Greater transportation energy and GHG offsets from bioelectricity than ethanol.

PubMed

Campbell, J E; Lobell, D B; Field, C B

2009-05-22

The quantity of land available to grow biofuel crops without affecting food prices or greenhouse gas (GHG) emissions from land conversion is limited. Therefore, bioenergy should maximize land-use efficiency when addressing transportation and climate change goals. Biomass could power either internal combustion or electric vehicles, but the relative land-use efficiency of these two energy pathways is not well quantified. Here, we show that bioelectricity outperforms ethanol across a range of feedstocks, conversion technologies, and vehicle classes. Bioelectricity produces an average of 81% more transportation kilometers and 108% more emissions offsets per unit area of cropland than does cellulosic ethanol. These results suggest that alternative bioenergy pathways have large differences in how efficiently they use the available land to achieve transportation and climate goals.

Experimental Validation of Hybrid Distillation-Vapor Permeation Process for Energy Efficient Ethanol-Water Separation

EPA Science Inventory

The energy demand of distillation-based systems for ethanol recovery and dehydration can be significant, particularly for dilute solutions. An alternative separation process integrating vapor stripping with a vapor compression step and a vapor permeation membrane separation step...

Experimental Validation of Hybrid Distillation-Vapor Permeation Process for Energy Efficient Ethanol-Water Separation

EPA Science Inventory

The energy demand of distillation-based systems for ethanol recovery and dehydration can be significant, particularly for dilute solutions. An alternative separation process integrating vapor stripping with a vapor compression step and a vapor permeation membrane separation step,...

Comparative analysis of the Performance and Emission Characteristics of ethanol-butanol-gasoline blends

NASA Astrophysics Data System (ADS)

Taneja, Sumit; Singh, Perminderjit, Dr; Singh, Gurtej

2018-02-01

Global warming and energy security being the global problems have shifted the focus of researchers on the renewable sources of energy which could replace petroleum products partially or as a whole. Ethanol and butanol are renewable sources of energy which can be produced through fermentation of biomass. A lot of research has already been done to develop suitable ethanol-gasoline blends. In contrast very little literature available on the butanol-gasoline blends. This research focuses on the comparison of ethanol-gasoline fuels with butanol-gasoline fuels with regard to the emission and performance in an SI engine. Experiments were conducted on a variable compression ratio SI engine at 1600 rpm and compression ratio 8. The experiments involved the measurement of carbon monoxide, carbon dioxide, oxides of nitrogen and unburned hydrocarbons emission and among performance parameters brake specific fuel consumption and brake thermal efficiency were recorded at three loads of 2.5kgs (25%), 5kgs (50%) and 7.5kgs (75%). Results show that ethanol and butanol content in gasoline have decreased brake specific fuel consumption, carbon monoxide and unburned hydrocarbon emissions while the brake thermal efficiency and oxides of nitrogen are increased. Results indicate thatbutanol-gasoline blends have improved brake specific fuel consumption, carbon monoxide emissions in an SI engine as compared to ethanol-gasoline blends. The carbon dioxide emissions and brake thermal efficiencies are comparable for ethanol-gasoline blends and butanol-gasoline blends. The butanol content has a more adverse effect on emissions of oxides of nitrogen than ethanol.

Evaluation of Gene Modification Strategies for the Development of Low-Alcohol-Wine Yeasts

PubMed Central

Kutyna, D. R.; Solomon, M. R.; Black, C. A.; Borneman, A.; Henschke, P. A.; Pretorius, I. S.; Chambers, P. J.

2012-01-01

Saccharomyces cerevisiae has evolved a highly efficient strategy for energy generation which maximizes ATP energy production from sugar. This adaptation enables efficient energy generation under anaerobic conditions and limits competition from other microorganisms by producing toxic metabolites, such as ethanol and CO2. Yeast fermentative and flavor capacity forms the biotechnological basis of a wide range of alcohol-containing beverages. Largely as a result of consumer demand for improved flavor, the alcohol content of some beverages like wine has increased. However, a global trend has recently emerged toward lowering the ethanol content of alcoholic beverages. One option for decreasing ethanol concentration is to use yeast strains able to divert some carbon away from ethanol production. In the case of wine, we have generated and evaluated a large number of gene modifications that were predicted, or known, to impact ethanol formation. Using the same yeast genetic background, 41 modifications were assessed. Enhancing glycerol production by increasing expression of the glyceraldehyde-3-phosphate dehydrogenase gene, GPD1, was the most efficient strategy to lower ethanol concentration. However, additional modifications were needed to avoid negatively affecting wine quality. Two strains carrying several stable, chromosomally integrated modifications showed significantly lower ethanol production in fermenting grape juice. Strain AWRI2531 was able to decrease ethanol concentrations from 15.6% (vol/vol) to 13.2% (vol/vol), whereas AWRI2532 lowered ethanol content from 15.6% (vol/vol) to 12% (vol/vol) in both Chardonnay and Cabernet Sauvignon juices. Both strains, however, produced high concentrations of acetaldehyde and acetoin, which negatively affect wine flavor. Further modifications of these strains allowed reduction of these metabolites. PMID:22729542

High-Octane Mid-Level Ethanol Blend Market Assessment

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

Johnson, Caley; Newes, Emily; Brooker, Aaron

2015-12-01

The United States government has been promoting increased use of biofuels, including ethanol from non-food feedstocks, through policies contained in the Energy Independence and Security Act of 2007. The objective is to enhance energy security, reduce greenhouse gas (GHG) emissions, and provide economic benefits. However, the United States has reached the ethanol blend wall, where more ethanol is produced domestically than can be blended into standard gasoline. Nearly all ethanol is blended at 10 volume percent (vol%) in gasoline. At the same time, the introduction of more stringent standards for fuel economy and GHG tailpipe emissions is driving research tomore » increase the efficiency of spark ignition (SI) engines. Advanced strategies for increasing SI engine efficiency are enabled by higher octane number (more highly knock-resistant) fuels. Ethanol has a research octane number (RON) of 109, compared to typical U.S. regular gasoline at 91-93. Accordingly, high RON ethanol blends containing 20 vol% to 40 vol% ethanol are being extensively studied as fuels that enable design of more efficient engines. These blends are referred to as high-octane fuel (HOF) in this report. HOF could enable dramatic growth in the U.S. ethanol industry, with consequent energy security and GHG emission benefits, while also supporting introduction of more efficient vehicles. HOF could provide the additional ethanol demand necessary for more widespread deployment of cellulosic ethanol. However, the potential of HOF can be realized only if it is adopted by the motor fuel marketplace. This study assesses the feasibility, economics, and logistics of this adoption by the four required participants--drivers, vehicle manufacturers, fuel retailers, and fuel producers. It first assesses the benefits that could motivate these participants to adopt HOF. Then it focuses on the drawbacks and barriers that these participants could face when adopting HOF and proposes strategies--including incentives and policies--to curtail these barriers. These curtailment strategies are grouped into scenarios that are then modeled to investigate their feasibility and explore the dynamics involved in HOF deployment. This report does not advocate for or against incentives or policies, but presents simulations of their effects.« less

HIGH PERMEABILITY MEMBRANES FOR THE DEHYDRATION OF LOW WATER CONTENT ETHANOL BY PERVAPORATION

EPA Science Inventory

Energy efficient dehydration of low water content ethanol is a challenge for the sustainable production of fuel-grade ethanol. Pervaporative membrane dehydration using a recently developed hydrophilic polymer membrane formulation consisting of a cross-linked mixture of poly(allyl...

Effects of steam pretreatment and co-production with ethanol on the energy efficiency and process economics of combined biogas, heat and electricity production from industrial hemp.

PubMed

Barta, Zsolt; Kreuger, Emma; Björnsson, Lovisa

2013-04-22

The study presented here has used the commercial flow sheeting program Aspen Plus™ to evaluate techno-economic aspects of large-scale hemp-based processes for producing transportation fuels. The co-production of biogas, district heat and power from chopped and steam-pretreated hemp, and the co-production of ethanol, biogas, heat and power from steam-pretreated hemp were analysed. The analyses include assessments of heat demand, energy efficiency and process economics in terms of annual cash flows and minimum biogas and ethanol selling prices (MBSP and MESP). Producing biogas, heat and power from chopped hemp has the highest overall energy efficiency, 84% of the theoretical maximum (based on lower heating values), providing that the maximum capacity of district heat is delivered. The combined production of ethanol, biogas, heat and power has the highest energy efficiency (49%) if district heat is not produced. Neither the inclusion of steam pretreatment nor co-production with ethanol has a large impact on the MBSP. Ethanol is more expensive to produce than biogas is, but this is compensated for by its higher market price. None of the scenarios examined are economically viable, since the MBSP (EUR 103-128 per MWh) is higher than the market price of biogas (EUR 67 per MWh). The largest contribution to the cost is the cost of feedstock. Decreasing the retention time in the biogas process for low solids streams by partly replacing continuous stirred tank reactors by high-rate bioreactors decreases the MBSP. Also, recycling part of the liquid from the effluent from anaerobic digestion decreases the MBSP. The production and prices of methane and ethanol influence the process economics more than the production and prices of electricity and district heat. To reduce the production cost of ethanol and biogas from biomass, the use of feedstocks that are cheaper than hemp, give higher output of ethanol and biogas, or combined production with higher value products are primarily suggested. Further, practical investigations on increased substrate concentration in biogas and ethanol production, recycling of the liquid in anaerobic digestion and separation of low solids flows into solid and a liquid fraction for improved reactor applications deserves further attention.

Effects of steam pretreatment and co-production with ethanol on the energy efficiency and process economics of combined biogas, heat and electricity production from industrial hemp

PubMed Central

2013-01-01

Background The study presented here has used the commercial flow sheeting program Aspen Plus™ to evaluate techno-economic aspects of large-scale hemp-based processes for producing transportation fuels. The co-production of biogas, district heat and power from chopped and steam-pretreated hemp, and the co-production of ethanol, biogas, heat and power from steam-pretreated hemp were analysed. The analyses include assessments of heat demand, energy efficiency and process economics in terms of annual cash flows and minimum biogas and ethanol selling prices (MBSP and MESP). Results Producing biogas, heat and power from chopped hemp has the highest overall energy efficiency, 84% of the theoretical maximum (based on lower heating values), providing that the maximum capacity of district heat is delivered. The combined production of ethanol, biogas, heat and power has the highest energy efficiency (49%) if district heat is not produced. Neither the inclusion of steam pretreatment nor co-production with ethanol has a large impact on the MBSP. Ethanol is more expensive to produce than biogas is, but this is compensated for by its higher market price. None of the scenarios examined are economically viable, since the MBSP (EUR 103–128 per MWh) is higher than the market price of biogas (EUR 67 per MWh). The largest contribution to the cost is the cost of feedstock. Decreasing the retention time in the biogas process for low solids streams by partly replacing continuous stirred tank reactors by high-rate bioreactors decreases the MBSP. Also, recycling part of the liquid from the effluent from anaerobic digestion decreases the MBSP. The production and prices of methane and ethanol influence the process economics more than the production and prices of electricity and district heat. Conclusions To reduce the production cost of ethanol and biogas from biomass, the use of feedstocks that are cheaper than hemp, give higher output of ethanol and biogas, or combined production with higher value products are primarily suggested. Further, practical investigations on increased substrate concentration in biogas and ethanol production, recycling of the liquid in anaerobic digestion and separation of low solids flows into solid and a liquid fraction for improved reactor applications deserves further attention. PMID:23607263

Energy efficiency analysis: biomass-to-wheel efficiency related with biofuels production, fuel distribution, and powertrain systems.

PubMed

Huang, Wei-Dong; Zhang, Y-H Percival

2011-01-01

Energy efficiency analysis for different biomass-utilization scenarios would help make more informed decisions for developing future biomass-based transportation systems. Diverse biofuels produced from biomass include cellulosic ethanol, butanol, fatty acid ethyl esters, methane, hydrogen, methanol, dimethyether, Fischer-Tropsch diesel, and bioelectricity; the respective powertrain systems include internal combustion engine (ICE) vehicles, hybrid electric vehicles based on gasoline or diesel ICEs, hydrogen fuel cell vehicles, sugar fuel cell vehicles (SFCV), and battery electric vehicles (BEV). We conducted a simple, straightforward, and transparent biomass-to-wheel (BTW) analysis including three separate conversion elements--biomass-to-fuel conversion, fuel transport and distribution, and respective powertrain systems. BTW efficiency is a ratio of the kinetic energy of an automobile's wheels to the chemical energy of delivered biomass just before entering biorefineries. Up to 13 scenarios were analyzed and compared to a base line case--corn ethanol/ICE. This analysis suggests that BEV, whose electricity is generated from stationary fuel cells, and SFCV, based on a hydrogen fuel cell vehicle with an on-board sugar-to-hydrogen bioreformer, would have the highest BTW efficiencies, nearly four times that of ethanol-ICE. In the long term, a small fraction of the annual US biomass (e.g., 7.1%, or 700 million tons of biomass) would be sufficient to meet 100% of light-duty passenger vehicle fuel needs (i.e., 150 billion gallons of gasoline/ethanol per year), through up to four-fold enhanced BTW efficiencies by using SFCV or BEV. SFCV would have several advantages over BEV: much higher energy storage densities, faster refilling rates, better safety, and less environmental burdens.

Energy Efficiency Analysis: Biomass-to-Wheel Efficiency Related with Biofuels Production, Fuel Distribution, and Powertrain Systems

PubMed Central

Huang, Wei-Dong; Zhang, Y-H Percival

2011-01-01

Background Energy efficiency analysis for different biomass-utilization scenarios would help make more informed decisions for developing future biomass-based transportation systems. Diverse biofuels produced from biomass include cellulosic ethanol, butanol, fatty acid ethyl esters, methane, hydrogen, methanol, dimethyether, Fischer-Tropsch diesel, and bioelectricity; the respective powertrain systems include internal combustion engine (ICE) vehicles, hybrid electric vehicles based on gasoline or diesel ICEs, hydrogen fuel cell vehicles, sugar fuel cell vehicles (SFCV), and battery electric vehicles (BEV). Methodology/Principal Findings We conducted a simple, straightforward, and transparent biomass-to-wheel (BTW) analysis including three separate conversion elements -- biomass-to-fuel conversion, fuel transport and distribution, and respective powertrain systems. BTW efficiency is a ratio of the kinetic energy of an automobile's wheels to the chemical energy of delivered biomass just before entering biorefineries. Up to 13 scenarios were analyzed and compared to a base line case – corn ethanol/ICE. This analysis suggests that BEV, whose electricity is generated from stationary fuel cells, and SFCV, based on a hydrogen fuel cell vehicle with an on-board sugar-to-hydrogen bioreformer, would have the highest BTW efficiencies, nearly four times that of ethanol-ICE. Significance In the long term, a small fraction of the annual US biomass (e.g., 7.1%, or 700 million tons of biomass) would be sufficient to meet 100% of light-duty passenger vehicle fuel needs (i.e., 150 billion gallons of gasoline/ethanol per year), through up to four-fold enhanced BTW efficiencies by using SFCV or BEV. SFCV would have several advantages over BEV: much higher energy storage densities, faster refilling rates, better safety, and less environmental burdens. PMID:21765941

Experimental Evaluation of Hybrid Distillation-Vapor Permeation Process for Efficient Ethanol Recovery from Ethanol-Water Mixtures

EPA Science Inventory

The energy demand of distillation-based systems for ethanol recovery and dehydration can be significant, particularly for dilute solutions [1]. An alternative separation process integrating vapor stripping with a vapor compression step and a vapor permeation membrane separation ...

Effect of ethanol-gasoline blends on small engine generator energy efficiency and exhaust emission.

PubMed

Lin, Wen-Yinn; Chang, Yuan-Yi; Hsieh, You-Ru

2010-02-01

This study was focused on fuel energy efficiency and pollution analysis of different ratios of ethanol-gasoline blended fuels (E0, E3, E6, and E9) under different loadings. In this research, the experimental system consisted of a small engine generator, a particulate matter measurement system, and an exhaust gas analyzer system. Different fuels, unleaded gasoline, and ethanol-gasoline blends (E0, E3, E6, and E9) were used to study their effects on the exhaust gas emission and were expressed as thermal efficiency of the small engine generator energy efficiency. The results suggested that particle number concentration increased as the engine loading increased; however, it decreased as the ethanol content in the blend increased. While using E6 as fuel, the carbon monoxide (CO) concentration was less than other fuels (E0, E3, and E9) for each engine loading. The average of CO concentration reduction by using E3, E6, and E9 is 42, 86, and 83%, respectively. Using an ethanol-gasoline blend led to a significant reduction in exhaust emissions by approximately 78.7, 97.5, and 89.46% of the mean average values of hydrocarbons (HCs) with E3, E6, and E9 fuels, respectively, for all engine loadings. Using an ethanol-gasoline blend led to a significant reduction in exhaust emissions by approximately 35, 86, and 77% of the mean average values of nitrogen oxides (NOx) with E3, E6, and E9 fuels, respectively, at each engine loading. The E6 fuel gave the best results of the exhaust emissions, and the E9 fuel gave the best results of the particle emissions and engine performance. The thermal efficiency of the small engine generator increased as the ethanol content in the blend increased and as the engine loading increased.

Energy efficiency of acetone, butanol, and ethanol (ABE) recovery by heat-integrated distillation.

PubMed

Grisales Diaz, Victor Hugo; Olivar Tost, Gerard

2018-03-01

Acetone, butanol, and ethanol (ABE) is an alternative biofuel. However, the energy requirement of ABE recovery by distillation is considered elevated (> 15.2 MJ fuel/Kg-ABE), due to the low concentration of ABE from fermentation broths (between 15 and 30 g/l). In this work, to reduce the energy requirements of ABE recovery, four processes of heat-integrated distillation were proposed. The energy requirements and economic evaluations were performed using the fermentation broths of several biocatalysts. Energy requirements of the processes with four distillation columns and three distillation columns were similar (between 7.7 and 11.7 MJ fuel/kg-ABE). Double-effect system (DED) with four columns was the most economical process (0.12-0.16 $/kg-ABE). ABE recovery from dilute solutions by DED achieved energy requirements between 6.1 and 8.7 MJ fuel/kg-ABE. Vapor compression distillation (VCD) reached the lowest energy consumptions (between 4.7 and 7.3 MJ fuel/kg-ABE). Energy requirements for ABE recovery DED and VCD were lower than that for integrated reactors. The energy requirements of ABE production were between 1.3- and 2.0-fold higher than that for alternative biofuels (ethanol or isobutanol). However, the energy efficiency of ABE production was equivalent than that for ethanol and isobutanol (between 0.71 and 0.76) because of hydrogen production in ABE fermentation.

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.

Ethanol production from SPORL-pretreated lodgepole pine: preliminary evaluation of mass balance and process energy efficiency.

PubMed

Zhu, J Y; Zhu, Wenyuan; Obryan, Patricia; Dien, Bruce S; Tian, Shen; Gleisner, Rolland; Pan, X J

2010-05-01

Lodgepole pine from forest thinnings is a potential feedstock for ethanol production. In this study, lodgepole pine was converted to ethanol with a yield of 276 L per metric ton of wood or 72% of theoretical yield. The lodgepole pine chips were directly subjected to sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) pretreatment and then disk-milled; the recovered cellulose substrate was quais-simultaneously saccharified enzymatically and fermented to ethanol using commercial cellulases and Saccharomyces cerevisiae D5A. The liquor stream from the pretreatment containing hydrolyzed sugars mainly from hemicelluloses was fermented by the same yeast strain after detoxification using an XAD resin column. The SPORL pretreatment was conducted at 180 degrees C for a period of 25 min with a liquor-to-wood ratio of 3:1 (v/w) in a laboratory digester. Three levels of sulfuric acid charge (0.0%, 1.4%, and 2.2% on an oven dried wood basis in w/w) and three levels of sodium bisulfite charge (0.0%, 4.0%, and 8.0% in w/w) were applied. Mechanical and thermal energy consumption for milling and pretreatment were determined. These data were used to determine the efficiency of sugar recoveries and net ethanol energy production values and to formulate a preliminary mass and energy balance.

Thermodynamic analysis of fermentation and anaerobic growth of baker's yeast for ethanol production.

PubMed

Teh, Kwee-Yan; Lutz, Andrew E

2010-05-17

Thermodynamic concepts have been used in the past to predict microbial growth yield. This may be the key consideration in many industrial biotechnology applications. It is not the case, however, in the context of ethanol fuel production. In this paper, we examine the thermodynamics of fermentation and concomitant growth of baker's yeast in continuous culture experiments under anaerobic, glucose-limited conditions, with emphasis on the yield and efficiency of bio-ethanol production. We find that anaerobic metabolism of yeast is very efficient; the process retains more than 90% of the maximum work that could be extracted from the growth medium supplied to the chemostat reactor. Yeast cells and other metabolic by-products are also formed, which reduces the glucose-to-ethanol conversion efficiency to less than 75%. Varying the specific ATP consumption rate, which is the fundamental parameter in this paper for modeling the energy demands of cell growth, shows the usual trade-off between ethanol production and biomass yield. The minimum ATP consumption rate required for synthesizing cell materials leads to biomass yield and Gibbs energy dissipation limits that are much more severe than those imposed by mass balance and thermodynamic equilibrium constraints. 2010 Elsevier B.V. All rights reserved.

The effect of a combined biological and thermo-mechanical pretreatment of wheat straw on energy yields in coupled ethanol and methane generation.

PubMed

Theuretzbacher, Franz; Blomqvist, Johanna; Lizasoain, Javier; Klietz, Lena; Potthast, Antje; Horn, Svein Jarle; Nilsen, Paal J; Gronauer, Andreas; Passoth, Volkmar; Bauer, Alexander

2015-10-01

Ethanol and biogas are energy carriers that could contribute to a future energy system independent of fossil fuels. Straw is a favorable bioenergy substrate as it does not compete with food or feed production. As straw is very resistant to microbial degradation, it requires a pretreatment to insure efficient conversion to ethanol and/or methane. This study investigates the effect of combining biological pretreatment and steam explosion on ethanol and methane yields in order to improve the coupled generation process. Results show that the temperature of the steam explosion pretreatment has a particularly strong effect on possible ethanol yields, whereas combination with the biological pretreatment showed no difference in overall energy yield. The highest overall energy output was found to be 10.86 MJ kg VS(-1) using a combined biological and steam explosion pretreatment at a temperature of 200°C. Copyright © 2015 Elsevier Ltd. All rights reserved.

Thermodynamic analysis of fuels in gas phase: ethanol, gasoline and ethanol - gasoline predicted by DFT method.

PubMed

Neto, A F G; Lopes, F S; Carvalho, E V; Huda, M N; Neto, A M J C; Machado, N T

2015-10-01

This paper presents a theoretical study using density functional theory to calculate thermodynamics properties of major molecules compounds at gas phase of fuels like gasoline, ethanol, and gasoline-ethanol mixture in thermal equilibrium on temperature range up to 1500 K. We simulated a composition of gasoline mixture with ethanol for a thorough study of thermal energy, enthalpy, Gibbs free energy, entropy, heat capacity at constant pressure with respect to temperature in order to study the influence caused by ethanol as an additive to gasoline. We used semi-empirical computational methods as well in order to know the efficiency of other methods to simulate fuels through this methodology. In addition, the ethanol influence through the changes in percentage fractions of chemical energy released in combustion reaction and the variations on thermal properties for autoignition temperatures of fuels was analyzed. We verified how ethanol reduces the chemical energy released by gasoline combustion and how at low temperatures the gas phase fuels in thermal equilibrium have similar thermodynamic behavior. Theoretical results were compared with experimental data, when available, and showed agreement. Graphical Abstract Thermodynamic analysis of fuels in gas phase.

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...

A study on emission characteristics of an EFI engine with ethanol blended gasoline fuels

NASA Astrophysics Data System (ADS)

He, Bang-Quan; Wang, Jian-Xin; Hao, Ji-Ming; Yan, Xiao-Guang; Xiao, Jian-Hua

The effect of ethanol blended gasoline fuels on emissions and catalyst conversion efficiencies was investigated in a spark ignition engine with an electronic fuel injection (EFI) system. The addition of ethanol to gasoline fuel enhances the octane number of the blended fuels and changes distillation temperature. Ethanol can decrease engine-out regulated emissions. The fuel containing 30% ethanol by volume can drastically reduce engine-out total hydrocarbon emissions (THC) at operating conditions and engine-out THC, CO and NO x emissions at idle speed, but unburned ethanol and acetaldehyde emissions increase. Pt/Rh based three-way catalysts are effective in reducing acetaldehyde emissions, but the conversion of unburned ethanol is low. Tailpipe emissions of THC, CO and NO x have close relation to engine-out emissions, catalyst conversion efficiency, engine's speed and load, air/fuel equivalence ratio. Moreover, the blended fuels can decrease brake specific energy consumption.

Renewable energy: energy from agricultural products

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

Not Available

1984-06-01

This study discusses major issues concerning fuels derived from agricultural products. Agricultural products, particularly sugarcane and corn, are currently meeting major energy needs in Florida. Recent figures indicate that about 10% of the gasoline sold in Florida is ethanol enriched. This gasohol contains a 10% mix of ethanol, which is generally produced from corn or sugarcane molasses. Sugarcane residues (bagasse) also supply most of the fuel to power Florida's large sugar processing industry. These products have the potential to play an expanded role in Florida's energy future. Principle areas of interest are: Growing crops such as napier grass or harvestingmore » water hyacinths to produce methane that can be substituted for natural gas; expanded use of sugar, starch, and industrial and agricultural wastes as raw materials for ethanol production; improved efficiency in conversion processes such as anaerobic digestion and fermentation. The Institute of Food and Agricultural Sciences at the University of Florida plays a leading national role in energy crops research, while Walt Disney World is using a demonstration project to convert water hyacinths into methane. Increased use of fuels produced from agricultural products depends largely on their costs compared to other fuels. Ethanol is currently attractive because of federal and state tax incentives. The growth potential of ethanol and methane is enhanced by the ease with which they can be blended with fossil fuels and thereby utilize the current energy distribution system. Neither ethanol nor methane appear able to compete in the free market for mass distribution at present, although studies indicate that genetic engineering and more efficient conversion processes may lower prices to cost effective levels. These fuels will be most cost effective in cases where waste products are utilized and the fuel is used close to the site of production.« less

Renewable energy: energy from agricultural products

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

Not Available

1984-06-01

This report discusses the major issues concerning fuels derived from agricultural products. Agricultural products, particularly sugarcane and corn, are currently meeting major energy needs in Florida. Recent figures indicate that about 10 percent of the gasoline sold in Florida is ethanol enriched. This gasohol contains a 10 percent mix of ethanol, which is generally produced from corn or sugarcane molasses. Sugarcane residues (bagasse) also supply most of the fuel to power Florida's large sugar processing industry. These products have the potential to play an expanded role in Florida's energy future. Principle areas of interest are: growing crops such as napiermore » grass or harvesting water hyacinths to produce methane that can be substituted for natural gas; expanded use of sugar, starch, and industrial and agricultural wastes as raw materials for ethanol production; and improved efficiency in conversion processes such as anaerobic digestion and fermentation. The Institute of Food and Agricultural Sciences at the University of Florida plays a leading national role in energy crops research, while Walt Disney World is using a demonstration project to convert water hyacinths into methane. Increased use of fuels produced from agricultural products depends largely on their costs compared to other fuels. Ethanol is currently attractive because of federal and state tax incentives. The growth potential of ethanol and methane is enhanced by the ease with which they can be blended with fossil fuels and thereby utilize the current energy distribution system. Neither ethanol nor methane appear able to compete in the free market for mass distribution at present, although studies indicate that genetic engineering and more efficient conversion processes may lower prices to cost effective levels. These fuels will be most cost effective in cases where waste products are utilized and the fuel is used close to the site of production.« less

Grain sorghum is a viable feedstock for ethanol production.

PubMed

Wang, D; Bean, S; McLaren, J; Seib, P; Madl, R; Tuinstra, M; Shi, Y; Lenz, M; Wu, X; Zhao, R

2008-05-01

Sorghum is a major cereal crop in the USA. However, sorghum has been underutilized as a renewable feedstock for bioenergy. The goal of this research was to improve the bioconversion efficiency for biofuels and biobased products from processed sorghum. The main focus was to understand the relationship among "genetics-structure-function-conversion" and the key factors impacting ethanol production, as well as to develop an energy life cycle analysis model (ELCAM) to quantify and prioritize the saving potential from factors identified in this research. Genetic lines with extremely high and low ethanol fermentation efficiency and some specific attributes that may be manipulated to improve the bioconversion rate of sorghum were identified. In general, ethanol yield increased as starch content increased. However, no linear relationship between starch content and fermentation efficiency was found. Key factors affecting the ethanol fermentation efficiency of sorghum include protein digestibility, level of extractable proteins, protein and starch interaction, mash viscosity, amount of phenolic compounds, ratio of amylose to amylopectin, and formation of amylose-lipid complexes in the mash. A platform ELCAM with a base case showed a positive net energy value (NEV) = 25,500 Btu/gal EtOH. ELCAM cases were used to identify factors that most impact sorghum use. For example, a yield increase of 40 bu/ac resulted in NEV increasing from 7 million to 12 million Btu/ac. An 8% increase in starch provided an incremental 1.2 million Btu/ac.

Well-to-Wheels Greenhouse Gas Emissions Analysis of High-Octane Fuels with Various Market Shares and Ethanol Blending Levels

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

Han, Jeongwoo; Elgowainy, Amgad; Wang, Michael

2015-07-14

In this study, we evaluated the impacts of producing HOF with a RON of 100, using a range of ethanol blending levels (E10, E25, and E40), vehicle efficiency gains, and HOF market penetration scenarios (3.4% to 70%), on WTW petroleum use and GHG emissions. In particular, we conducted LP modeling of petroleum refineries to examine the impacts of different HOF production scenarios on petroleum refining energy use and GHG emissions. We compared two cases of HOF vehicle fuel economy gains of 5% and 10% in terms of MPGGE to baseline regular gasoline vehicles. We incorporated three key factors in GREETmore » — (1) refining energy intensities of gasoline components for the various ethanol blending options and market shares, (2) vehicle efficiency gains, and (3) upstream energy use and emissions associated with the production of different crude types and ethanol — to compare the WTW GHG emissions of various HOF/vehicle scenarios with the business-as-usual baseline regular gasoline (87 AKI E10) pathway.« less

Efficient ethanol recovery from fermentation broths with integrated distillation-membrane process

EPA Science Inventory

The energy demand of distillation-molecular sieve systems for ethanol recovery/dehydration can be significant, particularly for dilute solutions. An alternative process integrating vapor stripping (like a beer still) with vapor compression and a vapor permeation membrane separati...

Cost analysis of cassava cellulose utilization scenarios for ethanol production on flowsheet simulation platform.

PubMed

Zhang, Jian; Fang, Zhenhong; Deng, Hongbo; Zhang, Xiaoxi; Bao, Jie

2013-04-01

Cassava cellulose accounts for one quarter of cassava residues and its utilization is important for improving the efficiency and profit in commercial scale cassava ethanol industry. In this study, three scenarios of cassava cellulose utilization for ethanol production were experimentally tested under same conditions and equipment. Based on the experimental results, a rigorous flowsheet simulation model was established on Aspen plus platform and the cost of cellulase enzyme and steam energy in the three cases was calculated. The results show that the simultaneous co-saccharification of cassava starch/cellulose and ethanol fermentation process (Co-SSF) provided a cost effective option of cassava cellulose utilization for ethanol production, while the utilization of cassava cellulose from cassava ethanol fermentation residues was not economically sound. Comparing to the current fuel ethanol selling price, the Co-SSF process may provide an important choice for enhancing cassava ethanol production efficiency and profit in commercial scale. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ethanol fermentation from molasses at high temperature by thermotolerant yeast Kluyveromyces sp. IIPE453 and energy assessment for recovery.

PubMed

Dasgupta, Diptarka; Ghosh, Prasenjit; Ghosh, Debashish; Suman, Sunil Kumar; Khan, Rashmi; Agrawal, Deepti; Adhikari, Dilip K

2014-10-01

High temperature ethanol fermentation from sugarcane molasses B using thermophilic Crabtree-positive yeast Kluyveromyces sp. IIPE453 was carried out in batch bioreactor system. Strain was found to have a maximum specific ethanol productivity of 0.688 g/g/h with 92 % theoretical ethanol yield. Aeration and initial sugar concentration were tuning parameters to regulate metabolic pathways of the strain for either cell mass or higher ethanol production during growth with an optimum sugar to cell ratio 33:1 requisite for fermentation. An assessment of ethanol recovery from fermentation broth via simulation study illustrated that distillation-based conventional recovery was significantly better in terms of energy efficiency and overall mass recovery in comparison to coupled solvent extraction-azeotropic distillation technique for the same.

Efficient process for producing saccharides and ethanol from a biomass feedstock

DOEpatents

Okeke, Benedict C.; Nanjundaswamy, Ananda K.

2017-04-11

Described herein is a process for producing saccharides and ethanol from biomass feedstock that includes (a) producing an enzyme composition by culturing a fungal strain(s) in the presence of a lignocellulosic medium, (b) using the enzyme composition to saccharify the biomass feedstock, and (c) fermenting the saccharified biomass feedstock to produce ethanol. The process is scalable and, in certain aspects, is capable of being deployed on farms, thereby allowing local production of saccharides and ethanol and resulting in a reduction of energy and other costs for farm operators. Optional steps to improve the biomass-to-fuel conversion efficiency are also contemplated, as are uses for byproducts of the process described herein.

Starch saccharification and fermentation of uncooked sweet potato roots for fuel ethanol production.

PubMed

Zhang, Peng; Chen, Caifa; Shen, Yanhu; Ding, Tielin; Ma, Daifu; Hua, Zichun; Sun, Dongxu

2013-01-01

An energy-saving ethanol fermentation technology was developed using uncooked fresh sweet potato as raw material. A mutant strain of Aspergillus niger isolated from mildewed sweet potato was used to produce abundant raw starch saccharification enzymes for treating uncooked sweet potato storage roots. The viscosity of the fermentation paste of uncooked sweet potato roots was lower than that of the cooked roots. The ethanol fermentation was carried out by Zymomonas mobilis, and 14.4 g of ethanol (87.2% of the theoretical yield) was produced from 100g of fresh sweet potato storage roots. Based on this method, an energy-saving, high efficient and environment-friendly technology can be developed for large-scale production of fuel ethanol from sweet potato roots. Copyright © 2012 Elsevier Ltd. All rights reserved.

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.

Ethanol production from SPORL-pretreated lodgepole pine : preliminary evaluation of mass balance and process energy efficiency

Treesearch

Junyong Zhu; Wenyuan Zhu; Patricia OBryan; Bruce S. Dien; Shen Tian; Roland Gleisner; X.J. Pan

2010-01-01

Lodgepole pine from forest thinnings is a potential feedstock for ethanol production. In this study, lodgepole pine was converted to ethanol with a yield of 276 L per metric ton of wood or 72% of theoretical yield. The lodgepole pine chips were directly subjected to sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) pretreatment and then disk-...

Efficient ethanol recovery from fermentation broths with integrated distillation-vapor permeation hybrid process

EPA Science Inventory

The energy demand of distillation-molecular sieve systems for ethanol recovery/dehydration can be significant, particularly for dilute solutions. An alternative hybrid process integrating vapor stripping (like a beer still) with vapor compression and a vapor permeation membrane s...

Summary of High-Octane Mid-Level Ethanol Blends Study

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

Theiss, Timothy J.; Alleman, Teresa; Brooker, Aaron

Original equipment manufacturers (OEMs) of light-duty vehicles are pursuing a broad portfolio of technologies to reduce CO 2 emissions and improve fuel economy. Central to this effort is higher efficiency spark ignition (SI) engines, including technologies reliant on higher compression ratios and fuels with improved anti-knock properties, such as gasoline with significantly increased octane numbers. Ethanol has an inherently high octane number and would be an ideal octane booster for lower-octane petroleum blendstocks. In fact, recently published data from Department of Energy (DOE) national laboratories (Splitter and Szybist, 2014a, 2014b; Szybist, 2010; Szybist and West, 2013) and OEMs (Anderson, 2013)more » and discussions with the U.S. Environmental Protection Agency (EPA) suggest the potential of a new high octane fuel (HOF) with 25–40 vol % of ethanol to assist in reaching Renewable Fuel Standard (RFS2) and greenhouse gas (GHG) emissions goals. This mid-level ethanol content fuel, with a research octane number (RON) of about 100, appears to enable efficiency improvements in a suitably calibrated and designed engine/vehicle system that are sufficient to offset its lower energy density (Jung, 2013; Thomas, et al, 2015). This efficiency improvement would offset the tank mileage (range) loss typically seen for ethanol blends in conventional gasoline and flexible-fuel vehicles (FFVs). The prospects for such a fuel are additionally attractive because it can be used legally in over 18 million FFVs currently on the road. Thus the legacy FFV fleet can serve as a bridge by providing a market for the new fuel immediately, so that future vehicles will have improved efficiency as the new fuel becomes widespread. In this way, HOF can simultaneously help improve fuel economy while expanding the ethanol market in the United States via a growing market for an ethanol blend higher than E10. The DOE Bioenergy Technologies Office initiated a collaborative research program between Oak Ridge National Laboratory (ORNL), the National Renewable Energy Laboratory (NREL), and Argonne National Laboratory (ANL) to investigate HOF in late 2013. The program objective was to provide a quantitative picture of the barriers to adoption of HOF and the highly efficient vehicles it enables, and to quantify the potential environmental and economic benefits of the technology.« less

Energy efficient of ethanol recovery in pervaporation membrane bioreactor with mechanical vapor compression eliminating the cold traps.

PubMed

Fan, Senqing; Xiao, Zeyi; Li, Minghai

2016-07-01

An energy efficient pervaporation membrane bioreactor with mechanical vapor compression was developed for ethanol recovery during the process of fermentation coupled with pervaporation. Part of the permeate vapor at the membrane downstream under the vacuum condition was condensed by running water at the first condenser and the non-condensed vapor enriched with ethanol was compressed to the atmospheric pressure and pumped into the second condenser, where the vapor was easily condensed into a liquid by air. Three runs of fermentation-pervaporation experiment have been carried out lasting for 192h, 264h and 360h respectively. Complete vapor recovery validated the novel pervaporation membrane bioreactor. The total flux of the polydimethylsiloxane (PDMS) membrane was in the range of 350gm(-2)h(-1) and 600gm(-2)h(-1). Compared with the traditional cold traps condensation, mechanical vapor compression behaved a dominant energy saving feature. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ethanol for a sustainable energy future.

PubMed

Goldemberg, José

2007-02-09

Renewable energy is one of the most efficient ways to achieve sustainable development. Increasing its share in the world matrix will help prolong the existence of fossil fuel reserves, address the threats posed by climate change, and enable better security of the energy supply on a global scale. Most of the "new renewable energy sources" are still undergoing large-scale commercial development, but some technologies are already well established. These include Brazilian sugarcane ethanol, which, after 30 years of production, is a global energy commodity that is fully competitive with motor gasoline and appropriate for replication in many countries.

[Life cycle assessment of energy consumption and greenhouse gas emissions of cellulosic ethanol from corn stover].

PubMed

Tian, Wang; Liao, Cuiping; Li, Li; Zhao, Daiqing

2011-03-01

Life Cycle Assessment (LCA) is the only standardized tool currently used to assess environmental loads of products and processes. The life cycle analysis, as a part of LCA, is a useful and powerful methodology for studying life cycle energy efficiency and life cycle GHG emission. To quantitatively explain the potential of energy saving and greenhouse gas (GHG) emissions reduction of corn stover-based ethanol, we analyzed life cycle energy consumption and GHG emissions of corn stover-based ethanol by the method of life cycle analysis. The processes are dilute acid prehydrolysis and enzymatic hydrolysis. The functional unit was defined as 1 km distance driven by the vehicle. Results indicated: compared with gasoline, the corn stover-based E100 (100% ethanol) and E10 (a blend of 10% ethanol and 90% gasoline by volume) could reduce life cycle fossil energy consumption by 79.63% and 6.25% respectively, as well as GHG emissions by 53.98% and 6.69%; the fossil energy consumed by biomass stage was 68.3% of total fossil energy input, N-fertilizer and diesel were the main factors which contributed 45.78% and 33.26% to biomass stage; electricity production process contributed 42.06% to the net GHG emissions, the improvement of technology might reduce emissions markedly.

Ethanol or bioelectricity? Life cycle assessment of lignocellulosic bioenergy use in light-duty vehicles.

PubMed

Luk, Jason M; Pourbafrani, Mohammad; Saville, Bradley A; MacLean, Heather L

2013-09-17

Our study evaluates life cycle energy use and GHG emissions of lignocellulosic ethanol and bioelectricity use in U.S. light-duty vehicles. The well-to-pump, pump-to-wheel, and vehicle cycle stages are modeled. All ethanol (E85) and bioelectricity pathways have similar life cycle fossil energy use (~ 100 MJ/100 vehicle kilometers traveled (VKT)) and net GHG emissions (~5 kg CO2eq./100 VKT), considerably lower (65-85%) than those of reference gasoline and U.S. grid-electricity pathways. E85 use in a hybrid vehicle and bioelectricity use in a fully electric vehicle also have similar life cycle biomass and total energy use (~ 350 and ~450 MJ/100 VKT, respectively); differences in well-to-pump and pump-to-wheel efficiencies can largely offset each other. Our energy use and net GHG emissions results contrast with findings in literature, which report better performance on these metrics for bioelectricity compared to ethanol. The primary source of differences in the studies is related to our development of pathways with comparable vehicle characteristics. Ethanol or vehicle electrification can reduce petroleum use, while bioelectricity may displace nonpetroleum energy sources. Regional characteristics may create conditions under which either ethanol or bioelectricity may be the superior option; however, neither has a clear advantage in terms of GHG emissions or energy use.

Biofuel production system with operation flexibility: Evaluation of economic and environmental performance under external disturbance

NASA Astrophysics Data System (ADS)

Kou, Nannan

Biomass derived liquid hydrocarbon fuel (biofuel) has been accepted as an effective way to mitigate the reliance on petroleum and reduce the greenhouse gas emissions. An increasing demand for second generation biofuels, produced from ligno-cellulosic feedstock and compatible with current infrastructure and vehicle technologies, addresses two major challenges faced by the current US transportation sector: energy security and global warming. However, biofuel production is subject to internal disturbances (feedstock supply and commodity market) and external factors (energy market). The biofuel industry has also heavily relied on government subsidy during the early development stages. In this dissertation, I investigate how to improve the economic and environmental performance of biorefineries (and biofuel plant), as well as enhance its survivability under the external disturbances. Three types of disturbance are considered: (1) energy market fluctuation, (2) subsidy policy uncertainty, and (3) extreme weather conditions. All three factors are basically volatile, dynamic, and even unpredictable, which makes them difficult to model and have been largely ignored to date. Instead, biofuel industry and biofuel research are intensively focused on improving feedstock conversion efficiency and capital cost efficiency while assuming these advancements alone will successfully generate higher profit and thus foster the biofuel industry. The collapse of the largest corn ethanol biofuel company, Verasun Energy, in 2008 calls into question this efficiency-driven approach. A detailed analysis has revealed that although the corn ethanol plants operated by Verasun adopted the more efficient (i.e. higher ethanol yield per bushel of corn and lower capital cost) dry-mill technology, they could not maintain a fair profit margin under fluctuating market condition which made ethanol production unprofitable. This is because dry-mill plant converts a single type of biomass feedstock (corn grain) into a single primary product (ethanol). The traditional lower efficient (i.e. lower ethanol yield per bushel of corn and higher capital cost) wet-mill plant has a more diverse and adjustable product portfolio i.e. corn syrup, starch, and ethanol. The fact that only the dry-mill corn ethanol plants have bankrupted while the wet-mill corn ethanol plants have survived the late 2000s economy recession suggests that the higher conversion efficiency achieved by the dry-mill production mode has jeopardized operational flexibility, a design operational feature I agree that is indispensable for the biofuel plant's long term profit and viability. Based on the analysis of corn ethanol production, operational flexibility has been proposed as a key strategy for the next generation biofuel plants to improve its lifetime economic performance, as well as to enhance its survivability under external disturbances. This strategy requires the biofuel plant to adopt a flexible feedstock management, making it possible to utilize alternative types of biomass feedstock when the primary feedstock supply is disturbed. Biofuel plants also need to produce a wider range of final products that could meet the preference variation that either comes from the energy market or from the subsidy policy. Aspen Plus model based numerical simulations have been carried out for a thermochemical ethanol plant and a Fischer Tropsch plant (both are assumed to be located in southwest Indiana) to test this strategy under the external disturbances of extreme weather impact, different energy price projections and various subsidy policy combinations. For the thermochemical ethanol plant, effects of extreme weather conditions are mainly evaluated. It has been shown that this strategy could effectively increase the net present value of the biofuel plant and significantly decrease the GHG emission comparing with the traditional single-feedstock strategy, when the extreme weather conditions are considered. It has also been demonstrated that this strategy could significantly decrease the possibility for the biofuel plant to bankrupt. For the Fischer Tropsch diesel plant, all the three external disturbances have been examined. It has been learned that operational flexibility through full capacity power co-generation, flexible feedstock management and hydrogen production by natural gas autothermal reforming could maximize the net present value under the influence of the external disturbances. Thus it is suggested that the future biofuel plant should adopt operational flexibility to increase the lifetime economic performance and to enhance the survivability under the influence of external disturbance.

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.

Bioconversion of Sugarcane Biomass into Ethanol: An Overview about Composition, Pretreatment Methods, Detoxification of Hydrolysates, Enzymatic Saccharification, and Ethanol Fermentation

PubMed Central

Canilha, Larissa; Chandel, Anuj Kumar; Suzane dos Santos Milessi, Thais; Antunes, Felipe Antônio Fernandes; Luiz da Costa Freitas, Wagner; das Graças Almeida Felipe, Maria; da Silva, Silvio Silvério

2012-01-01

Depleted supplies of fossil fuel, regular price hikes of gasoline, and environmental damage have necessitated the search for economic and eco-benign alternative of gasoline. Ethanol is produced from food/feed-based substrates (grains, sugars, and molasses), and its application as an energy source does not seem fit for long term due to the increasing fuel, food, feed, and other needs. These concerns have enforced to explore the alternative means of cost competitive and sustainable supply of biofuel. Sugarcane residues, sugarcane bagasse (SB), and straw (SS) could be the ideal feedstock for the second-generation (2G) ethanol production. These raw materials are rich in carbohydrates and renewable and do not compete with food/feed demands. However, the efficient bioconversion of SB/SS (efficient pretreatment technology, depolymerization of cellulose, and fermentation of released sugars) remains challenging to commercialize the cellulosic ethanol. Among the technological challenges, robust pretreatment and development of efficient bioconversion process (implicating suitable ethanol producing strains converting pentose and hexose sugars) have a key role to play. This paper aims to review the compositional profile of SB and SS, pretreatment methods of cane biomass, detoxification methods for the purification of hydrolysates, enzymatic hydrolysis, and the fermentation of released sugars for ethanol production. PMID:23251086

Environmental, economic, and energetic costs and benefits of biodiesel and ethanol biofuels.

PubMed

Hill, Jason; Nelson, Erik; Tilman, David; Polasky, Stephen; Tiffany, Douglas

2006-07-25

Negative environmental consequences of fossil fuels and concerns about petroleum supplies have spurred the search for renewable transportation biofuels. To be a viable alternative, a biofuel should provide a net energy gain, have environmental benefits, be economically competitive, and be producible in large quantities without reducing food supplies. We use these criteria to evaluate, through life-cycle accounting, ethanol from corn grain and biodiesel from soybeans. Ethanol yields 25% more energy than the energy invested in its production, whereas biodiesel yields 93% more. Compared with ethanol, biodiesel releases just 1.0%, 8.3%, and 13% of the agricultural nitrogen, phosphorus, and pesticide pollutants, respectively, per net energy gain. Relative to the fossil fuels they displace, greenhouse gas emissions are reduced 12% by the production and combustion of ethanol and 41% by biodiesel. Biodiesel also releases less air pollutants per net energy gain than ethanol. These advantages of biodiesel over ethanol come from lower agricultural inputs and more efficient conversion of feedstocks to fuel. Neither biofuel can replace much petroleum without impacting food supplies. Even dedicating all U.S. corn and soybean production to biofuels would meet only 12% of gasoline demand and 6% of diesel demand. Until recent increases in petroleum prices, high production costs made biofuels unprofitable without subsidies. Biodiesel provides sufficient environmental advantages to merit subsidy. Transportation biofuels such as synfuel hydrocarbons or cellulosic ethanol, if produced from low-input biomass grown on agriculturally marginal land or from waste biomass, could provide much greater supplies and environmental benefits than food-based biofuels.

Environmental, economic, and energetic costs and benefits of biodiesel and ethanol biofuels

PubMed Central

Hill, Jason; Nelson, Erik; Tilman, David; Polasky, Stephen; Tiffany, Douglas

2006-01-01

Negative environmental consequences of fossil fuels and concerns about petroleum supplies have spurred the search for renewable transportation biofuels. To be a viable alternative, a biofuel should provide a net energy gain, have environmental benefits, be economically competitive, and be producible in large quantities without reducing food supplies. We use these criteria to evaluate, through life-cycle accounting, ethanol from corn grain and biodiesel from soybeans. Ethanol yields 25% more energy than the energy invested in its production, whereas biodiesel yields 93% more. Compared with ethanol, biodiesel releases just 1.0%, 8.3%, and 13% of the agricultural nitrogen, phosphorus, and pesticide pollutants, respectively, per net energy gain. Relative to the fossil fuels they displace, greenhouse gas emissions are reduced 12% by the production and combustion of ethanol and 41% by biodiesel. Biodiesel also releases less air pollutants per net energy gain than ethanol. These advantages of biodiesel over ethanol come from lower agricultural inputs and more efficient conversion of feedstocks to fuel. Neither biofuel can replace much petroleum without impacting food supplies. Even dedicating all U.S. corn and soybean production to biofuels would meet only 12% of gasoline demand and 6% of diesel demand. Until recent increases in petroleum prices, high production costs made biofuels unprofitable without subsidies. Biodiesel provides sufficient environmental advantages to merit subsidy. Transportation biofuels such as synfuel hydrocarbons or cellulosic ethanol, if produced from low-input biomass grown on agriculturally marginal land or from waste biomass, could provide much greater supplies and environmental benefits than food-based biofuels. PMID:16837571

From the Cover: Environmental, economic, and energetic costs and benefits of biodiesel and ethanol biofuels

NASA Astrophysics Data System (ADS)

Hill, Jason; Nelson, Erik; Tilman, David; Polasky, Stephen; Tiffany, Douglas

2006-07-01

Negative environmental consequences of fossil fuels and concerns about petroleum supplies have spurred the search for renewable transportation biofuels. To be a viable alternative, a biofuel should provide a net energy gain, have environmental benefits, be economically competitive, and be producible in large quantities without reducing food supplies. We use these criteria to evaluate, through life-cycle accounting, ethanol from corn grain and biodiesel from soybeans. Ethanol yields 25% more energy than the energy invested in its production, whereas biodiesel yields 93% more. Compared with ethanol, biodiesel releases just 1.0%, 8.3%, and 13% of the agricultural nitrogen, phosphorus, and pesticide pollutants, respectively, per net energy gain. Relative to the fossil fuels they displace, greenhouse gas emissions are reduced 12% by the production and combustion of ethanol and 41% by biodiesel. Biodiesel also releases less air pollutants per net energy gain than ethanol. These advantages of biodiesel over ethanol come from lower agricultural inputs and more efficient conversion of feedstocks to fuel. Neither biofuel can replace much petroleum without impacting food supplies. Even dedicating all U.S. corn and soybean production to biofuels would meet only 12% of gasoline demand and 6% of diesel demand. Until recent increases in petroleum prices, high production costs made biofuels unprofitable without subsidies. Biodiesel provides sufficient environmental advantages to merit subsidy. Transportation biofuels such as synfuel hydrocarbons or cellulosic ethanol, if produced from low-input biomass grown on agriculturally marginal land or from waste biomass, could provide much greater supplies and environmental benefits than food-based biofuels. corn | soybean | life-cycle accounting | agriculture | fossil fuel

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.

Integrated distillation-membrane process for bio-ethanol and bio-butanol recovery from actual fermentation broths: Separation energy efficiency and fate of secondary fermentation products

EPA Science Inventory

A hybrid process integrating vapor stripping with vapor compression and vapor permeation membrane separation, termed Membrane Assisted Vapor Stripping (MAVS), was evaluated for recovery and dehydration of ethanol and/or 1-butanol from aqueous solution as an alternative to convent...

Synthesis of zeolite from rice husk ash waste of brick industries as hydrophobic adsorbent for fuel grade ethanol purification

NASA Astrophysics Data System (ADS)

Purnomo, A.; Alhanif, M.; Khotimah, C.; Zuhra, UA; Putri, BR; Kumoro, AC

2017-11-01

A lot of researchers have devoted on ethanol utilization as renewable energy to substitute petroleum based gasoline. When ethanol is being used as a new fuel candidate, it should have at least of 99.5% purity. Usually produced via sugar fermentation process, further purification of ethanol from other components in fermentation broth to obtain its fuel grade is a crucial step. The purpose of this research is to produce synthetic zeolite as hydrophobic adsorbent from rice husk ash for ethanol-water separation and to investigate the influence of weight, adsorption time and initial ethanol concentration on zeolite adsorption capacity. This research consisted of rice husk silica extraction, preparation of hydrophobic zeolite adsorbent, physical characterization using SEM, EDX and adsorption test for an ethanol-water solution. Zeolite with highest adsorption capacity was obtained with 15: 1 alumina silica composition. The best adsorption condition was achieved when 4-gram hydrophobic zeolite applied for adsorption of 100 mL of 10% (v/v) ethanol-water solution for 120 minutes, which resulted in ethanol with 98.93% (v/v) purity. The hydrophobic zeolite from rice husk ash is a potential candidate as an efficient adsorbent to purify raw ethanol into fuel grade ethanol. Implementation of this new adsorbent for ethanol production in commercial scale may reduce the energy consumption of that usually used for the distillation processes.

Determining the Return of Energy Efficiency Investments in Domestic and Deployed Military Installations

DTIC Science & Technology

2007-12-01

Ventilation, and Air Conditioning IED Improvised Explosive Device IG DoD Inspector General, Department of Defense IGA Investment Grade Audit JLTV...that certain energy efficient improvements will be achieved (Hansen, 2003). Investment Grade Audit (IGA). Based on the premise that energy...low- grade propane; and a modified diesel engine that can burn gas, ethanol, and diesel fuel in variable proportions (Hamilton, 2007). The TGER

Very high gravity (VHG) ethanolic brewing and fermentation: a research update.

PubMed

Puligundla, Pradeep; Smogrovicova, Daniela; Obulam, Vijaya Sarathi Reddy; Ko, Sanghoon

2011-09-01

There have been numerous developments in ethanol fermentation technology since the beginning of the new millennium as ethanol has become an immediate viable alternative to fast-depleting crude reserves as well as increasing concerns over environmental pollution. Nowadays, although most research efforts are focused on the conversion of cheap cellulosic substrates to ethanol, methods that are cost-competitive with gasoline production are still lacking. At the same time, the ethanol industry has engaged in implementing potential energy-saving, productivity and efficiency-maximizing technologies in existing production methods to become more viable. Very high gravity (VHG) fermentation is an emerging, versatile one among such technologies offering great savings in process water and energy requirements through fermentation of higher concentrations of sugar substrate and, therefore, increased final ethanol concentration in the medium. The technology also allows increased fermentation efficiency, without major alterations to existing facilities, by efficient utilization of fermentor space and elimination of known losses. This comprehensive research update on VHG technology is presented in two main sections, namely VHG brewing, wherein the effects of nutrients supplementation, yeast pitching rate, flavour compound synthesis and foam stability under increased wort gravities are discussed; and VHG bioethanol fermentation studies. In the latter section, aspects related to the role of osmoprotectants and nutrients in yeast stress reduction, substrates utilized/tested so far, including saccharide (glucose, sucrose, molasses, etc.) and starchy materials (wheat, corn, barley, oats, etc.), and mash viscosity issues in VHG bioethanol production are detailed. Thereafter, topics common to both areas such as process optimization studies, mutants and gene level studies, immobilized yeast applications, temperature effect, reserve carbohydrates profile in yeast, and economic aspects are discussed and future prospects are summarized.

Breaking the Biological Barriers to Cellulosic Ethanol: A Joint Research Agenda

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

Houghton, John; Weatherwax, Sharlene; Ferrell, John

2006-06-07

The Biomass to Biofuels Workshop, held December 7–9, 2005, was convened by the Department of Energy’s Office of Biological and Environmental Research in the Office of Science; and the Office of the Biomass Program in the Office of Energy Efficiency and Renewable Energy. The purpose was to define barriers and challenges to a rapid expansion of cellulosic-ethanol production and determine ways to speed solutions through concerted application of modern biology tools as part of a joint research agenda. Although the focus was ethanol, the science applies to additional fuels that include biodiesel and other bioproducts or coproducts having critical rolesmore » in any deployment scheme.« less

Refeeding after acute food restriction: differential reduction in preference for ethanol and ethanol-paired flavors in selectively bred rats.

PubMed

Dess, Nancy K; Chapman, Clinton D; Cousins, Laura A; Monroe, Derek C; Nguyen, Phuong

2013-01-17

Rats' voluntary ethanol intake varies with dispositional factors and energy status. The joint influences of these were of interest here. We previously reported that rats selectively bred for high voluntary saccharin intake (HiS) consume more ethanol and express more robust conditioning of preference for flavors paired with voluntarily consumed ethanol than do low-saccharin consuming counterparts (LoS). Three new experiments examined the effect of refeeding after an episode of food restriction on ethanol intake and on preference for ethanol-paired flavors in HiS and LoS rats. A 48-h episode of food restriction with wheel running reduced intake of and preference for 4% ethanol (Exp. 1a) and preference for an ethanol-paired flavor (Exp. 1b) during refeeding. Food restriction alone was sufficient to reduce the flavor preference (Exp. 2). Adding fat to the refeeding diet or extending the food restriction period exacerbated the effect (Exp. 3), yielding a frank aversion to ethanol-paired flavors in LoS rats. These studies indicate that rebound from negative energy balance shifts responses to ethanol-associated cues from preference toward aversion. Analyses of bodyweight changes and caloric intake during refeeding support this conclusion and further suggest that lower metabolic efficiency may be a marker for enhanced preference mutability. Copyright © 2012 Elsevier Inc. All rights reserved.

Bioelectricity versus bioethanol from sugarcane bagasse: is it worth being flexible?

PubMed Central

2013-01-01

Background Sugarcane is the most efficient crop for production of (1G) ethanol. Additionally, sugarcane bagasse can be used to produce (2G) ethanol. However, the manufacture of 2G ethanol in large scale is not a consolidated process yet. Thus, a detailed economic analysis, based on consistent simulations of the process, is worthwhile. Moreover, both ethanol and electric energy markets have been extremely volatile in Brazil, which suggests that a flexible biorefinery, able to switch between 2G ethanol and electric energy production, could be an option to absorb fluctuations in relative prices. Simulations of three cases were run using the software EMSO: production of 1G ethanol + electric energy, of 1G + 2G ethanol and a flexible biorefinery. Bagasse for 2G ethanol was pretreated with a weak acid solution, followed by enzymatic hydrolysis, while 50% of sugarcane trash (mostly leaves) was used as surplus fuel. Results With maximum diversion of bagasse to 2G ethanol (74% of the total), an increase of 25.8% in ethanol production (reaching 115.2 L/tonne of sugarcane) was achieved. An increase of 21.1% in the current ethanol price would be enough to make all three biorefineries economically viable (11.5% for the 1G + 2G dedicated biorefinery). For 2012 prices, the flexible biorefinery presented a lower Internal Rate of Return (IRR) than the 1G + 2G dedicated biorefinery. The impact of electric energy prices (auction and spot market) and of enzyme costs on the IRR was not as significant as it would be expected. Conclusions For current market prices in Brazil, not even production of 1G bioethanol is economically feasible. However, the 1G + 2G dedicated biorefinery is closer to feasibility than the conventional 1G + electric energy industrial plant. Besides, the IRR of the 1G + 2G biorefinery is more sensitive with respect to the price of ethanol, and an increase of 11.5% in this value would be enough to achieve feasibility. The ability of the flexible biorefinery to take advantage of seasonal fluctuations does not make up for its higher investment cost, in the present scenario. PMID:24088415

Industrial fuel ethanol yeasts contain adaptive copy number changes in genes involved in vitamin B1 and B6 biosynthesis.

PubMed

Stambuk, Boris U; Dunn, Barbara; Alves, Sergio L; Duval, Eduarda H; Sherlock, Gavin

2009-12-01

Fuel ethanol is now a global energy commodity that is competitive with gasoline. Using microarray-based comparative genome hybridization (aCGH), we have determined gene copy number variations (CNVs) common to five industrially important fuel ethanol Saccharomyces cerevisiae strains responsible for the production of billions of gallons of fuel ethanol per year from sugarcane. These strains have significant amplifications of the telomeric SNO and SNZ genes, which are involved in the biosynthesis of vitamins B6 (pyridoxine) and B1 (thiamin). We show that increased copy number of these genes confers the ability to grow more efficiently under the repressing effects of thiamin, especially in medium lacking pyridoxine and with high sugar concentrations. These genetic changes have likely been adaptive and selected for in the industrial environment, and may be required for the efficient utilization of biomass-derived sugars from other renewable feedstocks.

Industrial fuel ethanol yeasts contain adaptive copy number changes in genes involved in vitamin B1 and B6 biosynthesis

PubMed Central

Stambuk, Boris U.; Dunn, Barbara; Alves, Sergio L.; Duval, Eduarda H.; Sherlock, Gavin

2009-01-01

Fuel ethanol is now a global energy commodity that is competitive with gasoline. Using microarray-based comparative genome hybridization (aCGH), we have determined gene copy number variations (CNVs) common to five industrially important fuel ethanol Saccharomyces cerevisiae strains responsible for the production of billions of gallons of fuel ethanol per year from sugarcane. These strains have significant amplifications of the telomeric SNO and SNZ genes, which are involved in the biosynthesis of vitamins B6 (pyridoxine) and B1 (thiamin). We show that increased copy number of these genes confers the ability to grow more efficiently under the repressing effects of thiamin, especially in medium lacking pyridoxine and with high sugar concentrations. These genetic changes have likely been adaptive and selected for in the industrial environment, and may be required for the efficient utilization of biomass-derived sugars from other renewable feedstocks. PMID:19897511

Improvement of ethanol productivity and energy efficiency by degradation of inhibitors using recombinant Zymomonas mobilis (pHW20a-fdh).

PubMed

Dong, Hong-Wei; Fan, Li-Qiang; Luo, Zichen; Zhong, Jian-Jiang; Ryu, Dewey D Y; Bao, Jie

2013-09-01

Toxic compounds, such as formic acid, furfural, and hydroxymethylfurfural (HMF) generated during pretreatment of corn stover (CS) at high temperature and low pH, inhibit growth of Zymomonas mobilis and lower the conversion efficiency of CS to biofuel and other products. The inhibition of toxic compounds is considered as one of the major technical barriers in the lignocellulose bioconversion. In order to detoxify and/or degrade these toxic compounds by the model ethanologenic strain Z. mobilis itself in situ the fermentation medium, we constructed a recombinant Z. mobilis ZM4 (pHW20a-fdh) strain that is capable of degrading toxic inhibitor, formate. This is accomplished by cloning heterologous formate dehydrogenase gene (fdh) from Saccharomyces cerevisiae and by coupling this reaction of NADH regeneration reaction system with furfural and HMF degradation in the recombinant Z. mobilis strain. The NADH regeneration reaction also improved both the energy efficiency and cell physiological activity of the recombinant organism, which were definitely confirmed by the improved cell growth, ethanol yield, and ethanol productivity during fermentation with CS hydrolysate. Copyright © 2013 Wiley Periodicals, Inc.

Environmental and financial implications of ethanol as a bioethylene feedstock versus as a transportation fuel

NASA Astrophysics Data System (ADS)

McKechnie, Jon; Pourbafrani, Mohammad; Saville, Bradley A.; MacLean, Heather L.

2015-12-01

Bulk chemicals production from biomass may compete with biofuels for low-cost and sustainable biomass sources. Understanding how alternative uses of biomass compare in terms of financial and environmental parameters is therefore necessary to help ensure that efficient uses of resources are encouraged by policy and undertaken by industry. In this paper, we compare the environmental and financial performance of using ethanol as a feedstock for bioethylene production or as a transport fuel in the US life cycle-based models are developed to isolate the relative impacts of these two ethanol uses and generate results that are applicable irrespective of ethanol production pathway. Ethanol use as a feedstock for bioethylene production or as a transport fuel leads to comparable greenhouse gas (GHG) emissions and fossil energy consumption reductions relative to their counterparts produced from fossil sources. By displacing gasoline use in vehicles, use of ethanol as a transport fuel is six times more effective in reducing petroleum energy use on a life cycle basis. In contrast, bioethylene predominately avoids consumption of natural gas. Considering 2013 US ethanol and ethylene market prices, our analysis shows that bioethylene is financially viable only if significant price premiums are realized over conventional ethylene, from 35% to 65% depending on the scale of bioethylene production considered (80 000 t yr-1 to 240 000 t yr-1). Ethanol use as a transportation fuel is therefore the preferred pathway considering financial, GHG emissions, and petroleum energy use metrics, although bioethylene production could have strategic value if demand-side limitations of ethanol transport fuel markets are reached.

Improving Biofuels Recovery Processes for Energy Efficiency and Sustainability

EPA Science Inventory

Biofuels are made from living or recently living organisms. For example, ethanol can be made from fermented plant materials. Biofuels have a number of important benefits when compared to fossil fuels. Biofuels are produced from renewable energy sources such as agricultural resou...

Carboxylate platform: the MixAlco process part 1: comparison of three biomass conversion platforms.

PubMed

Holtzapple, Mark T; Granda, Cesar B

2009-05-01

To convert biomass to liquid fuels, three platforms are compared: thermochemical, sugar, and carboxylate. To create a common basis, each platform is fed "ideal biomass," which contains polysaccharides (68.3%) and lignin (31.7%). This ratio is typical of hardwood biomass and was selected so that when gasified and converted to hydrogen, the lignin has sufficient energy to produce ethanol from the carboxylic acids produced by the carboxylate platform. Using balanced chemical reactions, the theoretical yield and energy efficiency were determined for each platform. For all platforms, the ethanol yield can be increased by 71% to 107% by supplying external hydrogen produced from other sources (e.g., solar, wind, nuclear, fossil fuels). The alcohols can be converted to alkanes with a modest loss of energy efficiency (3 to 5 percentage points). Of the three platforms considered, the carboxylate platform has demonstrated the highest product yields.

Single temperature liquefaction process at different operating pHs to improve ethanol production from Indian rice and corn feedstock.

PubMed

Gohel, V; Ranganathan, K; Duan, G

2017-04-21

Conventional grain ethanol manufacturing is a high-temperature energy-intensive process comprising of multiple-unit operations when combined with lower ethanol recovery results in higher production cost. In liquefaction, jet cooking accounts for significant energy cost, while strong acid or base used for pH adjustment presents a safety hazard. A need is felt for sustainable ethanol manufacturing process that is less hazardous, consumes lower energy, and operates in a low pH range of 4.50-5.50. A single temperature liquefaction (STL) process that could efficiently operate at lower liquefaction temperature over a pH range of 4.50-5.50 was developed using rice and corn feedstock. Ethanol recovery witnessed at pH 4.5, 5.0, and 5.5 are 481.2 ± 1.5, 492.4 ± 1.5, and 493.6 ± 1.5 L MT -1 rice, respectively. Similarly, ethanol recovery witnessed at pH 4.5, 5.0, and 5.5 are 404.6 ± 1.3, 413.9 ± 0.8, and 412.4 ± 1.8 L MT -1 corn, respectively. The improvement in ethanol recovery is attributed to higher starch conversion by alpha-amylase even at pH as low as 4.50. Thus, the STL process operated at pH lower than 5.20 is poised to enhance sustainability by offering dual advantage of energy as well as chemical saving.

Woody biomass pretreatment for cellulosic ethanol production : technology and energy consumption evaluation

Treesearch

Junyong Zhu; X.J. Pan

2010-01-01

This review presents a comprehensive discussion of the key technical issues in woody biomass pretreatment: barriers to efficient cellulose saccharification, pretreatment energy consumption, in particular energy consumed for wood-size reduction, and criteria to evaluate the performance of a pretreatment. A post-chemical pretreatment size-reduction approach is proposed...

Performance of biofuel processes utilising separate lignin and carbohydrate processing.

PubMed

Melin, Kristian; Kohl, Thomas; Koskinen, Jukka; Hurme, Markku

2015-09-01

Novel biofuel pathways with increased product yields are evaluated against conventional lignocellulosic biofuel production processes: methanol or methane production via gasification and ethanol production via steam-explosion pre-treatment. The novel processes studied are ethanol production combined with methanol production by gasification, hydrocarbon fuel production with additional hydrogen produced from lignin residue gasification, methanol or methane synthesis using synthesis gas from lignin residue gasification and additional hydrogen obtained by aqueous phase reforming in synthesis gas production. The material and energy balances of the processes were calculated by Aspen flow sheet models and add on excel calculations applicable at the conceptual design stage to evaluate the pre-feasibility of the alternatives. The processes were compared using the following criteria: energy efficiency from biomass to products, primary energy efficiency, GHG reduction potential and economy (expressed as net present value: NPV). Several novel biorefinery concepts gave higher energy yields, GHG reduction potential and NPV. Copyright © 2015 Elsevier Ltd. All rights reserved.

Membrane processes for alcohol-water separation: Improving the energy efficiency of biofuel production

EPA Science Inventory

The economics and environmental impact of producing fuels and chemicals biologically can be a strong function of the efficiency with which the fermentation products are removed from the biological media. Due to growth inhibition by some fermentation products, including ethanol an...

Performance of dairy cows fed high levels of acetic acid or ethanol.

PubMed

Daniel, J L P; Amaral, R C; Sá Neto, A; Cabezas-Garcia, E H; Bispo, A W; Zopollatto, M; Cardoso, T L; Spoto, M H F; Santos, F A P; Nussio, L G

2013-01-01

Ethanol and acetic acid are common end products from silages. The main objective of this study was to determine whether high concentrations of ethanol or acetic acid in total mixed ration would affect performance in dairy cows. Thirty mid-lactation Holstein cows were grouped in 10 blocks and fed one of the following diets for 7 wk: (1) control (33% Bermuda hay + 67% concentrates), (2) ethanol [control diet + 5% ethanol, dry matter (DM) basis], or (3) acetic acid (control diet + 5% acetic acid, DM basis). Ethanol and acetic acid were diluted in water (1:2) and sprayed onto total mixed rations twice daily before feeding. An equal amount of water was mixed with the control ration. To adapt animals to these treatments, cows were fed only half of the treatment dose during the first week of study. Cows fed ethanol yielded more milk (37.9 kg/d) than those fed the control (35.8 kg/d) or acetic acid (35.3 kg/d) diets, mainly due to the higher DM intake (DMI; 23.7, 22.2, and 21.6 kg/d, respectively). The significant diet × week interaction for DMI, mainly during wk 2 and 3 (when acetic acid reached the full dose), was related to the decrease in DMI observed for the acetic acid treatment. There was a diet × week interaction in excretion of milk energy per DMI during wk 2 and 3, due to cows fed acetic acid sustained milk yield despite lower DMI. Energy efficiency was similar across diets. Blood metabolites (glucose, insulin, nonesterified fatty acids, ethanol, and γ-glutamyl transferase activity) and sensory characteristics of milk were not affected by these treatments. Animal performance suggested similar energy value for the diet containing ethanol compared with other diets. Rumen conversion of ethanol to acetate and a concomitant increase in methane production might be a plausible explanation for the deviation of the predicted energy value based on the heat of combustion. Therefore, the loss of volatile compounds during the drying process in the laboratory should be considered when calculating energy content of fermented feedstuffs. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Life-cycle energy and GHG emissions of forest biomass harvest and transport for biofuel production in Michigan

DOE PAGES

Zhang, Fengli; Johnson, Dana M.; Wang, Jinjiang

2015-04-01

High dependence on imported oil has increased U.S. strategic vulnerability and prompted more research in the area of renewable energy production. Ethanol production from renewable woody biomass, which could be a substitute for gasoline, has seen increased interest. This study analysed energy use and greenhouse gas emission impacts on the forest biomass supply chain activities within the State of Michigan. A life-cycle assessment of harvesting and transportation stages was completed utilizing peer-reviewed literature. Results for forest-delivered ethanol were compared with those for petroleum gasoline using data specific to the U.S. The analysis from a woody biomass feedstock supply perspective uncoveredmore » that ethanol production is more environmentally friendly (about 62% less greenhouse gas emissions) compared with petroleum based fossil fuel production. Sensitivity analysis was conducted with key inputs associated with harvesting and transportation operations. The results showed that research focused on improving biomass recovery efficiency and truck fuel economy further reduced GHG emissions and energy consumption.« less

Life-cycle energy and GHG emissions of forest biomass harvest and transport for biofuel production in Michigan

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

Zhang, Fengli; Johnson, Dana M.; Wang, Jinjiang

High dependence on imported oil has increased U.S. strategic vulnerability and prompted more research in the area of renewable energy production. Ethanol production from renewable woody biomass, which could be a substitute for gasoline, has seen increased interest. This study analysed energy use and greenhouse gas emission impacts on the forest biomass supply chain activities within the State of Michigan. A life-cycle assessment of harvesting and transportation stages was completed utilizing peer-reviewed literature. Results for forest-delivered ethanol were compared with those for petroleum gasoline using data specific to the U.S. The analysis from a woody biomass feedstock supply perspective uncoveredmore » that ethanol production is more environmentally friendly (about 62% less greenhouse gas emissions) compared with petroleum based fossil fuel production. Sensitivity analysis was conducted with key inputs associated with harvesting and transportation operations. The results showed that research focused on improving biomass recovery efficiency and truck fuel economy further reduced GHG emissions and energy consumption.« less

In vivo evolutionary engineering for ethanol-tolerance of Saccharomyces cerevisiae haploid cells triggers diploidization.

PubMed

Turanlı-Yıldız, Burcu; Benbadis, Laurent; Alkım, Ceren; Sezgin, Tuğba; Akşit, Arman; Gökçe, Abdülmecit; Öztürk, Yavuz; Baykal, Ahmet Tarık; Çakar, Zeynep Petek; François, Jean M

2017-09-01

Microbial ethanol production is an important alternative energy resource to replace fossil fuels, but at high level, this product is highly toxic, which hampers its efficient production. Towards increasing ethanol-tolerance of Saccharomyces cerevisiae, the so far best industrial ethanol-producer, we evaluated an in vivo evolutionary engineering strategy based on batch selection under both constant (5%, v v -1 ) and gradually increasing (5-11.4%, v v -1 ) ethanol concentrations. Selection under increasing ethanol levels yielded evolved clones that could tolerate up to 12% (v v -1 ) ethanol and had cross-resistance to other stresses. Quite surprisingly, diploidization of the yeast population took place already at 7% (v v -1 ) ethanol level during evolutionary engineering, and this event was abolished by the loss of MKT1, a gene previously identified as being implicated in ethanol tolerance (Swinnen et al., Genome Res., 22, 975-984, 2012). Transcriptomic analysis confirmed diploidization of the evolved clones with strong down-regulation in mating process, and in several haploid-specific genes. We selected two clones exhibiting the highest viability on 12% ethanol, and found productivity and titer of ethanol significantly higher than those of the reference strain under aerated fed-batch cultivation conditions. This higher fermentation performance could be related with a higher abundance of glycolytic and ribosomal proteins and with a relatively lower respiratory capacity of the evolved strain, as revealed by a comparative transcriptomic and proteomic analysis between the evolved and the reference strains. Altogether, these results emphasize the efficiency of the in vivo evolutionary engineering strategy for improving ethanol tolerance, and the link between ethanol tolerance and diploidization. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Techno-economic analysis and climate change impacts of sugarcane biorefineries considering different time horizons.

PubMed

Junqueira, Tassia L; Chagas, Mateus F; Gouveia, Vera L R; Rezende, Mylene C A F; Watanabe, Marcos D B; Jesus, Charles D F; Cavalett, Otavio; Milanez, Artur Y; Bonomi, Antonio

2017-01-01

Ethanol production from lignocellulosic feedstocks (also known as 2nd generation or 2G ethanol process) presents a great potential for reducing both ethanol production costs and climate change impacts since agricultural residues and dedicated energy crops are used as feedstock. This study aimed at the quantification of the economic and environmental impacts considering the current and future scenarios of sugarcane biorefineries taking into account not only the improvements of the industrial process but also of biomass production systems. Technology assumptions and scenarios setup were supported by main companies and stakeholders, involved in the lignocellulosic ethanol production chain from Brazil and abroad. For instance, scenarios considered higher efficiencies and lower residence times for pretreatment, enzymatic hydrolysis, and fermentation (including pentoses fermentation); higher sugarcane yields; and introduction of energy cane (a high fiber variety of cane). Ethanol production costs were estimated for different time horizons. In the short term, 2G ethanol presents higher costs compared to 1st generation (1G) ethanol. However, in the long term, 2G ethanol is more competitive, presenting remarkable lower production cost than 1G ethanol, even considering some uncertainties regarding technology and market aspects. In addition, environmental assessment showed that both 1G (in the medium and long term) and 2G ethanol can reduce climate change impacts by more than 80% when compared to gasoline. This work showed the great potential of 2G ethanol production in terms of economic and environmental aspects. These results can support new research programs and public policies designed to stimulate both production and consumption of 2G ethanol in Brazil, accelerating the path along the learning curve. Some examples of mechanisms include: incentives to the establishment of local equipment and enzyme suppliers; and specific funding programs for the development and use of energy cane.

Hydrogen Generation by Koh-Ethanol Plasma Electrolysis Using Double Compartement Reactor

NASA Astrophysics Data System (ADS)

Saksono, Nelson; Sasiang, Johannes; Dewi Rosalina, Chandra; Budikania, Trisutanti

2018-03-01

This study has successfully investigated the generation of hydrogen using double compartment reactor with plasma electrolysis process. Double compartment reactor is designed to achieve high discharged voltage, high concentration, and also reduce the energy consumption. The experimental results showed the use of double compartment reactor increased the productivity ratio 90 times higher compared to Faraday electrolysis process. The highest hydrogen production obtained is 26.50 mmol/min while the energy consumption can reach up 1.71 kJ/mmol H2 at 0.01 M KOH solution. It was shown that KOH concentration, addition of ethanol, cathode depth, and temperature have important effects on hydrogen production, energy consumption, and process efficiency.

A novel wild-type Saccharomyces cerevisiae strain TSH1 in scaling-up of solid-state fermentation of ethanol from sweet sorghum stalks.

PubMed

Du, Ran; Yan, Jianbin; Feng, Quanzhou; Li, Peipei; Zhang, Lei; Chang, Sandra; Li, Shizhong

2014-01-01

The rising demand for bioethanol, the most common alternative to petroleum-derived fuel used worldwide, has encouraged a feedstock shift to non-food crops to reduce the competition for resources between food and energy production. Sweet sorghum has become one of the most promising non-food energy crops because of its high output and strong adaptive ability. However, the means by which sweet sorghum stalks can be cost-effectively utilized for ethanol fermentation in large-scale industrial production and commercialization remains unclear. In this study, we identified a novel Saccharomyces cerevisiae strain, TSH1, from the soil in which sweet sorghum stalks were stored. This strain exhibited excellent ethanol fermentative capacity and ability to withstand stressful solid-state fermentation conditions. Furthermore, we gradually scaled up from a 500-mL flask to a 127-m3 rotary-drum fermenter and eventually constructed a 550-m3 rotary-drum fermentation system to establish an efficient industrial fermentation platform based on TSH1. The batch fermentations were completed in less than 20 hours, with up to 96 tons of crushed sweet sorghum stalks in the 550-m3 fermenter reaching 88% of relative theoretical ethanol yield (RTEY). These results collectively demonstrate that ethanol solid-state fermentation technology can be a highly efficient and low-cost solution for utilizing sweet sorghum, providing a feasible and economical means of developing non-food bioethanol.

A Novel Wild-Type Saccharomyces cerevisiae Strain TSH1 in Scaling-Up of Solid-State Fermentation of Ethanol from Sweet Sorghum Stalks

PubMed Central

Feng, Quanzhou; Li, Peipei; Zhang, Lei; Chang, Sandra; Li, Shizhong

2014-01-01

The rising demand for bioethanol, the most common alternative to petroleum-derived fuel used worldwide, has encouraged a feedstock shift to non-food crops to reduce the competition for resources between food and energy production. Sweet sorghum has become one of the most promising non-food energy crops because of its high output and strong adaptive ability. However, the means by which sweet sorghum stalks can be cost-effectively utilized for ethanol fermentation in large-scale industrial production and commercialization remains unclear. In this study, we identified a novel Saccharomyces cerevisiae strain, TSH1, from the soil in which sweet sorghum stalks were stored. This strain exhibited excellent ethanol fermentative capacity and ability to withstand stressful solid-state fermentation conditions. Furthermore, we gradually scaled up from a 500-mL flask to a 127-m3 rotary-drum fermenter and eventually constructed a 550-m3 rotary-drum fermentation system to establish an efficient industrial fermentation platform based on TSH1. The batch fermentations were completed in less than 20 hours, with up to 96 tons of crushed sweet sorghum stalks in the 550-m3 fermenter reaching 88% of relative theoretical ethanol yield (RTEY). These results collectively demonstrate that ethanol solid-state fermentation technology can be a highly efficient and low-cost solution for utilizing sweet sorghum, providing a feasible and economical means of developing non-food bioethanol. PMID:24736641

Fuel Cell Power Plants Renewable and Waste Fuels

DTIC Science & Technology

2011-01-13

of FuelCell Energy, Inc. Fuels Resources for DFC • Natural Gas and LNG • Propane • Biogas (by Anaerobicnaerobic Digestion) - Municipal Waste...FUEL RESOURCES z NATURAL GAS z PROPANE z DFC H2 (50-60%) z ETHANOL zWASTE METHANE z BIOGAS z COAL GAS Diversity of Fuels plus High Efficiency...trademarks (®) of FuelCell Energy, Inc. DFC Advantages for Biogas • More power for given amount of biogas : Higher efficiency than

Design of an artificial photosynthetic system for production of alcohols in high concentration from CO 2

DOE PAGES

Singh, Meenesh R.; Bell, Alexis T.

2015-11-06

Artificial photosynthesis of liquid fuels is a potential source for clean energy. Alcohols are particularly attractive products because of their high energy density and market value per amount of energy input. The major challenges in photo/electrochemical synthesis of alcohols from sunlight, water and CO 2 are low product selectivity, high membrane fuel-crossover losses, and high cost of product separation from the electrolyte. Here we propose an artificial photosynthesis scheme for direct synthesis and separation to almost pure ethanol with minimum product crossover using saturated salt electrolytes. The ethanol produced in the saturated salt electrolytes can be readily phase separated intomore » a microemulsion, which can be collected as pure products in a liquid–liquid extractor. A novel design of an integrated artificial photosynthetic system is proposed that continuously produces >90 wt% pure ethanol using a polycrystalline copper cathode at a current density of 0.85 mA cm -2. The annual production rate of >90 wt% ethanol using such a photosynthesis system operating at 10 mA cm -2 (12% solar-to-fuel (STF) efficiency) can be 15.27 million gallons per year per square kilometer, which corresponds to 7% of the industrial ethanol production capacity of California.« less

Highly Ordered Periodic Au/TiO₂ Hetero-Nanostructures for Plasmon-Induced Enhancement of the Activity and Stability for Ethanol Electro-oxidation.

PubMed

Jin, Zhao; Wang, Qiyu; Zheng, Weitao; Cui, Xiaoqiang

2016-03-02

The catalytic electro-oxidation of ethanol is the essential technique for direct alcohol fuel cells (DAFCs) in the area of alternative energy for the ability of converting the chemical energy of alcohol into the electric energy directly. Developing highly efficient and stable electrode materials with antipoisoning ability for ethanol electro-oxidation remains a challenge. A highly ordered periodic Au-nanoparticle (NP)-decorated bilayer TiO2 nanotube (BTNT) heteronanostructure was fabricated by a two-step anodic oxidation of Ti foil and the subsequent photoreduction of HAuCl4. The plasmon-induced charge separation on the heterointerface of Au/TiO2 electrode enhances the electrocatalytic activity and stability for the ethanol oxidation under visible light irradiation. The highly ordered periodic heterostructure on the electrode surface enhanced the light harvesting and led to the greater performance of ethanol electro-oxidation under irradiation compared with the ordinary Au NPs-decorated monolayer TiO2 nanotube (MTNT). This novel Au/TiO2 electrode also performed a self-cleaning property under visible light attributed to the enhanced electro-oxidation of the adsorbed intermediates. This light-driven enhancement of the electrochemical performances provides a development strategy for the design and construction of DAFCs.

Design of an artificial photosynthetic system for production of alcohols in high concentration from CO 2

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

Singh, Meenesh R.; Bell, Alexis T.

Artificial photosynthesis of liquid fuels is a potential source for clean energy. Alcohols are particularly attractive products because of their high energy density and market value per amount of energy input. The major challenges in photo/electrochemical synthesis of alcohols from sunlight, water and CO 2 are low product selectivity, high membrane fuel-crossover losses, and high cost of product separation from the electrolyte. Here we propose an artificial photosynthesis scheme for direct synthesis and separation to almost pure ethanol with minimum product crossover using saturated salt electrolytes. The ethanol produced in the saturated salt electrolytes can be readily phase separated intomore » a microemulsion, which can be collected as pure products in a liquid–liquid extractor. A novel design of an integrated artificial photosynthetic system is proposed that continuously produces >90 wt% pure ethanol using a polycrystalline copper cathode at a current density of 0.85 mA cm -2. The annual production rate of >90 wt% ethanol using such a photosynthesis system operating at 10 mA cm -2 (12% solar-to-fuel (STF) efficiency) can be 15.27 million gallons per year per square kilometer, which corresponds to 7% of the industrial ethanol production capacity of California.« less

Application of microbial electrolysis cells to treat spent yeast from an alcoholic fermentation.

PubMed

Sosa-Hernández, Ornella; Popat, Sudeep C; Parameswaran, Prathap; Alemán-Nava, Gibrán Sidney; Torres, César I; Buitrón, Germán; Parra-Saldívar, Roberto

2016-01-01

Spent yeast (SY), a major challenge for the brewing industry, was treated using a microbial electrolysis cell to recover energy. Concentrations of SY from bench alcoholic fermentation and ethanol were tested, ranging from 750 to 1500mgCOD/L and 0 to 2400mgCOD/L respectively. COD removal efficiency (RE), coulombic efficiency (CE), coulombic recovery (CR), hydrogen production and current density were evaluated. The best treatment condition was 750mgCOD/LSY+1200mgCOD/L ethanol giving higher COD RE, CE, CR (90±1%, 90±2% and 81±1% respectively), as compared with 1500mgCOD/LSY (76±2%, 63±7% and 48±4% respectively); ethanol addition was significantly favorable (p value=0.011), possibly due to electron availability and SY autolysis. 1500mgCOD/LSY+1200mgCOD/L ethanol achieved higher current density (222.0±31.3A/m(3)) and hydrogen production (2.18±0.66 [Formula: see text] ) but with lower efficiencies (87±2% COD RE, 71.0±.4% CE). Future work should focus on electron sinks, acclimation and optimizing SY breakdown. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Impact of pretreatment and downstream processing technologies on economics and energy in cellulosic ethanol production.

PubMed

Kumar, Deepak; Murthy, Ganti S

2011-09-05

While advantages of biofuel have been widely reported, studies also highlight the challenges in large scale production of biofuel. Cost of ethanol and process energy use in cellulosic ethanol plants are dependent on technologies used for conversion of feedstock. Process modeling can aid in identifying techno-economic bottlenecks in a production process. A comprehensive techno-economic analysis was performed for conversion of cellulosic feedstock to ethanol using some of the common pretreatment technologies: dilute acid, dilute alkali, hot water and steam explosion. Detailed process models incorporating feedstock handling, pretreatment, simultaneous saccharification and co-fermentation, ethanol recovery and downstream processing were developed using SuperPro Designer. Tall Fescue (Festuca arundinacea Schreb) was used as a model feedstock. Projected ethanol yields were 252.62, 255.80, 255.27 and 230.23 L/dry metric ton biomass for conversion process using dilute acid, dilute alkali, hot water and steam explosion pretreatment technologies respectively. Price of feedstock and cellulose enzymes were assumed as $50/metric ton and 0.517/kg broth (10% protein in broth, 600 FPU/g protein) respectively. Capital cost of ethanol plants processing 250,000 metric tons of feedstock/year was $1.92, $1.73, $1.72 and $1.70/L ethanol for process using dilute acid, dilute alkali, hot water and steam explosion pretreatment respectively. Ethanol production cost of $0.83, $0.88, $0.81 and $0.85/L ethanol was estimated for production process using dilute acid, dilute alkali, hot water and steam explosion pretreatment respectively. Water use in the production process using dilute acid, dilute alkali, hot water and steam explosion pretreatment was estimated 5.96, 6.07, 5.84 and 4.36 kg/L ethanol respectively. Ethanol price and energy use were highly dependent on process conditions used in the ethanol production plant. Potential for significant ethanol cost reductions exist in increasing pentose fermentation efficiency and reducing biomass and enzyme costs. The results demonstrated the importance of addressing the tradeoffs in capital costs, pretreatment and downstream processing technologies.

Impact of pretreatment and downstream processing technologies on economics and energy in cellulosic ethanol production

PubMed Central

2011-01-01

Background While advantages of biofuel have been widely reported, studies also highlight the challenges in large scale production of biofuel. Cost of ethanol and process energy use in cellulosic ethanol plants are dependent on technologies used for conversion of feedstock. Process modeling can aid in identifying techno-economic bottlenecks in a production process. A comprehensive techno-economic analysis was performed for conversion of cellulosic feedstock to ethanol using some of the common pretreatment technologies: dilute acid, dilute alkali, hot water and steam explosion. Detailed process models incorporating feedstock handling, pretreatment, simultaneous saccharification and co-fermentation, ethanol recovery and downstream processing were developed using SuperPro Designer. Tall Fescue (Festuca arundinacea Schreb) was used as a model feedstock. Results Projected ethanol yields were 252.62, 255.80, 255.27 and 230.23 L/dry metric ton biomass for conversion process using dilute acid, dilute alkali, hot water and steam explosion pretreatment technologies respectively. Price of feedstock and cellulose enzymes were assumed as $50/metric ton and 0.517/kg broth (10% protein in broth, 600 FPU/g protein) respectively. Capital cost of ethanol plants processing 250,000 metric tons of feedstock/year was $1.92, $1.73, $1.72 and $1.70/L ethanol for process using dilute acid, dilute alkali, hot water and steam explosion pretreatment respectively. Ethanol production cost of $0.83, $0.88, $0.81 and $0.85/L ethanol was estimated for production process using dilute acid, dilute alkali, hot water and steam explosion pretreatment respectively. Water use in the production process using dilute acid, dilute alkali, hot water and steam explosion pretreatment was estimated 5.96, 6.07, 5.84 and 4.36 kg/L ethanol respectively. Conclusions Ethanol price and energy use were highly dependent on process conditions used in the ethanol production plant. Potential for significant ethanol cost reductions exist in increasing pentose fermentation efficiency and reducing biomass and enzyme costs. The results demonstrated the importance of addressing the tradeoffs in capital costs, pretreatment and downstream processing technologies. PMID:21892958

Anaerobic digestion of thin stillage for energy recovery and water reuse in corn-ethanol plants.

PubMed

Alkan-Ozkaynak, A; Karthikeyan, K G

2011-11-01

Recycling of anaerobically-digested thin stillage within a corn-ethanol plant may result in the accumulation of nutrients of environmental concern in animal feed coproducts and inhibitory organic materials in the fermentation tank. Our focus is on anaerobic digestion of treated (centrifugation and lime addition) thin stillage. Suitability of digestate from anaerobic treatment for reuse as process water was also investigated. Experiments conducted at various inoculum-to-substrate ratios (ISRs) revealed that alkalinity is a critical parameter limiting digestibility of thin stillage. An ISR level of 2 appeared optimal based on high biogas production level (763 mL biogas/g volatile solids added) and organic matter removal (80.6% COD removal). The digester supernatant at this ISR level was found to contain both organic and inorganic constituents at levels that would cause no inhibition to ethanol fermentation. Anaerobic digestion of treated-thin stillage can be expected to improve the water and energy efficiencies of dry grind corn-ethanol plants. Copyright © 2011 Elsevier Ltd. All rights reserved.

Consolidated bioprocessing strategy for ethanol production from Jerusalem artichoke tubers by Kluyveromyces marxianus under high gravity conditions.

PubMed

Yuan, W J; Chang, B L; Ren, J G; Liu, J P; Bai, F W; Li, Y Y

2012-01-01

Developing an innovative process for ethanol fermentation from Jerusalem artichoke tubers under very high gravity (VHG) conditions. A consolidated bioprocessing (CBP) strategy that integrated inulinase production, saccharification of inulin contained in Jerusalem artichoke tubers and ethanol production from sugars released from inulin by the enzyme was developed with the inulinase-producing yeast Kluyveromyces marxianus Y179 and fed-batch operation. The impact of inoculum age, aeration, the supplementation of pectinase and nutrients on the ethanol fermentation performance of the CBP system was studied. Although inulinase activities increased with the extension of the seed incubation time, its contribution to ethanol production was negligible because vigorously growing yeast cells harvested earlier carried out ethanol fermentation more efficiently. Thus, the overnight incubation that has been practised in ethanol production from starch-based feedstocks is recommended. Aeration facilitated the fermentation process, but compromised ethanol yield because of the negative Crabtree effect of the species, and increases the risk of contamination under industrial conditions. Therefore, nonaeration conditions are preferred for the CBP system. Pectinase supplementation reduced viscosity of the fermentation broth and improved ethanol production performance, particularly under high gravity conditions, but the enzyme cost should be carefully balanced. Medium optimization was performed, and ethanol concentration as high as 94·2 g l(-1) was achieved when 0·15 g l(-1) K(2) HPO(4) was supplemented, which presents a significant progress in ethanol production from Jerusalem artichoke tubers. A CBP system using K. marxianus is suitable for efficient ethanol production from Jerusalem artichoke tubers under VHG conditions. Jerusalem artichoke tubers are an alternative to grain-based feedstocks for ethanol production. The high ethanol concentration achieved using K. marxianus with the CBP system not only saves energy consumption for ethanol distillation, but also significantly reduces the amount of waste distillage discharged from the distillation system. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

Assessment of different pretreatment technologies for efficient bioconversion of lignocellulose to ethanol.

PubMed

Singh, Jitendra K; Vyas, Preeti; Dubey, Anamika; Upadhyaya, Chandrama Prakash; Kothari, Richa; Tyagi, Vineet Veer; Kumar, Ashwani

2018-06-01

The future supply of energy to meet growing energy demand of rapidly exapanding populations is based on wide energy resources, particularly the renewable ones. Among all resources, lignocellulosic biomasses such as agriculture, forest, and agro-industrial residues are the most abundant and easily available bioresource for biorefineries to provide fuels, chemicals, and materials. However, pretreatment of biomass is required to overcome the physical and chemical barriers that exist in the lignin-carbohydrate composite and pretreatment facilitate the entry of biocatalysts for the conversion of biomass into fermentable sugars and other by-products. Therefore, pretreatment of the biomass is necessary prerequisite for efficient hydrolysis of lignocelluloses into different type of fermentable sugars. The physiochemical, biochemical and biological pretreatment methods are considered as most promising technologies for the biomass hydrolysis and are discussed in this review article. We also discussed the recent advancements and modern trends in pretreatment methods of lignocelluloses conversion into ethanol with special focus on fermentation methods.

Biofuels as an Alternative Energy Source for Aviation-A Survey

NASA Technical Reports Server (NTRS)

McDowellBomani, Bilal M.; Bulzan, Dan L.; Centeno-Gomez, Diana I.; Hendricks, Robert C.

2009-01-01

The use of biofuels has been gaining in popularity over the past few years because of their ability to reduce the dependence on fossil fuels. As a renewable energy source, biofuels can be a viable option for sustaining long-term energy needs if they are managed efficiently. We investigate past, present, and possible future biofuel alternatives currently being researched and applied around the world. More specifically, we investigate the use of ethanol, cellulosic ethanol, biodiesel (palm oil, algae, and halophytes), and synthetic fuel blends that can potentially be used as fuels for aviation and nonaerospace applications. We also investigate the processing of biomass via gasification, hydrolysis, and anaerobic digestion as a way to extract fuel oil from alternative biofuels sources.

Ultrasound enhanced glucose release from corn in ethanol plants.

PubMed

Khanal, Samir Kumar; Montalbo, Melissa; van Leeuwen, J; Srinivasan, Gowrishankar; Grewell, David

2007-12-01

This work evaluated the use of high power ultrasonic energy to treat corn slurry in dry corn milling ethanol plants to enhance liquefaction and saccharification for ethanol production. Corn slurry samples obtained before and after jet cooking were subjected to ultrasonic pretreatment for 20 and 40 s at amplitudes of vibration ranging from 180 to 299 microm(pp) (peak to peak amplitude in microm). The resulting samples were then exposed to enzymes (alpha-amylase and glucoamylase) to convert cornstarch into glucose. A comparison of scanning electron micrographs of raw and sonicated samples showed the development of micropores and the disruption of cell walls in corn mash. The corn particle size declined nearly 20-fold following ultrasonic treatment at high power settings. The glucose release rate from sonicated samples increased as much as threefold compared to the control group. The efficiency of ultrasound exceeded 100% in terms of energy gain from the sugar released over the ultrasonic energy supplied. Enzymatic activity was enhanced when the corn slurry was sonicated with simultaneous addition of enzymes. This finding suggests that the ultrasonic energy did not degrade or denature the enzymes during the pretreatment.

Laser ablation efficiency during the production of Ag nanoparticles in ethanol at a low pulse repetition rate (1-10 Hz)

NASA Astrophysics Data System (ADS)

Valverde-Alva, M. A.; García-Fernández, T.; Esparza-Alegría, E.; Villagrán-Muniz, M.; Sánchez-Aké, C.; Castañeda-Guzmán, R.; de la Mora, M. B.; Márquez-Herrera, C. E.; Sánchez Llamazares, J. L.

2016-10-01

We studied the effect of the repetition rate of laser pulses (RRLP) in the range from 1-10 Hz in the production of silver nanoparticles (Ag-NPs) by laser ablation in ethanol. Laser pulses with a duration of 7 ns, a wavelength of 1064 nm and an energy of 60 mJ were used to ablate a 99.99% pure silver target immersed in 10 ml of ethanol. Transmittance analysis and atomic absorption spectroscopy were used to study the silver concentration in the colloidal solutions. The ablation process was studied by measuring the transmission of the laser pulses through the colloid. It is shown that for a fixed number of laser pulses (NLP) the ablation efficiency, in terms of the ablated silver mass per laser pulse, increases with the RRLP. This result contradicts what had previously been established in the literature.

Assessing energy efficiencies and greenhouse gas emissions under bioethanol-oriented paddy rice production in northern Japan.

PubMed

Koga, Nobuhisa; Tajima, Ryosuke

2011-03-01

To establish energetically and environmentally viable paddy rice-based bioethanol production systems in northern Japan, it is important to implement appropriately selected agronomic practice options during the rice cultivation step. In this context, effects of rice variety (conventional vs. high-yielding) and rice straw management (return to vs. removal from the paddy field) on energy inputs from fuels and consumption of materials, greenhouse gas emissions (fuel and material consumption-derived CO(2) emissions as well as paddy soil CH(4) and N(2)O emissions) and ethanol yields were assessed. The estimated ethanol yield from the high-yielding rice variety, "Kita-aoba" was 2.94 kL ha(-1), a 32% increase from the conventional rice variety, "Kirara 397". Under conventional rice production in northern Japan (conventional rice variety and straw returned to the paddy), raising seedlings, mechanical field operations, transportation of harvested unhulled brown rice and consumption of materials (seeds, fertilizers, biocides and agricultural machinery) amounted to 28.5 GJ ha(-1) in energy inputs. The total energy input was increased by 14% by using the high-yielding variety and straw removal, owing to increased requirements for fuels in harvesting and transporting harvested rice as well as in collecting, loading and transporting rice straw. In terms of energy efficiency, the variation among rice variety and straw management scenarios regarding rice varieties and rice straw management was small (28.5-32.6 GJ ha(-1) or 10.1-14.0 MJ L(-1)). Meanwhile, CO(2)-equivalent greenhouse gas emissions varied considerably from scenario to scenario, as straw management had significant impacts on CH(4) emissions from paddy soils. When rice straw was incorporated into the soil, total CO(2)-equivalent greenhouse gas emissions for "Kirara 397" and "Kita-aoba" were 25.5 and 28.2 Mg CO(2) ha(-1), respectively; however, these emissions were reduced notably for the two varieties when rice straw was removed from the paddy fields in an effort to mitigate CH(4) emissions. Thus, rice straw removal avers itself a key practice with respect to lessening the impacts of greenhouse gas emissions in paddy rice-based ethanol production systems in northern Japan. More crucially, the rice straw removed is available for ethanol production and generation of heat energy with a biomass boiler, all elements required for biomass-to-ethanol transformation steps including saccharification, fermentation and distillation. This indicates opportunities for further improvement in energy efficiency and reductions in greenhouse gas emissions under whole rice plant-based bioethanol production systems. Copyright © 2010 Elsevier Ltd. All rights reserved.

No-Cook Process for Ethanol Production Using Indian Broken Rice and Pearl Millet

PubMed Central

Gohel, Vipul; Duan, Gang

2012-01-01

No-cook process using granular starch hydrolyzing enzyme (GSHE) was evaluated for Indian broken rice and pearl millet. One-factor-at-a-time optimization method was used in ethanol production to identify optimum concentration of GSHE, under yeast fermentation conditions using broken rice and pearl millet as fermentation feedstocks. An acid fungal protease at a concentration of 0.2 kg per metric ton of grain was used along with various dosages of GSHE under yeast fermentation conditions to degrade the grain proteins into free amino nitrogen for yeast growth. To measure the efficacy of GSHE to hydrolyze no-cook broken rice and pearl millet, the chemical composition, fermentation efficiency, and ethanol recovery were determined. In both feedstocks, fermentation efficiency and ethanol recovery obtained through single-step no-cook process were higher than conventional multistep high-temperature process, currently considered the ideal industrial process. Furthermore, the no-cook process can directly impact energy consumption through steam saving and reducing the water cooling capacity needs, compared to conventional high-temperature process. PMID:22518148

Western Kentucky University Research Foundation Biodiesel Project

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

Pan, Wei-Ping; Cao, Yan

2013-03-15

Petroleum-based liquid hydrocarbons is exclusively major energy source in the transportation sector. Thus, it is the major CO{sub 2} source which is the associated with greenhouse effect. In the United States alone, petroleum consumption in the transportation sector approaches 13.8 million barrels per day (Mbbl/d). It is corresponding to a release of 0.53 gigatons of carbon per year (GtC/yr), which accounts for approximate 7.6 % of the current global release of CO{sub 2} from all of the fossil fuel usage (7 GtC/yr). For the long term, the conventional petroleum production is predicted to peak in as little as the nextmore » 10 years to as high as the next 50 years. Negative environmental consequences, the frequently roaring petroleum prices, increasing petroleum utilization and concerns about competitive supplies of petroleum have driven dramatic interest in producing alternative transportation fuels, such as electricity-based, hydrogen-based and bio-based transportation alternative fuels. Use of either of electricity-based or hydrogen-based alternative energy in the transportation sector is currently laden with technical and economical challenges. The current energy density of commercial batteries is 175 Wh/kg of battery. At a storage pressure of 680 atm, the lower heating value (LHV) of H{sub 2} is 1.32 kWh/liter. In contrast, the corresponding energy density for gasoline can reach as high as 8.88 kWh/liter. Furthermore, the convenience of using a liquid hydrocarbon fuel through the existing infrastructures is a big deterrent to replacement by both batteries and hydrogen. Biomass-derived ethanol and bio-diesel (biofuels) can be two promising and predominant U.S. alternative transportation fuels. Both their energy densities and physical properties are comparable to their relatives of petroleum-based gasoline and diesel, however, biofuels are significantly environmental-benign. Ethanol can be made from the sugar-based or starch-based biomass materials, which is easily fermented to create ethanol. In the United States almost all starch ethanol is mainly manufactured from corn grains. The technology for manufacturing corn ethanol can be considered mature as of the late 1980s. In 2005, 14.3 % of the U.S. corn harvest was processed to produce 1.48 x10{sup 10} liters of ethanol, energetically equivalent to 1.72 % of U.S. gasoline usage. Soybean oil is extracted from 1.5 % of the U.S. soybean harvest to produce 2.56 x 10{sup 8} liters of bio-diesel, which was 0.09 % of U.S. diesel usage. However, reaching maximum rates of bio-fuel supply from corn and soybeans is unlikely because these crops are presently major contributors to human food supplies through livestock feed and direct consumption. Moreover, there currently arguments on that the conversion of many types of many natural landscapes to grow corn for feedstock is likely to create substantial carbon emissions that will exacerbate globe warming. On the other hand, there is a large underutilized resource of cellulose biomass from trees, grasses, and nonedible parts of crops that could serve as a feedstock. One of the potentially significant new bio-fuels is so called "cellulosic ethanol", which is dependent on break-down by microbes or enzymes. Because of technological limitations (the wider variety of molecular structures in cellulose and hemicellulose requires a wider variety of microorganisms to break them down) and other cost hurdles (such as lower kinetics), cellulosic ethanol can currently remain in lab scales. Considering farm yields, commodity and fuel prices, farm energy and agrichemical inputs, production plant efficiencies, byproduct production, greenhouse gas (GHG) emissions, and other environmental effects, a life-cycle evaluation of competitive indicated that corn ethanol yields 25 % more energy than the energy invested in its production, whereas soybean bio-diesel yields 93 % more. Relative to the fossil fuels they displace, greenhouse gas emissions are reduced 12 % by the production and combustion of ethanol and 41 % by bio-diesel. Bio-diesel also releases less air pollutants per net energy gain than ethanol. Bio-diesel has advantages over ethanol due to its lower agricultural inputs and more efficient conversion. Thus, to be a viable alternative, a bio-fuel firstly should be producible in large quantities without reducing food supplies. In this aspect, larger quantity supplies of cellulose biomass are likely viable alternatives. U. S. Congress has introduced an initiative and subsequently rolled into the basic energy package, which encourages the production of fuel from purely renewable resources, biomass. Secondly, a bio-fuel should also provide a net energy gain, have environmental benefits and be economically competitive. In this aspect, bio-diesel has advantages over ethanol. The commonwealth of Kentucky is fortunate to have a diverse and abundant supply of renewable energy resources. Both Kentucky Governor Beshear in the energy plan for Kentucky "Intelligent Energy Choices for Kentucky's Future", and Kentucky Renewable Energy Consortium, outlined strategies on developing energy in renewable, sustainable and efficient ways. Smart utilization of diversified renewable energy resources using advanced technologies developed by Kentucky public universities, and promotion of these technologies to the market place by collaboration between universities and private industry, are specially encouraged. Thus, the initially question answering Governor's strategic plan is if there is any economical way to make utilization of larger quantities of cellulose and hemicellulose for production of bio-fuels, especially bio-diesel. There are some possible options of commercially available technologies to convert cellulose based biomass energy to bio-fuels. Cellulose based biomass can be firstly gasified to obtain synthesis gas (a mixture of CO and H{sub 2}), which is followed up by being converted into liquid hydrocarbon fuels or oxygenate hydrocarbon fuel through Fischer-Tropsch (F-T) synthesis. Methanol production is regarded to be the most economic starting step in many-year practices of the development of F-T synthesis technology since only C{sub 1} synthesis through F-T process can potentially achieve 100% conversion efficiency. Mobil's F-T synthesis process is based on this understanding. Considering the economical advantages of bio-diesel production over ethanol and necessary supply of methanol during bio-diesel production, a new opportunity for bio-diesel production with total supplies of biomass-based raw materials through more economic reaction pathways is likely identified in this proposal. The bio-oil part of biomass can be transesterified under available methanol (or mixed alcohols), which can be synthesized in the most easy part of F-T synthesis process using synthesis gas from gasification of cellulose fractions of biomass. We propose a novel concept to make sense of bio-diesel production economically though a coupling reaction of bio-oil transesterification and methanol synthesis. It will overcome problems of current bio-diesel producing process based on separated handling of methanol and bio-oil.« less

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.

Effects of solution volume on hydrogen production by pulsed spark discharge in ethanol solution

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

Xin, Y. B.; Sun, B., E-mail: sunb88@dlmu.edu.cn; Zhu, X. M.

2016-07-15

Hydrogen production from ethanol solution (ethanol/water) by pulsed spark discharge was optimized by varying the volume of ethanol solution (liquid volume). Hydrogen yield was initially increased and then decreased with the increase in solution volume, which achieved 1.5 l/min with a solution volume of 500 ml. The characteristics of pulsed spark discharge were studied in this work; the results showed that the intensity of peak current, the rate of current rise, and energy efficiency of hydrogen production can be changed by varying the volume of ethanol solution. Meanwhile, the mechanism analysis of hydrogen production was accomplished by monitoring the process of hydrogenmore » production and the state of free radicals. The analysis showed that decreasing the retention time of gas production and properly increasing the volume of ethanol solution can enhance the hydrogen yield. Through this research, a high-yield and large-scale method of hydrogen production can be achieved, which is more suitable for industrial application.« less

High laser efficiency and photostability of pyrromethene dyes mediated by nonpolar solvent.

PubMed

Gupta, Monika; Kamble, Priyadarshini; Rath, M C; Naik, D B; Ray, Alok K

2015-08-10

Many pyrromethene (PM) dyes have been shown to outperform established rhodamine dyes in terms of laser efficiency in the green-yellow spectral region, but their rapid photochemical degradation in commonly used ethanol or methanol solvents continues to limit its use in high average power liquid dye lasers. A comparative study on narrowband laser efficiency and photostability of commercially available PM567 and PM597 dyes, using nonpolar n-heptane and 1,4-dioxane and polar ethanol solvents, was carried out by a constructed pulsed dye laser, pumped by the second harmonic (532 nm) radiation of a Q-switched Nd:YAG laser. Interestingly, both nonpolar solvents showed a significantly higher laser photostability (∼100 times) as well as peak efficiency (∼5%) of these PM dyes in comparison to ethanol. The different photostability of the PM dyes was rationalized by determining their triplet-state spectra and capability to generate reactive singlet oxygen (O₂1) by energy transfer to dissolved oxygen in these solvents using pulse radiolysis. Heptane is identified as a promising solvent for these PM dyes for use in high average power dye lasers, pumped by copper vapor lasers or diode-pumped solid-state green lasers.

Assessment of different pre-treatment methods for the removal of limonene in citrus waste and their effect on methane potential and methane production rate.

PubMed

Ruiz, Begoña; de Benito, Amparo; Rivera, José Daniel; Flotats, Xavier

2016-12-01

The objective of this study was to assess the limonene removal efficiency of three pre-treatment methods when applied to citrus waste and to evaluate their effects on the biochemical methane potential and the methane production rate using batch anaerobic tests. The methods tested were based on removal (biological pretreatment by fungi) or recovery (steam distillation and ethanol extraction) of limonene. All the treatments decreased the concentration of limonene in orange peel, with average efficiencies of 22%, 44% and 100% for the biological treatment, steam distillation and ethanol extraction, respectively. By-products from limonene biodegradation by fungi exhibited an inhibitory effect also, not making interesting the biological pretreatment. The methane potential and production rate of the treated orange peel increased significantly after applying the recovery strategies, which separated and recovered simultaneously other inhibitory components of the citrus essential oil. Apart from the high recovery efficiency of the ethanol extraction process, it presented a favourable energy balance. © The Author(s) 2016.

Dehydration of ethanol by facile synthesized glucose-based silica.

PubMed

Tang, Baokun; Bi, Wentao; Row, Kyung Ho

2013-02-01

Bioethanol is considered a potential liquid fuel that can be produced from biomass by fermentation and distillation. Although most of the water is removed by distillation, the purity of ethanol is limited to 95-96 % due to the formation of a low-boiling point, water-ethanol azeotrope. To improve the use of ethanol as a fuel, many methods, such as dehydration, have been proposed to avoid distillation and improve the energy efficiency of extraction. Glucose-based silica, as an adsorbent, was prepared using a simple method, and was proposed for the adsorption of water from water-ethanol mixtures. After adsorption using 0.4 g of adsorbent for 3 h, the initial water concentration of 20 % (water, v/v) was decreased to 10 % (water, v/v). For water concentrations less than 5 % (water, v/v), the adsorbent could concentrate ethanol to 99 % (ethanol, v/v). The Langmuir isotherms used to describe the adsorption of water on an adsorbent showed a correlation coefficient of 0.94. The separation factor of the adsorbent also decreased with decreasing concentration of water in solution.

Butanol production by fermentation: efficient bioreactors

USDA-ARS?s Scientific Manuscript database

Energy security, environmental concerns, and business opportunities in the emerging bio-economy have generated strong interest in the production of n-butanol by fermentation. Acetone butanol ethanol (ABE or solvent) batch fermentation process is product limiting because butanol even at low concentra...

Evaluation of the fermentation of high gravity thick sugar beet juice worts for efficient bioethanol production

PubMed Central

2013-01-01

Background Sugar beet and intermediates of sugar beet processing are considered to be very attractive feedstock for ethanol production due to their content of fermentable sugars. In particular, the processing of the intermediates into ethanol is considerably facilitated because it does not require pretreatment or enzymatic treatment in contrast to production from starch raw materials. Moreover, the advantage of thick juice is high solid substance and saccharose content which eliminates problems with the storability of this feedstock. Results The objective of this study were to investigate bioethanol production from thick juice worts and the effects of their concentration, the type of mineral supplement, as well as the dose of yeast inoculum on fermentation dynamics and ethanol yield. The obtained results show that to ensure efficient ethanolic fermentation of high gravity thick juice worts, one needs to use a yeast strain with high ethanol tolerance and a large amount of inoculum. The highest ethanol yield (94.9 ± 2.8% of the theoretical yield) and sugars intake of 96.5 ± 2.9% were obtained after the fermentation of wort with an extract content of 250 g/kg supplemented with diammonium hydrogen phosphate (0.3 g/L of wort) and inoculated with 2 g of Ethanol Red dry yeast per L of wort. An increase in extract content in the fermentation medium from 250 g/L to 280 g/kg resulted in decreased efficiency of the process. Also the distillates originating from worts with an extract content of 250 g/kg were characterized by lower acetaldehyde concentration than those obtained from worts with an extract content of 280 g/kg. Conclusions Under the favorable conditions determined in our experiments, 38.9 ± 1.2 L of 100% (v/v) ethyl alcohol can be produced from 100 kg of thick juice. The obtained results show that the selection of process conditions and the yeast for the fermentation of worts with a higher sugar content can improve the economic performance of the alcohol-distilling industry due to more efficient ethanol production, reduced consumption of cooling water, and energy for ethanol distillation, as well as a decreased volume of fermentation stillage. PMID:24206573

Evaluation of the fermentation of high gravity thick sugar beet juice worts for efficient bioethanol production.

PubMed

Dziugan, Piotr; Balcerek, Maria; Pielech-Przybylska, Katarzyna; Patelski, Piotr

2013-11-08

Sugar beet and intermediates of sugar beet processing are considered to be very attractive feedstock for ethanol production due to their content of fermentable sugars. In particular, the processing of the intermediates into ethanol is considerably facilitated because it does not require pretreatment or enzymatic treatment in contrast to production from starch raw materials. Moreover, the advantage of thick juice is high solid substance and saccharose content which eliminates problems with the storability of this feedstock. The objective of this study were to investigate bioethanol production from thick juice worts and the effects of their concentration, the type of mineral supplement, as well as the dose of yeast inoculum on fermentation dynamics and ethanol yield.The obtained results show that to ensure efficient ethanolic fermentation of high gravity thick juice worts, one needs to use a yeast strain with high ethanol tolerance and a large amount of inoculum. The highest ethanol yield (94.9 ± 2.8% of the theoretical yield) and sugars intake of 96.5 ± 2.9% were obtained after the fermentation of wort with an extract content of 250 g/kg supplemented with diammonium hydrogen phosphate (0.3 g/L of wort) and inoculated with 2 g of Ethanol Red dry yeast per L of wort. An increase in extract content in the fermentation medium from 250 g/L to 280 g/kg resulted in decreased efficiency of the process. Also the distillates originating from worts with an extract content of 250 g/kg were characterized by lower acetaldehyde concentration than those obtained from worts with an extract content of 280 g/kg. Under the favorable conditions determined in our experiments, 38.9 ± 1.2 L of 100% (v/v) ethyl alcohol can be produced from 100 kg of thick juice. The obtained results show that the selection of process conditions and the yeast for the fermentation of worts with a higher sugar content can improve the economic performance of the alcohol-distilling industry due to more efficient ethanol production, reduced consumption of cooling water, and energy for ethanol distillation, as well as a decreased volume of fermentation stillage.

Hybrid Automotive Engine Using Ethanol-Burning Miller Cycle

NASA Technical Reports Server (NTRS)

Weinstein, Leonard

2004-01-01

A proposed hybrid (internal-combustion/ electric) automotive engine system would include as its internal-combustion subsystem, a modified Miller-cycle engine with regenerative air preheating and with autoignition like that of a Diesel engine. The fuel would be ethanol and would be burned lean to ensure complete combustion. Although the proposed engine would have a relatively low power-to-weight ratio compared to most present engines, this would not be the problem encountered if this engine were used in a non-hybrid system since hybrid systems require significantly lower power and thus smaller engines than purely internal-combustion-engine-driven vehicles. The disadvantage would be offset by the advantages of high fuel efficiency, low emission of nitrogen oxides and particulate pollutants, and the fact that ethanol is a renewable fuel. The original Miller-cycle engine, named after its inventor, was patented in the 1940s and is the basis of engines used in some modern automobiles, but is not widely known. In somewhat oversimplified terms, the main difference between a Miller-cycle engine and a common (Otto-cycle) automobile engine is that the Miller-cycle engine has a longer expansion stroke while retaining the shorter compression stroke. This is accomplished by leaving the intake valve open for part of the compression stroke, whereas in the Otto cycle engine, the intake valve is kept closed during the entire compression stroke. This greater expansion ratio makes it possible to extract more energy from the combustion process without expending more energy for compression. The net result is greater efficiency. In the proposed engine, the regenerative preheating would be effected by running the intake air through a heat exchanger connected to the engine block. The regenerative preheating would offer two advantages: It would ensure reliable autoignition during operation at low ambient temperature and would help to cool the engine, thereby reducing the remainder of the power needed for cooling and thereby further contributing to efficiency. An electrical resistance air preheater might be needed to ensure autoignition at startup and during a short warmup period. Because of the autoignition, the engine could operate without either spark plugs or glow plugs. Ethanol burns relatively cleanly and has been used as a motor fuel since the invention of internal-combustion engines. However, the energy content of ethanol per unit weight of ethanol is less than that of Diesel fuel or gasoline, and ethanol has a higher heat of vaporization. Because the Miller cycle offers an efficiency close to that of the Diesel cycle, burning ethanol in a Miller-cycle engine gives about as much usable output energy per unit volume of fuel as does burning gasoline in a conventional gasoline automotive engine. Because of the combination of preheating, running lean, and the use of ethyl alcohol, the proposed engine would generate less power per unit volume than does a conventional automotive gasoline engine. Consequently, for a given power level, the main body of the proposed engine would be bulkier. However, because little or no exhaust cleanup would be needed, the increase in bulk of the engine could be partially offset by the decrease in bulk of the exhaust system. The regenerative preheating also greatly reduces the external engine cooling requirement, and would translate to reduced engine bulk. It may even be possible to accomplish the remaining cooling of the engine by use of air only, eliminating the bulk and power consumption of a water cooling system. The combination of a Miller-cycle engine with regenerative air preheating, ethyl alcohol fuel, and hybrid operation could result in an automotive engine system that satisfies the need for a low pollution, high efficiency, and simple engine with a totally renewable fuel.

Elucidating central metabolic redox obstacles hindering ethanol production in Clostridium thermocellum

DOE PAGES

Thompson, R. Adam; Layton, Donovan S.; Guss, Adam M.; ...

2015-10-21

Clostridium thermocellum is an anaerobic, Gram-positive, thermophilic bacterium that has generated great interest due to its ability to ferment lignocellulosic biomass to ethanol. However, ethanol production is low due to the complex and poorly understood branched metabolism of C. thermocellum, and in some cases overflow metabolism as well. In this work, we developed a predictive stoichiometric metabolic model for C. thermocellum which incorporates the current state of understanding, with particular attention to cofactor specificity in the atypical glycolytic enzymes and the complex energy, redox, and fermentative pathways with the goal of aiding metabolic engineering efforts. We validated the model smore » capability to encompass experimentally observed phenotypes for the parent strain and derived mutants designed for significant perturbation of redox and energy pathways. Metabolic flux distributions revealed significant alterations in key metabolic branch points (e.g., phosphoenol pyruvate, pyruvate, acetyl-CoA, and cofactor nodes) in engineered strains for channeling electron and carbon fluxes for enhanced ethanol synthesis, with the best performing strain doubling ethanol yield and titer compared to the parent strain. In silico predictions of a redox-imbalanced genotype incapable of growth were confirmed in vivo, and a mutant strain was used as a platform to probe redox bottlenecks in the central metabolism that hinder efficient ethanol production. The results highlight the robustness of the redox metabolism of C. thermocellum and the necessity of streamlined electron flux from reduced ferredoxin to NAD(P)H for high ethanol production. The model was further used to design a metabolic engineering strategy to phenotypically constrain C. thermocellum to achieve high ethanol yields while requiring minimal genetic manipulations. Furthermore, the model can be applied to design C. thermocellum as a platform microbe for consolidated bioprocessing to produce ethanol and other reduced metabolites.« less

Design methodology for integrated downstream separation systems in an ethanol biorefinery

NASA Astrophysics Data System (ADS)

Mohammadzadeh Rohani, Navid

Energy security and environmental concerns have been the main drivers for a historic shift to biofuel production in transportation fuel industry. Biofuels should not only offer environmental advantages over the petroleum fuels they replace but also should be economically sustainable and viable. The so-called second generation biofuels such as ethanol which is the most produced biofuel are mostly derived from lignocellulosic biomasses. These biofuels are more difficult to produce than the first generation ones mainly due to recalcitrance of the feedstocks in extracting their sugar contents. Costly pre-treatment and fractionation stages are required to break down lignocellulosic feedstocks into their constituent elements. On the other hand the mixture produced in fermentation step in a biorefinery contains very low amount of product which makes the subsequent separation step more difficult and more energy consuming. In an ethanol biorefinery, the dilute fermentation broth requires huge operating cost in downstream separation for recovery of the product in a conventional distillation technique. Moreover, the non-ideal nature of ethanol-water mixture which forms an iseotrope at almost 95 wt%, hinders the attainment of the fuel grade ethanol (99.5 wt%). Therefore, an additional dehydration stage is necessary to purify the ethanol from its azeotropic composition to fuel-grade purity. In order to overcome the constraint pertaining to vapor-liquid equilibrium of ethanol-water separation, several techniques have been investigated and proposed in the industry. These techniques such as membrane-based technologies, extraction and etc. have not only sought to produce a pure fuel-grade ethanol but have also aimed at decreasing the energy consumption of this energy-intensive separation. Decreasing the energy consumption of an ethanol biorefinery is of paramount importance in improving its overall economics and in facilitating the way to displacing petroleum transportation fuel and obtaining energy security. On the other hand, Process Integration (PI) as defined by Natural Resource Canada as the combination of activities which aim at improving process systems, their unit operations and their interactions in order to maximize the efficiency of using water, energy and raw materials can also help biorefineries lower their energy consumptions and improve their economics. Energy integration techniques such as pinch analysis adopted by different industries over the years have ensured using heat sources within a plant to supply the demand internally and decrease the external utility consumption. Therefore, adopting energy integration can be one of the ways biorefinery technology owners can consider in their process development as well as their business model in order to improve their overall economics. The objective of this thesis is to propose a methodology for designing integrated downstream separation in a biorefinery. This methodology is tested in an ethanol biorefinery case study. Several alternative separation techniques are evaluated in their energy consumption and economics in three different scenarios; stand-alone without energy integration, stand-alone with internal energy integration and integrated-with Kraft. The energy consumptions and capital costs of separation techniques are assessed in each scenario and the cost and benefit of integration are determined and finally the best alternative is found through techno-economic metrics. Another advantage of this methodology is the use of a graphical tool which provides insights on decreasing energy consumption by modifying the process condition. The pivot point of this work is the use of a novel energy integration method called Bridge analysis. This systematic method which originally is intended for retrofit situation is used here for integration with Kraft process. Integration potentials are identified through this method and savings are presented for each design. In stand-alone with internal integration scenario, the conventional pinch method is used for energy analysis. The results reveal the importance of energy integration in reducing energy consumption. They also show that in an ethanol biorefinery, by adopting energy integration in the conventional distillation separation, we can achieve greater energy saving compared to other alternative techniques. This in turn suggests that new alternative technologies which imply big risks for the company might not be an option for reducing the energy consumption as long as an internal and external integration is incorporated in the business model of an ethanol biorefinery. It is also noteworthy that the methodology developed in this work can be extended as a future work to include a whole biorefinery system. (Abstract shortened by UMI.).

Alternative Fuels Data Center: Ethanol Fuel Basics

Science.gov Websites

ethanol. Ethanol Energy Balance In the United States, 95% of ethanol is produced from the starch in corn demonstrates a positive energy balance, meaning that the process of producing ethanol fuel does not require energy balance of ethanol because the feedstocks are either waste, co-products of another industry (wood

Enhanced energy conversion efficiency from high strength synthetic organic wastewater by sequential dark fermentative hydrogen production and algal lipid accumulation.

PubMed

Ren, Hong-Yu; Liu, Bing-Feng; Kong, Fanying; Zhao, Lei; Xing, Defeng; Ren, Nan-Qi

2014-04-01

A two-stage process of sequential dark fermentative hydrogen production and microalgal cultivation was applied to enhance the energy conversion efficiency from high strength synthetic organic wastewater. Ethanol fermentation bacterium Ethanoligenens harbinense B49 was used as hydrogen producer, and the energy conversion efficiency and chemical oxygen demand (COD) removal efficiency reached 18.6% and 28.3% in dark fermentation. Acetate was the main soluble product in dark fermentative effluent, which was further utilized by microalga Scenedesmus sp. R-16. The final algal biomass concentration reached 1.98gL(-1), and the algal biomass was rich in lipid (40.9%) and low in protein (23.3%) and carbohydrate (11.9%). Compared with single dark fermentation stage, the energy conversion efficiency and COD removal efficiency of two-stage system remarkably increased 101% and 131%, respectively. This research provides a new approach for efficient energy production and wastewater treatment using a two-stage process combining dark fermentation and algal cultivation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Alternative Fuels Data Center: County Fleet Goes Big on Idle Reduction,

Science.gov Websites

Ethanol Use, Fuel Efficiency County Fleet Goes Big on Idle Reduction, Ethanol Use, Fuel , Ethanol Use, Fuel Efficiency on Facebook Tweet about Alternative Fuels Data Center: County Fleet Goes Big on Idle Reduction, Ethanol Use, Fuel Efficiency on Twitter Bookmark Alternative Fuels Data Center

Development of efficient, integrated cellulosic biorefineries : LDRD final report.

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

Teh, Kwee-Yan; Hecht, Ethan S.; Shaddix, Christopher R.

2010-09-01

Cellulosic ethanol, generated from lignocellulosic biomass sources such as grasses and trees, is a promising alternative to conventional starch- and sugar-based ethanol production in terms of potential production quantities, CO{sub 2} impact, and economic competitiveness. In addition, cellulosic ethanol can be generated (at least in principle) without competing with food production. However, approximately 1/3 of the lignocellulosic biomass material (including all of the lignin) cannot be converted to ethanol through biochemical means and must be extracted at some point in the biochemical process. In this project we gathered basic information on the prospects for utilizing this lignin residue material inmore » thermochemical conversion processes to improve the overall energy efficiency or liquid fuel production capacity of cellulosic biorefineries. Two existing pretreatment approaches, soaking in aqueous ammonia (SAA) and the Arkenol (strong sulfuric acid) process, were implemented at Sandia and used to generated suitable quantities of residue material from corn stover and eucalyptus feedstocks for subsequent thermochemical research. A third, novel technique, using ionic liquids (IL) was investigated by Sandia researchers at the Joint Bioenergy Institute (JBEI), but was not successful in isolating sufficient lignin residue. Additional residue material for thermochemical research was supplied from the dilute-acid simultaneous saccharification/fermentation (SSF) pilot-scale process at the National Renewable Energy Laboratory (NREL). The high-temperature volatiles yields of the different residues were measured, as were the char combustion reactivities. The residue chars showed slightly lower reactivity than raw biomass char, except for the SSF residue, which had substantially lower reactivity. Exergy analysis was applied to the NREL standard process design model for thermochemical ethanol production and from a prototypical dedicated biochemical process, with process data supplied by a recent report from the National Research Council (NRC). The thermochemical system analysis revealed that most of the system inefficiency is associated with the gasification process and subsequent tar reforming step. For the biochemical process, the steam generation from residue combustion, providing the requisite heating for the conventional pretreatment and alcohol distillation processes, was shown to dominate the exergy loss. An overall energy balance with different potential distillation energy requirements shows that as much as 30% of the biomass energy content may be available in the future as a feedstock for thermochemical production of liquid fuels.« less

Critical Zone Services as Environmental Assessment Criteria in Intensively Managed Agricultural Landscapes

NASA Astrophysics Data System (ADS)

Richardson, M.; Kumar, P.

2016-12-01

The critical zone (CZ) includes the biophysical processes occurring from the top of the vegetation canopy to the weathering zone below the groundwater table. CZ services provide a measure for the goods and benefits derived from CZ processes. In intensively managed landscapes (IML), the provisioning, supporting, and regulating services are altered through anthropogenic energy inputs to derive more productivity, as agricultural products, from these landscapes than would be possible under natural conditions. However, the energy or cost equivalents of alterations to CZ functions within landscape profiles are unknown. The valuation of CZ services in energy or monetary terms provides a more concrete tool for characterizing seemingly abstract environmental damages from agricultural production systems. A multi-layer canopy-root-soil model is combined with nutrient and water flux models to simulate the movement of nutrients throughout the soil system. This data enables the measurement of agricultural anthropogenic impacts to the CZ's nutrient cycling supporting services and atmospheric stabilizing regulating services defined by the flux of carbon and nutrients. Such measurements include soil carbon storage, soil carbon respiration, nitrate leaching, and nitrous oxide flux into the atmosphere. Additionally, the socioeconomic values of corn feed and ethanol define the primary productivity supporting services of each crop use.In the debate between feed production and corn-based ethanol production, measured nutrient CZ services can cost up to four times more than traditionally estimated CO2 equivalences for the entire bioenergy production system. Energy efficiency in addition to environmental impacts demonstrate how the inclusion of CZ services is necessary in accounting for the entire life cycle of agricultural production systems. These results conclude that feed production systems are more energy efficient and less environmentally costly than corn-based ethanol systems.

Performance and emissions characteristics of aqueous alcohol fumes in a DI diesel engine

NASA Technical Reports Server (NTRS)

Heisey, J. B.; Lestz, S. S.

1981-01-01

A single cylinder DI Diesel engine was fumigated with ethanol and methanol in amounts up to 55% of the total fuel energy. The effects of aqueous alcohol fumigation on engine thermal efficiency, combustion intensity and gaseous exhaust emissions were determined. Assessment of changes in the biological activity of raw particulate and its soluble organic fraction were also made using the Salmonella typhimurium test. Alcohol fumigation improved thermal efficiency slightly at moderate and heavy loads, but increased ignition delay at all operating conditions. Carbon monoxide and unburned hydrocarbon emission generally increased with alcohol fumigation and showed no dependence on alcohol type or quality. Oxide of nitrogen emission showed a strong dependence on alcohol quality; relative emission levels decreased with increasing water content of the fumigant. Particulate mass loading rates were lower for ethanol fueled conditions. However, the biological activity of both the raw particulate and its soluble organic fraction was enhanced by ethanol fumigation at most operating conditions.

Optimization of pretreatment, enzymatic hydrolysis and fermentation for more efficient ethanol production by Jerusalem artichoke stalk.

PubMed

Li, Kai; Qin, Jin-Cheng; Liu, Chen-Guang; Bai, Feng-Wu

2016-12-01

Jerusalem artichoke (JA) is a potential energy crop for biorefinery due to its unique agronomic traits such as resistance to environmental stresses and high biomass yield in marginal lands. Although JA tubers have been explored for inulin extraction and biofuels production, there is little concern on its stalk (JAS). In this article, the pretreatment of JAS by alkaline hydrogen peroxide was optimized using the response surface methodology to improve sugars yield and reduce chemicals usage. Scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis were applied to characterize the structures of the pretreated JAS to evaluate the effectiveness of the pretreatment. Furthermore, the feeding of the pretreated JAS and cellulase was performed for high solid uploading (up to 30%) to increase ethanol titer, and simultaneous saccharification and fermentation with 55.6g/L ethanol produced, 36.5% more than that produced through separate hydrolysis and fermentation, was validated to be more efficient. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ultrasonic pretreatment for enhanced saccharification and fermentation of ethanol production from corn

NASA Astrophysics Data System (ADS)

Montalbo-Lomboy, Melissa T.

The 21st Century human lifestyle has become heavily dependent on hydrocarbon inputs. Energy demand and the global warming effects due to the burning of fossil fuels have continued to increase. Rising awareness of the negative environmental and economic impacts of hydrocarbon dependence has led to a resurgence of interest in renewable energy sources such as ethanol. Fuel ethanol is known to be a cleaner and renewable source of energy relative to gasoline. Many studies have agreed that fuel ethanol has reduced greenhouse gas (GHG) emissions and has larger overall energy benefits compared to gasoline. Currently, the majority of the fuel ethanol in the United States is produced from corn using dry-grind milling process. The typical dry-grind ethanol plant incorporates jet cooking using steam to cook the corn slurry as pretreatment for saccharification; an energy intensive step. In aiming to reduce energy usage, this study evaluated the use of ultrasonics as an alternative to jet cooking. Ultrasonic batch experiments were conducted using a Branson 2000 Series bench-scale ultrasonic unit operating at a frequency of 20 kHz and a maximum output of 2.2 kW. Corn slurry was sonicated at varying amplitudes from 192 to 320 mumpeak-to-peak(p-p) for 0-40 seconds. Enzyme stability was investigated by adding enzyme (STARGEN(TM)001) before and after sonication. Scanning electron micrograph (SEM) images and particle size distribution analysis showed a nearly 20-fold size reduction by disintegration of corn particles due to ultrasonication. The results also showed a 30% improvement in sugar release of sonicated samples relative to the control group (untreated). The efficiency exceeded 100% in terms of relative energy gain from the additional sugar released due to ultrasonication compared to the ultrasonic energy applied. Interestingly, enzymatic activity was enhanced when sonicated at low and medium power. This result suggested that ultrasonic energy did not denature the enzymes during pretreatment. Ultrasonication of sugary-2 corn was also investigated in the study. Results similar to those for commodity corn (dent corn) were found, in terms of glucose yield and starch conversion. SEM and polarized-light microscope pictures showed the partial gelatinization of corn slurry due to ultrasound. In the 96-h saccharification time, a model was formulated to fit the sugar release curve. The results have shown 17-21% increase in the extent of sugar production from sonicated samples relative to the control group. Additionally, the reaction rates of the sonicated samples were 2- to 10-fold higher than the reaction rates for the control group. In comparing sugary-2 corn with commodity corn, it was found that sonicated sugary-2 corn saccharified faster than sonicated commodity corn. It is important to note, without ultrasonic treatment, sugary-2 corn released more reducing sugar than commodity corn during saccharification. To further investigate the potential of ultrasonics for scale-up, a continuous flow system was studied. An ultrasonic continuous flow system was tested using Branson's flow-through "donut" horn. The donut horn, which vibrates radially, was placed inside a 5.5 L stainless steel reactor. The amplitude was maintained at 12 mumpp and the feed flow rate was varied from 8-27 L/min (2-7 gal/min) with reactor retention times varying from 12-40 seconds. Samples sonicated in continuous flow system showed lower reducing sugar yield than batch ultrasonication. However, considering the ultrasonic energy density of batch and continuous systems, the continuous systems proved to be more energy efficient in terms of glucose production compared with the batch system. It was also seen that particle size disintegration was proportional to energy density regardless of the type of ultrasonic system used. To compare ultrasonics with jet cooking, fermentation experiments were conducted. There were only marginal differences between jet cooked samples and the sonicated samples in terms of ethanol conversion based on theoretical yield. Furthermore, statistical analysis confirmed that there was no significant difference (p<0.05) in the ethanol yields of the two pretreatment methods. Economic analysis indicated that the capital cost of installing ultrasonics was higher compared to jet cooker equipment. However, due to the energy needs of jet cooking, a typical 189 million liters (50 million gallon) per year ethanol plant ethanol plant would save about 16% in pretreatment cost by using ultrasonics. Based on these results, ultrasonication is a promising pretreatment method in corn ethanol production, as an alternative to jet cooking.

Engineering yeast consortia for surface-display of complex cellulosome structures

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

Chen, Wilfred

As our society marches toward a more technologically advanced future, energy and environmental sustainability are some of the most challenging problems we face today. Biomass is one of the most abundant renewable-feedstock for sustainable production of biofuels. However, the main technological obstacle to more widespread uses of this resource is the lack of low-cost technologies to overcome the recalcitrant nature of the cellulosic structure, especially the hydrolysis step on highly ordered celluloses. In this proposal, we successfully engineered several efficient and inexpensive whole-cell biocatalysts in an effort to produce economically compatible and sustainable biofuels, namely cellulosic ethanol. Our approach wasmore » to display of a highly efficient cellulolytic enzyme complex, named cellulosome, on the surface of a historical ethanol producer Saccharomyces cerevisiae for the simultaneous and synergistic saccharification and fermentation of cellulose to ethanol. We first demonstrated the feasibility of assembling a mini-cellulosome by incubating E. coli lysates expressing three different cellulases. Resting cells displaying mini-cellulosomes produced 4-fold more ethanol from phosphoric acid-swollen cellulose (PASC) than cultures with only added enzymes. The flexibility to assemble the mini-cellulosome structure was further demonstrated using a synthetic yeast consortium through intracellular complementation. Direct ethanol production from PASC was demonstrated with resting cell cultures. To create a microorganism suitable for a more cost-effective process, called consolidated bioprocessing (CBP), a synthetic consortium capable of displaying mini-cellulosomes on the cell surface via intercellular complementation was created. To further improve the efficiency, a new adaptive strategy of employing anchoring and adaptor scaffoldins to amplify the number of enzymatic subunits was developed, resulting in the creation of an artificial tetravalent cellulosome on the yeast surface and a significant improvement in cellulosic ethanol production. Although this adaptive strategy is ideal for assembling more complex cellulosome for large-scale production of cellulosic ethanol, a substantially larger number of enzymes (up to 10 to 12) is needed to better mimic the natural cellulosome structures for practical usage of the technology.« less

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.

Two stage bioethanol refining with multi litre stacked microbial fuel cell and microbial electrolysis cell.

PubMed

Sugnaux, Marc; Happe, Manuel; Cachelin, Christian Pierre; Gloriod, Olivier; Huguenin, Gérald; Blatter, Maxime; Fischer, Fabian

2016-12-01

Ethanol, electricity, hydrogen and methane were produced in a two stage bioethanol refinery setup based on a 10L microbial fuel cell (MFC) and a 33L microbial electrolysis cell (MEC). The MFC was a triple stack for ethanol and electricity co-generation. The stack configuration produced more ethanol with faster glucose consumption the higher the stack potential. Under electrolytic conditions ethanol productivity outperformed standard conditions and reached 96.3% of the theoretically best case. At lower external loads currents and working potentials oscillated in a self-synchronized manner over all three MFC units in the stack. In the second refining stage, fermentation waste was converted into methane, using the scale up MEC stack. The bioelectric methanisation reached 91% efficiency at room temperature with an applied voltage of 1.5V using nickel cathodes. The two stage bioethanol refining process employing bioelectrochemical reactors produces more energy vectors than is possible with today's ethanol distilleries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Establishment and assessment of a novel cleaner production process of corn grain fuel ethanol.

PubMed

Wang, Ke; Zhang, Jianhua; Tang, Lei; Zhang, Hongjian; Zhang, Guiying; Yang, Xizhao; Liu, Pei; Mao, Zhonggui

2013-11-01

An integrated corn ethanol-methane fermentation system was proposed to solve the problem of stillage handling, where thin stillage was treated by anaerobic digestion and then reused to make mash for the following ethanol fermentation. This system was evaluated at laboratory and pilot scale. Anaerobic digestion of thin stillage ran steadily with total chemical oxygen demand removal efficiency of 98% at laboratory scale and 97% at pilot scale. Ethanol production was not influenced by recycling anaerobic digestion effluent at laboratory and pilot scale. Compared with dried distillers' grains with solubles produced in conventional process, dried distillers' grains in the proposed system exhibited higher quality because of increased protein concentration and decreased salts concentration. Energetic assessment indicated that application of this novel process enhanced the net energy balance ratio from 1.26 (conventional process) to 1.76. In conclusion, the proposed system possessed technical advantage over the conventional process for corn fuel ethanol production. Copyright © 2013 Elsevier Ltd. All rights reserved.

Pyruvate decarboxylase and alcohol dehydrogenase overexpression in Escherichia coli resulted in high ethanol production and rewired metabolic enzyme networks.

PubMed

Yang, Mingfeng; Li, Xuefeng; Bu, Chunya; Wang, Hui; Shi, Guanglu; Yang, Xiushan; Hu, Yong; Wang, Xiaoqin

2014-11-01

Pyruvate decarboxylase and alcohol dehydrogenase are efficient enzymes for ethanol production in Zymomonas mobilis. These two enzymes were over-expressed in Escherichia coli, a promising candidate for industrial ethanol production, resulting in high ethanol production in the engineered E. coli. To investigate the intracellular changes to the enzyme overexpression for homoethanol production, 2-DE and LC-MS/MS were performed. More than 1,000 protein spots were reproducibly detected in the gel by image analysis. Compared to the wild-type, 99 protein spots showed significant changes in abundance in the recombinant E. coli, in which 46 were down-regulated and 53 were up-regulated. Most proteins related to tricarboxylic acid cycle, glycerol metabolism and other energy metabolism were up-regulated, whereas proteins involved in glycolysis and glyoxylate pathway were down-regulated, indicating the rewired metabolism in the engineered E. coli. As glycolysis is the main pathway for ethanol production, and it was inhibited significantly in engineered E. coli, further efforts should be directed at minimizing the repression of glycolysis to optimize metabolism network for higher yields of ethanol production.

A novel cost-effective technology to convert sucrose and homocelluloses in sweet sorghum stalks into ethanol.

PubMed

Li, Jihong; Li, Shizhong; Han, Bing; Yu, Menghui; Li, Guangming; Jiang, Yan

2013-11-29

Sweet sorghum is regarded as a very promising energy crop for ethanol production because it not only supplies grain and sugar, but also offers lignocellulosic resource. Cost-competitive ethanol production requires bioconversion of all carbohydrates in stalks including of both sucrose and lignocellulose hydrolyzed into fermentable sugars. However, it is still a main challenge to reduce ethanol production cost and improve feasibility of industrial application. An integration of the different operations within the whole process is a potential solution. An integrated process combined advanced solid-state fermentation technology (ASSF) and alkaline pretreatment was presented in this work. Soluble sugars in sweet sorghum stalks were firstly converted into ethanol by ASSF using crushed stalks directly. Then, the operation combining ethanol distillation and alkaline pretreatment was performed in one distillation-reactor simultaneously. The corresponding investigation indicated that the addition of alkali did not affect the ethanol recovery. The effect of three alkalis, NaOH, KOH and Ca(OH)2 on pretreatment were investigated. The results indicated the delignification of lignocellulose by NaOH and KOH was more significant than that by Ca(OH)2, and the highest removal of xylan was caused by NaOH. Moreover, an optimized alkali loading of 10% (w/w DM) NaOH was determined. Under this favorable pretreatment condition, enzymatic hydrolysis of sweet sorghum bagasse following pretreatment was investigated. 92.0% of glucan and 53.3% of xylan conversion were obtained at enzyme loading of 10 FPU/g glucan. The fermentation of hydrolyzed slurry was performed using an engineered stain, Zymomonas mobilis TSH-01. A mass balance of the overall process was calculated, and 91.9 kg was achieved from one tonne of fresh sweet sorghum stalk. A low energy-consumption integrated technology for ethanol production from sweet sorghum stalks was presented in this work. Energy consumption for raw materials preparation and pretreatment were reduced or avoided in our process. Based on this technology, the recalcitrance of lignocellulose was destructed via a cost-efficient process and all sugars in sweet sorghum stalks lignocellulose were hydrolysed into fermentable sugars. Bioconversion of fermentable sugars released from sweet sorghum bagasse into different products except ethanol, such as butanol, biogas, and chemicals was feasible to operate under low energy-consumption conditions.

A novel cost-effective technology to convert sucrose and homocelluloses in sweet sorghum stalks into ethanol

PubMed Central

2013-01-01

Background Sweet sorghum is regarded as a very promising energy crop for ethanol production because it not only supplies grain and sugar, but also offers lignocellulosic resource. Cost-competitive ethanol production requires bioconversion of all carbohydrates in stalks including of both sucrose and lignocellulose hydrolyzed into fermentable sugars. However, it is still a main challenge to reduce ethanol production cost and improve feasibility of industrial application. An integration of the different operations within the whole process is a potential solution. Results An integrated process combined advanced solid-state fermentation technology (ASSF) and alkaline pretreatment was presented in this work. Soluble sugars in sweet sorghum stalks were firstly converted into ethanol by ASSF using crushed stalks directly. Then, the operation combining ethanol distillation and alkaline pretreatment was performed in one distillation-reactor simultaneously. The corresponding investigation indicated that the addition of alkali did not affect the ethanol recovery. The effect of three alkalis, NaOH, KOH and Ca(OH)2 on pretreatment were investigated. The results indicated the delignification of lignocellulose by NaOH and KOH was more significant than that by Ca(OH)2, and the highest removal of xylan was caused by NaOH. Moreover, an optimized alkali loading of 10% (w/w DM) NaOH was determined. Under this favorable pretreatment condition, enzymatic hydrolysis of sweet sorghum bagasse following pretreatment was investigated. 92.0% of glucan and 53.3% of xylan conversion were obtained at enzyme loading of 10 FPU/g glucan. The fermentation of hydrolyzed slurry was performed using an engineered stain, Zymomonas mobilis TSH-01. A mass balance of the overall process was calculated, and 91.9 kg was achieved from one tonne of fresh sweet sorghum stalk. Conclusions A low energy-consumption integrated technology for ethanol production from sweet sorghum stalks was presented in this work. Energy consumption for raw materials preparation and pretreatment were reduced or avoided in our process. Based on this technology, the recalcitrance of lignocellulose was destructed via a cost-efficient process and all sugars in sweet sorghum stalks lignocellulose were hydrolysed into fermentable sugars. Bioconversion of fermentable sugars released from sweet sorghum bagasse into different products except ethanol, such as butanol, biogas, and chemicals was feasible to operate under low energy-consumption conditions. PMID:24286508

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.

Process simulation of ethanol production from biomass gasification and syngas fermentation.

PubMed

Pardo-Planas, Oscar; Atiyeh, Hasan K; Phillips, John R; Aichele, Clint P; Mohammad, Sayeed

2017-12-01

The hybrid gasification-syngas fermentation platform can produce more bioethanol utilizing all biomass components compared to the biochemical conversion technology. Syngas fermentation operates at mild temperatures and pressures and avoids using expensive pretreatment processes and enzymes. This study presents a new process simulation model developed with Aspen Plus® of a biorefinery based on a hybrid conversion technology for the production of anhydrous ethanol using 1200tons per day (wb) of switchgrass. The simulation model consists of three modules: gasification, fermentation, and product recovery. The results revealed a potential production of about 36.5million gallons of anhydrous ethanol per year. Sensitivity analyses were also performed to investigate the effects of gasification and fermentation parameters that are keys for the development of an efficient process in terms of energy conservation and ethanol production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Potential use and the energy conversion efficiency analysis of fermentation effluents from photo and dark fermentative bio-hydrogen production.

PubMed

Zhang, Zhiping; Li, Yameng; Zhang, Huan; He, Chao; Zhang, Quanguo

2017-12-01

Effluent of bio-hydrogen production system also can be adopted to produce methane for further fermentation, cogeneration of hydrogen and methane will significantly improve the energy conversion efficiency. Platanus Orientalis leaves were taken as the raw material for photo- and dark-fermentation bio-hydrogen production. The resulting concentrations of acetic, butyric, and propionic acids and ethanol in the photo- and dark-fermentation effluents were 2966mg/L and 624mg/L, 422mg/L and 1624mg/L, 1365mg/L and 558mg/L, and 866mg/L and 1352mg/L, respectively. Subsequently, we calculated the energy conversion efficiency according to the organic contents of the effluents and their energy output when used as raw material for methane production. The overall energy conversion efficiencies increased by 15.17% and 22.28%, respectively, when using the effluents of photo and dark fermentation. This two-step bio-hydrogen and methane production system can significantly improve the energy conversion efficiency of anaerobic biological treatment plants. Copyright © 2017. Published by Elsevier Ltd.

Energy and precious fuels requirements of fuel alcohol production. Volume 2, appendices A and B: Ethanol from grain

NASA Technical Reports Server (NTRS)

Weinblatt, H.; Reddy, T. S.; Turhollow, A., Jr.

1982-01-01

Energy currently used in grain production, the effect of ethanol production on agricultural energy consumption, energy credits for ethanol by-products, and land availability and the potential for obtaining ethanol from grain are discussed. Dry milling, wet milling, sensitivity analysis, potential for reduced energy consumption are also discussed.

CPERC CONSORTIUM

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

Boopathy, Ramaraj

2012-12-31

CPERC’s activities focused on two major themes: (a) cost-effective production of next-generation fuels with a focus on hydrogen from gasification and biofuels (primarily ethanol and butanol), and (b) efficient utilization of hydrogen and biofuels for power generation with a focus on improved performance, greater reliability and reduced energy costs.

Land usage attributed to corn ethanol production in the United States: sensitivity to technological advances in corn grain yield, ethanol conversion, and co-product utilization.

PubMed

Mumm, Rita H; Goldsmith, Peter D; Rausch, Kent D; Stein, Hans H

2014-01-01

Although the system for producing yellow corn grain is well established in the US, its role among other biofeedstock alternatives to petroleum-based energy sources has to be balanced with its predominant purpose for food and feed as well as economics, land use, and environmental stewardship. We model land usage attributed to corn ethanol production in the US to evaluate the effects of anticipated technological change in corn grain production, ethanol processing, and livestock feeding through a multi-disciplinary approach. Seven scenarios are evaluated: four considering the impact of technological advances on corn grain production, two focused on improved efficiencies in ethanol processing, and one reflecting greater use of ethanol co-products (that is, distillers dried grains with solubles) in diets for dairy cattle, pigs, and poultry. For each scenario, land area attributed to corn ethanol production is estimated for three time horizons: 2011 (current), the time period at which the 15 billion gallon cap for corn ethanol as per the Renewable Fuel Standard is achieved, and 2026 (15 years out). Although 40.5% of corn grain was channeled to ethanol processing in 2011, only 25% of US corn acreage was attributable to ethanol when accounting for feed co-product utilization. By 2026, land area attributed to corn ethanol production is reduced to 11% to 19% depending on the corn grain yield level associated with the four corn production scenarios, considering oil replacement associated with the soybean meal substituted in livestock diets with distillers dried grains with solubles. Efficiencies in ethanol processing, although producing more ethanol per bushel of processed corn, result in less co-products and therefore less offset of corn acreage. Shifting the use of distillers dried grains with solubles in feed to dairy cattle, pigs, and poultry substantially reduces land area attributed to corn ethanol production. However, because distillers dried grains with solubles substitutes at a higher rate for soybean meal, oil replacement requirements intensify and positively feedback to elevate estimates of land usage. Accounting for anticipated technological changes in the corn ethanol system is important for understanding the associated land base ascribed, and may aid in calibrating parameters for land use models in biofuel life-cycle analyses.

Land usage attributed to corn ethanol production in the United States: sensitivity to technological advances in corn grain yield, ethanol conversion, and co-product utilization

PubMed Central

2014-01-01

Background Although the system for producing yellow corn grain is well established in the US, its role among other biofeedstock alternatives to petroleum-based energy sources has to be balanced with its predominant purpose for food and feed as well as economics, land use, and environmental stewardship. We model land usage attributed to corn ethanol production in the US to evaluate the effects of anticipated technological change in corn grain production, ethanol processing, and livestock feeding through a multi-disciplinary approach. Seven scenarios are evaluated: four considering the impact of technological advances on corn grain production, two focused on improved efficiencies in ethanol processing, and one reflecting greater use of ethanol co-products (that is, distillers dried grains with solubles) in diets for dairy cattle, pigs, and poultry. For each scenario, land area attributed to corn ethanol production is estimated for three time horizons: 2011 (current), the time period at which the 15 billion gallon cap for corn ethanol as per the Renewable Fuel Standard is achieved, and 2026 (15 years out). Results Although 40.5% of corn grain was channeled to ethanol processing in 2011, only 25% of US corn acreage was attributable to ethanol when accounting for feed co-product utilization. By 2026, land area attributed to corn ethanol production is reduced to 11% to 19% depending on the corn grain yield level associated with the four corn production scenarios, considering oil replacement associated with the soybean meal substituted in livestock diets with distillers dried grains with solubles. Efficiencies in ethanol processing, although producing more ethanol per bushel of processed corn, result in less co-products and therefore less offset of corn acreage. Shifting the use of distillers dried grains with solubles in feed to dairy cattle, pigs, and poultry substantially reduces land area attributed to corn ethanol production. However, because distillers dried grains with solubles substitutes at a higher rate for soybean meal, oil replacement requirements intensify and positively feedback to elevate estimates of land usage. Conclusions Accounting for anticipated technological changes in the corn ethanol system is important for understanding the associated land base ascribed, and may aid in calibrating parameters for land use models in biofuel life-cycle analyses. PMID:24725504

Agricultural policies and biomass fuels

NASA Astrophysics Data System (ADS)

Flaim, S.; Hertzmark, D.

The potentials for biomass energy derived from agricultural products are examined. The production of energy feedstocks from grains is discussed for the example of ethanol production from grain, with consideration given to the beverage process and the wet milling process for obtaining fuel ethanol from grains and sugars, the nonfeedstock costs and energy requirements for ethanol production, the potential net energy gain from ethanol fermentation, the effect of ethanol fuel production on supplies of protein, oils and feed and of ethanol coproducts, net ethanol costs, and alternatives to corn as an ethanol feedstock. Biomass fuel production from crop residues is then considered; the constraints of soil fertility on crop residue removal for energy production are reviewed, residue yields with conventional practices and with reduced tillage are determined, technologies for the direct conversion of cellulose to ethanol and methanol are described, and potential markets for the products of these processes are identified. Implications for agricultural policy of ethanol production from grain and fuel and chemical production from crop residues are also discussed.

Biological conversion assay using Clostridium phytofermentans to estimate plant feedstock quality.

PubMed

Lee, Scott J; Warnick, Thomas A; Pattathil, Sivakumar; Alvelo-Maurosa, Jesús G; Serapiglia, Michelle J; McCormick, Heather; Brown, Virginia; Young, Naomi F; Schnell, Danny J; Smart, Lawrence B; Hahn, Michael G; Pedersen, Jeffrey F; Leschine, Susan B; Hazen, Samuel P

2012-02-08

There is currently considerable interest in developing renewable sources of energy. One strategy is the biological conversion of plant biomass to liquid transportation fuel. Several technical hurdles impinge upon the economic feasibility of this strategy, including the development of energy crops amenable to facile deconstruction. Reliable assays to characterize feedstock quality are needed to measure the effects of pre-treatment and processing and of the plant and microbial genetic diversity that influence bioconversion efficiency. We used the anaerobic bacterium Clostridium phytofermentans to develop a robust assay for biomass digestibility and conversion to biofuels. The assay utilizes the ability of the microbe to convert biomass directly into ethanol with little or no pre-treatment. Plant samples were added to an anaerobic minimal medium and inoculated with C. phytofermentans, incubated for 3 days, after which the culture supernatant was analyzed for ethanol concentration. The assay detected significant differences in the supernatant ethanol from wild-type sorghum compared with brown midrib sorghum mutants previously shown to be highly digestible. Compositional analysis of the biomass before and after inoculation suggested that differences in xylan metabolism were partly responsible for the differences in ethanol yields. Additionally, we characterized the natural genetic variation for conversion efficiency in Brachypodium distachyon and shrub willow (Salix spp.). Our results agree with those from previous studies of lignin mutants using enzymatic saccharification-based approaches. However, the use of C. phytofermentans takes into consideration specific organismal interactions, which will be crucial for simultaneous saccharification fermentation or consolidated bioprocessing. The ability to detect such phenotypic variation facilitates the genetic analysis of mechanisms underlying plant feedstock quality.

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

Sustainable energy policy: the impact of government subsidies on ethanol as a renewable fuel

NASA Astrophysics Data System (ADS)

Osuagwu, Denis Ahamarula

The United States Congress passed the Energy Policy Act of 1978 to promote ethanol production and reduce American dependence on foreign oil. The provision of subsidies in the act is indicative of the importance of energy in the economy. America needs a national energy policy that is economically, socially, and environmentally sustainable. Considering the importance of these needs, this study examines (a) the implementation of the Energy Policy Act of 1978 in regard to government subsidies and its effect on ethanol production, (b) the effect of gasoline consumption and cost on ethanol production, (c) the effect of corn production and price on ethanol fuel, and (d) the role of mandates and global crises on ethanol production. Secondary qualitative and quantitative data collected from various sources in 1978 through 2005 study the effect of ethanol subsidies on ethanol production. An autoregression error model is used to estimate the relevance of the explanatory variables on variations in ethanol production. The following are major study findings: (1) there is a positive correlation between corn production and ethanol production, is statistically significant; (2) government subsidies have a statistically significant positive correlation with ethanol production; (3) oil import has a statistically significant positive correlation with ethanol production, but has not contributed to a reduction the quantity of imported oil; (4) the price of corn has a statistically significant inverse relationship with ethanol production; (5) though not statistically significant, the price per barrel of oil is inversely related to ethanol production; (6) the budget surplus or deficit is associated with ethanol production; and (7) advocacy and lobbying for renewable fuel have encouraged support of ethanol production. The findings also show that global crises in the oil producing regions tend to influence the passage of favorable legislation for ethanol production. Furthermore, the incremental approach to implementation of alternative energy programs has been a failure. In the absence of a national energy regulation policy, oil import is on the increase; exacerbating American dependence on foreign supplies. A sustainable energy policy requires vision and commitment, but policymakers do not seem to command political capital to achieve this objective. Investigation reveals that subsidies have contributed in the production of ethanol. The four billion gallons of ethanol produced in 2005 is significantly higher than the quantity produced in 1978. However, an increase in ethanol production has made no considerable contribution to reducing American dependence on foreign oil. A sustainable energy policy requires a proactive public policy that includes public and private investment in renewable energy and technology, together with a continuance of local oil drilling.

Well-to-Wheels Greenhouse Gas Emission Analysis of High-Octane Fuels with Ethanol Blending: Phase II Analysis with Refinery Investment Options

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

Han, Jeongwoo; Wang, Michael; Elgowainy, Amgad

Higher-octane gasoline can enable increases in an internal combustion engine’s energy efficiency and a vehicle’s fuel economy by allowing an increase in the engine compression ratio and/or by enabling downspeeding and downsizing. Producing high-octane fuel (HOF) with the current level of ethanol blending (E10) could increase the energy and greenhouse gas (GHG) emissions intensity of the fuel product from refinery operations. Alternatively, increasing the ethanol blending level in final gasoline products could be a promising solution to HOF production because of the high octane rating and potentially low blended Reid vapor pressure (RVP) of ethanol at 25% and higher ofmore » the ethanol blending level by volume. In our previous HOF well-to-wheels (WTW) report (the so-called phase I report of the HOF WTW analysis), we conducted WTW analysis of HOF with different ethanol blending levels (i.e., E10, E25, and E40) and a range of vehicle efficiency gains with detailed petroleum refinery linear programming (LP) modeling by Jacobs Consultancy and showed that the overall WTW GHG emission changes associated with HOFVs were dominated by the positive impact associated with vehicle efficiency gains and ethanol blending levels, while the refining operations to produce gasoline blendstock for oxygenate blending (BOB) for various HOF blend levels had a much smaller impact on WTW GHG emissions (Han et al. 2015). The scope of the previous phase I study, however, was limited to evaluating PADDs 2 and 3 operation changes with various HOF market share scenarios and ethanol blending levels. Also, the study used three typical configuration models of refineries (cracking, light coking, and heavy coking) in each PADD, which may not be representative of the aggregate response of all refineries in each PADD to various ethanol blending levels and HOF market scenarios. Lastly, the phase I study assumed no new refinery expansion in the existing refineries, which limited E10 HOF production to the volume achievable by the cracking refinery configuration. To be able to satisfy large market demands of E10 HOF, that study arbitrarily relaxed the RVP requirements by replacing reformulated gasoline (RFG) RVP requirement of 7 psi in summer with conventional gasoline (CG) RVP requirement of 9 psi in summer. To examine the response by all refineries in major refinery regions, this phase II of the HOF WTW analysis employed regionally aggregated refinery models for the following six regions: PADDs 1, 2, 3, 4, and 5 excluding California (CA) and CA separately. Using aggregate refinery models, this phase II study examined the impacts of ethanol blending and HOF market shares on the refinery operations in these six regions. Also, this study included refinery expansion to produce a pre-determined HOF volume with 10% ethanol blending. In particular, this study examined several refinery expansion options using refinery configuration models to investigate a practical refinery response to the increase in E10 HOF market demand.« less

Production of hydrogen using nanocrystalline protein-templated catalysts on m13 phage.

PubMed

Neltner, Brian; Peddie, Brian; Xu, Alex; Doenlen, William; Durand, Keith; Yun, Dong Soo; Speakman, Scott; Peterson, Andrew; Belcher, Angela

2010-06-22

For decades, ethanol has been in use as a fuel for the storage of solar energy in an energy-dense, liquid form. Over the past decade, the ability to reform ethanol into hydrogen gas suitable for a fuel cell has drawn interest as a way to increase the efficiency of both vehicles and stand-alone power generators. Here we report the use of extremely small nanocrystalline materials to enhance the performance of 1% Rh/10% Ni@CeO(2) catalysts in the oxidative steam reforming of ethanol with a ratio of 1.7:1:10:11 (air/EtOH/water/argon) into hydrogen gas, achieving 100% conversion of ethanol at only 300 degrees C with 60% H(2) in the product stream and less than 0.5% CO. Additionally, nanocrystalline 10% Ni@CeO(2) was shown to achieve 100% conversion of ethanol at 400 degrees C with 73% H(2), 2% CO, and 2% CH(4) in the product stream. Finally, we demonstrate the use of biological templating on M13 to improve the resistance of this catalyst to deactivation over 52 h tests at high flow rates (120 000 h(-1) GHSV) at 450 degrees C. This study suggests that the use of highly nanocrystalline, biotemplated catalysts to improve activity and stability is a promising route to significant gains over traditional catalyst manufacture methods.

Utilization of acetone-butanol-ethanol-water mixture obtained from biomass fermentation as renewable feedstock for hydrogen production via steam reforming: Thermodynamic and energy analyses.

PubMed

Kumar, Brajesh; Kumar, Shashi; Sinha, Shishir; Kumar, Surendra

2018-08-01

A thermodynamic equilibrium analysis on steam reforming process to utilize acetone-butanol-ethanol-water mixture obtained from biomass fermentation as biorenewable fuel has been performed to produce clean energy carrier H 2 via non-stoichiometric approach namely Gibbs free energy minimization method. The effect of process variables such as temperature (573-1473 K), pressure (1-10 atm), and steam/fuel molar feed ratio (F ABE  = 5.5-12) have been investigated on equilibrium compositions of products, H 2 , CO, CO 2 , CH 4 and solid carbon. The best suitable conditions for maximization of desired product H 2 , suppression of CH 4 , and inhibition of solid carbon are 973 K, 1 atm, steam/fuel molar feed ratio = 12. Under these conditions, the maximum molar production of hydrogen is 8.35 with negligible formation of carbon and methane. Furthermore, the energy requirement per mol of H 2 (48.96 kJ), thermal efficiency (69.13%), exergy efficiency (55.09%), exergy destruction (85.36 kJ/mol), and generated entropy (0.29 kJ/mol.K) have been achieved at same operating conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Salinity-gradient energy driven microbial electrosynthesis of value-added chemicals from CO2 reduction.

PubMed

Li, Xiaohu; Angelidaki, Irini; Zhang, Yifeng

2018-06-14

Biological conversion of CO 2 to value-added chemicals and biofuels has emerged as an attractive strategy to address the energy and environmental concerns caused by the over-reliance on fossil fuels. In this study, an innovative microbial reverse-electrodialysis electrolysis cell (MREC), which combines the strengths of reverse electrodialysis (RED) and microbial electrosynthesis technology platforms, was developed to achieve efficient CO 2 -to-value chemicals bioconversion by using the salinity gradient energy as driven energy sources. In the MREC, maximum acetate and ethanol concentrations of 477.5 ± 33.2 and 46.2 ± 8.2 mg L -1 were obtained at the cathode, catalyzed by Sporomusa ovata with production rates of 165.79 ± 11.52 and 25.11 ± 4.46 mmol m -2 d -1 , respectively. Electron balance analysis indicates that 94.4 ± 3.9% of the electrons derived from wastewater and salinity gradient were recovered in acetate and ethanol. This work for the first time proved the potential of innovative MREC configuration has the potential as an efficient technology platform for simultaneous CO 2 capture and electrosynthesis of valuable chemicals. Copyright © 2018 Elsevier Ltd. All rights reserved.

Elucidating central metabolic redox obstacles hindering ethanol production in Clostridium thermocellum.

PubMed

Thompson, R Adam; Layton, Donovan S; Guss, Adam M; Olson, Daniel G; Lynd, Lee R; Trinh, Cong T

2015-11-01

Clostridium thermocellum is an anaerobic, Gram-positive, thermophilic bacterium that has generated great interest due to its ability to ferment lignocellulosic biomass to ethanol. However, ethanol production is low due to the complex and poorly understood branched metabolism of C. thermocellum, and in some cases overflow metabolism as well. In this work, we developed a predictive stoichiometric metabolic model for C. thermocellum which incorporates the current state of understanding, with particular attention to cofactor specificity in the atypical glycolytic enzymes and the complex energy, redox, and fermentative pathways with the goal of aiding metabolic engineering efforts. We validated the model's capability to encompass experimentally observed phenotypes for the parent strain and derived mutants designed for significant perturbation of redox and energy pathways. Metabolic flux distributions revealed significant alterations in key metabolic branch points (e.g., phosphoenol pyruvate, pyruvate, acetyl-CoA, and cofactor nodes) in engineered strains for channeling electron and carbon fluxes for enhanced ethanol synthesis, with the best performing strain doubling ethanol yield and titer compared to the parent strain. In silico predictions of a redox-imbalanced genotype incapable of growth were confirmed in vivo, and a mutant strain was used as a platform to probe redox bottlenecks in the central metabolism that hinder efficient ethanol production. The results highlight the robustness of the redox metabolism of C. thermocellum and the necessity of streamlined electron flux from reduced ferredoxin to NAD(P)H for high ethanol production. The model was further used to design a metabolic engineering strategy to phenotypically constrain C. thermocellum to achieve high ethanol yields while requiring minimal genetic manipulations. The model can be applied to design C. thermocellum as a platform microbe for consolidated bioprocessing to produce ethanol and other reduced metabolites. Copyright © 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

A comparison of the energy use of in situ product recovery techniques for the Acetone Butanol Ethanol fermentation.

PubMed

Outram, Victoria; Lalander, Carl-Axel; Lee, Jonathan G M; Davis, E Timothy; Harvey, Adam P

2016-11-01

The productivity of the Acetone Butanol Ethanol (ABE) fermentation can be significantly increased by application of various in situ product recovery (ISPR) techniques. There are numerous technically viable processes, but it is not clear which is the most economically viable in practice. There is little available information about the energy requirements and economics of ISPR for the ABE fermentation. This work compares various ISPR techniques based on UniSim process simulations of the ABE fermentation. The simulations provide information on the process energy and separation efficiency, which is fed into an economic assessment. Perstraction was the only technique to reduce the energy demand below that of a batch process, by approximately 5%. Perstraction also had the highest profit increase over a batch process, by 175%. However, perstraction is an immature technology, so would need significant development before being integrated to an industrial process. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

Energy production, distribution, and pollution controls: Combining engineering and economic analysis to enhance efficiency and policy design

NASA Astrophysics Data System (ADS)

Perkis, David F.

Three published articles are presented which focus on enhancing various aspects of the energy supply chain. While each paper adopts a different methodology, all three combine engineering data and/or techniques with economic analysis to improve efficiency or policy design within energy markets. The first paper combines a chemical engineering plant design model with an economic assessment of product enhancements within an ethanol production facility. While a new chemical process is shown to achieve greater ethanol yields, the animal feed by-products are denatured and decrease in value due to the degradation of a key nutritional amino acid. Overall, yield increases outweigh any costs, providing additional value to firms adopting this process. The second paper uses a mixed integer linear model to assess the optimal location of cellulosic ethanol production facilities within the state of Indiana. Desired locations with low costs are linked to regions with high yield corn growth, as these areas provide an abundance of corn stover, a by-product of corn and a cellulosic source of ethanol. The third paper implements experimental economic methods to assess the effectiveness of policies intended to control prices in emissions permit markets. When utilizing reserve permit auctions as an alternative to setting explicit maximum prices, prices are elevated beyond the theoretical predictions of the model within the conditions of the experiment. The most likely cause of higher prices is the negotiating power provided to sellers by grandfathering permits as evidenced by higher than expected welfare gains to sellers. Before presenting the articles, a discussion is introduced regarding the role of assumptions used by economists. For each article, a key assumption is highlighted and the consequences of making a different assumption are provided. Whether the consequences are large or small, the benefits of elucidating our models with assumptions based on real world behaviors are clearly demonstrated.

Efficiency of a solid polymer fuel cell operating on ethanol

NASA Astrophysics Data System (ADS)

Ioannides, Theophilos; Neophytides, Stylianos

The efficiency of a solid polymer fuel cell (SPFC) system operating on ethanol fuel has been analyzed as a function of operating parameters focusing on vehicle and stationary applications. Two types of ethanol processors — employing either steam reforming or partial oxidation (POX) steps — have been considered and their performance has been investigated by thermodynamic analysis. SPFC operation has been analyzed by an available parametric model. It has been found that dilute ethanol-water mixtures (˜55% v/v EtOH) are the most suitable for stationary applications with a steam reformer (SR)-SPFC system. Regarding vehicle applications, pure ethanol (˜95% v/v EtOH) appears to be the best fuel with a POX-SPFC system. Efficiencies in the case of an ideal ethanol processor can be of the order of 60% under low load conditions and 30-35% at peak power, while efficiencies with an actual processor are 80-85% of the above values.

Debris-free rear-side picosecond laser ablation of thin germanium wafers in water with ethanol

NASA Astrophysics Data System (ADS)

Zhang, Dongshi; Gökce, Bilal; Sommer, Steffen; Streubel, René; Barcikowski, Stephan

2016-03-01

In this paper, we perform liquid-assisted picosecond laser cutting of 150 μm thin germanium wafers from the rear side. By investigating the cutting efficiency (the ability to allow an one-line cut-through) and quality (characterized by groove morphologies on both sides), the pros and cons of this technique under different conditions are clarified. Specifically, with laser fluence fixed, repetition rate and scanning speed are varied to show quality and efficiency control by means of laser parameter modulation. It is found that low repetition rate ablation in liquid gives rise to a better cut quality on the front side than high repetition rate ablation since it avoids dispersed nanoparticles redeposition resulting from a bubble collapse, unlike the case of 100 kHz which leads to large nanorings near the grooves resulting from a strong interaction of bubbles and the case of 50 kHz which leads to random cutting due to the interaction of the former pulse induced cavitation bubble and the subsequent laser pulse. Furthermore, ethanol is mixed with pure distilled water to assess the liquid's impact on the cutting efficiency and cutting quality. The results show that increasing the ethanol fraction decreases the ablation efficiency but simultaneously, greatly improves the cutting quality. The improvement of cut quality as ethanol ratio increases may be attributed to less laser beam interference by a lower density of bubbles which adhere near the cut kerf during ablation. A higher density of bubbles generated from ethanol vaporization during laser ablation in liquid will cause stronger bubble shielding effect toward the laser beam propagation and therefore result in less laser energy available for the cut, which is the main reason for the decrease of cut efficiency in water-ethanol mixtures. Our findings give an insight into under which condition the rear-side laser cutting of thin solar cells should be performed: high repetition, pure distilled water and high laser power are favorable for high-speed rough cutting but the cut kerf suffers from strong side effects of ripples, nanoredeposition occurrence, while low laser power at low repetition rate (10 kHz), mixed solution (1 wt% ethanol in water) and moderate scanning speed (100 μm/s) are preferable for ultrafine high-quality debris-free cutting. The feasibility of high-quality cut is a good indication of using rear laser ablation in liquid to cut thinner wafers. More importantly, this technique spares any post cleaning steps to reduce the risk to the contamination or crack of the thin wafers.

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.

Development of a more efficient process for production of fuel ethanol from bamboo.

PubMed

Sun, Zhao-Yong; Wang, Ting; Tan, Li; Tang, Yue-Qin; Kida, Kenji

2015-06-01

A process for production of fuel ethanol from bamboo treated with concentrated sulfuric acid has been previously proposed. To improve efficiency of the process, we tested saccharification with 70 weight% (wt%) sulfuric acid, acid-sugar separation by ion exclusion, addition of nutrients to the ethanol fermentation, and bioconversion of xylose to xylitol. A high efficiency of both sugar recovery (82.5 %) and acid recovery (97.5 %) was achieved in the saccharification process and in the continuous acid-sugar separation using a modified anion exchange resin, respectively. Reduction of the amount of mineral salts added to the saccharified liquid after acid-sugar separation did not negatively affect performance of the continuous ethanol fermentation. The ethanol yield and productivity were 93.7 % and 6 g/l h, respectively, at 35 °C and pH 4.0. And the ethanol yield and productivity were almost the same even at pH 3.5. Moreover, the xylose remaining in the fermented mash was efficiently converted to xylitol in batch fermentation by Candida tropicalis strain 2.1776. These results demonstrate a more efficient process for the production of fuel ethanol from bamboo.

An Investigation of Cellulose Digesting Bacteria in the Camel Feces Microbiome

NASA Astrophysics Data System (ADS)

Man, V.; Leung, F. C.

2015-12-01

Research Question: Is there a bacteria in camel feces that digests cellulose material and can be used for waste to energy projects? Fossil fuels are the current main resource of energy in the modern world. However, as the demand for fuel increases, biofuels have been proposed as an alternative energy source that is a more sustainable form of liquid fuel generation from living things or waste, commonly known as biofuels and ethanol. The Camelus dromedarius', also known as Arabian camel, diet consist of grass, grains, wheat and oats as well desert vegetation in their natural habitat. However, as the Arabian camel lacks the enzymes to degrade cellulose, it is hypothesized that cellulose digestion is performed by microbial symbionts in camel microbiota. Fecal samples were collected from the Camelus dromedarius in United Arab Emirates and diluted 10-7 times. The diluted sample was then streaked onto a Sodium Carboxymethyl Cellulose plate, and inoculated onto CMC and Azure-B plates. Afterwards, Congo Red was used for staining in order to identify clearance zones of single colonies that may potentially be used as a qualitative assays for cellulose digestion. Then the colonies undergo polymerase chain reaction amplification to produce amplified RNA fragments. The 16S ribosomal RNA gene is identified based on BLAST result using Sanger Sequencing. Amongst the three identified microbes: Bacillus, Staphylococcus and Escherichia coli, both Bacillus and Staphylococcus are cellulose-digesting microbes, and through the fermentation of lignocellulosic, biomasses can be converted into cellulosic ethanol (Biofuel). According to the Improvements in Life Cycle Energy Efficiency and Greenhouse Gas Emissions of Corn-Ethanol by Adam J. Liska, ""Ethanol reduces greenhouse gas emissions by 40-50% when compared directly to gasoline." The determination of bacterial communities that are capable of efficiently and effectively digesting cellulose materials requires that the bacteria be first isolated and then a full genome characterization. This bacteria study is apart of a much larger study and will be tested against the gut microbiome of other animals successfully digesting cellulose to determine the ones that are best suited for biofuel production.

Evaluating energy efficient strategies and product quality for distillers' dried grains with solubles (DDGS) in dry-grind ethanol plants

NASA Astrophysics Data System (ADS)

Lan, Tian

The drying of distillers dried grains with solubles (DDGS), a coproduct of dry-grind corn processing to ethanol utilizes about 30% of the total energy required for the production of a liter of fuel ethanol. Therefore, improving DDGS drying energy efficiency could have significant impact on the economics of the dry-grind corn-to-ethanol process. Drying process improvements must take account into the effects of various drying strategies on the final quality of DDGS which is primarily utilized as a feed ingredient. Previous studies in the literature have shown that physical and chemical properties of DDGS vary according to the ratio of the two primarily feed streams, wet distillers grains (WDG) and condensed distillers solubles (CDS) which make up DDGS. Extensive research using plant-scale and bench-scale experiments have been conducted on the effect of process variables (ratios of WDG, CDS and DDGS add-back) during drying on the physical and chemical properties of DDGS. However, these investigations did not correlate the product characteristics data to drying efficiency. Additionally, it cannot be clearly determined from the literature on DDGS drying that processes used in the industry are optimized for both product quality and energy efficiency. A bench-scale rotary drum dryer heated by an electrically powered heat gun was used to investigate the effects of WDG, CDS and add-back ratios on both energy efficiency, drying performance and DDGS physical and chemical properties. A two stage drying process with the bench-scale rotary dryer was used to simulate the drying of DDGS using ICM (ICM, Inc., Colwich, KS) dry-grind process technology for DDGS drying which uses two rotary drum dryers in series. Effects of drying process variables, CDS content (0, 10, 20 and 40% by mass) and percent DDGS add-back (0, 20, 40 and 60% by mass) on energy performance and product quality were determined. Sixteen different drying strategies based on drying process variable ratios were tested and the response variables were measured which included energy performance (specific power consumption, energy efficiency, drying efficiency, drying rate), physical properties [particle size distribution (PSD), geometric mean particle size (dwg), bulk density, tapped bulk density, true density, color, compressibility index (CI), Hausner ratio (HR)], and chemical properties [acid detergent fiber (ADF), neutral detergent fiber (NDF), oil, crude protein, starch, ash, etc]. The results of the bench-scale study were also compared with data from a previous plant-scale DDGS production process investigation that used similar drying strategies. Results from the experiments indicated that among all 16 drying strategies, the 10% CDS content and 60% DDGS add-back strategy achieved the least specific power consumption (SPC) while the 40% CDS content and 20% DDGS add-back strategy had the highest SPC. The energy efficiency and drying efficiency of the bench-scale data in both drying stage I and drying stage II presented similar trends as process parameters changed. The highest energy and drying efficiencies were achieved in strategies with 10% CDS content while the lowest were in strategies with 40% CDS content. A comparison of the energy and drying efficiencies for the bench-scale strategies conducted in this study with those of similar plant-scale strategies from a previous study showed a similar trend in the data for drying stage 1, even though the actual numbers were quite different for the two experimental scales. On average, the energy and drying efficiencies for the bench-scale study was 40% less than the corresponding plant-scale strategy. CDS content had the most influence on the energy performance during DDGS drying, while percent DDGS add-back had more impact on the SPC given a constant CDS content level. By comparing both the physical properties, bulk density in particular which relates to logistics, and energy performance data, the drying strategy with 20% CDS and 60% add-back performed the best. Therefore, it is not surprising why this is the strategy used by ICM drying process technology for DDGS. The particle size (dwg) and particle size distribution (PSD) of DDGS varied with the drying strategies; by varying CDS content and percent DDGS add-back. It was determined that the percent DDGS add-back had no effect on either PSD or dgw. Under the same drying strategy, drying stage I always had a higher drying rate than stage II. Also, the drying curves under the same CDS content showed similar shapes. As CDS content increased, the color of DDGS became darker; both DDGS bulk density and tapped bulk density increased. In addition, CI and HR values decreased, ADF and NDF contents decreased and oil and ash contents increased with increased CDS content. Changes in percent DDGS add-back had a negligible effect on the DDGS chemical composition. Overall, the physical and chemical composition analysis of DDGS for both bench-scale and plant-scale studies followed similar trends.

Ethanol or Biodiesel? A Systems-Analysis Decision

ERIC Educational Resources Information Center

Dinan, Frank; Stabler, Tom

2008-01-01

This case study stresses the need to broadly consider an entire system, including all of the energy inputs and outputs involved, to determine the real efficiency of that system. It also asks its student audience to consider the role that scientific input plays in policy decision-making processes. It emphasizes that, despite the importance of this…

Biological conversion assay using Clostridium phytofermentans to estimate plant feedstock quality

PubMed Central

2012-01-01

Background There is currently considerable interest in developing renewable sources of energy. One strategy is the biological conversion of plant biomass to liquid transportation fuel. Several technical hurdles impinge upon the economic feasibility of this strategy, including the development of energy crops amenable to facile deconstruction. Reliable assays to characterize feedstock quality are needed to measure the effects of pre-treatment and processing and of the plant and microbial genetic diversity that influence bioconversion efficiency. Results We used the anaerobic bacterium Clostridium phytofermentans to develop a robust assay for biomass digestibility and conversion to biofuels. The assay utilizes the ability of the microbe to convert biomass directly into ethanol with little or no pre-treatment. Plant samples were added to an anaerobic minimal medium and inoculated with C. phytofermentans, incubated for 3 days, after which the culture supernatant was analyzed for ethanol concentration. The assay detected significant differences in the supernatant ethanol from wild-type sorghum compared with brown midrib sorghum mutants previously shown to be highly digestible. Compositional analysis of the biomass before and after inoculation suggested that differences in xylan metabolism were partly responsible for the differences in ethanol yields. Additionally, we characterized the natural genetic variation for conversion efficiency in Brachypodium distachyon and shrub willow (Salix spp.). Conclusion Our results agree with those from previous studies of lignin mutants using enzymatic saccharification-based approaches. However, the use of C. phytofermentans takes into consideration specific organismal interactions, which will be crucial for simultaneous saccharification fermentation or consolidated bioprocessing. The ability to detect such phenotypic variation facilitates the genetic analysis of mechanisms underlying plant feedstock quality. PMID:22316115

Determination of the efficiency of ethanol oxidation in a proton exchange membrane electrolysis cell

NASA Astrophysics Data System (ADS)

Altarawneh, Rakan M.; Majidi, Pasha; Pickup, Peter G.

2017-05-01

Products and residual ethanol in the anode and cathode exhausts of an ethanol electrolysis cell (EEC) have been analyzed by proton NMR and infrared spectrometry under a variety of operating conditions. This provides a full accounting of the fate of ethanol entering the cell, including the stoichiometry of the ethanol oxidation reaction (i.e. the average number of electrons transferred per ethanol molecule), product distribution and the crossover of ethanol and products through the membrane. The reaction stoichiometry (nav) is the key parameter that determines the faradaic efficiency of both EECs and direct ethanol fuel cells. Values determined independently from the product distribution, amount of ethanol consumed, and a simple electrochemical method based on the dependence of the current on the flow rate of the ethanol solution are compared. It is shown that the electrochemical method yields results that are consistent with those based on the product distribution, and based on the consumption of ethanol when crossover is accounted for. Since quantitative analysis of the cathode exhaust is challenging, the electrochemical method provides a valuable alternative for routine determination of nav, and hence the faradaic efficiency of the cell.

Simultaneous production of 2,3-butanediol, ethanol and hydrogen with a Klebsiella sp. strain isolated from sewage sludge.

PubMed

Wu, Ken-Jer; Saratale, Ganesh D; Lo, Yung-Chung; Chen, Wen-Ming; Tseng, Ze-Jing; Chang, Ming-Ching; Tsai, Ben-Ching; Su, Ay; Chang, Jo-Shu

2008-11-01

A Klebsiella sp. HE1 strain isolated from hydrogen-producing sewage sludge was examined for its ability to produce H2 and other valuable soluble metabolites (e.g., ethanol and 2,3-butanediol) from sucrose-based medium. The effect of pH and carbon substrate concentration on the production of soluble and gaseous products was investigated. The major soluble metabolite produced from Klebsiella sp. HE1 was 2,3-butanediol, accounting for over 42-58% of soluble microbial products (SMP) and its production efficiency enhanced after increasing the initial culture pH to 7.3 (without pH control). The HE1 strain also produced ethanol (contributing to 29-42% of total SMP) and a small amount of lactic acid and acetic acid. The gaseous products consisted of H2 (25-36%) and CO2 (64-75%). The optimal cumulative hydrogen production (2.7 l) and hydrogen yield (0.92mol H2 mol sucrose(-1)) were obtained at an initial sucrose concentration of 30g CODl(-1) (i.e., 26.7gl(-1)), which also led to the highest production rate for H2 (3.26mmol h(-1)l(-1)), ethanol (6.75mmol h(-1)l(-1)) and 2,3-butanediol (7.14mmol h(-1)l(-1)). The highest yield for H2, ethanol and 2,3-butanediol was 0.92, 0.81 and 0.59molmol-sucrose(-1), respectively. As for the overall energy production performance, the highest energy generation rate was 27.7kJ h(-1)l(-1) and the best energy yield was 2.45kJmolsucrose(-1), which was obtained at a sucrose concentration of 30 and 20g CODl(-1), respectively.

Technique of ethanol food grade production with batch distillation and dehydration using starch-based adsorbent

NASA Astrophysics Data System (ADS)

Widjaja, Tri; Altway, Ali; Ni'mah, Hikmatun; Tedji, Namira; Rofiqah, Umi

2015-12-01

Development and innovation of ethanol food grade production are becoming the reasearch priority to increase economy growth. Moreover, the government of Indonesia has established regulation for increasing the renewable energy as primary energy. Sorghum is cerealia plant that contains 11-16% sugar that is optimum for fermentation process, it is potential to be cultivated, especially at barren area in Indonesia. The purpose of this experiment is to learn about the effect of microorganisms in fermentation process. Fermentation process was carried out batchwise in bioreactor and used 150g/L initial sugar concentration. Microorganisms used in this experiment are Zymomonas mobilis mutation (A3), Saccharomyces cerevisiae and mixed of Pichia stipitis. The yield of ethanol can be obtained from this experiment. For ethanol purification result, distillation process from fermentation process has been done to search the best operation condition for efficiency energy consumption. The experiment for purification was divided into two parts, which are distillation with structured packing steel wool and adsorption (dehydration) sequencely. In distillation part, parameters evaluation (HETP and pressure drop) of distillation column that can be used for scale up are needed. The experiment was operated at pressure of 1 atm. The distillation stage was carried out at 85 °C and reflux ratio of 0.92 with variety porosities of 20%, 40%, and 60%. Then the adsorption process was done at 120°C and two types of adsorbent, which are starch - based adsorbent with ingredient of cassava and molecular sieve 3A, were used. The adsorption process was then continued to purify the ethanol from impurities by using activated carbon. This research shows that the batch fermentation process with Zymomonas mobilis A3 obtain higher % yield of ethanol of 40,92%. In addition to that, for purification process, the best operation condition is by using 40% of porosity of stuctured packing steel wool in distillation stage and starch-based adsorbent in adsorption stage, which can obtain ethanol content of 92,15% with acetic acid percentage of 0,001% and the rest is water. This result is qualified for ethanol food grade specification which is between 90 - 94 % of ethanol with maximum percentage of acetic acid is 0,003%, and passes in fusel oil and isopropyl alcohol test.

Engineered yeast with a CO2-fixation pathway to improve the bio-ethanol production from xylose-mixed sugars.

PubMed

Li, Yun-Jie; Wang, Miao-Miao; Chen, Ya-Wei; Wang, Meng; Fan, Li-Hai; Tan, Tian-Wei

2017-03-06

Bio-ethanol production from lignocellulosic raw materials could serve as a sustainable potential for improving the supply of liquid fuels in face of the food-to-fuel competition and the growing energy demand. Xylose is the second abundant sugar of lignocelluloses hydrolysates, but its commercial-scale conversion to ethanol by fermentation is challenged by incomplete and inefficient utilization of xylose. Here, we use a coupled strategy of simultaneous maltose utilization and in-situ carbon dioxide (CO 2 ) fixation to achieve efficient xylose fermentation by the engineered Saccharomyces cerevisiae. Our results showed that the introduction of CO 2 as electron acceptor for nicotinamide adenine dinucleotide (NADH) oxidation increased the total ethanol productivity and yield at the expense of simultaneous maltose and xylose utilization. Our achievements present an innovative strategy using CO 2 to drive and redistribute the central pathways of xylose to desirable products and demonstrate a possible breakthrough in product yield of sugars.

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.

Separation of ethanol/water azeotrope using compound starch-based adsorbents.

PubMed

Wang, Yanhong; Gong, Chunmei; Sun, Jinsheng; Gao, Hong; Zheng, Shuai; Xu, Shimin

2010-08-01

Comparing breakthrough cures of five starch-based materials experimentally prepared for ethanol dehydration, a compound adsorptive agent ZSG-1 was formulated with high adsorption capacity, low energy and material cost. The selective water adsorption was conducted in a fixed-bed absorber packed with ZSG-1 to find the optimum conditions yielding 99.7 wt% anhydrous ethanol with high efficiency. The adsorption kinetics is well described by Bohart-Adams equation. The adsorption heat, Delta H(abs), was calculated to be -3.16 x 10(4)J mol(-1) from retention data by inverse gas chromatography. Results suggested that water entrapment in ZSG-1 is a exothermic and physisorption process. Also, ZSG-1 is recyclable for on-site multiple-use and then adapt for upstream fermentation process after saturation, avoiding pollution through disposal. (c) 2010 Elsevier Ltd. All rights reserved.

Vapor-fed bio-hybrid fuel cell.

PubMed

Benyamin, Marcus S; Jahnke, Justin P; Mackie, David M

2017-01-01

Concentration and purification of ethanol and other biofuels from fermentations are energy-intensive processes, with amplified costs at smaller scales. To circumvent the need for these processes, and to potentially reduce transportation costs as well, we have previously investigated bio-hybrid fuel cells (FCs), in which a fermentation and FC are closely coupled. However, long-term operation requires strictly preventing the fermentation and FC from harming each other. We introduce here the concept of the vapor-fed bio-hybrid FC as a means of continuously extracting power from ongoing fermentations at ambient conditions. By bubbling a carrier gas (N 2 ) through a yeast fermentation and then through a direct ethanol FC, we protect the FC anode from the catalyst poisons in the fermentation (which are non-volatile), and also protect the yeast from harmful FC products (notably acetic acid) and from build-up of ethanol. Since vapor-fed direct ethanol FCs at ambient conditions have never been systematically characterized (in contrast to vapor-fed direct methanol FCs), we first assess the effects on output power and conversion efficiency of ethanol concentration, vapor flow rate, and FC voltage. The results fit a continuous stirred-tank reactor model. Over a wide range of ethanol partial pressures (2-8 mmHg), power densities are comparable to those for liquid-fed direct ethanol FCs at the same temperature, with power densities >2 mW/cm 2 obtained. We then demonstrate the continuous operation of a vapor-fed bio-hybrid FC with fermentation for 5 months, with no indication of performance degradation due to poisoning (of either the FC or the fermentation). It is further shown that the system is stable, recovering quickly from disturbances or from interruptions in maintenance. The vapor-fed bio-hybrid FC enables extraction of power from dilute bio-ethanol streams without costly concentration and purification steps. The concept should be scalable to both large and small operations and should be generalizable to other biofuels and waste-to-energy systems.

Biorefinery process for protein extraction from oriental mustard (Brassica juncea (L.) Czern.) using ethanol stillage.

PubMed

Ratanapariyanuch, Kornsulee; Tyler, Robert T; Shim, Youn Young; Reaney, Martin Jt

2012-01-12

Large volumes of treated process water are required for protein extraction. Evaporation of this water contributes greatly to the energy consumed in enriching protein products. Thin stillage remaining from ethanol production is available in large volumes and may be suitable for extracting protein rich materials. In this work protein was extracted from ground defatted oriental mustard (Brassica juncea (L.) Czern.) meal using thin stillage. Protein extraction efficiency was studied at pHs between 7.6 and 10.4 and salt concentrations between 3.4 × 10-2 and 1.2 M. The optimum extraction efficiency was pH 10.0 and 1.0 M NaCl. Napin and cruciferin were the most prevalent proteins in the isolate. The isolate exhibited high in vitro digestibility (74.9 ± 0.80%) and lysine content (5.2 ± 0.2 g/100 g of protein). No differences in the efficiency of extraction, SDS-PAGE profile, digestibility, lysine availability, or amino acid composition were observed between protein extracted with thin stillage and that extracted with NaCl solution. The use of thin stillage, in lieu of water, for protein extraction would decrease the energy requirements and waste disposal costs of the protein isolation and biofuel production processes.

Biorefinery process for protein extraction from oriental mustard (Brassica juncea (L.) Czern.) using ethanol stillage

PubMed Central

2012-01-01

Large volumes of treated process water are required for protein extraction. Evaporation of this water contributes greatly to the energy consumed in enriching protein products. Thin stillage remaining from ethanol production is available in large volumes and may be suitable for extracting protein rich materials. In this work protein was extracted from ground defatted oriental mustard (Brassica juncea (L.) Czern.) meal using thin stillage. Protein extraction efficiency was studied at pHs between 7.6 and 10.4 and salt concentrations between 3.4 × 10-2 and 1.2 M. The optimum extraction efficiency was pH 10.0 and 1.0 M NaCl. Napin and cruciferin were the most prevalent proteins in the isolate. The isolate exhibited high in vitro digestibility (74.9 ± 0.80%) and lysine content (5.2 ± 0.2 g/100 g of protein). No differences in the efficiency of extraction, SDS-PAGE profile, digestibility, lysine availability, or amino acid composition were observed between protein extracted with thin stillage and that extracted with NaCl solution. The use of thin stillage, in lieu of water, for protein extraction would decrease the energy requirements and waste disposal costs of the protein isolation and biofuel production processes. PMID:22239856

Silica-Titania Composite (STC)'s Performance in the Photocatalytic Oxidation of Polar VOCs

NASA Technical Reports Server (NTRS)

Levine, Lanfang H.; Coutts, Janelle; Richards, Jeffrey; Mazyck, David; Mazyck, David

2011-01-01

The objective of this paper is to determine the performance of a Silica-Titania Composite (STC) in the photocatalytic oxidation (PCO) of polar VOCs for potential applications in trace contaminant control within space habitats such as the ISS and CEV Orion. Tests were carried out in a bench scale STC-packed annular reactor under continuous illumination by either a UV-C germicidal lamp(lambda (sub max) = 254 nm) or UV-A fluorescent BLB (lambda(sub max) = 365 nm) for the removal of ethanol (a predominant polar VOC in the ISS cabin). The STC's performance was evaluated in terms of the ethanol mineralization rate, mineralization efficiency, and the extent of its oxidation intermediate (acetaldehyde) formation in response to the type of light source (photon energy and photon flux) and relative humidity (RH) implemented. Results demonstrated that acetaldehyde was the only quantifiable intermediate in the effluent under UV illumination, but was not found in the dark adsorption experiments. The mineralization rate increased with an increase in photon energy (UV-C greater than UV-A), even though both lamps were adjusted to emit the same incident photon flux, and also increased with increasing photon flux. However, photonic efficiency decreased as the photon flux increased. More importantly, a higher photon flux gave rise to a lower effluent acetaldehyde concentration. The effect of RH on PCO was complex and intriguing because it affected both physical adsorption and photocatalytic oxidation. In general, increasing RH caused a decrease in adsorption capacity for ethanol and reduced the mineralization efficiency with a concomitant higher acetaldehyde evolution rate. The effect of RH was less profound than that of photon flux.

Liquid fuel reforming using microwave plasma at atmospheric pressure

NASA Astrophysics Data System (ADS)

Miotk, Robert; Hrycak, Bartosz; Czylkowski, Dariusz; Dors, Miroslaw; Jasinski, Mariusz; Mizeraczyk, Jerzy

2016-06-01

Hydrogen is expected to be one of the most promising energy carriers. Due to the growing interest in hydrogen production technologies, in this paper we present the results of experimental investigations of thermal decomposition and dry reforming of two alcohols (ethanol and isopropanol) in the waveguide-supplied metal-cylinder-based nozzleless microwave (915 MHz) plasma source (MPS). The hydrogen production experiments were preceded by electrodynamics properties investigations of the used MPS and plasma spectroscopic diagnostics. All experimental tests were performed with the working gas (nitrogen or carbon dioxide) flow rate ranging from 1200 to 3900 normal litres per hour and an absorbed microwave power up to 5 kW. The alcohols were introduced into the plasma using an induction heating vaporizer. The ethanol thermal decomposition resulted in hydrogen selectivity up to 100%. The hydrogen production rate was up to 1150 NL(H2) h-1 and the energy yield was 267 NL(H2) kWh-1 of absorbed microwave energy. Due to intense soot production, the thermal decomposition process was not appropriate for isopropanol conversion. Considering the dry reforming process, using isopropanol was more efficient in hydrogen production than ethanol. The rate and energy yield of hydrogen production were up to 1116 NL(H2) h-1 and 223 NL(H2) kWh-1 of microwave energy used, respectively. However, the hydrogen selectivity was no greater than 37%. Selected results given by the experiment were compared with the results of numerical modeling.

Critical Zone services as environmental assessment criteria in intensively managed landscapes

NASA Astrophysics Data System (ADS)

Richardson, Meredith; Kumar, Praveen

2017-06-01

The Critical Zone (CZ) includes the biophysical processes occurring from the top of the vegetation canopy to the weathering zone below the groundwater table. CZ services provide a measure for the goods and benefits derived from CZ processes. In intensively managed landscapes, cropland is altered through anthropogenic energy inputs to derive more productivity, as agricultural products, than would be possible under natural conditions. However, the actual costs of alterations to CZ functions within landscape profiles are unknown. Through comparisons of corn feed and corn-based ethanol, we show that valuation of these CZ services in monetary terms provides a more concrete tool for characterizing seemingly abstract environmental damages from agricultural production systems. Multiple models are combined to simulate the movement of nutrients throughout the soil system, enabling the measurement of agricultural anthropogenic impacts to the CZ's regulating services. Results indicate water quality and atmospheric stabilizing services, measured by soil carbon storage, carbon respiration, and nitrate leaching, among others, can cost more than double that of emissions estimated in previous studies. Energy efficiency in addition to environmental impact is assessed to demonstrate how the inclusion of CZ services is necessary in accounting for the entire life cycle of agricultural production systems. These results conclude that feed production systems are more energy efficient and less environmentally costly than corn-based ethanol.

The Effect of Photon Source on Heterogeneous Photocatalytic Oxidation of Ethanol by a Silica-Titania Composite

NASA Technical Reports Server (NTRS)

Coutts, Janelle L.; Levine, Lanfang H.; Richards, Jeffrey T.; Mazyck, David W.

2011-01-01

The objective of this study was to distinguish the effect of photon flux (i.e., photons per unit time reaching a surface) from that of photon energy (i.e., wavelength) of a photon source on the silica-titania composite (STC)-catalyzed degradation of ethanol in the gas phase. Experiments were conducted in a bench-scale annular reactor packed with STC pellets and irradiated with either a UV-A fluorescent black light blue lamp ((gamma)max=365 nm) at its maximum light intensity or a UV-C germicidal lamp ((gamma)max=254 nm) at three levels of light intensity. The STC-catalyzed oxidation of ethanol was found to follow zero-order kinetics with respect to CO2 production, regardless of the photon source. Increased photon flux led to increased EtOH removal, mineralization, and oxidation rate accompanied by lower intermediate concentration in the effluent. The oxidation rate was higher in the reactor irradiated by UV-C than by UV-A (38.4 vs. 31.9 nM/s) at the same photon flux, with similar trends for mineralization (53.9 vs. 43.4%) and reaction quantum efficiency (i.e., photonic efficiency, 63.3 vs. 50.1 nmol CO2 (mu)mol/photons). UV-C irradiation also led to decreased intermediate concentration in the effluent . compared to UV-A irradiation. These results demonstrated that STC-catalyzed oxidation is enhanced by both increased photon flux and photon energy.

Bioconversion of dilute-acid pretreated sorghum bagasse to ethanol by Neurospora crassa.

PubMed

Dogaris, Ioannis; Gkounta, Olga; Mamma, Diomi; Kekos, Dimitris

2012-07-01

Bioethanol production from sweet sorghum bagasse (SB), the lignocellulosic solid residue obtained after extraction of sugars from sorghum stalks, can further improve the energy yield of the crop. The aim of the present work was to evaluate a cost-efficient bioconversion of SB to ethanol at high solids loadings (16 % at pretreatment and 8 % at fermentation), low cellulase activities (1-7 FPU/g SB) and co-fermentation of hexoses and pentoses. The fungus Neurospora crassa DSM 1129 was used, which exhibits both depolymerase and co-fermentative ability, as well as mixed cultures with Saccharomyces cerevisiae 2541. A dilute-acid pretreatment (sulfuric acid 2 g/100 g SB; 210 °C; 10 min) was implemented, with high hemicellulose decomposition and low inhibitor formation. The bioconversion efficiency of N. crassa was superior to S. cerevisiae, while their mixed cultures had negative effect on ethanol production. Supplementing the in situ produced N. crassa cellulolytic system (1.0 FPU/g SB) with commercial cellulase and β-glucosidase mixture at low activity (6.0 FPU/g SB) increased ethanol production to 27.6 g/l or 84.7 % of theoretical yield (based on SB cellulose and hemicellulose sugar content). The combined dilute-acid pretreatment and bioconversion led to maximum cellulose and hemicellulose hydrolysis 73.3 % and 89.6 %, respectively.

Optimization of suitable ethanol blend ratio for motorcycle engine using response surface method.

PubMed

Chen, Yu-Liang; Chen, Suming; Tsai, Jin-Ming; Tsai, Chao-Yin; Fang, Hsin-Hsiung; Yang, I-Chang; Liu, Sen-Yuan

2012-01-01

In view of energy shortage and air pollution, ethanol-gasoline blended fuel used for motorcycle engine was studied in this work. The emissions of carbon monoxide (CO), nitrogen oxides (NO(X)) and engine performance of a 125 cc four-stroke motorcycle engine with original carburetor using ethanol-gasoline fuels were investigated. The model of three-variable Box Behnken design (BBD) was used for experimental design, the ethanol blend ratios were prepared at 0, 10, 20 vol%; the speeds of motorcycle were selected as 30, 45, 60 km/h; and the throttle positions were set at 30, 60, 90 %. Both engine performance and air pollutant emissions were then analyzed by response surface method (RSM) to yield optimum operation parameters for tolerable pollutant emissions and maximum engine performance. The RSM optimization analysis indicated that the most suitable ethanol-gasoline blended ratio was found at the range of 3.92-4.12 vol% to yield a comparable fuel conversion efficiency, while considerable reductions of exhaust pollutant emissions of CO (-29 %) and NO(X) (-12 %) when compared to pure gasoline fuel. This study demonstrated low ethanol-gasoline blended fuels could be used in motorcycle carburetor engines without any modification to keep engine power while reducing exhaust pollutants.

Energy efficiency enhancement of ethanol electrooxidation on Pd-CeO(2)/C in passive and active polymer electrolyte-membrane fuel cells.

PubMed

Bambagioni, Valentina; Bianchini, Claudio; Chen, Yanxin; Filippi, Jonathan; Fornasiero, Paolo; Innocenti, Massimo; Lavacchi, Alessandro; Marchionni, Andrea; Oberhauser, Werner; Vizza, Francesco

2012-07-01

Pd nanoparticles have been generated by performing an electroless procedure on a mixed ceria (CeO(2))/carbon black (Vulcan XC-72) support. The resulting material, Pd-CeO(2)/C, has been characterized by means of transmission electron microscopy (TEM), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and X-ray diffraction (XRD) techniques. Electrodes coated with Pd-CeO(2)/C have been scrutinized for the oxidation of ethanol in alkaline media in half cells as well as in passive and active direct ethanol fuel cells (DEFCs). Membrane electrode assemblies have been fabricated using Pd-CeO(2)/C anodes, proprietary Fe-Co cathodes, and Tokuyama anion-exchange membranes. The monoplanar passive and active DEFCs have been fed with aqueous solutions of 10 wt% ethanol and 2 M KOH, supplying power densities as high as 66 mW cm(-2) at 25 °C and 140 mW cm(-2) at 80 °C. A comparison with a standard anode electrocatalyst containing Pd nanoparticles (Pd/C) has shown that, at even metal loading and experimental conditions, the energy released by the cells with the Pd-CeO(2)/C electrocatalyst is twice as much as that supplied by the cells with the Pd/C electrocatalyst. A cyclic voltammetry study has shown that the co-support ceria contributes to the remarkable decrease of the onset oxidation potential of ethanol. It is proposed that ceria promotes the formation at low potentials of species adsorbed on Pd, Pd(I)-OH(ads), that are responsible for ethanol oxidation. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Role of Biofuels Coproducts in Feeding the World Sustainably.

PubMed

Shurson, Gerald C

2017-02-08

One of the grand challenges facing our society today is finding solutions for feeding the world sustainably. The food-versus-fuel debate is a controversy embedded in this challenge, involving the trade-offs of using grains and oilseeds for biofuels production versus animal feed and human food. However, only 6% of total global grain produced is used to produce ethanol. Furthermore, biofuels coproducts contribute to sustainability of food production because only 1% to 2.5% of the overall energy efficiency is lost from converting crops into biofuels and animal feed, and approximately one-third of the corn used to produce ethanol is recovered as feed coproducts. Extensive research has been conducted over the past 15 years on biofuels coproducts to (a) optimize their use for improving caloric and nutritional efficiency in animal feeds, (b) identify benefits and limitations of use in various animal diets, (c) characterize their unique nutraceutical properties, and (d) evaluate their environmental impacts.

Biochemical characterization of ethanol-dependent reduction of furfural by alcohol dehydrogenases.

PubMed

Li, Qunrui; Metthew Lam, L K; Xun, Luying

2011-11-01

Lignocellulosic biomass is usually converted to hydrolysates, which consist of sugars and sugar derivatives, such as furfural. Before yeast ferments sugars to ethanol, it reduces toxic furfural to non-inhibitory furfuryl alcohol in a prolonged lag phase. Bioreduction of furfural may shorten the lag phase. Cupriavidus necator JMP134 rapidly reduces furfural with a Zn-dependent alcohol dehydrogenase (FurX) at the expense of ethanol (Li et al. 2011). The mechanism of the ethanol-dependent reduction of furfural by FurX and three homologous alcohol dehydrogenases was investigated. The reduction consisted of two individual reactions: ethanol-dependent reduction of NAD(+) to NADH and then NADH-dependent reduction of furfural to furfuryl alcohol. The kinetic parameters of the coupled reaction and the individual reactions were determined for the four enzymes. The data indicated that limited NADH was released in the coupled reaction. The enzymes had high affinities for NADH (e.g., K ( d ) of 0.043 μM for the FurX-NADH complex) and relatively low affinities for NAD(+) (e.g., K ( d ) of 87 μM for FurX-NAD(+)). The kinetic data suggest that the four enzymes are efficient "furfural reductases" with either ethanol or NADH as the reducing power. The standard free energy change (ΔG°') for ethanol-dependent reduction of furfural was determined to be -1.1 kJ mol(-1). The physiological benefit for ethanol-dependent reduction of furfural is likely to replace toxic and recalcitrant furfural with less toxic and more biodegradable acetaldehyde.

Genetic improvement of native xylose-fermenting yeasts for ethanol production.

PubMed

Harner, Nicole K; Wen, Xin; Bajwa, Paramjit K; Austin, Glen D; Ho, Chi-Yip; Habash, Marc B; Trevors, Jack T; Lee, Hung

2015-01-01

Lignocellulosic substrates are the largest source of fermentable sugars for bioconversion to fuel ethanol and other valuable compounds. To improve the economics of biomass conversion, it is essential that all sugars in potential hydrolysates be converted efficiently into the desired product(s). While hexoses are fermented into ethanol and some high-value chemicals, the bioconversion of pentoses in hydrolysates remains inefficient. This remains one of the key challenges in lignocellulosic biomass conversion. Native pentose-fermenting yeasts can ferment both glucose and xylose in lignocellulosic biomass to ethanol. However, they perform poorly in the presence of hydrolysate inhibitors, exhibit low ethanol tolerance and glucose repression, and ferment pentoses less efficiently than the main hexoses glucose and mannose. This paper reviews classical and molecular strain improvement strategies applied to native pentose-fermenting yeasts for improved ethanol production from xylose and lignocellulosic substrates. We focus on Pachysolen tannophilus, Scheffersomyces (Candida) shehatae, Scheffersomyces (Pichia) stipitis, and Spathaspora passalidarum which are good ethanol producers among the native xylose-fermenting yeasts. Strains obtained thus far are not robust enough for efficient ethanol production from lignocellulosic hydrolysates and can benefit from further improvements.

Facile synthesis of a platinum-lead oxide nanocomposite catalyst with high activity and durability for ethanol electrooxidation.

PubMed

Yang, Wei-Hua; Wang, Hong-Hui; Chen, De-Hao; Zhou, Zhi-You; Sun, Shi-Gang

2012-12-21

Aimed at searching for highly active and stable nano-scale Pt-based catalysts that can improve significantly the energy conversion efficiency of direct ethanol fuel cells (DEFCs), a novel Pt-PbO(x) nanocomposite (Pt-PbO(x) NC) catalyst with a mean size of 3.23 nm was synthesized through a simple wet chemistry method without using a surfactant, organometallic precursors and high temperature. Electrocatalytic tests demonstrated that the as-prepared Pt-PbO(x) NC catalyst possesses a much higher catalytic activity and a longer durability than Pt nanoparticles (nm-Pt) and commercial Pt black catalysts for ethanol electrooxidation. For instance, Pt-PbO(x) NC showed an onset potential that was 30 mV and 44 mV less positive, together with a peak current density 1.7 and 2.6 times higher than those observed for nm-Pt and Pt black catalysts in the cyclic voltammogram tests. The ratio of current densities per unit Pt mass on Pt-PbO(x) NC, nm-Pt and Pt black catalysts is 27.3 : 3.4 : 1 for the long-term (2 hours) chronoamperometric experiments measured at -0.4 V (vs. SCE). In situ FTIR spectroscopic studies revealed that the activity of breaking C-C bonds of ethanol of the Pt-PbO(x) NC is as high as 5.17 times that of the nm-Pt, which illustrates a high efficiency of ethanol oxidation to CO(2) on the as-prepared Pt-PbO(x) NC catalyst.

Direct conversion of wet algae to crude biodiesel under supercritical ethanol conditions

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

Reddy, Harvind K.; Muppaneni, Tapaswy; Patil, Prafulla D.

This paper presents a single-step, environmentally friendly approach for the direct conversion of wet algae to crude biodiesel under supercritical ethanol conditions. Ethanol was used for the simultaneous extraction and transesterification of lipids in algae to produce fatty acid ethyl esters at supercritical conditions. In this work the effects of process parameters dry algae to ethanol (wt./vol.) ratio (1:6-1:15), reaction temperature (245-270 C), and reaction time (2-30 min.) on the yield of fatty acid ethyl esters (FAEE) were studied. 67% conversion was achieved at 265 C and 20 min of reaction time. The calorific value of a purified biodiesel samplemore » produced at optimum conditions was measured to be 43 MJ/kg, which is higher than that of fatty acid methyl esters produced from the same biomass. The purified fatty acid ethyl esters were analyzed using GC-MS and FTIR. TGA analysis of algal biomass and purified FAEE was presented along with TEM images of the biomass captured before and after supercritical ethanol transesterification. This green conversion process has the potential to provide an energy-efficient and economical route for the production of renewable biodiesel production.« less

Thermochemical recovery of heat contained in flue gases by means of bioethanol conversion

NASA Astrophysics Data System (ADS)

Pashchenko, D. I.

2013-06-01

In the present paper consideration is being given to the use of bioethanol in the schemes of thermochemical recovery of heat contained in exit flue gases. Schematic diagrams illustrate the realization of thermochemical heat recovery by implementing ethanol steam conversion and conversion of ethanol by means of products of its complete combustion. The feasibility of attaining a high degree of recovery of heat contained in flue gases at the moderate temperature (up to 450°C) of combustion components is demonstrated in the example of the energy balance of the system for thermochemical heat recovery. The simplified thermodynamic analysis of the process of ethanol steam conversion was carried out in order to determine possible ranges of variation of process variables (temperature, pressure, composition) of a reaction mixture providing the efficient heat utilization. It was found that at the temperature above 600 K the degree of ethanol conversion is near unity. The equilibrium composition of products of reaction of ethanol steam conversion has been identified for different temperatures at which the process occurs at the ratio H2O/EtOH = 1 and at the pressure of 0.1 MPa. The obtained results of calculation agree well with the experimental data.

Microbial‐based motor fuels: science and technology

PubMed Central

Wackett, Lawrence P.

2008-01-01

Summary The production of biofuels via microbial biotechnology is a very active field of research. A range of fuel molecule types are currently under consideration: alcohols, ethers, esters, isoprenes, alkenes and alkanes. At the present, the major alcohol biofuel is ethanol. The ethanol fermentation is an old technology. Ongoing efforts aim to increase yield and energy efficiency of ethanol production from biomass. n‐Butanol, another microbial fermentation product, is potentially superior to ethanol as a fuel but suffers from low yield and unwanted side‐products currently. In general, biodiesel fuels consist of fatty acid methyl esters in which the carbon derives from plants, not microbes. A new biodiesel product, called microdiesel, can be generated in engineered bacterial cells that condense ethanol with fatty acids. Perhaps the best fuel type to generate from biomass would be biohydrocarbons. Microbes are known to produce hydrocarbons such as isoprenes, long‐chain alkenes and alkanes. The biochemical mechanisms of microbial hydrocarbon biosynthesis are currently under study. Hydrocarbons and minimally oxygenated molecules may also be produced by hybrid chemical and biological processes. A broad interest in novel fuel molecules is also driving the development of new bioinformatics tools to facilitate biofuels research. PMID:21261841

Maximizing cellulosic ethanol potentials by minimizing wastewater generation and energy consumption: Competing with corn ethanol.

PubMed

Liu, Gang; Bao, Jie

2017-12-01

Energy consumption and wastewater generation in cellulosic ethanol production are among the determinant factors on overall cost and technology penetration into fuel ethanol industry. This study analyzed the energy consumption and wastewater generation by the new biorefining process technology, dry acid pretreatment and biodetoxification (DryPB), as well as by the current mainstream technologies. DryPB minimizes the steam consumption to 8.63GJ and wastewater generation to 7.71tons in the core steps of biorefining process for production of one metric ton of ethanol, close to 7.83GJ and 8.33tons in corn ethanol production, respectively. The relatively higher electricity consumption is compensated by large electricity surplus from lignin residue combustion. The minimum ethanol selling price (MESP) by DryPB is below $2/gal and falls into the range of corn ethanol production cost. The work indicates that the technical and economical gap between cellulosic ethanol and corn ethanol has been almost filled up. Copyright © 2017 Elsevier Ltd. All rights reserved.

Machine Learning of Accurate Energy-Conserving Molecular Force Fields

NASA Astrophysics Data System (ADS)

Chmiela, Stefan; Tkatchenko, Alexandre; Sauceda, Huziel; Poltavsky, Igor; Schütt, Kristof; Müller, Klaus-Robert; GDML Collaboration

Efficient and accurate access to the Born-Oppenheimer potential energy surface (PES) is essential for long time scale molecular dynamics (MD) simulations. Using conservation of energy - a fundamental property of closed classical and quantum mechanical systems - we develop an efficient gradient-domain machine learning (GDML) approach to construct accurate molecular force fields using a restricted number of samples from ab initio MD trajectories (AIMD). The GDML implementation is able to reproduce global potential-energy surfaces of intermediate-size molecules with an accuracy of 0.3 kcal/mol for energies and 1 kcal/mol/Å for atomic forces using only 1000 conformational geometries for training. We demonstrate this accuracy for AIMD trajectories of molecules, including benzene, toluene, naphthalene, malonaldehyde, ethanol, uracil, and aspirin. The challenge of constructing conservative force fields is accomplished in our work by learning in a Hilbert space of vector-valued functions that obey the law of energy conservation. The GDML approach enables quantitative MD simulations for molecules at a fraction of cost of explicit AIMD calculations, thereby allowing the construction of efficient force fields with the accuracy and transferability of high-level ab initio methods.

Fumigation of Alcohol in a Light Duty Automotive Diesel Engine

NASA Technical Reports Server (NTRS)

Broukhiyan, E. M. H.; Lestz, S. S.

1981-01-01

A light-duty automotive Diesel engine was fumigated with methanol in amounts up to 35% and 50% of the total fuel energy respectively in order to determine the effect of alcohol fumigation on engine performance at various operating conditons. Engine fuel efficiency, emissions, smoke, and the occurrence of severe knock were the parameters used to evaluate performance. Raw exhaust particulate and its soluble organic extract were screened for biological activity using the Ames Salmonella typhimurium assay. Results are given for a test matrix made up of twelve steady-state operating conditions. For all conditions except the 1/4 rack (light load) condition, modest thermal efficiency gains were noted upon ethanol fumigation. Methanol showed the same increase at 3/4 and full rack (high load) conditions. However, engine roughness or the occurrence of severe knock limited the maximum amount of alcohol that could be fumigated. Brake specific nitrogen oxide concentrations were found to decrease for all ethanol conditions tested. Oxides of nitrogen emissions, on a volume basis, decreased for all alcohol conditions tested. Based on the limited particulate data analyzed, it appears that ethanol fumigation, like methanol fumigation, while lowering the mass of particulated emitted, does enhance the biological activity of that particulate.

Pretreatment on Miscanthus lutarioriparious by liquid hot water for efficient ethanol production

PubMed Central

2013-01-01

Background The C4 perennial grass Miscanthus giganteus has proved to be a promising bio-energy crop. However, the biomass recalcitrance is a major challenge in biofuel production. Effective pretreatment is necessary for achieving a high efficiency in converting the crop to fermentable sugars, and subsequently biofuels and other valued products. Results Miscanthus lutarioriparious was pretreated with a liquid hot water (LHW) reactor. Between the pretreatment severity (PS) of 2.56-4.71, the solid recovery was reduced; cellulose recovery remained nearly unchanged; and the Klason lignin content was slightly increased which was mainly due to the dissolving of hemicellulose and the production of a small amount of pseudo-lignin. The result shows that a LHW PS of 4.71 could completely degrade the hemicellulose in Miscanthus. Hemicellulose removal dislodged the enzymatic barrier of cellulose, and the ethanol conversion of 98.27% was obtained. Conclusions Our study demonstrated that LHW served as an effective pretreatment in case that Miscanthus lutarioriparious was used for ethanol production by simultaneous saccharification and fermentation. The combination and the pretreatment method of Miscanthus feedstock holds a great potential for biofuel production. PMID:23663476

Nebraska Governor, Energy Company Chiefs to See Latest in Renewable Energy

Science.gov Websites

developments in wind, ethanol, solar and building technologies at the U.S. Department of Energy's National the latest in wind technology, " Nelson said. "The lab also is pioneering ethanol production ethanol production." The governor said the U.S. Department of Energy agreed to provide $25,000 to pay

Fabrication of Te@Au core-shell hybrids for efficient ethanol oxidation

NASA Astrophysics Data System (ADS)

Jin, Huile; Wang, Demeng; Zhao, Yuewu; Zhou, Huan; Wang, Shun; Wang, Jichang

2012-10-01

Using Au nanoparticles to catalyze the oxidation of alcohols has garnered increasing attention due to its potential application in direct alcohol fuel cells. In this research Te@Au core-shell hybrids were fabricated for the catalytic oxidation of ethanol, where the preparation procedure involved the initial production of Te crystals with different microstructures and the subsequent utilization of the Te crystal as a template and reducing agent for the production of Te@Au hybrids. The as-prepared core-shell hybrids were characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction techniques. Electrochemical measurements illustrate that the hybrids have great electrocatalytic activity and stability toward ethanol oxidation in alkaline media. The enhanced electrocatalytic property may be attributed to the cooperative effects between the metal and semiconductor and the presence of a large number of active sites on the hybrids surface.

The Effect of Surface Site Ensembles on the Activity and Selectivity of Ethanol Electrooxidation by Octahedral PtNiRh Nanoparticles.

PubMed

Erini, Nina; Beermann, Vera; Gocyla, Martin; Gliech, Manuel; Heggen, Marc; Dunin-Borkowski, Rafal E; Strasser, Peter

2017-06-01

Direct ethanol fuel cells are attractive power sources based on a biorenewable, high energy-density fuel. Their efficiency is limited by the lack of active anode materials which catalyze the breaking of the C-C bond coupled to the 12-electron oxidation to CO 2 . We report shape-controlled PtNiRh octahedral ethanol oxidation electrocatalysts with excellent activity and previously unachieved low onset potentials as low as 0.1 V vs. RHE, while being highly selective to complete oxidation to CO 2 . Our comprehensive characterization and in situ electrochemical ATR studies suggest that the formation of a ternary surface site ensemble around the octahedral Pt 3 Ni 1 Rh x nanoparticles plays a crucial mechanistic role for this behavior. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

One step electrochemical synthesis of bimetallic PdAu supported on nafion–graphene ribbon film for ethanol electrooxidation

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

Shendage, Suresh S., E-mail: sureshsshendage@gmail.com; Singh, Abilash S.; Nagarkar, Jayashree M., E-mail: jm.nagarkar@ictmumbai.edu.in

2015-10-15

Highlights: • Electrochemical deposition of bimetallic PdAu NPs. • Highly loaded PdAu NPs are obtained. • Nafion–graphene supported PdAu NPs shows good activity for ethanol electrooxidation. - Abstract: A nafion–graphene ribbon (Nf–GR) supported bimetallic PdAu nanoparticles (PdAu/Nf–GR) catalyst was prepared by electrochemical codeposition of Pd and Au at constant potential. The prepared catalyst was characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD). The average particle size of PdAu nanoparticles (NPs) determined from XRD was 3.5 nm. The electrocatalytic activity of the PdAu/Nf–GR catalyst was examined by cyclic voltametry.more » It was observed that the as prepared catalyst showed efficient activity and good stability for ethanol electrooxidation in alkaline medium.« less

Technical Support to SBIR Phase II Project: Improved Conversion of Cellulose Waste to Ethanol Using a Dual Bioreactor System: Cooperative Research and Development Final Report, CRADA Number CRD-08-310

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

Zhang, M.

2013-04-01

Over-dependence on fossil fuel has spurred research on alternative energy. Inedible plant materials such as grass and corn stover represent abundant renewable natural resources that can be transformed into biofuel. Problems in enzymatic conversion of biomass to sugars include the use of incomplete synergistic enzymes, end-product inhibition, and adsorption and loss of enzymes necessitating their use in large quantities. Technova Corporation will develop a defined consortium of natural microorganisms that will efficiently break down biomass to energy-rich soluble sugars, and convert them to cleaner-burning ethanol fuel. The project will also develop a novel biocatalytic hybrid reactor system dedicated to thismore » bioprocess, which embodies recent advances in nanotechnology. NREL will participate to develop a continuous fermentation process.« less

Overcoming the energetic limitations of syngas fermentation.

PubMed

Molitor, Bastian; Marcellin, Esteban; Angenent, Largus T

2017-12-01

The fermentation of synthesis gas (including carbon monoxide, carbon dioxide, and hydrogen) with anaerobic acetogens is an established biotechnological process that has recently been transferred to a commercial scale. The natural product spectrum of acetogens is natively restricted to acetate, ethanol, and 2,3-butanediol but is rapidly expanding to heterologous products. Syngas fermentation can achieve high carbon-efficiencies; however, the underlying metabolism is operating at a thermodynamic limit. This necessitates special enzymatic properties for energy conservation by acetogens. Therefore, the availability of cellular energy is considered to restrain the efficient production of energy-intense products with complex production pathways. The optimization of the feed-gas composition and other process parameters, genetic engineering, and integration with other biotechnologies is required to overcome this limitation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Production of hydrogen, ethanol and volatile fatty acids from the seaweed carbohydrate mannitol.

PubMed

Xia, Ao; Jacob, Amita; Herrmann, Christiane; Tabassum, Muhammad Rizwan; Murphy, Jerry D

2015-10-01

Fermentative hydrogen from seaweed is a potential biofuel of the future. Mannitol, which is a typical carbohydrate component of seaweed, was used as a substrate for hydrogen fermentation. The theoretical specific hydrogen yield (SHY) of mannitol was calculated as 5 mol H2/mol mannitol (615.4 mL H2/g mannitol) for acetic acid pathway, 3 mol H2/mol mannitol (369.2 mL H2/g mannitol) for butyric acid pathway and 1 mol H2/mol mannitol (123.1 mL H2/g mannitol) for lactic acid and ethanol pathways. An optimal SHY of 1.82 mol H2/mol mannitol (224.2 mL H2/g mannitol) was obtained by heat pre-treated anaerobic digestion sludge under an initial pH of 8.0, NH4Cl concentration of 25 mM, NaCl concentration of 50mM and mannitol concentration of 10 g/L. The overall energy conversion efficiency achieved was 96.1%. The energy was contained in the end products, hydrogen (17.2%), butyric acid (38.3%) and ethanol (34.2%). Copyright © 2015 Elsevier Ltd. All rights reserved.

Spectroscopic investigation into the design of solid-acid catalysts for the low temperature dehydration of ethanol.

PubMed

Potter, Matthew E; Aswegen, Sivan V; Gibson, Emma K; Silverwood, Ian P; Raja, Robert

2016-07-14

The increased demand for bulk hydrocarbons necessitates research into increasingly sustainable, energy-efficient catalytic processes. Owing to intricately designed structure-property correlations, SAPO-34 has become established as a promising material for the low temperature ethanol dehydration to produce ethylene. However, further optimization of this process requires a precise knowledge of the reaction mechanism at a molecular level. In order to achieve this a range of spectroscopic characterization techniques are required to probe both the interaction with the active site, and also the wider role of the framework. To this end we employ a combination of in situ infra-red and neutron scattering techniques to elucidate the influence of the surface ethoxy species in the activation of both diethyl ether and ethanol, towards the improved formation of ethylene at low temperatures. The combined conclusions of these studies is that the formation of ethylene is the rate determining step, which is of fundamental importance towards the development of this process and the introduction of bio-ethanol as a viable feedstock for ethylene production.

Techno-Economic Analysis of the Deacetylation and Disk Refining Process. Characterizing the Effect of Refining Energy and Enzyme Usage on Minimum Sugar Selling Price and Minimum Ethanol Selling Price

DOE PAGES

Chen, Xiaowen; Shekiro, Joseph; Pschorn, Thomas; ...

2015-10-29

A novel, highly efficient deacetylation and disk refining (DDR) process to liberate fermentable sugars from biomass was recently developed at the National Renewable Energy Laboratory (NREL). The DDR process consists of a mild, dilute alkaline deacetylation step followed by low-energy-consumption disk refining. The DDR corn stover substrates achieved high process sugar conversion yields, at low to modest enzyme loadings, and also produced high sugar concentration syrups at high initial insoluble solid loadings. The sugar syrups derived from corn stover are highly fermentable due to low concentrations of fermentation inhibitors. The objective of this work is to evaluate the economic feasibilitymore » of the DDR process through a techno-economic analysis (TEA). A large array of experiments designed using a response surface methodology was carried out to investigate the two major cost-driven operational parameters of the novel DDR process: refining energy and enzyme loadings. The boundary conditions for refining energy (128–468 kWh/ODMT), cellulase (Novozyme’s CTec3) loading (11.6–28.4 mg total protein/g of cellulose), and hemicellulase (Novozyme’s HTec3) loading (0–5 mg total protein/g of cellulose) were chosen to cover the most commercially practical operating conditions. The sugar and ethanol yields were modeled with good adequacy, showing a positive linear correlation between those yields and refining energy and enzyme loadings. The ethanol yields ranged from 77 to 89 gallons/ODMT of corn stover. The minimum sugar selling price (MSSP) ranged from $0.191 to $0.212 per lb of 50 % concentrated monomeric sugars, while the minimum ethanol selling price (MESP) ranged from $2.24 to $2.54 per gallon of ethanol. The DDR process concept is evaluated for economic feasibility through TEA. The MSSP and MESP of the DDR process falls within a range similar to that found with the deacetylation/dilute acid pretreatment process modeled in NREL’s 2011 design report. The DDR process is a much simpler process that requires less capital and maintenance costs when compared to conventional chemical pretreatments with pressure vessels. As a result, we feel the DDR process should be considered as an option for future biorefineries with great potential to be more cost-effective.« less

Techno-Economic Analysis of the Deacetylation and Disk Refining Process. Characterizing the Effect of Refining Energy and Enzyme Usage on Minimum Sugar Selling Price and Minimum Ethanol Selling Price

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

Chen, Xiaowen; Shekiro, Joseph; Pschorn, Thomas

A novel, highly efficient deacetylation and disk refining (DDR) process to liberate fermentable sugars from biomass was recently developed at the National Renewable Energy Laboratory (NREL). The DDR process consists of a mild, dilute alkaline deacetylation step followed by low-energy-consumption disk refining. The DDR corn stover substrates achieved high process sugar conversion yields, at low to modest enzyme loadings, and also produced high sugar concentration syrups at high initial insoluble solid loadings. The sugar syrups derived from corn stover are highly fermentable due to low concentrations of fermentation inhibitors. The objective of this work is to evaluate the economic feasibilitymore » of the DDR process through a techno-economic analysis (TEA). A large array of experiments designed using a response surface methodology was carried out to investigate the two major cost-driven operational parameters of the novel DDR process: refining energy and enzyme loadings. The boundary conditions for refining energy (128–468 kWh/ODMT), cellulase (Novozyme’s CTec3) loading (11.6–28.4 mg total protein/g of cellulose), and hemicellulase (Novozyme’s HTec3) loading (0–5 mg total protein/g of cellulose) were chosen to cover the most commercially practical operating conditions. The sugar and ethanol yields were modeled with good adequacy, showing a positive linear correlation between those yields and refining energy and enzyme loadings. The ethanol yields ranged from 77 to 89 gallons/ODMT of corn stover. The minimum sugar selling price (MSSP) ranged from $0.191 to $0.212 per lb of 50 % concentrated monomeric sugars, while the minimum ethanol selling price (MESP) ranged from $2.24 to $2.54 per gallon of ethanol. The DDR process concept is evaluated for economic feasibility through TEA. The MSSP and MESP of the DDR process falls within a range similar to that found with the deacetylation/dilute acid pretreatment process modeled in NREL’s 2011 design report. The DDR process is a much simpler process that requires less capital and maintenance costs when compared to conventional chemical pretreatments with pressure vessels. As a result, we feel the DDR process should be considered as an option for future biorefineries with great potential to be more cost-effective.« less

Techno-economic analysis of the deacetylation and disk refining process: characterizing the effect of refining energy and enzyme usage on minimum sugar selling price and minimum ethanol selling price.

PubMed

Chen, Xiaowen; Shekiro, Joseph; Pschorn, Thomas; Sabourin, Marc; Tucker, Melvin P; Tao, Ling

2015-01-01

A novel, highly efficient deacetylation and disk refining (DDR) process to liberate fermentable sugars from biomass was recently developed at the National Renewable Energy Laboratory (NREL). The DDR process consists of a mild, dilute alkaline deacetylation step followed by low-energy-consumption disk refining. The DDR corn stover substrates achieved high process sugar conversion yields, at low to modest enzyme loadings, and also produced high sugar concentration syrups at high initial insoluble solid loadings. The sugar syrups derived from corn stover are highly fermentable due to low concentrations of fermentation inhibitors. The objective of this work is to evaluate the economic feasibility of the DDR process through a techno-economic analysis (TEA). A large array of experiments designed using a response surface methodology was carried out to investigate the two major cost-driven operational parameters of the novel DDR process: refining energy and enzyme loadings. The boundary conditions for refining energy (128-468 kWh/ODMT), cellulase (Novozyme's CTec3) loading (11.6-28.4 mg total protein/g of cellulose), and hemicellulase (Novozyme's HTec3) loading (0-5 mg total protein/g of cellulose) were chosen to cover the most commercially practical operating conditions. The sugar and ethanol yields were modeled with good adequacy, showing a positive linear correlation between those yields and refining energy and enzyme loadings. The ethanol yields ranged from 77 to 89 gallons/ODMT of corn stover. The minimum sugar selling price (MSSP) ranged from $0.191 to $0.212 per lb of 50 % concentrated monomeric sugars, while the minimum ethanol selling price (MESP) ranged from $2.24 to $2.54 per gallon of ethanol. The DDR process concept is evaluated for economic feasibility through TEA. The MSSP and MESP of the DDR process falls within a range similar to that found with the deacetylation/dilute acid pretreatment process modeled in NREL's 2011 design report. The DDR process is a much simpler process that requires less capital and maintenance costs when compared to conventional chemical pretreatments with pressure vessels. As a result, we feel the DDR process should be considered as an option for future biorefineries with great potential to be more cost-effective.

Modeling energy production of solar thermal systems and wind turbines for installation at corn ethanol plants

NASA Astrophysics Data System (ADS)

Ehrke, Elizabeth

Nearly every aspect of human existence relies on energy in some way. Most of this energy is currently derived from fossil fuel resources. Increasing energy demands coupled with environmental and national security concerns have facilitated the move towards renewable energy sources. Biofuels like corn ethanol are one of the ways the U.S. has significantly reduced petroleum consumption. However, the large energy requirement of corn ethanol limits the net benefit of the fuel. Using renewable energy sources to produce ethanol can greatly improve its economic and environmental benefits. The main purpose of this study was to model the useful energy received from a solar thermal array and a wind turbine at various locations to determine the feasibility of applying these technologies at ethanol plants around the country. The model calculates thermal energy received from a solar collector array and electricity generated by a wind turbine utilizing various input data to characterize the equipment. Project cost and energy rate inputs are used to evaluate the profitability of the solar array or wind turbine. The current state of the wind and solar markets were examined to give an accurate representation of the economics of each industry. Eighteen ethanol plant locations were evaluated for the viability of a solar thermal array and/or wind turbine. All ethanol plant locations have long payback periods for solar thermal arrays, but high natural gas prices significantly reduce this timeframe. Government incentives will be necessary for the economic feasibility of solar thermal arrays. Wind turbines can be very profitable for ethanol plants in the Midwest due to large wind resources. The profitability of wind power is sensitive to regional energy prices. However, government incentives for wind power do not significantly change the economic feasibility of a wind turbine. This model can be used by current or future ethanol facilities to investigate or begin the planning process for a solar thermal array or wind turbine. The model is meant to aide in the planning stages of a renewable energy project, and advanced investigation will be needed to move forward with that project.

Microwave-assisted synthesis of palladium nanoparticles intercalated nitrogen doped reduced graphene oxide and their electrocatalytic activity for direct-ethanol fuel cells.

PubMed

Kumar, Rajesh; da Silva, Everson T S G; Singh, Rajesh K; Savu, Raluca; Alaferdov, Andrei V; Fonseca, Leandro C; Carossi, Lory C; Singh, Arvind; Khandka, Sarita; Kar, Kamal K; Alves, Oswaldo L; Kubota, Lauro T; Moshkalev, Stanislav A

2018-04-01

Palladium nanoparticles decorated reduced graphene oxide (Pd-rGO) and palladium nanoparticles intercalated inside nitrogen doped reduced graphene oxide (Pd-NrGO) hybrids have been synthesized by applying a very simple, fast and economic route using microwave-assisted in-situ reduction and exfoliation method. The Pd-NrGO hybrids materials show good activity as catalyst for ethanol electro oxidation for direct ethanol fuel cells (DEFCs) as compared to Pd-rGO hybrids. The enhanced direct ethanol fuel cell can serve as alternative to fossil fuels because it is renewable and environmentally-friendly with a high energy conversion efficiency and low pollutant emission. As proof of concept, the electrocatalytic activity of Pd-NrGO hybrid material was accessed by cyclic voltammetry in presence of ethanol to evaluate its applicability in direct-ethanol fuel cells (DEFCs). The Pd-NrGO catalyst presented higher electro active surface area (∼6.3 m 2  g -1 ) for ethanol electro-oxidation when compared to Pd-rGO hybrids (∼3.7 m 2  g -1 ). Despite the smaller catalytic activity of Pd-NrGO, which was attributed to the lower exfoliation rate of this material in relation to the Pd-rGO, Pd-NrGO showed to be very promising and its catalytic activity can be further improved by tuning the synthesis parameters to increase the exfoliation rate. Copyright © 2018 Elsevier Inc. All rights reserved.

Fuel miles and the blend wall: costs and emissions from ethanol distribution in the United States.

PubMed

Strogen, Bret; Horvath, Arpad; McKone, Thomas E

2012-05-15

From 1991 to 2009, U.S. production of ethanol increased 10-fold, largely due to government programs motivated by climate change, energy security, and economic development goals. As low-level ethanol-gasoline blends have not consistently outperformed ethanol-free gasoline in vehicle performance or tailpipe emissions, national-level economic and environmental goals could be accomplished more efficiently by concentrating consumption of gasoline containing 10% ethanol (i.e., E10) near producers to minimize freight activity. As the domestic transportation of ethanol increased 10-fold in metric ton-kilometers (t-km) from 2000 to 2009, the portion of t-km potentially justified by the E10 blend wall increased from less than 40% to 80%. However, we estimate 10 billion t-km took place annually from 2004 to 2009 for reasons other than the blend wall. This "unnecessary" transportation resulted in more than $240 million in freight costs, 90 million L of diesel consumption, 300,000 metric tons of CO(2)-e emissions, and 440 g of human intake of PM(2.5). By 2009, the marginal savings from enabling Iowa to surpass E10 would have exceeded 2.5 g CO(2)-e/MJ and $0.12/gallon of ethanol, as the next-closest customer was 1600 km away. The use of a national network model enables estimation of marginal transportation impacts from subnational policies, and benefits from policies encouraging concentrated consumption of renewable fuels.

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.

Metabolic engineering of Escherichia coli for ethanol production without foreign genes

NASA Astrophysics Data System (ADS)

Kim, Youngnyun

Worldwide dependence on finite petroleum-based energy necessitates alternative energy sources that can be produced from renewable resources. A successful example of an alternative transportation fuel is bioethanol, produced by microorganisms, from corn starch that is blended with gasoline. However, corn, currently the main feedstock for bioethanol production, also occupies a significant role in human food and animal feed chains. As more corn is diverted to bioethanol, the cost of corn is expected to increase with an increase in the price of food, feed and ethanol. Using lignocellulosic biomass for ethanol production is considered to resolve this problem. However, this requires a microbial biocatalyst that can ferment hexoses and pentoses to ethanol. Escherichia coli is an efficient biocatalyst that can use all the monomeric sugars in lignocellulose, and recombinant derivatives of E. coli have been engineered to produce ethanol as the major fermentation product. In my study, ethanologenic E. coli strains were isolated from a ldhA-, pflB- derivative without introduction of foreign genes. These isolates grew anaerobically and produced ethanol as the main fermentation product. The mutation responsible for anaerobic growth and ethanol production was mapped in the lpdA gene and the mutation was identified as E354K in three of the isolates tested. Another three isolates carried an lpdA mutation, H352Y. Enzyme kinetic studies revealed that the mutated form of the dihydrolipoamide dehydrogenase (LPD) encoded by the lpdA was significantly less sensitive to NADH inhibition than the native LPD. This reduced NADH sensitivity of the mutated LPD was translated into lower sensitivity to NADH of the pyruvate dehydrogenase complex in strain SE2378. The net yield of 4 moles of NADH and 2 moles of acetyl-CoA per mole of glucose produced by a combination of glycolysis and PDH provided a logical basis to explain the production of 2 moles of ethanol per glucose. The development of E. coli provides a potential biocatalyst for conversion of pentoses derived from cellulosic biomass to biobased products without the introduction of new genes.

Life-cycle energy use and greenhouse gas emissions of production of bioethanol from sorghum in the United States.

PubMed

Cai, Hao; Dunn, Jennifer B; Wang, Zhichao; Han, Jeongwoo; Wang, Michael Q

2013-10-02

The availability of feedstock options is a key to meeting the volumetric requirement of 136.3 billion liters of renewable fuels per year beginning in 2022, as required in the US 2007 Energy Independence and Security Act. Life-cycle greenhouse gas (GHG) emissions of sorghum-based ethanol need to be assessed for sorghum to play a role in meeting that requirement. Multiple sorghum-based ethanol production pathways show diverse well-to-wheels (WTW) energy use and GHG emissions due to differences in energy use and fertilizer use intensity associated with sorghum growth and differences in the ethanol conversion processes. All sorghum-based ethanol pathways can achieve significant fossil energy savings. Relative to GHG emissions from conventional gasoline, grain sorghum-based ethanol can reduce WTW GHG emissions by 35% or 23%, respectively, when wet or dried distillers grains with solubles (DGS) is the co-product and fossil natural gas (FNG) is consumed as the process fuel. The reduction increased to 56% or 55%, respectively, for wet or dried DGS co-production when renewable natural gas (RNG) from anaerobic digestion of animal waste is used as the process fuel. These results do not include land-use change (LUC) GHG emissions, which we take as negligible. If LUC GHG emissions for grain sorghum ethanol as estimated by the US Environmental Protection Agency (EPA) are included (26 g CO2e/MJ), these reductions when wet DGS is co-produced decrease to 7% or 29% when FNG or RNG is used as the process fuel. Sweet sorghum-based ethanol can reduce GHG emissions by 71% or 72% without or with use of co-produced vinasse as farm fertilizer, respectively, in ethanol plants using only sugar juice to produce ethanol. If both sugar and cellulosic bagasse were used in the future for ethanol production, an ethanol plant with a combined heat and power (CHP) system that supplies all process energy can achieve a GHG emission reduction of 70% or 72%, respectively, without or with vinasse fertigation. Forage sorghum-based ethanol can achieve a 49% WTW GHG emission reduction when ethanol plants meet process energy demands with CHP. In the case of forage sorghum and an integrated sweet sorghum pathway, the use of a portion of feedstock to fuel CHP systems significantly reduces fossil fuel consumption and GHG emissions. This study provides new insight into life-cycle energy use and GHG emissions of multiple sorghum-based ethanol production pathways in the US. Our results show that adding sorghum feedstocks to the existing options for ethanol production could help in meeting the requirements for volumes of renewable, advanced and cellulosic bioethanol production in the US required by the EPA's Renewable Fuel Standard program.

Life-cycle energy use and greenhouse gas emissions of production of bioethanol from sorghum in the United States

PubMed Central

2013-01-01

Background The availability of feedstock options is a key to meeting the volumetric requirement of 136.3 billion liters of renewable fuels per year beginning in 2022, as required in the US 2007 Energy Independence and Security Act. Life-cycle greenhouse gas (GHG) emissions of sorghum-based ethanol need to be assessed for sorghum to play a role in meeting that requirement. Results Multiple sorghum-based ethanol production pathways show diverse well-to-wheels (WTW) energy use and GHG emissions due to differences in energy use and fertilizer use intensity associated with sorghum growth and differences in the ethanol conversion processes. All sorghum-based ethanol pathways can achieve significant fossil energy savings. Relative to GHG emissions from conventional gasoline, grain sorghum-based ethanol can reduce WTW GHG emissions by 35% or 23%, respectively, when wet or dried distillers grains with solubles (DGS) is the co-product and fossil natural gas (FNG) is consumed as the process fuel. The reduction increased to 56% or 55%, respectively, for wet or dried DGS co-production when renewable natural gas (RNG) from anaerobic digestion of animal waste is used as the process fuel. These results do not include land-use change (LUC) GHG emissions, which we take as negligible. If LUC GHG emissions for grain sorghum ethanol as estimated by the US Environmental Protection Agency (EPA) are included (26 g CO2e/MJ), these reductions when wet DGS is co-produced decrease to 7% or 29% when FNG or RNG is used as the process fuel. Sweet sorghum-based ethanol can reduce GHG emissions by 71% or 72% without or with use of co-produced vinasse as farm fertilizer, respectively, in ethanol plants using only sugar juice to produce ethanol. If both sugar and cellulosic bagasse were used in the future for ethanol production, an ethanol plant with a combined heat and power (CHP) system that supplies all process energy can achieve a GHG emission reduction of 70% or 72%, respectively, without or with vinasse fertigation. Forage sorghum-based ethanol can achieve a 49% WTW GHG emission reduction when ethanol plants meet process energy demands with CHP. In the case of forage sorghum and an integrated sweet sorghum pathway, the use of a portion of feedstock to fuel CHP systems significantly reduces fossil fuel consumption and GHG emissions. Conclusions This study provides new insight into life-cycle energy use and GHG emissions of multiple sorghum-based ethanol production pathways in the US. Our results show that adding sorghum feedstocks to the existing options for ethanol production could help in meeting the requirements for volumes of renewable, advanced and cellulosic bioethanol production in the US required by the EPA’s Renewable Fuel Standard program. PMID:24088388

Trace Contaminant Control: An In-Depth Study of a Silica-Titania Composite for Photocatalytic Remediation of Closed-Environment Habitat Air

NASA Technical Reports Server (NTRS)

Coutts, Janelle L.

2013-01-01

This collection of studies focuses on a PCO system for the oxidation of a model compound, ethanol, using an adsorption-enhanced silica-TiO2 composite (STC) as the photocatalyst; studies are aimed at addressing the optimization of various parameters including light source, humidity, temperature, and possible poisoning events for use as part of a system for gaseous trace-contaminant control system in closed-environment habitats. The first goal focused on distinguishing the effect of photon flux (i.e., photons per unit time reaching a surface) from that of photon energy (i.e., wavelength) of a photon source on the PCO of ethanol. Experiments were conducted in a bench-scale annular reactor packed with STC pellets and irradiated with either a UV-A fluorescent black light blue lamp O max=365 nm) at its maximum light intensity or a UV-C germicidal lamp O. max=254 nm) at three levels of light intensity. The STC-catalyzed oxidation of ethanol was found to follow zero-order kinetics with respect to CO2 production, regardless of the photon source. Increased photon flux led to increased EtOH removal, mineralization, and oxidation rate accompanied by lower intermediate concentration in the effluent. The oxidation rate was higher in the reactor irradiated by UV-C than by UV-A (38.4 vs. 31.9 nM s-1 ) at the same photon flux, with similar trends for mineralization (53.9 vs. 43.4%) and reaction quantum efficiency (i.e., photonic efficiency, 63.3 vs. 50.1 nmol C02 mol photons-1 ). UV-C irradiation also led to decreased intermediate concentration in the effluent compared to UV -A irradiation. These results demonstrated that STC-catalyzed oxidation is enhanced by both increased photon flux and photon energy. The effect of temperature and relative humidity on the STC-catalyzed degradation of ethanol was also determined using the UV-A light source at its maximum intensity.

Improved growth and ethanol fermentation of Saccharomyces cerevisiae in the presence of acetic acid by overexpression of SET5 and PPR1.

PubMed

Zhang, Ming-Ming; Zhao, Xin-Qing; Cheng, Cheng; Bai, Feng-Wu

2015-12-01

To better understand the contribution of zinc-finger proteins to environmental stress tolerance, particularly inhibition from acetic acid, which is a potent inhibitor for cellulosic ethanol production by microbial fermentations, SET5 and PPR1 were overexpressed in Saccharomyces cerevisiae BY4741. With 5 g/L acetic acid addition, engineered strains BY4741/SET5 and BY4741/PPR1 showed improved growth and enhanced ethanol fermentation performance compared to that with the control strain. Similar results were also observed in ethanol production using corn stover hydrolysate. Further studies indicated that SET5 and PPR1 overexpression in S. cerevisiae significantly improved activities of antioxidant enzymes and ATP generation in the presence of acetic acid, and consequently decreased intracellular accumulation of reactive oxygen species (50.9 and 45.7%, respectively). These results revealed the novel functions of SET5 and PPR1 for the improvement of yeast acetic acid tolerance, and also implicated the involvement of these proteins in oxidative stress defense and energy metabolism in S. cerevisiae. This work also demonstrated that overexpression of SET5 and PPR1 would be a feasible strategy to increase cellulosic ethanol production efficiency. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Production of dimethylfuran for liquid fuels from biomass-derived carbohydrates.

PubMed

Román-Leshkov, Yuriy; Barrett, Christopher J; Liu, Zhen Y; Dumesic, James A

2007-06-21

Diminishing fossil fuel reserves and growing concerns about global warming indicate that sustainable sources of energy are needed in the near future. For fuels to be useful in the transportation sector, they must have specific physical properties that allow for efficient distribution, storage and combustion; these properties are currently fulfilled by non-renewable petroleum-derived liquid fuels. Ethanol, the only renewable liquid fuel currently produced in large quantities, suffers from several limitations, including low energy density, high volatility, and contamination by the absorption of water from the atmosphere. Here we present a catalytic strategy for the production of 2,5-dimethylfuran from fructose (a carbohydrate obtained directly from biomass or by the isomerization of glucose) for use as a liquid transportation fuel. Compared to ethanol, 2,5-dimethylfuran has a higher energy density (by 40 per cent), a higher boiling point (by 20 K), and is not soluble in water. This catalytic strategy creates a route for transforming abundant renewable biomass resources into a liquid fuel suitable for the transportation sector, and may diminish our reliance on petroleum.

77 FR 43591 - Tri-State Financial Co., LLC, (d/b/a North Country Ethanol), Red River Energy, LLC; Notice of Filing

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-25

... Financial Co., LLC, (d/b/a North Country Ethanol), Red River Energy, LLC; Notice of Filing Take notice that on July 10, 2012, Tri-State Financial Co., LLC, d/ b/a North Country Ethanol (Tri-State), and Red... the Tri- State's ethanol facility near Rosholt, in Roberts County, South Dakota (the Delivery Line...

Comparative life cycle assessment of lignocellulosic ethanol production: biochemical versus thermochemical conversion.

PubMed

Mu, Dongyan; Seager, Thomas; Rao, P Suresh; Zhao, Fu

2010-10-01

Lignocellulosic biomass can be converted into ethanol through either biochemical or thermochemical conversion processes. Biochemical conversion involves hydrolysis and fermentation while thermochemical conversion involves gasification and catalytic synthesis. Even though these routes produce comparable amounts of ethanol and have similar energy efficiency at the plant level, little is known about their relative environmental performance from a life cycle perspective. Especially, the indirect impacts, i.e. emissions and resource consumption associated with the production of various process inputs, are largely neglected in previous studies. This article compiles material and energy flow data from process simulation models to develop life cycle inventory and compares the fossil fuel consumption, greenhouse gas emissions, and water consumption of both biomass-to-ethanol production processes. The results are presented in terms of contributions from feedstock, direct, indirect, and co-product credits for four representative biomass feedstocks i.e., wood chips, corn stover, waste paper, and wheat straw. To explore the potentials of the two conversion pathways, different technological scenarios are modeled, including current, 2012 and 2020 technology targets, as well as different production/co-production configurations. The modeling results suggest that biochemical conversion has slightly better performance on greenhouse gas emission and fossil fuel consumption, but that thermochemical conversion has significantly less direct, indirect, and life cycle water consumption. Also, if the thermochemical plant operates as a biorefinery with mixed alcohol co-products separated for chemicals, it has the potential to achieve better performance than biochemical pathway across all environmental impact categories considered due to higher co-product credits associated with chemicals being displaced. The results from this work serve as a starting point for developing full life cycle assessment model that facilitates effective decision-making regarding lignocellulosic ethanol production.

Comparative Life Cycle Assessment of Lignocellulosic Ethanol Production: Biochemical Versus Thermochemical Conversion

NASA Astrophysics Data System (ADS)

Mu, Dongyan; Seager, Thomas; Rao, P. Suresh; Zhao, Fu

2010-10-01

Lignocellulosic biomass can be converted into ethanol through either biochemical or thermochemical conversion processes. Biochemical conversion involves hydrolysis and fermentation while thermochemical conversion involves gasification and catalytic synthesis. Even though these routes produce comparable amounts of ethanol and have similar energy efficiency at the plant level, little is known about their relative environmental performance from a life cycle perspective. Especially, the indirect impacts, i.e. emissions and resource consumption associated with the production of various process inputs, are largely neglected in previous studies. This article compiles material and energy flow data from process simulation models to develop life cycle inventory and compares the fossil fuel consumption, greenhouse gas emissions, and water consumption of both biomass-to-ethanol production processes. The results are presented in terms of contributions from feedstock, direct, indirect, and co-product credits for four representative biomass feedstocks i.e., wood chips, corn stover, waste paper, and wheat straw. To explore the potentials of the two conversion pathways, different technological scenarios are modeled, including current, 2012 and 2020 technology targets, as well as different production/co-production configurations. The modeling results suggest that biochemical conversion has slightly better performance on greenhouse gas emission and fossil fuel consumption, but that thermochemical conversion has significantly less direct, indirect, and life cycle water consumption. Also, if the thermochemical plant operates as a biorefinery with mixed alcohol co-products separated for chemicals, it has the potential to achieve better performance than biochemical pathway across all environmental impact categories considered due to higher co-product credits associated with chemicals being displaced. The results from this work serve as a starting point for developing full life cycle assessment model that facilitates effective decision-making regarding lignocellulosic ethanol production.

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

Ethanol production in small- to medium-size facilities

NASA Astrophysics Data System (ADS)

Hiler, E. A.; Coble, C. G.; Oneal, H. P.; Sweeten, J. M.; Reidenbach, V. G.; Schelling, G. T.; Lawhon, J. T.; Kay, R. D.; Lepori, W. A.; Aldred, W. H.

1982-04-01

In early 1980 system design criteria were developed for a small-scale ethanol production plant. The plant was eventually installed on November 1, 1980. It has a production capacity of 30 liters per hour; this can be increased easily (if desired) to 60 liters per hour with additional fermentation tanks. Sixty-six test runs were conducted to date in the alcohol production facility. Feedstocks evaluated in these tests include: corn (28 runs); grain sorghum (33 runs); grain sorghum grits (1 run); half corn/half sorghum (1 run); and sugarcane juice (3 runs). In addition, a small bench-scale fermentation and distillation system was used to evaluate sugarcane and sweet sorghum feedstocks prior to their evaluation in the larger unit. In each of these tests, evaluation of the following items was conducted: preprocessing requirements; operational problems; conversion efficiency (for example, liters of alcohol produced per kilogram of feedstock); energy balance and efficiency; nutritional recovery from stillage; solids separation by screw press; chemical characterization of stillage including liquid and solids fractions; wastewater requirements; and air pollution potential.

Methodology for the optimal design of an integrated first and second generation ethanol production plant combined with power cogeneration.

PubMed

Bechara, Rami; Gomez, Adrien; Saint-Antonin, Valérie; Schweitzer, Jean-Marc; Maréchal, François

2016-08-01

The application of methodologies for the optimal design of integrated processes has seen increased interest in literature. This article builds on previous works and applies a systematic methodology to an integrated first and second generation ethanol production plant with power cogeneration. The methodology breaks into process simulation, heat integration, thermo-economic evaluation, exergy efficiency vs. capital costs, multi-variable, evolutionary optimization, and process selection via profitability maximization. Optimization generated Pareto solutions with exergy efficiency ranging between 39.2% and 44.4% and capital costs from 210M$ to 390M$. The Net Present Value was positive for only two scenarios and for low efficiency, low hydrolysis points. The minimum cellulosic ethanol selling price was sought to obtain a maximum NPV of zero for high efficiency, high hydrolysis alternatives. The obtained optimal configuration presented maximum exergy efficiency, hydrolyzed bagasse fraction, capital costs and ethanol production rate, and minimum cooling water consumption and power production rate. Copyright © 2016 Elsevier Ltd. All rights reserved.

Machine learning of accurate energy-conserving molecular force fields.

PubMed

Chmiela, Stefan; Tkatchenko, Alexandre; Sauceda, Huziel E; Poltavsky, Igor; Schütt, Kristof T; Müller, Klaus-Robert

2017-05-01

Using conservation of energy-a fundamental property of closed classical and quantum mechanical systems-we develop an efficient gradient-domain machine learning (GDML) approach to construct accurate molecular force fields using a restricted number of samples from ab initio molecular dynamics (AIMD) trajectories. The GDML implementation is able to reproduce global potential energy surfaces of intermediate-sized molecules with an accuracy of 0.3 kcal mol -1 for energies and 1 kcal mol -1 Å̊ -1 for atomic forces using only 1000 conformational geometries for training. We demonstrate this accuracy for AIMD trajectories of molecules, including benzene, toluene, naphthalene, ethanol, uracil, and aspirin. The challenge of constructing conservative force fields is accomplished in our work by learning in a Hilbert space of vector-valued functions that obey the law of energy conservation. The GDML approach enables quantitative molecular dynamics simulations for molecules at a fraction of cost of explicit AIMD calculations, thereby allowing the construction of efficient force fields with the accuracy and transferability of high-level ab initio methods.

Impacts of kafirin allelic diversity, starch content, and protein digestibility on ethanol conversion efficiency in grain sorghum

USDA-ARS?s Scientific Manuscript database

Seed protein and starch composition determines the efficiency of ethanol conversion in the production of grain-based biofuels. Sorghum, highly water- and nutrient-efficient, has the potential to replace fuel crops with greater irrigation and fertiliser requirements, such as maize. However, sorghum g...

Bioethanol production from fermentable sugar juice.

PubMed

Zabed, Hossain; Faruq, Golam; Sahu, Jaya Narayan; Azirun, Mohd Sofian; Hashim, Rosli; Boyce, Amru Nasrulhaq

2014-01-01

Bioethanol production from renewable sources to be used in transportation is now an increasing demand worldwide due to continuous depletion of fossil fuels, economic and political crises, and growing concern on environmental safety. Mainly, three types of raw materials, that is, sugar juice, starchy crops, and lignocellulosic materials, are being used for this purpose. This paper will investigate ethanol production from free sugar containing juices obtained from some energy crops such as sugarcane, sugar beet, and sweet sorghum that are the most attractive choice because of their cost-effectiveness and feasibility to use. Three types of fermentation process (batch, fed-batch, and continuous) are employed in ethanol production from these sugar juices. The most common microorganism used in fermentation from its history is the yeast, especially, Saccharomyces cerevisiae, though the bacterial species Zymomonas mobilis is also potentially used nowadays for this purpose. A number of factors related to the fermentation greatly influences the process and their optimization is the key point for efficient ethanol production from these feedstocks.

Bioethanol Production from Fermentable Sugar Juice

PubMed Central

Zabed, Hossain; Faruq, Golam; Sahu, Jaya Narayan; Azirun, Mohd Sofian; Hashim, Rosli; Nasrulhaq Boyce, Amru

2014-01-01

Bioethanol production from renewable sources to be used in transportation is now an increasing demand worldwide due to continuous depletion of fossil fuels, economic and political crises, and growing concern on environmental safety. Mainly, three types of raw materials, that is, sugar juice, starchy crops, and lignocellulosic materials, are being used for this purpose. This paper will investigate ethanol production from free sugar containing juices obtained from some energy crops such as sugarcane, sugar beet, and sweet sorghum that are the most attractive choice because of their cost-effectiveness and feasibility to use. Three types of fermentation process (batch, fed-batch, and continuous) are employed in ethanol production from these sugar juices. The most common microorganism used in fermentation from its history is the yeast, especially, Saccharomyces cerevisiae, though the bacterial species Zymomonas mobilis is also potentially used nowadays for this purpose. A number of factors related to the fermentation greatly influences the process and their optimization is the key point for efficient ethanol production from these feedstocks. PMID:24715820

A metal-free electrocatalyst for carbon dioxide reduction to multi-carbon hydrocarbons and oxygenates

NASA Astrophysics Data System (ADS)

Wu, Jingjie; Ma, Sichao; Sun, Jing; Gold, Jake I.; Tiwary, Chandrasekhar; Kim, Byoungsu; Zhu, Lingyang; Chopra, Nitin; Odeh, Ihab N.; Vajtai, Robert; Yu, Aaron Z.; Luo, Raymond; Lou, Jun; Ding, Guqiao; Kenis, Paul J. A.; Ajayan, Pulickel M.

2016-12-01

Electroreduction of carbon dioxide into higher-energy liquid fuels and chemicals is a promising but challenging renewable energy conversion technology. Among the electrocatalysts screened so far for carbon dioxide reduction, which includes metals, alloys, organometallics, layered materials and carbon nanostructures, only copper exhibits selectivity towards formation of hydrocarbons and multi-carbon oxygenates at fairly high efficiencies, whereas most others favour production of carbon monoxide or formate. Here we report that nanometre-size N-doped graphene quantum dots (NGQDs) catalyse the electrochemical reduction of carbon dioxide into multi-carbon hydrocarbons and oxygenates at high Faradaic efficiencies, high current densities and low overpotentials. The NGQDs show a high total Faradaic efficiency of carbon dioxide reduction of up to 90%, with selectivity for ethylene and ethanol conversions reaching 45%. The C2 and C3 product distribution and production rate for NGQD-catalysed carbon dioxide reduction is comparable to those obtained with copper nanoparticle-based electrocatalysts.

Renewable energy production by photoelectrochemical oxidation of organic wastes using WO3 photoanodes.

PubMed

Raptis, Dimitrios; Dracopoulos, Vassilios; Lianos, Panagiotis

2017-07-05

The present work has studied renewable hydrogen production by photoelectrocatalytic degradation of model organic substances representing biomass derived organic wastes. Its purpose was to show that renewable energy can be produced by consuming wastes. The study has been carried out by employing nanoparticulate WO 3 photoanodes in the presence of ethanol, glycerol or sorbitol, i.e. three substances which are among typical biomass products. In these substances, the molecular weight and the number of hydroxyl groups increases from ethanol to sorbitol. The photocurrent produced by the cell was the highest in the presence of ethanol, smaller in the case of glycerol and further decreased in the presence of sorbitol. The photocurrent was roughly the double of that produced in the absence of an organic additive thus demonstrating current doubling phenomena. Hydrogen was produced only under illumination and was monitored at two forward bias, 0.8 and 1.6V vs Ag/AgCl. Hydrogen production rates followed the same order as the photocurrent thus indicating that hydrogen production by reduction of protons mainly depends on the current flowing through the external circuit connecting photoanode with cathode. The maximum solar-to-hydrogen efficiency reached by the present system was 2.35%. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of various light curing methods on the leachability of uncured substances and hardness of a composite resin.

PubMed

Moon, H-J; Lee, Y-K; Lim, B-S; Kim, C-W

2004-03-01

The purpose of this study was to evaluate the effect of the various light curing units (plasma arc, halogen and light-emitting diodes) and irradiation methods (one-step, two-step and pulse) using different light energy densities on the leachability of unreacted monomers (Bis-GMA and UDMA) and the surface hardness of a composite resin (Z250, 3M). Leachability of the specimens immersed for 7 days in ethanol was analysed by HPLC. Vicker's hardness number (VHN) was measured immediately after curing (IC) and after immersion in ethanol for 7 days. Various irradiation methods with three curing units resulted in differences in the amount of leached monomers and VHN of IC when light energy density was lower than 17.0 J cm(-2) (P = 0.05). However, regardless of curing units and irradiation methods, these results were not different when the time or light energy density increased. When similar light energy density was irradiated (15.6-17.7 J cm(-2)), the efficiency of irradiation methods was different by the following order: one-step > or = two-step > pulse. These results suggest that the amount of leached monomers and VHN were influenced by forming polymer structure in activation and initiation stages of polymerization process with different light source energies and curing times.

A possible role of a cerebral energy gene in alcoholism.

PubMed

Ribeiro, A F; Correia, D; Boerngen-Lacerda, R; Brunialti-Godard, A L

2012-02-17

We examined a possible relationship between genes responsible for energy metabolism of the brain and addictive behavior in an animal model. We used non-inbred, Swiss mice exposed to a three-bottle free-choice model [water, 5% (v/v) ethanol, and 10% (v/v) ethanol] over a 16-week period, consisting of four phases: acquisition, withdrawal, reexposure, and quinine-adulteration. The mice were then behaviorally classified into three groups: loss-of-control-drinker (preference for ethanol and high levels of consumption during all phases, N = 6), heavy-drinker (preference for ethanol and high levels of consumption during acquisition and reduction during quinine-adulteration, N = 7), and light-drinker (preference for water during all phases, N = 10). Another group only received tap water (ethanol-naive control mice, N = 9). Further analysis using quantitative real-time PCR showed that in mice behaviorally classified as loss-of-control-drinkers, there was a significant inverse correlation between transcript levels of the Hadh gene and those of other energy metabolism genes in the nucleus of the amygdala, suggesting that this pathway may contribute to ethanol consumption in these mice. We conclude that cerebral energy metabolism is involved with ethanol addiction, meriting further study.

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.

Production of gluten and germ by ethanol fermentation of raw corn

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

Not Available

1987-01-01

The Illinois ethanol fuel industry has grown to be an important part of our state's economy over the past 10 years. It provides an additional market for Illinois' abundant corn production, provides many industrial jobs, and substitutes a home-grown renewable energy resource for imported oil. More than 30 percent of all gasoline sold in Illinois contains 10 percent ethanol. The economics of producing ethanol from corn is strongly affected by the byproduct value and by the energy required in the production process. This document reports on efforts to research a new microbial process that would improve the ethanol fermentation processmore » in both these areas. The new process allows direct fermentation of corn starch to ethanol without the usual requirement of cooking the corn. This reduces the amount of energy needed for production and recovers the protein-containing gluten and oil-containing germ with all of the original food value intact.« less

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.

Comparative behaviour of yeast strains for ethanolic fermentation of culled apple juice.

PubMed

Modi, D R; Garg, S K; Johri, B N

1998-07-01

The culled apple juice contained (% w/v): nitrogen, 0.036; total sugars, 11.6 and was of pH 3.9. Saccharomyces cerevisiae NCIM 3284, Pichia kluyeri and Candida krusei produced more ethanol from culled apple juice at its optimum initial pH 4.5, whereas S. cerevisiae NCIM 3316 did so at pH 5.0. An increase in sugar concentration of apple juice from natural 11.6% to 20% exhibited enhanced ethanol production and improved fermentation efficiency of both the S. cerevisiae strains, whereas P. kluyveri and C. krusei produced high ethanol at 11.6% and 16.0% sugar levels, respectively. Urea was stimulatory for ethanol production as well as fermentation efficiency of the yeast strains under study.

Performance testing of Zymomonas mobilis metabolically engineered for cofermentation of glucose, xylose, and arabinose.

PubMed

Lawford, Hugh G; Rousseau, Joyce D

2002-01-01

IOGEN Corporation of Ottawa, Canada, has recently built a 40t/d biomass-to-ethanol demonstration plant adjacent to its enzyme production facility. It has partnered with the University of Toronto to test the C6/C5 cofermenta-tion performance characteristics of the National Renewable Energy Labora-tory's metabolically engineered Zymomonas mobilis using various biomass hydrolysates. IOGEN's feedstocks are primarily agricultural wastes such as corn stover and wheat straw. Integrated recombinant Z. mobilis strain AX101 grows on D-xylose and/or L-arabinose as the sole carbon/energy sources and ferments these pentose sugars to ethanol in high yield. Strain AX101 lacks the tetracycline resistance gene that was a common feature of other recombinant Zm constructs. Genomic integration provides reliable cofermentation performance in the absence of antibiotics, another characteristic making strain AX101 attractive for industrial cellulosic ethanol production. In this work, IOGEN's biomass hydrolysate was simulated by a pure sugar medium containing 6% (w/v) glucose, 3% xylose, and 0.35% arabinose. At a level of 3 g/L (dry solids), corn steep liquor with inorganic nitrogen (0.8 g/L of ammonium chloride or 1.2 g/L of diammonium phosphate) was a cost-effective nutritional supplement. In the absence of acetic acid, the maximum volumetric ethanol productivity of a continuous fermentation at pH 5.0 was 3.54 g/L x h. During prolonged continuous fermentation, the efficiency of sugar-to-ethanol conversion (based on total sugar load) was maintained at >85%. At a level of 0.25% (w/v) acetic acid, the productivity decreased to 1.17 g/L x h at pH 5.5. Unlike integrated, xylose-utilizing rec Zm strain C25, strain AX101 produces less lactic acid as byproduct, owing to the fact that the Escherichia coli arabinose genes are inserted into a region of the host chromosome tentatively assigned to the gene for D-lactic acid dehydrogenase. In pH-controlled batch fermentations with sugar mixtures, the order of sugar exhaustion from the medium was glucose followed by xylose and arabinose. Both the total sugar load and the sugar ratio were shown to be important determinants for efficient cofermentation. Ethanol at a level of 3% (w/v) was implicated as both inhibitory to pentose fermentation and as a potentiator of acetic acid inhibition of pentose fermentation at pH 5.5. The effect of ethanol may have been underestimated in other assessments of acetic acid sensitivity. This work underscores the importance of employing similar assay conditions in making comparative assessments of biocatalyst fermentation performance.

Treatment of high ethanol concentration wastewater by biological sand filters: enhanced COD removal and bacterial community dynamics.

PubMed

Rodriguez-Caballero, A; Ramond, J-B; Welz, P J; Cowan, D A; Odlare, M; Burton, S G

2012-10-30

Winery wastewater is characterized by its high chemical oxygen demand (COD), seasonal occurrence and variable composition, including periodic high ethanol concentrations. In addition, winery wastewater may contain insufficient inorganic nutrients for optimal biodegradation of organic constituents. Two pilot-scale biological sand filters (BSFs) were used to treat artificial wastewater: the first was amended with ethanol and the second with ethanol, inorganic nitrogen (N) and phosphorus (P). A number of biochemical parameters involved in the removal of pollutants through BSF systems were monitored, including effluent chemistry and bacterial community structures. The nutrient supplemented BSF showed efficient COD, N and P removal. Comparison of the COD removal efficiencies of the two BSFs showed that N and P addition enhanced COD removal efficiency by up to 16%. Molecular fingerprinting of BSF sediment samples using denaturing gradient gel electrophoresis (DGGE) showed that amendment with high concentrations of ethanol destabilized the microbial community structure, but that nutrient supplementation countered this effect. Copyright © 2012 Elsevier Ltd. All rights reserved.

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.

Conformational Changes of the Alanine Dipeptide in Water-Ethanol Binary Mixtures.

PubMed

Almeida, Glauco G; Cordeiro, João M M; Martín, M Elena; Aguilar, Manuel A

2016-04-12

Experimental work developed in the last years has evidenced the capacity of alcohols and polyalcohols to modify the energy landscape of peptides and proteins. However, the mechanism underlying this effect is not clear. Taking as a model system the alanine dipeptide (AD) we perform a QM/MM study in water, ethanol, and a 40-60% in volume water-ethanol mixture. The AD molecule was described at the MP2/aug-cc-pVDZ level. In polar solution, only αR and PPII conformers contribute in an appreciable way to the conformational equilibrium. The final in solution αR-PPII free energy difference is determined from the interplay between the internal energy of the dipeptide and the solute-solvent interaction free energy. Internal energy favors the formation of PPII, whereas, on the contrary, solute-solvent interaction is favorable to αR, so any factor that decreases the solute-solvent interaction free energy will increase the PPII population. The addition of ethanol increases the stability of the PPII conformer. Our results point to the presence of preferential solvation in this system, the composition of the first solvation shell in the binary mixture being dominated by water molecules. Remarkably, this fact does not affect the differential conformational stability that is controlled by long-range interactions. From the analysis of solvent density maps it is concluded that, in the water-ethanol mixture, ethanol molecules are more likely found around the alanine side chain and the carbonyl group, but while in PPII ethanol molecules interact mainly with the carbonyl group of the N-terminal end, in C5 the interaction is with the carbonyl group of the C-terminal end. In αR, ethanol interacts with both carbonyl groups.

Speeding up the self-assembly of a DNA nanodevice using a variety of polar solvents

NASA Astrophysics Data System (ADS)

Kang, Di; Duan, Ruixue; Tan, Yerpeng; Hong, Fan; Wang, Boya; Chen, Zhifei; Xu, Shaofang; Lou, Xiaoding; Wei, Wei; Yurke, Bernard; Xia, Fan

2014-11-01

The specific recognition and programmable assembly properties make DNA a potential material for nanodevices. However, the more intelligent the nanodevice is, the more complicated the structure of the nanodevice is, which limits the speed of DNA assembly. Herein, to address this problem, we investigate the performance of DNA Strand Displacement Reaction (DSDR) in a mixture of polar organic solvents and aqueous buffer and demonstrate that the organic polar solvent can speed up DNA self-assembly efficiently. Taking DSDR in 20% ethanol as an example, first we have demonstrated that the DSDR is highly accelerated in the beginning of the reaction and it can complete 60% of replacement reactions (160% enhancement compared with aqueous buffer) in the first 300 seconds. Secondly, we calculated that the ΔΔG of the DSDR in 20% ethanol (-18.2 kcal mol-1) is lower than that in pure aqueous buffer (-32.6 kcal mol-1), while the activation energy is lowered by introducing ethanol. Finally, we proved that the DSDR on the electrode surface can also be accelerated using this simple strategy. More importantly, to test the efficacy of this approach in nanodevices with a complicated and slow DNA self-assembly process, we apply this strategy in the hybridization chain reaction (HCR) and prove the acceleration is fairly obvious in 20% ethanol, which demonstrates the feasibility of the proposed strategy in DNA nanotechnology and DNA-based biosensors.The specific recognition and programmable assembly properties make DNA a potential material for nanodevices. However, the more intelligent the nanodevice is, the more complicated the structure of the nanodevice is, which limits the speed of DNA assembly. Herein, to address this problem, we investigate the performance of DNA Strand Displacement Reaction (DSDR) in a mixture of polar organic solvents and aqueous buffer and demonstrate that the organic polar solvent can speed up DNA self-assembly efficiently. Taking DSDR in 20% ethanol as an example, first we have demonstrated that the DSDR is highly accelerated in the beginning of the reaction and it can complete 60% of replacement reactions (160% enhancement compared with aqueous buffer) in the first 300 seconds. Secondly, we calculated that the ΔΔG of the DSDR in 20% ethanol (-18.2 kcal mol-1) is lower than that in pure aqueous buffer (-32.6 kcal mol-1), while the activation energy is lowered by introducing ethanol. Finally, we proved that the DSDR on the electrode surface can also be accelerated using this simple strategy. More importantly, to test the efficacy of this approach in nanodevices with a complicated and slow DNA self-assembly process, we apply this strategy in the hybridization chain reaction (HCR) and prove the acceleration is fairly obvious in 20% ethanol, which demonstrates the feasibility of the proposed strategy in DNA nanotechnology and DNA-based biosensors. Electronic supplementary information (ESI) available: Experimental procedures and analytical data are provided. See DOI: 10.1039/c4nr02257b

Achieving Energy Security in the Caribbean Basin

DTIC Science & Technology

2009-04-01

however. Jamaica Broilers Ethanol, a subsidiary of the private company Jamaica Broilers Group, is spending an additional $15 million to expand its...limited basis. Jamaica Broilers , for example, produces 5MW of energy, but it is investing approximately $5 million to generate an additional 10MW of...Minister Upbeat about Jamaica’s Ethanol Prospects," 16 Dec 08 50 The BioEnergySite News Desk, "Jamaica Broilers Ethanol to Double Capacity," Feb 09

Ethanol production by fermentation using immobilized cells of Saccharomyces cerevisiae in cashew apple bagasse.

PubMed

Pacheco, Alexandre Monteiro; Gondim, Diego Romão; Gonçalves, Luciana Rocha Barros

2010-05-01

In this work, cashew apple bagasse (CAB) was used for Saccharomyces cerevisiae immobilization. The support was prepared through a treatment with a solution of 3% HCl, and delignification with 2% NaOH was also conducted. Optical micrographs showed that high populations of yeast cells adhered to pre-treated CAB surface. Ten consecutive fermentations of cashew apple juice for ethanol production were carried out using immobilized yeasts. High ethanol productivity was observed from the third fermentation assay until the tenth fermentation. Ethanol concentrations (about 19.82-37.83 g L(-1) in average value) and ethanol productivities (about 3.30-6.31 g L(-1) h(-1)) were high and stable, and residual sugar concentrations were low in almost all fermentations (around 3.00 g L(-1)) with conversions ranging from 44.80% to 96.50%, showing efficiency (85.30-98.52%) and operational stability of the biocatalyst for ethanol fermentation. Results showed that cashew apple bagasse is an efficient support for cell immobilization aiming at ethanol production.

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.

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.

Ultrafast synthesis of flower-like ordered Pd3Pb nanocrystals with superior electrocatalytic activities towards oxidation of formic acid and ethanol

NASA Astrophysics Data System (ADS)

Jana, Rajkumar; Subbarao, Udumula; Peter, Sebastian C.

2016-01-01

Ordered intermetallic nanocrystals with high surface area are highly promising as efficient catalysts for fuel cell applications because of their unique electrocatalytic properties. The present work discusses about the controlled synthesis of ordered intermetallic Pd3Pb nanocrystals in different morphologies at relatively low temperature for the first time by polyol and hydrothermal methods both in presence and absence of surfactant. Here for the first time we report surfactant free synthesis of ordered flower-like intermetallic Pd3Pb nanocrystals in 10 s. The structural characteristics of the nanocrystals are confirmed by powder X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy. The as synthesized ordered Pd3Pb nanocrystals exhibit far superior electrocatalytic activity and durability towards formic acid and ethanol oxidation over commercially available Pd black (Pd/C). The morphological variation of nanocrystals plays a crucial role in the electrocatalytic oxidation of formic acid and ethanol. Among the catalysts, the flower-like Pd3Pb shows enhanced activity and stability in electrocatalytic formic acid and ethanol oxidation. The current density and mass activity of flower-like Pd3Pb catalyst are higher by 2.5 and 2.4 times than that of Pd/C for the formic acid oxidation and 1.5 times each for ethanol oxidation.

Suppressing the Coffee-Ring Effect in Semitransparent MnO2 Film for a High-Performance Solar-Powered Energy Storage Window.

PubMed

Jin, Huanyu; Qian, Jiasheng; Zhou, Limin; Yuan, Jikang; Huang, Haitao; Wang, Yu; Tang, Wing Man; Chan, Helen Lai Wa

2016-04-13

We introduce a simple and effective method to deposit a highly uniform and semitransparent MnO2 film without coffee-ring effect (CRE) by adding ethanol into MnO2 ink for transparent capacitive energy storage devices. By carefully controlling the amount of ethanol added in the MnO2 droplet, we could significantly reduce the CRE and thus improve the film uniformity. The electrochemical properties of supercapacitor (SC) devices using semitransparent MnO2 film electrodes with or without CRE were measured and compared. The SC device without CRE shows a superior capacitance, high rate capability, and lower contact resistance. The CRE-free device could achieve a considerable volumetric capacitance of 112.2 F cm(-3), resulting in a high volumetric energy density and power density of 10 mWh cm(-3) and 8.6 W cm(-3), respectively. For practical consideration, both flexible SC and large-area rigid SC devices were fabricated to demonstrate their potential for flexible transparent electronic application and capacitive energy-storage window application. Moreover, a solar-powered energy storage window which consists of a commercial solar cell and our studied semitransparent MnO2-film-based SCs was assembled. These SCs could be charged by the solar cell and light up a light emitting diode (LED), demonstrating their potential for self-powered systems and energy-efficient buildings.

Machine learning of accurate energy-conserving molecular force fields

PubMed Central

Chmiela, Stefan; Tkatchenko, Alexandre; Sauceda, Huziel E.; Poltavsky, Igor; Schütt, Kristof T.; Müller, Klaus-Robert

2017-01-01

Using conservation of energy—a fundamental property of closed classical and quantum mechanical systems—we develop an efficient gradient-domain machine learning (GDML) approach to construct accurate molecular force fields using a restricted number of samples from ab initio molecular dynamics (AIMD) trajectories. The GDML implementation is able to reproduce global potential energy surfaces of intermediate-sized molecules with an accuracy of 0.3 kcal mol−1 for energies and 1 kcal mol−1 Å̊−1 for atomic forces using only 1000 conformational geometries for training. We demonstrate this accuracy for AIMD trajectories of molecules, including benzene, toluene, naphthalene, ethanol, uracil, and aspirin. The challenge of constructing conservative force fields is accomplished in our work by learning in a Hilbert space of vector-valued functions that obey the law of energy conservation. The GDML approach enables quantitative molecular dynamics simulations for molecules at a fraction of cost of explicit AIMD calculations, thereby allowing the construction of efficient force fields with the accuracy and transferability of high-level ab initio methods. PMID:28508076

Development of a performance-based industrial energy efficiency indicator for corn refining plants.

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

Boyd, G. A.; Decision and Information Sciences; USEPA

2006-07-31

Organizations that implement strategic energy management programs have the potential to achieve sustained energy savings if the programs are carried out properly. A key opportunity for achieving energy savings that plant managers can take is to determine an appropriate level of energy performance by comparing their plant's performance with that of similar plants in the same industry. Manufacturing facilities can set energy efficiency targets by using performance-based indicators. The U.S. Environmental Protection Agency (EPA), through its ENERGY STAR{reg_sign} program, has been developing plant energy performance indicators (EPIs) to encourage a variety of U.S. industries to use energy more efficiently. Thismore » report describes work with the corn refining industry to provide a plant-level indicator of energy efficiency for facilities that produce a variety of products--including corn starch, corn oil, animal feed, corn sweeteners, and ethanol--for the paper, food, beverage, and other industries in the United States. Consideration is given to the role that performance-based indicators play in motivating change; the steps needed to develop indicators, including interacting with an industry to secure adequate data for an indicator; and the actual application and use of an indicator when complete. How indicators are employed in the EPA's efforts to encourage industries to voluntarily improve their use of energy is discussed as well. The report describes the data and statistical methods used to construct the EPI for corn refining plants. Individual equations are presented, as are the instructions for using them in an associated Excel spreadsheet.« less

Biodetoxification of toxins generated from lignocellulose pretreatment using a newly isolated fungus, Amorphotheca resinae ZN1, and the consequent ethanol fermentation.

PubMed

Zhang, Jian; Zhu, Zhinan; Wang, Xiaofeng; Wang, Nan; Wang, Wei; Bao, Jie

2010-11-22

Degradation of the toxic compounds generated in the harsh pretreatment of lignocellulose is an inevitable step in reducing the toxin level for conducting practical enzymatic hydrolysis and ethanol fermentation processes. Various detoxification methods have been tried and many negative outcomes were found using these methods, such as the massive freshwater usage and wastewater generation, loss of the fine lignocellulose particles and fermentative sugars and incomplete removal of inhibitors. An alternate method, biodetoxification, which degrades the toxins as part of their normal metabolism, was considered a promising option for the removal of toxins without causing the above problems. A kerosene fungus strain, Amorphotheca resinae ZN1, was isolated from the microbial community growing on the pretreated corn stover material. The degradation of the toxins as well as the lignocelluloses-derived sugars was characterized in different ways, and the results show that A. resinae ZN1 utilized each of these toxins and sugars as the sole carbon sources efficiently and grew quickly on the toxins. It was found that the solid-state culture of A. resinae ZN1 on various pretreated lignocellulose feedstocks such as corn stover, wheat straw, rice straw, cotton stalk and rape straw degraded all kinds of toxins quickly and efficiently. The consequent simultaneous saccharification and ethanol fermentation was performed at the 30% (wt/wt) solid loading of the detoxified lignocellulosic feedstocks without a sterilization step, and the ethanol titer in the fermentation broth reached above 40 g/L using food crop residues as feedstocks. The advantages of the present biodetoxification by A. resinae ZN1 over the known detoxification methods include zero energy input, zero wastewater generation, complete toxin degradation, processing on solid pretreated material, no need for sterilization and a wide lignocellulose feedstock spectrum. These advantages make it possible for industrial applications with fast and efficient biodetoxification to remove toxins generated during intensive lignocellulose pretreatment.

SIRT1 IS INVOLVED IN ENERGY METABOLISM: THE ROLE OF CHRONIC ETHANOL FEEDING AND RESVERATROL

PubMed Central

Oliva, Joan; French, Barbara A.; Li, Jun; Bardag-Gorce, Fawzia; Fu, Paul; French, Samuel W.

2010-01-01

Sirt1, a deacetylase involved in regulating energy metabolism in response to calorie restriction, is up regulated after chronic ethanol feeding using the intragastric feeding model of alcohol liver disease. PGC1α is also up regulated in response to ethanol. These changes are consistent with activation of the Sirt1/PGC1α pathway of metabolism and aging, involved in alcohol liver disease including steatosis, necrosis and fibrosis of the liver. To test this hypothesis, male rats fed ethanol intragastrically for 1 month were compared with rats fed ethanol plus resveratrol or naringin. Liver histology showed macrovesicular steatosis caused by ethanol and this change was unchanged by resveratrol or naringin treatment. Necrosis occurred with ethanol alone but was accentuated by resveratrol treatment, as was fibrosis. The expression of Sirt1 and PGC1α was increased by ethanol but not when naringin or resveratrol was fed with ethanol. Sirt3 was also up regulated by ethanol but not when resveratrol was fed with ethanol. These results support the concept that ethanol induces the Sirt1/PGC1α pathway of gene regulation and both naringin and resveratrol prevent the activation of this pathway by ethanol. However, resveratrol did not reduce the liver pathology caused by chronic ethanol feeding. PMID:18793633

Outlook for Biomass Ethanol Production and Demand

EIA Publications

2000-01-01

This paper presents a midterm forecast for biomass ethanol production under three different technology cases for the period 2000 to 2020, based on projections developed from the Energy Information Administration's National Energy Modeling System. An overview of cellulose conversion technology and various feedstock options and a brief history of ethanol usage in the United States are also presented.

Production of ethanol from a mixture of waste paper and kitchen waste via a process of successive liquefaction, presaccharification, and simultaneous saccharification and fermentation.

PubMed

Nishimura, Hiroto; Tan, Li; Kira, Noriko; Tomiyama, Shigeo; Yamada, Kazuo; Sun, Zhao-Yong; Tang, Yue-Qin; Morimura, Shigeru; Kida, Kenji

2017-09-01

Efficient ethanol production from waste paper requires the addition of expensive nutrients. To reduce the production cost of ethanol from waste paper, a study on how to produce ethanol efficiently by adding kitchen waste (potentially as a carbon source, nutrient source, and acidity regulator) to waste paper was performed and a process of successive liquefaction, presaccharification, and simultaneous saccharification and fermentation (L+PSSF) was developed. The individual saccharification performances of waste paper and kitchen waste were not influenced by their mixture. Liquefaction of kitchen waste at 90°C prior to presaccharification and simultaneous saccharification and fermentation (PSSF) was essential for efficient ethanol fermentation. Ethanol at concentrations of 46.6 or 43.6g/l was obtained at the laboratory scale after fermentation for 96h, even without pH adjustment and/or the addition of extra nutrients. Similarly, ethanol at a concentration of 45.5g/l was obtained at the pilot scale after fermentation for 48h. The ethanol concentration of L+PSSF of the mixture of waste paper and kitchen waste was comparable to that of PSSF of waste paper with added nutrients (yeast extract and peptone) and pH adjustment using H 2 SO 4 , indicating that kitchen waste is not only a carbon source but also an excellent nutrient source and acidity regulator for fermentation of the mixture of waste paper and kitchen waste. Copyright © 2017. Published by Elsevier Ltd.

Enhanced cellulosic ethanol production from mild-alkali pretreated rice straw in SSF using Clavispora NRRL Y-50464

USDA-ARS?s Scientific Manuscript database

This study reports the first lower-cost cellulosic ethanol production from mild alkali retreated rice straw using a native ß-glucosidase producing yeast strain, Clavispora NRRL Y-50464 by SSF. Ethanol production and efficiency of ethanol conversion from 10, 15, and 20% of solids loading of rice stra...

Ultrathin layered double hydroxide nanosheets with Ni(III) active species obtained by exfoliation for highly efficient ethanol electrooxidation.

PubMed

Xu, Liang; Wang, Zhe; Chen, Xu; Qu, Zongkai; Li, Feng; Yang, Wensheng

2018-01-10

The development of non-precious metal electrocatalysts for renewable energy conversion and storage is compelling but greatly challenging due to low activity of the existing catalysts. Herein, the ultrathin NiAl-layered double hydroxide nanosheets (NiAl-LDH-NSs) are prepared by simple liquid-exfoliation of bulk NiAl-LDHs and first used as ethanol electrooxidation catalysts. The ultrathin two-dimensional (2D) structure ensures that the LDH nanosheets expose a greater number of active sites. More importantly, much Ni(III) active species (NiOOH) in the ultrathin nanosheets are formed by the exfoliation process, which play an authentic catalytic role in the ethanol oxidation reaction (EOR). The presence of NiOOH remarkably improves the reactivity and electrical conductivity of LDH nanosheets. These synergistic effects lead to strikingly more than 30 times enhanced EOR activity of NiAl-LDH-NSs compared to bulk NiAl-LDHs. The obtained electrocatalytic activity is also much better than those of most Ni- and LDH-based EOR catalysts reported to date. In addition, the ultrathin NiAl-LDH-NS electrocatalyst also exhibits good long-term stability (maintain 81.8% of the original value after 10000 s). This study not only provides a highly competitive EOR catalyst, but also opens new avenues toward the design of highly efficient electrode materials that have various potential applications in supercapacitor, Ni-MH battery and other electrocatalytic systems.

Yeast metabolic engineering for hemicellulosic ethanol production

Treesearch

Jennifer Van Vleet; Thomas W. Jeffries

2009-01-01

Efficient fermentation of hemicellulosic sugars is critical for the bioconversion of lignocellulosics to ethanol. Efficient sugar uptake through the heterologous expression of yeast and fungal xylose/glucose transporters can improve fermentation if other metabolic steps are not rate limiting. Rectification of cofactor imbalances through heterologous expression of...

Capital requirements and fuel-cycle energy and emissions impacts of potential PNGV fuels.

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

Johnson, L.; Mintz, M.; Singh, M.

1999-03-11

Our study reveals that supplying gasoline-equivalent demand for the low-market-share scenario requires a capital investment of less thanmore » $$40 billion for all fuels except H{sub 2}, which will require a total cumulative investment of $$150 billion. By contrast, cumulative capital investments under the high-market-share scenario are $50 billion for LNG, $90 billion for ethanol, $100 billion for methanol, $160 billion for CNG and DME, and $560 billion for H{sub 2}. Although these substantial capital requirements are spread over many years, their magnitude could pose a challenge to the widespread introduction of 3X vehicles. Fossil fuel use by US light-duty vehicles declines significantly with introduction of 3X vehicles because of fuel-efficiency improvements for 3X vehicles and because of fuel substitution (which applies to the nonpetroleum-fueled alternatives). Petroleum use for light-duty vehicles in 2030 is reduced by as much as 45% relative to the reference scenario. GHG emissions follow a similar pattern. Total GHG emissions decline by 25-30% with most of the propulsion system/fuel alternatives. For those using renewable fuels (i.e., ethanol and H{sub 2} from solar energy), GHG emissions drop by 33% (H{sub 2}) and 45% (ethanol). Among urban air pollutants, urban NOX emissions decline slightly for 3X vehicles using CIDI and SIDI engines and drop substantially for fuel-cell vehicles. Urban CO emissions decline for CIDI and FCV alternatives, while VOC emissions drop significantly for all alternatives except RFG-, methanol-, and ethanol-fueled SIDI engines. With the exception of CIDI engines fueled by RFD, FT50, or B20 (which increase urban PM{sub 10} emissions by over 30%), all propulsion system/fuel alternatives reduce urban PM{sub 10} emissions. Reductions are approximately 15-20% for fuel cells and for methanol-, ethanol-, CNG-, or LPG-fueled SIDI engines. Table 3 qualitatively summarizes impacts of the 13 alternatives on capital requirements and on energy use and emissions relative to the reference scenario. The table clearly shows the trade-off between costs and benefits. For example, while H{sub 2} FCVs have the greatest incremental capital needs, they offer the largest energy and emissions benefits. On the basis of the cost and benefit changes shown, methanol and gasoline FCVs appear to have particularly promising benefits-to-costs ratios.« less

A DFT study of ethanol adsorption and decomposition on α-Al2O3(0 0 0 1) surface

NASA Astrophysics Data System (ADS)

Chiang, Hsin-Ni; Nachimuthu, Santhanamoorthi; Cheng, Ya-Chin; Damayanti, Nur Pradani; Jiang, Jyh-Chiang

2016-02-01

Ethanol adsorption and decomposition on the clean α-Al2O3(0 0 0 1) surface have been systematically investigated by density functional theory calculations. The nature of the surface-ethanol bonding has studied through the density of states (DOS) and the electron density difference (EDD) contour plots. The DOS patterns confirm that the lone pair electrons of EtOH are involved in the formation of a surface Alsbnd O dative bond and the EDD plots provide evidences for the bond weakening/forming, which are consistent with the DOS analysis. Our ethanol decomposition results indicate that ethanol dehydration to ethylene (CH3CH2OH(a) → C2H4(g) + OH(a) + H(a)), is the main reaction pathway with the energy barrier of 1.46 eV. Although the cleavage of the hydroxyl group of ethanol has lower energy barrier, the further decomposition of ethoxy owns much higher energy barrier.

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.

Sodium Hydroxide Pretreatment of Switchgrass for Ethanol Production

USDA-ARS?s Scientific Manuscript database

Lignocellulose-to-ethanol conversion is a promising technology to supplement corn-based ethanol production. However, the recalcitrant structure of lignocellulosic material is a major obstacle to the efficient conversion. To improve the enzymatic digestibility of switchgrass for the fermentable sugar...

Progress in passive solar energy systems. Volume 8. Part 1

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

Hayes, J.; Andrejko, D.A.

1983-01-01

This book presents the papers given at a conference sponsored by the US DOE, the Solar Energy Research Institute, SolarVision, Inc., and the Southern California Solar Energy Society. The topics considered at the conference included sizing solar energy systems for agricultural applications, a farm scale ethanol production plant, the EEC wind energy RandD program, the passive solar performance assessment of an earth-sheltered house, the ARCO 1 MW photovoltaic power plant, the performance of a dendritic web photovoltaic module, second generation point focused concentrators, linear fresnel lens concentrating photovoltaic collectors, photovoltaic conversion efficiency, amorphous silicon thin film solar cells, a photovoltaicmore » system for a shopping center, photovoltaic power generation for the utility industry, spectral solar radiation, and the analysis of insolation data.« less

Tradeoffs and Synergies between biofuel production and large solar infrastructure in deserts.

PubMed

Ravi, Sujith; Lobell, David B; Field, Christopher B

2014-01-01

Solar energy installations in deserts are on the rise, fueled by technological advances and policy changes. Deserts, with a combination of high solar radiation and availability of large areas unusable for crop production are ideal locations for large solar installations. However, for efficient power generation, solar infrastructures use large amounts of water for construction and operation. We investigated the water use and greenhouse gas (GHG) emissions associated with solar installations in North American deserts in comparison to agave-based biofuel production, another widely promoted potential energy source from arid systems. We determined the uncertainty in our analysis by a Monte Carlo approach that varied the most important parameters, as determined by sensitivity analysis. We considered the uncertainty in our estimates as a result of variations in the number of solar modules ha(-1), module efficiency, number of agave plants ha(-1), and overall sugar conversion efficiency for agave. Further, we considered the uncertainty in revenue and returns as a result of variations in the wholesale price of electricity and installation cost of solar photovoltaic (PV), wholesale price of agave ethanol, and cost of agave cultivation and ethanol processing. The life-cycle analyses show that energy outputs and GHG offsets from solar PV systems, mean energy output of 2405 GJ ha(-1) year(-1) (5 and 95% quantile values of 1940-2920) and mean GHG offsets of 464 Mg of CO2 equiv ha(-1) year(-1) (375-562), are much larger than agave, mean energy output from 206 (171-243) to 61 (50-71) GJ ha(-1) year(-1) and mean GHG offsets from 18 (14-22) to 4.6 (3.7-5.5) Mg of CO2 equiv ha(-1) year(-1), depending upon the yield scenario of agave. Importantly though, water inputs for cleaning solar panels and dust suppression are similar to amounts required for annual agave growth, suggesting the possibility of integrating the two systems to maximize the efficiency of land and water use to produce both electricity and liquid fuel. A life-cycle analysis of a hypothetical colocation indicated higher returns per m(3) of water used than either system alone. Water requirements for energy production were 0.22 L MJ(-1) (0.28-0.19) and 0.42 L MJ(-1) (0.52-0.35) for solar PV-agave (baseline yield) and solar PV-agave (high yield), respectively. Even though colocation may not be practical in all locations, in some water-limited areas, colocated solar PV-agave systems may provide attractive economic incentives in addition to efficient land and water use.

Unexpected methyl migrations of ethanol dimer under synchrotron VUV radiation

NASA Astrophysics Data System (ADS)

Xiao, Weizhan; Hu, Yongjun; Li, Weixing; Guan, Jiwen; Liu, Fuyi; Shan, Xiaobin; Sheng, Liusi

2015-01-01

While methyl transfer is well known to occur in the enzyme- and metal-catalyzed reactions, the methyl transfer in the metal-free organic molecules induced by the photon ionization has been less concerned. Herein, vacuum ultraviolet single photon ionization and dissociation of ethanol dimer are investigated with synchrotron radiation photoionization mass spectroscopy and theoretical methods. Besides the protonated clusters cation (C2H5OH) ṡ H+ (m/z = 47) and the β-carbon-carbon bond cleavage fragment CH2O ṡ (C2H5OH)H+ (m/z = 77), the measured mass spectra revealed that a new fragment (C2H5OH) ṡ (CH3)+ (m/z = 61) appeared at the photon energy of 12.1 and 15.0 eV, where the neutral dimer could be vertically ionized to higher ionic state. Thereafter, the generated carbonium ions are followed by a Wagner-Meerwein rearrangement and then dissociate to produce this new fragment, which is considered to generate after surmounting a few barriers including intra- and inter-molecular methyl migrations by the aid of theoretical calculations. The appearance energy of this new fragment is measured as 11.55 ± 0.05 eV by scanning photoionization efficiency curve. While the signal intensity of fragment m/z = 61 starts to increase, the fragments m/z = 47 and 77 tend to slowly incline around 11.55 eV photon energy. This suggests that the additional fragment channels other than (C2H5OH) ṡ H+ and CH2O ṡ (C2H5OH)H+ have also been opened, which consume some dimer cations. The present report provides a clear description of the photoionization and dissociation processes of the ethanol dimer in the range of the photon energy 12-15 eV.

Renewable energy recovery through selected industrial wastes

NASA Astrophysics Data System (ADS)

Zhang, Pengchong

Typically, industrial waste treatment costs a large amount of capital, and creates environmental concerns as well. A sound alternative for treating these industrial wastes is anaerobic digestion. This technique reduces environmental pollution, and recovers renewable energy from the organic fraction of those selected industrial wastes, mostly in the form of biogas (methane). By applying anaerobic technique, selected industrial wastes could be converted from cash negative materials into economic energy feed stocks. In this study, three kinds of industrial wastes (paper mill wastes, brown grease, and corn-ethanol thin stillage) were selected, their performance in the anaerobic digestion system was studied and their applicability was investigated as well. A pilot-scale system, including anaerobic section (homogenization, pre-digestion, and anaerobic digestion) and aerobic section (activated sludge) was applied to the selected waste streams. The investigation of selected waste streams was in a gradually progressive order. For paper mill effluents, since those effluents contain a large amount of recalcitrant or toxic compounds, the anaerobic-aerobic system was used to check its treatability, including organic removal efficiency, substrate utilization rate, and methane yield. The results showed the selected effluents were anaerobically treatable. For brown grease, as it is already well known as a treatable substrate, a high rate anaerobic digester were applied to check the economic effect of this substrate, including methane yield and substrate utilization rate. These data from pilot-scale experiment have the potential to be applied to full-scale plant. For thin stillage, anaerobic digestion system has been incorporated to the traditional ethanol making process as a gate-to-gate process. The performance of anaerobic digester was applied to the gate-to-gate life-cycle analysis to estimate the energy saving and industrial cost saving in a typical ethanol plant.

Cassava: a basic energy source in the tropics

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

Cock, J.H.

1982-11-19

Cassava (Manihot esculenta) is the fourth most important source of food energy in the tropics. More than two-thirds of the total production of this crop is used as food for humans, with lesser amounts being used for animal feed and industrial purposes. The ingestion of high levels of cassava has been associated with chronic cyanide toxicity in parts of Africa, but this appears to be related to inadequate processing of the root and poor overall nutrition. Although cassava is not a complete food it is important as a cheap source of calories. The crop has a high yield potential undermore » good conditions, and compared to other crops it excels under suboptimal conditions, thus offering the possibility of using marginal land to increase total agricultural production. Breeding programs that bring together germ plasm from different regions coupled with improved agronomic practices can markedly increase yields. The future demand for fresh cassava may depend on improved storage methods. The markets for cassava as a substitute for cereal flours in bakery products and as an energy source in animal feed rations are likely to expand. The use of cassava as a source of ethanol for fuel depends on finding an efficient source of energy for distillation or an improved method of separating ethanol from water. 7 figures, 8 tables.« less

Cassava: a basic energy source in the tropics.

PubMed

Cock, J H

1982-11-19

Cassava (Manihot esculenta) is the fourth most important source of food energy in the tropics. More than two-thirds of the total production of this crop is used as food for humans, with lesser amounts being used for animal feed and industrial purposes. The ingestion of high levels of cassava has been associated with chronic cyanide toxicity in parts of Africa, but this appears to be related to inadequate processing of the root and poor overall nutrition. Although cassava is not a complete food it is important as a cheap source of calories. The crop has a high yield potential under good conditions, and compared to other crops it excels under suboptimal conditions, thus offering the possibility of using marginal land to increase total agricultural production. Breeding programs that bring together germ plasm from different regions coupled with improved agronomic practices can markedly increase yields. The future demand for fresh cassava may depend on improved storage methods. The markets for cassava as a substitute for cereal flours in bakery products and as an energy source in animal feed rations are likely to expand. The use of cassava as a source of ethanol for fuel depends on finding an efficient source of energy for distillation or an improved method of separating ethanol from water.

Enhanced energy recovery from cassava ethanol wastewater through sequential dark hydrogen, photo hydrogen and methane fermentation combined with ammonium removal.

PubMed

Lin, Richen; Cheng, Jun; Yang, Zongbo; Ding, Lingkan; Zhang, Jiabei; Zhou, Junhu; Cen, Kefa

2016-08-01

Cassava ethanol wastewater (CEW) was subjected to sequential dark H2, photo H2 and CH4 fermentation to maximize H2 production and energy yield. A relatively low H2 yield of 23.6mL/g soluble chemical oxygen demand (CODs) was obtained in dark fermentation. To eliminate the inhibition of excessive NH4(+) on sequential photo fermentation, zeolite was used to remove NH4(+) in residual dark solution (86.5% removal efficiency). The treated solution from 5gCODs/L of CEW achieved the highest photo H2 yield of 369.7mL/gCODs, while the solution from 20gCODs/L gave the lowest yield of 259.6mL/gCODs. This can be explained that photo H2 yield was correlated to soluble metabolic products (SMPs) yield in dark fermentation, and specific SMPs yield decreased from 38.0 to 18.1mM/g CODs. The total energy yield significantly increased to 8.39kJ/gCODs by combining methanogenesis with a CH4 yield of 117.9mL/gCODs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Dimethyl ether (DME) as an alternative fuel

NASA Astrophysics Data System (ADS)

Semelsberger, Troy A.; Borup, Rodney L.; Greene, Howard L.

With ever growing concerns on environmental pollution, energy security, and future oil supplies, the global community is seeking non-petroleum based alternative fuels, along with more advanced energy technologies (e.g., fuel cells) to increase the efficiency of energy use. The most promising alternative fuel will be the fuel that has the greatest impact on society. The major impact areas include well-to-wheel greenhouse gas emissions, non-petroleum feed stocks, well-to-wheel efficiencies, fuel versatility, infrastructure, availability, economics, and safety. Compared to some of the other leading alternative fuel candidates (i.e., methane, methanol, ethanol, and Fischer-Tropsch fuels), dimethyl ether appears to have the largest potential impact on society, and should be considered as the fuel of choice for eliminating the dependency on petroleum. DME can be used as a clean high-efficiency compression ignition fuel with reduced NO x, SO x, and particulate matter, it can be efficiently reformed to hydrogen at low temperatures, and does not have large issues with toxicity, production, infrastructure, and transportation as do various other fuels. The literature relevant to DME use is reviewed and summarized to demonstrate the viability of DME as an alternative fuel.

Water Footprints of Cassava- and Molasses-Based Ethanol Production in Thailand

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

Mangmeechai, Aweewan, E-mail: aweewan.m@nida.ac.th; Pavasant, Prasert

The Thai government has been promoting renewable energy as well as stimulating the consumption of its products. Replacing transport fuels with bioethanol will require substantial amounts of water and enhance water competition locally. This study shows that the water footprint (WF) of molasses-based ethanol is less than that of cassava-based ethanol. The WF of molasses-based ethanol is estimated to be in the range of 1,510-1,990 L water/L ethanol, while that of cassava-based ethanol is estimated at 2,300-2,820 L water/L ethanol. Approximately 99% of the water in each of these WFs is used to cultivate crops. Ethanol production requires not onlymore » substantial amounts of water but also government interventions because it is not cost competitive. In Thailand, the government has exploited several strategies to lower ethanol prices such as oil tax exemptions for consumers, cost compensation for ethanol producers, and crop price assurances for farmers. For the renewable energy policy to succeed in the long run, the government may want to consider promoting molasses-based ethanol production as well as irrigation system improvements and sugarcane yield-enhancing practices, since molasses-based ethanol is more favorable than cassava-based ethanol in terms of its water consumption, chemical fertilizer use, and production costs.« less

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.

Low grade bioethanol for fuel mixing on gasoline engine using distillation process

NASA Astrophysics Data System (ADS)

Abikusna, Setia; Sugiarto, Bambang; Suntoro, Dedi; Azami

2017-03-01

Utilization of renewable energy in Indonesia is still low, compared to 34% oil, 20% coal and 20% gas, utilization of energy sources for water 3%, geothermal 1%, 2% biofuels, and biomass 20%. Whereas renewable energy sources dwindling due to the increasing consumption of gasoline as a fuel. It makes us have to look for alternative renewable energy, one of which is bio ethanol. Several studies on the use of ethanol was done to the researchers. Our studies using low grade bio ethanol which begins with the disitillation independently utilize flue gas heat at compact distillator, produces high grade bio ethanol and ready to be mixed with gasoline. Stages of our study is the compact distillator design of the motor dynamic continued with good performance and emission testing and ethanol distilled. Some improvement is made is through the flue gas heat control mechanism in compact distillator using gate valve, at low, medium, and high speed engine. Compact distillator used is kind of a batch distillation column. Column design process using the shortcut method, then carried the tray design to determine the overall geometry. The distillation is done by comparing the separator with a tray of different distances. As well as by varying the volume of the feed and ethanol levels that will feed distilled. In this study, we analyzed the mixing of ethanol through variation between main jet and pilot jet in the carburetor separately interchangeably with gasoline. And finally mixing mechanism bio ethanol with gasoline improved with fuel mixer for performance.

PERSPECTIVE: Learning from the Brazilian biofuel experience

NASA Astrophysics Data System (ADS)

Wang, Michael

2006-11-01

In the article `The ethanol program in Brazil' [1] José Goldemberg summarizes the key features of Brazil's sugarcane ethanol program—the most successful biofuel program in the world so far. In fact, as of 2005, Brazil was the world's largest producer of fuel ethanol. In addition to providing 40% of its gasoline market with ethanol, Brazil exports a significant amount of ethanol to Europe, Japan, and the United States. The success of the program is attributed to a variety of factors, including supportive governmental policies and favorable natural conditions (such as a tropical climate with abundant rainfall and high temperatures). As the article points out, in the early stages of the Brazilian ethanol program, the Brazilian government provided loans to sugarcane growers and ethanol producers (in most cases, they are the same people) to encourage sugarcane and ethanol production. Thereafter, ethanol prices were regulated to ensure that producers can economically sustain production and consumers can benefit from using ethanol. Over time, Brazil was able to achieve a price for ethanol that is lower than that for gasoline, on the basis of energy content. This lower cost is largely driving the widespread use of ethanol instead of gasoline by consumers in Brazil. In the United States, if owners of E85 flexible-fuel vehicles (FFVs) are expected to use E85 instead of gasoline in their FFVs, E85 will have to be priced competitively against gasoline on an energy-content basis. Compared with corn-based or sugar beet-based ethanol, Brazil's sugarcane-based ethanol yields considerably more favorable results in terms of energy balance and reductions in greenhouse gas emissions. These results are primarily due to (i) the dramatic increase of sugarcane yield in Brazil in the past 25 years and (ii) the use of bagasse instead of fossil fuels in ethanol plants to provide the heat needed for ethanol plant operations and to generate electricity for export to electric grids. Advancements in technology associated with both sugarcane farming and ethanol production have definitely played an important role in yielding the significant benefits associated with sugarcane ethanol. The United States produced about 4 billion gallons of ethanol from corn in 2005. Production was expected to increase to about 5 billion gallons by 2006. Corn-based ethanol achieves moderate reductions in greenhouse gas emissions. In the long run, the great potential of fuel ethanol lies in its production from cellulosic biomass, which is abundant in many regions of the world and can yield much greater reductions in greenhouse gas emissions and energy benefits. Figure 1 presents reductions in greenhouse emissions of several ethanol production pathways that were evaluated at the Argonne National Laboratory. Bagasse, a cellulosic biomass type already available in sugarcane ethanol plants, will certainly offer an opportunity for economically co-producing cellulosic ethanol and sugarcane ethanol in existing sugarcane ethanol plants. Greenhouse gas emissions per million Btu of gasoline and ethanol produced and used Figure 1. Greenhouse gas emissions per million Btu of gasoline and ethanol produced and used. Despite the encouraging progress of Brazil's ethanol program some issues will still need to be addressed. Figure 4 of [1] shows a significant drop in ethanol production in the 2000/2001 season. A steady supply of ethanol will be a key factor for the success of a fuel ethanol program. Consumers are not going to tolerate fluctuations in ethanol production. Instead, they will turn to conventional fuels for fueling their FFVs as a result of supply fluctuations, which can be detrimental to the success of the ethanol program. In addition to this, other environmental effects of biofuels in general, and sugarcane ethanol in particular, need to be assessed. Some have debated and speculated that Brazil's sugarcane ethanol program has caused (i) soil erosion and biodiversity problems by converting rainforests into sugarcane plantations and (ii) local air pollution problems as a result of burning in plantations before harvest. Also, as interest in biofuels heightens worldwide, environment-conscious practices are needed to avoid adverse environmental effects of biofuel production and use. For instance, if feedstock production (sugarcane in Brazil, corn in the United States, and palm oil in Malaysia [for biodiesel production]) moves into virgin or marginal land, carbon in both soil and vegetation could be decreased and diminish the benefits associated with biofuels, and cause other environmental problems, such as soil erosion. Societies need to pay close attention to these potential detrimental environmental effects to ensure that biofuel production will, indeed, be on a sustainable path. © US Government References [1] Goldemberg J 2006 The ethanol program in Brazil Environ. Res Lett. 1 014008 (doi:10.1088/1748-9326/1/1/014008) Photo of Michael Wang Michael Wang has been working in the Center for Transportation Research of Argonne National Laboratory since 1991. He is the manager of the Systems Assessment Section in the center which evaluates energy and emission effects of advanced vehicle technologies and new transportation fuels. He developed the GREET (Greenhouse gases, Regulated Emissions, and Energy use in Transportation) model, with which he has conducted several major studies for government agencies and industries. Since 1996, he has examined energy and emission benefits of bio-ethanol. His results for bio-ethanol have been cited by many. Michael Wang received his PhD in environmental science from University of California at Davis.

Ethanol and biogas production after steam pretreatment of corn stover with or without the addition of sulphuric acid

PubMed Central

2013-01-01

Background Lignocellulosic biomass, such as corn stover, is a potential raw material for ethanol production. One step in the process of producing ethanol from lignocellulose is enzymatic hydrolysis, which produces fermentable sugars from carbohydrates present in the corn stover in the form of cellulose and hemicellulose. A pretreatment step is crucial to achieve efficient conversion of lignocellulosic biomass to soluble sugars, and later ethanol. This study has investigated steam pretreatment of corn stover, with and without sulphuric acid as catalyst, and examined the effect of residence time (5–10 min) and temperature (190–210°C) on glucose and xylose recovery. The pretreatment conditions with and without dilute acid that gave the highest glucose yield were then used in subsequent experiments. Materials pretreated at the optimal conditions were subjected to simultaneous saccharification and fermentation (SSF) to produce ethanol, and remaining organic compounds were used to produce biogas by anaerobic digestion (AD). Results The highest glucose yield achieved was 86%, obtained after pretreatment at 210°C for 10 minutes in the absence of catalyst, followed by enzymatic hydrolysis. The highest yield using sulphuric acid, 78%, was achieved using pretreatment at 200°C for 10 minutes. These two pretreatment conditions were investigated using two different process configurations. The highest ethanol and methane yields were obtained from the material pretreated in the presence of sulphuric acid. The slurry in this case was split into a solid fraction and a liquid fraction, where the solid fraction was used to produce ethanol and the liquid fraction to produce biogas. The total energy recovery in this case was 86% of the enthalpy of combustion energy in corn stover. Conclusions The highest yield, comprising ethanol, methane and solids, was achieved using pretreatment in the presence of sulphuric acid followed by a process configuration in which the slurry from the pretreatment was divided into a solid fraction and a liquid fraction. The solid fraction was subjected to SSF, while the liquid fraction, together with the filtered residual from SSF, was used in AD. Using sulphuric acid in AD did not inhibit the reaction, which may be due to the low concentration of sulphuric acid used. In contrast, a pretreatment step without sulphuric acid resulted not only in higher concentrations of inhibitors, which affected the ethanol yield, but also in lower methane production. PMID:23356481

Adsorption and solvation of ethanol at the water liquid-vapor interface: a molecular dynamics study

NASA Technical Reports Server (NTRS)

Wilson, M. A.; Pohorille, A.

1997-01-01

The free energy profiles of methanol and ethanol at the water liquid-vapor interface at 310K were calculated using molecular dynamics computer simulations. Both alcohols exhibit a pronounced free energy minimum at the interface and, therefore, have positive adsorption at this interface. The surface excess was computed from the Gibbs adsorption isotherm and was found to be in good agreement with experimental results. Neither compound exhibits a free energy barrier between the bulk and the surface adsorbed state. Scattering calculations of ethanol molecules from a gas phase thermal distribution indicate that the mass accommodation coefficient is 0.98, and the molecules become thermalized within 10 ps of striking the interface. It was determined that the formation of the solvation structure around the ethanol molecule at the interface is not the rate-determining step in its uptake into water droplets. The motion of an ethanol molecule in a water lamella was followed for 30 ns. The time evolution of the probability distribution of finding an ethanol molecule that was initially located at the interface is very well described by the diffusion equation on the free energy surface.

Techno-economic evaluation of 2nd generation bioethanol production from sugar cane bagasse and leaves integrated with the sugar-based ethanol process

PubMed Central

2012-01-01

Background Bioethanol produced from the lignocellulosic fractions of sugar cane (bagasse and leaves), i.e. second generation (2G) bioethanol, has a promising market potential as an automotive fuel; however, the process is still under investigation on pilot/demonstration scale. From a process perspective, improvements in plant design can lower the production cost, providing better profitability and competitiveness if the conversion of the whole sugar cane is considered. Simulations have been performed with AspenPlus to investigate how process integration can affect the minimum ethanol selling price of this 2G process (MESP-2G), as well as improve the plant energy efficiency. This is achieved by integrating the well-established sucrose-to-bioethanol process with the enzymatic process for lignocellulosic materials. Bagasse and leaves were steam pretreated using H3PO4 as catalyst and separately hydrolysed and fermented. Results The addition of a steam dryer, doubling of the enzyme dosage in enzymatic hydrolysis, including leaves as raw material in the 2G process, heat integration and the use of more energy-efficient equipment led to a 37 % reduction in MESP-2G compared to the Base case. Modelling showed that the MESP for 2G ethanol was 0.97 US$/L, while in the future it could be reduced to 0.78 US$/L. In this case the overall production cost of 1G + 2G ethanol would be about 0.40 US$/L with an output of 102 L/ton dry sugar cane including 50 % leaves. Sensitivity analysis of the future scenario showed that a 50 % decrease in the cost of enzymes, electricity or leaves would lower the MESP-2G by about 20%, 10% and 4.5%, respectively. Conclusions According to the simulations, the production of 2G bioethanol from sugar cane bagasse and leaves in Brazil is already competitive (without subsidies) with 1G starch-based bioethanol production in Europe. Moreover 2G bioethanol could be produced at a lower cost if subsidies were used to compensate for the opportunity cost from the sale of excess electricity and if the cost of enzymes continues to fall. PMID:22502801

Phenotypic and Genetic Effects of Contrasting Ethanol Environments on Physiological and Developmental Traits in Drosophila melanogaster

PubMed Central

Castañeda, Luis E.; Nespolo, Roberto F.

2013-01-01

A central problem in evolutionary physiology is to understand the relationship between energy metabolism and fitness-related traits. Most attempts to do so have been based on phenotypic correlations that are not informative for the evolutionary potential of natural populations. Here, we explored the effect of contrasting ethanol environments on physiological and developmental traits, their genetic (co)variances and genetic architecture in Drosophila melanogaster. Phenotypic and genetic parameters were estimated in two populations (San Fernando and Valdivia, Chile), using a half-sib family design where broods were split into ethanol-free and ethanol-supplemented conditions. Our findings show that metabolic rate, body mass and development times were sensitive (i.e., phenotypic plasticity) to ethanol conditions and dependent on population origin. Significant heritabilities were found for all traits, while significant genetic correlations were only found between larval and total development time and between development time and metabolic rate for flies of the San Fernando population developed in ethanol-free conditions. Posterior analyses indicated that the G matrices differed between ethanol conditions for the San Fernando population (mainly explained by differences in genetic (co)variances of developmental traits), whereas the Valdivia population exhibited similar G matrices between ethanol conditions. Our findings suggest that ethanol-free environment increases the energy available to reduce development time. Therefore, our results indicate that environmental ethanol could modify the process of energy allocation, which could have consequences on the evolutionary response of natural populations of D. melanogaster. PMID:23505567

Valorization of kitchen biowaste for ethanol production via simultaneous saccharification and fermentation using co-cultures of the yeasts Saccharomyces cerevisiae and Pichia stipitis.

PubMed

Ntaikou, Ioanna; Menis, Nikolaos; Alexandropoulou, Maria; Antonopoulou, Georgia; Lyberatos, Gerasimos

2018-04-30

The biotransformation of the pre-dried and shredded organic fraction of kitchen waste to ethanol was investigated, via co-cultures of the yeasts Saccharomyces cerevisiae and Pichia stipitis (Scheffersomyces stipitis). Preliminary experiments with synthetic media were performed, in order to investigate the effect of different operational parameters on the ethanol production efficiency of the co-culture. The control of the pH and the supplementation with organic nitrogen were shown to be key factors for the optimization of the process. Subsequently, the ethanol production efficiency from the waste was assessed via simultaneous saccharification and fermentation experiments. Different loadings of cellulolytic enzymes and mixtures of cellulolytic with amylolytic enzymatic blends were tested in order to enhance the substrate conversion efficiency. It was further shown that for solids loading up to 40% waste on dry mass basis, corresponding to 170 g.L -1 initial concentration of carbohydrates, no substrate inhibition occurred, and ethanol concentration up to 45 g.L -1 was achieved. Copyright © 2018 Elsevier Ltd. All rights reserved.

Oxygen permeation through Nafion 117 membrane and its impact on efficiency of polymer membrane ethanol fuel cell

NASA Astrophysics Data System (ADS)

Jablonski, Andrzej; Kulesza, Pawel J.; Lewera, Adam

2011-05-01

We investigate oxygen permeation through Nafion 117 membrane in a direct ethanol fuel cell and elucidate how it affects the fuel cell efficiency. An obvious symptom of oxygen permeation is the presence of significant amounts of acetaldehyde and acetic acid in the mixture leaving anode when no current was drawn from the fuel cell (i.e. under the open circuit conditions). This parasitic process severely lowers efficiency of the fuel cell because ethanol is found to be directly oxidized on the surface of catalyst by oxygen coming through membrane from cathode in the absence of electric current flowing in the external circuit. Three commonly used carbon-supported anode catalysts are investigated, Pt, Pt/Ru and Pt/Sn. Products of ethanol oxidation are determined qualitatively and quantitatively at open circuit as a function of temperature and pressure, and we aim at determining whether the oxygen permeation or the catalyst's activity limits the parasitic ethanol oxidation. Our results strongly imply the need to develop more selective membranes that would be less oxygen permeable.

Direct ethanol production from barley beta-glucan by sake yeast displaying Aspergillus oryzae beta-glucosidase and endoglucanase.

PubMed

Kotaka, Atsushi; Bando, Hiroki; Kaya, Masahiko; Kato-Murai, Michiko; Kuroda, Kouichi; Sahara, Hiroshi; Hata, Yoji; Kondo, Akihiko; Ueda, Mitsuyoshi

2008-06-01

Three beta-glucosidase- and two endoglucanase-encoding genes were cloned from Aspergillus oryzae, and their gene products were displayed on the cell surface of the sake yeast, Saccharomyces cerevisiae GRI-117-UK. GRI-117-UK/pUDB7 displaying beta-glucosidase AO090009000356 showed the highest activity against various substrates and efficiently produced ethanol from cellobiose. On the other hand, GRI-117-UK/pUDCB displaying endoglucanase AO090010000314 efficiently degraded barley beta-glucan to glucose and smaller cellooligosaccharides. GRI-117-UK/pUDB7CB codisplaying both beta-glucosidase AO090009000356 and endoglucanase AO090010000314 was constructed. When direct ethanol fermentation from 20 g/l barley beta-glucan as a model substrate was performed with the codisplaying strain, the ethanol concentration reached 7.94 g/l after 24 h of fermentation. The conversion ratio of ethanol from beta-glucan was 69.6% of the theoretical ethanol concentration produced from 20 g/l barley beta-glucan. These results showed that sake yeast displaying A. oryzae cellulolytic enzymes can be used to produce ethanol from cellulosic materials. Our constructs have higher ethanol production potential than the laboratory constructs previously reported.

Helically agitated mixing in dry dilute acid pretreatment enhances the bioconversion of corn stover into ethanol

PubMed Central

2014-01-01

Background Dry dilute acid pretreatment at extremely high solids loading of lignocellulose materials demonstrated promising advantages of no waste water generation, less sugar loss, and low steam consumption while maintaining high hydrolysis yield. However, the routine pretreatment reactor without mixing apparatus was found not suitable for dry pretreatment operation because of poor mixing and mass transfer. In this study, helically agitated mixing was introduced into the dry dilute acid pretreatment of corn stover and its effect on pretreatment efficiency, inhibitor generation, sugar production, and bioconversion efficiency through simultaneous saccharification and ethanol fermentation (SSF) were evaluated. Results The overall cellulose conversion taking account of cellulose loss in pretreatment was used to evaluate the efficiency of pretreatment. The two-phase computational fluid dynamics (CFD) model on dry pretreatment was established and applied to analyze the mixing mechanism. The results showed that the pretreatment efficiency was significantly improved and the inhibitor generation was reduced by the helically agitated mixing, compared to the dry pretreatment without mixing: the ethanol titer and yield from cellulose in the SSF reached 56.20 g/L and 69.43% at the 30% solids loading and 15 FPU/DM cellulase dosage, respectively, corresponding to a 26.5% increase in ethanol titer and 17.2% increase in ethanol yield at the same fermentation conditions. Conclusions The advantage of helically agitated mixing may provide a prototype of dry dilute acid pretreatment processing for future commercial-scale production of cellulosic ethanol. PMID:24387051

Mathematical model for the analysis of structure and optimal operational parameters of a solid oxide fuel cell generator

NASA Astrophysics Data System (ADS)

Coralli, Alberto; Villela de Miranda, Hugo; Espiúca Monteiro, Carlos Felipe; Resende da Silva, José Francisco; Valadão de Miranda, Paulo Emílio

2014-12-01

Solid oxide fuel cells are globally recognized as a very promising technology in the area of highly efficient electricity generation with a low environmental impact. This technology can be advantageously implemented in many situations in Brazil and it is well suited to the use of ethanol as a primary energy source, an important feature given the highly developed Brazilian ethanol industry. In this perspective, a simplified mathematical model is developed for a fuel cell and its balance of plant, in order to identify the optimal system structure and the most convenient values for the operational parameters, with the aim of maximizing the global electric efficiency. In this way it is discovered the best operational configuration for the desired application, which is the distributed generation in the concession area of the electricity distribution company Elektro. The data regarding this configuration are required for the continuation of the research project, i.e. the development of a prototype, a cost analysis of the developed system and a detailed perspective of the market opportunities in Brazil.

Retrieval of Au, Ag, Cu precious metals coupled with electric energy production via an unconventional coupled redox fuel cell reactor.

PubMed

Zhang, Hui-Min; Fan, Zheng; Xu, Wei; Feng, Xiao; Wu, Zu-Cheng

2017-09-15

The recovery of heavy metals from aqueous solutions or e-wastes is of upmost importance. Retrieval of Au, Ag, and Cu with electricity generation through building an ethanol-metal coupled redox fuel cells (CRFCs) is demonstrated. The cell was uniquely assembled on PdNi/C anode the electro-oxidation of ethanol takes place to give electrons and then go through the external circuit reducing metal ions to metallic on the cathode, metals are recovered. Taking an example of removal of 100mgL -1 gold in 0.5M HAc-NaAc buffer solution as the catholyte, 2.0M ethanol in 1.0M alkaline solution as the anolyte, an open circuit voltage of 1.4V, more than 96% of gold removal efficiency in 20h, and equivalent energy production of 2.0kWhkg -1 of gold can be readily achieved in this system. When gold and copper ions coexist, it was confirmed that metallic Cu is formed on the cathodic electrode later than metallic Au formation by XPS analysis. Thus, this system can achieve step by step electrodeposition of gold and copper while the two metal ions coexisting. This work develops a new approach to retrieve valuable metals from aqueous solution or e-wastes. Copyright © 2017 Elsevier B.V. All rights reserved.

[Study on the Emission Spectrum of Hydrogen Production with Microwave Discharge Plasma in Ethanol Solution].

PubMed

Sun, Bing; Wang, Bo; Zhu, Xiao-mei; Yan, Zhi-yu; Liu, Yong-jun; Liu, Hui

2016-03-01

Hydrogen is regarded as a kind of clean energy with high caloricity and non-pollution, which has been studied by many experts and scholars home and abroad. Microwave discharge plasma shows light future in the area of hydrogen production from ethanol solution, providing a new way to produce hydrogen. In order to further improve the technology and analyze the mechanism of hydrogen production with microwave discharge in liquid, emission spectrum of hydrogen production by microwave discharge plasma in ethanol solution was being studied. In this paper, plasma was generated on the top of electrode by 2.45 GHz microwave, and the spectral characteristics of hydrogen production from ethanol by microwave discharge in liquid were being studied using emission spectrometer. The results showed that a large number of H, O, OH, CH, C2 and other active particles could be produced in the process of hydrogen production from ethanol by microwave discharge in liquid. The emission spectrum intensity of OH, H, O radicals generated from ethanol is far more than that generated from pure water. Bond of O-H split by more high-energy particles from water molecule was more difficult than that from ethanol molecule, so in the process of hydrogen production by microwave discharge plasma in ethanol solution; the main source of hydrogen was the dehydrogenation and restructuring of ethanol molecules instead of water decomposition. Under the definite external pressure and temperature, the emission spectrum intensity of OH, H, O radicals increased with the increase of microwave power markedly, but the emission spectrum intensity of CH, C2 active particles had the tendency to decrease with the increase of microwave power. It indicated that the number of high energy electrons and active particles high energy electron energy increased as the increase of microwave power, so more CH, C2 active particles were split more thoroughly.

Lignocellulosic ethanol: Technology design and its impact on process efficiency.

PubMed

Paulova, Leona; Patakova, Petra; Branska, Barbora; Rychtera, Mojmir; Melzoch, Karel

2015-11-01

This review provides current information on the production of ethanol from lignocellulosic biomass, with the main focus on relationships between process design and efficiency, expressed as ethanol concentration, yield and productivity. In spite of unquestionable advantages of lignocellulosic biomass as a feedstock for ethanol production (availability, price, non-competitiveness with food, waste material), many technological bottlenecks hinder its wide industrial application and competitiveness with 1st generation ethanol production. Among the main technological challenges are the recalcitrant structure of the material, and thus the need for extensive pretreatment (usually physico-chemical followed by enzymatic hydrolysis) to yield fermentable sugars, and a relatively low concentration of monosaccharides in the medium that hinder the achievement of ethanol concentrations comparable with those obtained using 1st generation feedstocks (e.g. corn or molasses). The presence of both pentose and hexose sugars in the fermentation broth, the price of cellulolytic enzymes, and the presence of toxic compounds that can inhibit cellulolytic enzymes and microbial producers of ethanol are major issues. In this review, different process configurations of the main technological steps (enzymatic hydrolysis, fermentation of hexose/and or pentose sugars) are discussed and their efficiencies are compared. The main features, benefits and drawbacks of simultaneous saccharification and fermentation (SSF), simultaneous saccharification and fermentation with delayed inoculation (dSSF), consolidated bioprocesses (CBP) combining production of cellulolytic enzymes, hydrolysis of biomass and fermentation into one step, together with an approach combining utilization of both pentose and hexose sugars are discussed and compared with separate hydrolysis and fermentation (SHF) processes. The impact of individual technological steps on final process efficiency is emphasized and the potential for use of immobilized biocatalysts is considered. Copyright © 2014 Elsevier Inc. All rights reserved.

Ethanol Basics

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

None

2015-01-30

Ethanol is a widely-used, domestically-produced renewable fuel made from corn and other plant materials. More than 96% of gasoline sold in the United States contains ethanol. Learn more about this alternative fuel in the Ethanol Basics Fact Sheet, produced by the U.S. Department of Energy's Clean Cities program.

Combined algal processing: A novel integrated biorefinery process to produce algal biofuels and bioproducts

DOE PAGES

Dong, Tao; Knoshaug, Eric P.; Davis, Ryan; ...

2016-01-18

Here, the development of an integrated biorefinery process capable of producing multiple products is crucial for commercialization of microalgal biofuel production. Dilute acid pretreatment has been demonstrated as an efficient approach to utilize algal biomass more fully, by hydrolyzing microalgal carbohydrates into fermentable sugars, while making the lipids more extractable, and a protein fraction available for other products. Previously, we have shown that sugar-rich liquor could be separated from solid residue by solid-liquid separation (SLS) to produce ethanol via fermentation. However, process modeling has revealed that approximately 37% of the soluble sugars were lost in the solid cake after themore » SLS. Herein, a Combined Algal Processing (CAP) approach with a simplified configuration has been developed to improve the total energy yield. In CAP, whole algal slurry after acid pretreatment is directly used for ethanol fermentation. The ethanol and microalgal lipids can be sequentially recovered from the fermentation broth by thermal treatment and solvent extraction. Almost all the monomeric fermentable sugars can be utilized for ethanol production without compromising the lipid recovery. The techno-economic analysis (TEA) indicates that the CAP can reduce microalgal biofuel cost by $0.95 per gallon gasoline equivalent (GGE), which is a 9% reduction compared to the previous biorefinery scenario.« less

Development of a dedicated ethanol ultra-low emission vehicle (ULEV): Final report

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

Dodge, L.; Bourn, G.; Callahan, T.

The objective of this project was to develop a commercially competitive vehicle powered by ethanol (or an ethanol blend) that can meet California`s ultra-low emission vehicle (ULEV) standards and equivalent corporate average fuel economy (CAFE) energy efficiency for a light-duty passenger car application. The definition of commercially competitive is independent of fuel cost, but does include technical requirements for competitive power, performance, refueling times, vehicle range, driveability, fuel handling safety, and overall emissions performance. This report summarizes the fourth and final phase of this project, and also the overall project. The focus of this report is the technology used tomore » develop a dedicated ethanol-fueled ULEV, and the emissions results documenting ULV performance. Some of the details for the control system and hardware changes are presented in two appendices that are SAE papers. The demonstrator vehicle has a number of advanced technological features, but it is currently configured with standard original equipment manufacturer (OEM) under-engine catalysts. Close-coupled catalysts would improve emissions results further, but no close-coupled catalysts were available for this testing. Recently, close-coupled catalysts were obtained, but installation and testing will be performed in the future. This report also briefly summarizes work in several other related areas that supported the demonstrator vehicle work.« less

Copper-palladium core-shell as an anode in a multi-fuel membraneless nanofluidic fuel cell: toward a new era of small energy conversion devices.

PubMed

Maya-Cornejo, J; Ortiz-Ortega, E; Álvarez-Contreras, L; Arjona, N; Guerra-Balcázar, M; Ledesma-García, J; Arriaga, L G

2015-02-14

A membraneless nanofluidic fuel cell with flow-through electrodes that works with several fuels (individually or mixed): methanol, ethanol, glycerol and ethylene-glycol in alkaline media is presented. For this application, an efficient Cu@Pd electrocatalyst was synthesized and tested, resulting outstanding performance until now reported, opening the possibility of power nano-devices for multi-uses purposes, regardless of fuel re-charge employed.

What can be Learned from Silage Breeding Programs?

NASA Astrophysics Data System (ADS)

Lorenz, Aaron J.; Coors, James G.

Improving the quality of cellulosic ethanol feedstocks through breeding and genetic manipulation could significantly impact the economics of this industry. Attaining this will require comprehensive and rapid characterization of large numbers of samples. There are many similarities between improving corn silage quality for dairy production and improving feedstock quality for cellulosic ethanol. It was our objective to provide insight into what is needed for genetic improvement of cellulosic feedstocks by reviewing the development and operation of a corn silage breeding program. We discuss the evolving definition of silage quality and relate what we have learned about silage quality to what is needed for measuring and improving feedstock quality. In addition, repeatability estimates of corn stover traits are reported for a set of hybrids. Repeatability of theoretical ethanol potential measured by near-infrared spectroscopy is high, suggesting that this trait may be easily improved through breeding. Just as cell wall digestibility has been factored into the latest measurements of silage quality, conversion efficiency should be standardized and included in indices of feedstock quality to maximize overall, economical energy availability.

Point mutation of H3/H4 histones affects acetic acid tolerance in Saccharomyces cerevisiae.

PubMed

Liu, Xiangyong; Zhang, Xiaohua; Zhang, Zhaojie

2014-10-10

The molecular mechanism of acetic acid tolerance in yeast remains unclear despite of its importance for efficient cellulosic ethanol production. In this study, we examined the effects of histone H3/H4 point mutations on yeast acetic acid tolerance by comprehensively screening a histone H3/H4 mutant library. A total of 24 histone H3/H4 mutants (six acetic acid resistant and 18 sensitive) were identified. Compared to the wild-type strain, the histone acetic acid-resistant mutants exhibited improved ethanol fermentation performance under acetic acid stress. Genome-wide transcriptome analysis revealed that changes in the gene expression in the acetic acid-resistant mutants H3 K37A and H4 K16Q were mainly related to energy production, antioxidative stress. Our results provide novel insights into yeast acetic acid tolerance on the basis of histone, and suggest a novel approach to improve ethanol production by altering the histone H3/H4 sequences. Copyright © 2014 Elsevier B.V. All rights reserved.

Impacts of renewable fuel regulation and production on agriculture, energy, and welfare

NASA Astrophysics Data System (ADS)

McPhail, Lihong Lu

The purpose of this dissertation is to study the impact of U.S. federal renewable fuel regulations on energy and agriculture commodity markets and welfare. We consider two federal ethanol policies: the Renewable Fuel Standard (RFS) contained in the Energy Security and Independence Act of 2007 and tax credits to ethanol blenders contained in the Food, Conservation, and Energy Act of 2008. My first essay estimates the distribution of short-run impacts of changing federal ethanol policies on U.S. energy prices, agricultural commodity prices, and welfare through a stochastic partial equilibrium model of U.S. corn, ethanol, and gasoline markets. My second essay focuses on studying the price behavior of the renewable fuel credit (RFC) market, which is the mechanism developed by the Environmental Protection Agency (EPA) to meet the RFS. RFCs are a tradable, bankable, and borrowable accounting mechanism to ensure that all obligated parties use a mandated level of renewable fuel. I first develop a conceptual framework to understand how the market works and then apply stochastic dynamic programming to simulate prices for RFCs, examine the sensitivity of prices to relevant shocks, and estimate RFC option premiums. My third essay assesses the impact of policy led U.S. ethanol on the markets of global crude oil and U.S. gasoline using a structural Vector Auto Regression model of global crude oil, U.S. gasoline and ethanol markets.

Influence of *OH adsorbates on the potentiodynamics of the CO 2 generation during the electro-oxidation of ethanol

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

Yang, Guangxing; Namin, Lida M.; Aaron Deskins, N.

Direct ethanol fuel cells (DEFCs) are a promising technology for the generation of electricity via the direct conversion of ethanol into CO 2, showing higher thermodynamic efficiency and volumetric energy density than hydrogen fuel cells. However, implementation of DEFCs is hampered by the low CO 2 selectivity during the ethanol oxidation reaction (EOR). Comprehensive understanding of the electro-kinetics and reaction pathways of CO 2 generation via CC bond-breaking is not only a fundamental question for electro-catalysis, but also a key technological challenge since practical implementation of DEFC technology is contingent on its ability to selectively oxidize ethanol into CO 2more » to achieve exceptional energy density through 12-electron transfer reaction. Here, we present comprehensive in situ potentiodynamics studies of CO 2 generation during the EOR on Pt, Pt/SnO 2 and Pt/Rh/SnO 2 catalysts using a house-made electrochemical cell equipped with a CO 2 microelectrode. Highly sensitive CO 2 measurements enable the real time detection of the partial pressure of CO 2 during linear sweep voltammetry measurements, through which electro-kinetics details of CO 2 generation can be obtained. In situ CO 2 measurements provide the mechanistic understanding of potentiodynamics of the EOR, particularly the influence of *OH adsorbates on CO 2 generation rate and selectivity. Density functional theory (DFT) simulations of Pt, Pt/SnO 2, and Pt/Rh/SnO 2 surfaces clarify reaction details over these catalysts. Our results show that at low potentials, inadequate *OH adsorbates impair the removal of reaction intermediates, and thus Pt/Rh/SnO 2 exhibited the best performance toward CO 2 generation, while at high potentials, Rh sites were overwhelmingly occupied (poisoned) by *OH adsorbates, and thus Pt/SnO 2 exhibited the best performance toward CO 2 generation.« less

Ethanol Basics (Fact Sheet)

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

Not Available

2015-01-01

Ethanol is a widely-used, domestically-produced renewable fuel made from corn and other plant materials. More than 96% of gasoline sold in the United States contains ethanol. Learn more about this alternative fuel in the Ethanol Basics Fact Sheet, produced by the U.S. Department of Energy's Clean Cities program.

Analysis of Enzymatic Degradation of Cellulose Microfibrils using Quantitative Surface Plasmon Resonance Imaging

NASA Astrophysics Data System (ADS)

Reiter, Kyle; Raegen, Adam; Allen, Scott; Quirk, Amanda; Clarke, Anthony; Lipkowski, Jacek; Dutcher, John

2013-03-01

Cellulose is the largest component of biomass on Earth and, as a result, is a significant potential energy source. The production of cellulosic ethanol as a fuel source requires conversion of cellulose fibers into fermentable sugars. Increasing our understanding of the action of cellulose enzymes (cellulases) on cellulose microfibrils is an important step in developing more efficient industrial processes for the production of cellulosic ethanol. We have used a custom designed Surface Plasmon Resonance imaging (SPRi) device to study the action of cellulases from the Hypocrea jecorinasecretome on bacterial cellulose microfibrils. This has allowed us to determine the rates of action and extent of degradation of cellulose microfibrils on exposure to both individual cellulases and combinations of different classes of cellulases, which has allowed us to investigate synergistic interactions between the cellulases.

Bacteriophage application restores ethanol fermentation characteristics disrupted by Lactobacillus fermentum

USDA-ARS?s Scientific Manuscript database

Background: Contamination of corn mash by lactic acid bacteria (LAB) reduces ethanol yields and the overall efficiency of the ethanol fermentation process, and the industry relies heavily on antibiotics for contamination control. There is a need to develop alternative methods for the control of cont...

Process analysis and optimization of simultaneous saccharification and co-fermentation of ethylenediamine-pretreated corn stover for ethanol production.

PubMed

Qin, Lei; Zhao, Xiong; Li, Wen-Chao; Zhu, Jia-Qing; Liu, Li; Li, Bing-Zhi; Yuan, Ying-Jin

2018-01-01

Improving ethanol concentration and reducing enzyme dosage are main challenges in bioethanol refinery from lignocellulosic biomass. Ethylenediamine (EDA) pretreatment is a novel method to improve enzymatic digestibility of lignocellulose. In this study, simultaneous saccharification and co-fermentation (SSCF) process using EDA-pretreated corn stover was analyzed and optimized to verify the constraint factors on ethanol production. Highest ethanol concentration was achieved with the following optimized SSCF conditions at 6% glucan loading: 12-h pre-hydrolysis, 34 °C, pH 5.4, and inoculum size of 5 g dry cell/L. As glucan loading increased from 6 to 9%, ethanol concentration increased from 33.8 to 48.0 g/L, while ethanol yield reduced by 7%. Mass balance of SSCF showed that the reduction of ethanol yield with the increasing solid loading was mainly due to the decrease of glucan enzymatic conversion and xylose metabolism of the strain. Tween 20 and BSA increased ethanol concentration through enhancing enzymatic efficiency. The solid-recycled SSCF process reduced enzyme dosage by 40% (from 20 to 12 mg protein/g glucan) to achieve the similar ethanol concentration (~ 40 g/L) comparing to conventional SSCF. Here, we established an efficient SSCF procedure using EDA-pretreated biomass. Glucose enzymatic yield and yeast viability were regarded as the key factors affecting ethanol production at high solid loading. The extensive analysis of SSCF would be constructive to overcome the bottlenecks and improve ethanol production in cellulosic ethanol refinery.

Radiolysis of ethanol and ethanol-water solutions: A tool for studying bioradical reactions

NASA Astrophysics Data System (ADS)

Jore, D.; Champion, B.; Kaouadji, N.; Jay-Gerin, J.-P.; Ferradini, C.

Radiolysis of pure ethanol and ethanol-water solutions is examined in view of its relevance to the study of biological radical mechanisms. On the basis of earlier studies, a consistent reaction scheme is adopted. New data on radical yields are obtained from the radiolysis of dilute solutions of vitamins E and C in these solvents. It is shown that the radiolysis of ethanolic solutions provide an efficient tool to study radical reactions of water-insoluble biomolecules.

A metal-free electrocatalyst for carbon dioxide reduction to multi-carbon hydrocarbons and oxygenates

PubMed Central

Wu, Jingjie; Ma, Sichao; Sun, Jing; Gold, Jake I.; Tiwary, ChandraSekhar; Kim, Byoungsu; Zhu, Lingyang; Chopra, Nitin; Odeh, Ihab N.; Vajtai, Robert; Yu, Aaron Z.; Luo, Raymond; Lou, Jun; Ding, Guqiao; Kenis, Paul J. A.; Ajayan, Pulickel M.

2016-01-01

Electroreduction of carbon dioxide into higher-energy liquid fuels and chemicals is a promising but challenging renewable energy conversion technology. Among the electrocatalysts screened so far for carbon dioxide reduction, which includes metals, alloys, organometallics, layered materials and carbon nanostructures, only copper exhibits selectivity towards formation of hydrocarbons and multi-carbon oxygenates at fairly high efficiencies, whereas most others favour production of carbon monoxide or formate. Here we report that nanometre-size N-doped graphene quantum dots (NGQDs) catalyse the electrochemical reduction of carbon dioxide into multi-carbon hydrocarbons and oxygenates at high Faradaic efficiencies, high current densities and low overpotentials. The NGQDs show a high total Faradaic efficiency of carbon dioxide reduction of up to 90%, with selectivity for ethylene and ethanol conversions reaching 45%. The C2 and C3 product distribution and production rate for NGQD-catalysed carbon dioxide reduction is comparable to those obtained with copper nanoparticle-based electrocatalysts. PMID:27958290

Dry-grind processing using amylase corn and superior yeast to reduce the exogenous enzyme requirements in bioethanol production.

PubMed

Kumar, Deepak; Singh, Vijay

2016-01-01

Conventional corn dry-grind ethanol production process requires exogenous alpha and glucoamylases enzymes to breakdown starch into glucose, which is fermented to ethanol by yeast. This study evaluates the potential use of new genetically engineered corn and yeast, which can eliminate or minimize the use of these external enzymes, improve the economics and process efficiencies, and simplify the process. An approach of in situ ethanol removal during fermentation was also investigated for its potential to improve the efficiency of high-solid fermentation, which can significantly reduce the downstream ethanol and co-product recovery cost. The fermentation of amylase corn (producing endogenous α-amylase) using conventional yeast and no addition of exogenous α-amylase resulted in ethanol concentration of 4.1 % higher compared to control treatment (conventional corn using exogenous α-amylase). Conventional corn processed with exogenous α-amylase and superior yeast (producing glucoamylase or GA) with no exogenous glucoamylase addition resulted in ethanol concentration similar to control treatment (conventional yeast with exogenous glucoamylase addition). Combination of amylase corn and superior yeast required only 25 % of recommended glucoamylase dose to complete fermentation and achieve ethanol concentration and yield similar to control treatment (conventional corn with exogenous α-amylase, conventional yeast with exogenous glucoamylase). Use of superior yeast with 50 % GA addition resulted in similar increases in yield for conventional or amylase corn of approximately 7 % compared to that of control treatment. Combination of amylase corn, superior yeast, and in situ ethanol removal resulted in a process that allowed complete fermentation of 40 % slurry solids with only 50 % of exogenous GA enzyme requirements and 64.6 % higher ethanol yield compared to that of conventional process. Use of amylase corn and superior yeast in the dry-grind processing industry can reduce the total external enzyme usage by more than 80 %, and combining their use with in situ removal of ethanol during fermentation allows efficient high-solid fermentation.

Fast electrosynthesis of Fe-containing layered double hydroxide arrays toward highly efficient electrocatalytic oxidation reactions† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c5sc02417j

PubMed Central

Li, Zhenhua; An, Hongli; Wang, Zixuan; Xu, Simin; Evans, David G.; Duan, Xue

2015-01-01

A new electrochemical synthesis route was developed for the fabrication of Fe-containing layered double hydroxide (MFe-LDHs, M = Ni, Co and Li) hierarchical nanoarrays, which exhibit highly-efficient electrocatalytic performances for the oxidation reactions of several small molecules (water, hydrazine, methanol and ethanol). Ultrathin MFe-LDH nanoplatelets (200–300 nm in lateral length; 8–12 nm in thickness) perpendicular to the substrate surface are directly prepared within hundreds of seconds (<300 s) under cathodic potential. The as-obtained NiFe-LDH nanoplatelet arrays display promising behavior in the oxygen evolution reaction (OER), giving rise to a rather low overpotential (0.224 V) at 10.0 mA cm–2 with largely enhanced stability, much superior to previously reported electro-oxidation catalysts as well as the state-of-the-art Ir/C catalyst. Furthermore, the MFe-LDH nanoplatelet arrays can also efficiently catalyze several other fuel molecules’ oxidation (e.g., hydrazine, methanol and ethanol), delivering a satisfactory electrocatalytic activity and a high operation stability. In particular, this preparation method of Fe-containing LDHs is amenable to fast, effective and large-scale production, and shows promising applications in water splitting, fuel cells and other clean energy devices. PMID:29435211

Methane production by treating vinasses from hydrous ethanol using a modified UASB reactor

PubMed Central

2012-01-01

Background A modified laboratory-scale upflow anaerobic sludge blanket (UASB) reactor was used to obtain methane by treating hydrous ethanol vinasse. Vinasses or stillage are waste materials with high organic loads, and a complex composition resulting from the process of alcohol distillation. They must initially be treated with anaerobic processes due to their high organic loads. Vinasses can be considered multipurpose waste for energy recovery and once treated they can be used in agriculture without the risk of polluting soil, underground water or crops. In this sense, treatment of vinasse combines the elimination of organic waste with the formation of methane. Biogas is considered as a promising renewable energy source. The aim of this study was to determine the optimum organic loading rate for operating a modified UASB reactor to treat vinasse generated in the production of hydrous ethanol from sugar cane molasses. Results The study showed that chemical oxygen demand (COD) removal efficiency was 69% at an optimum organic loading rate (OLR) of 17.05 kg COD/m3-day, achieving a methane yield of 0.263 m3/kg CODadded and a biogas methane content of 84%. During this stage, effluent characterization presented lower values than the vinasse, except for potassium, sulfide and ammonia nitrogen. On the other hand, primers used to amplify the 16S-rDNA genes for the domains Archaea and Bacteria showed the presence of microorganisms which favor methane production at the optimum organic loading rate. Conclusions The modified UASB reactor proposed in this study provided a successful treatment of the vinasse obtained from hydrous ethanol production. Methanogen groups (Methanobacteriales and Methanosarcinales) detected by PCR during operational optimum OLR of the modified UASB reactor, favored methane production. PMID:23167984

Methane production by treating vinasses from hydrous ethanol using a modified UASB reactor.

PubMed

España-Gamboa, Elda I; Mijangos-Cortés, Javier O; Hernández-Zárate, Galdy; Maldonado, Jorge A Domínguez; Alzate-Gaviria, Liliana M

2012-11-21

A modified laboratory-scale upflow anaerobic sludge blanket (UASB) reactor was used to obtain methane by treating hydrous ethanol vinasse. Vinasses or stillage are waste materials with high organic loads, and a complex composition resulting from the process of alcohol distillation. They must initially be treated with anaerobic processes due to their high organic loads. Vinasses can be considered multipurpose waste for energy recovery and once treated they can be used in agriculture without the risk of polluting soil, underground water or crops. In this sense, treatment of vinasse combines the elimination of organic waste with the formation of methane. Biogas is considered as a promising renewable energy source. The aim of this study was to determine the optimum organic loading rate for operating a modified UASB reactor to treat vinasse generated in the production of hydrous ethanol from sugar cane molasses. The study showed that chemical oxygen demand (COD) removal efficiency was 69% at an optimum organic loading rate (OLR) of 17.05 kg COD/m3-day, achieving a methane yield of 0.263 m3/kg CODadded and a biogas methane content of 84%. During this stage, effluent characterization presented lower values than the vinasse, except for potassium, sulfide and ammonia nitrogen. On the other hand, primers used to amplify the 16S-rDNA genes for the domains Archaea and Bacteria showed the presence of microorganisms which favor methane production at the optimum organic loading rate. The modified UASB reactor proposed in this study provided a successful treatment of the vinasse obtained from hydrous ethanol production.Methanogen groups (Methanobacteriales and Methanosarcinales) detected by PCR during operational optimum OLR of the modified UASB reactor, favored methane production.

Molecular interaction of (ethanol)2-water heterotrimers.

PubMed

Mejía, Sol M; Espinal, Juan F; Restrepo, Albeiro; Mondragón, Fanor

2007-08-23

The potential energy surface of the (ethanol)2-water heterotrimers for the trans and gauche conformers of ethanol was studied using density functional theory. The same approximation was used for characterizing representative clusters of (ethanol)3, (methanol)3, and (methanol)2-water. Trimerization energies and enthalpies as well as the analysis of geometric parameters suggest that the structures with a cyclic pattern in the three hydrogen bonds of the type O-H---O (primary hydrogen bonds), where all molecules are proton donor-acceptor at the same time, are more stable than those with just two primary hydrogen bonds. Additionally, we propose the formation of "secondary hydrogen bonds" between hydrogen atoms of the methyl group of ethanol and the oxygen atom of water or other ethanol molecule (C-H---O), which were found to be weaker than the primary hydrogen bonds.

Techno-economic analysis of extraction-based separation systems for acetone, butanol, and ethanol recovery and purification.

PubMed

Grisales Díaz, Víctor Hugo; Olivar Tost, Gerard

2017-01-01

Dual extraction, high-temperature extraction, mixture extraction, and oleyl alcohol extraction have been proposed in the literature for acetone, butanol, and ethanol (ABE) production. However, energy and economic evaluation under similar assumptions of extraction-based separation systems are necessary. Hence, the new process proposed in this work, direct steam distillation (DSD), for regeneration of high-boiling extractants was compared with several extraction-based separation systems. The evaluation was performed under similar assumptions through simulation in Aspen Plus V7.3 ® software. Two end distillation systems (number of non-ideal stages between 70 and 80) were studied. Heat integration and vacuum operation of some units were proposed reducing the energy requirements. Energy requirement of hybrid processes, substrate concentration of 200 g/l, was between 6.4 and 8.3 MJ-fuel/kg-ABE. The minimum energy requirements of extraction-based separation systems, feeding a water concentration in the substrate equivalent to extractant selectivity, and ideal assumptions were between 2.6 and 3.5 MJ-fuel/kg-ABE, respectively. The efficiencies of recovery systems for baseline case and ideal evaluation were 0.53-0.57 and 0.81-0.84, respectively. The main advantages of DSD were the operation of the regeneration column at atmospheric pressure, the utilization of low-pressure steam, and the low energy requirements of preheating. The in situ recovery processes, DSD, and mixture extraction with conventional regeneration were the approaches with the lowest energy requirements and total annualized costs.

A low-temperature ZnO nanowire ethanol gas sensor prepared on plastic substrate

NASA Astrophysics Data System (ADS)

Lin, Chih-Hung; Chang, Shoou-Jinn; Hsueh, Ting-Jen

2016-09-01

In this work, a low-temperature ZnO nanowire ethanol gas sensor was prepared on plastic substrate. The operating temperature of the ZnO nanowire ethanol gas sensor was reduced to room temperature using ultraviolet illumination. The experimental results indicate a favorable sensor response at low temperature, with the best response at 60 °C. The results also reveal that the ZnO nanowire ethanol gas sensor can be easily integrated into portable products, whose waste heat can improve sensor response and achieve energy savings, while energy consumption can be further reduced by solar irradiation.

Ethanol fixed brain imaging by phase-contrast X-ray technique

NASA Astrophysics Data System (ADS)

Takeda, Tohoru; Thet-Thet-Lwin; Kunii, Takuya; Sirai, Ryota; Ohizumi, Takahito; Maruyama, Hiroko; Hyodo, Kazuyuki; Yoneyama, Akio; Ueda, Kazuhiro

2013-03-01

The two-crystal phase-contrast X-ray imaging technique using an X-ray crystal interferometer can depict the fine structures of rat's brain such as cerebral cortex, white matter, and basal ganglia. Image quality and contrast by ethanol fixed brain showed significantly better than those by usually used formalin fixation at 35 keV X-ray energy. Image contrast of cortex by ethanol fixation was more than 3-times higher than that by formalin fixation. Thus, the technique of ethanol fixation might be better suited to image cerebral structural detail at 35 keV X-ray energy.

Fuel ethanol production from sweet sorghum using repeated-batch fermentation.

PubMed

Chohnan, Shigeru; Nakane, Megumi; Rahman, M Habibur; Nitta, Youji; Yoshiura, Takanori; Ohta, Hiroyuki; Kurusu, Yasurou

2011-04-01

Ethanol was efficiently produced from three varieties of sweet sorghum using repeated-batch fermentation without pasteurization or acidification. Saccharomyces cerevisiae cells could be recycled in 16 cycles of the fermentation process with good ethanol yields. This technique would make it possible to use a broader range of sweet sorghum varieties for ethanol production. Copyright © 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

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.

Simultaneous Saccharification and Fermentation of Sugar Beet Pulp for Efficient Bioethanol Production.

PubMed

Berłowska, Joanna; Pielech-Przybylska, Katarzyna; Balcerek, Maria; Dziekońska-Kubczak, Urszula; Patelski, Piotr; Dziugan, Piotr; Kręgiel, Dorota

2016-01-01

Sugar beet pulp, a byproduct of sugar beet processing, can be used as a feedstock in second-generation ethanol production. The objective of this study was to investigate the effects of pretreatment, of the dosage of cellulase and hemicellulase enzyme preparations used, and of aeration on the release of fermentable sugars and ethanol yield during simultaneous saccharification and fermentation (SSF) of sugar beet pulp-based worts. Pressure-thermal pretreatment was applied to sugar beet pulp suspended in 2% w/w sulphuric acid solution at a ratio providing 12% dry matter. Enzymatic hydrolysis was conducted using Viscozyme and Ultraflo Max (Novozymes) enzyme preparations (0.015-0.02 mL/g dry matter). Two yeast strains were used for fermentation: Ethanol Red ( S. cerevisiae ) (1 g/L) and Pichia stipitis (0.5 g/L), applied sequentially. The results show that efficient simultaneous saccharification and fermentation of sugar beet pulp was achieved. A 6 h interval for enzymatic activation between the application of enzyme preparations and inoculation with Ethanol Red further improved the fermentation performance, with the highest ethanol concentration reaching 26.9 ± 1.2 g/L and 86.5 ± 2.1% fermentation efficiency relative to the theoretical yield.

Methane biofiltration in the presence of ethanol vapor under steady and transient state conditions: an experimental study.

PubMed

Ferdowsi, Milad; Ramirez, Antonio Avalos; Jones, Joseph Peter; Heitz, Michèle

2017-09-01

Methane (CH 4 ) removal in the presence of ethanol vapors was performed by a stone-based bed and a hybrid packing biofilter in parallel. In the absence of ethanol, a methane removal efficiency of 55 ± 1% was obtained for both biofilters under similar CH 4 inlet load (IL) of 13 ± 0.5 g CH4  m -3  h -1 and an empty bed residence time (EBRT) of 6 min. The results proved the key role of the bottom section in both biofilters for simultaneous removal of CH 4 and ethanol. Ethanol vapor was completely eliminated in the bottom sections for an ethanol IL variation between 1 and 11 g ethanol  m -3  h -1 . Ethanol absorption and accumulation in the biofilm phase as well as ethanol conversion to CO 2 contributed to ethanol removal efficiency of 100%. In the presence of ethanol vapor, CO 2 productions in the bottom section increased almost fourfold in both biofilters. The ethanol concentration in the leachate of the biofilter exceeding 2200 g ethanol  m -3 leachate in both biofilters demonstrated the excess accumulation of ethanol in the biofilm phase. The biofilters responded quickly to an ethanol shock load followed by a starvation with 20% decrease of their performance. The return to normal operations in both biofilters after the transient conditions took less than 5 days. Unlike the hybrid packing biofilter, excess pressure drop (up to 1.9 cmH 2 O m -1 ) was an important concern for the stone bed biofilter. The biomass accumulation in the bottom section of the stone bed biofilter contributed to 80% of the total pressure drop. However, the 14-day starvation reduced the pressure drop to 0.25 cmH 2 O m -1 .

Ultrathin layered double hydroxide nanosheets with Ni(III) active species obtained by exfoliation for highly efficient ethanol electrooxidation

PubMed Central

Xu, Liang; Wang, Zhe; Chen, Xu; Qu, Zongkai; Li, Feng; Yang, Wensheng

2018-01-01

The development of non-precious metal electrocatalysts for renewable energy conversion and storage is compelling but greatly challenging due to low activity of the existing catalysts. Herein, the ultrathin NiAl-layered double hydroxide nanosheets (NiAl-LDH-NSs) are prepared by simple liquid-exfoliation of bulk NiAl-LDHs and first used as ethanol electrooxidation catalysts. The ultrathin two-dimensional (2D) structure ensures that the LDH nanosheets expose a greater number of active sites. More importantly, much Ni(III) active species (NiOOH) in the ultrathin nanosheets are formed by the exfoliation process, which play an authentic catalytic role in the ethanol oxidation reaction (EOR). The presence of NiOOH remarkably improves the reactivity and electrical conductivity of LDH nanosheets. These synergistic effects lead to strikingly more than 30 times enhanced EOR activity of NiAl-LDH-NSs compared to bulk NiAl-LDHs. The obtained electrocatalytic activity is also much better than those of most Ni- and LDH-based EOR catalysts reported to date. In addition, the ultrathin NiAl-LDH-NS electrocatalyst also exhibits good long-term stability (maintain 81.8% of the original value after 10000 s). This study not only provides a highly competitive EOR catalyst, but also opens new avenues toward the design of highly efficient electrode materials that have various potential applications in supercapacitor, Ni-MH battery and other electrocatalytic systems. PMID:29622818

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

Investigating the effect of various extracting solvents on the potential use of red-apple skin (Malus domestica) as natural sensitizer for dye-sensitized solar cell

NASA Astrophysics Data System (ADS)

Saputro, Aldhi; Mizan, Adlan; Sofyan, Nofrijon; Yuwono, Akhmad Herman

2017-03-01

In the current investigation, the natural dye extracted from red-apple (Malus domestica) skin was used as natural sensitizer for dye sensitized solar cell (DSSC) application. The present study was specifically aimed at observing the effect of different solvents, i.e. deionized water, ethanol, and acidified ethanol, on the performance of the natural dye and thus the DSSC. For synthesis purposes, red-apple skin was peeled off, dried, crushed and furthermore extracted with ratio red-apple skin powder to solvent 1:20 w/v for 2 hours at 50°C under mechanical stirring. Subsequently, the resulting natural dyes with different solvents were examined by Fourier transform infrared (FTIR) to analyze their functional groups, UV-Vis spectroscopy to observe their absorption spectra for a wide range of wavelength, while TiO2 nanoparticle used as the semiconductor oxide layer in the device was characterized by field emission scanning electron microscope (FESEM). The FTIR results showed that the red-apple skin has anthocyanin group which functions as the sensitizer agent for photon energy absorption from the sunlight. The UV-Vis spectroscopy results showed that ethanol solvent has higher absorption of sunlight wavelength as compared to those of deionized water and acidified ethanol solvents. The performance test of the fabricated DSSC showed the prototype made of the red apple skin dye extracted by ethanol solvent can provide the highest open circuit voltage (Voc) up to 324 mV and efficiency around 0.046%. On the basis of investigation, it has been found that ethanol was the best solvent to extract anthocyanin from the red-apple skin.

Techno-economics of integrating bioethanol production from spent sulfite liquor for reduction of greenhouse gas emissions from sulfite pulping mills.

PubMed

Petersen, Abdul M; Haigh, Kate; Görgens, Johann F

2014-01-01

Flow sheet options for integrating ethanol production from spent sulfite liquor (SSL) into the acid-based sulfite pulping process at the Sappi Saiccor mill (Umkomaas, South Africa) were investigated, including options for generation of thermal and electrical energy from onsite bio-wastes, such as bark. Processes were simulated with Aspen Plus® for mass- and energy-balances, followed by an estimation of the economic viability and environmental impacts. Various concentration levels of the total dissolved solids in magnesium oxide-based SSL, which currently fuels a recovery boiler, prior to fermentation was considered, together with return of the fermentation residues (distillation bottoms) to the recovery boiler after ethanol separation. The generation of renewable thermal and electrical energy from onsite bio-wastes were also included in the energy balance of the combined pulping-ethanol process, in order to partially replace coal consumption. The bio-energy supplementations included the combustion of bark for heat and electricity generation and the bio-digestion of the calcium oxide SSL to produce methane as additional energy source. Ethanol production from SSL at the highest substrate concentration was the most economically feasible when coal was used for process energy. However this solution did not provide any savings in greenhouse gas (GHG) emissions for the concentration-fermentation-distillation process. Maximizing the use of renewable energy sources to partially replace coal consumption yielded a satisfactory economic performance, with a minimum ethanol selling price of 0.83 US$/l , and a drastic reduction in the overall greenhouse gas emissions for the entire facility. High substrate concentrations and conventional distillation should be used when considering integrating ethanol production at sulfite pulping mills. Bio-wastes generated onsite should be utilized at their maximum potential for energy generation in order to maximize the GHG emissions reduction.

A modified indirect mathematical model for evaluation of ethanol production efficiency in industrial-scale continuous fermentation processes.

PubMed

Canseco Grellet, M A; Castagnaro, A; Dantur, K I; De Boeck, G; Ahmed, P M; Cárdenas, G J; Welin, B; Ruiz, R M

2016-10-01

To calculate fermentation efficiency in a continuous ethanol production process, we aimed to develop a robust mathematical method based on the analysis of metabolic by-product formation. This method is in contrast to the traditional way of calculating ethanol fermentation efficiency, where the ratio between the ethanol produced and the sugar consumed is expressed as a percentage of the theoretical conversion yield. Comparison between the two methods, at industrial scale and in sensitivity studies, showed that the indirect method was more robust and gave slightly higher fermentation efficiency values, although fermentation efficiency of the industrial process was found to be low (~75%). The traditional calculation method is simpler than the indirect method as it only requires a few chemical determinations in samples collected. However, a minor error in any measured parameter will have an important impact on the calculated efficiency. In contrast, the indirect method of calculation requires a greater number of determinations but is much more robust since an error in any parameter will only have a minor effect on the fermentation efficiency value. The application of the indirect calculation methodology in order to evaluate the real situation of the process and to reach an optimum fermentation yield for an industrial-scale ethanol production is recommended. Once a high fermentation yield has been reached the traditional method should be used to maintain the control of the process. Upon detection of lower yields in an optimized process the indirect method should be employed as it permits a more accurate diagnosis of causes of yield losses in order to correct the problem rapidly. The low fermentation efficiency obtained in this study shows an urgent need for industrial process optimization where the indirect calculation methodology will be an important tool to determine process losses. © 2016 The Society for Applied Microbiology.

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.

Bioethanol Potential of Energy Sorghum Grown on Marginal and Arable Lands

PubMed Central

Tang, Chaochen; Li, Songbo; Li, Meng; Xie, Guang H.

2018-01-01

Field experiments were conducted in marginal lands, i.e., sub-humid climate and saline-land (SHS) and semi-arid climate and wasteland (SAW), to evaluate ethanol potential based on the biomass yield and chemical composition of biomass type (var. GN-2, GN-4, and GN-10) and sweet type (var. GT-3 and GT-7) hybrids of energy sorghum [Sorghum bicolor (L.) Moench] in comparison with sub-humid climate and cropland (SHC) in northern China. Results showed that environment significantly (p < 0.05) influenced plant growth, biomass yield and components, and subsequently the ethanol potential of energy sorghum. Biomass and theoretical ethanol yield of the crop grown at SHS (12.2 t ha−1 and 3,425 L ha−1, respectively) and SAW (8.6 t ha−1 and 2,091 L ha−1, respectively) were both statistically (p < 0.001) lower than values at the SHC site (32.6 t ha−1 and 11,853 L ha−1, respectively). Higher desirable contents of soluble sugar, cellulose, and hemicellulose were observed at SHS and SHC sites, while sorghum grown at SAW possessed higher lignin and ash contents. Biomass type sorghum was superior to sweet type as non-food ethanol feedstock. In particular, biomass type hybrid GN-10 achieved the highest biomass (17.4 t ha−1) and theoretical ethanol yields (5,423 L ha−1) after averaging data for all environmental sites. The most productive hybrid, biomass type GN-4, exhibited biomass and theoretical ethanol yields >42.1 t ha−1 and 14,913 L ha−1, respectively, at the cropland SHC site. In conclusion, energy sorghum grown on marginal lands showed a very lower ethanol potential, indicating a considerable lower possibility for being used as commercial feedstock supply when compared with that grown on regular croplands. Moreover, screening suitable varieties may improve energy sorghum growth and chemical properties for ethanol production on marginal lands. PMID:29686688

Availability of lignocellulose from forestry waste for use as a biofuel in China.

PubMed

Xie, Hui; Zhang, Dong; Mao, Guotao; Wang, Fengqin; Song, Andong

2018-05-01

Biomass is a very important renewable energy and plays an important role in the energy structure of China. Here, the role of forestry waste in producing energy in China was analyzed and the availability of forestry waste for biofuel production, theoretically collectable amounts of forest biomass, and density of forestry waste were assessed. Agricultural and forestry waste are important biomass resources. The potential for using forestry waste as a low cost substrate for producing fuel ethanol using existing forestry resources and techniques was analyzed, and the feasibility of producing fuel ethanol in different Chinese provinces was assessed using the specific situation for each province. The results showed that 1081.73 × 10 6  t of forestry waste could be produced in China, and 270.43 × 10 6  t (25% of the amount that could be collected) could be used to produce fuel ethanol. Assuming 10 t of sawdust could be converted into 1 t of ethanol, 27 × 10 6  t of ethanol could be produced from forestry waste. Different provinces have different potentials for producing ethanol from forestry waste, Guangdong Province, Guangxi Province, Sichuan Province, and Yunnan Province having higher potentials than the other provinces. It was predicted that 4478 × 10 6  t of fuel ethanol could be produced from woodcraft waste by 2020, and the provinces with the most potential were found to be Fujian Province, Heilongjiang Province, Jilin Province, Shanxi Province, Sichuan Province, Xinjiang Province, and Yunnan Province. Using forestry waste to produce ethanol could alleviate the energy shortage in China.

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

Optimization study of ethanolic fermentation from oil palm trunk, rubberwood and mixed hardwood hydrolysates using Saccharomyces cerevisiae.

PubMed

Chin, K L; H'ng, P S; Wong, L J; Tey, B T; Paridah, M T

2010-05-01

Ethanolic fermentation using Saccharomyces cerevisiae was carried out on three types of hydrolysates produced from lignocelulosic biomass which are commonly found in Malaysia such as oil palm trunk, rubberwood and mixed hardwood. The effect of fermentation temperature and pH of hydrolysate was evaluated to optimize the fermentation efficiency which defined as maximum ethanol yield in minimum fermentation time. The fermentation process using different temperature of 25 degrees Celsius, 30 degrees Celsius and 40 degrees Celsius were performed on the prepared fermentation medium adjusted to pH 4, pH 6 and pH 7, respectively. Results showed that the fermentation time was significantly reduced with the increase of temperature but an adverse reduction in ethanol yield was observed using temperature of 40 degrees Celsius. As the pH of hydrolysate became more acidic, the ethanol yield increased. Optimum fermentation efficiency for ethanolic fermentation of lignocellulosic hydrolysates using S. cerevisiae can be obtained using 33.2 degrees Celsius and pH 5.3. Copyright 2009 Elsevier Ltd. All rights reserved.

Ethanol production from lignocellulosic hydrolysates using engineered Saccharomyces cerevisiae harboring xylose isomerase-based pathway.

PubMed

Ko, Ja Kyong; Um, Youngsoon; Woo, Han Min; Kim, Kyoung Heon; Lee, Sun-Mi

2016-06-01

The efficient co-fermentation of glucose and xylose is necessary for the economically feasible bioethanol production from lignocellulosic biomass. Even with xylose utilizing Saccharomyces cerevisiae, the efficiency of the lignocellulosic ethanol production remains suboptimal mainly due to the low conversion yield of xylose to ethanol. In this study, we evaluated the co-fermentation performances of SXA-R2P-E, a recently engineered isomerase-based xylose utilizing strain, in mixed sugars and in lignocellulosic hydrolysates. In a high-sugar fermentation with 70g/L of glucose and 40g/L of xylose, SXA-R2P-E produced 50g/L of ethanol with an yield of 0.43gethanol/gsugars at 72h. From dilute acid-pretreated hydrolysates of rice straw and hardwood (oak), the strain produced 18-21g/L of ethanol with among the highest yield of 0.43-0.46gethanol/gsugars ever reported. This study shows a highly promising potential of a xylose isomerase-expressing strain as an industrially relevant ethanol producer from lignocellulosic hydrolysates. Copyright © 2016 Elsevier Ltd. All rights reserved.

Natural and anthropogenic ethanol sources inNorth America and potential atmospheric impacts of ethanol fuel use.

PubMed

Millet, Dylan B; Apel, Eric; Henze, Daven K; Hill, Jason; Marshall, Julian D; Singh, Hanwant B; Tessum, Christopher W

2012-08-07

We used an ensemble of aircraft measurements with the GEOS-Chem chemical transport model to constrain present-day North American ethanol sources, and gauge potential long-range impacts of increased ethanol fuel use. We find that current ethanol emissions are underestimated by 50% in Western North America, and overestimated by a factor of 2 in the east. Our best estimate for year-2005 North American ethanol emissions is 670 GgC/y, with 440 GgC/y from the continental U.S. We apply these optimized source estimates to investigate two scenarios for increased ethanol fuel use in the U.S.: one that assumes a complete transition from gasoline to E85 fuel, and one tied to the biofuel requirements of the U.S. Energy Indepence and Security Act (EISA). For both scenarios, increased ethanol emissions lead to higher atmospheric acetaldehyde concentrations (by up to 14% during winter for the All-E85 scenario and 2% for the EISA scenario) and an associated shift in reactive nitrogen partitioning reflected by an increase in the peroxyacetyl nitrate (PAN) to NO(y) ratio. The largest relative impacts occur during fall, winter, and spring because of large natural emissions of ethanol and other organic compounds during summer. Projected changes in atmospheric PAN reflect a balance between an increased supply of peroxyacetyl radicals from acetaldehyde oxidation, and the lower NO(x) emissions for E85 relative to gasoline vehicles. The net effect is a general PAN increase in fall through spring, and a weak decrease over the U.S. Southeast and the Atlantic Ocean during summer. Predicted NO(x) concentrations decrease in surface air over North America (by as much 5% in the All-E85 scenario). Downwind of North America this effect is counteracted by higher NO(x) export efficiency driven by increased PAN production and transport. From the point of view of NO(x) export from North America, the increased PAN formation associated with E85 fuel use thus acts to offset the associated lower NO(x) emissions.

Anharmonicity and confinement in zeolites: Structure, spectroscopy, and adsorption free energy of ethanol in H-ZSM-5

DOE PAGES

Alexopoulos, Konstantinos; Lee, Mal -Soon; Liu, Yue; ...

2016-03-21

Here, to account for thermal and entropic effects caused by the dynamics of the motion of the reaction intermediates, ethanol adsorption on the Brønsted acid site of the H-ZSM-5 catalyst has been studied at different temperatures and ethanol loadings using ab initio molecular dynamics (AIMD) simulations, infrared (IR) spectroscopy and calorimetric measurements. At low temperatures (T ≤ 400 K) and ethanol loading, a single ethanol molecule adsorbed in H-ZSM-5 forms a Zundel-like structure where the proton is equally shared between the oxygen of the zeolite and the oxygen of the alcohol. At higher ethanol loading, a second ethanol molecule helpsmore » to stabilize the protonated ethanol at all temperatures by acting as a solvating agent. The vibrational density of states (VDOS), as calculated from the AIMD simulations, are in excellent agreement with measured IR spectra for C 2H 5OH, C 2H 5OD and C 2D 5OH isotopomers and support the existence of both monomers and dimers. A quasi-harmonic approximation (QHA), applied to the VDOS obtained from the AIMD simulations, provides estimates of adsorption free energy within ~10 kJ/mol of the experimentally determined quantities, whereas the traditional approach, employing harmonic frequencies from a single ground state minimum, strongly overestimates the adsorption free energy by at least ~30 kJ/mol. This discrepancy is traced back to the inability of the harmonic approximation to represent the contributions to the vibrational motions of the ethanol molecule upon confinement in the zeolite. KA, MFR, GBM were supported by the Long Term Structural Methusalem Funding by the Flemish Government – grant number BOF09/01M00409. MSL, VAG, RR and JAL were supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. PNNL is a multiprogram national laboratory operated for DOE by Battelle. Computational resources were provided at W. R. Wiley Environmental Molecular Science Laboratory (EMSL), a national scientific user facility sponsored by the Department of Energy’s Office of Biological and Environmental Research located at PNNL, the National Energy Research Scientific Computing Center (NERSC) at Lawrence Berkeley National Laboratory and the Stevin Supercomputer Infrastructure at Ghent University.« less

Assessments of low emission asphalt mixtures produced using combinations of foaming agents

NASA Astrophysics Data System (ADS)

Mohd Hasan, Mohd Rosli

The asphalt foaming techniques have been used over the last couple of decades as an alternative to the traditional method of preparing asphalt mixtures. Based on positive feedback from the industry, this study was initiated to explore and evaluate the performance of the Warm Mix Asphalt (WMA) mixture produced through a foaming process using physical and chemical foaming agents, which are ethanol and sodium bicarbonate (NaHCO3), respectively. The success of this project may lead to new theories and provide an environmentally friendly technique to produce asphalt mixtures. This may advance the understanding of the foaming process and improve the performance of WMA to support sustainable development. Theoretically, ethanol can function in the same manner as water but requires less energy to foam due to its lower boiling point, 78°C. During the asphalt foaming process, numerous bubbles were generated by the vaporized ethanol, which significantly increased the volume of the asphalt binder, hence the coating potential of aggregates improves. The sodium bicarbonate was incorporated to enhance the quantity of bubbles and its stability. Therefore, understanding foaming agents, their solubility, chemical reactions, chemical function groups and rheological properties of the foamed binder are essential to help control the foam structure and final properties of the foamed WMA mixture. In order to understand the overall performance of newly developed foaming WMA, this material was evaluated for moisture susceptibility, rutting potential, and resistance to fracture and thermal cracking. The coatability, workability and compactability of foamed asphalt mixtures during production were also evaluated. Based on the results, it was found that the newly proposed foaming WMA has high potential to promote sustainable development by lowering the energy consumption and impacts on the environment. The ethanol is efficient in lowering the viscosity of asphalt binders, enhancing the workability, and having a higher expulsion rate from the foamed binder compared to water as a foaming agent. The addition of foaming agents to the asphalt binder has also lowered the activation energy of the asphalt binder, which has high potential in lowering the energy demand during production processes. The foamed WMA mixture prepared at 100°C was found to have behavior comparable with the control Hot Mix Asphalt (HMA) prepared at 155°C in terms of coatability, workability and compactability. Based on the mixture performance tests, the foamed WMA has a comparable or better performance than the HMA in terms of resistance to moisture damage, permanent deformation, fracture cracking and thermal cracking. The application of nano-hydrated lime is efficient in enhancing the aggregate coatability and improving the bearing capacity of asphalt pavement to lower the rutting potential and moisture susceptibility of foamed WMA mixtures. Limitations for each of the related parameters are also reported in this dissertation for the lab production of foamed WMA mixtures using ethanol and NaHCO 3 as foaming agents. The specified values were made based on the binder test, service characteristics and performance of foamed WMA mixtures in order to yield a comparable or better performance than the control HMA. Field validations should be carried out to understand the overall performance and durability of the proposed foaming WMA.

Band-like transport in highly crystalline graphene films from defective graphene oxides.

PubMed

Negishi, R; Akabori, M; Ito, T; Watanabe, Y; Kobayashi, Y

2016-07-01

The electrical transport property of the reduced graphene oxide (rGO) thin-films synthesized from defective GO through thermal treatment in a reactive ethanol environment at high temperature above 1000 °C shows a band-like transport with small thermal activation energy (Ea~10 meV) that occurs during high carrier mobility (~210 cm(2)/Vs). Electrical and structural analysis using X-ray absorption fine structure, the valence band photo-electron, Raman spectra and transmission electron microscopy indicate that a high temperature process above 1000 °C in the ethanol environment leads to an extraordinary expansion of the conjugated π-electron system in rGO due to the efficient restoration of the graphitic structure. We reveal that Ea decreases with the increasing density of states near the Fermi level due to the expansion of the conjugated π-electron system in the rGO. This means that Ea corresponds to the energy gap between the top of the valence band and the bottom of the conduction band. The origin of the band-like transport can be explained by the carriers, which are more easily excited into the conduction band due to the decreasing energy gap with the expansion of the conjugated π-electron system in the rGO.

Band-like transport in highly crystalline graphene films from defective graphene oxides

NASA Astrophysics Data System (ADS)

Negishi, R.; Akabori, M.; Ito, T.; Watanabe, Y.; Kobayashi, Y.

2016-07-01

The electrical transport property of the reduced graphene oxide (rGO) thin-films synthesized from defective GO through thermal treatment in a reactive ethanol environment at high temperature above 1000 °C shows a band-like transport with small thermal activation energy (Ea~10 meV) that occurs during high carrier mobility (~210 cm2/Vs). Electrical and structural analysis using X-ray absorption fine structure, the valence band photo-electron, Raman spectra and transmission electron microscopy indicate that a high temperature process above 1000 °C in the ethanol environment leads to an extraordinary expansion of the conjugated π-electron system in rGO due to the efficient restoration of the graphitic structure. We reveal that Ea decreases with the increasing density of states near the Fermi level due to the expansion of the conjugated π-electron system in the rGO. This means that Ea corresponds to the energy gap between the top of the valence band and the bottom of the conduction band. The origin of the band-like transport can be explained by the carriers, which are more easily excited into the conduction band due to the decreasing energy gap with the expansion of the conjugated π-electron system in the rGO.

Metal-Organic Frameworks in Adsorption-Driven Heat Pumps: The Potential of Alcohols as Working Fluids.

PubMed

de Lange, Martijn F; van Velzen, Benjamin L; Ottevanger, Coen P; Verouden, Karlijn J F M; Lin, Li-Chiang; Vlugt, Thijs J H; Gascon, Jorge; Kapteijn, Freek

2015-11-24

A large fraction of global energy is consumed for heating and cooling. Adsorption-driven heat pumps and chillers could be employed to reduce this consumption. MOFs are often considered to be ideal adsorbents for heat pumps and chillers. While most published works to date on this topic have focused on the use of water as a working fluid, the instability of many MOFs to water and the fact that water cannot be used at subzero temperatures pose certain drawbacks. The potential of using alcohol-MOF pairs in adsorption-driven heat pumps and chillers is investigated. To this end, 18 different selected MOF structures in combination with either methanol or ethanol as a working fluid are considered, and their potential is assessed on the basis of adsorption measurements and thermodynamic efficiencies. If alcohols are used instead of water, then (1) adsorption occurs at lower relative pressures for methanol and even lower pressure for ethanol, (2) larger pores can be utilized efficiently, as hysteresis is absent for pores smaller than 3.4 nm (2 nm for water), (3) larger pore sizes need to be employed to ensure the desired stepwise adsorption, (4) the effect of (polar/apolar) functional groups in the MOF is far less pronounced, (5) the energy released or taken up per cycle is lower, but heat and mass transfer may be enhanced, (6) stability of MOFs seems to be less of an issue, and (7) cryogenic applications (e.g., ice making) become feasible. From a thermodynamic perspective, UiO-67, CAU-3, and ZIF-8 seem to be the most promising MOFs for both methanol and ethanol as working fluids. Although UiO-67 might not be completely stable, both CAU-3 and ZIF-8 have the potential to be applied, especially in subzero-temperature adsorption chillers (AC).

Mechanistic studies on the transformation of ethanol into ethene over Fe-ZSM-5 zeolite.

PubMed

Maihom, Thana; Khongpracha, Pipat; Sirijaraensre, Jakkapan; Limtrakul, Jumras

2013-01-14

Ethanol, through the utilization of bioethanol as a chemical resource, has received considerable industrial attention as it provides an alternative route to produce more valuable hydrocarbons. Using a density functional theory approach incorporating the M06-L functional, which includes dispersion interactions, a large 34T nanocluster model of Fe-ZSM-5 zeolite in which T is a Si or Al atom is employed to examine both the stepwise and concerted mechanisms of the transformation of ethanol into ethene. For the stepwise mechanism, ethanol dehydration commences from the first hydrogen abstraction of the ethanol OH group to form the ethoxide-hydroxide intermediate with a low activation energy of 17.7 kcal mol(-1). Consequently, the ethoxide-hydroxide intermediate is decomposed into ethene through hydrogen abstraction from the ethoxide methyl carbon to either the OH group of hydroxide or the oxygen of the ethoxide group with high activation energies of 64.8 and 63.5 kcal mol(-1), respectively. For the concerted mechanism, ethanol transformation into the ethene product occurs in a single step without intermediate formation, with an activation energy of 32.9 kcal mol(-1). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ethanol generation, oxidation and energy production in a cooperative bioelectrochemical system.

PubMed

Pagnoncelli, Kamila C; Pereira, Andressa R; Sedenho, Graziela C; Bertaglia, Thiago; Crespilho, Frank N

2018-08-01

Integrating in situ biofuel production and energy conversion into a single system ensures the production of more robust networks as well as more renewable technologies. For this purpose, identifying and developing new biocatalysts is crucial. Herein, is reported a bioelectrochemical system consisting of alcohol dehydrogenase (ADH) and Saccharomyces cerevisiae, wherein both function cooperatively for ethanol production and its bioelectrochemical oxidation. Here, it is shown that it is possible to produce ethanol and use it as a biofuel in a tandem manner. The strategy is to employ flexible carbon fibres (FCF) electrode that could adsorb both the enzyme and the yeast cells. Glucose is used as a substrate for the yeast for the production of ethanol, while the enzyme is used to catalyse the oxidation of ethanol to acetaldehyde. Regarding the generation of reliable electricity based on electrochemical systems, the biosystem proposed in this study operates at a low temperature and ethanol production is proportional to the generated current. With further optimisation of electrode design, we envision the use of the cooperative biofuel cell for energy conversion and management of organic compounds. Copyright © 2018 Elsevier B.V. All rights reserved.

Metabolic Engineering of Microorganisms for the Production of Higher Alcohols

PubMed Central

Choi, Yong Jun; Lee, Joungmin; Jang, Yu-Sin

2014-01-01

ABSTRACT Due to the increasing concerns about limited fossil resources and environmental problems, there has been much interest in developing biofuels from renewable biomass. Ethanol is currently used as a major biofuel, as it can be easily produced by existing fermentation technology, but it is not the best biofuel due to its low energy density, high vapor pressure, hygroscopy, and incompatibility with current infrastructure. Higher alcohols, including 1-propanol, 1-butanol, isobutanol, 2-methyl-1-butanol, and 3-methyl-1-butanol, which possess fuel properties more similar to those of petroleum-based fuel, have attracted particular interest as alternatives to ethanol. Since microorganisms isolated from nature do not allow production of these alcohols at high enough efficiencies, metabolic engineering has been employed to enhance their production. Here, we review recent advances in metabolic engineering of microorganisms for the production of higher alcohols. PMID:25182323

Metabolic engineering of microorganisms for the production of higher alcohols.

PubMed

Choi, Yong Jun; Lee, Joungmin; Jang, Yu-Sin; Lee, Sang Yup

2014-09-02

Due to the increasing concerns about limited fossil resources and environmental problems, there has been much interest in developing biofuels from renewable biomass. Ethanol is currently used as a major biofuel, as it can be easily produced by existing fermentation technology, but it is not the best biofuel due to its low energy density, high vapor pressure, hygroscopy, and incompatibility with current infrastructure. Higher alcohols, including 1-propanol, 1-butanol, isobutanol, 2-methyl-1-butanol, and 3-methyl-1-butanol, which possess fuel properties more similar to those of petroleum-based fuel, have attracted particular interest as alternatives to ethanol. Since microorganisms isolated from nature do not allow production of these alcohols at high enough efficiencies, metabolic engineering has been employed to enhance their production. Here, we review recent advances in metabolic engineering of microorganisms for the production of higher alcohols. Copyright © 2014 Choi et al.

Production of pyrite nanoparticles using high energy planetary ball milling for sonocatalytic degradation of sulfasalazine.

PubMed

Khataee, Alireza; Fathinia, Siavash; Fathinia, Mehrangiz

2017-01-01

Sonocatalytic performance of pyrite nanoparticles was evaluated by the degradation of sulfasalazine (SSZ). Pyrite nanoparticles were produced via a high energy mechanical ball milling (MBM) in different processing time from 2h to 6h, in the constant milling speed of 320rpm. X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FT-IR) analysis and Brunauer-Emmett-Teller (BET) confirmed the production of pyrite nanoparticles during 6h of ball milling with the average size distribution of 20-80nm. The effects of various operational parameters including pH value, catalyst amount (mg/L), SSZ concentration (mg/L), ultrasonic frequency (kHz) and reaction time on the SSZ removal efficiency were examined. The obtained results showed that the maximum removal efficiency of 97.00% was obtained at pH value of 4, catalyst dosage of 0.5g/L, SSZ concentration of 10mg/L and reaction time of 30min. Experimental results demonstrated that the kinetic of the degradation process can be demonstrated using Langmuir-Hinshelwood (L-H) kinetic model. The effect of different inorganic ions such as Cl - , CO 3 2- and SO 4 2- was investigated on the L-H reaction rate (k r ) and adsorption (K s ) constants. Results showed that the presence of the mentioned ions significantly influenced the L-H constants. The impact of ethanol as a OH radical scavenger and some enhancers including H 2 O 2 and K 2 S 2 O 8 was investigated on the SSZ removal efficiency. Accordingly, the presence of ethanol suppressed SSZ degradation due to the quenching of OH radicals and the addition of K 2 S 2 O 8 and H 2 O 2 increased the SSZ removal efficiency, due to the formation of SO 4 - and additional OH radicals, respectively. Under the identical conditions of operating parameters, pyrite nanoparticles maintained their catalytic activity during four consecutive runs. Copyright © 2016 Elsevier B.V. All rights reserved.

[Influencing factors in preparation of brucine liposomes by ammonium sulfate transmembrane gradients].

PubMed

Wang, Wei; Chen, Jun; Cai, Bao-Chang; Fang, Yun

2008-09-01

To study the influencing factors in preparation of brucine liposomes by ammonium sulfate transmembrane gradients. The brucine liposomes were separated by Sephadex G-50, and the influence of various factors on the entrapment efficiencies were investigated. The entrapment efficiency was enhanced by increased ammonium sulfate concentration, ethanol volume and PC concentration. Burcine liposomes prepared by ammonium sulfate transmembrance gradients can get a high entrapment efficiency, the main influencing factors were ammonium sulfate concentration, ethanol volume and PC concentration.

Analysis of Thermal and Chemical Effets on Negative Valve Overlap Period Energy Recovery for Low-Temperature Gasoline Combustion

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

Ekoto, Dr Isaac; Peterson, Dr. Brian; Szybist, James P

2015-01-01

A central challenge for efficient auto-ignition controlled low-temperature gasoline combustion (LTGC) engines has been achieving the combustion phasing needed to reach stable performance over a wide operating regime. The negative valve overlap (NVO) strategy has been explored as a way to improve combustion stability through a combination of charge heating and altered reactivity via a recompression stroke with a pilot fuel injection. The study objective was to analyze the thermal and chemical effects on NVO-period energy recovery. The analysis leveraged experimental gas sampling results obtained from a single-cylinder LTGC engine along with cylinder pressure measurements and custom data reduction methodsmore » used to estimate period thermodynamic properties. The engine was fueled by either iso-octane or ethanol, and operated under sweeps of NVO-period oxygen concentration, injection timing, and fueling rate. Gas sampling at the end of the NVO period was performed via a custom dump-valve apparatus, with detailed sample speciation by in-house gas chromatography. The balance of NVO-period input and output energy flows was calculated in terms of fuel energy, work, heat loss, and change in sensible energy. Experiment results were complemented by detailed chemistry single-zone reactor simulations performed at relevant mixing and thermodynamic conditions, with results used to evaluate ignition behavior and expected energy recovery yields. For the intermediate bulk-gas temperatures present during the NVO period (900-1100 K), weak negative temperature coefficient behavior with iso-octane fueling significantly lengthened ignition delays relative to similar ethanol fueled conditions. Faster ethanol ignition chemistry led to lower recovered fuel intermediate yields relative to similar iso-octane fueled conditions due to more complete fuel oxidation. From the energy analysis it was found that increased NVO-period global equivalence ratio, either from lower NVOperiod oxygen concentrations or higher fueling rates, in general led to a greater fraction of net recovered fuel energy and work as heat losses were minimized. These observations were supported by complementary single-zone reactor model results, which further indicated that kinetic time-scales favor chemical energy-consuming exothermic oxidation over slower endothermic reformation. Nonetheless, fuel energy recovery close to the thermodynamic equilibrium solution was achieved for baseline conditions that featured 4% NVO-period oxygen concentration.« less

Efficient bioconversion of rice straw to ethanol with TiO2/UV pretreatment.

PubMed

Kang, Hee-Kyoung; Kim, Doman

2012-01-01

Rice straw is a lignocellulosic biomass that constitutes a renewable organic substance and alternative source of energy; however, its structure confounds the liberation of monosaccharides. Pretreating rice straw using a TiO(2)/UV system facilitated its hydrolysis with Accellerase 1000(™), suggesting that hydroxyl radicals (OH·) from the TiO(2)/UV system could degrade lignin and carbohydrates. TiO(2)/UV pretreatment was an essential step for conversion of hemicellulose to xylose; optimal conditions for this conversion were a TiO(2) concentration of 0.1% (w/v) and an irradiation time of 2 h with a UV-C lamp at 254 nm. After enzymatic hydrolysis, the sugar yields from rice straw pretreated with these parameters were 59.8 ± 0.7% of the theoretical for glucose (339 ± 13 mg/g rice straw) and 50.3 ± 2.8% for xylose (64 ± 3 mg/g rice straw). The fermentation of enzymatic hydrolysates containing 10.5 g glucose/L and 3.2 g xylose/L with Pichia stipitis produced 3.9 g ethanol/L with a corresponding yield of 0.39 g/g rice straw. The maximum possible ethanol conversion rate is 76.47%. TiO(2)/UV pretreatment can be performed at room temperature and atmospheric pressure and demonstrates potential in large-scale production of fermentable sugars.

Santa Clara County Planar Solid Oxide Fuel Cell Demonstration Project

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

Fred Mitlitsky; Sara Mulhauser; David Chien

2009-11-14

The Santa Clara County Planar Solid Oxide Fuel Cell (PSOFC) project demonstrated the technical viability of pre-commercial PSOFC technology at the County 911 Communications headquarters, as well as the input fuel flexibility of the PSOFC. PSOFC operation was demonstrated on natural gas and denatured ethanol. The Santa Clara County Planar Solid Oxide Fuel Cell (PSOFC) project goals were to acquire, site, and demonstrate the technical viability of a pre-commercial PSOFC technology at the County 911 Communications headquarters. Additional goals included educating local permit approval authorities, and other governmental entities about PSOFC technology, existing fuel cell standards and specific code requirements.more » The project demonstrated the Bloom Energy (BE) PSOFC technology in grid parallel mode, delivering a minimum 15 kW over 8760 operational hours. The PSOFC system demonstrated greater than 81% electricity availability and 41% electrical efficiency (LHV net AC), providing reliable, stable power to a critical, sensitive 911 communications system that serves geographical boundaries of the entire Santa Clara County. The project also demonstrated input fuel flexibility. BE developed and demonstrated the capability to run its prototype PSOFC system on ethanol. BE designed the hardware necessary to deliver ethanol into its existing PSOFC system. Operational parameters were determined for running the system on ethanol, natural gas (NG), and a combination of both. Required modeling was performed to determine viable operational regimes and regimes where coking could occur.« less

Bioconversion of Agave tequilana fructans by exo-inulinases from indigenous Aspergillus niger CH-A-2010 enhances ethanol production from raw Agave tequilana juice.

PubMed

Huitrón, Carlos; Pérez, Rosalba; Gutiérrez, Luís; Lappe, Patricia; Petrosyan, Pavel; Villegas, Jesús; Aguilar, Cecilia; Rocha-Zavaleta, Leticia; Blancas, Abel

2013-01-01

Agave tequilana fructans are the source of fermentable sugars for the production of tequila. Fructans are processed by acid hydrolysis or by cooking in ovens at high temperature. Enzymatic hydrolysis is considered an alternative for the bioconversion of fructans. We previously described the isolation of Aspergillus niger CH-A-2010, an indigenous strain that produces extracellular inulinases. Here we evaluated the potential application of A. niger CH-A-2010 inulinases for the bioconversion of A. tequilana fructans, and its impact on the production of ethanol. Inulinases were analyzed by Western blotting and thin layer chromatography. Optimal pH and temperature conditions for inulinase activity were determined. The efficiency of A. niger CH-A-2010 inulinases was compared with commercial enzymes and with acid hydrolysis. The hydrolysates obtained were subsequently fermented by Saccharomyces cerevisiae to determine the efficiency of ethanol production. Results indicate that A. niger CH-A-2010 predominantly produces an exo-inulinase activity. Optimal inulinase activity occurred at pH 5.0 and 50 °C. Hydrolysis of raw agave juice by CH-A-2010 inulinases yielded 33.5 g/l reducing sugars, compared with 27.3 g/l by Fructozyme(®) (Novozymes Corp, Bagsværd, Denmark) and 29.4 g/l by acid hydrolysis. After fermentation of hydrolysates, we observed that the conversion efficiency of sugars into ethanol was 97.5 % of the theoretical ethanol yield for enzymatically degraded agave juice, compared to 83.8 % for acid-hydrolyzed juice. These observations indicate that fructans from raw Agave tequilana juice can be efficiently hydrolyzed by using A. niger CH-A-2010 inulinases, and that this procedure impacts positively on the production of ethanol.

A novel solid state fermentation coupled with gas stripping enhancing the sweet sorghum stalk conversion performance for bioethanol

PubMed Central

2014-01-01

Background Bioethanol production from biomass is becoming a hot topic internationally. Traditional static solid state fermentation (TS-SSF) for bioethanol production is similar to the traditional method of intermittent operation. The main problems of its large-scale intensive production are the low efficiency of mass and heat transfer and the high ethanol inhibition effect. In order to achieve continuous production and high conversion efficiency, gas stripping solid state fermentation (GS-SSF) for bioethanol production from sweet sorghum stalk (SSS) was systematically investigated in the present study. Results TS-SSF and GS-SSF were conducted and evaluated based on different SSS particle thicknesses under identical conditions. The ethanol yield reached 22.7 g/100 g dry SSS during GS-SSF, which was obviously higher than that during TS-SSF. The optimal initial gas stripping time, gas stripping temperature, fermentation time, and particle thickness of GS-SSF were 10 h, 35°C, 28 h, and 0.15 cm, respectively, and the corresponding ethanol stripping efficiency was 77.5%. The ethanol yield apparently increased by 30% with the particle thickness decreasing from 0.4 cm to 0.05 cm during GS-SSF. Meanwhile, the ethanol yield increased by 6% to 10% during GS-SSF compared with that during TS-SSF under the same particle thickness. The results revealed that gas stripping removed the ethanol inhibition effect and improved the mass and heat transfer efficiency, and hence strongly enhanced the solid state fermentation (SSF) performance of SSS. GS-SSF also eliminated the need for separate reactors and further simplified the bioethanol production process from SSS. As a result, a continuous conversion process of SSS and online separation of bioethanol were achieved by GS-SSF. Conclusions SSF coupled with gas stripping meet the requirements of high yield and efficient industrial bioethanol production. It should be a novel bioconversion process for bioethanol production from SSS biomass. PMID:24713041

Engineering cyanobacteria for fuels and chemicals production.

PubMed

Zhou, Jie; Li, Yin

2010-03-01

The world's energy and global warming crises call for sustainable, renewable, carbon-neutral alternatives to replace fossil fuel resources. Currently, most biofuels are produced from agricultural crops and residues, which lead to concerns about food security and land shortage. Compared to the current biofuel production system, cyanobacteria, as autotrophic prokaryotes, do not require arable land and can grow to high densities by efficiently using solar energy, CO(2), water, and inorganic nutrients. Moreover, powerful genetic techniques of cyanobacteria have been developed. For these reasons, cyanobacteria, which carry out oxygenic photosynthesis, are attractive hosts for production of fuels and chemicals. Recently, several chemicals including ethanol, isobutanol and isoprene have been produced by engineered cyanobacteria directly using solar energy, CO(2), and water. Cyanobacterium is therefore a potential novel cell factory for fuels and chemicals production to address global energy security and climate change issues.

Dissociative electron attachments to ethanol and acetaldehyde: A combined experimental and simulation study

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

Wang, Xu-Dong; Xuan, Chuan-Jin; Feng, Wen-Ling

Dissociation dynamics of the temporary negative ions of ethanol and acetaldehyde formed by the low-energy electron attachments is investigated by using the anion velocity map imaging technique and ab initio molecular dynamics simulations. The momentum images of the dominant fragments O{sup −}/OH{sup −} and CH{sub 3}{sup −} are recorded, indicating the low kinetic energies of O{sup −}/OH{sup −} for ethanol while the low and high kinetic energy distributions of O{sup −} ions for acetaldehyde. The CH{sub 3}{sup −} image for acetaldehyde also shows the low kinetic energy. With help of the dynamics simulations, the fragmentation processes are qualitatively clarified. Amore » new cascade dissociation pathway to produce the slow O{sup −} ion via the dehydrogenated intermediate, CH{sub 3}CHO{sup −} (acetaldehyde anion), is proposed for the dissociative electron attachment to ethanol. After the electron attachment to acetaldehyde molecule, the slow CH{sub 3}{sup −} is produced quickly in the two-body dissociation with the internal energy redistributions in different aspects before bond cleavages.« less

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

Hang, Y.D.; Lee, C.Y.; Woodams, E.E.

A solid state fermentation system for the production of ethanol from apple pomace with a Montrachet strain of Saccharomyces cerevisiae is described. The yields of ethanol varied from about 29 g to more than 40 g/kg of apple pomace, depending on the samples fermented. Separation of up to 99% of the ethanol from spent qpple pomace was achieved with a rotary vacuum evaporator. Alcohol fermentation of apple pomace might be an efficient method of alleviating waste disposal problems with the concomitant production of ethanol.

Immobilized anaerobic fermentation for bio-fuel production by Clostridium co-culture.

PubMed

Xu, Lei; Tschirner, Ulrike

2014-08-01

Clostridium thermocellum/Clostridium thermolacticum co-culture fermentation has been shown to be a promising way of producing ethanol from several carbohydrates. In this research, immobilization techniques using sodium alginate and alkali pretreatment were successfully applied on this co-culture to improve the bio-ethanol fermentation performance during consolidated bio-processing (CBP). The ethanol yield obtained increased by over 60 % (as a percentage of the theoretical maximum) as compared to free cell fermentation. For cellobiose under optimized conditions, the ethanol yields were approaching about 85 % of the theoretical efficiency. To examine the feasibility of this immobilization co-culture on lignocellulosic biomass conversion, untreated and pretreated aspen biomasses were also used for fermentation experiments. The immobilized co-culture shows clear benefits in bio-ethanol production in the CBP process using pretreated aspen. With a 3-h, 9 % NaOH pretreatment, the aspen powder fermentation yields approached 78 % of the maximum theoretical efficiency, which is almost twice the yield of the untreated aspen fermentation.

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.

Catalytic Conversion of Carbohydrates to Initial Platform Chemicals: Chemistry and Sustainability.

PubMed

Mika, László T; Cséfalvay, Edit; Németh, Áron

2018-01-24

The replacement of fossil resources that currently provide more than 90% of our energy needs and feedstocks of the chemical industry in combination with reduced emission of carbon dioxide is one of the most pressing challenges of mankind. Biomass as a globally available resource has been proposed as an alternative feedstock for production of basic building blocks, which could partially or even fully replace the currently utilized fossil-based ones in well-established chemical processes. The destruction of lignocellulosic feed followed by oxygen removal from its cellulose and hemicellulose content by catalytic processes results in the formation of initial platform chemicals (IPCs). However, their sustainable production strongly depends on the availability of resources, their efficient or even industrially viable conversion processes, and replenishment time of feedstocks. Herein, we overview recent advances and developments in catalytic transformations of the carbohydrate content of lignocellulosic biomass to IPCs (i.e., ethanol, 3-hydroxypropionic acid, isoprene, succinic and levulinic acids, furfural, and 5-hydroxymethylfurfural). The mechanistic aspects, development of new catalysts, different efficiency indicators (yield and selectivity), and conversion conditions of their production are presented and compared. The potential biochemical production routes utilizing recently engineered microorganisms are reviewed, as well. The sustainability metrics that could be applied to the chemical industry (individual set of sustainability indicators, composite indices methods, material and energy flow analysis-based metrics, and ethanol equivalents) are also overviewed as well as an outlook is provided to highlight challenges and opportunities associated with this huge research area.

BIOSEP: A NEW ETHANOL RECOVERY TECHNOLOGY FOR SMALL SCALE RURAL PRODUCTION OF ETHANOL FROM BIOMASS

EPA Science Inventory

Research activities on bioethanol have increased substantially as a result of the current concerns with energy security. Inexpensive biomass including forest residues, mill residues, agricultural residues, urban wood wastes and dedicated energy corps that exists in abundance acr...

Direct Ethanol Production from Lignocellulosic Sugars and Sugarcane Bagasse by a Recombinant Trichoderma reesei Strain HJ48

PubMed Central

Huang, Jun; Chen, Dong; Wei, Yutuo; Wang, Qingyan; Li, Zhenchong; Chen, Ying; Huang, Ribo

2014-01-01

Trichoderma reesei can be considered as a candidate for consolidated bioprocessing (CBP) microorganism. However, its ethanol yield needs to be improved significantly. Here the ethanol production of T. reesei CICC 40360 was improved by genome shuffling while simultaneously enhancing the ethanol resistance. The initial mutant population was generated by nitrosoguanidine treatment of the spores, and an improved population producing more than fivefold ethanol than wild type was obtained by genome shuffling. The results show that the shuffled strain HJ48 can efficiently convert lignocellulosic sugars to ethanol under aerobic conditions. Furthermore, it was able to produce ethanol directly from sugarcane bagasse, demonstrating that the shuffled strain HJ48 is a suitable microorganism for consolidated bioprocessing. PMID:24995362

Direct ethanol production from lignocellulosic sugars and sugarcane bagasse by a recombinant Trichoderma reesei strain HJ48.

PubMed

Huang, Jun; Chen, Dong; Wei, Yutuo; Wang, Qingyan; Li, Zhenchong; Chen, Ying; Huang, Ribo

2014-01-01

Trichoderma reesei can be considered as a candidate for consolidated bioprocessing (CBP) microorganism. However, its ethanol yield needs to be improved significantly. Here the ethanol production of T. reesei CICC 40360 was improved by genome shuffling while simultaneously enhancing the ethanol resistance. The initial mutant population was generated by nitrosoguanidine treatment of the spores, and an improved population producing more than fivefold ethanol than wild type was obtained by genome shuffling. The results show that the shuffled strain HJ48 can efficiently convert lignocellulosic sugars to ethanol under aerobic conditions. Furthermore, it was able to produce ethanol directly from sugarcane bagasse, demonstrating that the shuffled strain HJ48 is a suitable microorganism for consolidated bioprocessing.

Genetic Modification of Short Rotation Poplar Biomass Feedstock for Efficient Conversion to Ethanol

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

Dinus, R.J.

2000-08-30

The Bioenergy Feedstock Development Program, Environmental Sciences Division, Oak Ridge National Laboratory is developing poplars (Populus species and hybrids) as sources of renewable energy, i.e., ethanol. Notable increases in adaptability, volume productivity, and pest/stress resistance have been achieved via classical selection and breeding and intensified cultural practices. Significant advances have also been made in the efficiencies of harvesting and handling systems. Given these and anticipated accomplishments, program leaders are considering shifting some attention to genetically modifying feedstock physical and chemical properties, so as to improve the efficiency with which feedstocks can be converted to ethanol. This report provides an in-depthmore » review and synthesis of opportunities for and feasibilities of genetically modifying feedstock qualities via classical selection and breeding, marker-aided selection and breeding, and genetic transformation. Information was collected by analysis of the literature, with emphasis on that published since 1995, and interviews with prominent scientists, breeders, and growers. Poplar research is well advanced, and literature is abundant. The report therefore primarily reflects advances in poplars, but data from other species, particularly other shortrotation hardwoods, are incorporated to fill gaps. An executive summary and recommendations for research, development, and technology transfer are provided immediately after the table of contents. The first major section of the report describes processes most likely to be used for conversion of poplar biomass to ethanol, the various physical and chemical properties of poplar feedstocks, and how such properties are expected to affect process efficiency. The need is stressed for improved understanding of the impact of change on both overall process and individual process step efficiencies. The second part documents advances in trait measurement instrumentation and methodology. The importance of these and future developments is emphasized, since trait measurement constitutes the largest cost associated with adding additional traits to improvement efforts, regardless of genetic approach. In subsequent sections, recent and projected advances in classical selection and breeding, marker-aided selection, and genetic transformation are documented and used to evaluate the feasibility of individual approaches. Interviews with specialists engaged in research and development on each approach were given particular emphasis in gauging feasibilities and defining future needs and directions. Summaries of important findings and major conclusions are presented at the end of individual sections. Closing portions describe the targeted workshop, conducted in December 1999 and list interviewees and literature cited in the text. Information obtained at the workshop was used to improve accuracy, refine conclusions, and recommend priorities for future research, development, and technology transfer.« less

%22Trojan Horse%22 strategy for deconstruction of biomass for biofuels production.

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

Simmons, Blake Alexander; Sinclair, Michael B.; Yu, Eizadora

2011-02-01

Production of renewable biofuels to displace fossil fuels currently consumed in the transportation sector is a pressing multiagency national priority (DOE/USDA/EERE). Currently, nearly all fuel ethanol is produced from corn-derived starch. Dedicated 'energy crops' and agricultural waste are preferred long-term solutions for renewable, cheap, and globally available biofuels as they avoid some of the market pressures and secondary greenhouse gas emission challenges currently facing corn ethanol. These sources of lignocellulosic biomass are converted to fermentable sugars using a variety of chemical and thermochemical pretreatments, which disrupt cellulose and lignin cross-links, allowing exogenously added recombinant microbial enzymes to more efficiently hydrolyzemore » the cellulose for 'deconstruction' into glucose. This process is plagued with inefficiencies, primarily due to the recalcitrance of cellulosic biomass, mass transfer issues during deconstruction, and low activity of recombinant deconstruction enzymes. Costs are also high due to the requirement for enzymes and reagents, and energy-intensive cumbersome pretreatment steps. One potential solution to these problems is found in synthetic biology-engineered plants that self-produce a suite of cellulase enzymes. Deconstruction can then be integrated into a one-step process, thereby increasing efficiency (cellulose-cellulase mass-transfer rates) and reducing costs. The unique aspects of our approach are the rationally engineered enzymes which become Trojan horses during pretreatment conditions. During this study we rationally engineered Cazy enzymes and then integrated them into plant cells by multiple transformation techniques. The regenerated plants were assayed for first expression of these messages and then for the resulting proteins. The plants were then subjected to consolidated bioprocessing and characterized in detail. Our results and possible implications of this work on developing dedicated energy crops and their advantage in a consolidated bioprocessing system.« less

Efficient ethanol production from dried oil palm trunk treated by hydrothermolysis and subsequent enzymatic hydrolysis.

PubMed

Eom, In-Yong; Yu, Ju-Hyun; Jung, Chan-Duck; Hong, Kyung-Sik

2015-01-01

Oil palm trunk (OPT) is a valuable bioresource for the biorefinery industry producing biofuels and biochemicals. It has the distinct feature of containing a large amount of starch, which, unlike cellulose, can be easily solubilized by water when heated and hydrolyzed to glucose by amylolytic enzymes without pretreatment for breaking down the biomass recalcitrance. Therefore, it is suggested as beneficial to extract most of the starch from OPT through autoclaving and subsequent amylolytic hydrolysis prior to pretreatment. However, this treatment requires high capital and operational costs, and there could be a high probability of microbial contamination during starch processing. In terms of biochemical conversion of OPT, this study aimed to develop a simple and efficient ethanol conversion process without any chemical use such as acids and bases or detoxification. For comparison with the proposed efficient ethanol conversion process, OPT was subjected to hydrothermal treatment at 180 °C for 30 min. After enzymatic hydrolysis of PWS, 43.5 g of glucose per 100 g dry biomass was obtained, which corresponds to 81.3 % of the theoretical glucose yield. Through subsequent alcohol fermentation, 81.4 % ethanol yield of the theoretical ethanol yield was achieved. To conduct the proposed new process, starch in OPT was converted to ethanol through enzymatic hydrolysis and subsequent fermentation prior to hydrothermal treatment, and the resulting slurry was subjected to identical processes that were applied to control. Consequently, a high-glucose yield of 96.3 % was achieved, and the resulting ethanol yield was 93.5 %. The proposed new process was a simple method for minimizing the loss of starch during biochemical conversion and maximizing ethanol production as well as fermentable sugars from OPT. In addition, this methodology offers the advantage of reducing operational and capital costs due to minimizing the process for ethanol production by excluding expensive processes related to detoxification prior to enzymatic hydrolysis and fermentation such as washing/conditioning and solid-liquid separation of pretreated slurry. The potential future use of xylose-digestible microorganisms could further increase the ethanol yield from the proposed process, thereby increasing its effectiveness for the conversion of OPT into biofuels and biochemicals.

An appealing photo-powered multi-functional energy system for the poly-generation of hydrogen and electricity

NASA Astrophysics Data System (ADS)

Tang, Tiantian; Li, Kan; Shen, Zhemin; Sun, Tonghua; Wang, Yalin; Jia, Jinping

2015-10-01

This paper focuses on a photo-powered poly-generation system (PPS) that is powered by the photocatalytic oxidation of organic substrate to produce hydrogen energy and electrical energy synchronously. This particular device runs entirely on light energy and chemical energy of substrate without external voltage. The performance measurements and optimization experiments are all investigated by using the low concentration of pure ethanol (EtOH) solution. Compared with the conventional submerged reactor for the photogeneration of hydrogen, the hydrogen and the electric current obtained in the constructed PPS are all relatively stable in experimental period and the numerical values detected are many times higher than that of the former by using various simulated ethanol waste liquid. When using Chinese rice wine as substrate at the same ethanol content level (i.e., 0.1 mol L-1), the production of hydrogen is close to that of the pure ethanol solution in the constructed PPS, but no hydrogen is detected in the conventional submerged reactor. These results demonstrate that the constructed PPS could effectively utilize light energy and perform good capability in poly-generation of hydrogen and electricity.

Simultaneous hydrogen and ethanol production from cascade utilization of mono-substrate in integrated dark and photo-fermentative reactor.

PubMed

Liu, Bing-Feng; Xie, Guo-Jun; Wang, Rui-Qing; Xing, De-Feng; Ding, Jie; Zhou, Xu; Ren, Hong-Yu; Ma, Chao; Ren, Nan-Qi

2015-01-01

Integrating hydrogen-producing bacteria with complementary capabilities, dark-fermentative bacteria (DFB) and photo-fermentative bacteria (PFB), is a promising way to completely recover bioenergy from waste biomass. However, the current coupled models always suffer from complicated pretreatment of the effluent from dark-fermentation or imbalance between dark and photo-fermentation, respectively. In this work, an integrated dark and photo-fermentative reactor (IDPFR) was developed to completely convert an organic substrate into bioenergy. In the IDPFR, Ethanoligenens harbinese B49 and Rhodopseudomonas faecalis RLD-53 were separated by a membrane into dark and photo chambers, while the acetate produced by E. harbinese B49 in the dark chamber could freely pass through the membrane into the photo chamber and serve as a carbon source for R. faecalis RLD-53. The hydrogen yield increased with increasing working volume of the photo chamber, and reached 3.38 mol H2/mol glucose at the dark-to-photo chamber ratio of 1:4. Hydrogen production by the IDPFR was also significantly affected by phosphate buffer concentration, glucose concentration, and ratio of dark-photo bacteria. The maximum hydrogen yield (4.96 mol H2/mol glucose) was obtained at a phosphate buffer concentration of 20 mmol/L, a glucose concentration of 8 g/L, and a ratio of dark to photo bacteria of 1:20. As the glucose and acetate were used up by E. harbinese B49 and R. faecalis RLD-53, ethanol produced by E. harbinese B49 was the sole end-product in the effluent from the IDPFR, and the ethanol concentration was 36.53 mmol/L with an ethanol yield of 0.82 mol ethanol/mol glucose. The results indicated that the IDPFR not only circumvented complex pretreatments on the effluent in the two-stage process, but also overcame the imbalance of growth and metabolic rate between DFB and PFB in the co-culture process, and effectively enhanced cooperation between E. harbinense B49 and R. faecalis RLD-53. Moreover, simultaneous hydrogen and ethanol production were achieved by coupling E. harbinese B49 and R. faecalis RLD-53 in the IDPFR. According to stoichiometry, the hydrogen and ethanol production efficiencies were 82.67% and 82.19%, respectively. Therefore, IDPFR was an effective strategy for coupling DFB and PFB to fulfill efficient energy recovery from waste biomass.

Single-step ethanol production from lignocellulose using novel extremely thermophilic bacteria.

PubMed

Svetlitchnyi, Vitali A; Kensch, Oliver; Falkenhan, Doris A; Korseska, Svenja G; Lippert, Nadine; Prinz, Melanie; Sassi, Jamaleddine; Schickor, Anke; Curvers, Simon

2013-02-28

Consolidated bioprocessing (CBP) of lignocellulosic biomass to ethanol using thermophilic bacteria provides a promising solution for efficient lignocellulose conversion without the need for additional cellulolytic enzymes. Most studies on the thermophilic CBP concentrate on co-cultivation of the thermophilic cellulolytic bacterium Clostridium thermocellum with non-cellulolytic thermophilic anaerobes at temperatures of 55°C-60°C. We have specifically screened for cellulolytic bacteria growing at temperatures >70°C to enable direct conversion of lignocellulosic materials into ethanol. Seven new strains of extremely thermophilic anaerobic cellulolytic bacteria of the genus Caldicellulosiruptor and eight new strains of extremely thermophilic xylanolytic/saccharolytic bacteria of the genus Thermoanaerobacter isolated from environmental samples exhibited fast growth at 72°C, extensive lignocellulose degradation and high yield ethanol production on cellulose and pretreated lignocellulosic biomass. Monocultures of Caldicellulosiruptor strains degraded up to 89-97% of the cellulose and hemicellulose polymers in pretreated biomass and produced up to 72 mM ethanol on cellulose without addition of exogenous enzymes. In dual co-cultures of Caldicellulosiruptor strains with Thermoanaerobacter strains the ethanol concentrations rose 2- to 8.2-fold compared to cellulolytic monocultures. A co-culture of Caldicellulosiruptor DIB 087C and Thermoanaerobacter DIB 097X was particularly effective in the conversion of cellulose to ethanol, ethanol comprising 34.8 mol% of the total organic products. In contrast, a co-culture of Caldicellulosiruptor saccharolyticus DSM 8903 and Thermoanaerobacter mathranii subsp. mathranii DSM 11426 produced only low amounts of ethanol. The newly discovered Caldicellulosiruptor sp. strain DIB 004C was capable of producing unexpectedly large amounts of ethanol from lignocellulose in fermentors. The established co-cultures of new Caldicellulosiruptor strains with new Thermoanaerobacter strains underline the importance of using specific strain combinations for high ethanol yields. These co-cultures provide an efficient CBP pathway for ethanol production and represent an ideal starting point for development of a highly integrated commercial ethanol production process.

The Potential Environmental Impact of Waste from Cellulosic Ethanol Production

EPA Science Inventory

The increasing production of ethanol has been established as an important contributor to future energy independence. A trend in decreasing profitability and resource conflicts has given grain based ethanol production a limited and difficult future. Growing emphasis is being place...

SEPARATION AND CONCENTRATION OF ETHANOL BY PERVAPORATION

EPA Science Inventory

A significant issue affecting widespread acceptance of bioethanol as a sustainable fuel is the energy used to grow the feedstock, ferment the feedstock to ethanol, and separate dry ethanol from the fermentation broth. For the latter, the best current technology is two-step disti...

Simultaneous Saccharification and Fermentation of Sugar Beet Pulp for Efficient Bioethanol Production

PubMed Central

Berłowska, Joanna; Balcerek, Maria; Dziekońska-Kubczak, Urszula; Patelski, Piotr; Dziugan, Piotr

2016-01-01

Sugar beet pulp, a byproduct of sugar beet processing, can be used as a feedstock in second-generation ethanol production. The objective of this study was to investigate the effects of pretreatment, of the dosage of cellulase and hemicellulase enzyme preparations used, and of aeration on the release of fermentable sugars and ethanol yield during simultaneous saccharification and fermentation (SSF) of sugar beet pulp-based worts. Pressure-thermal pretreatment was applied to sugar beet pulp suspended in 2% w/w sulphuric acid solution at a ratio providing 12% dry matter. Enzymatic hydrolysis was conducted using Viscozyme and Ultraflo Max (Novozymes) enzyme preparations (0.015–0.02 mL/g dry matter). Two yeast strains were used for fermentation: Ethanol Red (S. cerevisiae) (1 g/L) and Pichia stipitis (0.5 g/L), applied sequentially. The results show that efficient simultaneous saccharification and fermentation of sugar beet pulp was achieved. A 6 h interval for enzymatic activation between the application of enzyme preparations and inoculation with Ethanol Red further improved the fermentation performance, with the highest ethanol concentration reaching 26.9 ± 1.2 g/L and 86.5 ± 2.1% fermentation efficiency relative to the theoretical yield. PMID:27722169

Branched-chain higher alcohols.

PubMed

Wang, Bao-Wei; Shi, Ai-Qin; Tu, Ran; Zhang, Xue-Li; Wang, Qin-Hong; Bai, Feng-Wu

2012-01-01

China's energy requirements and environmental concerns have stimulated efforts toward developing alternative liquid fuels. Compared with fuel ethanol, branched-chain higher alcohols (BCHAs), including isopropanol, isobutanol, 2-methyl-1-butanol, and 3-methyl-1-butanol, exhibit significant advantages, such as higher energy density, lower hygroscopicity, lower vapor pressure, and compatibility with existing transportation infrastructures. However, BCHAs have not been synthesized economically using native organisms, and thus their microbial production based on metabolic engineering and synthetic biology offers an alternative approach, which presents great potential for improving production efficiency. We review the current status of production and consumption of BCHAs and research progress regarding their microbial production in China, especially with the combination of metabolic engineering and synthetic biology.

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.

Process of concentrating ethanol from dilute aqueous solutions thereof

DOEpatents

Oulman, C.S.; Chriswell, C.D.

1981-07-07

Relatively dilute aqueous solutions of ethanol are concentrated by passage through a bed of a crystalline silica polymorph, such as silicalite, to adsorb the ethanol with residual dilute feed in contact with the bed, which is displaced by passing concentrated aqueous ethanol through the bed without displacing the adsorbed ethanol. A product concentrate is then obtained by removing the adsorbed ethanol from the bed together with at least a portion of the concentrated aqueous ethanol used as the displacer liquid. This process permits ethanol to be concentrated from dilute fermentation beers, which may contain from 6 to 10% ethanol, to obtain a concentrate product at very low energy cost having an ethanol concentration in excess of 95%, such as a concentration of from 98 to 99.5%. 5 figs.

Process of concentrating ethanol from dilute aqueous solutions thereof

DOEpatents

Oulman, Charles S. [Ames, IA; Chriswell, Colin D. [Slater, IA

1981-07-07

Relatively dilute aqueous solutions of ethanol are concentrated by passage through a bed of a crystalline silica polymorph, such as silicalite, to adsorb the ethanol with residual dilute feed in contact with the bed, which is displaced by passing concentrated aqueous ethanol through the bed without displacing the adsorbed ethanol. A product concentrate is then obtained by removing the adsorbed ethanol from the bed together with at least a portion of the concentrated aqueous ethanol used as the displacer liquid. This process permits ethanol to be concentrated from dilute fermentation beers, which may contain from 6 to 10% ethanol, to obtain a concentrate product at very low energy cost having an ethanol concentration in excess of 95%, such as a concentration of from 98 to 99.5%.

Thermodynamics of R-(+)-2-(4-Hydroxyphenoxy)propanoic Acid Dissolution in Methanol, Ethanol, and Methanol-Ethanol Mixture

NASA Astrophysics Data System (ADS)

Liu, Wei; Ma, Jinju; Yao, Xinding; Fang, Ruina; Cheng, Liang

2018-05-01

The solubilities of R-(+)-2-(4-hydroxyphenoxy)propanoic acid (D-HPPA) in methanol, ethanol and various methanol-ethanol mixtures are determined in the temperature range from 273.15 to 323.15 K at atmospheric pressure using a laser detecting system. The solubilities of D-HPPA increase with increasing mole fraction of ethanol in the methanol-ethanol mixtures. Experimental data were correlated with Buchowski-Ksiazczak λ h equation and modified Apelblat equation; the first one gives better approximation for the experimental results. The enthalpy, entropy and Gibbs free energy of D-HPPA dissolution in methanol, ethanol and methanol-ethanol mixtures were also calculated from the solubility data.

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.

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...

Solar-Energy Driven Simultaneous Saccharification and Fermentation of Starch to Bioethanol for Fuel-Cell Applications.

PubMed

Tabah, Betina; Pulidindi, Indra Neel; Chitturi, Venkateswara Rao; Arava, Leela Mohana Reddy; Gedanken, Aharon

2015-10-26

A solar reactor was designed to perform the conversion of starch to ethanol in a single step. An aqueous starch solution (5 wt %) was fed into the reactor bed charged with Baker's yeast (Saccharomyces cerevisiae) and amylase, resulting in approximately 2.5 wt % ethanol collected daily (ca. 25 mL day(-1) ). A significant amount of ethanol (38 g) was collected over 63 days, corresponding to 84 % of the theoretical yield. The production of ethanol without additional energy input highlights the significance of this new process. The ethanol produced was also demonstrated as a potential fuel for direct ethanol fuel cells. Additionally, the secondary metabolite glycerol was fully reduced to a value-added product 1,3-propanediol, which is the first example of a fungal strain (Baker's yeast) converting glycerol in situ to 1,3-propanediol. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enhancement of ethanol production from green liquor-ethanol-pretreated sugarcane bagasse by glucose-xylose cofermentation at high solid loadings with mixed Saccharomyces cerevisiae strains.

PubMed

You, Yanzhi; Li, Pengfei; Lei, Fuhou; Xing, Yang; Jiang, Jianxin

2017-01-01

Efficient cofermentation of glucose and xylose is necessary for economically feasible bioethanol production from lignocellulosic biomass. Here, we demonstrate pretreatment of sugarcane bagasse (SCB) with green liquor (GL) combined with ethanol (GL-Ethanol) by adding different GL amounts. The common Saccharomyces cerevisiae (CSC) and thermophilic S. cerevisiae (TSC) strains were used and different yeast cell mass ratios (CSC to TSC) were compared. The simultaneous saccharification and cofermentation (SSF/SSCF) process was performed by 5-20% (w/v) dry substrate (DS) solid loadings to determine optimal conditions for the co-consumption of glucose and xylose. Compared to previous studies that tested fermentation of glucose using only the CSC, we obtained higher ethanol yield and concentration (92.80% and 23.22 g/L) with 1.5 mL GL/g-DS GL-Ethanol-pretreated SCB at 5% (w/v) solid loading and a CSC-to-TSC yeast cell mass ratio of 1:2 (w/w). Using 10% (w/v) solid loading under the same conditions, the ethanol concentration increased to 42.53 g/L but the ethanol yield decreased to 84.99%. In addition, an increase in the solid loading up to a certain point led to an increase in the ethanol concentration from 1.5 mL GL/g-DS-pretreated SCB. The highest ethanol concentration (68.24 g/L) was obtained with 15% (w/v) solid loading, using a CSC-to-TSC yeast cell mass ratio of 1:3 (w/w). GL-Ethanol pretreatment is a promising pretreatment method for improving both glucan and xylan conversion efficiencies of SCB. There was a competitive relationship between the two yeast strains, and the glucose and xylose utilization ability of the TSC was better than that of the CSC. Ethanol concentration was obviously increased at high solid loading, but the yield decreased as a result of an increase in the viscosity and inhibitor levels in the fermentation system. Finally, the SSCF of GL-Ethanol-pretreated SCB with mixed S. cerevisiae strains increased ethanol concentration and was an effective conversion process for ethanol production at high solid loading.

AntogomiR-451 protects human gastric epithelial cells from ethanol via activating AMPK signaling.

PubMed

Zhu, Huanhuan; Zhang, Linjie; Xu, Jianmin; Zhu, Chunhua; Zhao, Hui; Zhu, Yongkang; Lv, Guoqiang

2018-02-26

The prevention and treatment efficiency of ethanol-induced gastric epithelial injury are not satisfied. We have previously shown that AMP-activated protein kinase (AMPK) activation exerts a pro-survival function in human gastric epithelial cells (GECs). miroRNA-451 ("miR-451")'s inhibitor, antagomiR-451, can activate AMPK signaling. In the present study, we show that forced-expression of antagomiR-451 via a lentiviral vector depleted miR-451, leading to AMPK activation in established GES-1 cells and primary human GECs. AntagomiR-451 efficiently protected GES-1 cells and primary human GECs from ethanol-induced viability reduction and apoptosis. AMPK activation is required for antagomiR-451-induced GEC protection. AMPKα1 knockdown (by targeted-shRNAs) or knockout (by CRISPR-Cas-9 KO plasmid) blocked antagomiR-451-induced AMPK activation, and GEC protection against ethanol. Further experimental results show that antagomiR-451 significantly attenuated ethanol-induced reactive oxygen species (ROS) production, lipid peroxidation and DNA damage. Collectively, antagomiR-451 protects human GECs from ethanol via activating AMPK signaling. Copyright © 2018 Elsevier Inc. All rights reserved.

Utilization of recombinant Trichoderma reesei expressing Aspergillus aculeatus β-glucosidase I (JN11) for a more economical production of ethanol from lignocellulosic biomass.

PubMed

Treebupachatsakul, Treesukon; Shioya, Koki; Nakazawa, Hikaru; Kawaguchi, Takashi; Morikawa, Yasushi; Shida, Yosuke; Ogasawara, Wataru; Okada, Hirofumi

2015-12-01

The capacity of Trichoderma reesei cellulase to degrade lignocellulosic biomass has been enhanced by the construction of a recombinant T. reesei strain expressing Aspergillus aculeatus β-glucosidase I. We have confirmed highly efficient ethanol production from converge-milled Japanese cedar by recombinant T. reesei expressing A. aculeatus β-glucosidase I (JN11). We investigated the ethanol productivity of JN11 and compared it with the cocktail enzyme T. reesei PC-3-7 with reinforced cellobiase activity by the commercial Novozyme 188. Results showed that the ethanol production efficiency under enzymatic hydrolysis of JN11 was comparable to the cocktail enzyme both on simultaneous saccharification and fermentation (SSF) or separate hydrolysis and fermentation (SHF) processes. Moreover, the cocktail enzyme required more protein loading for attaining similar levels of ethanol conversion as JN11. We propose that JN11 is an intrinsically economical enzyme that can eliminate the supplementation of BGL for PC-3-7, thereby reducing the cost of industrial ethanol production from lignocellulosic biomass. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

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.

Potential impact of Thailand's alcohol program on production, consumption, and trade of cassava, sugarcane, and corn

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

Boonserm, P.

1985-01-01

On the first of May 1980, Thailand's fuel-alcohol program was announced by the Thai government. According to the program, a target of 147 million liters of ethanol would be produced in 1981, from cassava, sugarcane, and other biomasses. Projecting increases in output each year, the target level of ethanol produciton was set at 482 million liters of ethanol for 1986. The proposed amount of ethanol production could create a major shift up in the demand schedule of energy crops such as cassava, sugarcane, and corn. The extent of the adjustments in price, production, consumption, and exports for these energy cropsmore » need to be evaluated. The purpose of this study is to assess the potential impact of Thailand's fuel-alcohol program on price, production, consumption, and exports of three potential energy crops: cassava, sugarcane, and corn. Econometric commodity models of cassava, sugarcane, and corn are constructed and used as a method of assessment. The overall results of the forecasting simulations of the models indicate that the fuel-alcohol program proposed by the Thai government will cause the price, production, and total consumption of cassava, sugarcane, and corn to increase; on the other hand, it will cause exports to decline. In addition, based on the relative prices and the technical coefficients of ethanol production of these three energy crops, this study concludes that only cassava should be used to produce the proposed target of ethanol production.« less

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

Pihl, Josh A.; Toops, Todd J.; Fisher, Galen B.

Lean gasoline engines running on ethanol/gasoline blends and equipped with a silver/alumina catalyst for selective catalytic reduction (SCR) of NO by ethanol provide a pathway to reduced petroleum consumption through both increased biofuel utilization and improved engine efficiency relative to the current stoichiometric gasoline engines that dominate the U.S. light duty vehicle fleet. A pre-commercial silver/alumina catalyst demonstrated high NO x conversions over a moderate temperature window with both neat ethanol and ethanol/gasoline blends containing at least 50% ethanol. Selectivity to NH 3 increases with HC dosing and ethanol content in gasoline blends, but appears to saturate at around 45%.more » NO 2 and acetaldehyde behave like intermediates in the ethanol SCR of NO. NH 3 SCR of NO x does not appear to play a major role in the ethanol SCR reaction mechanism. Ethanol is responsible for the low temperature SCR activity observed with the ethanol/gasoline blends. In conclusion, the gasoline HCs do not deactivate the catalyst ethanol SCR activity, but they also do not appear to be significantly activated by the presence of ethanol.« less

[Application of continuous mixing technology in ethanol precipitation process of Salvia miltiorrhiza by using micromixer].

PubMed

Gong, Xing-Chu; Shen, Ji-Chen; Qu, Hai-Bin

2016-12-01

Continuous pharmaceutical manufacturing is one of the development directions in international pharmaceutical technology. In this study, a continuous mixing technology of ethanol and concentrated extract in the ethanol precipitation of Salvia miltiorrhiza was realized by using a membrane dispersion method. The effects of ethanol flowrate, concentrated extract flowrate, and flowrate ratio on ethanol precipitation results were investigated. With the increase of the flowrates of ethanol and concentrated extract, retention rate of active phenolic acids components was increased, and the total solid removal rate was decreased. The purity of active components in supernatants was mainly affected by the ratio of ethanol flowrate and concentrated extract flowrate. The mixing efficiency of adding ethanol under continuous flow mixing mode in this study was comparable to that of industrial ethanol precipitation. Continuous adding ethanol by using a membrane dispersion mixer is a promising technology with many advantages such as easy enlargement, large production per unit volume, and easy control. Copyright© by the Chinese Pharmaceutical Association.

Life cycle assessment of fuel ethanol produced from soluble sugar in sweet sorghum stalks in North China

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

Ding, Ning; Yang, Yang; Cai, Hao

This paper describes the results of a life cycle assessment of sweet sorghum stalk (SSS)-based ethanol in North China. We determined the environmental performance of SSS-based ethanol and examined its advantages and disadvantages, as compared to gasoline, focusing on the life cycle of feedstock production, transportation, ethanol production and distribution, and use. The GREET transportation model and the method developed by the Centre of Environmental Sciences at Leiden University (CML method) were used to compile a life cycle inventory and to assess environmental impacts. Results indicate that SSS-based ethanol has advantages in terms of energy consumption, with a well tomore » wheel decrease of 85% fossil energy and 44% global warming potential, as compared with gasoline. Abiotic depletion potential, acidification potential, and photochemical ozone creation potential were also 50–90% lower than in the case of gasoline, while human health toxic potential was 36% lower. However, SSS-based sorghum did not have advantages over gasoline in terms of life cycle cost, land use, and water consumption. Results indicate that such an evaluation cannot just consider a few types of environmental impacts, researchers should promote systematic and comprehensive life cycle assessment of ethanol to guide the development of an energy strategy for China.« less

Integrated Process for Ethanol, Biogas, and Edible Filamentous Fungi-Based Animal Feed Production from Dilute Phosphoric Acid-Pretreated Wheat Straw.

PubMed

Nair, Ramkumar B; Kabir, Maryam M; Lennartsson, Patrik R; Taherzadeh, Mohammad J; Horváth, Ilona Sárvári

2018-01-01

Integration of wheat straw for a biorefinery-based energy generation process by producing ethanol and biogas together with the production of high-protein fungal biomass (suitable for feed application) was the main focus of the present study. An edible ascomycete fungal strain Neurospora intermedia was used for the ethanol fermentation and subsequent biomass production from dilute phosphoric acid (0.7 to 1.2% w/v) pretreated wheat straw. At optimum pretreatment conditions, an ethanol yield of 84 to 90% of the theoretical maximum, based on glucan content of substrate straw, was observed from fungal fermentation post the enzymatic hydrolysis process. The biogas production from the pretreated straw slurry showed an improved methane yield potential up to 162% increase, as compared to that of the untreated straw. Additional biogas production, using the syrup, a waste stream obtained post the ethanol fermentation, resulted in a combined total energy output of 15.8 MJ/kg wheat straw. Moreover, using thin stillage (a waste stream from the first-generation wheat-based ethanol process) as a co-substrate to the biogas process resulted in an additional increase by about 14 to 27% in the total energy output as compared to using only wheat straw-based substrates. ᅟ.

Nitrogen rate and landscape impacts on life cycle energy use and emissions from switchgrass-derived ethanol

DOE PAGES

Mbonimpa, Eric G.; Kumar, Sandeep; Owens, Vance N.; ...

2015-08-24

Switchgrass-derived ethanol has been proposed as an alternative to fossil fuels to improve sustainability of the US energy sector. In this study, life cycle analysis (LCA) was used to estimate the environmental benefits of this fuel. To better define the LCA environmental impacts associated with fertilization rates and farm-landscape topography, results from a controlled experiment were analyzed. Data from switchgrass plots planted in 2008, consistently managed with three nitrogen rates (0, 56, and 112 kg N ha –1), two landscape positions (shoulder and footslope), and harvested annually (starting in 2009, the year after planting) through 2014 were used as inputmore » into the Greenhouse gases, Regulated Emissions and Energy use in transportation (GREET) model. Simulations determined nitrogen (N) rate and landscape impacts on the life cycle energy and emissions from switchgrass ethanol used in a passenger car as ethanol–gasoline blends (10% ethanol:E10, 85% ethanol:E85s). Results indicated that E85s may lead to lower fossil fuels use (58 to 77%), greenhouse gas (GHG) emissions (33 to 82%), and particulate matter (PM2.5) emissions (15 to 54%) in comparison with gasoline. However, volatile organic compounds (VOCs) and other criteria pollutants such as nitrogen oxides (NOx), particulate matter (PM10), and sulfur dioxides (SO x) were higher for E85s than those from gasoline. Nitrogen rate above 56 kg N ha –1 yielded no increased biomass production benefits; but did increase (up to twofold) GHG, VOCs, and criteria pollutants. Lower blend (E10) results were closely similar to those from gasoline. The landscape topography also influenced life cycle impacts. Biomass grown at the footslope of fertilized plots led to higher switchgrass biomass yield, lower GHG, VOCs, and criteria pollutants in comparison with those at the shoulder position. Lastly, results also showed that replacing switchgrass before maximum stand life (10–20 years.) can further reduce the energy and emissions reduction benefits.« less

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

Integrated photocatalytic filtration array for indoor air quality control.

PubMed

Denny, Frans; Permana, Eric; Scott, Jason; Wang, Jing; Pui, David Y H; Amal, Rose

2010-07-15

Photocatalytic and filtration technologies were integrated to develop a hybrid system capable of removing and oxidizing organic pollutants from an air stream. A fluidized bed aerosol generator (FBAG) was adapted to prepare TiO(2)-loaded ventilation filters for the photodegradation of gas phase ethanol. Compared to a manually loaded filter, the ethanol photodegradation rate constant for the FBAG coated filter increased by 361%. Additionally, the presence of the photogenerated intermediate product, acetaldehyde, was reduced and the time for mineralization to CO(2) was accelerated. These improvements were attributed to the FBAG system providing a more uniform distribution of TiO(2) particles across the filter surface leading to greater accessibility by the UV light. A dual-UV-lamp system, as opposed to a single-lamp system, enhanced photocatalytic filter performance demonstrating the importance of high light irradiance and light distribution across the filter surface. Substituting the blacklight blue lamps with a UV-light-emitting-diode (UV-LED) array led to further improvement as well as suppressed the electrical energy per order (EE/O) by a factor of 6. These improvements derived from the more uniform distribution of light irradiance as well as the higher efficiency of UV-LEDs in converting electrical energy to photons.

Heat integrated ethanol dehydration flowsheets

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

Hutahaean, L.S.; Shen, W.H.; Brunt, V. Van

1995-04-01

zA theoretical evaluation of heat-integrated heterogeneous-azeotropic ethanol-water distillation flowsheets is presented. Simulations of two column flowsheets using several different hydrocarbon entrainers reveal a region of potential heat integration and substantial reduction in operating energy. In this paper, methods for comparing hydrocarbon entrainers are shown. Two aspects of entrainers are related to operating and capital costs. The binary azeotropic composition of the entrainer-ethanol mixture is related to the energy requirements of the flowsheet. A temperature difference in the azeotrophic column is related to the size of the column and overall process staging requirements. Although the hydrophobicity of an entrainer is essentialmore » for specification of staging in the dehydration column, no substantial increase in operating energy results from an entrainer that has a higher water content. Likewise, liquid-liquid equilibria between several entrainer-ethanol-water mixtures have no substantial effect on either staging or operation. Rather, increasing the alcohol content of the entrainer-ethanol azeotrope limits its recovery in the dehydration column, and increases the recycle and reflux streams. These effects both contribute to increasing the separation energy requirements and reducing the region of potential heat integration. A cost comparison with a multieffect extractive distillation flowsheet reveals that the costs are comparable; however, the extractive distillation flowsheet is more cost effective as operating costs increase.« less

Influence of corn oil recovery on life-cycle greenhouse gas emissions of corn ethanol and corn oil biodiesel.

PubMed

Wang, Zhichao; Dunn, Jennifer B; Han, Jeongwoo; Wang, Michael Q

2015-01-01

Corn oil recovery and conversion to biodiesel has been widely adopted at corn ethanol plants recently. The US EPA has projected 2.6 billion liters of biodiesel will be produced from corn oil in 2022. Corn oil biodiesel may qualify for federal renewable identification number (RIN) credits under the Renewable Fuel Standard, as well as for low greenhouse gas (GHG) emission intensity credits under California's Low Carbon Fuel Standard. Because multiple products [ethanol, biodiesel, and distiller's grain with solubles (DGS)] are produced from one feedstock (corn), however, a careful co-product treatment approach is required to accurately estimate GHG intensities of both ethanol and corn oil biodiesel and to avoid double counting of benefits associated with corn oil biodiesel production. This study develops four co-product treatment methods: (1) displacement, (2) marginal, (3) hybrid allocation, and (4) process-level energy allocation. Life-cycle GHG emissions for corn oil biodiesel were more sensitive to the choice of co-product allocation method because significantly less corn oil biodiesel is produced than corn ethanol at a dry mill. Corn ethanol life-cycle GHG emissions with the displacement, marginal, and hybrid allocation approaches are similar (61, 62, and 59 g CO2e/MJ, respectively). Although corn ethanol and DGS share upstream farming and conversion burdens in both the hybrid and process-level energy allocation methods, DGS bears a higher burden in the latter because it has lower energy content per selling price as compared to corn ethanol. As a result, with the process-level allocation approach, ethanol's life-cycle GHG emissions are lower at 46 g CO2e/MJ. Corn oil biodiesel life-cycle GHG emissions from the marginal, hybrid allocation, and process-level energy allocation methods were 14, 59, and 45 g CO2e/MJ, respectively. Sensitivity analyses were conducted to investigate the influence corn oil yield, soy biodiesel, and defatted DGS displacement credits, and energy consumption for corn oil production and corn oil biodiesel production. This study's results demonstrate that co-product treatment methodology strongly influences corn oil biodiesel life-cycle GHG emissions and can affect how this fuel is treated under the Renewable Fuel and Low Carbon Fuel Standards.

Biofuel effect on flame propagation and soot formation in a DISI engine

NASA Astrophysics Data System (ADS)

Irimescu, A.; Merola, S. S.; Di Iorio, S.; Vaglieco, B. M.

2017-10-01

The use of biofuels, especially in transportation and industrial processes, is seen as one of the most effective solutions to promote the reduction of greenhouse gases and pollutant emissions, as well as to lighten the dependence from petro-fuel producers. Biofuels are defined as a wide range of energy sources derived from biomass. In this category, alcohols produced through fermentation, such as ethanol and butanol, are considered some of the most suitable alternatives for transportation purposes. The benefits of bio-ethanol addition to gasoline have always been recognized for practical reasons. Apart from the variety of sources which it can be produced from, ethanol can raise the octane rating, given its improved anti-knock characteristics, allowing the use of higher compression ratios and higher thermal efficiency. However, ethanol’s high latent heat of vaporization can cause problems during cold-start due to poor evaporation. On the other hand, in hot climates ethanol fuelling can result in adverse effects such as vapour lock. Butanol can be considered as an emergent alternative fuel. Normal butanol has several well-known advantages when compared to ethanol, including increased energy content, greater miscibility with transportation fuels, and lower propensity for water absorption. Despite of these pros, the costs of n-butanol production are higher due to lower yields compared to ethanol. Moreover, vaporization remains a critical aspect of this biofuel. Understanding the effect of biofuels on in-cylinder combustion processes is a key-point for the optimization of fuel flexibility and achieving lower CO2 emissions. To this aim, a combined thermodynamic and optical investigation was performed on a direct injection spark ignition engine fuelled with ethanol, butanol and gasoline. Fuels were compared by fixing the injection and spark ignition strategies. Thermodynamic measurements were coupled with optical investigations based on cycle resolved flame visualization. Optimized procedures of image processing were applied to follow the evolution of the flame front in terms of morphological parameters and to evaluate the local distribution of diffusive flames induced by oxidation of fuel deposits during late combustion. These data were correlated with exhaust gas measurements. The experiments confirmed that the chemical-physical specifications of the tested fuels strongly influenced the temporal and spatial evolution of the flame front. Moreover, different distributions and intensities of diffusive flames were observed. These results demonstrated the effect of the fuel on the deposits amount and distribution in the combustion chamber, at fixed operative conditions.

EPA Research on Health Effects of Biofuels: Studies with inhaled ethanol in rats.

EPA Science Inventory

The Energy Independence and Security Act of 2007 mandates increased use of alternative fuels in the American automobile fleet. Currently, the primary alternative to petroleum fuels is ethanol, and the public health risk associated with adding ethanol to gasoline at concentrations...

Biofuels health research at the EPA: Initial studies with inhaled ethanol in rats.

EPA Science Inventory

The Energy Independence and Security Act of 2007 mandates increased use of alternative fuels in the American automobile fleet. Currently, the primary alternative to petroleum fuels is ethanol, and the public health risk associated with adding ethanol to gasoline at concentrations...

Final Report: Utilizing Alternative Fuel Ignition Properties to Improve SI and CI Engine Efficiency

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

Wooldridge, Margaret; Boehman, Andre; Lavoie, George

Experimental and modeling studies were completed to explore leveraging physical and chemical fuel properties for improved thermal efficiency of internal combustion engines. Fundamental studies of the ignition chemistry of ethanol and iso-octane blends and constant volume spray chamber studies of gasoline and diesel sprays supported the core research effort which used several reciprocating engine platforms. Single cylinder spark ignition (SI) engine studies were carried out to characterize the impact of ethanol/gasoline, syngas (H 2 and CO)/gasoline and other oxygenate/gasoline blends on engine performance. The results of the single-cylinder engine experiments and other data from the literature were used to trainmore » a GT Power model and to develop a knock criteria based on reaction chemistry. The models were used to interpret the experimental results and project future performance. Studies were also carried out using a state of the art, direct injection (DI) turbocharged multi- cylinder engine with piezo-actuated fuel injectors to demonstrate the promising spray and spark timing strategies from single-cylinder engine studies on the multi-cylinder engine. Key outcomes and conclusions of the studies were: 1. Efficiency benefits of ethanol and gasoline fuel blends were consistent and substantial (e.g. 5-8% absolute improvement in gross indicated thermal efficiency (GITE)). 2. The best ethanol/gasoline blend (based on maximum thermal efficiency) was determined by the engine hardware and limits based on component protection (e.g. peak in-cylinder pressure or maximum turbocharger inlet temperature) – and not by knock limits. Blends with <50% ethanol delivered significant thermal efficiency gains with conventional SI hardware while maintain good safety integrity to the engine hardware. 3. Other compositions of fuel blends including syngas (H 2 and CO) and other dilution strategies provided significant efficiency gains as well (e.g. 5% absolute improvement in ITE). 4. When the combination of engine and fuel system is not knock limited, multiple fuel injection events maintain thermal efficiency while improving engine-out emissions (e.g. CO, UHC, and particulate number).« less

Countercurrent extraction of soluble sugars from almond hulls and assessment of the bioenergy potential.

PubMed

Holtman, Kevin M; Offeman, Richard D; Franqui-Villanueva, Diana; Bayati, Andre K; Orts, William J

2015-03-11

Almond hulls contain considerable proportions (37% by dry weight) of water-soluble, fermentable sugars (sucrose, glucose, and fructose), which can be extracted for industrial purposes. The maximum optimal solids loading was determined to be 20% for sugar extraction, and the addition of 0.5% (w/v) pectinase aided in maintaining a sufficient free water volume for sugar recovery. A laboratory countercurrent extraction experiment utilizing a 1 h steep followed by three extraction (wash) stages produced a high-concentration (131 g/L fermentable sugar) syrup. Overall, sugar recovery efficiency was 88%. The inner stage washing efficiencies were compatible with solution equilibrium calculations, indicating that efficiency was high. The concentrated sugar syrup was fermented to ethanol at high efficiency (86% conversion), and ethanol concentrations in the broth were 7.4% (v/v). Thin stillage contained 233 g SCOD/L, which was converted to biomethane at an efficiency of 90% with a biomethane potential of 297 mL/g SCODdestroyed. Overall, results suggested that a minima of 49 gal (185 L) ethanol and 75 m(3) methane/t hulls (dry whole hull basis) are achievable.

Energy Potential of Biomass from Conservation Grasslands in Minnesota, USA

PubMed Central

Jungers, Jacob M.; Fargione, Joseph E.; Sheaffer, Craig C.; Wyse, Donald L.; Lehman, Clarence

2013-01-01

Perennial biomass from grasslands managed for conservation of soil and biodiversity can be harvested for bioenergy. Until now, the quantity and quality of harvestable biomass from conservation grasslands in Minnesota, USA, was not known, and the factors that affect bioenergy potential from these systems have not been identified. We measured biomass yield, theoretical ethanol conversion efficiency, and plant tissue nitrogen (N) as metrics of bioenergy potential from mixed-species conservation grasslands harvested with commercial-scale equipment. With three years of data, we used mixed-effects models to determine factors that influence bioenergy potential. Sixty conservation grassland plots, each about 8 ha in size, were distributed among three locations in Minnesota. Harvest treatments were applied annually in autumn as a completely randomized block design. Biomass yield ranged from 0.5 to 5.7 Mg ha−1. May precipitation increased biomass yield while precipitation in all other growing season months showed no affect. Averaged across all locations and years, theoretical ethanol conversion efficiency was 450 l Mg−1 and the concentration of plant N was 7.1 g kg−1, both similar to dedicated herbaceous bioenergy crops such as switchgrass. Biomass yield did not decline in the second or third year of harvest. Across years, biomass yields fluctuated 23% around the average. Surprisingly, forb cover was a better predictor of biomass yield than warm-season grass with a positive correlation with biomass yield in the south and a negative correlation at other locations. Variation in land ethanol yield was almost exclusively due to variation in biomass yield rather than biomass quality; therefore, efforts to increase biomass yield might be more economical than altering biomass composition when managing conservation grasslands for ethanol production. Our measurements of bioenergy potential, and the factors that control it, can serve as parameters for assessing the economic viability of harvesting conservation grasslands for bioenergy. PMID:23577208

Metabolomics-based prediction models of yeast strains for screening of metabolites contributing to ethanol stress tolerance

NASA Astrophysics Data System (ADS)

Hashim, Z.; Fukusaki, E.

2016-06-01

The increased demand for clean, sustainable and renewable energy resources has driven the development of various microbial systems to produce biofuels. One of such systems is the ethanol-producing yeast. Although yeast produces ethanol naturally using its native pathways, production yield is low and requires improvement for commercial biofuel production. Moreover, ethanol is toxic to yeast and thus ethanol tolerance should be improved to further enhance ethanol production. In this study, we employed metabolomics-based strategy using 30 single-gene deleted yeast strains to construct multivariate models for ethanol tolerance and screen metabolites that relate to ethanol sensitivity/tolerance. The information obtained from this study can be used as an input for strain improvement via metabolic engineering.

Metabolic engineering of Saccharomyces cerevisiae ethanol strains PE-2 and CAT-1 for efficient lignocellulosic fermentation.

PubMed

Romaní, Aloia; Pereira, Filipa; Johansson, Björn; Domingues, Lucília

2015-03-01

In this work, Saccharomyces cerevisiae strains PE-2 and CAT-1, commonly used in the Brazilian fuel ethanol industry, were engineered for xylose fermentation, where the first fermented xylose faster than the latter, but also produced considerable amounts of xylitol. An engineered PE-2 strain (MEC1121) efficiently consumed xylose in presence of inhibitors both in synthetic and corn-cob hydrolysates. Interestingly, the S. cerevisiae MEC1121 consumed xylose and glucose simultaneously, while a CEN.PK based strain consumed glucose and xylose sequentially. Deletion of the aldose reductase GRE3 lowered xylitol production to undetectable levels and increased xylose consumption rate which led to higher final ethanol concentrations. Fermentation of corn-cob hydrolysate using this strain, MEC1133, resulted in an ethanol yield of 0.47 g/g of total sugars which is 92% of the theoretical yield. Copyright © 2014 Elsevier Ltd. All rights reserved.

Coefficients of interphase distribution and Gibbs energy of the transfer of nicotinic acid from water into aqueous solutions of ethanol and dimethylsulfoxide

NASA Astrophysics Data System (ADS)

Grazhdan, K. V.; Gamov, G. A.; Dushina, S. V.; Sharnin, V. A.

2012-11-01

Coefficients of the interphase distribution of nicotinic acid are determined in aqueous solution systems of ethanol-hexane and DMSO-hexane at 25.0 ± 0.1°C. They are used to calculate the Gibbs energy of the transfer of nicotinic acid from water into aqueous solutions of ethanol and dimethylsulfoxide. The Gibbs energy values for the transfer of the molecular and zwitterionic forms of nicotinic acid are obtained by means of UV spectroscopy. The diametrically opposite effect of the composition of binary solvents on the transfer of the molecular and zwitterionic forms of nicotinic acid is noted.

Detrimental effect of increasing sugar concentrations on ethanol production from maize or decorticated sorghum mashes fermented with Saccharomyces cerevisiae or Zymomonas mobilis: biofuels and environmental biotechnology.

PubMed

Pérez-Carrillo, Esther; Luisa Cortés-Callejas, M; Sabillón-Galeas, Luis E; Montalvo-Villarreal, Jorge L; Canizo, Jesica R; Georgina Moreno-Zepeda, M; Serna-Saldivar, Sergio O

2011-02-01

The efficiency of ethanol fermentation, as affected by grain source (maize and decorticated red sorghum), total sugar concentration (13 or 20° Plato) and type of microorganism (Saccharomyces cerevisiae or Zymomonas mobilis) was studied. Maize mashes yielded 0.32 l ethanol kg(-1) ground grain whereas mashes prepared with decorticated red sorghum produced 0.28 l ethanol kg(-1). Both microorganisms yielded similar amounts of ethanol. However, high-gravity mashes (20° Plato) yielded lower amounts of ethanol compared to counterparts adjusted to 13° Plato (0.28 vs. 0.22 l ethanol kg(-1) ground grains). In decorticated sorghum mashes adjusted to 20° P, Z. mobilis produced 40 ml kg(-1) more ethanol compared to S. cerevisiae. In addition, Z. mobilis had a lower dependency on nitrogenous compounds.

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)

Understanding the reductions in US corn ethanol production costs: an experience curve approach

USDA-ARS?s Scientific Manuscript database

The US is currently the world's largest ethanol producer. An increasing percentage is used as transportation fuel, but debates continue on its cost competitiveness and energy balance. In this study, technological development of ethanol production and resulting cost reductions are investigated by usi...

High-repetition-rate, narrow-band dye lasers with water as a solvent for dyes

NASA Astrophysics Data System (ADS)

Ray, Alok K.; Sinha, Sucharita; Kundu, Soumitra; Kumar, Sasi; Nair, Sivagiriyal Karunakaran Sreenivasan; Pal, Tamal; Dasgupta, Kamalesh

2002-03-01

The performance of a copper vapor laser-pumped narrow-band dye laser in oscillator-amplifier configuration with water-based binary mixture solvents is described. Although oscillator efficiency in water-surfactant (sodium lauryl sulfate) solvent was comparable with that that employed pure ethanolic solvent, amplifier efficiency was found to be lower. Experiments that were carried out with vertically polarized pump beams and either horizontally or vertically polarized signal beams show that, in case of both the pump and signal having orthogonal polarization (horizontal) and same polarization (vertical), the extraction efficiency for both ethanolic and water-micelle media increased substantially from 15.7% to 18.5% and from 10% to 12.5%, respectively. However, the relative difference remained nearly the same, indicating that a slower orientational diffusion of excited dye molecules in a micellar medium is not responsible for a decrease in amplifier efficiency. Amplifier efficiency comparable with that containing ethanolic dye solutions could be obtained with a binary solvent that comprises a mixture of water and about 30% n-propanol. The performances of two efficient dyes, Rhodamine-6G and Kiton Red S, using water-based solvents were studied.

Energy-Efficient Bioalcohol Recovery by Gel Stripping

NASA Astrophysics Data System (ADS)

Godbole, Rutvik; Ma, Lan; Hedden, Ronald

2014-03-01

Design of energy-efficient processes for recovering butanol and ethanol from dilute fermentations is a key challenge facing the biofuels industry due to the high energy consumption of traditional multi-stage distillation processes. Gel stripping is an alternative purification process by which a dilute alcohol is stripped from the fermentation product by passing it through a packed bed containing particles of a selectively absorbent polymeric gel material. The gel must be selective for the alcohol, while swelling to a reasonable degree in dilute alcohol-water mixtures. To accelerate materials optimization, a combinatorial approach is taken to screen a matrix of copolymer gels having orthogonal gradients in crosslinker concentration and hydrophilicity. Using a combination of swelling in pure solvents, the selectivity and distribution coefficients of alcohols in the gels can be predicted based upon multi-component extensions of Flory-Rehner theory. Predictions can be validated by measuring swelling in water/alcohol mixtures and conducting h HPLC analysis of the external liquid. 95% + removal of butanol from dilute aqueous solutions has been demonstrated, and a mathematical model of the unsteady-state gel stripping process has been developed. NSF CMMI Award 1335082.

Ethanol Production from Various Sugars and Cellulosic Biomass by White Rot Fungus Lenzites betulinus.

PubMed

Im, Kyung Hoan; Nguyen, Trung Kien; Choi, Jaehyuk; Lee, Tae Soo

2016-03-01

Lenzites betulinus, known as gilled polypore belongs to Basidiomycota was isolated from fruiting body on broadleaf dead trees. It was found that the mycelia of white rot fungus Lenzites betulinus IUM 5468 produced ethanol from various sugars, including glucose, mannose, galactose, and cellobiose with a yield of 0.38, 0.26, 0.07, and 0.26 g of ethanol per gram of sugar consumed, respectively. This fungus relatively exhibited a good ethanol production from xylose at 0.26 g of ethanol per gram of sugar consumed. However, the ethanol conversion rate of arabinose was relatively low (at 0.07 g of ethanol per gram sugar). L. betulinus was capable of producing ethanol directly from rice straw and corn stalks at 0.22 g and 0.16 g of ethanol per gram of substrates, respectively, when this fungus was cultured in a basal medium containing 20 g/L rice straw or corn stalks. These results indicate that L. betulinus can produce ethanol efficiently from glucose, mannose, and cellobiose and produce ethanol very poorly from galactose and arabinose. Therefore, it is suggested that this fungus can ferment ethanol from various sugars and hydrolyze cellulosic materials to sugars and convert them to ethanol simultaneously.

Performance of a passive direct ethanol fuel cell

NASA Astrophysics Data System (ADS)

Pereira, J. P.; Falcão, D. S.; Oliveira, V. B.; Pinto, A. M. F. R.

2014-06-01

Ethanol emerges as an attractive fuel since it is less toxic and has higher energy density than methanol and can be produced from biomass. Direct ethanol fuel cells (DEFCs) appear as a good choice for producing sustainable energy for portable applications. However, they are still far from attaining acceptable levels of power output, since their performance is affected by the slow electrochemical ethanol oxidation and water and ethanol crossover. In the present work, an experimental study on the performance of a passive DEFC is described. Tailored MEAs (membrane electrode assembly) with different catalyst loadings, anode diffusion layers and membranes were tested in order to select optimal working conditions at high ethanol concentrations and low ethanol crossover. The performance increased with an increase of membrane and anode diffusion layer thicknesses and anode catalyst loading. A maximum power density of 1.33 mW cm-2, was obtained using a Nafion 117 membrane, 4 mg cm-2 of Pt-Ru and 2 mg cm-2 of Pt on the anode and cathode catalyst layers, ELAT as anode diffusion layer, carbon cloth as cathode diffusion layer and an ethanol concentration of 2 M. As far as the authors are aware this is the first work reporting an experimental optimization of passive DEFCs.

ECUT: Energy Conversion and Utilization Technologies program biocatalysis research activity. Potential membrane applications to biocatalyzed processes: Assessment of concentration polarization and membrane fouling

NASA Technical Reports Server (NTRS)

Ingham, J. D.

1983-01-01

Separation and purification of the products of biocatalyzed fermentation processes, such as ethanol or butanol, consumes most of the process energy required. Since membrane systems require substantially less energy for separation than most alternatives (e.g., distillation) they have been suggested for separation or concentration of fermentation products. This report is a review of the effects of concentration polarization and membrane fouling for the principal membrane processes: microfiltration, ultrafiltration, reverse osmosis, and electrodialysis including a discussion of potential problems relevant to separation of fermentation products. It was concluded that advanced membrane systems may result in significantly decreased energy consumption. However, because of the need to separate large amounts of water from much smaller amounts of product that may be more volatile than wate, it is not clear that membrane separations will necessarily be more efficient than alternative processes.

Papaya drying and waste conversion system. Final report

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

Not Available

1982-02-12

This project, performed under United States Department of Energy Small-scale Appropriate Energy Technology Grant, involves demonstration of an integrated system using solar energy to process off-grade or reject fruit into marketable food products. The integrated system consists of three phases: (1) solar dehydration of usable fruit; (2) solar vacuum distillation of fermented wastes (peelings, rinds, skins, and seeds) to produce an ethanol fuel to use as a backup source of heat for dehydration; and (3) land reclamation by mixing stillage and compost with volcanic cinder and ash to produce on marginal land a rich soil suitable for growing more cropsmore » to dry. Although the system is not 100% complete the investigators have demonstrated that a small business can efficiently use solar energies in an integrated fashion to process waste into food, improve the quality of the land, and provide meaningful jobs in a region of very high unemployment.« less

Modifying Yeast Tolerance to Inhibitory Conditions of Ethanol Production Processes

PubMed Central

Caspeta, Luis; Castillo, Tania; Nielsen, Jens

2015-01-01

Saccharomyces cerevisiae strains having a broad range of substrate utilization, rapid substrate consumption, and conversion to ethanol, as well as good tolerance to inhibitory conditions are ideal for cost-competitive ethanol production from lignocellulose. A major drawback to directly design S. cerevisiae tolerance to inhibitory conditions of lignocellulosic ethanol production processes is the lack of knowledge about basic aspects of its cellular signaling network in response to stress. Here, we highlight the inhibitory conditions found in ethanol production processes, the targeted cellular functions, the key contributions of integrated -omics analysis to reveal cellular stress responses according to these inhibitors, and current status on design-based engineering of tolerant and efficient S. cerevisiae strains for ethanol production from lignocellulose. PMID:26618154

Biofuel vs. Biodiversity? Integrated Emergy and Economic Cost-Benefit Evaluation of Rice-Ethanol Production in Japan

EPA Science Inventory

Energy analysis results confirmed that abandoned rice fields provide a good opportunity for Japan to fulfill its E-3 target by producing ethanol from high-yield rice feedstock. However, to be a viable alternative, a biofuel should not only provide a net energy gain and reduce the...

Two-step size reduction and post-washing of steam exploded corn stover improving simultaneous saccharification and fermentation for ethanol production.

PubMed

Liu, Zhi-Hua; Chen, Hong-Zhang

2017-01-01

The simultaneous saccharification and fermentation (SSF) of corn stover biomass for ethanol production was performed by integrating steam explosion (SE) pretreatment, hydrolysis and fermentation. Higher SE pretreatment severity and two-step size reduction increased the specific surface area, swollen volume and water holding capacity of steam exploded corn stover (SECS) and hence facilitated the efficiency of hydrolysis and fermentation. The ethanol production and yield in SSF increased with the decrease of particle size and post-washing of SECS prior to fermentation to remove the inhibitors. Under the SE conditions of 1.5MPa and 9min using 2.0cm particle size, glucan recovery and conversion to glucose by enzymes were 86.2% and 87.2%, respectively. The ethanol concentration and yield were 45.0g/L and 85.6%, respectively. With this two-step size reduction and post-washing strategy, the water utilization efficiency, sugar recovery and conversion, and ethanol concentration and yield by the SSF process were improved. Copyright © 2016 Elsevier Ltd. All rights reserved.

Continuous energy recovery and nutrients removal from molasses wastewater by synergistic system of dark fermentation and algal culture under various fermentation types.

PubMed

Ren, Hong-Yu; Kong, Fanying; Ma, Jun; Zhao, Lei; Xie, Guo-Jun; Xing, Defeng; Guo, Wan-Qian; Liu, Bing-Feng; Ren, Nan-Qi

2018-03-01

Synergistic system of dark fermentation and algal culture was initially operated at batch mode to investigate the energy production and nutrients removal from molasses wastewater in butyrate-type, ethanol-type and propionate-type fermentations. Butyrate-type fermentation was the most appropriate fermentation type for the synergistic system and exhibited the accumulative hydrogen volume of 658.3 mL L -1 and hydrogen yield of 131.7 mL g -1 COD. By-products from dark fermentation (mainly acetate and butyrate) were further used to cultivate oleaginous microalgae. The maximum algal biomass and lipid content reached 1.01 g L -1 and 38.5%, respectively. In continuous operation, the synergistic system was stable and efficient, and energy production increased from 8.77 kJ L -1  d -1 (dark fermentation) to 17.3 kJ L -1  d -1 (synergistic system). Total COD, TN and TP removal efficiencies in the synergistic system reached 91.1%, 89.1% and 85.7%, respectively. This study shows the potential of the synergistic system in energy recovery and wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Center for Advanced Biofuel Systems (CABS) Final Report

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

Kutchan, Toni M.

2015-12-02

One of the great challenges facing current and future generations is how to meet growing energy demands in an environmentally sustainable manner. Renewable energy sources, including wind, geothermal, solar, hydroelectric, and biofuel energy systems, are rapidly being developed as sustainable alternatives to fossil fuels. Biofuels are particularly attractive to the U.S., given its vast agricultural resources. The first generation of biofuel systems was based on fermentation of sugars to produce ethanol, typically from food crops. Subsequent generations of biofuel systems, including those included in the CABS project, will build upon the experiences learned from those early research results and willmore » have improved production efficiencies, reduced environmental impacts and decreased reliance on food crops. Thermodynamic models predict that the next generations of biofuel systems will yield three- to five-fold more recoverable energy products. To address the technological challenges necessary to develop enhanced biofuel systems, greater understanding of the non-equilibrium processes involved in solar energy conversion and the channeling of reduced carbon into biofuel products must be developed. The objective of the proposed Center for Advanced Biofuel Systems (CABS) was to increase the thermodynamic and kinetic efficiency of select plant- and algal-based fuel production systems using rational metabolic engineering approaches grounded in modern systems biology. The overall strategy was to increase the efficiency of solar energy conversion into oils and other specialty biofuel components by channeling metabolic flux toward products using advanced catalysts and sensible design:1) employing novel protein catalysts that increase the thermodynamic and kinetic efficiencies of photosynthesis and oil biosynthesis; 2) engineering metabolic networks to enhance acetyl-CoA production and its channeling towards lipid synthesis; and 3) engineering new metabolic networks for the production of hydrocarbons required to meet commercial fuel standards.« less

Continuous production of ethanol with Zymomonas mobilis growing on Jerusalem artichoke juice

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

Allais, J.J.; Torres, E.F.; Baratti, J.

1987-04-01

Recent work from the authors laboratory has shown that, compared to yeasts, much higher ethanol productivity and yield can be obtained in batch or continuous cultures using the bacterium Zymomonas mobilis grown on fructose media. In batch culture, hydrolyzed Jerusalem artichoke juice with sugar concentrations ranging from 100 to 250 g/L can be converted efficiently to ethanol. The present work describes the conversion of the hydrolyzed juice to ethanol in continuous culture. The extraction and enzymatic hydrolysis of inulin from the tubers of Jerusalem artichoke is also reported.

Evaporative cooling by a pulsed jet spray of binary ethanol-water mixture

NASA Astrophysics Data System (ADS)

Karpov, P. N.; Nazarov, A. D.; Serov, A. F.; Terekhov, V. I.

2015-07-01

We have experimentally studied the heat transfer under conditions of pulsed multinozzle jet spray impact onto a vertical surface. The working coolant fluid was aqueous ethanol solution in a range of concentrations K 1 = 0-96%. The duration of spray pulses was τ = 2, 4, and 10 ms at a repetition frequency of 10 Hz. The maximum heat transfer coefficient was achieved at an ethanol solution concentration within 50-60%. The thermal efficiency of pulsed spray cooling grows with increasing ethanol concentration and decreasing jet spray pulse duration.

Evaluation on Microalgae Biomass for Bioethanol Production

NASA Astrophysics Data System (ADS)

Chng, L. M.; Lee, K. T.; Chan, D. C. J.

2017-06-01

The depletion of energy resources has triggered worldwide concern for alternative sources, especially renewable energy. Microalgae biomass offers the most promising feedstock for renewable energy because of their impressive efficient growing characteristics and valuable composition. Simple cell structure of the microalgae would simplify the pretreatment technology thus increase the cost-effectiveness of biofuel production. Scenedesmus dimorphus is a carbohydrate-rich microalgae that has potential as biomass for bioethanol. The cultivation of Scenedesmus dimorphus under aeration of carbon dioxide enriched air resulted 1.47 g/L of dry biomass with composition of 12 w/w total lipid, 53.7 w/w carbohydrate and 17.4 protein. Prior to ethanolic fermentation with Saccharomyces cerevisiae, various pre-treatment methods were investigated to release and degrade the complex carbohydrate in cell biomass thus obtaining the maximal amount of digestible sugar for ethanolic yeast. In this study, sulfuric acid was used as hydrolysis agent while amyloglucosidase as enzymatic agent. Dried biomass via hydrothermal acidic hydrolysis yielded sugar which is about 89 of total carbohydrate at reaction temperature of 125 °C and acid concentration of 4 v/v. While combination of organosolv treatment (mixture of methanol and chloroform) with enzymatic hydrolysis yielded comparable amount of sugar with 0.568 g glucose/g treated-biomass. In this study, the significant information in pre-treatment process ensures the sustainability of the biofuel produced.

Speeding up the self-assembly of a DNA nanodevice using a variety of polar solvents.

PubMed

kang, Di; Duan, Ruixue; Tan, Yerpeng; Hong, Fan; Wang, Boya; Chen, Zhifei; Xu, Shaofang; Lou, Xiaoding; Wei, Wei; Yurke, Bernard; Xia, Fan

2014-11-06

The specific recognition and programmable assembly properties make DNA a potential material for nanodevices. However, the more intelligent the nanodevice is, the more complicated the structure of the nanodevice is, which limits the speed of DNA assembly. Herein, to address this problem, we investigate the performance of DNA Strand Displacement Reaction (DSDR) in a mixture of polar organic solvents and aqueous buffer and demonstrate that the organic polar solvent can speed up DNA self-assembly efficiently. Taking DSDR in 20% ethanol as an example, first we have demonstrated that the DSDR is highly accelerated in the beginning of the reaction and it can complete 60% of replacement reactions (160% enhancement compared with aqueous buffer) in the first 300 seconds. Secondly, we calculated that the ΔΔG of the DSDR in 20% ethanol (-18.2 kcal mol(-1)) is lower than that in pure aqueous buffer (-32.6 kcal mol(-1)), while the activation energy is lowered by introducing ethanol. Finally, we proved that the DSDR on the electrode surface can also be accelerated using this simple strategy. More importantly, to test the efficacy of this approach in nanodevices with a complicated and slow DNA self-assembly process, we apply this strategy in the hybridization chain reaction (HCR) and prove the acceleration is fairly obvious in 20% ethanol, which demonstrates the feasibility of the proposed strategy in DNA nanotechnology and DNA-based biosensors.

Production of high concentrated cellulosic ethanol by acetone/water oxidized pretreated beech wood.

PubMed

Katsimpouras, Constantinos; Kalogiannis, Konstantinos G; Kalogianni, Aggeliki; Lappas, Angelos A; Topakas, Evangelos

2017-01-01

Lignocellulosic biomass is an abundant and inexpensive resource for biofuel production. Alongside its biotechnological conversion, pretreatment is essential to enable efficient enzymatic hydrolysis by making cellulose susceptible to cellulases. Wet oxidation of biomass, such as acetone/water oxidation, that employs hot acetone, water, and oxygen, has been found to be an attractive pretreatment method for removing lignin while producing less degradation products. The remaining enriched cellulose fraction has the potential to be utilized under high gravity enzymatic saccharification and fermentation processes for the cost-competing production of bioethanol. Beech wood residual biomass was pretreated following an acetone/water oxidation process aiming at the production of high concentration of cellulosic ethanol. The effect of pressure, reaction time, temperature, and acetone-to-water ratio on the final composition of the pretreated samples was studied for the efficient utilization of the lignocellulosic feedstock. The optimal conditions were acetone/water ratio 1:1, 40 atm initial pressure of 40 vol% O 2 gas, and 64 atm at reaction temperature of 175 °C for 2 h incubation. The pretreated beech wood underwent an optimization step studying the effect of enzyme loading and solids content on the enzymatic liquefaction/saccharification prior to fermentation. In a custom designed free-fall mixer at 50 °C for either 6 or 12 h of prehydrolysis using an enzyme loading of 9 mg/g dry matter at 20 wt% initial solids content, high ethanol concentration of 75.9 g/L was obtained. The optimization of the pretreatment process allowed the efficient utilization of beech wood residual biomass for the production of high concentrations of cellulosic ethanol, while obtaining lignin that can be upgraded towards high-added-value chemicals. The threshold of 4 wt% ethanol concentration that is required for the sustainable bioethanol production was surpassed almost twofold, underpinning the efficient conversion of biomass to ethanol and bio-based chemicals on behalf of the biorefinery concept.

Photoelectrochemical hydrogen production from biomass derivatives and water.

PubMed

Lu, Xihong; Xie, Shilei; Yang, Hao; Tong, Yexiang; Ji, Hongbing

2014-11-21

Hydrogen, a clean energy carrier with high energy capacity, is a very promising candidate as a primary energy source for the future. Photoelectrochemical (PEC) hydrogen production from renewable biomass derivatives and water is one of the most promising approaches to producing green chemical fuel. Compared to water splitting, hydrogen production from renewable biomass derivatives and water through a PEC process is more efficient from the viewpoint of thermodynamics. Additionally, the carbon dioxide formed can be re-transformed into carbohydrates via photosynthesis in plants. In this review, we focus on the development of photoanodes and systems for PEC hydrogen production from water and renewable biomass derivatives, such as methanol, ethanol, glycerol and sugars. We also discuss the future challenges and opportunities for the design of the state-of-the-art photoanodes and PEC systems for hydrogen production from biomass derivatives and water.

Ethanol and thermotolerance in the bioconversion of xylose by yeasts

Treesearch

Thomas W. Jeffries; Yong-Su Jin

2000-01-01

The mechanisms underlying ethanol and heat tolerance are complex. Many different genes are involved, and the exact basis is not fully understood. The integrity of cytoplasmic and mitochondrial membranes is critical to maintain proton gradients for metabolic energy and nutrient uptake. Heat and ethanol stress adversely affect membrane integrity. These factors are...

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

Begley, R.

The ongoing political battle over ethanol's role in federal clean fuels programs is heating up. The Senate passed an energy bill containing additional tax credits for ethanol, and the corn growers lobby last Wednesday called on the Administration to make a decision on the alcohol's place in reformulated gasoline by August 25. In late March, the Environment Protection Agency proposed a Clean Air Act reformulated gasoline oxygenate rule based on earlier negotiations that included the enthanol industry. The industry now says the rule, which is to take effect in 1995 in the nine cities with the worst ozone pollution, wouldmore » restrict gasoline blended with ethanol due to strict volatility requirements. Four powerful senators wrote a letter to EPA Administrator WIlliam K. Reilly protesting ethanol's de facto exclusion from the clean fuels initiative, charging that the Clean Air Act is being used as a methanol mandate at the expense of ethanol'. The energy bill passed by the Senate July 30 includes an amendment by Sen. Tom Daschle (D. SD) to extend the tax exemption enjoyed ten percent by ethanol gasoline blends to lower concentrations.« less

Application of multicriteria decision making methods to compression ignition engine efficiency and gaseous, particulate, and greenhouse gas emissions.

PubMed

Surawski, Nicholas C; Miljevic, Branka; Bodisco, Timothy A; Brown, Richard J; Ristovski, Zoran D; Ayoko, Godwin A

2013-02-19

Compression ignition (CI) engine design is subject to many constraints, which present a multicriteria optimization problem that the engine researcher must solve. In particular, the modern CI engine must not only be efficient but must also deliver low gaseous, particulate, and life cycle greenhouse gas emissions so that its impact on urban air quality, human health, and global warming is minimized. Consequently, this study undertakes a multicriteria analysis, which seeks to identify alternative fuels, injection technologies, and combustion strategies that could potentially satisfy these CI engine design constraints. Three data sets are analyzed with the Preference Ranking Organization Method for Enrichment Evaluations and Geometrical Analysis for Interactive Aid (PROMETHEE-GAIA) algorithm to explore the impact of (1) an ethanol fumigation system, (2) alternative fuels (20% biodiesel and synthetic diesel) and alternative injection technologies (mechanical direct injection and common rail injection), and (3) various biodiesel fuels made from 3 feedstocks (i.e., soy, tallow, and canola) tested at several blend percentages (20-100%) on the resulting emissions and efficiency profile of the various test engines. The results show that moderate ethanol substitutions (~20% by energy) at moderate load, high percentage soy blends (60-100%), and alternative fuels (biodiesel and synthetic diesel) provide an efficiency and emissions profile that yields the most "preferred" solutions to this multicriteria engine design problem. Further research is, however, required to reduce reactive oxygen species (ROS) emissions with alternative fuels and to deliver technologies that do not significantly reduce the median diameter of particle emissions.

Co-fermentation of glucose, xylose and/or cellobiose by yeast

DOEpatents

Jeffries, Thomas W.; Willis, Laura B.; Long, Tanya M.; Su, Yi-Kai

2013-09-10

Provided herein are methods of using yeast cells to produce ethanol by contacting a mixture comprising xylose with a Spathaspora yeast cell under conditions suitable to allow the yeast to ferment at least a portion of the xylose to ethanol. The methods allow for efficient ethanol production from hydrolysates derived from lignocellulosic material and sugar mixtures including at least xylose and glucose or xylose, glucose and cellobiose.

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.

Development of a high-throughput assay for rapid screening of butanologenic strains.

PubMed

Agu, Chidozie Victor; Lai, Stella M; Ujor, Victor; Biswas, Pradip K; Jones, Andy; Gopalan, Venkat; Ezeji, Thaddeus Chukwuemeka

2018-02-21

We report a Thermotoga hypogea (Th) alcohol dehydrogenase (ADH)-dependent spectrophotometric assay for quantifying the amount of butanol in growth media, an advance that will facilitate rapid high-throughput screening of hypo- and hyper-butanol-producing strains of solventogenic Clostridium species. While a colorimetric nitroblue tetrazolium chloride-based assay for quantitating butanol in acetone-butanol-ethanol (ABE) fermentation broth has been described previously, we determined that Saccharomyces cerevisiae (Sc) ADH used in this earlier study exhibits approximately 13-fold lower catalytic efficiency towards butanol than ethanol. Any Sc ADH-dependent assay for primary quantitation of butanol in an ethanol-butanol mixture is therefore subject to "ethanol interference". To circumvent this limitation and better facilitate identification of hyper-butanol-producing Clostridia, we searched the literature for native ADHs that preferentially utilize butanol over ethanol and identified Th ADH as a candidate. Indeed, recombinant Th ADH exhibited a 6-fold higher catalytic efficiency with butanol than ethanol, as measured using the reduction of NADP + to NADPH that accompanies alcohol oxidation. Moreover, the assay sensitivity was not affected by the presence of acetone, acetic acid or butyric acid (typical ABE fermentation products). We broadened the utility of our assay by adapting it to a high-throughput microtiter plate-based format, and piloted it successfully in an ongoing metabolic engineering initiative.

Design and test of a 10kW ORC supersonic turbine generator

NASA Astrophysics Data System (ADS)

Seume, J. R.; Peters, M.; Kunte, H.

2017-03-01

Manufactures are searching for possibilities to increase the efficiency of combustion engines by using the remaining energy of the exhaust gas. One possibility to recover some of this thermal energy is an organic Rankine cycle (ORC). For such an ORC running with ethanol, the aerothermodynamic design and test of a supersonic axial, single stage impulse turbine generator unit is described. The blade design as well as the regulation by variable partial admission is shown. Additionally the mechanical design of the directly coupled turbine generator unit including the aerodynamic sealing and the test facility is presented. Finally the results of CFD-based computations are compared to the experimental measurements. The comparison shows a remarkably good agreement between the numerical computations and the test data.

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.

Field to fuel: developing sustainable biorefineries.

PubMed

Jenkins, Robin; Alles, Carina

2011-06-01

Life-cycle assessment (LCA) can be used as a scientific decision support technique to quantify the environmental implications of various biorefinery process, feedstock, and integration options. The goal of DuPont's integrated corn biorefinery (ICBR) project, a cost-share project with the United States Department of Energy, was to demonstrate the feasibility of a cellulosic ethanol biorefinery concept. DuPont used LCA to guide research and development to the most sustainable cellulosic ethanol biorefinery design in its ICBR project and will continue to apply LCA in support of its ongoing effort with joint venture partners. Cellulosic ethanol is a biofuel which has the potential to provide a sustainable solution to the nation's growing concerns around energy supply and climate change. A successful biorefinery begins with sustainable removal of biomass from the field. Michigan State University (MSU) used LCA to estimate the environmental performance of corn grain, corn stover, and the corn cob portion of the stover, grown under various farming practices for several corn growing locations in the United States Corn Belt. In order to benchmark the future technology options for producing cellulosic ethanol with existing technologies, LCA results for fossil energy consumption and greenhouse gas (GHG) emissions are compared to alternative ethanol processes and conventional gasoline. Preliminary results show that the DuPont ICBR outperforms gasoline and other ethanol technologies in the life-cycle impact categories considered here.

Efficient ethanol recovery from yeast fermentation broth with integrated distillation-membrane process

EPA Science Inventory

A hybrid process integrating vapor stripping with vapor compression and vapor permeation membrane separation, termed Membrane Assisted Vapor Stripping (MAVS), was evaluated for recovery and dehydration of ethanol from aqueous solution as an alternative to conventional distillatio...

Biological caproate production by Clostridium kluyveri from ethanol and acetate as carbon sources.

PubMed

Yin, Yanan; Zhang, Yifeng; Karakashev, Dimitar Borisov; Wang, Jianlong; Angelidaki, Irini

2017-10-01

Caproate is a valuable industrial product and chemical precursor. In this study, batch tests were conducted to investigate the fermentative caproate production through chain elongation from acetate and ethanol. The effect of acetate/ethanol ratio and initial ethanol concentration on caproate production was examined. When substrate concentration was controlled at 100mM total carbon, hydrogen was used as an additional electron donor. The highest caproate concentration of 3.11g/L was obtained at an ethanol/acetate ratio of 7:3. No additional electron donor was needed upon an ethanol/acetate ratio ≥7:3. Caproate production increased with the increase of carbon source until ethanol concentration over 700mM, which inhibited the fermentation process. The highest caproate concentration of 8.42g/L was achieved from high ethanol strength wastewater with an ethanol/acetate ratio of 10:1 (550mM total carbon). Results obtained in this study can pave the way towards efficient chain elongation from ethanol-rich wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Combining inhibitor tolerance and D-xylose fermentation in industrial Saccharomyces cerevisiae for efficient lignocellulose-based bioethanol production.

PubMed

Demeke, Mekonnen M; Dumortier, Françoise; Li, Yingying; Broeckx, Tom; Foulquié-Moreno, María R; Thevelein, Johan M

2013-08-26

In addition to efficient pentose utilization, high inhibitor tolerance is a key trait required in any organism used for economically viable industrial bioethanol production with lignocellulose biomass. Although recent work has succeeded in establishing efficient xylose fermentation in robust industrial Saccharomyces cerevisiae strains, the resulting strains still lacked sufficient inhibitor tolerance for efficient sugar fermentation in lignocellulose hydrolysates. The aim of the present work was to combine high xylose fermentation activity and high inhibitor tolerance in a single industrial yeast strain. We have screened 580 yeast strains for high inhibitor tolerance using undetoxified acid-pretreated spruce hydrolysate and identified a triploid industrial baker's yeast strain as having the highest inhibitor tolerance. From this strain, a mating competent diploid segregant with even higher inhibitor tolerance was obtained. It was crossed with the recently developed D-xylose fermenting diploid industrial strain GS1.11-26, with the Ethanol Red genetic background. Screening of 819 diploid segregants from the tetraploid hybrid resulted in two strains, GSF335 and GSF767, combining high inhibitor tolerance and efficient xylose fermentation. In a parallel approach, meiotic recombination of GS1.11-26 with a haploid segregant of Ethanol Red and screening of 104 segregants resulted in a similar inhibitor tolerant diploid strain, GSE16. The three superior strains exhibited significantly improved tolerance to inhibitors in spruce hydrolysate, higher glucose consumption rates, higher aerobic growth rates and higher maximal ethanol accumulation capacity in very-high gravity fermentation, compared to GS1.11-26. In complex medium, the D-xylose utilization rate by the three superior strains ranged from 0.36 to 0.67 g/g DW/h, which was lower than that of GS1.11-26 (1.10 g/g DW/h). On the other hand, in batch fermentation of undetoxified acid-pretreated spruce hydrolysate, the three superior strains showed comparable D-xylose utilization rates as GS1.11-26, probably because of their higher inhibitor tolerance. They produced up to 23% more ethanol compared to Ethanol Red. We have successfully constructed three superior industrial S. cerevisiae strains that combine efficient D-xylose utilization with high inhibitor tolerance. Since the background strain Ethanol Red has a proven record of successful industrial application, the three new superior strains have strong potential for direct application in industrial bioethanol production.

Combining inhibitor tolerance and D-xylose fermentation in industrial Saccharomyces cerevisiae for efficient lignocellulose-based bioethanol production

PubMed Central

2013-01-01

Background In addition to efficient pentose utilization, high inhibitor tolerance is a key trait required in any organism used for economically viable industrial bioethanol production with lignocellulose biomass. Although recent work has succeeded in establishing efficient xylose fermentation in robust industrial Saccharomyces cerevisiae strains, the resulting strains still lacked sufficient inhibitor tolerance for efficient sugar fermentation in lignocellulose hydrolysates. The aim of the present work was to combine high xylose fermentation activity and high inhibitor tolerance in a single industrial yeast strain. Results We have screened 580 yeast strains for high inhibitor tolerance using undetoxified acid-pretreated spruce hydrolysate and identified a triploid industrial baker’s yeast strain as having the highest inhibitor tolerance. From this strain, a mating competent diploid segregant with even higher inhibitor tolerance was obtained. It was crossed with the recently developed D-xylose fermenting diploid industrial strain GS1.11-26, with the Ethanol Red genetic background. Screening of 819 diploid segregants from the tetraploid hybrid resulted in two strains, GSF335 and GSF767, combining high inhibitor tolerance and efficient xylose fermentation. In a parallel approach, meiotic recombination of GS1.11-26 with a haploid segregant of Ethanol Red and screening of 104 segregants resulted in a similar inhibitor tolerant diploid strain, GSE16. The three superior strains exhibited significantly improved tolerance to inhibitors in spruce hydrolysate, higher glucose consumption rates, higher aerobic growth rates and higher maximal ethanol accumulation capacity in very-high gravity fermentation, compared to GS1.11-26. In complex medium, the D-xylose utilization rate by the three superior strains ranged from 0.36 to 0.67 g/g DW/h, which was lower than that of GS1.11-26 (1.10 g/g DW/h). On the other hand, in batch fermentation of undetoxified acid-pretreated spruce hydrolysate, the three superior strains showed comparable D-xylose utilization rates as GS1.11-26, probably because of their higher inhibitor tolerance. They produced up to 23% more ethanol compared to Ethanol Red. Conclusions We have successfully constructed three superior industrial S. cerevisiae strains that combine efficient D-xylose utilization with high inhibitor tolerance. Since the background strain Ethanol Red has a proven record of successful industrial application, the three new superior strains have strong potential for direct application in industrial bioethanol production. PMID:23971950

Structural transformations, composition anomalies and a dramatic collapse of linear polymer chains in dilute ethanol-water mixtures.

PubMed

Banerjee, Saikat; Ghosh, Rikhia; Bagchi, Biman

2012-03-29

Water-ethanol mixtures exhibit many interesting anomalies, such as negative excess partial molar volume of ethanol, excess sound absorption coefficient at low concentrations, and positive deviation from Raoult's law for vapor pressure, to mention a few. These anomalies have been attributed to different, often contradictory origins, but a quantitative understanding is still lacking. We show by computer simulation and theoretical analyses that these anomalies arise from the sudden emergence of a bicontinuous phase that occurs at a relatively low ethanol concentration of x(eth) ≈ 0.06-0.10 (that amounts to a volume fraction of 0.17-0.26, which is a significant range!). The bicontinuous phase is formed by aggregation of ethanol molecules, resulting in a weak phase transition whose nature is elucidated. We find that the microheterogeneous structure of the mixture gives rise to a pronounced nonmonotonic composition dependence of local compressibility and nonmonotonic dependence in the peak value of the radial distribution function of ethyl groups. A multidimensional free energy surface of pair association is shown to provide a molecular explanation of the known negative excess partial volume of ethanol in terms of parallel orientation and hence better packing of the ethyl groups in the mixture due to hydrophobic interactions. The energy distribution of the ethanol molecules indicates additional energy decay channels that explain the excess sound attenuation coefficient in aqueous alcohol mixtures. We studied the dependence of the solvation of a linear polymer chain on the composition of the water-ethanol solvent. We find that there is a sudden collapse of the polymer at x(eth) ≈ 0.05-a phenomenon which we attribute to the formation of the microheterogeneous structures in the binary mixture at low ethanol concentrations. Together with recent single molecule pulling experiments, these results provide new insight into the behavior of polymer chain and foreign solutes, such as enzymes, in aqueous binary mixtures.

Renewable energy for an environmentally sustainable energy future

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

Sunderman, D.N.

1993-12-31

One of the major objectives of the renewable energy program is to allow the employment of environmentally benign energy technologies based upon the sun. Other objectives include national energy independence and industrial competitiveness in future energy technology markets. The National Renewable Energy Laboratory (formerly SERI) in Golden, Colorado, has for 15 years been the lead U.S. laboratory in research on photovoltaics, wind energy systems, and ethanol from biomass. During this period, substantional cost reductions were achieved and efficiencies improved. NREL also works closely with industry to facilitate the commercialization of these and related technologies. As much as 50% of NRELmore » funding goes to industry in cost-shared contracts for research and development, planned with industry representatives and the U.S. Department of Energy. Besides lessening dependence on fossil fuels and their short-term environmental impacts, these technologies will also alleviate the impact on the potential global warming issue. Other direct environmental research at NREL is the solar-detox program, in which solar radiation is employed to destroy hazardous organic materials in ground water and other waste streams.« less

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.

Fuel ethanol production: process design trends and integration opportunities.

PubMed

Cardona, Carlos A; Sánchez, Oscar J

2007-09-01

Current fuel ethanol research and development deals with process engineering trends for improving biotechnological production of ethanol. In this work, the key role that process design plays during the development of cost-effective technologies is recognized through the analysis of major trends in process synthesis, modeling, simulation and optimization related to ethanol production. Main directions in techno-economical evaluation of fuel ethanol processes are described as well as some prospecting configurations. The most promising alternatives for compensating ethanol production costs by the generation of valuable co-products are analyzed. Opportunities for integration of fuel ethanol production processes and their implications are underlined. Main ways of process intensification through reaction-reaction, reaction-separation and separation-separation processes are analyzed in the case of bioethanol production. Some examples of energy integration during ethanol production are also highlighted. Finally, some concluding considerations on current and future research tendencies in fuel ethanol production regarding process design and integration are presented.

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.

Ethanol Production from Various Sugars and Cellulosic Biomass by White Rot Fungus Lenzites betulinus

PubMed Central

Im, Kyung Hoan; Nguyen, Trung Kien; Choi, Jaehyuk

2016-01-01

Lenzites betulinus, known as gilled polypore belongs to Basidiomycota was isolated from fruiting body on broadleaf dead trees. It was found that the mycelia of white rot fungus Lenzites betulinus IUM 5468 produced ethanol from various sugars, including glucose, mannose, galactose, and cellobiose with a yield of 0.38, 0.26, 0.07, and 0.26 g of ethanol per gram of sugar consumed, respectively. This fungus relatively exhibited a good ethanol production from xylose at 0.26 g of ethanol per gram of sugar consumed. However, the ethanol conversion rate of arabinose was relatively low (at 0.07 g of ethanol per gram sugar). L. betulinus was capable of producing ethanol directly from rice straw and corn stalks at 0.22 g and 0.16 g of ethanol per gram of substrates, respectively, when this fungus was cultured in a basal medium containing 20 g/L rice straw or corn stalks. These results indicate that L. betulinus can produce ethanol efficiently from glucose, mannose, and cellobiose and produce ethanol very poorly from galactose and arabinose. Therefore, it is suggested that this fungus can ferment ethanol from various sugars and hydrolyze cellulosic materials to sugars and convert them to ethanol simultaneously. PMID:27103854

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.

Influence of corn oil recovery on life-cycle greenhouse gas emissions of corn ethanol and corn oil biodiesel

DOE PAGES

Wang, Zhichao; Dunn, Jennifer B.; Han, Jeongwoo; ...

2015-11-04

Corn oil recovery and conversion to biodiesel has been widely adopted at corn ethanol plants recently. The US EPA has projected 2.6 billion liters of biodiesel will be produced from corn oil in 2022. Corn oil biodiesel may qualify for federal renewable identification number (RIN) credits under the Renewable Fuel Standard, as well as for low greenhouse gas (GHG) emission intensity credits under California’s Low Carbon Fuel Standard. Because multiple products [ethanol, biodiesel, and distiller’s grain with solubles (DGS)] are produced from one feedstock (corn), however, a careful co-product treatment approach is required to accurately estimate GHG intensities of bothmore » ethanol and corn oil biodiesel and to avoid double counting of benefits associated with corn oil biodiesel production. This study develops four co-product treatment methods: (1) displacement, (2) marginal, (3) hybrid allocation, and (4) process-level energy allocation. Life-cycle GHG emissions for corn oil biodiesel were more sensitive to the choice of co-product allocation method because significantly less corn oil biodiesel is produced than corn ethanol at a dry mill. Corn ethanol life-cycle GHG emissions with the displacement, marginal, and hybrid allocation approaches are similar (61, 62, and 59 g CO 2e/MJ, respectively). Although corn ethanol and DGS share upstream farming and conversion burdens in both the hybrid and process-level energy allocation methods, DGS bears a higher burden in the latter because it has lower energy content per selling price as compared to corn ethanol. As a result, with the process-level allocation approach, ethanol’s life-cycle GHG emissions are lower at 46 g CO 2e/MJ. Corn oil biodiesel life-cycle GHG emissions from the marginal, hybrid allocation, and process-level energy allocation methods were 14, 59, and 45 g CO 2e/MJ, respectively. Sensitivity analyses were conducted to investigate the influence corn oil yield, soy biodiesel, and defatted DGS displacement credits, and energy consumption for corn oil production and corn oil biodiesel production. Furthermore, this study’s results demonstrate that co-product treatment methodology strongly influences corn oil biodiesel life-cycle GHG emissions and can affect how this fuel is treated under the Renewable Fuel and Low Carbon Fuel Standards.« less

Influence of corn oil recovery on life-cycle greenhouse gas emissions of corn ethanol and corn oil biodiesel

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

Wang, Zhichao; Dunn, Jennifer B.; Han, Jeongwoo

Corn oil recovery and conversion to biodiesel has been widely adopted at corn ethanol plants recently. The US EPA has projected 2.6 billion liters of biodiesel will be produced from corn oil in 2022. Corn oil biodiesel may qualify for federal renewable identification number (RIN) credits under the Renewable Fuel Standard, as well as for low greenhouse gas (GHG) emission intensity credits under California’s Low Carbon Fuel Standard. Because multiple products [ethanol, biodiesel, and distiller’s grain with solubles (DGS)] are produced from one feedstock (corn), however, a careful co-product treatment approach is required to accurately estimate GHG intensities of bothmore » ethanol and corn oil biodiesel and to avoid double counting of benefits associated with corn oil biodiesel production. This study develops four co-product treatment methods: (1) displacement, (2) marginal, (3) hybrid allocation, and (4) process-level energy allocation. Life-cycle GHG emissions for corn oil biodiesel were more sensitive to the choice of co-product allocation method because significantly less corn oil biodiesel is produced than corn ethanol at a dry mill. Corn ethanol life-cycle GHG emissions with the displacement, marginal, and hybrid allocation approaches are similar (61, 62, and 59 g CO 2e/MJ, respectively). Although corn ethanol and DGS share upstream farming and conversion burdens in both the hybrid and process-level energy allocation methods, DGS bears a higher burden in the latter because it has lower energy content per selling price as compared to corn ethanol. As a result, with the process-level allocation approach, ethanol’s life-cycle GHG emissions are lower at 46 g CO 2e/MJ. Corn oil biodiesel life-cycle GHG emissions from the marginal, hybrid allocation, and process-level energy allocation methods were 14, 59, and 45 g CO 2e/MJ, respectively. Sensitivity analyses were conducted to investigate the influence corn oil yield, soy biodiesel, and defatted DGS displacement credits, and energy consumption for corn oil production and corn oil biodiesel production. Furthermore, this study’s results demonstrate that co-product treatment methodology strongly influences corn oil biodiesel life-cycle GHG emissions and can affect how this fuel is treated under the Renewable Fuel and Low Carbon Fuel Standards.« less

Life cycle assessment of switchgrass- and corn stover-derived ethanol-fueled automobiles.

PubMed

Spatari, Sabrina; Zhang, Yimin; MacLean, Heather L

2005-12-15

Utilizing domestically produced cellulose-derived ethanol for the light-duty vehicle fleet can potentially improve the environmental performance and sustainability of the transport and energy sectors of the economy. A life cycle assessment model was developed to examine environmental implications of the production and use of ethanol in automobiles in Ontario, Canada. The results were compared to those of low-sulfur reformulated gasoline (RFG) in a functionally equivalent automobile. Two time frames were evaluated, one near-term (2010), which examines converting a dedicated energy crop (switchgrass) and an agricultural residue (corn stover) to ethanol; and one midterm (2020), which assumes technological improvements in the switchgrass-derived ethanol life cycle. Near-term results show that, compared to a RFG automobile, life cycle greenhouse gas (GHG) emissions are 57% lower for an E85-fueled automobile derived from switchgrass and 65% lower for ethanol from corn stover, on a grams of CO2 equivalent per kilometer basis. Corn stover ethanol exhibits slightly lower life cycle GHG emissions, primarily due to sharing emissions with grain production. Through projected improvements in crop and ethanol yields, results for the mid-term scenario show that GHG emissions could be 25-35% lower than those in 2010 and that, even with anticipated improvements in RFG automobiles, E85 automobiles could still achieve up to 70% lower GHG emissions across the life cycle.

Green analytical method development for statin analysis.

PubMed

Assassi, Amira Louiza; Roy, Claude-Eric; Perovitch, Philippe; Auzerie, Jack; Hamon, Tiphaine; Gaudin, Karen

2015-02-06

Green analytical chemistry method was developed for pravastatin, fluvastatin and atorvastatin analysis. HPLC/DAD method using ethanol-based mobile phase with octadecyl-grafted silica with various grafting and related-column parameters such as particle sizes, core-shell and monolith was studied. Retention, efficiency and detector linearity were optimized. Even for column with particle size under 2 μm, the benefit of keeping efficiency within a large range of flow rate was not obtained with ethanol based mobile phase compared to acetonitrile one. Therefore the strategy to shorten analysis by increasing the flow rate induced decrease of efficiency with ethanol based mobile phase. An ODS-AQ YMC column, 50 mm × 4.6 mm, 3 μm was selected which showed the best compromise between analysis time, statin separation, and efficiency. HPLC conditions were at 1 mL/min, ethanol/formic acid (pH 2.5, 25 mM) (50:50, v/v) and thermostated at 40°C. To reduce solvent consumption for sample preparation, 0.5mg/mL concentration of each statin was found the highest which respected detector linearity. These conditions were validated for each statin for content determination in high concentrated hydro-alcoholic solutions. Solubility higher than 100mg/mL was found for pravastatin and fluvastatin, whereas for atorvastatin calcium salt the maximum concentration was 2mg/mL for hydro-alcoholic binary mixtures between 35% and 55% of ethanol in water. Using atorvastatin instead of its calcium salt, solubility was improved. Highly concentrated solution of statins offered potential fluid for per Buccal Per-Mucous(®) administration with the advantages of rapid and easy passage of drugs. Copyright © 2014 Elsevier B.V. All rights reserved.

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.

A novel sputtered Pd mesh architecture as an advanced electrocatalyst for highly efficient hydrogen production

NASA Astrophysics Data System (ADS)

de Lucas-Consuegra, Antonio; de la Osa, Ana R.; Calcerrada, Ana B.; Linares, José J.; Horwat, David

2016-07-01

This study reports the preparation, characterization and testing of a sputtered Pd mesh-like anode as an advanced electrocatalyst for H2 production from alkaline ethanol solutions in an Alkaline Membrane Electrolyzer (AEM). Pd anodic catalyst is prepared by magnetron sputtering technique onto a microfiber carbon paper support. Scanning Electron Microscopy images reveal that the used preparation technique enables to cover the surface of the carbon microfibers exposed to the Pd target, leading to a continuous network that also maintains part of the original carbon paper macroporosity. Such novel anodic architecture (organic binder free) presents an excellent electro-chemical performance, with a maximum current density of 700 mA cm-2 at 1.3 V, and, concomitantly, a large H2 production rate with low energy requirement compared to water electrolysis. Potassium hydroxide emerges as the best electrolyte, whereas temperature exerts the expected promotional effect up to 90 °C. On the other hand, a 1 mol L-1 ethanol solution is enough to guarantee an efficient fuel supply without any mass transfer limitation. The proposed system also demonstrates to remain stable over 150 h of operation along five consecutives cycles, producing highly pure H2 (99.999%) at the cathode and potassium acetate as the main anodic product.

Bioethanol potentials of corn cob hydrolysed using cellulases of Aspergillus niger and Penicillium decumbens.

PubMed

Saliu, Bolanle Kudirat; Sani, Alhassan

2012-01-01

Corn cob is a major component of agricultural and domestic waste in many parts of the world. It is composed mainly of cellulose which can be converted to energy in form of bioethanol as an efficient and effective means of waste management. Production of cellulolytic enzymes were induced in the fungi Aspergillus niger and Penicillium decumbens by growing them in mineral salt medium containing alkali pre-treated and untreated corn cobs. The cellulases were characterized and partially purified. Alkali pre-treated corn cobs were hydrolysed with the partially purified cellulases and the product of hydrolysis was fermented using the yeast saccharomyces cerevisae to ethanol. Cellulases of A. niger produced higher endoglucanase and exoglucanase activity (0.1698 IU ml(-1) and 0.0461 FPU ml(-1)) compared to that produced by P. decumbens (0.1111 IU ml(-1) and 0.153 FPU ml(-1)). Alkali pre-treated corn cob hydrolysed by cellulases of A. niger yielded 7.63 mg ml(-1) sugar which produced 2.67 % (v/v) ethanol on fermentation. Ethanol yield of the hydrolysates of corn cob by cellulases of P. decumbens was much lower at 0.56 % (v/v). Alkali pre-treated corn cob, hydrolysed with cellulases of A. niger is established as suitable feedstock for bioethanol production.

A Direct Grain-Boundary-Activity Correlation for CO Electroreduction on Cu Nanoparticles

PubMed Central

2016-01-01

Copper catalyzes the electrochemical reduction of CO to valuable C2+ products including ethanol, acetate, propanol, and ethylene. These reactions could be very useful for converting renewable energy into fuels and chemicals, but conventional Cu electrodes are energetically inefficient and have poor selectivity for CO vs H2O reduction. Efforts to design improved catalysts have been impeded by the lack of experimentally validated, quantitative structure–activity relationships. Here we show that CO reduction activity is directly correlated to the density of grain boundaries (GBs) in Cu nanoparticles (NPs). We prepared electrodes of Cu NPs on carbon nanotubes (Cu/CNT) with different average GB densities quantified by transmission electron microscopy. At potentials ranging from −0.3 V to −0.5 V vs the reversible hydrogen electrode, the specific activity for CO reduction to ethanol and acetate was linearly proportional to the fraction of NP surfaces comprised of GB surface terminations. Our results provide a design principle for CO reduction to ethanol and acetate on Cu. GB-rich Cu/CNT electrodes are the first NP catalysts with significant CO reduction activity at moderate overpotential, reaching a mass activity of up to ∼1.5 A per gram of Cu and a Faradaic efficiency >70% at −0.3 V. PMID:27163043

A Direct Grain-Boundary-Activity Correlation for CO Electroreduction on Cu Nanoparticles.

PubMed

Feng, Xiaofeng; Jiang, Kaili; Fan, Shoushan; Kanan, Matthew W

2016-03-23

Copper catalyzes the electrochemical reduction of CO to valuable C2+ products including ethanol, acetate, propanol, and ethylene. These reactions could be very useful for converting renewable energy into fuels and chemicals, but conventional Cu electrodes are energetically inefficient and have poor selectivity for CO vs H2O reduction. Efforts to design improved catalysts have been impeded by the lack of experimentally validated, quantitative structure-activity relationships. Here we show that CO reduction activity is directly correlated to the density of grain boundaries (GBs) in Cu nanoparticles (NPs). We prepared electrodes of Cu NPs on carbon nanotubes (Cu/CNT) with different average GB densities quantified by transmission electron microscopy. At potentials ranging from -0.3 V to -0.5 V vs the reversible hydrogen electrode, the specific activity for CO reduction to ethanol and acetate was linearly proportional to the fraction of NP surfaces comprised of GB surface terminations. Our results provide a design principle for CO reduction to ethanol and acetate on Cu. GB-rich Cu/CNT electrodes are the first NP catalysts with significant CO reduction activity at moderate overpotential, reaching a mass activity of up to ∼1.5 A per gram of Cu and a Faradaic efficiency >70% at -0.3 V.

Pt-Richcore/Sn-Richsubsurface/Ptskin Nanocubes As Highly Active and Stable Electrocatalysts for the Ethanol Oxidation Reaction.

PubMed

Rizo, Rubén; Arán-Ais, Rosa M; Padgett, Elliot; Muller, David A; Lázaro, Ma Jesús; Solla-Gullón, José; Feliu, Juan M; Pastor, Elena; Abruña, Héctor D

2018-03-14

Direct ethanol fuel cells are one of the most promising electrochemical energy conversion devices for portable, mobile and stationary power applications. However, more efficient and stable and less expensive electrocatalysts are still required. Interestingly, the electrochemical performance of the electrocatalysts toward the ethanol oxidation reaction can be remarkably enhanced by exploiting the benefits of structural and compositional sensitivity and control. Here, we describe the synthesis, characterization, and electrochemical behavior of cubic Pt-Sn nanoparticles. The electrochemical activity of the cubic Pt-Sn nanoparticles was found to be about three times higher than that obtained with unshaped Pt-Sn nanoparticles and six times higher than that of Pt nanocubes. In addition, stability tests indicated the electrocatalyst preserves its morphology and remains well-dispersed on the carbon support after 5000 potential cycles, while a cubic (pure) Pt catalyst exhibited severe agglomeration of the nanoparticles after a similar stability testing protocol. A detailed analysis of the elemental distribution in the nanoparticles by STEM-EELS indicated that Sn dissolves from the outer part of the shell after potential cycling, forming a ∼0.5 nm Pt skin. This particular atomic composition profile having a Pt-rich core, a Sn-rich subsurface layer, and a Pt-skin surface structure is responsible for the high activity and stability.

Analysis of the control structures for an integrated ethanol processor for proton exchange membrane fuel cell systems

NASA Astrophysics Data System (ADS)

Biset, S.; Nieto Deglioumini, L.; Basualdo, M.; Garcia, V. M.; Serra, M.

The aim of this work is to investigate which would be a good preliminary plantwide control structure for the process of Hydrogen production from bioethanol to be used in a proton exchange membrane (PEM) accounting only steady-state information. The objective is to keep the process under optimal operation point, that is doing energy integration to achieve the maximum efficiency. Ethanol, produced from renewable feedstocks, feeds a fuel processor investigated for steam reforming, followed by high- and low-temperature shift reactors and preferential oxidation, which are coupled to a polymeric fuel cell. Applying steady-state simulation techniques and using thermodynamic models the performance of the complete system with two different control structures have been evaluated for the most typical perturbations. A sensitivity analysis for the key process variables together with the rigorous operability requirements for the fuel cell are taking into account for defining acceptable plantwide control structure. This is the first work showing an alternative control structure applied to this kind of process.

Techno-economic comparison of centralized versus decentralized biorefineries for two alkaline pretreatment processes.

PubMed

Stoklosa, Ryan J; Del Pilar Orjuela, Andrea; da Costa Sousa, Leonardo; Uppugundla, Nirmal; Williams, Daniel L; Dale, Bruce E; Hodge, David B; Balan, Venkatesh

2017-02-01

In this work, corn stover subjected to ammonia fiber expansion (AFEX™) 1 pretreatment or alkaline pre-extraction followed by hydrogen peroxide post-treatment (AHP pretreatment) were compared for their enzymatic hydrolysis yields over a range of solids loadings, enzymes loadings, and enzyme combinations. Process techno-economic models were compared for cellulosic ethanol production for a biorefinery that handles 2000tons per day of corn stover employing a centralized biorefinery approach with AHP or a de-centralized AFEX pretreatment followed by biomass densification feeding a centralized biorefinery. A techno-economic analysis (TEA) of these scenarios shows that the AFEX process resulted in the highest capital investment but also has the lowest minimum ethanol selling price (MESP) at $2.09/gal, primarily due to good energy integration and an efficient ammonia recovery system. The economics of AHP could be made more competitive if oxidant loadings were reduced and the alkali and sugar losses were also decreased. Copyright © 2016 Elsevier Ltd. All rights reserved.

Improving cost-effectiveness and mitigating risks of renewable energy requirements

NASA Astrophysics Data System (ADS)

Griffin, James P.

Policy makers at the federal and state levels of government are debating actions to reduce U.S. greenhouse gas emissions and dependence on oil as an energy source. Several concerns drive this debate: sharp rises in energy prices, increasing unease about the risks of climate change, energy security, and interest in expanding the domestic renewable energy industry. Renewable energy requirements are frequently proposed to address these concerns, and are currently in place, in various forms, at the federal and state levels of government. These policies specify that a certain portion of the energy supply come from renewable energy sources. This dissertation focuses on a specific proposal, known as 25 X 25, which requires 25% of electricity and motor vehicle transportation fuels supplied to U.S. consumers to come from renewable energy sources, such as wind power and ethanol, by 2025. This dissertation builds on prior energy policy analysis, and more specifically analyses of renewable energy requirements, by assessing the social welfare implications of a 25 x 25 policy and applying new methods of uncertainty analysis to multiple policy options decision makers can use to implement the policy. These methods identify policy options that can improve the cost-effectiveness and reduce the risks of renewable energy requirements. While the dissertation focuses on a specific policy, the research methods and findings are applicable to other renewable energy requirement policies. In the dissertation, I analyze six strategies for implementing a 25 x 25 policy across several hundred scenarios that represent plausible futures for uncertainties in energy markets, such as renewable energy costs, energy demand, and fossil fuel prices. The strategies vary in the availability of resources that qualify towards the policy requirement and the use of a "safety valve" that allows refiners and utilities to pay a constant fee after renewable energy costs reach a predetermined threshold. I test each strategy across the set of scenarios and conclude that an "all-combined" strategy---one that allows greater corn ethanol production and energy efficiency to qualify towards the requirement and includes a safety valve---is the most robust strategy to address future uncertainties in energy markets.

Selective Hydrogenation of CO2 to Ethanol over Cobalt Catalysts.

PubMed

Wang, Lingxiang; Wang, Liang; Zhang, Jian; Liu, Xiaolong; Wang, Hai; Zhang, Wei; Yang, Qi; Ma, Jingyuan; Dong, Xue; Yoo, Seung Jo; Kim, Jin-Gyu; Meng, Xiangju; Xiao, Feng-Shou

2018-05-22

Methods for the hydrogenation of CO 2 into valuable chemicals are in great demand but their development is still challenging. Herein, we report the selective hydrogenation of CO 2 into ethanol over non-noble cobalt catalysts (CoAlO x ), presenting a significant advance for the conversion of CO 2 into ethanol as the major product. By adjusting the composition of the catalysts through the use of different prereduction temperatures, the efficiency of CO 2 to ethanol hydrogenation was optimized; the catalyst reduced at 600 ° gave an ethanol selectivity of 92.1 % at 140 °C with an ethanol time yield of 0.444 mmol g -1  h -1 . Operando FT-IR spectroscopy revealed that the high ethanol selectivity over the CoAlO x catalyst might be due to the formation of acetate from formate by insertion of *CH x , a key intermediate in the production of ethanol by CO 2 hydrogenation. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fermentation of lactose to ethanol in cheese whey permeate and concentrated permeate by engineered Escherichia coli.

PubMed

Pasotti, Lorenzo; Zucca, Susanna; Casanova, Michela; Micoli, Giuseppina; Cusella De Angelis, Maria Gabriella; Magni, Paolo

2017-06-02

Whey permeate is a lactose-rich effluent remaining after protein extraction from milk-resulting cheese whey, an abundant dairy waste. The lactose to ethanol fermentation can complete whey valorization chain by decreasing dairy waste polluting potential, due to its nutritional load, and producing a biofuel from renewable source at the same time. Wild type and engineered microorganisms have been proposed as fermentation biocatalysts. However, they present different drawbacks (e.g., nutritional supplements requirement, high transcriptional demand of recombinant genes, precise oxygen level, and substrate inhibition) which limit the industrial attractiveness of such conversion process. In this work, we aim to engineer a new bacterial biocatalyst, specific for dairy waste fermentation. We metabolically engineered eight Escherichia coli strains via a new expression plasmid with the pyruvate-to-ethanol conversion genes, and we carried out the selection of the best strain among the candidates, in terms of growth in permeate, lactose consumption and ethanol formation. We finally showed that the selected engineered microbe (W strain) is able to efficiently ferment permeate and concentrated permeate, without nutritional supplements, in pH-controlled bioreactor. In the conditions tested in this work, the selected biocatalyst could complete the fermentation of permeate and concentrated permeate in about 50 and 85 h on average, producing up to 17 and 40 g/l of ethanol, respectively. To our knowledge, this is the first report showing efficient ethanol production from the lactose contained in whey permeate with engineered E. coli. The selected strain is amenable to further metabolic optimization and represents an advance towards efficient biofuel production from industrial waste stream.

Manufacturing Ethyl Acetate From Fermentation Ethanol

NASA Technical Reports Server (NTRS)

Rohatgi, Naresh K.; Ingham, John D.

1991-01-01

Conceptual process uses dilute product of fermentation instead of concentrated ethanol. Low-concentration ethanol, extracted by vacuum from fermentation tank, and acetic acid constitutes feedstock for catalytic reaction. Product of reaction goes through steps that increases ethyl acetate content to 93 percent by weight. To conserve energy, heat exchangers recycle waste heat to preheat process streams at various points.

Effects of High Octane Ethanol Blends on Four Legacy Flex-Fuel Vehicles, and a Turbocharged GDI Vehicle

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

Thomas, John F; West, Brian H; Huff, Shean P

The U.S. Department of Energy (DOE) is supporting engine and vehicle research to investigate the potential of high-octane fuels to improve fuel economy. Ethanol has very high research octane number (RON) and heat of vaporization (HoV), properties that make it an excellent spark ignition engine fuel. The prospects of increasing both the ethanol content and the octane number of the gasoline pool has the potential to enable improved fuel economy in future vehicles with downsized, downsped engines. This report describes a small study to explore the potential performance benefits of high octane ethanol blends in the legacy fleet. There aremore » over 17 million flex-fuel vehicles (FFVs) on the road today in the United States, vehicles capable of using any fuel from E0 to E85. If a future high-octane blend for dedicated vehicles is on the horizon, the nation is faced with the classic chicken-and-egg dilemma. If today’s FFVs can see a performance advantage with a high octane ethanol blend such as E25 or E30, then perhaps consumer demand for this fuel can serve as a bridge to future dedicated vehicles. Experiments were performed with four FFVs using a 10% ethanol fuel (E10) with 88 pump octane, and a market gasoline blended with ethanol to make a 30% by volume ethanol fuel (E30) with 94 pump octane. The research octane numbers were 92.4 for the E10 fuel and 100.7 for the E30 fuel. Two vehicles had gasoline direct injected (GDI) engines, and two featured port fuel injection (PFI). Significant wide open throttle (WOT) performance improvements were measured for three of the four FFVs, with one vehicle showing no change. Additionally, a conventional (non-FFV) vehicle with a small turbocharged direct-injected engine was tested with a regular grade of gasoline with no ethanol (E0) and a splash blend of this same fuel with 15% ethanol by volume (E15). RON was increased from 90.7 for the E0 to 97.8 for the E15 blend. Significant wide open throttle and thermal efficiency performance improvement was measured for this vehicle, which achieved near volumetric fuel economy parity on the aggressive US06 drive cycle, demonstrating the potential for improved fuel economy in forthcoming downsized, downsped engines with high-octane fuels.« less

The greenhouse gas emissions performance of cellulosic ethanol supply chains in Europe

PubMed Central

Slade, Raphael; Bauen, Ausilio; Shah, Nilay

2009-01-01

Background Calculating the greenhouse gas savings that may be attributed to biofuels is problematic because production systems are inherently complex and methods used to quantify savings are subjective. Differing approaches and interpretations have fuelled a debate about the environmental merit of biofuels, and consequently about the level of policy support that can be justified. This paper estimates and compares emissions from plausible supply chains for lignocellulosic ethanol production, exemplified using data specific to the UK and Sweden. The common elements that give rise to the greatest greenhouse gas emissions are identified and the sensitivity of total emissions to variations in these elements is estimated. The implications of including consequential impacts including indirect land-use change, and the effects of selecting alternative allocation methods on the interpretation of results are discussed. Results We find that the most important factors affecting supply chain emissions are the emissions embodied in biomass production, the use of electricity in the conversion process and potentially consequential impacts: indirect land-use change and fertiliser replacement. The large quantity of electricity consumed during enzyme manufacture suggests that enzymatic conversion processes may give rise to greater greenhouse gas emissions than the dilute acid conversion process, even though the dilute acid process has a somewhat lower ethanol yield. Conclusion The lignocellulosic ethanol supply chains considered here all lead to greenhouse gas savings relative to gasoline An important caveat to this is that if lignocellulosic ethanol production uses feedstocks that lead to indirect land-use change, or other significant consequential impacts, the benefit may be greatly reduced. Co-locating ethanol, electricity generation and enzyme production in a single facility may improve performance, particularly if this allows the number of energy intensive steps in enzyme production to be reduced, or if other process synergies are available. If biofuels policy in the EU remains contingent on favourable environmental performance then the multi-scale nature of bioenergy supply chains presents a genuine challenge. Lignocellulosic ethanol holds promise for emission reductions, but maximising greenhouse gas savings will not only require efficient supply chain design but also a better understanding of the spatial and temporal factors which affect overall performance. PMID:19682352

Ethanol distribution, dispensing, and use: analysis of a portion of the biomass-to-biofuels supply chain using system dynamics.

PubMed

Vimmerstedt, Laura J; Bush, Brian; Peterson, Steve

2012-01-01

The Energy Independence and Security Act of 2007 targets use of 36 billion gallons of biofuels per year by 2022. Achieving this may require substantial changes to current transportation fuel systems for distribution, dispensing, and use in vehicles. The U.S. Department of Energy and the National Renewable Energy Laboratory designed a system dynamics approach to help focus government action by determining what supply chain changes would have the greatest potential to accelerate biofuels deployment. The National Renewable Energy Laboratory developed the Biomass Scenario Model, a system dynamics model which represents the primary system effects and dependencies in the biomass-to-biofuels supply chain. The model provides a framework for developing scenarios and conducting biofuels policy analysis. This paper focuses on the downstream portion of the supply chain-represented in the distribution logistics, dispensing station, and fuel utilization, and vehicle modules of the Biomass Scenario Model. This model initially focused on ethanol, but has since been expanded to include other biofuels. Some portions of this system are represented dynamically with major interactions and feedbacks, especially those related to a dispensing station owner's decision whether to offer ethanol fuel and a consumer's choice whether to purchase that fuel. Other portions of the system are modeled with little or no dynamics; the vehicle choices of consumers are represented as discrete scenarios. This paper explores conditions needed to sustain an ethanol fuel market and identifies implications of these findings for program and policy goals. A large, economically sustainable ethanol fuel market (or other biofuel market) requires low end-user fuel price relative to gasoline and sufficient producer payment, which are difficult to achieve simultaneously. Other requirements (different for ethanol vs. other biofuel markets) include the need for infrastructure for distribution and dispensing and widespread use of high ethanol blends in flexible-fuel vehicles.

Ethanol Distribution, Dispensing, and Use: Analysis of a Portion of the Biomass-to-Biofuels Supply Chain Using System Dynamics

PubMed Central

Vimmerstedt, Laura J.; Bush, Brian; Peterson, Steve

2012-01-01

The Energy Independence and Security Act of 2007 targets use of 36 billion gallons of biofuels per year by 2022. Achieving this may require substantial changes to current transportation fuel systems for distribution, dispensing, and use in vehicles. The U.S. Department of Energy and the National Renewable Energy Laboratory designed a system dynamics approach to help focus government action by determining what supply chain changes would have the greatest potential to accelerate biofuels deployment. The National Renewable Energy Laboratory developed the Biomass Scenario Model, a system dynamics model which represents the primary system effects and dependencies in the biomass-to-biofuels supply chain. The model provides a framework for developing scenarios and conducting biofuels policy analysis. This paper focuses on the downstream portion of the supply chain–represented in the distribution logistics, dispensing station, and fuel utilization, and vehicle modules of the Biomass Scenario Model. This model initially focused on ethanol, but has since been expanded to include other biofuels. Some portions of this system are represented dynamically with major interactions and feedbacks, especially those related to a dispensing station owner’s decision whether to offer ethanol fuel and a consumer’s choice whether to purchase that fuel. Other portions of the system are modeled with little or no dynamics; the vehicle choices of consumers are represented as discrete scenarios. This paper explores conditions needed to sustain an ethanol fuel market and identifies implications of these findings for program and policy goals. A large, economically sustainable ethanol fuel market (or other biofuel market) requires low end-user fuel price relative to gasoline and sufficient producer payment, which are difficult to achieve simultaneously. Other requirements (different for ethanol vs. other biofuel markets) include the need for infrastructure for distribution and dispensing and widespread use of high ethanol blends in flexible-fuel vehicles. PMID:22606230

Process integration possibilities for biodiesel production from palm oil using ethanol obtained from lignocellulosic residues of oil palm industry.

PubMed

Gutiérrez, Luis F; Sánchez, Oscar J; Cardona, Carlos A

2009-02-01

In this paper, integration possibilities for production of biodiesel and bioethanol using a single source of biomass as a feedstock (oil palm) were explored through process simulation. The oil extracted from Fresh Fruit Bunches was considered as the feedstock for biodiesel production. An extractive reaction process is proposed for transesterification reaction using in situ produced ethanol, which is obtained from two types of lignocellulosic residues of palm industry (Empty Fruit Bunches and Palm Press Fiber). Several ways of integration were analyzed. The integration of material flows between ethanol and biodiesel production lines allowed a reduction in unit energy costs down to 3.4%, whereas the material and energy integration leaded to 39.8% decrease of those costs. The proposed integrated configuration is an important option when the technology for ethanol production from biomass reaches such a degree of maturity that its production costs be comparable with those of grain or cane ethanol.

Decomposition pathways of C2 oxygenates on Rh-modified tungsten carbide surfaces

DOE PAGES

Kelly, Thomas G.; Ren, Hui; Chen, Jingguang G.

2015-03-27

Ethanol decomposition on tungsten monocarbide (WC) and Rh-modified WC was investigated using ultrahigh vacuum (UHV) surface science experiments and density functional theory (DFT) calculations. DFT calculations indicated that the binding energies of ethanol and its decomposition intermediates on WC(0001) were modified by Rh, with Rh/WC(0001) showing similar values to those on Rh(111). Through temperature-programmed desorption (TPD) experiments on polycrystalline WC and Rh-modified WC, it was shown that the selectivity for ethanol decomposition was different on these surfaces. On WC, the C-O bond of ethanol was preferentially broken to produce ethylene; on Rh-modified WC, the C-C bond was broken to producemore » carbon monoxide and methane. In addition, high-resolution electron energy loss spectroscopy (HREELS) was used to determine likely surface intermediates. On Rh-modified WC, ethanol first formed ethoxy through O-H scission, then reacted through an aldehyde intermediate to form the C1 products.« less

Life cycle assessment of ethanol derived from sawdust.

PubMed

Roy, Poritosh; Dutta, Animesh

2013-12-01

The life cycle of ethanol derived from sawdust by enzymatic hydrolysis process is evaluated to determine if environmentally preferable and economically viable ethanol can be produced. Two scenarios are considered to estimate net energy consumption, greenhouse gas (GHG) emission and production costs. The estimated net energy consumption, GHG emission and production costs are 12.29-13.37 MJ/L, 0.75-0.92 kg CO2 e/L and about $0.98-$1.04/L, respectively depending on the scenarios of this study. The result confirmed that environmental benefit can be gained with present technologies; however, economic viability remains doubtful unless Feed-in Tariff (FiT) is considered. The production cost of ethanol reduces to $0.5/L, if FiT is considered to be $0.025/MJ. This study indicates that the implementation of FiT program for ethanol industry not only helps Ontario mitigate GHG emissions, but may also attract more investment and create rural employment opportunities. Copyright © 2013 Elsevier Ltd. All rights reserved.

Hydrothermal Gasification for Waste to Energy

NASA Astrophysics Data System (ADS)

Epps, Brenden; Laser, Mark; Choo, Yeunun

2014-11-01

Hydrothermal gasification is a promising technology for harvesting energy from waste streams. Applications range from straightforward waste-to-energy conversion (e.g. municipal waste processing, industrial waste processing), to water purification (e.g. oil spill cleanup, wastewater treatment), to biofuel energy systems (e.g. using algae as feedstock). Products of the gasification process are electricity, bottled syngas (H2 + CO), sequestered CO2, clean water, and inorganic solids; further chemical reactions can be used to create biofuels such as ethanol and biodiesel. We present a comparison of gasification system architectures, focusing on efficiency and economic performance metrics. Various system architectures are modeled computationally, using a model developed by the coauthors. The physical model tracks the mass of each chemical species, as well as energy conversions and transfers throughout the gasification process. The generic system model includes the feedstock, gasification reactor, heat recovery system, pressure reducing mechanical expanders, and electricity generation system. Sensitivity analysis of system performance to various process parameters is presented. A discussion of the key technological barriers and necessary innovations is also presented.

Sustainable Biofuels A Transitions Approach to Understanding the Global Expansion of Ethanol and Biodiesel

NASA Astrophysics Data System (ADS)

Cottes, Jeffrey Jacob

Between 1998 and 2008, the promise of biofuels to increase rural development, enhance energy security, and reduce greenhouse gas emissions stimulated their diffusion across international markets. This rapid expansion of ethanol and biodiesel encouraged many jurisdictions to implement biofuels expansion policies and programs. Global biofuels, characterised by mass production and international trade of ethanol and biodiesel, occurred despite their long history as marginal technologies on the fringe of the petroleum-based transportation energy regime. The first purpose of this dissertation is to examine the global expansion of ethanol and biodiesel to understand how these recurrent socio-technological failures co-evolved with petroleum transportation fuels. Drawing from the field of socio-technical transitions, this dissertation also assesses the global expansion of ethanol and biodiesel to determine whether or not these first generation biofuels are sustainable. Numerous studies have assessed the technical effects of ethanol and biodiesel, but effects-based technical assessments of transport biofuels are unable to explain the interaction of wider system elements. The configuration of multi-level factors (i.e., niche development, the technological regime, and the socio-technical landscape) informs the present and emerging social functions of biofuels, which become relevant when determining how biofuels might become a sustainable energy option. The biofuels regimes that evolved in Brazil, the United States, and the European Union provide case studies show how ethanol and biodiesel expanded from fringe fuels to global commodities. The production infrastructures within these dominant biofuels regimes contribute to a persistence of unsustainable first generation biofuels that can inhibit the technical development and sustainability of biofuels. However, new and emerging ethanol and biodiesel markets are relatively small in comparison to the dominant regimes, and can readily adapt to technical and regulatory change. This dissertation argues that dominant biofuels regimes have not produced a sustainable energy option. It explores the Canadian case to evaluate the opportunities for niche development, and suggests that small markets can develop niche innovations by regulating the insertion of sustainability criteria in order to de-align the dominant trajectory of global biofuels production regimes and encourage their re-alignment in a more sustainable configuration.

Effect of corn stover compositional variability on minimum ethanol selling price (MESP).

PubMed

Tao, Ling; Templeton, David W; Humbird, David; Aden, Andy

2013-07-01

A techno-economic sensitivity analysis was performed using a National Renewable Energy Laboratory (NREL) 2011 biochemical conversion design model varying feedstock compositions. A total of 496 feedstock near infrared (NIR) compositions from 47 locations in eight US Corn Belt states were used as the inputs to calculate minimum ethanol selling price (MESP), ethanol yield (gallons per dry ton biomass feedstock), ethanol annual production, as well as total installed project cost for each composition. From this study, the calculated MESP is $2.20 ± 0.21 (average ± 3 SD) per gallon ethanol. Copyright © 2013. Published by Elsevier Ltd.

Making use of renewable energy

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

Johnston, J.C.

1984-01-01

This book describes renewable energy projects proposed for the rural areas of developing countries. Topics considered include biogas generation in Zimbabwe, biogas technology for water pumping in Botswana, soil fertility and energy problems in rural development in the Zaire rain forest, international scientific collaboration on biogas technologies for rural development, alcohol from biomass, an ethanol project in Zimbabwe, biomass alcohol and the fuel-food issue, solar water heating in Zimbabwe, absorbent box solar cookers, solar crop drying in Zimbabwe, the use of passive solar energy in Botswana buildings, the potential of mini hydro systems, woodfuel as a potential renewable energy source,more » small-scale afforestation for domestic needs in the communal lands of Zimbabwe, muscle power, the use of human energy in construction, hand-operated water pumps, animal power for water pumping in Botswana, the production of charcoal in Zambia, improving the efficiency of a traditional charcoal-burning Burmese cooking stove, social impacts, non-engineering constraints affecting energy use in a rural area, women and energy, and non-technical factors influencing the establishment of fuels-from-crops industries in developing countries.« less

Impacts of retrofitting analysis on first generation ethanol production: process design and techno-economics.

PubMed

Rajendran, Karthik; Rajoli, Sreevathsava; Teichert, Oliver; Taherzadeh, Mohammad J

2015-02-01

More than half of the bioethanol plants in operation today use corn or grains as raw materials. The downstream processing of mash after fermentation to produce ethanol and distiller grains is an energy-demanding process, which needs retrofitting for optimization. In addition, the fluctuation in the ethanol and grain prices affects the overall profitability of the plant. For this purpose, a process simulation was performed in Aspen Plus(®) based on an existing industrial plant located in Sweden. The simulations were compared using different scenarios including different concentrations of ethanol, using the stillage for biogas production to produce steam instead of distiller grains as a by-product, and altering the purity of the ethanol produced. Using stillage for biogas production, as well as utilizing the steam, reduced the overall energy consumption by 40% compared to the plant in operation. The fluctuations in grain prices had a high impact on the net present value (NPV), where grain prices greater than 349 USD/ton reached a zero NPV. After 20 years, the plant in operation producing 41,600 tons ethanol/year can generate a profit of 78 million USD. Compared to the base case, the less purified ethanol resulted in a lower NPV of 30 million USD.

Novel DDR Processing of Corn Stover Achieves High Monomeric Sugar Concentrations from Enzymatic Hydrolysis (230 g/L) and High Ethanol Concentration (10% v/v) During Fermentation

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

Chen, Xiaowen; Jennings, Ed; Shekiro, Joe

Distilling and purifying ethanol, butanol, and other products from second and later generation lignocellulosic biorefineries adds significant capital and operating cost for biofuels production. The energy costs associated with distillation affects plant gate and life cycle analysis costs. Lower titers in fermentation due to lower sugar concentrations from pretreatment increase both energy and production costs. In addition, higher titers decrease the volumes required for enzymatic hydrolysis and fermentation vessels. Therefore, increasing biofuels titers has been a research focus in renewable biofuels production for several decades. In this work, we achieved over 200 g/L of monomeric sugars after high solids enzymaticmore » hydrolysis using the novel deacetylation and disc refining (DDR) process on corn stover. The high sugar concentrations and low chemical inhibitor concentrations from the DDR process allowed ethanol titers as high as 82 g/L in 22 hours, which translates into approximately 10 vol% ethanol. To our knowledge, this is the first time that 10 vol% ethanol in fermentation derived from corn stover without any sugar concentration or purification steps has been reported. Techno-economic analysis shows the higher titer ethanol achieved from the DDR process could significantly reduce the minimum ethanol selling price from cellulosic biomass.« less

Structure stability of HKUST-1 towards water and ethanol and their effect on its CO2 capture properties.

PubMed

Álvarez, J Raziel; Sánchez-González, Elí; Pérez, Eric; Schneider-Revueltas, Emilia; Martínez, Ana; Tejeda-Cruz, Adriana; Islas-Jácome, Alejandro; González-Zamora, Eduardo; Ibarra, Ilich A

2017-07-18

Water and ethanol stabilities of the crystal structure of the Cu-based metal-organic framework (MOF) HKUST-1 have been investigated. Vapour (water and ethanol) sorption isotherms and cyclability were measured by a dynamic strategy. The ethanol sorption capacity of HKUST-1 at 303 K remained unchanged contrasting water sorption (which decreased along with the sorption experiment time). Considering the binding energy of each sorbate with the open Cu(ii) sites, obtained by the use of diffusion coefficients, we showed the superior crystal stability of the HKUST-1 framework towards ethanol. Finally, a small quantity of ethanol (pre-adsorbed) slightly enhanced CO 2 capture without crystal structure degradation.

Promoting Bio-Ethanol in the United States by Incorporating Lessons from Brazil's National Alcohol Program

ERIC Educational Resources Information Center

Du, Yangbo

2007-01-01

Current U.S. energy policy supports increasing the use of bio-ethanol as a gasoline substitute, which Brazil first produced on a large scale in response to the 1970s energy crises. Brazil's National Alcohol Program stood out among its contemporaries regarding its success at displacing a third of Brazil's gasoline requirements, primarily due to…

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.

Biosynthetic burden and plasmid burden limit expression of chromosomally integrated heterologous genes (pdc, adhB) in Escherichia coli

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

Martinez, A.; York, S.W.; Yomano, L.P.

1999-10-01

Previous studies have shown an unexpectedly high nutrient requirement for efficient ethanol production by ethanologenic recombinants of Escherichia coli B such as LY01 which contain chromosomally integrated Zymomonas mobilis genes (pdc, adhB) encoding the ethanol pathway. The basis for this requirement has been identified as a media-dependent effect on the expression of the Z. mobilis genes rather than a nutritional limitation. Ethanol production was substantially increased without additional nutrients simply by increasing the level of pyruvate decarboxylase activity. This was accomplished by adding a multicopy plasmid containing pdc alone (but not adhB alone) to strain LY01, and by adding multicopymore » plasmids which express pdc and adhB from strong promoters. New strong promoters were isolated from random fragments of Z. mobilis DNA and characterized but were not used to construct integrated biocatalysts. These promoters contained regions resembling recognition sites for 3 different E. coli sigma factors: {sigma}{sup 70}, {sigma}{sup 38}, and {sigma}{sup 28}. The most effective plasmid-based promoters for fermentation were recognized by multiple sigma factors, expressed both pdc and adhB at high levels, and produced ethanol efficiently while allowing up to 80% reduction in complex nutrients as compared to LY01. The ability to utilize multiple sigma factors may be advantageous to maintain the high levels of PDC and ADH needed for efficient ethanol production throughout batch fermentation.« less

Adaptation of the xylose fermenting yeast Saccharomyces cerevisiae F12 for improving ethanol production in different fed-batch SSF processes.

PubMed

Tomás-Pejó, E; Ballesteros, M; Oliva, J M; Olsson, L

2010-11-01

An efficient fermenting microorganism for bioethanol production from lignocellulose is highly tolerant to the inhibitors released during pretreatment and is able to ferment efficiently both glucose and xylose. In this study, directed evolution was employed to improve the xylose fermenting Saccharomyces cerevisiae F12 strain for bioethanol production at high substrate loading. Adapted and parental strains were compared with respect to xylose consumption and ethanol production. Adaptation led to an evolved strain more tolerant to the toxic compounds present in the medium. When using concentrated prehydrolysate from steam-pretreated wheat straw with high inhibitor concentration, an improvement of 65 and 20% in xylose consumption and final ethanol concentration, respectively, were achieved using the adapted strain. To address the need of high substrate loadings, fed-batch SSF experiments were performed and an ethanol concentration as high as 27.4 g/l (61% of the theoretical) was obtained with 11.25% (w/w) of water insoluble solids (WIS).

Vitamin B1-catalyzed acetoin formation from acetaldehyde: a key step for upgrading bioethanol to bulk C₄ chemicals.

PubMed

Lu, Ting; Li, Xiukai; Gu, Liuqun; Zhang, Yugen

2014-09-01

The production of bulk chemicals and fuels from renewable biobased feedstocks is of significant importance for the sustainability of human society. The production of ethanol from biomass has dramatically increased and bioethanol also holds considerable potential as a versatile building block for the chemical industry. Herein, we report a highly selective process for the conversion of ethanol to C4 bulk chemicals, such as 2,3-butanediol and butene, via a vitamin B1 (thiamine)-derived N-heterocyclic carbene (NHC)-catalyzed acetoin condensation as the key step to assemble two C2 acetaldehydes into a C4 product. The environmentally benign and cheap natural catalyst vitamin B1 demonstrates high selectivity (99%), high efficiency (97% yield), and high tolerance toward ethanol and water impurities in the acetoin reaction. The results enable a novel and efficient process for ethanol upgrading. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Unusual attempt to direct the growth of bimetallic Ag@Pt nanorods on electrochemically reduced graphene oxide nanosheets by electroless exchange of Cu by Pt for an efficient alcohol oxidation

NASA Astrophysics Data System (ADS)

Jeena, S. E.; Gnanaprakasam, P.; Selvaraju, T.

2017-01-01

A simple and an efficient tool for the direct growth of bimetallic Ag@Pt nanorods (NRDs) on electrochemically reduced graphene oxide (ERGO) nanosheets was developed at glassy carbon electrode (GCE). Initially, Cu shell was grown on Ag core as Ag@Cu NRD by the seed-mediated growth method. Accordingly, Cu shell has been successfully replaced by Pt using the electroless galvanic replacement method with ease by effective functionalization of L-tryptophan on ERGO surface (L-ERGO), which eventually plays an important role in the direct growth of one-dimensional bimetallic NRDs. As a result, the synthesized Ag@Pt NRD-supported L-ERGO nanosheets (Ag@Pt NRDs/L-ERGO/GCE) were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDAX) and Raman spectroscopy. Anodic stripping voltammetry was used to explore its electrochemical properties. Finally, the developed bimetallic Ag@Pt NRDs/L-ERGO/GCEs were studied as a better electrocatalyst compared to the commercial catalysts such as Pt40/C or Pt20/C-loaded electrode for the oxidation of ethanol or methanol with a high tolerance level and an enhanced current density. In addition, the long-term stability was studied using chronoamperometry for 1000 s at the bimetallic NRD electrode for alcohol oxidation which impedes the fouling properties. The unfavourable and favourable electrooxidation of ethanol at Ag@Cu NRDs/L-ERGO/GCE (a) and Ag@Pt NRDs/L-ERGO/GCE (b) is discussed. The synergistic effect of Ag core and catalytic properties of Pt shell at Ag@Pt NRDs/L-ERGO/GCE tend to strongly minimize the CO poisoning effect and enhanced ethanol electrooxidation.

Hemicellulosic ethanol production by immobilized cells of Scheffersomyces stipitis: Effect of cell concentration and stirring

PubMed Central

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

2015-01-01

Bioconversion of hemicellulosic hydrolysate into ethanol plays a pivotal role in the overall success of biorefineries. For the efficient fermentative conversion of hemicellulosic hydrolysates into ethanol, the use of immobilized cells system could provide the enhanced ethanol productivities with significant time savings. Here, we investigated the effect of 2 important factors (e.g., cell concentration and stirring) on ethanol production from sugarcane bagasse hydrolysate using the yeast Scheffersomyces stipitis immobilized in calcium alginate matrix. A 22 full factorial design of experiment was performed considering the process variables- immobilized cell concentration (3.0, 6.5 and 10.0 g/L) and stirring (100, 200 and 300 rpm). Statistical analysis showed that stirring has the major influence on ethanol production. Maximum ethanol production (8.90 g/l) with ethanol yield (Yp/s) of 0.33 g/g and ethanol productivity (Qp) of 0.185 g/l/h was obtained under the optimized process conditions (10.0 g/L of cells and 100 rpm). PMID:25488725

Composition of sugar cane, energy cane, and sweet sorghum suitable for ethanol production at Louisiana sugar mills.

PubMed

Kim, Misook; Day, Donal F

2011-07-01

A challenge facing the biofuel industry is to develop an economically viable and sustainable biorefinery. The existing potential biorefineries in Louisiana, raw sugar mills, operate only 3 months of the year. For year-round operation, they must adopt other feedstocks, besides sugar cane, as supplemental feedstocks. Energy cane and sweet sorghum have different harvest times, but can be processed for bio-ethanol using the same equipment. Juice of energy cane contains 9.8% fermentable sugars and that of sweet sorghum, 11.8%. Chemical composition of sugar cane bagasse was determined to be 42% cellulose, 25% hemicellulose, and 20% lignin, and that of energy cane was 43% cellulose, 24% hemicellulose, and 22% lignin. Sweet sorghum was 45% cellulose, 27% hemicellulose, and 21% lignin. Theoretical ethanol yields would be 3,609 kg per ha from sugar cane, 12,938 kg per ha from energy cane, and 5,804 kg per ha from sweet sorghum.

Influence of polar solvents on photovoltaic performance of Monascusred dye-sensitized solar cell

NASA Astrophysics Data System (ADS)

Lee, Jae Wook; Kim, Tae Young; Ko, Hyun Seok; Han, Shin; Lee, Suk-Ho; Park, Kyung Hee

Dye-sensitized solar cells (DSSCs) were assembled using natural dyes extracted from Monascus red pigment as a sensitizer. In this work, we studied the adsorption characteristics for harvesting sunlight and the electrochemical behavior for electron transfer in Monascus red DSSC using different solvents. The effect of polar aprotic and protic solvents including water, ethanol, and dimethylsulfoxide (DMSO) used in the sensitization process was investigated for the improvement in conversion efficiency of a cell. As for the Monascus red dye-sensitized electrode in DMSO solvent, the solar cell yields a short-circuit current density (Jsc) of 1.23 mA/cm2, a photovoltage (Voc) of 0.75 V, and a fill factor of 0.72, corresponding to an energy conversion efficiency (η) of 0.66%.

Optimization of VFAs and ethanol production with waste sludge used as the denitrification carbon source.

PubMed

Guo, Liang; Zhang, Jiawen; Yin, Li; Zhao, Yangguo; Gao, Mengchun; She, Zonglian

2015-01-01

An acidification metabolite such as volatile fatty acids (VFAs) and ethanol could be used as denitrification carbon sources for solving the difficult problem of carbon source shortages and low nitrogen removal efficiency. A proper control of environmental factors could be essential for obtaining the optimal contents of VFAs and ethanol. In this study, suspended solids (SS), oxidation reduction potential (ORP) and shaking rate were chosen to investigate the interactive effects on VFAs and ethanol production with waste sludge. It was indicated that T-VFA yield could be enhanced at lower ORP and shaking rate. Changing the SS, ORP and shaking rate could influence the distribution of acetic, propionic, butyric, valeric acids and ethanol. The optimal conditions for VFAs and ethanol production used as a denitrification carbon source were predicted by analyzing response surface methodology (RSM).

Feasibility study report for the Imperial Valley Ethanol Refinery: a 14. 9-million-gallon-per-year ethanol synfuel refinery utilizing geothermal energy

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

Not Available

1981-03-01

The construction and operation of a 14,980,000 gallon per year fuel ethanol from grain refinery in the Imperial Valley of California is proposed. The Imperial Valley Ethanol Refinery (refinery) will use hot geothermal fluid from geothermal resources at the East Mesa area as the source of process energy. In order to evaluate the economic viability of the proposed Project, exhaustive engineering, cost analysis, and financial studies have been undertaken. This report presents the results of feasibility studies undertaken in geothermal resource, engineering, marketing financing, management, environment, and permits and approvals. The conclusion of these studies is that the Project ismore » economically viable. US Alcohol Fuels is proceeding with its plans to construct and operate the Refinery.« less

Bioenergy from stillage anaerobic digestion to enhance the energy balance ratio of ethanol production.

PubMed

Fuess, Lucas Tadeu; Garcia, Marcelo Loureiro

2015-10-01

The challenges associated with the availability of fossil fuels in the past decades intensified the search for alternative energy sources, based on an ever-increasing demand for energy. In this context, the application of anaerobic digestion (AD) as a core treatment technology in industrial plants should be highlighted, since this process combines the pollution control of wastewaters and the generation of bioenergy, based on the conversion of the organic fraction to biogas, a methane-rich gaseous mixture that may supply the energetic demands in industrial plants. In this context, this work aimed at assessing the energetic potential of AD applied to the treatment of stillage, the main wastewater from ethanol production, in an attempt to highlight the improvements in the energy balance ratio of ethanol by inserting the heating value of methane as a bioenergy source. At least 5-15% of the global energy consumption in the ethanol industry could be supplied by the energetic potential of stillage, regardless the feedstock (i.e. sugarcane, corn or cassava). The association between bagasse combustion and stillage anaerobic digestion in sugarcane-based distilleries could provide a bioenergy surplus of at least 130% of the total fossil fuel input into the ethanol plant, considering only the energy from methane. In terms of financial aspects, the economic gains could reach US$ 0.1901 and US$ 0.0512 per liter of produced ethanol, respectively for molasses- (Brazil) and corn-based (EUA) production chains. For large-scale (∼1000 m(3)EtOH per day) Brazilian molasses-based plants, an annual economic gain of up to US$ 70 million could be observed. Considering the association between anaerobic and aerobic digestion, for the scenarios analyzed, at least 25% of the energetic potential of stillage would be required to supply the energy consumption with aeration, however, more suitable effluents for agricultural application could be produced. The main conclusion from this work indicates that anaerobic processes should be considered the core technology to treat stillage, based mainly on the attractive relation energy generation-financial return and on the possibility to keep the advantages inherent to the common fertigation when using the treated effluent in agriculture. Copyright © 2015 Elsevier Ltd. All rights reserved.

Interactions on External MOF Surfaces: Desorption of Water and Ethanol from CuBDC Nanosheets.

PubMed

Elder, Alexander C; Aleksandrov, Alexandr B; Nair, Sankar; Orlando, Thomas M

2017-10-03

The external surfaces of metal-organic framework (MOF) materials are difficult to experimentally isolate due to the high porosities of these materials. MOF surface surrogates in the form of copper benzenedicarboxylate (CuBDC) nanosheets were synthesized using a bottom-up approach, and the surface interactions of water and ethanol were investigated by temperature-programmed desorption (TPD). A method of analysis of diffusion-influenced TPD was developed to measure the desorption properties of these porous materials. This approach also allows the extraction of diffusion coefficients from TPD data. The transmission Fourier transform infrared spectra, powder X-ray diffraction patterns, and TPD data indicate that water desorbs from CuBDC nanosheets with activation energies of 44 ± 2 kJ/mol at edge sites and 58 ± 1 kJ/mol at external surface and internal and pore sites. Ethanol desorbs with activation energies of 58 ± 1 kJ/mol at internal pore sites and 66 ± 0.4 kJ/mol at external surface sites. Co-adsorption of water and ethanol was also investigated. The presence of ethanol was found to inhibit the desorption of water, resulting in a water desorption process with an activation energy of 68 ± 0.7 kJ/mol.

Degradation of Acetaldehyde and Its Precursors by Pelobacter carbinolicus and P. acetylenicus

PubMed Central

Schmidt, Alexander; Frensch, Marco; Schleheck, David; Schink, Bernhard; Müller, Nicolai

2014-01-01

Pelobacter carbinolicus and P. acetylenicus oxidize ethanol in syntrophic cooperation with methanogens. Cocultures with Methanospirillum hungatei served as model systems for the elucidation of syntrophic ethanol oxidation previously done with the lost “Methanobacillus omelianskii” coculture. During growth on ethanol, both Pelobacter species exhibited NAD+-dependent alcohol dehydrogenase activity. Two different acetaldehyde-oxidizing activities were found: a benzyl viologen-reducing enzyme forming acetate, and a NAD+-reducing enzyme forming acetyl-CoA. Both species synthesized ATP from acetyl-CoA via acetyl phosphate. Comparative 2D-PAGE of ethanol-grown P. carbinolicus revealed enhanced expression of tungsten-dependent acetaldehyde: ferredoxin oxidoreductases and formate dehydrogenase. Tungsten limitation resulted in slower growth and the expression of a molybdenum-dependent isoenzyme. Putative comproportionating hydrogenases and formate dehydrogenase were expressed constitutively and are probably involved in interspecies electron transfer. In ethanol-grown cocultures, the maximum hydrogen partial pressure was about 1,000 Pa (1 mM) while 2 mM formate was produced. The redox potentials of hydrogen and formate released during ethanol oxidation were calculated to be EH2 = -358±12 mV and EHCOOH = -366±19 mV, respectively. Hydrogen and formate formation and degradation further proved that both carriers contributed to interspecies electron transfer. The maximum Gibbs free energy that the Pelobacter species could exploit during growth on ethanol was −35 to −28 kJ per mol ethanol. Both species could be cultivated axenically on acetaldehyde, yielding energy from its disproportionation to ethanol and acetate. Syntrophic cocultures grown on acetoin revealed a two-phase degradation: first acetoin degradation to acetate and ethanol without involvement of the methanogenic partner, and subsequent syntrophic ethanol oxidation. Protein expression and activity patterns of both Pelobacter spp. grown with the named substrates were highly similar suggesting that both share the same steps in ethanol and acetalydehyde metabolism. The early assumption that acetaldehyde is a central intermediate in Pelobacter metabolism was now proven biochemically. PMID:25536080

Effects of Alloyed Metal on the Catalysis Activity of Pt for Ethanol Partial Oxidation: Adsorption and Dehydrogenation on Pt3M (M=Pt, Ru, Sn, Re, Rh, and Pd)

PubMed Central

Xu, Zhen-Feng; Wang, Yixuan

2011-01-01

The adsorption and dehydrogenation reactions of ethanol over bimetallic clusters, Pt3M (M = Pt, Ru, Sn, Re, Rh, and Pd), have been extensively investigated with density functional theory. Both the α-hydrogen and hydroxyl adsorptions on Pt as well as on the alloyed transition metal M sites of PtM were considered as initial reaction steps. The adsorptions of ethanol on Pt and M sites of some PtM via the α-hydrogen were well established. Although the α-hydrogen adsorption on Pt site is weaker than the hydroxyl, the potential energy profiles show that the dehydrogenation via the α-hydrogen path has much lower energy barrier than that via the hydroxyl path. Generally for the α-hydrogen path the adsorption is a rate-determining-step because of rather low dehydrogenation barrier for the α-hydrogen adsorption complex (thermodynamic control), while the hydroxyl path is determined by its dehydrogenation step (kinetic control). The effects of alloyed metal on the catalysis activity of Pt for ethanol partial oxidation, including adsorption energy, energy barrier, electronic structure, and eventually rate constant were discussed. Among all of the alloyed metals only Sn enhances the rate constant of the dehydrogenation via the α-hydrogen path on the Pt site of Pt3Sn as compared with Pt alone, which interprets why the PtSn is the most active to the oxidation of ethanol. PMID:22102920

Can ethanol alone meet California's low carbon fuel standard? An evaluation of feedstock and conversion alternatives

NASA Astrophysics Data System (ADS)

Zhang, Yimin; Joshi, Satish; MacLean, Heather L.

2010-01-01

The feasibility of meeting California's low carbon fuel standard (LCFS) using ethanol from various feedstocks is assessed. Lifecycle greenhouse gas (GHG) emissions, direct agricultural land use, petroleum displacement directly due to ethanol blending, and production costs for a number of conventional and lignocellulosic ethanol pathways are estimated under various supply scenarios. The results indicate that after considering indirect land use effects, all sources of ethanol examined, except Midwest corn ethanol, are viable options to meet the LCFS. However, the required ethanol quantity depends on the GHG emissions performance and ethanol availability. The quantity of ethanol that can be produced from lignocellulosic biomass resources within California is insufficient to meet the year 2020 LCFS target. Utilizing lignocellulosic ethanol to meet the LCFS is more attractive than utilizing Brazilian sugarcane ethanol due to projected lower direct agricultural land use, dependence on imported energy, ethanol cost, required refueling infrastructure modifications and penetration of flexible fuel E85 vehicles. However, advances in cellulosic ethanol technology and commercial production capacity are required to support moderate- to large-scale introduction of low carbon intensity cellulosic ethanol. Current cellulosic ethanol production cost estimates suffer from relatively high uncertainty and need to be refined based on commercial scale production data when available.

The Ethanol Project: Exploring Alternative Energy with Role-Play and Writing

ERIC Educational Resources Information Center

Winter, Julia

2013-01-01

This article describes a project that includes a two-week series of researching, essay writing, and speaking lessons exploring the broader implications of using ethanol as a fuel. The author, a chemistry teacher, describes how she uses a senate hearing discussion of ethanol fuel subsidies as the forum for a role-play. The four components of the…

Survey of mycotoxins in corn distillers’ dried grains with solubles from seventy-eight ethanol plants in twelve states the U.S. in 2011

USDA-ARS?s Scientific Manuscript database

Fuel ethanol co-products known as distillers’ dried grains with solubles (DDGS) are a significant source of energy, protein, and phosphorous in animal feed. Fuel ethanol production may concentrate mycotoxins present in corn into DDGS. One hundred and forty one corn DDGS lots collected in 2011 from 7...

Maleic acid treatment of bioabated corn stover liquors improves cellulose conversion to ethanol

USDA-ARS?s Scientific Manuscript database

Elimination of inhibitory compounds released during pretreatment of lignocellulose is critical for efficient cellulose conversion and ethanol fermentation. This study examined the effect of bioabated liquor from pretreated corn stover on enzyme hydrolysis of Solka Floc or pretreated corn stover soli...

Improvement of dry fractionation ethanol fermentation by partial germ supplementation

USDA-ARS?s Scientific Manuscript database

Ethanol fermentation of dry fractionated grits (corn endosperm pieces) containing different levels of germ was studied using the dry grind process. Partial removal of germ fraction allows for marketing the germ fraction and potentially more efficient fermentation. Grits obtained from a dry milling p...

Mathematical modeling of the ethanol fermentation of cashew apple juice by a flocculent yeast: the effect of initial substrate concentration and temperature.

PubMed

Pinheiro, Álvaro Daniel Teles; da Silva Pereira, Andréa; Barros, Emanuel Meneses; Antonini, Sandra Regina Ceccato; Cartaxo, Samuel Jorge Marques; Rocha, Maria Valderez Ponte; Gonçalves, Luciana Rocha B

2017-08-01

In this work, the effect of initial sugar concentration and temperature on the production of ethanol by Saccharomyces cerevisiae CCA008, a flocculent yeast, using cashew apple juice in a 1L-bioreactor was studied. The experimental results were used to develop a kinetic model relating biomass, ethanol production and total reducing sugar consumption. Monod, Andrews, Levenspiel and Ghose and Tyagi models were investigated to represent the specific growth rate without inhibition, with inhibition by substrate and with inhibition by product, respectively. Model validation was performed using a new set of experimental data obtained at 34 °C and using 100 g L -1 of initial substrate concentration. The model proposed by Ghose and Tyagi was able to accurately describe the dynamics of ethanol production by S. cerevisiae CCA008 growing on cashew apple juice, containing an initial reducing sugar concentration ranging from 70 to 170 g L -1 and temperature, from 26 to 42 °C. The model optimization was also accomplished based on the following parameters: percentage volume of ethanol per volume of solution (%V ethanol /V solution ), efficiency and reaction productivity. The optimal operational conditions were determined using response surface graphs constructed with simulated data, reaching an efficiency and a productivity of 93.5% and 5.45 g L -1  h -1 , respectively.

Improved ethanol production from xylose in the presence of acetic acid by the overexpression of the HAA1 gene in Saccharomyces cerevisiae.

PubMed

Sakihama, Yuri; Hasunuma, Tomohisa; Kondo, Akihiko

2015-03-01

The hydrolysis of lignocellulosic biomass liberates sugars, primarily glucose and xylose, which are subsequently converted to ethanol by microbial fermentation. The rapid and efficient fermentation of xylose by recombinant Saccharomyces cerevisiae strains is limited by weak acids generated during biomass pretreatment processes. In particular, acetic acid negatively affects cell growth, xylose fermentation rate, and ethanol production. The ability of S. cerevisiae to efficiently utilize xylose in the presence of acetic acid is an essential requirement for the cost-effective production of ethanol from lignocellulosic hydrolysates. Here, an acetic acid-responsive transcriptional activator, HAA1, was overexpressed in a recombinant xylose-fermenting S. cerevisiae strain to yield BY4741X/HAA1. This strain exhibited improved cell growth and ethanol production from xylose under aerobic and oxygen limited conditions, respectively, in the presence of acetic acid. The HAA1p regulon enhanced transcript levels in BY4741X/HAA1. The disruption of PHO13, a p-nitrophenylphosphatase gene, in BY4741X/HAA1 led to further improvement in both yeast growth and the ability to ferment xylose, indicating that HAA1 overexpression and PHO13 deletion act by different mechanisms to enhance ethanol production. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Economic and environmental transportation effects of large-scale ethanol production and distribution in the United States.

PubMed

Wakeley, Heather L; Hendrickson, Chris T; Griffin, W Michael; Matthews, H Scott

2009-04-01

The combination of current and planned 2007 U.S. ethanol production capacity is 50 billion L/yr, one-third of the Energy Independence and Security Act of 2007 (EISA) target of 136 billion L of biofuels by 2022. In this study, we evaluate transportation impacts and infrastructure requirements for the use of E85 (85% ethanol, 15% gasoline) in light-duty vehicles using a combination of corn and cellulosic ethanol. Ethanol distribution is modeled using a linear optimization model. Estimated average delivered ethanol costs, in 2005 dollars, range from $0.29 to $0.62 per liter ($1.3-2.8 per gallon), depending on transportation distance and mode. Emissions from ethanol transport estimated in this work are up to 2 times those in previous ethanol LCA studies and thus lead to larger total life cycle effects. Long-distance transport of ethanol to the end user can negate ethanol's potential economic and environmental benefits relative to gasoline. To reduce costs, we recommend regional concentration of E85 blends for future ethanol production and use.

Abatement Cost of GHG Emissions for Wood-Based Electricity and Ethanol at Production and Consumption Levels

PubMed Central

Dwivedi, Puneet; Khanna, Madhu

2014-01-01

Woody feedstocks will play a critical role in meeting the demand for biomass-based energy products in the US. We developed an integrated model using comparable system boundaries and common set of assumptions to ascertain unit cost and greenhouse gas (GHG) intensity of electricity and ethanol derived from slash pine (Pinus elliottii) at the production and consumption levels by considering existing automobile technologies. We also calculated abatement cost of greenhouse gas (GHG) emissions with respect to comparable energy products derived from fossil fuels. The production cost of electricity derived using wood chips was at least cheaper by 1 ¢ MJ−1 over electricity derived from wood pellets. The production cost of ethanol without any income from cogenerated electricity was costlier by about 0.7 ¢ MJ−1 than ethanol with income from cogenerated electricity. The production cost of electricity derived from wood chips was cheaper by at least 0.7 ¢ MJ−1 than the energy equivalent cost of ethanol produced in presence of cogenerated electricity. The cost of using ethanol as a fuel in a flex-fuel vehicle was at least higher by 6 ¢ km−1 than a comparable electric vehicle. The GHG intensity of per km distance traveled in a flex-fuel vehicle was greater or lower than an electric vehicle running on electricity derived from wood chips depending on presence and absence of GHG credits related with co-generated electricity. A carbon tax of at least $7 Mg CO2e−1 and $30 Mg CO2e−1 is needed to promote wood-based electricity and ethanol production in the US, respectively. The range of abatement cost of GHG emissions is significantly dependent on the harvest age and selected baseline especially for electricity generation. PMID:24937461

Abatement cost of GHG emissions for wood-based electricity and ethanol at production and consumption levels.

PubMed

Dwivedi, Puneet; Khanna, Madhu

2014-01-01

Woody feedstocks will play a critical role in meeting the demand for biomass-based energy products in the US. We developed an integrated model using comparable system boundaries and common set of assumptions to ascertain unit cost and greenhouse gas (GHG) intensity of electricity and ethanol derived from slash pine (Pinus elliottii) at the production and consumption levels by considering existing automobile technologies. We also calculated abatement cost of greenhouse gas (GHG) emissions with respect to comparable energy products derived from fossil fuels. The production cost of electricity derived using wood chips was at least cheaper by 1 ¢ MJ-1 over electricity derived from wood pellets. The production cost of ethanol without any income from cogenerated electricity was costlier by about 0.7 ¢ MJ-1 than ethanol with income from cogenerated electricity. The production cost of electricity derived from wood chips was cheaper by at least 0.7 ¢ MJ-1 than the energy equivalent cost of ethanol produced in presence of cogenerated electricity. The cost of using ethanol as a fuel in a flex-fuel vehicle was at least higher by 6 ¢ km-1 than a comparable electric vehicle. The GHG intensity of per km distance traveled in a flex-fuel vehicle was greater or lower than an electric vehicle running on electricity derived from wood chips depending on presence and absence of GHG credits related with co-generated electricity. A carbon tax of at least $7 Mg CO2e-1 and $30 Mg CO2e-1 is needed to promote wood-based electricity and ethanol production in the US, respectively. The range of abatement cost of GHG emissions is significantly dependent on the harvest age and selected baseline especially for electricity generation.

Conditioned Reinforcement and Locomotor Activating Effects of Caffeine and Ethanol Combinations in Mice

PubMed Central

Hilbert, Megan L.T.; May, Christina E.; Griffin, William C.

2013-01-01

A growing trend among ethanol drinkers, especially young adults, is to combine caffeinated energy drinks with ethanol during a drinking episode. The primary active ingredient of these mixers is caffeine, which may significantly interact with ethanol. We tested the two hypotheses that caffeine would enhance ethanol-conditioned place preference and also enhance ethanol-stimulated locomotor activity. The interactive pharmacology of ethanol and caffeine was examined in C57BL/6J (B6) mice in a conditioned place preference procedure with 1.75 g/kg ethanol and 3 mg/kg caffeine. Additionally, we used B6 mice to evaluate ethanol/caffeine combinations on locomotor activity using 3 doses of ethanol (1.75, 2.5 and 3.25 g/kg) and 2 two doses of caffeine (3 and 15 mg/kg). Both ethanol and caffeine administered alone increased preference for the drug paired side, though the effect of caffeine was more modest than that of ethanol. The drug combination produced significant place preference itself, but this was not greater than that for ethanol alone. Additionally, the combination of caffeine and ethanol significantly increased locomotion compared to giving either drug alone. The effect was strongest with a stimulatory dose of ethanol (1.75 g/kg) and waned with increasing doses of ethanol. Thus, combinations of caffeine and ethanol had significant conditioned reinforcing and locomotor activating effects in mice. PMID:23872371

Resonance Energy Transfer Studies from Derivatives of Thiophene Substituted 1,3,4-Oxadiazoles to Coumarin-334 Dye in Liquid and Dye-Doped Polymer Media

NASA Astrophysics Data System (ADS)

Naik, Lohit; Deshapande, Narahari; Khazi, Imtiyaz Ahamed M.; Malimath, G. H.

2018-02-01

In the present work, we have carried out energy transfer studies using newly synthesised derivatives of thiophene substituted 1,3,4-oxadiazoles namely, 2-(-4-(thiophene-3-yl)phenyl)-5-(5-(thiophene-3-yl)thiophene-2-yl)-1,3,4-oxadiazole [TTO], 2-(-4-(benzo[b]thiophene-2-yl)phenyl)-5-(5-(benzo[b]thiophene-2-yl)-1,3,4-oxadiozole [TBO] and 2-(4-(4-(trifluoromethyl)phenyl)phenyl)-5-(5-(4-(trifluoromethyl)phenyl)thiophen-2-yl)-1,3,4-oxadiazole [TMO] as donors and laser dye coumarin-334 as acceptor in ethanol and dye-doped polymer (poly(methyl methacrylate) (PMMA)) media following steady-state and time-resolved fluorescence methods. Bimolecular quenching constant ( k q), translation diffusion rate parameter ( k d), diffusion length ( D l), critical transfer distance ( R 0), donor- acceptor distance ( r) and energy transfer efficiency ( E T) are calculated. It is observed that, critical transfer distance is more than the diffusion length for all the pairs. Further, bimolecular quenching constant is also more than the translation diffusion rate parameter. Hence, our experimental findings suggest that overall energy transfer is due to Förster resonance energy transfer (FRET) between donor and acceptor in both the media and for all the pairs. In addition, considerable increase in fluorescence intensity and energy transfer efficiency is observed in dye-doped polymer matrix systems as compared to liquid media. This suggests that, these donor-acceptor pairs doped in PMMA matrix may be used for applications such as energy transfer dye lasers (ETDL) to improve the efficiency and photostability, to enhance tunability and for plastic scintillation detectors.

What do cocktail parties and stressed trees have in common? Plenty of alcohol!

Treesearch

John Kirkland; Rick Kelsey

2015-01-01

Stress in trees is caused by disturbances such as fire, flood, disease, or insect infestations. A single stressor may not be enough to kill a tree, but a combination can be deadly.Tree tissues produce and accumulate ethanol in response to many stressors. Ethanol provides the stressed tissues with an emergency energy source when their normal source of energy...

Overview of feedstock research in the United States, Canada, and Brazil

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

Ferrell, J.; Tardif, M.L.; Couto, L.

1993-12-31

This is an overview of the current biomass feedstock efforts in Brazil, Canada, and the United States. The report from Brazil provides an historical perspective of incentive programs, the charcoal and fuelwood energy programs, the alcohol program, and other biomass energy efforts. The efforts in Brazil, particularly with the sugar cane to ethanol and the charcoal and fuelwood programs, dwarfs other commercial biomass systems in the Americas. One of the bright spots in the future is the Biomass Integrated Gasification/Gas Turbine Electricity Project initially funded in 1992. The sugar cane-based ethanol industry continues to develop higher yielding cane varieties andmore » more efficient microorganisms to convert the sugar cane carbohydrates into alcohol. In Canada a number of important institutions and enterprises taking part in the economical development of the country are involved in biomass research and development including various aspects of the biomass such as forestry, agricultural, industrial, urban, food processing, fisheries and peat bogs. Biomass feedstock research in the United States is evolving to reflect Department of Energy priorities. Greater emphasis is placed on leveraging research with the private sector contributing a greater share of funds, for both research and demonstration projects. The feedstock program, managed by ORNL, is focused on limited model species centered at a regional level using a multidisciplinary approach. Activities include a stronger emphasis on emerging environmental issues such as biodiversity, sustainability and habitat management. DOE also is a supporter of the National Biofuels Roundtable, which is developing principles for producing biomass energy in an economically viable and ecologically sound manner. Geographical Information Systems are also being developed as tools to quantify and characterize the potential supply of energy crops in various regions.« less

A new dawn for industrial photosynthesis.

PubMed

Robertson, Dan E; Jacobson, Stuart A; Morgan, Frederick; Berry, David; Church, George M; Afeyan, Noubar B

2011-03-01

Several emerging technologies are aiming to meet renewable fuel standards, mitigate greenhouse gas emissions, and provide viable alternatives to fossil fuels. Direct conversion of solar energy into fungible liquid fuel is a particularly attractive option, though conversion of that energy on an industrial scale depends on the efficiency of its capture and conversion. Large-scale programs have been undertaken in the recent past that used solar energy to grow innately oil-producing algae for biomass processing to biodiesel fuel. These efforts were ultimately deemed to be uneconomical because the costs of culturing, harvesting, and processing of algal biomass were not balanced by the process efficiencies for solar photon capture and conversion. This analysis addresses solar capture and conversion efficiencies and introduces a unique systems approach, enabled by advances in strain engineering, photobioreactor design, and a process that contradicts prejudicial opinions about the viability of industrial photosynthesis. We calculate efficiencies for this direct, continuous solar process based on common boundary conditions, empirical measurements and validated assumptions wherein genetically engineered cyanobacteria convert industrially sourced, high-concentration CO(2) into secreted, fungible hydrocarbon products in a continuous process. These innovations are projected to operate at areal productivities far exceeding those based on accumulation and refining of plant or algal biomass or on prior assumptions of photosynthetic productivity. This concept, currently enabled for production of ethanol and alkane diesel fuel molecules, and operating at pilot scale, establishes a new paradigm for high productivity manufacturing of nonfossil-derived fuels and chemicals.

76 FR 54291 - Notice of Rail Energy Transportation Advisory Committee Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-31

..., particularly, but not necessarily limited to, coal, ethanol, and other biofuels. The purpose of this meeting is..., a review and discussion of ethanol issues, a roundtable discussion, and election of new officers...

Ethanol consumption during pregnancy and lactation. Changes in the nutritional status of predominantly breastfeeding mothers.

PubMed

Villalpando, S; Flores-Huerta, S; Fajardo, A; Hernandez-Beltran, M J

1993-01-01

The purpose of this investigation was to study the effects of ethanol, consumed as a mild fermented beverage called "pulque", during pregnancy and lactation on the food intake and some anthropometric indices of body composition of a group of lactating mothers in a town in central Mexico. Thirty two mothers who drank pulque during pregnancy and lactation and 61 non-drinking women with comparable characteristics were evaluated anthropometrically, their dietary and ethanol intake recorded during a 6-month postpartum period. Energy [(8360 +/- 2997 vs. 7156 +/- 2177 J) and protein (52.7 +/- 20.9 vs. 44.6 +/- 16.1 g)] 24-h intake, height, weight, body mass index, arm muscle and fat areas were greater in drinking mothers than in controls. Average total ethanol consumption varied from 0.48 - 0.55 g-1 kg-1.d-1. Drinking mothers lost weight less frequently. Additional energy provided by pulque might explain such a difference. More precise information about the changes in their body composition and energy balance are in order for confirmation.

Initial solubility & density evaluation of Non-Aqueous system of amino acid salts for CO2 capture: potassium prolinate blended with ethanol and ethylene glycol

NASA Astrophysics Data System (ADS)

Murshid, Ghulam; Garg, Sahil

2018-05-01

Amine scrubbing is the state of the art technology for CO2 capture, and solvent selection can significantly reduce the capital and energy cost of the process. Higher energy requirement for aqueous amine based CO2 removal process is still a most important downside preventive its industrial deployment. Therefore, in this study, novel non-aqueous based amino acid salt system consisting of potassium prolinate, ethanol and ethylene glycol has been studied. This work presents initial CO2 solubility study and important physical properties i.e. density of the studied solvent system. Previous work showed that non-aqueous system of potassium prolinate and ethanol has good absorption rates and requires lower energy for solvent regeneration. However, during regeneration, solvent loss issues were found due to lower boiling point of the ethanol. Therefore, ethylene glycol was added into current studied system for enhancing the overall boiling point of the system. The good initial CO2 solubility and low density of studied solvent system offers several advantages as compared to conventional amine solutions.

Integrated bioethanol production to boost low-concentrated cellulosic ethanol without sacrificing ethanol yield.

PubMed

Xu, Youjie; Zhang, Meng; Roozeboom, Kraig; Wang, Donghai

2018-02-01

Four integrated designs were proposed to boost cellulosic ethanol titer and yield. Results indicated co-fermentation of corn flour with hydrolysate liquor from saccharified corn stover was the best integration scheme and able to boost ethanol titers from 19.9 to 123.2 g/L with biomass loading of 8% and from 36.8 to 130.2 g/L with biomass loadings of 16%, respectively, while meeting the minimal ethanol distillation requirement of 40 g/L and achieving high ethanol yields of above 90%. These results indicated integration of first and second generation ethanol production could significantly accelerate the commercialization of cellulosic biofuel production. Co-fermentation of starchy substrate with hydrolysate liquor from saccharified biomass is able to significantly enhance ethanol concentration to reduce energy cost for distillation without sacrificing ethanol yields. This novel method could be extended to any pretreatment of biomass from low to high pH pretreatment as demonstrated in this study. Copyright © 2017 Elsevier Ltd. All rights reserved.

High-throughput detection of ethanol-producing cyanobacteria in a microdroplet platform

PubMed Central

Abalde-Cela, Sara; Gould, Anna; Liu, Xin; Kazamia, Elena; Smith, Alison G.; Abell, Chris

2015-01-01

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. PMID:25878135

Suitability of anaerobic digestion effluent as process water for corn fuel ethanol fermentation.

PubMed

Wang, Ke; Zhang, Jian-Hua; Liu, Pei; Mao, Zhong-Gui

2014-01-01

A corn fuel ethanol plant integrated with anaerobic digestion treatment of thin stillage increases the net energy balance. Furthermore, the anaerobic digestion effluent (ADE) can be reused as a potential substitute for process water in the ethanol fermentation. In this study, the suitability of ADE as process water for corn ethanol fermentation was investigated by analyzing the potential inhibitory components in the ADE. It was found that ammonium influenced the growth and metabolism of Saccharomyces cerevisiae. Maximum ethanol production was obtained when the concentration of ammonium nitrogen was 200 mg/L, and ammonium could replace urea as the nitrogen source for S. cerevisiae under this concentration. In the ethanol fermentation with a higher concentration of ammonium, more glycerol was produced, thereby resulting in the decrease of ethanol production. In addition, components except ammonium in the ADE caused no inhibition to ethanol production. These results suggest that ADE could be reused as process water for corn ethanol fermentation without negative effect when ammonium concentration is well controlled.

The potential environmental impact of waste from cellulosic ethanol production.

PubMed

Menetrez, Marc Y

2010-02-01

The increasing production of ethanol has been established as an important contributor to future energy independence. Although ethanol demand is increasing, a growing economic trend in decreased profitability and resource conflicts have called into question the future of grain-based ethanol production. Growing emphasis is being placed on utilizing cellulosic feedstocks to produce ethanol, and the need for renewable resources has made the development of cellulosic ethanol a national priority. Cellulosic ethanol production plants are being built in many areas of the United States to evaluate various feedstocks and processes. The waste streams from many varying processes that are being developed contain a variety of components. Differences in ethanol generation processes and feedstocks are producing waste streams unique to biofuel production, which could be potentially harmful to the environment if adequate care is not taken to manage those risks. Waste stream management and utilization of the cellulosic ethanol process are equally important components of the development of this industry.

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...

DIRECT CONVERSION OF MUNICIPAL AND AGRICULTURAL WASTES TO BIODIESEL AND ETHANOL UTILIZING A UNIQUE EXTREMOPHILIC FUNGUS - PHASE I

EPA Science Inventory

Sustainable Bioproducts LLC’s proposed research will further develop an efficient, economical and scalable process for conversion of municipal solid wastes and agricultural wastes to biodiesel and ethanol. The technology is based on use of a novel extremophilic fun...

Cloning and Expression of Laccase from Trametes versicolor in Saccharomyces cerevisiae using a Novel Vector System

USDA-ARS?s Scientific Manuscript database

The long-term goal of this research is to increase efficiency and decrease cost of ethanol fermentation of lignocellulosic feedstocks by combining pre-treatment using laccase enzyme and subsequent fermentation to ethanol through simultaneous saccharification and fermentation paradigms. The first st...

Low-energy route for alcohol/gasohol recovery from fermentor beer. Final report

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

Mix, T.W.

1982-03-01

The production of gasohol directly from fermentor beer and gasoline is feasible and will enable a major reduction in the energy requirements for gasohol production. The fermentor beer is first enriched in a beer still to a 69 mol % ethanol, 31 mol % water product which is then dehydrated by extractive distillation with gasoline as the extractive agent. Gasohol is produced directly. In one version of the process, a heavy cut of gasoline, presumed available at a refinery before blending in of light components, is used as the extractive agent. The enriching column overhead vapors are used to reboilmore » the extractive distillation and steam stripping columns and to contribute to the preheating of the fermentor beer feed. Light components are blended into the heavy cut-ethanol bottom product from the extractive distillation column to form the desired gasohol. Energy requirements, including feed preheat, are 11,000 Btu per gallon of ethanol in the product gasohol. One hundred and fifty pound steam is required. In a second version, full range gasoline is used as the extractive agent. The enriching column overhead vapors are again used to reboil the extractive distillation and steam stripping columns and to contribute to the preheating of the fermentor beer feed. Light gasoline components recovered from the decanter following the overhead condenser of the extractive distillation column are blended in with the gasoline-ethanol product leaving the bottom of the extractive distillation column to form the desired gasohol. Energy requirements in this case are 13,000 Btu/gallon of ethanol in the product gasohol. In both of the above cases it is energy-conservative and desirable from a process standpoint to feed the enriched alcohol to the extractive distillation column as a liquid rather than as a vapor.« less

Life cycle assessment of lignocellulosic ethanol: a review of key factors and methods affecting calculated GHG emissions and energy use.

PubMed

Gerbrandt, Kelsey; Chu, Pei Lin; Simmonds, Allison; Mullins, Kimberley A; MacLean, Heather L; Griffin, W Michael; Saville, Bradley A

2016-04-01

Lignocellulosic ethanol has potential for lower life cycle greenhouse gas emissions compared to gasoline and conventional grain-based ethanol. Ethanol production 'pathways' need to meet economic and environmental goals. Numerous life cycle assessments of lignocellulosic ethanol have been published over the last 15 years, but gaps remain in understanding life cycle performance due to insufficient data, and model and methodological issues. We highlight key aspects of these issues, drawing on literature and a case study of corn stover ethanol. Challenges include the complexity of feedstock/ecosystems and market-mediated aspects and the short history of commercial lignocellulosic ethanol facilities, which collectively have led to uncertainty in GHG emissions estimates, and to debates on LCA methods and the role of uncertainty in decision making. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ethanol adaptation induces direct protection and cross-protection against freezing stress in Salmonella enterica serovar Enteritidis.

PubMed

He, S; Zhou, X; Shi, C; Shi, X

2016-03-01

Salmonella enterica serovar Enteritidis (Salm. Enteritidis) encounters mild ethanol stress during its life cycle. However, adaptation to a stressful condition may affect bacterial resistance to subsequent stresses. Hence, this work was undertaken to investigate the influences of ethanol adaptation on stress tolerance of Salm. Enteritidis. Salmonella Enteritidis was subjected to different ethanol adaptation treatments (2·5-10% ethanol for 1 h). Cellular morphology and tolerance to subsequent environmental stresses (15% ethanol, -20°C, 4°C, 50°C and 10% NaCl) were evaluated. It was found that 10% was the maximum ethanol concentration that allowed growth of the target bacteria. Ethanol adaptation did not cause cell-surface damage in Salm. Enteritidis as revealed by membrane permeability measurements and electron micrograph analysis. Salmonella Enteritidis adapted with 2·5-10% ethanol displayed an enhanced resistance to a 15%-ethanol challenge compared with an unchallenged control. The maximum ethanol resistance was observed when ethanol concentration used for ethanol adaptation was increased to 5·0%. Additionally, pre-adaptation to 5·0% ethanol cross-protected Salm. Enteritidis against -20°C, but not against 4°C, 50°C or 10% NaCl. Ethanol adaptation provided Salm. Enteritidis direct protection from a high level ethanol challenge and cross-protection from freezing, but not other stresses tested (low temperature, high salinity or high temperature). The results are valuable in developing adequate and efficient control measures for Salm. Enteritidis in foods. © 2016 The Society for Applied Microbiology.

Biocatalyzed processes for production of commodity chemicals: Assessment of future research advances for N-butanol production

NASA Technical Reports Server (NTRS)

Ingham, J. D.

1984-01-01

This report is a summary of assessments by Chem Systems Inc. and a further evaluation of the impacts of research advances on energy efficiency and the potential for future industrial production of acetone-butanol-ethanol (ABE) solvents and other products by biocatalyzed processes. Brief discussions of each of the assessments made by CSI, followed by estimates of minimum projected energy consumption and costs for production of solvents by ABE biocatalyzed processes are included. These assessments and further advances discussed in this report show that substantial decreases in energy consumption and costs are possible on the basis of specific research advances; therefore, it appears that a biocatalyzed process for ABE can be developed that will be competitive with conventional petrochemical processes for production of n-butanol and acetone. (In this work, the ABE process was selected and utilized only as an example for methodology development; other possible bioprocesses for production of commodity chemicals are not intended to be excluded.) It has been estimated that process energy consumption can be decreased by 50%, with a corresponding cost reduction of 15-30% (in comparison with a conventional petrochemical process) by increasing microorganism tolerance to n-butanol and efficient recovery of product solvents from the vapor phase.

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.

Heterobimetallic Zeolite, InV-ZSM-5, Enables Efficient Conversion of Biomass Derived Ethanol to Renewable Hydrocarbons

NASA Astrophysics Data System (ADS)

Narula, Chaitanya K.; Li, Zhenglong; Casbeer, Erik M.; Geiger, Robert A.; Moses-Debusk, Melanie; Keller, Martin; Buchanan, Michelle V.; Davison, Brian H.

2015-11-01

Direct catalytic conversion of ethanol to hydrocarbon blend-stock can increase biofuels use in current vehicles beyond the ethanol blend-wall of 10-15%. Literature reports describe quantitative conversion of ethanol over zeolite catalysts but high C2 hydrocarbon formation renders this approach unsuitable for commercialization. Furthermore, the prior mechanistic studies suggested that ethanol conversion involves endothermic dehydration step. Here, we report the complete conversion of ethanol to hydrocarbons over InV-ZSM-5 without added hydrogen and which produces lower C2 (<13%) as compared to that over H-ZSM-5. Experiments with C2H5OD and in situ DRIFT suggest that most of the products come from the hydrocarbon pool type mechanism and dehydration step is not necessary. Thus, our method of direct conversion of ethanol offers a pathway to produce suitable hydrocarbon blend-stock that may be blended at a refinery to produce fuels such as gasoline, diesel, JP-8, and jet fuel, or produce commodity chemicals such as BTX.

Heterobimetallic Zeolite, InV-ZSM-5, Enables Efficient Conversion of Biomass Derived Ethanol to Renewable Hydrocarbons.

PubMed

Narula, Chaitanya K; Li, Zhenglong; Casbeer, Erik M; Geiger, Robert A; Moses-Debusk, Melanie; Keller, Martin; Buchanan, Michelle V; Davison, Brian H

2015-11-03

Direct catalytic conversion of ethanol to hydrocarbon blend-stock can increase biofuels use in current vehicles beyond the ethanol blend-wall of 10-15%. Literature reports describe quantitative conversion of ethanol over zeolite catalysts but high C2 hydrocarbon formation renders this approach unsuitable for commercialization. Furthermore, the prior mechanistic studies suggested that ethanol conversion involves endothermic dehydration step. Here, we report the complete conversion of ethanol to hydrocarbons over InV-ZSM-5 without added hydrogen and which produces lower C2 (<13%) as compared to that over H-ZSM-5. Experiments with C2H5OD and in situ DRIFT suggest that most of the products come from the hydrocarbon pool type mechanism and dehydration step is not necessary. Thus, our method of direct conversion of ethanol offers a pathway to produce suitable hydrocarbon blend-stock that may be blended at a refinery to produce fuels such as gasoline, diesel, JP-8, and jet fuel, or produce commodity chemicals such as BTX.

Inhibitory effects of phenolic compounds of rice straw formed by saccharification during ethanol fermentation by Pichia stipitis.

PubMed

Wang, Xiahui; Tsang, Yiu Fai; Li, Yuhao; Ma, Xiubing; Cui, Shouqing; Zhang, Tian-Ao; Hu, Jiajun; Gao, Min-Tian

2017-11-01

In this study, it was found that the type of phenolic acids derived from rice straw was the major factor affecting ethanol fermentation by Pichia stipitis. The aim of this study was to investigate the inhibitory effect of phenolic acids on ethanol fermentation with rice straw. Different cellulases produced different ratios of free phenolic acids to soluble conjugated phenolic acids, resulting in different fermentation efficiencies. Free phenolic acids exhibited much higher inhibitory effect than conjugated phenolic acids. The flow cytometry results indicated that the damage to cell membranes was the primary mechanism of inhibition of ethanol fermentation by phenolic acids. The removal of free phenolic acids from the hydrolysates increased ethanol productivity by 2.0-fold, indicating that the free phenolic acids would be the major inhibitors formed during saccharification. The integrated process for ethanol and phenolic acids may constitute a new strategy for the production of low-cost ethanol. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mechanisms of yeast stress tolerance and its manipulation for efficient fuel ethanol production.

PubMed

Zhao, X Q; Bai, F W

2009-10-12

Yeast strains of Saccharomyces cerevisiae have been extensively studied in recent years for fuel ethanol production, in which yeast cells are exposed to various stresses such as high temperature, ethanol inhibition, and osmotic pressure from product and substrate sugars as well as the inhibitory substances released from the pretreatment of lignocellulosic biomass. An in-depth understanding of the mechanism of yeast stress tolerance contributes to breeding more robust strains for ethanol production, especially under very high gravity conditions. Taking advantage of the "omics" technology, the stress response and defense mechanism of yeast cells during ethanol fermentation were further explored, and the newly emerged tools such as genome shuffling and global transcription machinery engineering have been applied to breed stress resistant yeast strains for ethanol production. In this review, the latest development of stress tolerance mechanisms was focused, and improvement of yeast stress tolerance by both random and rational tools was presented.

Transport phenomena in alkaline direct ethanol fuel cells for sustainable energy production

NASA Astrophysics Data System (ADS)

An, L.; Zhao, T. S.

2017-02-01

Alkaline direct ethanol fuel cells (DEFC), which convert the chemical energy stored in ethanol directly into electricity, are one of the most promising energy-conversion devices for portable, mobile and stationary power applications, primarily because this type of fuel cell runs on a carbon-neutral, sustainable fuel and the electrocatalytic and membrane materials that constitute the cell are relatively inexpensive. As a result, the alkaline DEFC technology has undergone a rapid progress over the last decade. This article provides a comprehensive review of transport phenomena of various species in this fuel cell system. The past investigations into how the design and structural parameters of membrane electrode assemblies and the operating parameters affect the fuel cell performance are discussed. In addition, future perspectives and challenges with regard to transport phenomena in this fuel cell system are also highlighted.

Ethanol as an Alternative Fuel for Automobiles: Using the First Law of Thermodynamics to Calculate the "Corn-Area-per-Car" Ratio

ERIC Educational Resources Information Center

Pietro, William J.

2009-01-01

Students will use the first law of thermodynamics to determine the feasibility of using corn ethanol as an alternative to fossil fuels in automobiles. Energy flow is tracked from the Sun, to photosynthesized carbohydrate, to ethanol through fermentation, and finally to work in the combustion engine. Feasibility is gauged by estimating a…