation of Greenhouse Gas emission during vinasse distribution in the crop, as well as the possibility of contaminating the groundwater and soil. Therefore, the development of programs for sustainable use of vinasse is a priority. One profitable alternative is the fermentation of vinasse, followed by an anaerobic digester, in order to obtain biomaterials such as lipids, other byproducts, and methane. Promising high value added lipids, for instance carotenoids and polyunsaturated fatty acids (PUFAS), with a predicted market of millions of US$, could be produced using vinasse as carbon source, to guide an innovative concept for sustainable production. Example of lipids obtained from the fermentation of compounds present in vinasse are vitamin D, which comes from yeast sucrose fermentation and Omega 3, which can be obtained by bacteria and fungi fermentation. Additionally, several other compounds present in vinasse can be used for this purpose, including sucrose, ethanol, lactate, pyruvate, acetate and other carbon sources. Finally, this paper illustrates the potential market and microbial processes, using microorganisms, for lipid production.

High-Selectivity Electrochemical Conversion of CO 2 to Ethanol using a Copper Nanoparticle/N-Doped Graphene Electrode

DOE PAGES

Song, Yang; Peng, Rui; Hensley, Dale K.; ...

2016-09-28

Carbon dioxide is a pollutant, but also a potential carbon source provided an efficient means to convert it to useful products. Herein we report a nanostructured catalyst for the direct electrochemical reduction of dissolved CO 2 to ethanol with high Faradaic efficiency (63%) and high selectivity (84%). The catalyst is comprised of Cu nanoparticle on a highly textured, N-doped graphene film. Detailed electrochemical analysis and complementary DFT calculations indicate a novel mechanism in which multiple active sites, working sequentially, control the coupling of carbon monoxide radicals and mediate the subsequent electrochemical reduction to alcohol.

Overexpression of the genes PDC1 and ADH1 activates glycerol conversion to ethanol in the thermotolerant yeast Ogataea (Hansenula) polymorpha.

PubMed

Kata, Iwona; Semkiv, Marta V; Ruchala, Justyna; Dmytruk, Kostyantyn V; Sibirny, Andriy A

2016-08-01

Conversion of byproduct from biodiesel production glycerol to high-value compounds is of great importance. Ethanol is considered a promising product of glycerol bioconversion. The methylotrophic thermotolerant yeast Ogataea (Hansenula) polymorpha is of great interest for this purpose as the glycerol byproduct contains methanol and heavy metals as contaminants, and this yeast utilizes methanol and is relatively resistant to heavy metals. Besides, O. polymorpha shows robust growth on glycerol and produces ethanol from various carbon sources. The thermotolerance of this yeast is an additional advantage, allowing increased fermentation temperature to 45-48 °C, leading to increased rate of the fermentation process and a fall in the cost of distillation. The wild-type strain of O. polymorpha produces insignificant amounts of ethanol from glycerol (0.8 g/l). Overexpression of PDC1 coding for pyruvate decarboxylase enhanced ethanol production up to 3.1 g/l, whereas simultaneous overexpression of PDC1 and ADH1 (coding for alcohol dehydrogenase) led to further increase in ethanol production from glycerol. Moreover, the increased temperature of fermentation up to 45 °C stimulated the production of ethanol from glycerol used as the only carbon source up to 5.0 g/l, which exceeds the data obtained by methylotrophic yeast strains reported so far. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Galactose utilization sheds new light on sugar metabolism in the sequenced strain Dekkera bruxellensis CBS 2499.

PubMed

Moktaduzzaman, Md; Galafassi, Silvia; Capusoni, Claudia; Vigentini, Ileana; Ling, Zhihao; Piškur, Jure; Compagno, Concetta

2015-03-01

Dekkera bruxellensis and Saccharomyces cerevisiae are considered two phylogenetically distant relatives, but they share several industrial relevant traits such as the ability to produce ethanol under aerobic conditions (Crabtree effect), high tolerance towards ethanol and acids, and ability to grow without oxygen. Beside a huge adaptability, D. bruxellensis exhibits a broader spectrum in utilization of carbon and nitrogen sources in comparison to S. cerevisiae. With the aim to better characterize its carbon source metabolism and regulation, the usage of galactose and the role that glucose plays on sugar metabolism were investigated in D. bruxellensis CBS 2499. The results indicate that in this yeast galactose is a non-fermentable carbon source, in contrast to S. cerevisiae that can ferment it. In particular, its metabolism is affected by the nitrogen source. Interestingly, D. bruxellensis CBS 2499 exhibits the 'short-term Crabtree effect', and the expression of genes involved in galactose utilization and in respiratory metabolism is repressed by glucose, similarly to what occurs in S. cerevisiae. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.

Automated UV-C mutagenesis of Kluyveromyces marxianus NRRL Y-1109 and selection for microaerophilic growth and ethanol production at elevated temperature on biomass sugars.

PubMed

Hughes, Stephen R; Bang, Sookie S; Cox, Elby J; Schoepke, Andrew; Ochwat, Kate; Pinkelman, Rebecca; Nelson, Danielle; Qureshi, Nasib; Gibbons, William R; Kurtzman, Cletus P; Bischoff, Kenneth M; Liu, Siqing; Cote, Gregory L; Rich, Joseph O; Jones, Marjorie A; Cedeño, David; Doran-Peterson, Joy; Riaño-Herrera, Nestor M; Rodríguez-Valencia, Nelson; López-Núñez, Juan C

2013-08-01

The yeast Kluyveromyces marxianus is a potential microbial catalyst for fuel ethanol production from a wide range of biomass substrates. To improve its growth and ethanol yield at elevated temperature under microaerophilic conditions, K. marxianus NRRL Y-1109 was irradiated with UV-C using automated protocols on a robotic platform for picking and spreading irradiated cultures and for processing the resulting plates. The plates were incubated under anaerobic conditions on xylose or glucose for 5 mo at 46 °C. Two K. marxianus mutant strains (designated 7-1 and 8-1) survived and were isolated from the glucose plates. Both mutant strains, but not wild type, grew aerobically on glucose at 47 °C. All strains grew anaerobically at 46 °C on glucose, galactose, galacturonic acid, and pectin; however, only 7-1 grew anaerobically on xylose at 46 °C. Saccharomyces cerevisiae NRRL Y-2403 did not grow at 46 °C on any of these substrates. With glucose as a carbon source, ethanol yield after 3 d at 46 °C was higher for 8-1 than for wild type (0.51 and 0.43 g ethanol/g glucose, respectively). With galacturonic acid as a carbon source, the ethanol yield after 7 d at 46 °C was higher for 7-1 than for wild type (0.48 and 0.34 g ethanol/g galacturonic acid, respectively). These mutant strains have potential application in fuel ethanol production at elevated temperature from sugar constituents of starch, sucrose, pectin, and cellulosic biomass.

Bifunctional catalyst of graphite-encapsulated iron compound nanoparticle for magnetic carbon nanotubes growth by chemical vapor deposition

NASA Astrophysics Data System (ADS)

Saraswati, Teguh Endah; Prasiwi, Oktaviana Dewi Indah; Masykur, Abu; Anwar, Miftahul

2017-01-01

The carbon nanotube has widely taken great attractive in carbon nanomaterial research and application. One of its preparation methods is catalytic chemical vapor deposition (CCVD) using catalyst i.e. iron, nickel, etc. Generally, except the catalyst, carbon source gasses as the precursor are still required. Here, we report the use of the bifunctional material of Fe3O4/C which has an incorporated core/shell structures of carbon-encapsulated iron compound nanoparticles. The bifunctional catalyst was prepared by submerged arc discharge that simply performed using carbon and carbon/iron oxide electrodes in ethanol 50%. The prepared material was then used as a catalyst in thermal chemical vapor deposition at 800°C flown with ethanol vapor as the primer carbon source in a low-pressure condition. This catalyst might play a dual role as a catalyst and secondary carbon source for growing carbon nanotubes at the time. The synthesized products were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. The successful formation of carbon nanotubes was assigned by the shifted X-ray diffracted peak of carbon C(002), the iron oxides of Fe3O4 and γ-Fe2O3, and the other peaks which were highly considered to the other carbon allotropes with sp2 hybridization structures. The other assignment was studied by electron microscopy which successfully observed the presence of single-wall carbon nanotubes. In addition, the as-prepared carbon nanotubes have a magnetic property which was induced by the remaining of metal catalyst inside the CNT.

Corrigendum to "Sinusoidal potential cycling operation of a direct ethanol fuel cell to improving carbon dioxide yields" [J. Power Sources 268 (5 December 2014) 439-442

NASA Astrophysics Data System (ADS)

Majidi, Pasha; Pickup, Peter G.

2016-09-01

The authors regret that Equation (5) is incorrect and has resulted in errors in Fig. 4 and the efficiencies stated on p. 442. The corrected equation, figure and text are presented below. In addition, the title should be 'Sinusoidal potential cycling operation of a direct ethanol fuel cell to improve carbon dioxide yields', and the reversible cell potential quoted on p. 441 should be 1.14 V. The authors would like to apologise for any inconvenience caused.

Enhanced biological phosphorus removal with different carbon sources.

PubMed

Shen, Nan; Zhou, Yan

2016-06-01

Enhanced biological phosphorus removal (EBPR) process is one of the most economical and sustainable methods for phosphorus removal from wastewater. However, the performance of EBPR can be affected by available carbon sources types in the wastewater that may induce different functional microbial communities in the process. Glycogen accumulating organisms (GAOs) and polyphosphate accumulating organisms (PAOs) are commonly found by coexisting in the EBPR process. Predominance of GAO population may lead to EBPR failure due to the competition on carbon source with PAO without contributing phosphorus removal. Carbon sources indeed play an important role in alteration of PAOs and GAOs in EBPR processes. Various types of carbon sources have been investigated for EBPR performance. Certain carbon sources tend to enrich specific groups of GAOs and/or PAOs. This review summarizes the types of carbon sources applied in EBPR systems and highlights the roles of these carbon sources in PAO and GAO competition. Both single (e.g., acetate, propionate, glucose, ethanol, and amino acid) and complex carbon sources (e.g., yeast extract, peptone, and mixed carbon sources) are discussed in this review. Meanwhile, the environmental friendly and economical carbon sources that are derived from waste materials, such as crude glycerol and wasted sludge, are also discussed and compared.

Landuse Carbon Implications of a Drawdown of Ethanol Production and an Increase in Well-Managed Pastures

NASA Astrophysics Data System (ADS)

Hellwinckel, C. M.; Phillips, J.

2011-12-01

Over the past 10 years, commodity grain prices have doubled, and world commodity prices have reached their highest levels in over 30 years. The rise in prices culminated in the food price spikes of 2008 and 2011, where food riots erupted in 40 countries. Although studies have pointed to a number of factors leading to the increased food prices, the ethanol industry, whether deservingly or not, is seen as the major factor behind the price spikes. Several recent studies have contributed to the poor public opinion of ethanol by concluding that ethanol is neither a net energy source nor a net reducer of carbon emissions. The impact of these research reports combined with recent spikes in commodity prices has led to fierce political efforts to reduce or eliminate subsidies for ethanol. Opponents of ethanol subsidization won a significant battle with Congress recently voting to eliminate federal blender's tax credits and ethanol import tariffs. If another sharp spike in commodity prices occurs in the near future, some have speculated that ethanol production mandates could be scaled back or eliminated. In the span of less than three years the expected role of ethanol in the agricultural sector has gone from one of rapid growth and longevity, to one of which the societal benefits are being strongly questioned. In light of the rapidly changing expectations regarding the future of ethanol, we believe it is an appropriate time to evaluate the landuse and carbon implications of a scaling down of ethanol production and investigating permanent managed pasture as an alternative land use that could provide carbon benefits. Various USDA programs to promote conservation of, or conversion to, permanent pasture or grassland exist primarily based on the value of decreasing the potential for soil erosion as well as improving water quality. Although grazing systems have long been associated with land degradation in the arid and semi-arid west, new management approaches utilizing some form of rotational grazing are believed to reverse degradation and potentially lead to soil and pasture improvement if well managed, with implications for soil carbon storage. As the debate over societal subsidization of ethanol continues, the scientific communities should prepare for a potential drawdown of ethanol, and be aware of the potential land use impacts. An integrated biogeophysical socioeconomic model is used to evaluate three levels of potential reductions in ethanol production along with the possibility of conversion of non-profitable cropland to pasture management. The integrated model (POLYSYS) is driven by data on economics, terrestrial carbon dynamics, remotely-sensed land cover, and energy consumption. Preliminary results indicate that up to 10 million hectares of cropland could convert to pastureland, reducing agricultural land use emissions by nearly 10 teragrams carbon equivalent (TgCeq), a 36% decline in agricultural land use carbon equivalent emissions.

Three alcohol dehydrogenase genes and one acetyl-CoA synthetase gene are responsible for ethanol utilization in Yarrowia lipolytica.

PubMed

Gatter, Michael; Ottlik, Stephanie; Kövesi, Zsolt; Bauer, Benjamin; Matthäus, Falk; Barth, Gerold

2016-10-01

The non-conventional yeast Yarrowia lipolytica is able to utilize a wide range of different substrates like glucose, glycerol, ethanol, acetate, proteins and various hydrophobic molecules. Although most metabolic pathways for the utilization of these substrates have been clarified by now, it was not clear whether ethanol is oxidized by alcohol dehydrogenases or by an alternative oxidation system inside the cell. In order to detect the genes that are required for ethanol utilization in Y. lipolytica, eight alcohol dehydrogenase (ADH) genes and one alcohol oxidase gene (FAO1) have been identified and respective deletion strains were tested for their ability to metabolize ethanol. As a result of this, we found that the availability of ADH1, ADH2 or ADH3 is required for ethanol utilization in Y. lipolytica. A strain with deletions in all three genes is lacking the ability to utilize ethanol as sole carbon source. Although Adh2p showed by far the highest enzyme activity in an in vitro assay, the availability of any of the three genes was sufficient to enable a decent growth. In addition to ADH1, ADH2 and ADH3, an acetyl-CoA synthetase encoding gene (ACS1) was found to be essential for ethanol utilization. As Y. lipolytica is a non-fermenting yeast, it is neither able to grow under anaerobic conditions nor to produce ethanol. To investigate whether Y. lipolytica may produce ethanol, the key genes of alcoholic fermentation in S. cerevisiae, ScADH1 and ScPDC1, were overexpressed in an ADH and an ACS1 deletion strain. However, instead of producing ethanol, the respective strains regained the ability to use ethanol as single carbon source and were still not able to grow under anaerobic conditions. Copyright © 2016 Elsevier Inc. All rights reserved.

L-arabinose fermenting yeast

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Min; Singh, Arjun; Suominen, Pirkko

An L-arabinose utilizing yeast strain is provided for the production of ethanol by introducing and expressing bacterial araA, araB and araD genes. L-arabinose transporters are also introduced into the yeast to enhance the uptake of arabinose. The yeast carries additional genomic mutations enabling it to consume L-arabinose, even as the only carbon source, and to produce ethanol. A yeast strain engineered to metabolize arabinose through a novel pathway is also disclosed. Methods of producing ethanol include utilizing these modified yeast strains.

L-arabinose fermenting yeast

DOEpatents

Zhang, Min; Singh, Arjun; Suominen, Pirkko; Knoshaug, Eric; Franden, Mary Ann; Jarvis, Eric

2014-09-23

An L-arabinose utilizing yeast strain is provided for the production of ethanol by introducing and expressing bacterial araA, araB and araD genes. L-arabinose transporters are also introduced into the yeast to enhance the uptake of arabinose. The yeast carries additional genomic mutations enabling it to consume L-arabinose, even as the only carbon source, and to produce ethanol. A yeast strain engineered to metabolize arabinose through a novel pathway is also disclosed. Methods of producing ethanol include utilizing these modified yeast strains.

Electrocatalytic activity of ZnS nanoparticles in direct ethanol fuel cells

NASA Astrophysics Data System (ADS)

Bredol, Michael; Kaczmarek, Michał; Wiemhöfer, Hans-Dieter

2014-06-01

Low temperature fuel cells consuming ethanol without reformation would be a major step toward the use of renewable energy sources from biomass. However, the necessary electrodes and electrocatalysts still are far from being perfect and suffer from various poisoning and deactivation processes. This work describes investigations on systems using carbon/ZnS-based electrocatalysts for ethanol oxidation in complete membrane electrode assemblies (MEAs). MEAs were built on Nafion membranes with active masses prepared from ZnS nanoparticles and Vulcan carbon support. Under operation, acetic acid and acetaldehyde were identified and quantified as soluble oxidation products, whereas the amount of CO2 generated could not be quantified directly. Overall conversion efficiencies of up to 25% were estimated from cells operated over prolonged time. From polarization curves, interrupt experiments and analysis of reaction products, mass transport problems (concentration polarization) and breakthrough losses were found to be the main deficiencies of the ethanol oxidation electrodes fabricated so far.

Nitrate addition to groundwater impacted by ethanol-blended fuel accelerates ethanol removal and mitigates the associated metabolic flux dilution and inhibition of BTEX biodegradation

NASA Astrophysics Data System (ADS)

Corseuil, Henry Xavier; Gomez, Diego E.; Schambeck, Cássio Moraes; Ramos, Débora Toledo; Alvarez, Pedro J. J.

2015-03-01

A comparison of two controlled ethanol-blended fuel releases under monitored natural attenuation (MNA) versus nitrate biostimulation (NB) illustrates the potential benefits of augmenting the electron acceptor pool with nitrate to accelerate ethanol removal and thus mitigate its inhibitory effects on BTEX biodegradation. Groundwater concentrations of ethanol and BTEX were measured 2 m downgradient of the source zones. In both field experiments, initial source-zone BTEX concentrations represented less than 5% of the dissolved total organic carbon (TOC) associated with the release, and measurable BTEX degradation occurred only after the ethanol fraction in the multicomponent substrate mixture decreased sharply. However, ethanol removal was faster in the nitrate amended plot (1.4 years) than under natural attenuation conditions (3.0 years), which led to faster BTEX degradation. This reflects, in part, that an abundant substrate (ethanol) can dilute the metabolic flux of target pollutants (BTEX) whose biodegradation rate eventually increases with its relative abundance after ethanol is preferentially consumed. The fate and transport of ethanol and benzene were accurately simulated in both releases using RT3D with our general substrate interaction module (GSIM) that considers metabolic flux dilution. Since source zone benzene concentrations are relatively low compared to those of ethanol (or its degradation byproduct, acetate), our simulations imply that the initial focus of cleanup efforts (after free-product recovery) should be to stimulate the degradation of ethanol (e.g., by nitrate addition) to decrease its fraction in the mixture and speed up BTEX biodegradation.

Nitrate addition to groundwater impacted by ethanol-blended fuel accelerates ethanol removal and mitigates the associated metabolic flux dilution and inhibition of BTEX biodegradation.

PubMed

Corseuil, Henry Xavier; Gomez, Diego E; Schambeck, Cássio Moraes; Ramos, Débora Toledo; Alvarez, Pedro J J

2015-03-01

A comparison of two controlled ethanol-blended fuel releases under monitored natural attenuation (MNA) versus nitrate biostimulation (NB) illustrates the potential benefits of augmenting the electron acceptor pool with nitrate to accelerate ethanol removal and thus mitigate its inhibitory effects on BTEX biodegradation. Groundwater concentrations of ethanol and BTEX were measured 2 m downgradient of the source zones. In both field experiments, initial source-zone BTEX concentrations represented less than 5% of the dissolved total organic carbon (TOC) associated with the release, and measurable BTEX degradation occurred only after the ethanol fraction in the multicomponent substrate mixture decreased sharply. However, ethanol removal was faster in the nitrate amended plot (1.4 years) than under natural attenuation conditions (3.0 years), which led to faster BTEX degradation. This reflects, in part, that an abundant substrate (ethanol) can dilute the metabolic flux of target pollutants (BTEX) whose biodegradation rate eventually increases with its relative abundance after ethanol is preferentially consumed. The fate and transport of ethanol and benzene were accurately simulated in both releases using RT3D with our general substrate interaction module (GSIM) that considers metabolic flux dilution. Since source zone benzene concentrations are relatively low compared to those of ethanol (or its degradation byproduct, acetate), our simulations imply that the initial focus of cleanup efforts (after free-product recovery) should be to stimulate the degradation of ethanol (e.g., by nitrate addition) to decrease its fraction in the mixture and speed up BTEX biodegradation. Copyright © 2014 Elsevier B.V. All rights reserved.

Influence of carbon sources on the viability and resuscitation of Acetobacter senegalensis during high-temperature gluconic acid fermentation.

PubMed

Shafiei, Rasoul; Zarmehrkhorshid, Raziyeh; Mounir, Majid; Thonart, Philippe; Delvigne, Frank

2017-05-01

Much research has been conducted about different types of fermentation at high temperature, but only a few of them have studied cell viability changes during high-temperature fermentation. In this study, Acetobacter senegalensis, a thermo-tolerant strain, was used for gluconic acid production at 38 °C. The influences of different carbon sources and physicochemical conditions on cell viability and the resuscitation of viable but nonculturable (VBNC) cells formed during fermentation were studied. Based on the obtained results, A. senegalensis could oxidize 95 g l - 1 glucose to gluconate at 38 °C (pH 5.5, yield 83%). However, despite the availability of carbon and nitrogen sources, the specific rates of glucose consumption (q s ) and gluconate production (q p ) reduced progressively. Interestingly, gradual q s and q p reduction coincided with gradual decrease in cellular dehydrogenase activity, cell envelope integrity, and cell culturability as well as with the formation of VBNC cells. Entry of cells into VBNC state during stationary phase partly stemmed from high fermentation temperature and long-term oxidation of glucose, because just about 48% of VBNC cells formed during stationary phase were resuscitated by supplementing the culture medium with an alternative favorite carbon source (low concentration of ethanol) and/or reducing incubation temperature to 30 °C. This indicates that ethanol, as a favorable carbon source, supports the repair of stressed cells. Since formation of VBNC cells is often inevitable during high-temperature fermentation, using an alternative carbon source together with changing physicochemical conditions may enable the resuscitation of VBNC cells and their use for several production cycles.

Novel Biocatalytic Platform for Ethanol Production from Lignocellulosic Feedstock

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Chyi-Shin; Tachea, Firehiwot; Brown, Sarah

2017-01-23

The goals of the CRADA were achieved by illustrating the scalability of immobilized yeast technology, demonstrating lignocellulosic feedstock consumption by the immobilized cells, and confirming Microvi’s proprietary polymer matrix ethanol toxicity tolerance. We conducted fermentations at 2L and 300L scales. For carbon source, we performed pretreatment and saccharification at 100L scale to produce lignocellulosic sugars with glucose and xylose.

Ethanol used as an environmentally sustainable energy resource for thermal power plants

NASA Astrophysics Data System (ADS)

Markov, V. A.; Biryukov, V. V.; Kas'kov, S. I.

2016-09-01

Justification of using renewable energy sources and a brief analysis of their application prospects is given. The most common renewable energy sources for mobile thermal power plants are presented. The possibilities and ways of using ethanol as an energy source for such plants with diesel engines are analyzed. It is shown that it is feasible to add small amounts of ethanol to oil diesel fuel (DF) for obtaining an environmentally sustainable energy source for diesel engines. Therewith, a stable mixture of components can be obtained by adding anhydrous (absolute) ethanol to the oil fuel. The authors studied a mixture containing 4% (by volume) of absolute ethanol and 96% of oil DF. The physicochemical properties of the mixture and each of its components are presented. Diesel engine of the type D-245.12S has been experimentally studied using the mixture of DF and ethanol. The possibility of reducing the toxicity level of the exhaust emissions when using this mixture as an energy source for diesel engines of mobile power plants is shown. Transition of the studied diesel engine from oil DF to its mixture with ethanol made it possible to reduce the smoke capacity of the exhaust gases by 15-25% and to decrease the specific mass emissions of nitrogen oxides by 17.4%. In this case, we observed a slight increase in the exhaust gas emissions of carbon monoxide and light unburned hydrocarbons, which, however, can easily be eliminated by providing the exhaust system of a diesel engine with a catalytic converter. It is noted that the studied mixture composition should be optimized. The conclusion is made that absolute ethanol is a promising ecofriendly additive to oil diesel fuel and should be used in domestic diesel engines.

Microbial metabolism of tholin

NASA Astrophysics Data System (ADS)

Stoker, C. R.; Boston, P. J.; Mancinelli, R. L.; Segal, W.; Khare, B. N.; Sagan, C.

1990-05-01

In this paper, we show that a wide variety of common soil bacteria are able to obtain their carbon and energy needs from tholin (a class of complex organic heteropolymers thought to be widely distributed through the solar system; in this case tholin was produced by passage of electrical discharge through a mixture of methane, ammonia, and water vapor). We have isolated aerobic, anaerobic, and facultatively anaerobic bacteria which are able to use tholin as a sole carbon source. Organisms which metabolize tholin represent a variety of bacterial genera including Clostridium, Pseudomonas, Bacillus, Acinetobacter, Paracoccus, Alcaligenes, Micrococcus, Cornebacterium, Aerobacter, Arthrobacter, Flavobacterium,and Actinomyces. Aerobic tholin-using bacteria were firrst isolated from soils containing unusual or sparse carbon sources. Some of these organisms were found to be facultatively anaerobic. Strictly anaerobic tholin-using bacteria were isolated from both carbon-rich and carbon-poor anaerobic lake muds. In addition, both aerobic and anaerobic tholin-using bacteria were isolated from common soil collected outside the laboratory building. Some, but not all, of the strains that were able to obtain carbon from tholin were also able to obtain their nitrogen requirements from tholin. Bacteria isolated from common soils were tested for their ability to obtain carbon from the water-soluble fraction, the ethanol-soluble fraction, and the water/ethanol-insoluble fraction of the tholin. Of the 3.5 × 10 7 bacteria isolated per gram of common soils, 1.7 0.5, and 0.2%, respectively, were able to obtaib their carbon requirements from the water-soluble fraction, the ethanol-soluble fraction and the water/ethanol-insoluble fraction of the tholin. The palatability of tholins to modern microbes may have implications for the early evolution of microbial life on Earth. Tholins may have formed the base of the food chain for an early heterotrophic biosphere before the evolution of autotrophy on the early Earth. Where tholins are present on other planets, they could possibly be metabolized by contaminant microorganisms transported to these bodies via spacecraft. Thus, the presence of tholins should be taken into account when evaluating the planetary quarantine requirements for probes to other planets.

Microbial production of multi-carbon chemicals and fuels from water and carbon dioxide using electric current

DOEpatents

Lovley, Derek R; Nevin, Kelly

2015-11-03

The invention provides systems and methods for generating organic compounds using carbon dioxide as a source of carbon and electrical current as an energy source. In one embodiment, a reaction cell is provided having a cathode electrode and an anode electrode that are connected to a source of electrical power, and which are separated by a permeable membrane. A biological film is provided on the cathode. The biological film comprises a bacterium that can accept electrons and that can convert carbon dioxide to a carbon-bearing compound and water in a cathode half-reaction. At the anode, water is decomposed to free molecular oxygen and solvated protons in an anode half-reaction. The half-reactions are driven by the application of electrical current from an external source. Compounds that have been produced include acetate, butanol, 2-oxobutyrate, propanol, ethanol, and formate.

Microbial production of multi-carbon chemicals and fuels from water and carbon dioxide using electric current

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lovley, Derek R.; Nevin, Kelly P.

The invention provides systems and methods for generating organic compounds using carbon dioxide as a source of carbon and electrical current as an energy source. In one embodiment, a reaction cell is provided having a cathode electrode and an anode electrode that are connected to a source of electrical power, and which are separated by a permeable membrane. A biological film is provided on the cathode. The biological film comprises a bacterium that can accept electrons and that can convert carbon dioxide to a carbon-bearing compound and water in a cathode half-reaction. At the anode, water is decomposed to freemore » molecular oxygen and solvated protons in an anode half-reaction. The half-reactions are driven by the application of electrical current from an external source. Compounds that have been produced include acetate, butanol, 2-oxobutyrate, propanol, ethanol, and formate.« less

Complete genome sequence of a carbon monoxide-utilizing acetogen, Eubacterium limosum KIST612.

PubMed

Roh, Hanseong; Ko, Hyeok-Jin; Kim, Daehee; Choi, Dong Geon; Park, Shinyoung; Kim, Sujin; Chang, In Seop; Choi, In-Geol

2011-01-01

Eubacterium limosum KIST612 is an anaerobic acetogenic bacterium that uses CO as the sole carbon/energy source and produces acetate, butyrate, and ethanol. To evaluate its potential as a syngas microbial catalyst, we have sequenced the complete 4.3-Mb genome of E. limosum KIST612.

Enhanced Bio-Ethanol Production from Industrial Potato Waste by Statistical Medium Optimization.

PubMed

Izmirlioglu, Gulten; Demirci, Ali

2015-10-15

Industrial wastes are of great interest as a substrate in production of value-added products to reduce cost, while managing the waste economically and environmentally. Bio-ethanol production from industrial wastes has gained attention because of its abundance, availability, and rich carbon and nitrogen content. In this study, industrial potato waste was used as a carbon source and a medium was optimized for ethanol production by using statistical designs. The effect of various medium components on ethanol production was evaluated. Yeast extract, malt extract, and MgSO₄·7H₂O showed significantly positive effects, whereas KH₂PO₄ and CaCl₂·2H₂O had a significantly negative effect (p-value<0.05). Using response surface methodology, a medium consisting of 40.4 g/L (dry basis) industrial waste potato, 50 g/L malt extract, and 4.84 g/L MgSO₄·7H₂O was found optimal and yielded 24.6 g/L ethanol at 30 °C, 150 rpm, and 48 h of fermentation. In conclusion, this study demonstrated that industrial potato waste can be used effectively to enhance bioethanol production.

Metabolic engineering of Synechocystis sp. PCC 6803 for enhanced ethanol production based on flux balance analysis.

PubMed

Yoshikawa, Katsunori; Toya, Yoshihiro; Shimizu, Hiroshi

2017-05-01

Synechocystis sp. PCC 6803 is an attractive host for bio-ethanol production due to its ability to directly convert atmospheric carbon dioxide into ethanol using photosystems. To enhance ethanol production in Synechocystis sp. PCC 6803, metabolic engineering was performed based on in silico simulations, using the genome-scale metabolic model. Comprehensive reaction knockout simulations by flux balance analysis predicted that the knockout of NAD(P)H dehydrogenase enhanced ethanol production under photoautotrophic conditions, where ammonium is the nitrogen source. This deletion inhibits the re-oxidation of NAD(P)H, which is generated by ferredoxin-NADP + reductase and imposes re-oxidation in the ethanol synthesis pathway. The effect of deleting the ndhF1 gene, which encodes NADH dehydrogenase subunit 5, on ethanol production was experimentally evaluated using ethanol-producing strains of Synechocystis sp. PCC 6803. The ethanol titer of the ethanol-producing ∆ndhF1 strain increased by 145%, compared with that of the control strain.

Green preparation of carbon dots with papaya as carbon source for effective fluorescent sensing of Iron (III) and Escherichia coli.

PubMed

Wang, Ning; Wang, Yiting; Guo, Tingting; Yang, Ting; Chen, Mingli; Wang, Jianhua

2016-11-15

A simple one-step hydrothermal green approach was reported for the preparation of carbon dots (CDs) without any further decoration or modification with papaya powder as natural carbon source. In this economical and eco-friendly system, deionized water or 90% ethanol was used as solvent to produce water-soluble or ethanol-soluble CDs, respectively, termed as W-CDs and E-CDs. The quantum yield (QY) for W-CDs was 18.98%, while that for E-CDs was 18.39%. The potentials of the prepared carbon dots toward diverse applications were thoroughly investigated. W-CDs and E-CDs provide promising probes for fluorescence detection of Fe(3+), offering limits of detection of 0.48μmolL(-1) and 0.29μmolL(-1), respectively. W-CDs was further demonstrated to be a promising probe for fluorescence sensing of Escherichia coli O157: H7, along with a limit of detection of 9.5×10(4)cfumL(-1). Meanwhile, both W-CDs and E-CDs exhibit favorable biocompatibility, and demonstrated to be efficient for Hela cell imaging. Copyright © 2016 Elsevier B.V. All rights reserved.

Microbial degradation of parathion. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Gibson, W. L.

1972-01-01

An organism capable of utilizing parathion as the sole carbon and energy source was isolated by enrichment culture techniques. The bacterium was characterized and tentatively classified as Pseudomonas aeruginosa. A pH of 7.0 - 7.5 and temperature of 30 C were found to be optimum for the consumption of parathion. Virtually no oxygen utilization was observed with resting cell suspensions when nonsolubilized parathion was employed. The use of ethanol as solvent for parathion in resting cell studies or preincubation of cells in ethanol obviated this problem and rapid parathion oxidation was demonstrable. Approximately 80% of the parathion consumed by resting cells was present terminally as carbon dioxide. Permeability of the cell to parathion or its metabolites was contingent upon the use of ethanol as either solvent or denaturant. Metabolites were tentatively identified by thin layer chromatography.

Applying Adaptive Agricultural Management & Industrial Ecology Principles to Produce Lower- Carbon Ethanol from California Energy Beets

NASA Astrophysics Data System (ADS)

Alexiades, Anthy Maria

The life cycle assessment of a proposed beet-to-ethanol pathway demonstrates how agricultural management and industrial ecology principles can be applied to reduce greenhouse gas emissions, minimize agrochemical inputs and waste, provide ecosystem services and yield a lower-carbon fuel from a highly land-use efficient, first-generation feedstock cultivated in California. Beets grown in California have unique potential as a biofuel feedstock. A mature agricultural product with well-developed supply chains, beet-sugar production in California has contracted over recent decades, leaving idle production capacity and forcing growers to seek other crops for use in rotation or find a new market for beets. California's Low Carbon Fuel Standard (LCFS) faces risk of steeply-rising compliance costs, as greenhouse gas reduction targets in the transportation sector were established assuming commercial volumes of lower-carbon fuels from second-generation feedstocks -- such as residues, waste, algae and cellulosic crops -- would be available by 2020. The expected shortfall of cellulosic ethanol has created an immediate need to develop lower-carbon fuels from readily available feedstocks using conventional conversion technologies. The life cycle carbon intensity of this ethanol pathway is less than 28 gCO2e/MJEthanol: a 72% reduction compared to gasoline and 19% lower than the most efficient corn ethanol pathway (34 gCO2e/MJ not including indirect land use change) approved under LCFS. The system relies primarily on waste-to-energy resources; nearly 18 gCO2e/MJ are avoided by using renewable heat and power generated from anaerobic digestion of fermentation stillage and gasification of orchard residues to meet 88% of the facility's steam demand. Co-products displace 2 gCO2e/MJ. Beet cultivation is the largest source of emissions, contributing 15 gCO 2e/MJ. The goal of the study is to explore opportunities to minimize carbon intensity of beet-ethanol and investigate the potential contribution of this pathway toward meeting the near-term objectives of California's climate change policy.

Carbon membranes for efficient water-ethanol separation.

PubMed

Gravelle, Simon; Yoshida, Hiroaki; Joly, Laurent; Ybert, Christophe; Bocquet, Lydéric

2016-09-28

We demonstrate, on the basis of molecular dynamics simulations, the possibility of an efficient water-ethanol separation using nanoporous carbon membranes, namely, carbon nanotube membranes, nanoporous graphene sheets, and multilayer graphene membranes. While these carbon membranes are in general permeable to both pure liquids, they exhibit a counter-intuitive "self-semi-permeability" to water in the presence of water-ethanol mixtures. This originates in a preferred ethanol adsorption in nanoconfinement that prevents water molecules from entering the carbon nanopores. An osmotic pressure is accordingly expressed across the carbon membranes for the water-ethanol mixture, which agrees with the classic van't Hoff type expression. This suggests a robust and versatile membrane-based separation, built on a pressure-driven reverse-osmosis process across these carbon-based membranes. In particular, the recent development of large-scale "graphene-oxide" like membranes then opens an avenue for a versatile and efficient ethanol dehydration using this separation process, with possible application for bio-ethanol fabrication.

Carbon membranes for efficient water-ethanol separation

NASA Astrophysics Data System (ADS)

Gravelle, Simon; Yoshida, Hiroaki; Joly, Laurent; Ybert, Christophe; Bocquet, Lydéric

2016-09-01

We demonstrate, on the basis of molecular dynamics simulations, the possibility of an efficient water-ethanol separation using nanoporous carbon membranes, namely, carbon nanotube membranes, nanoporous graphene sheets, and multilayer graphene membranes. While these carbon membranes are in general permeable to both pure liquids, they exhibit a counter-intuitive "self-semi-permeability" to water in the presence of water-ethanol mixtures. This originates in a preferred ethanol adsorption in nanoconfinement that prevents water molecules from entering the carbon nanopores. An osmotic pressure is accordingly expressed across the carbon membranes for the water-ethanol mixture, which agrees with the classic van't Hoff type expression. This suggests a robust and versatile membrane-based separation, built on a pressure-driven reverse-osmosis process across these carbon-based membranes. In particular, the recent development of large-scale "graphene-oxide" like membranes then opens an avenue for a versatile and efficient ethanol dehydration using this separation process, with possible application for bio-ethanol fabrication.

Regulation of phosphoenolpyruvate carboxykinase and pyruvate kinase in Saccharomyces cerevisiae grown in the presence of glycolytic and gluconeogenic carbon sources and the role of mitochondrial function on gluconeogenesis.

PubMed

Wilson, A J; Bhattacharjee, J K

1986-12-01

Phosphoenolpyruvate carboxykinase (PEPCKase) and pyruvate kinase (PKase) were measured in Saccharomyces cerevisiae grown in the presence of glycolytic and gluconeogenic carbon sources. The PEPCKase activity was highest in ethanol-grown cells. However, high PEPCKase activity was also observed in cells grown in 1% glucose, especially as compared with the activity of sucrose-, maltose-, or galactose-grown cells. Activity was first detected after 12 h when glucose was exhausted from the growth medium. The PKase activity was very high in glucose-grown cells; considerable activity was also present in ethanol- and pyruvate-grown cells. The absolute requirement of respiration for gluconeogenesis was demonstrated by the absence or significantly low levels of PEPCKase and fructose-1,6-bisphosphatase activities observed in respiratory deficient mutants, as well as in wild-type S. cerevisiae cells grown in the presence of glucose and antimycin A or chloramphenicol. Obligate glycolytic and gluconeogenic enzymes were present simultaneously only in stationary phase cells, but not in exponential phase cells; hence futile cycling could not occur in log phase cells regardless of the presence of carbon source in the growth medium.

Soil carbon and nitrogen fractions under biofuel cropping in the Piedmont of North Carolina

USDA-ARS?s Scientific Manuscript database

As our country considers new sources of energy, biofuel crops are a source that is ever-present in that conversation. These “energy canes” can be used for heat and electricity generation, for production of fiber composite products, feed for livestock, and fuelstock for ethanol production. Our resear...

Recovery of low-temperature stressed E. coli O157:H7 and its susceptibility to crystal violet, bile salt, sodium chloride and ethanol.

PubMed

Chou, C C; Cheng, S J

2000-11-01

This study was conducted to investigate the alteration of some characteristics of E. coli O157:H7 subjected to various periods of storage at -5, -18 and -28 degrees C. Results revealed that the low-temperature treatments increased the susceptibility of E. coli O157:H7 to crystal violet, bile salt, sodium chloride and ethanol. In general, the susceptibility of E. coli O157:H7 subjected to storage at -18 degrees C increased most significantly. The susceptibility of E. coli O157:H7 to the tested agents increased as the period of low-temperature storage extended, regardless of storage temperature. Among the various nitrogen and carbon sources tested, tryptone and soytone were the most effective nitrogen sources, while glucose and maltose were the most effective carbon sources for the growth of the low-temperature stressed cells. When growing the stressed E. coli O157:H7 in media containing the same nitrogen source or carbon source, their lag period increased as the time of frozen storage increased. It was also noted that in general, the recovery of the low-temperature stressed E. coli O157:H7 was highest on tryptic soy agar followed by Modified eosin methylene blue agar, while recovery on MaConkey sorbitol agar and Modified MaConkey sorbitol agar was lowest.

Study toward high-performance thermally driven air-conditioning systems

NASA Astrophysics Data System (ADS)

Miyazaki, Takahiko; Miyawaki, Jin; Ohba, Tomonori; Yoon, Seong-Ho; Saha, Bidyut Baran; Koyama, Shigeru

2017-01-01

The Adsorption heat pump is a technology for cooling and heating by using hot water as a driving heat source. It will largely contribute to energy savings when it is driven by solar thermal energy or waste heat. The system is available in the market worldwide, and there are many examples of application to heat recovery in factories and to solar cooling systems. In the present system, silica gel and zeolite are popular adsorbents in combination with water refrigerant. Our study focused on activated carbon-ethanol pair for adsorption cooling system because of the potential to compete with conventional systems in terms of coefficient of performance. In addition, activated-ethanol pair can generally produce larger cooling effect by an adsorption-desorption cycle compared with that of the conventional pairs in terms of cooling effect per unit adsorbent mass. After the potential of a commercially available activated carbon with highest level specific surface area was evaluated, we developed a new activated carbon that has the optimum pore characteristics for the purpose of solar or waste heat driven cooling systems. In this paper, comparison of refrigerants for adsorption heat pump application is presented, and a newly developed activated carbon for ethanol adsorption heat pump is introduced.

Enhanced Bio-Ethanol Production from Industrial Potato Waste by Statistical Medium Optimization

PubMed Central

Izmirlioglu, Gulten; Demirci, Ali

2015-01-01

Industrial wastes are of great interest as a substrate in production of value-added products to reduce cost, while managing the waste economically and environmentally. Bio-ethanol production from industrial wastes has gained attention because of its abundance, availability, and rich carbon and nitrogen content. In this study, industrial potato waste was used as a carbon source and a medium was optimized for ethanol production by using statistical designs. The effect of various medium components on ethanol production was evaluated. Yeast extract, malt extract, and MgSO4·7H2O showed significantly positive effects, whereas KH2PO4 and CaCl2·2H2O had a significantly negative effect (p-value < 0.05). Using response surface methodology, a medium consisting of 40.4 g/L (dry basis) industrial waste potato, 50 g/L malt extract, and 4.84 g/L MgSO4·7H2O was found optimal and yielded 24.6 g/L ethanol at 30 °C, 150 rpm, and 48 h of fermentation. In conclusion, this study demonstrated that industrial potato waste can be used effectively to enhance bioethanol production. PMID:26501261

Characterizing model uncertainties in the life cycle of lignocellulose-based ethanol fuels.

PubMed

Spatari, Sabrina; MacLean, Heather L

2010-11-15

Renewable and low carbon fuel standards being developed at federal and state levels require an estimation of the life cycle carbon intensity (LCCI) of candidate fuels that can substitute for gasoline, such as second generation bioethanol. Estimating the LCCI of such fuels with a high degree of confidence requires the use of probabilistic methods to account for known sources of uncertainty. We construct life cycle models for the bioconversion of agricultural residue (corn stover) and energy crops (switchgrass) and explicitly examine uncertainty using Monte Carlo simulation. Using statistical methods to identify significant model variables from public data sets and Aspen Plus chemical process models,we estimate stochastic life cycle greenhouse gas (GHG) emissions for the two feedstocks combined with two promising fuel conversion technologies. The approach can be generalized to other biofuel systems. Our results show potentially high and uncertain GHG emissions for switchgrass-ethanol due to uncertain CO₂ flux from land use change and N₂O flux from N fertilizer. However, corn stover-ethanol,with its low-in-magnitude, tight-in-spread LCCI distribution, shows considerable promise for reducing life cycle GHG emissions relative to gasoline and corn-ethanol. Coproducts are important for reducing the LCCI of all ethanol fuels we examine.

N2O production in the Fe(II)(EDTA)-NO reduction process: the effects of carbon source and pH.

PubMed

Chen, Jun; Wang, Lei; Zheng, Ji; Chen, Jianmeng

2015-07-01

Chemical absorption-biological reduction (BioDeNOx), which uses Fe(II)(EDTA) as a complexing agent for promoting the mass transfer efficiency of NO from gas to water, is a promising technology for removing nitric oxide (NO) from flue gases. The carbon source and pH are important parameters for Fe(II)(EDTA)-NO (the production of absorption) reduction and N2O emissions from BioDeNOx systems. Batch tests were performed to evaluate the effects of four different carbon sources (i.e., methanol, ethanol, sodium acetate, and glucose) on Fe(II)(EDTA)-NO reduction and N2O emissions at an initial pH of 7.2 ± 0.2. The removal efficiency of Fe(II)(EDTA)-NO was 93.9%, with a theoretical rate of 0.77 mmol L(-1) h(-1) after 24 h of operation. The highest N2O production was 0.025 mmol L(-1) after 3 h when glucose was used as the carbon source. The capacities of the carbon sources to enhance the activity of the Fe(II)(EDTA)-NO reductase enzyme decreased in the following order based on the C/N ratio: glucose > ethanol > sodium acetate > methanol. Over the investigated pH range of 5.5-8.5, the Fe(II)(EDTA)-NO removal efficiency was highest at a pH of 7.5, with a theoretical rate of 0.88 mmol L(-1) h(-1). However, the N2O production was lowest at a pH of 8.5. The primary effect of pH on denitrification resulted from the inhibition of nosZ in acidic conditions.

Role of the glyoxylate pathway in acetic acid production by Acetobacter aceti.

PubMed

Sakurai, Kenta; Yamazaki, Shoko; Ishii, Masaharu; Igarashi, Yasuo; Arai, Hiroyuki

2013-01-01

Wild-type Acetobacter aceti NBRC 14818 possesses genes encoding isocitrate lyase (aceA) and malate synthase (glcB), which constitute the glyoxylate pathway. In contrast, several acetic acid bacteria that are utilized for vinegar production lack these genes. Here, an aceA-glcB knockout mutant of NBRC 14818 was constructed and used for investigating the role of the glyoxylate pathway in acetate productivity. In medium containing ethanol as a carbon source, the mutant grew normally during ethanol oxidation to acetate, but exhibited slower growth than that of the wild-type strain as the accumulated acetate was oxidized. The mutant grew similarly to that of the wild-type strain in medium containing glucose as a carbon source, indicating that the glyoxylate pathway was not necessary for glucose utilization. However, in medium containing both ethanol and glucose, the mutant exhibited significantly poorer growth and lower glucose consumption compared to the wild-type strain. Notably, the mutant oxidized ethanol nearly stoichiometrically to acetate, which was retained in the medium for a longer period of time than the acetate produced by wild-type strain. The features of the aceA-glcB knockout mutant revealed here indicate that the lack of the glyoxylate pathway is advantageous for industrial vinegar production by A. aceti. Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Stable bioemulsifiers are produced by Acinetobacter bouvetii UAM25 growing in different carbon sources.

PubMed

Ortega-de la Rosa, Nestor D; Vázquez-Vázquez, Jose L; Huerta-Ochoa, Sergio; Gimeno, Miquel; Gutiérrez-Rojas, Mariano

2018-06-01

Acinetobacter species are identified as producing surface-active and emulsifying molecules known as bioemulsifiers. Production, characterization and stability of bioemulsifiers produced by Acinetobacter bouvetii UAM25 were studied. A. bouvetii UAM25 grew in three different carbon and energy sources: ethanol, a glycerol-hexadecane mixture and waste cooking oil in an airlift bioreactor, showing that bioemulsifier production was growth associated. The three purified bioemulsifiers were lipo-heteropolysaccharides of high molecular weight (4866 ± 533 and 462 ± 101 kDa). The best carbon source and energy for bioemulsifier production was wasted cooking oil, with a highest emulsifying capacity (76.2 ± 3.5 EU mg -1 ) as compared with ethanol (46.6 ± 7.1 EU mg -1 ) and the glycerol-hexadecane mixture (49.5 ± 4.2 EU mg -1 ). The three bioemulsifiers in our study displayed similar macromolecular structures, regardless of the nature (hydrophobic or hydrophilic) of the carbon and energy source. Bioemulsifiers did not decrease surface tension, but the emulsifying capacity of all of them was retained under extreme variation in salinity (0-50 g NaCl L -1 ), pH (3-10) and temperature (25-121 °C), indicative of remarkable stability. These findings contribute to understanding of the relationship between: production, physical properties, chemical composition and stability of bioemulsifiers for their potential applications in biotechnology, such as bioremediation of hydrocarbon-contaminated soil and water.

Land-use and alternative bioenergy pathways for waste biomass.

PubMed

Campbell, J E; Block, E

2010-11-15

Rapid escalation in biofuels consumption may lead to a trade regime that favors exports of food-based biofuels from tropical developing countries to developed countries. There is growing interest in mitigating the land-use impacts of these potential biofuels exports by converting biorefinery waste streams into cellulosic ethanol, potentially reducing the amount of land needed to meet production goals. This increased land-use efficiency for ethanol production may lower the land-use greenhouse gas emissions of ethanol but would come at the expense of converting the wastes into bioelectricity which may offset fossil fuel-based electricity and could provide a vital source of domestic electricity in developing countries. Here we compare these alternative uses of wastes with respect to environmental and energy security outcomes considering a range of electricity production efficiencies, ethanol yields, land-use scenarios, and energy offset assumptions. For a given amount of waste biomass, we found that using bioelectricity production to offset natural gas achieves 58% greater greenhouse gas reductions than using cellulosic ethanol to offset gasoline but similar emissions when cellulosic ethanol is used to offset the need for more sugar cane ethanol. If bioelectricity offsets low-carbon energy sources such as nuclear power then the liquid fuels pathway is preferred. Exports of cellulosic ethanol may have a small impact on the energy security of importing nations while bioelectricity production may have relatively large impacts on the energy security in developing countries.

Evaluation of gasoline-denatured ethanol as a carbon source for denitrification.

PubMed

Kazasi, Anna; Boardman, Gregory D; Bott, Charles B

2013-06-01

In this study concerning denitrification, the performance of three carbon sources, methanol (MeOH), ethanol (EtOH) and gasoline-denatured ethanol (dEtOH), was compared and evaluated on the basis of treatment efficiency, inhibition potential and cost. The gasoline denaturant considered here contained mostly aliphatic compounds and little of the components that typically boost the octane rating, such as benzene, toluene, ethylbenzene and xylenes. Results were obtained using three lab-scale SBRs operated at SRT of 12.0 +/- 0.9 days. After biomass was acclimated, denitrification rates with dEtOH were similar to those of EtOH (201 +/- 50 and 197 +/- 28 NO3-N/g MLVSS x d, respectively), and higher than those of MeOH (165 +/- 49 mg NO3-N/g MLVSS x d). The denaturant did not affect biomass production, nitrification or denitrification. Effluent soluble COD concentrations were always less than the analytical detection limit. Although the cost of dEtOH ($2.00/kg nitrate removed) was somewhat higher than that of methanol ($1.63/kg nitrate removed), the use of dEtOH is very promising and utilities will have to decide if it is worth paying a little extra to take advantage of its benefits.

The preparation and ethanol fermentation of high-concentration sugars from steam-explosion corn stover.

PubMed

Xie, Hui; Wang, Fengqin; Yin, Shuangyao; Ren, Tianbao; Song, Andong

2015-05-01

In the field of biofuel ethanol, high-concentration- reducing sugars made from cellulosic materials lay the foundation for high-concentration ethanol fermentation. In this study, corn stover was pre-treated in a process combining chemical methods and steam explosion; the cellulosic hydrolyzed sugars obtained by fed-batch saccharification were then used as the carbon source for high-concentration ethanol fermentation. Saccharomyces cerevisiae 1308, Angel yeast, and Issatchenkia orientalis were shake-cultured with Pachysolen tannophilus P-01 for fermentation. Results implied that the ethanol yields from the three types of mixed strains were 4.85 g/100 mL, 4.57 g/100 mL, and 5.02 g/100 mL (separately) at yield rates of 91.6, 89.3, and 92.2%, respectively. Therefore, it was inferred that shock-fermentation using mixed strains achieved a higher ethanol yield at a greater rate in a shorter fermentation period. This study provided a theoretical basis and technical guidance for the fermentation of industrial high-concentrated cellulosic ethanol.

Ethanol and Acetic Acid Production from Carbon Monoxide in a Clostridium Strain in Batch and Continuous Gas-Fed Bioreactors

PubMed Central

Nalakath Abubackar, Haris; Veiga, María C.; Kennes, Christian

2015-01-01

The effect of different sources of nitrogen as well as their concentrations on the bioconversion of carbon monoxide to metabolic products such as acetic acid and ethanol by Clostridium autoethanogenum was studied. In a first set of assays, under batch conditions, either NH4Cl, trypticase soy broth or yeast extract (YE) were used as sources of nitrogen. The use of YE was found statistically significant (p < 0.05) on the product spectrum in such batch assays. In another set of experiments, three bioreactors were operated with continuous CO supply, in order to estimate the effect of running conditions on products and biomass formation. The bioreactors were operated under different conditions, i.e., EXP1 (pH = 5.75, YE 1g/L), EXP2 (pH = 4.75, YE 1 g/L) and EXP3 (pH = 5.75, YE 0.2 g/L). When compared to EXP2 and EXP3, it was found that EXP1 yielded the maximum biomass accumulation (302.4 mg/L) and products concentrations, i.e., acetic acid (2147.1 mg/L) and ethanol (352.6 mg/L). This can be attributed to the fact that the higher pH and higher YE concentration used in EXP1 stimulated cell growth and did, consequently, also enhance metabolite production. However, when ethanol is the desired end-product, as a biofuel, the lower pH used in EXP2 was more favourable for solventogenesis and yielded the highest ethanol/acetic acid ratio, reaching a value of 0.54. PMID:25608591

Ethanol and acetic acid production from carbon monoxide in a Clostridium strain in batch and continuous gas-fed bioreactors.

PubMed

Abubackar, Haris Nalakath; Veiga, María C; Kennes, Christian

2015-01-20

The effect of different sources of nitrogen as well as their concentrations on the bioconversion of carbon monoxide to metabolic products such as acetic acid and ethanol by Clostridium autoethanogenum was studied. In a first set of assays, under batch conditions, either NH4Cl, trypticase soy broth or yeast extract (YE) were used as sources of nitrogen. The use of YE was found statistically significant (p < 0.05) on the product spectrum in such batch assays. In another set of experiments, three bioreactors were operated with continuous CO supply, in order to estimate the effect of running conditions on products and biomass formation. The bioreactors were operated under different conditions, i.e., EXP1 (pH = 5.75, YE 1g/L), EXP2 (pH = 4.75, YE 1 g/L) and EXP3 (pH = 5.75, YE 0.2 g/L). When compared to EXP2 and EXP3, it was found that EXP1 yielded the maximum biomass accumulation (302.4 mg/L) and products concentrations, i.e., acetic acid (2147.1 mg/L) and ethanol (352.6 mg/L). This can be attributed to the fact that the higher pH and higher YE concentration used in EXP1 stimulated cell growth and did, consequently, also enhance metabolite production. However, when ethanol is the desired end-product, as a biofuel, the lower pH used in EXP2 was more favourable for solventogenesis and yielded the highest ethanol/acetic acid ratio, reaching a value of 0.54.

Rice bran extract: an inexpensive nitrogen source for the production of 2G ethanol from sugarcane bagasse hydrolysate.

PubMed

Milessi, Thais S S; Antunes, Felipe A F; Chandel, Anuj K; Silva, Silvio S

2013-10-01

Selection of the raw material and its efficient utilization are the critical factors in economization of second generation (2G) ethanol production. Fermentation of the released sugars into ethanol by a suitable ethanol producing microorganism using cheap media ingredients is the cornerstone of the overall process. This study evaluated the potential of rice bran extract (RBE) as a cheap nitrogen source for the production of 2G ethanol by Scheffersomyces (Pichia) stipitis NRRL Y-7124 using sugarcane bagasse (SB) hemicellulosic hydrolysate. Dilute acid hydrolysis of SB showed 12.45 g/l of xylose and 0.67 g/l of glucose along with inhibitors. It was concentrated by vacuum evaporation and submitted to sequential detoxification (neutralization by calcium hydroxide and charcoal adsorption). The detoxified hydrolysate revealed the removal of furfural (81 %) and 5-hydroxymethylfurfural (61 %) leading to the final concentration of glucose (1.69 g/l) and xylose (33.03 g/l). S. stipitis was grown in three different fermentation media composed of detoxified hydrolysate as carbon source supplemented with varying nitrogen sources i.e. medium #1 (RBE + ammonium sulfate + calcium chloride), medium #2 (yeast extract + peptone) and medium #3 (yeast extract + peptone + malt extract). Medium #1 showed maximum ethanol production (8.6 g/l, yield 0.22 g/g) followed by medium #2 (8.1 g/l, yield 0.19 g/g) and medium #3 (7.4 g/l, yield 0.18 g/g).

Life cycle assessment of fuel ethanol derived from corn grain via dry milling.

PubMed

Kim, Seungdo; Dale, Bruce E

2008-08-01

Life cycle analysis enables to investigate environmental performance of fuel ethanol used in an E10 fueled compact passenger vehicle. Ethanol is derived from corn grain via dry milling. This type of analysis is an important component for identifying practices that will help to ensure that a renewable fuel, such as ethanol, may be produced in a sustainable manner. Based on data from eight counties in seven Corn Belt states as corn farming sites, we show ethanol derived from corn grain as E10 fuel would reduce nonrenewable energy and greenhouse gas emissions, but would increase acidification, eutrophication and photochemical smog, compared to using gasoline as liquid fuel. The ethanol fuel systems considered in this study offer economic benefits, namely more money returned to society than the investment for producing ethanol. The environmental performance of ethanol fuel system varies significantly with corn farming sites because of different crop management practices, soil properties, and climatic conditions. The dominant factor determining most environmental impacts considered here (i.e., greenhouse gas emissions, acidification, eutrophication, and photochemical smog formation) is soil related nitrogen losses (e.g., N2O, NOx, and NO3-). The sources of soil nitrogen include nitrogen fertilizer, crop residues, and air deposition. Nitrogen fertilizer is probably the primary source. Simulations using an agro-ecosystem model predict that planting winter cover crops would reduce soil nitrogen losses and increase soil organic carbon levels, thereby greatly improving the environmental performance of the ethanol fuel system.

Pilot-scale conversion of lime-treated wheat straw into bioethanol: quality assessment of bioethanol and valorization of side streams by anaerobic digestion and combustion

PubMed Central

Maas, Ronald HW; Bakker, Robert R; Boersma, Arjen R; Bisschops, Iemke; Pels, Jan R; de Jong, Ed; Weusthuis, Ruud A; Reith, Hans

2008-01-01

Introduction The limited availability of fossil fuel sources, worldwide rising energy demands and anticipated climate changes attributed to an increase of greenhouse gasses are important driving forces for finding alternative energy sources. One approach to meeting the increasing energy demands and reduction of greenhouse gas emissions is by large-scale substitution of petrochemically derived transport fuels by the use of carbon dioxide-neutral biofuels, such as ethanol derived from lignocellulosic material. Results This paper describes an integrated pilot-scale process where lime-treated wheat straw with a high dry-matter content (around 35% by weight) is converted to ethanol via simultaneous saccharification and fermentation by commercial hydrolytic enzymes and bakers' yeast (Saccharomyces cerevisiae). After 53 hours of incubation, an ethanol concentration of 21.4 g/liter was detected, corresponding to a 48% glucan-to-ethanol conversion of the theoretical maximum. The xylan fraction remained mostly in the soluble oligomeric form (52%) in the fermentation broth, probably due to the inability of this yeast to convert pentoses. A preliminary assessment of the distilled ethanol quality showed that it meets transportation ethanol fuel specifications. The distillation residue, which contained non-hydrolysable and non-fermentable (in)organic compounds, was divided into a liquid and solid fraction. The liquid fraction served as substrate for the production of biogas (methane), whereas the solid fraction functioned as fuel for thermal conversion (combustion), yielding thermal energy, which can be used for heat and power generation. Conclusion Based on the achieved experimental values, 16.7 kg of pretreated wheat straw could be converted to 1.7 kg of ethanol, 1.1 kg of methane, 4.1 kg of carbon dioxide, around 3.4 kg of compost and 6.6 kg of lignin-rich residue. The higher heating value of the lignin-rich residue was 13.4 MJ thermal energy per kilogram (dry basis). PMID:18699996

L-Lactic acid production from glycerol coupled with acetic acid metabolism by Enterococcus faecalis without carbon loss.

PubMed

Murakami, Nao; Oba, Mana; Iwamoto, Mariko; Tashiro, Yukihiro; Noguchi, Takuya; Bonkohara, Kaori; Abdel-Rahman, Mohamed Ali; Zendo, Takeshi; Shimoda, Mitsuya; Sakai, Kenji; Sonomoto, Kenji

2016-01-01

Glycerol is a by-product in the biodiesel production process and considered as one of the prospective carbon sources for microbial fermentation including lactic acid fermentation, which has received considerable interest due to its potential application. Enterococcus faecalis isolated in our laboratory produced optically pure L-lactic acid from glycerol in the presence of acetic acid. Gas chromatography-mass spectrometry analysis using [1, 2-(13)C2] acetic acid proved that the E. faecalis strain QU 11 was capable of converting acetic acid to ethanol during lactic acid fermentation of glycerol. This indicated that strain QU 11 restored the redox balance by oxidizing excess NADH though acetic acid metabolism, during ethanol production, which resulted in lactic acid production from glycerol. The effects of pH control and substrate concentration on lactic acid fermentation were also investigated. Glycerol and acetic acid concentrations of 30 g/L and 10 g/L, respectively, were expected to be appropriate for lactic acid fermentation of glycerol by strain QU 11 at a pH of 6.5. Furthermore, fed-batch fermentation with 30 g/L glycerol and 10 g/L acetic acid wholly exhibited the best performance including lactic acid production (55.3 g/L), lactic acid yield (0.991 mol-lactic acid/mol-glycerol), total yield [1.08 mol-(lactic acid and ethanol)]/mol-(glycerol and acetic acid)], and total carbon yield [1.06 C-mol-(lactic acid and ethanol)/C-mol-(glycerol and acetic acid)] of lactic acid and ethanol. In summary, the strain QU 11 successfully produced lactic acid from glycerol with acetic acid metabolism, and an efficient fermentation system was established without carbon loss. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Increased ethanol production by deletion of HAP4 in recombinant xylose-assimilating Saccharomyces cerevisiae.

PubMed

Matsushika, Akinori; Hoshino, Tamotsu

2015-12-01

The Saccharomyces cerevisiae HAP4 gene encodes a transcription activator that plays a key role in controlling the expression of genes involved in mitochondrial respiration and reductive pathways. This work examines the effect of knockout of the HAP4 gene on aerobic ethanol production in a xylose-utilizing S. cerevisiae strain. A hap4-deleted recombinant yeast strain (B42-DHAP4) showed increased maximum concentration, production rate, and yield of ethanol compared with the reference strain MA-B42, irrespective of cultivation medium (glucose, xylose, or glucose/xylose mixtures). Notably, B42-DHAP4 was capable of producing ethanol from xylose as the sole carbon source under aerobic conditions, whereas no ethanol was produced by MA-B42. Moreover, the rate of ethanol production and ethanol yield (0.44 g/g) from the detoxified hydrolysate of wood chips was markedly improved in B42-DHAP4 compared to MA-B42. Thus, the results of this study support the view that deleting HAP4 in xylose-utilizing S. cerevisiae strains represents a useful strategy in ethanol production processes.

Nitrogen-doped mesoporous carbon-armored cobalt nanoparticles as efficient hydrogen evolving electrocatalysts.

PubMed

Tang, Duihai; Li, Kuo; Zhang, Wenting; Qiao, Zhen-An; Zhu, Junjiang; Zhao, Zhen

2018-03-15

A series of Co nanoparticles embedded, N-doped mesoporous carbons have been synthesized through chelate-assisted co-assembly strategy followed by thermal treatment. The preparation is based on an assembly process, with evaporation of an ethanol-water solution containing melamine formaldehyde resin (MF resin) as carbon source, nitrogen source, and chelating agent. Moreover, F127 and Co(NO 3 ) 2 are used as template and metallic precursor, respectively. The Co nanoparticles embedded, N-doped mesoporous carbon annealed at 800 °C (denoted as MFCo800) shows high electrocatalytic activity for hydrogen evolution reaction (HER) with high current density and low overpotential, which has the ability to operate in both acidic and alkaline electrolytes. Copyright © 2017. Published by Elsevier Inc.

Production of fuel ethanol from cellulosic peat for future transportation systems.

DOT National Transportation Integrated Search

2007-12-01

The production of bioethanol from peat is proposed. A search of the available : literature yields no prior information on the use of peat as a carbon source for : bioethanol. This proposal addresses the production in the most cost-effective manner : ...

Influence of electron donors and copper concentration on geochemical and mineralogical processes under conditions of biological sulphate reduction

NASA Astrophysics Data System (ADS)

Wolicka, Dorota; Borkowski, Andrzej

2014-03-01

Sulphidogenous microorganism communities were isolated from soil polluted by crude oil. The study was focused on determining the influence of 1) copper (II) concentration on the activity of selected microorganism communities and 2) the applied electron donor on the course and evolution of mineral-forming processes under conditions favouring growth of sulphate-reducing bacteria (SRB). The influence of copper concentration on the activity of selected microorganism communities and the type of mineral phases formed was determined during experiments in which copper (II) chloride at concentrations of 0.1, 0.2, 0.5 and 0.7 g/L was added to SRB cultures. The experiments were performed in two variants: with ethanol (4 g/L) or lactate (4 g/L) as the sole carbon source. In order to determine the taxonomic composition of the selected microorganism communities, the 16S rRNA method was used. Results of this analysis confirmed the presence of Desulfovibrio, Desulfohalobium, Desulfotalea, Thermotoga, Solibacter, Gramella, Anaeromyxobacter and Myxococcus sp. in the stationary cultures. The post-culture sediments contained covelline (CuS) and digenite (Cu9S5 ). Based on the results, it can be stated that the type of carbon source applied during incubation plays a crucial role in determining the mineral composition of the post-culture sediments. Thus, regardless of the amount of copper ion introduced to a culture with lactate as the sole carbon source, no copper sulphide was observed in the post-culture sediments. Cultures with ethanol as the sole carbon source, on the other hand, yielded covelline or digenite in all post-culture sediments.

Carbon-dependent chromate toxicity mechanism in an environmental Arthrobacter isolate.

PubMed

Field, Erin K; Blaskovich, John P; Peyton, Brent M; Gerlach, Robin

2018-05-12

Arthrobacter spp. are widespread in soil systems and well-known for their Cr(VI) reduction capabilities making them attractive candidates for in situ bioremediation efforts. Cellulose drives carbon flow in soil systems; yet, most laboratory studies evaluate Arthrobacter-Cr(VI) interactions solely with nutrient-rich media or glucose. This study aims to determine how various cellulose degradation products and biostimulation substrates influence Cr(VI) toxicity, reduction, and microbial growth of an environmental Arthrobacter sp. isolate. Laboratory culture-based studies suggest there is a carbon-dependent Cr(VI) toxicity mechanism that affects subsequent Cr(VI) reduction by strain LLW01. Strain LLW01 could only grow in the presence of, and reduce, 50 μM Cr(VI) when glucose or lactate were provided. Compared to lactate, Cr(VI) was at least 30-fold and 10-fold more toxic when ethanol or butyrate was the sole carbon source, respectively. The addition of sulfate mitigated toxicity somewhat, but had no effect on the extent of Cr(VI) reduction. Cell viability studies indicated that a small fraction of cells were viable after 8 days suggesting cell growth and subsequent Cr(VI) reduction may resume. These results suggest when designing bioremediation strategies with Arthrobacter spp. such as strain LLW01, carbon sources such as glucose and lactate should be considered over ethanol and butyrate. Copyright © 2018 Elsevier B.V. All rights reserved.

The influence of different cultivation conditions on the metabolome of Fusarium oxysporum.

PubMed

Panagiotou, Gianni; Christakopoulos, Paul; Olsson, Lisbeth

2005-08-22

The two most widespread pentose sugars found in the biosphere are d-xylose and l-arabinose. They are both potential substrates for ethanol production. The purpose of this study was to better understand the redox constraints imposed to Fusarium oxysporum during utilization of pentoses. In order to increase ethanol yield and decrease by-product formation, nitrate was used as nitrogen source. The use of NADH, the cofactor in denitrification process when using nitrate as a nitrogen source, improved the ethanol yield on xylose to 0.89 mol mol(-1) compared to the ethanol yield achieved using ammonium as nitrogen source 0.44 mol mol(-1). The improved ethanol yield was followed by a 28% decrease in yield of the by-product xylitol. In order to investigate the metabolic pathway of arabinose and the metabolic limitations for the efficient ethanol production from this sugar, the extracellular and intracellular metabolite profiles were determined under aerobic and anaerobic cultivation conditions. The results of this study clearly show difficulties in channelling of glucose-1-P (G1P) to pentose phosphate pathway (PPP) and reduced NADPH regeneration, suggesting that NADPH becomes a limiting factor for arabinose conversion, resulting in excessive acetate production. Variations of the fungus intracellular amino and non-amino acid pool, under different culture conditions, were evaluated using principal component analysis (PCA). PCA projection of the metabolome data collected from F. oxysporum subjected to environmental perturbations succeeded to visualize different physiological states and the conclusions of this study were that the metabolite profile is unique according to: (1) the carbon source and (2) the oxygen supply, and to a lesser extent to the cultivation phase.

Candida ethanolica n. sp.

PubMed

Rybárová, J; Stros, F; Kocková-Kratochvílová, A

1980-01-01

A new yeast, Candida ethanolica, isolated from industrial fodder yeast cultivated on synthetic ethanol as the only source of carbon, originally designated III-5 and III-6, is described. This species differs from all recently accepted Candida species in not assimilating nitrate, not producing urease and not fermenting sugars.

Low pressure steam expansion pretreatment as a competitive approach to improve diosgenin yield and the production of fermentable sugar from Dioscorea zingiberensis C.H. Wright.

PubMed

Wei, Mi; Tong, Yao; Wang, Hongbo; Wang, Lihua; Yu, Longjiang

2016-04-01

Development of efficient pretreatment methods which can disrupt the peripheral lignocellulose and even the parenchyma cells is of great importance for production of diosgenin from turmeric rhizomes. It was found that low pressure steam expansion pretreatment (LSEP) could improve the diosgenin yield by more than 40% compared with the case without pretreatment, while simultaneously increasing the production of fermentable sugar by 27.37%. Furthermore, little inhibitory compounds were produced in LSEP process which was extremely favorable for the subsequent biotransformation of fermentable sugar to other valuable products such as ethanol. Preliminary study showed that the ethanol yield when using the fermentable sugar as carbon source was comparable to that using glucose. The liquid residue of LSEP treated turmeric tuber after diosgenin production can be utilized as a quality fermentable carbon source. Therefore, LSEP has great potential in industrial application in diosgenin clean production and comprehensive utilization of turmeric tuber. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biosynthesis of poly(3-hydroxybutyrate) (PHB) by Cupriavidus necator H16 from jatropha oil as carbon source.

PubMed

Batcha, Abeed Fatima Mohidin; Prasad, D M Reddy; Khan, Maksudur R; Abdullah, Hamidah

2014-05-01

Poly(3-hydroxybutyrate) (PHB) is a biodegradable polymer that can be synthesized through bacterial fermentation. In this study, Cupriavidus necator H16 is used to synthesize PHB by using Jatropha oil as its sole carbon source. Different variables mainly jatropha oil and urea concentrations, and agitation rate were investigated to determine the optimum condition for microbial fermentation in batch culture. Based on the results, the highest cell dry weight and PHB concentrations of 20.1 and 15.5 g/L, respectively, were obtained when 20 g/L of jatropha oil was used. Ethanol was used as external stress factor and the addition of 1.5 % ethanol at 38 h had a positive effect with a high PHB yield of 0.987 g PHB/g jatropha oil. The kinetic studies for cell growth rate and PHB production were conducted and the data were fitted with Logistic and Leudeking–Piret models. The rate constants were evaluated and the theoretical values were in accordance with the experimental data obtained

Heavy metal removal from synthetic wastewaters in an anaerobic bioreactor using stillage from ethanol distilleries as a carbon source.

PubMed

Gonçalves, M M M; da Costa, A C A; Leite, S G F; Sant'Anna, G L

2007-11-01

This work was conducted to investigate the possibility of using stillage from ethanol distilleries as substrate for sulfate reducing bacteria (SRB) growth and to evaluate the removal efficiency of heavy metals present in wastewaters containing sulfates. The experiments were carried out in a continuous bench-scale Upflow Anaerobic Sludge Blanket reactor (13 l) operated with a hydraulic retention time of 18 h. The bioreactor was inoculated with 7 l of anaerobic sludge. Afterwards, an enrichment procedure to increase SRB numbers was started. After this, cadmium and zinc were added to the synthetic wastewater, and their removal as metal sulfide was evaluated. The synthetic wastewater used represented the drainage from a dam of a metallurgical industry to which a carbon source (stillage) was added. The results showed that high percentages of removal (>99%) of Cd and Zn were attained in the bioreactor, and that the removal as sulfide precipitates was not the only form of metal removal occurring in the bioreactor environment.

Physicochemical factors affecting ethanol adsorption by activated carbon.

PubMed

Bradley, K J; Hamdy, M K; Toledo, R T

1987-03-01

Powder and granular activated charcoal were evaluated for ethanol adsorptivity from aqueous mixtures using an adsorption isotherm. Ethanol adsorption capacity was more pronounced at 25 degrees C as compared to 5, 15, and 40 degrees C. When pH of the ethanol-buffer mixture (0.09 ionic strength) was changed from acidic (2.3) to neutral and then to alkaline (11.2), ethanol adsorption was decreased. Increasing ionic strength of the ethanol-buffer mixtures from 0.05 to 0.09 enhanced ethanol adsorption but a further increase to 0.14 showed no significant effect. Ethanol adsorption was more efficient from an aqueous ethanol mixture as compared to semidefined and nondefined fermentation worts, respectively. Heating granular charcoal to 400 degrees C for 1 h and 600 degrees C for 3 h in N(2) increased ethanol adsorptivity and heating to 1000 degrees C (1 h) in CO(2) decreased it when ethanol was removed from dilute solutions by simple pass adsorption in a carbon packed column. Granular charcoal was superior to powdered charcoal and an inverse relationship was noted between the weight of the granular carbon bed in the column and ethanol adsorbed/g carbon. Decreasing the column feed flow rate from 7.5 to 2.0 L aqueous ethanol/min increased the adsorption rate.

The switch from fermentation to respiration in Saccharomyces cerevisiae is regulated by the Ert1 transcriptional activator/repressor.

PubMed

Gasmi, Najla; Jacques, Pierre-Etienne; Klimova, Natalia; Guo, Xiao; Ricciardi, Alessandra; Robert, François; Turcotte, Bernard

2014-10-01

In the yeast Saccharomyces cerevisiae, fermentation is the major pathway for energy production, even under aerobic conditions. However, when glucose becomes scarce, ethanol produced during fermentation is used as a carbon source, requiring a shift to respiration. This adaptation results in massive reprogramming of gene expression. Increased expression of genes for gluconeogenesis and the glyoxylate cycle is observed upon a shift to ethanol and, conversely, expression of some fermentation genes is reduced. The zinc cluster proteins Cat8, Sip4, and Rds2, as well as Adr1, have been shown to mediate this reprogramming of gene expression. In this study, we have characterized the gene YBR239C encoding a putative zinc cluster protein and it was named ERT1 (ethanol regulated transcription factor 1). ChIP-chip analysis showed that Ert1 binds to a limited number of targets in the presence of glucose. The strongest enrichment was observed at the promoter of PCK1 encoding an important gluconeogenic enzyme. With ethanol as the carbon source, enrichment was observed with many additional genes involved in gluconeogenesis and mitochondrial function. Use of lacZ reporters and quantitative RT-PCR analyses demonstrated that Ert1 regulates expression of its target genes in a manner that is highly redundant with other regulators of gluconeogenesis. Interestingly, in the presence of ethanol, Ert1 is a repressor of PDC1 encoding an important enzyme for fermentation. We also show that Ert1 binds directly to the PCK1 and PDC1 promoters. In summary, Ert1 is a novel factor involved in the regulation of gluconeogenesis as well as a key fermentation gene. Copyright © 2014 by the Genetics Society of America.

Carbon Calculator for Land Use Change from Biofuels Production (CCLUB). Users' manual and technical documentation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mueller, S; Dunn, JB; Wang, M

2012-06-07

The Carbon Calculator for Land Use Change from Biofuels Production (CCLUB) calculates carbon emissions from land use change (LUC) for four different ethanol production pathways including corn grain ethanol and cellulosic ethanol from corn stover, miscanthus, and switchgrass. This document discusses the version of CCLUB released May 31, 2012 which includes corn, as did the previous CCLUB version, and three cellulosic feedstocks: corn stover, miscanthus, and switchgrass. CCLUB calculations are based upon two data sets: land change areas and above- and below-ground carbon content. Table 1 identifies where these data are stored and used within the CCLUB model, which ismore » built in MS Excel. Land change area data is from Purdue University's Global Trade Analysis Project (GTAP) model, a computable general equilibrium (CGE) economic model. Section 2 describes the GTAP data CCLUB uses and how these data were modified to reflect shrubland transitions. Feedstock- and spatially-explicit below-ground carbon content data for the United States were generated with a surrogate model for CENTURY's soil organic carbon sub-model (Kwon and Hudson 2010) as described in Section 3. CENTURY is a soil organic matter model developed by Parton et al. (1987). The previous CCLUB version used more coarse domestic carbon emission factors. Above-ground non-soil carbon content data for forest ecosystems was sourced from the USDA/NCIAS Carbon Online Estimator (COLE) as explained in Section 4. We discuss emission factors used for calculation of international greenhouse gas (GHG) emissions in Section 5. Temporal issues associated with modeling LUC emissions are the topic of Section 6. Finally, in Section 7 we provide a step-by-step guide to using CCLUB and obtaining results.« less

Kinetic models for batch ethanol production from sweet sorghum juice under normal and high gravity fermentations: Logistic and modified Gompertz models.

PubMed

Phukoetphim, Niphaphat; Salakkam, Apilak; Laopaiboon, Pattana; Laopaiboon, Lakkana

2017-02-10

The aim of this study was to model batch ethanol production from sweet sorghum juice (SSJ), under normal gravity (NG, 160g/L of total sugar) and high gravity (HG, 240g/L of total sugar) conditions with and without nutrient supplementation (9g/L of yeast extract), by Saccharomyces cerevisiae NP 01. Growth and ethanol production increased with increasing initial sugar concentration, and the addition of yeast extract enhanced both cell growth and ethanol production. From the results, either logistic or a modified Gompertz equation could be used to describe yeast growth, depending on information required. Furthermore, the modified Gompertz model was suitable for modeling ethanol production. Both the models fitted the data very well with coefficients of determination exceeding 0.98. The results clearly showed that these models can be employed in the development of ethanol production processes using SSJ under both NG and HG conditions. The models were also shown to be applicable to other ethanol fermentation systems employing pure and mixed sugars as carbon sources. Copyright © 2016 Elsevier B.V. All rights reserved.

Biofuel cell based on direct bioelectrocatalysis.

PubMed

Ramanavicius, Arunas; Kausaite, Asta; Ramanaviciene, Almira

2005-04-15

A biofuel cell, consisting of two 3mm diameter carbon rod electrodes and operating at ambient temperature in aqueous solution, pH 6, is described. Biofuel cell based on enzymes able to exchange directly electrons with carbon electrodes was constructed and characterized. Anode of the biofuel cell was based on immobilized Quino-hemoprotein alcohol dehydrogenase from Gluconobacter sp. 33 (QH-ADH), cathode on co-immobilized glucose oxidase from Aspergilus niger (GO(x)) and microperoxidase 8 from the horse heart (MP-8) acting in the consecutive mode. Two enzymes GO(x) and MP-8 applied in the design of biofuel cell cathode were acting in consecutive mode and by hydrogen peroxide oxidized MP-8 was directly accepting electrons from carbon rod electrode. If ethanol was applied as an energy source the maximal open circuit potential of the biofuel cell was -125 mV. If glucose was applied as energy source the open circuit potential of the cell was +145 mV. The maximal open circuit potential (270 mV) was achieved in the presence of extent concentration (over 2 mM) of both substrates (ethanol and glucose). Operational half-life period (tau(1/2)) of the biofuel cell was found to be 2.5 days.

Biological nitrate removal processes from drinking water supply-a review.

PubMed

Mohseni-Bandpi, Anoushiravan; Elliott, David Jack; Zazouli, Mohammad Ali

2013-12-19

This paper reviews both heterotrophic and autotrophic processes for the removal of nitrate from water supplies. The most commonly used carbon sources in heterotrophic denitrification are methanol, ethanol and acetic acid. Process performance for each feed stock is compared with particular reference nitrate and nitrite residual and to toxicity potential. Autotrophic nitrate removal has the advantages of not requiring an organic carbon source; however the slow growth rate of autotrophic bacteria and low nitrate removal rate have contributed to the fact that relatively few full scale plants are in operation at the present time.

Biological nitrate removal processes from drinking water supply-a review

PubMed Central

2013-01-01

This paper reviews both heterotrophic and autotrophic processes for the removal of nitrate from water supplies. The most commonly used carbon sources in heterotrophic denitrification are methanol, ethanol and acetic acid. Process performance for each feed stock is compared with particular reference nitrate and nitrite residual and to toxicity potential. Autotrophic nitrate removal has the advantages of not requiring an organic carbon source; however the slow growth rate of autotrophic bacteria and low nitrate removal rate have contributed to the fact that relatively few full scale plants are in operation at the present time. PMID:24355262

Conversion of Carbon Dioxide into Ethanol by Electrochemical Synthesis Method Using Cu-Zn Electrode

NASA Astrophysics Data System (ADS)

Riyanto; Ramadan, S.; Fariduddin, S.; Aminudin, A. R.; Hayatri, A. K.

2018-01-01

Research on conversion of carbon dioxide into ethanol has been done. The conversion process is carried out in a sodium bicarbonate electrolyte solution in an electrochemical synthesis reactor. As cathode was used Cu-Zn, while as anode carbon was utilized. Variations of voltage, concentration of sodium bicarbonate electrolyte solution and time of electrolysis were performed to determine the optimum conditions to convert carbon dioxide into ethanol. Sample of the electrochemical synthesis process was analyzed by gas chromatography. From the result, it is found that the optimum conditions of the electrochemical synthesis process of carbon dioxide conversion into ethanol are voltage, concentration of sodium bicarbonate electrolyte solution and time of electrolysis are 3 volts, 0.4 M and 90 minutes with the ethanol concentration of 10.44%.

Pullulan production by Aureobasidium pullulans grown on ethanol stillage as a nitrogen source.

PubMed

West, T P; Strohfus, B

1996-01-01

Pullulan production by Aureobasidium pullulans strain RP-1 using thin stillage from fuel ethanol production as a nitrogen source was studied in a medium using corn syrup as a carbon source. The use of 1% thin stillage as a nitrogen source instead of ammonium sulphate elevated polysaccharide production by strain RP-1 cells when grown on a concentration of up to 7.5% corn syrup, independent of yeast extract supplementation. Dry weights of cells grown in medium containing ammonium sulphate as the nitrogen source were higher than the stillage-grown cells after 7 days of growth. The viscosity of the polysaccharide on day 7 was higher for cells grown on thin stillage rather than ammonium sulphate as a nitrogen source. The pullulan content of the polysaccharide elaborated by ammonium sulphate-grown cells on day 7 was higher than the pullulan content of polysaccharide produced by stillage-grown cells regardless of whether yeast extract was added to the culture medium.

Carbon Calculator for Land Use Change from Biofuels Production (CCLUB) Users’ Manual and Technical Documentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunn, Jennifer B.; Qin, Zhangcai; Mueller, Steffen

The Carbon Calculator for Land Use Change from Biofuels Production (CCLUB) calculates carbon emissions from land use change (LUC) for four different ethanol production pathways including corn grain ethanol and cellulosic ethanol from corn stover, Miscanthus, and switchgrass, and a soy biodiesel pathway. This document discusses the version of CCLUB released September 30, 2017 which includes five ethanol LUC scenarios and four soy biodiesel LUC scenarios.

Solving ethanol production problems with genetically modified yeast strains.

PubMed

Abreu-Cavalheiro, A; Monteiro, G

2013-01-01

The current world demand for bioethanol is increasing as a consequence of low fossil fuel availability and a growing number of ethanol/gasoline flex-fuel cars. In addition, countries in several parts of the world have agreed to reduce carbon dioxide emissions, and the use of ethanol as a fuel (which produces fewer pollutants than petroleum products) has been considered to be a good alternative to petroleum products. The ethanol that is produced in Brazil from the first-generation process is optimized and can be accomplished at low cost. However, because of the large volume of ethanol that is produced and traded each year, any small improvement in the process could represent a savings of billions dollars. Several Brazilian research programs are investing in sugarcane improvement, but little attention has been given to the improvement of yeast strains that participate in the first-generation process at present. The Brazilian ethanol production process uses sugarcane as a carbon source for the yeast Saccharomyces cerevisiae. Yeast is then grown at a high cellular density and high temperatures in large-capacity open tanks with cells recycle. All of these culture conditions compel the yeast to cope with several types of stress. Among the main stressors are high temperatures and high ethanol concentrations inside the fermentation tanks during alcohol production. Moreover, the competition between the desired yeast strains, which are inoculated at the beginning of the process, with contaminants such as wild type yeasts and bacteria, requires acid treatment to successfully recycle the cells. This review is focused on describing the problems and stressors within the Brazilian ethanol production system. It also highlights some genetic modifications that can help to circumvent these difficulties in yeast.

Solving ethanol production problems with genetically modified yeast strains

PubMed Central

Abreu-Cavalheiro, A.; Monteiro, G.

2013-01-01

The current world demand for bioethanol is increasing as a consequence of low fossil fuel availability and a growing number of ethanol/gasoline flex-fuel cars. In addition, countries in several parts of the world have agreed to reduce carbon dioxide emissions, and the use of ethanol as a fuel (which produces fewer pollutants than petroleum products) has been considered to be a good alternative to petroleum products. The ethanol that is produced in Brazil from the first-generation process is optimized and can be accomplished at low cost. However, because of the large volume of ethanol that is produced and traded each year, any small improvement in the process could represent a savings of billions dollars. Several Brazilian research programs are investing in sugarcane improvement, but little attention has been given to the improvement of yeast strains that participate in the first-generation process at present. The Brazilian ethanol production process uses sugarcane as a carbon source for the yeast Saccharomyces cerevisiae. Yeast is then grown at a high cellular density and high temperatures in large-capacity open tanks with cells recycle. All of these culture conditions compel the yeast to cope with several types of stress. Among the main stressors are high temperatures and high ethanol concentrations inside the fermentation tanks during alcohol production. Moreover, the competition between the desired yeast strains, which are inoculated at the beginning of the process, with contaminants such as wild type yeasts and bacteria, requires acid treatment to successfully recycle the cells. This review is focused on describing the problems and stressors within the Brazilian ethanol production system. It also highlights some genetic modifications that can help to circumvent these difficulties in yeast. PMID:24516432

Formic Acid Formation by Clostridium ljungdahlii at Elevated Pressures of Carbon Dioxide and Hydrogen

PubMed Central

Oswald, Florian; Stoll, I. Katharina; Zwick, Michaela; Herbig, Sophia; Sauer, Jörg; Boukis, Nikolaos; Neumann, Anke

2018-01-01

Low productivities of bioprocesses using gaseous carbon and energy sources are usually caused by the low solubility of those gases (e.g., H2 and CO). It has been suggested that increasing the partial pressure of those gases will result in higher dissolved concentrations and should, therefore, be helpful to overcome this obstacle. Investigations of the late 1980s with mixtures of hydrogen and carbon monoxide showed inhibitory effects of carbon monoxide partial pressures above 0.8 bar. Avoiding any effects of carbon monoxide, we investigate growth and product formation of Clostridium ljungdahlii at absolute process pressures of 1, 4, and 7 bar in batch stirred tank reactor cultivations with carbon dioxide and hydrogen as sole gaseous carbon and energy source. With increasing process pressure, the product spectrum shifts from mainly acetic acid and ethanol to almost only formic acid at a total system pressure of 7 bar. On the other hand, no significant changes in overall product yield can be observed. By keeping the amount of substance flow rate constant instead of the volumetric gas feed rate when increasing the process pressure, we increased the overall product yield of 7.5 times of what has been previously reported in the literature. After 90 h of cultivation at a total pressure of 7 bar a total of 4 g L−1 of products is produced consisting of 82.7 % formic acid, 15.6 % acetic acid, and 1.7 % ethanol. PMID:29484294

Impact of pretreated Switchgrass and biomass carbohydrates on Clostridium thermocellum ATCC 27405 cellulosome composition: a quantitative proteomic analysis.

PubMed

Raman, Babu; Pan, Chongle; Hurst, Gregory B; Rodriguez, Miguel; McKeown, Catherine K; Lankford, Patricia K; Samatova, Nagiza F; Mielenz, Jonathan R

2009-01-01

Economic feasibility and sustainability of lignocellulosic ethanol production requires the development of robust microorganisms that can efficiently degrade and convert plant biomass to ethanol. The anaerobic thermophilic bacterium Clostridium thermocellum is a candidate microorganism as it is capable of hydrolyzing cellulose and fermenting the hydrolysis products to ethanol and other metabolites. C. thermocellum achieves efficient cellulose hydrolysis using multiprotein extracellular enzymatic complexes, termed cellulosomes. In this study, we used quantitative proteomics (multidimensional LC-MS/MS and (15)N-metabolic labeling) to measure relative changes in levels of cellulosomal subunit proteins (per CipA scaffoldin basis) when C. thermocellum ATCC 27405 was grown on a variety of carbon sources [dilute-acid pretreated switchgrass, cellobiose, amorphous cellulose, crystalline cellulose (Avicel) and combinations of crystalline cellulose with pectin or xylan or both]. Cellulosome samples isolated from cultures grown on these carbon sources were compared to (15)N labeled cellulosome samples isolated from crystalline cellulose-grown cultures. In total from all samples, proteomic analysis identified 59 dockerin- and 8 cohesin-module containing components, including 16 previously undetected cellulosomal subunits. Many cellulosomal components showed differential protein abundance in the presence of non-cellulose substrates in the growth medium. Cellulosome samples from amorphous cellulose, cellobiose and pretreated switchgrass-grown cultures displayed the most distinct differences in composition as compared to cellulosome samples from crystalline cellulose-grown cultures. While Glycoside Hydrolase Family 9 enzymes showed increased levels in the presence of crystalline cellulose, and pretreated switchgrass, in particular, GH5 enzymes showed increased levels in response to the presence of cellulose in general, amorphous or crystalline. Overall, the quantitative results suggest a coordinated substrate-specific regulation of cellulosomal subunit composition in C. thermocellum to better suit the organism's needs for growth under different conditions. To date, this study provides the most comprehensive comparison of cellulosomal compositional changes in C. thermocellum in response to different carbon sources. Such studies are vital to engineering a strain that is best suited to grow on specific substrates of interest and provide the building blocks for constructing designer cellulosomes with tailored enzyme composition for industrial ethanol production.

Ternary Pt/Rh/SnO2 electrocatalysts for oxidizing ethanol to CO2.

PubMed

Kowal, A; Li, M; Shao, M; Sasaki, K; Vukmirovic, M B; Zhang, J; Marinkovic, N S; Liu, P; Frenkel, A I; Adzic, R R

2009-04-01

Ethanol, with its high energy density, likely production from renewable sources and ease of storage and transportation, is almost the ideal combustible for fuel cells wherein its chemical energy can be converted directly into electrical energy. However, commercialization of direct ethanol fuel cells has been impeded by ethanol's slow, inefficient oxidation even at the best electrocatalysts. We synthesized a ternary PtRhSnO(2)/C electrocatalyst by depositing platinum and rhodium atoms on carbon-supported tin dioxide nanoparticles that is capable of oxidizing ethanol with high efficiency and holds great promise for resolving the impediments to developing practical direct ethanol fuel cells. This electrocatalyst effectively splits the C-C bond in ethanol at room temperature in acid solutions, facilitating its oxidation at low potentials to CO(2), which has not been achieved with existing catalysts. Our experiments and density functional theory calculations indicate that the electrocatalyst's activity is due to the specific property of each of its constituents, induced by their interactions. These findings help explain the high activity of Pt-Ru for methanol oxidation and the lack of it for ethanol oxidation, and point to the way to accomplishing the C-C bond splitting in other catalytic processes.

High resolution techno-ecological modeling of a bioenergy landscape to identify climate mitigation opportunities in cellulosic ethanol production

USDA-ARS?s Scientific Manuscript database

Meeting current biofuel mandates or creating future carbon-negative biopower systems requires feedstocks be sourced in sufficient quantities at low cost and with minimal environmental impact. Cultivating perennial grasses on low-quality lands is a promising feedstock supply strategy minimizing on-...

Stereochemistry of Furfural Reduction by a Saccharomyces cerevisiae Aldehyde Reductase That Contributes to In Situ Furfural Detoxification

USDA-ARS?s Scientific Manuscript database

Ari1p from Saccharomyces cerevisiae, recently identified as an intermediate subclass short-chain dehydrogenase/reductase, contributes in situ to the detoxification of furfural. Furfural inhibits efficient ethanol production by the yeast, particularly when the carbon source is acid-treated lignocell...

Cellobiose fermenting yeast produces varied forms of native ß-glucosidase

USDA-ARS?s Scientific Manuscript database

The rapid growing yeast strain NRRL Y-50464 is robust to environmental stress and resistant to 2-furaldehyde (furfural) and 5-[hydroxymethyl]-2-furaldehyde (HMF). It is able to utilize cellobiose as its sole source of carbon and produces ethanol from lignocellulosic biomass by simultaneous saccharif...

Integrated Mid-Continent Carbon Capture, Sequestration & Enhanced Oil Recovery Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brian McPherson

2010-08-31

A consortium of research partners led by the Southwest Regional Partnership on Carbon Sequestration and industry partners, including CAP CO2 LLC, Blue Source LLC, Coffeyville Resources, Nitrogen Fertilizers LLC, Ash Grove Cement Company, Kansas Ethanol LLC, Headwaters Clean Carbon Services, Black & Veatch, and Schlumberger Carbon Services, conducted a feasibility study of a large-scale CCS commercialization project that included large-scale CO{sub 2} sources. The overall objective of this project, entitled the 'Integrated Mid-Continent Carbon Capture, Sequestration and Enhanced Oil Recovery Project' was to design an integrated system of US mid-continent industrial CO{sub 2} sources with CO{sub 2} capture, and geologicmore » sequestration in deep saline formations and in oil field reservoirs with concomitant EOR. Findings of this project suggest that deep saline sequestration in the mid-continent region is not feasible without major financial incentives, such as tax credits or otherwise, that do not exist at this time. However, results of the analysis suggest that enhanced oil recovery with carbon sequestration is indeed feasible and practical for specific types of geologic settings in the Midwestern U.S.« less

Xylose fermentation to ethanol by new Galactomyces geotrichum and Candida akabanensis strains.

PubMed

Valinhas, Raquel V; Pantoja, Lílian A; Maia, Ana Carolina F; Miguel, Maria Gabriela C P; Vanzela, Ana Paula F C; Nelson, David L; Santos, Alexandre S

2018-01-01

The conversion of pentoses into ethanol remains a challenge and could increase the supply of second-generation biofuels. This study sought to isolate naturally occurring yeasts from plant biomass and determine their capabilities for transforming xylose into ethanol. Three yeast strains with the ability to ferment xylose were isolated from pepper, tomato and sugarcane bagasse. The strains selected were characterized by morphological and auxanographic assays, and they were identified by homology analysis of 5.8 S and 26 S ribosomal RNA gene sequences. The identities of two lineages of microrganism were associated with Galactomyces geotrichum , and the other was associated with Candida akabanensis . Fermentative processes were conducted with liquid media containing only xylose as the carbon source. Y P/S values for the production of ethanol ranging between 0.29 and 0.35 g g -1 were observed under non-optimized conditions.

Carbon recovery by fermentation of CO-rich off gases - Turning steel mills into biorefineries.

PubMed

Molitor, Bastian; Richter, Hanno; Martin, Michael E; Jensen, Rasmus O; Juminaga, Alex; Mihalcea, Christophe; Angenent, Largus T

2016-09-01

Technological solutions to reduce greenhouse gas (GHG) emissions from anthropogenic sources are required. Heavy industrial processes, such as steel making, contribute considerably to GHG emissions. Fermentation of carbon monoxide (CO)-rich off gases with wild-type acetogenic bacteria can be used to produce ethanol, acetate, and 2,3-butanediol, thereby, reducing the carbon footprint of heavy industries. Here, the processes for the production of ethanol from CO-rich off gases are discussed and a perspective on further routes towards an integrated biorefinery at a steel mill is given. Recent achievements in genetic engineering as well as integration of other biotechnology platforms to increase the product portfolio are summarized. Already, yields have been increased and the portfolio of products broadened. To develop a commercially viable process, however, the extraction from dilute product streams is a critical step and alternatives to distillation are discussed. Finally, another critical step is waste(water) treatment with the possibility to recover resources. Copyright © 2016 Elsevier Ltd. All rights reserved.

Caenorhabditis elegans Battling Starvation Stress: Low Levels of Ethanol Prolong Lifespan in L1 Larvae

PubMed Central

Castro, Paola V.; Khare, Shilpi; Young, Brian D.; Clarke, Steven G.

2012-01-01

The nematode Caenorhabditis elegans arrests development at the first larval stage if food is not present upon hatching. Larvae in this stage provide an excellent model for studying stress responses during development. We found that supplementing starved larvae with ethanol markedly extends their lifespan within this L1 diapause. The effects of ethanol-induced lifespan extension can be observed when the ethanol is added to the medium at any time between 0 and 10 days after hatching. The lowest ethanol concentration that extended lifespan was 1 mM (0.005%); higher concentrations to 68 mM (0.4%) did not result in increased survival. In spite of their extended survival, larvae did not progress to the L2 stage. Supplementing starved cultures with n-propanol and n-butanol also extended lifespan, but methanol and isopropanol had no measurable effect. Mass spectrometry analysis of nematode fatty acids and amino acids revealed that L1 larvae can incorporate atoms from ethanol into both types of molecules. Based on these data, we suggest that ethanol supplementation may extend the lifespan of L1 larvae by either serving as a carbon and energy source and/or by inducing a stress response. PMID:22279556

Indirect land use change and biofuel policy

NASA Astrophysics Data System (ADS)

Kocoloski, Matthew; Griffin, W. Michael; Matthews, H. Scott

2009-09-01

Biofuel debates often focus heavily on carbon emissions, with parties arguing for (or against) biofuels solely on the basis of whether the greenhouse gas emissions of biofuels are less than (or greater than) those of gasoline. Recent studies argue that land use change leads to significant greenhouse gas emissions, making some biofuels more carbon intensive than gasoline. We argue that evaluating the suitability and utility of biofuels or any alternative energy source within the limited framework of plus and minus carbon emissions is too narrow an approach. Biofuels have numerous impacts, and policy makers should seek compromises rather than relying solely on carbon emissions to determine policy. Here, we estimate that cellulosic ethanol, despite having potentially higher life cycle CO2 emissions (including from land use) than gasoline, would still be cost-effective at a CO2 price of 80 per ton or less, well above estimated CO2 mitigation costs for many alternatives. As an example of the broader approach to biofuel policy, we suggest the possibility of using the potential cost reductions of cellulosic ethanol relative to gasoline to balance out additional carbon emissions resulting from indirect land use change as an example of ways in which policies could be used to arrive at workable solutions.

Carbon monoxide bioconversion to butanol-ethanol by Clostridium carboxidivorans: kinetics and toxicity of alcohols.

PubMed

Fernández-Naveira, Ánxela; Abubackar, Haris Nalakath; Veiga, María C; Kennes, Christian

2016-05-01

Butanol production from carbon monoxide-rich waste gases or syngas is an attractive novel alternative to the conventional acetone-butanol-ethanol (ABE) fermentation. Solvent toxicity is a key factor reported in ABE fermentation with carbohydrates as substrates. However, in the gas-fermentation process, kinetic aspects and the inhibition effect of solvents have not thoroughly been studied. Therefore, different batch bottle experiments were carried out with the bacterial species Clostridium carboxidivorans using CO as carbon source for butanol-ethanol fermentation. A maximum specific growth rate of 0.086 ± 0.004 h(-1) and a biomass yield of 0.011 gbiomass/gCO were found, which is significantly lower than in other clostridia grown on sugars. Besides, three assays were carried out to check the inhibitory effect of butanol, ethanol, and their mixtures. Butanol had a higher inhibitory effect on the cells than ethanol and showed a lower IC50, reduced growth rate, and slower CO consumption with increasing alcohol concentrations. A concentration of 14-14.50 g/L butanol caused 50 % growth inhibition in C. carboxidivorans, and 20 g/L butanol resulted in complete inhibition, with a growth rate of 0 h(-1). Conversely, 35 g/L ethanol decreased by 50 % the final biomass concentration respect to the control and yielded the lowest growth rate of 0.024 h(-1). The inhibitory effect of mixtures of both alcohols was also checked adding similar, near identical, concentrations of each one. Growth decreased by 50 % in the presence of a total concentration of alcohols of 16.22 g/L, consisting of similar amounts of each alcohol. Occasional differences in initially added concentrations of alcohols were minimal. The lowest growth rate (0.014 h(-1)) was observed at the highest concentration assayed (25 g/L).

Traffic Related Air Quality Trends in São Paulo, Brazil

NASA Astrophysics Data System (ADS)

Perez-Martinez, P.; Andrade, M. D. F.

2014-12-01

An air quality based approach is used to determine pollutant-trends of carbon monoxide (CO), nitrogen oxides (NOX), ozone (O3) and particle matter (PM10) mostly from road transport sources in the Metropolitan Region of São Paulo (MRSP) for the years 2000-2013. Road transport sources included flex (gasoline and ethanol) cars and motorcycles and diesel trucks and buses. Air pollutant concentrations for the transport sources were measured and related with the fuel sales by the emission factors (EFs) expressed in grams of pollutant per kilometer driven or unit of fuel consumed. Over the 14- year time period, pollutant concentrations of NOX, CO and PM10 decreased by 0.65, 0.37 and 0.71% month-1, respectively. Oppossitely during this time, fuel sales of gasoline, ethanol and diesel increased by 0.26, 1.96 and 0.38% month-1. Flex engines are the prevalent road source of CO, oppositely to diesel ones which appear to be the major source of NOX and PM10. Decrease in air pollutants are partially offset by the increment of fuel sales and related transport activity. For CO, there have been steep decreases in pollutant concentrations (rate of -5 parts per billion, ppb, month-1) for gasoline and ethanol engines between 2000 and 2013. Similarly, diesel related NOX and PM10 concentrations decreased but at slower time rates (-0.25 and -0.09 ppb month-1). Rates uncertainties are larger for diesel pollutants (coefficient of determination R of -0.47 and -0.41) than for gasoline and ethanol related CO (R equal to -0.72). This paper led to the following conclusions: (1) concentrations of gasoline and ethanol related CO, estimated by air quality network measurements, decreased at steeper rate than diesel pollutants NOX and PM10, (2) transport source contributions to the O3 formation differ significantly through the time period focus of this work, with higher contributions coming from gasoline and ethanol engines at the beinning of the reviewed period (2000-2007) and from diesel engines at the end (2008-2013).

Ethanol production efficiency of an anaerobic hemicellulolytic thermophilic bacterium, strain NTOU1, isolated from a marine shallow hydrothermal vent in Taiwan.

PubMed

Tsai, Tsai-Ling; Liu, Shiu-Mei; Lee, Shi-Chiang; Chen, Wei-Jei; Chou, Sheng-Hsin; Hsu, Tseng-Chieh; Guo, Gia-Luen; Hwang, Wen-Song; Wiegel, Juergen

2011-01-01

A new extremely thermophilic, anaerobic, gram-negative bacterium, strain NTOU1, was enriched and isolated from acidic marine hydrothermal fluids off Gueishandao island in Taiwan with 0.5% starch and 0.5% maltose as carbon sources. This strain was capable of growth utilizing various sugars found in lignocellulosic biomass as well as xylan and cellulose, and produced ethanol, lactate, acetate, and CO(2) as fermentation products. The results of a 16S rRNA gene sequence analysis (1,520 bp) revealed NTOU1 to belong to the genus Thermoanaerobacterium. When tested for the ability to grow and produce ethanol from xylose or rice straw hemicellulosic hydrolysate at 70°C, the strain showed the highest levels of ethanol production (1.65 mol ethanol mol xylose(-1)) in a medium containing 0.5% xylose plus 0.5% yeast extract. Maximum ethanol production from the rice straw hemicellulose was 0.509 g g(-1), equivalent to 98.8% theoretical conversion efficiency. Low concentrations of inhibitors (derived from dilute acid hydrolysis) in the rice straw hemicellulose hydrolysate did not affect the ethanol yield. Thus, Thermoanaerobacterium strain NTOU1 has the potential to be used for ethanol production from hemicellulose.

Systems analysis of ethanol production in the genetically engineered cyanobacterium Synechococcus sp. PCC 7002.

PubMed

Kopka, Joachim; Schmidt, Stefanie; Dethloff, Frederik; Pade, Nadin; Berendt, Susanne; Schottkowski, Marco; Martin, Nico; Dühring, Ulf; Kuchmina, Ekaterina; Enke, Heike; Kramer, Dan; Wilde, Annegret; Hagemann, Martin; Friedrich, Alexandra

2017-01-01

Future sustainable energy production can be achieved using mass cultures of photoautotrophic microorganisms, which are engineered to synthesize valuable products directly from CO 2 and sunlight. As cyanobacteria can be cultivated in large scale on non-arable land, these phototrophic bacteria have become attractive organisms for production of biofuels. Synechococcus sp. PCC 7002, one of the cyanobacterial model organisms, provides many attractive properties for biofuel production such as tolerance of seawater and high light intensities. Here, we performed a systems analysis of an engineered ethanol-producing strain of the cyanobacterium Synechococcus sp. PCC 7002, which was grown in artificial seawater medium over 30 days applying a 12:12 h day-night cycle. Biosynthesis of ethanol resulted in a final accumulation of 0.25% (v/v) ethanol, including ethanol lost due to evaporation. The cultivation experiment revealed three production phases. The highest production rate was observed in the initial phase when cells were actively growing. In phase II growth of the producer strain stopped, but ethanol production rate was still high. Phase III was characterized by a decrease of both ethanol production and optical density of the culture. Metabolomics revealed that the carbon drain due to ethanol diffusion from the cell resulted in the expected reduction of pyruvate-based intermediates. Carbon-saving strategies successfully compensated the decrease of central intermediates of carbon metabolism during the first phase of fermentation. However, during long-term ethanol production the producer strain showed clear indications of intracellular carbon limitation. Despite the decreased levels of glycolytic and tricarboxylic acid cycle intermediates, soluble sugars and even glycogen accumulated in the producer strain. The changes in carbon assimilation patterns are partly supported by proteome analysis, which detected decreased levels of many enzymes and also revealed the stress phenotype of ethanol-producing cells. Strategies towards improved ethanol production are discussed. Systems analysis of ethanol production in Synechococcus sp. PCC 7002 revealed initial compensation followed by increasing metabolic limitation due to excessive carbon drain from primary metabolism.

Carbon Calculator for Land Use Change from Biofuels Production (CCLUB). Users' Manual and Technical Documentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunn, Jennifer B.; Qin, Zhangcai; Mueller, Steffen

The Carbon Calculator for Land Use Change from Biofuels Production (CCLUB) calculates carbon emissions from land use change (LUC) for four different ethanol production pathways including corn grain ethanol and cellulosic ethanol from corn stover, Miscanthus, and switchgrass. This document discusses the version of CCLUB released September 30, 2014 which includes corn and three cellulosic feedstocks: corn stover, Miscanthus, and switchgrass.

Tracing the role of endogenous carbon in denitrification using wine industry by-product as an external electron donor: Coupling isotopic tools with mathematical modeling.

PubMed

Carrey, R; Rodríguez-Escales, P; Soler, A; Otero, N

2018-02-01

Nitrate removal through enhanced biological denitrification (EBD), consisting of the inoculation of an external electron donor, is a feasible solution for the recovery of groundwater quality. In this context, liquid waste from wine industries (wine industry by-products, WIB) may be feasible for use as a reactant to enhance heterotrophic denitrification. To address the feasibility of WIB as electron donor to promote denitrification, as well as to evaluate the role of biomass as a secondary organic C source, a flow-through experiment was carried out. Chemical and isotopic characterization was performed and coupled with mathematical modeling. Complete nitrate attenuation with no nitrite accumulation was successfully achieved after 10 days. Four different C/N molar ratios (7.0, 2.0, 1.0 and 0) were tested. Progressive decrease of the C/N ratio reduced the remaining C in the outflow and favored biomass migration, producing significant changes in dispersivity in the reactor, which favored efficient nitrate degradation. The applied mathematical model described the general trends for nitrate, ethanol, dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) concentrations. This model shows how the biomass present in the system is degraded to dissolved organic C (DOC en ) and becomes the main source of DOC for a C/N ratio between 1.0 and 0. The isotopic model developed for organic and inorganic carbon also describes the general trends of δ 13 C of ethanol, DOC and DIC in the outflow water. The study of the evolution of the isotopic fractionation of organic C using a Rayleigh distillation model shows the shift in the organic carbon source from the WIB to the biomass and is in agreement with the isotopic fractionation values used to calibrate the model. Isotopic fractionations (ε) of C-ethanol and C-DOC en were -1‰ and -5‰ (model) and -3.3‰ and -4.8‰ (Rayleigh), respectively. In addition, an inverse isotopic fractionation of +10‰ was observed for biomass degradation to DOC en . Overall, WIB can efficiently promote nitrate reduction in EBD treatments. The conceptual model of the organic C cycle and the developed mathematical model accurately described the chemical and isotopic transformations that occur during this induced denitrification. Copyright © 2017 Elsevier Ltd. All rights reserved.

Methane emissions and contaminant degradation rates at sites affected by accidental releases of denatured fuel-grade ethanol

NASA Astrophysics Data System (ADS)

Sihota, Natasha J.; Mayer, K. Ulrich; Toso, Mark A.; Atwater, Joel F.

2013-08-01

The recent increase in the use of denatured fuel-grade ethanol (DFE) has enhanced the probability of its environmental release. Due to the highly labile nature of ethanol (EtOH), it is expected to rapidly biodegrade, increasing the potential for inducing methanogenic conditions in the subsurface. As environmental releases of DFE can be expected to occur at the ground surface or in the vadose zone (e.g., due to surficial spills from rail lines or tanker trucks and leaking underground storage tanks), the potential for methane (CH4) generation at DFE spill sites requires evaluation. An assessment is needed because high CH4 generation rates may lead to CH4 fluxes towards the ground surface, which is of particular concern if spills are located close to human habitation—related to concerns of soil vapor intrusion (SVI). This work demonstrates, for the first time, the measurement of surficial gas release rates at large volume DFE spill sites. Two study sites, near Cambria and Balaton, in MN are investigated. Total carbon emissions at the ground surface (summing carbon dioxide (CO2) and CH4 emissions) are used to quantify depth-integrated DFE degradation rates. Results from both sites demonstrate that substantial CO2 and CH4 emissions do occur—even years after a spill. However, large total carbon fluxes, and CH4 emissions in particular, were restricted to a localized area within the DFE source zone. At the Balaton site, estimates of total DFE carbon losses in the source zone ranged between 5 and 174 μmol m- 2 s- 1, and CH4 effluxes ranged between non-detect and 9 μmol m- 2 s- 1. At the Cambria site estimates of total DFE carbon losses in the source zone ranged between 8 and 500 μmol m- 2 s- 1, and CH4 effluxes ranged between non-detect and 393 μmol m- 2 s- 1. Substantial CH4 accumulation, coupled with oxygen (O2) depletion, measured in samples collected from custom-designed gas collection chambers at the Cambria site suggests that the development of explosion or asphyxiation hazards is possible in confined spaces above a rapidly degrading DFE release. However, the results also indicate that the development of such hazards is locally constrained, will require a high degree of soil moisture, close proximity to the source zone, a good connection between the soil and the confined space, and poorly aerated conditions.

Methane emissions and contaminant degradation rates at sites affected by accidental releases of denatured fuel-grade ethanol.

PubMed

Sihota, Natasha J; Mayer, K Ulrich; Toso, Mark A; Atwater, Joel F

2013-08-01

The recent increase in the use of denatured fuel-grade ethanol (DFE) has enhanced the probability of its environmental release. Due to the highly labile nature of ethanol (EtOH), it is expected to rapidly biodegrade, increasing the potential for inducing methanogenic conditions in the subsurface. As environmental releases of DFE can be expected to occur at the ground surface or in the vadose zone (e.g., due to surficial spills from rail lines or tanker trucks and leaking underground storage tanks), the potential for methane (CH4) generation at DFE spill sites requires evaluation. An assessment is needed because high CH4 generation rates may lead to CH4 fluxes towards the ground surface, which is of particular concern if spills are located close to human habitation-related to concerns of soil vapor intrusion (SVI). This work demonstrates, for the first time, the measurement of surficial gas release rates at large volume DFE spill sites. Two study sites, near Cambria and Balaton, in MN are investigated. Total carbon emissions at the ground surface (summing carbon dioxide (CO2) and CH4 emissions) are used to quantify depth-integrated DFE degradation rates. Results from both sites demonstrate that substantial CO2 and CH4 emissions do occur-even years after a spill. However, large total carbon fluxes, and CH4 emissions in particular, were restricted to a localized area within the DFE source zone. At the Balaton site, estimates of total DFE carbon losses in the source zone ranged between 5 and 174 μmol m(-2) s(-1), and CH4 effluxes ranged between non-detect and 9 μmol m(-2) s(-1). At the Cambria site estimates of total DFE carbon losses in the source zone ranged between 8 and 500 μmol m(-2) s(-1), and CH4 effluxes ranged between non-detect and 393 μmol m(-2) s(-1). Substantial CH4 accumulation, coupled with oxygen (O2) depletion, measured in samples collected from custom-designed gas collection chambers at the Cambria site suggests that the development of explosion or asphyxiation hazards is possible in confined spaces above a rapidly degrading DFE release. However, the results also indicate that the development of such hazards is locally constrained, will require a high degree of soil moisture, close proximity to the source zone, a good connection between the soil and the confined space, and poorly aerated conditions. Copyright © 2013 Elsevier B.V. All rights reserved.

The flexible feedstock concept in Industrial Biotechnology: Metabolic engineering of Escherichia coli, Corynebacterium glutamicum, Pseudomonas, Bacillus and yeast strains for access to alternative carbon sources.

PubMed

Wendisch, Volker F; Brito, Luciana Fernandes; Gil Lopez, Marina; Hennig, Guido; Pfeifenschneider, Johannes; Sgobba, Elvira; Veldmann, Kareen H

2016-09-20

Most biotechnological processes are based on glucose that is either present in molasses or generated from starch by enzymatic hydrolysis. At the very high, million-ton scale production volumes, for instance for fermentative production of the biofuel ethanol or of commodity chemicals such as organic acids and amino acids, competing uses of carbon sources e.g. in human and animal nutrition have to be taken into account. Thus, the biotechnological production hosts E. coli, C. glutamicum, pseudomonads, bacilli and Baker's yeast used in these large scale processes have been engineered for efficient utilization of alternative carbon sources. This flexible feedstock concept is central to the use of non-glucose second and third generation feedstocks in the emerging bioeconomy. The metabolic engineering efforts to broaden the substrate scope of E. coli, C. glutamicum, pseudomonads, B. subtilis and yeasts to include non-native carbon sources will be reviewed. Strategies to enable simultaneous consumption of mixtures of native and non-native carbon sources present in biomass hydrolysates will be summarized and a perspective on how to further increase feedstock flexibility for the realization of biorefinery processes will be given. Copyright © 2016 Elsevier B.V. All rights reserved.

The Effects of Voltage and Concentration of Sodium Bicarbonate on Electrochemical Synthesis of Ethanol from Carbon Dioxide Using Brass as Cathode

NASA Astrophysics Data System (ADS)

Ramadan, Septian; Fariduddin, Sholah; Rizki Aminudin, Afianti; Kurnia Hayatri, Antisa; Riyanto

2017-11-01

The effects of voltage and concentration of sodium bicarbonate were investigated to determine the optimum conditions of the electrochemical synthesis process to convert carbon dioxide into ethanol. The conversion process is carried out using a sodium bicarbonate electrolyte solution in an electrochemical synthesis reactor equipped with a cathode and anode. As the cathode was used brass, while as the anode carbon was utilized. Sample of the electrochemical synthesis process was analyzed by gas chromatography to determine the content of the compounds produced. The optimum electrochemical synthesis conditions to convert carbon dioxide into ethanol are voltage and concentration of sodium bicarbonate are 3 volts and 0.4 M with ethanol concentration of 1.33%.

Indole-based assay to assess the effect of ethanol on Pseudomonas putida F1 dioxygenase activity.

PubMed

da Silva, Márcio Luis Busi; Alvarez, Pedro J J

2010-06-01

Toluene dioxygenase (TDO) is ubiquitous in nature and has a broad substrate range, including benzene, toluene, ethylbenzene and xylenes (BTEX). Pseudomonas putida F1 (PpF1) induced on toluene is known to produce indigo from indole through the activity of TDO. In this work, a spectrophotometric assay previously developed to measure indole to indigo production rates was modified to characterize the effects of various ethanol concentrations on toluene aerobic biodegradation activity and assess catabolite repression of TDO. Indigo production rate by cells induced on toluene alone was 0.0012 +/- 0.0006 OD(610) min(-1). The presence of ethanol did not fully repress TDO activity when toluene was also available as a carbon source. However, indigo production rates by PpF1 grown on ethanol:toluene mixtures (3:1 w/w) decreased by approximately 50%. Overall, the proposed spectrophotometric assay is a simple approach to quantify TDO activity, and demonstrates how the presence of ethanol in groundwater contaminated with reformulated gasoline is likely to interfere with naturally occurring microorganisms from fully expressing their aerobic catabolic potential towards hydrocarbons bioremediation.

Isolation and characterization of two novel ethanol-tolerant facultative-anaerobic thermophilic bacteria strains from waste compost.

PubMed

Fong, Jiunn C N; Svenson, Charles J; Nakasugi, Kenlee; Leong, Caine T C; Bowman, John P; Chen, Betty; Glenn, Dianne R; Neilan, Brett A; Rogers, Peter L

2006-10-01

In a search for potential ethanologens, waste compost was screened for ethanol-tolerant thermophilic microorganisms. Two thermophilic bacterial strains, M5EXG and M10EXG, with tolerance of 5 and 10% (v/v) ethanol, respectively, were isolated. Both isolates are facultative anaerobic, non-spore forming, non-motile, catalase-positive, oxidase-negative, Gram-negative rods that are capable of utilizing a range of carbon sources including arabinose, galactose, mannose, glucose and xylose and produce low amounts of ethanol, acetate and lactate. Growth of both isolates was observed in fully defined minimal media within the temperature range 50-80 degrees C and pH 6.0-8.0. Phylogenetic analysis of the 16S rDNA sequences revealed that both isolates clustered with members of subgroup 5 of the genus Bacillus. G+C contents and DNA-DNA relatedness of M5EXG and M10EXG revealed that they are strains belonging to Geobacillus thermoglucosidasius. However, physiological and biochemical differences were evident when isolates M5EXG and M10EXG were compared with G. thermoglucosidasius type strain (DSM 2542(T)). The new thermophilic, ethanol-tolerant strains of G. thermoglucosidasius may be candidates for ethanol production at elevated temperatures.

Equilibrium chemical vapor deposition growth of Bernal-stacked bilayer graphene.

PubMed

Zhao, Pei; Kim, Sungjin; Chen, Xiao; Einarsson, Erik; Wang, Miao; Song, Yenan; Wang, Hongtao; Chiashi, Shohei; Xiang, Rong; Maruyama, Shigeo

2014-11-25

Using ethanol as the carbon source, self-limiting growth of AB-stacked bilayer graphene (BLG) has been achieved on Cu via an equilibrium chemical vapor deposition (CVD) process. We found that during this alcohol catalytic CVD (ACCVD) a source-gas pressure range exists to break the self-limitation of monolayer graphene on Cu, and at a certain equilibrium state it prefers to form uniform BLG with a high surface coverage of ∼94% and AB-stacking ratio of nearly 100%. More importantly, once the BLG is completed, this growth shows a self-limiting manner, and an extended ethanol flow time does not result in additional layers. We investigate the mechanism of this equilibrium BLG growth using isotopically labeled (13)C-ethanol and selective surface aryl functionalization, and results reveal that during the equilibrium ACCVD process a continuous substitution of graphene flakes occurs to the as-formed graphene and the BLG growth follows a layer-by-layer epitaxy mechanism. These phenomena are significantly in contrast to those observed for previously reported BLG growth using methane as precursor.

Metabolism of spacecraft cleaning reagents by Mars Odyssey and Phoenix-associated Acinetobacter

NASA Astrophysics Data System (ADS)

Mogul, Rakesh; Barding, Gregory; Baki, Ryan; Perkins, Nicole; Lee, Sooji; Lalla, Sid; Campos, Alexa; Sripong, Kimberly; Madrid, Steve

2016-07-01

The metabolomic and proteomic properties that promote microbial survival in spacecraft assembly facilities are important aspects to planetary protection and astrobiology. In this presentation, we will provide molecular and biological evidence that the spacecraft-associated Acinetobacter metabolize/degrade spacecraft cleaning reagents such as ethanol, 2-propanol, and Kleenol-30. Gas chromatography-mass spectrometry (GC-MS) studies on A. radioresistens 50v1 (Mars Odyssey) show that the metabolome is dependent upon growth conditions and that ^{13}C-labeled ethanol is incorporated into metabolites such as TCA/glyoxylate cycle intermediates, amino acids, monosaccharides, and disaccharides (e.g., trehalose). In fact, plate count assays show that ethanol is a sole carbon source under minimal conditions for several Mars Phoenix and Odyssey-associated Acinetobacter strains, which may explain why the Acinetobacter are among the most abundant genera found in spacecraft assembly facilities. Biochemical analyses support the enzymatic oxidation of ethanol and 2-propanol by a membrane-bound and NAD+/PQQ-dependent alcohol dehydrogenase, with current kinetic data providing similar apparent K _{M} and maximum growth rate values of ˜5 and 8 mM ethanol, respectively. Preliminary GC-MS analysis also suggests that Kleenol-30 is degraded by A. radioresistens 50v1 when grown in ethanol mixtures. Under minimal conditions, A. radioresistens 50v1 (˜10 ^{8} cfu/mL) also displays a remarkable oxidative extremotolerance (˜2-log reduction in 10 mM hydrogen peroxide), which suggests crucial roles for metabolites associated with oxidative stress (e.g., trehalose) and the observed appreciable catalase specific activities. In conclusion, these results provide key insights into the survival strategies of spacecraft-associated Acinetobacter and emphasize the importance of characterizing the carbon metabolism of forward contaminants.

The contribution of vehicular emission to the atmospheric concentrations of carbon compounds in the Metropolitan Area of Sao Paulo

NASA Astrophysics Data System (ADS)

Andrade, M.; Fornaro, A.; Miranda, R.; Ynoue, R. Y.; Freitas, E. D.; LAPAt-Laboratorio de Analise dos Processos Atmosfericos

2013-05-01

It is recognized that megacities have regional and global effects on climate, and that aerosols and Green House Gases (GHG) constitute the principal tracer of those effects. Such is the case in the Metropolitan Area of Sao Paulo (MASP), one of the largest mega-cities in the world. MASP has a population of almost 20 million inhabitants. The main source of air pollution is the transport sector. In this region, there are approximately 6.5 million passenger cars and commercial vehicles: 85% light duty, 3% heavy-duty diesel vehicles (diesel + 3% bio-diesel) and 12% motorcycles. Of the light duty vehicle, approximately 55% burn a mixture (v/v) of 78% gasoline with 22% ethanol (referred to as gasohol), 4% use hydrated ethanol (95% ethanol + 5% water), 38% flexible fuel vehicles capable of burning both gasohol as hydrated ethanol, and 2% use diesel. In average 50% of the fuel used in MASP is ethanol what brings the necessity of more studies to understand the formation of photochemical oxidants and secondary particles. According to the São Paulo State Environmental Protection Agency, 97% of carbon monoxide (CO), 85% of hydrocarbons (HC), 82% of nitrogen oxides (NOx), 36% of sulfur dioxide emitted, and 36% of all inhalable particulate matter (PM10) are emitted by the vehicular fleet. Concerning particles, 75% of the Fine Particle Concentration is related to the burning of fuel, mainly diesel. The fine particles are composed of Organic Carbon (40%), Black Carbon (30%), ions (15%) and metals. It is known that the soot is warming the climate and is important to the radiative balance. Another important driver to the radiative balance, the CO2 is mainly emitted by the transport sector, which is responsible for 57% of its emission. A comprehensive project under development has the objective of determine the role of MASP as the source of gaseous and particle compounds to the atmosphere of the region and in a mesoscale perspective. The project with funding from the São Paulo Science Foundation, called NARROWING THE UNCERTAINTIES ON AEROSOL AND CLIMATE CHANGES IN SÃO PAULO STATE - NUANCE-SPS, comprising various subprojects, employ measurements and modeling to study gaseous and particles in the atmosphere: sources; evolution in the atmosphere; formation of secondary particles; deposition; and potential impact on the climate and human health. Ground-based and vertical profile measurements are being performed (in situ, ozonesondes and LIDAR). Emission inventory is being elaborated based on the measurements of emission factors from the vehicular fleet. The formation of ozone and fine particles is being modeled with the WRF-Chem (weather and research forecast with chemistry) model. The influence of the megacity emission to the concentration of the secondary pollutants is being evaluated and correlated to health impacts.

Genetic modifications and introduction of heterologous pdc genes in Enterococcus faecalis for its use in production of bioethanol.

PubMed

Rana, N F; Gente, S; Rincé, A; Auffray, Y; Laplace, J M

2012-09-01

Genetically-modified Enterococcus faecalis has a potential of survival and can be used in ethanolic fermentations. Fermentation profiles of E. faecalis JH2-2 were assessed using glucose and lactose as carbon sources. Deletion of lactate dehydrogenase (ldh) genes increased the ethanol production from 0.25 to 0.82 g/l, which was further increased to 0.96 g/l by the insertion of a pyruvate decarboxylase (pdc) gene (from Sarcina ventriculi or Clostridium acetobutylicum) in place ldh1. When grown on lactose, the pdcSv and pdcCa showed 13.6 and 17.6 U mg(-1) of pdc specific activity, respectively. Highest activity (47 U mg(-1)) and ethanol concentration (2.3 g/l) were obtained with pdcCa using an expression plasmid. Formate and acetate were also produced in high quantities. Transcriptional analysis showed that aldehyde alcohol dehydrogenase gene was upregulated up to 16-fold. Further optimizations are required for higher ethanol production.

Ethanol prefermentation of food waste in sequencing batch methane fermentation for improved buffering capacity and microbial community analysis.

PubMed

Yu, Miao; Wu, Chuanfu; Wang, Qunhui; Sun, Xiaohong; Ren, Yuanyuan; Li, Yu-You

2018-01-01

This study investigates the effects of ethanol prefermentation (EP) on methane fermentation. Yeast was added to the substrate for EP in the sequencing batch methane fermentation of food waste. An Illumina MiSeq high-throughput sequencing system was used to analyze changes in the microbial community. Methane production in the EP group (254mL/g VS) was higher than in the control group (35mL/g VS) because EP not only increased the buffering capacity of the system, but also increased hydrolytic acidification. More carbon source was converted to ethanol in the EP group than in the control group, and neutral ethanol could be converted continuously to acetic acid, which promoted the growth of Methanobacterium and Methanosarcina. As a result, the relative abundance of methane-producing bacteria was significantly higher than that of the control group. Kinetic modeling indicated that the EP group had a higher hydrolysis efficiency and shorter lag phase. Copyright © 2017 Elsevier Ltd. All rights reserved.

Energy Potential and Greenhouse Gas Emissions from Bioenergy Cropping Systems on Marginally Productive Cropland

PubMed Central

Schmer, Marty R.; Vogel, Kenneth P.; Varvel, Gary E.; Follett, Ronald F.; Mitchell, Robert B.; Jin, Virginia L.

2014-01-01

Low-carbon biofuel sources are being developed and evaluated in the United States and Europe to partially offset petroleum transport fuels. Current and potential biofuel production systems were evaluated from a long-term continuous no-tillage corn (Zea mays L.) and switchgrass (Panicum virgatum L.) field trial under differing harvest strategies and nitrogen (N) fertilizer intensities to determine overall environmental sustainability. Corn and switchgrass grown for bioenergy resulted in near-term net greenhouse gas (GHG) reductions of −29 to −396 grams of CO2 equivalent emissions per megajoule of ethanol per year as a result of direct soil carbon sequestration and from the adoption of integrated biofuel conversion pathways. Management practices in switchgrass and corn resulted in large variation in petroleum offset potential. Switchgrass, using best management practices produced 3919±117 liters of ethanol per hectare and had 74±2.2 gigajoules of petroleum offsets per hectare which was similar to intensified corn systems (grain and 50% residue harvest under optimal N rates). Co-locating and integrating cellulosic biorefineries with existing dry mill corn grain ethanol facilities improved net energy yields (GJ ha−1) of corn grain ethanol by >70%. A multi-feedstock, landscape approach coupled with an integrated biorefinery would be a viable option to meet growing renewable transportation fuel demands while improving the energy efficiency of first generation biofuels. PMID:24594783

Method and system for ethanol production

DOEpatents

Feder, H.M.; Chen, M.J.

1980-05-21

A transition metal carbonyl and a tertiary amine are employed as a homogeneous catalytic system in methanol or a less volatile solvent to react methanol with carbon monoxide and hydrogen gas producing ethanol and carbon dioxide. The gas contains a high carbon monoxide to hydrogen ratio as is present in a typical gasifier product. The reaction has potential for anhydrous ethanol production as carbon dioxide rather than water is produced. The only other significant by-product is methane. Selected transition metal carbonyls include those of iron, ruthenium and possibly manganese and osmium. Selected amines include trimethylamine, N-Methylpyrrolidine, 24-diazabicyclooctane, dimethyneopentylamine and 2-pryidinol.

Method and system for ethanol production

DOEpatents

Feder, Harold M.; Chen, Michael J.

1981-01-01

A transition metal carbonyl and a tertiary amine are employed as a homogeneous catalytic system in methanol or a less volatile solvent to react methanol with carbon monoxide and hydrogen gas producing ethanol and carbon dioxide. The gas contains a high carbon monoxide to hydrogen ratio as is present in a typical gasifier product. The reaction has potential for anhydrous ethanol production as carbon dioxide rather than water is produced. The only other significant by product is methane. Selected transition metal carbonyls include those of iron, ruthenium and possibly manganese and osmium. Selected amines include trimethylamine, N-Methylpyrrolidine, 24-diazabicyclooctane, dimethyneopentylamine and 2-pryidinol.

Method and system for ethanol production

DOEpatents

Feder, Harold M.; Chen, Michael J.

1983-01-01

A transition metal carbonyl and a tertiary amine are employed as a homogeneous catalytic system in methanol or a less volatile solvent to react methanol with carbon monoxide and hydrogen gas producing ethanol and carbon dioxide. The gas contains a high carbon monoxide to hydrogen ratio as is present in a typical gasifier product. The reaction has potential for anhydrous ethanol production as carbon dioxide rather than water is produced. Selected transition metal carbonyls include those of iron, rhodium ruthenium, manganese in combination with iron and possibly osmium. Selected amines include trimethylamine, N-Methylpyrrolidine, 2,4-diazabicyclooctane, dimethylneopentylamine, N-methylpiperidine and derivatives of N-methylpiperidine.

Method and system for ethanol production

DOEpatents

Feder, H.M.; Chen, M.J.

1981-09-24

A transition metal carbonyl and a tertiary amine are employed as a homogeneous catalytic system in methanol or a less volatile solvent to react methanol with carbon monoxide and hydrogen gas producing ethanol and carbon dioxide. The gas contains a high carbon monoxide to hydrogen ratio as is present in a typical gasifier product. The reaction has potential for anhydrous ethanol production as carbon dioxide rather than water is produced. Selected transition metal carbonyls include those of iron, rhodium, ruthenium, manganese in combination with iron and possibly osmium. Selected amines include trimethylamine, N-Methylpyrrolidine, 2,4-diazabicyclooctane, dimethylneopentylamine, N-methylpiperidine and derivatives of N-methylpiperidine.

OZONE REACTION WITH N-ALDEHYDES (N=4-10), BENZALDEHYDE, ETHANOL, ISOPROPANOL, AND N-PROPANOL ADSORBED ON A DUAL-BED GRAPHITIZED CARBON/CARBON MOLECULAR SIEVE ADSORBENT CARTRIDGE

EPA Science Inventory

Ozone reacts with n-aldehydes (n = 4 - 10), benzaldehyde, ethanol, isopropanol, and n-propanol adsorbed on a dual-bed graphitized carbon/carbon molecular sieve adsorbent cartridge. Destruction of n-aldehydes increases with n number and with ozone concentration. In some samp...

An assessment of potential CO2 Sources throughout the Illinois Basin Subtask 5.1 – CO2 Source Assessment Topical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patel, Vinodkumar; O?Brien, Kevin; Korose, Christopher

Large-scale anthropogenic CO2 sources (>100,000 tonnes/year) were catalogued and assessed for the Illinois East Sub-Basin project area. The portfolio of sources is quite diverse, and contains not only fossil-based power generation facilities but also ethanol, chemical, and refinery facilities. Over 60% of the facilities are relatively new (i.e. post year 2000 construction) hence increasing the likelihood that retrofitting the facility with a carbon capture plant is feasible. Two of the facilities have indicated interest in being “early adopters” should the CarbonSAFE project eventually transition to a build and operate phase: the Prairie State Generating Company’s electricity generation facility near Marissa,more » Illinois, and Quasar Syngas, LLC’s Wabash ammonia/direct-reduced iron plant, currently in development north of Terre Haute, Indiana.« less

Protective effect of ethanolic extract of polyherbal formulation on carbon tetrachloride induced liver injury

PubMed Central

Gurusamy, K; Kokilavani, R; Arumugasamy, K; Sowmia, C

2009-01-01

Protective effect of ethanolic extract of polyherbalformulation (PHF) of three medicinalplants was studied on carbon tetrachloride induced liver damage in rats. Treatment with 250mg I kg b.w. of ethanolic extract of PHF protected rats against carbon tetrachloride liver injury by significantly lowering 5’NT, GGF, GDH and SDH and bilirubin levels compared to control group of rats. Normalising the effect of these parameters indicates strong hepatoprotective property of the PHF extract. PMID:22557313

Selection criteria and performance of energycane clones (Saccharum spp. x S. spontaneum) for biomass production under tropical and sub-tropical conditions

USDA-ARS?s Scientific Manuscript database

The urgent need to reduce our reliance on oil and at the same time reduce carbon emissions, has triggered the search for alternative energy sources such as biofuels. New technologies have made possible the conversion of cellulose and hemicellulose into sugars that can be fermented to produce ethanol...

Implications of Using Corn Stalks as a Biofuel Source: A Joint ARS and DOE Project

NASA Astrophysics Data System (ADS)

Wilhelm, W. W.; Cushman, J.

2003-12-01

Corn stover is a readily source of biomass for cellulosic ethanol production, and may provide additional income for growers. Published research shows that residue removal changes the rate of soil physical, chemical, and biological processes, and in turn, crop growth. Building a sustainable cellulosic ethanol industry based on corn residue requires residue management practices that do not reduce long-term productivity. To develop such systems, impacts of stover removal on the soil and subsequent crops must be quantified. The ARS/DOE Biofuel Project is the cooperative endeavor among scientists from six western Corn Belt US Dept. of Agriculture, Agricultural Research Service (ARS) locations and US Dept. of Energy. The objectives of the project are to determine the influence of stover removal on crop productivity, soil aggregation, quality, carbon content, and seasonal energy balance, and carbon sequestration. When residue is removed soil temperatures fluctuate more and soil water evaporation is greater. Residue removal reduces the amount of soil organic carbon (SOC), but the degree of reduction is highly dependent on degree of tillage, quantity of stover removed, and frequency of stover removal. Of the three cultural factors (stover removal, tillage, and N fertilization) tillage had the greatest effect on amount of corn-derived SOC. No tillage tends to increase the fraction of aggregates in the 2.00 to 0.25 mm size range at all removal rates. Stover harvest reduces corn-derived SOC by 35% compared to retaining stover on the soil averaged over all tillage systems. Corn stover yield has not differed across stover removal treatments in these studies. In the irrigated study, grain yield increased with stover removal. In the rain-fed studies, grain yield has not differed among residue management treatments. Incorporating the biomass ethanol fermentation by-product into a soil with low SOC showed a positive relationship between the amount of lignin added and the subsequent humic acid concentration and aggregate stability. These and future outcomes from this effort will provide DOE and the developing biomass ethanol industry knowledge and guidelines on the environmental and crop productivity consequences of large-scale collection of corn stover.

Xylose Isomerase Improves Growth and Ethanol Production Rates from Biomass Sugars for Both Saccharomyces Pastorianus and Saccharomyces Cerevisiae

PubMed Central

Miller, Kristen P.; Gowtham, Yogender Kumar; Henson, J. Michael; Harcum, Sarah W.

2013-01-01

The demand for biofuel ethanol made from clean, renewable nonfood sources is growing. Cellulosic biomass, such as switch grass (Panicum virgatum L.), is an alternative feedstock for ethanol production; however, cellulosic feedstock hydrolysates contain high levels of xylose, which needs to be converted to ethanol to meet economic feasibility. In this study, the effects of xylose isomerase on cell growth and ethanol production from biomass sugars representative of switch grass were investigated using low cell density cultures. The lager yeast species Saccharomyces pastorianus was grown with immobilized xylose isomerase in the fermentation step to determine the impact of the glucose and xylose concentrations on the ethanol production rates. Ethanol production rates were improved due to xylose isomerase; however, the positive effect was not due solely to the conversion of xylose to xylulose. Xylose isomerase also has glucose isomerase activity, so to better understand the impact of the xylose isomerase on S. pastorianus, growth and ethanol production were examined in cultures provided fructose as the sole carbon. It was observed that growth and ethanol production rates were higher for the fructose cultures with xylose isomerase even in the absence of xylose. To determine whether the positive effects of xylose isomerase extended to other yeast species, a side-by-side comparison of S. pastorianus and Saccharomyces cerevisiae was conducted. These comparisons demonstrated that the xylose isomerase increased ethanol productivity for both the yeast species by increasing the glucose consumption rate. These results suggest that xylose isomerase can contribute to improved ethanol productivity, even without significant xylose conversion. PMID:22866331

Ethanol production method and system

DOEpatents

Chen, M.J.; Rathke, J.W.

1983-05-26

Ethanol is selectively produced from the reaction of methanol with carbon monoxide and hydrogen in the presence of a transition metal carbonyl catalyst. Methanol serves as a solvent and may be accompanied by a less volatile co-solvent. The solution includes the transition metal carbonyl catalysts and a basic metal salt such as an alkali metal or alkaline earth metal formate, carbonate or bicarbonate. A gas containing a high carbon monoxide to hydrogen ratio, as is present in a typical gasifer product, is contacted with the solution for the preferential production of ethanol with minimal water as a byproduct. Fractionation of the reaction solution provides substantially pure ethanol product and allows return of the catalysts for reuse.

Palladium and palladium-tin supported on multi wall carbon nanotubes or carbon for alkaline direct ethanol fuel cell

NASA Astrophysics Data System (ADS)

Geraldes, Adriana Napoleão; Furtunato da Silva, Dionisio; Martins da Silva, Júlio César; Antonio de Sá, Osvaldo; Spinacé, Estevam Vitório; Neto, Almir Oliveira; Coelho dos Santos, Mauro

2015-02-01

Pd and PdSn (Pd:Sn atomic ratios of 90:10), supported on Multi Wall Carbon Nanotubes (MWCNT) or Carbon (C), are prepared by an electron beam irradiation reduction method. The obtained materials are characterized by X-Ray diffraction (XRD), Energy dispersive X-ray analysis (EDX), Transmission electron Microscopy (TEM) and Cyclic Voltammetry (CV). The activity for ethanol electro-oxidation is tested in alkaline medium, at room temperature, using Cyclic Voltammetry and Chronoamperometry (CA) and in a single alkaline direct ethanol fuel cell (ADEFC), in the temperature range of 60-90 °C. CV analysis finds that Pd/MWCNT and PdSn/MWCNT presents onset potentials changing to negative values and high current values, compared to Pd/C and PdSn/C electrocatalysts. ATR-FTIR analysis, performed during the CV, identifies acetate and acetaldehyde as principal products formed during the ethanol electro-oxidation, with low conversion to CO2. In single fuel cell tests, at 85 °C, using 2.0 mol L-1 ethanol in 2.0 mol L-1 KOH solutions, the electrocatalysts supported on MWCNT, also, show higher power densities, compared to the materials supported on carbon: PdSn/MWCNT, presents the best result (36 mW cm-2). The results show that the use of MWCNT, instead of carbon, as support, plus the addition of small amounts of Sn to Pd, improves the electrocatalytic activity for Ethanol Oxidation Reaction (EOR).

Ethanol-assisted gel chromatography for single-chirality separation of carbon nanotubes.

PubMed

Zeng, Xiang; Hu, Jinwen; Zhang, Xiao; Zhou, Naigen; Zhou, Weiya; Liu, Huaping; Xie, Sishen

2015-10-21

Surfactants or polymers are usually used for the liquid processing of carbon nanotubes for their structure separation. However, they are difficult to remove after separation, affecting the intrinsic properties and applications of the separated species. Here, we report an ethanol-assisted gel chromatography for the chirality separation of single-walled carbon nanotubes (SWCNTs), in which ethanol is employed to finely tune the density/coverage of sodium dodecyl sulfate (SDS) on nanotubes, and thus the interactions between SWCNTs and an allyl dextran-based gel. Incrementally increasing the ethanol content in a low-concentration SDS eluent leads to successive desorption of the different structure SWCNTs adsorbed on the gel, and to achieve multiple distinct (n, m) single-chirality species. The use of ethanol enables the working concentration of SDS to be reduced dramatically and also avoids the introduction of other surfactants or chemical reagents. More importantly, ethanol can be easily removed after separation. The ability of ethanol to tune the interactions between SWCNTs and the gel also gives a deeper insight into the separation mechanism of SWCNTs using gel chromatography.

Ethanol-assisted gel chromatography for single-chirality separation of carbon nanotubes

NASA Astrophysics Data System (ADS)

Zeng, Xiang; Hu, Jinwen; Zhang, Xiao; Zhou, Naigen; Zhou, Weiya; Liu, Huaping; Xie, Sishen

2015-10-01

Surfactants or polymers are usually used for the liquid processing of carbon nanotubes for their structure separation. However, they are difficult to remove after separation, affecting the intrinsic properties and applications of the separated species. Here, we report an ethanol-assisted gel chromatography for the chirality separation of single-walled carbon nanotubes (SWCNTs), in which ethanol is employed to finely tune the density/coverage of sodium dodecyl sulfate (SDS) on nanotubes, and thus the interactions between SWCNTs and an allyl dextran-based gel. Incrementally increasing the ethanol content in a low-concentration SDS eluent leads to successive desorption of the different structure SWCNTs adsorbed on the gel, and to achieve multiple distinct (n, m) single-chirality species. The use of ethanol enables the working concentration of SDS to be reduced dramatically and also avoids the introduction of other surfactants or chemical reagents. More importantly, ethanol can be easily removed after separation. The ability of ethanol to tune the interactions between SWCNTs and the gel also gives a deeper insight into the separation mechanism of SWCNTs using gel chromatography.Surfactants or polymers are usually used for the liquid processing of carbon nanotubes for their structure separation. However, they are difficult to remove after separation, affecting the intrinsic properties and applications of the separated species. Here, we report an ethanol-assisted gel chromatography for the chirality separation of single-walled carbon nanotubes (SWCNTs), in which ethanol is employed to finely tune the density/coverage of sodium dodecyl sulfate (SDS) on nanotubes, and thus the interactions between SWCNTs and an allyl dextran-based gel. Incrementally increasing the ethanol content in a low-concentration SDS eluent leads to successive desorption of the different structure SWCNTs adsorbed on the gel, and to achieve multiple distinct (n, m) single-chirality species. The use of ethanol enables the working concentration of SDS to be reduced dramatically and also avoids the introduction of other surfactants or chemical reagents. More importantly, ethanol can be easily removed after separation. The ability of ethanol to tune the interactions between SWCNTs and the gel also gives a deeper insight into the separation mechanism of SWCNTs using gel chromatography. Electronic supplementary information (ESI) available: Fig. S1-S13, additional discussion and experimental details. See DOI: 10.1039/c5nr04116c

Continuous ethanol fermentation of lactose by a recombinant flocculating Saccharomyces cerevisiae strain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Domingues, L.; Dantas, M.M.; Lima, N.

1999-09-20

Alcohol fermentation of lactose was investigated using a recombinant flocculating Saccharomyces cetevisiae, expressing the LAC4 (coding the {beta}-galactosidase) and LAC12 (coding for lactose permease) genes of Kluyveromyces marxianus. Data on yeast fermentation and growth on a medium containing lactose as the sole carbon source are presented. In the range of studied lactose concentrations, total lactose consumption was observed with a conversion yield of ethanol close to the expected theoretical value. For the continuously operating bioreactor, an ethanol productivity of 11 g L{sup {minus}1} h{sup {minus}1} (corresponding to a feed lactose concentration of 50 g L{sup {minus}1} and a dilution ratemore » of 0.55 h{sup {minus}1}) was obtained, which is 7 times larger than the continuous conventional systems. The system stability was confirmed by keeping it in operation for 6 months.« less

Green hydrophilic interaction chromatography using ethanol-water-carbon dioxide mixtures.

PubMed

Pereira, Alberto dos Santos; Girón, Ana Jiménez; Admasu, Engdawork; Sandra, Pat

2010-03-01

In hydrophilic interaction chromatography (HILIC), best results are obtained with high concentrations of acetonitrile. In the framework of green chromatography, different concentrations of carbon dioxide were added to the mobile phases acetonitrile-water and ethanol-water and the impact on retention and separation in HILIC using bare silica as stationary phase was explored. The features of HILIC using enhanced-fluidity mobile phases are illustrated with the analysis of the nucleobases and a mixture containing the nucleobases and cortisol, flurbiprofen, theophylline and caffeine. For both organic constituents, the elution window is widened in function of the carbon dioxide concentration and selectivity changes. At high concentrations of carbon dioxide in ethanol, separations were similar to those obtained with acetonitrile without carbon dioxide addition.

Repeated batch fermentation of immobilized E. coli expressing Vitreoscilla hemoglobin for long-term use

PubMed Central

Sar, Taner; Seker, Gamze; Erman, Ayse Gokce; Stark, Benjamin C.; Yesilcimen Akbas, Meltem

2017-01-01

ABSTRACT This study describes an efficient and reusable process for ethanol production from medium containing whey powder, using alginate immobilized ethanologenic E. coli strains either expressing (TS3) or not expressing (FBR5) Vitreoscilla hemoglobin. Reuseabilities of the FBR5 and TS3 strains were investigated regarding their ethanol production capacities over the course of 15 successive 96-h batch fermentations. The ethanol production was fairly stable over the entire duration of the experiment, with strain TS3 maintaining a substantial advantage over strain FBR5. Storage of both strains in 2 different solutions for up to 60 d resulted in only a modest loss of ethanol production, with strain TS3 consistently outperforming strain FBR5 by a substantial amount. Strains stored for 15 or 30 d maintained their abilities to produce ethanol without dimunition over the course of 8 successive batch fermentations; again strain TS3 maintained a substantial advantage over strain FBR5 throughout the entire experiment. Thus, immobilization is a useful strategy to maintain the advantage in ethanol productivity afforded by expression of Vitreoscilla hemoglobin over long periods of time and large numbers of repeated batch fermentations, including, as in this case, using media with food processing wastes as the carbon source. PMID:28394725

Repeated batch fermentation of immobilized E. coli expressing Vitreoscilla hemoglobin for long-term use.

PubMed

Sar, Taner; Seker, Gamze; Erman, Ayse Gokce; Stark, Benjamin C; Yesilcimen Akbas, Meltem

2017-09-03

This study describes an efficient and reusable process for ethanol production from medium containing whey powder, using alginate immobilized ethanologenic E. coli strains either expressing (TS3) or not expressing (FBR5) Vitreoscilla hemoglobin. Reuseabilities of the FBR5 and TS3 strains were investigated regarding their ethanol production capacities over the course of 15 successive 96-h batch fermentations. The ethanol production was fairly stable over the entire duration of the experiment, with strain TS3 maintaining a substantial advantage over strain FBR5. Storage of both strains in 2 different solutions for up to 60 d resulted in only a modest loss of ethanol production, with strain TS3 consistently outperforming strain FBR5 by a substantial amount. Strains stored for 15 or 30 d maintained their abilities to produce ethanol without dimunition over the course of 8 successive batch fermentations; again strain TS3 maintained a substantial advantage over strain FBR5 throughout the entire experiment. Thus, immobilization is a useful strategy to maintain the advantage in ethanol productivity afforded by expression of Vitreoscilla hemoglobin over long periods of time and large numbers of repeated batch fermentations, including, as in this case, using media with food processing wastes as the carbon source.

Enhanced ethanol fermentation by engineered Saccharomyces cerevisiae strains with high spermidine contents.

PubMed

Kim, Sun-Ki; Jo, Jung-Hyun; Jin, Yong-Su; Seo, Jin-Ho

2017-05-01

Construction of robust and efficient yeast strains is a prerequisite for commercializing a biofuel production process. We have demonstrated that high intracellular spermidine (SPD) contents in Saccharomyces cerevisiae can lead to improved tolerance against various fermentation inhibitors, including furan derivatives and acetic acid. In this study, we examined the potential applicability of the S. cerevisiae strains with high SPD contents under two cases of ethanol fermentation: glucose fermentation in repeated-batch fermentations and xylose fermentation in the presence of fermentation inhibitors. During the sixteen times of repeated-batch fermentations using glucose as a sole carbon source, the S. cerevisiae strains with high SPD contents maintained higher cell viability and ethanol productivities than a control strain with lower SPD contents. Specifically, at the sixteenth fermentation, the ethanol productivity of a S. cerevisiae strain with twofold higher SPD content was 31% higher than that of the control strain. When the SPD content was elevated in an engineered S. cerevisiae capable of fermenting xylose, the resulting S. cerevisiae strain exhibited much 40-50% higher ethanol productivities than the control strain during the fermentations of synthetic hydrolysate containing high concentrations of fermentation inhibitors. These results suggest that the strain engineering strategy to increase SPD content is broadly applicable for engineering yeast strains for robust and efficient production of ethanol.

Identification and characterization of an anaerobic ethanol-producing cellulolytic bacterial consortium from Great Basin hot springs with agricultural residues and energy crops.

PubMed

Zhao, Chao; Deng, Yunjin; Wang, Xingna; Li, Qiuzhe; Huang, Yifan; Liu, Bin

2014-09-01

In order to obtain the cellulolytic bacterial consortia, sediments from Great Basin hot springs (Nevada, USA) were sampled and enriched with cellulosic biomass as the sole carbon source. The bacterial composition of the resulting anaerobic ethanol-producing celluloytic bacterial consortium, named SV79, was analyzed. With methods of the full-length 16S rRNA librarybased analysis and denaturing gradient gel electrophoresis, 21 bacteria belonging to eight genera were detected from this consortium. Clones with closest relation to the genera Acetivibrio, Clostridium, Cellulosilyticum, Ruminococcus, and Sporomusa were predominant. The cellulase activities and ethanol productions of consortium SV79 using different agricultural residues (sugarcane bagasse and spent mushroom substrate) and energy crops (Spartina anglica, Miscanthus floridulus, and Pennisetum sinese Roxb) were studied. During cultivation, consortium SV79 produced the maximum filter paper activity (FPase, 9.41 U/ml), carboxymethylcellulase activity (CMCase, 6.35 U/ml), and xylanase activity (4.28 U/ml) with sugarcane bagasse, spent mushroom substrate, and S. anglica, respectively. The ethanol production using M. floridulus as substrate was up to 2.63 mM ethanol/g using gas chromatography analysis. It has high potential to be a new candidate for producing ethanol with cellulosic biomass under anoxic conditions in natural environments.

Effect of oxygen and hydrogen on microstructure of pyrolytic carbon deposited from thermal decomposition of methane and ethanol

NASA Astrophysics Data System (ADS)

Ren, Biyun; Zhang, Shouyang; He, LiQun; Gu, Shengyue

2018-05-01

Chemical vapor infiltration (CVI) is the most extensive industrial preparation of carbon/carbon (C/C) composites. Precursor affects the CVI process considerably. In the present study, using carbon fiber bundles as preforms, methane and ethanol as precursors, the C/C composites were densified by decomposition of various gases in CVI. The thickness and texture of deposited pyrolytic carbon (PyC) were characterized by polarized light microscopy (PLM). The microstructure of PyC was analyzed by Raman spectroscopy. The morphologies of PyC were characterized by scanning electron microscopy (SEM). The composition of PyC was detected by X-ray photoelectron spectroscopy (XPS). Adding hydrogen in methane precursor resulted in a sharp decrease in the deposition rate and texture of PyC. Mixture of methane and ethanol as the precursor improved the deposition rate and texture remarkably. Besides, O element in ethanol was not remained as a constitution of PyC, and it was removed before the formation of PyC.

Nano-spike Catalysts Convert Carbon Dioxide Directly into Ethanol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rondinone, Adam

2016-10-12

In a new twist to waste-to-fuel technology, scientists at the Department of Energy’s Oak Ridge National Laboratory have developed an electrochemical process that uses tiny spikes of carbon and copper to turn carbon dioxide, a greenhouse gas, into ethanol. Their finding, which involves nanofabrication and catalysis science, was serendipitous.

Production of ethanol from thin stillage by metabolically engineered Escherichia coli.

PubMed

Gonzalez, Ramon; Campbell, Paul; Wong, Matthew

2010-03-01

Thin stillage is a by-product generated in large amounts during the production of ethanol that is rich in carbon sources like glycerol, glucose and maltose. Unfortunately, the fermentation of thin stillage results in a mixture of organic acids and ethanol and minimum utilization of glycerol, the latter a compound that can represent up to 80% of the available substrates in this stream. We report here the efficient production of ethanol from thin stillage by a metabolically engineered strain of Escherichia coli. Simultaneous utilization of glycerol and sugars was achieved by overexpressing either the fermentative or the respiratory glycerol-utilization pathway. However, amplification of the fermentative pathway (encoded by gldA and dhaKLM) led to more efficient consumption of glycerol and promoted the synthesis of reduced products, including ethanol. A previously constructed strain, EH05, containing mutations that prevented the accumulation of competing by-products (i.e. lactate, acetate, and succinate) and overexpressing the fermentative pathway for glycerol utilization [i.e. strain EH05 (pZSKLMgldA)], efficiently converted thin stillage supplemented with only mineral salts to ethanol at yields close to 85% of the theoretical maximum. Ethanol accounted for about 90% (w/w) of the product mixture. These results, along with the comparable performance of strain EH05 (pZSKLMgldA) in 0.5 and 5 l fermenters, indicate a great potential for the adoption of this process by the biofuels industry.

Production of ethanol and arabitol by Debaryomyces nepalensis: influence of process parameters

PubMed Central

2013-01-01

Debaryomyces nepalensis, osmotolerant yeast isolated from rotten apple, is known to utilize both hexoses and pentoses and produce industrially important metabolites like ethanol, xylitol and arabitol. In the present study, the effect of different growth substrates, trace elements, nitrogen concentration and initial pH on growth and formation of ethanol and arabitol were examined. Optimum conditions for maximizing the product yields were established: glucose as carbon source, an initial pH of 6.0, 6 g/L of ammonium sulphate and addition of micronutrients. Under these best suited conditions, a concentration of 11g/L of arabitol and 19 g/L of ethanol was obtained in shake flask fermentations. The fermentation was scaled up to 2.5 L bioreactor and the influence of aeration, agitation and initial substrate concentration was also determined. Under optimal conditions (150 g/L glucose, 400 rpm and 0.5 vvm) ethanol concentration reached 52 g/L, which corresponds to a yield of 0.34 g/g and volumetric productivity of 0.28 g/L/h, whereas arabitol production reached a maximum of 14 g/L with a yield and volumetric productivity of 0.1 g/g and 0.07 g/L/h respectively. PMID:23659479

Critical fluid extraction of Juniperus virginiana L. and bioactivity of extracts against subterranean termites and wood-rot fungi.

Treesearch

F. J. Eller; Carol A. Clausen; Frederick Green; S.L. Taylor

2010-01-01

Eastern red cedar (Juniperus virginiana L.) is an abundant renewable resource and represents a vast potential source of valuable natural products that may serve as natural biocides. Both the wood and needles from J. virginiana were extracted using liquid carbon dioxide (L-CO2) as well as ethanol (EtOH) and the yields determined.Woodblocks were...

Amperometric sensor for ethanol based on one-step electropolymerization of thionine-carbon nanofiber nanocomposite containing alcohol oxidase.

PubMed

Wu, Lina; McIntosh, Mike; Zhang, Xueji; Ju, Huangxian

2007-12-15

Thionine had strong interaction with carbon nanofiber (CNF) and was used in the non-covalent functionalization of carbon nanofiber for the preparation of stable thionine-CNF nanocomposite with good dispersion. With a simple one-step electrochemical polymerization of thionine-CNF nanocomposite and alcohol oxidase (AOD), a stable poly(thionine)-CNF/AOD biocomposite film was formed on electrode surface. Based on the excellent catalytic activity of the biocomposite film toward reduction of dissolved oxygen, a sensitive ethanol biosensor was proposed. The ethanol biosensor could monitor ethanol ranging from 2.0 to 252 microM with a detection limit of 1.7 microM. It displayed a rapid response, an expanded linear response range as well as excellent reproducibility and stability. The combination of catalytic activity of CNF and the promising feature of the biocomposite with one-step non-manual technique favored the sensitive determination of ethanol with improved analytical capabilities.

Quantifying impacts on air quality of vehicular emissions in Sao Paulo and Rio de Janeiro

NASA Astrophysics Data System (ADS)

Artaxo, Paulo; Ferreira de Brito, Joel; Godoy, José Marcus; Luiza Godoy, Maria; Junior, Djacinto

2016-04-01

Vehicular emissions in megacities such as Sao Paulo and Rio de Janeiro are increasingly becoming a global issue. The São Paulo Metropolitan Area (SPMA), located in Southeast of Brazil, is a megacity with a population of 18 million people, with 7 million cars and large-scale industrial emissions. Rio de Janeiro is also a large city with different meteorology than São Paulo. All cars in Brazil runs gasohol, with 23% ethanol in gasoline, and for the last 10 years, flex cars that can run on gasohol, ethanol or any mixture dominate the market. Overall ethanol accounts for about 30-40% of fuel burned in both cities. To improve the understanding of vehicular emission impacts on aerosol composition and life cycle in these two large megacities a source apportionment study, combining online and offline measurements, was performed. Aerosols were collected for one year to capture seasonal variability at 4 sites in each city, with inorganic and organic aerosol component being sampled. Organic and elemental carbon were measured using a Sunset Laboratory Dual Optics (transmission and reflectance) Carbon Analyzer and about 22 trace elements has been measured using polarized X-Ray Fluorescence (XRF). Aerosol mass and black carbon were also measured, as well as trace gases to help in aerosol source apportionment. In Sao Paulo, the average PM2.5 mass concentration obtained varied from 9.6 to 12.2 μg m-3 for the several sites, and similar concentrations were measured in Rio de Janeiro. At all sites, organic matter (OM) has dominated fine mode aerosol concentration with 42 to 60% of the aerosol mass. EC accounted for 21 to 31% of fine mode aerosol mass concentration. Sulfate accounted for 21 to 26% of PM2.5 for the sites. Aerosol source apportionment was done with receptor analysis and integration with online data such as PTR-MS, Aethalometers, Nephelometers and ACSM helped to apportion vehicular emissions. For the 8 sites operated in Sao Paulo and Rio de Janeiro, vehicular emissions accounts for about 63% of PM2.5. Results are very similar for the different sites and cities.

Estimating the potential of energy saving and carbon emission mitigation of cassava-based fuel ethanol using life cycle assessment coupled with a biogeochemical process model.

PubMed

Jiang, Dong; Hao, Mengmeng; Fu, Jingying; Tian, Guangjin; Ding, Fangyu

2017-09-14

Global warming and increasing concentration of atmospheric greenhouse gas (GHG) have prompted considerable interest in the potential role of energy plant biomass. Cassava-based fuel ethanol is one of the most important bioenergy and has attracted much attention in both developed and developing countries. However, the development of cassava-based fuel ethanol is still faced with many uncertainties, including raw material supply, net energy potential, and carbon emission mitigation potential. Thus, an accurate estimation of these issues is urgently needed. This study provides an approach to estimate energy saving and carbon emission mitigation potentials of cassava-based fuel ethanol through LCA (life cycle assessment) coupled with a biogeochemical process model-GEPIC (GIS-based environmental policy integrated climate) model. The results indicate that the total potential of cassava yield on marginal land in China is 52.51 million t; the energy ratio value varies from 0.07 to 1.44, and the net energy surplus of cassava-based fuel ethanol in China is 92,920.58 million MJ. The total carbon emission mitigation from cassava-based fuel ethanol in China is 4593.89 million kgC. Guangxi, Guangdong, and Fujian are identified as target regions for large-scale development of cassava-based fuel ethanol industry. These results can provide an operational approach and fundamental data for scientific research and energy planning.

Estimating the potential of energy saving and carbon emission mitigation of cassava-based fuel ethanol using life cycle assessment coupled with a biogeochemical process model

NASA Astrophysics Data System (ADS)

Jiang, Dong; Hao, Mengmeng; Fu, Jingying; Tian, Guangjin; Ding, Fangyu

2017-09-01

Global warming and increasing concentration of atmospheric greenhouse gas (GHG) have prompted considerable interest in the potential role of energy plant biomass. Cassava-based fuel ethanol is one of the most important bioenergy and has attracted much attention in both developed and developing countries. However, the development of cassava-based fuel ethanol is still faced with many uncertainties, including raw material supply, net energy potential, and carbon emission mitigation potential. Thus, an accurate estimation of these issues is urgently needed. This study provides an approach to estimate energy saving and carbon emission mitigation potentials of cassava-based fuel ethanol through LCA (life cycle assessment) coupled with a biogeochemical process model—GEPIC (GIS-based environmental policy integrated climate) model. The results indicate that the total potential of cassava yield on marginal land in China is 52.51 million t; the energy ratio value varies from 0.07 to 1.44, and the net energy surplus of cassava-based fuel ethanol in China is 92,920.58 million MJ. The total carbon emission mitigation from cassava-based fuel ethanol in China is 4593.89 million kgC. Guangxi, Guangdong, and Fujian are identified as target regions for large-scale development of cassava-based fuel ethanol industry. These results can provide an operational approach and fundamental data for scientific research and energy planning.

Proteins involved in wine aroma compounds metabolism by a Saccharomyces cerevisiae flor-velum yeast strain grown in two conditions.

PubMed

Moreno-García, Jaime; García-Martínez, Teresa; Millán, M Carmen; Mauricio, Juan Carlos; Moreno, Juan

2015-10-01

A proteomic and exometabolomic study was conducted on Saccharomyces cerevisiae flor yeast strain growing under biofilm formation condition (BFC) with ethanol and glycerol as carbon sources and results were compared with those obtained under no biofilm formation condition (NBFC) containing glucose as carbon source. By using modern techniques, OFFGEL fractionator and LTQ-Orbitrap for proteome and SBSE-TD-GC-MS for metabolite analysis, we quantified 84 proteins including 33 directly involved in the metabolism of glycerol, ethanol and 17 aroma compounds. Contents in acetaldehyde, acetic acid, decanoic acid, 1,1-diethoxyethane, benzaldehyde and 2-phenethyl acetate, changed above their odor thresholds under BFC, and those of decanoic acid, ethyl octanoate, ethyl decanoate and isoamyl acetate under NBFC. Of the twenty proteins involved in the metabolism of ethanol, acetaldehyde, acetoin, 2,3-butanediol, 1,1-diethoxyethane, benzaldehyde, organic acids and ethyl esters, only Adh2p, Ald4p, Cys4p, Fas3p, Met2p and Plb1p were detected under BFC and as many Acs2p, Ald3p, Cem1p, Ilv2p, Ilv6p and Pox1p, only under NBFC. Of the eight proteins involved in glycerol metabolism, Gut2p was detected only under BFC while Pgs1p and Rhr2p were under NBFC. Finally, of the five proteins involved in the metabolism of higher alcohols, Thi3p was present under BFC, and Aro8p and Bat2p were under NBFC. Copyright © 2015 Elsevier Ltd. All rights reserved.

Xylose isomerase improves growth and ethanol production rates from biomass sugars for both Saccharomyces pastorianus and Saccharomyces cerevisiae.

PubMed

Miller, Kristen P; Gowtham, Yogender Kumar; Henson, J Michael; Harcum, Sarah W

2012-01-01

The demand for biofuel ethanol made from clean, renewable nonfood sources is growing. Cellulosic biomass, such as switch grass (Panicum virgatum L.), is an alternative feedstock for ethanol production; however, cellulosic feedstock hydrolysates contain high levels of xylose, which needs to be converted to ethanol to meet economic feasibility. In this study, the effects of xylose isomerase on cell growth and ethanol production from biomass sugars representative of switch grass were investigated using low cell density cultures. The lager yeast species Saccharomyces pastorianus was grown with immobilized xylose isomerase in the fermentation step to determine the impact of the glucose and xylose concentrations on the ethanol production rates. Ethanol production rates were improved due to xylose isomerase; however, the positive effect was not due solely to the conversion of xylose to xylulose. Xylose isomerase also has glucose isomerase activity, so to better understand the impact of the xylose isomerase on S. pastorianus, growth and ethanol production were examined in cultures provided fructose as the sole carbon. It was observed that growth and ethanol production rates were higher for the fructose cultures with xylose isomerase even in the absence of xylose. To determine whether the positive effects of xylose isomerase extended to other yeast species, a side-by-side comparison of S. pastorianus and Saccharomyces cerevisiae was conducted. These comparisons demonstrated that the xylose isomerase increased ethanol productivity for both the yeast species by increasing the glucose consumption rate. These results suggest that xylose isomerase can contribute to improved ethanol productivity, even without significant xylose conversion. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

Hydrolysis of Agave fourcroydes Lemaire (henequen) leaf juice and fermentation with Kluyveromyces marxianus for ethanol production

PubMed Central

2014-01-01

Background Carbon sources for biofuel production are wide-ranging and their availability depends on the climate and soil conditions of the land where the production chain is located. Henequen (Agave fourcroydes Lem.) is cultivated in Yucatán, Mexico to produce natural fibers from the leaves, and a juice containing fructans is produced during this process. Fructans can be hydrolyzed to fructose and glucose and metabolized into ethanol by appropriate yeasts. In Mexico, different Agave species provide the carbon source for (distilled and non-distilled) alcoholic beverage production using the stem of the plant, whilst the leaves are discarded. In this work, we investigated the effect of thermal acid and enzymatic hydrolysis of the juice on the amount of reducing sugars released. Growth curves were generated with the yeasts Saccharomyces cerevisiae and Kluyveromyces marxianus and fermentations were then carried out with Kluyveromyces marxianus to determine alcohol yields. Results With thermal acid hydrolysis, the greatest increase in reducing sugars (82.6%) was obtained using 5% H2SO4 at 100°C with a 30 min reaction time. Statistically similar results can be obtained using the same acid concentration at a lower temperature and with a shorter reaction time (60°C, 15 min), or by using 1% H2SO4 at 100°C with a 30 min reaction time. In the case of enzymatic hydrolysis, the use of 5.75, 11.47 and 22.82 U of enzyme did not produce significant differences in the increase in reducing sugars. Although both hydrolysis processes obtained similar results, the difference was observed after fermentation. Ethanol yields were 50.3 ± 4 and 80.04 ± 5.29% of the theoretical yield respectively. Conclusions Final reducing sugars concentrations obtained with both thermal acid and enzymatic hydrolysis were similar. Saccharomyces cerevisiae, a good ethanol producer, did not grow in the hydrolysates. Only Kluyveromyces marxianus was able to grow in them, giving a higher ethanol yield with the enzymatic hydrolysate. The leaves account for a non-negligible weight of the total agave plant biomass, so this work complements the knowledge already developed on agave fermentations by making it possible to produce ethanol from almost the entire plant (stem and leaves). PMID:24529165

Quantification of ethanol in plasma by electrochemical detection with an unmodified screen printed carbon electrode

NASA Astrophysics Data System (ADS)

Tian, Gang; Zhang, Xiao-Qing; Zhu, Ming-Song; Zhang, Zhong; Shi, Zheng-Hu; Ding, Min

2016-03-01

Simple, rapid and accurate detection of ethanol concentration in blood is very crucial in the diagnosis and management of potential acute ethanol intoxication patients. A novel electrochemical detection method was developed for the quantification of ethanol in human plasma with disposable unmodified screen-printed carbon electrode (SPCE) without sample preparation procedure. Ethanol was detected indirectly by the reaction product of ethanol dehydrogenase (ADH) and cofactor nicotinamide adenine dinucleotide (NAD+). Method validation indicated good quantitation precisions with intra-day and inter-day relative standard deviations of ≤9.4% and 8.0%, respectively. Ethanol concentration in plasma is linear ranging from 0.10 to 3.20 mg/mL, and the detection limit is 40.0 μg/mL (S/N > 3). The method shows satisfactory correlation with the reference method of headspace gas chromatography in twenty human plasma samples (correlation coefficient 0.9311). The proposed method could be applied to diagnose acute ethanol toxicity or ethanol-related death.

Quantification of ethanol in plasma by electrochemical detection with an unmodified screen printed carbon electrode

PubMed Central

Tian, Gang; Zhang, Xiao-Qing; Zhu, Ming-Song; Zhang, Zhong; Shi, Zheng-Hu; Ding, Min

2016-01-01

Simple, rapid and accurate detection of ethanol concentration in blood is very crucial in the diagnosis and management of potential acute ethanol intoxication patients. A novel electrochemical detection method was developed for the quantification of ethanol in human plasma with disposable unmodified screen-printed carbon electrode (SPCE) without sample preparation procedure. Ethanol was detected indirectly by the reaction product of ethanol dehydrogenase (ADH) and cofactor nicotinamide adenine dinucleotide (NAD+). Method validation indicated good quantitation precisions with intra-day and inter-day relative standard deviations of ≤9.4% and 8.0%, respectively. Ethanol concentration in plasma is linear ranging from 0.10 to 3.20 mg/mL, and the detection limit is 40.0 μg/mL (S/N > 3). The method shows satisfactory correlation with the reference method of headspace gas chromatography in twenty human plasma samples (correlation coefficient 0.9311). The proposed method could be applied to diagnose acute ethanol toxicity or ethanol-related death. PMID:27006081

Measuring the Effect of Fuel Structures and Blend Distribution on Diesel Emissions Using Isotope Tracing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, A S; Mueller, C J; Buchholz, B A

2004-02-10

Carbon atoms occupying specific positions within fuel molecules can be labeled and followed in emissions. Renewable bio-derived fuels possess a natural uniform carbon-14 ({sup 14}C) tracer several orders of magnitude above petroleum-derived fuels. These fuels can be used to specify sources of carbon in particulate matter (PM) or other emissions. Differences in emissions from variations in the distribution of a fuel component within a blend can also be measured. Using Accelerator Mass Spectrometry (AMS), we traced fuel components with biological {sup 14}C/C levels of 1 part in 10{sup 12} against a {sup 14}C-free petroleum background in PM and CO{sub 2}.more » Different carbon atoms in the ester structure of the diesel oxygenate dibutyl maleate displayed far different propensities to produce PM. Homogeneous cosolvent and heterogeneous emulsified ethanol-in-diesel blends produced significantly different PM despite having the same oxygen content in the fuel. Emulsified blends produced PM with significantly more volatile species. Although ethanol-derived carbon was less likely to produce PM than diesel fuel, it formed non-volatile structures when it resided in PM. The contribution of lubrication oil to PM was determined by measuring an isotopic difference between 100% bio-diesel and the PM it produced. Data produced by the experiments provides validation for combustion models.« less

Life cycle assessment of greenhouse gas emissions from plug-in hybrid vehicles: implications for policy.

PubMed

Samaras, Constantine; Meisterling, Kyle

2008-05-01

Plug-in hybrid electric vehicles (PHEVs), which use electricity from the grid to power a portion of travel, could play a role in reducing greenhouse gas (GHG) emissions from the transport sector. However, meaningful GHG emissions reductions with PHEVs are conditional on low-carbon electricity sources. We assess life cycle GHG emissions from PHEVs and find that they reduce GHG emissions by 32% compared to conventional vehicles, but have small reductions compared to traditional hybrids. Batteries are an important component of PHEVs, and GHGs associated with lithium-ion battery materials and production account for 2-5% of life cycle emissions from PHEVs. We consider cellulosic ethanol use and various carbon intensities of electricity. The reduced liquid fuel requirements of PHEVs could leverage limited cellulosic ethanol resources. Electricity generation infrastructure is long-lived, and technology decisions within the next decade about electricity supplies in the power sector will affectthe potential for large GHG emissions reductions with PHEVs for several decades.

Nano-spike Catalysts Convert Carbon Dioxide Directly into Ethanol

ScienceCinema

Rondinone, Adam

2018-06-12

In a new twist to waste-to-fuel technology, scientists at the Department of Energy’s Oak Ridge National Laboratory have developed an electrochemical process that uses tiny spikes of carbon and copper to turn carbon dioxide, a greenhouse gas, into ethanol. Their finding, which involves nanofabrication and catalysis science, was serendipitous.

Enhancing ethanol yields through d-xylose and l-arabinose co-fermentation after construction of a novel high efficient l-arabinose-fermenting Saccharomyces cerevisiae strain.

PubMed

Caballero, Antonio; Ramos, Juan Luis

2017-04-01

Lignocellulose contains two pentose sugars, l-arabinose and d-xylose, neither of which is naturally fermented by first generation (1G) ethanol-producing Saccharomyces cerevisiae yeast. Since these sugars are inaccessible to 1G yeast, a significant percentage of the total carbon in bioethanol production from plant residues, which are used in second generation (2G) ethanol production, remains unused. Recombinant Saccharomyces cerevisiae strains capable of fermenting d-xylose are available on the market; however, there are few examples of l-arabinose-fermenting yeasts, and commercially, there are no strains capable of fermenting both d-xylose and l-arabinose because of metabolic incompatibilities when both metabolic pathways are expressed in the same cell. To attempt to solve this problem we have tested d-xylose and l-arabinose co-fermentation. To find efficient alternative l-arabinose utilization pathways to the few existing ones, we have used stringent methodology to screen for new genes (metabolic and transporter functions) to facilitate l-arabinose fermentation in recombinant yeast. We demonstrate the feasibility of this approach in a successfully constructed yeast strain capable of using l-arabinose as the sole carbon source and capable of fully transforming it to ethanol, reaching the maximum theoretical fermentation yield (0.43 g g-1). We demonstrate that efficient co-fermentation of d-xylose and l-arabinose is feasible using two different co-cultured strains, and observed no fermentation delays, yield drops or accumulation of undesired byproducts. In this study we have identified a technically efficient strategy to enhance ethanol yields by 10 % in 2G plants in a process based on C5 sugar co-fermentation.

Perspectives on the production of polyhydroxyalkanoates in biorefineries associated with the production of sugar and ethanol.

PubMed

Silva, Luiziana Ferreira; Taciro, Marilda Keico; Raicher, Gil; Piccoli, Rosane Aparecida Moniz; Mendonça, Thatiane Teixeira; Lopes, Mateus Schreiner Garcez; Gomez, José Gregório Cabrera

2014-11-01

Polyhydroxyalkanoates (PHA) are biodegradable and biocompatible bacterial thermoplastic polymers that can be obtained from renewable resources. The high impact of the carbon source in the final cost of this polymer has been one of the major limiting factors for PHA production and agricultural residues, mainly lignocellulosic materials, have gained attention to overcome this problem. In Brazil, production of 2nd generation ethanol from the glucose fraction, derived from sugarcane bagasse hydrolysate has been studied. The huge amounts of remaining xylose will create an opportunity for the development of other bioprocesses, generating new products to be introduced into a biorefinery model. Although PHA production from sucrose integrated to a 1G ethanol and sugar mill has been proposed in the past, the integration of the process of 2G ethanol in the context of a biorefinery will provide enormous amounts of xylose, which could be applied to produce PHA, establishing a second-generation of PHA production process. Those aspects and perspectives are presented in this article. Copyright © 2014 Elsevier B.V. All rights reserved.

Headspace analysis of volatile organic compounds from ethanolic systems by direct APCI-MS

NASA Astrophysics Data System (ADS)

Aznar, Margarita; Tsachaki, Maroussa; Linforth, Robert S. T.; Ferreira, Vicente; Taylor, Andrew J.

2004-12-01

Measuring the dynamic release of aroma compounds from ethanolic solutions by direct gas phase mass spectrometry (MS) techniques is an important technique for flavor chemists but presents technical difficulties as the changing ethanol concentration in the source makes quantitative measurements impossible. The effect of adding ethanol into the source via the sweep gas (0-565 [mu]L ethanol/L N2), to act as the proton transfer reagent ion and thereby control ionization was studied. With increasing concentrations of ethanol in the source, the water ions were replaced by ethanol ions above 3.2 [mu]L/L. The effect of source ethanol on the ionization of eleven aroma compounds was then measured. Some compounds showed reduced signal (10-40%), others increased signal (150-400%) when ionized via ethanol reagent ions compared to water reagent ions. Noise also increased in most cases so there was no overall increase in sensitivity. Providing the ethanol concentration in the source was >6.5 [mu]L/L N2 and maintained at a fixed value, ionization was consistent and quantitative. The technique was successfully applied to measure the partition of the test volatile compounds from aqueous and 12% ethanol solutions at equilibrium. Ethanolic solutions decreased the partition coefficient of most of the aroma compounds, as a function of hydrophobicity.

Effects of ethanol-based fuel contamination: microbial community changes, production of regulated compounds, and methane generation.

PubMed

Nelson, Denice K; Lapara, Timothy M; Novak, Paige J

2010-06-15

Ethanol-based fuels are becoming more heavily used, increasing the likelihood of ethanol-based fuel spills during transportation and storage. Although ethanol is well-known to be readily biodegradable, very little is known about the effects that such a spill might have on an indigenous microbial community. Of particular concern is that ethanol contamination could stimulate the growth of organisms that can generate regulated compounds and/or produce explosive quantities of methane gas. A column-based study was performed to elucidate the potential impacts of ethanol-based fuel (E85) on the indigenous microbial community during a simulated fuel spill. A continuous dilute supply of E85 resulted in profound shifts in both the bacterial and archaeal communities. The shift was accompanied by the production of high concentrations of volatile fatty acids and butanol, a compound that is regulated in groundwater by some states. Results also indicated that a continuous feed of dilute E85 generated explosive levels of methane within one month of column operation. Quantitative PCR data showed a statistically significant increase in methanogenic populations when compared to a control column. The elevated population numbers correlated to areas of the column receiving a sustained carbon load. Toxicity data indicated that microbial growth was completely inhibited (as evidenced by absence of ethanol breakdown products) at ethanol levels above 6% (v/v). These data suggest that ethanol from ethanol-based fuel can be readily degraded, but can also produce metabolic products that are regulated as well as explosive levels of methane. The core of an E85 spill may serve as a long-term source of contamination as it cannot be degraded until significant dilution has occurred.

Biofiltration of volatile ethanol using sugar cane bagasse inoculated with Candida utilis.

PubMed

Christen, P; Domenech, F; Michelena, G; Auria, R; Revah, S

2002-01-28

Candida utilis (C. utilis) growing on sugar cane bagasse complemented with a mineral salt solution was studied for gaseous ethanol removal in a biofilter. Ethanol loads from 93.7 to 511.9 g/h m(3) were used, by varying both inlet ethanol concentration (9.72 to 52.4 g/m(3)) and air flow rate (1.59 x 10(-3) to 2.86 x 10(-3) m(3)/h). At a loading rate of 93.7 g/h m(3), a steady-state was maintained for 300 h. Ethanol removal was complete, and 76.3% of the carbon consumed was found in carbon dioxide. At an higher aeration rate (ethanol load=153.8 g/h m(3)), the biofilter displayed an average removal efficiency (RE) of 70%, and an elimination capacity (EC) of 107.7 g/h m(3). Only 64.4% of the carbon consumed was used for CO(2) production. Acetaldehyde and ethyl acetate in the outlet gas attained 7.86 and 20.4% in terms of carbon balance, respectively. In both cases, the transient phase was less than one day. At a high inlet ethanol concentration (52.4 g/m(3)), no steady-state was observed and the process stopped during the third day. In the three cases, final biomass was poor, ranging from 10.5 to 14.8 mg/g dm. Final pH 4.0-4.6, indicated that acidifying non-volatile metabolites, such as acetate, accumulated in the reactor.

The Deletion of the Succinate Dehydrogenase Gene KlSDH1 in Kluyveromyces lactis Does Not Lead to Respiratory Deficiency

PubMed Central

Saliola, Michele; Bartoccioni, Paola Chiara; De Maria, Ilaria; Lodi, Tiziana; Falcone, Claudio

2004-01-01

We have isolated a Kluyveromyces lactis mutant unable to grow on all respiratory carbon sources with the exception of lactate. Functional complementation of this mutant led to the isolation of KlSDH1, the gene encoding the flavoprotein subunit of the succinate dehydrogenase (SDH) complex, which is essential for the aerobic utilization of carbon sources. Despite the high sequence conservation of the SDH genes in Saccharomyces cerevisiae and K. lactis, they do not have the same relevance in the metabolism of the two yeasts. In fact, unlike SDH1, KlSDH1 was highly expressed under both fermentative and nonfermentative conditions. In addition to this, but in contrast with S. cerevisiae, K. lactis strains lacking KlSDH1 were still able to grow in the presence of lactate. In these mutants, oxygen consumption was one-eighth that of the wild type in the presence of lactate and was normal with glucose and ethanol, indicating that the respiratory chain was fully functional. Northern analysis suggested that alternative pathway(s), which involves pyruvate decarboxylase and the glyoxylate cycle, could overcome the absence of SDH and allow (i) lactate utilization and (ii) the accumulation of succinate instead of ethanol during growth on glucose. PMID:15189981

Efficient utilization of Eucheuma denticulatum hydrolysates using an activated carbon adsorption process for ethanol production in a 5-L fermentor.

PubMed

Ra, Chae Hun; Kim, Min Ji; Jeong, Gwi-Taek; Kim, Sung-Koo

2017-03-01

A total monosaccharide concentration of 37.8 g/L and 85.9% conversion from total fermentable monosaccharides of 44.0 g/L from 110 g dw/L Eucheuma denticulatum slurry were obtained by thermal acid hydrolysis and enzymatic saccharification. Subsequent adsorption treatment to remove 5-hydroxymethylfurfural (5-HMF) using 5% activated carbon and an adsorption time of 10 min were used to prevent a prolonged lag phase, reduced cell growth, and low ethanol production. The equilibrium adsorption capacity (q e ) of HMF (58.183 mg/g) showed high affinity to activated carbon comparing to those of galactose (2.466 mg/g) and glucose (2.474 mg/g). The efficiency of cell growth and ethanol production with activated carbon treatment was higher than that without activated carbon treatment. Fermentation using S. stipitis KCTC7228 produced a cell concentration of 3.58 g dw/L with Y X/S of 0.107, and an ethanol concentration of 15.8 g/L with Y P/S of 0.48 in 96 h.

Investigation of critical equivalence ratio and chemical speciation in flames of ethylbenzene-ethanol blends

DOE Office of Scientific and Technical Information (OSTI.GOV)

Therrien, Richard J.; Ergut, Ali; Levendis, Yiannis A.

This work investigates five different one-dimensional, laminar, atmospheric pressure, premixed ethanol/ethylbenzene flames (0%, 25%, 50%, 75% and 90% ethanol by weight) at their soot onset threshold ({phi}{sub critical}). Liquid ethanol/ethylbenzene mixtures were pre-vaporized in nitrogen, blended with an oxygen-nitrogen mixture and, upon ignition, burned in premixed one-dimensional flames at atmospheric pressure. The flames were controlled so that each was at its visual soot onset threshold, and all had similar temperature profiles (determined by thermocouples). Fixed gases, light volatile hydrocarbons, polycyclic aromatic hydrocarbons (PAH), and oxygenated aromatic hydrocarbons were directly sampled at three locations in each flame. The experimental results weremore » compared with a detailed kinetic model, and the modeling results were used to perform a reaction flux analysis of key species. The critical equivalence ratio was observed to increase in a parabolic fashion as ethanol concentration increased in the fuel mixture. The experimental results showed increasing trends of methane, ethane, and ethylene with increasing concentrations of ethanol in the flames. Carbon monoxide was also seen to increase significantly with the increase of ethanol in the flame, which removes carbon from the PAH and soot formation pathways. The PAH and oxygenated aromatic hydrocarbon values were very similar in the 0%, 25% and 50% ethanol flames, but significantly lower in the 75% and 90% ethanol flames. These results were in general agreement with the model and were reflected by the model soot predictions. The model predicted similar soot profiles for the 0%, 25% and 50% ethanol flames, however it predicted significantly lower values in the 75% and 90% ethanol flames. The reaction flux analysis revealed benzyl to be a major contributor to single and double ring aromatics (i.e., benzene and naphthalene), which was identified in a similar role in nearly sooting or highly sooting ethylbenzene flames. The presence of this radical was significantly reduced as ethanol concentration was increased in the flames, and this effect in combination with the lower carbon to oxygen ratios and the enhanced formation of carbon monoxide, are likely what allowed higher equivalence ratios to be reached without forming soot. (author)« less

Hydrogen production by ethanol steam reforming on Ni/oxide catalysts

NASA Astrophysics Data System (ADS)

Lazar, Mihaela D.; Dan, Monica; Mihet, Maria; Borodi, George; Almasan, Valer

2012-02-01

Hydrogen production from bio-fuels such as bio-ethanol provides significant environmental benefits since the resulted CO2 is consumed again for biomass growth, offering a carbon dioxide neutral energy source. In the actual conditions of increasing energy demand and atmosphere pollution, clean produced hydrogen can be an alternative option for a clean energy vector. In this paper we present the results obtained in hydrogen production by steam reforming of ethanol using oxide supported nickel catalysts. Although Ni is not the most active catalyst for this process, economically is the most attractive one, due to the high price and low availability of noble metals. Ni was dispersed on several oxides: ZrO2, Al2O3, Cr2O3, SiO2 with a target metal concentration of 8 wt%. using impregnation method. The catalysts were characterized using several techniques: N2 adsorption desorption isotherms to determine total surface area and porosity, XRD to determine oxide crystallinity and Ni crystallite size. Each catalyst was tested in steam reforming of ethanol at temperatures ranging from 150 to 350°C, at atmospheric pressure and a ethanol: steam ratio of 1:9. The best ethanol conversion and catalyst stability was obtained for Ni/Al2O3. The catalyst selectivity for H2 production depends on the support nature. The best H2 selectivity was obtained for Ni/ZrO2 catalyst.

Ethanol dehydration to ethylene in a stratified autothermal millisecond reactor.

PubMed

Skinner, Michael J; Michor, Edward L; Fan, Wei; Tsapatsis, Michael; Bhan, Aditya; Schmidt, Lanny D

2011-08-22

The concurrent decomposition and deoxygenation of ethanol was accomplished in a stratified reactor with 50-80 ms contact times. The stratified reactor comprised an upstream oxidation zone that contained Pt-coated Al(2)O(3) beads and a downstream dehydration zone consisting of H-ZSM-5 zeolite films deposited on Al(2)O(3) monoliths. Ethanol conversion, product selectivity, and reactor temperature profiles were measured for a range of fuel:oxygen ratios for two autothermal reactor configurations using two different sacrificial fuel mixtures: a parallel hydrogen-ethanol feed system and a series methane-ethanol feed system. Increasing the amount of oxygen relative to the fuel resulted in a monotonic increase in ethanol conversion in both reaction zones. The majority of the converted carbon was in the form of ethylene, where the ethanol carbon-carbon bonds stayed intact while the oxygen was removed. Over 90% yield of ethylene was achieved by using methane as a sacrificial fuel. These results demonstrate that noble metals can be successfully paired with zeolites to create a stratified autothermal reactor capable of removing oxygen from biomass model compounds in a compact, continuous flow system that can be configured to have multiple feed inputs, depending on process restrictions. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Utilization of biomass in the U.S. for the production of ethanol fuel as a gasoline replacement. I - Terrestrial resource potential. II - Energy requirements, with emphasis on lignocellulosic conversion

NASA Astrophysics Data System (ADS)

Ferchak, J. D.; Pye, E. K.

The paper assesses the biomass resource represented by starch derived from feed corn, surplus and distressed grain, and high-yield sugar crops planted on set-aside land in the U.S. It is determined that the quantity of ethanol produced may be sufficient to replace between 5 to 27% of present gasoline requirements. Utilization of novel cellulose conversion technology may in addition provide fermentable sugars from municipal, agricultural and forest wastes, and ultimately from highly productive silvicultural operations. The potential additional yield of ethanol from lignocellulosic biomass appears to be well in excess of liquid fuel requirements of an enhanced-efficiency transport sector at present mileage demands. No conflict with food production would be entailed. A net-energy assessment is made for lignocellulosic biomass feedstocks' conversion to ethanol and an almost 10:1 energy yield/energy cost ratio determined. It is also found that novel cellulose pretreatment and enzymatic conversion methods still under development may significantly improve even that figure, and that both chemical-feedstocks and energy-yielding byproducts such as carbon dioxide, biogas and lignin make ethanol production potentially energy self-sufficient. A final high-efficiency production approach incorporates site-optimized, nonpolluting energy sources such as solar and geothermal.

Regional Environmental Impacts of Biofuel Feedstock Production--Scaling Biogeochemical Cycles in Space and Time

NASA Astrophysics Data System (ADS)

Vanloocke, A.; Bernacchi, C.

2008-12-01

Recently there has been increasing socio-economic and scientific interest in the use of alternative sources of energy to offset the negative effects of current fossil fuel dependence and consequent greenhouse gas emissions. Currently, one of the most popular alternatives is to use ethanol produced from domestically grown crops for use as fuel in the transportation sector. In 2007, over 7.5 billion gallons of ethanol were produced in the U.S. from corn, a traditional food crop. Recent research indicates that it may be logistically impractical, ecologically counterproductive (i.e. a net carbon source), and economically devastating to produce ethanol from crops previously grown to produce food. The EBI (Energy Biosciences Institute, at University of California Berkley and University of Illinois Urbana-Champaign) is now conducting research to assess the ability of traditional crops as well as dedicated biofuel feedstocks (e.g. Panicum virgatum (switchgrass), Miscanthus x Giganteus (Miscanthus), and Saccharum spp (sugar cane)) to provide a productive and sustainable alternative to fossil fuel. This is an important step to take before implementing the large-scale growth necessary to meet U.S. energy needs .A process-based terrestrial ecosystem model, Agro-IBIS (Agricultural Integrated Biosphere Simulator) was adapted to simulate the growth of Miscanthus. The model was calibrated using data collected from sites at the University of Illinois south farms. Simulations indicated significant implications on the regional carbon and water budgets. Next this locally validated method will be extrapolated to simulate the regional scale growth of Miscanthus in the Midwestern U.S. and sugarcane in Brazil and a similar analysis will be conducted for switchgrass. The results should provide insight on optimal land-use decisions and legislation that regard meeting energy demands and mitigating climate change in the near future.

New approaches for improving the production of the 1st and 2nd generation ethanol by yeast.

PubMed

Kurylenko, Olena; Semkiv, Marta; Ruchala, Justyna; Hryniv, Orest; Kshanovska, Barbara; Abbas, Charles; Dmytruk, Kostyantyn; Sibirny, Andriy

2016-01-01

Increase in the production of 1st generation ethanol from glucose is possible by the reduction in the production of ethanol co-products, especially biomass. We have developed a method to reduce biomass accumulation of Saccharomyces cerevisiae by the manipulation of the intracellular ATP level due to overexpression of genes of alkaline phosphatase, apyrase or enzymes involved in futile cycles. The strains constructed accumulated up to 10% more ethanol on a cornmeal hydrolysate medium. Similar increase in ethanol accumulation was observed in the mutants resistant to the toxic inhibitors of glycolysis like 3-bromopyruvate and others. Substantial increase in fuel ethanol production will be obtained by the development of new strains of yeasts that ferment sugars of the abundant lignocellulosic feedstocks, especially xylose, a pentose sugar. We have found that xylose can be fermented under elevated temperatures by the thermotolerant yeast, Hansenula polymorpha. We combined protein engineering of the gene coding for xylose reductase (XYL1) along with overexpression of the other two genes responsible for xylose metabolism in yeast (XYL2, XYL3) and the deletion of the global transcriptional activator CAT8, with the selection of mutants defective in utilizing ethanol as a carbon source using the anticancer drug, 3-bromopyruvate. Resulted strains accumulated 20-25 times more ethanol from xylose at the elevated temperature of 45°C with up to 12.5 g L(-1) produced. Increase in ethanol yield and productivity from xylose was also achieved by overexpression of genes coding for the peroxisomal enzymes: transketolase (DAS1) and transaldolase (TAL2), and deletion of the ATG13 gene.

Fermentation Process and Metabolic Flux of Ethanol Production from the Detoxified Hydrolyzate of Cassava Residue

PubMed Central

Li, Xingjiang; Deng, Yongdong; Yang, Ying; Wei, Zhaojun; Cheng, Jieshun; Cao, Lili; Mu, Dongdong; Luo, Shuizhong; Zheng, Zhi; Jiang, Shaotong; Wu, Xuefeng

2017-01-01

With the growth of the world population, energy problems are becoming increasingly severe; therefore, sustainable energy sources have gained enormous importance. With respect to ethanol fuel production, biomass is gradually replacing grain as the main raw material. In this study, we explored the fermentation of five- and six-carbon sugars, the main biomass degradation products, into alcohol. We conducted mutagenic screening specifically for Candida tropicalis CICC1779 to obtain a strain that effectively used xylose (Candida tropicalis CICC1779-Dyd). By subsequently studying fermentation conditions under different initial liquid volume oxygen transfer coefficients (kLα), and coupling control of the aeration rate and agitation speed under optimal conditions, the optimal dissolved oxygen change curve was obtained. In addition, we constructed metabolic flow charts and equations to obtain a better understanding of the fermentation mechanism and to improve the ethanol yield. In our experiment, the ethanol production of the wild type stain was 17.58 g·L−1 at a kLα of 120. The highest ethanol yield of the mutagenic strains was 24.85 g·L−1. The ethanol yield increased to 26.56 g·L−1 when the dissolved oxygen content was optimized, and the conversion of sugar into alcohol reached 0.447 g·g−1 glucose (the theoretical titer of yeast-metabolized xylose was 0.46 g ethanol/g xylose and the glucose ethanol fermentation titer was 0.51 g ethanol/g glucose). Finally, the detected activity of xylose reductase and xylose dehydrogenase was higher in the mutant strain than in the original, which indicated that the mutant strain (CICC1779-Dyd) could effectively utilize xylose for metabolism. PMID:28878755

A new β-glucosidase producing yeast for lower-cost cellulosic ethanol production from xylose-extracted corncob residues by simultaneous saccharification and fermentation.

PubMed

Liu, Z Lewis; Weber, Scott A; Cotta, Michael A; Li, Shi-Zhong

2012-01-01

This study reports a new yeast strain of Clavispora NRRL Y-50464 that is able to utilize cellobiose as sole source of carbon and produce sufficient native β-glucosidase enzyme activity for cellulosic ethanol production using SSF. In addition, this yeast is tolerant to the major inhibitors derived from lignocellulosic biomass pre-treatment such as 2-furaldehyde (furfural) and 5-(hydroxymethyl)-2-furaldehyde (HMF), and converted furfural into furan methanol in less than 12h and HMF into furan-2,5-dimethanol within 24h in the presence of 15 mM each of furfural and HMF. Using xylose-extracted corncob residue as cellulosic feedstock, an ethanol production of 23 g/l was obtained using 25% solids loading at 37 °C by SSF without addition of exogenous β-glucosidase. Development of this yeast aids renewable biofuels development efforts for economic consolidated SSF bio-processing. Published by Elsevier Ltd.

CarbonSAFE Illinois - Macon County

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whittaker, Steve

CarbonSAFE Illinois is a a Feasibility study to develop an established geologic storage complex in Macon County, Illinois, for commercial-scale storage of industrially sourced CO2. Feasibility activities are focused on the Mt. Simon Storage Complex; a step-out well will be drilled near existing storage sites (i.e., the Midwest Geological Sequestration Consortium’s Illinois Basin – Decatur Project and the Illinois Industrial Carbon Capture and Storage Project) to further establish commercial viability of this complex and to evaluate EOR potential in a co-located oil-field trend. The Archer Daniels Midland facility (ethanol plant), City Water, Light, and Power in Springfield, Illinois (coal-fired powermore » station), and other regional industries are potential sources of anthropogenic CO2 for storage at this complex. Site feasibility will be evaluated through drilling results, static and dynamic modeling, and quantitative risk assessment. Both studies will entail stakeholder engagement, consideration of infrastructure requirements, existing policy, and business models. Project data will help calibrate the National Risk Assessment Partnership (NRAP) Toolkit to better understand the risks of commercial-scale carbon storage.« less

Carbon Calculator for Land Use Change from Biofuels Production (CCLUB) Users’ Manual and Technical Documentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunn, Jennifer B.; Qin, Zhangcai; Mueller, Steffen

Themore » $$\\underline{C}$$arbon $$\\underline{C}$$alculator for $$\\underline{L}$$and $$\\underline{U}$$se Change from $$\\underline{B}$$iofuels Production (CCLUB) calculates carbon emissions from land use change (LUC) for four different ethanol production pathways including corn grain ethanol and cellulosic ethanol from corn stover, Miscanthus, and switchgrass. This document discusses the version of CCLUB released September 30, 2014 which includes corn and three cellulosic feedstocks: corn stover, Miscanthus, and switchgrass.« less

Effects of preservatives on stable isotope analyses of four marine species

NASA Astrophysics Data System (ADS)

Carabel, Sirka; Verísimo, Patricia; Freire, Juan

2009-04-01

The aim of the present study is to quantify the effect of formalin-ethanol preservation on the carbon and nitrogen stable isotope signatures of four taxonomical groups of marine species ( Himanthalia elongata, Anemonia sulcata, Mytilus galloprovincialis and Patella vulgata). To examine temporal changes in the effects of preservation and to determine if preservation induced predictable shifts in δ13C and δ15N signatures, repeated analyses were carried out after 6, 12 and 24 months of preservation. Data from our study showed highly variable effects of the formalin-ethanol preservation on carbon and nitrogen isotope signatures between species. The use of a general correction factor was not possible, or else it should be species-specific. Differences in nitrogen isotopic values between preserved and unpreserved samples were minor compared to the assumed enrichment between trophic levels. The combined use of data from preserved and unpreserved samples could lead to biases in the estimation of the trophic level of organisms. Changes that preservatives caused in carbon values were variable between species and not always small enough to be ignored. So the use of data from preserved samples could change the interpretation of the mixing models used to determine the importance of multiple sources of carbon. In order to elucidate the effects that preservatives have in other species, further studies will be necessary.

Microwave plasma chemical synthesis of nanocrystalline carbon film structures and study their properties

NASA Astrophysics Data System (ADS)

Bushuev, N.; Yafarov, R.; Timoshenkov, V.; Orlov, S.; Starykh, D.

2015-08-01

The self-organization effect of diamond nanocrystals in polymer-graphite and carbon films is detected. The carbon materials deposition was carried from ethanol vapors out at low pressure using a highly non-equilibrium microwave plasma. Deposition processes of carbon film structures (diamond, graphite, graphene) is defined. Deposition processes of nanocrystalline structures containing diamond and graphite phases in different volume ratios is identified. The solid film was obtained under different conditions of microwave plasma chemical synthesis. We investigated the electrical properties of the nanocrystalline carbon films and identified it's from various factors. Influence of diamond-graphite film deposition mode in non-equilibrium microwave plasma at low pressure on emission characteristics was established. This effect is justified using the cluster model of the structure of amorphous carbon. It was shown that the reduction of bound hydrogen in carbon structures leads to a decrease in the threshold electric field of emission from 20-30 V/m to 5 V/m. Reducing the operating voltage field emission can improve mechanical stability of the synthesized film diamond-graphite emitters. Current density emission at least 20 A/cm2 was obtained. Nanocrystalline carbon film materials can be used to create a variety of functional elements in micro- and nanoelectronics and photonics such as cold electron source for emission in vacuum devices, photonic devices, cathodoluminescent flat display, highly efficient white light sources. The obtained graphene carbon net structure (with a net size about 6 μm) may be used for the manufacture of large-area transparent electrode for solar cells and cathodoluminescent light sources

Dynamic response of tapered optical multimode fiber coated with carbon nanotubes for ethanol sensing application.

PubMed

Shabaneh, Arafat; Girei, Saad; Arasu, Punitha; Mahdi, Mohd; Rashid, Suraya; Paiman, Suriati; Yaacob, Mohd

2015-05-04

Ethanol is a highly combustible chemical universally designed for biomedical applications. In this paper, optical sensing performance of tapered multimode fiber tip coated with carbon nanotube (CNT) thin film towards aqueous ethanol with different concentrations is investigated. The tapered optical multimode fiber tip is coated with CNT using drop-casting technique and is annealed at 70 °C to enhance the binding of the nanomaterial to the silica fiber tip. The optical fiber tip and the CNT sensing layer are micro-characterized using FESEM and Raman spectroscopy techniques. When the developed sensor was exposed to different concentrations of ethanol (5% to 80%), the sensor reflectance reduced proportionally. The developed sensors showed high sensitivity, repeatability and fast responses (<55 s) towards ethanol.

Dynamic Response of Tapered Optical Multimode Fiber Coated with Carbon Nanotubes for Ethanol Sensing Application

PubMed Central

Shabaneh, Arafat; Girei, Saad; Arasu, Punitha; Mahdi, Mohd; Rashid, Suraya; Paiman, Suriati; Yaacob, Mohd

2015-01-01

Ethanol is a highly combustible chemical universally designed for biomedical applications. In this paper, optical sensing performance of tapered multimode fiber tip coated with carbon nanotube (CNT) thin film towards aqueous ethanol with different concentrations is investigated. The tapered optical multimode fiber tip is coated with CNT using drop-casting technique and is annealed at 70 °C to enhance the binding of the nanomaterial to the silica fiber tip. The optical fiber tip and the CNT sensing layer are micro-characterized using FESEM and Raman spectroscopy techniques. When the developed sensor was exposed to different concentrations of ethanol (5% to 80%), the sensor reflectance reduced proportionally. The developed sensors showed high sensitivity, repeatability and fast responses (<55 s) towards ethanol. PMID:25946634

Enzyme-free ethanol sensor based on electrospun nickel nanoparticle-loaded carbon fiber paste electrode.

PubMed

Liu, Yang; Zhang, Lei; Guo, Qiaohui; Hou, Haoqing; You, Tianyan

2010-03-24

We have developed a novel nickel nanoparticle-loaded carbon fiber paste (NiCFP) electrode for enzyme-free determination of ethanol. An electrospinning technique was used to prepare the NiCF composite with large amounts of spherical nanoparticles firmly embedded in carbon fibers (CF). In application to electroanalysis of ethanol, the NiCFP electrode exhibited high amperometric response and good operational stability. The calibration curve was linear up to 87.5 mM with a detection limit of 0.25 mM, which is superior to that obtained with other transition metal based electrodes. For detection of ethanol present in liquor samples, the values obtained with the NiCFP electrode were in agreement with the ones declared on the label. The attractive analytical performance and simple preparation method make this novel material promising for the development of effective enzyme-free sensors. Copyright 2010 Elsevier B.V. All rights reserved.

Performance of carbon nanofiber supported Pd-Ni catalysts for electro-oxidation of ethanol in alkaline medium

NASA Astrophysics Data System (ADS)

Maiyalagan, T.; Scott, Keith

Carbon nanofibers (CNF) supported Pd-Ni nanoparticles have been prepared by chemical reduction with NaBH 4 as a reducing agent. The Pd-Ni/CNF catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical voltammetry analysis. TEM showed that the Pd-Ni particles were quite uniformly distributed on the surface of the carbon nanofiber with an average particle size of 4.0 nm. The electro-catalytic activity of the Pd-Ni/CNF for oxidation of ethanol was examined by cyclic voltammetry (CV). The onset potential was 200 mV lower and the peak current density four times higher for ethanol oxidation for Pd-Ni/CNF compared to that for Pd/C. The effect of an increase in temperature from 20 to 60 °C had a great effect on increasing the ethanol oxidation activity.

Supercritical carbon dioxide-based sterilization of decellularized heart valves.

PubMed

Hennessy, Ryan S; Jana, Soumen; Tefft, Brandon J; Helder, Meghana R; Young, Melissa D; Hennessy, Rebecca R; Stoyles, Nicholas J; Lerman, Amir

2017-02-01

The goal of this research project encompasses finding the most efficient and effective method of decellularized tissue sterilization. Aortic tissue grafts have been utilized to repair damaged or diseased valves. Although, the tissues for grafting are collected aseptically, it does not eradicate the risk of contamination nor disease transfer. Thus, sterilization of grafts is mandatory. Several techniques have been applied to sterilize grafts; however, each technique shows drawbacks. In this study, we compared several sterilization techniques: supercritical carbon dioxide, electrolyzed water, gamma radiation, ethanol-peracetic acid, and hydrogen peroxide for impact on the sterility and mechanical integrity of porcine decellularized aortic valves. Valve sterility was characterized by histology, microbe culture, and electron microscopy. Uniaxial tensile testing was conducted on the valve cusps along their circumferential orientation to study these sterilization techniques on their integrity. Ethanol-peracetic acid and supercritical carbon dioxide treated valves were found to be sterile. The tensile strength of supercritical carbon dioxide treated valves (4.28 ± 0.22 MPa) was higher to those valves treated with electrolyzed water, gamma radiation, ethanol-peracetic acid and hydrogen peroxide (1.02 ± 0.15, 1.25 ± 0.25, 3.53 ± 0.41 and 0.37 ± 0.04 MPa, respectively). Superior sterility and integrity were found in the decellularized porcine aortic valves with supercritical carbon dioxide sterilization. This sterilization technique may hold promise for other decellularized soft tissues. Sterilization of grafts is essential. Supercritical carbon dioxide, electrolyzed water, gamma radiation, ethanol-peracetic acid, and hydrogen peroxide techniques were compared for impact on sterility and mechanical integrity of porcine decellularized aortic valves. Ethanol-peracetic acid and supercritical carbon dioxide treated valves were found to be sterile using histology, microbe culture and electron microscopy assays. The cusp tensile properties of supercritical carbon dioxide treated valves were higher compared to valves treated with other techniques. Superior sterility and integrity was found in the decellularized valves treated with supercritical carbon dioxide sterilization. This sterilization technique may hold promise for other decellularized soft tissues.

New insights to the use of ethanol in automotive fuels: a stable isotopic tracer for fossil- and bio-fuel combustion inputs to the atmosphere.

PubMed

Giebel, Brian M; Swart, Peter K; Riemer, Daniel D

2011-08-01

Ethanol is currently receiving increased attention because of its use as a biofuel or fuel additive and because of its influence on air quality. We used stable isotopic ratio measurements of (13)C/(12)C in ethanol emitted from vehicles and a small group of tropical plants to establish ethanol's δ(13)C end-member signatures. Ethanol emitted in exhaust is distinctly different from that emitted by tropical plants and can serve as a unique stable isotopic tracer for transportation-related inputs to the atmosphere. Ethanol's unique isotopic signature in fuel is related to corn, a C4 plant and the primary source of ethanol in the U.S. We estimated a kinetic isotope effect (KIE) for ethanol's oxidative loss in the atmosphere and used previous assumptions with respect to the fractionation that may occur during wet and dry deposition. A small number of interpretive model calculations were used for source apportionment of ethanol and to understand the associated effects resulting from atmospheric removal. The models incorporated our end-member signatures and ambient measurements of ethanol, known or estimated source strengths and removal magnitudes, and estimated KIEs associated with atmospheric removal processes for ethanol. We compared transportation-related ethanol signatures to those from biogenic sources and used a set of ambient measurements to apportion each source contribution in Miami, Florida-a moderately polluted, but well ventilated urban location.

Developing Biofuel in the Teaching Laboratory: Ethanol from Various Sources

ERIC Educational Resources Information Center

Epstein, Jessica L.; Vieira, Matthew; Aryal, Binod; Vera, Nicolas; Solis, Melissa

2010-01-01

In this series of experiments, we mimic a small-scale ethanol plant. Students discover that the practical aspects of ethanol production are determined by the quantity of biomass produced per unit land, rather than the volume of ethanol produced per unit of biomass. These experiments explore the production of ethanol from different sources: fruits,…

Effect of Ethanol Chemistry on SCC of Carbon Steel

DOT National Transportation Integrated Search

2011-02-22

Pipeline companies have a keen interest in assessing the feasibility of transporting fuel grade ethanol (FGE) and ethanol blends in existing pipelines. Previous field experience and laboratory research, funded by PRCI and API, has shown that steel ca...

Methanol production method and system

DOEpatents

Chen, Michael J.; Rathke, Jerome W.

1984-01-01

Ethanol is selectively produced from the reaction of methanol with carbon monoxide and hydrogen in the presence of a transition metal carbonyl catalyst. Methanol serves as a solvent and may be accompanied by a less volatile co-solvent. The solution includes the transition metal carbonyl catalysts and a basic metal salt such as an alkali metal or alkaline earth metal formate, carbonate or bicarbonate. A gas containing a high carbon monoxide to hydrogen ratio, as is present in a typical gasifer product, is contacted with the solution for the preferential production of ethanol with minimal water as a byproduct. Fractionation of the reaction solution provides substantially pure ethanol product and allows return of the catalysts for reuse.

Detoxification of Eucheuma spinosum Hydrolysates with Activated Carbon for Ethanol Production by the Salt-Tolerant Yeast Candida tropicalis.

PubMed

Ra, Chae Hun; Jung, Jang Hyun; Sunwoo, In Young; Kang, Chang Han; Jeong, Gwi-Taek; Kim, Sung-Koo

2015-06-01

The objective of this study was to optimize the slurry contents and salt concentrations for ethanol production from hydrolysates of the seaweed Eucheuma spinosum. A monosaccharide concentration of 44.2 g/l as 49.6% conversion of total carbohydrate of 89.1 g/l was obtained from 120 g dw/l seaweed slurry. Monosaccharides from E. spinosum slurry were obtained by thermal acid hydrolysis and enzymatic hydrolysis. Addition of activated carbon at 2.5% (w/v) and the adsorption time of 2 min were used in subsequent adsorption treatments to prevent the inhibitory effect of HMF. The adsorption surface area of the activated carbon powder was 1,400-1,600 m(2)/g and showed selectivity to 5-hydroxymethyl furfural (HMF) from monosaccharides. Candida tropicalis KCTC 7212 was cultured in yeast extract, peptone, glucose, and high-salt medium, and exposed to 80, 90, 100, and 110 practical salinity unit (psu) salt concentrations in the lysates. The 100 psu salt concentration showed maximum cell growth and ethanol production. The ethanol fermentations with activated carbon treatment and use of C. tropicalis acclimated to a high salt concentration of 100 psu produced 17.9 g/l of ethanol with a yield (YEtOH) of 0.40 from E. spinosum seaweed.

Novel Strategies for the Production of Fuels, Lubricants, and Chemicals from Biomass.

PubMed

Shylesh, Sankaranarayanapillai; Gokhale, Amit A; Ho, Christopher R; Bell, Alexis T

2017-10-17

Growing concern with the environmental impact of CO 2 emissions produced by combustion of fuels derived from fossil-based carbon resources has stimulated the search for renewable sources of carbon. Much of this focus has been on the development of methods for producing transportation fuels, the major source of CO 2 emissions today, and to a lesser extent on the production of lubricants and chemicals. First-generation biofuels such as bioethanol, produced by the fermentation of sugar cane- or corn-based sugars, and biodiesel, produced by the transesterification reaction of triglycerides with alcohols to form a mixture of long-chain fatty esters, can be blended with traditional fuels in limited amounts and also arise in food versus fuel debates. Producing molecules that can be drop-in solutions for fossil-derived products used in the transportation sector allows for efficient use of the existing infrastructure and is therefore particularly interesting. In this context, the most viable source of renewable carbon is abundantly available lignocellulosic biomass, a complex mixture of lignin, hemicellulose, and cellulose. Conversion of the carbohydrate portion of biomass (hemicellulose and cellulose) to fuels requires considerable chemical restructuring of the component sugars in order to achieve the energy density and combustion properties required for transportation fuels-gasoline, diesel, and jet. A different set of constraints must be met for the conversion of biomass-sourced sugars to lubricants and chemicals. This Account describes strategies developed by us to utilize aldehydes, ketones, alcohols, furfurals, and carboxylic acids derived from C 5 and C 6 sugars, acetone-butanol-ethanol (ABE) fermentation mixtures, and various biomass-derived carboxylic acids and fatty acids to produce fuels, lubricants, and chemicals. Oxygen removal from these synthons is achieved by dehydration, decarboxylation, hydrogenolysis, and hydrodeoxygenation, whereas reactions such as aldol condensation, etherification, alkylation, and ketonization are used to build up the number of carbon atoms in the final product. We show that our strategies lead to high-octane components that can be blended into gasoline, C 9 -C 22 compounds that possess energy densities and properties required for diesel and jet fuels, and lubricants that are equivalent or superior to current synthetic lubricants. Replacing a fraction of the crude-oil-derived products with such renewable sources can mitigate the negative impact of the transportation sector on overall anthropogenic greenhouse gas (GHG) emissions and climate change potential. While ethanol is a well-known fuel additive, there is significant interest in using ethanol as a platform molecule to manufacture a variety of valuable chemicals. We show that bioethanol can be converted with high selectivity to butanol or 1,3-butadiene, providing interesting alternatives to the current production from petroleum. Finally, we report that several of the strategies developed have the potential to reduce GHG emissions by 55-80% relative to those for petroleum-based processes.

Microbial Community Changes in Response to Ethanol or Methanol Amendments for U(VI) Reduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vishnivetskaya, Tatiana A; Brandt, Craig C; Madden, Andrew

2010-01-01

Microbial community responses to ethanol, methanol and methanol + humics amendments in relationship to uranium bioremediation were studied in laboratory microcosm experiments using sediments and ground water from a uranium-contaminated site in Oak Ridge, Tennessee. Ethanol addition always resulted in uranium reduction at rate of 0.8-1.0 mol l-1 d-1 while methanol addition did so occasionally at rate 0.95 mol l-1 d-1. The type of carbon source added, the duration of incubation, and the sampling site influenced the bacterial community structure upon incubation. Analysis of 16S rRNA gene clone libraries indicated (1) bacterial communities found in ethanol- and methanol-amended samples withmore » U(VI) reduction were similar due to presence of -Proteobacteria, and -Proteobacteria (members of the families Burkholderiaceae, Comamonadaceae, Oxalobacteraceae, and Rhodocyclaceae); (2) methanol-amended samples without U(VI) reduction exhibited the lowest diversity and the bacterial community contained 69.2-92.8% of the family Methylophilaceae; and (3) the addition of humics resulted in an increase of phylogenetic diversity of -Proteobacteria (Rodoferax, Polaromonas, Janthinobacterium, Methylophilales, unclassified) and Firmicutes (Desulfosporosinus, Clostridium).« less

Co-fermentation of carbon sources by Enterobacter aerogenes ATCC 29007 to enhance the production of bioethanol.

PubMed

Thapa, Laxmi Prasad; Lee, Sang Jun; Yang, Xiao Guang; Yoo, Hah Young; Kim, Sung Bong; Park, Chulhwan; Kim, Seung Wook

2014-06-01

We investigated the enhancement of bioethanol production in Enterobacter aerogenes ATCC 29007 by co-fermentation of carbon sources such as glycerol, glucose, galactose, sucrose, fructose, xylose, starch, mannitol and citric acid. Biofuel production increases with increasing growth rate of microorganisms; that is why we investigated the optimal growth rate of E. aerogenes ATCC 29007, using mixtures of different carbon sources with glycerol. E. aerogenes ATCC 29007 was incubated in media containing each carbon source and glycerol; growth rate and bioethanol production improved in all cases compared to those in medium containing glycerol alone. The growth rate and bioethanol production were highest with mannitol. Fermentation was carried out at 37 °C for 18 h, pH 7, using 50 mL defined production medium in 100 mL serum bottles at 200 rpm. Bioethanol production under optimized conditions in medium containing 16 g/L mannitol and 20 g/L glycerol increased sixfold (32.10 g/L) than that containing glycerol alone (5.23 g/L) as the carbon source in anaerobic conditions. Similarly, bioethanol production using free cells in continuous co-fermentation also improved (27.28 g/L) when 90.37 % of 16 g/L mannitol and 67.15 % of 20 g/L glycerol were used. Although naturally existing or engineered microorganisms can ferment mixed sugars sequentially, the preferential utilization of glucose to non-glucose sugars often results in lower overall yield and productivity of ethanol. Here, we present new findings in E. aerogenes ATCC 29007 that can be used to improve bioethanol production by simultaneous co-fermentation of glycerol and mannitol.

Removal of Atmospheric Ethanol by Wet Deposition: A Global Flux Estimate

NASA Astrophysics Data System (ADS)

Felix, J. D. D.; Willey, J. D.; Avery, B.; Thomas, R.; Mullaugh, K.; Kieber, R. J.; Mead, R. N.; Helms, J. R.; Campos, L.; Shimizu, M. S.; Guibbina, F.

2017-12-01

Global ethanol fuel consumption has increased exponentially over the last two decades and the US plans to double annual renewable fuel production in the next five years as required by the renewable fuel standard. Regardless of the technology or feedstock used to produce the renewable fuel, the primary end product will be ethanol. Increasing ethanol fuel consumption will have an impact on the oxidizing capacity of the atmosphere and increase atmospheric concentrations of the secondary pollutant peroxyacetyl nitrate as well a variety of VOCs with relatively high ozone reactivities (e.g. ethanol, formaldehyde, acetaldehyde). Despite these documented effects of ethanol emissions on atmospheric chemistry, current global atmospheric ethanol budget models have large uncertainties in the magnitude of ethanol sources and sinks. The presented work investigates the global wet deposition sink by providing the first estimate of the global wet deposition flux of ethanol (2.4 ± 1.6 Tg/yr) based on empirical wet deposition data (219 samples collected at 12 locations). This suggests the wet deposition sink removes between 6 and 17% of atmospheric ethanol annually. Concentrations of ethanol in marine wet deposition (25 ± 6 nM) were an order of magnitude less than in the majority of terrestrial deposition (345 ± 280 nM). Terrestrial deposition collected in locations impacted by high local sources of biofuel usage and locations downwind from ethanol distilleries were an order of magnitude higher in ethanol concentration (3090 ± 448 nM) compared to deposition collected in terrestrial locations not impacted by these sources. These results indicate that wet deposition of ethanol is heavily influenced by local sources and ethanol emission impacts on air quality may be more significant in highly populated areas. As established and developing countries continue to rapidly increase ethanol fuel consumption and subsequent emissions, understanding the magnitude of all ethanol sources and sinks and impacts on the atmosphere is essential.

Transcriptional regulation of the protein kinase a subunits in Saccharomyces cerevisiae during fermentative growth.

PubMed

Galello, Fiorella; Pautasso, Constanza; Reca, Sol; Cañonero, Luciana; Portela, Paula; Moreno, Silvia; Rossi, Silvia

2017-12-01

Yeast cells can adapt their growth in response to the nutritional environment. Glucose is the favourite carbon source of Saccharomyces cerevisiae, which prefers a fermentative metabolism despite the presence of oxygen. When glucose is consumed, the cell switches to the aerobic metabolism of ethanol, during the so-called diauxic shift. The difference between fermentative and aerobic growth is in part mediated by a regulatory mechanism called glucose repression. During glucose derepression a profound gene transcriptional reprogramming occurs and genes involved in the utilization of alternative carbon sources are expressed. Protein kinase A (PKA) controls different physiological responses following the increment of cAMP as a consequence of a particular stimulus. cAMP-PKA is one of the major pathways involved in the transduction of glucose signalling. In this work the regulation of the promoters of the PKA subunits during respiratory and fermentative metabolism are studied. It is demonstrated that all these promoters are upregulated in the presence of glycerol as carbon source through the Snf1/Cat8 pathway. However, in the presence of glucose as carbon source, the regulation of each PKA promoter subunits is different and only TPK1 is repressed by the complex Hxk2/Mig1 in the presence of active Snf1. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Engineering microorganisms to increase ethanol production by metabolic redirection

DOEpatents

Deng, Yu; Olson, Daniel G.; van Dijken, Johannes Pieter; Shaw, IV, Arthur J.; Argyros, Aaron; Barrett, Trisha; Caiazza, Nicky; Herring, Christopher D.; Rogers, Stephen R.; Agbogbo, Frank

2017-10-31

The present invention provides for the manipulation of carbon flux in a recombinant host cell to increase the formation of desirable products. The invention relates to cellulose-digesting organisms that have been genetically modified to allow the production of ethanol at a high yield by redirecting carbon flux at key steps of central metabolism.

Pentoses and light intensity increase the growth and carbohydrate production and alter the protein profile of Chlorella minutissima.

PubMed

Freitas, B C B; Cassuriaga, A P A; Morais, M G; Costa, J A V

2017-08-01

High concentrations of carbon, which is considered a necessary element, are required for microalgal growth. Therefore, the identification of alternative carbon sources available in large quantities is increasingly important. This study evaluated the effects of light variation and pentose addition on the carbohydrate content and protein profile of Chlorella minutissima grown in a raceway photobioreactor. The kinetic parameters, carbohydrate content, and protein profile of Chlorella minutissima and its theoretical potential for ethanol production were estimated. The highest cellular concentrations were obtained with a light intensity of 33.75µmol.m -2 .s -1 . Arabinose addition combined with a light intensity of 33.75µmol.m -2 .s -1 increased the carbohydrate content by 53.8% and theoretically produced 39.1mL·100g -1 ethanol. All of the assays showed that a lower light availability altered the protein profile. The luminous intensity affects xylose and arabinose assimilation and augments the carbohydrate content in C. minutissima, making this microalga appropriate for bioethanol production. Copyright © 2017 Elsevier Ltd. All rights reserved.

A portable gas sensor based on cataluminescence.

PubMed

Kang, C; Tang, F; Liu, Y; Wu, Y; Wang, X

2013-01-01

We describe a portable gas sensor based on cataluminescence. Miniaturization of the gas sensor was achieved by using a miniature photomultiplier tube, a miniature gas pump and a simple light seal. The signal to noise ratio (SNR) was considered as the evaluation criteria for the design and testing of the sensor. The main source of noise was from thermal background. Optimal working temperature and flow rate were determined experimentally from the viewpoint of improvement in SNR. A series of parameters related to analytical performance was estimated. The limitation of detection of the sensor was 7 ppm (SNR = 3) for ethanol and 10 ppm (SNR = 3) for hydrogen sulphide. Zirconia and barium carbonate were respectively selected as nano-sized catalysts for ethanol and hydrogen sulphide. Copyright © 2012 John Wiley & Sons, Ltd.

Scalable graphene production from ethanol decomposition by microwave argon plasma torch

NASA Astrophysics Data System (ADS)

Melero, C.; Rincón, R.; Muñoz, J.; Zhang, G.; Sun, S.; Perez, A.; Royuela, O.; González-Gago, C.; Calzada, M. D.

2018-01-01

A fast, efficient and simple method is presented for the production of high quality graphene on a large scale by using an atmospheric pressure plasma-based technique. This technique allows to obtain high quality graphene in powder in just one step, without the use of neither metal catalysts and nor specific substrate during the process. Moreover, the cost for graphene production is significantly reduced since the ethanol used as carbon source can be obtained from the fermentation of agricultural industries. The process provides an additional benefit contributing to the revalorization of waste in the production of a high-value added product like graphene. Thus, this work demonstrates the features of plasma technology as a low cost, efficient, clean and environmentally friendly route for production of high-quality graphene.

Effects of zinc on the production of alcohol by Clostridium carboxidivorans P7 using model syngas.

PubMed

Li, Demao; Meng, Chunxiao; Wu, Guanxun; Xie, Bintao; Han, Yifan; Guo, Yaqiong; Song, Chunhui; Gao, Zhengquan; Huang, Zhiyong

2018-01-01

Renewable energy, including biofuels such as ethanol and butanol from syngas bioconversed by Clostridium carboxidivorans P7, has been drawing extensive attention due to the fossil energy depletion and global eco-environmental issues. Effects of zinc on the growth and metabolites of C. carboxidivorans P7 were investigated with model syngas as the carbon source. The cell concentration was doubled, the ethanol content increased 3.02-fold and the butanol content increased 7.60-fold, the hexanol content increased 44.00-fold in the medium with 280 μM Zn 2+ , when comparing with those in the control medium [Zn 2+ , (7 μM)]. Studies of the genes expression involved in the carbon fixation as well as acid and alcohol production in the medium with 280 μM Zn 2+ indicated that fdhII was up-regulated on the second day, acs A, fdhII, bdh35 and bdh50 were up-regulated on the third day and bdh35, acsB, fdhI, fdhIII, fdhIV, buk, bdh10, bdh35, bdh40 and bdh50 were up-regulated on the fourth day. The results indicated that the increased Zn 2+ content increased the alcohol production through increase in the gene expression of the carbon fixation and alcohol dehydrogenase.

Denatured ethanol release into gasoline residuals, Part 1: source behaviour.

PubMed

Freitas, Juliana G; Barker, James F

2013-05-01

With the increasing use of ethanol in fuels, it is important to evaluate its fate when released into the environment. While ethanol is less toxic than other organic compounds present in fuels, one of the concerns is the impact ethanol might have on the fate of gasoline hydrocarbons in groundwater. One possible concern is the spill of denatured ethanol (E95: ethanol containing 5% denaturants, usually hydrocarbons) in sites with pre-existing gasoline contamination. In that scenario, ethanol is expected to increase the mobility of the NAPL phase by acting as a cosolvent and decreasing interfacial tension. To evaluate the E95 behaviour and its impacts on pre-existing gasoline, a field test was performed at the CFB-Borden aquifer. Initially gasoline contamination was created releasing 200 L of E10 (gasoline with 10% ethanol) into the unsaturated zone. One year later, 184 L of E95 was released on top of the gasoline contamination. The site was monitored using soil cores, multilevel wells and one glass access tube. At the end of the test, the source zone was excavated and the compounds remaining were quantified. E95 ethanol accumulated and remained within the capillary fringe and unsaturated zone for more than 200 days, despite ~1m oscillations in the water table. The gasoline mobility increased and it was redistributed in the source zone. Gasoline NAPL saturations in the soil increased two fold in the source zone. However, water table oscillations caused a separation between the NAPL and ethanol: NAPL was smeared and remained in deeper positions while ethanol moved upwards following the water table rise. Similarly, the E95 denaturants that initially were within the ethanol-rich phase became separated from ethanol after the water table oscillation, remaining below the ethanol rich zone. The separation between ethanol and hydrocarbons in the source after water table oscillation indicates that ethanol's impact on hydrocarbon residuals is likely limited to early times. Copyright © 2013 Elsevier B.V. All rights reserved.

Microbial communities biostimulated by ethanol during uranium (VI) bioremediation in contaminated sediment as shown by stable isotope probing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leigh, Mary Beth; Wu, Wei -Min; Cardenas, Erick

Stable isotope probing (SIP) was used to identify microbes stimulated by ethanol addition in microcosms containing two sediments collected from the bioremediation test zone at the US Department of Energy Oak Ridge site, TN, USA. One sample was highly bioreduced with ethanol while another was less reduced. Microcosms with the respective sediments were amended with 13C labeled ethanol and incubated for 7 days for SIP. Ethanol was rapidly converted to acetate within 24 h accompanied with the reduction of nitrate and sulfate. The accumulation of acetate persisted beyond the 7 d period. Aqueous U did not decline in the microcosmmore » with the reduced sediment due to desorption of U but continuously declined in the less reduced sample. Microbial growth and concomitant 13C-DNA production was detected when ethanol was exhausted and abundant acetate had accumulated in both microcosms. This coincided with U(VI) reduction in the less reduced sample. 13C originating from ethanol was ultimately utilized for growth, either directly or indirectly, by the dominant microbial community members within 7 days of incubation. The microbial community was comprised predominantly of known denitrifiers, sulfate-reducing bacteria and iron (III) reducing bacteria including Desulfovibrio, Sphingomonas, Ferribacterium, Rhodanobacter, Geothrix, Thiobacillus and others, including the known U(VI)-reducing bacteria Acidovorax, Anaeromyxobacter, Desulfovibrio, Geobacter and Desulfosporosinus. As a result, the findings suggest that ethanol biostimulates the U(VI)-reducing microbial community by first serving as an electron donor for nitrate, sulfate, iron (III) and U(VI) reduction, and acetate which then functions as electron donor for U(VI) reduction and carbon source for microbial growth.« less

Enhanced isoprenoid production from xylose by engineered Saccharomyces cerevisiae.

PubMed

Kwak, Suryang; Kim, Soo Rin; Xu, Haiqing; Zhang, Guo-Chang; Lane, Stephan; Kim, Heejin; Jin, Yong-Su

2017-11-01

Saccharomyces cerevisiae has limited capabilities for producing fuels and chemicals derived from acetyl-CoA, such as isoprenoids, due to a rigid flux partition toward ethanol during glucose metabolism. Despite numerous efforts, xylose fermentation by engineered yeast harboring heterologous xylose metabolic pathways was not as efficient as glucose fermentation for producing ethanol. Therefore, we hypothesized that xylose metabolism by engineered yeast might be a better fit for producing non-ethanol metabolites. We indeed found that engineered S. cerevisiae on xylose showed higher expression levels of the enzymes involved in ethanol assimilation and cytosolic acetyl-CoA synthesis than on glucose. When genetic perturbations necessary for overproducing squalene and amorphadiene were introduced into engineered S. cerevisiae capable of fermenting xylose, we observed higher titers and yields of isoprenoids under xylose than glucose conditions. Specifically, co-overexpression of a truncated HMG1 (tHMG1) and ERG10 led to substantially higher squalene accumulation under xylose than glucose conditions. In contrast to glucose utilization producing massive amounts of ethanol regardless of aeration, xylose utilization allowed much less amounts of ethanol accumulation, indicating ethanol is simultaneously re-assimilated with xylose consumption and utilized for the biosynthesis of cytosolic acetyl-CoA. In addition, xylose utilization by engineered yeast with overexpression of tHMG1, ERG10, and ADS coding for amorphadiene synthase, and the down-regulation of ERG9 resulted in enhanced amorphadiene production as compared to glucose utilization. These results suggest that the problem of the rigid flux partition toward ethanol production in yeast during the production of isoprenoids and other acetyl-CoA derived chemicals can be bypassed by using xylose instead of glucose as a carbon source. Biotechnol. Bioeng. 2017;114: 2581-2591. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Optimization of carbon and nitrogen medium components for biomass production using non-Saccharomyces wine yeasts.

PubMed

Schnierda, T; Bauer, F F; Divol, B; van Rensburg, E; Görgens, J F

2014-05-01

The impact of different nitrogen and carbon sources on biomass production of the non-Saccharomyces wine yeast species Lachancea thermotolerans, Metschnikowia pulcherrima and Issatchenkia orientalis was assessed. Using a molasses-based medium, yeast extract and corn steep liquor as well as ammonium sulphate and di-ammonium phosphate (DAP) as nitrogen sources were compared in shake-flask cultures. A medium with 20 g l⁻¹ sugar (diluted molasses) and 500 mg l⁻¹ total yeast assimilable nitrogen, from yeast extract, gave the highest biomass concentrations and yields. Invertase pretreatment was required for cultures of M. pulcherrima and I. orientalis, and respective biomass yields of 0.7 and 0.8 g g⁻¹ were achieved in aerobic bioreactor cultures. The absence of ethanol production suggested Crabtree-negative behaviour by these yeasts, whereas Crabtree-positive behaviour by L. thermotolerans resulted in ethanol and biomass concentrations of 5.5 and 11.1 g l⁻¹, respectively. Recent studies demonstrate that non-Saccharomyces yeasts confer positive attributes to the final composition of wine. However, optimal process conditions for their biomass production have not been described, thereby limiting commercial application. In this study, industrial media and methods of yeast cultivation were investigated to develop protocols for biomass production of non-Saccharomyces yeast starter cultures for the wine industry. © 2014 The Society for Applied Microbiology.

Comparative assessment of synthetic strategies toward active platinum-rhodium-tin electrocatalysts for efficient ethanol electro-oxidation

NASA Astrophysics Data System (ADS)

Erini, Nina; Krause, Paul; Gliech, Manuel; Yang, Ruizhi; Huang, Yunhui; Strasser, Peter

2015-10-01

The present work explores the effect of autoclave-based autogenous-pressure vs. ambient pressure conditions on the synthesis and properties of carbon-supported Pt-Rh-Sn nanoparticle electrocatalysts. The Pt-Rh-Sn nanoparticles were characterized by X-ray spectroscopy, electron microscopy and mass spectroscopy and deployed as catalysts for the electrocatalytic ethanol oxidation reaction. Pt-Rh-Sn catalysts precipitated with carbon already present showed narrow particle size distribution around 7 nm, while catalysts supported on carbon after particle formation showed broader size distribution ranging from 8 to 16 nm, similar metal loadings between 40 and 48 wt.% and similar atomic ratios of Pt:Rh:Sn of 30:10:60. The highest ethanol oxidation activity at low overpotentials associated with exceptionally early ethanol oxidation onset potential was observed for ambient-pressure catalysts with the active ternary alloy phase formed in presence of the carbon supports. In contrast, catalysts prepared under ambient pressure in a two-step approach, involving alloy particle formation followed by particle separation and subsequent deposition on the carbon support, yielded the highest overall mass activities. Based on the observed synthesis-activity correlations, a comparative assessment is provided of the synthetic techniques at high vs. low pressures, and in presence and absence of carbon support. Plausible hypotheses in terms of particle dispersion and interparticle distance accounting for these observed differences are discussed.

Designer organisms for photosynthetic production of ethanol from carbon dioxide and water

DOEpatents

Lee, James Weifu [Knoxville, TN

2011-07-05

The present invention provides a revolutionary photosynthetic ethanol production technology based on designer transgenic plants, algae, or plant cells. The designer plants, designer algae, and designer plant cells are created such that the endogenous photosynthesis regulation mechanism is tamed, and the reducing power (NADPH) and energy (ATP) acquired from the photosynthetic water splitting and proton gradient-coupled electron transport process are used for immediate synthesis of ethanol (CH.sub.3CH.sub.2OH) directly from carbon dioxide (CO.sub.2) and water (H.sub.2O). The ethanol production methods of the present invention completely eliminate the problem of recalcitrant lignocellulosics by bypassing the bottleneck problem of the biomass technology. The photosynthetic ethanol-production technology of the present invention is expected to have a much higher solar-to-ethanol energy-conversion efficiency than the current technology and could also help protect the Earth's environment from the dangerous accumulation of CO.sub.2 in the atmosphere.

Life cycle evaluation of emerging lignocellulosic ethanol conversion technologies.

PubMed

Spatari, Sabrina; Bagley, David M; MacLean, Heather L

2010-01-01

Lignocellulosic ethanol holds promise for addressing climate change and energy security issues associated with personal transportation through lowering the fuel mixes' carbon intensity and petroleum demand. We compare the technological features and life cycle environmental impacts of near- and mid-term ethanol bioconversion technologies in the United States. Key uncertainties in the major processes: pre-treatment, hydrolysis, and fermentation are evaluated. The potential to reduce fossil energy use and greenhouse gas (GHG) emissions varies among bioconversion processes, although all options studied are considerably more attractive than gasoline. Anticipated future performance is found to be considerably more attractive than that published in the literature as being achieved to date. Electricity co-product credits are important in characterizing the GHG impacts of different ethanol production pathways; however, in the absence of near-term liquid transportation fuel alternatives to gasoline, optimizing ethanol facilities to produce ethanol (as opposed to co-products) is important for reducing the carbon intensity of the road transportation sector and for energy security.

A comparative study on composition and antioxidant activities of supercritical carbon dioxide, hexane and ethanol extracts from blackberry (Rubus fruticosus) growing in Poland.

PubMed

Wajs-Bonikowska, Anna; Stobiecka, Agnieszka; Bonikowski, Radosław; Krajewska, Agnieszka; Sikora, Magdalena; Kula, Józef

2017-08-01

Large quantities of blackberry seeds are produced as a pomace during the processing of juice and jam production; this by-product is a very interesting raw material both for oil manufacturing and as a source of bioactive compounds. In this work the composition, yield and antioxidant activity of three types of Rubus fructicosus pomace extracts isolated by liquid extraction using solvents of different polarity, as well with supercritical CO 2 fluid extraction have been compared. The highest extract yield was reported for Soxhlet extraction using ethanol as a solvent (14.2%). Supercritical carbon dioxide and hexane extracts were characterised by the highest content of phytosterols (1445 and 1583 mg 100 g -1 of extract, respectively) among which β-sitosterol was the main one, while the concentration of tocopherols, with predominant γ-isomer, was the highest for both hexane and ethanol extracts, being 2364 and 2334 mg 100 g -1 , respectively. Using a GC-MS method 95 volatiles, in which non-saturated aldehydes were predominant, were identified in the essential oil of seed pomace and in the volatile oil isolated from supercritical extract. The ethanolic extract which is characterised by the highest phenolic content (9443 mg GAE 100 g -1 ) exhibited the highest antioxidant activity (according to the ABTS •+ and DPPH • assays). All pomace extracts examined were of high quality, rich in essential omega fatty acids and with a very high content of bioactive compounds, such as phytosterols and tocopherols. The high nutritional value of extracts from berry seed pomace could justify the commercialisation of specific extracts not only as food additives but also as cosmetic components. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Enhanced radiosyntheses of [¹¹C]raclopride and [¹¹C]DASB using ethanolic loop chemistry.

PubMed

Shao, Xia; Schnau, Paul L; Fawaz, Maria V; Scott, Peter J H

2013-01-01

To improve the synthesis and quality control of carbon-11 labeled radiopharmaceuticals, we report the fully automated loop syntheses of [¹¹C]raclopride and [¹¹C]DASB using ethanol as the only organic solvent for synthesis module cleaning, carbon-11 methylation, HPLC purification, and reformulation. Ethanolic loop chemistry is fully automated using a GE TRACERLab FX(C-Pro) synthesis module, and is readily adaptable to any other carbon-11 synthesis apparatus. Precursors (1 mg) were dissolved in ethanol (100 μL) and loaded into the HPLC loop. [¹¹C]MeOTf was passed through the HPLC loop and then the labeled products were purified by semi-preparative HPLC and reformulated into ethanolic saline. Both [¹¹C]raclopride (3.7% RCY; >95% RCP; SA=20831 Ci/mmol; n=64) and [¹¹C]DASB, both with (3.0% RCY; >95% RCP; SA=15152Ci/mmol; n=9) and without (3.0% RCY; >95% RCP; SA=10931 Ci/mmol; n=3) sodium ascorbate, have been successfully prepared using the described methodology. Doses are suitable for human use and the described methods are now employed for routine clinical production of both radiopharmaceuticals at the University of Michigan. Ethanolic loop chemistry is a powerful technique for preparing [¹¹C]raclopride and [¹¹C]DASB, and we are in the process of adapting it for other carbon-11 radiopharmaceuticals prepared in our laboratories ([¹¹C]PMP, [¹¹C]PBR28 etc.). Copyright © 2013 Elsevier Inc. All rights reserved.

Growth of a Strictly Anaerobic Bacterium on Furfural (2-Furaldehyde)

PubMed Central

Brune, Gerhard; Schoberth, Siegfried M.; Sahm, Hermann

1983-01-01

A strictly anaerobic bacterium was isolated from a continuous fermentor culture which converted the organic constituents of sulfite evaporator condensate to methane and carbon dioxide. Furfural is one of the major components of this condensate. This furfural isolate could degrade furfural as the sole source of carbon and energy in a defined mineral-vitamin-sulfate medium. Acetic acid was the major fermentation product. This organism could also use ethanol, lactate, pyruvate, or fumarate and contained cytochrome c3 and desulfoviridin. Except for furfural degradation, the characteristics of the furfural isolate were remarkably similar to those of the sulfate reducer Desulfovibrio gigas. The furfural isolate has been tentatively identified as Desulfovibrio sp. strain F-1. Images PMID:16346423

Anaerobic biodegradation of cyanide under methanogenic conditions.

PubMed Central

Fallon, R D; Cooper, D A; Speece, R; Henson, M

1991-01-01

Upflow, anaerobic, fixed-bed, activated charcoal biotreatment columns capable of operating at free cyanide concentrations of greater than 100 mg liter-1 with a hydraulic retention time of less than 48 h were developed. Methanogenesis was maintained under a variety of feed medium conditions which included ethanol, phenol, or methanol as the primary reduced carbon source. Under optimal conditions, greater than 70% of the inflow free cyanide was removed in the first 30% of the column height. Strongly complexed cyanides were resistant to removal. Ammonia was the nitrogen end product of cyanide transformation. In cell material removed from the charcoal columns, [14C]bicarbonate was the major carbon end product of [14C]cyanide transformation. PMID:1872600

Fermentation and chemical treatment of pulp and paper mill sludge

DOEpatents

Lee, Yoon Y; Wang, Wei; Kang, Li

2014-12-02

A method of chemically treating partially de-ashed pulp and/or paper mill sludge to obtain products of value comprising taking a sample of primary sludge from a Kraft paper mill process, partially de-ashing the primary sludge by physical means, and further treating the primary sludge to obtain the products of value, including further treating the resulting sludge and using the resulting sludge as a substrate to produce cellulase in an efficient manner using the resulting sludge as the only carbon source and mixtures of inorganic salts as the primary nitrogen source, and including further treating the resulting sludge and using the resulting sludge to produce ethanol.

Tin-oxide-coated single-walled carbon nanotube bundles supporting platinum electrocatalysts for direct ethanol fuel cells.

PubMed

Hsu, Ryan S; Higgins, Drew; Chen, Zhongwei

2010-04-23

Novel tin-oxide (SnO(2))-coated single-walled carbon nanotube (SWNT) bundles supporting platinum (Pt) electrocatalysts for ethanol oxidation were developed for direct ethanol fuel cells. SnO(2)-coated SWNT (SnO(2)-SWNT) bundles were synthesized by a simple chemical-solution route. SnO(2)-SWNT bundles supporting Pt (Pt/SnO(2)-SWNTs) electrocatalysts and SWNT-supported Pt (Pt/SWNT) electrocatalysts were prepared by an ethylene glycol reduction method. The catalysts were physically characterized using TGA, XRD and TEM and electrochemically evaluated through cyclic voltammetry experiments. The Pt/SnO(2)-SWNTs showed greatly enhanced electrocatalytic activity for ethanol oxidation in acid medium, compared to the Pt/SWNT. The optimal SnO(2) loading of Pt/SnO(2)-SWNT catalysts with respect to specific catalytic activity for ethanol oxidation was also investigated.

Fuel ethanol from raw corn by Aspergilli hydrolysis with concurrent yeast fermentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weller, C.L.; Steinberg, M.P.; Rodda, E.D.

Crude amylase preparations were produced by growing Aspergillus awamori and A. niger on raw ground whole corn. These Koji preparations were used to hydrolyze the starch of raw ground whole corn to sugars during simultaneous fermentation of the sugars to ethanol by distillers active dry yeast. Ethanol concentrations of the fermentation beers were determined with gas chromatography. These fermentations yielded an average of 89.6% theoretical ethanol compared to control, conventional, fermentations that had an average of 89.9%. Carbon dioxide evolutions were determined with use of Alwood valves. Both the Koji and conventional fermentations produced an average of 0.48 g ofmore » carbon dioxide per gram of dry substrate starch within 72 h. However, initially the conventional fermentation rate was greater. Koji dehydrated at 41/sup 0/C had no apparent detrimental effects on theoretical ethanol yield. 41 references, 1 figure, 2 tables.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hellwinckel, C.M.; West, Tristram O.; De La Torre Ugarte, D. G.

An integrated, socioeconomic biogeophysical model is used to analyze the interactions of cap-and-trade legislation and the Renewable Fuels Standard. Five alternative policy scenarios were considered with the purpose of identifying policies that act in a synergistic manner to reduce carbon emissions, increase economic returns to agriculture, and adequately meet ethanol mandates.We conclude that climate and energy policies can best be implemented together by offering carbon offset payments to conservation tillage, herbaceous grasses for biomass, and by constraining crop residue removal for ethanol feedstocks to carbon neutral level.

Top-Down Versus Bottom-Up Estimative of CO2 and CO Vehicular Emission Contribution from the Megacity of SãO Paulo, Brazil

NASA Astrophysics Data System (ADS)

Andrade, M.; Nogueira, T.; Martínez, P. J.; Fornaro, A.; Miranda, R. M.; Ynoue, R.

2013-12-01

The Metropolitan Area of São Paulo (MASP) is composed by 39 municipalities with a population of 20 million inhabitants in an area of 8,511 km2. The main source of pollutants to the air is the vehicular emission: exhaust and evaporative fuel. The climate is influenced by the sea breeze from the Southeast direction - MASP is approximately 40 km far from the sea; and by the valley- mountain circulation, due to the presence of the Serra do Mar Mountains in the Northwest part of the city. This wind circulation suffers the influence of the heat island due to the high degree of urbanization. The MASP fleet is composed by approximately 7 million passenger cars and freight vehicles, with 85% light duty vehicles (LDVs), 3% heavy-duty diesel vehicles (HDVs, diesel + 5% bio-diesel) and 12% motorcycles. About 55% of LDVs burn a mixture of 78% gasoline and 22% ethanol (gasohol), 4% use hydrous ethanol (95% ethanol and 5% water), 38% are flex-fuel vehicles that are capable of burning both gasohol and hydrous ethanol and 2% use diesel (CETESB, 2013a). The use of gasohol or hydrous ethanol by the flex-fuel is determined by the price of the fuel. Vehicle traffic is the main source of regulated pollutants: carbon monoxide (CO), nitrogen oxides (NOx) and hydrocarbons (HC), and contributes to the formation of inhalable particulate matter emissions (PM10) as well as being the principal source of carbon dioxide (CO2). 97% of all CO emissions, 85% of HC, 82% of NOx, 36% of sulfur dioxide (SO2), and 36% of all PM10 emissions come from mobile sources (CETESB, 2013b). The official inventory is calculated with the botton-up methodology: calculation of the emission factors in dynamometer, estimation of the average distance each kind of vehicles drives per day and the total number of vehicles in circulation. The values considered a deterioration factor due to the vehicle aging. The top-down methodology was performed from measurements performed in experiments in traffic roads and tunnels. The data presented here compared tunnel measurements performed in 2004 and 2011. The official data estimate an emission of 15327 million tons per year of CO2eq (60% by LDV, 38% HDV and 2% motorcycles) and 128 million tons per year of CO. The top-down estimative based on tunnel measurements resulted in values approximately 5 times higher, being the difference more attributable to the estimative of the diesel emission factor. The uncertainties are related to the deterioration of the emission factor with time and the driving pattern. The diurnal variation of CO2 atmospheric concentration is characterized by the mobile source emission pattern. CETESB. Relatório Anual de Qualidade do Ar no Estado de São Paulo 2012. Companhia de Tecnologia de Saneamento Ambiental, São Paulo, Brazil, 2013a. CETESB. Plano de Controle de Poluição Veicular do Estado de São Paulo 2011 /2013. Companhia de Tecnologia de Saneamento Ambiental, São Paulo, Brazil, 2013b.

Biodegradation of munitions compounds by a sulfate reducing bacterial enrichment culture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boopathy, R.; Manning, J.

1997-08-01

The degradation of several munitions compounds was studied. The compounds included 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetraazocine, 2,4,6-trinitrobenzene (TNB), and 2,4-dinitrotoluene. All of the compounds studied were degraded by the sulfate reducing bacterial (SRB) enrichment culture. The SRB culture did not use the munitions compounds as their sole source of carbon. However, all the munitions compounds tested served as the sole source of nitrogen for the SRB culture. Degradation of munitions compounds was achieved by a co-metabolic process. The SRB culture used a variety of carbon sources including pyruvate, ethanol, formate, lactate, and H{sub 2}-CO{sub 2}. The SRB culture was an incompletemore » oxidizer, unable to carry out the terminal oxidation of organic substrates to CO{sub 2} as the sole product, and it did not use acetate or methanol as a carbon source. In addition to serving as nitrogen sources, the munitions compounds also served as electron acceptors in the absence of sulfate. A soil slurry experiment with 5% and 10% munitions compounds-contaminated soil showed that the contaminant TNT was metabolized by the SRB culture in the presence of pyruvate as electron donor. This culture may be useful in decontaminating munitions compounds-contaminated soil and water under anaerobic conditions.« less

Supercritical carbon dioxide-based sterilization of decellularized heart valves

PubMed Central

Hennessy, Ryan S.; Jana, Soumen; Tefft, Brandon J.; Helder, Meghana R.; Young, Melissa D.; Hennessy, Rebecca R.; Stoyles, Nicholas J.; Lerman, Amir

2017-01-01

Objective The goal of this research project encompasses finding the most efficient and effective method of decellularized tissue sterilization. Background Aortic tissue grafts have been utilized to repair damaged or diseased valves. Although, the tissues for grafting are collected aseptically, it does not eradicate the risk of contamination nor disease transfer. Thus, sterilization of grafts is mandatory. Several techniques have been applied to sterilize grafts; however, each technique shows drawbacks. In this study, we compared several sterilization techniques: supercritical carbon dioxide, electrolyzed water, gamma radiation, ethanol-peracetic acid, and hydrogen peroxide for impact on the sterility and mechanical integrity of porcine decellularized aortic valves. Methods Valve sterility was characterized by histology, microbe culture, and electron microscopy. Uniaxial tensile testing was conducted on the valve cusps along their circumferential orientation to study these sterilization techniques on their integrity. Results Ethanol-peracetic acid and supercritical carbon dioxide treated valves were found to be sterile. The tensile strength of supercritical carbon dioxide treated valves (4.28 ± 0.22 MPa) was higher to those valves treated with electrolyzed water, gamma radiation, ethanol-peracetic acid and hydrogen peroxide (1.02 ± 0.15, 1.25 ± 0.25, 3.53 ± 0.41 and 0.37 ± 0.04 MPa, respectively). Conclusions Superior sterility and integrity were found in the decellularized porcine aortic valves with supercritical carbon dioxide sterilization. This sterilization technique may hold promise for other decellularized soft tissues. Summary Sterilization of grafts is essential. Supercritical carbon dioxide, electrolyzed water, gamma radiation, ethanol-peracetic acid, and hydrogen peroxide techniques were compared for impact on sterility and mechanical integrity of porcine decellularized aortic valves. Ethanol-peracetic acid and supercritical carbon dioxide treated valves were found to be sterile using histology, microbe culture and electron microscopy assays. The cusp tensile properties of supercritical carbon dioxide treated valves were higher compared to valves treated with other techniques. Superior sterility and integrity was found in the decellularized valves treated with supercritical carbon dioxide sterilization. This sterilization technique may hold promise for other decellularized soft tissues. PMID:28337488

Lactose/whey utilization and ethanol production by transformed Saccharomyces cerevisiae cells.

PubMed

Porro, D; Martegani, E; Ranzi, B M; Alberghina, L

1992-04-05

Strains of Saccharomyces cerevisiae transformed with a multicopy expression vector bearing both the Escherichia coli beta-galactosidase gene under the control of the upstream activating sequence of the GAL1-10 genes and the GAL4 activator gene release part of beta-galactosidase in the growth medium. This release is due to cell lysis of the older mother cells; the enzyme maintains its activity in buffered growth media. Fermentation studies with transformed yeast strains showed that the release of beta-galactosidase allowed an efficient growth on buffered media containing lactose as carbon source as well as on whey-based media. The transformed strains utilized up to 95% of the lactose and a high growth yield was obtained in rich media. High productions of ethanol were also observed in stationary phase after growth in lactose minimal media.

Dynamic behaviors and transport properties of ethanol molecules in transmembrane cyclic peptide nanotubes.

PubMed

Li, Rui; Fan, Jianfen; Li, Hui; Yan, Xiliang; Yu, Yi

2015-07-07

Classical molecular dynamics simulations have been performed to investigate the dynamic behaviors and transport properties of ethanol molecules in transmembrane cyclic peptide nanotubes (CPNTs) with various radii, i.e., 8×(WL¯)n=3,4,5/POPE. The results show that ethanol molecules spontaneously fill the octa- and deca-CPNTs, but not the hexa-CPNT. In the octa-CPNT, ethanol molecules are trapped at individual gaps with their carbon skeletons perpendicular to the tube axis and hydroxyl groups towards the tube wall, forming a broken single-file chain. As the channel radius increases, ethanol molecules inside the deca-CPNT tend to form a tubular layer and the hydroxyl groups mainly stretch towards the tube axis. Computations of diffusion coefficients indicate that ethanol molecules in the octa-CPNT nearly lost their diffusion abilities, while those in the deca-CPNT diffuse as 4.5 times as in a (8, 8) carbon nanotube with a similar tube diameter. The osmotic and diffusion permeabilities (pf and pd, respectively) of the octa- and deca-CPNTs transporting ethanol were deduced for the first time. The distributions of the gauche and trans conformers of ethanol molecules in two CPNTs are quite similar, both with approximately 57% gauche conformers. The non-bonded interactions of channel ethanol with a CPNT wall and surrounding ethanol were explored. The potential of mean force elucidates the mechanism underlying the transporting characteristics of channel ethanol in a transmembrane CPNT.

Improved reaction kinetics and selectivity by the TiO2-embedded carbon nanofiber support for electro-oxidation of ethanol on PtRu nanoparticles

NASA Astrophysics Data System (ADS)

Nakagawa, Nobuyoshi; Ito, Yudai; Tsujiguchi, Takuya; Ishitobi, Hirokazu

2014-02-01

The electro-oxidation of ethanol by the catalyst of PtRu nanoparticles supported on a TiO2-embedded carbon nanofiber (PtRu/TECNF), which has recently been proposed by the authors as a highly active catalyst for methanol oxidation, is investigated by cyclic voltammetry using a glassy carbon electrode and by operating a direct ethanol fuel cell (DEFC) with the catalyst. The mass activity obtained from the cyclic voltammogram for the ethanol oxidation is compared to that for the methanol oxidation reported in our recent paper. The mass activity for the ethanol oxidation is comparable or slightly higher than that for the methanol oxidation, and the relationship between the TECNF composition, i.e., the Ti/C mass ratio, and the activity are also similar to that for the methanol oxidation. A DEFC fabricated with the PtRu/TECNF shows a higher power output compared to that with the commercial PtRu/C catalyst. An analysis of the reaction products by a simple two-step reaction model reveals that the PtRu/TECNF increases the rate constant for the reaction steps from ethanol to acetaldehyde and subsequently to CO2, but decreases that from acetaldehyde to acetic acid. This means that the PtRu/TECNF improves not only the kinetics, but also the selectivity to acetaldehyde.

Life of Sugar: Developing Lifecycle Methods to Evaluate the Energy and Environmental Impacts of Sugarcane Biofuels

NASA Astrophysics Data System (ADS)

Gopal, Anand Raja

Lifecycle Assessment (LCA) is undergoing a period of rapid change as it strives to become more policy-relevant. Attributional LCA, the traditional LCA category, is beginning to be seen as particularly ill-equipped to assess the consequences of a policy. This has given birth to a new category of LCA known as Consequential LCA that is designed for use in LCA-based policies but is still largely unknown, even to LCA experts, and suffers from a lack of well developed methods. As a result, many LCA-based policies, like the California Low Carbon Fuel Standard (LCFS), use poor LCA methods that are both scientifically suspect and unable to model many biofuels, especially ones manufactured from byproduct feedstocks. Biofuels made from byproduct feedstocks, primarily molasses ethanol from Asia and the Caribbean, can contribute significantly to LCFS' carbon intensity targets in the near-term at low costs, a desperate need for the policy ever since US corn ethanol was rated as having a worse global warming impact than gasoline. In this dissertation, I develop the first fully consequential lifecycle assessment of a byproduct-based biofuel using a partial equilibrium foundation. I find that the lifecycle carbon content of Indian molasses ethanol is just 5 gCO2/MJ using this method, making it one of the cleanest first generation biofuels in the LCFS. I also show that Indian molasses ethanol remains one of the cleanest first-generation biofuels even when using the flawed methodology ratified for the LCFS, with a lifecycle carbon content of 24 gCO2/MJ. My fully consequential LCA model also shows that India's Ethanol Blending program, which currently subsidizes blending of molasses ethanol and gasoline for domestic consumption, can meet its objective of supporting domestic agriculture more cost-effectively by helping producers export their molasses ethanol to fuel markets that value carbon. However, this objective will be achieved at a significant cost to the poor who will face a 39% increase in the price of sorghum because of the policy.

Screening of Microorganisms Producing Cold-Active Oxidoreductases to Be Applied in Enantioselective Alcohol Oxidation. An Antarctic Survey

PubMed Central

Araújo, Lidiane S.; Kagohara, Edna; Garcia, Thaís P.; Pellizari, Vivian H.; Andrade, Leandro H.

2011-01-01

Several microorganisms were isolated from soil/sediment samples of Antarctic Peninsula. The enrichment technique using (RS)-1-(phenyl)ethanol as a carbon source allowed us to isolate 232 psychrophile/psychrotroph microorganisms. We also evaluated the enzyme activity (oxidoreductases) for enantioselective oxidation reactions, by using derivatives of (RS)-1-(phenyl)ethanol as substrates. Among the studied microorganisms, 15 psychrophile/psychrotroph strains contain oxidoreductases that catalyze the (S)-enantiomer oxidation from racemic alcohols to their corresponding ketones. Among the identified microorganisms, Flavobacterium sp. and Arthrobacter sp. showed excellent enzymatic activity. These new bacteria strains were selected for optimization study, in which the (RS)-1-(4-methyl-phenyl)ethanol oxidation was evaluated in several reaction conditions. From these studies, it was observed that Flavobacterium sp. has an excellent enzymatic activity at 10 °C and Arthrobacter sp. at 15 and 25 °C. We have also determined the growth curves of these bacteria, and both strains showed optimum growth at 25 °C, indicating that these bacteria are psychrotroph. PMID:21673897

A novel process-based model of microbial growth: self-inhibition in Saccharomyces cerevisiae aerobic fed-batch cultures.

PubMed

Mazzoleni, Stefano; Landi, Carmine; Cartenì, Fabrizio; de Alteriis, Elisabetta; Giannino, Francesco; Paciello, Lucia; Parascandola, Palma

2015-07-30

Microbial population dynamics in bioreactors depend on both nutrients availability and changes in the growth environment. Research is still ongoing on the optimization of bioreactor yields focusing on the increase of the maximum achievable cell density. A new process-based model is proposed to describe the aerobic growth of Saccharomyces cerevisiae cultured on glucose as carbon and energy source. The model considers the main metabolic routes of glucose assimilation (fermentation to ethanol and respiration) and the occurrence of inhibition due to the accumulation of both ethanol and other self-produced toxic compounds in the medium. Model simulations reproduced data from classic and new experiments of yeast growth in batch and fed-batch cultures. Model and experimental results showed that the growth decline observed in prolonged fed-batch cultures had to be ascribed to self-produced inhibitory compounds other than ethanol. The presented results clarify the dynamics of microbial growth under different feeding conditions and highlight the relevance of the negative feedback by self-produced inhibitory compounds on the maximum cell densities achieved in a bioreactor.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holser, Ronald A.; King, J. W.; Bost, G.

The genus Hibiscus exhibits great diversity in the production of natural materials with edible and industrial applications. The seeds of twelve varieties of Hibiscus were investigated as a source for triglycerides and phospholipids that could be used in functional foods. Lipid components were extracted from seed samples ground to a nominal particle diameter of 0.1 mm. Extractions were performed with an ISCO model 3560 supercritical fluid extractor using carbon dioxide and a mixture of carbon dioxide modified with ethanol. The neutral lipids were extracted with carbon dioxide at 80 C and 5370 MPa for 45 min. Polar lipids were subsequentlymore » extracted with a mixture of carbon dioxide and 15% ethanol at the same temperature and pressure. High performance liquid chromatography (HPLC) was used to analyze extracts for major neutral and polar lipid classes. A silica column was used with a solvent gradient of hexane/isopropanol/ water and ultraviolet (UV) and evaporative light scattering detectors (ELSD). An aliquot of each triglyceride fraction was trans-methylated with sodium methoxide and analyzed by gas chromatography to obtain the corresponding fatty acid methyl esters. The total lipids extracted ranged from 8.5% for a variety indigenous to Madagascar (H. calyphyllus) to 20% for a hybrid species (Georgia Rose). The average oil yield was 11.4% for the other varieties tested. The fatty acid methyl ester analysis displayed a high degree of unsaturation for all varieties tested, e. g., 75 ' 83%. Oleic, linoleic, and linolenic fatty acids were the predominate unsaturated fatty acids with only minor amounts of C14, C18, and C20 saturated fatty acids measured. Palmitic acid was identified as the predominate saturated fatty acid. The distribution of the major phospholipids, i. e., phosphatidylethanolamine, phosphatidic acid, phosphatidylserine, phosphatidylcholine, and lysophosphatidylcholine, was found to vary significantly among the hibiscus species examined. Phosphatidylcholine and lysophosphatidylcholine were the predominate phospholipids comprising between 50 and 95% of the total phospholipids present. Pressurized extraction techniques provide a rapid method to separate both polar and nonpolar lipids from Hibiscus seeds using carbon dioxide and ethanol mixtures. The seeds require a minimum of processing prior to extraction and the extracts obtained are solvent free and suitable for edible products.« less

Application of acetate buffer in pH adjustment of sorghum mash and its influence on fuel ethanol fermentation.

PubMed

Zhao, Renyong; Bean, Scott R; Crozier-Dodson, Beth Ann; Fung, Daniel Y C; Wang, Donghai

2009-01-01

A 2 M sodium acetate buffer at pH 4.2 was tried to simplify the step of pH adjustment in a laboratory dry-grind procedure. Ethanol yields or conversion efficiencies of 18 sorghum hybrids improved significantly with 2.0-5.9% (3.9% on average) of relative increases when the method of pH adjustment changed from traditional HCl to the acetate buffer. Ethanol yields obtained using the two methods were highly correlated (R (2) = 0.96, P < 0.0001), indicating that the acetate buffer did not influence resolution of the procedure to differentiate sorghum hybrids varying in fermentation quality. Acetate retarded the growth of Saccharomyces cerevisiae, but did not affect the overall fermentation rate. With 41-47 mM of undissociated acetic acid in mash of a sorghum hybrid at pH 4.7, rates of glucose consumption and ethanol production were inhibited during exponential phase but promoted during stationary phase. The maximum growth rate constants (mu(max)) were 0.42 and 0.32 h(-1) for cells grown in mashes with pH adjusted by HCl and the acetate buffer, respectively. Viable cell counts of yeast in mashes with pH adjusted by the acetate buffer were 36% lower than those in mashes adjusted by HCl during stationary phase. Coupled to a 5.3% relative increase in ethanol, a 43.6% relative decrease in glycerol was observed, when the acetate buffer was substituted for HCl. Acetate helped to transfer glucose to ethanol more efficiently. The strain tested did not use acetic acid as carbon source. It was suggested that decreased levels of ATP under acetate stress stimulate glycolysis to ethanol formation, increasing its yield at the expense of biomass and glycerol production.

Gas Fermentation-A Flexible Platform for Commercial Scale Production of Low-Carbon-Fuels and Chemicals from Waste and Renewable Feedstocks.

PubMed

Liew, FungMin; Martin, Michael E; Tappel, Ryan C; Heijstra, Björn D; Mihalcea, Christophe; Köpke, Michael

2016-01-01

There is an immediate need to drastically reduce the emissions associated with global fossil fuel consumption in order to limit climate change. However, carbon-based materials, chemicals, and transportation fuels are predominantly made from fossil sources and currently there is no alternative source available to adequately displace them. Gas-fermenting microorganisms that fix carbon dioxide (CO2) and carbon monoxide (CO) can break this dependence as they are capable of converting gaseous carbon to fuels and chemicals. As such, the technology can utilize a wide range of feedstocks including gasified organic matter of any sort (e.g., municipal solid waste, industrial waste, biomass, and agricultural waste residues) or industrial off-gases (e.g., from steel mills or processing plants). Gas fermentation has matured to the point that large-scale production of ethanol from gas has been demonstrated by two companies. This review gives an overview of the gas fermentation process, focusing specifically on anaerobic acetogens. Applications of synthetic biology and coupling gas fermentation to additional processes are discussed in detail. Both of these strategies, demonstrated at bench-scale, have abundant potential to rapidly expand the commercial product spectrum of gas fermentation and further improve efficiencies and yields.

Gas Fermentation—A Flexible Platform for Commercial Scale Production of Low-Carbon-Fuels and Chemicals from Waste and Renewable Feedstocks

PubMed Central

Liew, FungMin; Martin, Michael E.; Tappel, Ryan C.; Heijstra, Björn D.; Mihalcea, Christophe; Köpke, Michael

2016-01-01

There is an immediate need to drastically reduce the emissions associated with global fossil fuel consumption in order to limit climate change. However, carbon-based materials, chemicals, and transportation fuels are predominantly made from fossil sources and currently there is no alternative source available to adequately displace them. Gas-fermenting microorganisms that fix carbon dioxide (CO2) and carbon monoxide (CO) can break this dependence as they are capable of converting gaseous carbon to fuels and chemicals. As such, the technology can utilize a wide range of feedstocks including gasified organic matter of any sort (e.g., municipal solid waste, industrial waste, biomass, and agricultural waste residues) or industrial off-gases (e.g., from steel mills or processing plants). Gas fermentation has matured to the point that large-scale production of ethanol from gas has been demonstrated by two companies. This review gives an overview of the gas fermentation process, focusing specifically on anaerobic acetogens. Applications of synthetic biology and coupling gas fermentation to additional processes are discussed in detail. Both of these strategies, demonstrated at bench-scale, have abundant potential to rapidly expand the commercial product spectrum of gas fermentation and further improve efficiencies and yields. PMID:27242719

Impact of overexpressing NADH kinase on glucose and xylose metabolism in recombinant xylose-utilizing Saccharomyces cerevisiae.

PubMed

Hou, Jin; Vemuri, Goutham N; Bao, Xiaoming; Olsson, Lisbeth

2009-04-01

During growth of Saccharomyces cerevisiae on glucose, the redox cofactors NADH and NADPH are predominantly involved in catabolism and biosynthesis, respectively. A deviation from the optimal level of these cofactors often results in major changes in the substrate uptake and biomass formation. However, the metabolism of xylose by recombinant S. cerevisiae carrying xylose reductase and xylitol dehydrogenase from the fungal pathway requires both NADH and NADPH and creates cofactor imbalance during growth on xylose. As one possible solution to overcoming this imbalance, the effect of overexpressing the native NADH kinase (encoded by the POS5 gene) in xylose-consuming recombinant S. cerevisiae directed either into the cytosol or to the mitochondria was evaluated. The physiology of the NADH kinase containing strains was also evaluated during growth on glucose. Overexpressing NADH kinase in the cytosol redirected carbon flow from CO(2) to ethanol during aerobic growth on glucose and to ethanol and acetate during anaerobic growth on glucose. However, cytosolic NADH kinase has an opposite effect during anaerobic metabolism of xylose consumption by channeling carbon flow from ethanol to xylitol. In contrast, overexpressing NADH kinase in the mitochondria did not affect the physiology to a large extent. Overall, although NADH kinase did not increase the rate of xylose consumption, we believe that it can provide an important source of NADPH in yeast, which can be useful for metabolic engineering strategies where the redox fluxes are manipulated.

High-rate sulphidogenic fluidised-bed treatment of metal-containing wastewater at high temperature.

PubMed

Sahinkaya, E; Ozkaya, B; Kaksonen, A H; Puhakka, J A

2007-01-01

The applicability of fluidised-bed reactor (FBR) based sulphate reducing bioprocess was investigated for the treatment of iron containing (40-90 mg/L) acidic wastewater at 65 degrees C. The FBR was inoculated with sulphate-reducing bacteria (SRB) originally enriched from a hot mining environment. Ethanol or acetate was supplemented as carbon and electron source for the SRB. A rapid startup with 99.9, 46 and 29% ethanol, sulphate and acetate removals, in respective order, was observed even after 6 days. Iron was almost completely removed with a rate of 90 mg/L.d. The feed pH was decreased gradually from its initial value of 6 to around 3.7 during 100 days of operation. The wastewater pH of 4.3-4.4 was neutralised by the alkalinity produced in acetate oxidation and the average effluent pH was 7.8 +/- 0.8. Although ethanol removal was complete, acetate accumulated. Later the FBR was fed with acetate only. Although acetate was present in the reactor for 295 days, its oxidation rates did not improve, which may be due to low growth rate and poor attachment ability of acetate oxidising SRB. Hence, the oxidation of acetate is the rate limiting step in the sulphidogenic ethanol oxidation by the thermophilic SRB.

Assessing GHG emissions, ecological footprint, and water linkage for different fuels.

PubMed

Chavez-Rodriguez, Mauro F; Nebra, Silvia A

2010-12-15

Currently, transport is highly dependent on fossil fuels and responsible for about 23% of world energy-related GHG (greenhouse gas) emissions. Ethanol from sugar cane and corn emerges as an alternative for gasoline in order to mitigate GHG emissions. Additionally, deeper offshore drilling projects such as in the Brazilian Pre-Salt reservoirs and mining projects of nonconventional sources like Tar Sands in Canada could be a solution for supplying demand of fossil fuels in the short and midterm. Based on updated literature, this paper presents an assessment of GHG emissions for four different fuels: ethanol from sugar cane and from corn and gasoline from conventional crude oil and from tar sands. An Ecological Footprint analysis is also presented, which shows that ethanol from sugar cane has the lowest GHG emissions and requires the lowest biocapacity per unit of energy produced among these fuels. Finally, an analysis using the Embodied Water concept is made with the introduction of a new concept, the "CO(2)-Water", to illustrate the impacts of releasing carbon from underground to atmosphere and of the water needed to sequestrate it over the life cycle of the assessed fuels. Using this method resulted that gasoline from fossil fuels would indirectly "require" on average as much water as ethanol from sugar cane per unit of fuel energy produced.

Chamber studies on nonvented decorative fireplaces using liquid or gelled ethanol fuel.

PubMed

Schripp, Tobias; Salthammer, Tunga; Wientzek, Sebastian; Wensing, Michael

2014-03-18

Decorative ethanol fireplaces are becoming more and more commonly used in many different countries. These fireplaces are constructed such that they have no fume extraction system, and so all of the gases from combustion, volatile organic compounds, and particulate emissions are released into the room. In order to determine the release behavior and the chemical composition of the emissions, a variety of combinations of ethanol fireplaces and fuels were examined in a 48 m(3) emission test chamber under typical living room environmental conditions. Four ethanol fireplaces with 8 different fuels (3 liquid samples, 5 gel-type samples) were tested. The ventilation conditions were set up corresponding to the manufacturers' recommendations and DIN 4734-1. The air concentrations in the chamber were evaluated based on guideline values for indoor air. Of the combustion gases examined, the quantity of carbon dioxide and nitrogen dioxide in particular were close to or even above the guideline values in many cases. A release of components of the fuel (e.g., the denaturing substances) was also detected in the chamber air. In two experiments, a benzene concentration of over 12 ppb and an increased formaldehyde concentration (>0.1 ppm) were identified in the chamber air. The ethanol fireplaces were--irrespective of the type of fuel used--strong sources of fine and ultrafine particles. Overall, ethanol fireplaces have a considerable influence on the quality of the indoor air due to the lack of ventilation. This aspect should--in addition to fire protection--be properly considered when using such devices.

A density functional theory study on the carbon chain growth of ethanol formation on Cu-Co (111) and (211) surfaces

NASA Astrophysics Data System (ADS)

Ren, Bohua; Dong, Xiuqin; Yu, Yingzhe; Wen, Guobin; Zhang, Minhua

2017-08-01

Calculations based on the first-principle density functional theory were carried out to study the most controversial reactions in ethanol formation from syngas on Cu-Co surfaces: CO dissociation mechanism and the key reactions of carbon chain growth of ethanol formation (HCO insertion reactions) on four model surfaces (Cu-Co (111) and (211) with Cu-rich or Co-rich surfaces) to investigate the synergy of the Cu and Co components since the complete reaction network of ethanol formation from syngas is a huge computational burden to calculate on four Cu-Co surface models. We investigated adsorption of important species involved in these reactions, activation barrier and reaction energy of H-assisted dissociation mechanism, directly dissociation of CO, and HCO insertion reactions (CHx + HCO → CHxCHO (x = 1-3)) on four Cu-Co surface models. It was found that reactions on Cu-rich (111) and (211) surfaces all have lower activation barrier in H-assisted dissociation and HCO insertion reactions, especially CH + HCO → CHCHO reaction. The PDOS of 4d orbitals of surface Cu and Co atoms of all surfaces were studied. Analysis of d-band center of Cu and Co atoms and the activation barrier data suggested the correlation between electronic property and catalytic performance. Cu-Co bimetallic with Cu-rich surface allows Co to have higher catalytic activity through the interaction of Cu and Co atom. Then it will improve the adsorption of CO and catalytic activity of Co. Thus it is more favorable to the carbon chain growth in ethanol formation. Our study revealed the factors influencing the carbon chain growth in ethanol production and explained the internal mechanism from electronic property aspect.

Consolidated Bio-Processing of Cellulosic Biomass for Efficient Biofuel Production Using Yeast Consortium

NASA Astrophysics Data System (ADS)

Goyal, Garima

Fossil fuels have been the major source for liquid transportation fuels for ages. However, decline in oil reserves and environmental concerns have raised a lot of interest in alternative and renewable energy sources. One promising alternative is the conversion of plant biomass into ethanol. The primary biomass feed stocks currently being used for the ethanol industry have been food based biomass (corn and sugar cane). However, interest has recently shifted to replace these traditional feed-stocks with more abundant, non-food based cellulosic biomass such as agriculture wastes (corn stover) or crops (switch grass). The use of cellulosic biomass as feed stock for the production of ethanol via bio-chemical routes presents many technical challenges not faced with the use of corn or sugar-cane as feed-stock. Recently, a new process called consolidated Bio-processing (CBP) has been proposed. This process combines simultaneous saccharification of lignocellulose with fermentation of the resulting sugars into a single process step mediated by a single microorganism or microbial consortium. Although there is no natural microorganism that possesses all properties of lignocellulose utilization and ethanol production desired for CBP, some bacteria and fungi exhibit some of the essential traits. The yeast Saccharomyces cerevisiae is the most attractive host organism for the usage of this strategy due to its high ethanol productivity at close to theoretical yields (0.51g ethanol/g glucose consumed), high osmo- and ethanol- tolerance, natural robustness in industrial processes, and ease of genetic manipulation. Introduction of the cellulosome, found naturally in microorganisms, has shown new directions to deal with recalcitrant biomass. In this case enzymes work in synergy in order to hydrolyze biomass more effectively than in case of free enzymes. A microbial consortium has been successfully developed, which ensures the functional assembly of minicellulosome on the yeast surface composed of four yeast populations. These yeast populations include: one displaying scaffoldin on its surface and three populations secreting three different cellulases in the medium to hydrolyze the cellulose. The modular nature of the consortium system allows for the fine-tuning of each population by changing their initial inoculum ratio, thereby optimizing the cellulose hydrolysis and hence ethanol production. When comparing the optimized consortium with equal ratio consortium, the optimized one produced almost double the amount of ethanol (1.87 g/l) with a yield of 0.475 g ethanol/g cellulose. To further evaluate the feasibility of using consortium for CBP, it was grown at very low optical density (OD) under anaerobic conditions. Under stressful conditions like low OD and no oxygen, the consortium system was proficient in assembling the cellulosome on its surface and growing on the PAS-avicel as sole carbon source and concomitantly producing ethanol with a yield of 87% of the theoretical value. For the dynamic study of yeast consortium system, quantitative real time PCR was used to enumerate the individual yeast population in the mixed culture. At the end of the cultivation, ratios of each population in this consortium maintained similar number as the initial inoculums ratios, which further confirms the consortium system is suitable for the application of CBP.

Inhibition of glycine receptor function of native neurons by aliphatic n-alcohols

PubMed Central

Tao, Liang; Ye, Jiang Hong

2002-01-01

The inhibitory effects of n-alcohols (methanol to dodecanol) on glycine-activated currents were studied in neurons freshly dissociated from the ventral tegmental area of neonatal rats using whole-cell patch-clamp recording technique.Ethanol enhanced and depressed glycine-activated currents in 35% and 45%, respectively, of neurons of ventral tegmental area of neonatal rats. In this report, we extended our focus of ethanol-induced inhibition of glycine currents to other straight-chain alcohols.Aliphatic n-alcohols, which have carbon numbers less than nine, suppressed glycine currents in 45% (71/158) of the neurons. All results from this study are obtained from the 45% of cells displaying inhibition; the other 55% of the neurons were not studied.Alcohol potency increased as the number of carbon atoms increased from one to five, and was at a maximal plateau from five to nine; alcohols with 10 or more carbons did not inhibit glycine-activated currents. Thus, a ‘cutoff' point in their potency for inhibition of glycine receptor function occurred at about decanol.A coapplication of dodecanol with ethanol eliminated the inhibition resulting from ethanol. Thus, dodecanol may bind to the receptor silently and compete with ethanol.These observations indicate that straight-chain n-alcohols exhibit a ‘cutoff' point in their potency for inhibition of the glycine receptor function between nine and 10 carbon atoms. The inability of longer alcohols to change the activation properties of the receptors may contribute to the cutoff effect. PMID:12055142

Variation of fermentation redox potential during cell-recycling continuous ethanol operation.

PubMed

Thani, Arthit; Lin, Yen-Han; Laopaiboon, Pattana; Laopaiboon, Lakkana

2016-12-10

Fermentation redox potential was monitored during cell-recycling continuous ethanol operation. The cell-recycling system (CRS) was operated using two hollow fibre (HF) membranes (pore sizes 0.20 and 0.65μm) at three dilution rates (0.02, 0.04 and 0.08h -1 ). Saccharomyces cerevisiae NP 01 were recycled in the fermenter at a recycle ratio of 0.625. Aeration was provided at 2.5vvm for the first 4h and then further supplied continuously at 0.25vvm. As steady state was established, results showed that the fermentation redox potential was lower for processes employing CRS than those without. At the same dilution rates, the sugar utilization and ethanol production with CRS were higher than those without CRS. The highest fermentation efficiency (87.94g/l of ethanol, ∼90% of theoretical yield) was achieved using a 0.2-μm HF membrane CRS at a dilution rate of 0.02h -1 . It was found that 7.53-10.07% of the carbon derived from glucose was incorporated into the yeast. Further, at the same dilution rates, yeast in the processes with CRS incorporated less carbon into ethanol than in those grown without CRS. This result suggests that processes involving CRS utilize more carbon for metabolite synthesis than biomass formation. This indicated that the processes with CRS could utilize more carbon for metabolite synthesis than biomass formation. Copyright © 2016 Elsevier B.V. All rights reserved.

Engineering of Corynebacterium glutamicum for growth and succinate production from levoglucosan, a pyrolytic sugar substrate.

PubMed

Kim, Eun-Mi; Um, Youngsoon; Bott, Michael; Woo, Han Min

2015-10-01

Thermochemical processing provides continuous production of bio-oils from lignocellulosic biomass. Levoglucosan, a pyrolytic sugar substrate C6H10O5 in a bio-oil, has been used for ethanol production using engineered Escherichia coli. Here we provide the first example for succinate production from levoglucosan with Corynebacterium glutamicum, a well-known industrial amino acid producer. Heterologous expression of a gene encoding a sugar kinase from Lipomyces starkeyi, Gibberella zeae or Pseudomonas aeruginosa was employed for levoglucosan conversion in C. glutamicum because the wild type was unable to utilize levoglucosan as sole carbon source. As result, expression of a levoglucosan kinase (LGK) of L. starkeyi only enabled growth with levoglucosan as sole carbon source in CgXII minimal medium by catalyzing conversion of levoglucosan to glucose-6-phosphate. Subsequently, the lgk gene was expressed in an aerobic succinate producer of C. glutamicum, strain BL-1. The recombinant strain showed a higher succinate yield (0.25 g g(-1)) from 2% (w/v) levoglucosan than the reference strain BL-1 from 2% (w/v) glucose (0.19 g g(-1)), confirming that levoglucosan is an attractive carbon substrate for C. glutamicum producer strains. In summary, we demonstrated that a pyrolytic sugar could be a potential carbon source for microbial cell factories. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Transcriptional activator Cat8 is involved in regulation of xylose alcoholic fermentation in the thermotolerant yeast Ogataea (Hansenula) polymorpha.

PubMed

Ruchala, Justyna; Kurylenko, Olena O; Soontorngun, Nitnipa; Dmytruk, Kostyantyn V; Sibirny, Andriy A

2017-02-28

Efficient xylose alcoholic fermentation is one of the key to a successful lignocellulosic ethanol production. However, regulation of this process in the native xylose-fermenting yeasts is poorly understood. In this work, we paid attention to the transcriptional factor Cat8 and its possible role in xylose alcoholic fermentation in Ogataea (Hansenula) polymorpha. In Saccharomyces cerevisiae, organism, which does not metabolize xylose, gene CAT8 encodes a Zn-cluster transcriptional activator necessary for expression of genes involved in gluconeogenesis, respiration, glyoxylic cycle and ethanol utilization. Xylose is a carbon source that could be fermented to ethanol and simultaneously could be used in gluconeogenesis for hexose synthesis. This potentially suggests involvement of CAT8 in xylose metabolism. Here, the role of CAT8 homolog in the natural xylose-fermenting thermotolerant yeast O. polymorpha was characterized. The CAT8 ortholog was identified in O. polymorpha genome and deleted both in the wild-type strain and in advanced ethanol producer from xylose. Constructed cat8Δ strain isolated from wild strain showed diminished growth on glycerol, ethanol and xylose as well as diminished respiration on the last substrate. At the same time, cat8Δ mutant isolated from the best available O. polymorpha ethanol producer showed only visible defect in growth on ethanol. CAT8 deletant was characterized by activated transcription of genes XYL3, DAS1 and RPE1 and slight increase in the activity of several enzymes involved in xylose metabolism and alcoholic fermentation. Ethanol production from xylose in cat8Δ mutants in the background of wild-type strain and the best available ethanol producer from xylose increased for 50 and 30%, respectively. The maximal titer of ethanol during xylose fermentation was 12.5 g ethanol/L at 45 °C. Deletion of CAT8 did not change ethanol production from glucose. Gene CAT8 was also overexpressed under control of the strong constitutive promoter GAP of glyceraldehyde-3-phosphate dehydrogenase. Corresponding strains showed drop in ethanol production in xylose medium whereas glucose alcoholic fermentation remained unchanged. Available data suggest on specific role of Cat8 in xylose alcoholic fermentation. The CAT8 gene is one of the first identified genes specifically involved in regulation of xylose alcoholic fermentation in the natural xylose-fermenting yeast O. polymorpha.

Replacing process water and nitrogen sources with biogas slurry during cellulosic ethanol production.

PubMed

You, Yang; Wu, Bo; Yang, Yi-Wei; Wang, Yan-Wei; Liu, Song; Zhu, Qi-Li; Qin, Han; Tan, Fu-Rong; Ruan, Zhi-Yong; Ma, Ke-Dong; Dai, Li-Chun; Zhang, Min; Hu, Guo-Quan; He, Ming-Xiong

2017-01-01

Environmental issues, such as the fossil energy crisis, have resulted in increased public attention to use bioethanol as an alternative renewable energy. For ethanol production, water and nutrient consumption has become increasingly important factors being considered by the bioethanol industry as reducing the consumption of these resources would decrease the overall cost of ethanol production. Biogas slurry contains not only large amounts of wastewater, but also the nutrients required for microbial growth, e.g., nitrogen, ammonia, phosphate, and potassium. Therefore, biogas slurry is an attractive potential resource for bioethanol production that could serve as an alternative to process water and nitrogen sources. In this study, we propose a method that replaces the process water and nitrogen sources needed for cellulosic ethanol production by Zymomonas mobilis with biogas slurry. To test the efficacy of these methods, corn straw degradation following pretreatment with diluted NaOH and enzymatic hydrolysis in the absence of fresh water was evaluated. Then, ethanol fermentation using the ethanologenic bacterial strain Z. mobilis ZMT2 was conducted without supplementing with additional nitrogen sources. After pretreatment with 1.34% NaOH (w/v) diluted in 100% biogas slurry and continuous enzymatic hydrolysis for 144 h, 29.19 g/L glucose and 12.76 g/L xylose were generated from 30 g dry corn straw. The maximum ethanol concentration acquired was 13.75 g/L, which was a yield of 72.63% ethanol from the hydrolysate medium. Nearly 94.87% of the ammonia nitrogen was depleted and no nitrate nitrogen remained after ethanol fermentation. The use of biogas slurry as an alternative to process water and nitrogen sources may decrease the cost of cellulosic ethanol production by 10.0-20.0%. By combining pretreatment with NaOH diluted in biogas slurry, enzymatic hydrolysis, and ethanol fermentation, 56.3 kg of ethanol was produced by Z. mobilis ZMT-2 through fermentation of 1000 kg of dried corn straw. In this study, biogas slurry replaced process water and nitrogen sources during cellulosic ethanol production. The results suggest that biogas slurry is a potential alternative to water when pretreating corn straw and, thus, has important potential applications in cellulosic ethanol production from corn straw. This study not only provides a novel method for utilizing biogas slurry, but also demonstrates a means of reducing the overall cost of cellulosic ethanol.

Human acylphosphatase cannot replace phosphoglycerate kinase in Saccharomyces cerevisiae.

PubMed

Van Hoek, P; Modesti, A; Ramponi, G; Kötter, P; van Dijken, J P; Pron, J T

2001-10-01

Human acylphosphatase (h-AP, EC 3.6.1.7) has been reported to catalyse the hydrolysis of the 1-phosphate group of 1,3-diphosphoglycerate. In vivo operation of this reaction in the yeast Saccharomyces cerevisiae would bypass phosphoglycerate kinase and thus reduce the ATP yield from glycolysis. To investigate whether h-AP can indeed replace the S. cerevisiae phosphoglycerate kinase, a multi-copy plasmid carrying the h-AP gene under control of the yeast TDH3 promoter was introduced into a pgk1 delta mutant of S. cerevisiae. A strain carrying the expression vector without the h-AP cassette was used as a reference. For both strains, steady-state carbon- and energy-limited chemostat cultures were obtained at a dilution rate of 0.10 h(-1) on a medium containing a mixture of glucose and ethanol (15% and 85% on a carbon basis, respectively). Although the h-AP strain exhibited a high acylphosphatase activity in cell extracts, switching to glucose as sole carbon and energy source resulted in a complete arrest of glucose consumption and growth. The lack of a functional glycolytic pathway was further evident from the absence of ethanol formation in the presence of excess glucose in the culture. As h-AP cannot replace yeast phosphoglycerate kinase in vivo, the enzyme is not a useful tool to modify the ATP yield of glycolysis in S. cerevisiae.

AC-conductance and capacitance measurements for ethanol vapor detection using carbon nanotube-polyvinyl alcohol composite based devices.

PubMed

Greenshields, Márcia W C C; Meruvia, Michelle S; Hümmelgen, Ivo A; Coville, Neil J; Mhlanga, Sabelo D; Ceragioli, Helder J; Quispe, Jose C Rojas; Baranauskas, Vitor

2011-03-01

We report the preparation of inexpensive ethanol sensor devices using multiwalled carbon nanotube-polyvinyl alcohol composite films deposited onto interdigitated electrodes patterned on phenolite substrates. We investigate the frequency dependent response of the device conductance and capacitance showing that higher sensitivity is obtained at higher frequency if the conductance is used as sensing parameter. In the case of capacitance measurements, higher sensitivity is obtained at low frequency. Ethanol detection at a concentration of 300 ppm in air is demonstrated. More than 80% of the sensor conductance and capacitance variation response occurs in less than 20 s.

Acetobacter ghanensis sp. nov., a novel acetic acid bacterium isolated from traditional heap fermentations of Ghanaian cocoa beans.

PubMed

Cleenwerck, Ilse; Camu, Nicholas; Engelbeen, Katrien; De Winter, Tom; Vandemeulebroecke, Katrien; De Vos, Paul; De Vuyst, Luc

2007-07-01

Twenty-three acetic acid bacteria, isolated from traditional heap fermentations of Ghanaian cocoa beans, were subjected to a polyphasic taxonomic study. The isolates were catalase-positive, oxidase-negative, Gram-negative rods. They oxidized ethanol to acetic acid and were unable to produce 2-ketogluconic acid, 5-ketogluconic acid and 2,5-diketogluconic acid from glucose; therefore, they were tentatively identified as Acetobacter species. 16S rRNA gene sequencing and phylogenetic analysis confirmed their position in the genus Acetobacter, with Acetobacter syzygii and Acetobacter lovaniensis as their closest phylogenetic neighbours. (GTG)(5)-PCR fingerprinting grouped the strains in a cluster that did not contain any type strains of members of the genus Acetobacter. DNA-DNA hybridization with the type strains of all recognized Acetobacter species revealed DNA-DNA relatedness values below the species level. The DNA G+C contents of three selected strains were 56.9-57.3 mol%. The novel strains had phenotypic characteristics that enabled them to be differentiated from phylogenetically related Acetobacter species, i.e. they were motile, did not produce 2-ketogluconic acid or 5-ketogluconic acid from glucose, were catalase-positive and oxidase-negative, grew on yeast extract with 30 % glucose, grew on glycerol (although weakly) but not on maltose or methanol as carbon sources, and did not grow with ammonium as sole nitrogen source and ethanol as carbon source. Based on the genotypic and phenotypic data, the isolates represent a novel species of the genus Acetobacter for which the name Acetobacter ghanensis sp. nov. is proposed. The type strain is R-29337(T) (=430A(T)=LMG 23848(T)=DSM 18895(T)).

Carbon monoxide fermentation to ethanol by Clostridium autoethanogenum in a bioreactor with no accumulation of acetic acid.

PubMed

Abubackar, Haris Nalakath; Veiga, María C; Kennes, Christian

2015-06-01

Fermentation of CO or syngas offers an attractive route to produce bioethanol. However, during the bioconversion, one of the challenges to overcome is to reduce the production of acetic acid in order to minimize recovery costs. Different experiments were done with Clostridium autoethanogenum. With the addition of 0.75 μM tungsten, ethanol production from carbon monoxide increased by about 128% compared to the control, without such addition, in batch mode. In bioreactors with continuous carbon monoxide supply, the maximum biomass concentration reached at pH 6.0 was 109% higher than the maximum achieved at pH 4.75 but, interestingly, at pH 4.75, no acetic acid was produced and the ethanol titer reached a maximum of 867 mg/L with minor amounts of 2,3-butanediol (46 mg/L). At the higher pH studied (pH 6.0) in the continuous gas-fed bioreactor, almost equal amounts of ethanol and acetic acid were formed, reaching 907.72 mg/L and 910.69 mg/L respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Oxygen-limited cellobiose fermentation and the characterization of the cellobiase of an industrial Dekkera/Brettanomyces bruxellensis strain.

PubMed

Reis, Alexandre Libanio Silva; de Fátima Rodrigues de Souza, Raquel; Baptista Torres, Rochane Regina Neves; Leite, Fernanda Cristina Bezerra; Paiva, Patrícia Maria Guedes; Vidal, Esteban Espinosa; de Morais, Marcos Antonio

2014-01-01

The discovery of a novel yeast with a natural capacity to produce ethanol from lignocellulosic substrates (second-generation ethanol) is of great significance for bioethanol technology. While there are some yeast strains capable of assimilating cellobiose in aerobic laboratory conditions, the predominant sugar in the treatment of lignocellulosic material, little is known about this ability in real industrial conditions. Fermentations designed to simulate industrial conditions were conducted in synthetic medium with glucose, sucrose, cellobiose and hydrolyzed pre-treated cane bagasse as a different carbon source, with the aim of further characterizing the fermentation capacity of a promising Dekkera bruxellensis yeast strain, isolated from the bioethanol process in Brazil. As a result, it was found (for the first time in oxygen-limiting conditions) that the strain Dekkera bruxellensis GDB 248 could produce ethanol from cellobiose. Moreover, it was corroborated that the cellobiase activity characterizes the enzyme candidate in semi-purified extracts (β-glucosidase). In addition, it was demonstrated that GDB 248 strain had the capacity to produce a higher acetic acid concentration than ethanol and glycerol, which confirms the absence of the Custer effect with this strain in oxygen-limiting conditions. Moreover, it is also being suggested that D. bruxellensis could benefit Saccharomyces cerevisiae and outcompete it in the industrial environment. In this way, it was confirmed that D. bruxellensis GDB 248 has the potential to produce ethanol from cellobiose, and is a promising strain for the fermentation of lignocellulosic substrates.

Effect of Extraction Method on the Oxidative Stability of Camelina Seed Oil Studied by Differential Scanning Calorimetry.

PubMed

Belayneh, Henok D; Wehling, Randy L; Cahoon, Edgar B; Ciftci, Ozan N

2017-03-01

Camelina seed is a new alternative omega-3 source attracting growing interest. However, it is susceptible to oxidation due to its high omega-3 content. The objective of this study was to improve the oxidative stability of the camelina seed oil at the extraction stage in order to eliminate or minimize the use of additive antioxidants. Camelina seed oil extracts were enriched in terms of natural antioxidants using ethanol-modified supercritical carbon dioxide (SC-CO 2 ) extraction. Oxidative stability of the camelina seed oils extracted by ethanol modified SC-CO 2 was studied by differential scanning calorimeter (DSC), and compared with cold press, hexane, and SC-CO 2 methods. Nonisothermal oxidation kinetics of the oils obtained by different extraction methods were studied by DSC at varying heating rates (2.5, 5, 10, and 15 °C/min). Increasing ethanol level in the ethanol-modified SC-CO 2 increased the oxidative stability. Based on oxidation onset temperatures (T on ), SC-CO 2 containing 10% ethanol yielded the most stable oil. Oxidative stability depended on the type and content of the polar fractions, namely, phenolic compounds and phospholipids. Phenolic compounds acted as natural antioxidants, whereas increased phospholipid contents decreased the stability. Study has shown that the oxidative stability of the oils can be improved at the extraction stage and this may eliminate the need for additive antioxidants. © 2017 Institute of Food Technologists®.

Mutations in Alternative Carbon Utilization Pathways in Candida albicans Attenuate Virulence and Confer Pleiotropic Phenotypes▿

PubMed Central

Ramírez, Melissa A.; Lorenz, Michael C.

2007-01-01

The interaction between Candida albicans and cells of the innate immune system is a key determinant of disease progression. Transcriptional profiling has revealed that C. albicans has a complex response to phagocytosis, much of which is similar to carbon starvation. This suggests that nutrient limitation is a significant stress in vivo, and we have shown that glyoxylate cycle mutants are less virulent in mice. To examine whether other aspects of carbon metabolism are important in vivo during an infection, we have constructed strains lacking FOX2 and FBP1, which encode key components of fatty acid β-oxidation and gluconeogenesis, respectively. As expected, fox2Δ mutants failed to utilize several fatty acids as carbon sources. Surprisingly, however, these mutants also failed to grow in the presence of several other carbon sources, whose assimilation is independent of β-oxidation, including ethanol and citric acid. Mutants lacking the glyoxylate enzyme ICL1 also had more severe carbon utilization phenotypes than were expected. These results suggest that the regulation of alternative carbon metabolism in C. albicans is significantly different from that in other fungi. In vivo, fox2Δ mutants show a moderate but significant reduction in virulence in a mouse model of disseminated candidiasis, while disruption of the glyoxylate cycle or gluconeogenesis confers a severe attenuation in this model. These data indicate that C. albicans often encounters carbon-poor conditions during growth in the host and that the ability to efficiently utilize multiple nonfermentable carbon sources is a virulence determinant. Consistent with this in vivo requirement, C. albicans uniquely regulates carbon metabolism in a more integrated manner than in Saccharomyces cerevisiae, such that defects in one part of the machinery have wider impacts than expected. These aspects of alternative carbon metabolism may then be useful as targets for therapeutic intervention. PMID:17158734

Emissions of organic carbon and methane from petroleum and dairy operations in California's San Joaquin Valley

NASA Astrophysics Data System (ADS)

Gentner, D. R.; Ford, T. B.; Guha, A.; Boulanger, K.; Brioude, J.; Angevine, W. M.; de Gouw, J. A.; Warneke, C.; Gilman, J. B.; Ryerson, T. B.; Peischl, J.; Meinardi, S.; Blake, D. R.; Atlas, E.; Lonneman, W. A.; Kleindienst, T. E.; Beaver, M. R.; St. Clair, J. M.; Wennberg, P. O.; VandenBoer, T. C.; Markovic, M. Z.; Murphy, J. G.; Harley, R. A.; Goldstein, A. H.

2014-05-01

Petroleum and dairy operations are prominent sources of gas-phase organic compounds in California's San Joaquin Valley. It is essential to understand the emissions and air quality impacts of these relatively understudied sources, especially for oil/gas operations in light of increasing US production. Ground site measurements in Bakersfield and regional aircraft measurements of reactive gas-phase organic compounds and methane were part of the CalNex (California Research at the Nexus of Air Quality and Climate Change) project to determine the sources contributing to regional gas-phase organic carbon emissions. Using a combination of near-source and downwind data, we assess the composition and magnitude of emissions, and provide average source profiles. To examine the spatial distribution of emissions in the San Joaquin Valley, we developed a statistical modeling method using ground-based data and the FLEXPART-WRF transport and meteorological model. We present evidence for large sources of paraffinic hydrocarbons from petroleum operations and oxygenated compounds from dairy (and other cattle) operations. In addition to the small straight-chain alkanes typically associated with petroleum operations, we observed a wide range of branched and cyclic alkanes, most of which have limited previous in situ measurements or characterization in petroleum operation emissions. Observed dairy emissions were dominated by ethanol, methanol, acetic acid, and methane. Dairy operations were responsible for the vast majority of methane emissions in the San Joaquin Valley; observations of methane were well correlated with non-vehicular ethanol, and multiple assessments of the spatial distribution of emissions in the San Joaquin Valley highlight the dominance of dairy operations for methane emissions. The petroleum operations source profile was developed using the composition of non-methane hydrocarbons in unrefined natural gas associated with crude oil. The observed source profile is consistent with fugitive emissions of condensate during storage or processing of associated gas following extraction and methane separation. Aircraft observations of concentration hotspots near oil wells and dairies are consistent with the statistical source footprint determined via our FLEXPART-WRF-based modeling method and ground-based data. We quantitatively compared our observations at Bakersfield to the California Air Resources Board emission inventory and find consistency for relative emission rates of reactive organic gases between the aforementioned sources and motor vehicles in the region. We estimate that petroleum and dairy operations each comprised 22% of anthropogenic non-methane organic carbon at Bakersfield and were each responsible for 8-13% of potential precursors to ozone. Yet, their direct impacts as potential secondary organic aerosol (SOA) precursors were estimated to be minor for the source profiles observed in the San Joaquin Valley.

Policy implications of allocation methods in the life cycle analysis of integrated corn and corn stover ethanol production

DOE PAGES

Canter, Christina E.; Dunn, Jennifer B.; Han, Jeongwoo; ...

2015-08-18

Here, a biorefinery may produce multiple fuels from more than one feedstock. The ability of these fuels to qualify as one of the four types of biofuels under the US Renewable Fuel Standard and to achieve a low carbon intensity score under California’s Low Carbon Fuel Standard can be strongly influenced by the approach taken to their life cycle analysis (LCA). For example, in facilities that may co-produce corn grain and corn stover ethanol, the ethanol production processes can share the combined heat and power (CHP) that is produced from the lignin and liquid residues from stover ethanol production. Wemore » examine different LCA approaches to corn grain and stover ethanol production considering different approaches to CHP treatment. In the baseline scenario, CHP meets the energy demands of stover ethanol production first, with additional heat and electricity generated sent to grain ethanol production. The resulting greenhouse gas (GHG) emissions for grain and stover ethanol are 57 and 25 g-CO 2eq/MJ, respectively, corresponding to a 40 and 74% reduction compared to the GHG emissions of gasoline. We illustrate that emissions depend on allocation of burdens of CHP production and corn farming, along with the facility capacities. Co-product handling techniques can strongly influence LCA results and should therefore be transparently documented.« less

Policy implications of allocation methods in the life cycle analysis of integrated corn and corn stover ethanol production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Canter, Christina E.; Dunn, Jennifer B.; Han, Jeongwoo

Here, a biorefinery may produce multiple fuels from more than one feedstock. The ability of these fuels to qualify as one of the four types of biofuels under the US Renewable Fuel Standard and to achieve a low carbon intensity score under California’s Low Carbon Fuel Standard can be strongly influenced by the approach taken to their life cycle analysis (LCA). For example, in facilities that may co-produce corn grain and corn stover ethanol, the ethanol production processes can share the combined heat and power (CHP) that is produced from the lignin and liquid residues from stover ethanol production. Wemore » examine different LCA approaches to corn grain and stover ethanol production considering different approaches to CHP treatment. In the baseline scenario, CHP meets the energy demands of stover ethanol production first, with additional heat and electricity generated sent to grain ethanol production. The resulting greenhouse gas (GHG) emissions for grain and stover ethanol are 57 and 25 g-CO 2eq/MJ, respectively, corresponding to a 40 and 74% reduction compared to the GHG emissions of gasoline. We illustrate that emissions depend on allocation of burdens of CHP production and corn farming, along with the facility capacities. Co-product handling techniques can strongly influence LCA results and should therefore be transparently documented.« less

Impact of carbon monoxide partial pressures on methanogenesis and medium chain fatty acids production during ethanol fermentation.

PubMed

Esquivel-Elizondo, Sofia; Miceli, Joseph; Torres, Cesar I; Krajmalnik-Brown, Rosa

2018-02-01

Medium-chain fatty acids (MCFA) are important biofuel precursors. Carbon monoxide (CO) is a sustainable electron and carbon donor for fatty acid elongation, since it is metabolized to MCFA precursors, it is toxic to most methanogens, and it is a waste product generated in the gasification of waste biomass. The main objective of this work was to determine if the inhibition of methanogenesis through the continuous addition of CO would lead to increased acetate or MCFA production during fermentation of ethanol. The effects of CO partial pressures (P CO ; 0.08-0.3 atm) on methanogenesis, fatty acids production, and the associated microbial communities were studied in batch cultures fed with CO and ethanol. Methanogenesis was partially inhibited at P CO  ≥ 0.11 atm. This inhibition led to increased acetate production during the first phase of fermentation (0-19 days). However, a second addition of ethanol (day 19) triggered MCFA production only at P CO  ≥ 0.11 atm, which probably occurred through the elongation of acetate with CO-derived ethanol and H 2 :CO 2 . Accordingly, during the second phase of fermentation (days 20-36), the distribution of electrons to acetate decreased at higher P CO , while electrons channeled to MCFA increased. Most probably, Acetobacterium, Clostridium, Pleomorphomonas, Oscillospira, and Blautia metabolized CO to H 2 :CO 2 , ethanol and/or fatty acids, while Peptostreptococcaceae, Lachnospiraceae, and other Clostridiales utilized these metabolites, along with the provided ethanol, for MCFA production. These results are important for biotechnological systems where fatty acids production are preferred over methanogenesis, such as in chain elongation systems and microbial fuel cells. © 2017 Wiley Periodicals, Inc.

A step towards on-chip biochemical energy cascade of microorganisms: carbon dioxide generation induced by ethanol fermentation in 3D printed modular lab-on-a-chip

NASA Astrophysics Data System (ADS)

Podwin, A.; Kubicki, W.; Adamski, K.; Walczak, R.; Dziuban, J. A.

2016-11-01

The concept of biochemical energy cascade of microorganisms towards oxygen generation in 3D printed lab-on-a-chip has been presented. In this work, carbon dioxide - a product of ethanol fermentation of yeasts has been utilized to enable light-initialized photosynthesis of euglenas and as a result of their metabolic transitions produce pure oxygen.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hellwinckel, Chad; de la Torre Ugarte, Daniel; Perlack, Robert D

An integrated, socioeconomic biogeophysical model is used to analyze the interactions of cap-and-trade legislation and the Renewable Fuels Standard. Five alternative policy scenarios were considered with the purpose of identifying policies that act in a synergistic manner to reduce carbon emissions, increase economic returns to agriculture, and adequately meet ethanol mandates. We conclude that climate and energy policies can best be implemented together by offering carbon offset payments to conservation tillage, herbaceous grasses for biomass, and by constraining crop residue removal for ethanol feedstocks to carbon neutral level. When comparing this scenario to the Baseline scenario, the agricultural sector realizesmore » an economic benefit of US$156 billion by 2030 and emissions are reduced by 135 Tg C-equivalent (Eq) yr 1. Results also indicate that geographic location of cellulosic feedstocks could shift significantly depending on the final policies implemented in cap and trade legislation. Placement of cellulosic ethanol facilities should consider these possible shifts when determining site location.« less

The influence of Adh function on ethanol preference and tolerance in adult Drosophila melanogaster.

PubMed

Ogueta, Maite; Cibik, Osman; Eltrop, Rouven; Schneider, Andrea; Scholz, Henrike

2010-11-01

Preference determines behavioral choices such as choosing among food sources and mates. One preference-affecting chemical is ethanol, which guides insects to fermenting fruits or leaves. Here, we show that adult Drosophila melanogaster prefer food containing up to 5% ethanol over food without ethanol and avoid food with high levels (23%) of ethanol. Although female and male flies behaved differently at ethanol-containing food sources, there was no sexual dimorphism in the preference for food containing modest ethanol levels. We also investigated whether Drosophila preference, sensitivity and tolerance to ethanol was related to the activity of alcohol dehydrogenase (Adh), the primary ethanol-metabolizing enzyme in D. melanogaster. Impaired Adh function reduced ethanol preference in both D. melanogaster and a related species, D. sechellia. Adh-impaired flies also displayed reduced aversion to high ethanol concentrations, increased sensitivity to the effects of ethanol on postural control, and negative tolerance/sensitization (i.e., a reduction of the increased resistance to ethanol's effects that normally occurs upon repeated exposure). These data strongly indicate a linkage between ethanol-induced behavior and ethanol metabolism in adult fruit flies: Adh deficiency resulted in reduced preference to low ethanol concentrations and reduced aversion to high ones, despite recovery from ethanol being strongly impaired.

Delivery and Establishing Slow Release Carbon Source to the Hanford Vadose Zone Using Colloidal Silica Suspension Injection and Subsequent Gelation - Laboratory Study

NASA Astrophysics Data System (ADS)

Zhong, L.; Lee, M. H.; Lee, B.; Yang, S.

2016-12-01

Delivery of nutrient to and establish a slow release carbon source in the vadose zone and capillary fringe zone is essential for setting up of a long-lasting bioremediation of contaminations in those zones. Conventional solution-based injection and infiltration approaches are facing challenges to achieve the delivery and remedial goals. Aqueous silica suspensions undergo a delayed gelation process under favorite geochemical conditions. The delay in gelation provides a time window for the injection of the suspension into the subsurface; and the gelation of the amendment-silica suspension enables the amendment-laden gel to stay in the target zone and slowly release the constituents for contaminant remediation. This approach can potentially be applied to deliver bio-nutrients to the vadose zone and capillary fringe zone for enhanced bioremediation and achieve remedial goals. This research was conducted to demonstrate delayed gelation of colloidal silica suspensions when carbon sources were added and to prove the gelation occurs in sediments under vadose conditions. Sodium lactate, vegetable oil, ethanol, and molasses were tested as the examples of carbon source (or nutrient) amendments. The rheological properties of the silica suspensions during the gelation were characterized. The influence of silica, salinity, nutrient concentrations, and the type of nutrients was studied. The kinetics of nutrient release from silica-nutrient gel was quantified using molasses as the example, and the influence of suspension gelation time was evaluated. The injection behavior of the suspensions was investigated by monitoring their viscosity changes and the injection pressures when the suspensions were delivered into sediment columns.

Bioenergy crop productivity and potential climate change mitigation from marginal lands in the United States: An ecosystem modeling perspective

DOE PAGES

Qin, Zhangcai; Zhuang, Qianlai; Cai, Ximing

2014-06-16

Growing biomass feedstocks from marginal lands is becoming an increasingly attractive choice for producing biofuel as an alternative energy to fossil fuels. Here, we used a biogeochemical model at ecosystem scale to estimate crop productivity and greenhouse gas (GHG) emissions from bioenergy crops grown on marginal lands in the United States. Two broadly tested cellulosic crops, switchgrass, and Miscanthus, were assumed to be grown on the abandoned land and mixed crop–vegetation land with marginal productivity. Production of biomass and biofuel as well as net carbon exchange and nitrous oxide emissions were estimated in a spatially explicit manner. We found that,more » cellulosic crops, especially Miscanthus could produce a considerable amount of biomass, and the effective ethanol yield is high on these marginal lands. For every hectare of marginal land, switchgrass and Miscanthus could produce 1.0–2.3 kl and 2.9–6.9 kl ethanol, respectively, depending on nitrogen fertilization rate and biofuel conversion efficiency. Nationally, both crop systems act as net GHG sources. Switchgrass has high global warming intensity (100–390 g CO 2eq l –1 ethanol), in terms of GHG emissions per unit ethanol produced. Miscanthus, however, emits only 21–36 g CO 2eq to produce every liter of ethanol. To reach the mandated cellulosic ethanol target in the United States, growing Miscanthus on the marginal lands could potentially save land and reduce GHG emissions in comparison to growing switchgrass. Furthermore, the ecosystem modeling is still limited by data availability and model deficiencies, further efforts should be made to classify crop–specific marginal land availability, improve model structure, and better integrate ecosystem modeling into life cycle assessment.« less

Carbon-supported PdM (M = Au and Sn) nanocatalysts for the electrooxidation of ethanol in high pH media

NASA Astrophysics Data System (ADS)

He, Qinggang; Chen, Wei; Mukerjee, Sanjeev; Chen, Shaowei; Laufek, František

Carbon-supported Pd 4Au- and Pd 2.5Sn-alloyed nanoparticles were prepared by a chemical reduction method, and characterized by a wide array of experimental techniques including mass spectrometry, transmission electron microscopy, and X-ray diffraction spectroscopy. Ethanol electrooxidation on the as-synthesized catalysts and commercial Pt/C was then investigated and compared in alkaline media by cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy studies at room temperature. Voltammetric and chronoamperometric measurements showed higher current density and longer term stability in ethanol oxidation with the palladium alloy nanocatalysts than with the commercial one. Electrochemical impedance spectroscopy and Tafel plots were employed to examine the charge-transfer kinetics of ethanol electrooxidation. The results suggest that whereas the reaction kinetics might be somewhat more sluggish on the Pd-based alloy catalysts than on commercial Pt/C, the former appeared to have a higher tolerance to surface poisoning. Overall, the Pd-based alloy catalysts represent promising candidates for the electrocatalytic oxidation of ethanol, and Pd 4Au/C displays the best catalytic activity among the series for the ethanol oxidation in alkaline media.

Unveiling the Interplay Between Diffusing CO2 and Ethanol Molecules in Champagne Wines by Classical Molecular Dynamics and (13)C NMR Spectroscopy.

PubMed

Bonhommeau, David A; Perret, Alexandre; Nuzillard, Jean-Marc; Cilindre, Clara; Cours, Thibaud; Alijah, Alexander; Liger-Belair, Gérard

2014-12-18

The diffusion coefficients of carbon dioxide (CO2) and ethanol (EtOH) in carbonated hydroalcoholic solutions and Champagne wines are evaluated as a function of temperature by classical molecular dynamics (MD) simulations and (13)C NMR spectroscopy measurements. The excellent agreement between theoretical and experimental diffusion coefficients suggest that ethanol is the main molecule, apart from water, responsible for the value of the CO2 diffusion coefficients in typical Champagne wines, a result that could likely be extended to most sparkling wines with alike ethanol concentrations. CO2 and EtOH hydrodynamical radii deduced from viscometry measurements by applying the Stokes-Einstein relationship are found to be mostly constant and in close agreement with MD predictions. The reliability of our approach should be of interest to physical chemists aiming to model transport phenomena in supersaturated aqueous solutions or water/alcohol mixtures.

Recycling Carbon Dioxide during Xylose Fermentation by Engineered Saccharomyces cerevisiae.

PubMed

Xia, Peng-Fei; Zhang, Guo-Chang; Walker, Berkley; Seo, Seung-Oh; Kwak, Suryang; Liu, Jing-Jing; Kim, Heejin; Ort, Donald R; Wang, Shu-Guang; Jin, Yong-Su

2017-02-17

Global climate change caused by the emission of anthropogenic greenhouse gases (GHGs) is a grand challenge to humanity. To alleviate the trend, the consumption of fossil fuels needs to be largely reduced and alternative energy technologies capable of controlling GHG emissions are anticipated. In this study, we introduced a synthetic reductive pentose phosphate pathway (rPPP) into a xylose-fermenting Saccharomyces cerevisiae strain SR8 to achieve simultaneous lignocellulosic bioethanol production and carbon dioxide recycling. Specifically, ribulose-1,5-bisphosphate carboxylase/oxygenase from Rhodospirillum rubrum and phosphoribulokinase from Spinacia oleracea were introduced into the SR8 strain. The resulting strain with the synthetic rPPP was able to exhibit a higher yield of ethanol and lower yields of byproducts (xylitol and glycerol) than a control strain. In addition, the reduced release of carbon dioxide by the engineered strain was observed during xylose fermentation, suggesting that the carbon dioxide generated by pyruvate decarboxylase was partially reassimilated through the synthetic rPPP. These results demonstrated that recycling of carbon dioxide from the ethanol fermentation pathway in yeast can be achieved during lignocellulosic bioethanol production through a synthetic carbon conservative metabolic pathway. This strategy has a great potential to alleviate GHG emissions during the production of second-generation ethanol.

Observational Constraints on the Global Budget of Ethanol

NASA Astrophysics Data System (ADS)

Naik, V.; Fiore, A. M.; Horowitz, L. W.; Singh, H. B.; Wiedinmyer, C.; Guenther, A. B.; de Gouw, J.; Millet, D.; Levy, H.; Oppenheimer, M.

2007-12-01

Ethanol, an oxygenated volatile organic compound (OVOC), is used extensively as a motor fuel and fuel additive to promote clean combustion. Ethanol can affect the oxidizing capacity and the ozone-forming potential of the atmosphere. Limited available atmospheric observations suggest a global background atmospheric ethanol mixing ratio of about 20 pptv, with values up to 3 ppbv near source regions; however, the atmospheric distribution and budget of ethanol remain poorly understood. Here, we use the global three-dimensional chemical transport model MOZART-4 to investigate the global ethanol distribution and budget, and place constraints on the budget by evaluating the model with atmospheric observations. We implement a global ethanol source of 14.7 Tg yr-1 in the model consisting of biogenic emissions (9.2 Tg yr-1), industrial/anthropogenic emissions (3.2 Tg yr-1), emissions from biofuels (1.8 Tg yr-1), biomass burning emissions (0.5 Tg yr-1), and a secondary source from atmospheric production (0.056 Tg yr-1). Gas-phase oxidation by the hydroxyl radical accounts for 66% of the global sink of ethanol in the model, dry deposition 9%, and wet scavenging 25%. The simulation yields a global mean ethanol burden of 0.11 Tg and an atmospheric lifetime of 3 days. The simulated boundary layer mean ethanol concentrations underestimate observations from field campaigns over the United States by 50%, downwind of Asia by 76% and over the remote Pacific Ocean by 86%. Because of the short lifetime of ethanol, the model discrepancy over remote tropical regions cannot be attributed to an underestimate of surface emissions over continents. In these regions, the dominant model source is secondary atmospheric production, from the reaction of the ethyl peroxy radical (C2H5O2) either with itself or with the methyl peroxy radical (CH3O2). A ~500-fold increase in this diffuse source (to ~30 Tg yr-1) distributed uniformly throughout the troposphere would largely correct the observation-model mismatch, resulting in a best estimate of the global ethanol source of 44 Tg yr-1. This finding could indicate omission of other chemical species in the model that can provide additional sources of C2H5O2. Candidate OVOCs, such as propionaldehyde, and peroxypropionic nitric anhydride (PPN) that are precursors to C2H5O2, have been measured in the remote troposphere. This hypothesis, however, needs testing by direct measurements of C2H5O2 in the remote tropical troposphere.

Ethanol production from renewable resources.

PubMed

Gong, C S; Cao, N J; Du, J; Tsao, G T

1999-01-01

Vast amounts of renewable biomass are available for conversion to liquid fuel, ethanol. In order to convert biomass to ethanol, the efficient utilization of both cellulose-derived and hemicellulose-derived carbohydrates is essential. Six-carbon sugars are readily utilized for this purpose. Pentoses, on the other hand, are more difficult to convert. Several metabolic factors limit the efficient utilization of pentoses (xylose and arabinose). Recent developments in the improvement of microbial cultures provide the versatility of conversion of both hexoses and pentoses to ethanol more efficiently. In addition, novel bioprocess technologies offer a promising prospective for the efficient conversion of biomass and recovery of ethanol.

The effect of barium on perceptions of taste intensity and palatability.

PubMed

Dietsch, Angela M; Solomon, Nancy Pearl; Steele, Catriona M; Pelletier, Cathy A

2014-02-01

Barium may affect the perception of taste intensity and palatability. Such differences are important considerations in the selection of dysphagia assessment strategies and interpretation of results. Eighty healthy women grouped by age (younger, older) and genetic taste status (supertaster, nontaster) rated intensity and palatability for seven tastants prepared in deionized water with and without 40 % w/v barium: noncarbonated and carbonated water, diluted ethanol, and high concentrations of citric acid (sour), sodium chloride (salty), caffeine (bitter), and sucrose (sweet). Mixed-model analyses explored the effects of barium, taster status, and age on perceived taste intensity and acceptability of stimuli. Barium was associated with lower taste intensity ratings for sweet, salty, and bitter tastants, higher taste intensity in carbonated water, and lower palatability in water, sweet, sour, and carbonated water. Older subjects reported lower palatability (all barium samples, sour) and higher taste intensity scores (ethanol, sweet, sour) compared to younger subjects. Supertasters reported higher taste intensity (ethanol, sweet, sour, salty, bitter) and lower palatability (ethanol, salty, bitter) than nontasters. Refusal rates were highest for younger subjects and supertasters, and for barium (regardless of tastant), bitter, and ethanol. Barium suppressed the perceived intensity of some tastes and reduced palatability. These effects are more pronounced in older subjects and supertasters, but younger supertasters are least likely to tolerate trials of barium and strong tastant solutions.

An alternative synthetic approach for efficient catalytic conversion of syngas to ethanol.

PubMed

Yue, Hairong; Ma, Xinbin; Gong, Jinlong

2014-05-20

Ethanol is an attractive end product and a versatile feedstock because a widespread market exists for its commercial use as a fuel additive or a potential substitute for gasoline. Currently, ethanol is produced primarily by fermentation of biomass-derived sugars, particularly those containing six carbons, but coproducts 5-carbon sugars and lignin remain unusable. Another major process for commercial production of ethanol is hydration of ethylene over solid acidic catalysts, yet not sustainable considering the depletion of fossil fuels. Catalytic conversion of synthetic gas (CO + H2) could produce ethanol in large quantities. However, the direct catalytic conversion of synthetic gas to ethanol remains challenging, and no commercial process exists as of today although the research has been ongoing for the past 90 years, since such the process suffers from low yield and poor selectivity due to slow kinetics of the initial C-C bond formation and fast chain growth of the C2 intermediates. This Account describes recent developments in an alternative approach for the synthesis of ethanol via synthetic gas. This process is an integrated technology consisting of the coupling of CO with methanol to form dimethyl oxalate and the subsequent hydrogenation to yield ethanol. The byproduct of the second step (methanol) can be separated and used in circulation as the feedstock for the coupling step. The coupling reaction of carbon monoxide for producing dimethyl oxalate takes place under moderate reaction conditions with high selectivity (∼95%), which ideally leads to a self-closing, nonwaste, catalytic cycling process. This Account also summarizes the progress on the development of copper-based catalysts for the hydrogenation reaction with remarkable efficiencies and stability. The unique lamellar structure and the cooperative effect between surface Cu(0) and Cu(+) species are responsible for the activity of the catalyst with high yield of ethanol (∼91%). The understanding of nature of valence states of Cu could also guide the rational design of Cu-based catalysts for other similar reactions, particularly for hydrogenation catalytic systems. In addition, by regulating the reaction condition and the surface structure of the catalysts, the products in the hydrogenation steps, such as ethanol, methyl glycolate, and ethylene glycol, could be tuned efficiently. This synthetic approach enables a more sustainable ethanol, methyl glycolate, and ethylene glycol synthesis in industry and greatly reduces the dependence on petroleum resources and the emission of the greenhouse gas.

Efficient butanol-ethanol (B-E) production from carbon monoxide fermentation by Clostridium carboxidivorans.

PubMed

Fernández-Naveira, Ánxela; Abubackar, Haris Nalakath; Veiga, María C; Kennes, Christian

2016-04-01

The fermentation of waste gases rich in carbon monoxide using acetogens is an efficient way to obtain valuable biofuels like ethanol and butanol. Different experiments were carried out with the bacterial species Clostridium carboxidivorans as biocatalyst. In batch assays with no pH regulation, after complete substrate exhaustion, acetic acid, butyric acid, and ethanol were detected while only negligible butanol production was observed. On the other side, in bioreactors, with continuous carbon monoxide supply and pH regulation, both C2 and C4 fatty acids were initially formed as well as ethanol and butanol at concentrations never reported before for this type of anaerobic bioconversion of gaseous C1 compounds, showing that the operating conditions significantly affect the metabolic fermentation profile and butanol accumulation. Maximum ethanol and butanol concentrations in the bioreactors were obtained at pH 5.75, reaching values of 5.55 and 2.66 g/L, respectively. The alcohols were produced both from CO fermentation as well as from the bioconversion of previously accumulated acetic and butyric acids, resulting in low residual concentrations of such acids at the end of the bioreactor experiments. CO consumption was often around 50% and reached up to more than 80%. Maximum specific rates of ethanol and butanol production were reached at pH 4.75, with values of 0.16 g/h*g of biomass and 0.07 g/h*g of biomass, respectively, demonstrating that a low pH was more favorable to solventogenesis in this process, although it negatively affects biomass growth which does also play a role in the final alcohol titer.

The metabolic costs of improving ethanol yield by reducing glycerol formation capacity under anaerobic conditions in Saccharomyces cerevisiae

PubMed Central

2013-01-01

Background Finely regulating the carbon flux through the glycerol pathway by regulating the expression of the rate controlling enzyme, glycerol-3-phosphate dehydrogenase (GPDH), has been a promising approach to redirect carbon from glycerol to ethanol and thereby increasing the ethanol yield in ethanol production. Here, strains engineered in the promoter of GPD1 and deleted in GPD2 were used to investigate the possibility of reducing glycerol production of Saccharomyces cerevisiae without jeopardising its ability to cope with process stress during ethanol production. For this purpose, the mutant strains TEFmut7 and TEFmut2 with different GPD1 residual expression were studied in Very High Ethanol Performance (VHEP) fed-batch process under anaerobic conditions. Results Both strains showed a drastic reduction of the glycerol yield by 44 and 61% while the ethanol yield improved by 2 and 7% respectively. TEFmut2 strain showing the highest ethanol yield was accompanied by a 28% reduction of the biomass yield. The modulation of the glycerol formation led to profound redox and energetic changes resulting in a reduction of the ATP yield (YATP) and a modulation of the production of organic acids (acetate, pyruvate and succinate). Those metabolic rearrangements resulted in a loss of ethanol and stress tolerance of the mutants, contrarily to what was previously observed under aerobiosis. Conclusions This work demonstrates the potential of fine-tuned pathway engineering, particularly when a compromise has to be found between high product yield on one hand and acceptable growth, productivity and stress resistance on the other hand. Previous study showed that, contrarily to anaerobiosis, the resulting gain in ethanol yield was accompanied with no loss of ethanol tolerance under aerobiosis. Moreover those mutants were still able to produce up to 90 gl-1 ethanol in an anaerobic SSF process. Fine tuning metabolic strategy may then open encouraging possibilities for further developing robust strains with improved ethanol yield. PMID:23537043

The metabolic costs of improving ethanol yield by reducing glycerol formation capacity under anaerobic conditions in Saccharomyces cerevisiae.

PubMed

Pagliardini, Julien; Hubmann, Georg; Alfenore, Sandrine; Nevoigt, Elke; Bideaux, Carine; Guillouet, Stephane E

2013-03-28

Finely regulating the carbon flux through the glycerol pathway by regulating the expression of the rate controlling enzyme, glycerol-3-phosphate dehydrogenase (GPDH), has been a promising approach to redirect carbon from glycerol to ethanol and thereby increasing the ethanol yield in ethanol production. Here, strains engineered in the promoter of GPD1 and deleted in GPD2 were used to investigate the possibility of reducing glycerol production of Saccharomyces cerevisiae without jeopardising its ability to cope with process stress during ethanol production. For this purpose, the mutant strains TEFmut7 and TEFmut2 with different GPD1 residual expression were studied in Very High Ethanol Performance (VHEP) fed-batch process under anaerobic conditions. Both strains showed a drastic reduction of the glycerol yield by 44 and 61% while the ethanol yield improved by 2 and 7% respectively. TEFmut2 strain showing the highest ethanol yield was accompanied by a 28% reduction of the biomass yield. The modulation of the glycerol formation led to profound redox and energetic changes resulting in a reduction of the ATP yield (YATP) and a modulation of the production of organic acids (acetate, pyruvate and succinate). Those metabolic rearrangements resulted in a loss of ethanol and stress tolerance of the mutants, contrarily to what was previously observed under aerobiosis. This work demonstrates the potential of fine-tuned pathway engineering, particularly when a compromise has to be found between high product yield on one hand and acceptable growth, productivity and stress resistance on the other hand. Previous study showed that, contrarily to anaerobiosis, the resulting gain in ethanol yield was accompanied with no loss of ethanol tolerance under aerobiosis. Moreover those mutants were still able to produce up to 90 gl-1 ethanol in an anaerobic SSF process. Fine tuning metabolic strategy may then open encouraging possibilities for further developing robust strains with improved ethanol yield.

Significant promotion effect of carbon nanotubes on the electrocatalytic activity of supported Pd NPs for ethanol oxidation reaction of fuel cells: the role of inner tubes.

PubMed

Zhang, Jin; Cheng, Yi; Lu, Shanfu; Jia, Lichao; Shen, Pei Kang; Jiang, San Ping

2014-11-18

The inner tubes of carbon nanotubes (CNTs) have a significant promotion effect on the electrocatalytic activity of Pd nanoparticles (NPs) for the ethanol oxidation of direct alcohol fuel cells (DAFCs) and Pd NPs supported on CNTs with 3-7 walls show a much higher activity as compared to that supported on typical single-walled and multi-walled CNTs.

PdCo porous nanostructures decorated on polypyrrole @ MWCNTs conductive nanocomposite-Modified glassy carbon electrode as a powerful catalyst for ethanol electrooxidation

NASA Astrophysics Data System (ADS)

Fard, Leyla Abolghasemi; Ojani, Reza; Raoof, Jahan Bakhsh; Zare, Ehsan Nazarzadeh; Lakouraj, Moslem Mansour

2017-04-01

In the current study, well-defined PdCo porous nanostructure (PdCo PNS) is prepared by a simple one-pot wet-chemical method and polypyrrole@multi-walled carbon nanotubes (PPy@MWCNTs) nanocomposite is used as a catalyst support. The morphology and the structural properties of the prepared catalyst were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The electrocatalytic performance of PdCo PNS/PPy@MWCNTs on glassy carbon electrode has been evaluated by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) techniques. The specific activity of PdCo PNS/PPy@MWCNTs for ethanol electrooxidation (1.65 mA cm-2) is higher than those of other compared electrocatalysts. Also, PdCo PNS/PPy@MWCNTs catalyst represented higher electrocatalytic activity, better long-term stability and high level of poisoning tolerance to the carbonaceous oxidative intermediates for ethanol electrooxidation reaction in alkaline media. Furthermore, the presence of PPY@MWCNTs on the surface of GCE produce a high activity to electrocatalyst, which might be due to the easier charge transfer at polymer/carbon nanotubes interfaces, higher electrochemically accessible surface areas and electronic conductivity. The superior catalytic activity of PdCo PNS/PPy@MWCNTs suggests it to be as a promising electrocatalyst for future direct ethanol fuel cells.

Diversity and Fermentation Products of Xylose-Utilizing Yeasts Isolated from Buffalo Feces in Thailand

PubMed Central

Lorliam, Wanlapa; Akaracharanya, Ancharida; Suzuki, Motofumi; Ohkuma, Moriya; Tanasupawat, Somboon

2013-01-01

Twenty-eight xylose-utilizing yeast strains were isolated by enrichment culture from 11 samples of feces from the rectum of Murrah buffalo and Swamp buffalo in Thailand. On the basis of their morphological and biochemical characteristics, including sequence analysis of the D1/D2 region of the large-subunit ribosomal RNA gene (LSU rDNA), they were identified as Candida tropicalis (designated as Group I, 11 isolates), Candida parasilosis (Group II, 2 isolates), Candida mengyuniae (Group III, 2 isolates), Sporopachydermia lactativora (Group IV, 2 isolates), Geotrichum sp. (Group V, 5 isolates) and Trichosporon asahii (Group VI, 6 isolates). All isolates utilized xylose as the sole carbon source but 27 isolates could ferment xylose to ethanol (0.006–0.602 g L−1) and 21 isolates could ferment xylose to xylitol (0.19–22.84 g L−1). Candida tropicalis isolates produced the highest yield of xylitol (74.80%). Their ability to convert xylose to xylitol and ethanol ranged from 15.06 g L−1 to 22.84 g L−1 xylitol and 0.110 g L−1 to 0.602 g L−1 ethanol, respectively. PMID:24005843

Deletion of the Glucose-6-Phosphate Dehydrogenase Gene KlZWF1 Affects both Fermentative and Respiratory Metabolism in Kluyveromyces lactis▿

PubMed Central

Saliola, Michele; Scappucci, Gina; De Maria, Ilaria; Lodi, Tiziana; Mancini, Patrizia; Falcone, Claudio

2007-01-01

In Kluyveromyces lactis, the pentose phosphate pathway is an alternative route for the dissimilation of glucose. The first enzyme of the pathway is the glucose-6-phosphate dehydrogenase (G6PDH), encoded by KlZWF1. We isolated this gene and examined its role. Like ZWF1 of Saccharomyces cerevisiae, KlZWF1 was constitutively expressed, and its deletion led to increased sensitivity to hydrogen peroxide on glucose, but unlike the case for S. cerevisiae, the Klzwf1Δ strain had a reduced biomass yield on fermentative carbon sources as well as on lactate and glycerol. In addition, the reduced yield on glucose was associated with low ethanol production and decreased oxygen consumption, indicating that this gene is required for both fermentation and respiration. On ethanol, however, the mutant showed an increased biomass yield. Moreover, on this substrate, wild-type cells showed an additional band of activity that might correspond to a dimeric form of G6PDH. The partial dimerization of the G6PDH tetramer on ethanol suggested the production of an NADPH excess that was negative for biomass yield. PMID:17085636

Production of raw cassava starch-degrading enzyme by Penicillium and its use in conversion of raw cassava flour to ethanol.

PubMed

Lin, Hai-Juan; Xian, Liang; Zhang, Qiu-Jiang; Luo, Xue-Mei; Xu, Qiang-Sheng; Yang, Qi; Duan, Cheng-Jie; Liu, Jun-Liang; Tang, Ji-Liang; Feng, Jia-Xun

2011-06-01

A newly isolated strain Penicillium sp. GXU20 produced a raw starch-degrading enzyme which showed optimum activity towards raw cassava starch at pH 4.5 and 50 °C. Maximum raw cassava starch-degrading enzyme (RCSDE) activity of 20 U/ml was achieved when GXU20 was cultivated under optimized conditions using wheat bran (3.0% w/v) and soybean meal (2.5% w/v) as carbon and nitrogen sources at pH 5.0 and 28 °C. This represented about a sixfold increment as compared with the activity obtained under basal conditions. Starch hydrolysis degree of 95% of raw cassava flour (150 g/l) was achieved after 72 h of digestion by crude RCSDE (30 U/g flour). Ethanol yield reached 53.3 g/l with fermentation efficiency of 92% after 48 h of simultaneous saccharification and fermentation of raw cassava flour at 150 g/l using the RCSDE (30 U/g flour), carried out at pH 4.0 and 40 °C. This strain and its RCSDE have potential applications in processing of raw cassava starch to ethanol.

Renewable energy from biomass: a sustainable option? - Hydrogen production from alcohols

NASA Astrophysics Data System (ADS)

Balla, Zoltán; Kith, Károly; Tamás, András; Nagy, Orsolya

2015-04-01

Sustainable development requires us to find new energy sources instead of fossil fuels. One possibility is the hydrogen fuel cell, which uses significantly more efficient than the current combustion engines. The task of the hydrogen is clean, carbon-free renewable energy sources to choose in the future by growing degree. Hungary can play a role in the renewable energy sources of biomass as a renewable biomass annually mass of about 350 to 360 million tons. The biomass is only a very small proportion of fossil turn carbonaceous materials substitution, while we may utilize alternative energy sources as well. To the hydrogen production from biomass, the first step of the chemical transformations of chemical bonds are broken, which is always activation energy investment needs. The methanol and ethanol by fermentation from different agricultural products is relatively easy to produce, so these can be regarded as renewable energy carriers of. The ethanol can be used directly, and used in several places in the world are mixed with the petrol additive. This method is the disadvantage that the anhydrous alcohol is to be used in the combustion process in the engine more undesired by-products may be formed, and the fuel efficiency of the engine is significantly lower than the efficiency of the fuel cells. More useful to produce hydrogen from the alcohol and is used in a fuel cell electric power generation. Particularly attractive option for the so-called on-board reforming of alcohols, that happens immediately when the vehicle hydrogen production. It does not need a large tank of hydrogen, because the hydrogen produced would be directly to the fuel cell. The H2 tank limit use of its high cost, the significant loss evaporation, the rare-station network, production capacity and service background and lack of opportunity to refuel problems. These can be overcome, if the hydrogen in the vehicle is prepared. As volume even 700 bar only about half the H2 pressure gas can be stored in the case, than the same volume of ethanol-water mixture can be prepared. The renewal of alcohol, the alcohol-water mixture is then passed through the catalytic reformer into a preheater. The exhaust gas contains a relatively large number of carbon monoxide, which would spoil the fuel cell, so the carbon monoxide concentration to a high and a low temperature water-gas reaction is reduced. This increases the hydrogen production. The last step of the carbon monoxide content to eliminate preferential oxidation. The alcohol reforming catalyst for the precious metals spread most of what arose from high activity and stability. However, the precious metals are very expensive, so a non-precious metal catalysts is the design and development of objective activity and stability which reaches the precious metal catalysts of. Using the new reaction catalysts opportunities are created, which are smaller than the activation energy than the non-catalytic process. The basic objective of the technological developments more active at lower temperatures, the selective target product, long-life, low cost design catalysts.

Integrating biorefinery and farm biogeochemical cycles offsets fossil energy and mitigates soil carbon losses.

PubMed

Adler, Paul R; Mitchell, James G; Pourhashem, Ghasideh; Spatari, Sabrina; Del Grosso, Stephen J; Parton, William J

2015-06-01

Crop residues are potentially significant sources of feedstock for biofuel production in the United States. However, there are concerns with maintaining the environmental functions of these residues while also serving as a feedstock for biofuel production. Maintaining soil organic carbon (SOC) along with its functional benefits is considered a greater constraint than maintaining soil erosion losses to an acceptable level. We used the biogeochemical model DayCent to evaluate the effect of residue removal, corn stover, and wheat and barley straw in three diverse locations in the USA. We evaluated residue removal with and without N replacement, along with application of a high-lignin fermentation byproduct (HLFB), the residue by-product comprised of lignin and small quantities of nutrients from cellulosic ethanol production. SOC always decreased with residue harvest, but the decrease was greater in colder climates when expressed on a life cycle basis. The effect of residue harvest on soil N2O emissions varied with N addition and climate. With N addition, N2O emissions always increased, but the increase was greater in colder climates. Without N addition, N2O emissions increased in Iowa, but decreased in Maryland and North Carolina with crop residue harvest. Although SOC was lower with residue harvest when HLFB was used for power production instead of being applied to land, the avoidance of fossil fuel emissions to the atmosphere by utilizing the cellulose and hemicellulose fractions of crop residue to produce ethanol (offsets) reduced the overall greenhouse gas (GHG) emissions because most of this residue carbon would normally be lost during microbial respiration. Losses of SOC and reduced N mineralization could both be mitigated with the application of HLFB to the land. Therefore, by returning the high-lignin fraction of crop residue to the land after production of ethanol at the biorefinery, soil carbon levels could be maintained along with the functional benefit of increased mineralized N, and more GHG emissions could be offset compared to leaving the crop residues on the land.

Comparison of the Anti-Inflammatory Activities of Supercritical Carbon Dioxide versus Ethanol Extracts from Leaves of Perilla frutescens Britt. Radiation Mutant.

PubMed

Jin, Chang Hyun; Park, Han Chul; So, Yangkang; Nam, Bomi; Han, Sung Nim; Kim, Jin-Baek

2017-02-17

In this study, we aimed to compare supercritical carbon dioxide extraction and ethanol extraction for isoegomaketone (IK) content in perilla leaf extracts and to identify the optimal method. We measured the IK concentration using HPLC and inflammatory mediators in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells from the extracts. The IK concentration was 10-fold higher in perilla leaf extracts by supercritical carbon dioxide extraction (SFE) compared with that in perilla leaf extracts by ethanol extraction (EE). When the extracts were treated in LPS-induced RAW 264.7 cells at 25 μg/mL, the SFE inhibited the expression of inflammatory mediators such as nitric oxide (NO), monocyte chemoattractant protein-1 (MCP-1), interleutkin-6 (IL-6), interferon-β (IFN-β), and inducible nitric oxide synthase (iNOS) to a much greater extent compared with EE. Taken together, supercritical carbon dioxide extraction is considered the optimal process for obtaining high IK content and anti-inflammatory activities in leaf extracts from the P. frutescens Britt. radiation mutant.

Activity Tests of Macro-Meso Porous Catalysts over Metal Foam Plate for Steam Reforming of Bio-Ethanol.

PubMed

Park, No-Kuk; Jeong, Yong Han; Kang, Misook; Lee, Tae Jin

2018-09-01

The catalytic activity of a macro-mesoporous catalyst coated on a metal foam plate in the reforming of bio-ethanol to synthesis gas was investigated. The catalysts were prepared by coating a support with a noble metal and transition metal. The catalytic activity for the production of synthetic gas by the reforming of bio-ethanol was compared according to the support material, reaction temperature, and steam/carbon ratio. The catalysts coated on the metal foams were prepared using a template method, in which macro-pores and meso-pores were formed by mixing polymer beads. In particular, the thermodynamic equilibrium composition of bio-ethanol reforming with the reaction temperature and steam/carbon ratio to produce synthetic gas was examined using the HSC (Enthalpy-Entropy-Heat capacity) chemistry program in this study. The composition of hydrogen and carbon monoxide in the reformate gas produced by steam reforming over the Rh/Ni-Ce-Zr/Al2O3-based pellet type catalysts and metal foam catalysts that had been coated with the Rh/Al-Ce-Zr-based catalysts was investigated by experimental activity tests. The activity of the metal foam catalyst was higher than that of the pellet type catalyst.

Nitrogen Sources Screening for Ethanol Production Using Carob Industrial Wastes.

PubMed

Raposo, S; Constantino, A; Rodrigues, F; Rodrigues, B; Lima-Costa, M E

2017-02-01

Nowadays, bioethanol production is one of the most important technologies by the necessity to identify alternative energy resources, principally when based on inexpensive renewable resources. However, the costs of 2nd-generation bioethanol production using current biotechnologies are still high compared to fossil fuels. The feasibility of bioethanol production, by obtaining high yields and concentrations of ethanol, using low-cost medium, is the primary goal, leading the research done today. Batch Saccharomyces cerevisiae fermentation of high-density sugar from carob residues with different organic (yeast extract, peptone, urea) and inorganic nitrogen sources (ammonium sulfate, ammonium nitrate) was performed for evaluating a cost-effective ethanol production, with high ethanol yield and productivity. In STR batch fermentation, urea has proved to be a very promising nitrogen source in large-scale production of bioethanol, reaching an ethanol yield of 44 % (w/w), close to theoretical maximum yield value and an ethanol production of 115 g/l. Urea at 3 g/l as nitrogen source could be an economical alternative with a great advantage in the sustainability of ethanol production from carbohydrates extracted from carob. Simulation studies, with experimental data using SuperPro Design software, have shown that the bioethanol production biorefinery from carob wastes could be a very promising way to the valorization of an endogenous resource, with a competitive cost.

Water-assisted growth of graphene on carbon nanotubes by the chemical vapor deposition method.

PubMed

Feng, Jian-Min; Dai, Ye-Jing

2013-05-21

Combining carbon nanotubes (CNTs) with graphene has been proved to be a feasible method for improving the performance of graphene for some practical applications. This paper reports a water-assisted route to grow graphene on CNTs from ferrocene and thiophene dissolved in ethanol by the chemical vapor deposition method in an argon flow. A double injection technique was used to separately inject ethanol solution and water for the preparation of graphene/CNTs. First, CNTs were prepared from ethanol solution and water. The injection of ethanol solution was suspended and water alone was injected into the reactor to etch the CNTs. Thereafter, ethanol solution was injected along with water, which is the key factor in obtaining graphene/CNTs. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and Raman scattering analyses confirmed that the products were the hybrid materials of graphene/CNTs. X-ray photo-electron spectroscopy analysis showed the presence of oxygen rich functional groups on the surface of the graphene/CNTs. Given the activity of the graphene/CNT surface, CdS quantum dots adhered onto it uniformly through simple mechanical mixing.

Solvent-induced synthesis of nitrogen-doped hollow carbon spheres with tunable surface morphology for supercapacitors

NASA Astrophysics Data System (ADS)

Liu, Feng; Yuan, Ren-Lu; Zhang, Ning; Ke, Chang-Ce; Ma, Shao-Xia; Zhang, Ru-Liang; Liu, Lei

2018-04-01

Nitrogen doped hollow carbon spheres (NHCSs) with tunable surface morphology have been prepared through one-pot carbonization method by using melamine-formaldehyde spheres as template and resorcinol-based resin as carbon precursor in ethanol-water solution. Well-dispersed NHCSs with particle size of 800 nm were obtained and the surface of NHCSs turn from smooth to tough, wrinkled, and finally concave by increasing the ethanol concentration. The fabricated NHCSs possessed high nitrogen content (3.99-4.83%) and hierarchical micro-dual mesoporous structure with surface area range of 265-405 m2 g-1 and total pore volume of 0.18-0.29 cm3 g-1, which contributed to high specific capacitance, excellent rate capability and long cycle life.

Elimination of hydrogenase active site assembly blocks H2 production and increases ethanol yield in Clostridium thermocellum

DOE PAGES

Biswas, Ranjita; Zheng, Tianyong; Olson, Daniel G.; ...

2015-02-12

The native ability of Clostridium thermocellum to rapidly consume cellulose and produce ethanol makes it a leading candidate for a consolidated bioprocessing (CBP) biofuel production strategy. C. thermocellum also synthesizes lactate, formate, acetate, H2, and amino acids that compete with ethanol production for carbon and electrons. Elimination of H2 production could redirect carbon flux towards ethanol production by making more electrons available for acetyl-CoA reduction to ethanol. C. thermocellum encodes four hydrogenases and rather than delete each individually, we targeted a hydrogenase maturase gene (hydG), involved in converting the three [FeFe] hydrogenase apoenzymes into holoenzymes. Further deletion of the [NiFe]more » hydrogenase (ech) resulted in a mutant that functionally lacks all four hydrogenases. H2 production in hydG ech was undetectable and ethanol yield increased nearly 2-fold compared to wild type. Interestingly, mutant growth improved upon the addition of acetate, which led to increased expression of genes related to sulfate metabolism, suggesting these mutants may use sulfate as a terminal electron acceptor to balance redox reactions. Genomic analysis of hydG revealed a mutation in adhE, resulting in a strain with both NADH- and NADPH-dependent alcohol dehydrogenase activities. While this same adhE mutation is found in ethanol tolerant C. thermocellum strain E50C, hydG and hydG ech are not more ethanol tolerant than wild type, illustrating the complicated interactions between redox balancing and ethanol tolerance in C. thermocellum. The dramatic increase in ethanol production here suggests that targeting protein post-translational modification is a promising new approach for inactivation of multiple enzymes simultaneously for metabolic engineering.« less

Screening of natural yeast isolates under the effects of stresses associated with second-generation biofuel production.

PubMed

Dubey, Rajni; Jakeer, Shaik; Gaur, Naseem A

2016-05-01

Robust microorganisms are required for sustainable second-generation biofuel production. We evaluated the growth and fermentation performance of six natural isolates that were derived from grape wine and medicinal herbs using a wide range of carbon sources, rice and wheat straw hydrolysates as well as stress conditions associated with second-generation ethanol production. Sequence analysis of the 5.8S internal transcribed spacer (ITS) and species-specific PCR amplification of the HO gene region assigned the natural isolates to Saccharomyces cerevisiae. Restriction fragment length polymorphism (RFLP) analysis of the mitochondrial DNA revealed that natural yeast isolates are genetically closer to the laboratory strain BY4741 than to the CEN.PK strains. Dextrose fermentation by a natural isolate, MTCC4780, under semi-anaerobic conditions produced maximum ethanol yields of 0.44 g/g and 0.39 g/g, respectively, with and without the stresses encountered during lignocellulosic ethanol fermentation. However, MTCC4780 produced ethanol yields of 0.48 g/g, 0.42 g/g and 0.45 g/g, respectively, with glucose, rice and wheat straw enzymatic hydrolysate fermentation in a bioreactor. The isolates MTCC4781 and MTCC4796 showed higher growth and fermentation performance than did MTCC4780 in the presence of elevated temperature and pre-treatment inhibitors. Taken together, the MTCC4780, MTCC4781 and MTCC4796 strains have the potential to serve as a platform for lignocellulosic ethanol production under stresses associated with second-generation biofuel production. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Potential feedstock sources for ethanol production in Florida

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rahmani, Mohammad; Hodges, Alan

This study presents information on the potential feedstock sources that may be used for ethanol production in Florida. Several potential feedstocks for fuel ethanol production in Florida are discussed, such as, sugarcane, corn, citrus byproducts and sweet sorghum. Other probable impacts need to be analyzed for sugarcane to ethanol production as alternative uses of sugarcane may affect the quantity of sugar production in Florida. While citrus molasses is converted to ethanol as an established process, the cost of ethanol is higher, and the total amount of citrus molasses per year is insignificant. Sorghum cultivars have the potential for ethanol production.more » However, the agricultural practices for growing sweet sorghum for ethanol have not been established, and the conversion process must be tested and developed at a more expanded level. So far, only corn shipped from other states to Florida has been considered for ethanol production on a commercial scale. The economic feasibility of each of these crops requires further data and technical analysis.« less

Nanostructured carbon-supported Pd electrocatalysts for ethanol oxidation: synthesis and characterization

NASA Astrophysics Data System (ADS)

Gacutan, E. M.; Climaco, M. I.; Telan, G. J.; Malijan, F.; Hsu, H. Y.; Garcia, J.; Fulo, H.; Tongol, B. J.

2012-12-01

The need to lower the construction cost of fuel cells calls for the development of non-Pt based electrocatalysts. Among others, Pd has emerged as a promising alternative to Pt for fuel cell catalysis. This research aims to investigate the synthesis and characterization of nanostructured Pd-based catalysts dispersed on carbon support as anode materials in direct ethanol fuel cells. For the preparation of the first Pd-based electrocatalyst, palladium nanoparticles (NPs) were synthesized via oleylamine (OAm)-mediated synthesis and precursor method with a mean particle size of 3.63 ± 0.59 nm as revealed by transmission electron microscopy (TEM). Carbon black was used as a supporting matrix for the OAm-capped Pd NPs. Thermal annealing and acetic acid washing were used to remove the OAm capping agent. To evaluate the electrocatalytic activity of the prepared electrocatalyst towards ethanol oxidation, cyclic voltammetry (CV) studies were performed using 1.0 M ethanol in basic medium. The CV data revealed the highest peak current density of 11.05 mA cm-2 for the acetic acid-washed Pd/C electrocatalyst. Meanwhile, the fabrication of the second Pd-based electrocatalyst was done by functionalization of the carbon black support using 3:1 (v/v) H2SO4:HNO3. The metal oxide, NiO, was deposited using precipitation method while polyol method was used for the deposition of Pd NPs. X-ray diffraction (XRD) analysis revealed that the estimated particle size of the synthesized catalysts was at around 9.0-15.0 nm. CV results demonstrated a 36.7% increase in the catalytic activity of Pd-NiO/C (functionalized) catalyst towards ethanol oxidation compared to the non-functionalized catalyst.

Recent trends in bioethanol production from food processing byproducts.

PubMed

Akbas, Meltem Yesilcimen; Stark, Benjamin C

2016-11-01

The widespread use of corn starch and sugarcane as sources of sugar for the production of ethanol via fermentation may negatively impact the use of farmland for production of food. Thus, alternative sources of fermentable sugars, particularly from lignocellulosic sources, have been extensively investigated. Another source of fermentable sugars with substantial potential for ethanol production is the waste from the food growing and processing industry. Reviewed here is the use of waste from potato processing, molasses from processing of sugar beets into sugar, whey from cheese production, byproducts of rice and coffee bean processing, and other food processing wastes as sugar sources for fermentation to ethanol. Specific topics discussed include the organisms used for fermentation, strategies, such as co-culturing and cell immobilization, used to improve the fermentation process, and the use of genetic engineering to improve the performance of ethanol producing fermenters.

Investigation of utilization of the algal biomass residue after oil extraction to lower the total production cost of biodiesel.

PubMed

Gao, Min-Tian; Shimamura, Takashi; Ishida, Nobuhiro; Takahashi, Haruo

2012-09-01

In this study, component analysis of a novel biodiesel-producing alga, Pseudochoricystis ellipsoidea, was performed. The component analysis results indicated that proteins and amino acids are abundant in P. ellipsoidea while the sugar content is relatively low. Rather than its use as a carbon source, the use of the algal biomass residue after oil extraction as a nutrient source provided a new way for lowering the total production cost of biodiesel. In both lactic acid and ethanol fermentations, the use of the residue instead of high-cost nutrient yeast extract allowed a significant saving, showing the promise of the algal biomass residue for use as a fermentation nutrient source. Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Neuroprotective effect of ethanol in acute carbon monoxide intoxication: A retrospective study.

PubMed

Kim, Hyuk-Hoon; Choi, Sang Chun; Chae, Minjung Kathy; Min, Young-Gi

2018-01-01

In acute carbon monoxide (CO) intoxication, treatment of neurologic injury and prevention of neurological sequelae are primary concerns. Ethanol is the one of the frequent substances which is co-ingested in intentional CO poisoning. Neuroprotective effect of ethanol was highlighted and demonstrated in isolated brain injury recently. We assessed the neuroprotective effect of ethanol in acute CO intoxication using magnetic resonance imaging (MRI).We retrospectively reviewed medical records for patients who visited an emergency medical center of a university-affiliated hospital during a period of 73 months, from March 2009 to April 2015. Enrolled patients were divided into 2 groups, patients with or without abnormal brain lesion in brain MRI. Multivariate logistic regression analysis was performed to assess the factors associated with brain injury in MRI.A total of 109 patients with acute CO intoxication were evaluated of which 66 (60.55%) tested positive in brain MRI. MRI lesion-positive patients were more likely to have electrocardiogram change, elevation of serum troponin I and s100 protein level and lower serum ethanol level. Serum ethanol positivity was an independent factor for prevalence of brain injury in MRI in acute CO poisoning.This study revealed that ethanol which is co-ingested in acute CO intoxication may work the neuroprotective effect and could consequence more favorable neurological outcome in acute CO intoxication. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

Sinusoidal potential cycling operation of a direct ethanol fuel cell to improving carbon dioxide yields

NASA Astrophysics Data System (ADS)

Majidi, Pasha; Pickup, Peter G.

2014-12-01

A direct ethanol fuel cell has been operated under sinusoidal (AC) potential cycling conditions in order to increase the yield of carbon dioxide and thereby increase cell efficiency relative to operation at a fixed potential. At 80 °C, faradaic yields of CO2 as high as 25% have been achieved with a PtRu anode catalyst, while the maximum CO2 production at constant potential was 13%. The increased yields under cycling conditions have been attributed to periodic oxidative stripping of adsorbed CO. These results will be important in the optimization of operating conditions for direct ethanol fuel cells, where the benefits of potential cycling are projected to increase as catalysts that produce CO2 more efficiently are implemented.

Palladium-cobalt nanotube arrays supported on carbon fiber cloth as high-performance flexible electrocatalysts for ethanol oxidation.

PubMed

Wang, An-Liang; He, Xu-Jun; Lu, Xue-Feng; Xu, Han; Tong, Ye-Xiang; Li, Gao-Ren

2015-03-16

PdCo nanotube arrays (NTAs) supported on carbon fiber cloth (CFC) (PdCo NTAs/CFC) are presented as high-performance flexible electrocatalysts for ethanol oxidation. The fabricated flexible PdCo NTAs/CFC exhibits significantly improved electrocatalytic activity and durability compared with Pd NTAs/CFC and commercial Pd/C catalysts. Most importantly, the PdCo NTAs/CFC shows excellent flexibility and the high electrocatalytic performance remains almost constant under the different distorted states, such as normal, bending, and twisting states. This work shows the first example of Pd-based alloy NTAs supported on CFC as high-performance flexible electrocatalysts for ethanol oxidation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ethanol and Methanol Can Improve Huperzine A Production from Endophytic Colletotrichum gloeosporioides ES026

PubMed Central

Zhao, Xin-Mei; Wang, Zhang-Qian; Shu, Shao-Hua; Wang, Wen-Juan; Xu, Hai-Jie; Ahn, Young-Joon; Wang, Mo; Hu, Xuebo

2013-01-01

Huperzine A (HupA) is a plant alkaloid that is of great interest as a therapeutic candidate for the treatment of Alzheimer's disease. However, the current production of HupA from plants in large quantity is unsustainable because the plant resource is scarce and the content of HupA in plants is extremely low. Surprisingly, this compound was recently found to be produced by various endophytic fungi, which are much more controllable than the plants due to simpler genetics and ease of manipulation. However, it might be due to the innate properties of endophytic symbiosis, that production of this chemical in large quantity from endophytes has not yet been put into practice. Endophytic Colletotrichum gloeosporioides ES026 was previously isolated from a HupA producing plant and the fungi also proved to produce HupA. In this study, various fermentation conditions were tried to optimize the production of HupA from C. gloeosporioides ES026. Optimization of these parameters resulted in a 25.58% increase in HupA yield. Potato extracts supplemented with glucose or sucrose but not maltose facilitated HupA producing from the fungi. A final concentration of 0.5–2% ethanol stimulated the growth of fungi while methanol with the same treatment slightly inhibited the growth. However, both methanol and ethanol greatly increased the HupA production with the highest yield of HupA (51.89% increment) coming from ethanol treatment. Further analysis showed that both ethanol and methanol were strong inducers of HupA production, while ethanol was partially used as a carbon source during fermentation. It was noticed that the color of that ethanol treated mycelia gradually became dark while methanol treated ones stayed grey during fermentation. The present study sheds light on the importance of optimizing the fermentation process, which, combined with effective inducers, maximizes production of chemicals of important economic interest from endophytic fungi. PMID:23613930

In situ hydrogen, acetone, butanol, ethanol and microdiesel production by Clostridium acetobutylicum ATCC 824 from oleaginous fungal biomass.

PubMed

Hassan, Elhagag Ahmed; Abd-Alla, Mohamed Hemida; Bagy, Magdy Mohamed Khalil; Morsy, Fatthy Mohamed

2015-08-01

An in situ batch fermentation technique was employed for biohydrogen, acetone, butanol, ethanol and microdiesel production from oleaginous fungal biomass using the anaerobic fermentative bacterium Clostridium acetobutylicum ATCC 824. Oleaginous fungal Cunninghamella echinulata biomass which has ability to accumulate up to 71% cellular lipid was used as the substrate carbon source. The maximum cumulative hydrogen by C. acetobutylicum ATCC 824 from crude C. echinulata biomass was 260 ml H2 l(-1), hydrogen production efficiency was 0.32 mol H2 mole(-1) glucose and the hydrogen production rate was 5.2 ml H2 h(-1). Subsequently, the produced acids (acetic and butyric acids) during acidogenesis phase are re-utilized by ABE-producing clostridia and converted into acetone, butanol, and ethanol. The total ABE produced by C. acetobutylicum ATCC 824 during batch fermentation was 3.6 g l(-1) from crude fungal biomass including acetone (1.05 g l(-1)), butanol (2.19 g l(-1)) and ethanol (0.36 g l(-1)). C. acetobutylicum ATCC 824 has ability to produce lipolytic enzymes with a specific activity 5.59 U/mg protein to hydrolyze ester containing substrates. The lipolytic potential of C. acetobutylicum ATCC 824 was used as a biocatalyst for a lipase transesterification process using the produced ethanol from ABE fermentation for microdiesel production. The fatty acid ethyl esters (microdiesel) generated from the lipase transesterification of crude C. echinulata dry mass was analyzed by GC/MS as 15.4% of total FAEEs. The gross energy content of biohydrogen, acetone, butanol, ethanol and biodiesel generated through C. acetobutylicum fermentation from crude C. echinulata dry mass was 3113.14 kJ mol(-1). These results suggest a possibility of integrating biohydrogen, acetone, butanol and ethanol production technology by C. acetobutylicum with microdiesel production from crude C. echinulata dry mass and therefore improve the feasibility and commercialization of bioenergy production. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ethanol and methanol can improve huperzine A production from endophytic Colletotrichum gloeosporioides ES026.

PubMed

Zhao, Xin-Mei; Wang, Zhang-Qian; Shu, Shao-Hua; Wang, Wen-Juan; Xu, Hai-Jie; Ahn, Young-Joon; Wang, Mo; Hu, Xuebo

2013-01-01

Huperzine A (HupA) is a plant alkaloid that is of great interest as a therapeutic candidate for the treatment of Alzheimer's disease. However, the current production of HupA from plants in large quantity is unsustainable because the plant resource is scarce and the content of HupA in plants is extremely low. Surprisingly, this compound was recently found to be produced by various endophytic fungi, which are much more controllable than the plants due to simpler genetics and ease of manipulation. However, it might be due to the innate properties of endophytic symbiosis, that production of this chemical in large quantity from endophytes has not yet been put into practice. Endophytic Colletotrichum gloeosporioides ES026 was previously isolated from a HupA producing plant and the fungi also proved to produce HupA. In this study, various fermentation conditions were tried to optimize the production of HupA from C. gloeosporioides ES026. Optimization of these parameters resulted in a 25.58% increase in HupA yield. Potato extracts supplemented with glucose or sucrose but not maltose facilitated HupA producing from the fungi. A final concentration of 0.5-2% ethanol stimulated the growth of fungi while methanol with the same treatment slightly inhibited the growth. However, both methanol and ethanol greatly increased the HupA production with the highest yield of HupA (51.89% increment) coming from ethanol treatment. Further analysis showed that both ethanol and methanol were strong inducers of HupA production, while ethanol was partially used as a carbon source during fermentation. It was noticed that the color of that ethanol treated mycelia gradually became dark while methanol treated ones stayed grey during fermentation. The present study sheds light on the importance of optimizing the fermentation process, which, combined with effective inducers, maximizes production of chemicals of important economic interest from endophytic fungi.

Ethanolic carbon-11 chemistry: the introduction of green radiochemistry.

PubMed

Shao, Xia; Fawaz, Maria V; Jang, Keunsam; Scott, Peter J H

2014-07-01

The principles of green chemistry have been applied to a radiochemistry setting. Eleven carbon-11 labeled radiopharmaceuticals have been prepared using ethanol as the only organic solvent throughout the entire manufacturing process. The removal of all other organic solvents from the process simplifies production and quality control (QC) testing, moving our PET Center towards the first example of a green radiochemistry laboratory. All radiopharmaceutical doses prepared are suitable for clinical use. Copyright © 2014 Elsevier Ltd. All rights reserved.

Nitrogen-Doped Carbon Nanotube-Supported Pd Catalyst for Improved Electrocatalytic Performance toward Ethanol Electrooxidation

NASA Astrophysics Data System (ADS)

Wei, Ying; Zhang, Xinyuan; Luo, Zhiyong; Tang, Dian; Chen, Changxin; Zhang, Teng; Xie, Zailai

2017-07-01

In this study, hydrothermal carbonization (HTC) was applied for surface functionalization of carbon nanotubes (CNTs) in the presence of glucose and urea. The HTC process allowed the deposition of thin nitrogen-doped carbon layers on the surface of the CNTs. By controlling the ratio of glucose to urea, nitrogen contents of up to 1.7 wt% were achieved. The nitrogen-doped carbon nanotube-supported Pd catalysts exhibited superior electrochemical activity for ethanol oxidation relative to the pristine CNTs. Importantly, a 1.5-fold increase in the specific activity was observed for the Pd/HTC-N1.67%CNTs relative to the catalyst without nitrogen doping (Pd/HTC-CNTs). Further experiments indicated that the introduction of nitrogen species on the surface of the CNTs improved the Pd(0) loading and increased the binding energy.

Engineering of the redox imbalance of Fusarium oxysporum enables anaerobic growth on xylose.

PubMed

Panagiotou, Gianni; Christakopoulos, Paul; Grotkjaer, Thomas; Olsson, Lisbeth

2006-09-01

Dissimilatory nitrate reduction metabolism, of the natural xylose-fermenting fungus Fusarium oxysporum, was used as a strategy to achieve anaerobic growth and ethanol production from xylose. Beneficial alterations of the redox fluxes and thereby of the xylose metabolism were obtained by taking advantage of the regeneration of the cofactor NAD(+) during the denitrification process. In batch cultivations, nitrate sustained growth under anaerobic conditions (1.21 g L(-1) biomass) and simultaneously a maximum yield of 0.55 moles of ethanol per mole of xylose was achieved, whereas substitution of nitrate with ammonium limited the growth significantly (0.15 g L(-1) biomass). Using nitrate, the maximum acetate yield was 0.21 moles per mole of xylose and no xylitol excretion was observed. Furthermore, the network structure in the central carbon metabolism of F. oxysporum was characterized in steady state. F. oxysporum grew anaerobically on [1-(13)C] labelled glucose and unlabelled xylose in chemostat cultivation with nitrate as nitrogen source. The use of labelled substrate allowed the precise determination of the glucose and xylose contribution to the carbon fluxes in the central metabolism of this poorly described microorganism. It was demonstrated that dissimilatory nitrate reduction allows F. oxysporum to exhibit typical respiratory metabolic behaviour with a highly active TCA cycle and a large demand for NADPH.

Using natural biomass microorganisms for drinking water denitrification.

PubMed

Costa, Darleila Damasceno; Gomes, Anderson Albino; Fernandes, Mylena; Lopes da Costa Bortoluzzi, Roseli; Magalhães, Maria de Lourdes Borba; Skoronski, Everton

2018-07-01

Among the methods that are studied to eliminate nitrate from drinking water, biological denitrification is an attractive strategy. Although several studies report the use of denitrifying bacteria for nitrate removal, they usually involve the use of sewage sludge as biomass to obtain the microbiota. In the present study, denitrifying bacteria was isolated from bamboo, and variable parameters were controlled focusing on optimal bacterial performance followed by physicochemical analysis of water adequacy. In this way, bamboo was used as a source of denitrifying microorganisms, using either Immobilized Microorganisms (IM) or Suspended Microorganisms (SM) for nitrate removal. Denitrification parameters optimization was carried out by analysis of denitrification at different pH values, temperature, nitrate concentrations, carbon sources as well as different C/N ratios. In addition, operational stability and denitrification kinetics were evaluated. Microorganisms present in the biomass responsible for denitrification were identified as Proteus mirabilis. The denitrified water was submitted to physicochemical treatment such as coagulation and flocculation to adjust to the parameters of color and turbidity to drinking water standards. Denitrification using IM occurred with 73% efficiency in the absence of an external carbon source. The use of SM provided superior denitrification efficiency using ethanol (96.46%), glucose (98.58%) or glycerol (98.5%) as carbon source. The evaluation of the operational stability allowed 12 cycles of biomass reuse using the IM and 9 cycles using the SM. After physical-chemical treatment, only SM denitrified water remained within drinking water standards parameters of color and turbidity. Copyright © 2018 Elsevier Ltd. All rights reserved.

Gaining ground in the modeling of land-use change greenhouse gas emissions associated with biofuel production

NASA Astrophysics Data System (ADS)

Dunn, J.; Mueller, S.; Kwon, H.; Wang, M.; Wander, M.

2012-12-01

Land-use change (LUC) resulting from biofuel feedstock production and the associated greenhouse gas (GHG) emissions are a hotly-debated aspect of biofuels. Certainly, LUC GHG emissions are one of the most uncertain elements in life cycle analyses (LCA) of biofuels. To estimate LUC GHG emissions, two sets of data are necessary. First, information on the amount and type of land that is converted to biofuel feedstock production is required. These data are typically generated through application of computable general equilibrium (CGE) models such as Purdue University's Global Trade Analysis Project (GTAP) model. Second, soil carbon content data for the affected land types is essential. Recently, Argonne National Laboratory's Carbon Calculator for Land Use Change from Biofuels Production (CCLUB) has been updated with CGE modeling results that estimate the amount and type of LUC world-wide from production of ethanol from corn, corn stover, miscanthus, and switchgrass (Mueller et al. 2012). Moreover, we have developed state-specific carbon content data, determined through modeling with CENTURY, for the two most dominant soil types in the conterminous 48 U.S. states (Kwon et al. 2012) to enable finer-resolution results for domestic LUC GHG emissions for these ethanol production scenarios. Of the feedstocks examined, CCLUB estimates that LUC GHG emissions are highest for corn ethanol (9.1 g CO2e/MJ ethanol) and lowest for miscanthus (-12 g CO2e/MJ ethanol). We will present key observations from CCLUB results incorporated into Argonne National Laboratory's Greenhouse Gases, Regulated Emissions, and Energy use in Transportation (GREET) model, which is a LCA tool for transportation fuels and advanced vehicle technologies. We will discuss selected issues in this modeling, including the sensitivity of domestic soil carbon emission factors to modeling parameters and assumptions about the fate of harvested wood products. Further, we will discuss efforts to update CCLUB with county-level soil carbon emission factors and updated international soil carbon emission factors. Finally, we will examine data needs for improved LUC GHG calculations in both the modeling of land conversion and soil carbon content. Kwon, H. Y., Wander, M. M., Mueller, S., Dunn, J. B. "Modeling state-level soil carbon emission factors under various scenarios for direct land use change associated with United States biofuel feedstock production." Biomass and Bioenergy. Under Review. Mueller, S., Dunn, J. B., Wang, M. "Carbon Calculator for Land Use Change from Biofuels Production (CCLUB) Users' Manual and Technical Documentation." May 2012. ANL/ESD/12-5. Available at http://greet.es.anl.gov/publication-cclub-manual.

Atmospheric ethanol in London and the potential impacts of future fuel formulations.

PubMed

Dunmore, Rachel E; Whalley, Lisa K; Sherwen, Tomás; Evans, Mathew J; Heard, Dwayne E; Hopkins, James R; Lee, James D; Lewis, Alastair C; Lidster, Richard T; Rickard, Andrew R; Hamilton, Jacqueline F

2016-07-18

There is growing global consumption of non-fossil fuels such as ethanol made from renewable biomass. Previous studies have shown that one of the main air quality disadvantages of using ethanol blended fuels is a significant increase in the production of acetaldehyde, an unregulated and toxic pollutant. Most studies on the impacts of ethanol blended gasoline have been carried out in the US and Brazil, with much less focus on the UK and Europe. We report time resolved measurements of ethanol in London during the winter and summer of 2012. In both seasons the mean mixing ratio of ethanol was around 5 ppb, with maximum values over 30 ppb, making ethanol currently the most abundant VOC in London air. We identify a road transport related source, with 'rush-hour' peaks observed. Ethanol is strongly correlated with other road transport-related emissions, such as small aromatics and light alkanes, and has no relationship to summer biogenic emissions. To determine the impact of road transport-related ethanol emission on secondary species (i.e. acetaldehyde and ozone), we use both a chemically detailed box model (incorporating the Master Chemical Mechanism, MCM) and a global and nested regional scale chemical transport model (GEOS-Chem), on various processing time scales. Using the MCM model, only 16% of the modelled acetaldehyde was formed from ethanol oxidation. However, the model significantly underpredicts the total levels of acetaldehyde, indicating a missing primary emission source, that appears to be traffic-related. Further support for a primary emission source comes from the regional scale model simulations, where the observed concentrations of ethanol and acetaldehyde can only be reconciled with the inclusion of large primary emissions. Although only constrained by one set of observations, the regional modelling suggests a European ethanol source similar in magnitude to that of ethane (∼60 Gg per year) and greater than that of acetaldehyde (∼10 Gg per year). The increased concentrations of ethanol and acetaldehyde from primary emissions impacts both radical and NOx cycling over Europe, resulting in significant regional impacts on NOy speciation and O3 concentrations, with potential changes to human exposure to air pollutants.

Hierarchical structures of carbon nanotubes and arrays of chromium-capped silicon nanopillars: formation and electrical properties.

PubMed

Koch, Stefan; Joshi, Ravi K; Noyong, Michael; Timper, Jan; Schneider, Jörg J; Simon, Ulrich

2012-09-10

The formation of stochastically oriented carbon-nanotube networks on top of an array of free-standing chromium-capped silicon nanopillars is reported. The combination of nanosphere lithography and chemical vapor deposition enables the construction of nanostructures that exhibit a hierarchical sequence of structural sizes. Metallic chromium serves as an etching mask for Si-pillar formation and as a nucleation site for the formation of carbon nanotubes through the chemical vapor deposition of ethene, ethanol, and methane, respectively, thereby bridging individual pillars from top to top. Iron and cobalt were applied onto the chromium caps as catalysts for CNT growth and the influence of different carbon sources and different gas-flow rates were investigated. The carbon nanotubes were structurally characterized and their DC electrical properties were studied by in situ local- and ex situ macroscopic measurements, both of which reveal their semiconductor properties. This process demonstrates how carbon nanotubes can be integrated into Si-based semiconductors and, thus, this process may be used to form high-surface-area sensors or new porous catalyst supports with enhanced gas-permeation properties. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

LIQUID BIO-FUEL PRODUCTION FROM NON-FOOD BIOMASS VIA HIGH TEMPERATURE STEAM ELECTROLYSIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

G. L. Hawkes; J. E. O'Brien; M. G. McKellar

2011-11-01

Bio-Syntrolysis is a hybrid energy process that enables production of synthetic liquid fuels that are compatible with the existing conventional liquid transportation fuels infrastructure. Using biomass as a renewable carbon source, and supplemental hydrogen from high-temperature steam electrolysis (HTSE), bio-syntrolysis has the potential to provide a significant alternative petroleum source that could reduce US dependence on imported oil. Combining hydrogen from HTSE with CO from an oxygen-blown biomass gasifier yields syngas to be used as a feedstock for synthesis of liquid transportation fuels via a Fischer-Tropsch process. Conversion of syngas to liquid hydrocarbon fuels, using a biomass-based carbon source, expandsmore » the application of renewable energy beyond the grid to include transportation fuels. It can also contribute to grid stability associated with non-dispatchable power generation. The use of supplemental hydrogen from HTSE enables greater than 90% utilization of the biomass carbon content which is about 2.5 times higher than carbon utilization associated with traditional cellulosic ethanol production. If the electrical power source needed for HTSE is based on nuclear or renewable energy, the process is carbon neutral. INL has demonstrated improved biomass processing prior to gasification. Recyclable biomass in the form of crop residue or energy crops would serve as the feedstock for this process. A process model of syngas production using high temperature electrolysis and biomass gasification is presented. Process heat from the biomass gasifier is used to heat steam for the hydrogen production via the high temperature steam electrolysis process. Oxygen produced form the electrolysis process is used to control the oxidation rate in the oxygen-blown biomass gasifier. Based on the gasifier temperature, 94% to 95% of the carbon in the biomass becomes carbon monoxide in the syngas (carbon monoxide and hydrogen). Assuming the thermal efficiency of the power cycle for electricity generation is 50%, (as expected from GEN IV nuclear reactors), the syngas production efficiency ranges from 70% to 73% as the gasifier temperature decreases from 1900 K to 1500 K. Parametric studies of system pressure, biomass moisture content and low temperature alkaline electrolysis are also presented.« less

Microfluidic Synthesis Enables Dense and Uniform Loading of Surfactant-Free PtSn Nanocrystals on Carbon Supports for Enhanced Ethanol Oxidation.

PubMed

Wu, Fuxiang; Zhang, Dongtang; Peng, Manhua; Yu, Zhihui; Wang, Xiayan; Guo, Guangsheng; Sun, Yugang

2016-04-11

Developing new synthetic methods for carbon supported catalysts with improved performance is of fundamental importance in advancing proton exchange membrane fuel cell (PEMFC) technology. Continuous-flow, microfluidic reactions in capillary tube reactors are described, which are capable of synthesizing surfactant-free, ultrafine PtSn alloyed nanoparticles (NPs) on various carbon supports (for example, commercial carbon black particles, carbon nanotubes, and graphene sheets). The PtSn NPs are highly crystalline with sizes smaller than 2 nm, and they are highly dispersed on the carbon supports with high loadings up to 33 wt%. These characteristics make the as-synthesized carbon-supported PtSn NPs more efficient than state of the art commercial Pt/C catalysts applied to the ethanol oxidation reaction (EOR). Significantly enhanced mass catalytic activity (two-times that of Pt/C) and improved stability are obtained. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simulation of homogeneous condensation of small polyatomic systems in high pressure supersonic nozzle flows using Bhatnagar-Gross-Krook model

NASA Astrophysics Data System (ADS)

Kumar, Rakesh; Levin, Deborah A.

2011-03-01

In the present work, we have simulated the homogeneous condensation of carbon dioxide and ethanol using the Bhatnagar-Gross-Krook based approach. In an earlier work of Gallagher-Rogers et al. [J. Thermophys. Heat Transfer 22, 695 (2008)], it was found that it was not possible to simulate condensation experiments of Wegener et al. [Phys. Fluids 15, 1869 (1972)] using the direct simulation Monte Carlo method. Therefore, in this work, we have used the statistical Bhatnagar-Gross-Krook approach, which was found to be numerically more efficient than direct simulation Monte Carlo method in our previous studies [Kumar et al., AIAA J. 48, 1531 (2010)], to model homogeneous condensation of two small polyatomic systems, carbon dioxide and ethanol. A new weighting scheme is developed in the Bhatnagar-Gross-Krook framework to reduce the computational load associated with the study of homogeneous condensation flows. The solutions obtained by the use of the new scheme are compared with those obtained by the baseline Bhatnagar-Gross-Krook condensation model (without the species weighting scheme) for the condensing flow of carbon dioxide in the stagnation pressure range of 1-5 bars. Use of the new weighting scheme in the present work makes the simulation of homogeneous condensation of ethanol possible. We obtain good agreement between our simulated predictions for homogeneous condensation of ethanol and experiments in terms of the point of condensation onset and the distribution of mass fraction of ethanol condensed along the nozzle centerline.

Sulfate Salts in Gasoline and Ethanol Fuels -- Historical Perspective and Analysis of Available Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCormick, Robert L.; Alleman, Teresa; Yanowitz, Janet

This report reviews the chemistry of sulfate salts dissolved in ethanol and gasoline, potential sources of sulfate salts in ethanol and gasoline, the history of consumer vehicle issues with sulfate salt deposits in the early 2000s, and the corresponding changes to the denatured fuel ethanol specification. Recommendations for future research are provided. During a period of rapid market expansion in 2004-05, issues were reported with vehicles running on E10 provided by certain suppliers in some markets. It was commonly believed that these vehicle problems were caused by sulfate salts precipitating from the fuel. Investigators identified sodium sulfate, and in onemore » case also ammonium sulfate, as the predominate salts found in the engines. Several stakeholders believed the issue was excess sulfate ions in the ethanol portion of the E10, and in 2005 the ASTM specification for ethanol (D4806) was modified to include a 4-part per million (ppm) limit on sulfate ions. While there have been no further reports of consumer vehicle issues, the recently approved increase of ethanol in gasoline from 10 to 15 volume percent has resulted in renewed interest in the sulfate ion concentration in fuel ethanol. This report reviews published data on the solubility of sulfate salts in ethanol. The possible sources of sulfate anions and charge balancing cations (such as sodium) in fuel ethanol and petroleum derived blendstocks are discussed. Examination of historical information on the consumer vehicle issues that occurred in 2004-2005 reveals that a source of sodium or ammonium ions, required for the formation of the observed insoluble salts, was never identified. Recommendations for research to better understand sulfate salt solubility issues in ethanol, hydrocarbon blendstocks, and ethanol-gasoline blends are presented.« less

Assessment of Ethanol Trends on the ISS

NASA Technical Reports Server (NTRS)

Perry, Jay; Carter, Layne; Kayatin, Matthew; Gazda, Daniel; McCoy, Torin; Limero, Thomas

2016-01-01

The International Space Station (ISS) Environmental Control and Life Support System (ECLSS) provides a working environment for six crewmembers through atmosphere revitalization and water recovery systems. In the last year, elevated ethanol levels have presented a unique challenge for the ISS ECLSS. Ethanol is monitored on the ISS by the Air Quality Monitor (AQM). The source of this increase is currently unknown. This paper documents the credible sources for the increased ethanol concentration, the monitoring provided by the AQM, and the impact on the atmosphere revitalization and water recovery systems.

Postmortem ethanol in the setting of ethanol-containing automotive fuel.

PubMed

Garber, Mitchell A; Canfield, Dennis V; Lewis, Russell J; Simmons, Samuel D; Radisch, Deborah L

2013-03-01

The pilot of a light aircraft that crashed after a loss of power was found to have ethanol in the vitreous and the blood, but almost none in the urine. The globes of the eyes were intact, and the body was refrigerated after recovery until the autopsy was performed the following morning. The pilot was described as a "nondrinker," and additional specialized toxicology testing results were inconsistent with ethanol ingestion. The pilot's body was extensively exposed to fuel during the prolonged extraction. Investigation determined that the aircraft had been fueled with gasoline that contained 10% ethanol. Although exposure to automotive fuel has not been previously described as a source of ethanol in postmortem specimens, it may represent a source for the ethanol detected during postmortem toxicology testing in this case, and this finding may be relevant to other cases with similar exposure.

At $2.15 a Gallon, Cellulosic Ethanol Could Be Cost Competitive -

Science.gov Websites

Continuum Magazine | NREL At $2.15 a Gallon, Cellulosic Ethanol Could Be Cost Competitive In cellulose microfibrils. Photo by Dennis Schroeder, NREL At $2.15 a Gallon, Cellulosic Ethanol Could Be Cost ethanol-ethanol from non-food plant sources-in a way that is cost competitive with other transportation

Fuel From Farms: A Guide to Small-Scale Ethanol Production.

ERIC Educational Resources Information Center

Solar Energy Research Inst., Golden, CO.

Ethanol and blends of ethanol and gasoline (such as gasohol) offer a near-term fuel alternative to oil. The focus of this handbook is upon the small-scale production of ethanol using farm crops as the source of raw materials. Provided are chapters on ethanol production procedures, feedstocks, plant design, and financial planning. Also presented…

Time-Series Similarity Analysis of Satellite Derived Data to Understand Changes in Forest Biomass.

NASA Astrophysics Data System (ADS)

Singh, N.; Fritz, B.

2017-12-01

One of the goals of promoting bioenergy is reducing green-house gas emissions by replacing fossil fuels. However, there are concerns that carbon emissions due to changes in land use resulting from crop production for ethanol will negate the impact of biofuels on the environment. So, the current focus is to use lignocellulose feedstocks also referred to as second generation biofuels as the new source of bioenergy. Wood based pellets derived from the forests of southeastern United States are one such source which is being exported to Europe as a carbon-neutral fuel. These wood-pellets meet the EU standard for carbon emissions and are being used to replace coal for energy generation and heating. As a result US exports of wood-based pellets have increased from nearly zero to over 6 million metric tons over the past 8 years. Wood-based pellets are traditionally produced from softwood trees which have a relatively shorter life-cycle and propagate easily, and thus are expected to provide a sustainable source of wood chips used for pellet production. However, there are concerns that as the demand and price of wood pellets increases, lumber mills will seek wood chips from other sources as well, particularly from hardwood trees resulting in higher carbon emissions as well as loss of biodiversity. In this study we use annual stacks of normalized difference vegetation index (NDVI) data at a 16-day temporal resolution to monitor biomass around pellet mills in southeastern United States. We use a combination of time series similarity technique and supervised learning to understand if there have been significant changes in biomass around pellet mills in the southeastern US. We also demonstrate how our method can be used to monitor biomass over large geographic regions using phenological properties of growing vegetation.

Thermophilic Gram-Positive Biocatalysts for Biomass Conversion to Ethanol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shanmugam, K.T.; Ingram, L.O.; Maupin-Furlow, J.A.

2003-12-01

Production of energy from renewable sources is receiving increased attention due to the finite nature of fossil fuels and the environmental impact associated with the continued large scale use of fossil energy sources. Biomass, a CO2-neutral abundant resource, is an attractive alternate source of energy. Biomass-derived sugars, such as glucose, xylose, and other minor sugars, can be readily fermented to fuel ethanol and commodity chemicals. Extracellular cellulases produced by fungi are commercially developed for depolymerization of cellulose in biomass to glucose for fermentation by appropriate biocatalysts in a simultaneous saccharification and fermentation (SSF) process. Due to the differences in themore » optimum conditions for the activity of the fungal cellulases and the growth and fermentation characteristics of the current industrial biocatalysts, SSF of cellulose is envisioned at conditions that are not optimal for the fungal cellulase activity leading to higher than required cost of cellulase in SSF. We have isolated bacterial biocatalysts whose growth and fermentation requirements match the optimum conditions for commercial fungal cellulase activity (pH 5.0 and 50 deg. C). These isolates fermented both glucose and xylose, major components of cellulose and hemicellulose, respectively, to L(+)-lactic acid. Xylose was metabolized through the pentose-phosphate pathway by these organisms as evidenced by the fermentation profile and analysis of the fermentation products of 13C1-xylose by NMR. As expected for the metabolism of xylose by the pentose-phosphate pathway, 13C-lactate accounted for more than 90% of the total 13C-labeled products. All three strains fermented crystalline cellulose to lactic acid with the addition of fungal cellulase (Spezyme CE) (SSF) at an optimum of about 10 FPU/g cellulose. These isolates also fermented cellulose and sugar cane bagasse hemicellulose acid hydrolysate simultaneously. Based on fatty acid profile and 16S rRNA sequence, these isolates cluster with Bacillus coagulans although B. coagulans type strain, ATCC 7050, failed to utilize xylose as a carbon source. For successful production of ethanol from pyruvate, both pyruvate decarboxylase (PDC) and alcohol dehydrogenase (AHD) need to be produced at optimal levels in these biocatalysts. A plasmid containing the S. ventriculi pdc gene and the adh gene from geobacillus stearothermophilus was constructed using plasmid pWH1520 that was successfully used for expression of pdc in B. megaterium. The resulting portable ethanol (PET) plasmid, pJAM423, was transformed into B. megaterium. After xylose induction, a significant fraction of cell cytoplasm was composed of the S. ventriculi PDC and G. stearothermophilus ADH proteins. In preliminary experiments, the amount of ethanol produced by b. megaterium with plasmid pJAM423 was about twice (20 mM) of the bacterium without the plasmid. These results show that the PET operon is functional in B. megaterium but high level ethanol production needs further genetic and metabolic engineering. A genetic transfer system for the second generation biocatalysts needs to be developed for transferring the plasmid pJAM423 and its derivatives for engineering these organisms for ethanol production from biomass derived sugars and cellulose to ethanol. One of the new biocatalysts, strain P4-102B was found to be transformable with plasmids and the method for introducing plasmid pJAM423 into this strain and expression of the encoded DNA is being optimized. These new second generation biocatalysts have the potential to reduce the cost of SSF by minimizing the amount of fungal cellulases, a significant cost component in the use of biomass as a renewable resource for production of fuels and chemicals.« less

Carbon monoxide alleviates ethanol-induced oxidative damage and inflammatory stress through activating p38 MAPK pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yanyan; Gao, Chao; Shi, Yanru

2013-11-15

Stress-inducible protein heme oxygenase-1(HO-1) is well-appreciative to counteract oxidative damage and inflammatory stress involving the pathogenesis of alcoholic liver diseases (ALD). The potential role and signaling pathways of HO-1 metabolite carbon monoxide (CO), however, still remained unclear. To explore the precise mechanisms, ethanol-dosed adult male Balb/c mice (5.0 g/kg.bw.) or ethanol-incubated primary rat hepatocytes (100 mmol/L) were pretreated by tricarbonyldichlororuthenium (II) dimmer (CORM-2, 8 mg/kg for mice or 20 μmol/L for hepatocytes), as well as other pharmacological reagents. Our data showed that CO released from HO-1 induction by quercetin prevented ethanol-derived oxidative injury, which was abolished by CO scavenger hemoglobin.more » The protection was mimicked by CORM-2 with the attenuation of GSH depletion, SOD inactivation, MDA overproduction, and the leakage of AST, ALT or LDH in serum and culture medium induced by ethanol. Moreover, CORM-2 injection or incubation stimulated p38 phosphorylation and suppressed abnormal Tnfa and IL-6, accompanying the alleviation of redox imbalance induced by ethanol and aggravated by inflammatory factors. The protective role of CORM-2 was abolished by SB203580 (p38 inhibitor) but not by PD98059 (ERK inhibitor) or SP600125 (JNK inhibitor). Thus, HO-1 released CO prevented ethanol-elicited hepatic oxidative damage and inflammatory stress through activating p38 MAPK pathway, suggesting a potential therapeutic role of gaseous signal molecule on ALD induced by naturally occurring phytochemicals. - Highlights: • CO alleviated ethanol-derived liver oxidative and inflammatory stress in mice. • CO eased ethanol and inflammatory factor-induced oxidative damage in hepatocytes. • The p38 MAPK is a key signaling mechanism for the protective function of CO in ALD.« less

Effect of Ethanol Blends and Batching Operations on SCC of Carbon Steel

DOT National Transportation Integrated Search

2011-02-08

This is the draft final report of the project on blending and batching (WP#325) of the Consolidated Program on Development of Guidelines for Safe and Reliable Pipeline Transportation of Ethanol Blends. The other two aspects of the consolidated progra...

Soil and variety effects on the energy and carbon balances of switchgrass-derived ethanol

USDA-ARS?s Scientific Manuscript database

This study examined the effects of soil and switchgrass variety on sustainability and eco-friendliness of switchgrass-based ethanol production. Using the Agricultural Land Management Alternatives with Numerical Assessment Criteria (ALMANAC) model, switchgrass biomass yields were simulated for severa...

Self Assembly and Properties of C:WO3 Nano-Platelets and C:VO2/V2O5 Triangular Capsules Produced by Laser Solution Photolysis

PubMed Central

2010-01-01

Laser photolysis of WCl6 in ethanol and a specific mixture of V2O5 and VCl3 in ethanol lead to carbon modified vanadium and tungsten oxides with interesting properties. The presence of graphene’s aromatic rings (from the vibrational frequency of 1,600 cm−1) together with C–C bonding of carbon (from the Raman shift of 1,124 cm−1) present unique optical, vibrational, electronic and structural properties of the intended tungsten trioxide and vanadium dioxide materials. The morphology of these samples shows nano-platelets in WOx samples and, in VOx samples, encapsulated spherical quantum dots in conjunction with fullerenes of VOx. Conductivity studies revealed that the VO2/V2O5 nanostructures are more sensitive to Cl than to the presence of ethanol, whereas the C:WO3 nano-platelets are more sensitive to ethanol than atomic C. PMID:20671779

Carbon Nanotubes Blended Hydroxyapatite Ethanol Sensor

NASA Astrophysics Data System (ADS)

Anjum, S. R.; Khairnar, R. S.

2016-12-01

Nano crystals of Hydroxyapatite (HAp) were synthesized by a wet chemical precipitation method. The nano composite materials were developed by doping various weight concentrations of carbon nanotubes in HAp, followed by characterization using scanning electron microscopy, and X-ray diffraction. Thick films of these materials were prepared by using screen printing technique. The ethanol sensing properties of these nano crystals and nano composite films were investigated by two probe electrical method. The gas sensing features such as operating temperature, response and recovery time, maximum gas detection limit, etc. were studied, since these parameters are of prime importance for sensor. The results revealed that at room temperature, the composite materials exhibited improved sensing performance towards 100 ppm ethanol with fast response times. It also showed shorter recovery time with higher vapor uptake capacity. The ethanol adsorption processes on doped and undoped substrates can be explained by surface chemical reactions as well as providing the possible adsorption models. The novelty of this work lies in developing reusable sensor substrates for room temperature sensing.

A facile self-assembly approach to prepare palladium/carbon nanotubes catalyst for the electro-oxidation of ethanol

NASA Astrophysics Data System (ADS)

Wen, Cuilian; Zhang, Xinyuan; Wei, Ying; Zhang, Teng; Chen, Changxin

2018-02-01

A facile self-assembly approach is reported to prepare palladium/carbon nanotubes (Pd/CNTs) catalyst for the electro-oxidation of ethanol. In this method, the Pd-oleate/CNTs was decomposed into the Pd/CNTs at an optimal temperature of 195 °C in air, in which no inert gas is needed for the thermal decomposition process due to the low temperature used and the decomposed products are also environmental friendly. The prepared Pd/CNTs catalyst has a high metallic Pd0 content and the Pd particles in the catalyst are disperse, uniform-sized with an average size of ˜2.1 nm, and evenly distributed on the CNTs. By employing our strategy, the problems including the exfoliation of the metal particles from the CNTs and the aggregation of the metal particles can be solved. Comparing with the commercial Pd/C one, the prepared Pd/CNTs catalyst exhibits a much higher electrochemical activity and stability for the electro-oxidation of ethanol in the direct ethanol fuel cells.

Near-term deployment of carbon capture and sequestration from biorefineries in the United States.

PubMed

Sanchez, Daniel L; Johnson, Nils; McCoy, Sean T; Turner, Peter A; Mach, Katharine J

2018-05-08

Capture and permanent geologic sequestration of biogenic CO 2 emissions may provide critical flexibility in ambitious climate change mitigation. However, most bioenergy with carbon capture and sequestration (BECCS) technologies are technically immature or commercially unavailable. Here, we evaluate low-cost, commercially ready CO 2 capture opportunities for existing ethanol biorefineries in the United States. The analysis combines process engineering, spatial optimization, and lifecycle assessment to consider the technical, economic, and institutional feasibility of near-term carbon capture and sequestration (CCS). Our modeling framework evaluates least cost source-sink relationships and aggregation opportunities for pipeline transport, which can cost-effectively transport small CO 2 volumes to suitable sequestration sites; 216 existing US biorefineries emit 45 Mt CO 2 annually from fermentation, of which 60% could be captured and compressed for pipeline transport for under $25/tCO 2 A sequestration credit, analogous to existing CCS tax credits, of $60/tCO 2 could incent 30 Mt of sequestration and 6,900 km of pipeline infrastructure across the United States. Similarly, a carbon abatement credit, analogous to existing tradeable CO 2 credits, of $90/tCO 2 can incent 38 Mt of abatement. Aggregation of CO 2 sources enables cost-effective long-distance pipeline transport to distant sequestration sites. Financial incentives under the low-carbon fuel standard in California and recent revisions to existing federal tax credits suggest a substantial near-term opportunity to permanently sequester biogenic CO 2 This financial opportunity could catalyze the growth of carbon capture, transport, and sequestration; improve the lifecycle impacts of conventional biofuels; support development of carbon-negative fuels; and help fulfill the mandates of low-carbon fuel policies across the United States. Copyright © 2018 the Author(s). Published by PNAS.

Transcriptional and Proteomic Responses to Carbon Starvation in Paracoccidioides

PubMed Central

Lima, Patrícia de Sousa; Casaletti, Luciana; Bailão, Alexandre Melo; de Vasconcelos, Ana Tereza Ribeiro; Fernandes, Gabriel da Rocha; Soares, Célia Maria de Almeida

2014-01-01

Background The genus Paracoccidioides comprises human thermal dimorphic fungi, which cause paracoccidioidomycosis (PCM), an important mycosis in Latin America. Adaptation to environmental conditions is key to fungal survival during human host infection. The adaptability of carbon metabolism is a vital fitness attribute during pathogenesis. Methodology/Principal Findings The fungal pathogen Paracoccidioides spp. is exposed to numerous adverse conditions, such as nutrient deprivation, in the human host. In this study, a comprehensive response of Paracoccidioides, Pb01, under carbon starvation was investigated using high-resolution transcriptomic (RNAseq) and proteomic (NanoUPLC-MSE) approaches. A total of 1,063 transcripts and 421 proteins were differentially regulated, providing a global view of metabolic reprogramming during carbon starvation. The main changes were those related to cells shifting to gluconeogenesis and ethanol production, supported by the degradation of amino acids and fatty acids and by the modulation of the glyoxylate and tricarboxylic cycles. This proposed carbon flow hypothesis was supported by gene and protein expression profiles assessed using qRT-PCR and western blot analysis, respectively, as well as using enzymatic, cell dry weight and fungus-macrophage interaction assays. The carbon source provides a survival advantage to Paracoccidioides inside macrophages. Conclusions/Significance For a complete understanding of the physiological processes in an organism, the integration of approaches addressing different levels of regulation is important. To the best of our knowledge, this report presents the first description of the responses of Paracoccidioides spp. to host-like conditions using large-scale expression approaches. The alternative metabolic pathways that could be adopted by the organism during carbon starvation can be important for a better understanding of the fungal adaptation to the host, because systems for detecting and responding to carbon sources play a major role in adaptation and persistence in the host niche. PMID:24811072

Synthetic Klebsiella pneumoniae-Shewanella oneidensis Consortium Enables Glycerol-Fed High-Performance Microbial Fuel Cells.

PubMed

Li, Feng; Yin, Changji; Sun, Liming; Li, Yuanxiu; Guo, Xuewu; Song, Hao

2018-05-01

Microbial fuel cell (MFC) is an eco-friendly bio-electrochemical sys-tem that uses microorganism as biocatalyst to convert biomass into electricity. Glycerol, as a waste in the biodiesel refinery processes, is an appealing substrate for MFC. Nevertheless, glycerol cannot be utilized as carbon source by well-known exoelectrogens such as Shewanella oneidensis. Herein, to generate electricity by rapidly harnessing glycerol, the authors rationally constructed a Klebsiella pneumoniae-Shewanella oneidensis microbial consortium to efficiently harvest electricity from glyc-erol, in which K. pneumoniae converted glycerol into lactate, fed to S. oneidensis as carbon source and electron donor. To improve electricity output, the authors systematically engineered the consortium in terms of carbon flux distribution and efficiency of extracellular electron transfer (EET). To direct more carbon flux to lactate biosynthesis in K. pneumoniae, the authors eliminated the ethanol pathway by knocking out the alcohol dehydrogenase gene (adhE), and enhanced lactate biosynthesis by heterologously expressing a lactate dehydrogen-ase gene (ldhD) from Lactobacillus bulgaricus and a lactate transporter gene (lldP) from Escherichia coli. To facilitate EET between S. oneidensis and anode surfaces, a biosynthetic flavins pathway from Bacillus subtilis is introduced into S. oneidensis. The author further optimized the glycerol concentration, thus S. oneidensis could be continuously fed with lactate synthesized from K. pneumoniae at a constant rate. Our glycerol-fed MFC generated a maximum power density of 19.9 mW/m 2 , significantly higher than that of the wild-type consor-tium. This work suggested that engineering microbial consortia is an effi-cient strategy to expand the spectrum of usable carbon sources and promote electricity power production in MFCs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Antioxidant potential of Juglans nigra, black walnut, husks extracted using supercritical carbon dioxide with an ethanol modifier.

PubMed

Wenzel, Jonathan; Storer Samaniego, Cheryl; Wang, Lihua; Burrows, Laron; Tucker, Evan; Dwarshuis, Nathan; Ammerman, Michelle; Zand, Ali

2017-03-01

The black walnut, Junglas nigra, is indigenous to eastern North America, and abscission of its fruit occurs around October. The fruit consists of a husk, a hard shell, and kernel. The husk is commonly discarded in processing, though it contains phenolic compounds that exhibit antioxidant and antimicrobial properties. For this study, black walnut husks were extracted using supercritical carbon dioxide with an ethanol modifier. The effects of temperature, ethanol concentration, and drying of walnut husks prior to extraction upon antioxidant potential were evaluated using a factorial design of experiments. The solvent density was held constant at 0.75 g/mL. The optimal extraction conditions were found to be 68°C and 20 wt-% ethanol in supercritical carbon dioxide. At these conditions, the antioxidant potential as measured by the ferric reducing ability of plasma (FRAP) assay was 0.027 mmol trolox equivalent/g (mmol TE/g) for dried walnut husk and 0.054 mmol TE/g for walnut husks that were not dried. Antioxidant potential was also evaluated using the total phenolic content (TPC) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assays and the FRAP assay was found to linearly correlate to the TPC assay.

Extraction of methylxanthines from guaraná seeds, maté leaves, and cocoa beans using supercritical carbon dioxide and ethanol.

PubMed

Saldaña, Marleny D A; Zetzl, Carsten; Mohamed, Rahoma S; Brunner, G

2002-08-14

New experimental data on the extraction of caffeine from guaraná seeds and maté tea leaves, and theobromine from cocoa beans, with supercritical CO2 were obtained using a high-pressure extraction apparatus. The effect of the addition of ethanol to carbon dioxide on the extraction efficiency was also investigated. Caffeine extraction yields of 98% of the initial caffeine content in both wet ground guaraná seeds and maté tea leaves were obtained. Extractions of caffeine from guaraná seeds and maté tea leaves also exhibited a retrograde behavior for the two temperatures considered in this work. In the removal of theobromine from cocoa beans, a much smaller extraction yield was obtained with longer extraction periods and consequently larger solvent requirements. The results of this study confirm the higher selectivity of CO2 for caffeine in comparison with that for theobromine, and also the influence of other components in each particular natural product on the extraction of methylxanthines. The effect of the addition of ethanol to carbon dioxide on the extraction of methylxanthines was significant, particularly in the extraction of theobromine from cocoa beans. In general, the use of ethanol results in lower solvent and energy requirements and thereby improved extraction efficiency.

Anticorrosive Influence of Acetobacter aceti Biofilms on Carbon Steel

NASA Astrophysics Data System (ADS)

France, Danielle Cook

2016-09-01

Microbiologically influenced corrosion (MIC) of carbon steel infrastructure is an emerging environmental and cost issue for the ethanol fuel industry, yet its examination lacks rigorous quantification of microbiological parameters that could reveal effective intervention strategies. To quantitatively characterize the effect of cell concentration on MIC of carbon steel, numbers of bacteria exposed to test coupons were systematically controlled to span four orders of magnitude throughout a seven-day test. The bacterium studied, Acetobacter aceti, has been found in ethanol fuel environments and can convert ethanol to the corrosive species acetic acid. A. aceti biofilms formed during the test were qualitatively evaluated with fluorescence microscopy, and steel surfaces were characterized by scanning electron microscopy. During exposure, biofilms developed more quickly, and test reactor pH decreased at a faster rate, when cell exposure was higher. Resulting corrosion rates, however, were inversely proportional to cell exposure, indicating that A. aceti biofilms are able to protect carbon steel surfaces from corrosion. This is a novel demonstration of corrosion inhibition by an acid-producing bacterium that occurs naturally in corrosive environments. Mitigation techniques for MIC that harness the power of microbial communities have the potential to be scalable, inexpensive, and green solutions to industrial problems.

Preparation and characterization of carbon-supported sub-monolayer palladium decorated gold nanoparticles for the electro-oxidation of ethanol in alkaline media

NASA Astrophysics Data System (ADS)

Zhu, L. D.; Zhao, T. S.; Xu, J. B.; Liang, Z. X.

Carbon-supported gold nanoparticles (Au/C) are successfully decorated with mono- or sub-monolayer palladium atoms with different Pd/Au atomic ratios by a chemically epitaxial seeded growth method. TEM, UV-vis spectrometry and XRD techniques are used to characterize the particle size, dispersion, palladium coverage on gold seeds and crystal structures of the prepared catalysts. Cyclic voltammetric tests show that the Pd-decorated Au/C (denoted by Pd@Au/C) have higher specific activities than that of Pd/C for the oxidation of ethanol in alkaline media. This suggests that the Pd utilization is improved with such a surface-alloyed nanostructure. In addition, stable chronoamperometric responses are achieved with the so-prepared electrocatalysts during ethanol oxidation.

Furfural and ethanol production from corn stover by dilute phosphoric acid pretreatment

USDA-ARS?s Scientific Manuscript database

Lignocellulosic biomass is the most abundant carbohydrate source in the world and has potential for economical production of biofuels, especially ethanol. However, its composition is an obstacle for the production of ethanol by the conventional ethanol producing yeast Saccharomyces cerevisiae as it...

Climate and land use: Forgive us our carbon debts

NASA Astrophysics Data System (ADS)

Macedo, Marcia N.; Davidson, Eric A.

2014-07-01

Sugar cane ethanol replaces fossil fuels, but changes in soil carbon could offset some of the benefit. Now, a study shows minor loss of soil carbon when pastures and croplands are converted to cane, but larger losses when converting native savannahs.

A novel cell factory for efficient production of ethanol from dairy waste.

PubMed

Liu, Jianming; Dantoft, Shruti Harnal; Würtz, Anders; Jensen, Peter Ruhdal; Solem, Christian

2016-01-01

Sustainable and economically feasible ways to produce ethanol or other liquid fuels are becoming increasingly relevant due to the limited supply of fossil fuels and the environmental consequences associated with their consumption. Microbial production of fuel compounds has gained a lot of attention and focus has mostly been on developing bio-processes involving non-food plant biomass feedstocks. The high cost of the enzymes needed to degrade such feedstocks into its constituent sugars as well as problems due to various inhibitors generated in pretreatment are two challenges that have to be addressed if cost-effective processes are to be established. Various industries, especially within the food sector, often have waste streams rich in carbohydrates and/or other nutrients, and these could serve as alternative feedstocks for such bio-processes. The dairy industry is a good example, where large amounts of cheese whey or various processed forms thereof are generated. Because of their nutrient-rich nature, these substrates are particularly well suited as feedstocks for microbial production. We have generated a Lactococcus lactis strain which produces ethanol as its sole fermentation product from the lactose contained in residual whey permeate (RWP), by introducing lactose catabolism into a L. lactis strain CS4435 (MG1363 Δ(3) ldh, Δpta, ΔadhE, pCS4268), where the carbon flow has been directed toward ethanol instead of lactate. To achieve growth and ethanol production on RWP, we added corn steep liquor hydrolysate (CSLH) as the nitrogen source. The outcome was efficient ethanol production with a titer of 41 g/L and a yield of 70 % of the theoretical maximum using a fed-batch strategy. The combination of a low-cost medium from industrial waste streams and an efficient cell factory should make the developed process industrially interesting. A process for the production of ethanol using L. lactis and a cheap renewable feedstock was developed. The results demonstrate that it is possible to achieve sustainable bioconversion of waste products from the dairy industry (RWP) and corn milling industry (CSLH) to ethanol and the process developed shows great potential for commercial realization.

Rapid synthesis of platinum-ruthenium bimetallic nanoparticles dispersed on carbon support as improved electrocatalysts for ethanol oxidation.

PubMed

Gu, Zhulan; Li, Shumin; Xiong, Zhiping; Xu, Hui; Gao, Fei; Du, Yukou

2018-07-01

Bimetallic nanocatalysts with small particle size benefit from markedly enhanced electrocatalytic activity and stability during small molecule oxidation. Herein, we report a facile method to synthesize binary Pt-Ru nanoparticles dispersed on a carbon support at an optimum temperature. Because of its monodispersed nanostructure, synergistic effects were observed between Pt and Ru and the PtRu/C electrocatalysts showed remarkably enhanced electrocatalytic activity towards ethanol oxidation. The peak current density of the Pt 1 Ru 1 /C electrocatalyst is 3731 mA mg -1 , which is 9.3 times higher than that of commercial Pt/C (401 mA mg -1 ). Furthermore, the synthesized Pt 1 Ru 1 /C catalyst exhibited higher stability during ethanol oxidation in an alkaline medium and maintained a significantly higher current density after successive cyclic voltammograms (CVs) of 500 cycles than commercial Pt/C. Our work highlights the significance of the reaction temperature during electrocatalyst synthesis, leading to enhanced catalytic performance towards ethanol oxidation. The Pt 1 Ru 1 /C electrocatalyst has great potential for application in direct ethanol fuel cells. Copyright © 2018 Elsevier Inc. All rights reserved.

Improving carbon dioxide yields and cell efficiencies for ethanol oxidation by potential scanning

NASA Astrophysics Data System (ADS)

Majidi, Pasha; Pickup, Peter G.

2014-12-01

An ethanol electrolysis cell with aqueous ethanol supplied to the anode and nitrogen at the cathode has been operated under potential cycling conditions in order to increase the yield of carbon dioxide and thereby increase cell efficiency relative to operation at a fixed potential. At ambient temperature, faradaic yields of CO2 as high as 26% have been achieved, while only transient CO2 production was observed at constant potential. Yields increased substantially at higher temperatures, with maximum values at Pt anodes reaching 45% at constant potential and 65% under potential cycling conditions. Use of a PtRu anode increased the cell efficiency by decreasing the anode potential, but this was offset by decreased CO2 yields. Nonetheless, cycling increased the efficiency relative to constant potential. The maximum yields at PtRu and 80 °C were 13% at constant potential and 32% under potential cycling. The increased yields under cycling conditions have been attributed to periodic oxidative stripping of adsorbed CO, which occurs at lower potentials on PtRu than on Pt. These results will be important in the optimization of operating conditions for direct ethanol fuel cells and for the electrolysis of ethanol to produce clean hydrogen.

Synthesis and electrocatalytic activity of Au/Pt bimetallic nanodendrites for ethanol oxidation in alkaline medium.

PubMed

Han, Xinyi; Wang, Dawei; Liu, Dong; Huang, Jianshe; You, Tianyan

2012-02-01

Gold/Platinum (Au/Pt) bimetallic nanodendrites were successfully synthesized through seeded growth method using preformed Au nanodendrites as seeds and ascorbic acid as reductant. Cyclic voltammograms (CVs) of a series of Au/Pt nanodendrites modified electrodes in 1M KOH solution containing 1M ethanol showed that the electrocatalyst with a molar ratio (Au:Pt) of 3 exhibited the highest peak current density and the lowest onset potential. The peak current density of ethanol electro-oxidation on the Au(3)Pt(1) nanodendrites modified glassy carbon electrode (Au(3)Pt(1) electrode) is about 16, 12.5, and 4.5 times higher than those on the polycrystalline Pt electrode, polycrystalline Au electrode, and Au nanodendrites modified glassy carbon electrode (Au dendrites electrode), respectively. The oxidation peak potential of ethanol electro-oxidation on the Au(3)Pt(1) electrode is about 299 and 276 mV lower than those on the polycrystalline Au electrode and Au dendrites electrode, respectively. These results demonstrated that the Au/Pt bimetallic nanodendrites may find potential application in alkaline direct ethanol fuel cells (ADEFCs). Copyright © 2011 Elsevier Inc. All rights reserved.

Efficient xylose fermentation by the brown rot fungus Neolentinus lepideus.

PubMed

Okamoto, Kenji; Kanawaku, Ryuichi; Masumoto, Masaru; Yanase, Hideshi

2012-02-10

The efficient production of bioethanol on an industrial scale requires the use of renewable lignocellulosic biomass as a starting material. A limiting factor in developing efficient processes is identifying microorganisms that are able to effectively ferment xylose, the major pentose sugar found in hemicellulose, and break down carbohydrate polymers without pre-treatment steps. Here, a basidiomycete brown rot fungus was isolated as a new biocatalyst with unprecedented fermentability, as it was capable of converting not only the 6-carbon sugars constituting cellulose, but also the major 5-carbon sugar xylose in hemicelluloses, to ethanol. The fungus was identified as Neolentinus lepideus and was capable of assimilating and fermenting xylose to ethanol in yields of 0.30, 0.33, and 0.34 g of ethanol per g of xylose consumed under aerobic, oxygen-limited, and anaerobic conditions, respectively. A small amount of xylitol was detected as the major by-product of xylose metabolism. N. lepideus produced ethanol from glucose, mannose, galactose, cellobiose, maltose, and lactose with yields ranging from 0.34 to 0.38 g ethanol per g sugar consumed, and also exhibited relatively favorable conversion of non-pretreated starch, xylan, and wheat bran. These results suggest that N. lepideus is a promising candidate for cost-effective and environmentally friendly ethanol production from lignocellulosic biomass. To our knowledge, this is the first report on efficient ethanol fermentation from various carbohydrates, including xylose, by a naturally occurring brown rot fungus. Copyright © 2011 Elsevier Inc. All rights reserved.

Switching the mode of sucrose utilization by Saccharomyces cerevisiae

PubMed Central

Badotti, Fernanda; Dário, Marcelo G; Alves, Sergio L; Cordioli, Maria Luiza A; Miletti, Luiz C; de Araujo, Pedro S; Stambuk, Boris U

2008-01-01

Background Overflow metabolism is an undesirable characteristic of aerobic cultures of Saccharomyces cerevisiae during biomass-directed processes. It results from elevated sugar consumption rates that cause a high substrate conversion to ethanol and other bi-products, severely affecting cell physiology, bioprocess performance, and biomass yields. Fed-batch culture, where sucrose consumption rates are controlled by the external addition of sugar aiming at its low concentrations in the fermentor, is the classical bioprocessing alternative to prevent sugar fermentation by yeasts. However, fed-batch fermentations present drawbacks that could be overcome by simpler batch cultures at relatively high (e.g. 20 g/L) initial sugar concentrations. In this study, a S. cerevisiae strain lacking invertase activity was engineered to transport sucrose into the cells through a low-affinity and low-capacity sucrose-H+ symport activity, and the growth kinetics and biomass yields on sucrose analyzed using simple batch cultures. Results We have deleted from the genome of a S. cerevisiae strain lacking invertase the high-affinity sucrose-H+ symporter encoded by the AGT1 gene. This strain could still grow efficiently on sucrose due to a low-affinity and low-capacity sucrose-H+ symport activity mediated by the MALx1 maltose permeases, and its further intracellular hydrolysis by cytoplasmic maltases. Although sucrose consumption by this engineered yeast strain was slower than with the parental yeast strain, the cells grew efficiently on sucrose due to an increased respiration of the carbon source. Consequently, this engineered yeast strain produced less ethanol and 1.5 to 2 times more biomass when cultivated in simple batch mode using 20 g/L sucrose as the carbon source. Conclusion Higher cell densities during batch cultures on 20 g/L sucrose were achieved by using a S. cerevisiae strain engineered in the sucrose uptake system. Such result was accomplished by effectively reducing sucrose uptake by the yeast cells, avoiding overflow metabolism, with the concomitant reduction in ethanol production. The use of this modified yeast strain in simpler batch culture mode can be a viable option to more complicated traditional sucrose-limited fed-batch cultures for biomass-directed processes of S. cerevisiae. PMID:18304329

Switching the mode of sucrose utilization by Saccharomyces cerevisiae.

PubMed

Badotti, Fernanda; Dário, Marcelo G; Alves, Sergio L; Cordioli, Maria Luiza A; Miletti, Luiz C; de Araujo, Pedro S; Stambuk, Boris U

2008-02-27

Overflow metabolism is an undesirable characteristic of aerobic cultures of Saccharomyces cerevisiae during biomass-directed processes. It results from elevated sugar consumption rates that cause a high substrate conversion to ethanol and other bi-products, severely affecting cell physiology, bioprocess performance, and biomass yields. Fed-batch culture, where sucrose consumption rates are controlled by the external addition of sugar aiming at its low concentrations in the fermentor, is the classical bioprocessing alternative to prevent sugar fermentation by yeasts. However, fed-batch fermentations present drawbacks that could be overcome by simpler batch cultures at relatively high (e.g. 20 g/L) initial sugar concentrations. In this study, a S. cerevisiae strain lacking invertase activity was engineered to transport sucrose into the cells through a low-affinity and low-capacity sucrose-H+ symport activity, and the growth kinetics and biomass yields on sucrose analyzed using simple batch cultures. We have deleted from the genome of a S. cerevisiae strain lacking invertase the high-affinity sucrose-H+ symporter encoded by the AGT1 gene. This strain could still grow efficiently on sucrose due to a low-affinity and low-capacity sucrose-H+ symport activity mediated by the MALx1 maltose permeases, and its further intracellular hydrolysis by cytoplasmic maltases. Although sucrose consumption by this engineered yeast strain was slower than with the parental yeast strain, the cells grew efficiently on sucrose due to an increased respiration of the carbon source. Consequently, this engineered yeast strain produced less ethanol and 1.5 to 2 times more biomass when cultivated in simple batch mode using 20 g/L sucrose as the carbon source. Higher cell densities during batch cultures on 20 g/L sucrose were achieved by using a S. cerevisiae strain engineered in the sucrose uptake system. Such result was accomplished by effectively reducing sucrose uptake by the yeast cells, avoiding overflow metabolism, with the concomitant reduction in ethanol production. The use of this modified yeast strain in simpler batch culture mode can be a viable option to more complicated traditional sucrose-limited fed-batch cultures for biomass-directed processes of S. cerevisiae.

Acetobacter pasteurianus strain AB0220: cultivability and phenotypic stability over 9 years of preservation.

PubMed

Gullo, Maria; Mamlouk, Dhouha; De Vero, Luciana; Giudici, Paolo

2012-06-01

Acetobacter species are members of the α-subclass of Proteobacteria, which harbors a large number of bacteria recalcitrant to cultivation. Strain AB0220 was isolated from a superficial acetification system and preserved for 9 years by short and long time methods. Under short time preservation it was estimated that 540.54 number of generations occurred, whereas in long time preservation conditions the number of generations was 17.40. Ethanol oxidation to acetic acid was stable and confirmed, as well as acetate assimilation during long time preservation. Cultivability checks showed persistence of phenotypic traits (growth on ethanol and methanol, growth on different carbon sources and cellulose production) over the extended preservation time. 16S rRNA gene sequences analysis showed 100 % of similarity with A. pasteurianus (Accession number GQ240636). Stability of subcultures related to the culture age and subcultures frequency, tested by ERIC/PCR, confirmed the suitability of long term preservation at least over a period of 9 years.

Lactic acid production with undefined mixed culture fermentation of potato peel waste.

PubMed

Liang, Shaobo; McDonald, Armando G; Coats, Erik R

2014-11-01

Potato peel waste (PPW) as zero value byproduct generated from food processing plant contains a large quantity of starch, non-starch polysaccharide, lignin, protein, and lipid. PPW as one promising carbon source can be managed and utilized to value added bioproducts through a simple fermentation process using undefined mixed cultures inoculated from wastewater treatment plant sludge. A series of non-pH controlled batch fermentations under different conditions such as pretreatment process, enzymatic hydrolysis, temperature, and solids loading were studied. Lactic acid (LA) was the major product, followed by acetic acid (AA) and ethanol under fermentation conditions without the presence of added hydrolytic enzymes. The maximum yields of LA, AA, and ethanol were respectively, 0.22 g g(-1), 0.06 g g(-1), and 0.05 g g(-1). The highest LA concentration of 14.7 g L(-1) was obtained from a bioreactor with initial solids loading of 60 g L(-1) at 35°C. Copyright © 2014 Elsevier Ltd. All rights reserved.

RNAi assisted genome evolution unveils yeast mutants with improved xylose utilization.

PubMed

HamediRad, Mohammad; Lian, Jiazhang; Li, Hejun; Zhao, Huimin

2018-06-01

Xylose is a major component of lignocellulosic biomass, one of the most abundant feedstocks for biofuel production. Therefore, efficient and rapid conversion of xylose to ethanol is crucial in the viability of lignocellulosic biofuel plants. In this study, RNAi Assisted Genome Evolution (RAGE) was used to improve the xylose utilization rate in SR8, one of the most efficient publicly available xylose utilizing Saccharomyces cerevisiae strains. To identify gene targets for further improvement, we created a genome-scale library consisting of both genetic over-expression and down-regulation mutations in SR8. Followed by screening in media containing xylose as the sole carbon source, yeast mutants with 29% faster xylose utilization, and 45% higher ethanol productivity were obtained relative to the parent strain. Two known and two new effector genes were identified in these mutant strains. Notably, down-regulation of CDC11, an essential gene, resulted in faster xylose utilization, and this gene target cannot be identified in genetic knock-out screens. © 2018 Wiley Periodicals, Inc.

Determine the Requirements for Existing Pipeline, Tank and Terminal Systems to Transport Ethanol without Cracking

DOT National Transportation Integrated Search

2010-06-18

The potential exists for stress corrosion cracking (SCC) of carbon steel pipelines transporting fuel grade ethanol (FGE) and FGE- gasoline blends. The objectives of SCC 4-4 were to: 1. Develop data necessary to make engineering assessments of the fea...

Evaluation of single and stack membraneless enzymatic fuel cells based on ethanol in simulated body fluids.

PubMed

Galindo-de-la-Rosa, J; Arjona, N; Moreno-Zuria, A; Ortiz-Ortega, E; Guerra-Balcázar, M; Ledesma-García, J; Arriaga, L G

2017-06-15

The purpose of this work is to evaluate single and double-cell membraneless microfluidic fuel cells (MMFCs) that operate in the presence of simulated body fluids SBF, human serum and blood enriched with ethanol as fuels. The study was performed using the alcohol dehydrogenase enzyme immobilised by covalent binding through an array composed of carbon Toray paper as support and a layer of poly(methylene blue)/tetrabutylammonium bromide/Nafion and glutaraldehyde (3D bioanode electrode). The single MMFC was tested in a hybrid microfluidic fuel cell using Pt/C as the cathode. A cell voltage of 1.035V and power density of 3.154mWcm -2 were observed, which is the highest performance reported to date. The stability and durability were tested through chronoamperometry and polarisation/performance curves obtained at different days, which demonstrated a slow decrease in the power density on day 10 (14%) and day 20 (26%). Additionally, the cell was tested for ethanol oxidation in simulated body fluid (SBF) with ionic composition similar to human blood plasma. Those tests resulted in 0.93V of cell voltage and a power density close to 1.237mWcm -2 . The double cell MMFC (Stack) was tested using serum and human blood enriched with ethanol. The stack operated with blood in a serial connection showed an excellent cell performance (0.716mWcm -2 ), demonstrating the feasibility of employing human blood as energy source. Copyright © 2017 Elsevier B.V. All rights reserved.

Expression of a codon-optimized β-glucosidase from Cellulomonas flavigena PR-22 in Saccharomyces cerevisiae for bioethanol production from cellobiose.

PubMed

Ríos-Fránquez, Francisco Javier; González-Bautista, Enrique; Ponce-Noyola, Teresa; Ramos-Valdivia, Ana Carmela; Poggi-Varaldo, Héctor Mario; García-Mena, Jaime; Martinez, Alfredo

2017-05-01

Bioethanol is one of the main biofuels produced from the fermentation of saccharified agricultural waste; however, this technology needs to be optimized for profitability. Because the commonly used ethanologenic yeast strains are unable to assimilate cellobiose, several efforts have been made to express cellulose hydrolytic enzymes in these yeasts to produce ethanol from lignocellulose. The C. flavigenabglA gene encoding β-glucosidase catalytic subunit was optimized for preferential codon usage in S. cerevisiae. The optimized gene, cloned into the episomal vector pRGP-1, was expressed, which led to the secretion of an active β-glucosidase in transformants of the S. cerevisiae diploid strain 2-24D. The volumetric and specific extracellular enzymatic activities using pNPG as substrate were 155 IU L -1 and 222 IU g -1 , respectively, as detected in the supernatant of the cultures of the S. cerevisiae RP2-BGL transformant strain growing in cellobiose (20 g L -1 ) as the sole carbon source for 48 h. Ethanol production was 5 g L -1 after 96 h of culture, which represented a yield of 0.41 g g -1 of substrate consumed (12 g L -1 ), equivalent to 76% of the theoretical yield. The S. cerevisiae RP2-BGL strain expressed the β-glucosidase extracellularly and produced ethanol from cellobiose, which makes this microorganism suitable for application in ethanol production processes with saccharified lignocellulose.

Evaluation of feed COD/sulfate ratio as a control criterion for the biological hydrogen sulfide production and lead precipitation.

PubMed

Velasco, Antonio; Ramírez, Martha; Volke-Sepúlveda, Tania; González-Sánchez, Armando; Revah, Sergio

2008-03-01

The ability of sulfate-reducing bacteria to produce hydrogen sulfide and the high affinity of sulfide to react with divalent metallic cations represent an excellent option to remove heavy metals from wastewater. Different parameters have been proposed to control the hydrogen sulfide production by anaerobic bacteria, such as the organic and sulfate loading rates and the feed COD/SO4(2-) ratio. This work relates the feed COD/SO4(2-) ratio with the hydrogen sulfide production and dissolved lead precipitation, using ethanol as carbon and energy source in an up-flow anaerobic sludge blanket reactor. A maximum dissolved sulfide concentration of 470+/-7 mg S/L was obtained at a feed COD/SO4(2-) ratio of 2.5, with sulfate and ethanol conversions of approximately 94 and 87%, respectively. The lowest dissolved sulfide concentration (145+/-10 mg S/L) was observed with a feed COD/SO4(2-) ratio of 0.67. Substantial amounts of acetate (510-1730 mg/L) were produced and accumulated in the bioreactor from ethanol oxidation. Although only incomplete oxidation of ethanol to acetate was observed, the consortium was able to remove 99% of the dissolved lead (200 mg/L) with a feed COD/SO4(2-) ratio of 1.5. It was found that the feed COD/SO4(2-) ratio could be an adequate parameter to control the hydrogen sulfide production and the consequent precipitation of dissolved lead.

Effective immobilization of alcohol dehydrogenase on carbon nanoscaffolds for ethanol biofuel cell.

PubMed

Umasankar, Yogeswaran; Adhikari, Bal-Ram; Chen, Aicheng

2017-12-01

An efficient approach for immobilizing alcohol dehydrogenase (ADH) while enhancing its electron transfer ability has been developed using poly(2-(trimethylamino)ethyl methacrylate) (MADQUAT) cationic polymer and carbon nanoscaffolds. The carbon nanoscaffolds were comprised of single-walled carbon nanotubes (SWCNTs) wrapped with reduced graphene oxide (rGO). The ADH entrapped within the MADQUAT that was present on the carbon nanoscaffolds exhibited a high electron exchange capability with the electrode through its cofactor β-nicotinamide adenine dinucleotide hydrate and β-nicotinamide adenine dinucleotide reduced disodium salt hydrate (NAD + /NADH) redox reaction. The advantages of the carbon nanoscaffolds used as the support matrix and the MADQUAT employed for the entrapment of ADH versus physisorption were demonstrated via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Our experimental results showed a higher electron transfer, electrocatalytic activity, and rate constant for MADQUAT entrapped ADH on the carbon nanoscaffolds. The immobilization of ADH using both MADQUAT and carbon nanoscaffolds exhibited strong potential for the development of an efficient bio-anode for ethanol powered biofuel cells. Copyright © 2017 Elsevier B.V. All rights reserved.

An Electrochemical Gas Biosensor Based on Enzymes Immobilized on Chromatography Paper for Ethanol Vapor Detection.

PubMed

Kuretake, Tatsumi; Kawahara, Shogo; Motooka, Masanobu; Uno, Shigeyasu

2017-02-01

This paper presents a novel method of fabricating an enzymatic biosensor for breath analysis using chromatography paper as enzyme supporting layer and a liquid phase layer on top of screen printed carbon electrodes. We evaluated the performance with ethanol vapor being one of the breathing ingredients. The experimental results show that our sensor is able to measure the concentration of ethanol vapor within the range of 50 to 500 ppm. These results suggest the ability of detecting breath ethanol, and it can possibly be applied as a generic vapor biosensor to a wide range of diseases.

Sulfidogenic fluidized-bed treatment of metal-containing wastewater at low and high temperatures.

PubMed

Sahinkaya, Erkan; Ozkaya, Bestamin; Kaksonen, Anna H; Puhakka, Jaakko A

2007-04-15

The applicability of a fluidized-bed reactor (FBR)-based sulfate reducing bioprocess was investigated for the treatment of iron-containing (40-90 mg/L) acidic wastewater at low (8 degrees C) and high (65 degrees C) temperatures. The FBRs operated at low and high temperatures were inoculated with cultures of sulfate-reducing bacteria (SRB) originally enriched from arctic and hot mining environments, respectively. Ethanol was supplemented as carbon and electron source for SRB. At 8 degrees C, ethanol oxidation and sulfate reduction rates increased steadily and reached 320 and 265 mg/L.day, respectively, after 1 month of operation. After this point, the rates did not change significantly during 130 days of operation. Despite the complete ethanol oxidation and iron precipitation, the average sulfate reduction efficiency was 35 +/- 4% between days 30 and 130 due to the accumulation of acetate. At 65 degrees C, a rapid startup was observed as 99.9, 46, and 29% ethanol, sulfate, acetate removals, in respective order, were observed after 6 days. The feed pH was decreased gradually from its initial value of 6 to around 3.7 during 100 days of operation. The wastewater pH of 4.3-4.4 was neutralized by the alkalinity produced in acetate oxidation and the average effluent pH was 7.8 +/- 0.8. As in the low temperature FBR, acetate accumulated. Hence, the oxidation of acetate is the rate-limiting step in the sulfidogenic ethanol oxidation by thermophilic and psychrotrophic SRB. The sulfate reduction rate is three times and acetate oxidation rate is four times higher at 65 degrees C than at 8 degrees C. (c) 2006 Wiley Periodicals, Inc.

Use of a Tn5-based transposon system to create a cost-effective Zymomonas mobilis for ethanol production from lignocelluloses

PubMed Central

2013-01-01

Background Current methods of ethanol production from lignocelluloses generate a mixture of sugars, primarily glucose and xylose; the fermentation cells are always exposed to stresses like high temperature and low nutritional conditions that affect their growth and productivity. Stress-tolerant strains capable of using both glucose and xylose to produce ethanol with high yield are highly desirable. Results A recombinant Zymomonas mobilis (Z. mobilis) designated as HYMX was constructed by integrating seven genes (Pfu-sHSP, yfdZ, metB, xylA, xylB, tktA and talB) into the genome of Z. mobilis CP4 (CP4) via Tn5 transposon in the present study. The small heat shock protein gene (Pfu-sHSP) from Pyrococcus furious (P. furious) was used to increase the heat-tolerance, the yfdZ and metB genes from E. coli were used to decrease the nutritional requirement. To overcome the bottleneck of CP4 being unable to use pentose, xylose catabolic genes (xylA, xylB, tktA and talB) from E. coli were integrated into CP4 also for construction of the xylose utilizing metabolic pathway. Conclusions The genomic integration confers on Z. mobilis the ability to grow in medium containing xylose as the only carbon source, and to grow in simple chemical defined medium without addition of amino acid. The HYMX demonstrated not only the high tolerance to unfavorable stresses like high temperature and low nutrient, but also the capability of converting both glucose and xylose to ethanol with high yield at high temperature. What’s more, these genetic characteristics were stable up to 100 generations on nonselective medium. Although significant improvements were achieved, yeast extract is needed for ethanol production. PMID:23635356

A dynamic flux balance model and bottleneck identification of glucose, xylose, xylulose co-fermentation in Saccharomyces cerevisiae

USDA-ARS?s Scientific Manuscript database

Economically viable production of lignocellulosic ethanol requires efficient conversion of feedstock sugars to ethanol. Saccharomyces cerevisiae cannot ferment xylose, the main five-carbon sugars in biomass, but can ferment xylulose, an enzymatically derived isomer. Xylulose fermentation is slow rel...

KINETICS OF GROWTH AND ETHANOL PRODUCTION ON DIFFERENT CARBON SUBSTRATES USING GENETICALLY ENGINEERED XYLOSE-FERMENTING YEAST

EPA Science Inventory

Saccharomyces cerevisiae 424A (LNH-ST) strain was used for fermentation of glucose and xylose. Growth kinetics and ethanol productivity were calculated for batch fermentation on media containing different combinations of glucose and xylose to give a final sugar concentra...

Increase in ethanol yield via elimination of lactate production in an ethanol-tolerant mutant of Clostridium thermocellum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biswas, Ranjita; Prabhu, Sandeep; Lynd, Lee R

2014-01-01

Large-scale production of lignocellulosic biofuel is a potential solution to sustainably meet global energy needs. One-step consolidated bioprocessing (CBP) is a potentially advantageous approach for the production of biofuels, but requires an organism capable of hydrolyzing biomass to sugars and fermenting the sugars to ethanol at commercially viable titers and yields. Clostridium thermocellum, a thermophilic anaerobe, can ferment cellulosic biomass to ethanol and organic acids, but low yield, low titer, and ethanol sensitivity remain barriers to industrial production. Here, we deleted the hypoxanthine phosphoribosyltransferase gene in ethanol tolerant strain of C. thermocellum adhE*(EA) in order to allow use of previouslymore » developed gene deletion tools, then deleted lactate dehydrogenase (ldh) to redirect carbon flux towards ethanol. Upon deletion of ldh, the adhE*(EA) ldh strain produced 30% more ethanol than wild type on minimal medium. The adhE*(EA) ldh strain retained tolerance to 5% v/v ethanol, resulting in an ethanol tolerant platform strain of C. thermocellum for future metabolic engineering efforts.« less

The variation of power generation with organic substrates in single-chamber microbial fuel cells (SCMFCs).

PubMed

Sharma, Yogesh; Li, Baikun

2010-03-01

The wastewaters consist of diverse types of organic substrates that can be used as the carbon sources for power generation. To explore the utilization of some of these organics, the electricity generation from three substrates (acetate, ethanol, and glucose) was examined over a concentration range of 0.5-35 mM in single-chamber microbial fuel cells (SCMFCs). The power density generated from glucose was the highest at 401 mW/m(2) followed by acetate and ethanol at 368 mW/m(2) and 302 mW/m(2), respectively. The voltage increased with substrate concentration of 0.5-20mM, but significantly decreased at high substrate concentrations of 20-35 mM. Kinetic analysis indicated that the inhibition in the ethanol-fed MFCs was the highest at the concentration of 35 mM, while inhibition in glucose-fed MFCs was the lowest at the concentration of 20mM. These were in accordance with the extents of voltage decrease at high substrate concentration. Moreover, the effect of the distance between anode and cathode on voltage generation was also investigated. The reduction of the electrode distance by 33% in the glucose-fed MFCs reduced the internal resistance by 73% and led to 20% increase in voltage generation. Published by Elsevier Ltd.

Acetobacter pasteurianus metabolic change induced by initial acetic acid to adapt to acetic acid fermentation conditions.

PubMed

Zheng, Yu; Zhang, Renkuan; Yin, Haisong; Bai, Xiaolei; Chang, Yangang; Xia, Menglei; Wang, Min

2017-09-01

Initial acetic acid can improve the ethanol oxidation rate of acetic acid bacteria for acetic acid fermentation. In this work, Acetobacter pasteurianus was cultured in ethanol-free medium, and energy production was found to increase by 150% through glucose consumption induced by initial acetic acid. However, oxidation of ethanol, instead of glucose, became the main energy production pathway when upon culturing ethanol containing medium. Proteome assay was used to analyze the metabolism change induced by initial acetic acid, which provided insight into carbon metabolic and energy regulation of A. pasteurianus to adapt to acetic acid fermentation conditions. Results were further confirmed by quantitative real-time PCR. In summary, decreased intracellular ATP as a result of initial acetic acid inhibition improved the energy metabolism to produce more energy and thus adapt to the acetic acid fermentation conditions. A. pasteurianus upregulated the expression of enzymes related to TCA and ethanol oxidation to improve the energy metabolism pathway upon the addition of initial acetic acid. However, enzymes involved in the pentose phosphate pathway, the main pathway of glucose metabolism, were downregulated to induce a change in carbon metabolism. Additionally, the enhancement of alcohol dehydrogenase expression promoted ethanol oxidation and strengthened the acetification rate, thereby producing a strong proton motive force that was necessary for energy production and cell tolerance to acetic acid.

Extraction and Esterification of Low-Titer Short-Chain Volatile Fatty Acids from Anaerobic Fermentation with Ionic Liquids.

PubMed

Andersen, Stephen J; Berton, Jan K E T; Naert, Pieter; Gildemyn, Sylvia; Rabaey, Korneel; Stevens, Christian V

2016-08-23

Ionic liquids can both act as a solvent and mediate esterification to valorize low-titer volatile fatty acids and generate organic solvents from renewable carbon sources including biowaste and CO2 . In this study, four phosphonium ionic liquids were tested for single-stage extraction of acetic acid from a dilute stream and esterification to ethyl acetate with added ethanol and heat. The esterification proceeded with a maximum conversion of 85.9±1.3 % after 30 min at 75 °C at a 1:1 stoichiometric ratio of reactants. Extraction and esterification can be tailored using mixed-anion ionic liquids; this is demonstrated herein using a common trihexyl(tetradecyl)phosphonium cation and a mixed chloride and bis(trifluoromethylsulfonyl)imide anion ionic liquid. As a further proof-of-concept, ethyl acetate was generated from an ionic liquid-driven esterification of an acetic acid extractant generated using CO2 as the only carbon source by microbial electrosynthesis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Use of a new Trichoderma harzianum strain isolated from the Amazon rainforest with pretreated sugar cane bagasse for on-site cellulase production.

PubMed

Delabona, Priscila da Silva; Farinas, Cristiane Sanchez; da Silva, Mateus Ribeiro; Azzoni, Sindelia Freitas; Pradella, José Geraldo da Cruz

2012-03-01

The on-site production of cellulases is an important strategy for the development of sustainable second-generation ethanol production processes. This study concerns the use of a specific cellulolytic enzyme complex for hydrolysis of pretreated sugar cane bagasse. Glycosyl hydrolases (FPase, xylanase, and β-glucosidase) were produced using a new strain of Trichoderma harzianum, isolated from the Amazon rainforest and cultivated under different conditions. The influence of the carbon source was first investigated using shake-flask cultures. Selected carbon sources were then further studied under different pH conditions using a stirred tank bioreactor. Enzymatic activities up to 121 FPU/g, 8000 IU/g, and 1730 IU/g of delignified steam-exploded bagasse+sucrose were achieved for cellulase, xylanase and β-glucosidase, respectively. This enzymatic complex was used to hydrolyze pretreated sugar cane bagasse. A comparative evaluation, using an enzymatic extract from Trichoderma reesei RUTC30, indicated similar performance of the T. harzianum enzyme complex, being a potential candidate for on-site production of enzymes. Copyright © 2011 Elsevier Ltd. All rights reserved.

Optimization of metal atomic ratio of PdxRuyNiz on carbon support for ethanol oxidation

NASA Astrophysics Data System (ADS)

Charoen, Kanin; Warakulwit, Chompunuch; Prapainainar, Chaiwat; Seubsai, Anusorn; Chareonpanich, Metta; Prapainainar, Paweena

2017-11-01

The catalytic activity of palladium (Pd) on an alloy catalyst on carbon supports with regards to ethanol oxidation was enhanced by systematically varying the atomic ratio of Pd, ruthenium (Ru), and nickel (Ni) alloy catalyst. Each atomic ratio catalyst was investigated so as to find the highest current density per mass of palladium. Functionalized carbon black (C) and reduced graphene oxide (rGO) were used as carbon supports. The PdxRuyNiz/carbon catalysts were prepared by impregnation and reduction method with sodium borohydride (NaBH4) being used as the reducing agent. Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA) were used to characterize the functionalized carbon supports, and the synthesized PdxRuyNiz/carbon catalysts were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and inductively coupled plasma (ICP). The electrical properties of catalyst were performed by cyclic voltammetry (CV), chronoamperometry (CA), and CO-stripping to investigate the catalytic activity compared to 20%wt synthesized Pd/C. The results showed that Pd:Ru:Ni = 60:0:40 on rGO (Pd60Ni40/rGO) had the best metal atomic ratio and support for the electro-oxidation of ethanol. The maximum current density and the electrochemical surface area were 11,074 mA cm-2 mg-1Pd and 55.6 m2 g-1Pd, which were 1.7 and 2.67 times the corresponding values of synthesized Pd/C, respectively.

Ethanol: A Strategic Energy Source?

DTIC Science & Technology

2009-05-04

needs. The present administration cites our dependence on oil as one of our critical national weaknesses. Our international standing and economic ... stability will improve if we can discover plentiful renewable energy sources that eventually reduce global demand for oil. Ethanol is one of several

A Review of the Potential of Bio-Ethanol in New Zealand

ERIC Educational Resources Information Center

Acharya, Vishesh; Young, Brent R.

2008-01-01

This article presents a study of the techno-economical feasibility of manufacturing biofuel ethanol at small scale from agricultural sources in New Zealand. It investigates possible agricultural products and wastes as potential feedstock and looks at laboratory-scale fermentation trials to determine their ethanol yields. The ethanol requirement to…

A general strategy toward graphitized carbon coating on iron oxides as advanced anodes for lithium-ion batteries.

PubMed

Ding, Chunyan; Zhou, Weiwei; Wang, Bin; Li, Xin; Wang, Dong; Zhang, Yong; Wen, Guangwu

2017-08-25

Integration of carbon materials with benign iron oxides is blazing a trail in constructing high-performance anodes for lithium-ion batteries (LIBs). In this paper, a unique general, simple, and controllable strategy is developed toward in situ uniform coating of iron oxide nanostructures with graphitized carbon (GrC) layers. The basic synthetic procedure only involves a simple dip-coating process for the loading of Ni-containing seeds and a subsequent Ni-catalyzed chemical vapor deposition (CVD) process for the growth of GrC layers. More importantly, the CVD treatment is conducted at a quite low temperature (450 °C) and with extremely facile liquid carbon sources consisting of ethylene glycol (EG) and ethanol (EA). The GrC content of the resulting hybrids can be controllably regulated by altering the amount of carbon sources. The electrochemical results reveal remarkable performance enhancements of iron oxide@GrC hybrids compared with pristine iron oxides in terms of high specific capacity, excellent rate and cycling performance. This can be attributed to the network-like GrC coating, which can improve not only the electronic conductivity but also the structural integrity of iron oxides. Moreover, the lithium storage performance of samples with different GrC contents is measured, manifesting that optimized electrochemical property can be achieved with appropriate carbon content. Additionally, the superiority of GrC coating is demonstrated by the advanced performance of iron oxide@GrC compared with its corresponding counterpart, i.e., iron oxides with amorphous carbon (AmC) coating. All these results indicate the as-proposed protocol of GrC coating may pave the way for iron oxides to be promising anodes for LIBs.

Electro-catalytic activity of multiwall carbon nanotube-metal (Pt or Pd) nanohybrid materials synthesized using microwave-induced reactions and their possible use in fuel cells.

PubMed

V, Lakshman Kumar; Ntim, Susana Addo; Sae-Khow, Ornthida; Janardhana, Chelli; Lakshminarayanan, V; Mitra, Somenath

2012-11-30

Microwave induced reactions for immobilizing platinum and palladium nanoparticles on multiwall carbon nanotubes are presented. The resulting hybrid materials were used as catalysts for direct methanol, ethanol and formic acid oxidation in acidic as well as alkaline media. The electrodes are formed by simply mixing the hybrids with graphite paste, thus using a relatively small quantity of the precious metal. We report Tafel slopes and apparent activation energies at different potentials and temperatures. Ethanol electro-oxidation with the palladium hybrid showed an activation energy of 7.64 kJmol(-1) which is lower than those observed for other systems. This system is economically attractive because Pd is significantly less expensive than Pt and ethanol is fast evolving as a commercial biofuel.

Electro-catalytic activity of multiwall carbon nanotube-metal (Pt or Pd) nanohybrid materials synthesized using microwave-induced reactions and their possible use in fuel cells

PubMed Central

V, Lakshman Kumar; Ntim, Susana Addo; Sae-Khow, Ornthida; Janardhana, Chelli; Lakshminarayanan, V.; Mitra, Somenath

2012-01-01

Microwave induced reactions for immobilizing platinum and palladium nanoparticles on multiwall carbon nanotubes are presented. The resulting hybrid materials were used as catalysts for direct methanol, ethanol and formic acid oxidation in acidic as well as alkaline media. The electrodes are formed by simply mixing the hybrids with graphite paste, thus using a relatively small quantity of the precious metal. We report Tafel slopes and apparent activation energies at different potentials and temperatures. Ethanol electro-oxidation with the palladium hybrid showed an activation energy of 7.64 kJmol−1 which is lower than those observed for other systems. This system is economically attractive because Pd is significantly less expensive than Pt and ethanol is fast evolving as a commercial biofuel. PMID:23118490

Effect of carbon source on the accumulation of cytochrome P-450 in the yeast Saccharomyces cerevisiae.

PubMed

Kärenlampi, S O; Marin, E; Hänninen, O O

1981-02-15

The appearance of cytochrome P-450 in the yeast Saccharomyces cerevisiae depended on the substrate supporting growth. Cytochrome P-450 was apparent in yeast cells grown on a strongly fermentable sugar such as D-glucose, D-fructose or sucrose. When yeast was grown on D-galactose, D-mannose or maltose, where fermentation and respiration occurred concomitantly, cytochrome P-450 was also formed. The cytochrome P-450 concentration was maximal at the beginning of the stationary phase of the culture. Thereafter the concentration decreased, reaching zero at a late-stationary phase. When the yeast was grown on a medium that contained lactose or pentoses (L-arabinose, L-rhamnose, D-ribose and D-xylose), cytochrome P-450 did not occur. When a non-fermentable energy source (glycerol, lactate or ethanol) was used, no cytochrome P-450 was detectable. Transfer of cells from D-glucose medium to ethanol medium caused a slow disappearance of cytochrome P-450, although the amount of the haemoprotein still continued to increase in the control cultures. Cytochrome P-450 appeared thus to accumulate in conditions where the rate of growth was fast and fermentation occurred. Occurrence of this haemoprotein is not necessarily linked, however, with the repression of mitochondrial haemoprotein synthesis.

Morphological Effect of Pd Catalyst on Ethanol Electro-Oxidation Reaction

PubMed Central

Cerritos, Raúl Carrera; Guerra-Balcázar, Minerva; Ramírez, Rosalba Fuentes; Ledesma-García, Janet; Arriaga, Luis Gerardo

2012-01-01

In the present study, three different structures with preferentially exposed crystal faces were supported on commercial carbon black by the polyol method (nanoparticles (NP/C), nanobars (NB/C) and nanorods (NR/C)). The electrocatalysts were characterized by XRD, TEM, TGA and cyclic voltammetry at three different ethanol concentrations. Considerable differences were found in terms of catalytic electroactivity. At all ethanol concentrations, the trend observed for the ethanol oxidation peak potential was preserved as follows: NB/C < NP/C< NR/C < commercial Pd/C. This result indicates that, from a thermodynamics point of view, the NB/C catalyst enclosed by Pd(100) facets presented the highest activity with respect to ethanol electro-oxidation among all of the catalysts studied.

Alcohol-induced one-carbon metabolism impairment promotes dysfunction of DNA base excision repair in adult brain.

PubMed

Fowler, Anna-Kate; Hewetson, Aveline; Agrawal, Rajiv G; Dagda, Marisela; Dagda, Raul; Moaddel, Ruin; Balbo, Silvia; Sanghvi, Mitesh; Chen, Yukun; Hogue, Ryan J; Bergeson, Susan E; Henderson, George I; Kruman, Inna I

2012-12-21

The brain is one of the major targets of chronic alcohol abuse. Yet the fundamental mechanisms underlying alcohol-mediated brain damage remain unclear. The products of alcohol metabolism cause DNA damage, which in conditions of DNA repair dysfunction leads to genomic instability and neural death. We propose that one-carbon metabolism (OCM) impairment associated with long term chronic ethanol intake is a key factor in ethanol-induced neurotoxicity, because OCM provides cells with DNA precursors for DNA repair and methyl groups for DNA methylation, both critical for genomic stability. Using histological (immunohistochemistry and stereological counting) and biochemical assays, we show that 3-week chronic exposure of adult mice to 5% ethanol (Lieber-Decarli diet) results in increased DNA damage, reduced DNA repair, and neuronal death in the brain. These were concomitant with compromised OCM, as evidenced by elevated homocysteine, a marker of OCM dysfunction. We conclude that OCM dysfunction plays a causal role in alcohol-induced genomic instability in the brain because OCM status determines the alcohol effect on DNA damage/repair and genomic stability. Short ethanol exposure, which did not disturb OCM, also did not affect the response to DNA damage, whereas additional OCM disturbance induced by deficiency in a key OCM enzyme, methylenetetrahydrofolate reductase (MTHFR) in Mthfr(+/-) mice, exaggerated the ethanol effect on DNA repair. Thus, the impact of long term ethanol exposure on DNA repair and genomic stability in the brain results from OCM dysfunction, and MTHFR mutations such as Mthfr 677C→T, common in human population, may exaggerate the adverse effects of ethanol on the brain.

Achieving deep cuts in the carbon intensity of U.S. automobile transportation by 2050: complementary roles for electricity and biofuels.

PubMed

Scown, Corinne D; Taptich, Michael; Horvath, Arpad; McKone, Thomas E; Nazaroff, William W

2013-08-20

Passenger cars in the United States (U.S.) rely primarily on petroleum-derived fuels and contribute the majority of U.S. transportation-related greenhouse gas (GHG) emissions. Electricity and biofuels are two promising alternatives for reducing both the carbon intensity of automotive transportation and U.S. reliance on imported oil. However, as standalone solutions, the biofuels option is limited by land availability and the electricity option is limited by market adoption rates and technical challenges. This paper explores potential GHG emissions reductions attainable in the United States through 2050 with a county-level scenario analysis that combines ambitious plug-in hybrid electric vehicle (PHEV) adoption rates with scale-up of cellulosic ethanol production. With PHEVs achieving a 58% share of the passenger car fleet by 2050, phasing out most corn ethanol and limiting cellulosic ethanol feedstocks to sustainably produced crop residues and dedicated crops, we project that the United States could supply the liquid fuels needed for the automobile fleet with an average blend of 80% ethanol (by volume) and 20% gasoline. If electricity for PHEV charging could be supplied by a combination of renewables and natural-gas combined-cycle power plants, the carbon intensity of automotive transport would be 79 g CO2e per vehicle-kilometer traveled, a 71% reduction relative to 2013.

Catalysis for biomass and CO2 use through solar energy: opening new scenarios for a sustainable and low-carbon chemical production.

PubMed

Lanzafame, Paola; Centi, Gabriele; Perathoner, Siglinda

2014-11-21

The use of biomass, bio-waste and CO2 derived raw materials, the latter synthesized using H2 produced using renewable energy sources, opens new scenarios to develop a sustainable and low carbon chemical production, particularly in regions such as Europe lacking in other resources. This tutorial review discusses first this new scenario with the aim to point out, between the different possible options, those more relevant to enable this new future scenario for the chemical production, commenting in particular the different drivers (economic, technological and strategic, environmental and sustainability and socio-political) which guide the selection. The case of the use of non-fossil fuel based raw materials for the sustainable production of light olefins is discussed in more detail, but the production of other olefins and polyolefins, of drop-in intermediates and other platform molecules are also analysed. The final part discusses the role of catalysis in establishing this new scenario, summarizing the development of catalysts with respect to industrial targets, for (i) the production of light olefins by catalytic dehydration of ethanol and by CO2 conversion via FTO process, (ii) the catalytic synthesis of butadiene from ethanol, butanol and butanediols, and (iii) the catalytic synthesis of HMF and its conversion to 2,5-FDCA, adipic acid, caprolactam and 1,6-hexanediol.

Interaction of cytoplasmic dehydrogenases: quantitation of pathways of ethanol metabolism.

PubMed

Vind, C; Grunnet, N

1983-01-01

The interaction between xylitol, alcohol and lactate dehydrogenase has been studied in hepatocytes from rats by applying specifically tritiated substrates. A simple model, describing the metabolic fate of tritium from [2-3H] xylitol and (1R) [1-3H]ethanol is presented. The model allows calculation of the specific radioactivity of free, cytosolic NADH, based on transfer of tritium to lactate, glucose and water. From the initial labelling rate of lactate and the specific radioactivity of cytosolic NADH, we have determined the reversible flow through the lactate dehydrogenase catalyzed reaction to 1-5 mumol/min . g wet wt. The results suggest that xylitol, alcohol and lactate dehydrogenase share the same pool of NAD(H) in the cytoplasma. This finding allows estimation of the ethanol oxidation rate by the non-alcohol dehydrogenase pathways from the relative yield of tritium in water and glucose. The calculations are based on a comparison of the fate of the 1-pro-R hydrogen of ethanol and the hydrogen bound to carbon 2 of xylitol or carbon 2 of lactate under identical conditions.

Use of gas-phase ethanol to mitigate extreme UV/water oxidation of extreme UV optics

NASA Astrophysics Data System (ADS)

Klebanoff, L. E.; Malinowski, M. E.; Clift, W. M.; Steinhaus, C.; Grunow, P.

2004-03-01

A technique is described that uses a gas-phase species to mitigate the oxidation of a Mo/Si multilayer optic caused by either extreme UV (EUV) or electron-induced dissociation of adsorbed water vapor. It is found that introduction of ethanol (EtOH) into a water-rich gas-phase environment inhibits oxidation of the outermost Si layer of the Mo/Si EUV reflective coating. Auger electron spectroscopy, sputter Auger depth profiling, EUV reflectivity, and photocurrent measurements are presented that reveal the EUV/water- and electron/water-derived optic oxidation can be suppressed at the water partial pressures used in the tests (~2×10-7-2×10-5 Torr). The ethanol appears to function differently in two time regimes. At early times, ethanol decomposes on the optic surface, providing reactive carbon atoms that scavenge reactive oxygen atoms before they can oxidize the outermost Si layer. At later times, the reactive carbon atoms form a thin (~5 Å), possibly self-limited, graphitic layer that inhibits water adsorption on the optic surface. .

Initial Observations on the Burning of an Ethanol Droplet in Microgravity

NASA Technical Reports Server (NTRS)

Kazakov, Andrei; Urban, Bradley; Conley, Jordan; Dryer, Frederick L.; Ferkul, Paul (Technical Monitor)

1999-01-01

Combustion of liquid ethanol represents an important system both from fundamental and practical points of view, Ethanol is currently being used as an additive to gasoline in order to reduce carbon monoxide and particulate emissions as well as to improve the fuel octane rating. A detailed physical understanding of liquid ethanol combustion is therefore necessary to achieve an optimal performance of such fuel blends in practical conditions. Ethanol is also a relatively simple model compound suitable for investigation of important combustion characteristics typical of more complex fuels. In particular, ethanol has been proposed for studies of sooting behavior during droplet burning. The sooting nature of ethanol has pressure sensitivities similar to that of n-heptane, but shifted to a higher range of pressures (1-3 atm). Additionally, liquid ethanol is miscible with water produced during its combustion forming mixtures with azeotropic behavior, a phenomenon important for understanding multi-component, liquid fuel combustion. In this work, we present initial results obtained in a series of recent space-based experiments and develop a detailed model describing the burning of ethanol droplet in microgravity.

Optimization of bio-ethanol autothermal reforming and carbon monoxide removal processes

NASA Astrophysics Data System (ADS)

Markova, D.; Bazbauers, G.; Valters, K.; Alhucema Arias, R.; Weuffen, C.; Rochlitz, L.

Experimental investigation of bio-ethanol autothermal reforming (ATR) and water-gas shift (WGS) processes for hydrogen production and regression analysis of the data is performed in the study. The main goal was to obtain regression relations between the most critical dependent variables such as hydrogen, carbon monoxide and methane content in the reformate gas and independent factors such as air-to-fuel ratio (λ), steam-to-carbon ratio (S/C), inlet temperature of reactants into reforming process (T ATRin), pressure (p) and temperature (T ATR) in the ATR reactor from the experimental data. Purpose of the regression models is to provide optimum values of the process factors that give the maximum amount of hydrogen. The experimental ATR system consisted of an evaporator, an ATR reactor and a one-stage WGS reactor. Empirical relations between hydrogen, carbon monoxide, methane content and the controlling parameters downstream of the ATR reactor are shown in the work. The optimization results show that within the considered range of the process factors the maximum hydrogen concentration of 42 dry vol. % and yield of 3.8 mol mol -1 of ethanol downstream of the ATR reactor can be achieved at S/C = 2.5, λ = 0.20-0.23, p = 0.4 bar, T ATRin = 230 °C, T ATR = 640 °C.

PdRu/C catalysts for ethanol oxidation in anion-exchange membrane direct ethanol fuel cells

NASA Astrophysics Data System (ADS)

Ma, Liang; He, Hui; Hsu, Andrew; Chen, Rongrong

2013-11-01

Carbon supported PdRu catalysts with various Pd:Ru atomic ratios were synthesized by impregnation method, and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), electrochemical half-cell tests, and the anion-exchange membrane direct ethanol fuel cell (AEM-DEFC) tests. XRD results suggest that the PdRu metal exists on carbon support in an alloy form. TEM study shows that the bimetallic PdRu/C catalysts have slightly smaller average particle size than the single metal Pd/C catalyst. Lower onset potential and peak potential and much higher steady state current for ethanol oxidation in alkaline media were observed on the bimetallic catalysts (PdxRuy/C) than on the Pd/C, while the activity for ethanol oxidation on the pure Ru/C was not noticeable. By using Pd/C anode catalysts and MnO2 cathode catalysts, AEM-DEFCs free from the expensive Pt catalyst were assembled. The AEM DEFC using the bimetallic Pd3Ru/C anode catalyst showed a peak power density as high as 176 mW cm-2 at 80 °C, about 1.8 times higher than that using the single metal Pd/C catalyst. The role of Ru for enhancing the EOR activity of Pd/C catalysts is discussed.

Optimization of artemisinin extraction from Artemisia annua L. with supercritical carbon dioxide + ethanol using response surface methodology.

PubMed

Ciftci, Ozan Nazim; Cahyadi, Jessica; Guigard, Selma E; Saldaña, Marleny D A

2018-05-13

Malaria is a high priority life-threatening public health concern in developing countries, and therefore there is a growing interest to obtain artemisinin for the production of artemisinin-based combination therapy products. In this study, artemisinin was extracted from the Artemisia annua L. plant using supercritical carbon dioxide (SC-CO 2 ) modified with ethanol. Response surface methodology based on central composite rotatable design was employed to investigate and optimize the extraction conditions of pressure (9.9-30 MPa), temperature (33-67°C), and co-solvent (ethanol, 0-12.6 wt.%). Optimum SC-CO 2 extraction conditions were found to be 30 MPa and 33°C without ethanol. Under optimized conditions, the predicted artemisinin yield was 1.09% whereas the experimental value was 0.71 ± 0.07%. Soxhlet extraction with hexane resulted in higher artemisinin yields and there was no significant difference in the purity of the extracts obtained with SC-CO 2 and Soxhlet extractions. Results indicated that SC-CO 2 and SC-CO 2 +ethanol extraction is a promising alternative for the extraction of artemisinin to eliminate the use of organic solvents, such as hexane, and produce extracts that can be used for the production of antimalarial products. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Spectral studies on nano-sized titania photocatalysts prepared by different drying methods].

PubMed

Ye, Zhao; Zhang, Han-hui; Pan, Hai-bo; Pan, Hong-qing

2002-12-01

Nano-sized TiO2 photocatalysts were prepared by drying the ethanol gel of titanium tetrabutoxide through natural state, supercritical ethanol, supercritical carbon dioxide drying methods and characterized by XRD, FTIR spectroscopy, FT-Raman spectroscopy and fluorescent spectroscopy, respectively. We regard degradation of rhodamine B by photocatalyst as a model reaction, and compare photocatalytic activities of samples obtained. The experimental results show that different drying methods have strong effect on crystal structure, energy band structure, optical adsorption property, surface quality and photocatalytic activity, TiO2 photocatalyst prepared by supercritical carbon dioxide drying method has superior photocatalytic activity.

Hepatoprotective effects of Poly-[hemoglobin-superoxide dismutase-catalase-carbonic anhydrase] on alcohol-damaged primary rat hepatocyte culture in vitro.

PubMed

Jiang, Wenhua; Bian, Yuzhu; Wang, Zhenghui; Chang, Thomas Ming Swi

2017-02-01

We have prepared a novel nanobiotherapeutic, Poly-[hemoglobin-superoxide dismutase-catalase-carbonic anhydrase], which not only transports both oxygen and carbon dioxide but also a therapeutic antioxidant. Our previous study in a severe sustained 90 min hemorrhagic shock rat model shows that it has a hepatoprotective effect. We investigate its hepatoprotective effect further in this present report using an alcohol-damaged primary hepatocyte culture model. Results show that it significantly reduced ethanol-induced AST release, lipid peroxidation, and ROS production in rat primary hepatocytes culture. It also significantly enhanced the viability of ethanol-treated hepatocytes. Thus, the result shows that Poly-[hemoglobin-superoxide dismutase-catalase-carbonic anhydrase] also has some hepatoprotective effects against alcohol-induced injury in in vitro rat primary hepatocytes cell culture. This collaborate our previous observation of its hepatoprotective effect in a severe sustained 90-min hemorrhagic shock rat model.

Phase Partitioning from Theanol Blend Gasolines

EPA Science Inventory

In recent years, the use of ethanol and other alcohols as motor fuel additives has increased. Additionally, ethanol production has expanded due to the potential use of ethanol as a primary fuel source. Historical patterns of gasoline composition show strong dependency on regulato...

Impact of two ionic liquids, 1-ethyl-3-methylimidazolium acetate and 1-ethyl-3-methylimidazolium methylphosphonate, on Saccharomyces cerevisiae: metabolic, physiologic, and morphological investigations.

PubMed

Mehmood, Nasir; Husson, Eric; Jacquard, Cédric; Wewetzer, Sandra; Büchs, Jochen; Sarazin, Catherine; Gosselin, Isabelle

2015-01-01

Ionic liquids (ILs) are considered as suitable candidates for lignocellulosic biomass pretreatment prior enzymatic saccharification and, obviously, for second-generation bioethanol production. However, several reports showed toxic or inhibitory effects of residual ILs on microorganisms, plants, and animal cells which could affect a subsequent enzymatic saccharification and fermentation process. In this context, the impact of two hydrophilic imidazolium-based ILs already used in lignocellulosic biomass pretreatment was investigated: 1-ethyl-3-methylimidazolium acetate [Emim][OAc] and 1-ethyl-3-methylimidazolium methylphosphonate [Emim][MeO(H)PO2]. Their effects were assessed on the model yeast for ethanolic fermentation, Saccharomyces cerevisiae, grown in a culture medium containing glucose as carbon source and various IL concentrations. Classical fermentation parameters were followed: growth, glucose consumption and ethanol production, and two original factors: the respiratory status with the oxygen transfer rate (OTR) and carbon dioxide transfer rate (CTR) of yeasts which were monitored online by respiratory activity monitoring systems (RAMOS). In addition, yeast morphology was characterized by environmental scanning electron microscope (ESEM). The addition of ILs to the growth medium inhibited the OTR and switched the metabolism from respiration (conversion of glucose into biomass) to fermentation (conversion of glucose to ethanol). This behavior could be observed at low IL concentrations (≤5% IL) while above there is no significant growth or ethanol production. The presence of IL in the growth medium also induced changes of yeast morphology, which exhibited wrinkled, softened, and holed shapes. Both ILs showed the same effects, but [Emim][MeO(H)PO2] was more biocompatible than [Emim][OAc] and could be better tolerated by S. cerevisiae. These two imidazolium-derived ILs were appropriate candidates for useful pretreatment of lignocellulosic biomass in the context of second-generation bioethanol production. This fundamental study provides additional information about the toxic effects of ILs. Indeed, the investigations highlighted the better tolerance by S. cerevisiae of [Emim][MeO(H)PO2] than [Emim][OAc].

One-Pot Synthesis of Mesoporous Ni-Ti-Al Ternary Oxides: Highly Active and Selective Catalysts for Steam Reforming of Ethanol.

PubMed

Gonçalves, Alexandre A S; Faustino, Patrícia B; Assaf, José M; Jaroniec, Mietek

2017-02-22

One-pot synthesis of nanostructured ternary oxides of Ni, Al, and Ti was designed and performed via evaporation induced self-assembly (EISA). For the purpose of comparison, analogous oxides were also prepared by the impregnation method. The resulting materials were applied in two catalytic reactions: steam reforming of ethanol (SRE) for H 2 production (subjected to prior activation with H 2 ) and ethanol dehydration (ED; used without prior activation), to in situ analyze carbon accumulation by ethylene depletion when ethanol interacts with acidic sites present on the support. Modification of Ni-Al mixed oxides with titania was shown to have several benefits. CO 2 , NH 3 , and propylamine sorption data indicate a decrease in the strength of acidic and basic sites after addition of titania, which in turn slowed down the carbon accumulation during the ED reaction. These changes in interactions between ethanol and byproducts with the support led to different reaction pathways in SRE, indicating that the catalysts obtained by EISA with titania addition showed higher ethylene selectivity and CO 2 /CO ratios. The opposite was observed for the impregnated catalysts, which were less coke-stable during ED reactions and showed no ethylene selectivity in SRE. Carbon formed during ED reactions was shown to be thermodynamically less favorable and easier to decompose in the presence of titania. All catalysts studied displayed similar and high selectivities (∼80%) and yields (∼5.3 mol H2 /mol ethanol ) toward H 2 , which place them among the most active and selective catalysts for SRE. These results indicate the importance of tailoring the support surface acidity to achieve high reforming performance and higher selectivity toward SRE, one of the key processes to produce cleaner and efficient fuels. For an efficient reforming process, the yield of byproducts is low but still they affect the catalyst stability in the long-run, thus this work may impact future studies toward development of near-zero coke catalysts.

Anti-fouling response of gold-carbon nanotubes composite for enhanced ethanol electrooxidation

NASA Astrophysics Data System (ADS)

Sai Siddhardha, R. S.; Anupam Kumar, Manne; Lakshminarayanan, V.; Ramamurthy, Sai Sathish

2014-12-01

We report the synthesis of gold carbon nanotubes composite through a one-pot surfactant free approach and its utility for ethanol electrooxidation reaction (EOR). The method involves the application of laser ablation for nanoparticle synthesis and simultaneous assembly of these on carbon nanotubes. The catalyst has been characterized by field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDAX) and UV-vis spectroscopic techniques. A systematic study of gold carbon nanotubes modified carbon paste electrode for EOR has been pursued. The kinetic study revealed the excellent stability of the modified electrode even after 200 cycles of EOR and with an Arrhenius energy as low as ∼28 kJ mol-1. Tafel slopes that are the measure of electrode activity have been monitored as a function of temperature of the electrolyte. The results indicate that despite an increase in the reaction rate with temperature, the electrode surface has not been significantly passivated by carbonaceous species produced at high temperatures.

Enhanced adsorption of perfluorooctane sulfonate and perfluorooctanoate by bamboo-derived granular activated carbon.

PubMed

Deng, Shubo; Nie, Yao; Du, Ziwen; Huang, Qian; Meng, Pingping; Wang, Bin; Huang, Jun; Yu, Gang

2015-01-23

A bamboo-derived granular activated carbon with large pores was successfully prepared by KOH activation, and used to remove perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) from aqueous solution. The granular activated carbon prepared at the KOH/C mass ratio of 4 and activation temperature of 900°C had fast and high adsorption for PFOS and PFOA. Their adsorption equilibrium was achieved within 24h, which was attributed to their fast diffusion in the micron-sized pores of activated carbon. This granular activated carbon exhibited the maximum adsorbed amount of 2.32mmol/g for PFOS and 1.15mmol/g for PFOA at pH 5.0, much higher than other granular and powdered activated carbons reported. The activated carbon prepared under the severe activation condition contained many enlarged pores, favorable for the adsorption of PFOS and PFOA. In addition, the spent activated carbon was hardly regenerated in NaOH/NaCl solution, while the regeneration efficiency was significantly enhanced in hot water and methanol/ethanol solution, indicating that hydrophobic interaction was mainly responsible for the adsorption. The regeneration percent was up to 98% using 50% ethanol solution at 45°C. Copyright © 2014 Elsevier B.V. All rights reserved.

Hepatoprotective effects of Arctium lappa Linne on liver injuries induced by chronic ethanol consumption and potentiated by carbon tetrachloride.

PubMed

Lin, Song-Chow; Lin, Chia-Hsien; Lin, Chun-Ching; Lin, Yun-Ho; Chen, Chin-Fa; Chen, I-Cheng; Wang, Li-Ya

2002-01-01

Arctium lappa Linne (burdock) is a perennial herb which is popularly cultivated as a vegetable. In order to evaluate its hepatoprotective effects, a group of rats (n = 10) was fed a liquid ethanol diet (4 g of absolute ethanol/ 80 ml of liquid basal diet) for 28 days and another group (n = 10) received a single intraperitoneal injection of 0.5 ml/kg carbon tetrachloride (CCl(4)) in order to potentiate the liver damage on the 21st day (1 day before the beginning of A. lappa treatment). Control group rats were given a liquid basal diet which did not contain absolute ethanol. When 300 mg/kg A. lappa was administered orally 3 times per day in both the 1-day and 7-day treatment groups, some biochemical and histopathological parameters were significantly altered, both in the ethanol group and the groups receiving ethanol supplemented with CCl(4). A. lappa significantly improved various pathological and biochemical parameters which were worsened by ethanol plus CCl(4)-induced liver damage, such as the ethanol plus CCl(4)-induced decreases in total cytochrome P-450 content and NADPH-cytochrome c reductase activity, increases in serum triglyceride levels and lipid peroxidation (the deleterious peroxidative and toxic malondialdehyde metabolite may be produced in quantity) and elevation of serum transaminase levels. It could even restore the glutathione content and affect the histopathological lesions. These results tended to imply that the hepatotoxicity induced by ethanol and potentiated by CCl(4) could be alleviated with 1 and 7 days of A. lappa treatment. The hepatoprotective mechanism of A. lappa could be attributed, at least in part, to its antioxidative activity, which decreases the oxidative stress of hepatocytes, or to other unknown protective mechanism(s). Copyright 2002 National Science Council, ROC and S. Karger AG, Basel

Denitrification of drinking water in a two-stage membrane bioreactor by using immobilized biomass.

PubMed

Ravnjak, Matjaž; Vrtovšek, Janez; Pintar, Albin

2013-01-01

Nitrate removal from polluted groundwater was investigated in a two-stage anoxic/oxic biofilm membrane bioreactor. The process was carried out with ethanol as a carbon source (corresponding C/N ratio of 1.4-2.5) and commercially available Biocontact-N biocarriers (Nisshinbo, Japan) to enable immobilization of highly efficient and long-lasting microbiota. At a residence time of the liquid phase equal to 2.5h, nitrate conversions higher than 99% were obtained without the formation of nitrite and ammonium ions. The concentration of total organic carbon in the reactor discharge was very similar to the content of organic matter in tap water. The biocarriers minimized the occurrence of suspended filamentous bacteria, and the utilization of increased shear force facilitated collisions of floating biocarrier particles with the outer membrane surface, preventing membrane fouling and resulting in stable operation of the system for 40 days. Copyright © 2012 Elsevier Ltd. All rights reserved.

Butanol formation from gaseous substrates.

PubMed

Dürre, Peter

2016-03-01

Mostly, butanol is formed as a product by saccharolytic anaerobes, employing the so-called ABE fermentation (for acetone-butanol-ethanol). However, this alcohol can also be produced from gaseous substrates such as syn(thesis) gas (major components are carbon monoxide and hydrogen) by autotrophic acetogens. In view of economic considerations, a biotechnological process based on cheap and abundant gases such as CO and CO2 as a carbon source is preferable to more expensive sugar or starch fermentation. In addition, any conflict for use of substrates that can also serve as human nutrition is avoided. Natural formation of butanol has been found with, e.g. Clostridium carboxidivorans, while metabolic engineering for butanol production was successful using, e.g. C. ljungdahlii. Production of butanol from CO2 under photoautotrophic conditions was also possible by recombinant DNA construction of a respective cyanobacterial Synechococcus sp. PCC 7942 strain. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Impact of butyric acid on butanol formation by Clostridium pasteurianum.

PubMed

Regestein, Lars; Doerr, Eric Will; Staaden, Antje; Rehmann, Lars

2015-11-01

The butanol yield of the classic fermentative acetone-butanol-ethanol (ABE) process has been enhanced in the past decades through the development of better strains and advanced process design. Nevertheless, by-product formation and the incomplete conversion of intermediates still decrease the butanol yield. This study demonstrates the potential of increasing the butanol yield from glycerol though the addition of small amounts of butyric acid. The impact of butyric acid was investigated in a 7L stirred tank reactor. The results of this study show the positive impact of butyric acid on butanol yield under pH controlled conditions and the metabolic stages were monitored via online measurement of carbon dioxide formation, pH value and redox potential. Butyric acid could significantly increase the butanol yield at low pH values if sufficient quantities of primary carbon source (glycerol) were present. Copyright © 2015 Elsevier Ltd. All rights reserved.

Incorporating Agricultural Management Practices into the Assessment of Soil Carbon Change and Life-Cycle Greenhouse Gas Emissions of Corn Stover Ethanol Production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qin, Zhangcai; Canter, Christina E.; Dunn, Jennifer B.

Land management practices such as cover crop adoption or manure application that can increase soil organic carbon (SOC) may provide a way to counter SOC loss upon removal of stover from corn fields for use as a biofuel feedstock. This report documents the data, methodology, and assumptions behind the incorporation of land management practices into corn-soybean systems that dominate U.S. grain production using varying levels of stover removal in the GREETTM (Greenhouse gases, Regulated Emissions, and Energy use in Transportation) model and its CCLUB (Carbon Calculator for Land Use change from Biofuels production) module. Tillage (i.e., conventional, reduced and nomore » tillage), corn stover removal (i.e., at 0, 30% and 60% removal rate), and organic matter input techniques (i.e., cover crop and manure application) are included in the analysis as major land management practices. Soil carbon changes associated with land management changes were modeled with a surrogate CENTURY model. The resulting SOC changes were incorporated into CCLUB while GREET was expanded to include energy and material consumption associated with cover crop adoption and manure application. Life-cycle greenhouse gas (GHG) emissions of stover ethanol were estimated using a marginal approach (all burdens and benefits assigned to corn stover ethanol) and an energy allocation approach (burdens and benefits divided between grain and stover ethanol). In the latter case, we considered corn grain and corn stover ethanol to be produced at an integrated facility. Life-cycle GHG emissions of corn stover ethanol are dependent upon the analysis approach selected (marginal versus allocation) and the land management techniques applied. The expansion of CCLUB and GREET to accommodate land management techniques can produce a wide range of results because users can select from multiple scenario options such as choosing tillage levels, stover removal rates, and whether crop yields increase annually or remain constant. In a scenario with conventional tillage and a 30% stover removal rate, life-cycle GHG emissions for a combined gallon of corn grain and stover ethanol without cover crop adoption or manure application are 49 g CO2eq MJ-1, in comparison with 91 g CO2eq MJ-1 for petroleum gasoline. Adopting a cover crop or applying manure reduces the former ethanol life-cycle GHG emissions by 8% and 10%, respectively. We considered two different life cycle analysis approaches to develop estimates of life-cycle GHG emissions for corn stover ethanol, marginal analysis and energy allocation. In the same scenario, this fuel has GHG emissions of 12 – 20 g CO2eq MJ-1 (for manure and cover crop application, respectively) and 45 – 48 g CO2eq MJ-1 with the marginal approach and the energy allocation approach, respectively.« less

Effects of adding ethanol to KOH electrolyte on electrochemical performance of titanium carbide-derived carbon

NASA Astrophysics Data System (ADS)

Xu, Jiang; Zhang, Ruijun; Chen, Peng; Ge, Shanhai

2014-01-01

Porous carbide-derived carbons (CDCs) are synthesized from TiC at different chlorination temperatures as electrode materials for electrochemical capacitors. It is found that the microstructure of the produced CDCs has significant influence on both the hydrophilicity in aqueous KOH electrolyte and the resultant electrochemical performance. Because the TiC-CDC synthesized at higher temperature (e.g. 1000 °C) contains well-ordered graphite ribbons, it shows lower hydrophilicity and specific capacitance. It is also found that addition of a small amount of ethanol to KOH electrolyte effectively improves the wettability of the CDCs synthesized at higher temperature and the corresponding specific capacitance. Compared with the CDC synthesized at 600 °C, the CDC synthesized at 1000 °C shows fast ion transport and excellent capacitive behavior in KOH electrolyte with addition of ethanol because of the existences of mesopores and high specific surface area.

Degradation of palm oil empty fruit bunch (EFB) into bio-oil in sub-and supercritical solvents

NASA Astrophysics Data System (ADS)

Sarwono, Rakhman; Pusfitasari, Eka Dian

2017-01-01

Hydrothemal Liquefaction (HTL) of empty fruit bunch (EFB) of palm oil in different solvents (water, ethanol and hexane) were comparatively investigated. Experiments were carried out in an autoclave in different EFB loading of 9%, 11%, and 13%. The temperature operation was 350 oC, without any catalysts and reaction time of 5 hours. The efficiency of above solvents in terms of conversion rate, soluble liquid and carbon products were found in this experiments. The water solvent gave higher conversion rate of 35 - 36.5 %, while hexane gave conversion of 17 - 25.25 %, and ethanol gave the lower conversion rate of 12.65 - 30.3%, respectively. Increasing the EFB load decreased the conversion rate for ethanol and hexane solvents, for water there are no significant change in the conversion rate. The bio-oil as soluble liquid produced were in order of water, ethanol, and hexane solvents, respectively. The chemical properties of bio-oil products were significantly affected by the type of liquefaction solvent. The compositional of bio-oil consists of mostly of a mixture of organic acids, ketones, and esters. The hexane and ethanol solvents resulted mostly organic acids. In water solvent resulted 2-pentanone, 4-hydroxy-4-methyl and others substances. According to the bio-oil results, organic solvents resulted higher HHV compared to water solvent. The higher heating value (HHV) of the carbon products were also comparatively, ethanol solvent resulted soluble liquid with higher HHV compared to the water solvent.

Evaluation and analysis of Texas biofuel supply chains originating in the United States Midwest and Brazil.

DOT National Transportation Integrated Search

2009-05-01

This 2009 study, funded by the Southwest Region University Transportation Center, investigates : competing ethanol supply chains terminating in the State of Texas. Midwest corn ethanol and : Brazilian sugarcane ethanol constitute two sources of the b...

Engineering Escherichia coli for improved ethanol production from gluconate.

PubMed

Hildebrand, Amanda; Schlacta, Theresa; Warmack, Rebeccah; Kasuga, Takao; Fan, Zhiliang

2013-10-10

We report on engineering Escherichia coli to produce ethanol at high yield from gluconic acid (gluconate). Knocking out genes encoding for the competing pathways (l-lactate dehydrogenase and pyruvate formate lyase A) in E. coli KO11 eliminated lactate production, lowered the carbon flow toward acetate production, and improved the ethanol yield from 87.5% to 97.5% of the theoretical maximum, while the growth rate of the mutant strain was about 70% of the wild type. The corresponding genetic modifications led to a small improvement of ethanol yield from 101.5% to 106.0% on glucose. Deletion of the pyruvate dehydrogenase gene (pdh) alone improved the ethanol yield from 87.5% to 90.4% when gluconate was a substrate. The growth rate of the mutant strain was identical to that of the wild type. The corresponding genetic modification led to no improvements on ethanol yield on glucose. Copyright © 2013 Elsevier B.V. All rights reserved.

Nitrate denitrification with nitrite or nitrous oxide as intermediate products: Stoichiometry, kinetics and dynamics of stable isotope signatures.

PubMed

Vavilin, V A; Rytov, S V

2015-09-01

A kinetic analysis of nitrate denitrification by a single or two species of denitrifying bacteria with glucose or ethanol as a carbon source and nitrite or nitrous oxide as intermediate products was performed using experimental data published earlier (Menyailo and Hungate, 2006; Vidal-Gavilan et al., 2013). Modified Monod kinetics was used in the dynamic biological model. The special equations were added to the common dynamic biological model to describe how isotopic fractionation between N species changes. In contrast to the generally assumed first-order kinetics, in this paper, the traditional Rayleigh equation describing stable nitrogen and oxygen isotope fractionation in nitrate was derived from the dynamic isotopic equations for any type of kinetics. In accordance with the model, in Vidal-Gavilan's experiments, the maximum specific rate of nitrate reduction was proved to be less for ethanol compared to glucose. Conversely, the maximum specific rate of nitrite reduction was proved to be much less for glucose compared to ethanol. Thus, the intermediate nitrite concentration was negligible for the ethanol experiment, while it was significant for the glucose experiment. In Menyailo's and Hungate's experiments, the low value of maximum specific rate of nitrous oxide reduction gives high intermediate value of nitrous oxide concentration. The model showed that the dynamics of nitrogen and oxygen isotope signatures are responding to the biological dynamics. Two microbial species instead of single denitrifying bacteria are proved to be more adequate to describe the total process of nitrate denitrification to dinitrogen. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ethanol and lactic acid production using sap squeezed from old oil palm trunks felled for replanting.

PubMed

Kosugi, Akihiko; Tanaka, Ryohei; Magara, Kengo; Murata, Yoshinori; Arai, Takamitsu; Sulaiman, Othman; Hashim, Rokiah; Hamid, Zubaidah Aimi Abdul; Yahya, Mohd Khairul Azri; Yusof, Mohd Nor Mohd; Ibrahim, Wan Asma; Mori, Yutaka

2010-09-01

Old oil palm trunks that had been felled for replanting were found to contain large quantities of high glucose content sap. Notably, the sap in the inner part of the trunk accounted for more than 80% of the whole trunk weight. The glucose concentration of the sap from the inner part was 85.2g/L and decreased towards the outer part. Other sugars found in relatively low concentrations were sucrose, fructose, galactose, xylose, and rhamnose. In addition, oil palm sap was found to be rich in various kinds of amino acids, organic acids, minerals and vitamins. Based on these findings, we fermented the sap to produce ethanol using the sake brewing yeast strain, Saccharomyces cerevisiae Kyokai no.7. Ethanol was produced from the sap without the addition of nutrients, at a comparable rate and yield to the reference fermentation on YPD medium with glucose as a carbon source. Likewise, we produced lactic acid, a promising material for bio-plastics, poly-lactate, from the sap using the homolactic acid bacterium Lactobacillus lactis ATCC19435. We confirmed that sugars contained in the sap were readily converted to lactic acid with almost the same efficiency as the reference fermentation on MSR medium with glucose as a substrate. These results indicate that oil palm trunks felled for replanting are a significant resource for the production of fuel ethanol and lactic acid in palm oil-producing countries such as Malaysia and Indonesia. Copyright 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Stringent control during carbon starvation of marine Vibrio sp. strain S14: molecular cloning, nucleotide sequence, and deletion of the relA gene.

PubMed Central

Flärdh, K; Axberg, T; Albertson, N H; Kjelleberg, S

1994-01-01

In order to evaluate the role of the stringent response in starvation adaptations of the marine Vibrio sp. strain S14, we have cloned the relA gene and generated relaxed mutants of this organism. The Vibrio relA gene was selected from a chromosomal DNA library by complementation of an Escherichia coli delta relA strain. The nucleotide sequence contains a 743-codon open reading frame that encodes a polypeptide that is identical in length and highly homologous to the E. coli RelA protein. The amino acid sequences are 64% identical, and they share some completely conserved regions. A delta relA::kan allele was generated by replacing 53% of the open reading frame with a kanamycin resistance gene. The Vibrio relA mutants displayed a relaxed control of RNA synthesis and failed to accumulate ppGpp during amino acid limitation. During carbon and energy starvation, a relA-dependent burst of ppGpp synthesis concomitant with carbon source depletion and growth arrest was observed. Also, in the absence of the relA gene, there was an accumulation of ppGpp during carbon starvation, but this was slower and smaller than that which occurred in the stringent strains, and it was preceded by a marked decrease in the [ATP]/[ADP] ratio. In both the wild-type and the relaxed strains, carbon source depletion caused an immediate decrease in the size of the GTP pool and a block of net RNA accumulation. The relA mutation did not affect long-term survival or the development of resistance against heat, ethanol, and oxidative stress during carbon starvation of Vibrio sp. strain S14. PMID:7928955

Organic Compounds Produced by Photolysis of Realistic Interstellar and Cometary Ice Analogs Containing Methanol

NASA Astrophysics Data System (ADS)

Bernstein, Max P.; Sandford, Scott A.; Allamandola, Louis J.; Chang, Sherwood; Scharberg, Maureen A.

1995-11-01

The infrared (IR) spectra of ultraviolet (UV) and thermally processed, methanol-containing interstellar/ cometary ice analogs at temperatures from 12 to 300 K are presented. Infrared spectroscopy, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, and gas chromatography-mass spectrometry indicate that CO (carbon monoxide), CO2 (carbon dioxide), CH4 (methane), HCO (the formyl radical), H2CO (formaldehyde), CH3CH2OH (ethanol), HC(=O)NH2 (formamide), CH3C(=O)NH2 (acetamide), and R-C=-N (nitriles) are formed. In addition, the organic materials remaining after photolyzed ice analogs have been warmed to room temperature contain (in rough order of decreasing abundance), (1) hexamethylenetetramine (HMT, C6H12N4), (2) ethers, alcohols, and compounds related to polyoxymethylene {POM, ( CH2O )n}, and (3) ketones {R-C(=O)-R'} and amides {H2NC(=O)-R}. Most of the carbon in these residues is thought to come from the methanol in the original ice. Deuterium and 13C isotopic labeling demonstrates that methanol is definitely the source of carbon in HMT. High concentrations of HMT in interstellar and cometary ices could have important astrophysical consequences. The ultraviolet photolysis of HMT frozen in H2O ice readily produces the "XCN" band observed in the spectra of protostellar objects and laboratory ices, as well as other nitriles. Thus, HMT may be a precursor of XCN and a source of CN in comets and the interstellar medium. Also, HMT is known to hydrolyze under acidic conditions to yield ammonia, formaldehyde, and amino acids. Thus, HMT may be a significant source of prebiogenic compounds on asteroidal parent bodies. A potential mechanism for the radiative formation of HMT in cosmic ices is outlined.

Biofuel Production Based on Carbohydrates from Both Brown and Red Macroalgae: Recent Developments in Key Biotechnologies

PubMed Central

Kawai, Shigeyuki; Murata, Kousaku

2016-01-01

Marine macroalgae (green, red and brown macroalgae) have attracted attention as an alternative source of renewable biomass for producing both fuels and chemicals due to their high content of suitable carbohydrates and to their advantages over terrestrial biomass. However, except for green macroalgae, which contain relatively easily-fermentable glucans as their major carbohydrates, practical utilization of red and brown macroalgae has been regarded as difficult due to the major carbohydrates (alginate and mannitol of brown macroalgae and 3,6-anhydro-l-galactose of red macroalgae) not being easily fermentable. Recently, several key biotechnologies using microbes have been developed enabling utilization of these brown and red macroalgal carbohydrates as carbon sources for the production of fuels (ethanol). In this review, we focus on these recent developments with emphasis on microbiological biotechnologies. PMID:26861307

Environmental and economic suitability of forest biomass-based bioenergy production in the Southern United States

NASA Astrophysics Data System (ADS)

Dwivedi, Puneet

This study attempts to ascertain the environmental and economic suitability of utilizing forest biomass for cellulosic ethanol production in the Southern United States. The study is divided into six chapters. The first chapter details the background and defines the relevance of the study along with objectives. The second chapter reviews the existing literature to ascertain the present status of various existing conversion technologies. The third chapter assesses the net energy ratio and global warming impact of ethanol produced from slash pine (Pinus elliottii Engelm.) biomass. A life-cycle assessment was applied to achieve the task. The fourth chapter assesses the role of emerging bioenergy and voluntary carbon markets on the profitability of non-industrial private forest (NIPF) landowners by combining the Faustmann and Hartmann models. The fifth chapter assesses perceptions of four stakeholder groups (Non-Government Organization, Academics, Industries, and Government) on the use of forest biomass for bioenergy production in the Southern United States using the SWOT-AHP (Strength, Weakness, Opportunity, and Threat-Analytical Hierarchy Process) technique. Finally, overall conclusions are made in the sixth chapter. Results indicate that currently the production of cellulosic ethanol is limited as the production cost of cellulosic ethanol is higher than the production cost of ethanol derived from corn. However, it is expected that the production cost of cellulosic ethanol will come down in the future from its current level due to ongoing research efforts. The total global warming impact of E85 fuel (production and consumption) was found as 10.44 tons where as global warming impact of an equivalent amount of gasoline (production and consumption) was 21.45 tons. This suggests that the production and use of ethanol derived from slash pine biomass in the form of E85 fuel in an automobile saves about 51% of carbon emissions when compared to gasoline. The net energy ratio of ethanol produced at the mill was found to be 3.2. The unit cost of production of ethanol was estimated to be $2.05 per gasoline gallon energy equivalent. The study also found that the emerging bioenergy and voluntary carbon markets will significantly increase land expectation values and, thus, the profitability of landowners. Results suggest that the optimal rotation age is insensible to alternate management scenarios. Finally, it was found that all stakeholder groups perceive that the overall benefits of forest biomass-based bioenergy development were higher than its weaknesses.

A novel ethanol-tolerant laccase, Tvlac, from Trametes versicolor.

PubMed

Chen, Lei; Yi, Xiaoming; Deng, Fajun; Fang, Wei; Zhang, Xuecheng; Wang, Xiaotang; Fang, Zemin; Xiao, Yazhong

2016-03-01

To produce and characterize novel laccases with ethanol tolerance from Trametes versicolor using agriculture by-products as energy source. Trametes versicolor 1017 produces two laccase isoenzymes with a total activity of 10 U ml(-1) within 8 days when using wheat bran and peanut powder as energy sources in liquid culture medium. A novel isoenzyme, named Tvlac, was identified, purified and characterized. Its optimum pH and temperature were from 4.5 to 5 and 55 to 60 °C, respectively. Its activity was stimulated by ethanol at 10 % (v/v) which increased the V 0. The biochemical properties of Tvlac substantiate the potential of this enzyme for applications under an aqueous ethanol mixture environment.

Temperature and air velocity effects on ethanol emission from corn silage

USDA-ARS?s Scientific Manuscript database

Volatile organic compounds (VOCs) from agricultural sources are believed to be an important contributor to tropospheric ozone in some areas. Recent research suggests that silage is a major source of these VOCs, but only limited data exist on VOC emission from silage. Ethanol is normally the most abu...

Ethanol accumulation during severe drought may signal tree vulnerability to detection and attack by bark beetles

Treesearch

Rick G. Kelsey; D. Gallego; F.J. Sánchez-Garcia; J.A. Pajares

2014-01-01

Tree mortality from temperature-driven drought is occurring in forests around the world, often in conjunction with bark beetle outbreaks when carbon allocation to tree defense declines. Physiological metrics for detecting stressed trees with enhanced vulnerability prior to bark beetle attacks remain elusive. Ethanol, water, monoterpene concentrations, and composition...

Unravelling the influence of carbon dioxide on the adsorptive recovery of butanol from fermentation broth using ITQ-29 and ZIF-8.

PubMed

Martin-Calvo, Ana; Van der Perre, Stijn; Claessens, Benjamin; Calero, Sofia; Denayer, Joeri F M

2018-04-18

The vapor phase adsorption of butanol from ABE fermentation at the head space of the fermenter is an interesting route for the efficient recovery of biobutanol. The presence of gases such as carbon dioxide that are produced during the fermentation process causes a stripping of valuable compounds from the aqueous into the vapor phase. This work studies the effect of the presence of carbon dioxide on the adsorption of butanol at a molecular level. With this aim in mind Monte Carlo simulations were employed to study the adsorption of mixtures containing carbon dioxide, butanol and ethanol. Molecular models for butanol and ethanol that reproduce experimental properties of the molecules such as polarity, vapor-liquid coexistence or liquid density have been developed. Pure component isotherms and heats of adsorption have been computed and compared to experimental data to check the accuracy of the interacting parameters. Adsorption of butanol/ethanol mixtures has been studied in absence and presence of CO2 on two representative materials, a pure silica LTA zeolite and a hydrophobic metal-organic framework ZIF-8. To get a better understanding of the molecular mechanism that governs the adsorption of the targeted mixture in the selected materials, the distribution of the molecules inside the structures was analyzed. The combination of these features allows obtaining a deeper understanding of the process and to identify the role of carbon dioxide in the butanol purification process.

Cocos nucifera Linn. (Palmae) husk fiber ethanolic extract: antioxidant capacity and electrochemical investigation.

PubMed

Oliveira, Monika Bezerra dos Santos; Valentim, Iara Barros; de Vasconcelos, Camila Calado; Omena, Cristhiane Maria Bazílio; Bechara, Etelvino José Henriques; da Costa, João Gomes; Freitas, Mikael de Lima; Sant'Ana, Antônio Euzébio Goulart; Goulart, Marília Oliveira Fonseca

2013-02-01

The present study aims to determine the antioxidant capacity of the ethanolic extracts of husk fiber of four coconut (Cocos nucifera L.) varieties (yellow dwarf, green dwarf, giant and hybrid) and to evaluate the electrochemical behavior of these extracts on a glassy carbon electrode and on a modified glassy carbon electrode. The highest values of total phenolic content were obtained for the hybrid (531 ± 24 mg GAE g(-1) dry extract) and yellow dwarf (501 ± 29 mg GAE g(-1) dry extract) varieties and the lowest was for the green dwarf variety with 58 ± 9 mg GAE g(-1) dry extract. The ability of the extracts to scavenge DPPH˙ radicals was in the order of giant > yellow dwarf > hybrid > green dwarf and the IC50 values varied from 8.6 to 55.9 μg mL(-1). All varieties showed reducing potential by the use of FRAP and CUPRAC methods, with the lowest performance obtained for the green dwarf variety. Additionally, through the use of mimetic biomembranes, ethanolic extracts of coconut husk were shown to protect lipids against oxidative damage independent of the variety. The main antioxidants identified in the extract of yellow dwarf variety by UPLC-MS were quercetin and catechin. Cyclic voltammetric studies of the ethanolic extracts on glassy carbon electrode confirmed the presence of easily oxidized compounds, and the high antioxidant capacity of the varieties. This capacity was expressed as mg quercetin equivalents g(-1) dry extract and ranged from 25.9 up to 53.5 mg QE g(-1). A poly-xanthurenic acid (poly-Xa)/multi-walled carbon nanotube (MWCNT) / glassy carbon modified electrode (poly-Xa/MWCNT/GCE) was used for this purpose. Our findings suggest that these extracts are potentially important antioxidant supplements for the everyday human diet, pharmaceutical and cosmetic industries, thereby aggregating value to the enormous amount of waste from the coconut industry, mostly used for burning purposes.

Cashew apple bagasse as a source of sugars for ethanol production by Kluyveromyces marxianus CE025.

PubMed

Rocha, Maria Valderez Ponte; Rodrigues, Tigressa Helena Soares; Melo, Vania M M; Gonçalves, Luciana R B; de Macedo, Gorete Ribeiro

2011-08-01

The potential of cashew apple bagasse as a source of sugars for ethanol production by Kluyveromyces marxianus CE025 was evaluated in this work. This strain was preliminarily cultivated in a synthetic medium containing glucose and xylose and was able to produce ethanol and xylitol at pH 4.5. Next, cashew apple bagasse hydrolysate (CABH) was prepared by a diluted sulfuric acid pretreatment and used as fermentation media. This hydrolysate is rich in glucose, xylose, and arabinose and contains traces of formic acid and acetic acid. In batch fermentations of CABH at pH 4.5, the strain produced only ethanol. The effects of temperature on the kinetic parameters of ethanol fermentation by K. marxianus CE025 using CABH were also evaluated. Maximum specific growth rate (μ(max)), overall yields of ethanol based on glucose consumption [Formula: see text] and based on glucose + xylose consumption (Y ( P/S )), overall yield of ethanol based on biomass (Y ( P/X )), and ethanol productivity (P (E)) were determined as a function of temperature. Best results of ethanol production were achieved at 30°C, which is also quite close to the optimum temperature for the formation of biomass. The process yielded 12.36 ± 0.06 g l(-1) of ethanol with a volumetric production rate of 0.257 ± 0.002 g l(-1) h(-1) and an ethanol yield of 0.417 ± 0.003 g g(-1) glucose.

EFFECTS OF GESTATIONAL ETHANOL INHALATION ON SENSORY FUNCTION IN RATS.

EPA Science Inventory

Ethanol-blended gasoline entered the market in response to demand for domestic renewable energy sources, which may result in exposure to ethanol vapors in combination with other volatile gasoline constituents. To begin an assessment ofthe risks of exposure to this mixture, we eva...

Ethanol production using engineered mutant E. coli

DOEpatents

Ingram, Lonnie O.; Clark, David P.

1991-01-01

The subject invention concerns novel means and materials for producing ethanol as a fermentation product. Mutant E. coli are transformed with a gene coding for pyruvate decarboxylase activity. The resulting system is capable of producing relatively large amounts of ethanol from a variety of biomass sources.

Production of fuel ethanol from bamboo by concentrated sulfuric acid hydrolysis followed by continuous ethanol fermentation.

PubMed

Sun, Zhao-Yong; Tang, Yue-Qin; Iwanaga, Tomohiro; Sho, Tomohiro; Kida, Kenji

2011-12-01

An efficient process for the production of fuel ethanol from bamboo that consisted of hydrolysis with concentrated sulfuric acid, removal of color compounds, separation of acid and sugar, hydrolysis of oligosaccharides and subsequent continuous ethanol fermentation was developed. The highest sugar recovery efficiency was 81.6% when concentrated sulfuric acid hydrolysis was carried out under the optimum conditions. Continuous separation of acid from the saccharified liquid after removal of color compounds with activated carbon was conducted using an improved simulated moving bed (ISMB) system, and 98.4% of sugar and 90.5% of acid were recovered. After oligosaccharide hydrolysis and pH adjustment, the unsterilized saccharified liquid was subjected to continuous ethanol fermentation using Saccharomycescerevisiae strain KF-7. The ethanol concentration, the fermentation yield based on glucose and the ethanol productivity were approximately 27.2 g/l, 92.0% and 8.2 g/l/h, respectively. These results suggest that the process is effective for production of fuel ethanol from bamboo. Copyright © 2011 Elsevier Ltd. All rights reserved.

Fields of dreams: negotiating an ethanol agenda in the Midwest United States.

PubMed

Gillon, Sean

2010-01-01

Corn ethanol production is central in the United States' agrofuels initiatives. In this paper I discuss corn ethanol production in Iowa, USA and examine several dynamics: farmers' positions in agrofuel supply chains; struggles around the construction and operation of agrofuel refineries; the politics of ethanol production and regulation; and the ecological consequences of increased corn production. I argue that current US agrofuels production and politics reinforce longstanding and unequal political economic relationships in industrial agriculture. I also argue that the politics of US agrofuels, focused on carbon accounting for greenhouse gas reduction and energy security, privilege urban and other actors' social and ecological interests over those of rural places of production.

How to sustainably feed a microbe: Strategies for biological production of carbon-based commodities with renewable electricity

DOE PAGES

Butler, Caitlyn S.; Lovley, Derek R.

2016-11-28

As interest and application of renewable energy grows, strategies are needed to align the asynchronous supply and demand. Microbial metabolisms are a potentially sustainable mechanism for transforming renewable electrical energy into biocommodities that are easily stored and transported. Acetogens and methanogens can reduce carbon dioxide to organic products including methane, acetic acid, and ethanol. The library of biocommodities is expanded when engineered metabolisms of acetogens are included. Typically, electrochemical systems are employed to integrate renewable energy sources with biological systems for production of carbon-based commodities. Within these systems, there are three prevailing mechanisms for delivering electrons to microorganisms for themore » conversion of carbon dioxide to reduce organic compounds: (1) electrons can be delivered to microorganisms via H 2 produced separately in a electrolyzer, (2) H 2 produced at a cathode can convey electrons to microorganisms supported on the cathode surface, and (3) a cathode can directly feed electrons to microorganisms. Each of these strategies has advantages and disadvantages that must be considered in designing full-scale processes. Furthermore, this review considers the evolving understanding of each of these approaches and the state of design for advancing these strategies toward viability.« less

How to sustainably feed a microbe: Strategies for biological production of carbon-based commodities with renewable electricity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butler, Caitlyn S.; Lovley, Derek R.

As interest and application of renewable energy grows, strategies are needed to align the asynchronous supply and demand. Microbial metabolisms are a potentially sustainable mechanism for transforming renewable electrical energy into biocommodities that are easily stored and transported. Acetogens and methanogens can reduce carbon dioxide to organic products including methane, acetic acid, and ethanol. The library of biocommodities is expanded when engineered metabolisms of acetogens are included. Typically, electrochemical systems are employed to integrate renewable energy sources with biological systems for production of carbon-based commodities. Within these systems, there are three prevailing mechanisms for delivering electrons to microorganisms for themore » conversion of carbon dioxide to reduce organic compounds: (1) electrons can be delivered to microorganisms via H 2 produced separately in a electrolyzer, (2) H 2 produced at a cathode can convey electrons to microorganisms supported on the cathode surface, and (3) a cathode can directly feed electrons to microorganisms. Each of these strategies has advantages and disadvantages that must be considered in designing full-scale processes. Furthermore, this review considers the evolving understanding of each of these approaches and the state of design for advancing these strategies toward viability.« less

How to Sustainably Feed a Microbe: Strategies for Biological Production of Carbon-Based Commodities with Renewable Electricity.

PubMed

Butler, Caitlyn S; Lovley, Derek R

2016-01-01

As interest and application of renewable energy grows, strategies are needed to align the asynchronous supply and demand. Microbial metabolisms are a potentially sustainable mechanism for transforming renewable electrical energy into biocommodities that are easily stored and transported. Acetogens and methanogens can reduce carbon dioxide to organic products including methane, acetic acid, and ethanol. The library of biocommodities is expanded when engineered metabolisms of acetogens are included. Typically, electrochemical systems are employed to integrate renewable energy sources with biological systems for production of carbon-based commodities. Within these systems, there are three prevailing mechanisms for delivering electrons to microorganisms for the conversion of carbon dioxide to reduce organic compounds: (1) electrons can be delivered to microorganisms via H 2 produced separately in a electrolyzer, (2) H 2 produced at a cathode can convey electrons to microorganisms supported on the cathode surface, and (3) a cathode can directly feed electrons to microorganisms. Each of these strategies has advantages and disadvantages that must be considered in designing full-scale processes. This review considers the evolving understanding of each of these approaches and the state of design for advancing these strategies toward viability.

Electroreduction of carbon monoxide to liquid fuel on oxide-derived nanocrystalline copper.

PubMed

Li, Christina W; Ciston, Jim; Kanan, Matthew W

2014-04-24

The electrochemical conversion of CO2 and H2O into liquid fuel is ideal for high-density renewable energy storage and could provide an incentive for CO2 capture. However, efficient electrocatalysts for reducing CO2 and its derivatives into a desirable fuel are not available at present. Although many catalysts can reduce CO2 to carbon monoxide (CO), liquid fuel synthesis requires that CO is reduced further, using H2O as a H(+) source. Copper (Cu) is the only known material with an appreciable CO electroreduction activity, but in bulk form its efficiency and selectivity for liquid fuel are far too low for practical use. In particular, H2O reduction to H2 outcompetes CO reduction on Cu electrodes unless extreme overpotentials are applied, at which point gaseous hydrocarbons are the major CO reduction products. Here we show that nanocrystalline Cu prepared from Cu2O ('oxide-derived Cu') produces multi-carbon oxygenates (ethanol, acetate and n-propanol) with up to 57% Faraday efficiency at modest potentials (-0.25 volts to -0.5 volts versus the reversible hydrogen electrode) in CO-saturated alkaline H2O. By comparison, when prepared by traditional vapour condensation, Cu nanoparticles with an average crystallite size similar to that of oxide-derived copper produce nearly exclusive H2 (96% Faraday efficiency) under identical conditions. Our results demonstrate the ability to change the intrinsic catalytic properties of Cu for this notoriously difficult reaction by growing interconnected nanocrystallites from the constrained environment of an oxide lattice. The selectivity for oxygenates, with ethanol as the major product, demonstrates the feasibility of a two-step conversion of CO2 to liquid fuel that could be powered by renewable electricity.

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

PubMed Central

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

The effect of carbon-chain oxygenation in the carbon-carbon dissociation.

PubMed

Dos Santos, Lisandra Paulino; Baptista, Leonardo

2018-06-01

Currently, there is a trend of moving away from the use of fossil fuels to the use of biofuels. This modification changes the molecular structure of gasoline and diesel constituents, which should impact pollutant emissions and engine efficiency. An important property of automotive fuels is the resistance to autoignition. The goal of the present work is to evaluate thermochemical and kinetic parameters that govern the carbon-carbon bond dissociation and relate these parameters, in conjunction with molecular properties, to autoignition resistance. Three model reactions were investigated in the present work: dissociation of ethane, ethanol, and ethanal. All studies were conducted at the multiconfigurational level of theory, and the rate coefficients were evaluated from 300 to 2000 K. The comparison of dissociation energies and Arrhenius expressions indicates that autoignition resistance is related to the kinetic control of dissociation reactions and it is possible to relate the higher octane number of ethanol based fuels to the kinetics parameters of carbon-carbon bond fission. Graphical abstract Effect of the functional group in the Arrhenius parameters of the C-C dissociation. Arrhenius curves calculated at NEVPT2(6,6)/6-311G(2df,2pd).

Optimization of a corn steep medium for production of ethanol from synthesis gas fermentation by Clostridium ragsdalei.

PubMed

Saxena, Jyotisna; Tanner, Ralph S

2012-04-01

Fermentation of biomass derived synthesis gas to ethanol is a sustainable approach that can provide more usable energy and environmental benefits than food-based biofuels. The effects of various medium components on ethanol production by Clostridium ragsdalei utilizing syngas components (CO:CO(2)) were investigated, and corn steep liquor (CSL) was used as an inexpensive nutrient source for ethanol production by C. ragsdalei. Elimination of Mg(2+), NH(4) (+) and PO(4) (3-) decreased ethanol production from 38 to 3.7, 23 and 5.93 mM, respectively. Eliminating Na(+), Ca(2+), and K(+) or increasing Ca(2+), Mg(2+), K(+), NH(4) (+) and PO(4) (3-) concentrations had no effect on ethanol production. However, increased Na(+) concentration (171 mM) inhibited growth and ethanol production. Yeast extract (0.5 g l(-1)) and trace metals were necessary for growth of C. ragsdalei. CSL alone did not support growth and ethanol production. Nutrients limiting in CSL were trace metals, NH(4) (+) and reducing agent (Cys: cysteine sulfide). Supplementation of trace metals, NH(4) (+) and CyS to CSL (20 g l(-1), wet weight basis) yielded better growth and similar ethanol production as compared to control medium. Using 10 g l(-1), the nutritional limitation led to reduced ethanol production. Higher concentrations of CSL (50 and 100 g l(-1)) were inhibitory for cell growth and ethanol production. The CSL could replace yeast extract, vitamins and minerals (excluding NH(4) (+)). The optimized CSL medium produced 120 and 50 mM of ethanol and acetate, respectively. The CSL could provide as an inexpensive source of most of the nutrients required for the syngas fermentation, and thus could improve the economics of ethanol production from biomass derived synthesis gas by C. ragsdalei.

Preparation and emission characteristics of ethanol-diesel fuel blends.

PubMed

Zhang, Run-Duo; He, Hong; Shi, Xiao-Yan; Zhang, Chang-Bin; He, Bang-Quan; Wang, Jian-Xin

2004-01-01

The preparation of ethanol-diesel fuel blends and their emission characteristics were investigated. Results showed the absolute ethanol can dissolve in diesel fuel at an arbitrary ratio and a small quantity of water(0.2%) addition can lead to the phase separation of blends. An organic additive was synthesized and it can develop the ability of resistance to water and maintain the stability of ethanol-diesel-trace amounts of water system. The emission characteristics of 10%, 20%, and 30% ethanol-diesel fuel blends, with or without additives, were compared with those of diesel fuel in a direct injection (DI) diesel engine. The experimental results indicated that the blend of ethanol with diesel fuel significantly reduced the concentrations of smoke, hydrocarbon (HC), and carbon monoxide (CO) in exhaust gas. Using 20% ethanol-diesel fuel blend with the additive of 2% of the total volume, the optimum mixing ratio was achieved, at which the bench diesel engine testing showed a significant decrease in exhaust gas. Bosch smoke number was reduced by 55%, HC emission by 70%, and CO emission by 45%, at 13 kW/1540 r/min. However, ethanol-diesel fuel blends produced a few ppm acetaldehydes and more ethanol in exhaust gas.

The market and environmental effects of alternative biofuel policies

NASA Astrophysics Data System (ADS)

Drabik, Dusan

This dissertation analyzes market and environmental effects of alternative U.S. and Brazilian biofuel policies. Although we focus on corn- and sugarcane-ethanol, the advanced analytical framework can easily be extended to other biofuels and biofuel feedstocks, such as biodiesel and soybean. The dissertation consists of three chapters. The first chapter develops an analytical framework to assess the market effects of a set of biofuel policies (including subsidies to feedstocks). U.S. corn-ethanol policies are used as an example to study the effects of biofuel policies on corn prices. We determine the 'no policy' ethanol price, analyze the implications for the 'no policy' corn price and resulting 'water' in the ethanol price premium due to the policy, and generalize the surprising interaction effects between mandates and tax credits to include ethanol and corn production subsidies. The effect of an ethanol price premium depends on the value of the ethanol co-product, the value of production subsidies, and how the world ethanol price is determined. U.S. corn-ethanol policies are shown to be a major reason for recent rises in corn prices. The ethanol policy-induced increase in corn prices is estimated to be 33 -- 46.5 percent in the period 2008 -- 2011. The second chapter seeks to answer the question of what caused the significant increase in ethanol, sugar, and sugarcane prices in Brazil in the period 2010/11 to 2011/12. We develop a general economic model of the Brazilian fuel-ethanol-sugar complex. Unlike biofuel mandates and tax exemptions elsewhere, Brazil's fuel-ethanol-sugar markets and fuel policies are unique in that each policy, in this setting, theoretically has an ambiguous impact on the market price of ethanol and hence on sugarcane and sugar prices. Our empirical analysis shows that there are two policies that seemingly help the ethanol industry but do otherwise in reality: a low gasoline tax and a high anhydrous tax exemption result in lower ethanol prices. On the other hand, as expected, higher mandates, gasoline prices, and tax exemptions for hydrous ethanol lead to higher ethanol and sugar prices. Eliminating Brazilian ethanol tax exemptions and mandates reduces ethanol prices by 21 percent in 2010-11, which is very similar to the estimated effects of U.S. ethanol policies in the same time period. However, the marginal changes in Brazilian policies on ethanol prices between 2010-11 and 2011-12 are small both individually and collectively. The observed market changes can only be explained by outward shifts in fuel transportation and sugar export demand curves, and reduced sugarcane supply due to bad weather. In the third chapter, we investigate whether U.S. corn ethanol saves greenhouse gas emissions relative to the gasoline it is assumed to replace one-to-one (on an energy equivalent basis). This chapter shows that ethanol policies generate far greater carbon leakage in the fuel market than in the agricultural market, where leakage occurs in the form of land use change. Carbon leakage in the fuel market due to a tax credit is always greater than that of a mandate, while the combination of a mandate and subsidy generates greater leakage than a mandate alone. We show that corn-ethanol does not meet the U.S. EPA's sustainability threshold, regardless of the biofuel policy and whether one includes emissions from land use change. This result makes the controversy over how to measure land use change inconsequential.

Ethanol flame synthesis of carbon nanotubes in deficient oxygen environments

NASA Astrophysics Data System (ADS)

Hu, Wei-Chieh; Lin, Ta-Hui

2016-04-01

In this study, carbon nanotubes (CNTs) were synthesized using ethanol diffusion flames in a stagnation-flow system composed of an upper oxidizer duct and a lower liquid pool. In the experiments, a gaseous mixture of oxygen and nitrogen flowed from the upper oxidizer duct, and then impinged onto the vertically aligned ethanol pool to generate a planar and steady diffusion flame in a deficient oxygen environment. A nascent nickel mesh was used as the catalytic metal substrate to collect deposited materials. The effect of low oxygen concentration on the formation of CNTs was explored. The oxygen concentration significantly influenced the flame environment and thus the synthesized carbon products. Lowering the oxygen concentration increased the yield, diameter, and uniformity of CNTs. The optimal operating conditions for CNT synthesis were an oxygen concentration in the range of 15%-19%, a flame temperature in the range of 460 °C-870 °C, and a sampling position of 0.5-1 mm below the upper edge of the blue flame front. It is noteworthy that the concentration gradient of C2 species and CO governed the CNT growth directly. CNTs were successfully fabricated in regions with uniform C2 species and CO distributions.

Nickel-based anode with water storage capability to mitigate carbon deposition for direct ethanol solid oxide fuel cells.

PubMed

Wang, Wei; Su, Chao; Ran, Ran; Zhao, Bote; Shao, Zongping; Tade, Moses O; Liu, Shaomin

2014-06-01

The potential to use ethanol as a fuel places solid oxide fuel cells (SOFCs) as a sustainable technology for clean energy delivery because of the renewable features of ethanol versus hydrogen. In this work, we developed a new class of anode catalyst exemplified by Ni+BaZr0.4Ce0.4Y0.2O3 (Ni+BZCY) with a water storage capability to overcome the persistent problem of carbon deposition. Ni+BZCY performed very well in catalytic efficiency, water storage capability and coking resistance tests. A stable and high power output was well maintained with a peak power density of 750 mW cm(-2) at 750 °C. The SOFC with the new robust anode performed for seven days without any sign of performance decay, whereas SOFCs with conventional anodes failed in less than 2 h because of significant carbon deposition. Our findings indicate the potential applications of these water storage cermets as catalysts in hydrocarbon reforming and as anodes for SOFCs that operate directly on hydrocarbons. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A facile synthesis of palladium nanoparticles supported on functional carbon nanotubes and its novel catalysis for ethanol electrooxidation.

PubMed

Chen, Xiao-mei; Lin, Zhi-jie; Jia, Tian-tian; Cai, Zhi-min; Huang, Xiao-li; Jiang, Ya-qi; Chen, Xi; Chen, Guo-nan

2009-09-14

In this study, a novel material, palladium nanoparticles-carboxylic functional carbon nanotubes (PdNPs-CFCNTs), based on PdNPs supported on CFCNTs was synthesized by a facile spontaneous redox method. The material reveals high electrochemical activity and excellent catalytic characteristic for alcohol electrooxidation on a glassy carbon electrode (GCE) in an alkaline medium. The preparation mechanism was studied by the galvanic cell effect between PdCl(4)(2-) and functional defect sites on CFCNTs. Results from UV-visible absorption spectroscopy and electrochemical impedance spectroscopy revealed that the reduction of PdCl(4)(2-) to metallic Pd was successfully achieved. Morphologies of PdNPs supporting on CFCNTs (PdNPs-CFCNTs) were also characterized by transmission electron micrograph. PdNPs-CFCNTs with the best electrocatalytic characteristics were obtained under the condition as: the weight ratio of Pd to CFCNTs was kept at 2:1, the temperature was kept at 70 degrees C in the synthesis, and the scan rate of the applied potential was selected at 60 mV s(-1). The results indicate that PdNPs-CFCNTs could be a great potential material in direct ethanol fuel cells and ethanol sensors.

Changes of trehalose content and expression of relative genes during the bioethanol fermentation by Saccharomyces cerevisiae.

PubMed

Yi, Chenfeng; Wang, Fenglian; Dong, Shijun; Li, Hao

2016-10-01

Traditionally, trehalose is considered as a protectant to improve the ethanol tolerance of Saccharomyces cerevisiae. In this study, to clarify the changes and roles of trehalose during the bioethanol fermentation, trehalose content and expression of related genes at lag, exponential, and stationary phases (i.e., 2, 8, and 16 h of batch fermentation process) were determined. Although yeast cells at exponential and stationary phase had higher trehalose content than cells at lag phase (P < 0.01), there was no significant difference in trehalose content between exponential and stationary phases (P > 0.05). Moreover, expression of the trehalose degradation-related genes NTH1 and NTH2 decreased at exponential phase in comparison with that at lag phase; compared with cells at lag phase, cells at stationary phase had higher expression of TPS1, ATH1, NTH1, and NTH2 but lower expression of TPS2. During the lag-exponential phase transition, downregulation of NTH1 and NTH2 promoted accumulation of trehalose, and to some extent, trehalose might confer ethanol tolerance to S. cerevisiae before stationary phase. During the exponential-stationary phase transition, upregulation of TPS1 contributed to accumulation of trehalose, and Tps1 protein might be indispensable in yeast cells to withstand ethanol stress at the stationary phase. Moreover, trehalose would be degraded to supply carbon source at stationary phase.

Growth and metabolic profiling of the novel thermophilic bacterium Thermoanaerobacter sp. strain YS13.

PubMed

Peng, Tingting; Pan, Siyi; Christopher, Lew P; Sparling, Richard; Levin, David B

2016-09-01

A strictly anaerobic, thermophilic bacterium, designated strain YS13, was isolated from a geothermal hot spring. Phylogenetic analysis using the 16S rRNA genes and cpn60 UT genes suggested strain YS13 as a species of Thermoanaerobacter. Using cellobiose or xylose as carbon source, YS13 was able to grow over a wide range of temperatures (45-70 °C), and pHs (pH 5.0-9.0), with optimum growth at 65 °C and pH 7.0. Metabolic profiling on cellobiose, glucose, or xylose in 1191 medium showed that H2, CO2, ethanol, acetate, and lactate were the major metabolites. Lactate was the predominant end product from glucose or cellobiose fermentations, whereas H2 and acetate were the dominant end products from xylose fermentation. The metabolic balance shifted away from ethanol to H2, acetate, and lactate when YS13 was grown on cellobiose as temperatures increased from 45 to 70 °C. When YS13 was grown on xylose, a metabolic shift from lactate to H2, CO2, and acetate was observed in cultures as the temperature of incubation increased from 45 to 65 °C, whereas a shift from ethanol and CO2 to H2, acetate, and lactate was observed in cultures incubated at 70 °C.

Comparative transcriptome analysis of Methylibium petroleiphilum PM1 exposed to the fuel oxygenates methyl tert-butyl ether and ethanol.

PubMed

Hristova, Krassimira R; Schmidt, Radomir; Chakicherla, Anu Y; Legler, Tina C; Wu, Janice; Chain, Patrick S; Scow, Kate M; Kane, Staci R

2007-11-01

High-density whole-genome cDNA microarrays were used to investigate substrate-dependent gene expression of Methylibium petroleiphilum PM1, one of the best-characterized aerobic methyl tert-butyl ether (MTBE)-degrading bacteria. Differential gene expression profiling was conducted with PM1 grown on MTBE and ethanol as sole carbon sources. Based on microarray high scores and protein similarity analysis, an MTBE regulon located on the megaplasmid was identified for further investigation. Putative functions for enzymes encoded in this regulon are described with relevance to the predicted MTBE degradation pathway. A new unique dioxygenase enzyme system that carries out the hydroxylation of tert-butyl alcohol to 2-methyl-2-hydroxy-1-propanol in M. petroleiphilum PM1 was discovered. Hypotheses regarding the acquisition and evolution of MTBE genes as well as the involvement of IS elements in these complex processes were formulated. The pathways for toluene, phenol, and alkane oxidation via toluene monooxygenase, phenol hydroxylase, and propane monooxygenase, respectively, were upregulated in MTBE-grown cells compared to ethanol-grown cells. Four out of nine putative cyclohexanone monooxygenases were also upregulated in MTBE-grown cells. The expression data allowed prediction of several hitherto-unknown enzymes of the upper MTBE degradation pathway in M. petroleiphilum PM1 and aided our understanding of the regulation of metabolic processes that may occur in response to pollutant mixtures and perturbations in the environment.

Cellulase enzyme: Homology modeling, binding site identification and molecular docking

NASA Astrophysics Data System (ADS)

Selvam, K.; Senbagam, D.; Selvankumar, T.; Sudhakar, C.; Kamala-Kannan, S.; Senthilkumar, B.; Govarthanan, M.

2017-12-01

Cellulase is an enzyme that degrades the linear polysaccharide like cellulose into glucose by breaking the β-1,4- glycosidic bonds. These enzymes are the third largest enzymes with a great potential towards the ethanol production and play a vital role in degrading the biomass. The production of ethanol depends upon the ability of the cellulose to utilize the wide range of substrates. In this study, the 3D structure of cellulase from Acinetobacter sp. was modeled by using Modeler 9v9 and validated by Ramachandran plot. The accuracy of the predicted 3D structure was checked using Ramachandran plot analysis showed that 81.1% in the favored region, compatibility of an atomic model (3D) with amino acid sequence (1D) for the model was observed as 78.21% and 49.395% for Verify 3D and ERRAT at SAVES server. As the binding efficacy with the substrate might suggests the choice of the substrate as carbon and nitrogen sources, the cellobiose, cellotetraose, cellotetriose and laminaribiose were employed in the docking studies. The docking of cellobiose, cellotetraose, cellotetriose and laminaribiose with cellulase exhibited the binding energy of -6.1523 kJ/mol, -7.8759 kJ/mol,-6.1590 kJ/mol and -6.7185 kJ/mol, respectively. These docking studies revealed that cellulase has the greater potential towards the cellotetraose as a substrate for the high yield of ethanol.

Isolation and characterization of ethanol tolerant yeast strains

PubMed Central

Tikka, Chiranjeevi; Osuru, Hari Prasad; Atluri, Navya; Raghavulu, Praveen Chakravarthi Veera; yellapu, Nanda Kumar; Mannur, Ismail Shaik; Prasad, Uppu Venkateswara; Aluru, Sudheer; K, Narasimha Varma; Bhaskar, Matcha

2013-01-01

Yeast strains are commonly associated with sugar rich environments. Various fruit samples were selected as source for isolating yeast cells. The isolated cultures were identified at Genus level by colony morphology, biochemical characteristics and cell morphological characters. An attempt has been made to check the viability of yeast cells under different concentrations of ethanol. Ethanol tolerance of each strain was studied by allowing the yeast to grow in liquid YEPD (Yeast Extract Peptone Dextrose) medium having different concentrations of ethanol. A total of fifteen yeast strains isolated from different samples were used for the study. Seven strains of Saccharomyces cerevisiae obtained from different fruit sources were screened for ethanol tolerance. The results obtained in this study show a range of tolerance levels between 7%-12% in all the stains. Further, the cluster analysis based on 22 RAPD (Random Amplified polymorphic DNA) bands revealed polymorphisms in these seven Saccharomyces strains. PMID:23750092

Effective depolymerization of concentrated acid hydrolysis lignin using a carbon-supported ruthenium catalyst in ethanol/formic acid media.

PubMed

Kristianto, Ivan; Limarta, Susan Olivia; Lee, Hyunjoo; Ha, Jeong-Myeong; Suh, Dong Jin; Jae, Jungho

2017-06-01

Lignin isolated by two-step concentrated acid hydrolysis of empty fruit bunch (EFB) was effectively depolymerized into a high-quality bio-oil using formic acid (FA) as an in-situ hydrogen source and Ru/C as a catalyst in supercritical ethanol. A bio-oil yield of 66.3wt% with an average molecular weight of 822g/mol and an aromatic monomer content of 6.1wt% was achieved at 350°C and a FA-to-lignin mass ratio of 3 after a reaction time of 60min. The combination of Ru/C and FA also resulted in a significant reduction in the oxygen content of the bio-oil by ∼60% and a corresponding increase in the higher heating value (HHV) to 32.7MJ/kg due to the enhanced hydrodeoxygenation activity. An examination of the FA decomposition characteristics revealed that Ru/C provides a greater increase in the rate of hydrogen production from FA, explaining the efficient depolymerization of lignin in a combined system. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biosynthesis, characterization and enzymatic transesterification of single cell oil of Mucor circinelloides--a sustainable pathway for biofuel production.

PubMed

Carvalho, Ana K F; Rivaldi, Juan D; Barbosa, Jayne C; de Castro, Heizir F

2015-04-01

The filamentous fungus Mucor circinelloides URM 4182 was tested to determine its ability to produce single-cell oil suitable for obtaining biodiesel. Cell growth and lipid accumulation were investigated in a medium containing glucose as the main carbon source. A microwave-assisted ethanol extraction technique (microwave power ⩽200 W, 50-60 °C) was established and applied to lipid extraction from the fungal hyphae to obtain high lipid concentration (44%wt) of the dry biomass, which was considerably higher than the quantity obtained by classical solvent methods. The lipid profile showed a considerable amount of oleic acid (39.3%wt), palmitic acid (22.2%wt) and γ-linoleic acid (10.8%wt). Biodiesel was produced by transesterification of the single-cell oil with ethanol using a immobilized lipase from Candida antarctica (Novozym® 435) as the catalyst. (1)H NMR and HPLC analyses confirmed conversion of 93% of the single-cell oil from M. circinelloides into ethyl esters (FAEE). Copyright © 2015 Elsevier Ltd. All rights reserved.

Development of industrial brewing yeast with low acetaldehyde production and improved flavor stability.

PubMed

Wang, Jinjing; Shen, Nan; Yin, Hua; Liu, Chunfeng; Li, Yongxian; Li, Qi

2013-02-01

Higher acetaldehyde concentration in beer is one of the main concerns of current beer industry in China. Acetaldehyde is always synthesized during beer brewing by the metabolism of yeast. Here, using ethanol as the sole carbon source and 4-methylpyrazole as the selection marker, we constructed a new mutant strain with lower acetaldehyde production and improved ethanol tolerance via traditional mutagenesis strategy. European Brewery Convention tube fermentation tests comparing the fermentation broths of mutant strain and industrial brewing strain showed that the acetaldehyde concentration of mutant strain was 81.67 % lower, whereas its resistant staling value was 1.0-fold higher. Owing to the mutation, the alcohol dehydrogenase activity of the mutant strain decreased to about 30 % of the wild-type strain. In the meantime, the fermentation performance of the newly screened strain has little difference compared with the wild-type strain, and there are no safety problems regarding the industrial usage of the mutant strain. Therefore, we suggest that the newly screened strain could be directly applied to brewing industry.

Cellulase production using different streams of wheat grain- and wheat straw-based ethanol processes.

PubMed

Gyalai-Korpos, Miklós; Mangel, Réka; Alvira, Pablo; Dienes, Dóra; Ballesteros, Mercedes; Réczey, Kati

2011-07-01

Pretreatment is a necessary step in the biomass-to-ethanol conversion process. The side stream of the pretreatment step is the liquid fraction, also referred to as the hydrolyzate, which arises after the separation of the pretreated solid and is composed of valuable carbohydrates along with compounds that are potentially toxic to microbes (mainly furfural, acetic acid, and formic acid). The aim of our study was to utilize the liquid fraction from steam-exploded wheat straw as a carbon source for cellulase production by Trichoderma reesei RUT C30. Results showed that without detoxification, the fungus failed to utilize any dilution of the hydrolyzate; however, after a two-step detoxification process, it was able to grow on a fourfold dilution of the treated liquid fraction. Supplementation of the fourfold-diluted, treated liquid fraction with washed pretreated wheat straw or ground wheat grain led to enhanced cellulase (filter paper) activity. Produced enzymes were tested in hydrolysis of washed pretreated wheat straw. Supplementation with ground wheat grain provided a more efficient enzyme mixture for the hydrolysis by means of the near-doubled β-glucosidase activity obtained.

The greenhouse gas intensity and potential biofuel production capacity of maize stover harvest in the US Midwest

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, Curtis D.; Zhang, Xuesong; Reddy, Ashwan D.

Agricultural residues are important sources of feedstock for a cellulosic biofuels industry that is being developed to reduce greenhouse gas emissions and improve energy independence. While the US Midwest has been recognized as key to providing maize stover for meeting near-term cellulosic biofuel production goals, there is uncertainty that such feedstocks can produce biofuels that meet federal cellulosic standards. Here, we conducted extensive site-level calibration of the Environmental Policy Integrated Climate (EPIC) terrestrial ecosystems model and applied the model at high spatial resolution across the US Midwest to improve estimates of the maximum production potential and greenhouse gas emissions expectedmore » from continuous maize residue-derived biofuels. A comparison of methodologies for calculating the soil carbon impacts of residue harvesting demonstrates the large impact of study duration, depth of soil considered, and inclusion of litter carbon in soil carbon change calculations on the estimated greenhouse gas intensity of maize stover-derived biofuels. Using the most representative methodology for assessing long-term residue harvesting impacts, we estimate that only 5.3 billion liters per year (bly) of ethanol, or 8.7% of the near-term US cellulosic biofuel demand, could be met under common no-till farming practices. However, appreciably more feedstock becomes available at modestly higher emissions levels, with potential for 89.0 bly of ethanol production meeting US advanced biofuel standards. Adjustments to management practices, such as adding cover crops to no-till management, will be required to produce sufficient quantities of residue meeting the greenhouse gas emission reduction standard for cellulosic biofuels. Considering the rapid increase in residue availability with modest relaxations in GHG reduction level, it is expected that management practices with modest benefits to soil carbon would allow considerable expansion of potential cellulosic biofuel production.« less

Cross-Selectivity Enhancement of Poly(vinylidene fluoride-hexafluoropropylene)-Based Sensor Arrays for Detecting Acetone and Ethanol.

PubMed

Daneshkhah, Ali; Shrestha, Sudhir; Siegel, Amanda; Varahramyan, Kody; Agarwal, Mangilal

2017-03-15

Two methods for cross-selectivity enhancement of porous poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP)/carbon black (CB) composite-based resistive sensors are provided. The sensors are tested with acetone and ethanol in the presence of humid air. Cross-selectivity is enhanced using two different methods to modify the basic response of the PVDF-HFP/CB sensing platform. In method I, the adsorption properties of PVDF-HFP/CB are altered by adding a polyethylene oxide (PEO) layer or by treating with infrared (IR). In method II, the effects of the interaction of acetone and ethanol are enhanced by adding diethylene carbonate (DEC) or PEO dispersed in DEC (PEO/DEC) to the film. The results suggest the approaches used in method I alter the composite ability to adsorb acetone and ethanol, while in method II, they alter the transduction characteristics of the composite. Using these approaches, sensor relative response to acetone was increased by 89% compared with the PVDF-HFP/CB untreated film, whereas sensor relative response to ethanol could be decreased by 57% or increased by 197%. Not only do these results demonstrate facile methods for increasing sensitivity of PVDF-HFP/CB film, used in parallel they demonstrate a roadmap for enhancing system cross-selectivity that can be applied to separate units on an array. Fabrication methods, experimental procedures and results are presented and discussed.

Cross-Selectivity Enhancement of Poly(vinylidene fluoride-hexafluoropropylene)-Based Sensor Arrays for Detecting Acetone and Ethanol

PubMed Central

Daneshkhah, Ali; Shrestha, Sudhir; Siegel, Amanda; Varahramyan, Kody; Agarwal, Mangilal

2017-01-01

Two methods for cross-selectivity enhancement of porous poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP)/carbon black (CB) composite-based resistive sensors are provided. The sensors are tested with acetone and ethanol in the presence of humid air. Cross-selectivity is enhanced using two different methods to modify the basic response of the PVDF-HFP/CB sensing platform. In method I, the adsorption properties of PVDF-HFP/CB are altered by adding a polyethylene oxide (PEO) layer or by treating with infrared (IR). In method II, the effects of the interaction of acetone and ethanol are enhanced by adding diethylene carbonate (DEC) or PEO dispersed in DEC (PEO/DEC) to the film. The results suggest the approaches used in method I alter the composite ability to adsorb acetone and ethanol, while in method II, they alter the transduction characteristics of the composite. Using these approaches, sensor relative response to acetone was increased by 89% compared with the PVDF-HFP/CB untreated film, whereas sensor relative response to ethanol could be decreased by 57% or increased by 197%. Not only do these results demonstrate facile methods for increasing sensitivity of PVDF-HFP/CB film, used in parallel they demonstrate a roadmap for enhancing system cross-selectivity that can be applied to separate units on an array. Fabrication methods, experimental procedures and results are presented and discussed. PMID:28294961

Alkaline direct ethanol fuel cell performance using alkali-impregnated polyvinyl alcohol/functionalized carbon nano-tube solid electrolytes

NASA Astrophysics Data System (ADS)

Huang, Chien-Yi; Lin, Jia-Shiun; Pan, Wen-Han; Shih, Chao-Ming; Liu, Ying-Ling; Lue, Shingjiang Jessie

2016-01-01

This study investigates the application of a polyvinyl alcohol (PVA)/functionalized carbon nano-tubes (m-CNTs) composite in alkaline direct ethanol fuel cells (ADEFC). The m-CNTs are functionalized with PVA using the ozone mediation method, and the PVA composite containing the modified CNTs is prepared. Adding m-CNT into the PVA matrix enhances the alkaline uptake and the ionic conductivity of the KOH-doped electrolyte. Meanwhile, the m-CNT-containing membrane exhibited a lower swelling ratio and suppressed ethanol permeability compared to the pristine PVA film. The optimal condition for the ADEFC is determined to be under operation at an anode feed of 3 M ethanol in a 5 M KOH solution (at a flow rate of 5 cm3 min-1) with a cathode feed of moisturized oxygen (with a flow rate of 100 cm3 min-1) and the KOH-doped PVA/m-CNT electrolyte. We achieved a peak power density value of 65 mW cm-2 at 60 °C, which is the highest among the ADEFC literature data and several times higher than the proton-exchange direct ethanol fuel cells using sulfonated membrane electrolytes. Therefore, the KOH-doped PVA/m-CNT electrolyte is a suitable solid electrolyte for ADEFCs and has potential for commercialization in alkaline fuel cell applications.

Reviving the carbohydrate economy via multi-product lignocellulose biorefineries.

PubMed

Zhang, Y-H Percival

2008-05-01

Before the industrial revolution, the global economy was largely based on living carbon from plants. Now the economy is mainly dependent on fossil fuels (dead carbon). Biomass is the only sustainable bioresource that can provide sufficient transportation fuels and renewable materials at the same time. Cellulosic ethanol production from less costly and most abundant lignocellulose is confronted with three main obstacles: (1) high processing costs (dollars /gallon of ethanol), (2) huge capital investment (dollars approximately 4-10/gallon of annual ethanol production capacity), and (3) a narrow margin between feedstock and product prices. Both lignocellulose fractionation technology and effective co-utilization of acetic acid, lignin and hemicellulose will be vital to the realization of profitable lignocellulose biorefineries, since co-product revenues would increase the margin up to 6.2-fold, where all purified lignocellulose co-components have higher selling prices (> approximately 1.0/kg) than ethanol ( approximately 0.5/kg of ethanol). Isolation of large amounts of lignocellulose components through lignocellulose fractionation would stimulate R&D in lignin and hemicellulose applications, as well as promote new markets for lignin- and hemicellulose-derivative products. Lignocellulose resource would be sufficient to replace significant fractionations (e.g., 30%) of transportation fuels through liquid biofuels, internal combustion engines in the short term, and would provide 100% transportation fuels by sugar-hydrogen-fuel cell systems in the long term.

Characteristics and performance of lanthanum gallate electrolyte-supported SOFC under ethanol steam and hydrogen

NASA Astrophysics Data System (ADS)

Huang, Bo; Zhu, Xin-Jian; Hu, Wan-Qi; Yu, Qing-Chun; Tu, Heng-Yong

This study is focused on the electrochemical performance of perovskite-type materials based on doped LaGaO 3. La 0.8Sr 0.2Ga 0.8Mg 0.2O 3- δ (LSGM) and La 0.8Sr 0.2Ga 0.8Mg 0.115Co 0.085O 3- δ (LSGMC) were used as electrolytes and (Pr 0.7Ca 0.3) 0.9MnO 3 (PCM) and La 0.75Sr 0.25Cr 0.5Mn 0.5O 3- δ (LSCM) as cathode and anode material, respectively. LSGM and LSGMC electrolytes were prepared by tape casting with a thickness of about 600 μm. The performance of LSCM/LSGMC/PCM was slightly superior to that obtained on LSCM/LSGM/PCM at different temperatures in both humidified hydrogen and ethanol steam atmospheres, good values of power output in LSCM/LSGMC/PCM were 182 and 169 mW cm -2 using humidified hydrogen and ethanol steam as fuel, respectively, and oxygen as oxidant at 850 °C. Cell stability tests indicate no significant degradation in performance after 60 h of cell testing when LSCM anode was exposed to ethanol steam at 750 °C. Almost no carbon deposits were detected after testing in ethanol steam at 750 °C for >60 h on the LSCM anodes, suggesting that carbon deposition was limited during cell operation.

Biobutanol production by Clostridium acetobutylicum using xylose recovered from birch Kraft black liquor.

PubMed

Kudahettige-Nilsson, Rasika L; Helmerius, Jonas; Nilsson, Robert T; Sjöblom, Magnus; Hodge, David B; Rova, Ulrika

2015-01-01

Acetone-butanol-ethanol (ABE) fermentation was studied using acid-hydrolyzed xylan recovered from hardwood Kraft black liquor by CO2 acidification as the only carbon source. Detoxification of hydrolyzate using activated carbon was conducted to evaluate the impact of inhibitor removal and fermentation. Xylose hydrolysis yields as high as 18.4% were demonstrated at the highest severity hydrolysis condition. Detoxification using active carbon was effective for removal of both phenolics (76-81%) and HMF (38-52%). Batch fermentation of the hydrolyzate and semi-defined P2 media resulted in a total solvent yield of 0.12-0.13g/g and 0.34g/g, corresponding to a butanol concentration of 1.8-2.1g/L and 7.3g/L respectively. This work is the first study of a process for the production of a biologically-derived biofuel from hemicelluloses solubilized during Kraft pulping and demonstrates the feasibility of utilizing xylan recovered directly from industrial Kraft pulping liquors as a feedstock for biological production of biofuels such as butanol. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Costs of Pelleting to Enhance the Logistics of Distillers Grains Shipping

USDA-ARS?s Scientific Manuscript database

Biofuels, especially corn-based ethanol, can help meet some of the increasing demand for transportation fuels. Currently, the most heavily utilized substrate is corn grain, which is readily converted into ethanol at a relatively low cost compared to other biomass sources. The production of ethanol...

Neurophysiological Assessment of Auditory, Peripheral Nerve, Somatosensory, and Visual System Functions after Developmental Exposure to Ethanol Vapors

EPA Science Inventory

Ethanol-blended gasoline entered the market in response to demand for domestic renewable energy sources, and may result in increased inhalation of ethanol vapors in combination with other volatile gasoline constituents. It is important to understand potential risks of inhalation ...

Chem I Supplement: Effects of Ethanol on Nutrition.

ERIC Educational Resources Information Center

Shorey, RoseAnn L.

1979-01-01

Malnutrition due to alcoholism is discussed. It includes energy from the metabolism of ethanol as it contributes to obesity, the replacement of nutritious foods by sources of ethanol, inhibition of vitamins being activated, the increase in excretion of valuable minerals, and toxicity to cells of organ systems. (Author/SA)

Nanoporous palladium anode for direct ethanol solid oxide fuel cells with nanoscale proton-conducting ceramic electrolyte

NASA Astrophysics Data System (ADS)

Li, Yong; Wong, Lai Mun; Xie, Hanlin; Wang, Shijie; Su, Pei-Chen

2017-02-01

In this work, we demonstrate the operation of micro-solid oxide fuel cells (μ-SOFCs) with nanoscale proton-conducting Y-BaZrO3 (BZY) electrolyte to avoid the fuel crossover problem for direct ethanol fuel cells (DEFCs). The μ-SOFCs are operated with the direct utilisation of ethanol vapour as a fuel and Pd as anode at the temperature range of 300-400 °C. The nanoporous Pd anode is achieved by DC sputtering at high Ar pressure of 80 mTorr. The Pd-anode/BYZ-electrolyte/Pt-cathode cell show peak power densities of 72.4 mW/cm2 using hydrogen and 15.3 mW/cm2 using ethanol at 400 °C. No obvious carbon deposition is seen from XPS analysis after fuel cell test with ethanol fuel.

Fuel ethanol from raw corn

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weller, C.L.; Rodda, E.D.; Steinberg, M.P.

Crude amylase preparations were produced by growing Aspergillus awamori and A. niger on raw ground whole corn. These Koji preparations were used to hydrolyze the starch of raw ground whole corn to sugars during simultaneous fermentation of the sugars to ethanol by distillers active dry yeast. Ethanol concentrations of the fermentation beers were determined with gas-chromatography. These fermentations yielded an average of 89.6% theoretical ethanol compared to control, conventional, fermentations that had an average of 89.8%. Carbon dioxide evolutions were determined with use of Alwood valves. Both the Koji and conventional fermentations produced an average of 0.48 gram of carbonmore » dioxide per gram of dry substrate starch within 72 hours. However, initially the conventional fermentation rate was greater. Koji dehydrated at 41 degrees C had no apparent detrimental effects on theoretical ethanol yield.« less

Fuel ethanol from raw corn

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weller, C.L.; Rodda, E.D.; Steinberg, M.P.

Crude amylase preparations were produced by growing Aspergillus awamori and A. niger on raw ground whole corn. These Koji preparations were used to hydrolyze the starch of raw ground whole corn to sugars during simultaneous fermentation of the sugars to ethanol by distillers active dry yeast. Ethanol concentrations of the fermentation beers were determined with gas-chromatography. These fermentations yielded an average of 89.6% theoretical ethanol compared to control, conventional, fermentations that had an average of 89.8%. Carbon dioxide evolutions were determined with use of Alwood valves. Both the Koji and conventional fermentations produced an average of 0.48 gram of carbonmore » dioxide per gram of dry substrate starch within 72 hours. However, initially the conventional fermentation rate was greater. Koji dehydrated at 41/sup 0/C had no apparent detrimental effects on theoretical ethanol yield.« less

Detoxification and fermentation of pyrolytic sugar for ethanol production.

PubMed

Wang, Hui; Livingston, Darrell; Srinivasan, Radhakrishnan; Li, Qi; Steele, Philip; Yu, Fei

2012-11-01

The sugars present in bio-oil produced by fast pyrolysis can potentially be fermented by microbial organisms to produce cellulosic ethanol. This study shows the potential for microbial digestion of the aqueous fraction of bio-oil in an enrichment medium to consume glucose and produce ethanol. In addition to glucose, inhibitors such as furans and phenols are present in the bio-oil. A pure glucose enrichment medium of 20 g/l was used as a standard to compare with glucose and aqueous fraction mixtures for digestion. Thirty percent by volume of aqueous fraction in media was the maximum additive amount that could be consumed and converted to ethanol. Inhibitors were removed by extraction, activated carbon, air stripping, and microbial methods. After economic analysis, the cost of ethanol using an inexpensive fermentation medium in a large scale plant is approximately $14 per gallon.

Integration of succinic acid and ethanol production within a corn or barley biorefinery

USDA-ARS?s Scientific Manuscript database

Production of succinic acid from glucose by Escherichia coli strain AFP184 was studied in a batch fermentor. The bases used for pH control included NaOH, KOH, NH4OH, and Na2CO3. The yield of succinic acid without and with carbon dioxide supplied by an adjacent ethanol fermentor using either corn or ...

Capture of carbon dioxide from ethanol fermentation by liquid absorption for use in biological production of succinic acid

USDA-ARS?s Scientific Manuscript database

Previously it was shown that the gas produced in an ethanol fermentor using either corn or barley as feedstock could be sparged directly into an adjacent fermentor using Escherichia coli AFP184 to provide the CO2 required for succinic acid production. In the present investigation it has been demons...

Modified Ni-Cu catalysts for ethanol steam reforming

NASA Astrophysics Data System (ADS)

Dan, M.; Mihet, M.; Almasan, V.; Borodi, G.; Katona, G.; Muresan, L.; Lazar, M. D.

2013-11-01

Three Ni-Cu catalysts, having different Cu content, supported on γ-alumina were synthesized by wet co-impregnation method, characterized and tested in the ethanol steam reforming (ESR) reaction. The catalysts were characterized for determination of: total surface area and porosity (N2 adsorption - desorption using BET and Dollimer Heal methods), Ni surface area (hydrogen chemisorption), crystallinity and Ni crystallites size (X-Ray Diffraction), type of catalytic active centers (Hydrogen Temperature Programmed Reduction). Total surface area and Ni crystallites size are not significantly influenced by the addition of Cu, while Ni surface area is drastically diminished by increasing of Cu concentration. Steam reforming experiments were performed at atmospheric pressure, temperature range 150-350°C, and ethanol - water molar ration of 1 at 30, using Ar as carrier gas. Ethanol conversion and hydrogen production increase by the addition of Cu. At 350°C there is a direct connection between hydrogen production and Cu concentration. Catalysts deactivation in 24h time on stream was studied by Transmission Electron Microscopy (TEM) and temperature-programmed reduction (TPR) on used catalysts. Coke deposition was observed at all studied temperatures; at 150°C amorphous carbon was evidenced, while at 350°C crystalline, filamentous carbon is formed.

Market penetration of biodiesel and ethanol

NASA Astrophysics Data System (ADS)

Szulczyk, Kenneth Ray

This dissertation examines the influence that economic and technological factors have on the penetration of biodiesel and ethanol into the transportation fuels market. This dissertation focuses on four aspects. The first involves the influence of fossil fuel prices, because biofuels are substitutes and have to compete in price. The second involves biofuel manufacturing technology, principally the feedstock-to-biofuel conversion rates, and the biofuel manufacturing costs. The third involves prices for greenhouse gas offsets. The fourth involves the agricultural commodity markets for feedstocks, and biofuel byproducts. This dissertation uses the Forest and Agricultural Sector Optimization Model-Greenhouse Gas (FASOM-GHG) to quantitatively examine these issues and calculates equilibrium prices and quantities, given market interactions, fossil fuel prices, carbon dioxide equivalent prices, government biofuel subsidies, technological improvement, and crop yield gains. The results indicate that for the ranges studied, gasoline prices have a major impact on aggregate ethanol production but only at low prices. At higher prices, one runs into a capacity constraint that limits expansion on the capacity of ethanol production. Aggregate biodiesel production is highly responsive to gasoline prices and increases over time. (Diesel fuel price is proportional to the gasoline price). Carbon dioxide equivalent prices expand the biodiesel industry, but have no impact on ethanol aggregate production when gasoline prices are high again because of refinery capacity expansion. Improvement of crop yields shows a similar pattern, expanding ethanol production when the gasoline price is low and expanding biodiesel. Technological improvement, where biorefinery production costs decrease over time, had minimal impact on aggregate ethanol and biodiesel production. Finally, U.S. government subsidies have a large expansionary impact on aggregate biodiesel production. Finally, U.S. government subsidies have a large expansionary impact on aggregate biodiesel production, but only expand the ethanol industry at low gasoline prices. All of these factors increase agricultural welfare with most expanding producer surplus and mixed effects on consumers.

Regulated and unregulated emissions from an internal combustion engine operating on ethanol-containing fuels

NASA Astrophysics Data System (ADS)

Poulopoulos, S. G.; Samaras, D. P.; Philippopoulos, C. J.

In the present work, the effect of ethanol addition to gasoline on regulated and unregulated emissions is studied. A 4-cylinder OPEL 1.6 L internal combustion engine equipped with a hydraulic brake dynamometer was used in all the experiments. For exhaust emissions treatment a typical three-way catalyst was used. Among the various compounds detected in exhaust emissions, the following ones were monitored at engine and catalyst outlet: methane, hexane, ethylene, acetaldehyde, acetone, benzene, 1,3-butadiene, toluene, acetic acid and ethanol. Addition of ethanol in the fuel up to 10% w/w had as a result an increase in the Reid vapour pressure of the fuel, which indicates indirectly increased evaporative emissions, while carbon monoxide tailpipe emissions were decreased. For ethanol-containing fuels, acetaldehyde emissions were appreciably increased (up to 100%), especially for fuel containing 3% w/w ethanol. In contrast, aromatics emissions were decreased by ethanol addition to gasoline. Methane and ethanol were the most resistant compounds to oxidation while ethylene was the most degradable compound over the catalyst. Ethylene, methane and acetaldehyde were the main compounds present at engine exhaust while methane, acetaldehyde and ethanol were the main compounds in tailpipe emissions for ethanol fuels after the catalyst operation.

Dietary fat sources differentially modulate intestinal barrier and hepatic inflammation in alcohol-induced liver injury in rats

PubMed Central

Zhong, Wei; Li, Qiong; Xie, Guoxiang; Sun, Xiuhua; Tan, Xiaobing; Sun, Xinguo; Jia, Wei

2013-01-01

Endotoxemia is a causal factor in the development of alcoholic liver injury. The present study aimed at determining the interactions of ethanol with different fat sources at the gut-liver axis. Male Sprague-Dawley rats were pair fed control or ethanol liquid diet for 8 wk. The liquid diets were based on a modified Lieber-DeCarli formula, with 30% total calories derived from corn oil (rich in polyunsaturated fatty acids). To test the effects of saturated fats, corn oil in the ethanol diet was replaced by either cocoa butter (CB, rich in long-chain saturated fatty acids) or medium-chain triglycerides (MCT, exclusively medium-chain saturated fatty acids). Ethanol feeding increased hepatic lipid accumulation and inflammatory cell infiltration and perturbed hepatic and serum metabolite profiles. Ethanol feeding with CB or MCT alleviated ethanol-induced liver injury and attenuated ethanol-induced metabolic perturbation. Both CB and MCT also normalized ethanol-induced hepatic macrophage activation, cytokine expression, and neutrophil infiltration. Ethanol feeding elevated serum endotoxin level, which was normalized by MCT but not CB. In accordance, ethanol-induced downregulations of intestinal occludin and zonula occludens-1 were normalized by MCT but not CB. However, CB normalized ethanol-increased hepatic endotoxin level in association with upregulation of an endotoxin detoxifying enzyme, argininosuccinate synthase 1 (ASS1). Knockdown ASS1 in H4IIEC3 cells resulted in impaired endotoxin clearance and upregulated cytokine expression. These data demonstrate that the protection of saturated fats against alcohol-induced liver injury occur via different actions at the gut-liver axis and are chain length dependent. PMID:24113767

A cheap and non-destructive approach to increase coverage/loading of hydrophilic hydroxide on hydrophobic carbon for lightweight and high-performance supercapacitors.

PubMed

Zhang, Liuyang; Gong, Hao

2015-12-08

Carbon-based substrates offer unprecedented advantages in lightweight supercapacitors. However, it is still challenging to achieve high coverage or loading. Different from the traditional belief that a lack of defects or functional groups is the cause of poor growth on carbon-based substrates, we reckon that the major cause is the discrepancy between the hydrophilic nature of the metal oxide/hydroxide and the hydrophobic nature of carbon. To solve this incompatibility, we introduced ethanol into the precursor solution. The method to synthesize nickel copper hydroxide on carbon fiber paper employs only water and ethanol, in addition to nickel acetate and copper acetate. The results revealed good growth and tight adhesion of active materials on carbon fiber paper substrates. The specific capacitance and energy density per total weight of the active material plus substrate (carbon fiber paper, current collector) reached 770 F g(-1) and 33 Wh kg(-1) (1798 F g(-1) and 54 Wh kg(-1) per weight of the active materials), owing to the high loading of active material and the light weight of carbon fiber paper. These results signified the achievability of light, cheap and high-performance supercapacitors by an environmental-friendly approach.

A cheap and non-destructive approach to increase coverage/loading of hydrophilic hydroxide on hydrophobic carbon for lightweight and high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Zhang, Liuyang; Gong, Hao

2015-12-01

Carbon-based substrates offer unprecedented advantages in lightweight supercapacitors. However, it is still challenging to achieve high coverage or loading. Different from the traditional belief that a lack of defects or functional groups is the cause of poor growth on carbon-based substrates, we reckon that the major cause is the discrepancy between the hydrophilic nature of the metal oxide/hydroxide and the hydrophobic nature of carbon. To solve this incompatibility, we introduced ethanol into the precursor solution. The method to synthesize nickel copper hydroxide on carbon fiber paper employs only water and ethanol, in addition to nickel acetate and copper acetate. The results revealed good growth and tight adhesion of active materials on carbon fiber paper substrates. The specific capacitance and energy density per total weight of the active material plus substrate (carbon fiber paper, current collector) reached 770 F g-1 and 33 Wh kg-1 (1798 F g-1 and 54 Wh kg-1 per weight of the active materials), owing to the high loading of active material and the light weight of carbon fiber paper. These results signified the achievability of light, cheap and high-performance supercapacitors by an environmental-friendly approach.

A cheap and non-destructive approach to increase coverage/loading of hydrophilic hydroxide on hydrophobic carbon for lightweight and high-performance supercapacitors

PubMed Central

Zhang, Liuyang; Gong, Hao

2015-01-01

Carbon-based substrates offer unprecedented advantages in lightweight supercapacitors. However, it is still challenging to achieve high coverage or loading. Different from the traditional belief that a lack of defects or functional groups is the cause of poor growth on carbon-based substrates, we reckon that the major cause is the discrepancy between the hydrophilic nature of the metal oxide/hydroxide and the hydrophobic nature of carbon. To solve this incompatibility, we introduced ethanol into the precursor solution. The method to synthesize nickel copper hydroxide on carbon fiber paper employs only water and ethanol, in addition to nickel acetate and copper acetate. The results revealed good growth and tight adhesion of active materials on carbon fiber paper substrates. The specific capacitance and energy density per total weight of the active material plus substrate (carbon fiber paper, current collector) reached 770 F g−1 and 33 Wh kg−1 (1798 F g−1 and 54 Wh kg−1 per weight of the active materials), owing to the high loading of active material and the light weight of carbon fiber paper. These results signified the achievability of light, cheap and high-performance supercapacitors by an environmental-friendly approach. PMID:26643665

Variability in the primary emissions and secondary gas and particle formation from vehicles using bioethanol mixtures.

PubMed

Gramsch, E; Papapostolou, V; Reyes, F; Vásquez, Y; Castillo, M; Oyola, P; López, G; Cádiz, A; Ferguson, S; Wolfson, M; Lawrence, J; Koutrakis, P

2018-04-01

Bioethanol for use in vehicles is becoming a substantial part of global energy infrastructure because it is renewable and some emissions are reduced. Carbon monoxide (CO) emissions and total hydrocarbons (THC) are reduced, but there is still controversy regarding emissions of nitrogen oxides (NO x ), aldehydes, and ethanol; this may be a concern because all these compounds are precursors of ozone and secondary organic aerosol (SOA). The amount of emissions depends on the ethanol content, but it also may depend on the engine quality and ethanol origin. Thus, a photochemical chamber was used to study secondary gas and aerosol formation from two flex-fueled vehicles using different ethanol blends in gasoline. One vehicle and the fuel used were made in the United States, and the others were made in Brazil. Primary emissions of THC, CO, carbon dioxide (CO 2 ), and nonmethane hydrocarbons (NMHC) from both vehicles decreased as the amount of ethanol in gasoline increased. NO x emissions in the U.S. and Brazilian cars decreased with ethanol content. However, emissions of THC, CO, and NO x from the Brazilian car were markedly higher than those from the U.S. car, showing high variability between vehicle technologies. In the Brazilian car, formation of secondary nitrogen dioxide (NO 2 ) and ozone (O 3 ) was lower for higher ethanol content in the fuel. In the U.S. car, NO 2 and O 3 had a small increase. Secondary particle (particulate matter [PM]) formation in the chamber decreased for both vehicles as the fraction of ethanol in fuel increased, consistent with previous studies. Secondary to primary PM ratios for pure gasoline is 11, also consistent with previous studies. In addition, the time required to form secondary PM is longer for higher ethanol blends. These results indicate that using higher ethanol blends may have a positive impact on air quality. The use of bioethanol can significantly reduce petroleum use and greenhouse gas emissions worldwide. Given the extent of its use, it is important to understand its effect on urban pollution. There is a controversy on whether there is a reduction or increase in PM emission when using ethanol blends. Primary emissions of THC, CO, CO 2 , NO x , and NMHC for both cars decreased as the fraction of ethanol in gasoline increased. Using a photochemical chamber, the authors have found a decrease in the formation of secondary particles and the time required to form secondary PM is longer when using higher ethanol blends.

Nitrogen-fixing and cellulose-producing Gluconacetobacter kombuchae sp. nov., isolated from Kombucha tea.

PubMed

Dutta, Debasree; Gachhui, Ratan

2007-02-01

A few members of the family Acetobacteraceae are cellulose-producers, while only six members fix nitrogen. Bacterial strain RG3T, isolated from Kombucha tea, displays both of these characteristics. A high bootstrap value in the 16S rRNA gene sequence-based phylogenetic analysis supported the position of this strain within the genus Gluconacetobacter, with Gluconacetobacter hansenii LMG 1527T as its nearest neighbour (99.1 % sequence similarity). It could utilize ethanol, fructose, arabinose, glycerol, sorbitol and mannitol, but not galactose or xylose, as sole sources of carbon. Single amino acids such as L-alanine, L-cysteine and L-threonine served as carbon and nitrogen sources for growth of strain RG3T. Strain RG3T produced cellulose in both nitrogen-free broth and enriched medium. The ubiquinone present was Q-10 and the DNA base composition was 55.8 mol% G+C. It exhibited low values of 5.2-27.77 % DNA-DNA relatedness to the type strains of related gluconacetobacters, which placed it within a separate taxon, for which the name Gluconacetobacter kombuchae sp. nov. is proposed, with the type strain RG3T (=LMG 23726T=MTCC 6913T).

Production of polyhydroxyalkanoates from methanol by a new methylotrophic bacterium Methylobacterium sp. GW2.

PubMed

Yezza, A; Fournier, D; Halasz, A; Hawari, J

2006-11-01

A new bacterial strain, isolated from groundwater contaminated with explosives, was characterized as a pink-pigmented facultative methylotroph, affiliated to the genus Methylobacterium. The bacterial isolate designated as strain GW2 was found capable of producing the homopolymer poly-3-hydroxybutyrate (PHB) from various carbon sources such as methanol, ethanol, and succinate. Methanol acted as the best substrate for the production of PHB reaching 40 % w/w dry biomass. PHB accumulation was observed to be a growth-associated process, so that there was no need for two-step fermentation. Optimal growth occurred at 0.5 % (v/v) methanol concentration, and growth was strongly inhibited at alpha concentration above 2 % (v/v). Methylobacterium sp. strain GW2 was also able to accumulate the copolyester poly-3-hydroxybutyrate-poly-3-hydroxyvalerate (PHB/HV) when valeric acid was supplied as an auxiliary carbon source to methanol. After 66 h, a copolymer content of 30 % (w/w) was achieved with a PHB to PHV ratio of 1:2. Biopolymers produced by strain GW2 had an average molecular weight ranging from 229,350 to 233,050 Da for homopolymer PHB and from 362,430 to 411,300 Da for the copolymer PHB/HV.

An internal deletion in MTH1 enables growth on glucose of pyruvate-decarboxylase negative, non-fermentative Saccharomyces cerevisiae

PubMed Central

2012-01-01

Background Pyruvate-decarboxylase negative (Pdc-) strains of Saccharomyces cerevisiae combine the robustness and high glycolytic capacity of this yeast with the absence of alcoholic fermentation. This makes Pdc-S. cerevisiae an interesting platform for efficient conversion of glucose towards pyruvate-derived products without formation of ethanol as a by-product. However, Pdc- strains cannot grow on high glucose concentrations and require C2-compounds (ethanol or acetate) for growth under conditions with low glucose concentrations, which hitherto has limited application in industry. Results Genetic analysis of a Pdc- strain previously evolved to overcome these deficiencies revealed a 225bp in-frame internal deletion in MTH1, encoding a transcriptional regulator involved in glucose sensing. This internal deletion contains a phosphorylation site required for degradation, thereby hypothetically resulting in increased stability of the protein. Reverse engineering of this alternative MTH1 allele into a non-evolved Pdc- strain enabled growth on 20 g l-1 glucose and 0.3% (v/v) ethanol at a maximum specific growth rate (0.24 h-1) similar to that of the evolved Pdc- strain (0.23 h-1). Furthermore, the reverse engineered Pdc- strain grew on glucose as sole carbon source, albeit at a lower specific growth rate (0.10 h-1) than the evolved strain (0.20 h-1). The observation that overexpression of the wild-type MTH1 allele also restored growth of Pdc-S. cerevisiae on glucose is consistent with the hypothesis that the internal deletion results in decreased degradation of Mth1. Reduced degradation of Mth1 has been shown to result in deregulation of hexose transport. In Pdc- strains, reduced glucose uptake may prevent intracellular accumulation of pyruvate and/or redox problems, while release of glucose repression due to the MTH1 internal deletion may contribute to alleviation of the C2-compound auxotrophy. Conclusions In this study we have discovered and characterised a mutation in MTH1 enabling Pdc- strains to grow on glucose as the sole carbon source. This successful example of reverse engineering not only increases the understanding of the glucose tolerance of evolved Pdc-S. cerevisiae, but also allows introduction of this portable genetic element into various industrial yeast strains, thereby simplifying metabolic engineering strategies. PMID:22978798

Utilization of Cheese Whey Using Synergistic Immobilization of β-Galactosidase and Saccharomyces cerevisiae Cells in Dual Matrices.

PubMed

Kokkiligadda, Anusha; Beniwal, Arun; Saini, Priyanka; Vij, Shilpa

2016-08-01

Whey is a byproduct of the dairy industry, which has prospects of using as a source for production of various valuable compounds. The lactose present in whey is considered as an environmental pollutant and its utilization for enzyme and fuel production, may be effective for whey bioremediation. The dairy yeast Kluyveromyces marxianus have the ability to utilize lactose sharply as the major carbon source for the production of the enzyme. Five strains were tested for the production of the β-galactosidase using whey. The maximum β-galactosidase activity of 1.74 IU/mg dry weight was achieved in whey using K. marxianus MTCC 1389. The biocatalyst was further immobilized on chitosan macroparticles and exhibited excellent functional activity at 35 °C. Almost 89 % lactose hydrolysis was attained for concentrated whey (100 g/L) and retained 89 % catalytic activity after 15 cycles of reuse. Finally, β-galactosidase was immobilized on chitosan and Saccharomyces cerevisiae on calcium alginate, and both were used together for the production of ethanol from concentrated whey. Maximal ethanol titer of 28.9 g/L was achieved during fermentation at 35 °C. The conclusions generated by employing two different matrices will be beneficial for the future modeling using engineered S. cerevisiae in scale-up studies.

Ultrasound-assisted synthesis and processing of carbon materials

NASA Astrophysics Data System (ADS)

Fortunato, Maria E.

2011-12-01

Part I: Porous carbons are of interest in many applications because of their high surface areas and other physicochemical properties, and much effort has been directed towards developing new methods for controlling the porosity of carbons. Ultrasonic spray pyrolysis (USP) is an aerosol method suitable for large-scale, continuous synthesis of materials. Ultrasound is used to create aerosol droplets of a precursor solution which serve as micron-sized spherical reactors for materials synthesis. This work presents a precursor system for the template-free USP synthesis of porous carbons using low-cost precursors that do not evolve or require hazardous chemicals: sucrose was used as the carbon source, and sodium carbonate, sodium bicarbonate, or sodium nitrate was added as a decomposition catalyst and porogen. The USP carbons had macroporous interiors and microporous shells with surface areas as high as 800 m2/g and a narrow pore size distribution. It was determined that the interior porosity was a result of the gas evolution from salt decomposition and not from the presence of a salt template. Porous carbon is frequently used as a catalyst support because it provides high surface area and it is chemically and physically stable under many anoxic reaction conditions. Typically, the preparation of supported catalysts requires multiple steps for carbonization and metal impregnation. In this work, iron-impregnated porous carbon microspheres (Fe-C) were prepared by a one-step USP process by incorporating both the carbon and metal sources into the precursor solution. Carbonization, pore formation, metal impregnation, and metal activation occurred simultaneously to produce Fe-C materials with surface areas as high as 800 m2/g and up to 10 wt% Fe incorporated as nanoparticles < 20 nm in diameter. Fe-C was used as a catalyst to reduce aqueous hexavalent chromium, which demonstrated the accessibility of the iron nanoparticles despite the fact that they are likely encapsulated in the porous carbon support. Part II: The effects of high intensity ultrasound arise from acoustic cavitation: the formation, growth, and collapse of bubbles in a liquid. Bubble collapse produces intense localized heating (˜5000 K), high pressures (˜300 atm), and enormous heating and cooling rates (>109 K/sec). In solid-liquid slurries, surface erosion and particle fracture occur due to the shockwaves and microjets formed from asymmetric bubble collapse at extended surfaces. The chemical and physical effects of ultrasound have been studied as an adjunct to the traditional chemical pretreatment of lignocellulosic biomass for ethanol production. Lignocellulosic biomass consists of cellulose, hemicellulose, and lignin. The surface effects of ultrasound were used in this work to increase the accessibility of the cellulose, which can be converted to glucose and then fermented into ethanol. The lignocellulosic biomass used in this work was Miscanthus x giganteus (Mxg) which was grown at the University of Illinois at Urbana-Champaign. The chemical effects of NaOH pretreatment on Mxg were enhanced by ultrasound: greater delignification and a significant increase in the amount of pores >5 nm were observed. ˜ 70% of the theoretical glucose yield was obtained by enzymatic saccharification of the ultrasound-assisted NaOH-pretreated Mxg; this is comparable to the yields that can be obtained by traditional alkaline pretreatments, but it was achieved in a shorter time and at a lower temperature. Because the apparatus used for laboratory studies is not a likely device for scale-up, the economics of ultrasound with regards to energy balance are not yet resolved.

Alcohol-to-acid ratio and substrate concentration affect product structure in chain elongation reactions initiated by unacclimatized inoculum.

PubMed

Liu, Yuhao; Lü, Fan; Shao, Liming; He, Pinjing

2016-10-01

The objective of the study was to investigate whether the ratio of ethanol to acetate affects yield and product structure in chain elongation initiated by unacclimatized mixed cultures. The effect of varying the substrate concentration, while maintaining the same ratio of alcohol to acid, was also investigated. With a high substrate concentration, an alcohol to acid ratio >2:1 provided sufficient electron donor capacity for the chain elongation reaction. With an ethanol to acetate ratio of 3:1 (300mM total carbon), the highest n-caproate concentration (3033±98mg/L) was achieved during the stable phase of the reaction. A lower substrate concentration (150mM total carbon) gave a lower yield of products and led to reduced carbon transformation efficiency compared with other reaction conditions. The use of unacclimatized inoculum in chain elongation can produce significant amounts of odd-carbon-number carboxylates as a result of protein hydrolysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Waste to chemicals for a circular economy.

PubMed

Iaquaniello, Gaetano; Centi, Gabriele; Annarita Salladini, Annarita; Palo, Emma; Perathoner, Siglinda

2018-06-25

The implementation of a circular economy is a fundamental step to create a greater and more sustainable future for a better use of resources and energy. Wastes and in particular municipal solid waste represent an untapped source of carbon (and hydrogen) to produce a large range of chemicals from methane to alcohols (as methanol or ethanol) or urea. The waste to chemical (WtC) process and related economics are assessed in this concept article to show the validity of such solution both from an economic point of view and from an environmental perspective considering the sensible reduction in greenhouse gas emissions with respect to conventional production from fossil fuels. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bio-Fuel Production Assisted with High Temperature Steam Electrolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grant Hawkes; James O'Brien; Michael McKellar

2012-06-01

Two hybrid energy processes that enable production of synthetic liquid fuels that are compatible with the existing conventional liquid transportation fuels infrastructure are presented. Using biomass as a renewable carbon source, and supplemental hydrogen from high-temperature steam electrolysis (HTSE), these two hybrid energy processes have the potential to provide a significant alternative petroleum source that could reduce dependence on imported oil. The first process discusses a hydropyrolysis unit with hydrogen addition from HTSE. Non-food biomass is pyrolyzed and converted to pyrolysis oil. The pyrolysis oil is upgraded with hydrogen addition from HTSE. This addition of hydrogen deoxygenates the pyrolysis oilmore » and increases the pH to a tolerable level for transportation. The final product is synthetic crude that could then be transported to a refinery and input into the already used transportation fuel infrastructure. The second process discusses a process named Bio-Syntrolysis. The Bio-Syntrolysis process combines hydrogen from HTSE with CO from an oxygen-blown biomass gasifier that yields syngas to be used as a feedstock for synthesis of liquid synthetic crude. Conversion of syngas to liquid synthetic crude, using a biomass-based carbon source, expands the application of renewable energy beyond the grid to include transportation fuels. It can also contribute to grid stability associated with non-dispatchable power generation. The use of supplemental hydrogen from HTSE enables greater than 90% utilization of the biomass carbon content which is about 2.5 times higher than carbon utilization associated with traditional cellulosic ethanol production. If the electrical power source needed for HTSE is based on nuclear or renewable energy, the process is carbon neutral. INL has demonstrated improved biomass processing prior to gasification. Recyclable biomass in the form of crop residue or energy crops would serve as the feedstock for this process. A process model of syngas production using high temperature electrolysis and biomass gasification is presented. Process heat from the biomass gasifier is used to heat steam for the hydrogen production via the high temperature steam electrolysis process. Oxygen produced form the electrolysis process is used to control the oxidation rate in the oxygen-blown biomass gasifier.« less

Fe(III) and S0 reduction by Pelobacter carbinolicus

USGS Publications Warehouse

Lovley, D.R.; Phillips, E.J.P.; Lonergan, D.J.; Widma, P.K.

1995-01-01

There is a close phylogenetic relationship between Pelobacter species and members of the genera Desulfuromonas and Geobacter, and yet there has been a perplexing lack of physiological similarities. Pelobacter species have been considered to have a fermentative metabolism. In contrast, Desulfuromonas and Geobacter species have a respiratory metabolism with Fe(III) serving as the common terminal electron acceptor in all species. However, the ability of Pelobacter species to reduce Fe(III) had not been previously evaluated. When a culture of Pelobacter carbinolicus that had grown by fermentation of 2,3- butanediol was inoculated into the same medium supplemented with Fe(III), the Fe(III) was reduced. There was less accumulation of ethanol and more production of acetate in the presence of Fe(III). P. carbinolicus grew with ethanol as the sole electron donor and Fe(III) as the sole electron acceptor. Ethanol was metabolized to acetate. Growth was also possible on Fe(III) with the oxidation of propanol to propionate or butanol to butyrate if acetate was provided as a carbon source. P. carbinolicus appears capable of conserving energy to support growth from Fe(III) respiration as it also grew with H2 or formate as the electron donor and Fe(III) as the electron acceptor. Once adapted to Fe(III) reduction, P. carbinolicus could also grow on ethanol or H2 with S0 as the electron acceptor. P. carbinolicus did not contain detectable concentrations of the c-type cytochromes that previous studies have suggested are involved in electron transport to Fe(III) in other organisms that conserve energy to support growth from Fe(III) reduction. These results demonstrate that P. carbinolicus may survive in some sediments as an Fe(III) or S0 reducer rather than growing fermentatively on rare substrates or syntrophically as an ethanol-oxidizing acetogen. These studies also suggest that the ability to use Fe(III) as a terminal electron acceptor may be an important unifying feature of the Geobacter-Desulfuromonas- Pelobacter branch of the delta Proteobacteria.

EPA Biofuels Research: Effects of Inhaled Ethanol on Cortical Functions in the Offspring of Rats Exposed During Gestation.**

EPA Science Inventory

Due to the increased interest in ethanol blends as an alternative fuel source, there is a need to assess their possible health risks to sensitive populations. Specifically, ethanol is known to alter cortical functions such as attention, processing speed, movement, working memory,...

Ethanol at levels produced by Saccharomyces cerevisiae during wheat dough fermentation has a strong impact on dough properties.

PubMed

Jayaram, Vinay B; Rezaei, Mohammad N; Cuyvers, Sven; Verstrepen, Kevin J; Delcour, Jan A; Courtin, Christophe M

2014-09-24

Yeast's role in bread making is primarily the fermentative production of carbon dioxide to leaven the dough. Fermentation also impacts dough matrix rheology, thereby affecting the quality of the end product. Surprisingly, the role of ethanol, the other yeast primary metabolite, has been ill studied in this context. Therefore, this study aims to assess the potential impact of ethanol on yeastless dough extensibility and spread and gluten agglomeration at concentrations at which it is produced in fermenting dough, i.e., up to 60 mmol per 100 g of flour. Reduced dough extensibility and dough spread were observed upon incorporation of ethanol in the dough formula, and were more pronounced for a weak than for a strong flour. Uniaxial and biaxial extension tests showed up to 50% decrease in dough extensibility and a dough strength increase of up to 18% for 60 mmol of ethanol/100 g of flour. Ethanol enhanced gluten agglomeration of a weak flour. Sequential extraction of flour in increasing ethanol concentrations showed that better gluten-solvent interaction is a possible explanation for the changed dough behavior.

Changes in carbon footprint when integrating production of filamentous fungi in 1st generation ethanol plants.

PubMed

Brancoli, Pedro; Ferreira, Jorge A; Bolton, Kim; Taherzadeh, Mohammad J

2018-02-01

Integrating the cultivation of edible filamentous fungi in the thin stillage from ethanol production is presently being considered. This integration can increase the ethanol yield while simultaneously producing a new value-added protein-rich biomass that can be used for animal feed. This study uses life cycle assessment to determine the change in greenhouse gas (GHG) emissions when integrating the cultivation of filamentous fungi in ethanol production. The result shows that the integration performs better than the current scenario when the fungal biomass is used as cattle feed for system expansion and when energy allocation is used. It performs worse if the biomass is used as fish feed. Hence, integrating the cultivation of filamentous fungi in 1st generation ethanol plants combined with proper use of the fungi can lead to a reduction of GHG emissions which, considering the number of existing ethanol plants, can have a significant global impact. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enhancing ethanol production from thermophilic and mesophilic solid digestate using ozone combined with aqueous ammonia pretreatment.

PubMed

Wang, Dianlong; Xi, Jiang; Ai, Ping; Yu, Liang; Zhai, Hong; Yan, Shuiping; Zhang, Yanlin

2016-05-01

Pretreatment with ozone combined with aqueous ammonia was used to recover residual organic carbon from recalcitrant solid digestate for ethanol production after anaerobic digestion (AD) of rice straw. Methane yield of AD at mesophilic and thermophilic conditions, and ethanol production of solid digestate were investigated. The results showed that the methane yield at thermophilic temperature was 72.2% higher than that at mesophilic temperature under the same conditions of 24days and 17% solid concentration. And also the ethanol production efficiency of solid digestate after thermophilic process was 24.3% higher than that of solid digestate after mesophilic process. In this study, the optimal conditions for integrated methane and ethanol processes were determined as 55°C, 17% solid concentration and 24days. 58.6% of glucose conversion, 142.8g/kg of methane yield and 65.2g/kg of ethanol yield were achieved, and the highest net energy balance was calculated as 6416kJ/kg. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simultaneous hydrolysis and fermentation of unprocessed food waste into ethanol using thermophilic anaerobic bacteria.

PubMed

Dhiman, Saurabh Sudha; David, Aditi; Shrestha, Namita; Johnson, Glenn R; Benjamin, Kenneth M; Gadhamshetty, Venkataramana; Sani, Rajesh K

2017-11-01

The one-pot CRUDE (Conversion of Raw and Untreated Disposal into Ethanol) process was developed for simultaneous hydrolysis and fermentation of unprocessed food waste into ethanol using thermophilic (growing at 65°C) anaerobic bacteria. Unlike existing waste to energy technologies, the CRUDE process obviates the need for any pre-treatment or enzyme addition. A High-Temperature-High-Pressure (HTHP) distillation technique was also applied that facilitated efficient use of fermentation medium, inoculum recycling, and in-situ ethanol collection. For material balancing of the process, each characterized component was represented in terms of C-mol. Recovery of 94% carbon at the end confirmed the operational efficiency of CRUDE process. The overall energy retaining efficiency calculated from sugars to ethanol was 1262.7kJdryweightkg -1 of volatile solids using HTHP. These results suggest that the CRUDE process can be a starting point for the development of a commercial ethanol production process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Energy and exergy analysis of an ethanol reforming process for solid oxide fuel cell applications.

PubMed

Tippawan, Phanicha; Arpornwichanop, Amornchai

2014-04-01

The fuel processor in which hydrogen is produced from fuels is an important unit in a fuel cell system. The aim of this study is to apply a thermodynamic concept to identify a suitable reforming process for an ethanol-fueled solid oxide fuel cell (SOFC). Three different reforming technologies, i.e., steam reforming, partial oxidation and autothermal reforming, are considered. The first and second laws of thermodynamics are employed to determine an energy demand and to describe how efficiently the energy is supplied to the reforming process. Effect of key operating parameters on the distribution of reforming products, such as H2, CO, CO2 and CH4, and the possibility of carbon formation in different ethanol reformings are examined as a function of steam-to-ethanol ratio, oxygen-to-ethanol ratio and temperatures at atmospheric pressure. Energy and exergy analysis are performed to identify the best ethanol reforming process for SOFC applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

Separation, hydrolysis and fermentation of pyrolytic sugars to produce ethanol and lipids.

PubMed

Lian, Jieni; Chen, Shulin; Zhou, Shuai; Wang, Zhouhong; O'Fallon, James; Li, Chun-Zhu; Garcia-Perez, Manuel

2010-12-01

This paper describes a new scheme to convert anhydrosugars found in pyrolysis oils into ethanol and lipids. Pyrolytic sugars were separated from phenols by solvent extraction and were hydrolyzed into glucose using sulfuric acid as a catalyst. Toxicological studies showed that phenols and acids were the main species inhibiting growth of the yeast Saccharomyces cerevisiae. The sulfuric acids, and carboxylic acids from the bio-oils, were neutralized with Ba(OH)(2). The phase rich in sugar was further detoxified with activated carbon. The resulting aqueous phase rich in glucose was fermented with three different yeasts: S. cerevisiae to produce ethanol, and Cryptococcus curvatus and Rhodotorula glutinis to produce lipids. Yields as high as 0.473 g ethanol/g glucose and 0.167 g lipids/g sugar (0.266 g ethanol equivalent/g sugar), were obtained. These results confirm that pyrolytic sugar fermentation to produce ethanol is more efficient than for lipid production. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

A comparative study of methanol as a supplementary carbon source for enhancing denitrification in primary and secondary anoxic zones.

PubMed

Ginige, Maneesha P; Bowyer, Jocelyn C; Foley, Leah; Keller, Jürg; Yuan, Zhiguo

2009-04-01

A comparative study on the use of methanol as a supplementary carbon source to enhance denitrification in primary and secondary anoxic zones is reported. Three lab-scale sequencing batch reactors (SBR) were operated to achieve nitrogen and carbon removal from domestic wastewater. Methanol was added to the primary anoxic period of the first SBR, and to the secondary anoxic period of the second SBR. No methanol was added to the third SBR, which served as a control. The extent of improvement on the denitrification performance was found to be dependent on the reactor configuration. Addition to the secondary anoxic period is more effective when very low effluent nitrate levels are to be achieved and hence requires a relatively large amount of methanol. Adding a small amount of methanol to the secondary anoxic period may cause nitrite accumulation, which does not improve overall nitrogen removal. In the latter case, methanol should be added to the primary anoxic period. The addition of methanol can also improve biological phosphorus removal by creating anaerobic conditions and increasing the availability of organic carbon in wastewater for polyphosphate accumulating organisms. This potentially provides a cost-effective approach to phosphorus removal from wastewater with a low carbon content. New fluorescence in situ hybridisation (FISH) probes targeting methanol-utilising denitrifiers were designed using stable isotope probing. Microbial structure analysis of the sludges using the new and existing FISH probes clearly showed that the addition of methanol stimulated the growth of specific methanol-utilizing denitrifiers, which improved the capability of sludge to use methanol and ethanol for denitrification, but reduced its capability to use wastewater COD for denitrification. Unlike acetate, long-term application of methanol has no negative impact on the settling properties of the sludge.

Longitudinal Hierarchy Co3O4 Mesocrystals with High-dense Exposure Facets and Anisotropic Interfaces for Direct-Ethanol Fuel Cells.

PubMed

Hassen, Diab; El-Safty, Sherif A; Tsuchiya, Koichi; Chatterjee, Abhijit; Elmarakbi, Ahmed; Shenashen, Mohamed A; Sakai, Masaru

2016-04-14

Novel electrodes are needed for direct ethanol fuel cells with improved quality. Hierarchical engineering can produce catalysts composed of mesocrystals with many exposed active planes and multi-diffused voids. Here we report a simple, one-pot, hydrothermal method for fabricating Co3O4/carbon/substrate electrodes that provides control over the catalyst mesocrystal morphology (i.e., corn tubercle pellets or banana clusters oriented along nanotube domains, or layered lamina or multiple cantilevered sheets). These morphologies afforded catalysts with a high density of exposed active facets, a diverse range of mesopores in the cage interior, a window architecture, and vertical alignment to the substrate, which improved efficiency in an ethanol electrooxidation reaction compared with a conventional platinum/carbon electrode. On the atomic scale, the longitudinally aligned architecture of the Co3O4 mesocrystals resulted in exposed low- and high-index single and interface surfaces that had improved electron transport and diffusion compared with currently used electrodes.

Longitudinal Hierarchy Co3O4 Mesocrystals with High-dense Exposure Facets and Anisotropic Interfaces for Direct-Ethanol Fuel Cells

NASA Astrophysics Data System (ADS)

Hassen, Diab; El-Safty, Sherif A.; Tsuchiya, Koichi; Chatterjee, Abhijit; Elmarakbi, Ahmed; Shenashen, Mohamed. A.; Sakai, Masaru

2016-04-01

Novel electrodes are needed for direct ethanol fuel cells with improved quality. Hierarchical engineering can produce catalysts composed of mesocrystals with many exposed active planes and multi-diffused voids. Here we report a simple, one-pot, hydrothermal method for fabricating Co3O4/carbon/substrate electrodes that provides control over the catalyst mesocrystal morphology (i.e., corn tubercle pellets or banana clusters oriented along nanotube domains, or layered lamina or multiple cantilevered sheets). These morphologies afforded catalysts with a high density of exposed active facets, a diverse range of mesopores in the cage interior, a window architecture, and vertical alignment to the substrate, which improved efficiency in an ethanol electrooxidation reaction compared with a conventional platinum/carbon electrode. On the atomic scale, the longitudinally aligned architecture of the Co3O4 mesocrystals resulted in exposed low- and high-index single and interface surfaces that had improved electron transport and diffusion compared with currently used electrodes.

Biofuel components change the ecology of bacterial volatile petroleum hydrocarbon degradation in aerobic sandy soil.

PubMed

Elazhari-Ali, Abdulmagid; Singh, Arvind K; Davenport, Russell J; Head, Ian M; Werner, David

2013-02-01

We tested the hypothesis that the biodegradation of volatile petroleum hydrocarbons (VPHs) in aerobic sandy soil is affected by the blending with 10 percent ethanol (E10) or 20 percent biodiesel (B20). When inorganic nutrients were scarce, competition between biofuel and VPH degraders temporarily slowed monoaromatic hydrocarbon degradation. Ethanol had a bigger impact than biodiesel, reflecting the relative ease of ethanol compared to methyl ester biodegradation. Denaturing gradient gel electrophoresis (DGGE) of bacterial 16S rRNA genes revealed that each fuel mixture selected for a distinct bacterial community, each dominated by Pseudomonas spp. Despite lasting impacts on soil bacterial ecology, the overall effects on VHP biodegradation were minor, and average biomass yields were comparable between fuel types, ranging from 0.40 ± 0.16 to 0.51 ± 0.22 g of biomass carbon per gram of fuel carbon degraded. Inorganic nutrient availability had a greater impact on petroleum hydrocarbon biodegradation than fuel composition. Copyright © 2012 Elsevier Ltd. All rights reserved.

Longitudinal Hierarchy Co3O4 Mesocrystals with High-dense Exposure Facets and Anisotropic Interfaces for Direct-Ethanol Fuel Cells

PubMed Central

Hassen, Diab; El-Safty, Sherif A.; Tsuchiya, Koichi; Chatterjee, Abhijit; Elmarakbi, Ahmed; Shenashen, Mohamed. A.; Sakai, Masaru

2016-01-01

Novel electrodes are needed for direct ethanol fuel cells with improved quality. Hierarchical engineering can produce catalysts composed of mesocrystals with many exposed active planes and multi-diffused voids. Here we report a simple, one-pot, hydrothermal method for fabricating Co3O4/carbon/substrate electrodes that provides control over the catalyst mesocrystal morphology (i.e., corn tubercle pellets or banana clusters oriented along nanotube domains, or layered lamina or multiple cantilevered sheets). These morphologies afforded catalysts with a high density of exposed active facets, a diverse range of mesopores in the cage interior, a window architecture, and vertical alignment to the substrate, which improved efficiency in an ethanol electrooxidation reaction compared with a conventional platinum/carbon electrode. On the atomic scale, the longitudinally aligned architecture of the Co3O4 mesocrystals resulted in exposed low- and high-index single and interface surfaces that had improved electron transport and diffusion compared with currently used electrodes. PMID:27075551

Moderate (2%, v/v) Ethanol Feeding Alters Hepatic Wound Healing after Acute Carbon Tetrachloride Exposure in Mice

PubMed Central

Deshpande, Krutika T.; Liu, Shinlan; McCracken, Jennifer M.; Jiang, Lu; Gaw, Ta Ehpaw; Kaydo, Lindsey N.; Richard, Zachary C.; O’Neil, Maura F.; Pritchard, Michele T.

2016-01-01

Wound healing consists of three overlapping phases: inflammation, proliferation, and matrix synthesis and remodeling. Prolonged alcohol abuse can cause liver fibrosis due to deregulated matrix remodeling. Previous studies demonstrated that moderate ethanol feeding enhances liver fibrogenic markers and frank fibrosis independent of differences in CCl4-induced liver injury. Our objective was to determine whether or not other phases of the hepatic wound healing response were affected by moderate ethanol after CCl4 exposure. Mice were fed moderate ethanol (2% v/v) for two days and then were exposed to CCl4 and euthanized 24–96 h later. Liver injury was not different between pair- and ethanol-fed mice; however, removal of necrotic tissue was delayed after CCl4-induced liver injury in ethanol-fed mice. Inflammation, measured by TNFα mRNA and protein and hepatic Ly6c transcript accumulation, was reduced and associated with enhanced hepatocyte apoptosis after ethanol feeding. Hepatocytes entered the cell cycle equivalently in pair- and ethanol-fed mice after CCl4 exposure, but hepatocyte proliferation was prolonged in livers from ethanol-fed mice. CCl4-induced hepatic stellate cell activation was increased and matrix remodeling was prolonged in ethanol-fed mice compared to controls. Taken together, moderate ethanol affected each phase of the wound healing response to CCl4. These data highlight previously unknown effects of moderate ethanol exposure on hepatic wound healing after acute hepatotoxicant exposure. PMID:26751492

Effects of Mid-Level Ethanol Blends on Conventional Vehicle Emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knoll, K.; West, B.; Huff, S.

2010-06-01

Tests were conducted in 2008 on 16 late-model conventional vehicles (1999-2007) to determine short-term effects of mid-level ethanol blends on performance and emissions. Vehicle odometer readings ranged from 10,000 to 100,000 miles, and all vehicles conformed to federal emissions requirements for their federal certification level. The LA92 drive cycle, also known as the Unified Cycle, was used for testing because it more accurately represents real-world acceleration rates and speeds than the Federal Test Procedure. Test fuels were splash-blends of up to 20 volume percent ethanol with federal certification gasoline. Both regulated and unregulated air-toxic emissions were measured. For the 16-vehiclemore » fleet, increasing ethanol content resulted in reductions in average composite emissions of both nonmethane hydrocarbons and carbon monoxide and increases in average emissions of ethanol and aldehydes.« less

New, efficient and viable system for ethanol fuel utilization on combined electric/internal combustion engine vehicles

NASA Astrophysics Data System (ADS)

Sato, André G.; Silva, Gabriel C. D.; Paganin, Valdecir A.; Biancolli, Ana L. G.; Ticianelli, Edson A.

2015-10-01

Although ethanol can be directly employed as fuel on polymer-electrolyte fuel cells (PEMFC), its low oxidation kinetics in the anode and the crossover to the cathode lead to a substantial reduction of energy conversion efficiency. However, when fuel cell driven vehicles are considered, the system may include an on board steam reformer for converting ethanol into hydrogen, but the hydrogen produced contains carbon monoxide, which limits applications in PEMFCs. Here, we present a system consisting of an ethanol dehydrogenation catalytic reactor for producing hydrogen, which is supplied to a PEMFC to generate electricity for electric motors. A liquid by-product effluent from the reactor can be used as fuel for an integrated internal combustion engine, or catalytically recycled to extract more hydrogen molecules. Power densities comparable to those of a PEMFC operating with pure hydrogen are attained by using the hydrogen rich stream produced by the ethanol dehydrogenation reactor.

L-Lactic acid production from glucose and xylose with engineered strains of Saccharomyces cerevisiae: aeration and carbon source influence yields and productivities.

PubMed

Novy, Vera; Brunner, Bernd; Nidetzky, Bernd

2018-04-11

Saccharomyces cerevisiae, engineered for L-lactic acid production from glucose and xylose, is a promising production host for lignocellulose-to-lactic acid processes. However, the two principal engineering strategies-pyruvate-to-lactic acid conversion with and without disruption of the competing pyruvate-to-ethanol pathway-have not yet resulted in strains that combine high lactic acid yields (Y LA ) and productivities (Q LA ) on both sugar substrates. Limitations seemingly arise from a dependency on the carbon source and the aeration conditions, but the underlying effects are poorly understood. We have recently presented two xylose-to-lactic acid converting strains, IBB14LA1 and IBB14LA1_5, which have the L-lactic acid dehydrogenase from Plasmodium falciparum (pfLDH) integrated at the pdc1 (pyruvate decarboxylase) locus. IBB14LA1_5 additionally has its pdc5 gene knocked out. In this study, the influence of carbon source and oxygen on Y LA and Q LA in IBB14LA1 and IBB14LA1_5 was investigated. In anaerobic fermentation IBB14LA1 showed a higher Y LA on xylose (0.27 g g Xyl -1 ) than on glucose (0.18 g g Glc -1 ). The ethanol yields (Y EtOH , 0.15 g g Xyl -1 and 0.32 g g Glc -1 ) followed an opposite trend. In IBB14LA1_5, the effect of the carbon source on Y LA was less pronounced (~ 0.80 g g Xyl -1 , and 0.67 g g Glc -1 ). Supply of oxygen accelerated glucose conversions significantly in IBB14LA1 (Q LA from 0.38 to 0.81 g L -1  h -1 ) and IBB14LA1_5 (Q LA from 0.05 to 1.77 g L -1  h -1 ) at constant Y LA (IBB14LA1 ~ 0.18 g g Glc -1 ; IBB14LA1_5 ~ 0.68 g g Glc -1 ). In aerobic xylose conversions, however, lactic acid production ceased completely in IBB14LA1 and decreased drastically in IBB14LA1_5 (Y LA aerobic ≤ 0.25 g g Xyl -1 and anaerobic ~ 0.80 g g Xyl -1 ) at similar Q LA (~ 0.04 g L -1  h -1 ). Switching from aerobic to microaerophilic conditions (pO 2  ~ 2%) prevented lactic acid metabolization, observed for fully aerobic conditions, and increased Q LA and Y LA up to 0.11 g L -1  h -1 and 0.38 g g Xyl -1 , respectively. The pfLDH and PDC activities in IBB14LA1 were measured and shown to change drastically dependent on carbon source and oxygen. Evidence from conversion time courses together with results of activity measurements for pfLDH and PDC show that in IBB14LA1 the distribution of fluxes at the pyruvate branching point is carbon source and oxygen dependent. Comparison of the performance of strain IBB14LA1 and IBB14LA1_5 in conversions under different aeration conditions (aerobic, anaerobic, and microaerophilic) further suggest that xylose, unlike glucose, does not repress the respiratory response in both strains. This study proposes new genetic engineering targets for rendering genetically engineering S. cerevisiae better suited for lactic acid biorefineries.

Direct conversion of plant biomass to ethanol by engineered Caldicellulosiruptor bescii

PubMed Central

Chung, Daehwan; Cha, Minseok; Guss, Adam M.; Westpheling, Janet

2014-01-01

Ethanol is the most widely used renewable transportation biofuel in the United States, with the production of 13.3 billion gallons in 2012 [John UM (2013) Contribution of the Ethanol Industry to the Economy of the United States]. Despite considerable effort to produce fuels from lignocellulosic biomass, chemical pretreatment and the addition of saccharolytic enzymes before microbial bioconversion remain economic barriers to industrial deployment [Lynd LR, et al. (2008) Nat Biotechnol 26(2):169–172]. We began with the thermophilic, anaerobic, cellulolytic bacterium Caldicellulosiruptor bescii, which efficiently uses unpretreated biomass, and engineered it to produce ethanol. Here we report the direct conversion of switchgrass, a nonfood, renewable feedstock, to ethanol without conventional pretreatment of the biomass. This process was accomplished by deletion of lactate dehydrogenase and heterologous expression of a Clostridium thermocellum bifunctional acetaldehyde/alcohol dehydrogenase. Whereas wild-type C. bescii lacks the ability to make ethanol, 70% of the fermentation products in the engineered strain were ethanol [12.8 mM ethanol directly from 2% (wt/vol) switchgrass, a real-world substrate] with decreased production of acetate by 38% compared with wild-type. Direct conversion of biomass to ethanol represents a new paradigm for consolidated bioprocessing, offering the potential for carbon neutral, cost-effective, sustainable fuel production. PMID:24889625

Direct conversion of plant biomass to ethanol by engineered Caldicellulosiruptor bescii.

PubMed

Chung, Daehwan; Cha, Minseok; Guss, Adam M; Westpheling, Janet

2014-06-17

Ethanol is the most widely used renewable transportation biofuel in the United States, with the production of 13.3 billion gallons in 2012 [John UM (2013) Contribution of the Ethanol Industry to the Economy of the United States]. Despite considerable effort to produce fuels from lignocellulosic biomass, chemical pretreatment and the addition of saccharolytic enzymes before microbial bioconversion remain economic barriers to industrial deployment [Lynd LR, et al. (2008) Nat Biotechnol 26(2):169-172]. We began with the thermophilic, anaerobic, cellulolytic bacterium Caldicellulosiruptor bescii, which efficiently uses unpretreated biomass, and engineered it to produce ethanol. Here we report the direct conversion of switchgrass, a nonfood, renewable feedstock, to ethanol without conventional pretreatment of the biomass. This process was accomplished by deletion of lactate dehydrogenase and heterologous expression of a Clostridium thermocellum bifunctional acetaldehyde/alcohol dehydrogenase. Whereas wild-type C. bescii lacks the ability to make ethanol, 70% of the fermentation products in the engineered strain were ethanol [12.8 mM ethanol directly from 2% (wt/vol) switchgrass, a real-world substrate] with decreased production of acetate by 38% compared with wild-type. Direct conversion of biomass to ethanol represents a new paradigm for consolidated bioprocessing, offering the potential for carbon neutral, cost-effective, sustainable fuel production.

Radiochemical synthesis of a carbon-supported Pt-SnO2 bicomponent nanostructure exhibiting enhanced catalysis of ethanol oxidation

NASA Astrophysics Data System (ADS)

Okazaki, Tomohisa; Seino, Satoshi; Nakagawa, Takashi; Kugai, Junichiro; Ohkubo, Yuji; Akita, Tomoki; Nitani, Hiroaki; Yamamoto, Takao A.

2015-03-01

Carbon-supported Pt-SnO2 electrocatalysts with various Sn/Pt molar ratios were prepared by an electron beam irradiation method. These catalysts were composed of metallic Pt particles approximately 5 nm in diameter together with low crystalline SnO2. The contact between the Pt and SnO2 in these materials varied with the amount of dissolved oxygen in the precursor solutions and it was determined that intimate contact between the Pt and SnO2 significantly enhanced the catalytic activity of these materials during the ethanol oxidation reaction. The mechanism by which the contact varies is discussed based on the radiochemical reduction process.

Structure and Optical Properties of Carbon Nanoparticles Generated by Laser Treatment of Graphite in Liquids.

PubMed

Tarasenka, Natalie; Stupak, Aleksandr; Tarasenko, Nikolai; Chakrabarti, Supriya; Mariotti, Davide

2017-05-05

In this paper, we report the one-step synthesis of luminescent carbon nanoparticles (NPs) via laser irradiation of a graphite target in a solvent [H 2 O, ethanol, or a 0.008 m aqueous diethylenetriaminepentaacetic acid (DTPA) solution]. This is a simple approach for the fabrication of carbon dots with tunable photoluminescence (PL) that differs from other preparation methods, as no post-passivation step is required. The unfocused beam of the second harmonic (wavelength 532 nm) of the Nd:YAG laser was used in our experiments. The sizes of the prepared NPs were mainly distributed in the range of 1-8 nm with an average value of 3 nm. Carbon NPs of different inner structure were prepared: hexagonal diamond phase in aqueous DTPA solution, orthorhombic carbon phase in ethanol, and amorphous carbon in water. The synthesized carbon NPs have strong luminescence in the visible region, which makes them attractive for numerous biological applications. The photoluminescence of the synthesized NPs was investigated at different excitation wavelengths, from 260 to 450 nm. The highest intensities of the emission bands were detected for an excitation wavelength of 400 nm. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analytical model for BTEX natural attenuation in the presence of fuel ethanol and its anaerobic metabolite acetate.

PubMed

da Silva, Marcio L B; Gomez, Diego E; Alvarez, Pedro J J

2013-03-01

Flow-through column studies were conducted to mimic the natural attenuation of ethanol and BTEX mixtures, and to consider potential inhibitory effects of ethanol and its anaerobic metabolite acetate on BTEX biodegradation. Results were analyzed using a one-dimensional analytical model that was developed using consecutive reaction differential equations based on first-order kinetics. Decrease in pH due to acetogenesis was also modeled, using charge balance equations under CaCO(3) dissolution conditions. Delay in BTEX removal was observed and simulated in the presence of ethanol and acetate. Acetate was the major volatile fatty acid intermediate produced during anaerobic ethanol biodegradation (accounting for about 58% of the volatile fatty acid mass) as suggested by the model data fit. Acetate accumulation (up to 1.1 g/L) near the source zone contributed to a pH decrease by almost one unit. The anaerobic degradation of ethanol (2 g/L influent concentration) at the source zone produced methane at concentrations exceeding its solubility (~/=26mg/L). Overall, this simple analytical model adequately described ethanol degradation, acetate accumulation and methane production patterns, suggesting that it could be used as a screening tool to simulate lag times in BTEX biodegradation, changes in groundwater pH and methane generation following ethanol-blended fuel releases. Copyright © 2012 Elsevier B.V. All rights reserved.

Aerobic and anaerobic glucose metabolism of Phytomonas sp. isolated from Euphorbia characias.

PubMed

Chaumont, F; Schanck, A N; Blum, J J; Opperdoes, F R

1994-10-01

Metabolic studies on Phytomonas sp. isolated from the lactiferous tubes of the latex-bearing spurge Euphorbia characias indicate that glucose is the preferred energy and carbon substrate during logarithmic growth. In stationary phase cells glucose consumption was dramatically reduced. Glucose consumption and end-product formation were measured on logarithmically growing cells, both under aerobic (air and 95% O2/5% CO2) and anaerobic (95% N2/5% CO2 and 100% N2) conditions. The rate of glucose consumption slightly increased under anaerobic conditions indicating that Phytomonas lacks a 'reverse Pasteur' effect contrary to the situation encountered in Leishmania major. Major end-products of glucose catabolism under aerobic conditions, detected by enzymatic and NMR measurements, were acetate, ethanol and carbon dioxide and under anaerobic conditions ethanol, glycerol and carbon dioxide. Smaller amounts of pyruvate, succinate, L-malate, L-lactate, phosphoenolpyruvate, alanine and aspartate were also detected.

In vitro fermentation of prebiotics by Lactobacillus plantarum CFR 2194: selectivity, viability and effect of metabolites on β-glucuronidase activity.

PubMed

Arenahalli Ningegowda, Madhu; Siddalingaiya Gurudutt, Prapulla

2012-03-01

Prebiotic Fructooligosaccharides (FOS) escape metabolism in upper GI tract undergo microbial metabolism in colon and thereby influence the nature, type and number of intestinal microbiota to improve host's health. The present study focuses on the ability of Lactobacillus plantarum CFR 2194 to utilize FOS as a selective carbon and energy source. The effect of fermentative metabolites of L. plantarum on the β-glucuronidase was also investigated. A total of 16 strains of lactobacilli were assessed for their ability to ferment oligosaccharides. L. plantarum CFR 2194, an isolate from kanjika was found to utilize FOS effectively. Lactic acid was the main metabolic end product, followed by acetic acid, butyric acid, formic acid and ethanol. The inhibitory effects of these metabolites have been confirmed through the reduction of β-glucuronidase activity. L. plantarum when co-cultured with β-glucuronidase producing E. coli, in a basal media containing FOS as an energy source, could inhibit the growth of the pathogen during the course of fermentation. The results showed that L. plantarum CFR 2194 has the ability to utilize the prebiotic FOS as a selective carbon and energy source. The organism could inhibit the growth of the pathogen which produces β-glucuronidase and lowered its activity by the metabolites of FOS which indicates the probable use of L. plantarum through dietary intervention in combating colon carcinogenesis.

High-throughput detection of ethanol-producing cyanobacteria in a microdroplet platform.

PubMed

Abalde-Cela, Sara; Gould, Anna; Liu, Xin; Kazamia, Elena; Smith, Alison G; Abell, Chris

2015-05-06

Ethanol production by microorganisms is an important renewable energy source. Most processes involve fermentation of sugars from plant feedstock, but there is increasing interest in direct ethanol production by photosynthetic organisms. To facilitate this, a high-throughput screening technique for the detection of ethanol is required. Here, a method for the quantitative detection of ethanol in a microdroplet-based platform is described that can be used for screening cyanobacterial strains to identify those with the highest ethanol productivity levels. The detection of ethanol by enzymatic assay was optimized both in bulk and in microdroplets. In parallel, the encapsulation of engineered ethanol-producing cyanobacteria in microdroplets and their growth dynamics in microdroplet reservoirs were demonstrated. The combination of modular microdroplet operations including droplet generation for cyanobacteria encapsulation, droplet re-injection and pico-injection, and laser-induced fluorescence, were used to create this new platform to screen genetically engineered strains of cyanobacteria with different levels of ethanol production.

Molecular and physiological aspects of alcohol dehydrogenases in the ethanol metabolism of Saccharomyces cerevisiae.

PubMed

de Smidt, Olga; du Preez, James C; Albertyn, Jacobus

2012-02-01

The physiological role and possible functional substitution of each of the five alcohol dehydrogenase (Adh) isozymes in Saccharomyces cerevisiae were investigated in five quadruple deletion mutants designated strains Q1-Q5, with the number indicating the sole intact ADH gene. Their growth in aerobic batch cultures was characterised in terms of kinetic and stoichiometric parameters. Cultivation with glucose or ethanol as carbon substrate revealed that Adh1 was the only alcohol dehydrogenase capable of efficiently catalysing the reduction of acetaldehyde to ethanol. The oxidation of produced or added ethanol could also be attributed to Adh1. Growth of strains lacking the ADH1 gene resulted in the production of glycerol as a major fermentation product, concomitant with the production of a significant amount of acetaldehyde. Strains Q2 and Q3, expressing only ADH2 or ADH3, respectively, produced ethanol from glucose, albeit less than strain Q1, and were also able to oxidise added ethanol. Strains Q4 and Q5 grew poorly on glucose and produced ethanol, but were neither able to utilise the produced ethanol nor grow on added ethanol. Transcription profiles of the ADH4 and ADH5 genes suggested that participation of these gene products in ethanol production from glucose was unlikely. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Silver sub-nanoclusters electrocatalyze ethanol oxidation and provide protection against ethanol toxicity in cultured mammalian cells.

PubMed

Selva, Javier; Martínez, Susana E; Buceta, David; Rodríguez-Vázquez, María J; Blanco, M Carmen; López-Quintela, M Arturo; Egea, Gustavo

2010-05-26

Silver atomic quantum clusters (AgAQCs), with two or three silver atoms, show electrocatalytic activities that are not found in nanoparticles or in bulk silver. AgAQCs supported on glassy carbon electrodes oxidize ethanol and other alcohols in macroscopic electrochemical cells in acidic and basic media. This electrocatalysis occurs at very low potentials (from approximately +200 mV vs RHE), at physiological pH, and at ethanol concentrations that are found in alcoholic patients. When mammalian cells are co-exposed to ethanol and AgAQCs, alcohol-induced alterations such as rounded cell morphology, disorganization of the actin cytoskeleton, and activation of caspase-3 are all prevented. This cytoprotective effect of AgAQCs is also observed in primary cultures of newborn rat astrocytes exposed to ethanol, which is a cellular model of fetal alcohol syndrome. AgAQCs oxidize ethanol from the culture medium only when ethanol and AgAQCs are added to cells simultaneously, which suggests that cytoprotection by AgAQCs is provided by the ethanol electro-oxidation mediated by the combined action of AgAQCs and cells. Overall, these findings not only show that AgAQCs are efficient electrocatalysts at physiological pH and prevent ethanol toxicity in cultured mammalian cells, but also suggest that AgAQCs could be used to modify redox reactions and in this way promote or inhibit biological reactions.

Ethanol production from woody biomass: Silvicultural opportunities for suppressed western conifers

Treesearch

Andrew Youngblood; Junyong Zhu; C. Tim Scott

2010-01-01

The 2007 Energy Security and Independence Act (ESIA) requires 16 billion gallons of ethanol to be produced from lignocellulose biomass by 2022 in the United States. Forests can be a key source of renewable lignocellulose for ethanol production if cost and conversion efficiency barriers can be overcome. We explored opportunities for using woody biomass from thinning...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Zongyuan; Duchon, Tomas; Wang, Huanru

Ambient-Pressure X-ray Photoelectron Spectroscopy (AP-XPS) and Infrared Reflection Absorption Spectroscopy (AP-IRRAS) have been used to elucidate the active sites and mechanistic steps associated with the ethanol steam reforming reaction (ESR) over Ni–CeO 2(111) model catalysts. Our results reveal that surface layers of the ceria substrate are both highly reduced and hydroxylated under reaction conditions while the small supported Ni nanoparticles are present as Ni 0/NixC. A multifunctional, synergistic role is highlighted in which Ni, CeO x and the interface provide an ensemble effect in the active chemistry that leads to H 2. Ni 0 is the active phase leading tomore » both C–C and C–H bond cleavage in ethanol and it is also responsible for carbon accumulation. On the other hand, CeO x is important for the deprotonation of ethanol/water to ethoxy and OH intermediates. The active state of CeO x is a Ce 3+(OH) x compound that results from extensive reduction by ethanol and the efficient dissociation of water. Additionally, we gain an important insight into the stability and selectivity of the catalyst by its effective water dissociation, where the accumulation of surface carbon can be mitigated by the increased presence of surface OH groups. As a result, the co-existence and cooperative interplay of Ni 0 and Ce 3+(OH) x through a metal–support interaction facilitate oxygen transfer, activation of ethanol/water as well as the removal of coke.« less

Hepatoprotective activity of Leptadenia reticulata stems against carbon tetrachloride-induced hepatotoxicity in rats

PubMed Central

Nema, Amit Kumar; Agarwal, Abhinav; Kashaw, Varsha

2011-01-01

Objective: To evaluate the hepatoprotective activity of ethanolic and aqueous extract of stems of Leptadenia reticulata (Retz.) Wight. and Arn. in carbon tetrachloride (CCl4)-induced hepatotoxicity in rats. Materials and Methods: The toxicant CCl4 was used to induce hepatotoxicity at a dose of 1.25 ml/kg as 1 : 1 mixture with olive oil. Ethanolic and aqueous extracts of L. reticulata stems were administered in the doses of 250 and 500 mg/kg/day orally for 7 days. Silymarin (50 mg/kg) was used as standard drug. The hepatoprotective effect of these extracts was evaluated by the assessment of biochemical parameters such as serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, alkaline phosphatase, total bilirubin, serum protein, and histopathological studies of the liver. Results: Treatment of animals with ethanolic and aqueous extracts significantly reduced the liver damage and the symptoms of liver injury by restoration of architecture of liver as indicated by lower levels of serum bilirubin and protein as compared with the normal and silymarin-treated groups. Histology of the liver sections confirmed that the extracts prevented hepatic damage induced by CCl4 showing the presence of normal hepatic cords, absence of necrosis, and fatty infiltration. Conclusion: The ethanolic and aqueous extracts of stems of L. reticulata showed significant hepatoprotective activity. The ethanolic extract is more potent in hepatoprotection in CCl4-indiced liver injury model as compared with aqueous extract. PMID:21713086

Consideration of black carbon and primary organic carbon emissions in life-cycle analysis of Greenhouse gas emissions of vehicle systems and fuels.

PubMed

Cai, Hao; Wang, Michael Q

2014-10-21

The climate impact assessment of vehicle/fuel systems may be incomplete without considering short-lived climate forcers of black carbon (BC) and primary organic carbon (POC). We quantified life-cycle BC and POC emissions of a large variety of vehicle/fuel systems with an expanded Greenhouse gases, Regulated Emissions, and Energy use in Transportation model developed at Argonne National Laboratory. Life-cycle BC and POC emissions have small impacts on life-cycle greenhouse gas (GHG) emissions of gasoline, diesel, and other fuel vehicles, but would add 34, 16, and 16 g CO2 equivalent (CO2e)/mile, or 125, 56, and 56 g CO2e/mile with the 100 or 20 year Global Warming Potentials of BC and POC emissions, respectively, for vehicles fueled with corn stover-, willow tree-, and Brazilian sugarcane-derived ethanol, mostly due to BC- and POC-intensive biomass-fired boilers in cellulosic and sugarcane ethanol plants for steam and electricity production, biomass open burning in sugarcane fields, and diesel-powered agricultural equipment for biomass feedstock production/harvest. As a result, life-cycle GHG emission reduction potentials of these ethanol types, though still significant, are reduced from those without considering BC and POC emissions. These findings, together with a newly expanded GREET version, help quantify the previously unknown impacts of BC and POC emissions on life-cycle GHG emissions of U.S. vehicle/fuel systems.

Alcohol reversibly disrupts TNF-α/TACE interactions in the cell membrane

PubMed Central

Song, Kejing; Zhao, Xue-Jun; Marrero, Luis; Oliver, Peter; Nelson, Steve; Kolls, Jay K

2005-01-01

Background Alcohol abuse has long been known to adversely affect innate and adaptive immune responses and pre-dispose to infections. One cellular mechanism responsible for this effect is alcohol-induced suppression of TNF-α (TNF) by mononuclear phagocytes. We have previously shown that alcohol in part inhibits TNF-α processing by TNF converting enzyme (TACE) in human monocytes. We hypothesized that the chain length of the alcohol is critical for post-transcriptional suppression of TNF secretion. Methods Due to the complex transcriptional and post-transcriptional regulation of TNF in macrophages, to specifically study TNF processing at the cell membrane we performed transient transfections of A549 cells with the TNF cDNA driven by the heterologous CMV promoter. TNF/TACE interactions at the cell surface were assessed using fluorescent resonance energy transfer (FRET) microscopy. Results The single carbon alcohol, methanol suppressed neither TNF secretion nor FRET efficiency between TNF and TACE. However, 2, 3, and 4 carbon alcohols were potent suppressors of TNF processing and FRET efficiency. The effect of ethanol, a 2-carbon alcohol was reversible. Conclusion These data show that inhibition of TNF-α processing by acute ethanol is a direct affect of ethanol on the cell membrane and is reversible upon cessation or metabolism. PMID:16246259

Electrocatalytic behavior of a nanocomposite of Ni/Pd supported by carbonized PVA nanofibers towards formic acid, ethanol and urea oxidation: A physicochemical and electro-analysis study

NASA Astrophysics Data System (ADS)

Mohamed, Ibrahim M. A.; Yasin, Ahmed S.; Barakat, Nasser A. M.; Song, Seung A.; Lee, Ha Eun; Kim, Seong Su

2018-03-01

A nanocomposite of Ni/Pd supported by carbonized poly-vinyl alcohol (PVA) nanofibers (NFs) was synthesized via electrospinning followed by calcination under an argon atmosphere. The as-synthesized NFs were studied using physicochemical analyses, such as field-emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTsbnd IR) and X-ray photoelectron spectroscopy (XPS), to investigate the morphology, crystallinity, effect of carbonization and surface chemistry of the NFs, respectively. Cyclic voltammetry (CV) and chronoamperometry (CA) were utilized to study the performance of the NFs towards electrooxidation reactions. The designed NFs present superior electrocatalytic behavior in an acid medium towards formic acid oxidation, as well as urea and ethanol oxidation in an alkaline medium. The electrocatalytic performance of the bimetallic NFs appears to arise from the assembly of bimetallic Ni/Pd@NFs based on PVA, which has hydroxyl groups. These hydroxyl groups can decrease the negative processes that occur as a result of metal-metal interactions, such as the aggregation process. This study introduces a novel non-precious electrocatalyst to facilitate the commercialization of fuel cells based on formic acid, urea and ethanol.

Change in soil organic carbon after five years of continuous winter wheat or switchgrass

USDA-ARS?s Scientific Manuscript database

Perennial grasses have been promoted to supply cellulose for ethanol production but possible consequences on soil organic carbon (SOC) should be assessed before adoption in a given region. Specific objectives were to (i) compare above-ground biomass C production and depth distribution of SOC conten...

Ambient pressure XPS and IRRAS investigation of ethanol steam reforming on Ni–CeO 2(111) catalysts: An in situ study of C–C and O–H bond scission

DOE PAGES

Liu, Zongyuan; Duchon, Tomas; Wang, Huanru; ...

2016-03-31

Ambient-Pressure X-ray Photoelectron Spectroscopy (AP-XPS) and Infrared Reflection Absorption Spectroscopy (AP-IRRAS) have been used to elucidate the active sites and mechanistic steps associated with the ethanol steam reforming reaction (ESR) over Ni–CeO 2(111) model catalysts. Our results reveal that surface layers of the ceria substrate are both highly reduced and hydroxylated under reaction conditions while the small supported Ni nanoparticles are present as Ni 0/NixC. A multifunctional, synergistic role is highlighted in which Ni, CeO x and the interface provide an ensemble effect in the active chemistry that leads to H 2. Ni 0 is the active phase leading tomore » both C–C and C–H bond cleavage in ethanol and it is also responsible for carbon accumulation. On the other hand, CeO x is important for the deprotonation of ethanol/water to ethoxy and OH intermediates. The active state of CeO x is a Ce 3+(OH) x compound that results from extensive reduction by ethanol and the efficient dissociation of water. Additionally, we gain an important insight into the stability and selectivity of the catalyst by its effective water dissociation, where the accumulation of surface carbon can be mitigated by the increased presence of surface OH groups. As a result, the co-existence and cooperative interplay of Ni 0 and Ce 3+(OH) x through a metal–support interaction facilitate oxygen transfer, activation of ethanol/water as well as the removal of coke.« less

Climate change and health costs of air emissions from biofuels and gasoline

PubMed Central

Hill, Jason; Polasky, Stephen; Nelson, Erik; Tilman, David; Huo, Hong; Ludwig, Lindsay; Neumann, James; Zheng, Haochi; Bonta, Diego

2009-01-01

Environmental impacts of energy use can impose large costs on society. We quantify and monetize the life-cycle climate-change and health effects of greenhouse gas (GHG) and fine particulate matter (PM2.5) emissions from gasoline, corn ethanol, and cellulosic ethanol. For each billion ethanol-equivalent gallons of fuel produced and combusted in the US, the combined climate-change and health costs are $469 million for gasoline, $472–952 million for corn ethanol depending on biorefinery heat source (natural gas, corn stover, or coal) and technology, but only $123–208 million for cellulosic ethanol depending on feedstock (prairie biomass, Miscanthus, corn stover, or switchgrass). Moreover, a geographically explicit life-cycle analysis that tracks PM2.5 emissions and exposure relative to U.S. population shows regional shifts in health costs dependent on fuel production systems. Because cellulosic ethanol can offer health benefits from PM2.5 reduction that are of comparable importance to its climate-change benefits from GHG reduction, a shift from gasoline to cellulosic ethanol has greater advantages than previously recognized. These advantages are critically dependent on the source of land used to produce biomass for biofuels, on the magnitude of any indirect land use that may result, and on other as yet unmeasured environmental impacts of biofuels. PMID:19188587

Evaluation of the organic matter sources using the δ13C composition of individual n-alkanes in sediments from Brazilian estuarine systems by GC/C/IRMS

NASA Astrophysics Data System (ADS)

Maioli, Otávio Luiz Gusso; de Oliveira, Cristiane Rossi; Dal Sasso, Marco Aurélio; Madureira, Luiz Augusto dos Santos; Azevedo, Débora de Almeida; de Aquino Neto, Francisco Radler

2012-12-01

The δ13C composition of individual n-alkanes (from C16 to C34) was measured from surface sediments of five Brazilian estuarine systems affected by different organic matter sources, such as harbor area, industries, urban centers and sugar cane crops, in order to determine the origins of the organic matter. The aliphatic hydrocarbon fraction was analyzed by gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS). The levels of n-alkanes in the studied areas ranged from 0.34 to 18.14 μg kg-1, being relatively low in comparison to high polluted environments. The Carbon Preference Index (CPI) calculated in the C23-C34 range indicates that n-alkanes are mainly inherited from cuticular waxes of higher plants. The δ13C composition of all n-alkanes detected in the sediment samples ranged from -39.6 to -18.3‰ showing different sources for the studied estuarine systems. Through Principal Component Analysis (PCA) it was possible to verify the petrogenic influence in the n-alkane sources, especially in the Paraíba do Sul sediment samples. Differences up to 15‰ of the δ13C values between n-alkanes of odd and even carbon number (C26 and C27) also indicated mixture of petrogenic and biogenic sources in Paraíba do Sul River. High (less negative) δ13C n-alkane values of odd carbon number were obtained from two sampling sites located close to an ethanol plant, indicating residues discharge of sugar cane (C4 plant). Influence of C3 plants that are the main components of dense ombrophile forest was observed in the Itajaí-Açu sediments by the decrease of δ13C (about 10‰ compared to the Paraíba do Sul River δ13C).

Adapting to alcohol: Dwarf hamster (Phodopus campbelli) ethanol consumption, sensitivity, and hoard fermentation.

PubMed

Lupfer, Gwen; Murphy, Eric S; Merculieff, Zoe; Radcliffe, Kori; Duddleston, Khrystyne N

2015-06-01

Ethanol consumption and sensitivity in many species are influenced by the frequency with which ethanol is encountered in their niches. In Experiment 1, dwarf hamsters (Phodopus campbelli) with ad libitum access to food and water consumed high amounts of unsweetened alcohol solutions. Their consumption of 15%, but not 30%, ethanol was reduced when they were fed a high-fat diet; a high carbohydrate diet did not affect ethanol consumption. In Experiment 2, intraperitoneal injections of ethanol caused significant dose-related motor impairment. Much larger doses administered orally, however, had no effect. In Experiment 3, ryegrass seeds, a common food source for wild dwarf hamsters, supported ethanol fermentation. Results of these experiments suggest that dwarf hamsters may have adapted to consume foods in which ethanol production naturally occurs. Copyright © 2015 Elsevier B.V. All rights reserved.

In silico profiling of Escherichia coli and Saccharomyces cerevisiae as terpenoid factories

PubMed Central

2013-01-01

Background Heterologous microbial production of rare plant terpenoids of medicinal or industrial interest is attracting more and more attention but terpenoid yields are still low. Escherichia coli and Saccharomyces cerevisiae are the most widely used heterologous hosts; a direct comparison of both hosts based on experimental data is difficult though. Hence, the terpenoid pathways of E. coli (via 1-deoxy-D-xylulose 5-phosphate, DXP) and S. cerevisiae (via mevalonate, MVA), the impact of the respective hosts metabolism as well as the impact of different carbon sources were compared in silico by means of elementary mode analysis. The focus was set on the yield of isopentenyl diphosphate (IPP), the general terpenoid precursor, to identify new metabolic engineering strategies for an enhanced terpenoid yield. Results Starting from the respective precursor metabolites of the terpenoid pathways (pyruvate and glyceraldehyde-3-phosphate for the DXP pathway and acetyl-CoA for the MVA pathway) and considering only carbon stoichiometry, the two terpenoid pathways are identical with respect to carbon yield. However, with glucose as substrate, the MVA pathway has a lower potential to supply terpenoids in high yields than the DXP pathway if the formation of the required precursors is taken into account, due to the carbon loss in the formation of acetyl-CoA. This maximum yield is further reduced in both hosts when the required energy and reduction equivalents are considered. Moreover, the choice of carbon source (glucose, xylose, ethanol or glycerol) has an effect on terpenoid yield with non-fermentable carbon sources being more promising. Both hosts have deficiencies in energy and redox equivalents for high yield terpenoid production leading to new overexpression strategies (heterologous enzymes/pathways) for an enhanced terpenoid yield. Finally, several knockout strategies are identified using constrained minimal cut sets enforcing a coupling of growth to a terpenoid yield which is higher than any yield published in scientific literature so far. Conclusions This study provides for the first time a comprehensive and detailed in silico comparison of the most prominent heterologous hosts E. coli and S. cerevisiae as terpenoid factories giving an overview on several promising metabolic engineering strategies paving the way for an enhanced terpenoid yield. PMID:24059635

Comparative transcriptome analysis reveals different strategies for degradation of steam-exploded sugarcane bagasse by Aspergillus niger and Trichoderma reesei.

PubMed

Borin, Gustavo Pagotto; Sanchez, Camila Cristina; de Santana, Eliane Silva; Zanini, Guilherme Keppe; Dos Santos, Renato Augusto Corrêa; de Oliveira Pontes, Angélica; de Souza, Aline Tieppo; Dal'Mas, Roberta Maria Menegaldo Tavares Soares; Riaño-Pachón, Diego Mauricio; Goldman, Gustavo Henrique; Oliveira, Juliana Velasco de Castro

2017-06-30

Second generation (2G) ethanol is produced by breaking down lignocellulosic biomass into fermentable sugars. In Brazil, sugarcane bagasse has been proposed as the lignocellulosic residue for this biofuel production. The enzymatic cocktails for the degradation of biomass-derived polysaccharides are mostly produced by fungi, such as Aspergillus niger and Trichoderma reesei. However, it is not yet fully understood how these microorganisms degrade plant biomass. In order to identify transcriptomic changes during steam-exploded bagasse (SEB) breakdown, we conducted a RNA-seq comparative transcriptome profiling of both fungi growing on SEB as carbon source. Particular attention was focused on CAZymes, sugar transporters, transcription factors (TFs) and other proteins related to lignocellulose degradation. Although genes coding for the main enzymes involved in biomass deconstruction were expressed by both fungal strains since the beginning of the growth in SEB, significant differences were found in their expression profiles. The expression of these enzymes is mainly regulated at the transcription level, and A. niger and T. reesei also showed differences in TFs content and in their expression. Several sugar transporters that were induced in both fungal strains could be new players on biomass degradation besides their role in sugar uptake. Interestingly, our findings revealed that in both strains several genes that code for proteins of unknown function and pro-oxidant, antioxidant, and detoxification enzymes were induced during growth in SEB as carbon source, but their specific roles on lignocellulose degradation remain to be elucidated. This is the first report of a time-course experiment monitoring the degradation of pretreated bagasse by two important fungi using the RNA-seq technology. It was possible to identify a set of genes that might be applied in several biotechnology fields. The data suggest that these two microorganisms employ different strategies for biomass breakdown. This knowledge can be exploited for the rational design of enzymatic cocktails and 2G ethanol production improvement.

Inhibition of growth of Zymomonas mobilis by model compounds found in lignocellulosic hydrolysates

PubMed Central

2013-01-01

Background During the pretreatment of biomass feedstocks and subsequent conditioning prior to saccharification, many toxic compounds are produced or introduced which inhibit microbial growth and in many cases, production of ethanol. An understanding of the toxic effects of compounds found in hydrolysate is critical to improving sugar utilization and ethanol yields in the fermentation process. In this study, we established a useful tool for surveying hydrolysate toxicity by measuring growth rates in the presence of toxic compounds, and examined the effects of selected model inhibitors of aldehydes, organic and inorganic acids (along with various cations), and alcohols on growth of Zymomonas mobilis 8b (a ZM4 derivative) using glucose or xylose as the carbon source. Results Toxicity strongly correlated to hydrophobicity in Z. mobilis, which has been observed in Escherichia coli and Saccharomyces cerevisiae for aldehydes and with some exceptions, organic acids. We observed Z. mobilis 8b to be more tolerant to organic acids than previously reported, although the carbon source and growth conditions play a role in tolerance. Growth in xylose was profoundly inhibited by monocarboxylic organic acids compared to growth in glucose, whereas dicarboxylic acids demonstrated little or no effects on growth rate in either substrate. Furthermore, cations can be ranked in order of their toxicity, Ca++ > > Na+ > NH4+ > K+. HMF (5-hydroxymethylfurfural), furfural and acetate, which were observed to contribute to inhibition of Z. mobilis growth in dilute acid pretreated corn stover hydrolysate, do not interact in a synergistic manner in combination. We provide further evidence that Z. mobilis 8b is capable of converting the aldehydes furfural, vanillin, 4-hydroxybenzaldehyde and to some extent syringaldehyde to their alcohol forms (furfuryl, vanillyl, 4-hydroxybenzyl and syringyl alcohol) during fermentation. Conclusions Several key findings in this report provide a mechanism for predicting toxic contributions of inhibitory components of hydrolysate and provide guidance for potential process development, along with potential future strain improvement and tolerance strategies. PMID:23837621

Impact of zinc supplementation on the improved fructose/xylose utilization and butanol production during acetone-butanol-ethanol fermentation.

PubMed

Wu, You-Duo; Xue, Chuang; Chen, Li-Jie; Bai, Feng-Wu

2016-01-01

Lignocellulosic biomass and dedicated energy crops such as Jerusalem artichoke are promising alternatives for biobutanol production by solventogenic clostridia. However, fermentable sugars such as fructose or xylose released from the hydrolysis of these feedstocks were subjected to the incomplete utilization by the strains, leading to relatively low butanol production and productivity. When 0.001 g/L ZnSO4·7H2O was supplemented into the medium containing fructose as sole carbon source, 12.8 g/L of butanol was achieved with butanol productivity of 0.089 g/L/h compared to only 4.5 g/L of butanol produced with butanol productivity of 0.028 g/L/h in the control without zinc supplementation. Micronutrient zinc also led to the improved butanol production up to 8.3 g/L derived from 45.2 g/L xylose as sole carbon source with increasing butanol productivity by 31.7%. Moreover, the decreased acids production was observed under the zinc supplementation condition, resulting in the increased butanol yields of 0.202 g/g-fructose and 0.184 g/g-xylose, respectively. Similar improvements were also observed with increasing butanol production by 130.2 % and 8.5 %, butanol productivity by 203.4% and 18.4%, respectively, in acetone-butanol-ethanol fermentations from sugar mixtures of fructose/glucose (4:1) and xylose/glucose (1:2) simulating the hydrolysates of Jerusalem artichoke tubers and corn stover. The results obtained from transcriptional analysis revealed that zinc may have regulatory mechanisms for the sugar transport and metabolism of Clostridium acetobutylicum L7. Therefore, micronutrient zinc supplementation could be an effective way for economic development of butanol production derived from these low-cost agricultural feedstocks. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Lactose-Inducible System for Metabolic Engineering of Clostridium ljungdahlii

DOE Office of Scientific and Technical Information (OSTI.GOV)

Banerjee, A; Leang, C; Ueki, T

2014-03-25

The development of tools for genetic manipulation of Clostridium ljungdahlii has increased its attractiveness as a chassis for autotrophic production of organic commodities and biofuels from syngas and microbial electrosynthesis and established it as a model organism for the study of the basic physiology of acetogenesis. In an attempt to expand the genetic toolbox for C. ljungdahlii, the possibility of adapting a lactose-inducible system for gene expression, previously reported for Clostridium perfringens, was investigated. The plasmid pAH2, originally developed for C. perfringens with a gusA reporter gene, functioned as an effective lactose-inducible system in C. ljungdahlii. Lactose induction of C.more » ljungdahlii containing pB1, in which the gene for the aldehyde/alcohol dehydrogenase AdhE1 was downstream of the lactose-inducible promoter, increased expression of adhE1 30-fold over the wild-type level, increasing ethanol production 1.5-fold, with a corresponding decrease in acetate production. Lactose-inducible expression of adhE1 in a strain in which adhE1 and the adhE1 homolog adhE2 had been deleted from the chromosome restored ethanol production to levels comparable to those in the wild-type strain. Inducing expression of adhE2 similarly failed to restore ethanol production, suggesting that adhE1 is the homolog responsible for ethanol production. Lactose-inducible expression of the four heterologous genes necessary to convert acetyl coenzyme A (acetyl-CoA) to acetone diverted ca. 60% of carbon flow to acetone production during growth on fructose, and 25% of carbon flow went to acetone when carbon monoxide was the electron donor. These studies demonstrate that the lactose-inducible system described here will be useful for redirecting carbon and electron flow for the biosynthesis of products more valuable than acetate. Furthermore, this tool should aid in optimizing microbial electrosynthesis and for basic studies on the physiology of acetogenesis.« less